US3787649A

US3787649A - Vacuum switch cam operating mechanism with contact loading compression spring

Info

Publication number: US3787649A
Application number: US00278177A
Authority: US
Inventors: H Erni; E Goodwin; O Larkin
Original assignee: Allis Chalmers Corp
Current assignee: Allis Chalmers Corp
Priority date: 1972-08-04
Filing date: 1972-08-04
Publication date: 1974-01-22
Anticipated expiration: 1991-01-22
Also published as: AU5861473A; CA985725A

Abstract

A single reciprocable cam bar simultaneously operates three vacuum interrupters. Cam follower motion is transmitted by precompressed contact loading springs to the movable contacts to assure high contact pressure, and the precompressed contact laoding springs exert substantially constant force regardless of the amount of contact erosion or overtravel. The cam bar is latched in switch closed position, and the forces of the three contact loading springs are additive to the force of the cam bar return springs to effect switch opening. Contact closing position is adjustable for each switch at a single point by varying deflection of the precompressed contact loading springs to thereby assure synchronized closing of the three interrupters. The motion of the contact operating rods is guided by pivoted yokes along a line substantially axial of the contacts to compensate for contact erosion.

Description

United States Patent 91 Goodwin, Jr. et al. a g

[ Jan. 22, 1974 [75] Inventors: Edwin C. Goodwin, Jr., Canton;

Oscar L. Larkin, Saugus, both of Mass.; Heinrich H. Erni, Turgi, Switzerland [73] Assignee: Allis-Chalmers Corporation,

Milwaukee, Wis.

22 Filed! Aug. 4, 1972 211 App]. No.: 278,177

52 us. c1.... 200/153 LA, 200/144 B, 200/153 H, 335/131, 335/191 511 1 pm 11011 33 42 HOlh 33/6 HOlh 3/42 [58] Field 61 Search... 200/144 B, 'i5'3TA, 1531i, 153 G; 335/106, 27, 127, 131, 190, 191;

6/1971 Brunner 200/144 B X 4/1966 Lindsay 200/144 B X Primary ExaminerI-Ierman J. Hohauser Assistant ExaminerRobert A. Vanderhye Attorney, Agent, or FirmRobert C. Jones; Robert B. Benson; Lee H. Kaiser [5 7] ABSTRACT A single reciprocable cam bar simultaneously operates three vacuum interrupters. Cam follower motion is transmitted by precompressed contact loading springs to the movable contacts to assure high contact pressure, and the precompressed contact laoding springs exert substantially constant force regardless of the amount of contact erosion or overtravel. The cam bar is latched in switch closed position, and the forces of the three contact loading springs are additive to the force of the cam bar return springs to effect switch opening. Contact closing position is adjustable for each switch at a single point by varying deflection of the precompressed contact loading springs to thereby assure synchronized closing of the three interrupters. The motion of the contact operating rods is guided by pivoted yokes along a line substantially axial of the contacts to compensate for contact erosion.

20 Claims, 9 Drawing Figures PAIENTED 3.787.649

SHEET 2 (IF 5 PATENTEDJAHZZW I 3. 781', 649

' SHEET 5 OF 5 xii VACUUM SWITCH CAM OPERATING MECHANISM WITIICONTACT LOADING COMPRESSION SPRING This invention relates to an operating mechanism for a plurality of vacuum interrupters.

DESCRIPTION OF THE PRIOR ART Operating mechanisms for a plurality of vacuum interrupters are known, but push-rods which actuate the vacuum interrupter contacts in certain prior art mechanisms are moved by a three-bar linkage which results in substantial lateral movement of the push-rods and consequent erosion of the contacts. Such three-bar linkage required critical initial factory setting and subsequent fine field adjustment to maintain stability. Further, interphase coordination was neither positively guided nor maintained throughout the operation sequence. Other prior art operating mechanisms for a plurality of vacuum interrupters use separate cams for their push-rods'with the result that it is difficult to syn chronize opening of and closing of the contacts for the vacuum interrupters and more difficult to maintain the interrupters in adjustment. Further, such prior art vacuum switch operating mechanisms require adjustment at numerous points in the operating mechanism of each interrupter in order to synchronize opening and closing of the plurality of interrupters. Certain prior art operating mechanisms for a plurality of vacuum interrupters have separate contact opening means for each interrupter, and such opening means occasionally do not have sufficient force to separate the interrupter contacts'if they freeze or become welded during use. Further, failure of one vacuum interrupter often caused dynamic unbalance of the three bar linkage operating mechanism of prior art vacuum switch actuating means and resulted in opening of all three interrupters.

OBJECTS OF THE INVENTION An object of the invention is to provide an improved actuator for a plurality of vacuum interrupters.

Another object of the invention is to provide a switch actuator having means for latching a plurality of interrupters in closed position and stored energy means for simultaneously opening the plurality of interrupters.

Yet another object of the invention is to provide a switch actuator having a single cam bar which effects simultaneous synchronized operation of the movable contacts of a plurality of electrical interrupters.

A further object of the invention is to provide an operating mechanism for a plurality of vacuum interrupters wherein all interrupter contacts are inherently synchronized and contact loading variation resulting from contact erosion is minimized.

A still further object is to provide an operating mechanism for a plurality of vacuum interrupters having means to correct each phase for deviations caused by manufacturing tolerances or by wear.

Still another object of this invention is to provide an actuator for a plurality of vacuum interrupters having a single support plate on which the operating mechanism and the tripping mechanism for the plurality of interrupters is mounted.

A further object of the invention is to provide an actuator for a plurality of vacuum interrupters which applies substantially axial closing forces simultaneously to the movable contacts of the interrupters.

and precompressed contact loading springs which exert v substantially-constant force and transmit closing motion to the movable contacts to thus prevent damage to the vacuum interrupters.

Still another object of the invention is to provide an improved actuator for a plurality of vacuum interrupters having precompressed contact loading spring means for holding the interrupter contacts closed with a substantially constant .force so that contact pressure remains uniform irrespective of erosion of the contacts.

Still another object of the invention is to provide an operating mechanism for a plurality of vacuum interrupters having precompressed contact loading spring means in each of the interrupters for effecting high pressure contact engagement and'wherein the forces of such contact loading spring means of all of the interrupters are additive to the force of the switch opening springs to break open the contacts of any one interrupter if they become welded during operation.

Yet another object of the invention is to provide an operating mechanism for a plurality of vacuum interrupters wherein the failure of one interrupter cannot cause dynamic imbalance of the operating mechanism which in prior art apparatus often resulted in opening of all interrupters when one vacuum interrupter failed.

A still further object of the invention is to provide an improved operating mechanism for three phase vacuum switches wherein contact closing for each interrupter is easily adjusted at a single point to accomplish synchronized closing of the three interrupters.

These and other objects and advantages of the invention will be more readily apparent from the following detailed description when considered in connection with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in front elevation of a three phase vacuum switch embodying the invention with parts broken away to show internal construction of a vacuum switch and of the switch operating mechanism;

FIG. 2 is a view in elevation, partly in vertical section, of the switch operating mechanism shown in FIG. 1;

FIG. 3 is a horizontal section view of the actuator taken along line III-Ill on FIG. 2;

FIG. 4 is a view similar to FIG. 2 showing the position of the various actuator components after the actuator has operated to close the contacts of the interrupters;

FIG. 5 is an enlarged fragmentary view in vertical section taken along line V-V of FIG. 2;

FIG. 6 is an enlarged fragmentary view in transverse vertical section taken through a hanger assembly which secures the mounting plate to the supporting base;

FIG. 7 is a schematic illustration of how substantially linear actuation of an interrupter movable contact is accomplished by the cooperative movement of a pivoted yoke and the push-rod in a contact closing (or opening) movement;

FIG. 8 is an enlarged fragmentary view partly in horizontal section and partly in plan of the latch mechanism taken along line VIII-VIII in FIG. 4; and

FIG. 9 is an enlarged fragmentary view of the end of the latch mechanism lever in latching engagement.

DESCRIPTION OF THE INVENTION FIG. 1 of the drawing shows a three phase vacuum switch 20 comprising three vacuum interrupters 21, 21a and 21b which are operated simultaneously by a switch actuator 24. The vacuum interrupters 21, 21a and 21b are identical and are bolted in an upright position on a supporting base 25 comprising the web of a horizontal structural channel member 26, which, in turn, is adapted to be mounted on a suitable supporting structure 27 shown in FIG. 2. The actuator 24 is likewise supported by the base 25 and is secured in depending relationship to the underside of the channel member 26 by means of

hanger assemblies

81 and 82 which are secured to the channel member 26 by bolts.

The vacuum interrupters 21, 21a and 21b are similar and the description of the switch 21 will likewise apply to interrupters 21a and 21b, and corresponding parts will be identified with the same reference number with an addition of a letter suffix to identify the particular interrupters and associated mechanism. The interrupter 21 includes a pair of ceramic hollow upper and

lower insulators

28 and 29 disposed in axial alignment. The lower insulator 29 is mounted in a lower metallic hollow cup member 31 which is bolted to the top surface of channel 26. The upper end of the insulator 29 receives a cup member 32 similar to the cup member 31. A similar arrangement is provided for the upper insulator 28 wherein there are provided lower and upper hollow

metallic cup members

33 and 34. A metallic terminal 36 having a clearance opening therethrough for the interrupter operating rod is interposed between the

cup members

32 and 33. The upper and

lower insulator members

28 and 29 are rigidly secured together by means of bolts 37 which extend through suitable aligned openings provided in terminal 36 and in the radial flanges of

cup members

32 and 33. A metallic cap terminal 38 is bolted or otherwise secured to the upper cup member 34 and serves as a support for a depending stationary contact rod 39 of the vacuum interrupter. The

cup members

31 and 32 associated with the lower insulator 29 are bonded thereto. by suitable bonding material such as Portland cement, epoxy resin or the like. In like manner, the

cup members

33 and 34 associated with the upper insulator 28 are likewise bonded thereto by the same type of bonding material.

The stationary contact rod 39 extends downwardly into a glass vacuum interrupter 41 that is supported in the hollow upper insulator 28. Vacuum interrupter 41 has a circumferential flange at its lower end which is fastened by screws (not shown) to the metallic terminal 36. A movable contact rod 42 extends through the bottom end of vacuum interrupter 41 and through the opening in terminal 36 in axial alignment with the stationary contact rod 39 and is movable into engagement with stationary contact 39. The movable contact 42 is shown in the open position and is movable axially into abutting engagement with the stationary contact 39 to complete an electrical circuit through the interrupter between

terminals

36 and 38. The ends of vacuum interrupter 41 through which the

contacts

39 and 42 extend are sealed in a well known manner.

An electrical connection is established between movable contact 42 and the terminal 36 by a plurality of electrically conductive flexible shunts 35. The shunts 35 are secured to the under surface of the terminal 36 and to the surface of a hollow metallic connector 40 which receives the end of movable rod contact 42.

The contact 42 is moved axially by an actuating rod or push-rod 43 of insulating material that extends up wardly through the insulator 29. The actuating rod 43 at its upper end is provided with the metallic connector 40 which receives the lower end of the movable contact rod 42. The lower end of the push-rod 43 is secured to parallel coupling members 44. As shown in FIG. 5, the lower end of the coupling members 44 are bifurcated so as to provide spaced

parallel legs

46 and 47 which extend downwardly between a pair of horizontally extending

arm portions

48, 49 of a pivoted U-shaped bracket yoke 51 which guides the movement of pushrod 43 in a straight line axial of movable contact rod 42. As shown in FIGS. 2, 3 and 5, bracket yoke 51 has spaced

arms

48 and 49 extending horizontally to the left disposed on opposite sides of

legs

46 and 47 and a pair of spaced arms 103 and 104 extending horizontally to the right. The

arms

48 and 49 are disposed between the

upstanding legs

52 and 53 of U-shaped stirrup 54.

The

leftwardly extending arms

48 and 49 of the pivoted U-shaped yoke 51 are disposed to bracket a horizontally reciprocable cam bar 55, FIG. 5, which effects simultaneous axial movement of the movable rod contacts 42, 42a and 42b of the three interrupters 21, 21a and 21b. A bolt 56 passes through suitably aligned openings in the

legs

52 and 53 of the U-shaped stirrup 54, through the arms 48 and49 of the bracket yoke 51, and through the

leg members

46 and 47 of the coupling members 44, as shown in FIG. 5. Rotatably mounted on bolt 56 is a cam follower roller 57 which is engaged in a cam slot 58 in the left end of the cam bar 55, as shown in FIGS. 2, 4 and 5.

As viewed in FIG. 5, the spaced

dependent legs

46 and 47 of the coupling members 44 receive the head 61 of a bolt 62 that extends downwardly through a suitable opening in the horizontal cross bar of the U-shaped stirrup 54. The head 61 of bolt 62 is secured to the depending ends of the

legs

46 and 47 by a pair of bolts 63, one of which is shown in FIG. 5, passing through clearance holes in head 61. Bolt 62 provides a positive connection between stirrup 54 and coupling members 44 during contact opening while permitting relative movement therebetween during contact closing so that the interrupter contacts can be held closed under high pressure by precompressed contact loading springs 66 and 67.

For the purpose of maintaining high pressure contact of the movable contact 42 with stationary contact 39 irrespective of the amount of overtravel of cam follower roller 57, a pair of concentric nested precompressed contact loading springs 66 and 67 are cooperatively arranged to transmit contact follower motion to the contact operating rod 43 and thus apply the required contact pressure to the movable contact 42 when it is in engagement with stationary contact 39. As shown in FIG. 5, the

springs

66 and 67 are of the compression type and are arranged in concentric nested relationship about the bolt 62. The inner spring 66 surrounds the bolt 62 so that its upper end engages the lower surface of the bolt head 61 and its lower end is in engagement with the cross bar of the U-shaped stirrup 54. The outer spring 67 is of the same compressed length as, but has a larger internal diameter than inner spring 66 and at its upper end engages the head 61 and at its lower end engages the cross bar of the U-shaped stirrup 54.

The lower depending end of the bolt 62 passes through a clearance hole in the cross bar of stirrup 54 and is threaded at 68 and receives a pair of interengaging nuts 69 and 71 which are self-locked on the bolt 62. Bolt 62 pre-compresses contact loading springs 66 and 67 to a predetermined deflection so that they exert a force which is substantially constant regardless of further deflection. When stirrup 54 is moved upwardly by cam follower roller 57, springs 66 and 67 urge coupling member 44 and push-rod 43 upwardly to actuate movable contact rod 42 into engagement with stationary contact 39 with the substantially constant force of

precompressed springs

66 and 67. This contact force remains substantially uniform regardless of limited overtravel of stirrup 54, and bolt 62 provides a positive connection between stirrup 54 and coupling members 44 during contact opening.

The operating means for movable contact 42 of interrupter 21 thus includes cam slot 58 in cam bar 55, cam follower roller 57, bolt 56 which couples cam follower S7 to stirrup 54, contact loading springs 66 and 67 which transmit contact closing motion from stirrup 54 to coupling members 44 and bolt 62 which preloads springs 66 and 67 and transmits contact opening motion to coupling members 44, contact operating rod 43 and movable contact rod 42, and bracket yoke 51 which at one end pivots about pin 98 and operatively engages bolt 56 at its other end to guide coupling members 44 is essentially straight linemotion as it is actuated by cam follower roller 57.

The cam bar 55 is reciprocable horizontally to effect the simultaneous upward movement of the push-

rods

43, 43a and 43b to actuate the movable contacts 42, 42a and 42b axially. As shown in FIGS. 2, 3'and 6, the cam bar 55 is slidably supported by supporting

strap assemblies

81 and 82 which are mounted in spaced relationship from the underside of the channel member 26. As shown in FIG. 6, the strap assembly 81 includes a pair of spaced L-shaped members 81a and 81b which are secured by

bolts

88 and 89 to

lugs

86 and 87 depending from channel member 26. The strap assembly 82 is similarly arranged and provided with a pair of L- shaped members 82a and 82b which are likewise secured in spaced relationship by means of

bolts

93 and 94 to

lugs

91 and 92 depending from the channel 26. The cam bar SSis movably supported for reciprocation between the L-shaped members 81a and 81b of the assembly 81 and between L-shaped members 82a and 82b of assembly 82 by

rollers

96 and 97 respectively which are rotatably supported on associated

bolts

98 and 99. The

rollers

96 and 97 are disposed in elongated horizontal guide slots 101' and 102 in the cam bar 55. The bolt 98 protrudes through clearance apertures in the spaced apart depending legs of L-shaped members 81a and 81b, and the bolt 98 also serves to support the rightwardly extending portions 103 and 104 of the U- shaped bracket yoke 51 so that yoke 51 pivots on bolt 98. A similar arrangement is provided for the bracket yoke 51b which has its leftwardly extending arms 106 and 107 connected by the bolt 99 on which the roller 97 is supported so that bracket yoke 51b pivots on bolt 99.

A component mounting plate 111 is supported in a vertical plane below cam bar in depending relationship from the

strap assemblies

81 and 82. As shown in FIG. 6 the plate 111 is disposed between and welded to the leg members 81a and 81b of the assembly 81 and also to the legs 82a and 82b of the assembly 82.

As shown in FIGS. 2 and 3, the bracket yoke 51a associated with the coupling member 44a has its leftwardly extending arms 48a and 49a supported by a bolt 98a that extends through aligned openings provided in the arms 48a and 49a. The bolt 98a is also provided with a roller member 119 similar to the

rollers

96 and 97. The roller 119 is disposed within an elongated horizontal guide slot 121 in cam bar 55. The bolt 98a is disposed in

upright strap members

122 and 123 that are welded on either side of the component mounting plate 111. Thus the cam bar 55 is movable in a horizontal plane, being guideably supported for movement by means of the

rollers

96, 97 and 119 which operate in the

guide slots

101, 102 and 121 respectively. As viewed in FIG. 2, the leftward movement of the cam bar 55 will move push-

rods

43, 43a and 43b upwardly for actuating the associated movable contacts 42, 42a and 42b associated with the interrupters 21, 21a and 21b. The vertical upward movement of the push-

rods

43, 43a and 43b upon leftward movement of the cam bar 55 is accomplished by cam slots 58, 58a and 58b in the cam bar 55. The cam slots 58, 58a and 58b are identical and the description for the cam slot 58 will apply to the cam slots 58a and 58b. As shown in FIG. 4, cam slot 58 has a lower horizontal cam track portion 126 and an upper horizontal cam track portion 127 which are connected by an upwardly inclined cam track portion 128. With the cam bar 55 located in its extreme position to the right, as depicted in FIG. 2, cam follower roller 57 associated with the push-rod coupling member 44 is located in the lower cam track portion 126 wherein the movable contact 42 is in open position, as shown in FIG. 1. As the cam bar 55 is moved to the left, the cam follower roller 57 tracking in the cam slot 58 is cammed upwardly following the upwardly inclined cam track portion 128 to the upper cam track portion 127. As the cam follower roller 57 tracks in the cam slot 48, stirrup 54, coupling members 44 and the push-rod 43 are moved axially upward, thereby moving the contact 42 into an abutting engagement with the stationary contact 39. The cam follower roller 57 is rotatably supported on the bolt 56 which passes through aligned openings in the upwardly extending

legs

52 and 53 of the stirrup member 54, through the

leftwardly extending arms

48 and 49 of the bracket yoke 51, and through vertically elongated openings 131 and 132 (See FIG. 5) in the depending

leg portions

46 and 47 respectively of the coupling members 44.- Thus, as the cam roller 57 tracks in the cam slot 58, the bolt 56 will move with the roller 57 and, in turn, will force leftwardly extending ends 48 and 49 of the bracket yoke 51 to pivot upwardly about the bolt 98. The bracket yoke 51 thereby causes bolt 56 to move in an arcuate path having bolt 98 as the center and thus operates to maintain the push-rod 43 in a vertical position so that it moves substantially in a straight line and the movable contact 42 engages in face-to-face abutting relationship with the stationary contact 39. As the bolt 56 moves upwardly with the cam follower roller 57, it moves within the

vertical openings

131 and 132 in the depending ends 46 and 47 of the coupling member 44 which movement of stirrup 54 is transmitted to coupling members 44 by

springs

66 and 67.

This pivotal connection between the bracket yoke 51 and the lower end of the coupling members 44 limits lateral movement of the lower end of the push-rod 43 so that it moves in a substantially straight line of movable contact 42.

This movement is best illustrated in FIG. 7 wherein the identifying reference numbers associated with the related mechanical components are utilized for the schematic showing of the parts. Thus, in FIG. 7 the point 56 represents the bolt 56 which is coaxial with cam follower roller 57 tracking in the cam slot 58. The arcuate line 131 represents the path followed by the bolt 56 as the cam follower roller 57 operates to close the contact 42. Point 98 in FIG. 7 represents the axis of bolt 98 about which the bracket yoke 51 pivots as the cam bar 55 moves to the left for closing the contacts 42. The lower horizontal line in FIG. 7 represents the lower cam track portion 126, the middle horizontal line represents the midpoint in the connecting inclined cam track portion 128, and the top horizontal line represents the upper cam track portion 127 wherein the full force of the contact loading springs 66 and 67 is exerted to maintain contact 42 in high pressure engagement with stationary contact 39. Thus, with the cam bar 55 in its full rightward position, depicted in FIG. 2, the contact 42 is in open position. In this position, the roller 57 is in the lower cam track portion 126. As the cam bar 55 is moved leftwardly, the roller 57 following the cam slot 58 moves out of the lower cam track portion 126 and up the inclined cam track portion 128. As the cam bar 55 moves leftwardly to effect closing of the contacts, the lower end of the pushrod 43, represented by the point 56 in FIG. 7, will move in an arcuate path represented by the line 131. Inasmuch as the vertical stroke of push-rod 43 is very small compared to the distance between bolt 56 and pivot point 98, it will be appreciated that bolt 56 can only move a very slight distance in the horizontal direction and that bracket yoke 51 guides push-rod 43 in an essentially straight line, or axial direction during opening and closing of the contacts. When roller 57 moves upwardly out of the inclined cam track portion 128 into the upper cam track portion 127 represented by the top horizontal line 127 in FIG. 7, the axis of the push-rod 43 and movable contact rod 42 are in the vertical plane represented by the line 130, thereby. insuring face-toface abutting engagement of the

contacts

42 and 39. The bracket yokes 51a and 51b associated with

pushrods

43a and 43b operate in the same manner as bracket yoke 51. Alllof the movable contacts 42, 42a and 42b engage their associated stationary contacts 39, 39a and 39b simultaneously when the

cam follower rollers

57, 57a and 57b are at the midpoint of their inclined

cam track portions

128, 128a and 128!) respectively. As the

cam follower rollers

57, 57a and 57b move beyond the midpoints of their associated inclined cam track portions 128, 128a and 128b respectively. As the

cam follower rollers

57, 57a and 57b move beyond the midpoints of their associated inclined cam track portions 128, 128a and 128b respectively, the preloaded contact loading springs 66-67, 66a-67a, and 66b-67b urge the movable contacts 42, 42a and 42b into high pressure engagement with the stationary contacts 39, 39a and 39b respectively, and such contact pressure remains substantially constant during any overtravel of the

stirrups

54, 54a, 54b as the cam follower rollers are cammed further up inclined cam track portions I28, 128a and l28b as described hereinafter, thereby preventing bounce and consequent erosion of the movable contacts 42, 42a and 42b.

Known operating mechanisms for three phase vac uum switches use a three-bar linkage which causes considerable lateral movement of the push-rod and results in contact erosion and contact bounce. It will be noted that push-

rods

43, 43a and 43b are free-floating and are guided by bracket yokes 51, 51a and 5 lb and from the

cam follower rollers

57, 57a and 57b so that they move free of slide cam bar 55. Further, the center of cam slots 58, 58a and 58b is at the same horizontal level as the guide slots 10l, 102 and I2] and is at the point of contact engagement. In this manner longitudinal movement of the push-

rods

43, 43a and 43b is positively controlled so that contact bounce is eliminated and lateral movement of the push-rods is limited so that contact erosion is minimized.

In accordance with the invention the contact loading springs 66-67, 66a-67a, and 66b-67b are loaded to a predetermined substantially constant force so that high contact pressure is maintained even though the contacts erode.

For affecting simultaneous closing of the three switches, the nuts 69, 69a and 69b are adjusted on the end of the threaded portions of the

bolts

62, 62a and 62b respectively. To this end, the cam bar 55 is moved leftwardly from the open switch position in which it is shown in FIG. 2 to a half stroke position wherein the

cam follower rollers

57, 57a and 57b are midway up the inclined cam track portions 128, 128a and l28b respectively At this point a pin (not shown) is inserted through an opening 136, FIG. 1, in the L-shaped leg member 82a of the hanger assembly 82 when it registers with an opening (not shown) in the cam bar 55 to lock the cam bar 55 in said half-stroke position. The nut 69 is then turned relative to bolt 62 to move coupling members 44 upwardly or downwardly until movable contact 42 just engages stationary contact 39. In a similar manner, the nuts 69a and 69b associated with the push-

rods

43a and 43b are adjusted so that movable contacts 42a and 42b just engage the stationary contacts 39a and 39b at the half-stroke position so that contact closing is synchronized in all three phases. When the desired adjustment has been efected, the pin (not shown) is removed from the aperture 136 to release the cam bar 55. Known operating mechanisms for three phase vacuum switches require adjustment at a plurality of points in each switch to synchronize closing of the three interrupters, and it will be appreciated that the disclosed structure requires adjustment at only one point on each interrupter actuator to synchronize contact closing in all three phases.

The contact pressure remains substantially constant irrespective of the amount of overtravel or of contact erosion. In the preferred embodiment the contact pressure is approximately 88 pounds and varies only plus or minus four pounds from initial contact engagement until the end of the cam stroke. If the contacts of one interrupter freeze (weld) due to arcing, the predetermined force of the precompressed springs 66-67, 66a-67a and 66b-67b of all three phases are additive to separate the contacts.

In order to close the vacuum switches 21, 21a and 21b, an actuating mechanism 141 is provided to move cam bar 55 to the left. Actuating mechanism 141 may be electrically or manually operated as desired. As shown in FIGS. 2 and 3, the actuating mechanism 141 includes a pair of generally triangularly shaped bell crank levers 142 and 143 which are pivotally connected to the cam bar 55 on opposite sides thereof by a pin 146, as shown in FIG. 3. The bell crank levers 142 and 143 are fulcrumed on opposite sides of mounting plate 111 by a pin 144 extending through plate 111.

Pivotal movement of the bell crank levers 142 and 143 about the fulcrum pin 144 in a counterclockwise direction, as viewed in FIG. 2, will effect the leftward movement of the cam bar 55 and closing or interrupters 21, 21a and 21b. The bell crank levers 142 and 143 are latched in their counterclockwise position to maintain the interrupters 21, 21a and 21b closed. For latching the bell crank levers 142 and 143, as depicted in FIG. 4, a latch mechanism 150 engages a latch pin 55 that extends through one leg of both of the bell crank levers 142 and 143. The latch mechanism 150 includes a latch trip lever 151 having depending bifurcated legs 152 and 153 and which is pivotally supported on a pin 154 extending through legs 152 and 153 and through a protrusion 156 of the mounting plate 111 at a cutout portion 160 of the mounting plate. Latch trip lever 151 is pivotally supported by the pin 154 with the bifurcated depending legs 152 and 153 disposed on opposite sides of the mounting plate 111 and is biased in a counterclockwise direction. The latch trip lever 151 also includes an upstanding thumb portion 157 which is operative to engage under the latch pin 155 that extends through the bell crank levers 142 and 143 at cutout portion 160. When the interrupters are open and the bell crank levers 142 and 143- are in their unlatched clockwise position, the latch pin 155 is disposed adjacent the side of the thumb portion 157 in the dotted line position shown in FIG. 9. As the bell crank levers 142 and 143 are pivoted in a counterclockwise direction to the latched position wherein the switch contacts are held closed, the latch pin 155 rides up and over an inclined surface 158, FIG. 9, of the thumb portion 157 to the solid line position shown in FIG. 9 wherein it rests on an arcuate surface 159 on thumb portion 157. With the bell crank levers 142 and 143 in full counterclockwise pivoted position, the upper arcuate surface 159 of the thumb portion 157 will move under the latch pin 155 to latch the bell crank levers 142 and 143. As best shown in FIG. 8, the depending leg 153 of the latch trip lever 151 is provided with a laterally extending finger 161. A tension spring 162 is secured at one end to the finger 161 and at'its opposite end to a bolt 163 which is threadedly engaged in the mounting plate 111 and extends outwardly therefrom; Thus the latch trip lever 151 is biased by spring 162 so that the thumb portion 157 is moved in a counterclockwise direction to bring arcuate surface 159 under pin 155 upon counterclockwise pivotal movement of the bell crank levers 142 and 143.

A stop screw 164 threadedly engaged in the outer end of the finger 161 is arranged to abut a stop 166 affixed to mounting plate 111 to limit thecounterclockwise movement of the thumb portion 157 at the solid line position shown in FIG. 9. In this latched position of bell crank levers 142 and 143, a radius drawn from pin 154 as a center through the latch pin 155 will pass through the arcuate surface 159 slightly to the right of the junction of the inclined surface 158 and the arcuate surface 159. In a preferred embodiment the adjustment is such that when the thumb portion 157 is in engage ment with the latch pin 155, the pin engages arcuate surface 159 at a distance A shown in FIG. 9 no greater than one eighth of an inch from the junction of the inclined surface 158 with the arcuate surface 159. This arrangement has been found most advantageous in effecting instantaneous tripping since the only force required is that needed to overcome the coefficient of rolling friction, and a trip solenoid 201 is only required to impart a slight clockwise rotation to leg 152 of the latch trip lever 151 to release bell crank levers 142 and 143 and thus permit return of the cam bar 55 to the right to open the switches.

Clockwise pivotal movement of the bell crank levers 142 and 143 from their latch position, as depicted in FIG. 4, to their unlatched position, depicted in FIG. 2, to open the interrupters is effected principally by a pair of

interrupters opening springs

172 and 173 disposed on opposite sides of mounting plate 111 and afixed at one end to a pin 174 extending through mounting plate 111 and at their opposite end to a pin 175 extending through both bell crank levers 142 and affixed above mounting plate 111. As the bell crank levers 142 and 143 are pivoted in a counterclockwise direction to close the interrupters, interrupter opening springs 172 and 173 are placed in tension so that the energy stored therein will effect clockwise pivotal movement of the bell crank levers 142 and 143 to open the interrupters upon tripping of the latch mechanism 150.

Power actuation of the bell crank levers 142 and 143 in a counterclockwise direction to close the interrupters 21, 21a and 21b is accomplished by a switch closing solenoid secured to a horizontally extending plate 181 that is welded to a lower surface of mounting plate 111 adjacent the left end thereof. The solenoid 189 is provided with a plunger 182 that is axially reciprocable within a cutout port on in mounting plate 111 when the solenoid 180 is energized. The plunger 182 is connected to the lower left leg of the bell crank levers 142 and 143 by links 183 and 184. The links 183 and 184 are pivotally connected at their upper ends to the bell crank levers 142 and 143 by a pin 186, and the lower ends of the links 183 and 184 bracket the plunger 182 and are connected thereto by a pin 187 that extends through the plunger 182. Switch closing solenoid 180 may be energized from a battery (not shown) in an electrical circuit completed by a remote manual switch (not shown) or suitable automatic relaying means, and energization of the solenoid 180 attracts the plunger 182 downwardly so that the bell crank levers 142 and 143 are pivoted about the fulcrum pin 144 in a counterclockwise direction, thereby moving the cam bar 55 to the left and closing the switches. Closing solenoid 180 is selected to have a sufficiently high attractive force for plunger 182 to impart high dynamic speed to the operating mechanism so that switches 21, 21a and 21b close within a half cycle to prevent restrikes and high frequency transients but which attractive force is not high enough to cause contact bounce.

As shown in FIGS. 2, 3 and 4, a manual switch actuating lever 191 rotatable in opposite directions for closing and for tripping the switches is secured to a shaft 192 that is rotatably supported in the mounting plate 111. As viewed in FIGS. 2 and 3, upwardly inclined cam operating arm 193 disposed adjacent to the cam bar 55 is secured to shaft 192 for rotation therewith. The upper end of the arm 193 is provided with an elongated slot 194 which receives a pin 196 secured in the cam bar 55 as shown in FIGS. 2 and 3. Counterclockwise rotation of switch actuating lever 191 will rotate shaft 192 and pivot arm 193 in a counterclockwise direction to move cam bar 55 to the left through the connection established between slot 194 and pin 196. As the arm 193 pivots counterclockwise, it will force the cam bar 55 to move leftwardly, FIG. 2, without imparting an upward force to the cam bar which would tend to displace it from the horizontal because of the elongated slot 194 which permits free movement of the pin 196 upwardly of the cam bar.

The manual switch actuating lever 191 is also operable in the clockwise direction to trip the latch mechanism 150 and permit the cam bar 55 to return to the right and thus open the vacuum switches. To this end, a trip solenoid plunger actuating arm 195 is connected to the shaft 192 for rotation therewith. The lower end of the arm 195 is urged by a spring 197 into engagement with the outer end of an actuating rod 198 (See FIG. 2) which is supported in a bracket 199 that is attached to trip solenoid 201 so that rod 198 is aligned with plunger 204 of trip solenoid 201. The trip solenoid 201 may be mounted by bolts (FIG. 8) to the front face of mounting plate 1 11 so that trip solenoid plunger 204 is adjacent trip lever 151. The rod 198 is maintained in its outward position by means of a spring 202 surrounding rod 198 and which at one end abuts against the bracket199 and at its opposite end abuts against a washer 203, FIG. 2, which bears against a pin extending transversely through the rod 198. Movement of the rod 198 to the left, as seen in FIG. 2, will engage the rod 198 with the end of plunger 204 of trip solenoid 201, thereby causing the plunger 204 to move axially to the left, as viewed in FIG. 2. When solenoid plunger 204 moves to the left it engages a horizontally extending finger 206 (See FIG. 8) that is integral with leg 152 of the bifurcated latch lever 151. With the latch mechanism 150 in the switch open position depicted in FIG. 2, the spacing between the horizontally extending finger 206 of the latch lever leg 152 and the trip solenoid plunger 204 is sufficient to allow the spring biased thumb portion 157 of the latch lever 151 to pivot in a counterclockwise direction under the roller 155 to latch the operating mechanism. With the cam bar 55 in its leftward position shown in FIG. 4 wherein the contacts of the interrupters are closed, the thumb portion 157 will be biased in a counterclockwise direction by the spring 162 so that the arcuate surface 159 of the thumb member 157 engages under the latch pin 155. With this condition obtained, the horizontally extending finger portion 206 will be in engagement with the outer end of the solenoid plunger 204. As described hereinbefore, only a small force is required to pivot latch lever 151 and trip the operating mechanism, and spring 202 exerts a counter force against arm 195 and prevents inadvertent tripping of the switch such as might otherwise be caused by the weight of a hotstick engaged in the eye at the end of the switch actuating lever 191.

Tripping of the switch operating mechanism may be accomplished automatically through energization of the trip solenoid 201, thereby moving solenoid plunger 204 to the left to pivot the latch lever 151 in a clockwise direction about the pin 156 and moving the thumb portion 157 out of engagement with the latch pin 155. This releases the bell crank levers 142 and 143 so that they pivot in a clockwise direction about the fulcrum pin 144 under the influence of the stored energy in the switch opening springs 172 and 173 aided by the additive force of contact loading springs 6667, 66a-67a and 66b-67b. This will effect a rightward movement of the cam bar 55, thereby disengaging the movable contacts 42, 42a and 42b of the switches 21, 21a and 21b from the stationary contacts 39, 39a and 39b.

To manually trip the switch operating mechanism, the switch actuating handle 191 is pivoted downwardly in a clockwise direction from the position shown in FIG. 4, thereby rotating the shaft 192 and lever 195 so that it pushes the rod 198 and solenoid plunger 204 leftwardly. Leftward movement of the solenoid plunger 294 will engage it with the extending finger 206 of the leg 152 of the latch lever 151, thereby pivoting the latch lever 151 in a clockwise direction to release the bell crank levers 142 and 143. The stored energy in the

springs

172 and 173 then pivot the bell crank levers 142 and 143 about the fulcrum pin 144 in a clockwise direction, thereby forcing the cam bar 55 to move rightwardly to open the switches.

As can be seen in FIG. 1, the switch actuating mechanism 24 is protected both from the weather and damage by a cabinet enclosure 208 which is in the form of an envelope having an open upper end which engages the under surface of the channel member 26. The cabinet enclosure 208 is held in position by bolts 209 engaged within internally threaded lugs 210 that are welded or otherwise secured to the lower surface of the mounting plate 1 11.

From the foregoing description, it can be readily seen that a rugged and simplified arrangement has been provided in which a single cam bar 55 effects the simultaneous opening or closing of a plurality of vacuum interrupters. It will also be apparent that the single mounting plate 111 for supporting the operating mechanisms for the three phase vacuum switch results in a superior and simplified structure that is economical to produce yet rugged in construction.

With the arrangement described, it will be apparent that if the contacts of one of the vacuum switches should freeze or weld, the additive forces of all the nested contact loading springs 66 and 67, 66a and 67a and 66b and 67b associated with the push-rods 43, a and 43b cooperate with the stored energy switch opening springs 172 and 173 to break the welded contacts apart. v

It is also apparent that the cam slots 58, 58a and 58b being formed in the manner depicted with the upper track portions parallel to the direction of cam bar reciprocation prevent overtravel of the movable contacts 21, 21a and 21b, thereby preventing damage to the vacuum interrupter bottles.

It should be understood that we do not intend to be limited to the single embodiment shown and described for many modifications and variations thereof will be obvious to those skilled in the art.

We claim:

1. In an electric circuit breaker having at least three interrupters in parallel vertical array, said interrupters each having a pair of separable contacts one of which is stationary and the other of which is axially movable into and out of engagement with said stationary contact;

operating means including a cam follower operably connected to each of said axially movable contacts for actuating all of said contacts simultaneously in the same direction into and out of engagement with their associated stationary contacts;

an elongated cam bar supported for reciprocal movement in a direction transverse to the direction in which said movable contacts are movable;

a plurality of identical cam slots formed in said cam bar, one for each movable contact, said cam slots being disposed along a common axis, said cam slots having identical configurations including a cam track portion inclined at an oblique angle to the direction of cam bar reciprocation, each cam slot also including a cam track portion at each end of said inclined portion, said cam slots each operatively receiving 'a cam follower;

a pivoted yoke for each cam follower and operatively connected to each cam follower for guiding the lower end of said contact in such a manner that in the closing movement said movable contacts move in an arcuate path of travel that terminates on a line that includes the axes of the contacts when said contacts are in closed position to thereby provide a wiping engagement between the contact faces of said contacts; and,

a contact loading compression spring for each of said contacts, said loading compression spring being supported in position to provide for predetermined high pressure engagement between the movable contact and an associated stationary contact irrespective of the amount of over travel of an associated cam follower,

whereby movement of said cam bar in one direction will effect simultaneous movement of all of said movable contacts in the same direction into engagement with their associated stationary. contacts and upon movement of said cam bar in the opposite direction all of said movable contacts will move simultaneously in the same direction to open positions.

2. An electric circuit breaker in accordance with claim 1 wherein eachof said cam followers include a roller disposed in an associated one ofsaid cam slots and said cam bar has a plurality of guide grooves therein elongated in the direction of reciprocation of said cam bar, and wherein said circuit breaker also has means including guide grooves and guide rollers disposed in said guide grooves for guiding said cam bar in its direction of reciprocation and preventing movement thereof in all directions transverse to its direction of reciprocation.

3. In an electric circuit breaker having at least three vacuum interrupters in parallel vertical array, said interrupters each having a pair of separable contacts one of which is stationary and the other of which is axially movable into and out of engagement with said stationary contact;

operating means including a cam follower operably connected to each of said axially movable contacts for actuating all of said contacts simultaneously in the same direction into and out of engagement with their associated stationary contacts, said operating means including contact loading compression spring means for transmitting contact closing motion of each of said cam followers to each of said movable contacts, and means for deflecting each of said contact loading compression spring means to a predetermined loading and for providing a positive connection between said associated cam follower and said associated movable contact when said cam follower is moved in contact opening direction and each being adjustable to vary said predetermined loading; an elongated cam bar supported for reciprocal movement in a direction transverse to the direction in which said movable contacts are movable; a plurality of identical cam slots formed in said cam bar one for each movable contact, said cam slots being disposed along a common axis, said cam slots having identical configurations including a cam track portion inclined at an oblique angle to the direction of cam bar reciprocation, each cam slot also including a cam track portion at each end of said inclined portion, said cam slots each operatively receiving a cam follower; pivoted bell crank lever having an arm pivotally connected to said reciprocable cam bar; preloaded contact opening spring means engaging an arm of said bell crank lever and further loaded when said cam bar is reciprocated in a direction to close said contacts of said plurality of vacuum interrupters; and, latch means adapted to releasably engage an arm of said bell crank lever for holding said bell crank lever and said cam bar in a position wherein said contacts of said plurality of interrupters are closed,

whereby the forces of said plurality of contact loading compression spring means-and of said contact opening spring means are additive to open said plurality of vacuum interrupters.

4. An electric circuit breaker in accordance with claim 3 and including a trip solenoid provided with an armature movable when said solenoid is energized from a released position wherein said latch means can latch said bell cranklever to a trip position wherein said solenoid trips said latch means to free said bell crank lever, said armature having a portion accessible from the exterior of said trip solenoid, a pivoted switch operating handle engaging said accessible portion of said armature and being adapted to move said armature from said released position to said trip position, and spring means engaging said accessible portion of said armature for normally holding said armature in said released position and thereby preventing inadvertent opening of said vacuum switch contacts when said operating handle is engaged with a hot stick.

5. In an electric circuit breaker, in combination;

a supporting base;

a plurality of vacuum interrupters mounted in spaced relation on said base in a plane transverse to said base and each having a stationary contact, movable contact, and means including a cam follower for operating said movable contact into and out of engagement with said stationary contact;

elongated reciprocable cam bar means having a plurality of cam slots therein each of which has a cam track portion oblique to the direction of cam reciprocation receiving one of said cam followers for simultaneously actuating said movable contact operating means of said plurality of vacuum interrupters;

means affixed to said supporting base for guiding and supporting said cam bar for reciprocation in said plane transverse to said base;

a mounting plate, said cam bar guiding means supporting said mounting plate in said plane transverse to said base;

bell crank lever means pivoted on said mounting plate and having one arm operatively connected to said reciprocable cam bar;

switch opening spring means affixed at one end to an arm of said bell crank lever means and at the other end to said mounting plate and being further loaded when said cam bar is reciprocated in the switch closing direction;

latch means pivotally supported on said mounting plate for latching said bell crank lever when said cam bar is in switch closing position; and

trip solenoid means affixed to said mounting plate for releasing said latch means to free said bell crank lever means when said trip solenoid is energized.

'6. An electric circuit breaker in accordance with claim 5 and including a closing solenoid supported on said mounting plate and having a plunger operatively connected to an arm of said bell crank lever means for actuating said cam bar to switch closing position when said closing solenoid is energized.

7. An electric circuit breaker in accordance with claim 6 wherein said trip solenoid is provided with an armature movable when said trip solenoid is energized from a released position wherein said latch means can latch said bell crank lever means to a trip position wherein said trip solenoid armature trips said latch means to free said bell crank lever means, said trip solenoid armature having an accessible portion;

a switch operating handle pivotally supported on said mounting plate and being adapted to move said trip solenoid armature from said released position to said trip position; and,

spring means engaging said accessible portion of said trip solenoid armature for normally holding said armature in said released position, thereby preventing inadvertent opening of said vacuum interrupter contacts when said operating handle is engaged with a hot stick.

8. An electric circuit breaker in accordance with claim 5 whereinsaid cam bar guiding and supporting means includes'a plurality of aligned pairs of cam guide legs projecting from the side of said supporting base opposite that on which said vacuum interrupters are mounted and with the legs of each said pair being spaced apart and disposed on opposite sides of a plane transverse to said base and of said cam bar and affixed adjacent their ends to said mounting plate.

9. An electric circuit breaker in accordance with claim 8 wherein said cam bar has a plurality of cam grooves therein elongated in the direction of cam bar reciprocation each of which is adjacent one of said pairs of cam guide legs, and said cam bar guiding and supporting means includes said cam grooves, a roller in 1 each of said cam grooves, and a roller support member extending through each said pair of cam guide legs and revolvably supporting one of said rollers with the corresponding cam groove.

10. An electric circuit breaker in accordance with claim 9 wherein each said movable contact operating means includes yoke means pivotally mounted at one end on one of said roller support members and operatively connected at the other end to one of said cam followers for guiding said movable contact in a manner to insure substantial face-to-face engagement between contacts when in closed positions.

11. An electric circuit breaker in accordance with claim 10 wherein each said movable contact operating means also includes an elongated, longitudinally reciprocable, insulated contact operating rod operatively connected at one end to the associated movable contact and precompressed contact loading compression spring means for transmitting switch closing cam follower motion to the other end of said contact operating rod.

12. In an electric circuit breaker having at least three interrupters in parallel vertical array, said interrupters each having a pair of separable contacts one of which is stationary and the other of which is axially movable into and out of engagement with said stationary contact;

a plurality of identical cam slots formed in said cam bar one for each movable contact, said cam slots being disposed along a common axis, said cam slots having identical configurations including a cam track portion inclined at a oblique angle to the direction of cam bar reciprocation, each slot also including a cam track portion at each end of said inclined portion, said cam slots each operatively receiving a cam follower;

an elongated, longitudinally reciprocable, insulated contact operating rod for each axially movable contact, said operating rods being operatively connected to an adjacent end of an associated movable contact;

precompressed contact loading compression spring means for transmitting switch closing cam follower motion to the other end of each of said contact rods;

a U-shaped stirrup bracketing each of said cam followers and an associated contact operating rod, each of said U-shaped stirrups having the legs thereof operatively coupled to an associated cam follower, said contact loading compression spring means being adaptedto react at its opposite ends against the cross piece of said U-shaped stirrup and against said other end of said associated contact operating rod;

adjustable bolt means affixed to said other end of each of said contact operating rods for precompressing said contact loading compression spring means against the cross piece of said U-shaped stirrup and for varying the stroke of said contact operating rod resulting from switch closing motion of said cam follower; and,

a pivoted member for each of said cam followers operatively connected to an adjacent end of an associated insulated contact operating rod for guiding the movement of the adjacent lower end of an asso ciated movable contact in an arcuate path of travel that terminates on a line that includes the axes of said contacts when said contacts are in closed position to thereby provide a wiping engagement between the contact faces of said contacts.

13. In an electric circuit breaker having at'least three vacuum interrupters in parallel vertical array, said interrupters each having a pair of separable contacts one of which is stationary and the other of which is axially movable into and out of engagement with said stationary contact;

operating means including a cam follower operably connected to each of said axially movable contacts for actuating all of said contacts simultaneously in the same direction into an out of engagement with their associated stationary contacts;

a plurality of identical cam slots formed in said cam bar one for each movable contact, said cam slots being disposed along a common axis, said cam slots having identical configurations including a cam truck portion inclined at an oblique angle to the direction of cam bar reciprocation, each cam slot also including a cam track portion at each end of said inclined portion, said cam slots each operatively receiving a cam follower;

a U-shaped stirrup bracketing each of said cam followers and said other end of an associated contact operating rod;

individual bolt means extending through the legs of each of said stirrups and through said associated cam followerfor coupling said stirrups to said cam followers, wherein said contact loading compression spring means react at one end against the cross piece of associated stirrups and at the opposite end against said other end of an associated contact operating rod;

individual bolt means affixed to said other end of each of said contact operating rods and extending through an associated contact loading compression spring means and through a clearance aperture in the cross piece of an associated stirrup for adjusting the position of said operating rod relative to the cross piece of its associated U-shaped stirrup to thereby provide means for varying the preloading of said contact loading compression spring means and the stroke of said contact operating rod as desired; and,

a pivoted member for each of said insulated contact operating rod operatively connected to an adjacent end of an associated cam follower for guiding the movement of the adjacent lower end of an associated movable contact in an accurate path of travel that terminates on a line that includes the axes of said contacts when said contacts are in closed position to thereby provide a wiping engagement between the contact faces of said contacts.

14. in an electric circuit breaker, in combination;

a supporting base;

a plurality of vacuum interrupters mounted in spaced relation on said base in a plane transverse to said base and each having a stationary contact, a movable contact, and means including a cam follower for operating said movable contact into and out of engagement with said stationary contact;

latch means pivotally supported on said mounting plate for latching said bell crank lever when said cam bar is in switch closing position;

trip solenoid means affixed to said mounting plate for releasing said latch means to free said bell crank lever means when said trip solenoid is energized, said trip solenoid being provided with an armature movable when said trip solenoid is energized from a released position wherein said latch means can latch said bell crank lever means to a trip position wherein said trip solenoid armature trips said latch means to free said bell crank lever means, said trip solenoid armature having an accessible portion;

a switch operating handle pivotally supported on said mounting plate and being adapted to move said trip solenoid armature from said released position to said trip position, said switch operating handle having a lever arm operatively connected to said cam bar, wherein manual operation of said handle in one direction reciprocates said cam bar to switch closing position and operation thereof in the opposite direction actuates said trip solenoid armature to said trip position to release said latch means;

spring means engaging said accessible portion of said trip solenoid armature for normally holding said armature in said released position, thereby preventing inadvertent opening of said vacuum interrupter contacts when said operating handle is engaged with a hot stick; and,

a closing solenoid supported on said mounting plate and having a plunger operatively connected to an arm of said bell crank lever means for actuating said cam bar to switch closing position when said closing solenoid is energized.

15. In an electric circuit breaker, in combination;

a supporting base;

a plurality of vacuum interrupters mounted in spaced relation on said base in a plane transverse to said base and each having a stationary contact, a movable contact, and means including a cam follower for operating said movable contact into and out of engagement with said stationary contact, each said movable contact operating means includes yoke means pivotally mounted at one end on one of said roller support members and operatively connected at the other end to one of said cam followers for guiding said movable contact in essentially straight line axial motion as it is actuated between open and closed positions, each said movable contact operating means also includes an elongated, longitudinally reciprocable, insulated contact operating rod operatively connected at one end to the associated movable contact and precompressed contact loading compression spring means for transmitting switch closing cam follower motion to the other end of said contact operating rod;

each said movable contact operating means also includes a U-shaped stirrup bracketing said contact loading compression spring means and having the legs thereof operatively connected to said cam follower, and wherein said contact loading spring means react at one end against the cross piece of said U-shaped stirrup and at the opposite end against said other end of said contact operating rod;

means affixed to said supporting base for guiding and supporting said cam for reciprocation in the plane transverse to said base;

said cam bar guiding and supporting means includes a plurality of aligned pairs of cam guide legs projecting from the side of said supporting base opposite that on which said vacuum interrupters are mounted and with the legs of each said pair being spaced apart and disposed on opposite sides of the plane'transverse to said base and of said cam bar and affixed adajcent their ends to said mounting plate;

said cam bar has a plurality of cam grooves therein elongated in the direction of cam bar reciprocation each of which is adjacent one of said pairs of cam guide legs, said cam bar guiding and supporting means includes said cam grooves, a roller in each of said cam grooves, and a roller support member extending through each said pair of cam guide legs and revolvably supporting one of said rollers within the corresponding cam groove;

a mountingplate, said cam bar guiding means supporting said mounting plate in the plate transverse to said base;

latch means pivotally supported on said mounting plate for latching said bell crank lever when said cam bar is in switch closing position; and,

a trip solenoid affixed to said mounting plate for releasing said latch means to free said bell crank lever means when said trip solenoid is energized.

16. An electric circuit breaker in accordance with claim 15 wherein each said movable contact operating means includes bolt means affixed to said other end of said contact operating rod and extending through a clearance aperture in said cross piece of said stirrup for adjusting the deflection of said contact loading spring means and the stroke of said contact operating rod resulting from contact closing motion of said cam follower.

l7. An electric circuit breaker in accordance with claim 16 wherein each said cam slot in said cam bar also has cam track portions at each end of said oblique cam track portion extending parallel to the direction of reciprocation of said cam bar.

18. in an electric circuit breaker having at least three interrupters in parallel vertical array, said interrupters each having a pair of separable contacts one of which is stationary and the other of which is axially movable into and out of engagement with said stationary contact;

operating means including a cam follower operably connected to each of said axially movable contacts for actuating all of said contacts simultaneously in the same direction into and out of engagement with their associated stationary contacts, said operating means includes contact loading compression spring means for transmitting contact closing motion of each of said cam followers to each of movable contact;

means for deflecting each of said contact loading compression spring means to a predetermined loading and for providing a positive connection between said associated cam follower and said associated movable contact when said cam follower is moved in a contact opening direction and each being adjustable to vary said predetermined loadsaid means for deflecting said contact loading compression spring means is adjustable when said pair of contacts are open to vary the predetermined loading of said contact loading compression spring means and thus change the stroke through which said contact operating means is actuated by said cam follower in a manner that the closing of said pairs of contacts of said plurality of vacuum interrupters can be synchronized at a single point in each of said movable contact operating means;

each said movable contact operating means includes an elongated, insulated, axially reciprocable contact operating rod operatively connected at one end to said movable contact, a U-shaped stirrup embracing said contact loading compression spring means and the other end of said operating rod and said cam follower and having the legs of said U- shaped stirrup coupled to said cam follower, and wherein said contact loading compression spring means reacts at one end against the cross piece of said U-shaped stirrup and at its opposite end against said other end of said operating rod;

an elongated cam bar supported for reciprocable movement in a direction transverse to the direction in which said movable contacts are movable; and,

a plurality of identical cam slots formed in said cam bar one for each movable contact, said cam slots being disposed along a common axis, said cam slots having identical configurations including a cam track portion inclined at an oblique angle to the direction of cam bar reciprocation, each cam slot also including a cam track portion at each end of said inclined portion, said cam slots each operatively receiving a cam follower.

19. An electric circuit breaker in accordance with claim 18 and including bolt means affixed at one end to said contact operating rod and extending through said contact loading compression spring means and also through a clearance hole in said cross piece of said U-shaped stirrup for deflecting said contact loading springs to a predetermined loading and for providing a positive connection between said cam follower and said contact operating rod when said cam follower is actuated in a contact opening direction and permitting relative movement therebetween when said cam follower is actuated in a contact closing direction, said bolt means being adjustable to vary the deflection of said contact loading springs and the contact closing stroke of said contact operating rod.

20. An electric circuit breaker in accordance with claim 19 wherein each said movable contact operating means includes pivoted yoke means operatively connected to said cam follower for guiding said other end of said contact operating rod in substantially straight line motion axially of said movable contact as said cam follower is actuated by said cam bar.

Claims

1. In an electric circuit breaker having at least three interrupters in parallel vertical array, said interrupters each having a pair of separable contacts one of which is stationary and the other of which is axially movable into and out of engagement with said stationary contact; opErating means including a cam follower operably connected to each of said axially movable contacts for actuating all of said contacts simultaneously in the same direction into and out of engagement with their associated stationary contacts; an elongated cam bar supported for reciprocal movement in a direction transverse to the direction in which said movable contacts are movable; a plurality of identical cam slots formed in said cam bar, one for each movable contact, said cam slots being disposed along a common axis, said cam slots having identical configurations including a cam track portion inclined at an oblique angle to the direction of cam bar reciprocation, each cam slot also including a cam track portion at each end of said inclined portion, said cam slots each operatively receiving a cam follower; a pivoted yoke for each cam follower and operatively connected to each cam follower for guiding the lower end of said contact in such a manner that in the closing movement said movable contacts move in an arcuate path of travel that terminates on a line that includes the axes of the contacts when said contacts are in closed position to thereby provide a wiping engagement between the contact faces of said contacts; and, a contact loading compression spring for each of said contacts, said loading compression spring being supported in position to provide for predetermined high pressure engagement between the movable contact and an associated stationary contact irrespective of the amount of over travel of an associated cam follower, whereby movement of said cam bar in one direction will effect simultaneous movement of all of said movable contacts in the same direction into engagement with their associated stationary contacts and upon movement of said cam bar in the opposite direction all of said movable contacts will move simultaneously in the same direction to open positions.

2. An electric circuit breaker in accordance with claim 1 wherein each of said cam followers include a roller disposed in an associated one of said cam slots and said cam bar has a plurality of guide grooves therein elongated in the direction of reciprocation of said cam bar, and wherein said circuit breaker also has means including guide grooves and guide rollers disposed in said guide grooves for guiding said cam bar in its direction of reciprocation and preventing movement thereof in all directions transverse to its direction of reciprocation.

3. In an electric circuit breaker having at least three vacuum interrupters in parallel vertical array, said interrupters each having a pair of separable contacts one of which is stationary and the other of which is axially movable into and out of engagement with said stationary contact; operating means including a cam follower operably connected to each of said axially movable contacts for actuating all of said contacts simultaneously in the same direction into and out of engagement with their associated stationary contacts, said operating means including contact loading compression spring means for transmitting contact closing motion of each of said cam followers to each of said movable contacts, and means for deflecting each of said contact loading compression spring means to a predetermined loading and for providing a positive connection between said associated cam follower and said associated movable contact when said cam follower is moved in contact opening direction and each being adjustable to vary said predetermined loading; an elongated cam bar supported for reciprocal movement in a direction transverse to the direction in which said movable contacts are movable; a plurality of identical cam slots formed in said cam bar one for each movable contact, said cam slots being disposed along a common axis, said cam slots having identical configurations including a cam track portion inclined at an oblique angle to the direction of cam bar reciprocation, each cam slot also including a cam track portion At each end of said inclined portion, said cam slots each operatively receiving a cam follower; a pivoted bell crank lever having an arm pivotally connected to said reciprocable cam bar; preloaded contact opening spring means engaging an arm of said bell crank lever and further loaded when said cam bar is reciprocated in a direction to close said contacts of said plurality of vacuum interrupters; and, latch means adapted to releasably engage an arm of said bell crank lever for holding said bell crank lever and said cam bar in a position wherein said contacts of said plurality of interrupters are closed, whereby the forces of said plurality of contact loading compression spring means and of said contact opening spring means are additive to open said plurality of vacuum interrupters.

4. An electric circuit breaker in accordance with claim 3 and including a trip solenoid provided with an armature movable when said solenoid is energized from a released position wherein said latch means can latch said bell crank lever to a trip position wherein said solenoid trips said latch means to free said bell crank lever, said armature having a portion accessible from the exterior of said trip solenoid, a pivoted switch operating handle engaging said accessible portion of said armature and being adapted to move said armature from said released position to said trip position, and spring means engaging said accessible portion of said armature for normally holding said armature in said released position and thereby preventing inadvertent opening of said vacuum switch contacts when said operating handle is engaged with a hot stick.

5. In an electric circuit breaker, in combination; a supporting base; a plurality of vacuum interrupters mounted in spaced relation on said base in a plane transverse to said base and each having a stationary contact, movable contact, and means including a cam follower for operating said movable contact into and out of engagement with said stationary contact; elongated reciprocable cam bar means having a plurality of cam slots therein each of which has a cam track portion oblique to the direction of cam reciprocation receiving one of said cam followers for simultaneously actuating said movable contact operating means of said plurality of vacuum interrupters; means affixed to said supporting base for guiding and supporting said cam bar for reciprocation in said plane transverse to said base; a mounting plate, said cam bar guiding means supporting said mounting plate in said plane transverse to said base; bell crank lever means pivoted on said mounting plate and having one arm operatively connected to said reciprocable cam bar; switch opening spring means affixed at one end to an arm of said bell crank lever means and at the other end to said mounting plate and being further loaded when said cam bar is reciprocated in the switch closing direction; latch means pivotally supported on said mounting plate for latching said bell crank lever when said cam bar is in switch closing position; and trip solenoid means affixed to said mounting plate for releasing said latch means to free said bell crank lever means when said trip solenoid is energized.

6. An electric circuit breaker in accordance with claim 5 and including a closing solenoid supported on said mounting plate and having a plunger operatively connected to an arm of said bell crank lever means for actuating said cam bar to switch closing position when said closing solenoid is energized.

7. An electric circuit breaker in accordance with claim 6 wherein said trip solenoid is provided with an armature movable when said trip solenoid is energized from a released position wherein said latch means can latch said bell crank lever means to a trip position wherein said trip solenoid armature trips said latch means to free said bell crank lever means, said trip solenoid armature having an accessible portion; a switch operating handle pivotally supported on saId mounting plate and being adapted to move said trip solenoid armature from said released position to said trip position; and, spring means engaging said accessible portion of said trip solenoid armature for normally holding said armature in said released position, thereby preventing inadvertent opening of said vacuum interrupter contacts when said operating handle is engaged with a hot stick.

8. An electric circuit breaker in accordance with claim 5 wherein said cam bar guiding and supporting means includes a plurality of aligned pairs of cam guide legs projecting from the side of said supporting base opposite that on which said vacuum interrupters are mounted and with the legs of each said pair being spaced apart and disposed on opposite sides of a plane transverse to said base and of said cam bar and affixed adjacent their ends to said mounting plate.

9. An electric circuit breaker in accordance with claim 8 wherein said cam bar has a plurality of cam grooves therein elongated in the direction of cam bar reciprocation each of which is adjacent one of said pairs of cam guide legs, and said cam bar guiding and supporting means includes said cam grooves, a roller in each of said cam grooves, and a roller support member extending through each said pair of cam guide legs and revolvably supporting one of said rollers with the corresponding cam groove.

12. In an electric circuit breaker having at least three interrupters in parallel vertical array, said interrupters each having a pair of separable contacts one of which is stationary and the other of which is axially movable into and out of engagement with said stationary contact; operating means including a cam follower operably connected to each of said axially movable contacts for actuating all of said contacts simultaneously in the same direction into and out of engagement with their associated stationary contacts; an elongated cam bar supported for reciprocal movement in a direction transverse to the direction in which said movable contacts are movable; a plurality of identical cam slots formed in said cam bar one for each movable contact, said cam slots being disposed along a common axis, said cam slots having identical configurations including a cam track portion inclined at a oblique angle to the direction of cam bar reciprocation, each slot also including a cam track portion at each end of said inclined portion, said cam slots each operatively receiving a cam follower; an elongated, longitudinally reciprocable, insulated contact operating rod for each axially movable contact, said operating rods being operatively connected to an adjacent end of an associated movable contact; precompressed contact loading compression spring means for transmitting switch closing cam follower motion to the other end of each of said contact rods; a U-shaped stirrup bracketing each of said cam followers and an associated contact operating rod, each of said U-shaped stirrups having the legs thereof operatively coupled to an associated cam follower, said contact loading compression spring means being adapted to react at its opposite ends against the cross piece of said U-shaped stirrup and against said other end of said associated contact operating rod; adjustable bolt means affixed to said other end of each of said contact operating rods for precompressing said contact loading compression spring means against the cross piece of said U-shaped stirrup and for varying the stroke of said contact operating rod resulting from switch closing motion of said cam follower; and, a pivoted member for each of said cam followers operatively connected to an adjacent end of an associated insulated contact operating rod for guiding the movement of the adjacent lower end of an associated movable contact in an arcuate path of travel that terminates on a line that includes the axes of said contacts when said contacts are in closed position to thereby provide a wiping engagement between the contact faces of said contacts.

13. In an electric circuit breaker having at least three vacuum interrupters in parallel vertical array, said interrupters each having a pair of separable contacts one of which is stationary and the other of which is axially movable into and out of engagement with said stationary contact; operating means including a cam follower operably connected to each of said axially movable contacts for actuating all of said contacts simultaneously in the same direction into an out of engagement with their associated stationary contacts; an elongated cam bar supported for reciprocal movement in a direction transverse to the direction in which said movable contacts are movable; a plurality of identical cam slots formed in said cam bar one for each movable contact, said cam slots being disposed along a common axis, said cam slots having identical configurations including a cam truck portion inclined at an oblique angle to the direction of cam bar reciprocation, each cam slot also including a cam track portion at each end of said inclined portion, said cam slots each operatively receiving a cam follower; an elongated, longitudinally reciprocable, insulated contact operating rod for each axially movable contact, said operating rods being operatively connected to an adjacent end of an associated movable contact; precompressed contact loading compression spring means for transmitting switch closing cam follower motion to the other end of each of said contact rods; a U-shaped stirrup bracketing each of said cam followers and said other end of an associated contact operating rod; individual bolt means extending through the legs of each of said stirrups and through said associated cam follower for coupling said stirrups to said cam followers, wherein said contact loading compression spring means react at one end against the cross piece of associated stirrups and at the opposite end against said other end of an associated contact operating rod; individual bolt means affixed to said other end of each of said contact operating rods and extending through an associated contact loading compression spring means and through a clearance aperture in the cross piece of an associated stirrup for adjusting the position of said operating rod relative to the cross piece of its associated U-shaped stirrup to thereby provide means for varying the preloading of said contact loading compression spring means and the stroke of said contact operating rod as desired; and, a pivoted member for each of said insulated contact operating rod operatively connected to an adjacent end of an associated cam follower for guiding the movement of the adjacent lower end of an associated movable contact in an accurate path of travel that terminates on a line that includes the axes of said contacts when said contacts are in closed position to thereby provide a wiping engagement between the contact faces of said contacts.

14. In an electric circuit breaker, in combination; a supporting base; a plurality of vacuum interrupters mounted in spaced relation on said base in a plane transverse to said base and each having a stationary contact, a mOvable contact, and means including a cam follower for operating said movable contact into and out of engagement with said stationary contact; elongated reciprocable cam bar means having a plurality of cam slots therein each of which has a cam track portion oblique to the direction of cam reciprocation receiving one of said cam followers for simultaneously actuating said movable contact operating means of said plurality of vacuum interrupters; means affixed to said supporting base for guiding and supporting said cam bar for reciprocation in said plane transverse to said base; a mounting plate, said cam bar guiding means supporting said mounting plate in said plane transverse to said base; bell crank lever means pivoted on said mounting plate and having one arm operatively connected to said reciprocable cam bar; switch opening spring means affixed at one end to an arm of said bell crank lever means and at the other end to said mounting plate and being further loaded when said cam bar is reciprocated in the switch closing direction; latch means pivotally supported on said mounting plate for latching said bell crank lever when said cam bar is in switch closing position; trip solenoid means affixed to said mounting plate for releasing said latch means to free said bell crank lever means when said trip solenoid is energized, said trip solenoid being provided with an armature movable when said trip solenoid is energized from a released position wherein said latch means can latch said bell crank lever means to a trip position wherein said trip solenoid armature trips said latch means to free said bell crank lever means, said trip solenoid armature having an accessible portion; a switch operating handle pivotally supported on said mounting plate and being adapted to move said trip solenoid armature from said released position to said trip position, said switch operating handle having a lever arm operatively connected to said cam bar, wherein manual operation of said handle in one direction reciprocates said cam bar to switch closing position and operation thereof in the opposite direction actuates said trip solenoid armature to said trip position to release said latch means; spring means engaging said accessible portion of said trip solenoid armature for normally holding said armature in said released position, thereby preventing inadvertent opening of said vacuum interrupter contacts when said operating handle is engaged with a hot stick; and, a closing solenoid supported on said mounting plate and having a plunger operatively connected to an arm of said bell crank lever means for actuating said cam bar to switch closing position when said closing solenoid is energized.

15. In an electric circuit breaker, in combination; a supporting base; a plurality of vacuum interrupters mounted in spaced relation on said base in a plane transverse to said base and each having a stationary contact, a movable contact, and means including a cam follower for operating said movable contact into and out of engagement with said stationary contact, each said movable contact operating means includes yoke means pivotally mounted at one end on one of said roller support members and operatively connected at the other end to one of said cam followers for guiding said movable contact in essentially straight line axial motion as it is actuated between open and closed positions, each said movable contact operating means also includes an elongated, longitudinally reciprocable, insulated contact operating rod operatively connected at one end to the associated movable contact and precompressed contact loading compression spring means for transmitting switch closing cam follower motion to the other end of said contact operating rod; each said movable contact operating means also includes a U-shaped stirrup bracketing said contact loading compression spring means and having the legs thereof operatively connected to said cam follower, and wherein Said contact loading spring means react at one end against the cross piece of said U-shaped stirrup and at the opposite end against said other end of said contact operating rod; elongated reciprocable cam bar means having a plurality of cam slots therein each of which has a cam track portion oblique to the direction of cam reciprocation receiving one of said cam followers for simultaneously actuating said movable contact operating means of said plurality of vacuum interrupters; means affixed to said supporting base for guiding and supporting said cam for reciprocation in the plane transverse to said base; said cam bar guiding and supporting means includes a plurality of aligned pairs of cam guide legs projecting from the side of said supporting base opposite that on which said vacuum interrupters are mounted and with the legs of each said pair being spaced apart and disposed on opposite sides of the plane transverse to said base and of said cam bar and affixed adajcent their ends to said mounting plate; said cam bar has a plurality of cam grooves therein elongated in the direction of cam bar reciprocation each of which is adjacent one of said pairs of cam guide legs, said cam bar guiding and supporting means includes said cam grooves, a roller in each of said cam grooves, and a roller support member extending through each said pair of cam guide legs and revolvably supporting one of said rollers within the corresponding cam groove; a mounting plate, said cam bar guiding means supporting said mounting plate in the plate transverse to said base; bell crank lever means pivoted on said mounting plate and having one arm operatively connected to said reciprocable cam bar; switch opening spring means affixed at one end to an arm of said bell crank lever means and at the other end to said mounting plate and being further loaded when said cam bar is reciprocated in the switch closing direction; latch means pivotally supported on said mounting plate for latching said bell crank lever when said cam bar is in switch closing position; and, a trip solenoid affixed to said mounting plate for releasing said latch means to free said bell crank lever means when said trip solenoid is energized.

17. An electric circuit breaker in accordance with claim 16 wherein each said cam slot in said cam bar also has cam track portions at each end of said oblique cam track portion extending parallel to the direction of reciprocation of said cam bar.

18. In an electric circuit breaker having at least three interrupters in parallel vertical array, said interrupters each having a pair of separable contacts one of which is stationary and the other of which is axially movable into and out of engagement with said stationary contact; operating means including a cam follower operably connected to each of said axially movable contacts for actuating all of said contacts simultaneously in the same direction into and out of engagement with their associated stationary contacts, said operating means includes contact loading compression spring means for transmitting contact closing motion of each of said cam followers to each of movable contact; means for deflecting each of said contact loading compression spring means to a predetermined loading and for providing a positive connection between said associated cam follower and said associated movable contact when said cam follower is moved in a contact opening direction and each being adjustable to vary said predetermined loading; said means for deflecting said contact loading compression spring means is adjustable when said pair of contacts are open to vary the predetermined loading of said contact loading compression spring means and thus change the stroke through which said contact operating means is actuated by said cam follower in a manner that the closing of said pairs of contacts of said plurality of vacuum interrupters can be synchronized at a single point in each of said movable contact operating means; each said movable contact operating means includes an elongated, insulated, axially reciprocable contact operating rod operatively connected at one end to said movable contact, a U-shaped stirrup embracing said contact loading compression spring means and the other end of said operating rod and said cam follower and having the legs of said U-shaped stirrup coupled to said cam follower, and wherein said contact loading compression spring means reacts at one end against the cross piece of said U-shaped stirrup and at its opposite end against said other end of said operating rod; an elongated cam bar supported for reciprocable movement in a direction transverse to the direction in which said movable contacts are movable; and, a plurality of identical cam slots formed in said cam bar one for each movable contact, said cam slots being disposed along a common axis, said cam slots having identical configurations including a cam track portion inclined at an oblique angle to the direction of cam bar reciprocation, each cam slot also including a cam track portion at each end of said inclined portion, said cam slots each operatively receiving a cam follower.