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Publication numberUS3749873 A
Publication typeGrant
Publication date31 Jul 1973
Filing date18 Aug 1971
Priority date18 Aug 1971
Publication numberUS 3749873 A, US 3749873A, US-A-3749873, US3749873 A, US3749873A
InventorsHarper G, Shand J
Original AssigneeAirpax Electronics
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Circuit breaker housing
US 3749873 A
Disclosed is an electrical circuit breaker having an improved case construction. The case comprises three principal elements made of suitable thermoplastic and snapped together without separate fasteners or adhesive, namely, a rocker actuator, a housing, and a base. The actuator may be provided with a light and one or more of the plastic elements may be suitably colored. A removable auxiliary terminal plug is provided in the base and the terminals are retained by turned-over tabs after insertion.
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Description  (OCR text may contain errors)

United States Patent 11 1 I Harper et al.

[11] 3,749,873 14 1 July 31,1973

1 CIRCUIT BREAKER uousinc [75] inventors: George S. Harper, Cambridge; John Richard Shand, Easton, both of Md.

[7 3] Assignee: Airpax Electronics Incorporated,

Cambridge, Md.

[22] Filed: Aug. 18, 1971 [21] Appl. No.: 172,632

[52] U.S. Cl. 200/168 R, 335/202 [51] Int. Cl. H0111 9/02 [58] Field of Search 200/172 R,l72 A, 200/153 T, 166 CT, 168 C, 167 A, 168 R; 335/64, 202

[56] References Cited UNITED STATES PATENTS 3,626,338 12/1971 Nicol et al. 335/202 3,609,268 9/1971 Sanchez 200/167 A 3,103,570

9/1963 Gibbs .1 2001172 A 3,466,413 9/1969 Sharples ZOO/168 C Primary Examiner-Herman J. l-lohauser 9 Assistant Examiner-William J. Smith Attorney-LeBlanc & Shut [57] ABSTRACT Disclosed is an electrical circuit breaker having an improved case construction. The case comprises three principal elements made of suitable thermoplastic and snapped together without separate fasteners or adhesive, namely, a rocker actuator, a housing, and a base. The actuator may be provided with a light and one or more of the plastic elements may be suitably colored. A removable auxiliary terminal plug is provided in the base and the terminals are retained by turned-over tabs after insertion. v

5 Claims, 9 Drawing Figures PATENIEDJULS H975 3'749'873 sum 1 0r 2 INVENTORS. GEORGE S. HARPER J. RICHARD SHAND BY jl v'e, a f


'Pmmniuwm 3,749,873 4 SHEET 2 BF 2 FIG. 6 FIG] I00 -E/QB 'l 9 i 24 24 4 r 1' .FIG.9 n2 fi uz INVENTORS & GEORGE s. HARPER J. RICHARD SHAND ATTORNEYS.

CIRCUIT BREAKER HOUSING 1 This invention relates to electrical circuit breakers and more particularly to an improved circuit breaker housing for electromagnetic circuit breakers.

Electromagnetic circuit breakers have been used for many years to interrupt and protect a variety of electrical circuits. These breakers generally comprise an overcurrent coil wrapped around a magnetic core, ei-

ther with or without a hydraulic time delay tube. A contact bar carrying a movable contact is actuated by a manually operated handle through a collapsible toggle to move the contact between the open and closed positions. The toggle is conventionally provided with a trip mechanism engaged by an armature adjacent the overcurrent coil so that an overload current through the coil attracts the armature, consequentially tripping the toggle which collapses to open the contacts automatically. The circuit breakers may be single pole or multiple pole devices in which latter case individual poles of the multipole unit are often interconnected either through the handles or by an internal mechanism such as a comonon trip bar.

In the past, circuit breakers have been largely considered purely utilitarian and used only as protective devices. The breakers are customarily made of a black electrically insulating material, such as phenolic, with little consideration being given to the breaker appearance. 1

The present invention is directed to an improved breaker construction and more particularly 'to an improved breaker case having a more pleasing appareance so that the aesthetic qualities of the breaker are improved when it is placed for viewing on the front panel of electrical equipment. Thebreaker canserve as a protective device, an on-off switch, and a pilot light. Through the use of an improved assembly technique and improved case materials, it is possible to provide the case in various colors and color combinations for improved appearance. In addition, the new materials make possible economies in manufacture.

The circuit breaker case is formed essentially of three separate parts which are assembled by snapping them together without the use of rivets or the like. The lower case section telescopes within the upper case section and because of the resiliency of the plastic materials from which the case may be made, these two sections are snapped together. The third principal component of the case, also made of plastic, is the manual actuator which is also snapped into the upper or front portion of the case. Addtional features include an optional snapin or flush mounting construction for the panel in which the circuit breaker is placed, as well as an illuminated handle and an improved arrangement for holding a plug in the lower case section as well as an improved terminal assembly. The circuit breaker may be provided in eitherone pole or multipole versions with single rocker actuation. The snap-together-assembly elirne inates the need for rivets, epoxy, or the like, and the plastic materials used make possible improved panel appearance through the selection of appropriate colors or color combinations. The breaker can be used as an on-off switch, control device, manually reset relay, and pilot light, in addition to circuit breaker protection.

It is therefore one object of the present invention to provide an improved electrical circuit breaker.

Another object of the present invention is to provide an improved electrical circuit breaker case.

and the like.

Another object of the present invention is to provide an improved circuit breaker construction having a novel snap-in manual actuator.

Another object of the present invention is to provide a circuit breaker having an improved plug and terminal mounting construction.

These and further objects and advantages of the invention will be more apparent upon reference to the following specification, claims, and appended drawings, wherein: l

FIG. 1 is an exploded view of an electromagnetic circuit breaker case constructed in accordance with the present invention; i

FIG. 2 is aside view 'of the assembled case with portions broken away for the sake of clarity;

FIG. 3 is a partial cross section-through the circuit breaker case taken along line 3-3 of FIG. 2;

FIG. 4 shows an electromagnetic circuit breaker having acase constructed in accordance'withFIGS. 1-3 snap-mounted into a circuit breaker panel;

FIG. 5 shows the circuit breaker of the present invention flush mounted to a circuit breaker panel;

' FIG. 6 shows a multipole or two-pole circuit breaker constructed in accordance with the present invention;

FIG. 7 is an inside plan view showing the base-of the circuit breaker casing of the present invention provided with an auxiliary switch plug;

FIG. 8 is a cross section taken along line 8-8 of FIG. 7; and I FIG. 9 is a cross section taken at right angles to that of FIG. 8 along line 9-9 of FIG. 7.

Referring to the drawings, the novel circuit breaker of the present invention is generally indicated at 10 in FIGS. 4 and 5 and comprises a circuit breaker housing 12, shown in exploded view in FIG. 1, and comprising three sections, namely, a lower section or base 14, an upper section or housing 16, and a snap-in manual actuator 18. The inner operating mechanisms of the circuit breaker are not shown and these maybe of conventional constructions,such as those shown by way of example only'in'assignee's U.S. Pat. Nos. 3,412,351;

r 3,444,488 and 3,497,838, the disclosures of which are incorporated herein by reference.

' j Base :14 of the circuit breaker case is provided with a pair of electrical terminals 20 and 22 in a manner more fully described below. Base 14 is otherwise made of plastic and is formedwith four integral projections 24, one on each side of the base. Housing 16 is similarly moldedof plastic and includesan upper boss 26 and a collar 28 from which depends the hollow rectangular body 30 which forms the major portion of the circuit breaker casing and which houses the operating mechanism of the electromagnetic circuit breaker. Body 30 is provided with four small rectangular apertures 32 located to receive the base projections 24 when the base 14 and housing 16 are snapped together.

Received in the top of housing 16 is a manual actuator 18 of generally U-shaped cros section. The actuator comprises a pair of symmetrical handles 34 and 36 forming a rocker and from which depend a pair of spaced legs 38 and 40. Each of these legs is similarly bifurcated to provide slots 42 which receive a toggle actuator bar 44 (FIG. 3) carried by a toggle link 46. Each of the spaced legs 38 and 40 is also provided on its external surface with a L-shaped groove 48 adapted to slidably receive a corresponding one of the nubs "or projections 50 and 52 projecting inwardly from the boss 26. The inner end of each groove at 54 forms a semicylindrical bearing such that the actuator pivots with the end of each groove engaging one of the nubs 50 and 52. If desired, a small light source, as indicated by the bulb 58, may be secured to a small plastic shelf (not shown) supported by the breaker frame between the legs 38 and 40 to illuminate the handle portions 34 and 36 of the actuator. Finally, body 16 is preferably provided with a pair of integral flexible wings 60 and 62, preferably having roughened or serrated end surfaces 64 to provide a snap-in mounting as more fully described below.

During assembly, the actuator 18 is first moved in the direction of the arrow 66 in FIG. 1 so that the nubs 50 and 52 are received in the L-shaped grooves 48 and 50 formed in the outer surfaces of the actuator legs 38 and 40. The actuator is inserted and then rotated into the position illustrated in FIG. 2 with the semicylindrical bearings rotating about the semicylindrically shaped nubs 50. The operating mechanism of the breaker (not shown) is then inserted into the housing 12 so that the actuator bar 44 is received in the slots 42 in the actuator. With the bar received in the actuator leg slots, the actuator is securely retained or restrained by the operating mechanism ofthe circuit breaker and namely the bar 44 so that it cannot be removed. By depressing first handle 34 and then handle 36 in FIG.2, the actuator is rocked back and forth'about the pivot axis'form'ed by the nubs 50 and actuator bar 44 is correspondingly rocked back and forth to open and close the circuit breaker contacts. Finally, base 14 is moved upwardly in the direction of the arrow 68 in FIG. 1 where it is telescopically received within the lower end of body 30 until the projections 24 snap into the apertures 32 tightly locking the circuit breaker and case assembly together. Once the elements l4, l6, and 18 in FIG. 1 have been assembled, they cannot be readily disengaged without destroying the circuit breaker case.

FIG. 4 shows a snap-in mounting provided by the wings 60 and 62. The circuit breaker is shown mounted on a circuit breaker panel 70 having a rectangular aperture 72. Aperture 72 is slightly larger than the body 30 of the case but is smaller than the collar 28. The circuit breaker is inserted through aperture 72 and the flexible wings 60 and 62 compress and pass through the aperture. The circuit breaker is inserted untilthe collar 28 engages circuit breaker panel 70, at which time the resilient wings 60 and 62 flex outwardly so that their roughened surfaces 64 engage the rear edge of the aperture 72, tightly holding and locking the circuit breaker to the panel.

FIG. shows a flush mounting construction in which a circuit breaker panel 72 is apertured to receive a pair of screws 74 and 76. These screws are threaded into the longer leg of a pair of L-shaped brackets 78 and 80, the shorter legs engaging the back of the panel 72 and the longer legs are clamped by the screws 74 and 76 against the underside of the collar 28. Again, the flexibility of the wings 60 and 62 permit insertion of the brackets 78 and 80 beneath collar 28.

FIG. 6 shows a multipole circuit breaker constructed in accordance with the present invention. The'circuit breaker is provided with a single rocker actuator 18, in all respects identical to the actuator previously described. In FIG. 6, the circuit breaker is a multipole breaker and the housing 16' is provided with six instead of-four apertures, two of which are illustrated at 84 inv FIG. 6, which receivecorresponding projections on the base 14'. Except for the size and number of interlocking projections and apertures, the case illustrated in FIG. 6 is identical to that previously described. The respective poles of the circuit breaker mechanism are interconnected by suitably extending actuator bar 44 so that it is common to the two toggle links, i.e., one for each pole, corresponding to the toggle link 46 in FIG.

FIG. 7 is a plan view of a modified -base similar to the base 14 previously described but provided with a plug 92 and auxiliary terminals 94 and 96 for an auxiliary switch. The auxiliary switch adapted to be mounted in plug 92 is omitted for the sake of clarity but may be of conventional construction, as shown byway of example only in assignees U.S. Pat. No. 3,501,606, which is incorporated herein by reference. Also shown in FIG. 7 are the two spaced legs 98 and I00 of a metal frame 102 on which the operating mechanism of the circuit breaker is mounted. Base 90 is provided with a stationary contact 104 adapted tobe" engaged by the movable contact of the circuit breaker mechanism and this stationary contact 104 is electrically connected in a conventional manner to terminal 22. The other main terminal 20' is adapted to be connected to the'overcurrent coil 'of the mechanism in a conventional manner. Each of these terminals, such as the tenninal 20, is stamped from flat electrically conductive metal stock and is provided with lateral extensions approximately midway of its ends which are slotted so that when the terminal has been inserted throughasuitable aperture in the base 90, these slotted tabs integral with the terminals are turned over as at 106 and 108 to tightlylock the terminal in position so that it extends from the interior of the base outwardly for connection'to an external circuit to be protected. Plug 92 is removable and-is inserted into a suitable aperture which remains whena knock-out portion of the base 90 is removed. The plug 92 fits in the aperture 1 l0 and is provided with a flange at its upper edge as illustrated at 112 which extends outwardly to overlie the adjacent surface of base 90. Plug 92 is inserted into aperture 112 with the flange overlying the base and the-flange 112 is heldin place by the legs and 98 of the'frame which rest on top of the flange 112 as illustrated in FIG. 9. Terminals 94 and 96 may be formed with turned-over portions on each side of theplug in the manner of the terminals 20 or22 or, alternatively, terminals 94.and 96 may be provided with lateral extensions or shoulders 114. and l 16, as illustrated in FIG. 9, on the outer side of the plug. The inner ends are turned over as illustrated at 118 and 120 in FIG. 8. j I

It is apparent from the above that the present invention provides an improved electromagnetic circuitbreaker and in particular an improved circuit breaker case which greatly increases the ease and economy of assembly of the circuit breaker. Through the utilization of plastic materials exhibiting a limited amount of resilience, it is possible to snap the base into the circuit breaker housing and through the provision of flats on nubs 50 the actuator may be attached to the case without any need for rivets, adhesives, epoxy, or the like. The plastic materials make possible a wide variety of colors wherein each of the elements 14, 16, and 18 is of either thesame or different colors to provide different color combinations. in the preferred embodiment, the circuit breaker case is made of all thermoplastic materials and, by way of example only, the housing 16 and actuator 18 may be molded from a polycarbonate, identified as Lexan 141, manufactured by the General Electric Company. This provides a strong material which is available in a variety of colors. By way of example only, the base 14 and the corresponding bases 14' and 90 are preferably formed from a high temperature distortion plastic such as polysulfone, identified as Pl700 as manufactured by Union Carbide Corporation. It is understood that other plastic materials may be utilized where desired but the above'provide excep} tional color characteristics in the polycarbonate in combination with a base material that has a higher temperature distortion point in the electrical contact area.

By providing a snap-in actuator 'l 18 with the spaced legs, it is possible to mount an incandescent or neon bulb 58 between the moving legs of the actuator handle. This provide full handle illumination without bulb movement and the associated problems of wire flexing. While the plug 92 has been described in conjunction with the use of an auxiliary switch, it is understood that the plug may be used in any situation in which two additional terminals are required. The plug is retained solely by the bottom of the circuit breaker base and the frame 102. The terminals are held into the circuit breaker base by the tabs illustrated which are folded over after terminal insertion.

Theactuator 18 is inserted into housing 16 with the nubs 50 passing through the L-shaped slot 48 to the slot ends 54. This insertion is made possible by providing a small flat 122 on each of the otherwise cylindrical nubs 50 and 52 so that they may be readily inserted into the ends of the grooves 48. After the actuator has been lowered and rotated into the operating position illustrated in FIG. 2,'it is locked into the housing 16 by re- J therefore intended to be .embraced therein.

ceipt of the actuator bar 44 into the slots 42 and excessive rotational motion of the actuator 18 is prevented by the bar 44 and the operating mechanism of the circuit breaker toggle.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are What is claimed and desired to be'se'cured by Un' States Letters Patent is:

1. In an electromagnetic circuit breaker, a case comprising a thermoplastic housing, a thermoplastic base, resilient fastening means on said base and said housing joining them together, a toggle bar in said case, and a rocker actuator pivoted to said housing, said actuator having inner ends engaging said toggle bar, said base being provided with a pair of main terminals and an aperture between. said terminals,a nd a plug extending throughsaid aperture and having a flange overlying the inner surface of said base.

2. A circuit breaker according to claim 1 including a frame in said case, said plug flange being clamped between said frame and the interior surface-of said base.

3. In an electromagnetic circuit breaker, a case comprising a thermoplastic housing, a thermoplastic base,

' a resilient fastening means on said base and housing joining them together, a toggle bar in said case, a rocker actuator pivoted to said housing, said actuator having its inner end engaging said toggle bar, said actuator comprising a pair of handle portions joined to a pair of spaced legs, the ends of said legs having slots receiving said toggle'bar, and including a pair of projections on said housing, said actuator including L-shaped grooves slidably receiving said projections.

4. A circuit breaker according to claim 3 wherei said projections are semicylindrical with flats on one side.

-5. Acircuit breaker according to claim 3 wherein said grooves have first portions extending from said housing projections toward said slots, and second per-. pendicular portions terminating at a side edge of said legs.

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U.S. Classification200/293, 335/202, 220/3.6
International ClassificationH01H71/02
Cooperative ClassificationH01H71/0214, H01H71/0264
European ClassificationH01H71/02D, H01H71/02B1