US3590194A

US3590194A - Contact- and circuit-mounting board for trigger-operated switch unit

Info

Publication number: US3590194A
Application number: US859277A
Authority: US
Inventors: Carl J Frenzel; Alex F Gawron
Original assignee: Skil Corp
Current assignee: Skil Corp
Priority date: 1969-09-19
Filing date: 1969-09-19
Publication date: 1971-06-29
Anticipated expiration: 1988-06-29
Also published as: NL7013709A; CA922775A; FR2062268A5; DE2046232A1; GB1290770A

Abstract

A contact- and circuit-mounting board of unitary construction is contained within the housing of the switch unit. This board mounts fixed contacts which cooperate with other contacts carried by a reversing lever mounted adjacent the trigger. This board also mounts contact strips which are slidably engaged by contact fingers carried by the trigger thereby to define an on-off switch, a bypass switch and a variable resistor forming part of a speed control circuit. The elements of the circuit are contained on a printed circuit board, the latter being secured to the mounting board.

Description

i United States Patent [72] lnventors Carl]. Frenzel; 3,260,827 7/1966 Frenzel 200/157 Alex F. Gawron. both of Chicago, 111. 2,942,087 6/1960 Meuer 200/157 [21] Appl. No. 859,277 3,484,632 12/1969 Opalenik et al..." 200/157 X [22} Filed Sept. 19,1969 3,327,196 6/1967 Sahrbacker 318/345 [451 Patented June 29,1971 3,447,057 5/1969 Brown et a1 318/345 [73] Assignee Corpomuon Primary Examiner-D. F Duggan Chlcago Assirtant ExaminerB. A. Reynolds Attorney-McDougall, Hersh & Scott [54] CONTACT- AND CIRCUIT-MOUNTING BOARD FOR TRIGGER-OPERATED SWITCH UNIT u Chums 6 Drawing Figs ABSTRACT: A contactand circuit-mounting board of unita- [52] US. Cl 200/157, Construction is contained within the housing of the switch 318/345 unit. This board mounts fixed contacts which cooperate with [51] int. Cl HOlh 13/08 other contacts carried by a reversing [ever mounted adjacent [50] Field of Search ZOO/157; the trigger This board also mounts Contact Strips which are 318/345; 310/50 slidably engaged by contact fingers carried by the trigger References Cited thereby to define an on-off switch, a bypass switch and a ariable resistor forming part of a speed control circuit. The ele- UNITED STATES PATENTS I ments of the circuit are contained on a printed circuit board, 3,439,248 4/1969 Winchester et al 318/331 the latter being secured to the mounting board.

PATENTEUJummn 3,590,194

IN VE N TORS CARL J. F RENZEL ALEX I-T GAWRON wwqg w YS.

PATENTEB -limes I921 3,590,194

INVENTORS CARL J. FRENZEL ATT'Ys CONTACT- AND CIRCUIT-MOUNTING BOARD FOR TRIGGER-OPERATED SWITCH UNIT OBJECTS OF THE INVENTION A primary object of the present invention is the provision of a new and improved contact and circuit-mounting board for a trigger-operated speed control switch or the like. I

Another object of the invention is the provision ofa mounting board of the type described wherein such board supports first and second contact means cooperating respectively with third and fourth contact means, the latter being carried by a reversing lever and the trigger, respectively. I

Still another object of the present invention is the provision of a mounting board of the type described, wherein such mounting board includes contact strips arranged to be slidably engaged by contact fingers carried by the trigger, one of such fingers and oneof such strips defining a variable resistor forming part ofa speed control circuit.

Another object of the present invention is the provision of a new and improved mounting board according to the foregoing object, wherein a printed circuit board is secured to such mounting board, the printed circuit board carrying the contact strip which defines the variable resistor as well as the various circuit elements defining the speed control circuit.

These and other objects and advantages of the invention will become apparent from the following specification disclosing a preferred embodiment shown in the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. I is a side elevational view ofa trigger-operated switch unit embodying the present invention, with an outer housing member being removed to expose one side ofthe unitary contact and circuit mounting board;

FIG.-2 is a side elevational view similar to FIG. I with the mounting board being removed to expose the contacts carried I by the reversing lever and the trigger;

DESCRIPTION OF A PREFERRED EMBODIMENT Referring particularly to FIG. 2, the trigger-operated switch unit of the present invention includes a housing member. generally designated 10, which has a sidewall 11, front and

rear walls

12 and 14, respectively, and top and bottom walls 15 and 16, respectively. This housing member includes an elongated guideway 18 slidably receiving a reversing lever or bar I9 of the type disclosed and claimed in Frenzel US. Pat. No. 3,260,827; it will be understood the reversing lever is slidably mounted for reciprocal movement longitudinally thereof.

The reversing lever mounts a pair of

contact balls

21, 22. As noted in FIG. 3, the contact ball 21 is engaged by a spring 23, the latter being received in a blind bore formed in one side of the reversing lever 19. This spring urges the ball 21 into engagement with fixed contacts as will be explained hereinbelow. It will be understood that the mounting for the contact ball 22 is identical to thatjust described for the contact 21.

The housing includes a cavity 25, a portion of whichdefines a guideway 26 for slidably receiving the stem of a trigger 28. The trigger includes a blind bore 29 (FIG. 4) receiving a coil spring 30, one end of which spring receives a pin-31. This pin is secured to the rear wall 14 of the housing '3. The spring 30 acts to urge the trigger to its fully extended 3, this board is secured to the housing member position, Abutting engagement of trigger surface 32 with housing wall surface 320 serves as a stop to limit outward movement of the trigger.

The trigger may be provided with adjustable stop and lock means as disclosed and claimed in Frenzel US. Pat No. 3,309,484. To this end, the trigger mounts an adjustment knob or button 33 which rotates a screw (not shown) in threading engagement with a lug 34 for moving the latter longitudinally of the trigger stem and relative thereto. This lug, which is ar ranged to abut stop means (not shown), acts as an adjustable stop to define the length of the trigger stroke. This lug also includes a latch surface 34a adapted to be engaged by the locking pin 35 (FIG. 4) so as to lock the trigger in any of its I fullydepressed positions. A locking button 36 is locking pin 35 and a coil spring 37 is provided locking button to its outermost position.

secured to the for urging the The trigger 28 carries a contact, generally designated 40,

which contact includes three

contact fingers

41, 42 and 43. As will be explained herein, these contact fingers engage fixed contacts supported by the mounting board which forms part of the present invention. As noted in Flg. 4, the contact 40 is received within a slot 44 formed in the trigger stem. The tension of the contact fingers is such that the latter, by reason of their engagement with the fixed contacts to be referred to hereinbelow, serve to retain the contact 40 in slot 44 without the aid of fastening means.

The unitary contact and circuit mounting board of the present invention is generally designated 45. As noted in FIG. 10 and forms with the latter a closed housing space. Referring to FIG. 5, the mounting board 45 supports a horizontal row of equally spaced contacts 4650. Different pairs of these contacts are engaged by the

contact balls

21, 22 in response to movement of the reversing lever 19 as will be explained below.

The mounting board 45 further supports a first contact strip 52, another contact strip 53, and acontact button 54. It will be understood that the contact finger 41 is arranged for wiping engagement with the contact strip 52 and that the contact finger 42 is arranged for sliding or wiping engagement with the contact strip 53. When the trigger is fully depressed, the finger 42 separates from the strip 53 and comes into engagement with the contact button 54,

A printed circuit board, generally designated 57, is secured, as by means of an adhesive, to the mounting board 45. This circuit board is preferably of the type disclosed and claimed in the copending application of Conrad D. Robertson, Ser. No. 845,3 l7, filed July 28, I969, Case No. 690,503. To this end, the circuit board 57 supports a contact strip 58 formed of resistance material; this strip is engaged by the contact finger 43 and cooperates with the latter to define a variable resistor.

.-The circuit board 57 also mounts (FIG. 6) a fixed resistor 59,

an unencapsulated capacitor 60, a chip-type diode 61, a chip type trigger device 62 and a chip-type semiconductor 63, such as a silicon controlled rectifier.

Reference should be had to the aforesaid Robertson application for a more detailed description of the electronic components on the circuit board 57 and the manner in which they are electrically connected. Preferably, the electronic elements on such board define a nonfeedback type of speed control system as disclosed and claimed in Gawron US. Pat. No. 3,209,228.

As shown in FIG. 6, the trigger-actuated switch is connected with a suitable motor of the reversible type having respective armature and

field windings

65 and 66. The switch unit, when I "When-the reversing lever l9.is in its aforesaid Gawron' patent. 'Whenfthe trigger reaches its fully .iepressed position, the contact finger 42 separates from the V contact strip53 and comes into engagement with the contact button 54 thereby bypassing the speed control system and energizing the motor directly from line current to operate the motorat maximum speed. V

J forward position, the contact ball, 21' engages

contacts

46, 47 and the conta c't ball fsystem. As the trigger is continued. robe dcpre'ssedAhe re- I, sistance is changed due to the sliding engagement of the contact finger 43 on the resistance strip 58, thereby increasing the 'speedof the tool'motor as is merc fully explained infthe ZZ engagescontact buttons, 49. This will establish a vcu'r- 7 i a. rcntpath through the'field windihgs 66 in one direction which V maybe considered as the forward direction of rotation for't he I. motor. When thelreversing bar. 19 .is depress'edijthecontact g bail 21f establishes a current

pathbetween contacts

47, 48 and i. 1 the contactball 22 establishes a currcntpath between the con tact buttons 49. 50. As is readily p from z o will festablish a current flow through-the field windingsof the hrnotor in theopp ositc direction thcrcbfyto rotatcithe latterin a reversedirection.

7 To prevent damage to the motor. it is desirable that the reversing lever be actuated only whenthc trigger is in its fully extended or "offv' position to this end, the reversing lever 19 is provideld with apair of recesses 70. 71in the undersideqthe'reofQ A jlocklng ball-73 is received'in'a cavity 74 in'the trigger whenthe lattcr is in its i'ully extended position. The, the;trlg ger is:depressedf, thiscamrning surface75 comes'int'o' aengagementiwithuthe,lockingball-73 and urges thejlatter upi wiirdly into. engagement with either ,thcfrecessf70 'or 71, de-

recess 74' in .the trigger sadjoinsa cammlng surfsce 75. When pending'on which recess is positioned over the ball :73. when the reversing lever bar 19 is in its innermost or reversed posi- .ticmthe' recess 'ltl is disposedover thelociging ball 13. When rsing lever 29 is in its'outermost'or forward position,

lever is preventedfrom being moved when the locking ball 73 ls'recelve d'iln eitherof the recesses 10, 7.1.lt will be apparent thstatter the trl'ggerV'ZB. has been deprossed 'just a 'short cess 771 is disposed over the locklngball. Thereversing distance-the locking'ball l3 will be .carnmed into one of they jcther recesses 70. 71 to prevent mevems toreversing bar 19. Refereneeshould be had to the aforesaid Frenzel U.S.'l 'at.

7 No. 3.260.827 for otherto'rrns of interlocking mechanlsmf During the course of assembly. the locl'ring ball' 73' is dropped into the recess 74 through a palrof ope'nings'76.-7 7.

The opening" may lie-suitably plugged during final assembly otthe triggerractueted switch unit.

'As-noted'lnFiG. i, the unitary mounting boards! also su ports'a plurality ofprlnted contact strlps'and formations in 7 eluding strlpaf'ili flfto establish the appropriate current i r paths asindicatcd schemetically in FIG. 6. The contact strips 81. 82 and llsrc' caciisconnected'to a spring clip terminal;

which are suitably secured tegethcrrara contained within an outer housing or casing (not' shouin). Any-suitable construc f tlen'well known to thosesltillad'ln the art maybe provided for -thls purpose, J I

- f it wllllb'eseen that thafprcscnt invention provides a unitary mounting besrd'whichsupports the contacts to provide the necessary switehin'gi bcth for "lorw'ardfi "reverse." "enei'f" a. said unit including a housing; 7 5

.Weclaim:

i l. in atrigger-operated switch unit for installation inia portable electric tool orthc like, the improvement comprising:

b'. a trigger movably. mounted bysaid housing; c. a reversinglever movably. mounted by said housing; d.-first andrseeond contact means in' said hou'sing and carried respectively by said trigger and said-reversing lever V for movement therewith; Y I ep mea'ns in said housing defining a unitary contact and cir- V cuitmountingboardi a I i f. third and fourth contactmeans fixed to said mounting board and arranged for respective engagement by said g i v firstand secondcontactmcans; Y

g. firstcircuitelcments on said board cooperatingwith said first and third contact means to define ajcircuit foricnerj gizing the associated .toolmotor upon actuation of said I trigger; and

a h. second circuit elementson said board coo perating with I said second and fourth contact means to defineacircuit for establishing thedirection of rotation of the associated 1 tool motor upon actuation of said reversing lever.

T2; The improvement according'torclaim 1 further defined f 'a. said-second co'ntact means being defined by a pair of contact elementsicarriedby the reversing lever; I

b. said fourth contact means being defined byfive contact members mounted on said'board in spaced relation from c eachothenand ic. said pair of contactelements establishing a current path through said said first and second contact membcrs and another current path through said third and fourth'con tact members-when said reversing lever is in one positions I 'thereofl'said pair of contact elements establishinga cur" rent path through said second and third contact members and another current path through said fourth and fifth" contact members when said reversing leveris in the other.

of its two positions. V v 3. The improvement accordingto claim 1 further defined y g 7 v ,7

and a b. said third contact means lncludinga plurality of contact 1 i 7 strips on said board arranged for beingslidably engaged by respective contact fingers. 4. The improvement according to claim said fingers and one of saidcontect strips cooperate to define a variable resistor forming part of a variable speed control circult constituting said that mentioned circuit.

' 5. The improvement according to claim 4 further-defined V by, a printed circuit board secured to said mounting board} said circuit board carrying said one contact strip. 7 l i i 6, The improvementaccordingto-claimj wherein said first circuit elements are mountedon saidcircuit board.

70 fandffbypass." Further. this hoard -supports a-circuit board which in turn mounts all of the electronlccompcnents to defi'ncaspced control systamManifa'stly. the mountingboard providcslor casysnd lowcos't manufacture among other ed= vantagesz V v 7. The improvement accordlngto claim further defined asaid second contact means being defined by a pair dfcon- 6o tact elements carrled by the reversing lever;

, each other; I I U I c. said pairs of contact elements establishing a current path members mounted on said board in spacedreiation from through said tlrst and second contact members and anothsr'e'urrent path through ssidf'third and fourth con positions thereof, said pair of contact elements establish and fifth contact memberswhe'nzsaid reversing lever is in the other of its we positions; i d. said first contact means including a plurality of contact fingers carried by said trigger for movement therewith;

and

. a. said first contactmesnsincluding a plurality of contact v fingers carried by said trigger for"mevernenttherewith;

3 whereinone of i b. said fourth contact means being defined by five contact tact members when said reversing lever is inone of two 7 lng e currentpath through said second and third contact members and another current path through said fourth c. said third contact means including a plurality of contact strips on said'board arranged for being slidably engaged by respective contact fingers.

8. The improvement according to claim 7 wherein one of said contact fingers and one of said contact strips cooperate to define a variable resistor forming part of a variable speed control circuit constituting said first mentioned circuit.

9. The improvement according to claim 8 further defined by, a printed circuit board secured to said mounting board, said circuit board carrying said one contact strip.

10. The improvement according to claim 7 wherein said circuit board mounts said first circuit elements.

11. In a trigger-operated switch unit for installation in a portable electric tool or the like, the improvement comprising:

a. said unit including a housing;

b. a trigger movably mounted by said housing;

c. a reversing lever movably mounted by said housing;

d. first and second contact means in said housing which are moved in response to movements of said trigger and said reversing lever, respectively;

. said first contact means including a wiper finger; means in said housing defining a unitary contact and circuit mounting board;

. third and fourth contact means fixed to said mounting board and arranged for respective engagement by said first and second contact means;

. a printed circuit board secured by said mounting board other circuit elements on said board in direct physical contact therewith and cooperating with said second and fourth contact means to define a circuit for establishing the direction of rotation of the associated tool motor upon actuation of said reversing lever.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Carl J. Frenzel and Alex F. Gawron errors appear in the above It is certified that d Letters Patent are hereby identified patent and that sai corrected as shown below:

Column 3, line 25, insert a period after "position"; delete "to" and insert -To-.

Column 4, line 33, after "one" insert -of two-.

Signed and sealed this ll th day of March 1972.

(SEAL) Attest:

ROBERT GOTTSCHALK EWARD M.F'LETCI ER,JR.

Commissioner of Patents Attestins Officer

Claims

1. In a trigger-operated switch unit for installation in a portable electric tool or the like, the improvement comprising: a. said unit including a housing; b. a trigger movably mounted by said housing; c. a reversing lever movably mounted by said housing; d. first and second contact means in said housing and carried respectively by said trigger and said reversing lever for movement therewith; e. means in said housing defining a unitary contact and circuit mounting board; f. third and fourth contact means fixed to said mounting board and arranged for respective engagement by said first and second contact means; g. first circuit elements on said board cooperating with said first and third contact means to define a circuit for energizing the associated tool motor upon actuation of said trigger; and h. second circuit elements on said board cooperating with said second and fourth contact means to define a circuit for establishing the direction of rotation of the associated tool motor upon actuation of said reversing lever.

2. The improvement according to claim 1 further defined by: a. said second contact means being defined by a pair of contact elements carried by the reversing lever; b. said fourth contact means being defined by five contact members mounted on said board in spaced relation from each other; and c. said pair of contact elements establishing a current path through said said first and second contact members and another current path through said third and fourth contact members when said reversing lever is in one positions thereof, said pair of contact elements establishing a current path through said second and third contact members and another current path through said fourth and fifth contact members when said reversing lever is in the other of its two positions.

3. The improvement according to claim 1 further defined by: a. said first contact means including a plurality of contact fingers carried by said trigger for movement therewith; and b. said third contact means including a plurality of contact strips on said board arranged for being slidably engaged by respective contact fingers.

4. The improvement according to claim 3 wherein one of said fingers and one of said contact strips cooperate to define a variable resistor forming part of a variaBle speed control circuit constituting said first mentioned circuit.

5. The improvement according to claim 4 further defined by, a printed circuit board secured to said mounting board, said circuit board carrying said one contact strip.

6. The improvement according to claim 5 wherein said first circuit elements are mounted on said circuit board.

7. The improvement according to claim 1 further defined by: a. said second contact means being defined by a pair of contact elements carried by the reversing lever; b. said fourth contact means being defined by five contact members mounted on said board in spaced relation from each other; c. said pairs of contact elements establishing a current path through said first and second contact members and another current path through said third and fourth contact members when said reversing lever is in one of two positions thereof, said pair of contact elements establishing a current path through said second and third contact members and another current path through said fourth and fifth contact members when said reversing lever is in the other of its two positions; d. said first contact means including a plurality of contact fingers carried by said trigger for movement therewith; and e. said third contact means including a plurality of contact strips on said board arranged for being slidably engaged by respective contact fingers.

11. In a trigger-operated switch unit for installation in a portable electric tool or the like, the improvement comprising: a. said unit including a housing; b. a trigger movably mounted by said housing; c. a reversing lever movably mounted by said housing; d. first and second contact means in said housing which are moved in response to movements of said trigger and said reversing lever, respectively; e. said first contact means including a wiper finger; f. means in said housing defining a unitary contact and circuit mounting board; g. third and fourth contact means fixed to said mounting board and arranged for respective engagement by said first and second contact means; h. a printed circuit board secured by said mounting board with the former in coextensive physical contact with a portion of the latter, said printed circuit board carrying a plurality of elements defining a speed control circuit, one of such elements being a resistance strip slidably engaged by said wiper finger upon movement of said trigger; and i. other circuit elements on said board in direct physical contact therewith and cooperating with said second and fourth contact means to define a circuit for establishing the direction of rotation of the associated tool motor upon actuation of said reversing lever.