US2773144A

US2773144A - Snap action switch

Info

Publication number: US2773144A
Application number: US352096A
Authority: US
Inventors: Ralph B Immel; Wibell Martin
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1953-04-30
Filing date: 1953-04-30
Publication date: 1956-12-04
Anticipated expiration: 1973-12-04

Description

United States Patent SNAP ACTION SWITCH Application April 30, 1953, Serial No. 352,096

9 Claims. (Cl. 200-67) Our invention relates, generally, to electric switches and, more particularly, to switches which operate with a snap action and are of the general type described in the copending application of R. B. Immel, Serial No. 222,203, filed April 21, 1951 now Patent No. 2,748,214, issued May 29, 1956 and assigned to the Westinghouse Electric Corporation.

An object of our invention is to improve the mechanical structure of a plunger-operated snap-action switch.

Another object of our invention is to simplify the assembly of a two-position, plunger-operated snap-action switch.

A further object of our invention is to provide improved operating springs for a snap-action switch.

' Still another object of our invention is to provide for securing the operating springs in the operating button of a plunger-operated snap-action switch.

A still further object of our invention is to provide a simplified means for securing the contact base assembly to the cover of a snap-action switch.

Other objects of our invention will be explained fully hereinafter or will be apparent to those skilled in the art. In accordance with one embodiment of our invention, two separate operating springs are so disposed in the molded operating button of a switch that they are the equivalent of a U-shaped spring, but since no bending is required more accurate springs can be manufactured with relatively simple tools. The moving contact system, which includes the operating button, operating springs, moving contact member and toggle links can be easily assembled with the stationary contact base by initially positioning the major axis of the moving contact system perpendicular to the longer axis of the base and then rotating the assembly through 90. into its final position. The contact base is secured to the cover by special clips which engage contact members on the base.

For a better understanding of the nature and objects of the invention, reference may be had to the following detailed description, taken in conjunction with the accom-. panying drawing, in which:

Figure 1 is an enlarged view, partly in section and partly in side elevation, of a switch embodying the principal features of the invention;

Fig. 2 is a view, in side elevation,.of the moving contact assembly of the switch;

Fig. 3 is a view, in section, of the push button and operating spring assembly;

Fig. 4 is a bottom plan view of a portion of the contact base and switch cover;

Fig. 5 is a top plan view showing the manner of assembling the moving contact assembly with the contact base;

2,773,144 Patented Dec. 4, 1956 ice Fig. 9 is a plan view of the bearing for the guide pin of the switch.

Referring to the drawing, and particularly to Fig. 1, the switch structure shown therein comprises a generally rectangular contact base 10, which may be molded from a suitable insulating material, and a cover 11 which may be attached to the base in a manner more fully described hereinafter. The cover 11 may be molded from a suitable insulating material. As shown, the cover 11 has a generally rectangular opening 12 therein for receiving a reciprocating operating member 13 for actuating the switch mechanism, as will be more fully described hereinafter. The cover 11 is provided with mounting holes 14 for mounting the switch unit in one plane and mounting holes 15 for mounting the switch in another plane at right angles to the first plane.

As shown in Fig. 1, spaced contact members 16 are disposed in the base 10 in line with the longer dimension of the base. Each contact member 16 is generally of a U-shape having one leg attached to the base by means of a rivet 17. The contact members 16 may be composed of any suitable electrical conducting material. Each contact member 16 is provided with a contact 18 which is preferably composed of silver or a silver alloy. Terminal screws 19 are provided for making electrical connections to the contact members 16. A contact member 21 is associated with each contact member 16 and each contact member 21 has a contact 22 disposed above and spaced from its associated contact 18. The contact members 21 are attached to the base 10 by rivets 17 and terminal screws 19 are provided for making electrical connections to the contact members 21.

A bridging contact member 23 is movably disposed between the upper pair of contacts 22 and the lower pair of contacts 18. As shown most clearly in Figs. 5 and 6, the bridging contact member 23 is generally rectangular in shape and has a generally rectangular opening 24 therein. The member 23 may be formed from a relatively thin sheet of conducting material such as beryllium copper.

The rigidity of the member 23 may be increased by providing downwardly-turned flanges 25 at its outer edges and similar flanges 26 at the sides of the rectangular opening 24. In this manner the contact member 23 may be relatively light in weight, but at the same time relatively rigid. Thus the contact member 23 has a low inertia and can be operated with a fast snap action.

The bridging contact member 23 is provided with upper and lower contacts 27 at each end which are disposed to engage either the contacts 18 when the bridging contact member is in its lowermost position, or the contacts 22 when the bridging contact member is in its uppermost 'Fig. 6 is a top plan view of the assembled moving contact assembly and contact base; Fig. 7 is a view, in plan, of a clip for securing the contact base to the cover; 1

Fig. 8 is a view, in side elevation, of one of the op erating springs; and

position. The contacts 27 are preferably composed of the same material as the

contacts

18 and 22.

As shown, the switch operating member 13 is in the form of a push button and it may be molded from a suitable insulating material. The top of the push button is rectangular in section and the reciprocating movement of the push button is guided by the sides of the rectangular opening 12 in the cover 11. A flange 28 is provided on the sides of the push button to engage shoulders 29 on the cover 11 to limit the upward movement of the push button 13. i

As shown in Fig. 1, two oppositely disposed operating springs 31 are inserted into the push button 13 and a guide pin 32 is inserted into the push button between the operating springs 31. As shown. most clearly in Fig. 8, each spring 31 is substantially flat and has a slot 33 at itsupper end, thereby providing two spring arms. Each spring arm has a projection 34 thereon.- As shown in Fig. 3, the spring 31 may be inserted in a slot 35 in the molded push button 13 and the spring is retained 3 in the push button by the projections 34 engaging the molded material of the push button.

As shown in Fig. l, the upper end of the guide pin 32 has a slot 36 therein, thereby providing two arms on the end of the guide pin. Each arm has a projection 37 thereon which engages one of the springs 31, thereb holding the springs against the sides or the pu h button 13 and also retaining the guide pin in the push button. In this manner, the parts of the operating member 13 are securely held together.

shown most clearly in Fig. 1-, the lower end Of the guide pin is disposed in a bearing 38 which is rotatably mounted at the top or a recess 39 in the base 10. The bearing 33 rests on -a sho'ul-d'e'r dl in the recess neon spring enemas the guide pin 32 and extends hett eeh' the t? at the hearing as she a s aman as or: guide In this ihahner, th spring 4 2 is 'eehtpiess'ed when the push button 13 is pressedd'owm wardl'y and it r tu'rns the push button to its upp'er'mo st position when the button is released.

' as she's/"h ihj 'st 'cle irly in Figs. 1 am "2, the bridging er 3 is cd'nn'ec'ted t'o the foperating spririg s 31 bya'pair 'of'ri gfid tog'gleleve'rs "44. Each toggle 'lev'er 4 1 is disposed between the lower end of one the o" ting sprin s '31 and one end of the rectangular opening '24 in the bridging contact member 23. Each ppeiating s'pririg 13 has a groove '45 near its lower end forrebeiving'dne eh'd o fjthe tog le lev r 44. An openg a projectio 44' n the levcr44 to prevent be end o'f the lever from jumping out of'the groove 45. The other "ehd of the toggle lever 44 has a downwardly bent flange 46 thereon forfengaging the edge of the contact member 23 at the end of the opening 24. The flange 46 may'have a groove and opening therein, "similar to the groove 45 and opening 45 in the spring 31, for receiving the edge of the contact member 23 and a projection. 23' on the contact "member,

As shown in Fig. 2, the entire moving contact system of the switch mechanism which comprises the push button 13, the operating springs 31, the guide pin 32, the bridging contact member 23 and the toggle levers 14 can be assembled as a unit prior to its installation in the switch structure; As shown, the upward movemerit of the bridging contact member is limited by its engaging the lower edge 47 of the push button 13. I

As shown in Fig. 5, the moving contact system can be readily assembled with the stationary contact base 1t) byinitia'lly positioning the major axis ofthe moving systematfright angles to the longer axis of the Contact base. The'coil spring 42 is placed on the guide pin-32 and the lowe'r iend of the guide pin is inserted into the bearing 38. With thebridging contact member 23 held at the coifr'ect level, the entire moving system can be re" fed 94) into theposition shown in Fig 6 with the contacts '27 disposed between the contacts '18 and 22. rotated90 into theposition shown in Fig. 6 with the guide-pin 32. i i iter the assembly of the operating mechanism in the foregoing'manner, the cover :11 isplaced'on the base "t ephsh button 13 extending through-the opening'12. Ksbhown mostclearly in Figs. 1 and 4, the cover means i e lg ps shown'in Figs. 4 and 7, each clip has aproj'ection '49 thereon which is disposed in a slot-51 in one of't'he contact members 16 -or 21. A self-tapping screw 52 maybe threaded into the cover 1'1 to hold the clip 48 'in 'pos'ition, thereby securely holding the base and thecbvertogethe'r. v I

-As shown inFig. 1, the push button 13 is normally biased to its uppermost position by the spring 42 and the bridging contact member 23 is normally biased to its lowermost position by the toggle levers 44 and-the operating springs 31 which ar stressedat all times when is 'b i o u t pr n 31 f e assembled in the switch mechanism, Thus thecontagts 27 on the bridging member 23 are held against the lower cont-acts 18 with sufficient contact pressure to enable the contact members to conduct relatively heavy currents.

When the push button 13 is depressed, the operating springs 31 are stressed still further until the ends of the toggle levers 44 which engage the springs 31 pass overcenter, thereby causing the bridging contact member 23 to be actuated upwardly with a fast snap action. The upward movement of the bridging contact member 23 is limited by the upper contacts 27 engaging the con tac't's 22. The operating springs 31 are still under stress, thereby maintaining a good contact pressure between the upper contact members.

when the push button 13' is released, the coil spring 42 returns the push button to its uppermost position, shown in Fig. 1, thereby actuating the bridging contact member 23 downwardly by stressing the operating springs 31 until the toggle levers 44 pass overcent er. Thus a snap action is obtained during operation of the bridging contact member 23 in either direction.

' From the foregoing description it is apparent that we have provided a switch structure which has numerous advantages, some of which are as follows: The operat ing's'prin'gs may be easily and accurately manufactured with relatively simple tools, since no bending of the springs is required. The operating springs and the guide pm m be "readily assembled in the push button and they are self-retaining in the push button. The moving parts of the switch mechanism may be readily assembled with the stationary contact structure, thereby facilitating the assembly of the entire switch structure. The forc going features make it possible to manufacture and assemble the switch economically and to provide a mechanically superior switch structure. c

Since numerous changes may be made in the above described construction, and difierent embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all the matter contained in the foregoing description or shown in the -'accbrnpanying drawings shall be interpreted as illustrative-arid not in a'limiti'ng sense.

We claim as our invention:

1. Inia'switc'hgin combination, a generally rectangular cdn'tact baseofinsulating material, a pair of spaced contact'metribers'disposed in line with one dimension of the base and securedto "the base, an additional contact membe r disposed above and spaced from each one of the firstnam'ed conta'cfmember's,said'additional contact'member's being-secured to the base, a bridging contact member movable into and out of bridging-engagement withsaid s'ecu'teti contactmembers, a reciprocating-operating merr ber -having' two oppositely-disposed slots therein, a'sepa ly mounted sub"stantiall-yiiat operatingsp'ring disposed h are: in the operatingmember, substantiallyrigid ie ev'eis'counecting said'springsandsaid'hridgingtontact nienilier to iictuate the latter, said bridging contact member having a generally rectangular "ope'ning therein fofre c'eiving the' t'oggle levers, a 'guidepin dispos'ed in'the opfatin'g member b'etween sa'id springs, 'means extendmg from the guide pin for engagingthe'springs to retain them 'in the 'ope rating' rriembe'r, a'coverfor the switch, a recess in said base, and a bearing in said reec's's 'fo'r the lower end of s'aid'giiide pin, said bridging "contact-member being rotatable about said guide pin asan-axis in'a plane parallel to the contact hase'w'hen the lower endof the guide pin is in said bearing and prior to the installation' ofthe cover.

*2. *In-a switch, in combinatioma generally rectangular contact base of insulating material, -a;pair of spaced con: tact meinbers disposed inline with onedimensi'on o f-the base and secured to the base,jan additional contactmem: ber disposed above and spacedfrom each one of the firstname d contact members, said additional contact members being secured t o the base, a bridg ing contactmembermovable into and out of bridging engagemeutwith s'aidse need contact members, a reciprocating operating member having two oppositely disposed slots therein, a separately mounted operating spring disposed in each slotin the operating member substantially, rigid toggle levers connecting said springs and said bridging contact member to actuate the latter, said bridging contact member having a generally rectangular opening therein for receiving the toggle levers, a guide pin having one end disposed inthe operating member, a cover for the switch, a recess in said base for the other end of the guide pin, and means on the guide pin for engaging said springs to retain them in the operating member, said bridging contact member being rotatable with the operating member about the guide pin as an axis in a plane parallel to the contact base when one end of the guide pin is in said recess and prior to the installation of the cover.

3. In a switch, in combination, a generally rectangular contact base of insulating material, a pair of spaced con tact members disposed in line with one dimension of the base and secured to the base, anadditional contact member disposed above and spaced from each one of the firstnamed contact members,rsaid additional contact members being secured to the base, a bridging contact member movable into and out of bridging engagement with said secured contact members, a reciprocating operating member having two oppositely disposed slots therein, a separately mounted substantially fiat operating spring disposed in each slot in the operating member, substantially rigid toggle levers connecting said springs and said bridging contact member to actuate the latter, each spring having a groove therein for receiving one end of a toggle lever, said bridging contact member having a generally rectangular opening therein for receiving the toggle levers, a guide pin having one end disposed in the operating member, a cover for the switch, a recess in said base for the other end of the guide pin, and means on the guide pin for engaging said springs to retain them in the operating member, said bridging contact member and said toggle levers being rotatable with the operating member about the guide pin as an axis in a plane parallel to the contact base when one end of the guide pin is in said recess and prior to the installation of the cover.

4. In a switch, in combination, a generally rectangular contact base of insulating material, a pair of spaced contact members disposed in line with one dimension of the base and secured to the base, an additional contact member disposed above and spaced from each one of the firstnamed contact members, said additional contact members being secured to the base, a bridging contact member movable into and out of bridging engagement with said secured contact members, a reciprocating operating member having oppositely disposed slots therein, separately mounted substantially fiat operating springs oppositely disposed in said slots in the operating member, substantially rigid toggle levers connecting said springs and said bridging contact member to actuate the latter, said bridging contact member having a generally rectangular opening therein for receiving the toggle levers, a guide pin having one end disposed in the operating member, a cover for the switch, a recess in said base for the other end of the guide pin, and means on the guide pin for engaging said springs zto retain them in the operating member, said bridging con- :tact member and toggle levers and operating springs and operating member being rotatable about the guide pin as :an axis when assembled together on the contact base with one end of the guide pin in said recess and prior to the installation of the cover.

5. In a switch, in combination, a generally rectangu- .lar contact base of insulating material, a pair of spaced contact members disposed in line with one dimension of the base an additional contact member disposed above and spaced from each one of the first-named contact memzbers, a bridging contact member movable into and out of bridging engagement with said spaced contact members, a

reciprocating operating member having oppositely disposed 'slots therein,separat'elymounted operating springs oppositely disposed in the slots in the operating member with less than one-half the length of each spring extending below the bottom of the operating member, rigid toggle levers connecting said springs and said bridging contact member to actuate the latter, said bridging contact member having a generally rectangular opening therein for receiving the'toggle levers, each toggle lever having a fiange on one end for engaging one end of the opening in the bridging contact member, said bridging contact member and toggle levers being retained with the operating member by the operating springs as a preassembled unit when the other ends of the toggle levers have pased through the opening in the bridging contact member causing the bridging contact member to engage the lower edge of the operating member prior to the installation of the preassembled unit in the switch.

6. In a switch, in combination, a'generally rectangular contact base of insulating material, a pair of spaced contact members disposed in line with'one dimension of the base and secured to the base, an additional pair of contact members having one contact member disposed above and spaced from each one of the first-named contact members, said additional contact members being secured to the base, anelongated bridging contact member movable into and out of bridging. engagement with said secured contact members, a reciprocating operating member, separately mounted operating springs oppositely disposed in the operating member, rigid toggle levers conecting said springs and said bridging contact member to actuate the latter, a guide pin having one end disposed in the operating member, a recess in said base for the other end of the guide pin, said guide pin being perpendicular to the contact base, and a cover for the switch, said cover having an opening therein for the operating member, said bridging contact member being rotatable between said pairs of contact members in a plane parallel to the contact base about the guide pin as an axis prior to the installation of the cover.

7. In a switch, in combination, a generally rectangular contact base of insulating material, a pair of spaced contact members disposed in line with one dimension of the base and secured to the base, an additional pair of contact members having one contact member disposed above and spaced from each one of the first-named contact members, said additional contact members being secured to the base, an elongated bridging contact member movable into and out of bridging engagement with said secured contact members, a reciprocating operating member, separately mounted substantially flat operating springs oppositely disposed in the operating member, rigid toggle levers connecting said springs and said bridging contact member to actuate the latter, said bridging contact member having a generally rectangular opening therein for receiving the toggle levers, a guide pin having one end disposed in the operating member, a recess in said base for the other end of the guide pin, said guide pin being perpendicular to the contact base, and a cover for the switch, said cover having an opening therein for the operating member, said bridging contact member being rotatable between said pairs of contact members in a plane parallel to the contact base about the guide pin as an axis prior to the installation of the cover, said cover and said operating member cooperating to prevent rotation of the operating member and the bridging-contact member when the cover is in position on the switch.

8. In a switch, in combination, a generally rectangular contact base of insulating material, a'pair of spaced contact members disposed in line with one dimension of the base and secured to the base, an additional pair of contact members having one contact member disposed above and spaced from each one of the first-named contact members, said additional contact members being secured to the en ou Of b id i en age ent t v. i v k membe a eiereea ing pe e memb r, sepa ately w eni ii e t e flat operating sp epee it iy i Pe e in th Operating me ri id te e eve s em necting said springs and said bridging contact member to ctu t e S b d n onta t me be ha ing a ene al r t ngula open g r in fe receiving the e e e l e a i e i ha on en di P d in the operating member, a recess in said base for the other end of the guide pingsaid guide pin being perpendicular to the contact base, and a cover for the switch said cover, having en pe in h re for t e p teting membe said tone ating member and said bridging contact member being roat -ble ou the e depi a e e i rie t in ta leti n o t e e en s id b d n cen e m mb r ati in. a ela e e e t he as e we i pai of tact members, and clip means attached to the cover and engaging the contact base to secure the "contact base to the tcover.

9- :In a switeh, in mb n ti n, ee e ly re an ular c nt c base of ns l ng teria Ia p i of space c ntact members disposed in line with one dimension KQf :the base and secured to the base, an additional Pair of icentact members having one contact member disposed above and spaced from each one of the firstenamed contact members, said additional contact members being secured .to the base, Jan elongated bridgingcontact member movable into and out of bridging engagement with :said secured base, en elenee b d n eont t, member mei ebie nt-e eeateet members, e reeiprmeting opera-ting member, see: a 1y n opetatill sprin s eppesitely s1. eesesi the {m te ing membe r gid teggle ie ere. eenn eting said prin s nd. e d de-vine enteet emb r; a ate the et er 4 side P n h vi g ne end di pesed 5: 2 t e ep-etet e embe a e ess in aid base fe he ether end 9f the snide pin, said g id p n ein P mendieu ar t9 he e t t bee z end B cover t th sw h, s i co er be e an enemies; e ein for t e pe a ing ember, s id epexae t i member n S i b d en e t member eing It. et bl i ide pin as an axis P r 9 t e in tall? lion of the co er, s d br dg eonte' t member retatins in e P a e. P a el to he as en s i ai of een tact membe S id eover and, s id ep rating membe @9- Qneret n te ee tente e -i n 0t th -ep titie em er d the bridging contact member when the cover is in pp on en the swit h, n c ip means attached te the ent a n a in c t t m m ers 0 1 t e n ee base t .seeure the base to the cover.

Re e ee Ci e he fi 9 he et n UNITED STATES PATENTS 2,332,911 Hausler Oct. 2 6, 1943 2,384,412 Woods Sept. 4, 1-945 2;;519297 Stump et a1. Aug. 15, 1950 2,508,628 Dietrich Aug. 26', 1952 FOR IGN PATENTS 546,135 7 Great Britain June 29, 13942