US2515078A - Switch device - Google Patents

Description

July 11i, 1950 H. A. cowARDlN 2,515,078

SWITCH DEVICE Filed July 3, 1946 @M M9 LM/ZUM Patented July l1, 1950 i'ES OFFICE SWITCH DEVICE Gowardin-executrix ofgsa-id- Harry A.'Cowar Application-July- 3, 1946;' Serial No. 681,173

i-65Claims. (Cl.200-27) L1 2 "5iThSfinVentOnflEl'teSi O'aSWCha-.mehanisms @usedinfconjuncton with my dei/ica Arms lly :fand-.more'particularly-to sWitchfmechanismsif-Or flsandf I9 are supported cn plate In and secured plr-cW-iding :periodic .-contact of; predeterminable :thereto by suitable boltsiy I'I, Ila and lggrespec- -,finterva1s, .rtivelyytheconstruction and arrangement being To the best-Toffmy-knOWiedgQ'lIiOr-attemptStOi:5 suchthatfthe three arms which are formed of "construct:switches-ofthe .class :described .have bent-'metal strips substantially yasshown,` vare V@faillenl shortf-o complete success 4for a\.fnumber.of .pivotally related tex-plate IU and` to each other. -'treasonsg flnfrthefcase of.'y mechanisms .whichzuse :Armi Il, is biased towards `arm I8 by means ofa v@wipe contacts'thefarcing-andburning of Athe-con- '.,leafxspring' 22 wrapped about a portion of the tact'frnembersasoonaffect-the'duration of Contact;` lesurface -of yarm VI vand securedY thereto as'by a ;-;Fur1;her, the' stationary-contact members-msnen :rivet 24. The free end of spring :22 abuts afxed 'xgvtypmoffwitchi have aitendencyuto'bounce'- which apostn-Efsecured `iso-platey i0. Accordingly, it -will :spiroducesaseriesof short-.contactsrather tharra ``De -un'derstood that arm Ilis resiliently biased 1-fsingleecontact offdeimiteduration. f "In-switches :towards arm I3. #Arm I9 is provided with a spring vrofithe-cam operated type, the contactsmembers 16? 28;;similarlysecured. thereto as by a rivetfs and --arel-particularlysusceptible to? bouncingandf'in .thefree end-offspring 2S abuts a xed post 32 ffsuchfoases where one offthefcontaot members: is -asecuredfto plate it. Accordingly; it willi-be un- =sprir1gaccelerated failure tol-acceleratefrapidly fderstood-thatffarm I9 isv resiliently biased away 'enoughiwill cause-.a variation inctime -or' contact 'ff'rom arm I8. Arm I'I carries a.V cOntact point 34 f'interruptions'of the contact. `zonadapteclto normally engage a contact point` 36 ..AC00rding1y :i1-,ais .an Object fof-myfinvention to AOn-arm liduefto the' biasfof spring 22. Arm I'I aprovide a switch mechanismtofv the c1assdescribed falso Carries an abutment means comprising a .Lwhich? eliminates the-'difculties'hereinaboverset @member 31# of lany Suitable insulating material. 0M-,1L f-Armffi' carriesanabutrnent means Ill normally --Itfisa:furthep=-0bjeCu;0f--.myf invenzioni@ .pro- .25.. spaced fromfmember 1131. Abutment means 4D -Y'ivide Ja mechanismwhaving aminimum .of -moving 'may fllnpliSea metalli@ rivet having the dual :.membersfandwhich readilylends'itselfffopmanullnCtlOnOf selllng arm i8 in the desired shape :'vfacture'zby massproduction methods. nd-21450 affording 2t Contact pOnt -42 on the -Inrfachieving the abovewobjectsl provideafa Aunderside .ofarm I8. Arm l'carres a contact :switch structure wherein' the=duration of contact 3Otpolnt 44 nOrmaHy spaced from contact point 42 rbisadjustably"determimed-by varying .the-lengthof #byiVlrtue-of the biasing action of spring 28.

travel between a pair of periodically abutting '1-A"Cm"m\mbe` 50 S' SGC-Wed @CCeDtTiCaill/to'a :fmembers Furthen Arnv-contactmembers.'A are so #gear 53 (Figli-T65), which is mounted concentrisdevised esitate -heiduogetheratfthe :point-.cf emily :with platefi!! on a rotary shaft t5, cam 5o lcontacirbya forcezequal'tofthesumfof the-pres-35vbemgalanged:t0 YOtSteWth'gG/MSS relative `:lsu-reioeapluralityofsprings assooiatedswithzsaid -tQrP1at Ill soasI to-engaee arm i9 as shown in ,fqmembers :aridzadapted .toV biasirespective-memiFlg-unesrandz. yWith Yreference to Figure 5,-fa bers to a position of rest. This holding force .is #Portion 0f- Be'dlvng'gearr 53 is shown whichamay .augmente'diby inertia forces-developedinaocelibex-{assumed tqfbpartf the mechanism A,with

erating the Contact members. My structure .isf4 -ffWhlChlmy' deVlCGlS lSSOCittei and it wil1-beim '.-.such.fasto provide-smooth yoperationwith, howdefs/*5091i 1hat"ltOt'dtlOIi 0f at e., uniform .-j'ever, abrupt interruption of contact. flspeeii mpartsfby Virtue Offgear 53 and cam,

:My Yinifentionpwillnow, be describedrinffletailin 'ha umfofm Periodic OSOllatOn to arm I9, theexfpconjunction-withfthe.accompanyingdrawingsin *tent Off Yet-um travel Ufa-Tm 9 being determined whichz v f by a xedpostll secured. to plate I0.

4 V Figures [email protected] D `'I'heleetrica-lswitch ofthe present invention tions offtheK elementsnof my, mechanism during@ L-s intended to control. an Aelectrical circuit which complete cycle offoperation,1-Figure1being: a secflciudes lbolts. Wand I9. It will beappreciated ,-gionlhrough 0f.:Figure;f-,andFigure'S'being .thatrotaton of-camivfcausesinitial engagement ,eased-,ion thmughfsnflj OfFguL 50 between poi-ntsJIZ and-t4, whereupon current can i With-reference-toxthe ,idrawingsmy.invention fflow'betweengbolts iI'I and I8 by virtue .of en- `comprises-a .supporting--platef I0 vof-'any suitable .gaged contactfpoin-ts 34. and '36. -Thiscondition Y.insulatingmaterial and1which islseouredeby bolts sisiy shown inlzig. 2. Continued'rotation .of/cam i'I2f.:to,:a stationary post '.'I5,r ;.or.- otherstationary sillasshownzin' Figure 3,1causes engagementof @..me-mber.associatedovitlrtheparticular-equipment., 5 abutment.V meansv 40 with-31, which serves, .tor in- 2,515,078 :tif -f i;

terrupt the contact between points 34 and 3B by virtue of the difference in angular velocities of the overlapped portions of arms I1 and I8 whence current between bolts I1 and I9 ceases. Further rotation of cam 50, as shown in Figure 4,

further increases the gap between contact points` `feature of this invention resides in the arrange-A ment of the operation of the contacts 34 and 36 to compensate for the wear of these contacts. It will be seen that since the contacts 34 and 38 will decrease in thickness due to wear and burning, the abutment members 31 and 40 will likewise decrease in thickness due to wear. By suitable choice"of material forl these contact points and they abutment members 31 and 40, it is contemplated that the effect of the decrease in thickness of the contact points 34 and 36 will be com- `pensated for by the decrease in thickness of the the posts I3 Vand I9 in the event it is desired to operate the device as a single pole double throw switch.

the device may be used as a circuit breaker for a I circuit between the bolts I1 and I9. In the latter event the closing of the circuit is eiected by the contacts 42 and 44 while the opening of the circuit is effected by the disengagement of contacts 34 and 38 as will be hereinafter described. When the cam 5B rotates in the direction of the arrow, the lower end of the arm I8 will be moved to the left as Viewed in Figure 1, so that contacts 42 and 44 are engaged to close the circuit. The circuit from bolt I 1' to bolt I8 will remain closed during the time the cam 58 continues to move the lower end of the arm I 8 to the left which thereby moves the arm I8 counter-clockwise until the abutment 48 engages the insulating abutment 31 on the arm I1. As will be seen from the drawings, by virtue of the fact that the arms I1 and I8 are irespectively pivoted about spaced points and by virtuev of' the fact that there are portions of these arms which overlap, there will be a difference in the angular velocities of the contacts 34 and 38 so that they will be disengaged as soon as the abutment 48 engages the abutment 31, thus breaking the circuit between posts I1 land I9'.

i As the cam 58 continues to rotate in the direction of the arrow, it will engage the underside of the arm I8 and hold the latter in a xed position against the action of the spring 22 which resiliently biases the arm I1 against the arm I8, and from an inspection of the drawings it-will be noted that the cam 58 will be disengaged from the lower side of the arm I9 before it is disengaged from the lower side of the arm I8. This rThus it will be seen that the circuit between posts I1 and I9' is closed by virtue of engagement of contacts 42 and 44 and the same circuit is opened by virtue of disengagement of the contacts 34 and t5V and because of the subsequent sequential operation of snap-back action of arms I8 and I8 the contacts 42 and 44 are opened before contacts 34 and 36 are subsequently closed. This insures that a circuit is broken only at the points 34 and 36. As will be clearly understood, the greater amount of burning, wearing and deterioration of electrical contacts occurs upon the opening `of an electrical circuit rather than upon the'closing ofthe circuit. To this end, aisalient..

abutment members 31 and 40. Referring specifically to .Figure l, it will be noted that should the contacty points 34 and 3S decrease in thickness, the abutment members 31 and 48 will decrease lin substantial proportion and it will take substantially the same amount of movement of arm I8'to disengage the contacts 34 and 36. In

other words, the wear between the contact points will be substantially neutralized by the wear between. the abutment members so that the net effect will be that the duration ofintermittent electrical contact will remain substantially constant over long periods of operation.

- It will be readily apparent that the present mechanism is adapted to precision operation vand its purpose is to provide a cam operated circuit making and breaking device in which the duration of the closing of the circuit is sensibly constant over'long periods of time. The variation in a cam operated device is caused primarily by the very small change in the thickness of the contacts and other wearing parts such as the cam. The manner in which the wear and deterioration of the contact points is compensated for has just been described. However, in order to provide a Vernier adjustment of the instant at which the circuit is closed, means is provided for varying the width of the gap between contacts 42 and 44 when all of the contact arms are in their normal position of rest and with the cam 50 disengaged from either the arm I9 or the arm I8. To this end the clockwise pivotal movement 'of the arm I8 isl limited by suitable stop means in the form ofa threaded adjusting screw 63 suitably mounted on a bracket 65 fixed to the plate IIJ. By adjustment of screw 83 the opening of the gap between the contacts 42 and 44 may be varied to predetermine the distance the arm- I9 must travel before the contacts 42 andv44 ar engaged to close the circuit. Y'

I believe my invention capable of considerable modiication without departing from the spirit thereof, and accordingly I do not consider myself bound by the specic illustration hereinabove described except as set forth in'the appended claims.

Having thus described my invention, what I claim is:

l. Ina device of the class described, a pair of arms, conductive contact points on said arms, said -contact points being normally engaged, abutment means on respective arms, saidy abutment means being normally spaced, said arms being pivotally related to each other to effectv engagement-between said'abutment means, spring means for resillently biasing one of said arms towards the other, manually adjustable means operable on said other arm for predetermining the' length of travel between said abutment means, one of said abutment means comprising a non-conductive member, and means for causing periodic engagement of said abutment means comprisinga third arm pivotally related to said other arm and resiliently biased therefrom and including a cam for causing periodic oscillation of said third arm whereby said third arm is operative to periodically engage and oscillate said other arm.

2. In a device of the class described, a first arm, a second arm and a third arm, said arms being pivotally related with respect to each other, said second arm being intermediate said rst arm and said third arm, said first arm being resiliently biased towards said second arm, said third arm being resiliently biased away from said second arm, normally engaged contact points between said rst and second arms, normally spaced abutment means between said rst and second arms, normally spaced contact points between the second and third arms, and means for periodically oscillating said third arm to cause engagement between said contact points of said second and third arms, said engagement being operative to periodically oscillate said second arm to cause engagement between said abutment means of said rst and second arms whereby engagement of said contact points of said first and second arms is periodically interrupted in response to oscillation of said first arm.

3. In a device as set forth in claim 2, wherein said three arms are comprised of conductive material and wherein one of said abutment means between said rst and second arms comprises a non-conductive member.

4. In a device as set forth in claim 2, including manually adjustable means operable upon said second arm to predetermine the length of travel of the abutment means thereon towards the abutment means on said irst arm.

5. In a device of the class described, a first contact arm, a second contact arm and a third contact arm, each of said arms having electrical contact elements, said first and second contact arms having portions in overlapped relation and being mounted for pivotal movement in opposite directions about spaced points, said second arm being intermediate said first and third arms, each of said first and second arms having an abutment on the respective overlapped portions of said arms, one of said abutments being an insulating member, said abutments being adapted to be brought into non-conductive engagement, said third arm having a contact point for electrical engagement with said second arm, adjustable stop means for limiting the pivotal movement of said second arm, means for biasing said rst arm for pivotal movement in a direction to cause engagement of said contact elements on said first and second arms, and means for causing said third arm to pivot against said second arm where-by simultaneous pivotal movement of said rst and second arms about their respective pivot points will cause a difference in angular velocity of said overlapped portions of said rst and seccond arms and will cause engagement between said abutments and disengagement of said contacts carried by said arms.

6. In a device of the class described, a pair of Contact arms, each having portions arranged in overlapped relation, each of said arms having a contact point adapted for engagement with the other contact point, each of said arms also having an abutment adapted for engagement with the other abutment, said arms being mounted for pivotal movement about spaced points, a third Contact arm also mounted for pivotal movement and having a contact point adapted to be brought into conductive engagement with one of said rst mentioned pair of contact arms and means for causing said third contact arm to be moved t0- ward one of said pair of contact arms and to cause pivotal movement of the latter against the other of said pair of contact arms, whereby simultaneous pivotal movement of said pair of arms about their respective pivot points will cause a difference in angular velocity of said overlapped portions Of said pair of arms and will cause engagement between said abutments and disengagement of said contacts carried by said pair of arms.

HARRY A. COWARDIN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,255,846 Appel Feb. 12, 1918 1,352,266 Hirsch Sept. '7, 1920 FOREIGN PATENTS Number Country Date 610,838 France June 19, 1926

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