Патент USA US2409474код для вставки
Oct. 15, 194e. w. L.' BUTLER 2,409,472 ELECTRIC SWITCH Filed May 2.9, 1943 2 Sheets-Sheet l -Y i ’ Fig' /A "1' " «MMA w 11,*25’44 sê Av n., v f A ` , i ./ ¿Mun /fnen mm um”, ~\\`. H211'liHtu4»I>\uumlllllwlIMHHIIIINIIIlllllllllllillllllllllIlllllllllllllllllllllllilllllllwß 1‘- EN. n UW ' ` \\\\\\\‘. l5 " l i William - b3 ' ' Inventor: LaWPence'Butleï; _ 6J. A l-iig Attor‘nîg. A Oct. 15, 1946. w41.. BUTLER _ ` 2,409,472 ELECTRIG swITcH Inventor: Wìliiam Lawrence Butler; #@¿JMÄM t# His. 2,409,472 Patented Oct. 15, 1946 UNlTED STATES PATENT OFFICE 2,409,472 ELECTRIC SWITCH William Lawrence Butler, Schenectady, N. Y., as signor to General Electric Company, a corpora tion of New York Application May 29,A 1943, Serial No. 489,021 8 Claims. (C1. 200'--165) 1 My invention relates to electric switches, more pariicularly to switches especially designed to 2 ating shaft IE pivotally mounted in the sides of the casing and carrying interiorly of the casing closing position when subjected to severe vibra an actuating cam 22 and exteriorly of the casing an operating lever I8. rI‘he contact base I3 is tion or the shock of sudden impact. The inven preferably formed of molded plastic insulating tion is particularly applicable to control switches of relatively small capacity, such as limit switches, selector switches, and the like. The principal object of my invention is to Dro material and is bolted inside the casing I0 at the maintain a desired circuit-opening or circuit end opposite the operating shaft I6. Referring first to the switch operating mech anism, the operating shaft I6 is pivotally mount vide a new and improved simple, dependable and 10 ed in a pair of bearing'bosses i9 and 29 formed inexpensive electric switch of the shock-proof ype. It is a further object of my invention to pro 'in opposite walls of the casing IE). The shaft I6 extends through one wall of the casing and car ries on its outer end the operating lever I8 upon the end of which is mounted a roller 2| for en vide a switch contact structure arranged to min imize contact bouncing upon subjection to severe 15 gagement with any movable member whose mo tion it is desired to limit. Interiorly of the cas vibration or impact shock. ing ID and between the upright pillars I5 and It is a still further object of my invention to I5@ the operating shaft I6 has centrally connect provide a switch contact structure arranged to ed thereto the operating cam 22 upon opposite minimize relative sliding movement of the con sides of which is positioned a pair of helical tacts upon vibration thereof in engaging position. springs 23 and 24 surrounding the shaft I6. Ad It is still another object of my invention to pro jacent the bearing bosses I 9 and 20 and in spaced vide an electric switch contact structure arranged relation to the operating cam 22, the shaft I6 to minimize local Contact Vibration in response has connected thereto a pair of stop members 25, to impact shock. rline new and novel features of my invention 25 26 formed to provide axially extending projec tions 2l' and 28. respectively, preferably molded or cast integrally therewith, The stop members 25 and 255 are also provided with separate pairs complete understanding of the invention and a of radially spaced peripheral bosses 29 and 30, further appreciation of its objects and advan tages, reference should now he had to the follow 30 respectively. The bosses 29 and 30 are arranged for engagement. respectively, with narrow web ing detailed description taken in conjunction with portions 3l and 32 formed integrally with the cas the accompanying drawings in which Fig. 1 is a ing ID and extending between the bearing bosses plan view oi an electric switch embodying my in I9 and 20 and the pillars I5 and IECL, respectively. vention, the cover being partly broken away to The peripheral bosses 29 and 30 are positioned illustrate the switch structure; Fig. 2 is a cross to engage the webs 3! and 32 to limit rotational sectional view taken along the line 2_2 of Fig. movement of the operating shaft I6 and the cam l; Fig. 3 is a cross-sectional view taken along the 22. The helical springs 23 and 24 are each nro~ line 3-3 of Fig. l; Fig. 4 is an exploded perspec vided with angularly spaced radially extending tive View of certain parts of the switch operating end portions embracing the projections 21 and mechanism; Fig. 5 is an end elevation of the 2S, respectively. switch contact assembly; and Figs. 6 and 'I are Referring now more particularly to Figs. 2 and detailed views of certain portions of the switch 6, it will be observed that the actuating lever I4 actuating mechanism. is formed of a pair of parallel plates connected Referring now to the drawings, I have shown in parallel spaced relation having forked end my invention by way of illustration as applied to will be pointed out with particularity in the claims appended to this specification. For a more an electric limit switch mounted in a casing I0 having a cooperating cover II. To render the switch weatherproof, the cover II is preferably bolted to the casing and a gasket I2, of rubbery or the like material, is provided therebetween. In general, the switch comprises a contact as. scmbly mounted upon a suitable base I3, a switch actuating arm It pivotally mounted upon a pair of upright bosses or pillars I5 and |509 integrally formed interiorly of the casing I0, and an oper portions 35 and 36 mounted upon a transverse pivot pin 'ell'. The forked end portions of the plates 35 and` 36 carry therebetween a pair of cam follower rollers 38 and 39 arranged for en gagement with angularly spaced peripheral por tions of the operating cam 22. A helical com-- -pression spring Ita positioned between the pillars I5 and Iâa engages at one end the casing I0 and at the other end the forked end of the actuating lever I4, thereby to bias the roller 38 into con 2,409,472 3 tinuous following engagement with the surface of the cam 22. The earn 32 is formed with a pe ripheral depression 2id adjacent the roller 38 when the cam 22 and operating shaft I5 are in 4 and 5S are formed integrally with the spring strips 49 and 48, respectively, and extend later ally and in parallel spaced relation therefrom in the region of the switch contacts. their mid-positions normally maintained by the By reason of the manner of mounting the can helical springs 23 and 24, In this position a pe ripheral projection 22D on the cam 22 lies under, but does not normally engage, the roller 39. The projection 22h is not necessary to normal switch operation, but has for its purpose the limitation of movement of the actuating lever I4 due to vi bration or impact. The projection 22h is so ar tilever spring strips 48 and 49 described above, and because of the design of the spring strips themselves, their tendency to bounce open or to slide upon each other when subjected to vibra tion or shock in engaging position is substan tially eliminated. As described above, each pair oi spring strips extends in proximate parallel ranged that, without rotation of the shaft I6, the spaced relation through a relatively narrow slot in the upper side of the base I3. The ñxed ends depression 22a to open the switch contacts. 15 of each pair of cantilever springs are therefore The actuating lever I4 is pivotally mounted mounted upon the base in closely spaced relation upon the internal pillars I5 and I5a by means of with respect to the length of the spring strips. the transverse pin 3l, the opposite ends of which This brings the theoretical points oi fiexure of are seated in transverse slots 48 formed in the the springs very close together. rl‘he cantilever upper ends of the pillars. The slots 40 are pro 20 springs and the associated switch contacts, be vided with cover plates 4I and 47. which serve ing of substantially the same physical propor both to hold the transverse pivot pin 31 in op tion, tend to move sideways at substantially the roller 3B cannot move suiiiciently far out of the erating position in the slots 40 and to provide same speed in response to vibration or shock. fixed stops for the helical springs 23 and 24. As Since the points of flexure of the springs are very may be best observed by reference to Figs. 1 and 25 close together, the free ends of the springs swing 2, the cover plates 4| and 42 are each slotted from substantially the same point so that there longitudinally to provide a pair of up-turned is very little, if any, sliding movement between spring stops 43 and 44 of unequal length engag the contacts. It has been found that this tend ing opposite extending ends of the helical springs ency of the contacts to move together at sub 23 and 24. The stop plate 4I cooperates with .30 stantially the same speed thereby to avoid bounc the spring 23 and the stop plate 42 cooperates with ing of the contacts under vibration or shock is the spring 24, the stçps 43 and 44 upon each greatly enhanced by spacing apart the theoreti plate engaging adjacent sides of the angularly cal points of flexure at the fixed ends of the spaced extending ends of the associated spring. springs by substantially the same distance as the The actuating lever I4 has connected to each 35 centers oi’ gravity of the springs and connected plate 35 and 36, opposite the forked roller carry contacts. With such spacing a shock in any di ing end thereof, a wedge-shaped cam member rection will produce a turning in the same direc 45. As best illustrated at Figs. 2 and 6, the cam tion in both contact springs, thereby to produce members 45 are shown as blocks of molded in following rather than separating movement o_f sulating material bolted to the actuating lever 40 the contacts. If the points of flexure were spaced I4 and arranged for reversal in a manner here apart substantially farther than the centers oi inafter to be described, to select either a nor gravity, an impact along a line between the cen mally open or a normally closed position of the ters of gravity would produce opposite turning associated contacts. movements thereby to open the contacts. Referring now to the contact assembly, it will To further reduce the tendency of the contacts be observed that the insulating contact base I 3 to bounce apart under shock, the contact closing is of substantially box-like form and is slotted bias of each spring strip is sufliciently strong to on its upper side at 45 and 41 to provide for the permit it to follow its mate to the limit oi its suspension therein of a corresponding number of movement. In this connection, it will be noted pairs of contact elements. Each contact assem 50 that each pair of spring contacts is positioned in bly comprises a pair of cantilever spring strips recess between the side walls and a central 48, 49. Each contact spring has an outturned boss 69 of the contact base I3. The boss 6I) and ear at its base end bolted to the top side of the the side walls of the base provide stops 6I and base and to an associated terminal block 5B or E2 for limiting lateral movement of the spring 5I,‘as shown at Fig. l. Each pair of spring strips 55 strips. If, under shock or vibration, either strip extends through one of the slots 46, 4'I in proxi of a pair of contact strips is moved against its mate parallel spaced relation and preferably has bias and into engagement with the associated positioned between the fixed ends of the strips an stop, the closing bias of the cooperating spring insulating spacer 52. strip is sufficient to permit it to follow the iirst The cooperating cantilever spring strips 48 and 60 strip to the limit of its movement, thereby to 49 carry at their free ends a pair of cooperating maintain the contacts closed. The contact stops switch contacts 53, and 54, and are formed to SI and 62 formed upon the base I3 and the boss provide adjacent the contacts a pair of juxta 6I) are very close to the center of gravity of the posed carnming portions 55 and 55 for coopera associated contact elements, so that only slight tion with the wedge-shaped cam 45. Preferably, 65 lateral vibrational movement is permitted. By the spring strips 48 and 43 are tapered toward this close spacing of the contact stops, twisting their free ends to reduce the mass and inertia of motion of the contact springs under shock is the free ends thereby to reduce their vibration. prevented, thereby to eliminate local vibrational The spring strips of each pair are biased toward forces which may be set up by such twisting. each other to maintain the cooperating contacts 70 The use of the camming extensions 55 and 56 53 and 54 normally in engagement. The asso on the free ends of the contact strips for cooper ciated camming portions 55 and 56 are arranged ation with the wedge-shaped cams 45 has the to be slightly spaced apart when the contacts advantage that, when the contacts are separated are in engagement. In the illustrative embodi by insertion of the wedge 45, they move apart ment of the invention, the camming portions 55 75 With a rolling motion, as distinguished from the 2,409,472 straight-line motion which would result from insertion of the wedges` directly between the 6 stood that I intend in the appended claims to cover all such modiñcations as fall within the true spirit and scope of my invention. contact suriaces. In the illustrated embodiment What I claim as new and desire to secure by or" the invention, this rolling motion results» from Letters Patent of the United States is: a twisting of the spring strips 48 and 43 caused l. An electric switch comprising a base, a pair by exerting the separating force at only one side of cantilever spring strips mounted at one end oí the center lines of the strips. The rolling upon said base in substantially parallel spaced separating motion has a desirable tendency to relation and providing at their free ends coop discourage arcing upon separation of the erating switch contact portions and separate contacts. juxtaposed camming portions extending laterally As previously mentioned, any pair of contacts from said spring strips in parallel spaced relation, may be arranged to be normally open or normally said spring strips being biased to maintain said closed by merely reversing the position of the as~ contact portions in engagement and said cam sociated wedge-shaped cam 45 with respect .to the actuating lever I4. Referring particularly -to 15 ming portions in proximate spaced relation, and switch actuating means comprising a wedge Fig. 2, it will be observed that, if the cams 45 are shapedA cam movable from a position of disen gagement to a position between said camming in the drawings, the widest portion of the cam portions only, thereby to separate said contact will normally fall between» the camming portions 55 and 56 of the associated spring strips, thereby 20 portions with a torsional rolling action. 2. An electric switch comprising a base, a pair normally to maintain the contacts in open posi of cantilever spring strips mounted at one end tion. Aotuating movement of the lever I4 in a upon said base in substantially parallel spaced counterclockwise direction about the pivot pin relation, a pair of cooperating switch contacts 31, as viewed at Fig. 2, would then move the nar mounted upon the free ends of said spring strips, row portion of the wedge-shaped cams 45 between said spring strips being biased to maintain said the spring extensions 55 and 56 to permit closing contacts in engagement and being provided at of the contacts. As illustrated in the drawings, said free ends with juxtaposed camming portions both pairs of contacts are normally closed. V extending laterally from said strips in parallel It is believed that from the foregoing detailed spaced relation, and switch actuating means comdescription of the construction and arrange prising a wedge-shaped cam movable from a po ment of the various parts of my switch, its mode sition of disengagement to a position between said of operation will be easily understood. Brieiiy, camming portions only, thereby to separate said it may be noted that separation of the contacts contacts with a torsional rolling action. may be effected by either clockwise or counter 3. An electric switch comprising a base, a pair clockwise movement of theV operating shaft I6, as of tapered cantilever spring strips mounted at viewed at Fig. 2. For example, if the shaft I6 their wider ends upon said base at points proxi is moved in .the clockwise direction, the spring mately spaced in relation to the length of said stops 43 hold one end of each of the helical spring strips and extending in substantially par springs 23 and 24 stationary and the projections 21 and 28 on ythe stop members 25 and 25, respec 40 allel spacedV relation, a pair of cooperating switch contacts mounted upon the narrow free ends of tively, move the opposite ends of the springs in a said spring strips, said spring strips being pro clockwise direction against the spring restraining vided at said free ends with juxtaposed camming force. Clockwise movement of the operating shaft is limited by engagement of the upper pe portions and being biased to maintain said con ripheral bosses 29 and 30 on the stop members tacts in engagement and said camming portions 25 and 26 (as viewed at Fig. 2) with -the webs 3| in proximate spaced relation, fixed vstop means and 32, respectively, of the casing HJ. The cam adjacent said free ends of said spring strips for limiting contact disengaging lateral movement 22, moving in a clockwise direction with the opu of each of said spring strips, the spacing between era-ting shaft I6, moves the roller 38 on the ac-tu ating lever i4 out of the slot 22a thereby to move said stop means and the adjacent spring strip being substantially equal to the spacing between the actuating lever i4 in a counterclockwise di said spring strips, and switch actuating means rection, as viewed at Fig. 2, against the bias of the spring 14a. Counterclockwise movement of comprising awedge-shaped cam movable from the actuating lever I4 moves the wide portions a position of disengagement to a position between of the wedges 45 between the camming exten saidv camming means to separate said contacts. turned around 180° upon a vertical axis as viewed sions 55 and 56 of the spring strips to separato _ the contacts. As soon as'the operating lever I2 is released, the helical biasing springs 23 and 24 return the operating shaft I6 to its normal midñ position as shown in the drawings. Upon counterclockwise movement of the opern ating shaft I6, as viewed at Fig. 2, an entirely to vibration and impact shock comprising a base, a pair of cantilever spring strips mounted at .one end upon said base at points proximately spaced in relation to the length of said spring strips and similar action takes place, except that the spring 4. .An electric switch adapted for subjection extending therefrom in substantially parallel spaced relation, a pair of cooperating switch con tacts mounted upon the free end of said spring Stops 44 serve Ito hold stationary theassociated ends of the helical springs 23 and 24, while the projections 21 and 28 move the other ends of the springs in a counterclockwise direction. Counter~ clockwise movement of the cam 22 also raises the roller 38 out of Ithe slot 22a and produces counter clockwise movement of the actuating lever Mi to strips, said spring strips being provided at said free ends with juxtaposed camming portion and separate the contacts. spring strips, the spacing between said stop While I have shown only one preferred embodi ment of myinvention by way of illustration, many other modifications will occur to those skilled in the art and I, therefore, wish to have it under 75 means and the adjacent spring strip being sub stantially equal to the spacing between said spring strips, the contact engaging bias of each of said spring strips `being suflicient to permit it being biased to maintain said contacts in engage ntent and said camming portions in proximate spaced relation, fixed stop means adjacent said .free ends of said spring strips for limiting contact disengaging lateral movement of each of said 2,409,472 7 8 to maintain following engagement with the co torsionally to stress said spring strips and to operating spring strip at least until said cooperat ing spring strip engages its associated stop means when subjected to vibration or impact, and switch actuating means comprising a wedge separate said contacts with a rolling action. 7. An electric switch comprising a slotted base, a pair of cooperating switch elements each in cluding a cantilever spring strip carrying at its shaped cam movable from a position of disen free end a switch contact, said pair of spring gagement to a position between said camming means to separate said contacts. 5. An electric switch comprising a base, a pair of cantilever spring strips mounted at one end upon said base at points proximately spaced in relation to the length of said spring strips and strips extending in substantially parallel spaced relation through a slot in said base and be ing 'mounted upon said base at points spaced by substantially the same distance as the centers of gravity of said switch elements, a pair of juxtaposed camming extensions projecting later extending in substantially parallel spaced rela ally from said spring strips adjacent said con tion, a pair of cooperating switch contacts tacts, said spring strips being biased to mainmounted upon the free ends of said spring strips, 15 tain said contacts in engagement and said cam said spring strips being provided at said free ming extensions in proximate spaced relation, ends with juxtaposed camming extensions pro fixed stop means adjacent said free ends of said jecting laterally from said strips adjacent said spring strips for limiting contact separating lat contacts and being biased to maintain said con tacts in engagement and said camming exten sions in proximate spaced relation, fixed stop eral movement of each of said spring strips, the 20 spacing between said stop means and the ad means adjacent said free ends of said spring strips for limiting contact disengaging lateral move ment of each of said spring strips, the spacing between said stop means and the associated spring 25 strip being substantially equal to the spacing between said spring strips, a switch actuating lever carrying at one end a wedge-shaped cam movable from a position of disengagement to a jacent spring strip being substantially equal to the spacing between said spring strips, and switch actuating means comprising a Wedge-shaped cam movable from a position of disengagement to a position between said camming extensions to sep arate said contacts. 8. An electric switch comprising a slotted base, a pair of cooperating switch elements each in cluding a tapered cantilever spring strip carry position between said camming means to separate 30 ing at its narrow free end a switch contact, said said contacts, a forked cam follower mounted spring strips extending through a slot in said upon the opposite end of said switch actuating base in substantially parallel spaced relation and lever, and a rotatable operating cam disposed in being mounted at their wider ends upon said base operative relation with respect to said forked cam at points spaced by substantially the same dis follower for actuating said switch actuating lever, tance as the spacing between the centers of said forked cam follower providing a pair of gravity of said switch elements, a pair of juxta members disposed adjacent angularly spaced posed camming extensions projecting laterally points of said operating cam thereby positively from said free ends of said spring strips, said to maintain continuous following relation there spring strips being biased to maintain said con between. 40 tacts in engagement and said camming exten 6. An electric switch comprising a base, a pair sions in proximate spaced relation, fixed stop of cooperating switch elements each including a means adjacent said free ends of said spring cantilever spring strip carrying at its free end a strips for limiting contact separating lateral switch contact, said spring strips extending from movement of each of said strips, the spacing be said base in substantially parallel spaced rela 45 tween said stop means and the adjacent spring tion and being mounted at points spaced by sub strip being substantially equal to the spacing stantially the same distance as the centers of between said spring strips, the contact engaging gravity of said switch elements, a pair of juxta bias of each of said spring strips being surfi posed camming extensions projecting laterally cient to permit it to maintain following engage and in parallel spaced relation from said spring 50 ment with the cooperating spring strip at least strips adjacent said contacts, said spring strips until said cooperating spring strip engages the being biased to maintain said contacts normally associated stop means, and switch actuating in engagement and said camming extensions in means comprising a wedge-shaped cam movable proximate spaced relation, and switch actuating from a position of disengagement to a position means comprising a wedge-shaped cam movable 55 between said camming extensions to separate said from a position of disengagement to a position contacts. between said camming extensions only, thereby WILLIAM LAWRENCE BUTLER.