US2769051A - Switch - Google Patents

Description

Oct. 30, 1956 o. L. TAYLOR 2,769,051

ATTORNEY Oct. 30, 1956 O. TAYLOR l 2,769,051

5 WITNEssl-:s: INVENTOR Owen L.Toylor.

im WM mm ATTORNEY United States Patent titice 2,769,051 Patented Oct. 30, 1956 11 Claims. (Cl. 200-67) This invention relates generally to electric switches,

and more particularly to a simplified form of snap acting switch.

While many types of snap acting switches havebeen devised in the past, few, if any, commercially acceptable changes have been made in the switches which are used for many applications. For example, the ordinary wall toggle or pivoted handle switch used in house wiring has been stable for some time with respect to its design and size, so that there is little, if any, differential in the cost of these devices as made by different manufacturers. This invention in one of its specific aspects deals with improvements in a pivoted handle toggle type of switch, where the contacts of the switch are actuated with a snap action; however, the invention is not restricted to any particular form of switch, because certain features, such as the casing and terminal assemblies, are obviously of general application. I

One object of this invention, therefore, isto provide a commerically practical switch" of the type described which is of'simplied form andvreduced sizeand cost. Another object of this invention is to provide aI switch having a. novel contact structure which is's'usceptible of easy and economical manufacture. Another object of this invention is to provide a novel snap acting switch composed' of few parts, yet having an elicient and positive 'operating movement.

Another object of this invention is to provide electrical l apparatus, such as a switch, which is enclosed in an insulating casing, with terminals adapted for mounting on the casing in a novel simplied manner.

These and other objects of this invention will become more apparent upon consideration of the following detailed description 'of preferred embodiments thereof, when taken in connection with the attached drawings, in which:

Figure 1 is a central longitudinal section"viewyof la switch embodying this invention; i

Fig. 2 isV a top plan View of the switch shown inFig. l with the casing cover removed; Y i

Fig.- 3 is a side View of vthe switchshownffinl Fig. 1;

Fig. 4 is a bottom viewpf the switch lshown in Figs. 1

l to 3;

Fig. 5 is `a transverse cross-section View, of the vswitch shown in Figs. l to 4 and taken substantially on the line V-V o f Fig. 1;

Fig. 6 is a bottom View 'of a three-way type of switch if embodying this invention;

Fig. 7 is a top view of the switch shown in Fig. 6

with the cover and all movable operating parts withinA the switch casing removed;

Fig. 8 is a central longitudinal section view ofi-thv switch shown in Figs. 6 and 7 in completely assembled t form; and .I Y. Fig. 9 is an end view of the switch shown in Figs.

- This invention is preferably embodied in switches adaptyed to be mounted in a casing of insulating material, such as the casing 2 shown in Figs. l to 5. Such a switch casing 2V may include a bottom wall 4, end walls 6 and side walls 8, formed integrally of an insulating material, 'preferably of a molded insulating material. The top of the casing is left open and is adapted to be closed by a cover 10 which may be of any desired material, such as sheet metal, and may be secured to the casing in any desired way, preferably in the mannerv hereinafter disclosed in connection with the embodiment of the invention shown in Figs. 6 to 9 of the drawings. Y

The bottom wall of switch casing 2 interiorly of the casing is preferably formed with laterally spaced, longitudinally extending abutments 11, to form a longitudinally extending guide slot 12 intermediate the abutments 11, and located substantially centrally of the switch casing. A bridging contact 14 formed of a at strip-like portion of electrical conducting material, such as copper or brass, is adapted to be received edgewise in the slot 1 1, so as to be guided bythe slot for longitudinal sliding movement therein. 1

The switch illustrated in Figs. 1 to 5 of the drawing isin the form of a single pole switch having spaced stationary contacts 16 which are mounted in recesses in the bottom Wall 4 with each contact recess opening into the portions of the abutments 11 immediately above the stationary contacts, and into the base of the slot 12, so that the contacts 16 lie with their upper surfaces ushwith the base of slot 12. Each stationary contact 16 has 'a substantially right-angular terminal. portion 18 formed integral therewith, for receivinga terminal screw 20. It will be observed that each stationary contact lies in a recess or passage 22 which is open at each end to the outside of the switch casing 2, and that one 'side wall of the switch casing has spaced apart outer grooves 2,4 for receiving the terminalportion 18 of .each stationary contact. Also, by referring to Fig."4 of the drawing, it will be observed that the base .or bottom wall 4 of the switch casing is recessed at spaced points 26 on its outer surface, andthat the stationary contact passages 22 open at'their outer ends into these recesses 26, respectively.

' The purpose of this particular structure of the casing which cooperates with the stationary contacts 16 and their integral terminal portions 18, is to simplify the assembly of'these terminals and stationary contactswith the casing. Thus, it will be observed that the stationary contacts 16 and their integral terminal portions 18 may be assembled with the switch casing merely by sliding the stationary contactportions 16 into the open ends 'of vvtheir respective transverse passageways 22, from aV point adjacent` the side recesses l2 4 of the casing, until the terminal portions 18 lare seated on the base of their respective side recesses 24. It will be observed .that the inner end of each' stationary contact 16 is Vprovided with spaced integral securing 'tabs 28, and' that at'the fullyl inserted contact position, these tabs will llie in a re- 'cessv 26 provided on the outside ofthe bottom wall 4 of the casing, and the contacts 16 and their terminals 18 may then be securedly xed in operativeposition merely by bending the tabs 28 apart into engagement with the shoulders at the inner ends of recesses 26. Contacts 16 and their respective terminal portions 18 may be formed of any desired good electrical conducting material, such as copper or brass.

The bridging contact 14 may have' atits inner `edge rounded contact projections 30 which are spaced apart yto be located adjacent each end of the bridging conthereof with an operating projection 32, which is adapted to be received in one end of a coil compression operating spring 34, the otherend of which is adapted to be received in a hollow operating handle 36. Preferably, the operating handle 36 is of an insulating material, such as a molded insulating material, and has at each side integral pivot projections 33 which are adapted to be received in pivot depressions 40 provided in sidewalls 8 of the switch casing, and the handle pivot projections are held in place on the casing by engagement of ycover pivot depressions 42 therewith, when the cover is secured over the openside of the switch casing. Preferably, the pivot recesses 40 and 4 2 in the casing and cover are rounded to facilitate pivotal movement Vof the .operating handle 36. The operating handle may also have integraljlatral projections extending in opposite ldirec-j tionsl adjacent the inner end thereof, forming lateral abutments 44 for limitingmovement of the Vhandle in veach direction by engagement of these abutments with the casing abutments 11. v Y lIt' willnow be observed'that the the closed circuit position of the switch, as shown in Figfl of the drawing, the operating spring 34 being under compression and havingits line of action below handle pivots 38, acts to maintain the handle in its upper position wherein the yupper abutment'44 engages casing'abutments 11. At thisV position the spring 34 also acts to hold the bridgine contact 14 at its closed circuit position, and to urge it into engagement with the stationary contacts under predetermined contact pressure. If it is desired to open the switch, the operating handle 36 is moved in a clockwise direction about its pivots 38, thus changing the direction of the line of force of operating spring 34 relative t0 the bridging contact 14 until it finally arrives at a posi- `tion where the spring exerts aV force component in a direction to move the bridging contact upwardly, as viewed in Fig. l, with a rapid or snap action. In order to insure'operation of the switch despite failure of the operating spring, as might occur upon breakage of the spring, the innermost edge 4S of the handle recess is located so as Ato engage the adjacent edge of operating projection 32. on the bridging contact, to cam the bridging contact 14 in the corresponding direction. Thus, in opening the circuit, the lower edge 45 of the handle recess will engage the lower edge of operating projection 32 on the bridging contact to move it to an open circuit position, eventhough the operating spring 34 is inoperative.

.When the switch has been opened, it maybe closed by movement of the operating handle 36 counterclockwise to thus change the angle of the line of force 34 back 'toward the position shown in Fig. l where it will be effective to cause a rapid snap movement of the bridging" contact 14 to its closed circuit position. vAs previously mentioned at the closed circuit position, the actuating spring 34 not'only provides acomponent of force on the bridging contact 14 to hold it at its closed circuit position, but it also acts to hold the loperating handle 36 at`its closed position and to apply predetermined contactl pressure of the bridging contact 14 on the stationary .contacts 16. As a matter of fact,` operating spring 34 always appliesv pressure to the bridging contact. 14 in a direction against the bottom wall 4 kkof the switch casing so that actual engagement with the stationar'y contact 16 is in the form of a wiping action both during opening and closing movement of the bridging .contact under a predetermined pressure. All ofl these factors lare conductive to maintaining the contacts in good clean operating condition'7 and to preventing high heat losses and oxidation of the contact surfaces.V i

The fact that bridging contact 14 is mounted edgewise in a narrow slot 12 formed in the insulating material of theswitch casing, not only acts as a convenient guide for longitudinal movement of the bridging contact, vbut it willbe observed that the arc formed upon separationof the bridging contact from the stationary contacts is thus confined in this same narrow slot, so that the arc isclosely confined on three sides by relatively extensive surfaces of insulating material which act to rapidly cool and deionize the arc, and thus rapidly extinguish it. This particular arrangement enables the use of a much smaller separation of the contacts at the open circuit position than is possible with conventional switches of this type. The provision of the operating spring 34 in the hollow handle 36 is another factor which enables a switch constructed in accordance with this invention to be very much reduced in size and promotes more efiicient use of the available space. A switch thus embodying this invention may be made much smaller in size than has heretofore been possible and yet provide for eiiicient operation in the control of both alternating and direct current circuits.

The illustrative embodiment of the invention shown in Figs. 6 to 9 uses many of the features of the invention described above in connection with the illustrative ernbodiment shown in Figs. l to 5, but they are embodied in a form of switch known as a three-way type of switch for the control of a circuit from two different points. This embodiment of the invention is illustrated in the form of a switch also contained in a casing 46 of insulating material, such as a molded insulating material. The casing 46 being provided with an integral bottom wall 48, end walls 50, and side walls 52, with the top being left open to be closed by a cover 54 which may be of any, desired material, being shown here as of metal.

Inside switch casing 46, the bottom wall 48 is slotted and recessed to provide spaced narrow slots 56, 58 and 60, which are disposed in alignment and located sub' stantially on the central longitudinal axis of the switchcasing. Slots 58 and 60 are additionally formed with spaced transversely extending notches 62 in the bottom and side walls thereof.

A pair of stationary contacts 64, which may be identical with the stationary contacts 16 previously described,- are adapted to be mounted in appropriately formed recesses inthe casing with one contact being located at one end of the casing, and the other spaced therefrom at an intermediate point, having slot 68 interposed therebetween. Each of the stationary contacts 64 has an integral rightangularly disposed terminal portion 66, there being a recess 68 in one outer side wall of the casing for receiving the terminal portion 66 of the end stationary Contact 64, and a recess 70 in the outside surface of the other side wall 52 of the casing for receiving the terminal portion 66 of the intermediate stationary contact 64. Each of the terminal portions o f contacts 64 are provided with terminal screws 72.

The'principal difference in this embodiment of t e invention over that shown in Figs. l to 5, is in the incorpovration of a third contact comprising spaced stationary contact legs 7K4which are integral with a right-angular terminal portion 76 adapted to be received in a recess 7.7

provided in the same side wall of the switch casing as the terminal portion 66 of the end stationary contact 64. It will be observed that the stationary contacts 64 and 74 are mounted'in the switch casing 46 in substantially the same manner as the stationary contacts 16 previously described, in that the recesses formed interiorly in the casing for receiving these contacts are open at each end, with one end opening into the recesses 77 v(for contacts 74) or recesses 68 and 7) (for contacts 64) for receiving the terminal-portions of the respective contacts, and the other end opening into a recess 78 (for contacts 74),' or recesses 80 and 82 (for contacts 64) formed in the outer Vsurface of the'bottom wall 4S of the casing. The contacts 74 and 64 may thus be assembled with the switch Vcasing 46 in the same manner contacts 16 are assembled with casing 2 as described above, namely, the contacts may be simply inserted into their respective recesses from the end adjacent the' recesses for the terminal .portions thereof until the latter are rmly seated in their recesses, at whichtime integral securing `tabs 84 Aatthe outer end of each Contact will be located in the base recess 78,' 8 0 or 82 of the respective contacts, whereupon they vare secured in place simply by bending the securing tabs 84 relatively outwardly to engage shoulders formed at the inner ends of their respective recesses 78, 80 and 82.

The bridging contact 86 which is employed in this case is similar to the bridging contact 14 previously described, although somewhat different in form, having at the inner edge thereof tapered contact projections 88 at each end for engagement with the stationary contacts when the bridging contact is inserted edgewise in the slots 56, 58 and 60 at closed circuit position. The outer edge of bridging contact 86 is provided with a centrally located operating projection 90 adapted to be received in one end of a coiled operating spring 92, the other end of which is seated in a hollow bore 94 formed in the operating handle 96.

As in the previously described embodiment of the invention, the operating handle 96 is preferably formedof an insulating material, such as a molded insulating material, and also has at opposite sides integral pivot projec tions 98 adapted to be received in pivot recesses 100 formed in opposite side walls 52 of the switch casing. The handle is held with its pivot projections 98 located in the casing pivot recesses 100 with the operating spring 92 in compressed condition, by engagement of the cover 54 with the pivot projections 98 of the handle, and the cover in turn is secured to the casing in the manner shown in Fig. 9 of the drawing. Each end of the switch casing 46 is provided with a recess 102, having adjacent the open side of the casing opposed short tapered side walls 104, and the casing cover has integral securing tabs 106 which may be struck out of the material of the cover and which are initially straight so that they may be received in the narrow entrance to recess 102 adjacent the open side of the switch casing when the cover is placed over the open side of the casing, and thereafter the projections may be bent outwardly to securely fasten the cover in position.

The operating handle 96 is also provided with opposed projections 108 in this embodiment of the invention which acts as stops limiting pivotal movement of the handle in opposite directions. Also, the operating projection 90 of the bridging contact 14 is adapted to be engaged by the innermost edges of the handle bore 94 in case of failure of the spring, to obtain operation of the switch irrespective of whether or not the spring is operative, and for this purpose the operating projection 90 of the bridging contact 86 may have opposed depressions 110 formed therein.

The operation of the illustrative embodiment of the invention shown in Figs. 6 to 9 is very similar to that of the form of the invention previously described and shown in Figs. l to of the drawings, in that pivotal movement of the operating handle 96 in opposite directions acts through operating spring 92 to move the bridging contact 86 from one extreme position to the other with a rapid or snap action, while maintaining the bridging contact in engagement with the base of the casing and the stationary contacts under predetermined pressure, and effecting engagement and disengagement of the contacts with a wiping action under spring pressure. Also, the spring acts to hold the bridging contact 86 and operating handle 96 at their extreme positions.

At each extreme position of the bridging contact 86, it will be in bridging engagement with a pair of stationary contacts. Thus, at the upper position shown in Fig. 8, it bridges the upper stationary contact 74, and the intermediate stationary contact 64, whereas at the lower extreme position, it bridges the lower stationary contact 64 and the lower contact leg 74, to thus complete a circuit at each of its extreme positions. It can now be observed that the purpose of the transverse slots 62 is to introduce additional creepage distance between the stationary contacts of dissimilar polarity, and these slots also contribute to a more eicient arc extinguishing action, in that they provide reservoirs of fresh un-ionized air adjacent to th arc to aid in extinguishing it.

It will be noted that in both embodiments of the invention, provision has been made for easy assembly of the terminal and stationary contacts to the switch casing, with provision being made for this assembly by merely inserting the contacts in a slot provided in the casing, and merely bending integral tabs on each contact for securing it in operative position. Assembly of thev cover may also be facilitated in a similar way as illustrated in Fig. 9 of the drawings. Another space saving factor is the posi-y tion of openings for the terminal screws 20 (Figs. l to 5) and 72 (Figs. 6 to 9) in the adjacent side wall of the switch casing, so that the inner ends of these screws may extend into the interior of the switch casing, to thus permit use of a much narrower form of casing. Both embodiments of the invention also provide a construction wherein but a small separation of the contacts may be used, due to the ecient action of the narrow slot in extinguishing the arc formed when the switches are opened. Also considerable lateral space is saved due to mounting of the operating spring in the hollow operating handle.

While preferred embodiments of the invention have been described in detail above, as required by the Patent Statutes, it should be understood that this invention is not limited to these two particular forms of the invention but may be incorporated in whole or in part in other specic forms of switches or devices. Accordingly, it is desired that the invention be not limited to the herein described constructions, but that it be given a broader construction.

I claim as my invention:

l. A switch comprising, a casing of insulating material, at least one stationary contact supported in said casing on one wall thereof, a movable contact formed of a ilat, relatively thin rigid strip of electrical conducting material positioned with one side edge in slidable engagement with said one wall, guide means in said casing at opposite sides of said movable contact for guiding said movable contact for longitudinal sliding movement of said one side edge on said one wall into and out of engagement with said stationary contact, an operating handle pivotally mounted on said casing on an axis extending transversely of said;flat movable Contact, a compression operating spring engaging said handle and said movable contact under stress so that the force exerted by the spring longitudinally of the movable contact changes direction in response to movement of said handle in opposite directions to actuate said movable contact to open and closed circuit positions with a snap action and said movable con# tact is always biased into engagement with said one wall and provides predetermined Contact pressure when it engages the stationary contact.

2. A switch comprising, a casing of insulating material, at least one stationary contact supported in said casing on one wall thereof, a movable contact formed of flat strip material positioned with one side edge in engagement with said one wall, guide means in said casing guiding said movable contact for longitudinal sliding movement on said one wall into and out of engagement with said stationary contact, an operating handle pivotally mounted on said casing, an operating spring connected between said handle and said movable contact so that the force exerted by the spring longitudinally of the movable contact changes direction in response to movement of said handle in opposite directions to actuate said movable Contact to open and closed circuit positions with a snap action, said handle having spaced portions movable therewith into direct engagement with stop members in the casing to define the limits of handle movement, respectively, and each of said handle portions being spaced away from its stop member and the movable contact at one handle position but is positioned to directly engage the movable contact just prior to engagement with its stop to positively actuate the switch Yin the event the spring is notable to do so.

3`; A switch comprising, an elongated casing of-insulating material having an open side, longitudinally extending narrow slot means formed in the base of' said casing, spaced stationary contacts in the base of said-slot means, atleast one transverse groove formed in the basek of said slot means intermediate and spacedfrom said stationary contacts, an elongated relatively thin rigid bridging contact'bar received edgewise in said slot means to be supportedand guided therein for longitudinal sliding movement in the slot means into and out of bridging relation with respect to said stationary contacts, and` manually operable means for actuating said'bridging contact;

4; A switch comprising, an elongated casing of insulating material having an open side, longitudinally extending narrow slot means formed in the base of said casing, spaced stationary contacts in the base of said slot means, an elongated thin bridging contact bar received edgewise in said slot means for longitudinal sliding movement in the slot means into and out of bridging relation with respect to said stationary contacts, each of said stationary contacts comprising an angled piece of conducting material having a terminal leg and a contact leg, a slot extending transversely through said housing and opening into the base of said longitudinal slot means for receiving the contact leg of each stationary contact, said transverse slot being open at one side of the housing so that the terminal leg of each stationary contact will lie against saidone side of the housing, the other4 end of. said transverse slot opening into a depression in the outside surface of the housing base, and means on the outer end of the contact leg extending into said depression for preventing withdrawal of the contactV leg from said transverse slot, and manually operable means for actuating said bridging contact.

5. A switch comprising, a casing of insulating material having bottom and side walls and an open top, a transverse passageway through said housing adjacent the bottom wall for receiving from one end the Contact leg of a substantially right angled stationary contact member, with the other terminal leg thereof in engagement with the outside of one side wall of the casing, saidpassage- Way being open to the interior of said housing to expose said contact leg, and means for securing said. stationary contact member against withdrawal from said passageway.

6. A switch comprising, a casing of insulating-material havingbottom and side walls and an open top, a transu verse passageway through said housing adjacent theI bottom wall for receiving from one end thev contact leg of a substantially right angled stationary contact member, with the other terminal leg thereof inengagement with the outside of one side wall of the casing, an intermediate portion of said passageway being opento the interior of said housing to expose said contact leg, the other end of said passageway openingrinto a depression formed in the outside surface of the housing bottom wall, and means on the outer end of said contact leg extending into said depression for preventing withdrawal of the stationary contact from said passageway.

7. A switch comprising, a casing of insulating material having bottom and side walls and an open top, a transverse passageway through said housing adjacent the bottom wall for receiving from one end the contact leg `of a substantially right angled stationary contact member, withthe other terminal leg thereof in engagement with the outside of one side wall of the casing, an intermediate portion of said passageway being open to the interior of said housingto expose said contact leg, the other end of said passageway' opening into an enlarged depression formed in the. outside Vsurface of the housing bottom wall, and-bendable projections on the outer end ofV said contactu leg adapted to be bent into the depression after inv sertion ofsaid stationary contact to prevent withdrawal` in the slot means into and out of bridging relation with respect to said stationary contacts, an operating handle pivoted adjacent the open side of said casing, a compression spring engaging said handle and said movable contact. under stress so that' the force exerted by the spring longitudinally of the movable contact changes direction in response to movement of said handle in opposite directions to actuate said movable contact to open andclosed circuit positions with a snap action, and said movable contact is always biased into engagement with the base ofisaid slot and provides predetermined contact pressure when it engages said stationary contacts.

9. A switch comprising, a casing of insulating material, at least one stationary contact supported in said casing onone wall thereof, a movable contact formed of rigid hat strip; material positionedwith one side edge in slidable engagement with said one wall, guide means in said casing at opposite sides of said movable contact guiding said movable contact for longitudinal sliding movement onsaid one wall into and out of engagement with said stationary contact, a hollow operating handle pivotally mounted on said casing, an operating spring in said handle and connected between said handle and said movable contact, and said bore being enlarged at its end adjacent said movable contact in the direction of its movement so that the spring can flex longitudinally and the force eX- ertedL by. the spring longitudinally of themovable contactchanges direction in response to movement of said handle in opposite directions to actuate said movable contact to open and closed circuit positions with a snap action.

10. A switch comprising, a casing of insulating material, at least one stationary contact supported in said casing on one wall thereof, a movable contact slidably mounted on said one wall for movement into and out of engagement with said stationary contact, an operating handle pivotally mounted in said casing and having an operating portion extending through an opening in the wall of said casing opposite to said one wall, said handle having anl elongated hollow bore therein opening at the interior of the casing, a coil compression operating spring extending in said handle bore to engage the bottom of said bore at one end and having its other end engaging said movable Contact, and said bore being enlarged in the direction of its movement so that the spring can flex longitudinally and the force exerted by the spring longitudinally ofthe movable contact changes direction in response to movement of said handle in opposite directions to actuate said movable contact to open and closed circuit positions with a snap action.

l1. A switch comprising, a casing of insulating material, at least one stationary contact supported in said casing on one wall thereof, a movable contact slidably mounted on said one wall for movement into and out of engagement with said stationary contact, an operating handle pivotally mounted on said casing, an operating spring connected between said handle and said movable contact so that the force exerted by the spring longitudinally of the movable contact changes direction in response to movement of said handle in opposite directions to actuate said movable contact to open and closed circuit positionswith a snap action, said handle having spaced portions movable therewith into direct engagement with stop members in the casing to define the limits of handle movement, respectively, and each of said handle portions being spaced away from its stop member and the mov- 9 able contact at one handle position but is positioned to directly engage the movable Contact just prior to engagement with its stop to positively actuate the switch in the event the spring is not able to do so.

References Cited in the le of this patent UNITED STATES PATENTS 10 Winger Aug. 20, 1935 Zelov Apr. 19, 1938 Bryant et a1. Sept. 2, 1941 Cooper Aug. 8, 1950 Obenour Apr. 10, 1951 Dissinger Sept. 4, 1951 FOREIGN PATENTS Great Britain Feb. 12, 1943 Sweden July 27, 1943 Italy July 26, 1947

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