US2549794A - Control switch - Google Patents

Description

Apri 24, 951. s. L. FRANK 2,549,794

' CONTROL SWITCH Filed Feb. 2s, 194s Patented Apr. 24, 1951 CONTRL SWITCH Stanley L. Frank, Beaver, Pa., assigner to Westinghonse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 28, 1948, Serial No. 11,940

(Cl. 20D-159) 14 Claims. 1

This invention relates to electric switches generally, and more especially to small control switches of the rotary and push-button types.

The principal object of this invention is to provide a novel simplified switch design composed of relatively few parts so as to be inexpensive to manufacture.

Another object of this invention is lto provide a novel basic switch design which may be assembled with either a rotary or push-button switch operating means.

Another object of this invention is to provide in a rotary type of electrical control switch, novel 1means -for causing actual engagement and disengagement of the contacts in a direction at an angle to the plane of ltheir rotary movement.

Another object of this invention is to provide a push-button switch having a novel arrangement of voperating button and movable contact so that either of two pairs of stationary contacts may be bridged by said'movable Contact.

Another object of this invention is to provide novel form and mounting of stationary contacts on a switch base.

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 drawing; in which,

Figure 1 is a substantially central sectional view through a rotary selector switch embodying this invention;

Fig. 2 is a substantially central sectional View throughl a push-button type switch embodying the invention and having most of its parts identical with parts of the selector switch shown in Fig. l;

Fig. 3 is a top view of the switch base shown in Figs. 1 and 2;

Fig. 4 is a bottom view of the switch cover shown in Figs. l and 2, with the selector switch handle vof Fig. lin-place;

Fig. .5 is an end view of the switch shown in Fig. l;

Fig. -6 is a bottom view o-f the push button employed in the switch shown in Fig. 2; and

Fig. 7 vis a partial sectional view of the switch vbase taken substantially on the line VII-VII of Fig. 3. i

In accordance with this invention, two types of switches are provided, namely, (l) a rotary selector type of switch, and (2) a push-button type of switch, with both switches employing identical parts .and .with the only parts individual to lthe two switches being the operating members 2 themselves, and in vthe case of the push-button switch a return spring `for the push button. As shown on `the drawing, a switch base 2 is employed in both types of switches, being made of an insulating material, preferably of a molded insulating material. Switch base 2 on the under side Vthereof is provided with a boss 4 at each Vend thereof, which has an opening extending laterally therethrough for receiving a mounting screw yor the like. The under side of switch base 2 also has a central boss i5 for a purpose which will be described.

The upper side of switch base 2 is provided at veach corner thereof with longitudinally extending recesses 8 in the upper surface for the reception .of angled contact strips lil, respectively. Each .of the contact strips l0 are preferably formed from a strip of good electrically conducting material, such as copper or brass with the strip bent at right angles intermediate its ends. Each strip Ii) thus has a relatively narrow contact leg .l2 vadapted to lie in one of the recesses .3, and a relatively wide terminal leg it extending downwardly at right angles t0 the contact `leg. I2 along the adjacent end of switch base 2. rlhe terminal leg I4 of each contact strip tu has a threaded opening for the reception of a terminal screw It for securing a wire conductor thereto. When terminal screws l@ are fully taken up, the inner ends thereof are located in krecesses i8 formed in switch base 2. It will be obs-erved that each boss il of switch base 2 has an integral shoulder 20 adapted to overlie a portion of terminal leg lli of e'ach of the contact strips.

It will be app-arent that when contact strips I6 are mounted on switch base 2 in the manner illustrated on the drawing, that shoulder 2|] prevents accidental `withdrawal longitudinally of the contact strips, while sidewise movement is, Vof course, prevented by the sides of each recess 8 and transverse removal in an upward direction is prevented by engagement of terminal screws i6 with .the upper wall of recesses I3. Of course contact strips lil can be readily removed or placed in operative position when terminal screws l 6 are unscrewed an amount sufficient to clear the top walls of their respective recesses I8. However, when the contact strips i@ are assembled in the base 2 as shown in Fig. 3, it will be apparent that they are held in place merely by the intertting coopera-tion of parts of the strips and terminal screws i6 `with the specific formation of switch base 2, and have no other securing means. Each recess 8 in Aswitch base 2 is illustrated as having a laterally outwardly extending offset portion 22; and if desired, each Contact strip may have a similarly shaped projecting position to enter these offset portions 22 to further interlock the contact strips with the switch base.

A cover 24 also of insulating material, preferably oi a material similar to that comprising base 2, is provided for the top of base 2 and has transverse end openings 26 adapted to be in alignment with the openings in bosses 4 of the switch base for the reception of securing thimbles 28 which are spun over at their ends to secure the cover 24 and base 2 together. In mounting the switch mounting screws or bolts may be inserted through thimbles 38 to secure the switches to any desired support. Switch cover 24 is provided with a substantially centrally located opening 3| for the reception of either (l) a rotary operating handle having a bridging contact 32 mounted on the inner end thereof, or (2) a push button operating handle 34 which has the same bridging Contact 32 operatively mounted on the inner end thereof.

Considering rst vthe selector type switch, shown in Fig. 1, it will be apparent that in addition to the outer handle portion of the switch operating member 3G, it has a circular portion 36 which relatively closely ts in cover opening 3|, and inwardly of this it has a further enlarged flange portion 33 adapted to seat against a shoulder 39 provided on the inner surface of cover 24. Flange 3S on handle 36 is provided at opposite sides with radially extending stop lugs 4) which are adapted to be received in cut-out portions 42 and 44 at opposite sides of cover opening 3l beneath cover shoulder 39, to thus form inwardly radially extending stop lugs 45 and 48 integral with cover 24. It will be apparent that shoulder 39 of the cover limits outward movement of handle 3d relative to the switch base and its cover, and that stop lugs 49 on the handle cooperate with stop lugs 46 and 48 on the cover to limit the rotation of handle 39 to positions defining two different closed circuit positions of the switch.

Inwardly of flange 38, handle 33 has a short portion e very much reduced in area which receives a pivot pin 54 which is secured in handle 3i) as by being molded therein, and which has a square portion 52 located near reduced portion 56 of handle 3E. Pivot pin 54 has its inner end received in an opening provided in central boss 6 of the base to thereby form one bearing for rotation of the operating handle, the other bearing comprising opening 3| in cover 24.

Bridging contact 32 preferably comprises a strip of resilient conducting material, such for example, as a copper alloy, such as phosphorbronze or beryllium-copper alloy having substantially midway between its ends a square opening through which pivot pin 54 may be inserted tcreceive therein the square portion 52 of the pivot pin to thus nonrotatably mount bridging contact 32 on operating handle 33. Preferably the outer contacting ends 53 of bridging contact 32 ar formed substantially V-shaped in cross section as by a bending operation to form line contacting portions and to facilitate operation of the switch in a manner hereinafter described.

It will be observed in Fig. 3 that each contact strip i6 has a cut-out portion 58 at the inner side thereof for receiving one end of a cam portion 66 formed integral with base 2 and extending into the adjacent recess 8. Cam projections at each end of switch base 2 extend towards each other substantially along the segment of an arc, but have their adjacent ends spaced apart by a slot E2 formed in the material of switch base 2. Slots 64 are also formed in switch base 2 and extend substantially at right angles to slots 62, with both slots thus sen/ing to increase the creepage distance between adjacent contact strips, and with slots 52 having the additional function of dening a mid position of the switch where all circuits are open.

An important feature of the switch comprising this invention which has thus far been described, is that the parts may be readily assembled merely by laying them in place without any need for additional securing means. The manner in which contact strips lll may be laid into the recess formations in switch base 2 and retained therein against accidental displacement beforecover 24 is applied, has already been explained above. In

assembling the cover and handle structure to the base, it is apparent that handle 33 may be merely laid into the cover when the latter is at an inverted position relative to that shown in Fig. 1, and flange 33 will automatically butt up against shoulder 39 on the cover. Bridging contact 32 may then be slipped over pivot pin 54 and angularly adjusted until its square aperture fits over the square portion 52 of pivot pin 54, and all that is necessary then is to place switch base 2 with its contact strips assembled on the cover and secure them together with thimbles 28.

Preferably, bridging contact 32 is initially bowed as shown in Fig. 2, and the dimensions of the parts are arranged to be such that when cover 24 is assembled with switch base 2 with a selector handle 33 in the cover, that the step of securing the cover and base together will cause a stress to be set up in bridging contact 32, and as shown in Fig. 1, the bridging contact may be stressed sufliciently to substantially flatten it.

The selector switch is shown in Fig. 1 at its intermediate open circuit position. At this position the contact ends 56 of bridging Contact 32 lie intermediate adjacent cam projections 6U on the base directly above slots 62. Upon rotation of operating handle 3Q in either direction, certain initial resistance is encountered due tothe necessity of camming the outer V-shaped ends 56 of the bridging Contact upwardly on to the top of a cam projection 60. Since deflection of the outer ends of bridging contacts 32 in this manner further stresses the bridging Contact, the initial resistance encountered for this action will be readily appreciated. Upon continued movement or operating handle 3i: in the same direction, the contact portions 56 of bridging contact 32 ride along the tops of cam projections 6i) until the outer ends of these projections are reached, at which time the contact portions 55 of the bridging Contact 32 will snap down onto their respective contact legs I2 of contact strips IIJ. This will thus dene one closed circuit position of the switch and movement in the same direction will be stopped by engagement of stop lugs 46 with one side or the other of stop lugs 46, 43 formed in the switch cover. To open the circuit, operating handle 3 is rotated opposite from the direction of switch closing movement and, accordingly, the first thing which occurs is that the contact portions 56 of bridging contact 32 are caused to ride up on the outer ends of their respective adjacent cam projections 66. This causes the contact portions 56 of the bridging contact to break the circuit on contact'legs I2 of each contact strip at a point on the upper sur- -in Fig. l.

Aface of such contact legs so that the arc is coniined to metal surfaces, and is not dragged over an edge of the contact strip or over any portion oi the insulating material.

While the selector switch shown on the drawing lis provided with means dening an intermediate open circuit position, it will be apparent that this feature may be omitted if desired and that adjacent cam projections 60 can be made continuous without any space between their adjacent ends.

Referring to Fig. 2 of the drawing, it is apparent that most of the parts, comprising switch base 2 with its contact strips l0, switch cover 24 and bridging contact 32, employed for this push-button type of switch are identical in every respect with the parts used for the selector switch shown in Fig. 1. v these parts are identified with the same reference numerals throughout, and a detailed description will not be repeated. A

Instead of selector operating handle 30, there is provided in the embodiment of the invention shown in Fig. 2-a push-button operating handle 3d having an inner flange 6B projecting therefrom to engage cover shoulder 39 at the outer position of push button Sli. It will be observed (Fig. 6) that flange 65 of push button 34 has opposed cut-out portions 68 adapted to closely t stop lugs i6 and 48, respectively, of the cover structure to thus slidably but non-rotatably mount push-button handle 3ft in the cover structure. At is inner end, push button 34 has a short shaft section secured therein, as by `molding or the like which is square in section so as to be received in the square opening provided in bridging contact 32. A coil compression spring .'52 reacts between a recess 14 in the base and bridging contact 32 to not only bias thebridging Contact and push button 3d to their outer circuit positions, but also to hold bridging contact 32 assembled with push button 34.

It will be apparent that the vpush-button switch shown in Fig. 2 may be assembled in substantially the same manner as the selector switchshown contact strips are identical in all respects and are assembled in exactly the same manner as previ- `ously ldescribed in connection with the selector switch shown in Fig. 1. Moreover, push button 311 vmay be inserted in cover opening 3l lfrom the under side thereof in the same manner operating handle 3i] is assembled, and then bridging contact 32 can be slipped over the square shaft portion 'l0 which extends inwardly of push -button 34. Coil compression spring 12 may then be slipped over the outer end of shaft and the switch base 2 may then be placed on thecover and the two secured together in the same manner described above in connection with Fig. 1. It will be observed that bridging contact 32can be mounted on square shaft 'le in either of two different positions substantially 90 apart, so that when handle 3d -is` depressed, the bridging contact will complete the circuit between the correspondingly diagonally l opposite contact strips lll. o I o l In order to close the circuit employing the push button switch shown in Fig. 2, it is merely necessary to manually depress button 34 to move the contacting ends 55 of the bridging Contact into engagement with the corresponding contact strips lil. It will be observed that contact pressure is obtained by the bridging contact 3,2 itself, because it will bend longitudinally after In order to avoid repetition,

As a matter of fact, the base 2 and being brought into engagement with stationary contact str-ips I0. Furthermore, longitudinal bending of bridging contact 32 in closing the circuit results in a desirable wiping action of the contacts. When the push button 34y is released, spring i2 moves the `button back to its *upper open position as shown in Fig. 2.

It isbelievedapparent from the foregoing that this invention provides a basic switch design employing a single switch base carrying stationary contacts, switch cover and bridging contact structures which can be used for two different tylQeS of switches such as the selector and push-button type hereindescribed and illustrated. It is only necessary in either case to mount the appropriate operating member in Cover 24, and drop on bridging contact 32, with the return spring i2 being additionally required only in the case of the push-button switch. The switch cover and base may then be secured together and the switches are then ready for operation.

Having described preferred embodiments of this invention in accordance with the patent statutes, it is desired that this invention be not limited to the particular structures described herein, inasmuch as it will be apparent to persons skilled in the art that many changes and modifications may be made in these particular structures without departing from the broad spirit and scope of this invention. Accordingly, it is desiredthat the invention be interpreted as broadly as possible and that it be limited only as required by the prior art.

I claim as my invention:

l. A switch adapted for use with a rotary or a push-button type of operating handle, comprising, a base of insulating material, contacts mounted on one side of said base at angularly spaced points about a recess in said one side, a cover for said one side of said case having a cavity overlying said contacts and having an aperture aligned with said recess for receiving a rotary or a push button type of operating handle, said cover having at least one pair of abutments spaced angularly about said aperture an amount corresponding to the angular spacing of an adjacent pair of said fixed contacts so as to be cooperable with means on a rotary type operating handle to limit rotation thereof to define spaced closed circuit positions, and so as to also be cooperable with means on a push-button type of operating handle to prevent rotation thereof while permitting longitudinal sliding thereof.vv v I o 2. A switch adapted for use lwith a rotary or a push-button type of operating handle, comprising,a base of insulating material, contacts mount- .ed on one side of said base at angularly spaced points about a recess in said one side, a cover for said one side of said base having a cavity' overiying said contacts andy having an aperture aligned withsarid irecess for receiving a rotary or apush button type of operating handle, a longitudinally bowed bridging4 contact of a resilient lconducting material located inl said cavity .for bridging an opposed pair of said contacts, an operating handle movably mounted in said aperture and having an inner flange portion adapted to engage an abutment on said cover about said 0 aperture to limitoutward movement of said 'push-button type of operating handle, comprising a base of insulating material, said base having at one side a central recess and a plurality of contact recesses spaced about said central recess, each of said contact recesses extending to the adjacent edge of said base, angled contact members adapted at operative positions to have one leg thereof seated in one of said contact recesses with the other leg thereof in engagement with said adjacent edge of the base, spaced abutments on said base adapted to overlie a portion of the outer sideV of said other leg of each contact member, respectively, to prevent outward movement of the contact members, a cover for said one side of the base to prevent lateral movement of said contact members from their respective contact recesses when said cover is secured to the base, said cover having a cavity overlying portions of said contacts for receiving a movable bridging contact, and said cover also having an aperture aligned with said central base recess for receiving a rotary or a push button type of operating handle for operating said bridging contact.

4. A switch adapted for use with a :rotary or a push-button type of operating handle, comprising a base of insulating material, said base having' at one side a central recess and a plurality of contact recesses spaced about said central recess, each of said contact recesses extending to the adjacent edge of said base, angled contact members adapted at operative positions to have one leg thereof seated in one of said contact recesses with the other leg thereof in engagement with said adjacent edge of the base, spaced abutments on said base adapted to overlie a portion of the outer side of said other leg of each contact member respectively, to prevent outward movement of the contact members, a cover for said one side ofthe base to prevent lateral movement of said contact members from their respective contact recesses when said cover is secured to the base, said cover having a cavity overlying portions of said contacts for receiving a movable bridging contact, and said cover also having an aperture aligned with said central base recess i'or receiving a rotary or a push button type of operating handle for operating said bridging corn tact, a terminal screw on said other leg of each contact member, and said base having recesses in said adjacent edge thereof for receiving said terminal screws respectively, lor preventing lateral outward movement of said contact members when said cover is not in place.

5. A rotary selector switch, comprising, a base of insulating material, contacts mounted on one side of said base at points spaced angularly about a pivot recess in said one side of the base, a coverl for said one side of the base having a cavity overlying said contacts and having an aperture aligned with said pivot recess, an operating handle mounted for rotation in said aperture and recess, a bent bridging contact of resilient material mounted for rotation with said handle in said cavity with the convex side of said bridging contact adjacent said handle, and cooperating means on said handle and cover acting when said cover is mounted at operative position to hold said handle at a longitudinal position wherein said bridging contact is stressed at least when it is at a contact bridging position.

6. A rotary selector switch, comprising, a base of insulating material, contacts mounted on one side of said base at points spaced angularly about a pivot recess in said one side of the base, a cover for said one side of the base having a cavity overlying said contacts and having an aperture aligned with said pivot recess, an operating handle mounted for rotation in said aperture and recess, bridging contact means mounted on the inner end of said handle in said cavity and having at least the contacting portions thereof biased into engagement with opposed contacts on said base when said bridging means is at a closed circuit position, and integral cam portions on said base at the side of each of said base contacts in the path of circuit opening movement of said bridging means so as to move at least said contacting portions laterally in response to initial circuit opening rotation of said operating handle.

7. A rotary selector switch, comprising, a base of insulating material, contacts mounted on one side of said base at points spaced angularly about a pivot recess in said one side of the base, a cover for said one side of the base having a cavity overlying said contacts and having an aperture aligned with said pivot recess, an operating handle mounted for rotation in said aperture and recess, bridging contact means mounted on the inner end of said handle in said cavity and having at least the contacting portions thereof biased into engagement with opposed contacts on said base when said bridging means is at a closed cir-- cuit position, and integral cam portions on said base at ythe side vof each of said base contacts in the path of circuit opening movement of said bridging means so as to move at least said contacting portions laterally in response to initial circuit opening rotation of said operating handle, and adjacent cam portions being spaced apart to receive one of said contacting portions at an open circuit position of said switch for releasably holding the switch at such position.

8. A rotary selector switch comprising, a base of insulating material, contacts mounted on one side of said base at points spaced angularly about a pivot recess in said one side of the base, a cover for said one side of the base having a cavity overlying said contacts and having an aperture aligned with said pivot recess, an operating handle mounted for rotation in said aperture and recess, bridging contact means mounted on the inner end of said handle in said cavity and having at least the contacting portions thereof biased into engagement with opposed contacts on said base when said bridging means is at a closed circuit position, said base contacts being notched on the side thereof in the path of circuit opening movement of said bridging means, and integral cam portions on said base in said contact notches, so as to move at least said contacting portions laterally in response to initial circuit opening rotation of said operating handle.

9. A rotary selector switch comprising, a base of insulating material, contacts mounted on one side of said base at points spaced angularly about a pivot recess in said one side of the base, a cover for said one side of the base having a cavity overlying said contacts and having an aperture aligned with said pivot recess, an operating handle mounted for rotation in said aperture and recess, resilient bridging contact means having an intermediate opening of irregular shape to non-rotatably receive a complementary shaped inner shaft portion on said operating handle, and cooperating circular abutment means on said cover and operating handle for holding said handle at a longitudinal position wherein said bridging contact means is held stressed between an abutment on said handle and said base contacts when said cover is mounted in phase and said handle is at a closed circuit position.

10. A push-button switch, comprising a base of insulating material, contacts mounted on one side of said base at angularly spaced points about a recess in said one side, a cover for said one side of said base having a cavity overlying said contacts and having an aperture aligned with said recess for slidably but non-rotatably receiving a push button, said push button having an inner extension which is irregular in cross section, a

longitudinally bowed bridging contact of a resilient material, having an intermediate opening of a shape complementary to the shape of said extension to non-rotatably receive said extension, and resilient means reacting between the bottom of the recess in said base and said bridging contact to hold said bridging contact on said extension and bias it and the push button to an outer open circuit position.

11. A push-button switch, comprising a base of insulating material, contacts mounted on one side of said base at angularly spaced points about a recess in said one side, a cover for said one side of said base having a cavity overlying said contacts and having an aperture aligned with said recess for slidably but non-rotatably receiving a push button, said bush button having an inner extension which is regular but noncircular in cross section, a longitudinally bowed bridging contact of a resilient material having an intermediate opening of a shape complementary to the shape of said extension to nonrotatably receive said extension at a plurality of different relative angular positions corresponding to the angular position of different opposed base contacts, and resilient means reacting between the bottom of the recess in said base and said bridging contact to hold said bridging contact on said base and bias it and the push button to an outer open circuit position.

12. A switch comprising a base of insulating material, said base having at one side a central recess and a plurality of contact recesses spaced about said central recess, each of said contact recesses extending to the adjacent edge of said base, angled contact members adapted at operative positions to have one leg thereof seated in one of said contact recesses with the other leg thereof in engagement with said adjacent edge of the base, spaced abutments on said base adapted to overlie a portion of the outer side of said other leg of each contact member respectively, to prevent outward movement of the contact members, a cover fo-r said one side of lthe base to prevent lateral movement of said contact members from their respective contact recesses when said cover is secured to the base, said cover having a cavity overlying portions of said contacts for receiving a movable bridging contact, and said cover also having an aperture aligned with said central base recess, a terminal screw on said other leg of each contact member, and said base having recesses in said adjacent edge thereof for receiving said terminal screws respectively, for preventing lateral outward movement of said contact members when said cover is not in place.

13. A switch comprising a base of insulating material, said base having at one side a central recess and a plurality of contact recesses spaced about said central recess, each of said contact recesses extending to the adjacent edge of said base, angled contact members adapted at operative positions to have one leg thereof seated in one of said contact recesses with the other leg thereof in engagement with said adjacent edge of the base, spaced abutments on said base adapted to overlie a portion of the outer side of said other leg of each contact member, respectively, to prevent outward movement of the contact members, a cover for said one side of the base to prevent lateral movement of said contact members from their respective contact recesses when said cover is secured to the base, said cover having a cavity overlying portions of said contacts for receiving a movable bridging contact, and said cover also having an aperture aligned with said central base recess.

14. A switch, comprising, a base of insulating material, contacts mounted on one side of said base at angularly spaced points about a recess in said one side, a cover for said one side of said base having a cavity overlying said contacts and having an aperture aligned with said recess for receiving an operating handle, a longitudinally bowed bridging contact of a resilient conducting material located in said cavity for bridging an opposed pair of said contacts, an operating handle movably mounted in said aperture and having an inner ilange portion adapted to engage an abutment on said cover about said aperture to limit outward movement of said handle, and means mounting said bridging contact on the inner end of said handle for movement therewith and with the convex side of said bridging contact positioned adjacent said handle.

STANLEY L. FRANK.

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

UNITED STATES PATENTS Number Name Date 1,122,931 Horton Dec. 29, 1914 1,179,108 Kaisling Apr. 11, 1916 1,310,110 Wolisohn July 15, 1919 1,674,868 Lee June 26, 1928 1,992,923 Pinkus Feb. 26, 1935 2,419,072 Hall Apr. 15, 1947

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