US2431197A - Rotary type snap action electric switch - Google Patents

Description

Nov. 18, 1947. E. v. PLATT ET AL ROTARY TYPE SNAP ACTION ELECTRIC SWITCH Filed Dec. 10, 1945 Edward M Fig it Zl ilz'am I j 56%610.

Patented Nov. 18, 1947 ROTARY TYPE SNAP ACTION ELECTRIC SWITCH Edward V. Platt, Chicago, Ill., and William J. Aitken, Manitowoc, Wis.

Application December 10, 1945, Serial No. 533,969

13 Claims.

The present invention relates to new and useful improvements in rotary type snap action electric switches and has among its objects to provide a novel and extremely simple, reliable and efiicient snap action electric switch operable by a rotatable actuator both to open and close one or more circuits with snap action, and capable of being used in many different fields.

An important object of the invention resides in the provision of a snap action electric switch wherein kinetic energy imparted to a resilient contact-carrying member, flexed under restrained movement by a rotatable actuator, is released as potential energy to cause the contact-carrying member to suddenly recoil and snap into closed circuit position upon its momentary release from the rotatable actuator and whereupon the contact-carrying member is thereafter restrained in such closed circuit position by the actuator until it is thereafter finally released by the actuator to be quickly moved by its potential energy with snap action into open circuit position.

Another object to the invention is to produce a snap action switch, as aforesaid, so constructed as to afford equally satisfactory operation in very small sizes for handling light current capacities and in large sizes for comparatively heavy current capacities.

Still another object of the invention is to produce a simple and novel snap action switch;

wherein the tendency to arcing is reduced to the minimum and which switch automatically keeps its contact faces clean through relative sliding or wiping movements between them while in engagement with each other during the opening or closing of a circuit therethrough.

A further object of the invention is found in the provision of a simple and novel switch which, by the addition of another contact, is changed from a single throw switch that both opens and closes with a snap action to a double throw switch in which the same snap action characteristics are retained.

The various features of novelty whereby the present invention is characterized will hereinafter be pointed out with particularity in the appended claims; but, for a full understanding of the invention and of its objects and advantages, reference may be had to the following description taken in connection with the accompanying drawing, wherein:

Fig. 1 is a plan view of a single throw switch embodying the present invention, the cover being removed to show the switch parts with the switch in open circuit position; Fig. 2 is a side elevation of the switch, in the direction of the arrows, from line 2-2 of Fig. 1; Fig. 3 is a fragmentary view showing the parts with the switch actuator in the position that it and the parts assume just prior to the circuit closing of the switch; Fig. 4 is a view similar to Fig. 3, showing the switch parts in circuit closed position after the actuator has travelled beyond the position occupied in Fig. 3; Fig. 5 is a view similar to Fig. 4, showing the switch closed and the actuator after it has been reversed in its movement and travelled from the position in Fig. 4 part way back toward the open position of Fig. 1; Fig. 6 is a fragmentary view of the switch as it appears in Fig. 1, but modified to transform it into a double throw switch; and Fig. '7 is a fragmentary View of a modified recess in the actuator disc employed with a modified ,rojection on the resilient member actuated by the disc.

In the drawings the invention is illustrated as a simple hand-operated switch and, for the sake of brevity, the detailed description will be confined to this particular embodiment, although the switch may be embodied in many different forms and be operated in any manner suited to the use to which the switch may be put. The actuator of the switch may be caused to be mechanically or electrically driven with continuous or interrupted rotation. The actuator may make complete rotations or may make partial reverse rotations.

The essential parts of the improved switch include two contacts, one mounted on a snap action blade, and an actuator, together with a suitable supporting base, and a cover shown by broken lines in Fig. 2. One contact, namely the contact it may be stationary, although it is preferably supported by a resilient element II to enable it to yield under pressure. In the arrangement shown, this contact I!) is mounted on one end of a curved spring arm or blade I l which is anchored at its other end to a bracket 12 mounted on the supporting base M. The movable contact I5 is carried on the free end of a preferably comparatively longer resilient member or blade IS an.- chored at its other end to a bracket H also mounted on the supporting base [4. The resilient blade member 16 is preferably arcuate so as to comprise, in general, an arc of a circle of preferably more than one hundred and eighty degrees. The arm H and the resilient blade member I5 are positioned with their concave sides facing each other, with the free end of blade member 16 lying slightly inwardly from and in overlapping, spaced relation to the free end of arm ll.

Within the space enclosed by the arm II and the resilient member I6 is an actuator that functions in the manner of a cam to cause contact I5 to move into and out of eng With 0011- tact IE3. This actuator may conveniently be in the form of a disc I8 of electrically nonconductive material fixed to a shaft I9 projecting at right angles thereto from the base I4 and rotatable in the latter. The shaft I9 may be turned angularly in either direction and through any angle or any number of complete revolutions, if desired, by any suitable means; a finger piece 20 on'the outer end of the shaft being the particular means shown. In the periphery of the disc I8 is a V- shaped recess or notch 2| having'a side 22 that is approximately radial and a second side 24 that is longer than the side 22 and lies almost at right angles to the radial side. The bowed resilient member I6 is deformed transversely, near contact I5, to provide a V-shaped projection 25 near the contact-carrying end of the member I6 which is "somewhat deeper than the recess 2|. The projection-25'is s shaped and the curvature of member IB is such that 'in one angular position of the actuator, the resilient blade projection 25 seats into the recess 2I, as shown in Fig. 1, with the extreme end portion of member I6, carrying contact I5, resting on the peripheral curved or cam surface of thedisc I8. The projection 25 is conveniently formed by bending the member I6 to produce a V having a short leg 25 and a long leg 21.

When the actuator is brought into position illustrated inFig..1, the projection 25 on member I6 '-is seated firmly in the 'recess2I and a large portion of said member lies close to or in actual contact with the curved periphery of the actuator disc I8; contact I lying at a spaced distance from the stationary contact Iii. Upon turning the actuator in the direction indicated by the arrow inFig. 1, namely clockwise, the radial face which forms side '22 of the recess ZI bears against -leg'26 of the projection 25, thus driving-the projection aheadof it and this'l'esults in a partial straightening of the arcuate spring member I6, between its projection 25 and its anchoring point, -and an increased stressing thereof. During the further rotation of the actuator the main portion of the spring blade member proceeds under apiplie'd force to further straighten until the projection 25 thereon is forced outwardly along the side 22 of the recess 2! and eventually suddenly released from the recess '2 I. The relative positions of the parts shown :in Fig. '3 are shown as they .appear just prior to the'sudden release of the pro- ?jecti'on 25 from the recess -2 I, the contact 15 having been moved outwardly by the actuator past the relatively stationary contact IE1.

Aifurther slight angular movement of the actuator, to take it beyond the position in Fig. 3, :results in suddenly releasing the projection 25 from the recess 2| whereby the potential energy in the resilientcblade member I6 is made available -to sharply recoil and snap the blade member 53 back intoa more sharply curved position whereat the projection 25 engages and rides on the curved :peripheral cam face on the disc I? to thereby 1331186 :contact FI'5 to be brought into engagement withithe contact Ill and forciblypre'ssed against thesame, as shown inFig. 4. ,to thereby close the circuit between the contacts I6 and I5.

Became :the free end of member It tries to :pass .through the space between the curved edge of the actuator and the stationary contact, at least .as far as to the angular position that it :arrow'in Fig. '5.

This manual reverse movement results in pushing the movable contact iii a little farther into the space between the actuator and the relatively stationary Contact IE3 and in a further sliding movement of the movable contact it over the contact l8, as can be seen by comparing the relative positions of the contacts in Figs. 4 and 5.

When the actuator has been turned back far enough to bringthe recess 2 I .in the actuator into :alignment with the projection 25, as in the positionshown'in Fig.1, the'projection 25 snaps down into the recessfEI and the circuit is opened.

-While theswitch may be manually shifted from opencircuit to closed circuit and back again to open circuit positions by rocking the actuator back and forth, the actuator may, if so desired,

be continuously rotated in one direction through a complete revolution '01 through any desired "number of revolutions; and the turning of the actuator may be accomplished by intermittently -or continuously-operating mechanical or electrical means, depending on the use to which the switch iisiput.

An important characteristic of this new switch is .thatwhile it can be made with very thin blades and small contacts for handling small amounts 'of currents to permit its manufacture in small compact sizes, it .can also be used with equal success in larger sizes forh'andling currents up to at least fiftyampercs at two hundred and twenty volts.

The switch-is quiet in operation and, therefore,

is well suited for use in situations where this -.characteristic is desirable.

For example, it is much morequiet in operation than the push button type of switch usually employed as a wall switch in homes, for controlling the lighting and other circuits, and can therefore be used to advantage instead of the push button switch.

The double snap action possesses an additional advantage in that a snap action double throw switch may becreated by simply adding a second stationary contact to be engaged by the movab e contact when the projection 25 on the movable contact blade 1!: drops into the recess '2I in the actuator; such engagement being broken when the movable contact blade Iii snaps into engagement with the other illustrated contact as in Fig. 4. Thus, in Fig. 6 there is shown a switch which is substantially like that in Figs. 1 and 2, except that the V-shaped projection 25* is a little deeper than projection 25, to permit the free end of "the resilient blade '28, with its" contact to enter between the free end of the movable blade I6 and the actuator. Contact 29 is preferably made longenough to keep contact {5 from slidingoif the same as the actuator turns from the position sh'ownin Fig. Z6'to one corresponding to that shown in Fig. 3; the opening of the circuit through this bladeZS resulting through the snap 'action'ofcontact 5 into engagement with contact Ill as heretofore explained. It will be seen that there is also a very effective wiping action between contacts 29 and I5, in this instance, particularly while the actuator is moving from the position shown in Fig. 6 to that shown in Fig. 3;

so that the faces of these contacts are kept in good working condition.

Under certain operative and heavy current conditions, it may be desirable to retain the circuit completing contacts I and I under additional pressure and for these purposes the contact arm H may be provided with an auxiliary flexible pressure-exerting element such as the leaf spring 23 one end of which is fixed to the base-supported post 30 and the free end of which exerts pressure against the arm II when the cam face of the disc I8 is in engagement with the deformation 25 with contacts I0 and I5 in face engagement with each other.

The switch is preferably provided with a cover 3|, shown in broken line in Fig. 2, which is removably secured to the electrically insulated base I2 as by a plurality of screws 32.

The angular relationship between the faces 22 and 24 of the recess 2| and the portions 26 and 21 of the V-shaped projection 25 may be modified to vary the snap action, as for example, in an actuator adapted for uni-direction complete rotation and to secure rapid and sharp snap action between the contacts I0 and I 5 for both circuit closing and opening operations, the disc recess and the projection on the blade member It may be modified as shown in Fig. '7 wherein the recess 2| is formed on a reduced angle to provide a sharp V-shaped notch and the cooperating projection l5 is correspondingly Vshaped. These modified constructions cause the blade member IE to move into circuit closed and open positions with very rapid snap actions which are particularly desirable for high capacity switches.

The comparatively wide V-shaped recess 2| and correspondingly shaped projection 25 shown in Figs. 1 to 6 inclusive permit the switch actuator to be completely rotated in not only one direction for closing and opening the circuit but also permit the actuator to be only partially rotated into closed circuit position and then reversedly rotated into open circuit position.

The actuator disc I8 could be provided with a plurality of recesses 2I for providing multiple snap action circuit closing and opening operations during one complete rotation of the actuator disc It is obvious that in a switch of the type herein contemplated and because the drawing discloses the various parts in certain preferred relative positions for illustrative purposes, the use of the word "normally in the description and claims, as it relates to the condition of the switch parts or circuit, is equally as well applicable to defining a circuit which is open or closed, that is, the switch as illustrated may be said to be normally in open circuit position or normally in closed circuit position.

While we have illustrated and described with particularity only a single embodiment of our invention, together with a simple modification, we do not desire to be limited to the precise details thus illustrated and described; but intend to cover all forms and arrangements that come within the definitions of our invention constituting the appended claims.

We claim:

1. A snap action switch for an electric circuit which includes a pair of cooperating, relatively movable contacts, rotatable means, one of said contacts being carried by a resilient member, said member and said rotatable means having interengaging elements to cause said member to be flexed under restrained movement by the rotatable means in one direction for imparting kinetic energy to said member, said interengaging elements being shaped to automatically release said flexed member when said rotatable means has moved to a predetermined position whereat said released member recoils with snap action by potential energy to thereby cause the contact carried thereon to be brought into engagement with the other one of said contacts to close the circuit, said rotatable means having a cam surface in position to engage with and to retain said member in closed cir-, cuit position until such means is turned back again and said elements again snap into engagement with each other and said contacts separate by a snap action.

2. A snap action switch as set forth in claim 1. said rotatable means including a rotatable element having an instrumentality which is adapted to engage a part of said member to thereby flex said member during its restrained movement.

3. A snap action switch as set forth in claim 1, said rotatable means including a rotatable disc having a recess in its periphery and said resilient member having a deformed portion normally in open circuit position resting in said recess, said deformed portion of said member being engaged by a face of said recess when said disc is rotated thereby flexing said member under its restrained movement by said rotatable means.

4. A snap action switch for a pair of circuits, a first contact in one of said circuits, a second contact in the other of said circuits, a rotatable element having a recess in its periphery, a resilient member comprising an arcuate blade fixed at one end, carrying a third contact at its free end, and having projection extending inwardly from its concave side, said resilient blade member being normally positioned so that said projection rests in said recess and said third contact thereon is in engagement with said second contact closing the circuit therethrough, the parts being so constructed and proportioned that upon the movement of said rotatable element in one direction and through the operative engagement of said projection with said recess and the forcible carrying of the projection along with the rotatable element, said resilient blade member is caused to be stressed and flexed outwardly until said resilient blade member is suddenly released from its operative engagement by said rotatable element and moves with snap action by potential energy inwardly whereupon said resilient blade member is re-engaged by said rotatable element to cause said resilient blade member to bring its said third contact into engagement with said first contact to close the circuit therethrough and to open the circuit through said second contact.

5. In a switch, a circuit including stationary contact, a spring member having one end in normal open circuit position spaced from said contact and its other end anchored, a movable actuator adjacent to said member and having thereon a cam face and a recess extending inwardly of the cam face, said member having near its free end a cam-engaging projection that at all times engages the actuator, the parts being so arranged that said member is either in open or closed circuit position depending on whether the projection is seated in the recess or is in engagement with the cam face and the recess and the projection being so shaped that when the actuator is moved into a predetermined position the projection snaps into the recess and releasably interlocks the actuator'and said memberywhereupon a reverse movement of the actuator causes the projection to be carried along with the same and said member to be stressed and distorted tosuch an extent that the projection is lifted out of the recess by said member and said member recoils sharply, with the projection riding on the cam face, into circuitclosing position.

6. A switch as set forth in claim having, in addition, a second stationary contactso located that the free end of the spring member engages therewith when the projection snaps into the recess, in the actuator and disengages therefrom when the projection snaps out of the recess,

7. In a switch for an electric circuit having an arm-supported contact, a bowed spring member carrying a contact at its free end spaced from said. arm-supported contact in open circuit position and anchored at its other end, a rotatable actuator partially embraced by said member and having thereon a cam surface, the actuator having a recess extending below the cam surface, said member having near the free end a cam-engaging projection normally seated in said recess when said member and the actuator are in their open circuit positions, the relative positions of said member and the actuator being such that when the actuator is rotated in the circuit closing direction it carries the projection along with it toward the anchored end of said member, whereby said member is caused to be stressed and straightened to such an extent that said projection is moved out of said recess and said member recoils sharply into a position wherein said projection rides on the cam surface whereupon said membercarried contact is snapped into engagement with said arm-supported contact to close the circuit.

8. A switch as set forth in claim 7, wherein said arm-supported contact comprises a resilient arm anchored at one end and carrying the contact at the free end, said resilient arm yieldingly resisting the pressure imparted to said bowed-springsupported contact 'by the engagement of said projection with said cam surface of the actuator.

9. A switch as set forth in claim 7, wherein the face of the contact carried by said spring member is approximately parallel to the direction of travel of said arm-supported contact at the time the former is moving into engagement with the armsupported contact, so that a wiping action occurs "between said contacts during the movements of said bowed spring member into closed and open circuit positions.

10. In an electric snap action switch, an insulating supporting base,'a resilient arm having one end fixed to said base and carrying a contact at its free end, a resilient member having one end fixed to said base and carrying a contact at its free end positioned near but offset relatively to the contact carried at the free end of said resilient arm and said resilient member being provided with a projection, an actuator rotatably mounted on said supporting base and including a circular disc having at least one recess in its periphery in which said projection rests during open circuit position of the actuator, said actuator disc recess having engagement with said projection during partial rotation of the actuator whereby during said partial rotation the projection is carried along with the actuator so as to exert a thrust lengthwise of said resilient member, whereby the latter is flexed under restrained engagement by a face of said recess on the projection until said actuator has been rotated to a point whereat said projection is lifted out of and is automatically released from said recess and ermits said resilient member to recoil and reverse its movement to cause said projection to come into engagement with the peripheryof said disc and simultaneously cause the resilient-member-carried contact to be brought into engagement with said resilientarm-carried contact.

11. In a snap switch, a rotatable disc having a V-shaped recess in its periphery, a resilient arcuate blade, fixed at one end, located in the plane of the disc and having near the free end a deformation of V-shape, said blade being under initial stress to cause said deformation to bear on the periphery of the disc and to drop into the recess when they register with each other, a contact on the free end of the blade, and a stationary contact in position to engage with that on the blade when the latter is at rest with the deformation bearing on the periphery of the disc and to become disengaged when the deformation drops into the recess; the recess and the deformation being so shaped that when the disc is turned in one direction, while the deformation is in the recess, the deformation is carried along with the disc until the latter reaches a predetermined position whereat the deformation rises out of the recess and rides on the periphery of the disc as the blade recoils, thereby to bring the contacts into engagement with each other,

12. A snap action switch as set forth in claim 11, wherein there is included a spring arm on which the stationary contact is mounted.

13. A snap action switch as set forth in claim 11, including a spring arm on which the stationary contact is mounted, so as to be yieldablfi, and auxiliary resilient means that exerts additional pressure on the stationary contact.

EDWARD V. PLATT. WILLIAM J. AITKEN.

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

Ul-IITED Number Name Date 1,213,799 Perrin Jan. 23, 1917 2,059,712 Schellenger Nov. 3, 1936 2,122,643 Golemb July 5, 1938

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