US2822438A

US2822438A - Snap action switch

Info

Publication number: US2822438A
Application number: US474343A
Authority: US
Inventors: Tyzack Harold
Original assignee: CARTER PARTS CO
Current assignee: CARTER PARTS CO
Priority date: 1954-12-10
Filing date: 1954-12-10
Publication date: 1958-02-04
Anticipated expiration: 1975-02-04

Description

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SNAP ACTION SWITCH Filed Dec. l0, 1954 2 Sheets-Sheet 2 :EnEr- .60a ma.

30a. E E fr.- L --J Il I 4. .lll/1111111111111 SNAP Ac'rIoN SWITCH Harold T yzack, Schiller Park, Ill., a'ssignor to Carter Parts Company, Chicago, Ill., a corporation of Illinois Application December 10, 1954, Serial No. 474,343

4 Claims. (Cl. 208-67) The present invention relates to a snap action switch, and more particularly to an improved element for effecting movement of a movable contact by a snap action into and from engagement with a fixed contact.

It is an object of the present invention to provide a snap switch which is constructed and arranged so that the contacts are opened or closed with a snap action 'irrespective of the rate of movement of the force which is applied to the actuating mechanism of the switch.

It is another object of the present invention to provide a snap switch of the foregoing character in which the movable parts of the snap switch comprise three parts, two of which are spring elements, such parts being constructed and arranged so that the opposing forces of the spring elements cancel each other in such a manner that a state of static equilibrium is attained, thereby enabling the three component parts to be assembled in a subassembly and handled in production as such.

It is another object of the present invention to provide a snap switch of the foregoing character in which a novel arrangement of parts is provided so that a minimum of i uniform operating characteristics can be obtained from standard parts without requiring adjustment of the aforesaid sub-assembly or the complete assembly, thereby aiding in reducing production costs to a minimum.

It is still another object of the present invention to provide a snap switch of the foregoing character in which the spring elements in the sub-assembly can be used with equal facility in either a double throw snap switch or a normally closed or normally open type of snap switch.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

In the drawings:

Fig. 1 is a plan view of a normallly open or closed snap switch embodying the present invention;

Fig. 2 is a section taken on the line 2-2 of Fig. 1;

Fig. 3 is a section taken on the line 3 3 of Fig. 2;

Fig. 4 is an end elevation of the embodiment shown in Figs. 1 to 3;

Fig. 5 is a section similar to Fig. 2 of a double throw snap action switch embodying the present invention;

Fig. 6 is a section taken on the line 6-6 of Fig. 5; and

Fig. 7 is an end elevation of the embodiment shown in Figs. 5 and 6.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also,

United States Patentice tion of the present invention will be given. The embodiment shown in Figures l to 4 includes a housing 10 of insulating material having a front section 12 and a rear section 14 which are secured together by a pair of rivets 16. Pins 18 are an integral part of the section 14 and fit into mating holes in section 12 to aid in assembling the casing sections. Holes 20 may also be provided for use in mounting the switch unit.

The housing 10 has a cavity 22 within which is carried a sub-assembly of three parts, the contact carrier 24, the actuator 26 and the U-shaped rocker spring 28. Riveted to the stationary end of the contact carrier 24 is a terminal 30. These parts can be joined together as va sub-assembly, if desired, and can be inserted directly into the housing 10 as a single unit.

The contact carrier 24 is mounted in the housing 10 in cantilever fashion so that the end to which terminal 30 is attached will be rigidly held, and the opposite end will be free to move between the stationary contacts32 and 34. The latter are directly connected with the

terminals

36 and 38. The movable end of contact carrier 24 has the contacts 40 and 42 securely mounted thereon, and they are adapted to engage the stationary contacts 32 and 34.

The contact carrier 24 is formed by a stamping operation from any suitable conducting metal and has a U- shaped cut-out 44 by which a spring arm 46 is formed Within the contactor arm 48. The free end of spring arm 46 has a V-shaped notch cut therein and the notch comes to a knife edge as can be seen in Figure 2. The V-shaped notch straddles the actuator 26 in the circular groove 50 which circumscribes the actuator, the knife edge of spring arm 46 being the only portion of the latter to be in engagement with the actuator 26.

The U-shaped rocker spring 28 has a V-shaped notc cut in one of its ends, and this notch also comes to a knife edge. This notch straddles the actuator 26 in the circular groove 50 but in a position diametrically opposite the spring arm 46, and, as in the case of spring arm 46, only the knife edge engages the actuator 26. The opposite end of the U-shaped rocker spring 28 'has a slot 52 which receives a tongue S4 extending from the contactor arm 48. The edge 56 of contactor arm 48 comes to a knife edge so that when the rocker spring 28 tilts or pivots, in a manner to be described, the bearing surface between the rocker spring 28 and the contactor arm 48 is limited primarily to the knife edge 56. lThus, it can be seen that substantially the only points of engagement between the three movable parts, the contact carrier 24, the actuator 26 and the rocker spring 28 are knife edges and those` in the groove 50 are essentially point contacts so that the tilting or pivoting action that occurs between these parts is practically frictionless.

in the normal operation of this embodiment of the invention, the coil spring 58 will urge the actuator 26 to its uppermost position in the housing 10 with the push button end portion of the former projecting through the opening 6). The movable contact 42 Will be in engagement with contact 34 so that the

terminals

30 and 38 may be connected in either a normally open or normally closed circuit, as desired.

The contact 42 can be moved away from stationary contact 34 and contact 48 moved into contact with stationary contact 32 by a snap action merely by pressing down on the button end of actuator 26. With the switch in the position shown in Figure 2 the rocker spring 28 is in a state of compression so that the ends are exerting `anequal but opposite thrust against the actuator 26 and the contacter arm 48. Since the ends of the rocker spring 28 are in a plane that is inclined to the plane of the contacter arm 48, the spring 28 will exert a compejiient of pressure tending to hold the contact 42 against stationary contact 34. However, whenilthe plane eentaining uend s of` the rocker spring 28`pass'es into arid thereafter tilts beyond the plane Aof'contacterar'ni 4 8,

tion shown in Figure 2 arid as the ends Vof 'the rocker spring 28 pass through the plane` of the oontact'or 48 the forces exerted by` -the rocker' spring 28 will he such as Vto cause the sub-assembly 'to return to the position shown in Figure`2. In order to aid in maintaining unifoi opration of the svv'itcli and to assure that the Snap Vctiil Will Ccl'ir t S''bst'tilly flic Same posinon of 'navi-.nient of die 'actuator 26, the edges or the contacter rf 48 are folded over as at 60, thereby preventing bowing of the contactenY a'r'rn' '48 and assuring thatfit 'will remain in suosta'ntially 'one' 'plane' during opti f the Switch.

Front the foregoing it can be seen that the movements of the component parts' are substantially frictionles's and the parts' are supported so that there can be ne misalignment or' shifting which may cause irregular operation. Since thepa'rt's will encounter substantially no wear nor' is there" any likelihood of damage, a very long life is assured.

The present invention is not limited in use to a precise switch of the type described above. Other applications of the invention can be made, and one such application is' illustrated in Figures 5 to 7. This modification is the same as the one previously described, but it is a double throw switch which has an actuator 26a which projects' through the openings 4`6021 in both the' top and bottom of the housing a. Thus, the contacts 40 and 42 will remain in engagement with whichever of

stationary contacts

32a or 34a as may be selected, merely 'by' pressing the actuator y26a to its upper position shown,

or Ato' a corresponding lower position which will cause Contact 40ct to be in engagement `with stationary contact 32a. In other respects this modification isl the same as the one illustrated in Figures 1 tol 4' and reference is made to the description of that niediiication for anyy of the other parts ct the present modification.

Having thus described my invention, I claim:

1. In a snap action switch, a contacterv element comprising a spring blade'having a U-shaped cut-out s'o as to form a hat spring arm within a contacter arm,` the Vfree end of said spring armhaving a V-shaped knife edge,

a rocker spring pivotally connected to said contacter arm and having an end with a V-'shaped knife edge disposed opposite to the corresponding edge' of the spring arm, and an actuatorv extending axially through the cut-out' of the spring blade', said actuator having a circumferential groove for receiving said knife edges so that each of the latter straddles said actuator making peint contacts therewith and the spring arm and rocker spring are movable on axial movement of said actuator, said actuator also having a spring for urging the spring arm and rocker spring in one direction and a push button for manually moving these elements in the opposite direction.

2. In a snap action switch, a contacter element cornprising a spring blade having a U-shaped cut-out so as to term a hat spring arm within a contacter arm, the free end of said spring arm having a V-'shaped knife edge, a rocker spring pivotally connected to said contacter arm and having an end with a V-'shaped knife edge disposed opposite to the corresponding edge of the spring arm, and an actuator extending axially through the cut-out of the spring blade, said actuator having a circumferential groove for receiving said knife edges so that each of the latter straddles said actuator making point contacts therewith and vthe spring arrn and rocker-spring are inevahle on laxial movement of said actuator, lsaid actuator also having push buttons on its opposite ends for selectively movig the spring arm iii opposite directions.

3. Ina 'snap action sivith, the combination comprising a fixed Contact, a 'contacter element including a spring blade with a U-shap'ed cut-'out so as to forth a spring ari within a contacter arr'n, the free Yend of said spring arr'n having a V-shp'ed knife edge, a rocher spring pivotally connected to' 'saidvconta'citor arni and having an end with a tl-shaped knife edge disposed opposite to the corresponding edge of thc spring arm, and an actuator red extending axially through the cut-out of the 'spi-ing blade, said actuator rod having a circumferential groove for receiving said knife edges so that each of the latter straddles said actuator rod making point contacts therewith, said spring blade carrying a `contact movable inte contact with said xed Contact so that movement of said actuator rod will effect rhovcr'nent of the movable contactby a snap action into and 'from engagement with the fixed Contact.

4. In a snap action switch, the combination defined in claim 3'wher'ein the lateral edges of said contacter arm opposite the c ut out of the blade are bent over te prevent bowing of this portion of the contacter arm.

References Cited in the file of this patent UNirED STATES PATENTS 2,429,812 Hausler Oct. 28, 1947 2,459,661 MacFarla-nd Jan. 18, 1949 2,538,512 Gates et al.- Jan. 16, 1951 2,556,216 Raney -e June l2, 1951 2,594,216 Reeser a Apr. 22,I 1952 2,598,856 Swan et al. -e `June 3, 1952 2,599,473` Miller Y -2 2 June 3, 1952 2,626,999 Johnson f -a lan. 27', 1953 2,629,791 Tourneau l v Feb. 24,- 1953 2,644,052 Martin n- June 30, 1,953 2,748,214 Irnrnel May 29, 1956