US3175065A

US3175065A - Push button operated snap-acting electric switch

Info

Publication number: US3175065A
Application number: US252246A
Authority: US
Inventors: Walter F Strader
Original assignee: PUNTON CORP
Current assignee: PUNTON CORP
Priority date: 1963-01-17
Filing date: 1963-01-17
Publication date: 1965-03-23
Anticipated expiration: 1982-03-23

Description

March 23, 1965 w. F. STRADER 3,175,065

PUSH BUTTON OPERATED SNAP-ACTING ELECTRIC swITcH 2 Sheets-Sheet 1 Filed Jan. 17, 1963 e 2% w on 5 mm M W5 a N. w 1 fi,% m W B 97 4 4. .T 1 h l h a a J 4 i March 23, 1965 w. F. STRADER 3,175,065

PUSH BUTTON OPERATED SNAP-ACTING ELECTRIC SWITCH Filed Jan. 17, 1965 2 Sheets-Sheet 2 United States Patent 3,175,065 PUSH BUTTON OPERATED SNAP-ACTING ELECTRIC SWITCH Walter F. Strader, Canoga Park, Calif., assignor to Punton Corporation, Culver Qity, Calif., a corporation of California Filed Jan. 17, 1963, Ser. No. 252,246 15 Ciairns. (til. 200159) The present invention relates to electric switches for controlling electric circuits, and more particularly to plunger operated switches for engaging and disengaglng electric contacts.

In the control of electrical circuits, it is desirable to provide electric switches which are compact and reliable and which preferably operate with a quick or snap action to engage and disengage cooperating contacts to complete and break the electric circuits therethrough. It is desirable in many instances that such switches be operated by the rectilinear movement of a plunger which may be manually operated, as by a push-button, or operated by other means, as in the case of limit switches and remotely operated switches.

Particularly in the case of push-button operation, it is desired that illumination be provided to more readily identify the service performed by the switch.

In some operations it is desired that the switch be stable in both its operating positions, and that it be operated from one stable position to the other by successive movements of the plunger in the same direction. On the other hand, it is sometimes desired that the switch have but one stable position, and the other position be momentary in the sense that it will remain in the latter position only while the plunger is held in an operated position, with the switch automatically returning to its one stable position when the plunger is released. It is further desirable that the changeover between bistable and momentary operation of the switch be accomplished with a minimum change in the operating parts thereof.

It is an object of the present invention to provide an improved electric switch including engageable and disengageable contacts for controlling electric circuits.

Another object of this invention is the provision of an improved plunger operated electric switch of compact size and providing for snap operation of the switching con tacts.

Another object of this invention is the provision of an improved, compact, snap acting, push-button electric switch having an illuminated push-button for ready identification of the switching service.

A further object of this invention is the provision of a plunger operated electric switch having bistable movable contact positions and operated from one stable position to the other by successive operations of the plunger in the same direction.

A still further object of this invention is the provision of an improved plunger operated, snap acting, electric switch readily modified from bistable to momentary operation by change of a minimal number of parts.

These and other objects and features of this invention will be readily apparent to those skilled in the art from the following specifications and the appended drawings, in which:

FIGURE 1 is a longitudinal sectional view through a push-button electric switch according to the present invention;

FIGURE 2 is a view similar to FIGURE 1, but With the push-button and plunger moved to their fully operated position;

FIGURE 3 is a transverse sectional view on the line 3-3 of FIGURE 1;

FIGURE 4 is an enlarged partial sectional view on the line 44 of FIGURE 3;

FIGURE 5 is a longitudinal sectional view taken at right angles to the view of FIGURE 1;

FIGURE 6 is an enlarged detail view Within the circle 6 of FIGURE 5;

FIGURE 7 is an expanded perspective view of the snap acting operating mechanism of the switch;

FIGURE 8 is a partial view showing the stable position of the switch when modified for momentary operation; and

FIGURE 9 shows the momentary or non-stable position of the switch of FIGURE 8.

Referring first to the embodiment of the invention selected for specific illustration in FIGURES 1 through 7 of the drawings, there is provided an outer cylindrical casing 11 having a forward facing shoulder 12 and a reduced threaded portion 13 forwardly thereof. A cap nut 14 threads on the portion 13 to clamp the switch in position on a panel wall 15, with the threaded portion 13 extending through a complementary opening in the wall. The casing 11 may be of metal, for example, anodized aluminum, or, alternatively, may be of molded plastic or other insulating material.

Within the forward portion 13 of the casing 11 is disposed an insulating liner 16, and rearwardly of the liner 16 the casing 11 encloses a pair of

insulating housings

17 and 18. The housing 18 is cup-shaped and extends to the rear end of the casing 11 where its back opening is closed by a disc or plate 19, also of insulating material. The hollow interior of the cup-shaped housing 18 provides a contact chamber 21 within which is disposed a switching plunger 22 of insulating material, guided for reciprocal movement within an opening 23 through the base of the housing 18, and in a cylindrical recess 24 in the forward face of the closure disc 19.

The periphery of the closure disc 19 is notched at a number of locations thereabout, as at 25, to accommodate and support the stems 26 of relatively stationary electric contact elements whose interior ends extend within the chamber 21 to form contacts 27 and whose exterior ends 28 form terminals to which circuit wires 29 may be soldered or otherwise electrically connected. It will be understood that any desired number of contacts 27 may be provided within the chamber 21, depending upon the physical sizes of the switch and the contact elements. The contact elements are preferably formed of resilient material so that their inherent bias will provide contact pressure at their engaging surfaces. The positions of the contacts 27 will determine whether they will be engaged or disengaged by movable contacts in the bistable positions of the switching plunger 22 and with which copperating movable contacts they will be engaged.

To interconnect the stationary contacts 27, the switching plunger 22 is provided with conducting rings 31 mounted in spaced arrangement on its periphery and contacting and disengaging the stationary contacts 27 in any desired relationship, depending upon the location of the stationary contacts. Thus, the switching circuits which are respectively closed and opened in the bistable positions of the switching plunger 22 may be varied at will by the location and number of the stationary contacts 27.

The switching plunger 22 has a central, rear-opening bore 32 within which is disposed a spring 33 which bears against the end of the bore 32 and against the bottom of the recess 24 to bias the switching plunger 22 into its forward stable position, as shown in FIGURE 2.

The insulating housing 17 is provided with a generally centrally located opening 35 within which is disposed a snap-action operating member, indicated generally at 36, mounted for rotation on a transverse shaft 37. The

operating member 36 includes a cam portion 38 engaging the forward surface of the switching plunger 22. Integral with and at opposite sides of the cam portion 38 are a snapeaction cruciform portion 39 and a ratchet star Wheel portion 41.

Within the insulating liner 16 an operating plunger 45, preferably of conducting metallic material, is slidably mounted for rectilinear movement. The rear portion of the plunger 45 is preferably formed as a hub 46 having a circumferential slot 47 therein communicating with a longitudinal slot 48. A split spring ring 49 is disposed in the circumferential slot 47 and pivotally mounts an operating arm 51 within the slot 48. The arm 51 extends rearwardly through a slot 52 in the housing 17 and terminates in an L-shaped portion 53 whose interior angle receives the fingers 54 on the star wheel portion 41 of the operating member 36.

A spring strip 40 has a fixed end 50 clamped between the sleeve 16 and the housing 17 and its free end bearing against the plunger arm 51 to bias the arm 51 in a clockwise direction, as shown in FIGURES 1 and 2, so that the L-shaped end 53 will always be held against the star wheel portion 41.

The cruciform portion 39 of the operating member 36 is shown in enlarged detail in FIGURE 4 as Comprising four arms 55 defining pockets 56 therebetween. The cruciform portion 39 is disposed between a pair of transverse holes 57 and 53 in the housing 17; and in the

holes

57 and 58 are disposed detent balls 59 biased toward the shaft 37 by springs 61. In the position illustrated in FIGURE 4, the cruciform portion 39 is in its dead-center position with the detent balls 59 engaging the ends of opposite arms 55 and about to snap into the pockets 56 to rotate the operating member 36 with a snap action through substantially 45. The diameter of the housing 17 is reduced at its rear portion 64 to receive an insulating sleeve 65 which serves to hold the springs 61 and detent balls 59 assembled in the housing 17.

As shown in FIGURE 1, the plunger 45 is in its released, outermost position and the switching plunger 22 is in its rearmost position, being held therein by the surface at 62 on the cam 38. As shown in FIGURE 2, the switching plunger 22 is in its extreme forward position, being permitted to move thereto under the bias of spring 33 by the surface at 63 on the cam 38. The surfaces 62 and 63 are duplicated 180 apart on the cam 38 so that there are provided two rear and two forward stable positions for the switching plunger 22 for each 360 rotation of the cam 38. The snap-action cruciform portion 39 is related to the cam 38 so that the cam surfaces 62 and 63 engage the forward surface of the switching plunger 22 when the detent balls 59 are within pockets 56 on the cruciform portion 39.

The housing 17 is provided with a pair of longitudinally extending, peripheral notches 66 and 67 (FIGURES and 7) through which extend conducting

strips

68 and 69. The

strips

68 and 69 extend through slots 71 in the bottom wall of the cup-shaped housing member 18, and through complementary slots 72 in the insulating disc 19 to provide exterior end terminals 73 and 74 for the connection of external wires 75 supplying power for push-button illumination.

The hub 46 of the plunger 45 is provided with a central recess 76 in which is disposed one end of a compression spring 77, the opposite end of the spring 77 being received within a circular recess 78 in housing 17. The conducting strip 69 is bent over the forward face of the housing 17, as shown in FIGURE 6, and into the recess 78 where it is soldered or otherwise electrically connected to the spring 77. Electrical connection is thereby made from terminal 74 through conducting strip 69 and spring 77 to plunger 45.

The end of conducting strip 68 is bent over the forward face of the housing 17 to be received within a forward slot 81 therein. A thin insulating sheet 82 is disposed 4 between the conducting strip 68 and the spring 77, and the end of the conducting strip 68 is attached to a bulb contact spring 83. Upon the forward end of the spring 83 is mounted a cap 85 extending through an insulating sleeve 86 which serves to insulate the cap 85 from the plunger 45 and the spring 77 The plunger 45 has a forward central recess or bore 87 within which is mounted a bulb socket 88, as by means of a snap ring 89. The bulb socket 88 is thereby electrically connected to the plunger 45 and the terminal 74, and the socket in turn connects to the conventional cylindrical terminal of the bulb 91. The bulb 91 has a conventional rear terminal 92 which is engaged by the cap 85 to complete the circuit to the bulb through the bulb contact spring 83 and conducting strip 68 to terminal 73.

In the specific embodiment of the invention illustrated, the plunger 45 is operated by a manual push-button 93 which may take any particular form, being here shown as a box-like housing 94 closed by a rear plate 95 in which is inset a metallic sleeve 96. The sleeve 96 is secured to the plunger 45 to mechanically connect the push button to the plunger. The bulb 91 extends through the sleeve 96, and the interior surface of the plate 95 and sleeve 96 may be curved and silvered, as at 97, to form a reflecting surface to concentrate the light from the bulb 91 to the forward portion of the push-button 93.

It will be understood that the push-button 93 is not an essential part of the switch according to the present invention, nor is the illumination thereof essential to the switch operation. The plunger 45 may be moved rectilinearly in any desired manner, for example by a machine part as a limit switch, by an electromagnet in remote operation, or by any other desired means.

In the push-button embodiment specifically illustrated in FIGURES 1 through 7, plunger 45 is moved rearwardly by manual operation of the push-button 93 from the position of FIGURE 1 toward the position of FIG- URE 2, and the plunger 45 returns to its outermost position of FIGURE 1 under the action of the compression spring 77. FIGURE 2 shows the extreme inward positions of the plunger 45 and push-button 93, but it is unnecessary in switch actuation for the plunger to assume this extreme poistion, since as soon as the snap-action cruciform portion 39 is rotated just past the dead-center position of FIGURE 4, the switching parts will snap to the next stable position independently of further movement of the plunger and push-button.

With the parts in the stable position of FIGURE 1, the switching plunger 22 is held in its rearmost position by engagement of the surface 62 of the cam 38 with the forward surface of the switching plunger. To move the switching plunger 22 into its second stable position, the push-button 93 is engaged to move the plunger 45 inwardly against the outward bias of the spring 77. The plunger arm 51 moves with the plunger 45 and its L- shaped end engages one of the fingers 54 of the star wheel portion 41 to rotate the operating member 36. The plunger arm 51 is held against the finger 54 by the spring strip 40 and the operating member 36 is thereby rotated in a clockwise direction, as viewed in FIGURES 1 and 2.

As the operating member 36 rotates, the detent balls 59 will be moved radially outwardly by the adjacent arms 55 of the snap-action cruciform portion 39 until the deadcenter position of FIGURE 4 is reached. During this. rotation of substantially 45 of the operating member 36, the switching plunger 22 remains substantially stationary, being held in its rearmost position by the surface of the cam 38 adjacent the surface 62. As the arms 55 pass just beyond the dead-center position of FIGURE 4, the detent balls 59 snap into the next pockets 56 on the cruciform member 39 and thereby quickly rotate the operating member 36 through the next 45 with a snap action so that the surface 63 on the cam 38 is rapidly presented to the end of the switching member 22, which itself,

moves forwardly with rapidity or a snap action under the bias of compression spring 33. The parts are then in the position shown in FIGURE 2, which is the second stable position for the switching plunger 22.

Release of the push-button 93 is followed by outward movement of the plunger 45 under the bias of compres sion spring 77, and the plunger again assumes the position of FIGURE 1. In this outward movement of the plunger 45 the operating member 36 remains stationary and the plunger arm 51 slides outwardly and over the next succeeding finger 54, rotating a small distance counterclockwise in this movement against the bias of the spring strip 40. The L-shaped end 53 of the plunger arm 51 is thereby positioned to engage the next succeeding finger of the star wheel portion 41, but with the switching plunger 22 in its forwardmost position, as of FIG- URE 2. The switch of FIGURES 1 through 7 is thereby seen to have bistable operation in that the switching plunger 22 has two stable positions, rearwardly, as in FIGURE 1, and forwardly, as in FIGURE 2.

With the switching plunger 22 in the position of FIG- URE 2 and the plunger 45 and pushbutton 93 in their outward, realeased positions, as in FIGURE 1, a second rearward movement of the push-button and plunger will effect further rotation of the operating member 36, in the same direction, by the engagement of the L-shaped end 53 of the plunger arm 51 with the next succeeding finger 54 on the star wheel portion 41. The first 45 of this rotation again moves the detent balls 59 radially outwardly to the dead-center position where they are aligned with the arms 55 on the snap-action cruciform portion 39. In the first 45 of movement, the switching plunger 22 remains substantially in its forwardmost position, since the curvature of the surface of cam 38 adjacent the surface 63 permits the plunger 22 to remain forwardly under the bias of its spring 33.

When the snap-action cruciform portion 39 is moved slightly over center, the balls 50 snap into the next pair of pockets 56 to rotate the operating member 36 through the next substantially 45 with a snap action to rotate the cam 38 rapidly and present the surface 62 thereof against the end of switching plunger 22. The switching plunger 22 is thereby moved from its forward stable position of FIGURE 2 back into its rear stable position of FIGURE 1. Successive rearward actuations of the pushbutton 93 will thereby effect movement of the switching plunger 22 between its two stable switching positions with a snap action in each case.

In the snap-action rotation of the operating member 36, as the detent balls 59 snap into the next succeeding pair of pockets on portion 39, the member 36 rotates freely with respect to the plunger operating arm 51, since the finger 54 engaged by the L-shaped end 53 is entirely free to leave the end of the arm and rotate by itself out of engagement with the interior socket provided by the L. The movement of the operating member 36 and of the switching plunger 22 therefore occurs with a true snap action in both directions of movement of the switching plunger, regardless of the speed of operation of the operating plunger 45.

The switching operations effected by the switching plunger 22 in moving between its two stable positions will be determined by the location and number of the stationary contacts 27 which are associated with the contact rings 31 on the switching plunger. As illustrated in FIGURE 1, one contact is shown engaging each of the conducting rings; in FIGURE 2 the contacts are shown disengaged. These contacts could obviously be arranged to engage the same conducting ring, or either or both could be arranged to engage alternate conducting rings in the two positions. The optional positioning of the contacts provides for wide variation in the switching operations to be performed with relation to the circuit wiring 29.

It will be seen that as long as the conductors 75 are connected to a suitable source of electrical energy, the

bulb 91 will be illuminated to provide any desirable information at the push-button 93. The illuminating circuit runs from terminal 73, through conducting strip 68, bulb contact spring 83, cap to bulb contact 92, and from the bulb cylindrical contact through the bulb socket 88, plunger 45, plunger operating spring 77, and conducting strip 69 to terminal 74.

A monostable or momentary operation. construction of the electric switch according to the present invention is illustrated in FIGURES 8 and 9. In this embodiment a plunger arm 101 has been substituted for the plunger arm 51 and an operating member 102 has been substituted for the operating member 36. The star wheel portion 41 of the operating member 36 is omitted from the operating member 102 and substituted therefor is a simple pin 103 which rides in a slot 104 in the end of the plunger arm 101 so as to have a lost motion connection therewith. The operating member 102 includes the snap-action cruciform portion 39 and the detent balls 59 cooperating therewith, as described in connection with the form shown in FIGURES 1 through 7. Whereas the operating member 36 rotated continuously in one direction, that is clockwise as viewed in FIGURE 1, the operating member 102 rotates through only in opposite direction to its two extreme positions, shown in FIGURES 8 and 9.

In FIGURE 8 the parts are in their stable position with the plunger 22 held in its rearmost position by the surface 105 on the operating member 102. In this position the plunger 45 is in its outermost position under the bias of its spring 77. When the plunger 45 is moved rearwardly, the lost motion of the pin 103 in the operating member 102 is rotated through 45 until the snap-action cruciform portion 39 assumes the dead-center position of FIGURE 4. As soon as the operating member 102 is moved past this dead-center position, the balls 59 snap into the pockets 56, as before, to rotate the operating member 102 through an additional 45 with a snap action, thus permitting the switching member 22 to move forwardly with a snap action under the bias of its spring 33. This movement of the switching plunger 22 is permitted by the surface 106 on the cam surface of the operating member 102. In this snap rotation of the operating member 102, it will rotate freely, independently of the plunger arm 101, through the lost motion connection provided by the pin 103 and slot 104. Thus the movement of the switching plunger 22 is a true snap action regardless of the speed of movement of the plunger 45. In the initial 45 of rotation of the operating member 102, its cam surface maintains the switching plunger 22 in its rearmost position, and it is only during the snap movement of the operating member 102 that the switching plunger 22 moves forwardly, also with a snap action.

The position of FIGURE 9 is an unstable or momentary position which will be maintained only so long as the plunger 45 is held inwardly. When the plunger 45 is released from the position of FIGURE 9, it will move outwardly under the bias of spring 77 and, after the lost motion between the pin 103 and slot 104 is taken up, the operating member 102 will be rotated in a counterclockwise direction. The first 45 of rotation is depend ent upon the speed of movement of the plunger 45 until the dead-center position of FIGURE 4 is reached and, when this is passed, the operator 102 will move with a snap action, independently of the speed of movement of the plunger 45, to return the switching plunger 22 to its rearmost position, as in FIGURE 8. The initial 45 rotation of the operating member 102 again occurs without substantial movement of the switching plunger 22 due to the shape of the cam face on the operating member, so that the switching movement of the switching plunger 22 occurs with a snap action after the operating member 102 passes its dead center.

It is therefore seen that by changing only the operating member from 36 to 102 and the plunger arm from 51 to "Z 101, the electric switch according to the present invention may be changed from bistable operation to monostable or momentary operation. All other details of the monostable operating switch of FIGURES 8 and 9 may remain the same as those described in the bistable operating switch of FIGURES 1 through 7.

While certain preferred embodiments of the invention have been specifically illustrated and described, it will be understood that the invention is not limited thereto, as many variations will be apparent to those skilled in the art, and the invention is to be given its broadest interpretation within the terms of the following claims.

I claim:

1. An electric switch comprising: cooperating electric contacts; a rectilinearly movable switching member for controlling the engagement and disengagement of said contacts; a movable operating member; a rotary cam for effecting rectilinear movement of said switching member; means for effecting rotation of said cam to move said switching member in response to movement of said operating member to perform a switching operation; and snap-action means in addition to and integrally connected to the cam for effecting rotation of said cam and movement of said switching member thereby in opposite directions with a snap action independently of the speed of movement of said operating member to effect both snap engagement and snap disengagement of said contacts.

2. The electric switch defined in claim 1 in which said operating member is rectilinearly movable and in which biasing means is provided for moving said operating member in one direction.

3. The electric switch defined in claim 1 in which the means for rotating said cam includes ratchet means in addition to the cam and snap-action means interposed between said operating member and the cam for effecting progressive rotation of the cam in the same direction upon successive movements of the operating member.

4. An electric switch comprising: a rectilinearly movable operating member; means biasing said member for movement in one direction; cooperating electric contacts; a rectilinearly movable switching member for controlling the engagement and disengagement of said contacts; a rotary cam for effecting movement of said switching member in one direction; biasing means for moving said switching member in the opposite direction; ratchet means for effecting the progressive rotation of said cam to move said switching member in response to movement of said operating member to perform a switching operation; and snap-action means in addition to the cam and ratchet means for effecting rotation of said cam and movement of said switching member thereby in opposite directions with a snap action independently of the speed of movement of said operating member to effect both snap engagement and snap disengagement of said contacts.

5. An electric switch comprising: cooperating electric contacts; a rectilinearly movable switching member for controlling the engagement and disengagement of said contacts; a movable operating member; a rotary cam for effecting rectilinear movement of said switching member; means for effecting rotation of said cam to move said switching member in response to movement of said operating member to perform a switching operation; and snap-action means in addition to said cam for effecting rotation of said cam and movement of said switching member thereby in opposite directions with a snap action independently of the speed of movement of said operating member to effect both snap engagement and snap disengagement of said contacts, said snap-action means including spring-biased detent means independent of said switching member and socket means in addition to said cam receiving said detent means to effect snap movement of the cam member after it has been moved through a dead-center position by said operating member.

6. An electric switch comprising: a rectilinearly movable operating member; means biasing said member for movement in one direction; cooperating electric contacts; a rectilinearly movable switching member for controlling the engagement and disengagement of said contacts; a rotary cam for effecting movement of said switching member in one direction; biasing means for moving said switching member in the opposite direction; ratchet means for effecting the progressive rotation of said cam to move said switching member in response to movement of said operating member to perform a switching operation; and snap-action means in addition to said cam and ratchet means for effecting rotation of said cam and movement of said switching member thereby in opposite directions with a snap action independently of the speed of movement of said operating member to effect both snap engagement and snap disengagement of said contacts, said snap-action means including spring-biased detent means independent of said switching member and socket means in addition to said cam receiving said detent means to effect snap movement of the cam in each switching operation after it has been moved through a dead-center position by said operating member.

7. An electric switch comprising: a rectilinearly movable operating member; means biasing said member for movement in one direction; an operating arm pivoted on said operating member; a rotary cam; means for engaging said operating arm with said cam to effect rotation thereof; cooperating electric contacts; a switching member for controlling the engagement and disengagement of said contacts; said rotary cam controlling the position of said switching member to perform switching operations; and snap-action means in addition to the cam for effecting independent rapid rotation of said cam in each switching operation after it has been moved through a dead-center osition by said operating arm to effect both snap engagement and snap disengagement of said contacts.

8. An electric switch comprising: a rectilinearly movable operating member; means biasing said member for movement in one direction; an operating arm pivoted on said operating member; a rotary cam; means for engaging said operating arm with said cam to effect rotation thereof; cooperating electric contacts; a switching member for controlling the engagement and disengagement of said contacts; means guiding said switching member for rectilinear movement; means biasing said switching member against said cam so that its position is controlled by the cam surface engaging therewith; said rotary cam controlling the position of said switching member to perform switching operations; and snap-action means in addition to the cam for effecting independent rapid rotation of said cam in each switching operation after it has been moved through a dead-center position by said operating arm to effect both snap engagement and snap disengagement of said contacts.

9. The electric switch as defined in claim 7 in which said snap-action means includes a substantially cruciform member rigid with the rotary cam, and at least one spring-biased detent independent of switching means movable into the pockets between the arms of said substantially cruciform member to effect snap actuation of the cam.

10. The electric switch as defined in claim 7 in which said operating arm is connected to said rotary cam with a lost motion connection operable in both directions to effect rotation of the cam in opposite directions to effect switching movement of said switching member; and in which the lost motion connection provides for snap operation of the rotary cam in both directions after it has been moved through a dead-center position.

11. The electric switch as defined in claim 1 including: a push-button on the end of said operating member; a bulb socket in said operating member; an electrical conductor electrically connected to the biasing means for said operating member to establish an electrical circuit to said bulb socket, said biasing means comprising a spiral spring; a second spiral spring mounted interiorly of said first spring and insulated therefrom; a second electrical conductor electrically connected to said second spring; and means on said second spring presenting a central bulb contact terminal for a bulb disposed in said socket.

12. A push-button electric switch comprising: a rectilinearly movable plunger; a manually engageable pushbutton on one end of said plunger; a bulb socket mounted in said plunger for the reception of a bulb to illuminate the push-button; a first compression spring biasing said plunger in an outward direction; cooperating electric contacts; a switching member for effecting engagement and disengagement of said contacts; operating means between said plunger and said switching member for efiFecting switching movement of the switching member in response to movement of said plunger; a conducting connector leading from an exterior terminal portion to said spring and electrically connected thereto to connect said bulb socket to said terminal; a second compression spring; an electrical connector leading from an exterior terminal portion to said second spring and electrically connected thereto; and means on said second spring insulated from said plunger and first spring for engaging a bulb contact mounted in said socket to complete the circuit to the bulb filament.

13. A push-button electric switch comprising: a rectilinearly movable plunger; a manually engageable push button on one end of said plunger; a bulb socket mounted in said plunger for the reception of a bulb to illuminate the push-button; a first compression spring biasing said plunger in an outward direction; cooperating electric contacts; a switching member for effecting engagement and disengagement of said contacts; operating means between said plunger and said switching member for effecting switching movement of the switching member in response to movement of said plunger; a conducting connector leading from an exterior terminal portion to said spring and electrically connected thereto to connect said bulb socket to said terminal; a second compression spring;

an electrical connector leading from an exterior terminal portion to said second spring and electrically connected thereto; and means on said second spring insulated from said plunger and first spring for engaging a bulb contact mounted in said socket to complete the circuit to the bulb filament, said second spring being mounted coaxially of said first mentioned spring but in spaced relation thereto and being compressed therewith upon inward movement of the push-button and plunger to perform a switching operation.

14. A push-button electric switch comprising: a rectilinearly movable plunger; a manually engageahle pushbutton on one end of said plunger; a bulb socket mounted in said plunger for the reception of a bulb to illuminate the push-button; a first compression spring biasing said plunger in an outward direction; cooperating electric contacts operated by said plunger to perform a switching operation; a conducting connector leading from an exterior terminal portion to said spring and electrically connected thereto to connect said bulb socket to said terminal; a second compression spring; an electrical connector leading from an exterior terminal portion to said second spring and electrically connected thereto; and means on said second spring insulated from said plunger and said first spring for engaging a bulb contact mounted in said socket to complete the circuit to the bulb filament.

15. The electric switch defined in claim 7 in which the cam surface is shaped so that rotation of the cam prior to its snap-action movement in each switch operation efiects substantially no movement of the switching member.

References Cited by the Examiner UNITED STATES PATENTS 2,996,593 8/61 McMains 200-159 3,047,698 7/62 Walker 200 153 3,084,239 4/63 Horvath et a1. 200--156 BERNARD A. GILHEANY, Primary Examiner. ROBERT K. SCHAEFER, Examiner.

Claims

1. AN ELECTRIC SWITCH COMPRISING: COOPERATING ELECTRICA CONTACTS; A RECTILINEARLY MOVABLE SWITCHING MEMBER FOR CONTROLLING THE ENGAGEMENT AN DISENGAGEMENT OF SAID CONTACTS; A MOVABLE OPERATING MEMBER; A ROTARY CAM FOR EFFECTING RECTILINEAR MOVEMENT OF SAID SWITCHING MEMBER; MEANS FOR EFFECTING ROTATION OF SAID CAM TO MOVE SAID SWITCHING MEMBER IN RESPONSE TO MOVEMENT OF SAID OPERATING MEMBER TO PERFORM A SWITCHING OPERATION; AND