US2550145A

US2550145A - Electric slide switch

Info

Publication number: US2550145A
Application number: US71926A
Authority: US
Inventors: Melan M Geci
Original assignee: Stackpole Carbon Co
Current assignee: Stackpole Carbon Co
Priority date: 1949-01-21
Filing date: 1949-01-21
Publication date: 1951-04-24
Anticipated expiration: 1968-04-24

Description

April 24, 1951 M. M. GE CI ELECTRIC SLIDE SWITCH Filed Jan. 21, 1949 INVENTOR.

' BY 4 Q/ OW /IMM V ATTORNEYS.

M 2 m I K/ 4 .U .m n H nu 5 3% i 2 50%;: j L I IM\ "I F NHL IIII 6 M w 2 4 Patented Apr. 24, 1951 ELECTRIC SLIDE SWITCH Melan M. Geci, St. Marys, Pa., assignor to Stackpole Carbon Company, St. Marys, Pa., a corporation of Pennsylvania Application January 21, 1949, Serial No. 71,926

3 Claims.

This invention relates to electric switches, and more particularly to those in which a bridging contact is slid across a plurality of laterally spaced stationary contacts.

Slide switches of this character are well known, some having sliding contact members that are fiat and others using a ball as the moving contact. However, the flat contact requires a separate indexing member for holding it in bridging position, while a ball contact may not always make good electrical contact with the stationary contacts, due to rolling instead of sliding across them. Also, in an ordinary ball contact slide switch, in which an actuating button extends through a slot in the switch housing, the end of the slot serves as a stop for the button to keep the ball-carrying member from moving the ball beyond the on position of the switch and thereby opening the circuit. A disadvantage of such a switch is that, with the mechanical tolerances required in production, in most cases the end of the slot is beyond the point where it should be for stopping the ball in on position. The result is that the button moves past the on position before it strikes the end of the slot, so the ball-carrying member moves the ball out of engagement with one of the stationary contacts that it is supposed to bridge. This opens the circuit.

It is among the objects of this invention to provide a slide switch which operates smoothly at all times, which is simple and inexpensive in construction, which has self-cleaning contact surfaces, in which the sliding contact is held in bridging position without the help of a separate indexing member, and in which the sliding contact can be moved an appreciable distance without breaking its bridging contact with the stationary contacts engaging it.

In accordance with this invention a plurality of spaced stationary contacts project from the inner face of a base member in a line extending lengthwise of the base. A housing is mounted on the base and has a longitudinal slot in its top. A slidable actuator is disposed in the housing for movement longitudinally thereof and is provided with an actuating button projecting through the slot. The actuator also is provided with a socket having its open end facing the base member. head adapted to slide across the stationary contacts and to engage two of them simultaneously. The diameter of the head is great enough to permit the head to remain in engagement with a pair of the stationary contacts even though it is moved a considerable distance laterally on them. The movable contact also is provided with a stem extending from its head loosely into the actuator socket where a coil spring is located for pressing the head against the station- A movable contact member has a fiat ary contacts. The center of the head is provided with a detent that projects between the two contacts that happen to be bridged by the head at the time, in order to hold it in engagement with them. When the actuator is moved manually toward either end of the housing, the detent rifes over the terminal that is in front of it. By making the detent small enough to keep it from engaging two stationary contacts at the same time, the fiat head will be sure to slide on those contacts without lifting off from either of them.

The preferred embodiment of the invention is illustrated in the accompanying drawing, in which Fig. 1 is a plan view of my switch; Fig. 2 is a longitudinal section taken on the line IIII of Fig. l; and Fig. 3 is an end view of the switch.

Referring to the drawing, a housing is provided which is shown in the general form of a channel; that is, it has a web or top wall I and parallel flanges or side walls 2. The top Wall has extensions at its ends provided with openings 3 by means of which the switch is fastened in place to the desired support. Although this housing may be made of any suitable material, it is preferred to make it of metal and to provide the free edges of its side walls with lugs 4 which are bent over the edges of a base member 6 to position the latter in spaced parallel relation to the top of thehousing. The edges of the base member are provided with notches 1 for receiving the lugs in order to hold the base member in predetermined position lengthwise of the housing. The base member is made of insulating material, and mounted in it are three or more one-piece metal terminals, each ofwhich has a par-*ially spherical contact portion H held against the inner or upper face of the base, and a strip portion #2 extending through a slot in the base for connection to a wire (not shown) of an electric circuit. The stationary contacts I! are spaced apart in a straight line extending lengthwise of the switch.

Disposed in the housing between its top and the base member is an actuating member which is slidable lengthwise of the base and the housing. This actuator, which preferably is made of a molded insulating material, has a generally rectangular body it, from which an integral button ll projects outwardly through a slot l8 in the top wall of the housing. The opposite ends of this slot limit the longitudinal movements of the actuator by acting as stops against which the button abuts. The bottom of the actuator is provided with a longitudinally extending channel I9 into which raised contacts II project. The central portion of the actuator is provided with a socket 28 extending up into button I! and having its open lower end enlarged.

The center contact l i can be connected electrically with either of the end contacts by means of a movable bridging contact member which has a fiat, circular metal head 22 adapted to slide across the stationary contacts. The head is large enough to engage the tops of two of those contacts at the same time. Projecting from the center of the head is a short integral stern- 23 that extends up into socket so that when the actuator is moved back and forth in the housing it will carry the bridging contact along with it. The contact head is located in the enlarged lower end of the socket and is pressed against the stationary contacts by means of a coil spring 24 which is compressed between the head and the inner end of the socket.

To hold the actuator at either end of the housing, so that the sliding contact will not accidentally slide of? one of the end contacts H and thereby break the circuit, the center of head 22 on the side opposite to the stem is provided with an integral detent 25 which, preferably, is a small part of a sphere. This detent rides over the center contact when the actuator is moved back and forth, but the rest of the time it projects between that contact and the particular end contact that the head also is engaging. The detent is not large enough to engage both bridge contacts simultaneously, so it will not prevent the head from resting flat on them, nor keep the head fromsliding a limited distance against the stationary contacts. The sliding engagement of the flat head with the stationary contacts keeps their engaging surfaces clean so that good electrical contact will be maintained. The detent cannot move across the center contact without compressing the spring. This requires manual operation of the actuator and thus prevents the sliding contact head from accidently moving away from the end contact I i that it is supposed to engage. It will be observed that this sliding contact member is self-indexing. It does not require a separate element to hold it in position.

Another advantage of this switch is that continued movement of the actuator button I? toward and against the closer end of slot [8, after the contact head 22 has engaged a pair of the stationary contacts i I, will not move the head out of engagement with the contacts that it is bridging. This is shown in Fig. 2 of the drawings. assures engagement between the movable and stationary contacts even though slot 18 is a little longer than intended, because head 22 is large enough to remain in engagement with a pair of the stationary contacts in spite of appreciable lateral movement of the head.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. An electric switch comprising a housing having a longitudinal slot in its top, a base for the housing, a plurality of spaced stationary contacts projecting from the inner face of the base in a line extending lengthwise of the slot, a slidable actuatcr disposed in the housing for movement longitudinally thereof and provided with an actuating button projecting through the slot, the actuator being provided with a socket having its open end facing the base, a movable contact member having a flat head adapted to slide across the stationary contacts and to engage two of them simultaneously, said contact member also having a stem extending from its head loosely into said socket, and a coil spring encircling the stem and compressed between said head and the inner end of the socket for pressing the head against the stationary contacts, the center of said head being provided with a detent that projects between the two contacts bridged by the head to hold it in engagement with them.

2. An electric switch comprising a housing having a longitudinal slot in its top, a base for the housing, a plurality of stationary spherical contacts projecting fromthe inner face of the base in a line extending lengthwise of the slot, a slidable actuator disposed in the housing for movement longitudinally thereof and provided with an actuating button projecting through the slot, the actuator being provided with a socket having its open end enlarged and facing the base, a movable contact member having a fiat circular head in said enlarged end of the socket adapted to slide across the stationary contacts and to engage two of them simultaneously, said contact member also having a stem extending from its head loosely into said socket, and a coil spring encircling the stem and compressed between said head and the inner end of the socket for pressing the head against the stationary contacts, the center of said head being provided with a spherical detent that projects between the two contacts bridged by the head to hold it in engagement with them.

3. An electric switch comprising a housing having a longitudinal slot in its top, a base for the housing, a plurality of spaced stationary contacts projecting from the inner face of the base in a line extending lengthwise of the slot, a slidable actuator disposed in the housing for movement longitudinally thereof and provided with an actuating button projecting through the slot, the actuator being provided with a socket having its open end facing the base, a movable contact member having a flat head adapted to slide across the stationary contacts and to engage two of them simultaneously, said contact member also having a stem extending from its head loosely into said socket, and a coil spring encircling the stem and compressed between said head and the imier end of the socket for pressing the head against the stationary contacts, the center of said head being provided with a detent that projects between the two contacts bridged by the head to hold it in engagement with them, said detent being too small to engage two stationary contacts at the same time and said head being large enough to remain in engagement with both bridged contacts when the detent is in engagement with either of them.

MELAN M. GECI.

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

UNITED STATES PATENTS Number Name Date 1,256,546 Forth Feb. 19, 1918 1,799,920 Meuer Apr. '7, 1931 2,246,373 Lodge June 17, 1941 2,256,295 Schmid Sept. 16, 1941 2,348,519 Bolley May 9, 1944