US1971212A

US1971212A - Electric snap switch

Info

Publication number: US1971212A
Application number: US538036A
Authority: US
Inventors: Reamer Frank C De; William R Young
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1931-05-18
Filing date: 1931-05-18
Publication date: 1934-08-21
Anticipated expiration: 1951-08-21

Description

ug- 21, 1934- F. c. DE REAMER ET AL 1,971,212

ELECTRIC SNAP SWITCH Filed May 18, 1931 hmm...

I-nvenfor's 25 Q F'rcmk GDeReamer '32 j l l William R.You.ng 5 l/ @am l /al 50 l t/L/eOAv Their' Aforneg.

Patented Aug. 21, 1934 ELECTRIC SNAP SWITCH `Frank C. De Reamer, Bridgeport, and William R. Young, Fairiield, Conn., assignors to General Electric Company, a corporation of New `York Application May 18, 1931, Serial No. 538,03

3 Claims.

The present invention relates to electric switches of the snap or quick make and break type, and has for its object the provision of an improved and simplified construction. The invention is especially directed to small switches such as are used in connection with radio apparatus, small electrical appliances, motor car lighting, etc., but is not necessarily limited to such uses.

For a consideration of what we believe to be novel and our invention, attention is directed to the accompanying description and the claims appended thereto.

In the drawing, which is illustrative of our invention, Fig. 1 a perspective view of a switch on a greatly enlarged scale; Fig. 2 is a longitudinal sectional view of a single pole switch taken on line 2-2 of Fig. 3; Fig. 3 is a cross-sectional view, taken on line 3--3 of Fig. 2; Fig. 4 is a perspective view oi.' fixed and moving contacts for the switch of Fig. 2; Fig. 5 is a sectional view of a double pole single throw switch; Fig. 6 is a perspective view of fixed and moving contacts i or the switch of Fig. 5; Fig. '7 is a view partly in section of a roller contact; Fig. 8 shows a modified form of actuator; and Fig. 9 is an exploded view of the parts of said actuator.

In switches of the character herein referred to, simplicity of construction and ease of assembly are of paramount importance. Another factor of outstanding importance is the ability to withstand long and protracted use without injury. Further, as a manufacturing proposition it is highly important that the same parts may when properly assembled be used in a number of different types, or sizes of switches. These and other advantages are obtained in our improved construction.

8 indicates a base made of moldable insulating material of such character that it will withstand rough usage without breaking. As an example,

it may be `composed of a phenolic condensation product and a iiller.

i lar and has bottom, side and end walls, the top being open. It contains a central chamber or recess 9 in which the moving contacts are located,

and also four vertically disposed narrow slots 10, two at each end, which extend in parallel relation from the recess 9 t`o and through the en d walls. The slots are arranged in pairs in the saine longitudinal plane. For singlepole switches, as in Fig.

5o 2, only two of the four slots are used while all of the slots are used for double pole'switches, as in Fig. 5. This construction of the base is common to the various types of switches whether they be of the single pole, double pole, threeway or other type. The ends oi the recess denne shoulders.

It is substantially rectangu- In the construction shown in Fig.

2, one of these shoulders serves as a support for the stationary contacts, while the other acts as a stop `for the movable contacts when the latter are moved to open circuit position. In Fig. 5,

as will appear later, both shoulders are used to help support the contacts. At each end of the base is a narrow integral projection 11 having considerable depth which separates the exposed ends of the contacts and their circuit wires and prevents short circuiting. The base isV provided with a cover 12 made of insulation, and this in turn is cov-'fred a metal plate 13 which carries the actuatc t .'.or the'. movable contact or contacts. The base, cover and plate are permanently united by rivets 14 located at opposite ends of the base. The

parte

12 and 13 taken together may be regarded as a cover for the base. By using rivets instead oi' screws all danger due to parts working loose is avoided. It a switch fails for any reason it is better to replace it with a new one because of the low cost, attempt to repair it.

rather than to The stationary contacts 15 are punched from sheet stock and require no machine work. They are placed edgewise in the slots 10 and their thickness is only slightly less than the width o! the slot so that the walls of the latter will always hold the contact in an upright position with one edge presented to the movable contact. It is necessary, of course, to fasten these contacts in place, and to avoid the use of screws or like fastening means, each contact is provided with small tits or projections 16 and 17, one being on the top and the other on the bottom. The bottom projection 16 lits into a shallow recess 18 in the base, and the upper projection iits into a recess or pocket 19 in the cover 12. It the cover` is relatively soft the application of sumcient pressure to enlarge the heads of the rivets 14 will cause the projections to form its own re- CeSSeS.

If the cover is relatively hard the recesses may be formed at the time it is punched out of sheet stock. As shown in Figs. 2 and 4, the stationary contacts have shoulders 20 and beveled extensions 21 which engage the walls of the recess in the base and thus assist in rmly holding the contacts in proper position. To state the matter another way, the bottom edge oi the contact rests on the lower wall of the central recess or chamber; a second and vertical edge portion engages a vertical wall on the base; a third edge portion rests on a horizontal surface at the bottom of a slot, and finally the projections on the contact enter shallow recesses to further anchor the same in place.

The fact that each contact has a shoulder which engages a shoulder on the base means that the effect of the hammer-like blow of the moving contact is absorbed by said shoulders and not by the small projections, the area of which is quite small. Looking at the matter in another way, each contact has a two part seat, one part which absorbs the shock of the moving contact while the other part prevents movement in a vertical direction.

22 idicates one of the stranded circuit wires and 23 shows how the strands of the wire are secured in a dovetail in the contact by the application of pressure. The wires are secured to the contacts before the latter are mounted in the slots, which simplifies the assembly.

30 indicates a roller contact which when out of engagement with the stationary contact travels or rolls on the cam or track 31 formed on the insulating base. When the movable contact is in engagement with the stationary contacts it is raised slightly above the level of the track 31. The walls of the base and the track are cut away suiliciently at the region where arcing takes place between contacts to prevent burning of the instrlation, as best shown in Fig. 3. The rollers 30 are actuated by an insulating member 32 which is recessed at the bottom to partly encircle the axle of said rollers. The member 32 is slotted to receive the lower end of the actuator 33, the latter engaging a collar or washer 34 which in turn rests on a compression spring 35. The actuator has a suitable handle 36, the two being carried by a cross pin 37 located in the tubular fitting or nozzle 38. The fitting is screw-threaded to receive nuts by means of which the switch can be secured to a metal or other support such as a lamp standard, for example. As arranged, the actuator and part 32 form a toggle and the spring causes the contacts to move with a snap action both in closing and opening the circuits through the stationary contacts. The spring; also holds the roller contact in engagement with the track and stationary contact. Fig. 4 clearly shows how the roller contacts make engagement with the edges of the stationary contacts, and this arrangement is of particular importance since it permits of the use of very simple parts. Those portions of the stationary contacts upon which the moving contacts finally come to rest are raised above the level of the track 31 so as to ensure good contact between the parts. It will be observed that the actuator engages the axle ol the roller contact in the region between the rollers. This means that the roller as a whole is in effect pivoted about the actuator so that even though the fixed contacts are not in absolute transverse alignment nevertheless good contact will be established between the movable and stationary parts because the movable contact is free to adjust itself about the actuator as a. pivot. In the construction thus far described current flows from a wire into a stationary contact, thence to a roller, then through the axle to the other roller to the second contact and thence to the outgoing wire.

The switch shown in Figs. 5 to 'I is of the same construction as that described, with this difference, that two sets of stationary contacts are provided which are suitably shaped. In this

case contacts

36 and 37 form one side of the circuit and contacts 39 and 40 the other side. 'I'he circuit between each pair oi contacts is made and broken by rollers 4l and 42. In this instance the rollers are mounted on an insulating support or axle 43 so that the two rollers, while mechanically connected, are electrically separate. The left-hand edges 44 of

contacts

37 and 40, as best illustrated in Fig. 5, are backwardly inclined or beveled by a slight amount so that there is a tendency of the rollers to be wedged downwardly when pressed by the spring and thus insure good contact. In other words, the inclined or beveled surfaces tend to force the rollers downward on the extended and substantially horizontal ends of the stationary contacts 36 and 39. It is also to be noted that the said edges 44 are so positioned that when the rollers 4l and 42 are in contact therewith, the spring 35 is retained under considerable compression pressure. This is obtained by making the circuit closing stroke or movement of the rollers slightly shorter than the opening stroke where the rollers engage the vertical edge of the stationary contacts 36 and 39. Experience has demonstrated that this arrangement of parts is important as it ensures good contact at all times. When the movable contacts are in the position shown in Fig. 5 the circuit is closed between stationary contacts 36-37 and 39-40. When moved to the left, the circuit is interrupted. As the handle and actu ator for the contacts are the same as in Fig. 2. further description is unnecessary.

It is to be noted that the insulating base is the same in both types of switches, which makes for simplicity of construction and reduction in the number of necessary parts. In Fig. 5 the movable contacts are always in engagement with the left-hand pair of fixed contacts and hence the cam or track 31 is not relied upon to support them at any time although present as before.

The fact that the stationary contacts are held between the side walls of the grooves prevents side-wise movement thereof, and the further fact that they are anchored against longitudinal movement by the small projections 16 and 17 115 results in a very firm support therefor. Presenting the stationary contacts in edgewise relation to the moving contacts has the great advantage of extreme simplicity oi' construction, and the arrangement as a whole reduces the number of parts, which means low cost of production both in the way of material and labor of assembling. It is also to be noted that the whole switch mechanism is united by two rivets which are secured only after the parts are fully assembled.

In a switch of this character it isimportant to relieve the strain on the circuit wires tending to separate them from the stationary contacts. This is accomplished in a very simple manner. Those portions of the base which receive the heads of the rivets are cut back slightly so as to leave the center of the base flat and smooth as indicated at 45. Under the head of each rivet is located a member comprising a thin piece of metal 46, the head of which is enlarged and engages the shoulder 47 to prevent it from turning on the rivet. The member 45 extends upwardly and terminates in clamp 48 which surrounds and clamps both circuit wires. Due to this arrangement any direct pull on the wires is taken by the member through the clamp 48, as is also any sidewise pull on the wires. As assembled, each switch is provided with short lengths of wire permanently secured to the stationary contacts, and these wires are then spliced to other circuit wires or connected to xed terminals. Due to the construction described the user of the switch has no occasion to get at the interior parts, and the use of the end rivets 150 14 is intended to prevent anyone from obtaining access to the interior thereof.

In Figs. 8 and 9 is illustrated a modied form of the means for moving the contacts, the details of the base and stationary contacts being the same as previously described. The purpose of the modified arrangement is to permit of the switch being mounted on a vertical panel or support in such a manner that a knob may be used as. an oscillating handle. 50 indicates a sheet metal member which is shaped to partly embrace the insulating base and is secured in place by the same rivets which secure the cover parts referred to above. In the member is secured a sleeve 51 which is screw threaded to receive a clamping nut. Inside of the sleeve is an oscillating spindle 52 having a shouldered end to receive a knob. On the inner end of the spindle is an arm or actuator 53 which terminates in an enlarged end 54 which in turn rests on a washer 34. Between the washer and a shoulder on the insulating member 32 is a compression spring 35. Enclosing the actuating arm is a cover 55 which is secured in place by the same rivets which secure the cover parts. This arrangement has the additional `advantage that the parts can be assembled and tried by the assembler before the cover 55 is applied, and thus ensure proper assembly.

As previously stated, the roller contacts 3() move over the track 31 for a portion of their total movement and then engage and move on the stationary contacts. Owing to the shape of the ends of the stationary contacts, the rollers are elevated from the track and at the same time the active portion or surface of each roller is transferred from the inner to the outer end thereof, as will be seen from Fig. 3 Where the stationary contacts 15 are in line with the outer ends of the roller contacts. In addition to preventing burning of the base as and when arcing takes place, this arrangement has the advantage that any roughening of the rollers due to such arcing is confined to the outer ends while the in'ner ends remain smooth and hence undue wear of the softer material of the track 31 is avoided as the rollers travel back and forth.

Referring again to Fig. '1, the axle 43 which is made of insulating material has enlargedcylindrical ends of drum like form over the ends of which are applied thin metal ferrules or caps 41 and 42 forming the roller contacts. The inner ends of the ferrules are crimped inwardly at 56 to engage the edges of the drums. This affords an exceedingly simple and effective way for uniting the parts, and one which is cheap in manufacture. It also ensures the proper amount of insulation between the roller contacts or ferrules.

The specific means for fastening the circuit wires to the stationary contacts is not claimed herein, as it forms the subject matter of Letters Patent 1,888,850 issued November 22, 1932, to F. C. De Reamer.

What We claim as new and desire to secure by Letters Patent of the United States, is:

1. In a switch, the combination of a unitary base of insulation substantially box-shaped and having integral side, bottom and end walls, one of said end walls having a plurality of grooves of moderate depth therein, a raised track extending longitudinally of the bottom wall of said base, straight flat stationary contacts mounted edgewise in said grooves and engaged by the walls thereof, said contacts having depending L-shaped portions overhanging said end wall and depending into the interior of said box, the toe of said L-shaped portions extending along said track but spaced therefrom and tapering below the level thereof, a contact mounted to move back and forth on said track to engage the edges of said stationary contacts, cover means secured to the base for clamping the stationary contacts in said grooves and an actuator secured to said cover for moving said movable contact with a snap action. 100

2. In a switch, the combination of a unitary base of insulation substantially box-shaped and having integral side, bottom and end walls, one of said end walls having a plurality of grooves therein, a raised track extending longitudinally 105 of the bottom wall of said base, straight flat stationary contacts mounted edgewise in said grooves, said stationary contacts having portions extending into the interior of said body member along said track but spaced therefrom and taper- 110 ing below the level thereof, a contact mounted to move back and forth on said track to engage the tapering edges of said stationary contacts and an actuator for moving said movable contact along said track.

3. In a switch, the combination of a unitary base df insulation substantially box-shaped and having side, bottom and end walls, one of said end walls having al plurality of grooves of moderate depth therein, a raised track extending longitudinally of the bottom wall of said base, straight flat stationary contacts mounted edgewise in said grooves and having portions extending into the interior of said body member, a roller type contact mounted to move back and forth 125 on said track to engage the edges of said sta.- tionary contacts, an actuator for moving said movable contact along said track, the contacting surfaces of said stationary contacts being spaced from said insulating trackand out of line with 130 the portions of said movable contact engaging said track.

FRANK C. DE BEAMER. WILLIAM R. YOUNG.