US2115069A - Electric switch and contact therefor - Google Patents

Description

April 26, 1938. A. HALL 2,115,069

ELECTRIC SWITCH AND CONTACT THEREFOR- Filed Sept. 27, 1935 5 Sheets-Sheet l ATTORN EY April 26,1938 A. HALL 2,115,069

ELECTRIC SWITCH AND CONTACT THEREFOR Filed Sept. 27, 1935 s Sheets-Sheet 2 INVENTOR g rl/raj" 170/1 ATTORNEY April 26, 1938. A, HAL L 2,115,069

ELECTRIC SWITCH AND CONTACT THEREFOR Filed Sept. 2'7, 1935 3 Sheets-Sheet 3 INVENTOR ATTORNEY Patented Apr. 26, 1938 UNlTED STATES PATENT OFFICE Arthur mu, Indianapolis, Ind., assignor, by

mesnc assignments, to P. R. Mallory 85 Company, Inc., Indianapolis, Ind., a corporation of Delaware Application September 27, 1935, Serial No. 42,370

11 Claims.

This invention relates to electric switches.

An object of the invention is to produce an improved switch for opening and closing electrical circuits, changing circuit connections and the like.

Another object of the invention is to provide improved contacting means whereby better electrical connections may be obtained.

A further object is toimprove the structure of an electric switch whereby greater durability,

. better performance and greater adaptability may be obtained.

Other objects of the invention will be apparent from the following description and accompanying drawings taken in connection with the ap- .pended claims.

' The invention may preferably be embodied in a switch having two or more operating positions for controlling a plurality of circuits. The switch may comprise a stationary member carrying a group of fixed contacts and a movable member carrying a group of movable contacts for co-opcrating with said fixed contacts. The movable contacts according to the present invention may preferably be mounted on spring arms and in some instances may be movably or adjustably held by said spring arms so as to accommodate themselves to the various aspects of the fixed contacts. The movable contacts may likewise be arranged so as to provide sliding contact with the fixed contacts in order to obtain better electrical contacting.

According to another aspect of the present invention a plurality of switch members may be detachably secured together so as to permit ready assembly and disassembly in the presence of other equipment.

The invention accordingly comprises the features of construction, combination of elements, arrangement of parts, and-methods of manufacture referred to above or which will be brought out and exemplified in the disclosure hereinafter set forth, including the illustrations in the drawings, the scope of the invention being indicated in the appended claims.

For a fuller understanding of the nature and objects of the invention as well as for specific fulfillment thereof, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

Figure 1 is a face view of a switch embodying features of the present invention and having parts broken away to better show the structure thereof Figure 2 is a section on the line 2-4 of Figure 1;

Figure 3 is a detail view showing one of the stationary contacts and its supporting structure;

Figures 4, 5, 6, and 7 illustrate various positions of the contacts during operation of the switch;

Figure 8 shows a modified stationary contact member;

Figure 9 shows the relationship of the stationary and movable contacts where the stationary contacts are of a modified form;

Figure 10 is a face'view of a modified switch;

Figure 11 is a section on the line li-ll of Figure 10;

Figure 12 is a face view of another modified switch;

Figure 13 is a section on the line i3-|3 of Figure 12 Figure 14 is a section illustrating certain of the contacts of the modified switch and is taken on the line lll4 of Figure 12;

Figure 15 is a section illustrating a means for joining a pair of switch units together by means of a shaft;

Figure 16 is a section on the line Iii-i5 of Figure 15;

Figure 17 is a section on the line ll-i'l of Figure 15;

Figure 18 is a section on the line l8--i8 of Figure 15; and

Figure 19 is an exploded view illustrating th method of coupling the switch shafts.

like reference characters denote like parts in the several figures of the drawings.

While a preferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the method of procedure and the construction of parts without departing from the spirit of the invention. In the following description and in the claims, parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

Referring to the drawings, a switch It is shown in Figures 1 and 2 having a rotor H and a stator or stationary member II. The stator 12 consists of a base 13 comprising a sheet plate or disc of insulating material punched. or formed with a suitable annular series of holes I4 and an annular series of teeth or projections i5 about its periphery and a central circular hole ii to accommodate the other parts of the switch structure.

A metal ring member I! is positioned over disc I! with its hole in register with the hole it in disc l3. Ring i8 is provided with a pair of oppositely disposed external tongues i9 and bent to be perpendicular to the body of ring i8. Tongue i9 is bent down toward the disc 13 and fits into a positioning hole in disc 13 whereby movement and rotation of ring it is prevented. Tongue 2B is bent up away from disc 83 and serves as a stop member for the rotor as will be more fully described later.

A tubular externally-threaded bushing ii is fitted snugly into hole it in the insulating disc i3 and the hole provided in ring 58. A solid integral flange is provided on bushing ill on one side of the disc i3 and another flange on the other side is spun over the edge of the hole in ring it to secure the ring it, disc i3 and bashing fl'l firmly and securely together.

Secured around the peripheryof disc i3 are contact members 26 comprising fiat metai strips each having a centrally located contact 22, an end 23 for securing the contact member to the disc l3, another end having an intermediate hole for receiving one of teeth it on the periphery of disc 93 and a connecting portion 26 at the extreme end for connecting the switch contacts to external circuit wires or conductors.

Contacting portions 22 are preferably formed by stamping up a boss from the contact strip 2 i.

In its preferred form the contacting surface is of a Wedge-shape having a pair of relatively fiat wedge faces forming an obtuse angle with each other at the center or apex of the contact. The base of the contact may be circular at its periphery.

End portions 24 have a bend at the edge of disc i3 so that holes 25 in the contact members receive teeth E5 in the edge of the disc, the teeth i3 thereby holding the contact members in place and preventing the ends 26 from being torn loose from the edge of the disc. End portions 23 of the contact members are extended through holes M in disc 63 and bent over on the reverse side of the disc to hold each of the contact members 2! in place.

The ends 24 of the contact members may be bent at any required or convenient angle to the base and provide soldering terminals 26 for connecting the external conductors.

The switch rotor il comprises a control shaft 30 mounted to rotate within bushing H. The end of shaft 30 which extends above base disc I3 is provided with a reduced tip upon which are fitted in superposed fashion a small disc or dish-shaped metal stop member 3|, a spring-metal spider 32, a bakelized or resin-impregnated paper disc 33 of substantially the same diameter as disc l3 and a metal washer 34. The end of shaft 30 is flowed or peened over thereby uniting members 30, 3|, 32, 33, and 34 into a unitary assembly.

The spider 32 is provided with spring arms 35 each having a circular hole in its end. Fitted against-the under side of each of said arms 35 is an insulating washer 36 having a reduced portion 31 fitted within the hole in the arm. Washer 36 may be of fibre, -bakellte", ceramic or the like.

. 38 to be loosely held within and beneath the washer 36 with its rounded contacting surface in contact with the fixed contacts 22 and the conical, portion resting against the edges of the hole spider 32 under compression to provide pressure between the movable and fixed contacts. The

movable contacts 38 are thus held normally in the valley between two adjacent fixed contacts 22m and 22b and in contact with both as shown in Figure 4. A circuit is thereby completed from contact 22a. to 222.

Upon rotation of the shaft 30, as by a knob secured to the free end thereof, the contact will tilt as shown in Figure 5 to face fixed contact 2212 toward which it is moved by the rotation of the shaft. After the contact 38 passes the apex of contact 22b it itllts in the opposite direction as shown in Figure 6. Upon further rotary movement of the shaft and spring arms the contact 38 is moved into touching contact with a third fixed contact 220 as shown in Figure 7. Upon a slight further movement the contact reassumes an upright position (relative to disc l3) and in so doing slides on contacts 22?) and 220. This sliding contact effects a cleaning of the contact surfaces and insures a good electrical connection.

It will be noted that the contacts themselves 80 serve as indexing means to hold the switch in its difierent operating positions.

Stop member 3| has a small sector cut from its periphery to receive upturned tongue 20. Tongue 2t thereby serves as a stop member for the rotor, preventing rotation thereof beyond that shown in Figures 4, 5, 6 and 7. it is thus seen that in the switch illustrated the movable contacts can be shifted back and forth to electrically connect contacts 22a and 22!) together or contacts 22b and 220 together. In the form illustrated 6 movable contacts are provided and 18 stationary contacts, 3 stationary contacts being individual to each movable contact.

Paper disc 33 is provided primarily to prevent soldering materials used in connecting conductors to terminals 28 from reaching the contacts during the soldering operation. Disc 33 serves to some extent also to prevent other extraneous materials from reaching the operating parts of the switch. Whenever desired, as after disc 33 has served its usefulness, it may be removed by tearing the narrow areas 43 connecting it to the rotor assembly at the center.

Figure 8 shows a modified stationary contact member 44 having a pair of ribs 46 on its projecting end portion to strengthen it and prevent bending.

Figure 9 shows the arrangement of the contacts where the stationary contacts 46 are provided with round or oval heads instead of wedgeshaped ones. I advantageous wiping contact is obtained whereby a good electrical connection is always insured.

It will thus be seen that a switch is provided which insures wiping contact each time the switch is operated, in which the contacts themselves serve as the indexing mechanism, in which the stationary contact members are securely fastened to the edge of the base disc and held against any possible tearing-loose of the terminals, and in which the contacts are protected from soldering materials and the like.

The stop members 26 and 3| may be eliminated,

With this arrangement the same if desired, thereby providing a switch which can be rotated continuously in either direction.

In the modification shown in Figures 10 and 11 the switch 50 is similar in general to switch Ill, previously described. Stationary contact members 2| are the same as already described. Two modified stationary contact members are substituted for members 2| in two diametrically opposite positions on the base l3. Members 5| differ from members 2| in having a small integral contact ear or lug 52 projecting up from the face of each member 5| at positions near the periphery of the base l3.

The rotor 53 of switch 55 has four spring arms 35 of the type previously described spaced to co-operate with the oval contacting surfaces 54 on contacts 2| and 5|. Rotor 53 carries in its pile-up, in addition, a strip member 55 providing two arms 55 provided with contacting portions 51 on their ends arranged to co-operate with contact lugs 52 on contacts 5|. Contacting portions 55 are provided with rounded or inclined ears 58 to allow the contact portions 51 to ride up onto the lugs 52 when the switch is turned.

Member 55 provides a means for connecting the two stationary contact members 5| together electrically when the switch is in the position shown in Figures and 11. Where switch-551s used for connecting elements into a circuit, such as for connecting radio coils into the circuit of a radio receiving set, the member 55 may be used, for example, to short-circuit or to ground the coil or other element when not in use. It will be obviousthat additional members 55 may be added to the switch 55 and contact members 5| substituted for members 2| to provide for con,- tact with other pairs of positions.

Figures 12, 13, and 14 illustrate a further modified switch 50 having a stator similar in general to that previously described having the contact positions fitted with contact members 5| having upturned contact lugs 52. The rotor 5|, however, is provided with an assembly of parts held in superposed relation on shaft 30 comprising stop member 3|, a two-armed spring metal spider 52, a washer 53, an insulatory rotor disc 54 and a top washer 34. The circular holes in the two arms of spider 52, instead of carrying metal contact rivets, as in the previous switches, carry buttons 55 of insulating material, suitably bakelite, which serve only as indexing means and not as contacts. Buttons 55 are snugly fitted into the holes in arms 52 since no rocking of the rivet is required. The rotor contacts comprise a plurality of contact arms 55 riveted to the face of disc 54 and provided with contacting ends 51 having inclined ears 58 and arranged to contact with lugs 52 on the stationary contacts 5|. Flexible leads 59 provide electrical circuit connections for rotor contacts 55. It will be obvious that insulatory indexing buttons 55 will co-operate with portions 22 of stationary contacts 5| to bring about accurate registry of the contact arms 55 with contact lugs 52. It is practically impossible for the switch to be stopped in an open-circuit position.

Figures to 19, inclusive, illustrate the meth- 0d of connecting the shafts of two or more switch units together for gang operation. In this arrangement the switch shafts are of modified construction. The rotor and stator elements may be of any of the types previously described.

As shown in the figures switch unit 10 may be provided with threaded bushing H for mounting in a panel or the like and shaft 1| of this unit is flattened at end 12 for attachment of a control knob. The other end 13 of the shaft has a U- shaped spring clip 14 secured to it, clip 14 having two co-operating spring arms 15, 15 adapted to retain a flat shaft between them and shaft 1| has a slot 15 cut in its end to receive such a shaft.

Switch unit 15, arranged to be ganged with unit 10, is provided with a round shaft 11 and a flat extension shaft 18 permanently secured to it. Round shaft 11 is preferably very short and flat shaft 18 is preferably of a length substantial-- ly equal to the spacing desired between units 15 and 15.

Flat extension shaft 18 is staked or secured to round shaft 11 in the following manner. Round shaft 11 is slotted at its end at 19 to receive shaft 18 and is also cut away at the sides to reduce its thickness adjacent the end. Shaft 18 is provided with a hole 80 near its end. After the shafts 11 and 18 are fitted together parts of the end of shaft 11 are upset into hole 80 to permanently fasten the two shafts together.

The two units can readily be fitted together whenever desired by merely slipping the free end of fiat extension shaft 18 into clip 14 and slot 15 in the end of shaft 1|. This arrangement makes it possible to interpose other equipment between the two switch units with ease. After the first switch unit has been mounted in position in a radio set or other assemblies, for example, it is possible to mount other devices, such as condensers, coils and the like in the spaces 8| and to attach the second switch unit by the extension shaft 18 after the other devices are in place. This feature allows great flexibility in the switching arrangements as well as greater ease'in assembly than heretofore.

While the present invention, as to its objects and advantages, has been described herein as carried out in specific embodiments thereof, it is not desired to be limited thereby but it is intended to cover the invention broadly within the spirit and scope of the appended claims.

What is claimed is:

1. A contact member consisting of a rivet of conducting material, said rivet having a convex head, a cylindrical shank and a conical portion between said head and said shank, the larger base of said conical portion being nearest said head.

2. A contact member comprising a rivet of conducting material, said rivet having an outwardly rounded head, a tapered portion having its larger base at the base of said head, and a shank portion projecting from the smaller base of said tapered portion.

3. In an electric contact device, a sheet of insulating material having an integral projecting tongue in the edge thereof, and a contact member comprising a fiat metal strap secured to a face of said sheet with an end of said strap bent down over the edge of said sheet, said strap having a hole for receiving said tongue.

4. In an electric contact device, a sheet of insulating material having a hole therein and an integral projecting tongue in the edge thereof, and a contact member comprising a flat metal strap having one end thereof passing through said hole and the other end thereof bent down over the edge of said sheet, said strap having a. hole for receiving said tongue.

5. In an electric contact device, a sheet of insulating material having an integral projecting tongue in the edge thereof, and a contact member comprising a fiat metal strap secured to a face of said sheet with an end of said strap bent down over the edge of said sheet, said strap having a hole for receiving said tongue, and re-enforcing ribs on the part of said strap extending beyond the edge of said sheet, whereby bending and tearing loose of said contact member is effectively prevented.

6. An electric switch comprising, in combination, an insulating disc base, a rotor shaft passing therethrough, a resilient arm secured to said rotor shaft, a rivet-like contact, a receptive socket on said resilient arm of larger internal diameter than the shank of said contact, said contact shank being loosely held in said socket, a stationary contact on said disc base, the face of said rivet contact being adapted to make contact with said stationary contact, a stationary lug electrically connected to said stationarycontact and a second arm secured to said rotor shaft and adapted to make contact with said lug.

7. In an electric switch a plurality of convex rounded fixed contacts, a movable control member having a socket, a contact rivet loosely held within said socket and having a convex face adapted to move over the convex faces of said fixed contacts and make sliding contact therewith, an upstanding lug connected to one of said convex fixed contacts and a contact member movable with said control member and adapted to make contact with said lug.

8. An electric switch comprising, in combination, an insulating discbase, a rotor shaft passing therethrough, a resilient arm secured to said rotor shaft, a rivet-like contact having a head, a shank and a tapered portion between said head and shank, a receptive socket on said resilient arm of larger internal diameter than the shank of said contact but of smaller end diameter than the base of said tapered portion, whereby .said contact shank is loosely and rockably held in said socket, a stationary contact on said disc base, the face or said rivet contact being adapted to make contact with said stationary contact. i

9. An electric switch comprising a plurality of convex fixed contacts, a movable control member having a socket, a contact member comprising a rivet of conductive material, said rivet having a convex head adapted to be moved over said fixed contacts, a tapered portion having its larger base joining said head and of larger diameter than said socket and its smaller base of smaller diameter than said socket, and a shank portion projecting from the smaller base of said tapered portion.

10. An electric switch comprising, in combination, a series oi convex fixed contacts on a base and a movable member adapted to move over said fixed contacts, said member comprising a red surface of said shank rests against the i'ality of fixed contacts secured to said base and disposed in a circular arc thereon, said fixed contacts having a raised convex portion forming a circular series of projections on one face of said base, a rotatable shaft passing through said base, a flexible arm secured to said shaft, a socket of insulating material held by said arm so as to travel over said fixed contact projections, said socket having a cylindrical opening therein with the axis of said opening substantially parallel to the axis of said .shaft, and a movable contact rivet held in said socket, said rivet comprising a convex head portion, a cylindrical shank portion and a tapered portion between said head and shank portions, said head portion making contact with said projections of said fixed contacts and said tapered portion resting against the edges of said socket.

ARTHUR HALL.

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