US2724031A - Electric switches - Google Patents

Description

Nov. 15, 1955 w. w. MULTANEN 2,724,031

ELECTRIC SWITCHEI S Filed June 26, 1953 139 M I a,

W/LL/AM W MULTANEN INVENTOR HUEBNER, BEEHLER,

WORRE'L 8 HERZ/G ATTORNEYS Xian 2725M Unitfid States Patent ELECTRIC SWITCHES William W. Multanen, Shell Beach, Calif. Application June 26, 1953, Serial No. 364,228

1 Claim. (Cl. 200-155) This invention relates to electric switches and is more particularly directed to rotary switches of the general character usually referred to as panel switches.

Rotary switches of this general character are usually designed for mounting in an aperture formed in a supporting member such as a switch board, instrument panel, or the like but the instant switch is, of course, not limited to such operational environment.

In this art it is recognized that, in switches which make or break an electrical circuit by means of wipe contacts, contacts that engage and disengage with a wiping or sliding action, there is an ever present danger of creating an are which may and often doesfuse the contacts to such a degree as to render the switch ineffective. This is especially true in switches in which the switching action is relatively slow. Thus it is, that it has become increasingly desirable to use switches which employ lift contacts that have closing and opening movements toward and away from each other in a plane more or less perpendicular to the sliding action of the wipe contacts above referred to, and to favor snap switches employing the almost instantaneous action of pretensioned spring means of various forms such as, for instance, over-center springs or the like.

It is, of course, understood that various specific types of rotary snap switches have already been devised and that some of them have been sold in large numbers, however, it is recognized by those skilled in the art, that, many of these are so complicated as to frequently become inoperative and can be repaired only with considerable difliculty and at an appreciable cost. 'In fact, such cost at times renders it more economical to replace the inoperative switch with a new one rather than try to repair the old one.

' While the trade recognizes that many very satisfactory switches have been produced for certain specific uses where the matter of cost is of no particular import, it is fully cognizant of the pressing demand for along life, simple, and efficient switch which will be suitable for general use, which also may be easily connected or disconnected and repaired by unskilled labor, and which may be speedily and cheaply produced by ordinary factory methods. This matter of production cost is of exceptional importance in the highly competitive electric switch field.

Therefore, it is an object of the presentinvention to provide an efficient rotary snap switch in the operation of which the probability of creating an electric arc is reduced to a minimum.

Another object is to provide a rotary switch which includes make or break contact elements movable towards or away from each other with a snap movement, as distinguished from a wiping or sliding movement, and which dependably determine the respective on and off positions of the switch actuating means.

Another object is to provide a rotary switch which has I more than one off position and which can be rotated in either direction.

A further object is to provide alrotary snap switch which may be quickly and easily assembled and disassembled by unskilled labor.

Another object is to provide a rotary switch of the above character whichhas few parts, all of whichmay be speedily and cheaply produced by ordinary factory methods and equipment.

Various other objects and advantages will be more fully apparent from the following description of the accompanying drawing which form a part of this disclosure and which illustrate a preferred embodiment of my invention.

In the drawing:

Fig. 1 is a side elevation, partly in section, showing the rotary switch of the present invention mounted on a switch board, instrument panel, or like supporting means.

Fig. 2 is a vertical diametric section taken on of Fig. 1.

Fig. 3 is a transverse section taken on line 33 of Fig. 1.

Fig. 4 is a transverse section taken on Fig. 1;

Fig. 5 is an exploded perspective view of the component parts of the switch.

With particular reference to Figs. 1 and 2 of the drawing, it will be observed that the switch of the present invention, designated generally by the reference numeral 10, is adapted to be mounted in a round aperture or bore 11 formed in a relatively thin flat supporting member 12 or any other suitable mounting. This supporting member may be a switch board, instrument panel, lamp, electrical appliance, ora part of any other desired supporting structure.

The switch includes a stationary cylindrical barrel or body 13 having an axial bore closed by a front wall 14 and which, at its opposite or rearward end, is counterbored at 15, to define an abutment shoulder 16. This counterbore 15 is adapted to receive an externally screwthreaded tubular mounting sleeve 17 which, in the assembled switch, is tightly screwed into the counterbore 15 until its forward end engages the abutment shoulder 16. Both the body 13 and the sleeve 17 are preferably line 22 line 4-4 of formed of relatively hard insulating material, such as Bakelite or the like. While they are preferably shown as two separable members, it will be apparent that, from either a functional standpoint or as a matter of manufacturing cost, they could easily be made as an integral unit.

Disposed within the axial bore of the body 13 and of the mounting sleeve 17 and extending the full length thereof is an elongated relatively thin rectangular separator 18 of insulating material that divides the interior of said body and sleeve into separate compartments 19 and 20 adapted to receive the respective lead wires 21 and 22 of an electric circuit in which the switch is to be included.

Positioned within the axial bore of the body 13 and 'disposed on opposite sides of the separator plate 18 to engage therewith are metal semi-cylindrical clamp plates 23 and 24 of similar shape and size. These plates are each provided with a tapped bore 25 disposed perpendicular to the insulating separator .18 and adapted to receive a setscrew 26 which has a dual function of serving as a switch contact and as a means for clamping its associated circuit lead wire in place.

The exterior wall of the body 13 is provided with an annular groove 27, the bottom wall of which defines a switch actuating cam 28 of general equilateral contour. As clearly illustrated in Fig. 4 of the drawing, the preferred embodiment employs an operating cam 28 which is of square shape with well rounded corners 29.

in the assembled switch, align with, and. are adapted to receive, the respective setscrews 26.

When these setscrews 26 are fully screwed-in to clamp the respective lead wires 21 and 22 in place, their outer ends project outwardly slightly beyond the adjacent fiat sides of the square cam 28 of the body so as to serve as the stationary electric contacts of the switch.

There is provided a manipulating knob 30 which em- ;braces, and is mounted to rotate on, the stationary body 13. This knob is made of suitable insulating material yandhasa flat aft face 31 and a radially fluted parabolic outer surface affording a. good hand grip for manual operation of the knob. Projecting radially from the axial bore of the knob 30 is a keyway 32 which extends from the aft face 31 of the knob forwardly at least to a point aligned with the forward vertical wall of the annular groove 27 of the stationary body 13.

The movable contacts of the switch are in the form of a U,-shaped bridging conductor or yoke 33 made of relative thin resilient sheet metal stock and formed to provide vshown in Fig. 4 of the drawing.

When assembled, the rotary knob 30 is held in place on the yoke 33 by frictional engagement of the key-34 in the keyway 32 into which it is fitted and by frictional engagement of the knob on the body 13. The knob and the yoke are held in place on the stationary body 13 by the engagement of the arms 35, elbows 36, and fingers 37in the groove 27. Such assembly is conveniently effected by first placing the yoke 33 in the groove 27 with the fingers in spanning'relation to the cam 28 and then sliding the knob over the end of the body 13 and frictionally engaging the key 34 in the keyway 32. Disassembly is as quickly and easily effected by the reverse procedure.

In the preferred manner of assembling the several parts of the switch, the semi-cylindrical plates 23 are inserted within the bore of the body 13 in position to align their tapped bores 25 with the entrance bores which are formed in the body to receive the setscrews 26. These setscrews are then inserted through the annular groove 27 of the body and in their respective entrance bores thereof are screwed into the tapped bores 25 of their respective plates. The tubular mounting sleeve 17 is screwed tightly into the threaded counterbore of the body 13 to abut the shoulder 16 and the members thus assembled are mounted in the supporting panel 12 by inserting the sleeve 17 in the opening 11 in said panel to abut the inner end of the body against the panel surface. A washer 45 is slipped over the protruding end of the mounting sleeve 17 to engage the aft face of the panel 12 and a nut 46. is screwed on the sleeve and tightened to secure the body von the panel. With the body of the switch thus secured in place, the insulating separator 18 is inserted in the sleeve 17 and body 13 and the lead wires 21 and 22, which have previously had their insulation stripped from their terminal ends, are inserted into the respective compartments 19 and 20 to position said terminal ends between the separator 18 and the respective setscrews 26.

'These setscrews are now tightened to clamp the lead wires to the separator plate 18 and to thereafter serve as stationary switch contacts individually in electrical engagement with the lead wires.

.The yoke 34, which is to function as the movable contact of. the. switch mechanism is then mounted in the manner described with the fingers 37, by their inherent spring tension, gripping the opposite fiat sides of'the square cam portion 28 of the body whi e the switch is in the normal off position as shown in Fig. 4. With the yoke 34 thus positioned in the annular groove 27, the knob 3t) is mounted in the manner described.

Operation In the operation of the described switch from an ofF' position, in which the electric circuit is open, to an on" position, in which the electric circuit is closed, tie op erating knob is manually rotated and carries with it the terminal yoke to which it is keyed. It is appropriate to observe that the form of the switch shown has two oft" positions and two on positions and that it can be operatively rotated, in either a clockwise or a counterclockwise direction to either of these four positions. Thus, its existing condition, either ofi or on, is changed to the opposite condition by movement in either direction.

In rotating the switch from the oh? position illustrated in Fig. 4, ninety degrees to an on position,.the first forty-five degrees of such rotation cause the spring contact fingers 37 to ride up on the first approached opposite rounded corners 29 of the square cam 28 to flex said contact fingers and lift them from engagement with the opposed flat sides of the square cam, this flexing of the resilient contact fingers 37 resiliently resists movement of the knob. During the final forty-five degrees of the movement the energy of the spring contact fingers, as they are released from the restraint of the corners of the cam, tend to hasten the rotary movement and cause said fingers to drop directly upon the opposed setscrew contacts 26 with a rapid snap action to close the electric circuit, the engagement of the contact fingers with the setscrew contacts, is illustrated in Fig. 2 of the drawing which shows the switch in an on condition.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but'is to be accorded the full scope of the claim so as to embrace any and all equivalent devices and apparatus.

, Having'described my invention what I claim as new and desire to secure by Letters Patent is:

In a rotary switch, a stationary hollow cylindrical body of insulating material having an axial externally screwthreaded mounting sleeve and anexternal annular groove, the bottom wall of which is formed to define a substantially square cam having fiat sides and rounded corners and provided with radially disposed entrance bores in two of its opposed flat sides to communicate with the interior of the body, a diametric insulating partition dividing the interior of said body and sleeve into two longitudinal compartments to receive electric circuit wires, opposed clamp plates disposed within said body on opposite sides of said partition, each plate having a tapped bore adapted radially to align with one of the entrance bores of said, cam, opposed contact screws inserted in said annular groove and through the respective entrance bores. of the body and screwed into the aligned tapped bores of the respective, clamp plates and adapted to project into. the re spective compartments in position to clamp said circuit wires against the partition, the contact screws, when in clamping position, extending slightly beyond the adjacent fiat sides'of the cam, a manipulating knob rotatably mounted on the body and provided with ancinternal. keyway, a bridging conductor yoke having a key frictionally engaged in said keyway andv having resilient contact fingers straddling and pressed against said contact screws when the switch is in an on position or to press against the intermediate fiat sides of the cam when the switchis in an an position,

:; References Citedin the file of this patent UNITED STATES PATENTS

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