US2506196A

US2506196A - Electric switch

Info

Publication number: US2506196A
Application number: US25192A
Authority: US
Inventors: Bourne William George
Original assignee: Rotax Ltd
Current assignee: Lucas Support Services Ltd
Priority date: 1947-05-08
Filing date: 1948-05-05
Publication date: 1950-05-02
Anticipated expiration: 1967-05-02
Also published as: FR966105A; GB623514A; DE829759C

Description

May 2, 1950 w. G. BOURNE ELECTRIC swI'rcH Filed May 5, 1948 Patented May 2, 1950 ELECTRIC SWITCH William George Bourne, London, England, assignor to Rotax Limited, London, England Application May 5, 1948, Serial No. 25,192

- In Great Britain May 8, 1947 2 Claims.

This invention relates to electric switches of the tumbler type. These switches are known in many different forms, and are adapted to operate in a number of different ways, all depending on the actuation of a pivoted finger lever. In some switches the movement of the finger lever from one limiting position to another serves to open or close a single electric circuit, or to open one circuit and close another. Or, with the lever normally occupying a central position, control of either of two circuits is effected by moving the lever to one side or the other of the said position. Moreover, in some switches the lever is held by the action of a spring in the position to which it has been moved, in others it is automatically returned by a spring to its initial position when the finger lever is released. Hitherto the provision of a range of switches individually capable of operating in any of the above-mentioned or other analogous ways, has involved much multiplication of component parts and consequent complication of manufacturing operations. An obviously desirable condition from consideration of economy of manufacture is that all the switches in a given range should employ as many similar components as possible, and the object of the present invention is to enable this condition to be met in a convenient and satisfactory manner.

In the accompanying drawings,

Figure 1 is a side sectional elevation of an electric switch of the tumbler type constructed in accordance with the invention and arranged for the control of either of two circuits by moving the finger lever to one side or the other of a central or neutral position; i l

' Figure 2 is an end sectional elevation of the switch'taken on the centre line' of Figure 1; v.

Figure 3 is a side elevation of a part of the switch mounting and rocker, with the cam piece omitted; I

Figure v4 is an elevation, partly in section, of a portion of the switch mechanism of Figure 1, provided with a modified form of cam piece;

Figure 5 is a view similar to Figure 4 showing another modified form of cam piece;

Figure 6 is a view similar to Figure 5 showing a further modified form of cam piece.

In carrying the invention into eii'ect according to one convenient mode as illustrated in Figures 1, 2 and 3, there is provided a sheet metal mounting l for carrying the finger lever and rocker of the switch. The mounting is of deep U-section having a pair of parallel sides which are wider at their upper ends, and which at their lower ends are joined by an integral cross part g, 7 At about 2 the mid point of each of the sides there is formed an aperture 3.

The rocker is a sheet metal part having a pair of arms 4 extending in opposite directions from its central portion, the outer end of each'arm serving as or having secured to it a contact piece 5. The central part 6 of the rocker is also 01 U-section and the upper ends of its sides are bent over at l (or are provided with pins) to engage the apertures 3 in the mounting l and serve as pivotal connections between the rocker and mounting, the rocker being located between the sides of the mounting as shown in Figure 2.

The finger lever may be of any convenient construction. Preferably it consists in part of a metal stem 8 which has a cylindrical bore 9 extending for a convenient distance from itsinner end, and in this bore is accommodated a helical spring I0 which bears on a metal ball I I inserted in the lower end of the bore, the ball serving as the abutment required to co-operate with the cam piece to be hereinafter described. This metal stem is encased from about its centre to its outer end by a sheath !2 of thermoplastic or analogous material, and the inner end of the sheath has moulded. on it a spherical part l3 adapted to occupy a corresponding seating M in a cover piece I 5. The cover piece is provided also with a slot l6 through which the outer end of the lever 8 extends. The central and inner parts of the'leverlie between the sides of the mounting I, and the central part is connected to the mounting by a pair of coaxial pivot pieces 41. The mounting l is secured to the cover l5 by screws l8.

On the rocker is mounted a separately made cam piece I 9, and it is the form of this piece that determines the mode of action of the switch. The combination of mounting, finger leverand rocker, serves for any switch in the range to be manufactured, the only component which is different for different switches being the cam piece. If itis required to provide a switch of the kind in which the finger lever occupies a midposition when the switch is open, and in which movement of the lever to either side of this position serves to close one or the other of a pair of circuits to be controlled by the switch, .the cam piece consists of a fiat metal piece as shown in Figures 1 and 2 having at the centre of its upper edge a recess 20 adapted to be engaged by the spring loaded ball ll above mentioned on the finger lever 8, and having at the opposite sides of the recess a pair of similar andupwardly inclined straight edges 2| on which the ball can act when the finger lever is moved. The under edges 22 ofthecam piece are adapted to seat firmly on the upper surfaces of the arms 4 of the rocker, and preferably it is provided with a central projection 23 which occupies a recess between the said arms, the cam piece being secured to the rocker by a rivet, cotter or the like 24 inserted through it and through the sides of the rocker 5. This cam piece is such that with movement o f' the finger lever to either side of central position the rocker is caused to move about its pivotal connection with the mounting under the action of the spring loaded ball I l on one of the inclined edges 2| of -t-heoam piece, and these edges are so designed that the rocker and the finger lever wili be 'moved automatically to circuit opening position as soon as the finger lever is released, the rocker then being held by the engagement of the ball with thereoess 20 in the cam piece.

As regards the remainder of the switch this may take a variety of forms. In the example illustrated there provided an insulating base 25 carrying a pair of contacts 26 for era-operating with the rocker "contacts 5. Ihe base may be secured to the mounting l by ascrew but preferably and asshow-n-a metal member '2! is moulded into the base and has aicylindrical'part =28 which riveted over a hole in the cross part 2 or the mounting. The cover piece I *is extended to form a wall -29 which encloses the base, and to the lower end'of this wall a second cover piece -35 is'secured by a screw 34 to enclose the underside of the base and the terminal connections provided on the base.

It will be seen that with the (arrangement described the finger lever may occupy a middle :or neutral position, or-may be moved to one side or the other to close either of two circuits, and will return automatically to said middle or neutral position as soon as positive pressure on thefinger lever 'is removed. I V

If it is required to provide a two way switch such that one of a pair of circuits to be controlled is closed when the other is open, the cam piece described in the previous example is replaced by a d'iiierent cam piece as shown in Figure 4. The cam piece 32 for this purpose is similar to the previously described cam piece l9 except for the shapeo'f its upper edge which has at its centre an inverted V-ridge '33 and .a straight edge 34 which is given 'a slight upward "inclination at either side of "the V-r'idge. With this foam piece in position the finger lever can only rest in one or other of inclined positions as shown in Figure '4, i. e. one '01 other of *th'e'circuits controlled by'the contacts 1'6 will alxxnrys *be closed. The construction of remainder cf 'the switch is the same as "described for the previous example.

For some purposes it is required that the lever shall occupy a central position when the switch is'open, and that when moved in'one direction from that position it shall close one of a pair of associated circuits, this circuit remaining closed until opened by positive movement of the linger lever in the reverse direction, but as regards the other circuit it is required that when closed it can remain closed only so long as the user exerts pressure "on the finger lever. This requirement is'met by the use of a modified form of cam piece as "shown in Figure 5. The cam piece 3% is similar so far asone half of it is concerhed to the cam piece of Figures 1 to 3; Thus there is provided a central depression 36 and on one side of it an inclined surface 31 arranged so when depressed the ball I] of the finger lever the latter will remain in position with the contacts closed only so iong 'as positive pressure is exerted on the finger lever, the finger lever and rocker returning automatically to circuit opening position as soon as such pressure is removed. On the other side of the depression 36 there is provided a gently inclined surface 38 (similar to the inclined surfaces 34 shown in Figure 4) so disposed that its interaction with the spring loaded 'ba'll H causes the finger lever and rocker to re- "main in position with the contacts closed until released by positive actuation. The construction or the remainder of the switch is the same as describedin connection with Figures 1 to 3.

For other purposes it is required that the switch shall remain in circuit closing position when the finger lever is moved to either side of the central position. This requirement is met by the use or the modified form of cam piece shown in Figure 6. The cam piece 39 is similar to the previously described cam pieces except for the shape of the upper surface thereof. There is provided a central depression 40 and a pair of gently in- =clined surfaces 4 pm either side thereof, these eeing disposed in a similar inannerto the surface -38 of the previously described example. The operation of the switch will be clear from the io'regoing description.

From the foregoing it will be seen that any of a variety of requirements can *be met by the use of an appropriately shaped cam piece, and it is to he understood that the invention is not limited to the examples specified. Further whilst in the Fioregoihg there has been described the application of the invention to double acting switches, it will be understood the same components may he used in single acting switches, the rocker being then provided with a contact 'at one only.

By this invention the manufacture of a range of different tumbler switches 'can be greatly simplified, as most of the components are the same @01- an the switches in the range, the only (or principal) component which is different in the different switches and which determines the action of the switch being the cam piece.

The invention is not, however, restricted to the particular construction of mounting, finger lever, rocker and 'cover piece above described, as these and other features may he modified to suit different requirements.

Having thus described my invention what I "claim as new and desire to secure by Letters Patent is: a

-1. An electric switch having .in combination a base piece, at least one fixed contact on said base piece, a coverpiece, a mounting of deep Liform secured at "its o en end to cover piece at its plos'ed end to said 'base piece, a finger lever extending through an aperture in said cover piece and carried by said mounting, -a movable contact piece in the form of a rocker also carriedhbyfsaid mounting and arranged to co-. operate with said fixed contact, a cam piece made separately from and rigidly'secured to said rocker so as to be movable therewith but incapable of movement relatively thereto, and a spring loaded abutment piece slidably supported by -the inner end of said finger lever and arranged in "contact with sa-id cam piece so "that movement of "said finger lever "is accompanied by movement 01 said cam piece and rocker.

2. An electric switch as claimed in claim 1, in which said rocker comprises a pair o'f contact arm's extending in opposite directions from and formed integrally with a central U shaped part which at its upper ends is provided with lateral projections engaging apertures in the sides of said mounting.

WILLIAM GEORGE EoURNE.

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

Number 6 UNITED STATES P ATENTS