US2202698A - Electric switch - Google Patents

Description

May 28, 1940.

l. R. LATT ELECTRIC SWITCH Filed Oct. 21, 1938 2 Sheets-Sheet l I I I I 1 1 1 u z Inventor: Isaac RLatte His 'Attorny May 28, 1940. 1. R, LATTA 2,202,698

ELECTRIC SWITCH Filed Oct. 21,' 1938 2 Shuets-Sheet 2 Inventorz Isaac: R Latt'a,

is ttohng.

Patented May 28, 1940 PATENT OFFICE ELECTRIC SWITCH Isaac R. Latta, Drexel Hill, Pa., assignor to General Electric Company, a corporation of New York Application October 21, 1938, Serial No. 236,269

4 Claims.

My invention relates to improvements in electric switches and more particularly to auxiliary switches whose circuit opening or closing movements or both have to be coordinated with ang other mechanism, for example a circuit breaker,

so as to establish closely defined Operating sequences. An object of my invention is to provide an improved electric switch whose circuit controlling movements can be closely adjusted 10 for coordination with other mechanisms without disturbing 'the mounting or assembly of the switch. Another object of my invention is to provide an improved multistage electric switch in which the circuit controlling movements of the 15 different stages can be independently and closely adjusted for definite sequences of operation with respect to each other and another mechanism. These and other objects of my invention will hereinafter appear in more detail.

In connection with the control of various devices, such as circuit breakers for example, it is often necessary to use auxiliary switches having one or more stages of contacts whose opening and closing movements have to be deflnitely and closely coordinated with the various phases of operation of the circuit breaker. Because of the indeterminate amount of lost motion necessarily involved in most circuit breaker and switch operating mechanisms, it is difiicult, except by an ex- 00 pensive process of cut and try involving disassembling, fitting and reassembling of the various parts, to Obtain the-desired nicety of sequence of circuit controlling Operations. In accordance with my invention, I eliminate these cut and try processes of disassembly, adjustment and reassembly and the cost associated therewith by a switch arrangement such that the desired nicety of adjustment or sequence of operation can readily be secured without disturbing the mounting 4. or assembly of the switch. Moreover, further in accordance with my invention, in case of a multistage auxiliary switch, this nicety of adjustment can be secured in each stage independently of the others and also without disturbing the mounting 4|. or assembly of the switch.

My invention will be better understood from the following description when considered in connection with the accompanying two sheets of drawings, and its scope will be pointed out in 50 the appended claims.

In the accompanying drawings Fig. 1 is a fragmentary plan view partly in section of a multistage switch embodying my invention; Fig. 2 is an elevation on the line 2- 2 of Fig. 1 showing lo One stage in the open circuit position; Fig. 3 is an elevation on the line 3-3 of Fig. 1 showing anotherstage in the closed circuit position; and Fig. 4 is a disassembled perspective illustrating different partsof one stage of the switch shown in Fig. 1. 5

The multistage switch shown in the accompanying drawings for the purpose of illustrating a practical embodiment of my invention comprises a switch framework for supporting the different contact stages. As shown, this framework includes two side members IB and H, which may take the form of channels, and suitable endconnecting members,-such as plates |2. In general these parts may be of metal, and in this case One end-insulating barrier |3 may be provided. A similar barrier at the other end will not be required as will hereinafter appear.

For' Operating the switch, I provide suitable Operating means, shown as a shaft H, which is journaled in the end plates l2 and which may be square in cross section for purposes hereinafter to appear. Longitudinal movement of the shaft Il may be prevented in any suitable manner, as for example by collars |4' suitably secured to the ends of the shaft and bearing against the end plate |3 or its equivalent. It will be understood by those skilled in the art that this shaft may be connected'to any mechanism; 'such as a circuit breaker Operating mechanism, so as to be actuated in response to the move- 39 ments thereof or the shaft may be manually operated by means of a handle secured thereto but not shown in the drawings.

In order to have each contact stage unitary, I provide a support I 5 which extends transversely of the side members through slots in the webs thereof. Each support is provided with a centrally disposed Opening |5' through which the' shaft H extends to provide a pivotal mounting for the support |5. Obviously any suitable number of these stages may be assembled by providing side frames IO, H and a shaft Il Of the necessary length. By making the support IS of suitable insulating material, it is possible to insulate the contact parts of each stage and the support also acts as an insulating barrier between stages. Likewise, as will appear from Fig. 1, the last stage support constitutes the necessary insulating barrier at one end thus eliminating the necessity for an insulating barrier |3 at each 50 end.

As shown, the contact mechanism comprises relatively movable cooperating contacts, such as one or more contacts IE, I'l, which are movably positioned On projecting portions |8 of the support G5 and one or more inter-connected cooperating stationary contacts E9 fixedly mounted on a projecting portion f'fi of the support 05. This construction provides ythe advantage of two brealrs in series, hut one movable and one stationary contact may he employed so far as my invention is concerned. In the arrangement shown, a fiexible lead 211 secures the movable contacts to a terminal member 22 which embraces the projection fltl on the support 05 and is stationary relatively to this support. In order to provide a forced movement of the movable contact both to and from the circuit closing position, it is resiliently supported in a cradle 23, which may be of channel form as shown, so that the terminal 22 and the lead 2G can be inserted between 'its sides. The resilient support of the movable contact may be provided by a spring 241 which is carried on-a projection of the movable contact provided with a combination bearing and spring restraining head `When the contact is assembled, this projection fits into a slot 26 in the cradle with the cradle next to the contact and the spring biasing the cradle and contact arm together.

For forclbly moving the contacts to and from the closed circuit position, there are provided suitable cam means mounted on the shaft lfl. The contact opening cam means may comprise a single cam il having one or more cam faces 28 which engage the projecting heads 25 associated with the movable contacts 06 and fll so as to separat'e these contacts, as will appear more clearly from Figs. 2 andd. The cam f'l thus constitutes a contact opening cam which forcibly moves each of the contacts lt from the closed circuit position to the open circuit position when the cam is in a predetermined position which in the stage shown in Fig. 2 happens' to be with the long dimension of the cam horizontal. For forcibly closing the contacts, there may be provided two cams 239i and td having cam faces 3l. These cams are mounted on the shaft |4 one on each side of the cam El. In the arrangement shown, one of these cams 29 engages a cam follower projection 322 on the Cradle associated With the movable contacts lt and the other cam 30 engages a cam follower 32 on the Cradle 23 associated with the movable cam fl' so as forcibly to move these cradles in opposite directions about their pivotal mountings on the support E5. This causes the engagement of the stationary contacts lt by the movable contacts IB and il when the cam faces 30 engage the cam followers 32. With the arrangement shown in Fig. 1, this occurs when the long dimension of the cams 3| is Vertical as will be more clearly apparent from Figs. 3 and e.

In order to provide an adjustment for effecting a desired contact controlling action at a given angular position of the shaft and, corollary to this, to provide a given sequence of Operations in a multistage switch, the shaft center openings 32', the cams zl, 29 and W may be made of a reentrant polygonal form such that the cams may be slipped over the shaft M in a desired angular relation. If the shaft is-a square shaft, as shown, then the holes in the oams may be of a regular eight-pointed star shape which will give adjustments in steps of 45 each. These adjustments, however, are, in general, obtained only by disturbing the mounting and assembly of the switch.

In order to obtain the desired coordination bez-,

tween circuit controlling operations and the a aeoaeoe angular position of the shaft HG and particularly refinements in such coordination without any olisturbance to the mounting or assembly of the switch, I provide an adjustment of the contacts which can be accornplished, vfor example, Toy moving the support [15 relatively to the shaft Gil so that it is possible after assernbly of the switch and mounting thereof to change the points in the travel or rotation of the shaft at which circuit opening and closing movements of the contacts are effected. For this purpose, the support U5 may be provided with suitable actuating means such as a movable crosshead which engages the support 65 in any suitable manner as, for example, by a spheroidal head 3d projecting into a slot in one end of the support U5 Where it projects through the web of one of the channel members ltl. For moving the crosshead 33, there may be provided any suitable means such as a threaded member or bolt'i which passes through the flanges of the channel member w and engages the crosshead 33 which is suitably threaded for the purpose. The bolt 3% may normally be locked in position against movement by suitable means such as nuts il and the latter of which may be secured to the bolt as by a pin 38'. Upon Teaching od the nut 371 sumciently to permit the turning of the bolt 36 in one direction or the other, the crosshead 33 will be caused to travel along the bolt 36 whereby to Shift the suport [1h angularly with respect to the axis [Id in a direction dependent upon the direction in which the bolt is turned. Such a shifted position of the crosshead 33, the support i, and the bearing heads 34 is shown by the dash-dot lines in li'ig. 2. 0bviously, the greater the depth of the channel frame the greater the angular adjustment possible with the crosshead and screw mechanism. Inasmuch as each contact assem'bly has its own individual adjustment, it is obvious that any one of the contact arrangements can be adjusted independently of all the others so as to fit in with any desired sequence of operation of the other stages and to be adjusted to any given angular position of the switch within the range of movement of the crosshead adjustment, all without disturbance to the mounting or assembly of the switch. Switchesembodying my invention, accordingly, provide a compact, unitary structure whereby a rough adjustment may be obtained over the whole angular range of movement by fixeol steps of predetermined amounts with disassembly and reassembly of the switch and further refinements or nicety of adjustment can then be obtained over a desired angular range without the necessity of dismounting or disassembling the switch.

While I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arrangements shown, but seek to cover in the appended claims all those modifications that fall within the true spirit and s'cope of my invention.

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

, 1. An electric switch comprising a support, two cooperating contacts mounted on said support one stationary and the other movable relatively to the support, means for efiecting relative movement of said contacts including a shaft extending through said support and constituting a pivot for engular movement of the support and two cams mounted on said shaft for movement therewith one for-efiecting the circuit opening Jill movement of said contacts and the other for efiecting the circuit closing movement of the contacts; and means for turning said support on said shaft relatively to the Operating faces of said cams whereby to cause the circuit opening and closing movements of said contacts at different angular positions of the cams relati-vely to the support.

2. A multiple stage electric switch, each stage comprising relatively`-movable cooperating .contacts and a support of insulating material for said contacts each support constituting a barrier between successive stages of the switch, means for actuating said contacts including a common Operating shaft for all stages extending through said supports and constituting a pivot for angular movement of the supports and separate vactuating means for each stage carried by said shaft and movable therewith, and means for turning the contact support of each stage on said shaft relatively to the actuating means of thattstage and independently of the supports and actuating means of the other stages whereby to control the sequence of the circuit opening and closing movements of the contacts of all the stages.

3. A multiple stage electric switch, each stage comprising relatively movable cooperating conturningk the 'contact support of each stage on said shaft relatively to the Operating faces-of the cam means of that stage and independently of the contact supports and cam means of the other stages whereby to control the sequence of the circuit opening and closing movements of the contacts of all the stages.

4. Afimultiple stage electric switch, each stage comprising three cooperating contacts and a support of insulating material 'for .said contacts' two of said contacts being movably mounted on said support and the third contact being mounted intermediate the other two contacts for engagement by`both and ,each support constituting a barrier between successive stages of the switch, means for actuating said contacts including a common Operating shaft for all stages extending through said supportsand constituting a pivot for angular movement of the supportsand two cams for each contact stage mountable on said shaft 'in a plurality of different angular positions in the direction f rotation of the shaft one for positively effecting a circuit opening movement of said contacts and the other for positively effecting a circuit closing movement of the contacts vwhereby Ato control the sequence of the circuit opening and closing movements of the contacts of all the stages, and means operable after assembly of'the switch for turning the contact support of each stage on said shaft relatively to the faces of the cam means of that stage and independently ofthe supports and cams of the other=stages wherebytfurther to control the sequence of the circuit opening and closing movements of the contacts of all the stages.

i ISAAC R. LATI'A.

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