US2272759A - Electric switch - Google Patents

Description

Feb. 10, 1942. E. A. WILLIAMS, JR

ELECTRIC SWITCH Filed Sept. 18, 1941 T. u S m e Oi n tm w t A M Mn 6. i s a w H E Patented Feb. 10, 1942 ELECTRIC SWITCH Edwin A. Williams, Jr., Lansdowne, to General Electric Company,

New York Pa... assignor a corporation of Application September 18, 1941, Serial No. 411,267

9 Claims.

the fuse are possible. In order to avoid this dangerous possibility suitable current-limiting means may be provided in series with the fuse to limit the current to a value which the fuse can safely and satisfactorily interrupt. Since it is also frequently desirable to isolate a potential transformer for inspection, maintenance, repair, testing, etc., a disconnecting switch may be provided in series with the fuse and current-limiting means. As a matter of economy and safety,

the switch may be combined with the fuse or the current-limiting means in such a way that the closing of the switch necessarily connects the one or the other or both of these electric currentconducting devices in series with th high voltage winding of the transformer. For this purpose the device in question may be mounted on a composite blade structure having an intermediate insulated portion which is bridged by the device. Such a composite blade structure introduces problems of structural rigidity in order to prevent failure of the device which, in the case of resistance elements, usually consists of a ceramic core on which is wound resistance wire. The covering is usually ceramic or glass for outdoor use and asbestos or phenolic resin for indoor use. Th requirement for such rigidity of blade structure as will prevent bending or unde-f sired distortion of the device calls for a construction more involved than the continuous metallic blade and, accordingly, increases the cost. It is, therefore, necessary to have a blade structure which is sufficiently rigid and yet relatively simple and economical if the combination of a disconnecting switch and a device carried by the blade of the switch is used.

An object of my invention is to provide a disconnecting switch having a rigid composite blade structure which is relatively simple and economical to produce. Another object of my invention is to provide a-composite blade disconnecting current-conducting device such that any probable relative movement of the blade parts does not distort the device in any way dangerous to the structure or affecting the operation thereof. These and other objects of my invention will appear in more detail hereinafter.

In accordance with my invention, I provide a composite blade structure of the so-called "floating blade type in order to obtain the better contact engagement associated therewith. Further in accordance with my invention this composite blade structure comprises two members each formed by seating material lengths of the end portions of a relatively long and fiat insulating member against the web and between the flanges of two channel-shaped electric'current-conducting members which provide th desired contact surfaces for cooperating with the stationary contacts of the switch. Also in accordance with my invention I mount on the metallic end portions of the blade structur supporting brackets for the electrical device to be carried by the blade in such a manner that the brackets offer minimum resistance to bending about an axis at right angles to the opening and closing movements of the blade whereby any relative movement of the blade parts likely to occur will be absorbed by the yielding of the brackets themselves.

My invention will b better understood from the following description when considered in I connection with the accompanying sheet of switch structure with a mounting for an electric drawings, and its scope will be pointed out in the appended claims.

In the accompanying drawing, Fig. 1 is a side elevation of a disconnecting switch embodying my invention; Fig. 2 is a front view of the switch shown in Fig. l with certain parts omitted; Fig. 3 is a sectional elevation on the line 33 of Fig. 1; and Fig. 4 is a partial view similar to Fig. 1 showing a fuse mounting.

In the illustrated embodiment of my invention I have shown a disconnecting switch comprising two spaced stationary contacts 5 and 6 of the tongue type. As shown, these contacts are mounted on suitable insulators 1 and 8, respectively, and are provided with terminal portions 9 and I 0, respectively, for the connection of conductors H and I2, respectively.

For bridging the contacts Sand 6 in such a manner as to support an electric current-conducting device I3 in series with the contacts, I provide a composite blade structure having an intermediate section of insulating material. As shown, this blade structure comprises two chan.

nel-shaped metallic members H which are pivotally mounted back to back against the sides the contact I. The members I! may be of any suitable electric current-conductlng material, such as copper, for example. The pivotal mounting illustrated comprises a hinge bolt I! which extends through the contact retaining washers II and spring washers IT to provide the socalled floating blade" action for better contact engagement. The intermediate blade section of insulating material is shown as two insulating elements ll respectively having a material length at one end flrmly seated against the web and between the flanges of the pivotally mounted channel-shaped members ll. As will b clear from Fig. 3, the pivot bolt It extends through the insulating blade members IO, and the retaining washers II are so arranged as to help maintain the insulating members II in position against the channel-shaped members ll. The insulating members ll may be oi any suitable material such, for example. as a suitably impregnated laminated wood.

For engagement with the contacts t the composite blade member Iurther includes two channel-shaped metallic members it against the web and between the flanges 01 which a material length of the other end portions of the insulating elements II are respectively seated with the webs of the members ll back to back and movelements ll. For a floating blade action. the

two composite blade parts are secured together at their free ends by a through bolt which extends through the insulating elements ii, the channel-shaped members It, retaining washers 2| and spring washers 22. This bolt assembly also helps to maintain the insulating elements ll flrmly seated in the channel-shaped members II in the same manner as the bolt It at the hinge and of the blade.

For maintaining the switch in the closed position under the heavy magnetic forces due to short-circuit currents, there may be provided a latch and releasing mechanism therefor for opening and closing the switch of any suitable type. such as illustrated for example in United States Letters Patent 1,755,083, dated April 15, 1930 and assigned to the assignee of this invention. As illustrated, this .latching mechanism comprises a latch 23 pivotally mounted on the terminal portion III of the contact 6. Secured to the end of the composite blade between the members I! as by bolts 24 is a tongue 25 which rides under a hook on the latch 23 when the switch blade is moved to the closed position. On the rear side or the tongue 2!, as viewed in Fig. I, there is a backing member 26.

In order to release the latch and open and close the switch, the tongue 25 has pivoted thereon at 21 a combination switch-operating and latch-releasing member 28. with an opening or eye 29 for receiving the usual switch hook and also has a cam-operating projection 80 which, on clockwise movement of the member 20, engages a projection II on the latch 21 to disengage the latch from the tongue 25. The bolts 24, which secure the tongue to the channel-shaped members I9, pass through the insulating members I! and help to secure them to the members II. In order to support the electric current-conducting device I! so that it may This is provided bridge the insulated gap between the channelshaped members I4 and I9, I suitably mount on the blade structure two supporting members, such as brackets 32. As shown, each of these brackets is mounted on a T-shaped base or support 33 shown more clearly in Fig. 3. In order to maintain the floating blade," the vertical leg of the T-shaped supporting member 33 is secured at the respective ends to only one 01' the channel-shaped members H and It by suitable means which are shown as rivets.

In accordance with my invention, I so mount the brackets 32 on the supporting members II that the brackets 32 provide minimum resistance to bending about an axis at right angles to the plane of movement 0! the blade in order that, ii there is any give between the parts of the composite blade in the switch-opening and -closing movements thereof, the movement oi the parts will be absorbed to a large extent by the yielding or bending action of the brackets without bending the structure or the device it. This is particularly important in case of ceramic or glass elements or of ceramic coated or encased elements as is common with porcelain-clad resistance units since their frangible nature does not admit of any bending action. Thus I mount the angular-shaped brackets 32 so that the plane of the outstanding leg of the angle is at right angles to the blade structure. Moreover, the brackets 32 are made as thin as possible consistent with the support of the device [3 so that the brackets may yield without distorting the device IS. The brackets 32 may be secured to the supports 33 in any suitable manner as by screws 34. Likewise the device I! may be secured to the upstanding leg of the brackets II by suitable means such as bolts 35. As shown in Fig. 4, other devices such as a fuse ii, for example, may be mounted in use clips 32' suitably secured to the supports 33.

Since it is sometimes desired to limit the movement of the blade in the open position each of the channel-shaped members It may be provided with a downward extension 35. Between these extensions, there is mounted a pin 31 which, in the full-open position oi the switch, bears against the contact 5 which acts as a stop. Also with this stop arrangement, there is no tendency for the blade to swing closed when the switch is horizontally mounted since the center of g avity of the blade is in the open position to the right of the pivot pin it.

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 scope of my invention.

What I claim as new and desire to secure by Letters Patent 01 the United States is:

1. In combination, two spaced stationary switch contacts and a composite blade structure for bridging said contacts comprising two channel-shaped metallic members in pivotal contacting engagement with one of said contacts, two insulating elements respectively having a material length at one end firmly seated against the web and between the flanges of said pivoted channel-shaped members, and two other channel-shaped metallic members against the web and between the flanges of which a material length of the other end portions of said elements are respectively firmly seated, said other members being movable into and out of contacting engagement with the other of said contacts.

2. In combination, two spaced stationary switch contacts, a composite blade structure for bridging said contacts comprising two channelshaped metallic members in pivotal contacting engagement with one of said contacts, two insulating elements respectively having a material length at one end firmly seated against the web and between the flanges of said pivotally mounted channel-shaped members and two other channel-shaped metallic members against the web and between the flanges'of which a material length of the other end portions of said elements are respectively firmly seated, said other members being movable into and out of engagement with the other of said contacts, and two metallic supports respectively mounted on the metallic end portions of said blade structure and having minimum resistance to bending about an axis substantially perpendicular to the plane of movement of said blade structure.

3. In combination, two spaced stationary switch contacts, and a composite blade structure for bridging said contacts comprising twochannel-shaped metallic members pivotally mounted back to back against opposite sides of one of said contacts, two insulating elements respectively having a material length at one end firmly seated against the web and between the flanges of said pivotally mounted channelshaped members and two channel-shaped metallic members against the web and between the flanges of which a material length of the other end portions of said elements are respectively firmly seated with the webs of the members back to back and movable into and out of engagement with the other of said contacts.

4. In combination, two spaced stationary switch contacts, a composite blade structure for bridging said contacts comprising two-channel-shaped metallic members pivotally mounted back to back against opposite sides of one of said contacts, two insulating elements respectively having a material length at one end firmly seated against the web and between the flanges of said pivotally mounted channel-shaped members and two channel-shaped metallic members against the web and between the flanges of which a material length of the other end portions of said elements are respectively firmly seated with the webs of the members back to back and movable into and out of engagement with the other of said contacts, two metallic supports respectively mounted on the metallic end portions of said blade structure and having minimum resistance to bending about an axis substantially perpendicular to the plane of movement of said blade structure, and a frangibly supported electric current-conducting device mounted between said metallic supports.

5. In combination, two spaced stationary switch contacts, a composite blade structure for bridging said contacts comprising two channelshaped metallic members pivotally mounted back to back against opposite sides of one of said contacts, two insulating elements respectively having a material length at one end firmly seated against the web and between the flanges of said pivotally mounted channel-shaped members and two channel-shaped metallic members against the web and between the flanges of which a material length of the other end portions of said elements are respectively firmly seated with the webs of the members back to back and movable into and out of engagement with the other of said contacts, two metallic supports respectively mounted on the metallic end portions of said blade structure and having minimum resistance to bending about an axis substantially perpendicular to the plane of movement of said blade structureand electric current-conducting means mounted between said supports.

6. In combination, two spaced stationary switch contacts, a composite blade structure for bridging said contacts comprising two channelshaped metallic members pivotally mounted back to back against opposite sides of one of said contacts, two insulating elements respectively having a material length at one end firmly seated against the web and between the flanges of said pivotally mounted channel-shaped members and two channel-shaped metallic members against the web and between the flanges of which a material length of the other end portions of said elements are respectively seated with the webs of the members back to back and movable into and out of engagement with the other of said contacts, two angular supports respectively having one leg mounted on the metallic end portions of said blade structure with minimum resistance to bending about an axis substantially perpendicular to the plane of movement of said blade structure, and a frangible element mounted between the outstanding legs of said angular supports.

7. In combination, two spaced stationary switch contacts, a composite blade structure for bridging said contacts comprising two channelshaped metallic members pivotally mounted back to back against opposite sides of one of said contacts, two insulating elements respectively having a material length at one end firmly seated against the web and between the flanges of said pivotally mounted channel-shaped members and two channel-shaped metallic members against the web and between the flanges of which a material length of the other end portions of said elements are respectively seated with the webs of ,the members back to back and movable into and out of engagement with the other of said contacts, two angular supports respectively having one leg mounted on the metallic end portions of said blade structure with minimum resistance to bending about an axis substantially perpendicular to the plane of movement of said blade structure, and a frangibly supported electric current-conducting device mounted between the outstanding legs of said supports.

8. In combination, two spaced stationary switch contacts each having a substantially flat contacting portion, a composite blade structure for bridging said contacts comprising two channel-shaped members of electric current-conducting material pivotally mounted back to back against opposite sides of the contacting portion of one of said contacts, two substantially flat insulating elements respectively having a material length at one end firmly seated against the web and between the flanges of said pivotally mounted channel-shaped members and two channelshaped members of electric current-conducting material against the web and between the flanges of which a material length of the other end portions of said elements are respectively seated and movable into and out of engagement with the contacting portion of the other of said contacts, two brackets of electric current-conducting material respectively mounted on the ing a material length at one end secured to said metallic member and another metallic member secured to a material length 0! the other end of said element and movable into and out or engagement with the other of said contacts, and two metallic supports respectively mounted on the metallic end portions oi! said blade structure and having minimum resistance to bendingabout an axis substantially perpendicular to the plane 10 of movement oi said blade structure.

EDWIN A. WILLIAMS, JR.

Images