US1988687A

US1988687A - Electric switch

Info

Publication number: US1988687A
Application number: US486856A
Authority: US
Inventors: John G Jackson
Original assignee: Square D Co
Current assignee: Schneider Electric USA Inc
Priority date: 1930-10-06
Filing date: 1930-10-06
Publication date: 1935-01-22
Anticipated expiration: 1952-01-22

Description

J. G. JACKSON 1,988,687

ELECTRIC SWITCH Jan. 22, 1935.

Filed 0ct. 6, 1930 ATTORN EY'S Patented Jan. 22, 1935 ELECTRIC SWITCH John G. Jackson, Detroit, Mich., assignor to Square D Company, Detroit, Mich., a corporation of Michigan Application October 6,1930, Serial No. 486,856

5 Claims.

This invention relates generally to electric switches and refers more particularly to knife or jaw switches.

One of the essential objects of the invention 5 is to provide a switch of this type in which the or arcing.

Another object is to provide a switch in which the ribs constitute the second and final stage of contact and exert a higher pressure against opposite sides of the blade than that exerted by the walls of the cup-shaped recess. I

Another object is to provide a switch in which the jaw plates are provided with spring backers that lie flatagainst the jaw plates and cause the ribs aforesaid to grip firmly and positively the knife bladeor bar so that a better contact between the parts is obtained.

Another object is to simplify, improve generally and render more efiicient switch structures of the type described.

'Other objects, advantages, and novel details of construction of this invention will be made more apparent as this description proceeds, especially when considered in connection with the accompanying drawing wherein:

Figure 1 is an edge elevation of a switch embodying my invention and showing the knife blade about to enter the jaw;

Figure 2 is a. view similar to Figure 1 but showing the parts after the knife blade is in engagement with the jaw;

Figure 3 is a side elevation of the structure illustrated in Figure 1, omitting the knife blade.

Referring now to the drawing, A is a terminal bar of good conducting material such as copper; B is a jaw embodying my invention extending upwardly from. the bar A; and C is a movable knife blade or bar engageable with the jaw B to close an electric circuit. As shown, the terminal bar A is substantially L-shape and has a said plates.

Preferably the

plates

2 and 3 are secured at their lower ends to opposite sides of the upright portion 6 of the terminal bar A and are provided at their upper ends with opposed inwardly projecting transversely extending outwardly opening substantially channel shape em- 5 bossed portions or ribs '7 and 8 respectively and opposed outwardly extending

curved end portions

9 and 10 respectively. As shown in Figure 1, the

ribs

7 and 8, curved

end portions

9 and 10 and intermediate parallel portions 11 and 12 re- 10 spectively of the plates form a cup-shaped recess for the reception of the knife blades C.- The

spring backers

4 and 5 are preferably plates of spring metal that are fiat against the outer faces of the

parallel plates

2 and 3 and extend from 15 the lower ends thereof to points below but adjacent to the

ribs

7 and 8. Preferably rivets 13 extend through the upstanding portion 6 of the terminal bar at spaced points thereof and constitute a common securing means for the

plates

2 and 3 and

spring backers

4 and 5.

In use when the knife blade C is inserted between .the

plates

2 and 3 the

curved end portions

9 and 10 of said plates will guide the knife blade inwardly between the plates. The blade C will first contact with opposite sides of the cup shaped recess and will then be engaged by the ribs '7 and 8. The

spring backers

4 and 5 resist the separation of the

ribs

7 and 8, hence when the

ribs

7 and 8 are separated by the knife blade C, the

backers

4 and 5 are under tension and cause the said ribs to press against and firmly grip the knife blade. In fact, the construction and arrangement of the ribs is such that an extremely fine line contact with opposite sides of the knife blade C is obtained. In Figure 1 it will be noted that the knife blade C is in a plane parallel to the planes in which the

plates

2 and 3 are located, however, the construction and arrangement of the parts is such that if the blade C should not be parallel but should be inclined somewhat relative to the plates when inserted therebetween, the

ribs

7 and 8 will still grip and form line contact with said blade. Moreover, such line contact will be obtained regardless of how far the blade is inserted between the

ribs

7 and 8. Thus a better and more eflicient contact is made for the conveyance of electric current.

Thus from the foregoing it will be readily apparent that I have provided a two stage contact switch wherein the pressure exerted by the side walls of the recess is relatively light while the final contact of the ribswith the blade is comparatively heavy. Similar1y.' when the blade is withdrawn from the ribs into the cup-shaped recess the contact pressure is relieved and when the blade is withdrawn i'rom the recess the circuit is broken.

While I have shown and described a switch comprising separately formed

plates

2 and 3, it is apparent such plates may be integral in the .form of a U or may be integral with the upright portion 6 of the terminal bar A.

What I claim as my invention is:

1. An electric contact anchored at one end and free at the other, said contact being provided between said ends with longitudinally spaced means for successive engagement with a cooperating contact, the means initially engageable by said cooperating contact being capable of carrying the full load until the second means is engaged and comprising substantially parallel portions formed to subject the cooperating contact to a preliminary pressure and hold the same, the means subsequently engageable by saidcooperating contact comprising opposed portions disposed closer together and formed to subject said cooperating contact to a greater pressure and hold the same.

2. An electric contact anchored at one end and free at the other, said contact being provided at its free end with flaring guide means for a cooperating contact and provided between said ends with longitudinally spaced means ior successive engagement with such cooperating contact, the means initially engageable by said cooperating contact being adjacent the flaring guide means and comprising substantially parallel portions formed to subject the cooperating contact to a preliminary pressure and hold the same, and the means subsequently engageable by said cooperating contact being nearer to the anchored end aforesaid and comprising opposed portions disposed closer together and formed to subject such cooperating contact to a greater pressure and hold the same.

3. An electric contact provided with longitudinally spaced means for successive engagement with a cooperating contact, the means initially engageable by said cooperating contact comprising substantially parallel portions constructed and arranged to subject the cooperating contact to a preliminary pressure and hold the same, and the means subsequently engageable by said cooperating contact comprising opposed portions integral with the parallel portions but constructed and arranged to subject the cooperating contact to a greater pressure and hold the same.

4. An electric contact anchored at one end and having flaring guide portions at its other end, said contact being provided between said anchored end and flaring guide portions with longitudinally spaced means for successive engagement with a cooperating contact, the means initially engageable by said cooperating contact comprising opposed portions constructed and arranged to subject the cooperating contact to a preliminary pressure and hold the same, and the means subsequently engageable by the cooperating contactcomprising opposed portions that are closer together-than the opposed portions just mentioned and are formed to subject the cooperating contact to a greater pressure and hold the same.

5. An electric contact having substantially parallel members anchored at one end and provided at the other end with flaring guide portions for a cooperating contact, said members being provided intermediate their anchored ends and flaring guide portions with longitudinally spaced means for successive engagement by such cooperating contact, the means initially engageable by said cooperating contact comprising substantially parallel portions offset inward ly relative to said members, said parallel por-.