US2872659A

US2872659A - Contact assembly

Info

Publication number: US2872659A
Application number: US389245A
Authority: US
Inventors: Ervin E Wills
Original assignee: ELECTRIC PRODUCTS CO
Current assignee: ELECTRIC PRODUCTS CO
Priority date: 1953-10-30
Filing date: 1953-10-30
Publication date: 1959-02-03
Anticipated expiration: 1976-02-03

Description

Feb. 3, 1959 E. E. WILLS cormc'r ASSEMBLY Filed Oct. so, 1953 IN V EN TOR. [7-0177 1'7. }////5 ATTORNEYS CQNTACT ASSEMBLY Ervin E. Wills, Aifton, Mo., assignor to Electric Products Company, a corporation of Delaware Application October so, 1953 Serial No. 389,245 8 Claims. or. 339-255 The present invention relates to switches and more particularly to electric contact assemblies of the plug-in type.

Plug-in contact assemblies of the type generally used, for example and not by way of limitation, in a draw-out switch gear comprise a stationary blade-like contact member and a companion movable plug-in contact member. The movable plug-in contact member comprises a conducting part provided, at one end thereof, with a plurality of pairs of contact fingers which engage the stationary blade contact therebetween. Heretofore, said fingers were fixedly secured to the contact part and were usually spring biased to provide the required contact pressure, the fingers of each pair being urged apart upon their engagement with the stationary blade contact. However, corrosion or the presence of foreign matter at the point of securement for connection of the fingers to the conducting part tended to decrease current fiow through the movable plug-in contact member.

Therefore, the primary object of the present invention is to eliminate the causes of the reduced current flow in plug-in contact members of the prior art.

Another object is the provision of a plug-in contact member wherein the contact fingers are free of fixed s ecurement or connection to their conducting part.

Another object is the provision in a plug-in contact member of means to provide a wiping action between the contact fingers and their conducting part to provide clean contact surfaces.

A further object is the provision of means whereby the aforementioned wiping action may be achieved without necessitating any structural modifications to the stationary blade contact.

A further object is the provision of means in a plug-in contact assembly having a conducting part with a plurality of pairs of contact fingers to cause said fingers to move relative to said conducting part to effect a wipingaction therewith automatically upon engagement with the stationary blade contact and further returning said fingers automatically to their original position during disengagement of said fingers from said stationary blade contact and insuring that said fingers remain in the proper position for subsequent engagement.

The above and other objects, features and advantages of the present invention will be more fully understood from the following description considered in connection with the accompanying illustrative drawings.

In the drawings which illustrate the best mode presently contemplated by me of carrying out my invention:

Fig. 1 is a plan view of a plug-in contact assembly pursuant to the present invention, the companion movable and stationary contact members being illustrated in the disengaged condition thereof;

Fig. 2 is a section taken on line 2-2 of Fig. i;

Fig. 3 is a section similar to that of Fig. 2 but showing the. companion movable and stationary contact members just beginning to make engagement;

Fig. 4 is a section similar to that of Fig. 2 but show:

Patented Feb. 3,

ing the companion movable and stationary contact members engaged to their fullest extent; and

Fig. 5 is an end view of the movable contact member taken in the direction of the arrow of Fig. 2.

Referring now to the drawings, reference numeral 30 designates a stationary blade-like contact member suitably mounted in position and which, as here shown, is formed of any suitable electric conducting material reversely bent upon itself to form an arcuate cam-like edge 12. It will be understood that the stationary bladelike contact 10 could be made solid if desired. The purpose of the curved edge 12 will hereinafter become apparent. A movable contact assembly designated generally at 14 comprises a conducting port or movable contact member 16 which takes the form of a blade-like member which is of approximately the same thickness as the distance between the

outer surfaces

11 and 13 of the contact 16. It will be understood that the contact part in is formed of any suitable electric conducting material and may be carried by a suitable portion 17 of a draw-out switch gear or similar device, being secured thereto as by the securing elements 19. A frame retainer member or mounting member shown generally at 18 is floatingly mounted on the conducting part 16 by a pair of shoulder screws 2 having a threaded portion 21 and a shoulder portion 23. To this end the frame member 318 is provided with two elongated apextures 22 adapted to receive said shoulder screws. The conducting part 16 is provided with tapped holes 24 in alignment with the openings 22 and which receive the threaded portions 21 of the screws 20. interposed between the frame 38 and the conducting member 16 and surrounding the shoulder portions 23 of the screws 2i) in a helical coil spring 26 which normally biases the frame member outwardly with respect to the conducting part 16 as shown most clearly in Figs. 2 and 3. The .frame member 18 is provided with a central portion 23 in which the openings 22 are disposed and two oppositely disposed portions 30 extending outwardly from said central portion in angular relation thereto. The frame member 18 is further provided with a peripherally extending flange 32 for increasing the rigidity of the frame member, which is preferably formed from relatively thin sheet metal. Each of the angular portions 3% of the frame 18 have therein a pair of notches or cut-out 1nount ing portions 34 and extending through each of said notches is a pair of contact fingers or bridging contacts referred to generally at 36. The contact fingers each have a forward inclined edge 33, a front contact portion 41 and a rear contact portion 42. The contact fingers are each further provided with a notch 54 disposed in one surface thereof which seats on the edges of the notches 34 in frame member 18 as best shown in Figs. 2, 3 and 4. On the opposite elongated surfaces of the contact fingers there is provided a pair of notches 46 and 48 which serve to position flat leaf spring 5% which is provided for each pair of contact fingers and which urges said contact fingers in the direction of conducting part 16.

The operation of my contact assembly will now be described. When the stationary contact 10 and the movable conducting part 16 are disengaged for opening the switch,

assembly 14 is moved in the direction depicted by the arrow in Fig. 2 the inclined forward portions 38 of the contact fingers engage stationary contact in the manner shown in Fig. 3. Further movement in the direction of the arrow will cause the front contact portions 40 to ride or cam over the curved or companion portion 12 of stationary contact 10. When this occurs it will be obvious that said contact fingers will be spread apart against the action of springs 50, the point of contact between the rear contact portion 42 and the conducting part 16 acting as a fulcrum for the outward pivotal movement that occurs. Since the flat springs 50 are relatively strong as compared to the helical coil springs 26, the clamping action effected by the front contact portions on the parallel

outer surfaces

11 and 13 of stationary contact 1v) is sutficient to maintain said contact fingers momentarily stationary relative to contact 10 even though the conducting part 16 is still moving in the direction of the arrow. Thus a relative movement between contact fingers 36 and the conducting part 16 is achieved which results in a wiping action between the rear contact portions 42 and said conducting part, it being obvious that during said relative movement spring 26 is being compressed. Said relative movement will terminate when flange 32 of mernber 18 engages the confronting end of conducting part 16 as shown clearly in Fig. 4. At this time the contact fingers 36 and conducting part 16 again begin to move as a unit during which movement front contact portions 46 make a wiping engagement with

surfaces

11 and 13 of stationary contact 10. This movement will terminate when the movable contact assembly 14 has moved inwardly to the point where the head of screws abuts the outer edge of contact 10 as shown in Fig. 4. To disengage the movable contact assembly from the stationary contact blade thereby breaking the circuit, it is simply necessary to move the contact assembly 14 in the opposite direction to that indicated by the arrows of Figs. 2 and 3 until the assembly again resumes the position 'of first Fig. 3 and then Fig. 2. When the conducting part 16 is moved in its disengaging direction from the position shown in Fig. 4, the clamping action between front contact portions 40 and the stationary contact 10 will again cause the contact fingers to remain fixed until the heads of the shoulder screws 20, which, of course, are moving with conducting part 16 to which they are secured, engage the central portion 28 of the frame member 18. When this occurs the contact fingers will resume movement with conducting part 16 as a unit until complete disengagement occurs. After the contacts are completely disengaged, spring 26 will serve to maintain the contact fingers 36 in their forwardly disposed position relative to conducting part 16 whereby to insure that said fingers will he properly positioned for subsequent engagement with stationary contact 10.

Since it is important that the contact fingers be properly aligned with respect to the stationary blade contact 10, the mounting openings 22 for frame member 18 are made elongated. By this construction said frame member can be laterally shifted with respect to conducting part 16 until proper alignment of said contact fingers with said stationary blade contact 10 is attained.

The present invention is related to the subject matter of my United States patent application Serial No. 336,515, filed February 12, 1953, assigned to the assignee of the present application.

It will be obvious that while four pairs of contact fingers have been illustrated as being carried by conducting part 16, any number of pairs of contacts may be employed. Also, if desired, the various pairs of contact fingers can be staggered in the manner indicated in said application, Serial No. 336,515, in order to reduce the force required to move the movable contact assembly into engagement with the fixed blade contact.

While I have shown and described the preferred embodiments of my invention, it will be understood that various changes may be made in the ideas or principles of the invention within the scope of the appended claims.

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

1. A contact assembly comprising a pair of relatively movable contact members, a frame member carried by one of said contact members and having parts thereof extending therefrom at the opposite sides, respectively of said one contact member, said parts each being provided with a plurality of spaced mounting portions with said portions in each part in registry with associated portions, respectively, in the other part, a bridging contact mounted in each mounting portion so that the bridging contacts in each pair of associated portions in said parts are in alignment, said bridging contacts projecting forwardly of said one contact member, and spring means provided in said mounting portions, respectively, for biasing the aligned bridging contacts toward each other.

2. A contact assembly comprising a pair of relatively movable contact members, a frame member carried by one of said contact members and having parts thereof extending therefrom at the opposite Sides, respectively of said one contact member, said parts each being provided with a plurality of spaced mounting portions with said portions in each part in registry with associated portions respectively, in the other part, a bridging contact mounted in each mounting portion so that the bridging contacts in each pair of associated portions in said parts are in alignment, said bridging contacts projecting forwardly of said one contact member, and spring means provided in said mounting portions, respectively for biasing the aligned bridging contacts toward each other, said spring means being constituted by leaf springs and each leaf spring extending longitudinally of its associated bridging contact.

3. A contact assembly comprising a stationary contact member and a companion movable contact member, a frame member mounted by said movable contact member and having parts thereof extending therefrom at opposite sides, respectively, of said movable contact member, a bridging contact mounted in each of saidparts and extending forwardly of said movable contact member, said bridging contacts each being recessed in a portion thereof which confronts said movable contact, and said frame parts being engaged in the recesses of the bridging contacts mounted thereby for preventing relative longitudinal displacement of said bridging contacts, said frame member mounting a leaf spring for each of said bridging contacts, and said leaf springs engaging their associated bridging contacts in portions of the latter opposite the recessed portions thereof for biasing said bridging contacts toward each other.

4. A contact assembly for engaging a companion conducting member, said assembly including a plurality of elongated bridging contacts, a contact member carrying saidbridging contacts, said contact member having an end and having lateral surfaces adjoining said end, each of said bridging contacts being in wiping engagement with a lateral surface of said contact member, said end of said contact member being flanked by said bridging contacts, the bridging contacts projecting beyond said end for engagement with the companion conducting member, a retainer having interlocking engagement with said bridging contacts for retaining them against shifting longitudinally in relation to each other, said retainer having a portion disposed between said bridging contacts opposite said end of said contact member, and a lost-motion connecting element extending from said end of said contact member loosely through said'retainer portion to the opposite side thereof and having an enlargement at said opposite side of said retainer portion, said enlargement being spaced from said end of said contact member by a distance greater than the thickness of said retainer portion for providing limited movement of the said bridging contacts as a unit with said retainer in relation to said contact member.

5. A contact assembly for engaging a companion conducting member, said assembly including a plurality of elongated bridging contacts, a contact member carrying said bridging contacts, said contact member having an end and having lateral surfaces adjoining said end, each of said bridging contacts being in wiping engagement with a lateral surface of said contact member, said end of said contact member being flanked by said bridging contacts, the bridging contacts projecting beyond said end for engagement with the companion conducting member, a retainer having interlocking engagement with said bridging contacts for retaining them against shifting longitudinally in relation to each other, said retainer having a portion disposed between said bridging contacts opposite said end of said contact member, a lost-motion connecting element extending from said end of said contact member loosely through said retainer portion to the opposite side thereof and having an enlargement at said opposite side of said retainer portion, said enlargement being spaced from said end of said contact member by a distance greater than the thickness of said retainer portion for providing limited longitudinal movement of said bridging contacts as a unit with said retainer in relation to said contact member, and spring biasing means establishing a normal position of said retainer at one end of the motion afforded by said lost-motion connecting element when the contact assembly is separated from the companion conducting member.

6. A contact assembly for engaging a companion conducting member, saidassembly including a plurality of elongated bridging contacts, a contact member carrying said bridging contacts, said contact member having an end and having lateral surfaces adjoining said end, each of said bridging contacts being in wiping engagement with a lateral surface of said contact member, said end of said contact member being flanked by said bridging contacts, the bridging contacts projecting beyond said end for engagement with the companion conducting member, a retainer having a portion in interlocking engagement with said bridging contacts for retaining them against shifting longitudinally in relation to each other, and said retainer having slots receiving said bridging contacts for retaining them in predetermined spaced relation, said retainer portion being disposed between said bridging contacts opposite said end of said contact member, and a lostmotion connecting element extending from said end of said contact member loosely through a transversely enlarged passage in said retainer portion to the opposite side thereof and having an enlargement at said opposite side of said retainer portion, said enlargement being spaced from said end of said contact member by a distance greater than the thickness of said retainer portion, said lost-motion connecting element thereby providing for limited movement of the said bridging contacts as a unit with said retainer both longitudinally and transversely of said contact member.

7. A contact assembly for engaging a companion conducting member, said assembly including a plurality of elongated bridging contacts, a contact member carrying said bridging contacts, said contact member having an end and having lateral surfaces adjoining said end, each of said bridging contacts being in wiping engagement with a lateral surface of said contact member, said end of said contact member being flanked by said bridging contacts, the bridging contacts projecting beyond said end for engagement with the companion conducting memher, a retainer having a portion in interlocking engagement with said bridging contacts for retaining them against shifting longitudinally in relation to each other, and said retainer having slots receiving said bridging contacts for retaining them in predetermined spaced relation, said retainer portion being disposed between said bridging contacts opposite said end of said contact member, a lost-motion connecting element extending from said end of said contact member loosely through a transversely enlarged passage in said retainer portion to the opposite side thereof and having an enlargement at said opposite side of said retainer portion, said enlargement being spaced from said end of said contact member by a distance greater than the thickness of said retainer portion, said lost-motion connecting element thereby providing for limited movement of said bridging contacts as a unit with said retainer both longitudinally and transversely of said contact member, and spring means biasing said retainer and the bridging contacts as a unit toward the companion conducting member to establish a normal configuration of the lost-motion connection prior to engagement of the bridging contacts with the companion conducting member.

8. A contact assembly for engaging a companion con ducting member, said assembly including a plurality of elongated bridging contacts, a contact member carrying said bridging contacts, said contact member having an end and having lateral surfaces adjoining said end, each of said bridging contacts being in wiping engagement with a lateral surface of said contact member, said end of said contact member being flanked by said bridging contacts, the bridging contacts projecting beyond said end for engagement with the companion conducting memher, a retainer having a portion in interlocking engagement with said bridging contacts for retaining them against shifting longitudinally in relation to each other, said retainer having slots receiving said bridging contacts for retaining them in predetermined spaced relation, said retainer portion being disposed between said bridging contacts opposite said end of said contact member, and a pair of laterally spaced lost-motion connecting elements extending from said end of said contact member at one side of said retainer portion loosely through slots in said retainer portion to the opposite side thereof, the slots being elongated in the direction transverse to a line through the pair of lost-motion connecting elements, and each said connecting element having an enlargement at said opposite side of said retainer portion, each said enlargement being spaced from said end of said contact member by a distance greater than the thickness of said retainer portion, said lost motion connecting elements thereby providing limited movement of said bridging contacts as a unit with said retainer both longitudinally of and in one direction transversely of said contact member.

References Cited in the file of this patent UNITED STATES PATENTS 2,243,567 Linde May 27, 1941 2,265,006 Rubel Dec. 2, 1941 2,300,893 Hayford Nov. 3, 1942. 2,376,818 Rubel May 22, 1945 2,386,611 Ileman Oct. 9, 1945