US3869192A

US3869192A - Circuit breaker with pre-loaded terminal connectors

Info

Publication number: US3869192A
Application number: US364453A
Authority: US
Inventors: Alfred E Maier; James O Rexroad
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1973-05-29
Filing date: 1973-05-29
Publication date: 1975-03-04
Anticipated expiration: 1992-03-04
Also published as: CA999907A; AU6867974A

Abstract

An electrical control device characterized by a drawout circuit breaker and spaced electrical stabs. The circuit breaker includes quick-detachable terminal connectors comprising a pair of oppositely disposed flexible stab contacts engageable with opposite sides of a stab and a spacer between the stab contacts for holding the stab contacts in spaced pre-loaded positions by a distance less than the thickness of the stab, whereby engagement of the stab contacts with the stab provides tight electrical contact therebetween.

Description

, United States Patent [191 Maier et a1.

[451 Mar. 4, 1975 CIRCUIT BREAKER WITH PRE-LOADED TERMINAL CONNECTORS [75] Inventors: Alfred E. Maier, Beaver Falls;

James O. Rexroad, Beaver, both of [73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

' [22] Filed: May 29,1973 t [21] App]. No.: 364,453

[52] US. Cl 339/147, 339/64, 200/50 AA,v

, 339/258 R [51] Int. Cl r; H0lr 3/00 [58] Field of Search 339/19, 147, 258, 222,

339/64; 206/257, 258, 288, 50 AA, 48 KB [56] References Cited' UNlTED STATES PATENTS 3,015,083 12/1961 Juris 339/258 P X 3,274,532 Engel 339/258 P 9/1966 3,343,042 9/1967 Cellerini et a1. ZOO/50 AA 3,744,001 7/1973 Schor 339/14 R Primary Examiner-Roy D. Frazier Assistant E.\'aminerRobert A. Hafer Attorney, Agent, or Firm-L. P. Johns [57] ABSTRACT An electrical control device characterized by a drawout circuit breaker and spaced electrical stabs. The circuit breaker includes quick-detachable terminal connectors comprising a pair of oppositely disposed flexible stab contacts engageable with opposite sides of a stab and a spacer between the stab contacts for holding the stab contacts in spaced pre-loaded positions by a distance less than the thickness of the stab, whereby engagement of the stab contacts with the stab provides tight electrical contact therebetween.

6 Claims, 3 Drawing Figures CIRCUIT BREAKER WITH. PRE-LOADED TERMINAL CONNECTORS BACKGROUND OF THE INVENTION 1. Fiel'dofthe Invention: I

This inventionrelates to detachable terminal connectorsfor a circuitbreaker and more particularly to flexible contacts for engagement with corresponding stabs.

2. Description of the Prior Art:

Generally, circuit breakers of the drawout type are provided with spring contact fingers'that require only a small amount of movement to obtain full engagement with electrical stabs that are aligned with the fingers. Where a large number of spring contact fingers and stabs for engagement therewith are involved, a considerable amount of work is required for complete engagement. Accordingly,.there is a need for a more suitable means for obtaining a good electrical contact between the spring contact fingers and the stabs without reducing the force of engagement between the fingers and the stabs when they are fully engaged.

SUMMARY OF THE INVENTION In accordance with this invention it has been found that the foregoing problem may be overcome by providing a circuit breaker having quick-detachable terminal connectors, each connector comprising a pair of oppositely disposed flexible conductors engageable ducing the force of contact between the fingers and the stabs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view breaker of the drawout type;

- FIG. 2 is a, plan view of pre-loaded spring fingers or terminal conductors taken on the line IIII of FIG, 1 and FIG. 3 is a plan view of one set of spring-fingers in through a circuit contact with a stab.

DESCRIPTION'OF THE PREFERRED I EMBODIMENT In FIG. 1 a circuit breaker is generally indicated at 11 and is generally similar in construction and operation to that disclosed in US. Pat. No. 3,343,042 for which reason an abbreviated description is set forth herein.

Briefly, the circuit breaker 11 comprises a housing 13 and a three-pole circuit breaker mechanism 19 supported within the housing. The housing 13 includes a base 15 and a cover 17 both of which are composed of molded insulating material.

' The circuit breaker mechanism 19 comprises an operating mechanism 21 which includes a pair of toggle links 23 and 25, a switch arm 27, a contact 28, a movable contact 29, a stationary contact 31., and a handle 33. As shown in FIG. 1 the handle 33 is in the OFF position with the

contact

29 and 31 separated in the open each pole unit of the circuit breaker extends from the terminal connector 39, the terminal 37, the conductor 35, the

contacts

31 and 29, the contact arm 28, a flexible conductor 45, a conductor 47, a terminal 49, and a terminal connector 51.

As shown more particularly in FIG. 2 each terminal 37 comprises a plurality of horizontal members extending from the conductor 35. Moreover, the

terminal connectors

39 and 51 of which the terminal connectors 39 are shown in FIG.'2, comprise a pair of clip-on type or quick-detachable contacts which are connected by suitable means, such as nut and bolt assemblies 53, to and between the outer end portions of the members of the terminals 37. Each terminal connector 39 comprises two outer contacts or fingers 55 and two inner contacts or fingers 57, which contacts or fingers are elongated electrical conducting members composed of a flexible material such as sheet metal. As shown in FIG. 1 each terminal connector 39 is split to provide eight separate pairs of contacts or fingers. In FIG. 2 each outer pair of contacts 55 is bent over at the outer end thereof to provide a generally rounded end portion forming a contact surface 59. Likewise, the inner pairs of contacts 57 are provided with rounded end portions forming contact surfaces 61.

In accordance with this invention the terminal connectors 39 comprise the

contacts

55, 57 as well as the spacer 63 between each pair of oppositely disposed

contacts

55 and 57. Each pair of

contacts

55 and 57 are flared outwardly from their base positions on both sides of the spacer 63. In'the position shown in FIG. 2, the contacts 55 and'57 are maintained in stressed positions so that both sides press against opposite sides of the spacer 63. In fact, there may be enough stress on the

flexible contacts

55 and 57 to cause them to come together if the spacer 63 were eliminated. Suffice it to say, in'the positions shown in FIG. 2 the

contacts

55 and 57 are spaced from each other by distances slightly less'than the thickness of stabs and 67 which extend through and are mounted in a support wall 69. Accordingly, when the circuit breaker 11 moves to the right, as'viewed in'FlG. 2, the opposite pairs of

contact surfaces

59 and 61 are in tight surface-to-surface electrical contact with the stabs 65 and 67-and, inasmuch as the stabs are thicker than the spacing between said surfaces before insertion of the stabs, the

contacts

55 and 57 are moved away from opposite sides of the spacer 63. It is noted that the prestressing of the

contacts

55 and 57 by the spacer 63 does not diminish the final force of the contacts on the surfaces of the

stabs

65 and 67.

Another aspect of this invention is the provision of a spacer mounting portion or neck 71 between the base portion 6312 the spacer head portion 63a. The neck 71 is flexible in order to yield in response to pressure from either side of the spacer. Such pressure occurs when the spacing between the center lines of a pair of

stabs

65 and 67 is greater or less than the center lines between an adjacent pair of spacers 63. As shown in FIG. 3 a center line 73 for the terminal connector 39 which extends through the spacer 63 is out of alignment with -a center line 75 of the stab 65 for some reason, such as improper spacing between the

stabs

65 and 67 or between phases. Accordingly, when the terminal connector 39 moves intoengagement with the connector the upper side of the stab 65 moves into engagement with the

contact surfaces

59 and 61 and thereby raises the

contacts

55 and 57 away from the upper side of the spacer 63a. In response to the elimination of pressure from that side of the spacer,*the

contacts

55 and 57 small amount of lateral movement of the fingers is nee-- essary when the drawout circuit breaker is moved into engagement-with the stabsfThe contact force between the fingers and the stabs remain the same as though no spacer were provided and reduces the work required to move the circuit breaker into place. Finally, by providing a spacer with a flexible neck or mounting portion the entire assembly of the fingers on opposite sides of the stab may move into complete electrical contact with any stab which is out of proper alignment.

What is claimed is:

l. A circuit breaker for use 'in drawout switchgear having spaced line stabs and including a circuit breaker and a stationary housing having stationary terminals, the stationary terminals being movableinto and out of contact with the line stabs, the circuit breaker comprising a pair of separable contacts, means for moving the contacts between open and closed positions, first conductor means for connecting one of the contacts to one of the stationary terminals, second conductor means for connecting the other contact to the other terminal, each stationary terminal comprising a quick detachable terminal connector, each connector including a pair of oppositely disposed flexible terminal contacts engageable with opposite sides of a line stab, said oppositely disposed terminal contacts being spaced. from each other by a distance less than the thickness of a line stab when out of contact with said stab, and a spacer between each pair of said terminal contacts, said spacer being flexibly mounted to yield in response to pressure from either side of the spacer.

2. The circuit breaker of claim 1, in which the terminal connectors are elongated members having corresponding end portions fixedly mounted and having other end portions adapted to receive a terminal.

3. The circuit breaker of claim 2, in'which the terminal contacts comprise at least two'members disposed on opposite sides of the spacer and retained by the 1 spacer in spaced tension.

4. The circuit-breaker of claim 3, in which the terminal contacts comprise a pair of flexible members on opposite sides of the spacer, the pair of members on each side comprising a longer outer terminal contact and a shorter inner terminal contact.

5. The circuit breaker of claim 4, in which the end other side. is removed.

Claims

1. A circuit breaker for use in drawout switchgear having spaced line stabs and including a circuit breaker and a stationary housing having stationary terminals, the stationary terminals being movable into and out of contact with the line stabs, the circuit breaker comprising a pair of separable contacts, means for moving the contacts between open and closed positions, first conductor means for connecting one of the contacts to one of the stationary terminals, second conductor means for connecting the other contact to the other terminal, each stationary terminal comprising a quick detachable terminal connector, each connector including a pair of oppositely disposed flexible terminal contacts engageable with opposite sides of a line stab, said oppositely disposed terminal contacts being spaced from each other by a distance less than the thickness of a line stab when out of contact with said stab, and a spacer between each pair of said terminal contacts, said space being flexibly mounted to yield in response to pressure from either side of the spacer.

3. The circuit breaker of claim 2, in which the terminal contacts comprise at least two members disposed on opposite sides of the spacer and retained by the spacer in spaced tension.

4. The circuit breaker of claim 3, in which the terminal contacts comprise a pair of flexible members on opposite sides of the spacer, the pair of members on each side comprising a longer outer terminal contact and a shorter inner terminal contact.

5. The circuit breaker of claim 4, in which the end portions of the terminal contacts are turned inwardly and outwardly for surface contact with the terminals.

6. The circuit breaker of claim 2, in which the spacer is an elongated element having one end portion seated between the fixedly mounted end portions of the elongated members, the element having another end portion between the pair of oppositely disposed flexible portions of the terminal contacts, and the element having a flexible intermediate portion which is deflectable in response to pressure from the terminal contacts on one side when pressure of the terminal contacts on the other side is removed.