US3056008A

US3056008A - Circuit breaker

Info

Publication number: US3056008A
Application number: US13000A
Authority: US
Inventors: Norman J Schwartz
Original assignee: Heinemann Electric Co
Current assignee: Heinemann Electric Co
Priority date: 1960-03-07
Filing date: 1960-03-07
Publication date: 1962-09-25
Anticipated expiration: 1979-09-25

Description

N. J. SCHWARTZ CIRCUIT BREAKER Filed March 7, 1960 Sept. 25, 1962 nwemro NORMAN d. SCHWARTZ BY L..

/5 ATTO/IIEV United %tates Patent Ofifice 3,056,008 Patented Sept. 25, 1962 Jersey Filed Mar. 7, 1960, Sel. No. 13,000 2 Claims. (Cl. 200-107) This invention relates to electric circuit breakers and more particularly t improvevd contact supporting structure.

In the manufacture of circuit breakers it is desirable, When designing a new circuit breaker of different current rating, to utilize as many parts of the same design as performed satisfactorily in prior constructions, so that the new circuit breaker will have built into it a certain amount of inherent reliability. However, where the new circuit breaker is of substantially higher rating than the old circuit breaker, usually many or all of the parts of the old circuit breaker have to be redesigned to accommodate the larger current. It is an object of this invention to construct a circuit breaker in a manner to utilize the design of soma components theretofore used.

In one new construction, a circuit breaker of a certain size ampere current rating is desired to be constructed utiliZing the design of certain parts previously utilized for a circuit breaker of one-half this current rating. It has been found that by using plural movable contact arms for each pole of the circuit breaker, that the corresponding parts previously utilized could be successfully utilized for the new circuit breaker. Thus, the design 01 parts which have proved themselves successful can be incorporated into the new breaker and the stock of parts which must be maintained by the manufacturer is reduced.

Heretofore, as illustrated by Wilckens Patent No. 2,360,922, it has been the practice to utilize one biasing means, usually a spring, to separate one movable arm from the stationary contact. In the on position of the contacts, With the mechanism latched, this spring also forces the movable contact against the stationary contact. This one spring could have been made large enough to separate the plural contact arms in the new circuit breaker for instance, by making the yokelike portion wide enough to straddle both movable arms. However, it sometimes happens that due to pitting or metal bead formations upon the contact faces, the plane of contact between the pairs of stationary and movable contacts would not be the same. In such a situation, if one such spring were utilized With all the movable arms pivoted about the saine pintle, all the movable contacts would not be bronght into close ab-utment with each other because the first pair of contacts to abut With each other Would prevent the spring from forcing the other pair into abutment resulting in a preponderance of the current being passed through one of the pairs of contacts, causing overheating of this pair of contacts. Thus, it is another object of this invention to insure abutment of all the contacts in the on position by providing an individual bias on each of the movable contact arms and to resiliently mount the stationary contacts.

The foregoing and other objects of this invention, the principles of this invention, and the best mode in which I have contemplated applying such principles will more fully appear from the following description and accompanying draWings in illustration thereof.

In the draWings,

FIG. 1 is a longitudinal sectional view, partly in elevation, illustrating a circuit breaker incorporating the present invention, in the off position of the contacts;

FIG. 2 is a plan view of the two pole circuit breaker illustrated in FIG. 1, partly cut away;

FIG. 3 is a sectional view similar to the left-hand pop tion of FIG. 1 but showing the contacts in the on position and also showing a spring for biasing a movable contact arm; and

FIG. 4 is a plan view, taken along the line 44 in FIG. 3, of the movable contact arms and the springs therefor.

The invention is embodied in a two pole circuit breaker the poles of which are identical and only one of which is hereinafter described, it being understood that the other is similarly constrncted.

The outer insulating casing 10 is divided into a lower or main portion 11 and an upper or cover portion 12 retained by suitable screws passing through the lower portion 11 and not illustrated. The circuit breaker struc ture housed by the casing 10 includes two stationary contacts 15 secured to stationary resilient arms 14, of U shape, as illustrated in FIG. 1. The stationary arms 14 are spaced from each other by a slot 16, as illustrated in FIG. 2, but are inte gml With the terminal conductor 17. A line conductor may be secured to the terminal conductor 17 and, thns, the contacts 15 are in electrical parallel With each other but in electrical series With the line terminal conductor 17.

The stationary contacts 15 mate with two movable contacts 19 carried by two movable arms 20 which are spaced from each other. The movable arms 20 are each connected by one of two flexible conductors 22 to one end 23 of a conductor 24 forming part of an electromagnet. The conductor 24 is in turn connected at its other key end 27 to a terminal 28 which is also connected to a load conductor. Thus, the movable contacts 19 are also in electrical parallel With each other and in electrical series With the conductor 24 and the terminal 28.

Each of the movable arms 20 is part of the circuit breaker mechanism, generally designated as 30, and each of the arms 20 is providcd With an individual bias aWay from the stationary contacts 15 by individual springs 32 for each of the arms.

The action of the movable contacts on predetermined overload is fully set forth in Patents Nos. 2,360,922 and 2,690,486 and such mcchanisms theref0re do not form a part of this invention but for clarity they may -be briefly described as follows. The movable contact arms 20 are each biased by springs 32 aWay from the stationary contacts 15 to the open position of the contacts. The arms 20 are connected by a pintle 33 to a latching mechanism 34 which is in turn connected to a handle 36. When the handle 36 is rotated counter-clockwise, as viewed in FIG. 1, the latching mechanism 34 and the movable arms 20 all move down and bring the contacts 19 into engagement With the contacts 15 against the bias of the springs 32, the

contacts

15 and 19 assuming the position illustrated in FIG. 3. The arms 20 are pivoted about pintles 37 extending through side supporting plates 38 and slots 39 in the arms 20.

The handles of the two poles of the circuit breaker are joined by a common bar 40 and a bolt 41 which extends through both handles and the common bar 40 and which is secured by a fastener 42 at one end.

The conductor 24 surrounds a tube 44 containing a magnetically permeable core (not illustrated) and takes the place of the coil usually associated -With an electromagnet. The magnetic flux of the conductor 24 attracts the core to the upper end (FIG. 1) of the tube upon overload condition. Also, an Lshaped frame member 46 is about the conductor 24 and the tube 44 is mechanically secured to the frame 46 at the lower portion of the tube -by being soldered to the frame.

Upon the occurrence of an overload, the core inside the tube 44 is attracted toward the upper end of the conductor 24, as viewed in FIG. 1, and the upper end of the armature 48 is attracted toward the conductor 24 to bridge the space between the frame 46 and the pole face 45, thereby closing the magnetic circuit. This attraction of the armature also moves the lower portion of the armature to trip the arm 50 forming part of a U- shaped pintle, so that the latching mechanism 34 is free to collapse under pressure from the springs 32. The collapse of the latching mechanism 34 actuates the trip spring 52 in accordance With the disclosure of Patent No. 2,690,486 so that the tripping of one pole of the circuit breaker is effective t trip the other pole of the circuit breaker.

The arc chute structure 55 is placed in an arc chamber 56 formed in the casing for aiding in extinguishing the arcs that tend to form upon the separation of the contacts.

The latching mechanism comprises a toggle formed by an upper link 61 and a lower link 62. The lower link 62 is disposed between the movable arms 20 and pivoted thereto by the pintle 33.

Each of the springs 32 has coils wound about the stationary pintle 64 and ends anchored upon the stationary pintle 37. Also, each of the springs 32 has intermediate yokelike portions 66 bearing against the inclined surfaces of the movable arms 20 between the

pintles

33 and 37.

Force is transmitted between the handle 36 and the movable arms 20 by the toggle 61, 62 when the toggle is rendered rigid by the engagement of a convex surface (net illustrated) on the U-shaped pintle 50 with a tooth (net illustrated) on the upper link 61. When the pintle 60 is rocked by the armature 48, the tooth is disengaged from the convx surface of the pintle 5(P and the toggle 61, 62 collapses under pressure from the springs 32. Also, the contacts may be separated by rocking the handle 36 which pivots the upper end of the link 61 allowing the springs 32 to move the arms 20.

In closing the circuit breaker, the movable contacts 19 engage the stationary contacts before the throw of the handle 36 -is completed. Even though the stationary contacts 15 are resiliently mounted, due to the resiliency of the U-shaped supporting stationary arm 14-, after they flex a minimum amount, they prevent further movement of the movable contacts 19 and continued applicatien ot force from the handle 36 through the pintle 33 shif-ts the lower ends 69 of the arms 20 (relative to the pintle '37) to the middle of the elongated slots 39 (FIG. 3). At the end of this movement the springs 32 bias the movable contacts 19 against the stationary contacts by pivoting them about the pintle 33 because the links 61 and 62 form a ri gid member.

Upon an overload entrent sufficient to open the circuit breaker, the armature rotates the pintle 50 to release the tooth of the link 61. This removes the restraint upon the arms 20 at the pintles 33 and the ends 69 move down to the lower end of the slots 39 and the springs 32 now move the arms 20 to the opn position of the contacts. Movement of the arms 20 in the opening direction is terminated when the upper rear portions 71, as viewed in FIG. 1, abut a vertical portion of the L-shaped frame 46. In the off position of the contacts, the rear portions 71 are vertically aligned With the center of the pintle 37.

Having described this invention, I claim:

1. In apparatus of the character described plural stationary arms each having a stationary contact, plural movable arms each having a movable contact, au electromagnetic device for simultaneously actuating said plural movable arms, said contacts being connected in electrical parallel With each other and in electrical series with said electromagmetic device, and a linkage mechanism controlled by said electromagnetic device and to which both of said movable arms are pivotally connected, a spring portion for providing an individual bias on each of the movable contacts for urging them into abutment With the stationary contacts, during the latched position of the linkage mechanism, said movable arms and movable contacts being spaced from each other, and said movable arms being pivotal independentl of each other.

2. In apparatus of the character described plural stationary arms each having a stationary contact, plural movable arms each having a movable contact, au elec- .trornagnetic device for simultaneously actuating said plural movable arms, said contacts being connected in electrical parallel with each other and in electrical series With said electromagnetic device, said movable arms and movable contacts being spaced from each other throughout their length, said movable arms being pivotal independently of eachother, a linkage mechanism coutrolled by said electromagnetic device and to which both of said movable arms are pivotally connected, said linkage mechanism being latchable and unlatchable and including a link pivotally connected to said movable arms for spacing the arms from each other, said stationary contacts being spaced from each other on spaced, resilient arms, and separate springs for each of said movable arms for biasing the movable contacts into abutment with the stationary contacts when the linkage mechanism is latched and away from said stationary contacts when the linkage in unlatched, said springs having portions contacting said arms and other portions restrained agaist movement.

References Citer] in the file of this patent