US3412351A

US3412351A - Toggle mechanism for a circuit breaker

Info

Publication number: US3412351A
Application number: US545434A
Authority: US
Inventors: George S Harper
Original assignee: Airpax Electronics Inc
Current assignee: Airpax Electronics Inc
Priority date: 1966-04-26
Filing date: 1966-04-26
Publication date: 1968-11-19
Anticipated expiration: 1985-11-19
Also published as: GB1185211A; DE1563997A1

Description

Nov. 19, 1968 5. 5. HARPER 3,412,351

TOGGLE MECHANISM FOR A CIRCUIT BREAKER Filed April 26, 1966 4 Sheets-Sheet 1 INVENT OR 64 64 George 5. Harper OR NEYS Nov. 19, 1968 c. s. HARPER TOGGLE MECHANISM FOR A CIRCUIT BREAKER Filed April 26, 1966 4 Sheets-Sheet 2 9 llllil 6 IN VE NTOR George 5. Harper BY 22%,WM;

ATTORNEYS Nov. 19, 1968 G. s. HARPER 3,412,351

TOGGLE MECHANISM FOR A CIRCUIT BREAKER Filed April 26, 1966 4 Sheets-Sheet 5 FIG. 3.

INVENTOR George .S. Harper ORNEYS Nov. 19, 1968 G. s. HARPER 3,412,351

TOGGLE MECHANISM FOR A CIRCUIT BREAKER Filed April 26, 1966 4 Sheets-Sheet 4 FIG. 4.

INVENT OR Gear 8 .5. Har er FIG. 9. g p

ORNEYS United States Patent ABSTRACT OF THE DISCLOSURE A toggle mechanism for circuit v breakers including first and second pivotally mounted levers which are operatively connected through a pair of pivotal links. Means are provided on the links for locking them against pivotal movement with respect to each other. Further means are provided to unlock the locking means to permit relative pivotal movement to thereby effect the tripping of the mechanism.

This invention relates to a circuit breaker and toggle mechanism therefor and is a continuation-in-part of the circuit-breaker mechanism disclosed in my copending application Ser. No. 377,993 filed June 25, 1964, now Patent 3,251,232, relative to its application to circuit breakers of greater capacity.

It is a further object of this invention to provide a simplified linkage which will withstand the shock and vibration without tripping when subjected to environmental conditions causing violent stresses on the circuit breakers.

These and other objects of the invention will be manifest from the following description and accompanying drawings wherein:

FIG. 1 is a perspective view of the inventive circuit breaker in its housing;

FIG. 2 is a view with one side of housing removed showing the mechanism in relatched open position where the contacts are open;

FIG. 3 is a partial sectional view showing the mechanism in a position where the contacts are closed;

FIG. 4 is a partial sectional view showing the mechanism in an intermediate or tripped open position;

FIG. 5 is a section along the line 55 of FIG. 2;

FIG. 6 is an enlarged section on the line 6-6 of FIG. 2 but showing the threaded holding ferrule in place;

FIG. 7 is an enlarged detail of the sear pin and striker bar assembly;

FIG. 8 is a detail view of the engagement of the sear pin and striker bar assembly in engagement with the forked lever; and

FIG. 9 is a detail of the electromagnet armature bell crank assembly.

In the housing 10, which is formed of a molded plastic of good electrical insulation properties, is supported a frame 11 upon which is mounted the operating elements of the circuit breaker to move the movable contact 12 into and out of engagement with fixed contact 13.

The movable contact is secured to a lever 14 pivotally and slidably mounted on the frame by a pin 15 and an elongated opening 16. Pin 15 is mounted in the frame 11 intermediate the ends while the ends extend beyond the frame and fit snugly into recesses 17 molded in the housing portions and 10' as seen in FIG. 5. A spring 18 is wound around the pin and is provided with a biasing arm 19 bearing against the lever 14 and a reaction arm 20 bearing against the frame 11. Portions of the frame 11 have been omitted from FIGS. 3 and 4 for the sake of clarity. The entire frame 11 is shown in FIG. 2.

An actuating lever 21 is pivotally mounted on the frame 11 by a pin 22. The pin 22 is mounted in the frame intermediate the ends while the ends extendsbeyond the frame and fit snugly into recesses 22 molded in the housing 10 (as seen in FIG. 5). A spring 23 is wound around the pin 22 and has a biasing arm 24 bearing against a pin 25 and a reaction arm 26 bearingagainst the frame 11.

An L-sh'aped link 27 is pivotally mounted on pin 25 and is pivotally connected to a speced pair of links 28 by a pin 29. The links 28 are pivotally connected by a pin 30 to straddle the lever 14.

A shaft of sear pin 31 is rotatably supported in link 27 at the #bend of the L and is provided with a reduced section 32 between the links which results from grinding .a flat surface 32 on shaft 31 (FIG. 7) which acts as a sear for edge 42 of forked member 40. An arm or striker bar 33 is mounted rigidly and nonrotatably on shaft 31 and carries a tab 34 bent up from the end of the arm. The end of shaft 31 is square to accommodate the square hole in arm 33. After assembly, the end of shaft 31 is peened tight against arm 33 thus permanently keying the shaft and arm together. A spring 35 is wound around shaft 31 and is provided with arms 36 arid 37 bearing respectively against a stop 38 integral with, one arm of link 27 and against an extension 39 of arm 33. The spring is wound to urge the extension 39 against the stop 38.

A forked member 40 is pivotally mounted on pin 25 between the parallel arms of link 27. One leg 41 of the fork is provided with an edge portion 42 for engagement with the sear portion 32 of shaft 31, and the other leg 43 of the fork is provided with a curved cam section 44 for engagement with a pin 45 carried by links 28. Between the legs at the end of cam section 44 is a locking recess 46.

The frame 11 is provided with a shelf 47 on which is mounted an electromagnet 48 having a winding, one end of which is connected in series with terminal 49 and the other end in series with a braided, flexible copper wire 50 secured to lever 14, movable contact 12,;fixed contact 13, contact support 51 and terminal 52. Anfarmature 53 is pivotally mounted on the frame by a pin 54 and is integral with an armature lever 55 to forni' therewith a bell crank 56. Spring 57 is mounted on pin 54 to bias the bell crank 56 towards the position shown in FIG. 2. The free end of the armature lever forms an arcuate trigger cam surface 58. In the closed contact position, the linkage is in the position shown in FIG. 3 with the tab portion 34 adjacent the arcuate trigger cam surface 58 at the end of armature lever 55.

On overload the electromagnet 48 is energized to attract armature 53 to pivot armature lever 55 bringing the trigger cam surface 58 into contact with tab 34 to rotate striker bar 33 and shaft 31. Rotation of the shaft 31 presents the reduced section 32 to the edge 42 of the fork 40, allowing the fork 40 to rotate counterclockwise about pin 25 to release pin 45 from recess 46, as illustrated in FIG. 4. The release of pin 45 allows the linkage to collapse and the lever 14 to pivot about pin 15 to separate the

contacts

12 and 13. The are drawn by the separating contacts is extinguished by its reaction to the

arc chutes

59 and 60 in the usual manner. Vent opening 67 is provided in the casing 10 closely adjacent the arc chutes and serving as a pressure release for the gases produced by arcing. The force of spring 23 reacts against pin 25 to rotate the lever 21 to the position shown in FIG. 2. The movement of pin 25 about pin 22, under the urging of spring 23, realigns

links

27 and 28 and fork element 40 to replace pin 45 in recess 46 as shown in FIG. 2. In order to close the contacts, the handle is rotated clockwise about pin 22 to force the linkage down to rotate lever 14. When the contacts close, they become a pivot about which lever 14 is rotated against the force 3 of spring 18 to load the spring and linkage for future toggle action.

The housing is formed of two mirror-image sections 10 and 10 (FIGS. 1 and 5) which are secured together by rivets 62 passing through openings in the housing. One of the sections, such as 10, is provided with 'an elongated groove 70, and the other section is provided with an elongated tongue which is snugly received in the groove. This tongue-and-groove arrangement is for the purpose of accurately aligning the housing sections on assembly.

Each housing section is provided with recesses 63 molded in the meeting faces. The recesses 63 are provided with enlarged hexagon-a1 portions 64. When the sections are secured together as shown in FIG. 5, the recesses 63 combine to provide openings which receive threaded metal ferrules 65 (FIG. 6) with hexagonal heads by which the assembly is secured to a support. Therecesses 66 combine to provide openings for the reception of the threaded

terminals

49 and 52.

What is claimed is; s r Y 1. A circuit breaker comp-rising a housing of molded plastic electrical insulating material, said housing having spaced recesses therein, a frame in said housing, a pair of spaced pins mounted in said frame and extending through the frame and into said recesses, a fixed contact and a movable contact in said housing, a toggle mechanism for moving said movable contact into and out of contact with said fixed contact, said toggle mechanism comprising a first lever pivotally and slidably mounted on said frame and carrying said movable contact, a handle 4 mounted on said'frame and having a portion extending outwardly of said housing, a pair of links pivotally connected to each other and to said contact lever and handle respectively, means for locking said pair of links against pivotal movement with respect to each other, and means for unlocking said means to permit pivotal movement of said pair of linles with respect to each other, said locking means comprising a forked lever pivotally mounted on said frame, a pin carried by oneof said pair of links for reception in the fork of said forked lever, a sear on said frame for holding said forked lever against pivotal movement, said unlocking means including a. solenoid and armature responsive to a predetermined current flow through said solenoid for tripping 'saidsear.

2. A circuit breaker according to claim 1 wherein said forked lever is pivotally connected to said handle.

3; A circuit breaker according to claim 1 wherein said fixed contact is mounted on a substantially U-shaped support, said support having one arm carrying said fixed contact spaced inwardly from said housing.

References Cited UNITED STATES PATENTS 3,056,008 9/1962 Schwartz 33538 3,329,912 7/1967 Brackett 335- 3,329,913 7/1967 Camp 335174 BERNARD A. GILHEANY, Primary Examiner.

H. BROOME, Assistant Examiner.