US1891070A - Electric circuit breaker - Google Patents

Description

1932- H. TRENCHAM ET AL 1,391,070

ELECTRIC CIRCUIT BREAKER Filed April 30, 1931 2 Sheets-Sheet l L A? J I Ii i F .I. I XI 2 I f 21 T7 3} L"'y Inventors: Henna Trencham, Herbert C. Heath, by m Their Attorne Dec. 13, 1932.

H. TRENCHAM ETAL 1, ,070

ELECTRIC CIRCUIT BREAKER Filed April 30, 1951 2 Sheets-Sheet 2 IIIIIIIIIIIIIIIIIIIIIIIIII 1 Inventors: Henrg Trencham, Herbert C. Heath,

Patented Dec. 13, 1932" UNITED STATES PATENT OFFICE HENRY TRENCHAM, OF R'UISLIP, AND HERBERT C. HEATH, OF WEMBLEY, ENGLAND, ASSIGNORS T0 GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRIC CIRCUIT BREAKER Application filed April 30, 1931, Serial -No. 534,662, and in Great Britain Kay 13, 1880.

Our invention relates to electric circuit breakers, more particularly to mechanism for effecting the tripping operationof circuit mechanism causing opening movement 0 the circuit breaker. However, under certain opcrating conditions, as where the circuit must be cleared within a very short time, it may be desirable to introduce a direct acting trip so as to decrease the time of the tripping opera tion.

In accordance with the present invention,

' in a circuit breaker or a combination circuit breaker andfuse capable of being tripped open by the collapse of an operating toggle mechanism the tripping impulse is transmitted directly to the toggle mechanism through the movable switch member serving to connect the stationary contacts of the switch in the closed circuit position, thereby simplifying the tripping mechanism and eliminating unnecessary tripping linkages.

In carrying the invention into effect, one of the so-called fixed or stationary contacts of the switch is mounted so as to have a limited degree of movement so that the tripping operation is accompanied by an initial movement in the circuit closing direction of the movable switch member coacting with the aforesaid contact, this initial and concurrent m-ovement causing collapse of the toggle mechanism and consequent opening movement of the breaker. The portion of the toggle mechanism operatively connected to the movable switch member for actuating the same into engagement with the stationary contact is preferably arranged to continue its circuit closing movement after the switch H member has engaged the stationary contact and come to rest, this continued movement caus ng compression of a spring further biasing the switch member into engagement with the stationary contact and thereby causing the aforesaid initial movement of the switch member when a tripping device controlling the movement of the stationary contact is actuated.

The control of the limited movement of the stationary contact may be effected by a current responsive device as a'fusible element connected in series with theswitch contacts or by means of an electromagnetic current responsive device. For the purpose of relieving the fusible element, when such is employed, of the tension necessary to maintain the stationary contact in position against the bias of the spring above referred to, there is preferably provided a toggle having one of its links pivoted to the stationary contact and another to a fixed point, the fusible element 35' passing over the common pivot of the two links of the toggle thereby restraining collapse of the toggle. In the case where an electromagnetically controlled tripping device is used to restrain the movement of the stationary contact a toggle may also conveniently be employed the toggle being slightly overset in the closed position of the switch, and collapse thereof is caused by actuation of the tripping device whereby limited movement of the stationary contact takes place with consequent tripping of the toggle mechanism by the tripping impulse transmitted directly by the switch member. The movable switch member may be pivotally connected at one end to one of the stationary contacts having no limited movement or may take the form of a bridging member pivotally attached at its central portlon to an 0 rating rod for making and breaking the circuit at the stationary contacts in a well known manner.

Our invention will be more fully set forth in the following description referring to the accompanying drawings, and the features of novelty whichcharacterize our invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawings, Fig. 1 is an elevational view, partly in section, of a cirthe tripping arrangement illustrated in Fig. 1

1; Fig. 3 is a view of the circuit breaker shown in Fig. 1 in the open circuit position thereof; Fig. 4 is an elevational View, partly in section, of a modified form of trip )ing mechanism in the closed circuit position ,Fig

5 is a similar view showing the apparatus in v the open circuit position, and Fig. 6 is a view similar to Figs. 4 and 5 showin a modification of the movable switch mem er.

Referring to the arrangement shown in Figs. 1 to 3, there is illustrated an oil circuit breaker comprising a stationary contact 10 and a conducting element 11 carried at the lower ends of the insulating bushings 12 and 13 respectively which extend through and are supported in the housing 15 of the circuit breaker. The members 10 and 11 in closed circuit position are electrically connected by the movable switch member 16 carrying the movable contact coacting with contact 10 and in the present instance pivoted at one end to the conducting element 11 and operatively connected through the insulating operating rod 17 to the operating mechanism likewise mounted within the housing 15. The operating mechanism comprises a bellcrank lever 18, to one arm of which the rod 17 is connected, pivotally mounted at 19 with respect to the housing 15 and biased in a counterclockwise direction by the opening spring 20 which is connected at one end to the housing as at 21 and at the other end to an arm of the bellcrank as at 22.

Movement of the bellcrank lever to cause opening and closing of the circuit breaker is e ected throu h a toggle mechanism comprising the lindrs 23, 24 and 25. The link 23 is pivotally connected, as at 26, to the arm 22 of the bellerank 18 and to the link 24 at the point 27. The link 25 is in turn pivotally mounted at 28 on the housing 15 and at its other end is pivotally connected at 29 to the link 24. For the purpose of manually operating the circuit breaker the link 25 is provided with 'a suitable operatin lever 30 mounted externally of the switc housin For the purpose of maintaining the tog e 23-2425 in a slightly overset position %or restraining the switch member in the closed circuit position the link 24 is provided with a pin 31 arranged to be engaged by the overhanging end 32 of the link 23.

The insulating rod 17 is suitably attached at its lower end to the movable switch member 16 and is resiliently connected at its upper end to the bellcrank 18. The up er extension 17 of the rod 17 extends thro g 1 an opening in the pin 32, carried by the be lcrank 18 and is provided at its upper end with a collar or shoulder 33 between which and the pin 32 a spring 34 is positioned so that the rod 17 has both sliding and pivotal movement with respect to the bellcrank 18.

The insulating rod 17 likewise is provided with an abutment 35 which, when the rod 17 is moved upwardly under the influence of spring 34, as will be hereinafter described, enga es an extension 36 of the link 24 cansing t e toggle comprising the links 23 and 24 to collapse.

The tripping device controlli limited movement of the contact 10 is iflustrated more clearly in Fig. 2 wherein the contact 10 is shown pivotally mounted at 37 on a collar 38 carried by an extension of the insulating bushing 12. Mounted also upon the collar 38 is a to gle comprising links 39 and 40, the link 40% hanging en 41 of contact 10 and the link 39 being plvotally connected at 42 to the collar 38, thetwo links having a common pivotal connection 43. As illustrated in Fig. 2, the toggle is shown in the closed circuit position, the tripped or open eircuit position being illustrated by dotted lines. The contact 10 is maintained in the position shown in Fig. 1 by a fusible element or link 44 connected at 45 to-the corresponding conductor stud of the circuit: breaker. the link passing over the common pivot 43 of the toggle and attached at 46 to t .0 contact 10.

The operation of the circuit breaker is as follows: In the closed circuit position illustrated in Fig. 1 the springs 20 and 34 are both under tension, the spring 20 tending to cause the bellcrank 18 to move in a counterclockwise direction to lower the rod 17 to open circuit position, whereas the spring 34 tends to move the rod 17 in, an upward or circuit closing direction. This later movement however is restrained by the toggle 39-40 and the fusible element 44 which is placed under tension and prevents collapse of the tripping toggle. In res onse to a predetermined or abnormal circuit condition, as overload, the current flowing through the fusible element 44 in series with the breaker contacts causes the fusible element to blow so that rupture thereof permits the toggle 39-46 to collapse to the dotted line position under the influence of the spring 34. The initial movement of the switch member 16 in a clockwise direction thus instituted moves,the abutment 35 sharply into engagement with the extension 36 of the toggle link 24 causing collapse of the toggle and consequent opening movement of the breaker under the influence of the opening spring 20 to the position illustrated in Fig. 3.

The closing operation of the circuit breaker must be preceded by replacement of the fusible element. whereupon the toggle 2324 may be straightened by rotating the operating handle 30 in a counterclockwise direction and then moving it in a clockwise direction to rotate the bellcrank member 18 clockwise. During this movement the switch member 16 engages the contact 10 so that subsequent movement of the bellcrank causes only comin pivotally connected to the overspring 34.

Referring now to Figs. 4 and 5, the arrangement shown is generally similar to that shown in Figs. 1 and 2, and does not require detailed description except insofar as the tripping mechanism is concerned. In this case, the tripping device is controlled electromagnetically instead of by a fusible element,

,as in Figs. 1 and 2. The contact 10 is pivotally mounted on the member 47 carried by the insulating member 48 at the lower end of the bushing 12. The member 48 furthermore carries a magnet 49 having a coil 50 and an armature 51 of bellcrank shape, pivoted at 52 to the member 47. The coil 50 is included in series with the switch contacts in the circuit controlled by the breaker. The counterclockwise rotation of the contact 10 about its pivot is restrained by the toggle comprising links 52 and 53 which. in the closed position of the circuit breaker, are slightly overset, shown. ()n a predetermined overload occurring in the circuit, armature 51 is attracted to the magnet 49, and the arm 54 of the armature 51 strikes the common pivot of the links 52 and 53, causing the collapse of the toggle and the opening of the breakerinthe manner described in connection with Figs. 1 and 2 The position of the various parts of the circuit breaker in the tripped-open position are as shown in Fig. 5. On the opening of the circuitbreaker, the armature 51 is no longer attracted, thereby permitting the contact 10 to rotate in a clockwise direction under the action of gravity so that the toggle comprising links 52 and 53 becomes straightened, as shown iuFig. 5.

In Fig. '6 there is shown an arrangement having an electromagnetically operated tripping device similar to that described in connection with Figs. 4 and 5. The only difference in this particular construction is that instead of the switch member 16 being pivoted to the member 11, it is pivotally arranged upon the insulating rod 17. In this case, upon the tripping open of the circuit breaker by the limited movement of contact 10, the switch member 16 is permitted to slide on the contact surfaces of the contact 10 and member 11 about its fulcrum on the insulating rod 17 to the position shown in dotted lines in Fig.

6, whereupon the breaker is tripped open as described in connection with Figs. 4 and Preferably. the switch member 16 is arranged been shown as comprising upper and lower metallic members attached through an insulater which may be of porcelain or any other suitable material. It is to be understood, however, that any: other construction of the insulating rod 17 is permissible provided the switch member is insulated from the toggle operating mechanism. The various links of the toggle operating mechanism usually comprise a pair of parallel members suitably spaced from one another, spacing members serving to provide the necessary pivot points about which the various links co-act.

It is also to be understood that the invention has been described only in connection with a single phase breaker, but the invention may be employed in connection with polyphase circuits. In this case the tripping open of the circuit breaker on any one phase may be arranged in a well known manner to trip open the breaker situated in the other phases of the circuit.

It should be understood that our invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in therart without departing from the spirit of our invention.

What we claim as-new and desire to secure by Letters Patent of the United States, is:

1. An electric circuit breaker comprising a movable switch member, coacting contacts controlled thereby, operating mechanism restraining said switch member in the closed circuit position, and means responsive. to an abnormal circuit condition causing an initial movement of said switch member in the switch closing direction, said initial movement causing collapse of said operating mechanism and circuit opening movement of said switch member.

2. An electric circuit breaker comprising a movable switch member. contacts coacting therewith, an operating toggle restraining said switch member in the closed circuit position, and means responsive to an abnormal circuit condition causing an initial movement of said switch member in a closing direction independently of said operating toggle, said initial moy'ement causing collapse of said operating toggle and circuit opening movement of said switch member.

3. An electric circuit breaker comprising ment of said switch member in response to said limited movement.

4. In an electric circuit breaker including a movable switch member, a cooperating contact mounted for limited movement and operating mechanism collapsible to cause cirsaid resilient connection, and means actuated in response to said initial movement of said switch member causing collapse of said mechanism and circuit opening movement of said switch member.

5. Trippin mechanism for an electric circuit breaker aving a movable switch member, operating mechanism collapsible to cause circuit opening movement of said member and a contact coacting with said switch member, said contact mounted for limited movement, comprising a current responsive device normally maintaining said contact in a predetermined position, means resiliently biasing said switch member into engagement with said contact tending to move said contact into another position, release of said contact in response to actuation of said current responsive device causing limited movement of said switch member independently of said operating mechanism under influence of said biasing means, and means connected to said switch member directly causing trippingof said collapsible mechanism and circuit opening movement in response to said.- limited movement.

6. An electric circuit breaker comprising a movable switch member, a contact mounted for limited movement coactin therewith, overset toggle operating mechanism restraining said switch member in closed circuit position, an o ening spring for biasing said switch mem r to open circuit position in response to tripping of said toggle mechanism, means interconnecting said switch member and operating mechanism resiliently biasing said switch member independently of said opening spring into engagement with said contact in the closed circuit position,

means arranged to release said contact in response to an abnormal circuit condition, said resilient biasing means thereby causing an initial movement of said switch member in the circuitclosing direction independently oi said toggle operating mechanism, and means connected to said switch member causing tripping of said mechanism and circuit opening movement in response to said initial movement. r

7. An electric circuit breaker comprising a movable switch member and a contact mounted for limited movement coacting therewith, toggle 0 rating mechanism 0 ratively connected rough an insulating rod to said switch member, said toggle mechanism having a resilient connection with said rod arranged so that said resilient connection is stressed in the circuit closing operation, an opening spring tending to bias said toggle mechanism towards open circuit position, and tripping means comprising a current responsive device coactin with said con tact arranged so that actuation of said device releases said contact for limited movement and causes corres nding movement of said switch member t rough said resilient connection, and a member connected to said rod causing tripping of said toggle in response to said movement. I I

8. In an electric circuit breaker including a movable switch member and a contact coacting therewith, said contact mounted for limited movement, and o ratin mechanism colla sible to cause circuit opening movement of said switch member, tripping means comprising a fusible element normally restraining said contact in a redetermined position, means resiliently biasing said switch member into engagement with said contact arranged so that rupture of said fusible element causes a release of. said contact and an initial movement of said switch member independently of said operating mechanism, and means .connected ,tosaid switch member causing colla of said operating mechanism and circuit opening movement in response to said initial movement.

9. In an electric circuit breaker including a movable switch member and a contact coacting therewith, said contact mounted for limited ivotal movement and toggle operating mec anism collapsible under the influence of an opening spring to cause circuit opening movement of said switch member, tripping means for said toggle mechanism comprising a fusible element connected in serigs with the circuit breaker normally restraining movement of said contact, an underset toggle connected to said contact and engaged by said fusible element arranged so that the restraining force is borne mainly by said toggle, a resilient connection between said switch member and toggle mechanism stressed in the closed circuit position to bias said switch member into engagement with said contact whereby rupture of said fusible element causes release of said contact and an initial movement of said switch member through said resilient connection, and means actuated in response to said initial movement of said switch member directly causing tripping of said toggle mechanism and circuit opening movement.

10. In an electric circuit breaker includin a movable switch member, a contact mounte for limited movement coacting therewith, an operating toggle having a resilient connection with said switch member, said resilient connection biasing said switch member into engagement with said contact in the closed circuit position of said member, and an electromagnetic current responsive device coacting with said contact arranged so that actuation of said device releases said contact and causes limited movement of said switch member in the closing direction under influence of said resilient connection, and means connected to said switch member causing tripping of said operating toggle in response to said movement.

11. An electric circuit breaker comprising a pair of coacting contacts, operating mechanism for controlling said contacts, means responsive to an abnormal circuit condition causing initial and concurrent movement of said contacts, and means responsive to the aforesaid initial movement of said contacts causing circuit opening movement of said operating mechanism.

12. An electric circuit breaker comprising a movable switch member, coacting contacts controlled thereby, operating mechanism including a tripping toggle for restraining said switch member in the closed circuit position, and means responsive to an abnormal circuit condition causing an initial movement of said switch member, said switch member tripping said toggle during said movement causing circuit opening movement of said operating mechanism and switch member.

In witness whereof, we have hereunto set our hands.

HENRY TRENCHAM.- HERBERT C. HEATH.

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