US2679562A

US2679562A - Circuit breaker

Info

Publication number: US2679562A
Application number: US250134A
Authority: US
Inventors: Joseph A Drobney; Albert R Cellerini
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1951-10-06
Filing date: 1951-10-06
Publication date: 1954-05-25
Anticipated expiration: 1971-05-25

Description

May 25, 1954 J. A. DROBNEY ET AL 2,679,562

CIRCUIT BREAKER Filed Oct. 6, 1951 oFF oN Fg.|.

and Albert R. Cellerni.

Patented 'May 25, 1954 Joseph A. Drobney and Albert R. Cellerini, Bomen-Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa.,

tion of Pennsylvania a corpora- Application ocmber 6, 1951, serial No. 256,134

(ci. `o-ss) 14 Claims. l This invention relates to circuit breakers, and more. particularly to circuit breakers for controlling lighting and moderate power circuits.`

An object of the invention is to provide a circuit breaker having a switch member biased open and an operating handle supporting the switch member in closed position against its bias.

Another object of the invention isy to provide a circuit breaker having an operating handle and a switch member'biased open and a support memy ber on said switch member releasably engaging the handle.

A further object of the invention is to provide a circuitbreaker having an operating handle, a switch member biased open, a supportmember between the handle and the switch member and trip means for disengaging the support member from said handle to effect opening of the breaker.

Another object of the invention is to provide a small compact circuit breaker that is simple in construction, reliable inA operation and inexv pensive to manufacture.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims.

withadditional objects and advantages thereof, will be best understoodfrom the following detailed-description thereof when read in conjunctiony with the accompanying drawing.

yIn said drawing:

Figure 1 is a side elevationalview, partly in section and with the cover plate partly broken away, of a circuit breaker in the closed position embodying the principles of the invention,

Fig. 2 is a view similar to Fig. 1 but showing the parts in the tripped open position.

Referring to the drawing, the circuit breaker 'comprises a casing and a cooperating cover plate I3, a fragment of which is shown in Fig.- 1 broken away.r A stationary contact |'5` is mounted on a conducting stripV I'|` which extends through an opening in one endA wall of the casing and has a terminal connecting screw I9 at its other end. A movable switch member or arm 2| has :spaced side members 22 thereon (only one being shown) adjacent one end thereof throughwliich extendsa pin 23. The ends of the pin 23 extend into companionslots 25 (only one being shown) vin the side wallof` the casing andin the cover plate I3. The switch arm 2| at its outer end ,carriesa movable'contact 21 for cooperating-with the stationary contact |5. The switch arm 2|v is biased open by means of a spring 29 compressed between a. spring seat 28 in the basek of the cas- The invention itself, both as to construction and operation, togetherk ing I I and a spring guide '30 on the switch arm 2|. An operating handle 3| 'of moldedinsulating materialis pivotally mounted on a pin 33 supported in suitabler bearing openings (not shown) in the side wall of the 'casing I I and in the cover plate I3. AThe handle 3| extends outwardly through an openingA 31 in the casing I I 'andA 'substantiallyy closes the opening in all positions of the handle. The `inner end of the handle 3| is provided with a projection '39 having ar slightly concave surface' 4| which, in the closed position of the breaker,rk engages ther rounded upper end of a support member 43 the other end of which is pivotally connected by means of a pivot pin 45 to the side members 22 of the switch arm 2|.

A relatively light spring 4l compressed between a spring seat 49-in the casing l|I and the support memberv 43 biases'the support member counterclockwise about the pivot 45 against a projection 5|y on the casing II in whichlposition the point of contact 39-4I of the handle 3| and the support member 43 is substantially in line withr the f pivots 33 and `45, respectively, of the handle and thek support member, thus holding the switch armk 2| in the closed contact position.

The contacts are opened manually by countery .clockwise movement of the operating handle 3| from the Onposition to the Off position (indicated by dot and dash lines, Fig. 1). During this movement of the handle 3|, the friction between the. projection 39 and the end of the support 43 is not sufficient tocause rotation of the support member 43 against the bias of the spring 41. Consequently, the projection 39 isdisengaged from the support member 43 permitting the spring 29 to movethe switch arm 2| to the open position in which it appears in Fig. 2. During the manual opening movement, the support member 43 moves upwardly to the position indicated by dot and dash lines at 43a (Fig. l). The opening movement of the switch arm2| is limited by engagement thereof'with a surface 53 on the casingk and by engagement of the pin 23 with kthe upper ends of the slots 25.

The contacts'are closed manually by move-"- ment of the handle 3| from the Off (shown by dot and dash lines in Fig. l) to the On handle brings the concave surface 4I into engagement with the end of the support mem-ber 43 which is then biased by the spring 41 to the position shown in Fig. '1 substantially in line with the pivots 33-65 or slightly overset to the left of a line drawn through the centers of the pivots 33--45- It will be observed that the slots 25 are disposed at a slight angle to provide a wiping action between the contacts as they are closed.

The circuit breaker is opened automatically in response to overload currents by means of a thermally and magnetically responsive trip device indicated generally at 5l. The trip device comprises a binietal element 59 having one end suitably secured, preferably by welding, to the inner end of a conducting strip 3i which extends out through an opening in the end wall of the casing ii and is provided at its other end with a connecting screw S3. The connected ends of the bimetal element 59 and the conducting strip 6l are seated in a notch inthe casing Il in order to accurately position the trip device.

The bimetal element 59 from a point just below its point of connection with the strip 6I extends inwardly at an angle and the free end of the bimetal element 53 is connected by means of a flexible conductor S5 to the left-hand end of the switch arm 2i. Disposed adjacent the free end of the bimetal element 59 is an ear 61 formed on a projection 63 on the support member 43.

Secured to the bimetal element in a suitable manner, for instance, by welding is a resilient member or spring strip 'ii having a main body spaced from the bimetal element and extending substantially parallel thereto on the side of the bimetal away from the support member 43. A magnetic member 'i3 is rigidly secured to the bimetal element 53 and a cooperating magnetic member or armature l5 is mounted on the spring strip l. An adjusting screw 'i threadedly engaging the free end of the spring strip El and locked in place by a lock nut 1Q extends through a clearance opening in the bimetal element 53 and has its end disposed adjacent the ear Gl'.

'When an overload current occurs below a predetermined value of, for example, 1000% of normal rated current, the bimetal element 59 becomes heated by the excessive current and when heated a predetermined amount deilects toward the right (Fig. l) engaging the ear G'i and moving the support member 43 clockwise about its pivot 45 against the bias of the spring 41. During this movement, the handle 3 i, due to the friction between the surface di and the end of the support member 23, rotates counterclocliwise. This action continues until the support member 113 escapes from the concave surface 4i whereupon the spring 29 acts to move the switch arm 2| to the open position moving the support member to the position in which it is shown in Fig. 2. After escaping from the surface 4i, the upward movement of the support member 43 causes the upper end thereof to engage a projection 8| on the handle 3| and move the latter to an intermediate indicating pcsition shown in Fig. 2 in full lines.

The parts are shown in the tripped open position in Fig. 2. In this position, the spring 4l biases the support member 43 and the handle toward the Fig. l position, but since the spring 29 is stronger than the spring 4l, the parts will be held in the Fig. 2 position until the handle 3i is moved to the Reset position shown in dot and dash lines in Fig. 2. When the handle is moved to the Reset position, it frees the support member i3 which is immediately snapped countercloclrwise by the spring i1 to its position against the stop 5i. Thereafter the contacts are closed in the previously described manner by movement oi the handle 3i clockwise to the On position. During this movement the cam surface ii on the handle engages and cams the support member lli downwardly to move the switch arm to the closed position.

Upon the occurrence of an overload current above 10C0% of normal rated current, or a short circuit current, the electromagnet 13 -15 is energized sufiiciently to attract the armature 15 and bend the spring strip ii causing the screw 11 to engage and actua-te the support member 43 to thereby eifect instantaneous opening of the contacts. Following an instantaneous opening operation, the breaker mechanism is reset and the contacts closed in the previously described manner by iirst moving the handle 3l counterclockwise to the Reset position and then clockwise to the On position.

The invention provides a circuit breaker of simple construction and having a minimum number of parts. The circuit breaker is trip free of the operating handle and is provided with a thermally and electromagnetically responsive trip device, the electromagnetic trip being supported entirely on the thermal element.

While the invention has been disclosed in accordance with the provisions of the patent statutes, it is to be understood that various changes in the structural details and arrrangement of parts may be made without departing from some of the essential features of the invention.

We claim as our invention:

1. A circuit breaker comprising a movable switch member biased to open position and movable to open and close the circuit, an operating handle movable to an open position and to a closed position, a support member on said movable switch member releasably engaging said handle to maintain said switch member in the closed position, a spring biasing said support member to a normal position relative to said handle, manual movement of said handle to said open position causing release of said support member from said handle to permit opening movement of said switch member, and a trip device responsive to overload currents for engaging and releasing said support member from said handle to permit opening movement of said switch member.

2. A circuit breaker comprising a movable switch member movable to an open position and to a closed position to open and close the circuit, biasing means biasing said switch member to open position, a pivoted operating handle movable to an open position and to a closed position, a support member mounted on said switch member and releasably engaging said handle to maintain said switch member in the closed position, spring means biasing said support member about its mounting on said switch member to a normal position against a fixed stop, said handle when moved to said open position causing release of' said support member from said handle to permit said biasing means to move said switch member to open position, and a trip device operable in response to overload currents to engage and release said support member from said handle to effect automatic opening of said switch member.

3. A circuit breaker comprising a movable switch member biased to open position and movable to open and close the circuit, an operating handle movable to an open position and to a closed position, a support member disposed between said handle and said movable switch member normally releasably restraining said switch member in closed position, said support member being released from said handle upon movement of said handle to said open position to permit opening movement of said switch member, and a trip device operable in response to abnormal circuit conditions to engage and move said support member to effect release of said member from said handle to permit opening movement of said switch member.

4. A circuit breaker comprising a movable switch member biased open and movable to open and close the circuit, an operating handle movable to an open position and to a closed position, a pivotal support member disposed between said handle and said movable switch member normally releasably restraining said movable switch member in closed position, movement of said handle to said open position effecting release of said support member from said handle to permit opening movement of said switch member, and a bimetal element heated in response to overload currents and operable when heated a predetermined amount to engage said support member and eiiect release of said support member from said handle to permit opening movement of said switch member.

5. A circuit breaker comprisingr a switch member biased open and movable to open and close the circuit, an operating handle movable to an open position and to a closed position, a support member disposed between said handle and said switch member normally releasably restraining said switch member in closed position, movement of said handle to said open position effecting release of said support member from said heated a predetermined amount to engage said support member and eiiect release of said support member from said handle to permit opening movement of said switch member, and a projection on said handle engageable by said support between said handle and said switch member normally releasably restraining said switch member in closed position, stop means limiting the movement of said support member in one direction relative to said handle, spring means biasing member against said stop means, a

opening movement of said switch member.

7. A circuit breaker comprising a pivoted switch member biased open and movable to open and close the circuit, an operating handle movable to an open position and to a closed position to eilect manual opening and closing movement of said switch member, a support member disposed between said handle and said pivoted switch member normally releasably restraining said switch member in closed position, stop means limi-ting the movement of said support member in one direction relative to said handle, spring means biasing said support member against said stop means, a projection on said support member, a bimetal element having one end supported and the other end free, and thermal bending of said bimetal element causing the free end thereof to engage said projection and effect release of said support member from said handle to permit opening movement of said switch member.

8. A circuit breaker comprising a movable switch member biased open and movable to open and close the circuit, an operating handle movable to an open position and to a closed position, a support member pivotally connected to said movable switch member and releasably engaging said handle to restrain said switch member in closed position, and a trip device operable in response to overload currents to engage and release said support member from said handle and permit opening movement of said switch member.

9. A circuit breaker comprising a switch member biased open and movable to open and close the circuit, an operating handle movable to an open position and to a closed position, a support member pivotally connected to said switch member and releasably engaging said handle to restrain said' switch member in closed position, and a trip device operable in response to overload currents to engage and release said support member from said handle to permit opening movement of said switch member, and said support member when released by said trip device engaging and moving said handle to an intermediate indicating position.

10. A circuit breaker comprising a switch member biased to open position and movable to open and close the circuit, an operating handle movable to an open position and to a closed position to effect manual opening and closing movement of said switch member, a support member having yone end releasably engaging said handle and the other end pivotally engaging said switch member, a trip device comprising a bimetal element having one end supported and the other end free, said bimetal element bending when heated in response to overload currents below a predetermined value to effect release of said one end of said support member from said handle and opening movement of said switch member, and electroresponsive means operable in response to overload currents above said predetermined value to engage and eifect release of said one end of said support member and instantaneous opening movement of said switch member.

11. A circuit breaker comprising a switch member biased open and movable to open and close the circuit, an operating posi handle movable to an member, a resilient member having one end supported adjacent the supported end of said bimetal element, electroresponsive means comprising a magnetic member mounted on said bimetal element and an armature mounted on said re silient member, and said electroresponsive means when energized in response to overload currents above said predetermined value bending said resilient member and causing said resilient member to engage and release said support member from said handle to effect instantaneous opening movement of said switch member.

12. A circuit breaker comprising a switch member biased open and movable to open and close the circuit, an operating handle movable to an open and to a closed position to effect manual opening and closing movement of said switch member, a support member having one end releasably engaging said switch member, said support member having a projection thereon, a trip device comprising a bimetal element having one yend supported and the other end free, said bimetal element bending in response to overload currents below a predetermined value to engage said projection and release said support member from said handle to permit opening movement of said switch member, a resilient member having one end supported adjacent the supported end of said bimetal element and the other end free, an adjusting screw on the free end of said resilient member, electromagnetic means comprising a rst magnetic member on said bimetal element and a second magnetic member on said resilient member, said electromagnetic means when energized by overload currents above said predetermined value bending said resilient member and causing said adjusting screw to engage said projection and instantaneously release said support member from said handle.

13. A circuit breaker comprising a switch member biased open and movable to open and close the circuit, an operating handle movable to an open and to a closed position to effect manual opening and closing movement of said switch member, a support member having one end releasably engaging said switch member, said support member having a projection thereon, a trip device comprising a bimetal element having one end supported and the other end free, said blmetal element bending in response to overload currents below a predetermined value to engage said projection and release said support member from said handle to permit opening movement of said switch member, a resilient member having one end supported adjacent the supported end of said bimetal element and the other end free, an adjusting screw on the free end of said resilient member, electromagnetic means comprising a. first magnetic member on said bimetal element and a second magnetic member on said resilient member, said electromagnetic means when energized by overload currents above said predetermined value bending said resilient member and causing said adjusting screw to engage said projection and instantaneously release said support member from said handle, and said adjusting screw being adjustable to vari,T the magnetic tripping point of the breaker while the thermal tripping point remains constant.

le. A circuit breaker comprising a switch member biased open and movable to open and close the circuit, an operating handle having a plurality of projections thereon and movable to effeet opening and closing movements of said switch member, a support member having one end releasably supported on one of said projections and the other end pivotally supported on said switch member, a trip device operable in response to overload currents to engage and release said one end of said support member from said one projection to permit longitudinal movement or said support member and opening movement of said switch member, and longitudinal movement of said support member causing said one end thereof to engage another of said projections and actuate said handle to an indicating position.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,360,684 Jennings Oct. 17, 1944 2,443,090 Wise June 8, 1948 2,534,938 Woodward Dec. 19, 1950 2,568,423 Walker et al Sept. 18, 1951 2,573,306 Casey Oct. 30, 1951