US2290495A - Circuit breaker - Google Patents

Description

July 2l, 1942.

4.1.' sANDlN ET AL CIRCUIT BREAKER Filed July 27, 1939 3 Sheets-Sheet l vIJ@ WITNESSES:

July 2l, 1942. J. sANDlN ETAL 2,290,495.

CIRCUIT BREAKER Filed Ju1y`27, 1 959 s Sheets-shea 2 WITNEsSEs: INVENToR July 21, 1942. J. sANmN ETAL 2,290,495

' CIRCUIT BREAKER i Filed July 27, 1939 3 Sheets-Sheet 3 wlTNEssEs: lNvEN'rRs Patented July 2l, 194.2.

CERCUTI BREAKER Appiicaticn luly 27, i939, Serial No.- 286,822

(Cl. Zlib- 172) 1? Claims.

The invention relates particularly to circuit breakers of the type used in controlling lighting and moderate power distribution systems.

Circuit breakers of the above-mentioned type usually embody relatively complicated operating mechanisms which should not be dismantled outside of the manufacturing or assembling plant. The operating mechanism is usually equipped with a pivoted metal operating member which has a handle of molded insulating material riveted or otherwise rigidly and non-removably secured thereto. This operating member forms a part of the operating mechanism and has the relatively powerful overcentei` actuating springs, and in many cases other parts of the mechanism, connected thereto. lt is apparent that if the molded handle is broken, the mechanism must be dismantled to replace it. This results in excessive servicing charges and also in undesirable service interruption.

An object of the invention is the provision of a circuit breaker of the class described with a molded insulating handle that is removably mounted on the metal operating member of the circuit breaker operating mechanism so that the handle may be removed or replaced without dismantling the mechanism.

Another object of the invention is the provision of a circuit breaker of the class described in which the molded insulating handle is rigidly secured te a metal mounting plate which reenorces and strengthens the handle without occupying more space, the handle and its rigid mounting plate being removably mounted on the metal operating member of the circuit breaker operating mechanism.

Another object of the invention is the provision of a circuit breaker with a removable handle of molded insulating material which is attached in a novel manner to a metal mounting plate by means of which it is removably mounted on the operating member of the circuit breaker.

The features of the invention which are believed to be novel are particularly pointed out in the appended claims. For a complete understanding and disclosure of the invention, reference may be had to the following detailed description of the invention to be read in conjunction with the accompanying drawings, in which:

Figure 1 is a fragmentary vertical sectional view of a three-pole circuit breaker embodying the features of the present invention, the section being taken substantially through the center pole of the breaker and certain parts being shown in elevation;

Fig. 2 is a fragmentary sectional view of the circuit breaker operating member and the removable insulating handle taken substantially valong the line` II-II of Fig. 3;

Fig. 8 isl a fragmentary sectional View of a further modiedV handle construction and mounting, on the metal operating member of a different circuit breaker construction;

Figs.V 9 and 10 are perspective views of the operating member and handle shown in Fig. 8.

Referring tonFigure l 0f thedrawings, the circuit breaker shoWn is of the three-pole type. With the exception of the cperating handle construction and its mounting, this circuit breaker .is of the same general construction as the breaker fully described in Patent No. 2,083,304 of Ture Lindstrom, issued June 8,1937, and assigned to theassignee of the present invention. Only a brief description of the main breaker construction will be given in this application. For details of the main breaker construction and its operation, reference may be had to the aforementioned Y patent.

The circuit'breaker comprises, in general, a casing 9 of molded insulating material having a removable cover il secured thereon, stationary contact means v@cooperating movable contact means I5, a circuit breaker operating mechanism lll, and a unitary trap device 2 i.

There are three setsrof the stationaryrand movable contact meanslt and i5 forming the three poles of the breaker, only the contact means of the center pole being shown. The movable contact members 20 ofthe movable contact means i5 for the center pole are pivotally mounted at'ZZ on a movable Switch'member 23, and are biased toward the stationary contact means I3 relative te the switch member 23 by spring means Acarried by the switch member, suitable stops carried by the switch member being provided for limiting the counterclockwise movement of the contacts 2b relative to the switch member.

switch member 23 is pivotally mounted by means of a pivot pin 2t on a U-shaped main frame 2l which also supports the circuit breaker operating mechanism l1. The movable contact means of the two outer poles (not shown) are also carried by switch members which are mechanically connected for simultaneous movement with the center pole switch member 23 by means of a rigid tie bar 29 which extends transversely across the three poles of the circuit breaker. Each switch member is clamped to the tie bar 29 by a clamp 3|, and the switch members are insulated from one another by means of an insulating sleeve 33 surrounding the tie bar 29.

The poles of the circuit breaker are insulated from one another by insulating barriers 31 molded in the casing 9, which align with similar barriers 39 molded in the cover |I. Each pole of the circuit breaker is provided with an arc-extinguishing structure 4| for extinguishing arcs drawn between the contacts during interruption of the circuit. The arc-extinguishing structures may be of any suitable type but are preferably of the type fully described in Patent No.

1,896,764, issued to M. W. Brainard, February '1,

1933, and assigned to the assignee of the present invention.

The electrical circuit for each of the poles of the breaker is substantially the same. The circuit for each pole extends from an upper terminal (not shown) through' the arc-extinguishing structure 4| to the stationary contact means |3, and thence through the movable contacts 20, exible shunt conductor 43, conducting bar 45, through the electro-responsive means of the trip device 2| to the lower termin-al 41.

The operating mechanism |1 comprises the U-shaped frame 21, a pair of toggle links 49 and 5| having one end pivotally connected to the center pole switch member 23, `a-carrier lever 53 for releasably restraining the other end of the toggle links 49 and 5| in operative position, a channel-shaped operating member 55, an overcenter spring unit 51 for connecting the operating member to the knee of the toggle, and an operating handle 59.

The U-shaped frame 21 is positioned above the conductor bar 45 of the center pole and is rigidly secured to the base by means of screws 6| and 53. The screw 53 extends through the conductor bar 45 and hence the entire operating mechanism I1 and frame are at the same electrical potential as th'at of the center pole.

The toggle link 49 comprises a pair of parallel links which are joined by a bridge portion 65. One end of the toggle link 49 engages the center pole switch member 23 through the agency of a pivot pin 61. The other end of the toggle link 49 is pivotally connected to the upper end of the toggle link 5| by a knee pivot pin 69.

rIhe toggle link 5| also comprises a pair of parallel link sections which are joined by a bridge portion 1| disposed at the upper end of the link beyond the knee pivot pin 69. The bridge portion 65 is adapted to engage the bridge portion 1| when the breaker is in the fully closed position, as shown, to provide a stop for defining the limit of upward motion of the knee or" the toggle.

The overcenter spring unit 51 operatively connects the lower end of the operating member 55 with the knee pivot pin 69 of the toggle links and exerts `a strong tension force therebetween. The lower end of the overcenter spring unit pivotally engages the lower end o'f the operating member 55 through the agency of a pivot pin 13 and a pair of supporting ears carried by the operating member 55. The lower end of the toggle link 5| is pivotally connected to the carrier lever 53 by a pivot connection 11.

The channel-shaped operating member 55 has its sides pivotally connected to the frame 21 by means of a pivot pin 80. The carrier lever 53 comprises parallel bell crank levers which are joined by a bridging section 19 which extends parallel to the base of the casing. The carrier 53 is pivoted to the frame at the apex of the bell crank levers by means of a pivot pin 8|. Th'e overcenter spring unit 51 at all times exerts a force on the carrier 53 transmitted through the toggle link 5 l biasing the carrier lever in a clockwise direction, and a latching lever 83 is provided for restraining the carrier lever 53 in operative position. The latching lever 83 also comprises a pair of parallel sections which are joined by bridging portions 85 and 81. One end of the latching lever 83 is pivoted to the frame 21 by `a pivot pin 89. The bridge portion 85 of the latching lever 83 normally overhangs and engages the bridge portion 19 of the carrier lever 53 and thus holds the carrier lever in an operative position by preventing it from moving in a clockwise direction under the bias of the operating spring 51 and the contact springs 25. The lower free end of the latching lever 83 is releasably restrained by pivoted latch-engaging mechanism 9| supported on the bridging portion 81, the latch mechanism 9| being normally restrained by a part of the trip device 2|.

The trip device 2l is preferably of the type fully disclosed in Patent 2,043,306, issued to Jerome Sandin, June 9, 1936, and assigned to the assignee of the present invention. This trip device has a thermally responsive `and a magnetically responsive element electrically connected in each' pole of the breaker, and is operable upon the occurrence of predetermined overload conditions in any one of the poles of the breaker to effect release of the latching lever 83, and consequently, opening of all of the poles of the circuit breaker. Suitable means are provided for restoring the parts of the trip device to an operative condition following each tripping operation.

The operation of the circuit breaker as thus far described is briefly as follows. The operating handle 59 which is rigidly secured to the top of the operating member 55, is moved in a clockwise direction about the pivot pin by its h'andle knob which projects through an elongated opening 82 in the top of the cover Il. When the operating handle has been moved a short distance, la projection (not shown) on the underside of the operating member engages the bridge portion 65 of the toggle link 49, and upon continued movement of the handle, positively sets the knee of the toggle in motion towards the base. At the same time, the operating spring unit 51 has been moved across the center line of the link 5|, where it exerts a force tending to move the knee pivot pin 69 towards the base. The movement of the various parts of the operating mechanism is now automatic and all of the contacts are simultaneously opened with a snap action.

To close the circuit breaker, the operating handle 59 is moved in a counterclockwise direction about the pivot point 89, causing the line of action of the overcenter spring unit 51 to be moved over the `center line of the toggle link 5|. The operating spring unit then exerts a force biasing the knee pivot pin 69 outwardly from the base, causing extension of the toggle, and closing the contacts of the lbreaker also with a snap action.

When the breaker contacts are in the fully closed position and an overload or short circuit occurs in the circuit vcontrolled by any one of the poles of the breaker, the latch-engaging mechanism 9| is released by the trip device 2| and the latching lever 83 then moves counterclockwise about; its pivot 89 under the biasing influence of the operating spring unit 51, transmitted thereto through the carrier 53. The counterClockWise movement of the latching lever 83 causes its bridge portion 85. to release the bridge portion 19 of thecarrier lever 53.` The carrier lever 53 is then moved clockwise about its pivot 8| under the biasing action of the overcenter spring unit 51 and the force of the contact springs 25, causing collapse of the toggle links and simultaneous opening of all of the contacts of the circuit breaker.

A pair of rollers 93 disposed on opposite sides of the channel-shaped operating member 55, are adapted to engage the edge of the parallel sections of the carrier lever 53 to limit motion of the operating member 23 in a clockwise direction, the rollers 93 also providing a means for resetting the carrier and latchingY levers following opening of the breaker bythel trip device.

To reset the circuit breakermechanism following an automatic tripping operation thereof, the operating handle 59 must be moved .in a clockwise direction about the pivot axis 89 to its off posi tion. This movement of the operating handle causes the rollersr93 to engage and reset the carrier lever 53 and the latching lever 83 to their latching positions. The breaker may then be reclosed by moving the operating handle in a counterclockwise direction to the on position. Y

Since the circuit breaker operating mechanism |1 is at the same electrical potential as the center pole of the circuit breaker, it is necessary that the operating handle 59 be of insulating material. Prior to the present invention, it has been the practice to provide an operating handle of molded insulating material, and to rigidly secure the molded handle to the metal operating member 55 by means of pin inserts molded into the handle, the ends of which pass through openings in the top of the operating member 55 and which were riveted over against the underside of the top of the operating member 55. The operating handle was thus rigidly but non-removably secured to the metal operating member. From the above description of the circuit breaker operating mechanism, it is apparent that the'mechanism should not be dismantled outside of the manufacturing or assembly plant, due to the connection of the operating member 55 to the powerful tension spring 51 and otherparts of the circuit breaker mechanism, and to the mounting arrangement of the various parts. Consequently, with the abovementioned prior construction and non-removable mounting of the operating handle, excessive servicing charges and undesirable interruptions to service were incurred when the molded insulating handle was broken and had to be replaced.

According to the present invention, these diiculties are obviated by the provision of a molded insulating handle which is removably secured in a novel manner to the operating member 55. Referring to Figs. 1 through 6 of the drawings, the operating handle 59 comprises a handle 95 formed of molded insulating material and a metal mounting plate 91, which is rigidly secured to the underside of the molded handle 95. The molded handle 95 is provided with an elongated closure portion 99 which is adapted to close the opening 82 in the cover I in any position of the operating handle, and with a handle knob ||l| which projects perpendicularly from the closure portion 99 intermediate the ends thereof and is adapted to extend through the op egning 82 in thepcover. The

metal mounting plate 91l is rigidly secured to the flat underside ofv theclosure portion 99 of the molded handle by means of a plurality of -pin inserts |53, four in the embodiment shown, which are molded into the material of the closure portion99. The pin inserts |93 have hollow end lportions |95 (Fig. Ll) projecting from the underside of the closure portion99, which extend through openings |51 (Fig. 5) providedtherefor in the metal mounting plate 91. The ends of the hollow projections |95 of the pin inserts |03 are swaged or riveted over against the undersidev of the mounting plate 91, thusA rigidly securing the molded handle-95 to the mounting plate 91.

The handle mounting plate 91 is provided at one end witha pair of reversely bent flanges or hook portions |99, which are adapted to engage and hook over the upper edge of the'top of the metal-operatingmember 55 as shown in Fig. 2, to mountthe operating handle 59onfthe. operating vmember. The opposite end of the handle mounting plate 91 extends beyond thelower end of the closure portion 99 of the moldedhandle 95, and this end is provided with a plurality of openings for receiving a plurality of mounting screws I3 which threadedly engage openings I5 (Fig. 6) provided therefor inthe channel-shaped metal Voperating member 55. The operating handle 59comprising the metal. mounting plate 91 and the molded handle portion 95 is thus removably secured to the top of themetal operating member 55V by means of thereversed flanges or hooks |99 and the fastening screws` H3.l The side edges-of the metal mounting plate 91 are preferably bent inwardly to provide side flanges ||1 which extend along the sides of the channelshaped operatingmember 55, as shown in Fig. 3. The side flanges |1 serve. to stiften and strengthen the handle mounting plate 91. The molded insulating handle 95 is also provided .With side flanges H9 on oppositersides of the closure portion 99 thereof, which overlap the side flanges ||1 of the metal mounting plate 91.

A slight modification ofthe invention is shown in Fig. 7. In this modification, the' molded handle 95 and the handle mounting plate 91 are of the same general construction as the embodiments shown in Figs. 2 through 5, with the exception of the manner in which the molded handle 95 is secured to the mounting plate. The molded handle 95 is secured to the metal mounting plate 91 in this modication, by a plurality of pins |29 which areI rigidly secured to the mounting plate 91 and project upwardly therefrom- The upper endsy of the pin inserts |20 are provided with enlarged head portions |2|, and the handle portion 95' is molded on the pins |20 directly against the mounting plate 91.

If desired, the reverse flanges or hook portions |09 or |99 may be omitted, and this end of the metal mounting plate 91 extended'beyond the upper end of the molded handle and provided with openings for receiving fastening screws which engage through this end of the mounting plate and thread into openings provided in an extended portion of the top of the operating member 55 the same as for the lower end of the mounting plate. Also, as an alternative construction, the side anges of the mounting plate may be made of greater width and the fastening screws passed through the side flanges into the sides of the operating member for removably securing the operating handle to the operating member..

A further modification of the invention is shown in Figs. 8, 9 and 10. In this modication the circuit breaker, only a portion of the operating mechanism of which is shown, is of the same construction as the circuit breaker disclosed in Patent No. 2,130,904, issued to Jerome Sandin, September 20, 1938, and assigned to the assignee of the present invention. For details of the complete construction and operation of the main circuit breaker structure, reference may be had to the above mentioned Sandin patent.

A yoke-shaped metal operating member |3| which forms part of the circuit breaker mechanism has legs |33 which are pvotally connected to the U-shaped frame |35 by a pivot pin |31. A pair of overcenter springs |39 (only one being shown) operatively connect the operating member |3| to the knee of the toggle links |4| and |43. The upper end of the toggle is restrained in operative position by a releasable carrier |45 which is normally held in operative position by a part of the trip device (not shown). The lower end of the toggle is pivotally connected to the center pole switch member (not shown).

The operating handle |41 is composed of molded insulating material and has an arcuate closure portion |49, downwardly projecting sides |5l, and projecting handle knob |53. The underside of the closure portion has a recess |54 formed therein to closely t the top of the metal operating member |3|, and the sides 15| of the handle are provided with grooves |55 on their inner surface for closely fitting the legs |33 of the metal operating member when the handle is in mounted position on the operating member. A pin insert |51 is molded into the material of the handle in the center of the recess |54 and the projecting endof this pin fits closely but removably into an opening |59 provided therefor in the top of the operating member |3|.

The sides |5| of the operating handle are provided with screw receiving openings |6|, and the handle is removably secured in mounted position by fastening screws |63 which pass into the openings |6| and thread into openings |64 in the legs |33 of metal operating member |3I.

The load on the operating handle |41 during operation of the breaker is mainly transmitted to the yoke-shaped metal operating member |3| at the grooves |55 and at the pin insert |51. The load is also partially transmitted at edges of the recess |54, the ridges |55, and by the fastening screws |63. It is desirable to have a fairly close fit between the above-mentioned parts, otherwise the molded handle might be loose and certain portions are likely to be excessively stressed.

If the operating handle should break, it is only necessary to remove the screws |63 and slide the handle |41 off of the top of the operating member I3 I, and replace the handle by a new one.

In this modication as well as in all of the other embodiments, the screw fastenings which secure the handle to the operating member are inaccessible when the cover of the circuit breaker is on the casing, it being necessary to irst remove the cover to obtain access to these screws. The molded handle in this last modification is also reenforced and strengthened by metal of the operating member.

The invention provides an insulating operating handle which in itself is reenforced and strengthened by a metal member on which it is mounted, and the handle is removably mounted on the metal operating member of the circuit breaker mechanism. With this construction, the operating handle may be easily removed without dismantling the circuit breaker mechanism. Operating handles of this construction may be supplied to the customer so that in the event of handle breakage, a new operating handle may be substituted without undue interruption to the service.

The invention has been disclosed as applied to a, specified type of circuit breaker. It is to be understood, however, that the invention is applicable to any type of circuit breaker having an operating mechanism of a construction which should not be dismantled.

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 thereof may be made without departing from the spirit of the invention. It is desired, therefore, that the language of the appended claims be given the broadest construction permissible in the light of the prior art.

We claim as our invention:

1. In a circuit breaker having relatively movable contacts, an operating mechanism for opening and closing said contacts, said operating mechanism having a metal operating member movably mounted on a fixed support for manually operating said mechanism, an operating handle having an enlarged base portion and an integral projecting handle portion both of molded insulating material, a metal mounting plate rgidly secured to the underside of the base portion of said operating handle by a plurality of short pin inserts molded in the underside of the enlarged base of the operating handle, and means including said metal mounting plate for removably securing said operating handle to said metal operating member.

2. In a circuit breaker having relatively movable contacts, an operating mechanism for opening and closing said contacts, said operating mechanism having a metal operating member movably mounted on a fixed support for manually operating said mechanism, a movable operating handle having a handle portion of molded insulating material and a metal mounting plate rigidly secured to the underside of said molded handle portion, said metal plate having a reversely bent flange for engaging and hooking onto an edge of said metal operating member, and means including said flange for removably securing said operating handle to said metal operating member of the operating mechanism.

3. In a circuit breaker having relatively movable contacts, an operating mechanism for opening and closing said contacts, said operating mechanism having a metal operating member movably mounted on a fixed support for manually operating said mechanism, a removable operating handle having an enlarged base portion and an integral projecting handle portion both of molded insulating material, and a metal mounting plate rigidly secured to the underside of the base portion of said operating handle by a plurality of short pin inserts molded in the underside of the base portion of said operating handle, said plate having a portion extending beyond at least one edge of said molded handle portion and provided with a plurality of openings for receiving mounting screws, said mounting plate being removably secured to said metal operating member by a plurality of mounting screws.

4. In a circuit breaker having relatively movable contacts, an operating mechanism for opening and closing said contacts, said operating mechanism having a metal operating member movably mounted on a fixed support lor manually operating said mechanism, a removable operating handle having a handle portion oi molded insulating material and a metal mounting plate rigidly secured to the underside of said molded handle portion, said mounting plate having a reversely bent flange at one end for engaging and hooking under an edge of said metal operating member, the other end oi' said mounting plate extending beyond the end of said molded handle portion and having a plurality oi' openings for receiving mounting screws, said mounting plate and its rigid molded handle portion being removably secured to said metal operating member by means oi' said ange and a plurality of mounting screws engaged in said openings and threaded into said metal operating member.

5. In a circuit breaker having relatively movable contacts, an operating mechanism for opening and closing said contacts, said mechanism having a yoke shaped metal operating member pivoted to a xed support, and spring means connected to said operating member for actuating said contacts, an operating handle of molded insulating material having an enlarged integral base portion and an integral projecting handle portion both of the insulating material of the handle, said enlarged base portion and said operating member having closely intertting portions which mainly transmit the force applied to said handle to said operating member during operation of the breaker and which permit removal of said operating handle from said operating member, fastening means for removably securing the base portion of said handle to said operating member, said fastening means being disposed to be secured and released from the outer side of said handle without disturbing any of the parts of said operating mechanism.`

6. In a circuit breaker having relatively movable contacts, an operating mechanism for opening and closing said contacts, said mechanism having a yoke shaped metal operating member pivoted to a xed suport, and spring means connected to said operating member for actuating said contacts, an operating handle of molded insulating material having an enlarged base portion and an integral projecting handle portion, the inner side of the base portion of said handle having a recess therein to closely t over the outer end of said yoke shaped operating member for mainly transmitting the operating force applied to said handle to said operating member, and means including a plurality of screws for removably securing said operating handle in mounted position on said operating member, said screws being disposed to be inserted and removed from the outside of said handle and operating member Without disturbing any of the parts of said operating mechanism.

7. In a circuit breaker having relatively movable contacts, an operating mechanism for opening and closing said contacts, said mechanism having a yoke shaped metal operating member pivoted to a fixed support, and spring means connected to said operating member for actuating said contacts, an operating handle of molded insulating material having an enlarged base portion and an integral projecting handle portion, the base portion of said handle having sides provided with grooves which closely fit the legs of yoke shaped operating member, a projecting pin insert molded in the underside of the base section oi' the handle fitting closely in an opening provided therefor in the top of the operating member, and means for removably securing the handle in mounted position on said operating member.

8. In a circuit breaker, a casing of insulating material having a removable cover, circuit breaker operating mechanism in said casing having a metal operating member movably mounted on a fixed support in said casing, an operating handle of molded insulating material having a handle knob which projects through and is movable in an opening provided therefor in the cover and having an enlarged closure portion beneath said opening for closing said opening in any portion 0I' said handle, means including one or more iastening screws for removably securing said handle on said operating member, said screws being disposed to be inserted or removed from the outside of said handle Without disturbing any part of said mechanism, the major portion of the handle and all of the knob portion thereof which projects outside said casing being oi' solid insulating material.

9. In a circuit breaker, relatively movable contacts, operating mechanism for opening and closing said contacts including a metal operating mem-ber movably mounted on a xed support for manually operating said mechanism, an operating handle having an enlarged base portion and an integral projecting handle portion both of molded insulating material, said operating handle having an inner surface conforming to the shape of the outer portion of the metal operating inember to transmit the major portion of the operating force to the mechanism upon operation of the handle, one or more screws for removably securing said operating handle to said operating member, said screws being disposed to be inserted and removed from the outside of the handle Without disturbing any of the parts of said mechanism, the major portion of said handle and all of the exposed portion of the handle projection thereof being of solid insulating material.

10. In a circuit breaker having relatively movable contacts, an operating mechanism for opening and closing said contacts including a yoke shaped metal operating lever pivoted on a xed support for manually operating said mechanism, spring means connected in tension to said operating lever and movable thereby for actuating said contacts, an operating handle having an enlarged base portion and an integral projecting handle portion both of molded insulating material, said operating handle having an inner surface conforming to the shape of the outer portion of the metal operating lever to transmit the major portion of the operating force to said operating lever upon operation of the breaker by said operating handle, one or more fastening screws for removably securing said operating handle to said operating lever, said screw or screws being disposed to be inserted and removed from the outside of the operating handle without disturbing any of the parts of said mechanism, the major portion of said handle and all of the exposed portion of the handle projection thereof being of solid insulating material.

JEROME SANDIN. ROBERT H. NAU,

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