Supporting And Spring-charging Means For Circuit Breaker

Abstract

A circuit breaker comprises improved means for supporting the parts of the circuit breaker to provide for easier assembly of the breaker and to provide operational advantages. A spring-charged means is held in charged position by a latch member engageable with a portion of a closing cam, and is released by rotation of said closing cam.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS

Certain features that are herein disclosed are disclosed and claimed in the following applications which are filed concurrently herewith: Ser. No. 770,295, Richard Hauser; Ser. No. 770,305 now U.S. Pat. No. 3,544,932, Edmund Kuhn; Ser. No. 770,297, Fred Bould; Ser. No. 770,149, Fred Bould; and Ser. No. 770,236 now U.S. Pat. No. 3,544,931, Nagar Patel.

BACKGROUND AND OBJECTS OF THE INVENTION

It is desirable, in the development of improved circuit breakers, to provide a structure that is relatively easy to assemble. It is important to avoid sacrificing reliability of operation for manufacturing advantages. Thus, an object of this invention is to provide an improved dependable circuit breaker that is relatively easy to assembly and that is provided with improved means for supporting the parts such that the parts can reliably withstand the forces that operate on the parts during operation of the circuit breaker. Another object of this invention is to provide an improved spring-charging means and spring-charged closing means including a closing cam, to effect closing of the contacts.

SUMMARY OF THE INVENTION

An improved circuit breaker comprises a metallic housing structure and a circuit breaker mechanism supported on the housing structure. The housing structure comprises a base plate and a pair of spaced generally parallel sideplates connected to the base plate with a pair of spaced generally parallel center plates connected to the base plate within the widthwise dimension of the sideplates. A crankshaft is supported on the center plates with a closing cam supported on the crankshaft between the center plates and with a pair of springs connected to the crankshaft at the opposite sides of the center plates to provide stored-energy means for closing the circuit breaker contacts. A jackshaft, that is common to all of the poles and pivotally movable to operate the movable contacts for all of the poles, is supported at the opposite ends thereof in bearings mounted on the sideplates and at the center portion thereof in bearings on the center plates. The bearings on the center plates are open at one side to permit movement of the jackshaft into the open center plate bearings to facilitate assembly of the circuit breaker. The forces acting on the jackshaft during operation of the circuit breaker operate away from the openings of the bearings on the center plates. A linkage, that is supported on one side of one of the center plates, engages a trip bar, that is supported on bearings on one center plate and one of the sideplates, to latch the circuit breaker in the reset operating position. The latching forces act on the trip bar in proximity to the center plate so that the load is adjacent to one of the bearing supports to thereby reduce bending loads and possible consequent deflections of the trip bar. The closing cam comprises twin cam members with a roller latch supported between the twin cam members. A closing latch engages the roller latch to hold the closing cam in the charged position until it is desired to close the circuit breaker whereupon the closing latch is operated to release the roller, and the stored-energy of the closing springs serves to operate the crank to thereby operate the jackshaft to thereby close the contacts.

When the closing springs are charged and the closing cam is latched with the circuit breaker contacts in the open position, a closing member is manually depressible to unlatch the closing latch to release the charged closing springs which then operate to close the contacts. Interlock means, which may be termed a nonbrute-force interlock means, is provided to render depression of the closing member ineffective when the springs are charged and the contacts are in the closed position so that an operator may be able to depress the closing member without releasing the closing latch and charged closing springs when the contacts are in the closed position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an end view, with parts broken away and with certain parts left out for the purpose of clarity, of a circuit breaker constructed in accordance with principles of this invention;

FIG. 2 is a sectional view taken generally along the line II-II of FIG. 1;

FIG. 3 is a sectional view, with parts left out for the purpose of clarity, taken generally along the line III-III to illustrate the support and positions of parts of the breaker;

FIG. 4 is a view similar to FIG. 3 illustrating the parts in the tripped position;

FIG. 5 is a sectional view taken generally along the line V-V of FIG. 1 illustrating the handle-operating mechanism;

FIG. 6 is a view similar to FIG. 5 illustrating the charging position of the handle-operating mechanism;

FIG. 7 is a view similar to FIG. 2, of part of the operating mechanism shown in FIG. 2, with the parts being shown in the spring-discharged contact-closed position;

FIG. 8 is a view similar to FIG. 7 with the parts being shown in a spring-discharged contact-open position;

FIG. 9 is a view similar to FIG. 7 with the parts being shown in the spring-charged contact-closed position;

FIG. 10 is a sectional view illustrating the support of the center plates, closing cam, crankshaft and trip shaft;

FIG. 11 is a side sectional view, with parts broken away for the purpose of clarity, illustrating the manual release means;

FIG. 12 is a view similar to FIG. 11 illustrating the position of the manual release means operated to release the closing cam with the contacts in the open position;

FIG. 13 is a view similar to FIGS. 11 and 12 illustrating the position of the manual release means operated with the circuit breaker contacts in the closed position. This view illustrates the means defeating the operation of the manual release means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, there is shown in FIGS. 1 and 2 a three-pole circuit breaker 5 comprising a housing structure 7 and a circuit breaker structure 9 supported on the housing structure 7.

The housing structure 7 comprises a metallic base plate 11, a pair of spaced metallic sideplates 13 secured to flanges of the base plate 11 by means of bolts 15, a pair of metallic spaced center plates 17 secured to the base plate 11, in a manner to be hereinafter specifically described, and a backwall structure indicated generally at 19. The backwall structure 19 is more specifically described in the above-mentioned copending application of Fred Bould Ser. No. 770,149.

The circuit breaker structure 9 is a three-pole structure comprising a stationary contact 21 and a movable contact 23 for each pole unit. The stationary and movable contact structures 21, 23, along with the supports thereof, are more specifically described in the copending applications of Fred Bould, Ser. No. 770,149 and of Fred Bould et al., Ser. No. 770,297. Each of the movable contacts 23 is supported on a conducting contact arm 25 that is pivotally supported on a terminal conductor 27 by means of support means 29. In each pole unit, a separate insulating connecting member 31 is pivotally connected at one end thereof to the contact arm 25 and at the other end thereof to a lever 33 that is welded to a common jackshaft 35. As can be seen in FIG. 1, the jackshaft 35 extends across all of the poles of the circuit breaker, and there is a separate lever 33 for each pole unit welded to the jack shaft 35. Only one of the contact structures is shown in FIG. 1. The contact structures for the center pole unit and for the left-hand (FIG. 1) pole unit are left off of the drawing in FIG. 1 merely for the purpose of clarity. It can be understood that the contact structures for all three pole units are the same as the one contact structure shown in FIGS. 1 and 2.

During assembly of the circuit breaker, the lever members 33 are first welded to the jackshaft 35. Bearing plates 37 (FIG. 1) are then positioned on the ends of the jackshaft 35 with the jackshaft fitting within openings in the bearing plates 37. The jackshaft 35 and bearing plates 37 are then moved into the position seen in FIGS. 1 and 2 with the jackshaft 35 moving into open-sided slots or bearings 39 (FIG. 2) in the center plates 17, and the bearing plates 37 are then bolted, by means of bolt means 41 (FIG. 1), to the sideplates 13. With the jackshaft 35 in the assembled position seen in FIG. 1 the jack shaft 35 is pivotally supported on the sideplates 13 by means of the bearing plates 37, and additional pivotal support is provided for the center portion of the jackshaft 35, on the opposite sides of the center lever 33, by means of the open-sided bearings 39 in the sideplates 17. As will be hereinafter apparent, the forces acting on the jackshaft 35 by means of the operating mechanism are such as to act away from the openings of the open-sided bearings 39 in the center plates 17 so that the jackshaft 35 is given effective support in the bearings 39 of the center plates 17. With the provision of open-sided bearings 39, the lever members 33 can be welded to the jackshaft 35 prior to assembly of the jackshaft 35, and the jackshaft 35 is readily assembled into the supported position seen in FIGS. 1 and 2.

The connecting members 31, levers 33 and jackshaft 35 are part of a stored-energy spring-closing mechanism 45 that is operable to close the contacts 23, 21. The mechanism 45 comprises a link member 47 that is pivotally connected, at one end thereof, to the lever 33 of the center pole unit by means of a pin 49. The link 47 is pivotally connected at the other end thereof to a link 51 by means of a pin 53. A roller member 55 is mounted on the pin 53 to cooperate with a closing cam 57. The link 51 is pivotally connected at the other end thereof to a latch member 59 by means of a pin 61. The latch member 59 is mounted for pivotal movement on a fixed pivot 63 (FIGS. 3 and 4) that is supported on the plate 17 that is seen on the left in FIG. 1. As can be understood with reference to FIGS. 1, 3 and 4, the links 59 and 51 are positioned on the left-hand side of the left center plate 17 (FIG. 1). A tension spring 64 is supported at one end thereof on a stationary pin 65, and operatively connected to the pin 61 at the other end thereof in order to reset the linkage following a tripping operation in a manner be be hereinafter described. As can be seen in FIGS. 3 and 4, the latch member 59 engages a trip shaft 69 that is a rod with a cutout portion 71 near where the latch 59 engages the periphery of the trip shaft 69. The cutout portion 71 is provided so that when the trip shaft 69 is rotated in a counterclockwise direction from the FIG. 3 position to the FIG. 4 position the latch member 59 will be free to move to the tripped position seen in FIG. 4.

As can be understood with reference to FIGS. 1 and 10, a trip shaft support bearing 73 is mounted between the center plates 17 during the assembly operation of the circuit breaker. With the bearing 73 in position, the trip shaft 69 is moved into the supported position on the bearing 73, and thereafter an outrigger support bearing member 75 is moved into position to provide an outrigger support for the other end of the trip shaft 69. The outrigger support bearing 75 is then secured in the mounted position seen in FIG. 10 by means of securing means 77. With the latch member 59 being mounted on the outside of one of the center plates 17 to engage the trip bar 69 in proximity to the one end of the trip shaft, the latch load is supported primarily on the trip shaft support bearing 73. This construction reduces the bending loads on the trip shaft 69 and provides an effective bearing support that is relatively easy to assembly.

Referring to FIG. 10, it will be noted that the closing cam 57 comprises a pair of twin cam plates 81 and a center spacer plate 83. The center spacer plate 83 does not fill the space between the twin cam plates 81, and a roller latch member 85 is rotatably supported on the twin plates 81 between the twin cam plates 81. The cam member 57 is fixedly secured to a crankshaft 87 that is rotatably supported on a pair of bearings 89 that are fixedly secured to the center plates 17 in openings in the center plates 17. Tubular spacing members 91 are supported on the crankshaft 87. A pair of crank arms 93 (FIG. 1) are fixedly mounted on the crankshaft 87 in proximity to the opposite ends of the crankshaft 87. A ratchet member 95 (FIG. 1) is fixedly secured to the crankshaft 87, and a pawl 96 is supported on one center plate to cooperate with the ratchet 95. A separate tension spring member 97 is operatively connected at one end thereof to each of the crank arms 93. As can be understood with reference to FIG. 2, each of the spring members 97 is connected, at the other end thereof, to a pin 99 that is secured to the center plates 17.

A handle-operating mechanism indicated generally at 105 (FIGS. 1, 5 and 6) is provided for manually charging the closing springs 97. The handle-operating mechanism 105 operates a crank member 107 that is fixedly connected to the crankshaft 87. A generally U-shaped supporting plate 109 is mounted on the base plate 11 by means of bolt means 111. A generally U-shaped member 113 is pivotally mounted on a pin 115 between the opposite legs of the supporting plate 109. The member 113 is spring biased in a clockwise (FIGS. 5 and 6) direction by means of a torsion spring 117. The torsion spring 117, which is coiled around the pivot pin 115, engages a pin 119 on the stationary bracket 109 and a pin 121 on the member 113 to provide the bias. The U-shaped member 113 is provided with an extension 123 that receives a handle rod 125. A generally U-shaped hook member 129 is pivotally supported on and between the legs of the member 113 by means of a pin 131. The member 129 is biased in a clockwise (FIGS. 5 and 6) direction about the pin 131 by means of a torsion spring 133 that engages the member 129 at one end thereof and the pin 121 at the other end thereof. A pin 135 is fixedly supported between the legs of the U-shaped hook member 129 to engage the crank 107 in a hook portion 137 of the crank 107.

As can be understood with reference to FIG. 2, a latch member 138 is pivotally mounted on a pin 138', between the center plates 17, and biased in a clockwise direction to the latching position seen in FIG. 2 by means of a torsion spring 140. In the latched position, the latch member 138 engages the roller 85 to latch the closing cam 57 and crankshaft 87 to prevent counterclockwise movement of the closing cam 57 and crankshaft 87.

The circuit breaker is shown in FIG. 2 in the contact-open position with the stored energy closing springs 97 in the charged condition. As shown in FIG. 2, the (FIGS. support pin 94 of the movable end of the tension spring 97 is below a line through the center of the spring support 99 and the center of the crankshaft so that the charged tension springs 97 are operating to bias the crankshaft 87 in a counterclockwise (FIG. 2) direction. Counterclockwise movement of the crankshaft 87 is prevented by the engagement of the latch member 138 with the latch roller 85 that is mounted on the closing cam 57. The latch member 138 is manually operated to the unlatching position by operation of closing means indicated generally at 139 (FIGS. 2 and 11--13). The closing means 139 comprises a manually operable closing member 141 that is pivotally supported between the sideplates 17 on a pin 143 and biased in a counterclockwise direction by means of a torsion spring 145. An elongated member 147 is pivotally mounted, intermediate the ends thereof, on the member 141 by means of a pin 149. A bellcrank lever 151 is pivotally mounted between the center plates 17 on a pin 153. As can be seen in FIG. 11, one leg of the bellcrank 151 is positioned opposite the lower end of the member 147 and the other leg is positioned opposite a surface 155 of the latch member 138. An elongated arm member 157 is connected at one end thereof to the pin 49 (FIG. 2). A roller or fulcrum member 161 (FIG. 11) on the other end of the member 157 rides in a slot 163 in one of the center plates 17.

During assembly of the circuit breaker, the trip shaft bearing 73 (FIG. 10), bearings 89, crankshaft 87, enclosing cam 57, latch member 141, latch 59 (FIGS. 3 and 4) and closing means 139 (FIGS. 11--13) are mounted on the center plates 17 which are bolted in a fixed spaced parallel relationship against three spacing and supporting blocks 167 (FIGS. 2 and 10). As can be seen in FIG. 10, bolt members 169 are used to bolt the center plates 17 against the spacing and supporting blocks 167. In addition to having transverse openings for receiving the bolts 169, each of the spacing and supporting blocks 167 is provided with a vertical tapped opening for receiving a bolt 171. Thus, when it is desired to mount the center plates 17, along with the parts supported by the center plates 17, on the housing structure, the center plates 17 and spacing and supporting blocks 167 are moved into the position seen in FIGS. 2 and 10, and a separate bolt 171 is threaded into the tapped opening in each of the spacing and supporting blocks 167 to thereby fixedly support the center plates 17 on the base plate 11.

As was hereinbefore set forth, the circuit breaker is shown in FIG. 2 in the contact-open position with the stored-energy closing springs 97 charged and with the latch 138 engaging the roller latch 85 to latch the crankshaft 87 in the latched position. The roller 55 is positioned in a depression 174 of the surface of the closing cam 57. When it is desired to close the circuit breaker, the manually operated closing member 141 is pressed in from the front of the circuit breaker. This movement pivots the member 141 in a counterclockwise direction about the pin 143 carrying the pivot 149 and the member 147 inward. As can be seen in FIG. 2, when the circuit breaker contacts are in the open position the member 157 is held to the left by means of the lever 33 to position the fulcrum member 161 at the left-hand end of the slot 163. Thus, upon inward movement of the members 141 and 147, the upper end of the member 147 engages the fulcrum member 161, and the member 147 is pivoted about the pivot 149. During this movement, the lower end of the member 147 engages the generally vertical leg of the bellcrank lever 151 to pivot the bellcrank lever 151 in a clockwise direction about the pivot 153 whereupon the generally horizontal leg of the bellcrank lever 151 engages the surface 155 of the latch 138 to pivot the latch 138 in a counterclockwise direction about the pivot 139 to thereby release the roller 85. The closing means 139 is shown in the actuated position in FIG. 12 wherein the latch 138 is operated to the unlatching or releasing position. When the roller 85 is released, the closing cam 57 and crankshaft 87 are free to rotate in a counterclockwise direction, and the closing springs 97, operating on the crank arms 93, operate to rotate the crankshaft 87 from the charged position seen in FIG. 2 to the discharged position seen in FIG. 7. With the latch 59 engaging the trip shaft 69 in the latch position to prevent counterclockwise movement of the latch 59 about the pivot 63, the closing cam 57 will force the roller 55, and the link 47 to the closed position. As can be seen in FIG. 7, the roller is moved on a closing cam surface 175 of the closing cam 57 to force the roller 55 and link member 47 to the closed position. During this closing movement of the link member 47, the lever 33 of the center pole unit is forced in a counterclockwise direction to rotate the jackshaft 35 to the closed position. As the jackshaft 35 rotates to the closed position all three of the levers 33 of the three pole units are moved with the jackshaft to the closed position forcing the connecting members 31 (FIG. 2) to the closed position to thereby pivot the three movable contact arms 25 about the pivot securing means 29 to the closed position wherein the contacts 23 engage the contacts 21. This closing movement compresses backup springs 177 in the three pole units. As can be understood with reference to FIG. 7, the engagement of the closing cam surface 175 with the roller 55 serves to maintain the link member 47 in the closed position to thereby maintain the jackshaft 35 and contacts in the closed position.

With the contacts in the closed position and the closing springs discharged (FIG. 7) the circuit breaker will be automatically tripped open, in response to an abnormal or overload current condition above a predetermined value in any of the poles, by operation of a trip means indicated generally at 179 in FIG. 1. The trip means 179, which is more specifically described in the above-mentioned copending application of Nagar Patel Ser. No. 770,236 (now U.S. Pat. No. 3,544,931) , operates automatically in response to an abnormal or overload current condition in any of the pole units to rotate the trip shaft 69 in a counterclockwise (FIG. 7) direction from the latching position seen in FIGS. 3 and 7 to the unlatched or tripped position seen in FIGS. 4 and 8. As is best understood with reference to FIGS. 3 and 4, when the trip shaft 69 is rotated counterclockwise to the tripped position the trip shaft 69 moves to permit the latch member 59 to move in the notch 71 thereby permitting the latch member 59 to move in a counterclockwise direction about the pivot 63. The compressed contact springs 177 (FIG. 2) and an opening spring 180 (FIG. 1) then operate to move the contact arms 25 toward the open position which movement occurs because the pivot 61 is free to move from the position seen in FIG. 3 to the position seen in FIG. 4 so that the link 51 can move to the tripped position with the links 51, 47 collapsing to permit the lever 33 (FIG. 2) to move in a clockwise direction to the tripped-open position. As can be understood with reference to FIGS. 3, 4, 7 and 8, movement of the trip shaft 69 to the tripped position permits the members 59, 51, 47 to move to the tripped position wherein the roller 55 and link 47 no longer restrain the lever 33 in the closed position, and the springs 177, 180 (FIG. 2) operate to move the jackshaft 35 and the three contact arms 25 to the tripped-open position illustrated in FIG. 8.

The circuit breaker is trip free in that an operator cannot manually restrain the breaker in a closed position when an overload occurs in any of the pole units.

With the circuit breaker in the tripped-open position seen in FIG. 8, the breaker is reset and the closing springs 97 are charged by operation of the manual operating means 105 (FIGS. 1, 5 and 6). In order to reset the circuit breaker and charge the closing springs, an operator operates the handle 125 about the pivot 115 through an angle of slightly more than 90.degree. from the position seen in FIG. 5 to the position seen in FIG. 6. Referring to FIG. 5, it will be seen that the spring 133 biases the hook member 129 in a clockwise direction about the pivot 131, which movement is restrained by the engagement of the member 129 with part of the crankshaft 87. During the initial part of the charging and resetting movement of the manual operating means 105, the hook member 129 moves in a clockwise direction about the pivot pin 131 and the hook pin 135 moves into the notch 137 of the crank 107 under the bias of the spring 133. Upon further movement of the manual operating means 105, the pin 135, engaging in the notch 137, pulls the crank 107 to rotate the crankshaft 87 in a counterclockwise direction from the position seen in FIG. 5 to the position seen in FIG. 6. As can be understood with reference to FIGS. 5 and 6, with the handle member 125, 113 mounted for pivotal movement about the fixed pivot 115, and with the hook member 129 mounted for pivotal movement about the pin 131 on the member 113, a movement of slightly more than 90.degree. of the member 113 will serve to rotate the crank 87 more than 180.degree.. During the operation of the manual operating means 105 from the position seen in FIG. 5 to the position seen in FIG. 6, the circuit breaker parts are operated from the position seen in FIG. 8 to the position seen in FIG. 2. As the crankshaft 87 moves counterclockwise (FIG. 8) the crankshaft reaches a point where the roller 55 rides off of the end of the cam and into the depression 174. When the roller 55 is free to move into the depression 174, the spring 64 (FIGS. 4 and 8) biases the latch 59 to a clockwise direction to move the latch 59 clockwise to the reset position pulling the links 51, 47 and the roller 55 to the reset position wherein the roller 55 is positioned in the depression 174 (FIG. 2). When the latch member 59 moves out of the notch 71 (FIG. 4) a spring 182 (FIG. 1) operates to rotate the trip shaft 69 in a clockwise direction from the position seen in FIG. 4 to the position seen in FIG. 3 whereupon the periphery of the trip shaft 69 again latches the latch member 59 to latch the parts in the reset position seen in FIG. 2. As the crankshaft 87 moves over the 180.degree. line from the position seen in FIG. 8, the springs 97 serve to bias the crankshaft 87 in a counterclockwise (FIG. 2) direction and the roller 85 engages the latch 138 to latch the crankshaft 87 in the charged position seen in FIG. 2. Because of frictional forces, the springs 97 take over after the crankshaft 87 moves through an angle of about 184.degree. from the FIG. 8 position. If the operator leaves go of the handle 125, the spring 117 will bias the handle 125 back to the initial position seen in FIG. 5. In the position seen in FIG. 2, the circuit breaker 5 is prepared for another closing operation by operation of the closing means 139 (FIGS. 11--13).

When the circuit breaker is in the contact-closed position with the stored-energy closing springs 97 discharged (FIG. 7), the spring-closing means 97 can be manually operated to the charged position seen in FIG. 9. As can be seen in FIG. 7, the closing cam 57 is provided with a cam surface 175 that serves to operate the contacts to the closed position seen in FIG. 7 upon counterclockwise movement of the cam 57 from the position seen in FIG. 2 to the position seen in FIG. 7. The cam 57 comprises a cam surface 185 that is continuous with the cam surface 175 and that extends from where the roller 55 engages the closing cam as seen in FIG. 7 around to the end of the cam surface 185 just at the edge where the depression 174 begins. This surface 185 has a fixed radius from the axis of the crankshaft 87 so that as the cam 57 is rotated in a counterclockwise direction from the position seen in FIG. 7 to the position seen in FIG. 9 the roller 155 will merely ride on the surface 185 without effecting movement of the link 47. The surface 185 serves to prop the roller 55 as the closing cam moves from the FIG. 7 to the FIG. 9 position to thereby permit operation of the crankshaft and charging of the closing springs 97 without affecting the closed position of the contacts. Thus, when it is desired to charge the closing springs 97 with the contacts in the closed position the manual operating means 105 (FIG. 5 and 6) is operated in the same manner hereinbefore described to rotate the crankshaft 87 in a counterclockwise direction. As can be understood with regard to FIGS. 7 and 9, as the cranks 93 move over the 184.degree. line from that seen in FIG. 7, the charged closing springs 97 will serve to bias the crankshaft 87 in a counterclockwise (FIG. 9) direction, and the latch 138 will engage the roller 85 to latch the crankshaft 87 in the charged position seen in FIG. 9.

With the parts shown in the contact-closed spring-charged position seen in FIG. 9, the following sequence of operations can upon the occurrence of an overload above a predetermined value, the trip means 179 (FIG. 1) will be automatically operated to rotate the trip shaft 69 from the latching position seen in FIG. 3 to the tripped position seen in FIG. 4. This releases the latch 59 permitting the latch 59 to rotate in a counterclockwise direction about the pin 63 permitting the links 51 and 47 to collapse thereby permitting the lever 33 and jackshaft 35 (FIG. 2) to be rotated in a clockwise direction to permit the movement of the contact arms 25 to the open position seen in FIG. 2. With the links 51, 47 collapsed, the resetting spring 64 will operate to, rotate the latch member 59 in a clockwise direction about the pivot 63 to the reset position seen in FIG. 3 drawing the roller 55 into the depression 174 in the cam 57. As the latch member 59 reaches the reset position the spring 182 will rotate the trip shaft 69 to the reset position seen in FIG. 3 to again latch the links 59, 51, 47 in the reset position. The parts at the end of this tripping operation will be in the position seen in FIG. 2 wherein the mechanism is reset and relatched and wherein the roller member 55 is in the depression 174 so that the parts are prepared for an immediate closing operating. Thus, at the expiration of the tripping operation, when the closing springs 97 are charged, an operator can immediately press the member 141 to move the latch 138 to the unlatching position in the same manner hereinbefore described to thereby release the roller 85 whereupon the circuit breaker will be operated from the position seen in FIG. 2 to the closed position seen in FIG. 7 in the same manner as was hereinbefore described. With the parts in the closed position seen in FIG. 7, if an overload above the predetermined value occurs in any of the pole units the trip means 179 (FIG. 1) will operate automatically to rotate the trip shaft 69 to effect a tripping operation in the same manner as was hereinbefore described whereupon the parts will move to the position seen in FIG. 8. With the parts in the position seen in FIG. 8, another operation of the manual operation means 105 will be required in order to charge the closing springs 97 to provide for a closing operation. Thus, when the circuit breaker is in the contact-closed spring-charged position seen in FIG. 9, the circuit breaker can be tripped and then closed and then tripped again in rapid sequence.

When the circuit breaker is in the contact-closed position, and the closing springs 97 are in the charged condition, the closing means 139 is automatically rendered ineffective so that depression of the closing member 141 will not move the latch 138 to the unlatching or releasing position. Thus, this interlock means provides that the charged closing springs 97 will not be discharged when the contacts are in the closed position, which discharging action could serve to damage parts. As can be understood with reference to FIGS. 7 and 13, when the circuit breaker is in the contact-closed position the link 157 positions the fulcrum member 161 at the right-hand end of the slot 163 (FIG. 13) where the member 161 is out of the way so that it will not act as a fulcrum on the lever 147 when the member 141 is depressed. Thus, when the closing member 141 is depressed to the position seen in FIG. 13, and the contacts are in the closed position, the pivot support pin 149 of the lever 147 will move to the right, and the top portion of the lever 147 is free to move to the right so that this depression will not serve to move the bellcrank lever 151 in a clockwise unlatching direction. As can be understood with reference to FIG. 13, the closing closed 141 is in the depressed position and the bellcrank 151 has not been pivoted clockwise so that the latch 138 has not been actuated to the releasing or unlatching position. Thus, the closing means 139 is automatically rendered ineffective such that when the closing member is depressed with the circuit breaker in the contact-closed position and the closing springs charged this depression will not release the closing latch 138. When it is observed that manual depression of the closing member 141 is rendered ineffective, the operator will be able to readily determine that the contacts are already in the closed position and the charged closing springs will not be discharged which discharging action could serve to damage the parts.

From the foregoing, it can be understood that there is provided by this invention an improved circuit breaker with improved means for supporting the parts of the breaker mechanism. The breaker housing comprises a base plate, a pair of sideplates and a pair of center plates. A crankshaft is rotatably supported on the center plates with a pair of springs at the opposite ends of the crankshaft on the outside of the center plates and a closing cam connected to the crankshaft within the center plates. Thus, the force reactions on the closing cam operate on two bearings on the center plates, and the symmetrically disposed closing springs, which serve to drive the crankshaft and operate the closing cam, operate on the bearings on the center plates. A latch roller on the closing cam serves to engage a latch member to latch the crankshaft in the spring-charged position. The trip shaft is supported primarily on a bearing that is mounted on the center plates, and the latch that engages the trip shaft is supported on one of the center plates to engage the trip shaft in proximity to the bearing support of the trip shaft, with the opposite end of the trip shaft being supported as an outrigger type support on one of the sideplates. The jackshaft, which drives the three contact arms, is supported on bearings supported on the sideplates, and open-sided bearings on the center plates. Thus, the jackshaft bears at four places on the housing structure, and the jackshaft can be readily assembled with the three operating levers welded thereto since the jackshaft can be moved into the open-sided bearings on the center plates during the assembly operation. The circuit breaker comprises a nonbrute-force-type interlock to prevent discharging of the charged stored-energy closing springs when the contacts are in the closed position. The closing means comprises lever members that are effective to release the crankshaft when the closing member is depressed with the contacts in the open position and that are rendered ineffective when the contacts are in the closed position so that if the closing member is depressed with the contacts in the closed position the charged stored-energy closing springs will not be released.

Claims

We claim as our invention:

1. A multipole circuit breaker comprising a housing structure, a circuit-breaker mechanism supported on said housing structure, said housing structure comprising a base plate and a pair of spaced generally parallel sideplates connected to said base plate, a pair of spaced generally parallel center plates connected to said base plate within the dimension between sideplates and supported in a generally parallel relationship with said sideplates, said circuit breaker mechanism comprising an elongated jackshaft common to all of said poles, each of said poles comprising a stationary contact and a movable contact, means operatively connecting each of said movable contacts with said jackshaft, bearing means on each of said sideplates and on each of said center plates supporting said jackshaft for pivotal movement about a fixed pivot, said bearing means on said center plates comprising a separate open-sided bearing on each of said center plates permitting movement of said jackshaft into said open-sided bearings in a direction normal to the direction of elongation of the axis of said jackshaft during the mounting operation of said jackshaft on said sideplates and center plates, each of said center plates having a crankshaft-receiving opening therein, a crankshaft extending through said crankshaft-receiving openings and being supported on said center plates for rotational movement, a closing cam on said crankshaft between said center plates, link means operatively connecting said closing cam with said jackshaft, spring means comprising a pair of closing springs supported on opposite sides of said pair of center plates, means connecting each of said closing springs to said crankshaft, means operable to rotate said crankshaft from a spring-discharged position to a spring-charged position to charge said spring means and when said spring means is charged to release said charged spring means whereupon said charged spring means discharges to rotate said crankshaft to said spring-discharged position, and said closing cam upon rotation of said crankshaft to said spring-discharged position operating through said link means and said jackshaft to move said movable contacts to the closed position.

2. A multipole circuit breaker according to claim 1, said crankshaft being operable from said spring-discharged position in one direction to said spring-charged position to charge said closing springs and to position said closing springs such that said charged closing springs bias said crankshaft in said one direction toward said spring-discharged position, latch means comprising a first latch on said closing cam and a second latch separate from said closing cam, said latch means latching said crankshaft in said spring-charged position, and means operable to release said latch means whereupon said closing springs discharge to rotate said crankshaft to said spring-discharged position.

3. A circuit breaker according to claim 1, each of said closing springs comprising a spring member supported at one end thereof on a fixed support and connected at the other end thereof to said crankshaft, said crankshaft being rotatable in one direction to said spring-charged position to move said other ends of said closing springs to thereby charge said closing springs, latch means automatically latching said crankshaft in said spring-charged position to thereby latch said closing springs in the charged condition, means for releasing said latch means, and upon release of said latch means said charged closing springs discharging to move said crankshaft in said one direction to said spring-discharged position.

4. A multipole circuit breaker according to claim 1, said circuit breaker comprising three pole units, a separate lever projection fixed to said jackshaft at each of said pole units, means operatively connecting each of said lever projections with the associated movable contact, means operatively connecting the lever projection of the center pole unit to said operating means, said pole units being disposed in a side-by-side relationship, the lever projection of the center pole unit being positioned within the dimension between said center plates, and each of the lever projections of the two outer pole units being positioned within a lateral dimension between a different one of said center plates and the associated sideplate.

5. A circuit breaker comprising a stationary contact, a movable contact, an operating mechanism comprising a linkage, stored-energy closing means, a closing cam, means operable to move said closing cam from a first position to a charged position to operate said stored-energy closing means from a discharged condition to a charged condition, said closing cam comprising a pair of twin cam members fixedly supported with relation to each other, a roller latch member supported on said closing cam between said twin cam members, a closing latch engaging said roller latch member to latch said closing cam in the charged position, and closing means operable to move said closing latch to release said roller latch member whereupon said charged stored-energy closing means discharges to move said closing cam to the closed position during which movement said closing cam operates through said linkage to thrust said movable contact into engagement with said stationary contact.

6. A circuit breaker according to claim 5, said closing cam comprising a cam surface, and said linkage comprising a roller member movable on said cam surface of said closing cam upon operative movement of said closing cam to operate through said linkage to thrust said movable contact into engagement with said stationary contact.

7. A circuit breaker comprising a pair of contacts operable between open and closed positions, stored energy closing means, charging means operable to charge said stored-energy closing means, latch means latching said stored-energy closing means in a charged condition, closing means comprising a closing member operable from an unactuated position to a closing position when said contacts are open and said stored-energy closing means is latched to release said latch means whereupon said stored-energy closing means discharges to close said contacts, said closing member being operable from said unactuated position to said closing position when said contacts are closed and said stored-energy means is latched, and means operating automatically when said contacts are closed and said stored-energy closing means is latched to render said operation of said closing member from said unactuated position to said closing position ineffective such that said operation of said closing member from said unactuated position to said closing position will not release said latch means.

8. A circuit breaker according to claim 7, a fulcrum member, means automatically moving said fulcrum member to an operative position when said contacts are opened and to an inoperative position when said contacts are closed, an elongated lever member pivotally supported intermediate the ends thereof on said closing member, when said contacts are open and said closing member is operated to the closing position said lever member engaging said fulcrum member at one end thereof and moving about said fulcrum member such that the other end thereof operates to release said latch means, and when said contacts are in the closed position said fulcrum member being in said inoperative position such that said lever member is not operated to release said latch means when said closing member is operated to the closing position.

9. A circuit breaker according to claim 8, and said closing member being supported for movement about a fixed pivot between said unactuated position and said closing position.

10. A circuit breaker according to claim 9, said latch means comprising a latch member latching said stored-energy closing means in the charged condition, a bellcrank lever supported on a fixed pivot, when said closing member is operated from said unactuated position to said closing position with said contacts in the open position said other end of said lever member engaging one leg of said bellcrank lever to pivot said bellcrank lever such that the other leg of said bellcrank lever engages said latch member to move said latch member to the unlatching position.