US 3806684 A
A circuit breaker comprising a mechanism for converting the basic hand-operated circuit breaker to a motor-operated circuit breaker, after assembly of the hand-operated circuit breaker. The conversion mechanism comprises a mechanical reciprocating portion which is open at the lower end so that it can slide over the crankshaft assembly with the closing spring crank and hand cam in position, to quickly and easily convert a hand operated breaker into a motor operated breaker.
Description (OCR text may contain errors)
United States Patent [1 1 [111 3,806,684 Hauser Apr. 23, 1974 MECHANISM FOR CONVERTING A 2,607,240 8/1952 Kesling 74/548 HAND OPERATED CIRCUIT BREAKER o 3,234,803 2/1966 Caswell et a1 335/76 X 2,627,364 2/1953 Schafler et al 287/52 R x A MOTOR-OPERATED CIRCUIT BREAKER Richard Hauser, Toms River, NJ.
Westinghouse Electric Corporation, Pittsburgh, Pa.
Filed: Aug. 4, 1972 Appl. No.: 277,953
U.S. Cl 200/153 SC, 74/548, 185/40, 335/76 Int. Cl. HOlh 3/30 Field of Search 200/153 SC, 153 G, 153 H; 74/548; 335/68, 76; 287/52 R; 185/40 Primary ExaminerRobert K. Schaefer Assistant Examiner-Robert A. Vanderhye Attorney, Agent, or Firm-H. G. Massung verting the basic hand-operated circuit breaker to a motor-operated circuit breaker, after assembly of the hand-operated circuit breaker. The conversion mechanism comprises a mechanical reciprocating portion which is open at the lower end so that it can slide over the crankshaft assembly with the closing spring crank and hand cam in position, to quickly and easily convert a hand operated breaker into a motor operated breaker.
6 Claims, 6 Drawing Figures I I wmmgmmamm 3805684 sum 1 [1F 4 W UAFR 23 m4 SHEET 2 BF 4 [III/11 ITIIIIIIIIII IIYZ PATENTEDhPR 2 3 m4 sum 3 OF 4 SHEET u or 4 WI'ENTHJ APR 23 mm BACKGROUND OF THE INVENTION This invention is concerned with low voltage circuit breakers and more particularly with the spring operated closing mechanism for such circuit breakers.
This invention is concerned with the low voltage circuit breakers of the type as described in U.S. Pat. No. 3,590,192 issued June 29, 1971 to Fred Bould et al, and assigned to the same assignee as the present application. In U.S. Pat. No. 3,590,192 there is disclosed a spring closing mechanism for closing the circuit breaker with manual means for charging the spring closing mechanism. This invention is also concerned with low voltage circuit breakers with motor operated spring closing means such as shown in U.S. Pat. No. 3,600,540 issued Aug. 17, 1971 to Fred Bould and assigned to the same assignee as the present application. Since, the reciprocating portion with ratcheting pawl is not needed on a hand operated breaker due to the one stroke hand closing and is only required on a motor operated breaker, it isadvantageousto make the reciprocating portion so that it can be easily added to or removed from the circuit breaker without disassembling the circuit breaker mechanism.
SUMMARY OF THE INVENTION A circuit breaker comprising a metallic housing structure and a circuit breaker mechanism supported on thehousing structure. The housing structure comprises a base plate and a pair of spaced generally parallel side plates 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 side plates. A crankshaft is supported on the center plate with a closing cam'supported on the crankshaft between the center plates. A pair of springs are connected to the crankshaft. at the opposite sides of the center plates, to provide stored energy means for clos- I ing the circuit breaker contacts. A jack shaft 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 side plates 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. A linkage that is supported on one side of the center plates engages a trip bar to latch the circuit breaker in the reset operating position. 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 moment and possible deflection of thetrip 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 jack shaft to close the contacts.
When the closing spring is charged and the closing cam is latched withthe circuit breaker contacts in the open position, the closing member is manually depressed to unlatch the closing latch to release the charged closing springs which then operate to close the contacts.
A reciprocating mechanism comprising a ratcheting pawl is provided to convert a hand operated circuit breaker to a motor operated circuit breaker. The lower partof the reciprocating mechanism is open so that it can be slid over the crank shaft assembly with the crank arm, the manual operating mechanism, and the closing spring in place. Thus a hand operated circuit breaker can be made into an electric motor operated circuit breaker without major disassembly of the circuit breaker operating mechanism.
When used as a motor operated breaker the circuit breaker comprises a motor drive structure. The motor drive structure comprises a main body motor part and a rotatable output shaft structure extending from the motor. The motor is supported on one-of the breaker sideplates and the end part of the output shaft structure is supported on a bearing support mounted on one of the center plates. Upon energization of the motor, a cam part on the output shaft rotates and operates against the reciprocating structure to advance the ratchet wheel to charge the closing springs.
In using the teachings of this invention, assembly of BRIEF DESCRIPTION OF THE DRAWINGS Further advantages of the present invention will be readily apparent upon reading the following description taken in conjunction with the drawings in which:
FIG. 1 is an end view with parts broken away and with the certain parts left'out for the purpose of clarity of a circuit breaker constructed in accordance with the principles of this invention;
FIG. 2 is a sectional view taken generally along the line IIII of FIG. I;
DESCRIPTION'OF THE PREFERRED EMBODIMENTS Referring now to the drawings, and FIGS. 1 and 2 in particular, there is shown a three pole circuit breaker 10 comprising a support structure or housing 12 and a circuit breaker structure 14. The circuit breaker structure 14 is supported on the housing structure 12. The housing structure 12 comprises a metallic base plate 11, a pair of spaced metallic'side plates 13, a pair of metallic center plates 17 and a back wall structure indicated generally at 19. The metallic sideplates 13 and the center plates 17 are physically secured to the base plate 11.
The circuit breaker structure 14 is a three-pole structure comprising a stationary contact 121 and a movable contact 123 for each pole. Each of the movable contacts 123 is supported on a conducting'contact arm 25 that is pivotally supported on a terminal conductor 27 by means ofa pivotal support 29. In each pole unit, a separate insulating connecting member 31 is pivotally connected at one end to the contact arm 25 and at the other end thereof to a lever 33 that is welded to a common jack shaft 35. The jack shaft 35 extends across all of the poles of the circuit breaker 10. There is a separate lever 33 for each pole unit welded to the common jack shaft 35. Only one of the contact structures is shown in FIG. 1. The contact structure forthe center pole and for the left-hand pole are deleted from the drawing in FIG. 1 for 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 The jack shaft 35 is supported for pivotal movement about its longitudinal axis. The connecting member 31, lever 33, and jack shaft 35 are part of the stored energy spring closing mechanism 39 that is operable to close the contacts 121 and 123. The mechanism 39 comprises a link 41 that is pivotally connected at one end thereof to the lever 33 of the center pole by means of a pin 43. The link 41 is pivotally connected at the other end thereof to a link 45 by means of pivot pins 47. A roller member 49 serves as a cam follower and is mounted on the pin 47 to cooperate with the closing cam 51. The link 45 is pivotally connected at the other end thereof to the latch member 53 by means of a pin 55. The latch member 53 is supported for pivotal movement about a fixed pivot pin 57 that is supported on the left-hand center plate 17. A tension spring 59 is connected to pin 55 to reset the linkage followinga tripping operation of the circuit breaker 10. The latch member 53 engages the periphery of a trip shaft 63 in proximity to a circuit portion of the shaft 63. The cutout portion of the shaft 63 is provided so that when the trip shaft 63 is rotated in a counterclockwise direction, the latch member 53 will be free to move in the cutout portion to the trip position- The trip shaft 63 is supported for pivotal movement about the longitudinal axis thereof.
A roller latch is rotatably supported on and between the twin plates of the closing cam 51. The closing cam 51 is fixedly secured to a crankshaft 71 that is rotatably supported on suitable bearings. A pair of crank arms 73 are fixedly mounted on the crankshaft 71. A ratchet member 75 is fixedly mounted on the crankshaft 71. The reciprocating pawl structure 20, which is the subject of the present invention, is supported on the crankshaft 71 and will be described in detail hereinafter. The tension spring 79 is operatively connected at the end of each of the crank arms 73. Each of the tension springs 79 is connected at the other end thereof to a rod 82 that is attached to the center plate 17. The manual operating mechanism indicator generally at'83 is provided for manually charging the closing springs 79. A latching member 85 is pivotally mounted on the pin 86 and biased in a clockwise direction to the latching position I clockwise movement.
The circuit breaker 10 is shown in FIG. 2 in the contact open position with the stored energy closing spring 79 in the charged condition. As is shown in FIG. 2, the spring support pins of the tension spring 79 are below a line between the center of the spring support rod, 82 and the center of the shaft 71 so that the charged tension springs 79 are operated to bias the crankshaft 71 in a counterclockwise direction. Counterclockwise movement of the crankshaft 71 is prevented by engagement of the latch member with the latch roller 67 that is mounted on the closing cam 51. The latch member 85 is operated to the unlatched position to close the circuit breaker in a manner described in detail in the above mentioned US. Pat. No. 3,590,192. When it is desired to close the breaker, the latch 85 is pivoted in a counterclockwise direction to thereby release the roller 67. When the roller 67 is re leased, the closing cam 51 and crankshaft 71 are free to rotate in a counterclockwise direction and the closing spring 79 operating on the crank arm 73 operates to rotate the crankshaft 71 in a counterclockwise direction as the spring 79 is discharged. During this movement, the closing cam 51 will force the roller 49 and the link 41 to the closed position. During closing, link 41 attached to lever 33 is forced in a counterclockwise direction to rotate the jack shaft 35 counterclockwise. Counterclockwise rotation of jack shaft 35 simultaneously moves the three contact arms 25 in a clockwise direction about the pivot 29 to the closed position. In the closed position, the engagement of the closing cam 51 with the roller 49 serves to prop the link 41 in the closed position to thereby maintain the jack shaft 35 and the contact 123 in the closed circuit position.
Operation of the circuit breaker 10 is described in detail in the above mentioned US. Pat. No. 3,590,l92 and US. Pat. No. 3,600,540.
Referring now to FIGS; 3, 4, 5 and 6, there is shown a reciprocating pawl structure20. The reciprocating pawl structure 20 comprises a pair of spaced plates 21 and 22 that straddle ratchet wheel 75 and a spacer pin 92 which extends between the plates 21 and 22. A bight portion 23 which extends generally parallel to the crankshaft 71 connects the plates 21 and 22. The reciprocating pawl structure 20 is mounted on the crankshaft 71 for movement relative to the crankshaft 71 about the longitudinal axis of the crankshaft 71. A driving pawl 24 is pivotally mounted on the reciprocating structure 20 between the twin plates 21 and 22 by means of a pin 126. A torsion spring 26 biases the pawl 24 in a counterclockwise direction about the pin 126 into engagement with the ratchet wheel 75. A tension spring member 127 biases the reciprocating pawlstructure 20 in a clockwise direction about the crankshaft 71. The lower part of plates 21 and 22 are opened so that they can slide over the crankshaft 71 with the closing spring 79, crank arm 73, and the closing cam 51 in place. This allows the'reciprocating pawl structure 20 to be easily added or removed from the circuit breaker 10 without major 'disassembly. With the addition of the reciprocating pawl structure 20 and the electric drive motor assembly 101, a hand operated circuit breaker can be quickly and easily converted, to an electric motor operated circuit breaker.
When required or when desired, an L-shaped bridging member 28 fits under the crankshaft 71 and attaches to plates 21 and 22 by suitable means, such as the connector 128 which extends laterally from the plate 21 generally parallel to the crankshaft 71 and a pivot pin (not shown) which passes through the opening 94 in the plate 22. Member 28 secures the reciprocating pawl assembly to shaft 71 so that the reciprocating pawl assembly 20 can move about the longitudinal axis of the shaft 71 but cannot move off of the shaft 71. A holding pawl 112 is pivotally mounted on one of the center plates 17 by means ofa pin 113. The holding pawl 112 is biased in a counterclockwise direction, by means of a torsion spring 125, into engagement with ratchet wheel 75.
When the reciprocating pawl assembly 20 is added to a hand operated breaker to convert it to a motor operated circuit breaker, a motor drive structure 101 must also be added to the circuit breaker to operate the reciprocating pawl structure 20. The motor drive structure 101 comprises a main bodymotor 131 and an output shaft structure 133. The output shaft structure 133 comprises an end portion 135 and a roller arm 137. A roller member 139 is rotatably mounted on the roller arm 137. The motor 131 is secured to the side plate 13.
As can be seen in FIGS. 3 and 5 the closing springs 79 are in the charged position with the closing latch 85 as shown in FIG. 2 engaging the roller 67 of the cam 51 to latch the crankshaft 71. Upon release of the latch 85 the spring 79 discharges rotating the crankshaft 71 approximately 180 to close the circuit breaker 10. Upon discharge of the closing spring 79, suitable limit switch means are actuated to energize the motor drive structure 101. Upon being energized, the output shaft structure 133 is rotated in a clockwise direction. Upon rotation of the output shaft structure 133 the roller 139 operating against the bight portion 23 of the reciprocating pawl structure 20 moves the reciprocating pawl strucuture 20 in a counterclockwise direction. During the counterclockwise movement of the reciprocating pawl structure 20, the driving pawl 24 operates against one of the teeth of the ratchet 75 to advance the ratchet 75 and the crankshaft 71. As the roller arm 137 moves 180 from the position seen in FIG. 5, the reciprocating pawl structure 20 will advance the ratchet 75 and the crankshaft 71 in a counterclockwise direction. As the roller arm 137 moves the remaining l80 of a 360 revolution, the spring 127 will return the reciprocating pawl structure 20 to the position seen in FIG. 5. The holding pawl 112 holds ratchet 74 and crankshaft 71 in the advanced position. Thus as the output structure 133 rotates the ratchet 75 is advanced by the driving pawl 24 and alternately held by the holding pawl 112 until the crankshaft 71 moves more than 180 to an overcenter position wherein the charged closing spring 79 biases the crankshaft 71 in a counterclockwise direction. The ratchet 75 and the crankshaft 71 become latched from closing by the latch member 85 which engages the roller 67 on the cam 51, that is fixed to the crankshaft 71. When the closing spring 79 reaches the fully charged position, the driving pawl 24 is adjacent a missing tooth portion 154 of ratchet 75 so that continued rotation of the motor will not rotate ratchet 75. The motor 131 can then be brought to a stop condition without damaging the parts and without putting undue force on the ratchet 75. When the ratchet wheel reaches the position shown in FIG. vf5, the motor drive structure 101 is automatically deenergized, by suitable limit switch means.
Utilizing the teaching of the present invention, a basic hand operated circuit breaker can be assembled and the reciprocating structure 20 and motor structure 101 can be added as required. The alternatives to doing this are to ship all breakers with the reciprocating pawl structure 20 and wasting it on hand operated breakers, or to have one assembly for hand operated breakers and another assembly for motor operated breakers. Either of these alternatives would be undesirable from a cost point of view. By supplying a reciprocating pawl structure 20 with the lower part open, it can be fit over the crankshaft assembly 71 after the breaker is assembled and a basic hand operated breaker can be quickly and easily made into an electric motor operated breaker. This invention also facilitates maintenance of the breaker 10, since if any portion of the reciprocating pawl structure 20 is damaged, the damaged component can be easily replaced without a major disassembly of the circuit breaker 10.
Since numerous changes may be made in the above described apparatus and different embodiments of the invention may be made without departing from the spirit and scope thereof, it is intended that all matter contained in the foregoing description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
1. A circuit breaker comprising a support structure, a circuit breaker mechanism supported on said support structure, said circuit breaker mechanism comprising a closing spring means and a motor drive structure operable to charge said closing spring means, said closing spring means comprising a crankshaft supported for rotation and a pair of closing springs connected to said crankshaft, a ratchet wheel connected to said crankshaft, a reciprocating pawl structure mounted on said crankshaft for movement relative to said crankshaft, said reciprocating pawl structure comprising a first plate, a second plate spaced from said first plate and generally parallel thereto, a bight portion connecting said first plate and said second plate, a spacer separating and positioning said first plate and said second plate, a pawl disposed between said first plate andsaid second plate, a pin for supporting said pawl disposed between said first plate and said second plate and partially extending beyond said first plate, a torsion spring disposed around the portion of said pin extending beyond said first plate and engaging said first plate and said pawl when said reciprocating pawl structure is in place in said breaker and the movement of said torsion spring being restricted entirely by said first plate when said ratchet and pawl structure is removed from said breaker thereby limiting the rotation of said pawl when said ratchet and pawl structure is removed from said breaker, an opening in said reciprocating pawl structure through which said crankshaft extends, said opening for receiving said crankshaft being unclosed on at least one side to permit the reciprocating pawl structure to' be positioned onto said crankshaft after said crankshaft is in the final assembled position, holding means to hold said reciprocating pawl structure to said crankshaft, said motor drive structure comprising a main body motor part and a rotatable output shaft structure extending from said main body motor part,
said rotatable output shaft structure comprising an end part and an intermediate part, said intermediate part being intermediate said end part and said main body motor, support means supporting said motor drive structure on said support structure, means for energization of said motor drive structure to rotate said output shaft and cause said intermediate part to operate against said reciprocating pawl structure to advance said ratchet wheel to rotate said crankshaft to charge said closing spring means.
2. A circuit breaker as claimed in claim 1 wherein said intermediate part of said rotatable output shaft structure comprises an operating arm movable upon rotation of said output shaft through a first portion of a 360 rotation of said output shaft structure to move said reciprocating pawl structure against a tooth of said ratchet wheel to advance said ratchet wheel, and spring means operating to return said reciprocating pawl structure to a position where said reciprocating pawl structure is adjacent another tooth of said ratchet wheel during a second portion of said 360 revolution of said output shaft structure.
3. A circuit breaker as claimed in claim 1 wherein said intermediate part of said output shaft structure comprises a roller arm operable against said reciprocating pawl structure upon rotation of said output shaft structure.
4. A circuit breaker as claimed in claim 1 including holding means to prevent said reciprocating pawl structure from being removed from said crankshaft, said holding means being attached to said first plate and said second plate.
5. A circuit breaker as claimed in claim 4 wherein said holding means comprises a flat L-shaped portion, the bottom of said L-shaped portion being attached to said first plate and the top of said L-shaped portions being attached to said second plate.
6. A circuit breaker as claimed in claim 5 including spring biasing means to restrict the movement of said reciprocating pawl structure.