Stored energy system for breaker operating mechanism

Abstract

An operating mechanism for manipulating an operating handle of a circuit breaker is provided. The operating mechanism includes a holder assembly being configured, dimensioned and positioned to receive a portion of the operating handle where the holder assembly is capable of movement between a first position and a second position wherein the first position corresponds to a closed position of the handle and the second position corresponds to an open position of the handle. The operating mechanism further includes a drive plate being movably mounted to a support structure of the operating mechanism. The drive plate is coupled to the holder assembly. The operating mechanism also includes an energy storage mechanism for assuming a plurality of states, each state having a prescribed amount of energy stored in the energy storage mechanism. When the energy stored in the energy storage mechanism is released it provides an urging force to the drive plate causing the holder assembly to travel in the range defined by the first position to the second position.

Description

TECHNICAL FIELD

[0002] This invention relates to a method and apparatus for storing energy in a circuit breaker.

BACKGROUND OF INVENTION

[0003] Electric circuit breakers are generally used to disengage an electrical system under certain operating conditions. Therefore, it is required to provide a mechanism whereby a quantum of stored energy, utilized in opening, closing and resetting the circuit breaker after trip, is capable of being conveniently adjusted with a minimum of effort and without additional or special tools, in the field or in the manufacturing process. Conventional systems use a portion of stored energy to close the circuit breaker or circuit interrupter mechanism. This energy is wasted in overcoming resistance presented by components used in charging systems.

[0004] It is desired to provide a mechanism that minimizes the stored energy required for opening, closing, and resetting the breaker mechanism, as well as reducing the operational time to achieve quick closing of breaker (within 50 ms), using minimum signal power and with high reliability, thus optimizing the mechanism size, and cost.

SUMMARY OF INVENTION

[0005] An operating mechanism for a circuit breaker is provided. The operating mechanism includes a holder assembly being configured, dimensioned and positioned to receive a portion of an operating handle of the circuit breaker where the holder assembly is capable of movement between a first position and a second position wherein the first position corresponds to a closed position of the handle and the second position corresponds to an open position of the handle.

[0006] The operating mechanism further includes a drive plate being movably mounted to a support structure of the operating mechanism where the drive plate is being coupled to the holder assembly. The operating mechanism also includes an energy storage mechanism for assuming a plurality of states, each state having a prescribed amount of energy stored in the energy storage mechanism, the energy storage mechanism providing an urging force to the drive plate when the holder assembly is in the second position and the urging force causing the holder assembly to travel from the first position to the second position.

BRIEF DESCRIPTION OF DRAWINGS

[0007] FIG. 1 is an exploded three-dimensional view of the energy storage mechanism of the present invention;

[0008] FIG. 2 is a view of the auxiliary spring guide of the energy storage mechanism of FIG. 1;

[0009] FIG. 3 is a view of the main spring guide of the energy storage mechanism of FIG. 1;

[0010] FIG. 4 is a view of the assembled energy storage mechanism of FIG. 1;

[0011] FIG. 5 is a view of the assembled energy storage mechanism of FIG. 1 showing the movement of the auxiliary spring guide relative to the main spring guide and the assembled energy storage mechanism engaged to a side plate pin;

[0012] FIG. 6 is a more detailed view of a segment of the assembled energy storage mechanism of FIG. 5 showing the assembled energy storage mechanism engaged to a drive plate pin;

[0013] FIG. 7 is a three dimensional view of the energy storage mechanism of FIG. 1 including a second spring, coaxial with the main spring of FIG. 1;

[0014] FIG. 8 is a view of the locking member of the energy storage mechanism of FIG. 1;

[0015] FIG. 9 is a side view of the circuit breaker motor operator of the present invention in the CLOSED position;

[0016] FIG. 10 is a side view of the circuit breaker motor operator of FIG. 9 passing from the closed position of FIG. 9 to the OPEN position;

[0017] FIG. 11 is a side view of the circuit breaker motor operator of FIG. 9 passing from the closed position of FIG. 9 to the OPEN position;

[0018] FIG. 12 is a side view of the circuit breaker motor operator of FIG. 9 passing from the closed position of FIG. 9 to the OPEN position;

[0019] FIG. 13 is a side view of the circuit breaker motor operator of FIG. 9 in the OPEN position;

[0020] FIG. 14 is a first three dimensional view of the circuit breaker motor operator of FIG. 9;

[0021] FIG. 15 is a second three dimensional view of the circuit breaker motor operator of FIG. 9;

[0022] FIG. 16 is a third three dimensional view of the circuit breaker motor operator of FIG. 9;

[0023] FIG. 17 is a view of the cam of the circuit breaker motor operator of FIG. 9;

[0024] FIG. 18 is a view of the drive plate of the circuit breaker motor operator of FIG. 9;

[0025] FIG. 19 is a view of the latch plate of the circuit breaker motor operator of FIG. 9;

[0026] FIG. 20 is a view of the first latch link of the circuit breaker motor operator of FIG. 9;

[0027] FIG. 21 is a view of the second latch link of the circuit breaker motor operator of FIG. 9;

[0028] FIG. 22 is a view of the connection of the first and second latch links of the circuit breaker motor operator of FIG. 9;

[0029] FIG. 23 is a three dimensional view of the circuit breaker motor operator of FIG. 9 including the motor drive assembly;

[0030] FIG. 24 is a three dimensional view of the circuit breaker motor operator of FIG. 9, excluding a side plate;

[0031] FIG. 25 is a view of the ratcheting mechanism of the motor drive assembly of the circuit breaker motor operator of FIG. 9; and

[0032] FIG. 26 is a force and moment diagram of the circuit breaker motor operator of FIG. 9.

DETAILED DESCRIPTION

[0033] Referring to FIG. 1, an energy storage mechanism is shown generally at 300. Energy storage mechanism 300 comprises a main spring guide 304 (seen also in FIG. 3), a generally flat, bar-like fixture having a first closed slot 312 and a second closed slot 314 therein. Main spring guide 304 includes a semi-circular receptacle 320 at one end thereof and an open slot 316 at the opposing end. Main spring guide 304 includes a pair of flanges 318 extending outward a distance “h” (FIG. 3) from a pair of fork-like members 338 at the end of main spring guide 304 containing open slot 316. Fork-like members 338 are generally in the plane of main spring guide 304. Energy storage mechanism 300 further comprises an auxiliary spring guide 308. Auxiliary spring guide 308 (seen also in FIG. 2) is a generally flat fixture having a first frame member 330 and a second frame member 332 generally parallel to one another and joined by way of a base member 336. A beam member 326 extends generally perpendicular from first frame member 330 in the plane of auxiliary spring guide 308 nearly to second frame member 332 so as to create a clearance 340 (as seen in FIG. 2) between the end of beam member 326 and second frame member 332. Clearance 340 (as seen in FIG. 2) allows beam member 326, and thus auxiliary spring guide 308, to engage main spring guide 304 at second closed slot 314. Beam member 326, first frame member 330, second frame member 332 and base member 336 are placed into an aperture 334.

[0034] A tongue 328 extends from base member 336 into aperture 334. Tongue 328 is operative to receive an auxiliary spring 306, having a spring constant of ka, whereby auxiliary spring 306 is retained within aperture 334. The combination of auxiliary spring 306, retained within aperture 334, and auxiliary spring guide 308 is coupled to main spring guide 304 in such a manner that beam member 326 is engaged with, and allowed to move along the length of second closed slot 314. Auxiliary spring guide 308 is thereby allowed to move relative to main spring guide 304 by the application of a force to base member 336 of auxiliary spring guide 308. Auxiliary spring 306 is thus retained simultaneously within open slot 316 by fork-like members 338 and in aperture 334 by first frame member 330 and second frame member 332.

[0035] Energy storage mechanism 300 further comprises a main spring 302 having a spring constant km. Main spring guide 304, along with auxiliary spring guide 308 and auxiliary spring 306 engaged thereto, is positioned within the interior part of main spring 302 such that one end of main spring 302 abuts flanges 318. A locking pin 310 (FIG. 7) is passed through first closed slot 312 such that the opposing end of main spring 302 abuts locking pin 310 so as to capture and lock main spring 302 between locking pin 310 and flanges 318. As seen in FIG. 4, the assembled arrangement of main spring 302, main spring guide 304, auxiliary spring 306, auxiliary spring guide 308 and locking pin 310 form a cooperative mechanical unit. In the interest of clarity in the description of energy storage mechanism 300 in FIGS. 1 and 4, reference is made to FIGS. 2 and 3 showing auxiliary spring guide 308 and the main spring guide 304 respectively.

[0036] Reference is now made to FIGS. 5 and 6. FIG. 5 depicts the assembled energy storage mechanism 300. A side plate pin 418, affixed to a side plate (not shown), is retained within receptacle 320 so as to allow energy storage mechanism 300 to rotate about a spring assembly axis 322. In FIG. 6, a drive plate pin 406, affixed to a drive plate (not shown), is retained against auxiliary spring guide 308 and between fork-like members 338 in the end of main spring guide 304 containing open slot 316. Drive plate pin 406 is so retained in open slot 316 at an initial displacement “D” with respect to the ends of flanges 318. Thus, as seen in FIGS. 5 and 6, the assembled energy storage mechanism 300 is captured between side plate pin 418, drive plate pin 406, receptacle 320 and open slot 316.

[0037] Energy storage mechanism 300 is held firmly therebetween due to the force of auxiliary spring 306 acting against auxiliary spring guide 308, against drive plate pin 406, against main spring guide 304 and against side plate pin 418. As seen in FIG. 5, auxiliary spring guide 308 is operative to move independent of main spring 302 over a distance “L” relative to main spring guide 304 by the application of a force acting along a line 342 in FIG. 6. When auxiliary spring guide 308 has traversed the distance “L,” side plate pin 418 comes clear of receptacle 320 and energy storage mechanism 300 may be disengaged from side plate pin 418 and drive plate pin 406. As best understood from FIGS. 5 and 6, the spring constant, ka, for auxiliary spring 306 is sufficient to firmly retain the assembled energy storage mechanism 300 between side plate pin 418 and drive plate pin 406, but also such that only a minimal amount of effort is required to compress auxiliary spring 306 and allow auxiliary spring guide 308 to move the distance “L.” This allows energy storage mechanism 300 to be easily removed by hand from between side plate pin 418 and drive plate pin 406.

[0038] Referring now to FIG. 7, a coaxial spring 324, having a spring constant kc and aligned coaxially with main spring 302, is shown. Coaxial spring 324 may be engaged to main spring guide 304 between flanges 318 and locking pin 310 (not shown) in the same manner depicted in FIG. 4 for main spring 302, thus providing energy storage mechanism 300 with a total spring constant of kT=km+kc. Flanges 318 extend a distance “h” sufficient to accommodate main spring 302 and coaxial spring 324. Thus, energy storage mechanism 300 of the present invention is a modular unit that can be easily removed and replaced in the field or in the factory with a new or additional main spring 302. This allows for varying the amount of energy that can be stored in energy storage mechanism 300 without the need for special or additional tools.

[0039] Referring now to FIGS. 9-14, a circuit breaker (MCCB) is shown generally at 100. Circuit breaker 100 includes a circuit breaker handle 100 extending therefrom is coupled to a set of circuit breaker contacts (not shown). The components of the circuit breaker motor operator of the present invention are shown in FIGS. 9-14 generally at 200. Motor operator 200 generally comprises a holder, such as a carriage 202 coupled to circuit breaker handle 102, energy storage mechanism 300, as described above, and a mechanical linkage system 400. Mechanical linkage system 400 is connected to energy storage mechanism 300, carriage 202 and a motor drive assembly 500 (FIG. 24). Carriage 202, energy storage mechanism 300 and mechanical linkage system 400 act as a cooperative mechanical unit responsive to the action of motor drive assembly 500 and circuit breaker handle 102 to assume a plurality of configurations. In particular, the action of motor operator 200 is operative to disengage or reengage the set of circuit breaker contacts coupled to circuit breaker handle 102. Disengagement (i.e., opening) of the set of circuit breaker contacts interrupts the flow of electrical current through circuit breaker 100. Reengagement (i.e., closing) of the circuit breaker contacts allows electrical current to flow through the circuit breaker 100.

[0040] Referring to FIG. 8, in conjunction with FIGS. 15, 16 and 17, mechanical linkage system 400 comprises a pair of side plates 416 held substantially parallel to one another by a set of braces 602, 604 and connected to circuit breaker 100. A pair of drive plates 402 (FIG. 18) are positioned interior, and substantially parallel to the pair of side plates 416. Drive plates 402 are connected to one another by way of, and are rotatable about, a drive plate axis 408. Drive plate axis 408 is connected to the pair of side plates 416. The pair of drive plates 402 include a drive plate pin 406 connected therebetween and engaged to energy storage mechanism 300 at open slot 316 of main spring guide 304. A connecting rod 414 connects the pair of drive plates 402 and is rotatably connected to carriage 202 at axis 210.

[0041] A cam 420, rotatable on a cam shaft 422, includes a first cam surface 424 and a second cam surface 426 (FIG. 17). Cam 420 is, in general, of a nautilus shape wherein second cam surface 426 is a concavely arced surface and first cam surface 424 is a convexly arced surface. Cam shaft 422 passes through a slot 404 in each of the pair of drive plates 402 and is supported by the pair of side plates 416. Mechanical linkage system 400 minimizes the stored energy required for closing the breaker mechanism and reduces the closing time, thereby optimizing the mechanism size and cost. Cam shaft 422 is further connected to motor drive assembly 500 (FIGS. 24 and 25) from which cam 420 is driven in rotation.

[0042] Carriage 202 is connected to drive plate 402 by way of the connecting rod 414 of axis 210 and is rotatable thereabout. Carriage 202 comprises a set of retaining springs 204, a first retaining bar 206 and a second retaining bar 208. Retaining springs 204, disposed within carriage 202 and acting against first retaining bar 206, retain circuit breaker handle 102 firmly between first retaining bar 206 and second retaining bar 208. Carriage 202 is allowed to move laterally with respect to side plates 416 by way of first retaining bar 206 coupled to a slot 214 in each of side plates 416. Carriage 202 moves back and forth along slots 214 to toggle circuit breaker handle 102 back and forth between the position of FIG. 9 and that of FIG. 13.

[0043] In FIG. 9, circuit breaker 100 is in the closed position (i.e., electrical contacts closed) and no energy is stored in main spring 302. Motor operator 200 operates to move circuit breaker handle 102 between the closed position of FIG. 9 and the open position (i.e., electrical contacts open) of FIG. 13. In addition, when circuit breaker 100 trips due for example to an overcurrent condition in an associated electrical system, motor operator 200 operates to reset an operating mechanism (not shown) within circuit breaker 100 by moving the handle to the open position of FIG. 13.

[0044] To move the handle from the closed position of FIG. 9 to the open position of FIG. 13, motor drive assembly 500 rotates cam 420 clockwise as viewed on cam shaft 422 such that mechanical linkage system 400 is sequentially and continuously driven through the configurations of FIGS. 10, 11 and 12. As best seen in FIG. 10, cam 420 rotates clockwise about cam shaft 422. Drive plates 402 are allowed to move due to slot 404 in drive plates 402. Roller 444 on roller axis 410 moves along first cam surface 424 of cam 420. The counterclockwise rotation of drive plates 402 drives drive plate pin 406 along open slot 316 thereby compressing main spring 302 and storing energy therein. Energy storage mechanism 300 rotates clockwise about spring assembly axis 322 and side plate pin 418. Latch plate 430, abutting brace 604, remains fixed with respect to side plates 416.

[0045] Referring now to FIG. 11, drive plate 402 rotates further counterclockwise causing drive plate pin 406 to further compress main spring 302. Cam 420 continues to rotate clockwise. Rolling pin 446 moves from second concave surface 436 of latch plate 430 partially to first concave surface 434 and latch plate 430 rotates clockwise away from brace 604. Drive plate pin 406 compresses main spring 302 further along open slot 316.

[0046] In FIG. 12, latch plate 430 rotates clockwise until rolling pin 446 rests fully within first concave surface 434. Roller 444 remains in intimate contact with first cam surface 424 as cam 420 continues to turn in the clockwise direction. In FIG. 13, cam 420 has completed its clockwise rotation and roller 444 is disengaged from cam 420. Rolling pin 446 remains in contact with first concave surface 434 of latch plate 430.

[0047] Mechanical linkage system 400 thence comes to rest in the configuration of FIG. 13. In proceeding from the configuration of FIG. 9 to that of FIG. 13, main spring 302 is compressed a distance “x” by drive plate pin 406 due to counterclockwise rotation of drive plates 402 about drive plate axis 408. The compression of main spring 302 thus stores energy in main spring 302 according to the equation E=½km×2 where x is the displacement of main spring 302. Motor operator 200, energy storage mechanism 300 and mechanical linkage system 400 are held in the stable position of FIG. 13 by first latch link 442, second latch link 450 and latch plate 430. The positioning of first latch link 442 and second latch link 450 with respect to one another and with respect to latch plate 430 and cam 420 is such as to prevent the expansion of the compressed main spring 302, and thus to prevent the release of the energy stored therein. Referring to FIGS. 20-22, a pair of first latch links 442 are coupled to a pair of second latch links 450, about a link axis 412. Second latch link 450 is also rotatable about cam shaft 422. First latch links 442 and second latch links 450 are interior to and parallel with drive plates 402. A roller 444 is coupled to a roller axis 410 connecting first latch links 442 to drive plate 402. Roller 444 is rotatable about roller axis 410. Roller axis 410 is connected to drive plates 402 and roller 444 abuts, and is in intimate contact with, second cam surface 426 of cam 420. A brace 456 connects the pair of second latch links 450. An energy release mechanism, such as a latch plate 430, is rotatable about drive plate axis 408 and is in intimate contact with a rolling pin 446 rotatable about the link axis 412. Rolling pin 446 moves along a first concave surface 434 and a second concave surface 436 of latch plate 430. First concave surface 434 and second concave surface 436 of latch plate 430 are arc-like, recessed segments along the perimeter of latch plate 430 operative to receive rolling pin 446 and allow rolling pin 446 to be seated therein as latch plate 430 rotates about drive plate axis 408. Latch plate 430 includes a releasing lever 458 to which a force may be applied to rotate latch plate 430 about drive plate axis 408. In FIG. 9, latch plate 430 is also in contact with the brace 604.

[0048] As seen in FIG. 26, this is accomplished due to the fact that although there is a force acting along the line 462 caused by the compressed main spring 302, which tends to rotate drive plates 402 and first latch link 442 clockwise about drive plate axis 408, cam shaft 422 is fixed with respect to side plates 416 which are in turn affixed to circuit breaker 100. Thus, in the configuration FIG. 13 first latch link 442 and second latch line 450 form a rigid linkage. There is a tendency for the linkage of first latch link 442 and second latch link 450 to rotate about link axis 412 and collapse. However, this is prevented by a force acting along line 470 countering the force acting along line 468. The reaction force acting along line 472 at the cam shaft counters the moment caused by the spring force acting along line 462. Thus forces and moments acting upon motor operator 200 in the configuration of FIG. 13 are balanced and no rotation of mechanical linkage system 400 may be had.

[0049] In FIG. 13, circuit breaker 100 is in the open position. To proceed from the configuration of FIG. 13 and return to the configuration of FIG. 9 (i.e., electrical contacts closed), a force is applied to latch plate 430 on latch plate lever 458 at 460. The application of this force acts so as to rotate latch plate 430 counterclockwise about drive plate axis 408 and allow rolling pin 446 to move from first concave surface 434 as in FIG. 13 to second concave surface 436 as in FIG. 9. This action releases the energy stored in main spring 302 and the force acting on drive plate pin 406 causes drive plate 402 to rotate clockwise about drive plate axis 408. The clockwise rotation of drive plate 402 applies a force to circuit breaker handle 102 at second retaining bar 208 throwing circuit breaker handle 102 leftward, with main spring 302, latch plate 430 and mechanical linkage system 400 coming to rest in the position of FIG. 9.

[0050] Referring to FIG. 25, motor drive assembly 500 is shown engaged to motor operator 200, energy storage mechanism 300 and mechanical linkage system 400.

[0051] Motor drive assembly 500 comprises a motor 502 geared to a gear train 504. Gear train 504 comprises a plurality of gears 506, 508, 510, 512, 514. One of the gears 514 of gear train 504 is rotatable about an axis 526 and is connected to a disc 516 at the axis 516. Disc 516 is rotatable about axis 526. However, axis 526 is displaced from the center of disc 516. Thus, when disc 516 rotates due to the action of motor 502 and gear train 504, disc 516 acts in a cam-like manner providing eccentric rotation of disc 516 about axis 526.

[0052] Motor drive assembly 500 further comprises a unidirectional bearing 522 coupled to cam shaft 422 and a charging plate 520 connected to a ratchet lever 518. A roller 530 is rotatably connected to one end of ratchet lever 518 and rests against disc 516 (FIG. 26). Thus, as disc 516 rotates about axis 526, ratchet lever 518 toggles back and forth as seen at 528 in FIG. 26. This back and forth action ratchets the unidirectional bearing 522 a prescribed angular displacement, 2, about the cam shaft 422 which in turn ratchets cam 420 by a like angular displacement. Referring to FIG. 24, motor drive assembly 500 further comprises a manual handle 524 coupled to unidirectional bearing 522 whereby unidirectional bearing 522, and thus cam 420, may be manually ratcheted by repeatedly depressing manual handle 524.

[0053] While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. An operating mechanism for manipulating an operating handle of a circuit interruption mechanism, comprising: a mechanical linkage system coupled to an energy storage mechanism, said energy storage mechanism assuming a plurality of states, each state having a prescribed amount of energy stored in said energy storage mechanism, said energy storage mechanism providing an urging force to said mechanical linkage system, said mechanical linkage system being coupled to a carriage assembly, said mechanical linkage system being adapted to receive a driving force from a recharging cam to drive said energy storage mechanism from a first state of said plurality of states to a second state of said plurality of states; a release mechanism for disengaging said recharging cam from said mechanical linkage system when said energy storage mechanism is driven from said first state of said plurality of states to said second state; and an energy release mechanism coupled to said mechanical linkage system for releasing said energy stored in said energy storage mechanism.

2. An operating mechanism for manipulating an operating handle of a circuit interruption mechanism, comprising: a recharging cam being adapted to receive a driving force and rotate upon receipt of said driving force; a drive plate being rotatably mounted to said mechanism, said recharging cam and said drive plate being adapted to rotate said drive plate as said recharging cam is rotated by said driving force; an energy storage mechanism being compressed by said drive plate as said drive plate is rotated by said recharging cam; a linear carriage coupled to said drive plate, said linear carriage manipulating said operating handle of said circuit interruption mechanism when said energy storage mechanism is released from its compressed state; and a means for disengaging said recharging cam from said drive plate when said energy storage mechanism is compressed.

3. The operating mechanism as in claim 2, wherein said drive plate is latched into a position corresponding to a charged state of said energy storage mechanism, said drive plate being latched by a latch plate and latch links.

4. A system for manipulating an operating handle of a circuit interruption mechanism, comprising: a recharging cam being configured to by driven by a device; a drive plate being rotatably mounted to said system, said recharging cam rotating said drive plate as said recharging cam is being driven by said device; a spring being compressed by said drive plate as said drive plate is rotated into a latching position by said recharging cam; a linear carriage coupled to said drive plate, said linear carriage being movably mounted to said system and manipulating said operating handle of said circuit interruption mechanism; a means for disengaging said recharging cam when said drive plate is in said latching position; and a means for releasing said drive plate from said latching position.

5. The system as in claim 4, wherein said operating handle of said circuit interruption mechanism is manipulated when said drive plate is released from said latching position.

6. The system as in claim 4, further comprising: a means for re-engaging said recharging cam after said drive plate is released from said latching position and said spring is uncompressed.

7. The system as in claim 4, wherein said means for releasing said drive plate from said latching position is remotely activated by a solenoid.

8. The system as in claim 4, wherein said means for releasing said drive plate from said latching position is manually activated by a switch.

9. The operating system as in claim 1, wherein said carriage assembly further comprises: a carriage; a first retaining bar being rotatably mounted to said carriage; a second retaining bar being rotatably mounted to said carriage; and a plurality of springs being secured to said first retaining bar at one end and said carriage at the opposite end.