Abstract:
An energy storage mechanism for a circuit breaker motor operator is disclosed. The energy storage mechanism has a first elastic member; a first fixture having a plurality of slots therein, the first fixture positioned in the first elastic member; a second fixture having a plurality of members defining an aperture; a second elastic member engaged to the second fixture and positioned within the aperture; wherein the second fixture is engaged to the first fixture. A motor operator for a molded case circuit breaker is disclosed. The motor operator has an energy storage mechanism for assuming a plurality of states, each state having a prescribed amount of energy stored in the energy storage mechanism; a mechanical linkage system coupled to the energy storage mechanism and to the molded case circuit breaker; wherein the molded case circuit breaker is operative to assume a plurality of positions; wherein each position of the molded case circuit breaker is associated with a corresponding state of the energy storage mechanism; a motor drive assembly connected to the mechanical linkage system for driving the energy storage mechanism from a first state of the plurality of states to a second state of the plurality of states; and an energy release mechanism coupled to the mechanical linkage system for releasing the energy stored in the energy storage mechanism wherein the energy storage mechanism returns from the second state of the plurality of states to the first state of the plurality of states.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of Provisional Application No. 60/190,298 filed on Mar. 17, 2000, and Provisional Application No. 60/190,765 filed on Mar. 20, 2000, the contents of which are incorporated herein by reference thereto. 
    
    
     BACKGROUND OF THE INVENTION 
     It is known in the art to provide molded case circuit breakers for electrical systems. The circuit breaker is operative to disengage the electrical system under certain operating conditions. A motor operator allows the circuit breaker to be operated remotely and to be opened, closed or reset after tripping of the circuit breaker. It is advantageous 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, either in the field or in the factor during manufacturing of the circuit breaker. 
     BRIEF SUMMARY OF THE INVENTION 
     An energy storage mechanism for a circuit breaker motor operator is disclosed. The energy storage mechanism comprises a first elastic member; a first fixture having a plurality of slots therein, the first fixture positioned in the first elastic member; a second fixture having a plurality of members defining an aperture; a second elastic member engaged to the second fixture and positioned within the aperture; wherein the second fixture is engaged to the first fixture. A motor operator for a molded case circuit breaker is disclosed. The motor operator comprises an energy storage mechanism for assuming a plurality of states, each state having a prescribed amount of energy stored in the energy storage mechanism; a mechanical linkage system coupled to the energy storage mechanism and to the molded case circuit breaker; wherein the molded case circuit breaker is operative to assume a plurality of positions; wherein each position of the molded case circuit breaker is associated with a corresponding state of the energy storage mechanism; a motor drive assembly connected to the mechanical linkage system for driving the energy storage mechanism from a first state of the plurality of states to a second state of the plurality of states; and an energy release mechanism coupled to the mechanical linkage system for releasing the energy stored in the energy storage mechanism wherein the energy storage mechanism returns from the second state of the plurality of states to the first state of the plurality of states. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded three dimensional view of the energy storage mechanism of the present invention; 
     FIG. 2 is a view of the auxiliary spring guide of the energy storage mechanism of FIG. 1; 
     FIG. 3 is a view of the main spring guide of the energy storage mechanism of FIG. 1; 
     FIG. 4 is a view of the assembled energy storage mechanism of FIG. 1; 
     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; 
     FIG. 5A 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; 
     FIG. 6 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; 
     FIG. 7 is a view of the locking member of the energy storage mechanism of FIG. 1; 
     FIG. 8 is a side view of the circuit breaker motor operator of the present invention in the CLOSED position; 
     FIG. 9 is a side view of the circuit breaker motor operator of FIG. 8 passing from the closed position of FIG. 8 to the OPEN position; 
     FIG. 10 is a side view of the circuit breaker motor operator of FIG. 8 passing from the closed position of FIG. 8 to the OPEN position; 
     FIG. 11 is a side view of the circuit breaker motor operator of FIG. 8 passing from the closed position of FIG. 8 to the OPEN position; 
     FIG. 12 is a side view of the circuit breaker motor operator of FIG. 8 in the OPEN position; 
     FIG. 13A is a first three dimensional view of the circuit breaker motor operator of FIG. 8; 
     FIG. 13B is s second three dimensional view of the circuit breaker motor operator of FIG. 8; 
     FIG. 13C is a third three dimensional view of the circuit breaker motor operator of FIG. 8; 
     FIG. 14 is a view of the cam of the circuit breaker motor operator of FIG. 8; 
     FIG. 15 is a view of the drive plate of the circuit breaker motor operator of FIG. 8; 
     FIG. 16 is a view of the latch plate of the circuit breaker motor operator of FIG. 8; 
     FIG. 17 is a view of the first latch link of the circuit breaker motor operator of FIG. 8; 
     FIG. 18 is a view of the second latch link of the circuit breaker motor operator of FIG. 8; 
     FIG. 19 is a view of the connection of the first and second latch links of the circuit breaker motor operator of FIG. 8; 
     FIG. 20 is a three dimensional view of the circuit breaker motor operator of FIG. 8 including the motor drive assembly; 
     FIG. 21 is a three dimensional view of the circuit breaker motor operator of FIG. 8, excluding a side plate; 
     FIG. 22 is a view of the ratcheting mechanism of the motor drive assembly of the circuit breaker motor operator of FIG. 8; and 
     FIG. 23 is a force and moment diagram of the circuit breaker motor operator of FIG.  8 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, an energy storage mechanism is shown generally at  300 . The 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. The main spring guide  304  includes a semi-circular receptacle  320  at one end thereof and an open slot  316  at the opposing end. The 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 the main spring guide  304  containing the open slot  316 . The pair of fork-like members  338  are generally in the plane of the main spring guide  304 . The energy storage mechanism  300  further comprises an auxiliary spring guide  308 . The 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 the first frame member  330  in the plane of the auxiliary spring guide  308  nearly to the second frame member  332  so as to create a clearance  340  between the end of the beam member  326  and the second frame member  332 . The clearance  340  allows the beam member  326 , and thus the auxiliary spring guide  308 , to engage the main spring guide  304  at the second closed slot  314 . The beam member  326 , the first frame member  330 , the second frame member  332  and the base member  336  into the aperture  334 . A tongue  328  extends from the base member  336  into the aperture  334 . The tongue  328  is operative to receive an auxiliary spring  306 , having a spring constant of k a , whereby the auxiliary spring  306  is retained within the aperture  334 . The combination of the auxiliary spring  306 , retained within the aperture  334 , and the auxiliary spring guide  308  is coupled to the main spring guide  304  in such a manner that the beam member  326  is engaged with, and allowed to move along the length of, the second closed slot  314 . The auxiliary spring guide  308  is thereby allowed to move relative to the main spring guide  304  by the application of a force to the base member  336  of the auxiliary spring guide  308 . The auxiliary spring  306  is thus retained simultaneously within the open slot  316  by the fork-like members  338  and the in aperture  334  by the first frame member  330  and second frame member  332 . The energy storage mechanism  300  further comprises a main spring  302  having a spring constant k m . The main spring guide  304 , along with the auxiliary spring guide  308  and the auxiliary spring  306  engaged thereto, is positioned within the interior part of the main spring  302  such that one end of the main spring  302  abuts the flanges  318 . A locking pin  310  (FIG. 7) is passed through the first closed slot  312  such that the opposing end of the main spring  302  abuts the locking pin  310  so as to capture and lock the main spring  302  between the locking pin  310  and the flanges  318 . As seen in FIG. 4 the assembled arrangement of the main spring  302 , the main spring guide  304 , the auxiliary spring  306 , the auxiliary spring guide  308  and the locking pin  310  form a cooperative mechanical unit. In the interest of clarity in the description of the energy storage mechanism  300  in FIGS. 1 and 4, reference is made to FIGS. 2 and 3 showing the auxiliary spring guide  308  and the main spring guide  304  respectively. 
     Reference is now made to FIGS. 5 and 5A. FIG. 5 depicts the assembled energy storage mechanism  300 . A side plate pin  418 , affixed to a side plate (not shown), is retained within the receptacle  320  so as to allow the energy storage mechanism  300  to rotate about a spring assembly axis  322 . In FIG. 5A, a drive plate pin  406 , affixed to a drive plate (not shown), is retained against the auxiliary spring guide  308  and between the fork-like members  338  in the end of the main spring guide  304  containing the open slot  316 . The drive plate pin  406  is so retained in the open slot  316  at an initial displacement “D” with respect to the ends of the flanges  318 . Thus, as seen in FIGS. 5 and 5A, the assembled energy storage mechanism  300  is captured between the side plate pin  418 , the drive plate pin  406 , the receptacle  320  and the open slot  316 . The energy storage mechanism  300  is held firmly therebetween due to the force of the auxiliary spring  306  acting against the auxiliary spring guide  308 , against the drive plate pin  406 , against the main spring guide  304  and against the side plate pin  418 . As seen in FIG. 5, the auxiliary spring guide  308  is operative to move independent of the main spring  302  over a distance “L” relative to the main spring guide  304  by the application of a force acting along the line  342  in FIG.  5 A. When the auxiliary spring guide  308  has traversed the distance “L,” the side plate pin  418  comes clear of the receptacle  320  and the energy storage mechanism  300  may be disengaged from the side plate pin  418  and the drive plate pin  406 . 
     As best understood from FIGS. 5 and 5A, the spring constant, k a , for the auxiliary spring  306  is sufficient to firmly retain the assembled energy storage mechanism  300  between the side plate pin  418  and the drive plate pin  406 , but also such that only a minimal amount of effort is required to compress the auxiliary spring  306  and allow the auxiliary spring guide  308  to move the distance “L.” This allows the energy storage mechanism  300  to be easily removed by hand from between the side plate pin  418  and the drive plate pin  406 . 
     Referring to FIG. 6, a coaxial spring  324 , having a spring constant k c  and aligned coaxial with the main spring  302 , is shown. The coaxial spring  324  may be engaged to the main spring guide  304  between the flanges  318  and the locking pin  310  (not shown) in the same manner depicted in FIG. 4 for the main spring  302 , thus providing the energy storage mechanism  300  with a total spring constant of k T =k m +k c . The flanges  318  extend a distance “h” sufficient to accommodate the main spring  302  and the coaxial spring  324 . 
     Thus, the 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 factor with a new or additional main spring  302 . This allows for varying the amount of energy that can be stored in the energy storage mechanism  300  without the need for special or additional tools. 
     Referring to FIGS. 8-13C, a molded case circuit breaker (MCCB) is shown generally at  100 . The molded case circuit breaker  100  includes a circuit breaker handle  102  extending therefrom which 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. 8-13C generally at  200 . The motor operator  200  generally comprises a holder, such as a slidable carriage  202  coupled to the circuit breaker handle  102 , the energy storage mechanism  300 , as described above, and a mechanical linkage system  400 . The mechanical linkage system  400  is connected to the energy storage mechanism  300 , the slidable carriage  202  and a motor drive assembly  500  (FIGS.  20  and  21 ). The slidable carriage  202 , the energy storage mechanism  300  and the mechanical linkage system  400  act as a cooperative mechanical unit responsive to the action of the motor drive assembly  500  and the circuit breaker handle  102  to assume a plurality of configurations. In particular, the action of the motor operator  200  is operative to disengage or reengage the set of circuit breaker contacts coupled to the circuit breaker handle  102 . Disengagement (i.e., opening) of the set of circuit breaker contacts interrupts the flow of electrical current through the molded case circuit breaker  100 , as is well known. Reengagement (i.e., closing) of the circuit breaker contacts allows electrical current to flow through the molded case circuit breaker  100 , as is well known. 
     More particularly in FIG. 8, in conjunction with FIGS. 13A,  13 B and  13 C, the 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 the molded case circuit breaker  100 . A pair of drive plates  402  (FIG. 15) are positioned interior, and substantially parallel to the pair of side plates  416 . The drive plates  402  are connected to one another by way of, and are rotatable about, a drive plate axis  408 . The 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 the energy storage mechanism  300  at the open slot  316  of the main spring guide  304 . A connecting rod  414  connects the pair of the drive plates  402  and is rotatably connected to the slidable carriage  202  at axis  210 . A cam  420 , rotatable on a cam shaft  422 , includes a first cam surface  424  and a second cam surface  426  (FIG.  14 ). The cam  420  is, in general, of a nautilus shape wherein the second cam surface  426  is a concavely arced surface and the first cam surface  424  is a convexly arced surface. The 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 . The cam shaft  422  is further connected to the motor drive assembly  500  (FIGS. 20 and 21) from which the cam  420  is driven in rotation. 
     A pair of first latch links  442  (FIG. 17) are coupled to a pair of second latch links  450  (FIG.  18 ), about a link axis  412  (FIG.  19 ). The second latch link  450  is also rotatable about the cam shaft  422 . The first latch links  442  and the second latch links  450  are interior to and parallel with the drive plates  402 . A roller  444  is coupled to a roller axis  410  connecting the first latch links  442  to the drive plate  402 . The roller  444  is rotatable about the roller axis  410 . The roller axis  410  is connected to the drive plates  402  and the roller  444  abuts, and is in intimate contact with, the second cam surface  426  of the cam  420 . A brace  456  connects the pair of second latch links  450 . An energy release mechanism, such as a latch plate  430  (FIG.  16 ), is rotatable about the drive plate axis  408  and is in intimate contact with a rolling pin  446  rotatable about the link axis  412 . The rolling pin  446  moves along a first concave surface  434  and a second concave surface  436  (FIG. 16) of the latch plate  430 . The first concave surface  434  and the second concave surface  436  of the latch plate  430  are arc-like, recessed segments along the perimeter of the latch plate  430  operative to receive the rolling pin  446  and allow the rolling pin  446  to be seated therein as the latch plate  430  rotates about the drive plate axis  408 . The latch plate  430  includes a releasing lever  458  to which a force may be applied to rotate the latch plate  430  about the drive plate axis  408 . In FIG. 8, the latch plate  430  is also in contact with the brace  604 . 
     The slidable carriage  202  is connected to the drive plate  402  by way of the connecting rod  414  of axis  210  and is rotatable thereabout. The slidable carriage  202  comprises a set of retaining springs  204 , a first retaining bar  206  and a second retaining bar  208 . The retaining springs  204 , disposed within the slidable carriage  202  and acting against the first retaining bar  206 , retain the circuit breaker handle  102  firmly between the first retaining bar  206  and the second retaining bar  208 . The slidable carriage  202  is allowed to move laterally with respect to the side plates  416  by way of the first retaining bar  206  coupled to a slot  214  in each of the side plates  416 . The slidable carriage  202  moves back and forth along the slots  214  to toggle the circuit breaker handle  102  back and forth between the position of FIG.  8  and that of FIG.  12 . 
     In FIG. 8, the molded case circuit breaker  100  is in the closed position (i.e., electrical contacts closed) and no energy is stored in the main spring  302 . The motor operator  200  operates to move the circuit breaker handle  102  between the closed position of FIG.  8  and the open position (i.e., electrical contacts open) of FIG.  12 . In addition, when the molded case circuit breaker  100  trips due for example to an overcurrent condition in an associated electrical system, the 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.  12 . 
     To move the handle from the closed position of FIG. 8 to the open position of FIG. 12, the motor drive assembly  500  rotates the cam  420  clockwise as viewed on the cam shaft  422  such that the mechanical linkage system  400  is sequentially and continuously driven through the configurations of FIGS. 9,  10  and  11 . Referring to FIG. 9, the cam  420  rotates clockwise about the cam shaft  422 . The drive plates  402  are allowed to move due to the slot  404  in the drive plates  402 . The roller  444  on the roller axis  410  moves along the first cam surface  424  of the cam  420 . The counterclockwise rotation of the drive plates  402  drives the drive plate pin  406  along the open slot  316  thereby compressing the main spring  302  and storing energy therein. The energy storage mechanism  300  rotates clockwise about the spring assembly axis  322  and the side plate pin  418 . The latch plate  430 , abutting the brace  604 , remains fixed with respect to the side plates  416 . 
     Referring to FIG. 10, the drive plate  402  rotates further counterclockwise causing the drive plate pin  406  to further compress the main spring  302 . The cam  420  continues to rotate clockwise. The rolling pin  446  moves from the second concave surface  436  of the latch plate  430  partially to the first concave surface  434  and the latch plate  430  rotates clockwise away from the brace  604 . The drive plate pin  406  compresses the main spring  302  further along the open slot  316 . 
     In FIG. 11 the latch plate  430  rotates clockwise until the rolling pin  446  rests fully within the first concave surface  434 . The roller  444  remains in intimate contact with the first cam surface  424  as the cam  420  continues to turn in the clockwise direction. In FIG. 12 the cam  420  has completed its clockwise rotation and the roller  44  is disengaged from the cam  420 . The rolling pin  446  remains in contact with the first concave surface  434  of the latch plate  430 . 
     The mechanical linkage system  400  thence comes to rest in the configuration of FIG.  12 . In proceeding from the configuration of FIG. 8 to that of FIG. 12, the main spring  302  is compressed a distance “x” by the drive plate pin  406  due to the counterclockwise rotation of the drive plates  402  about the drive plate axis  408 . The compression of the main spring  302  thus stores energy in the main spring  302  according to the equation E=½ k m  X 2 , where x is the displacement of the main spring  302 . The motor operator  200 , the energy storage mechanism  300  and the mechanical linkage system  400  are held in the stable position of FIG. 12 by the first latch link  442 , the second latch link  450  and the latch plate  430 . The positioning of the first latch link  442  and the second latch link  450  with respect to one another and with respect to the latch plate  430  and the 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. As seen in FIG. 23, 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 the drive plates  402  and the first latch link  442  clockwise about the drive plate axis  408 , the cam shaft  422  is fixed with respect to the side plates  416  which are in turn affixed to the molded case circuit breaker  100 . Thus, in the configuration FIG. 12 the first latch link  442  and the second latch line  450  form a rigid linkage. There is a tendency for the linkage of the first latch link  442  and the second latch link  450  to rotate about the link axis  412  and collapse. However, this is prevented by a force acting along the line  470  countering the force acting along the 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 the motor operator  200  in the configuration of FIG. 12 are balanced and no rotation of the mechanical linkage system  400  may be had. 
     In FIG. 12 the molded case circuit breaker  100  is in the open position. To proceed from the configuration of FIG.  12  and return to the configuration of FIG. 8 (i.e., electrical contacts closed), a force is applied to the latch plate  430  on the latch plate lever  458  at  460 . The application of this force acts so as to rotate the latch plate  430  counterclockwise about the drive plate axis  408  and allow the rolling pin  446  to move from the first concave surface  434  as in FIG. 12 to the second concave surface  436  as in FIG.  8 . This action releases the energy stored in the main spring  302  and the force acting on the drive plate pin  406  causes the drive plate  402  to rotate clockwise about the drive plate axis  408 . The clockwise rotation of the drive plate  402  applies a force to the circuit breaker handle  102  at the second retaining bar  208  throwing the circuit breaker handle  102  leftward, with the main spring  302 , the latch plate  430  and the mechanical linkage system  400  coming to rest in the position of FIG.  8 . 
     Referring to FIG. 21, the motor drive assembly  500  is shown engaged to the motor operator  200 , the energy storage mechanism  300  and the mechanical linkage system  400 . The motor drive assembly  500  comprises a motor  502  geared to a gear train  504 . The gear train  504  comprises a plurality of gears  506 ,  508 ,  510 ,  512 ,  514 . One of the gears  514  of the gear train  504  is rotatable about an axis  526  and is connected to a disc  516  at the axis  516 . The disc  516  is rotatable about the axis  526 . However, the axis  526  is displaced from the center of the disc  516 . Thus, when the disc  516  rotates due to the action of the motor  502  and gear train  504 , the disc  516  acts in a cam-like manner providing eccentric rotation of the disc  516  about the axis  526 . The motor drive assembly  500  further comprises a unidirectional bearing  522  coupled to the cam shaft  422  and a charging plate  520  connected to a ratchet lever  518 . A roller  530  is rotatably connected to one end of the ratchet lever  518  and rests against the disc  516  (FIG.  22 ). Thus, as the disc  516  rotates about the axis  526 , the ratchet lever  518  toggles back and forth as seen at  528  in FIG.  22 . This back and forth action ratchets the unidirectional bearing  522  a prescribed angular displacement, θ, about the cam shaft  422  which in turn ratchets the cam  420  by a like angular displacement. Referring to FIG. 20, the motor drive assembly  500  further comprises a manual handle  524  coupled to the unidirectional bearing  522  whereby the unidirectional bearing  522 , and thus the cam  420 , may be manually ratcheted by repeatedly depressing the manual handle  524 . 
     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.