Patent Publication Number: US-7586055-B2

Title: Over running clutch for a direct drive motor operator

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application is related to commonly assigned, concurrently filed U.S. patent application Ser. No. 11/733,465, filed Apr. 10, 2007, entitled “MOTOR OPERATOR DE-COUPLING SYSTEM SENSING CAMSHAFT POSITION”, and which is incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an electrical switching apparatus operating mechanism and, more specifically to an over running clutch disposed between the operating mechanism charging motor and the operating mechanism charging handle. 
   2. Background Information 
   An electrical switching apparatus, typically, includes a housing, at least one bus assembly having a pair of contacts, a trip device, and an operating mechanism. The housing assembly is structured to insulate and enclose the other components. The at least one pair of contacts include a fixed contact and a movable contact and typically include multiple pairs of fixed and movable contacts. Each contact is coupled to, and in electrical communication with, a conductive bus that is further coupled to, and in electrical communication with, a line or a load. A trip device is structured to detect an over current condition and to actuate the operating mechanism. The operating mechanism is structured to both open the contacts, either manually or following actuation by the trip device, and close the contacts. 
   That is, the operating mechanism includes both a closing assembly and an opening assembly, which may have common elements, that are structured to move the movable contact between a first, open position, wherein the contacts are separated, and a second, closed position, wherein the contacts are coupled and in electrical communication. The operating mechanism includes a rotatable pole shaft that is coupled to the movable contact and structured to move each movable contact between the closed position and the open position. Elements of both the closing assembly and the opening assembly are coupled to the pole shaft so as to effect the closing and opening of the contacts. 
   An electrical switching apparatus typically had a stored energy device, such as at least one opening spring, and at least one link coupled to the pole shaft. The at least one link, typically, included two links that acted cooperatively as a toggle assembly. When the contacts were open, the toggle assembly was in a first, collapsed configuration and, conversely, when the contacts were closed, the toggle assembly was, typically, in a second, toggle configuration or in a slightly over-toggle configuration. The spring biased the toggle assembly to the collapsed configuration. The spring and toggle assembly were maintained in the second, toggle configuration by the trip device. 
   The trip device included an over-current sensor, a latch assembly and may have included one or more additional links that were coupled to the toggle assembly. Alternately, the latch assembly was directly coupled to the toggle assembly. When an over-current situation occurred, the latch assembly was released allowing the opening spring to cause the toggle assembly to collapse. When the toggle assembly collapsed, the toggle assembly link coupled to the pole shaft caused the pole shaft to rotate and thereby move the movable contacts into the open position. 
   Typically, the force required to close the contacts was, and is, greater than what a human may easily apply. As such, the operating mechanism typically included a mechanical closing assembly to close the contacts. The closing assembly, typically, included at least one stored energy device, such as a spring, and/or a motor. A common configuration included a motor that compressed one or more springs in the closing assembly. That is, the closing springs were coupled to a cam roller that engaged a cam coupled to the motor. As the motor rotated the cam, the closing springs were compressed or charged. The closing springs were maintained in the compressed configuration by a latch assembly. The latch assembly was actuated by a user to initiate a closing procedure. The closing assembly is structured to apply the energy stored in the springs to the toggle assembly so as to cause the pole shaft to rotate and close the contacts. 
   In many electrical switching apparatuses the springs are coupled to the toggle assembly via a cam roller. That is, the toggle assembly also included a cam roller, typically at the toggle joint. The closing assembly further included one or more cams disposed on a common cam shaft with the closing spring cam. Alternatively, depending upon the configuration of the cam, both the closing spring cam roller and the toggle assembly cam roller could engage the same cam. When the closing springs were released, the closing spring cam roller applied force to the associated cam and caused the cam shaft to rotate. Rotation of the cam shaft would also cause the cam associated with the toggle assembly cam roller to rotate. As the cam associated with the toggle assembly cam roller rotated, the cam caused the toggle assembly cam roller, and therefore the toggle assembly, to be moved into selected positions and/or configurations. Alternatively, as set forth in U.S. patent application Ser. No. 11/693,159, which is incorporated by reference, the springs could be coupled to a ram assembly having a ram body that moved over a predetermined path. The ram body was structured to directly engage the toggle assembly and move the toggle assembly into a selected position. That is, whether the closing assembly utilized a cam or a ram assembly, the toggle assembly was moved so as to rotate the pole shaft into a position wherein the contacts were closed. 
   For example, during a closing procedure the toggle assembly would initially be collapsed and, therefore, the contacts were open. When the closing springs were released, the rotation of the cam associated with the toggle assembly cam roller would cause the toggle assembly to move back into the second, toggle position, thereby closing the contacts. This motion would also charge the opening springs. Simultaneously, or near simultaneously, the trip device latch would be reset thereby holding the toggle assembly in the second, toggle position. After the contacts were closed, it was common to recharge the closing spring so that, following an over current trip, the contacts could be rapidly closed again. That is, if the closing springs were charged, the contacts could be closed almost immediately without having to wait to charge the closing springs. 
   As noted above, the charging of the closing springs was typically accomplished via a motor. The motor had an output shaft that was coupled, directly or indirectly, to the shaft of the charging cam. In addition to the charging motor, most electrical switching apparatuses included an elongated manual charging handle. The charging handle also acted upon the shaft of the charging cam either directly or indirectly. To prevent the charging handle from applying torque to the motor when the handle was used to charge the closing springs, a clutch was disposed between the motor and the handle. 
   A common type of clutch utilized in closing assemblies was a reciprocal drive clutch. While such a reciprocal drive clutch functioned well, it does have several disadvantages. First, the reciprocal drive clutch included a number of components which were all subject to wear and tear. Further, the reciprocal drive clutch typically was very noisy, due to non-symmetrical loading. While the noise level does not effect the operation of the device, users could misinterpret the noise level as a mechanical problem. Thus, the noise level is a user perception issue. Similarly, the use of an over running clutch during a motor charging operation allowed the handle to vibrate. Again, this does not effect the operation of the closing assembly, but creates a poor user impression. 
   There is, therefore, a need for an over running clutch assembly having a reduced number of components. 
   There is a further need for an over running clutch assembly structured to operate in a manner with limited observable or audible indications. 
   SUMMARY OF THE INVENTION 
   These needs, and others, are met by the at least one embodiment of the present invention which discloses an over running clutch assembly for an electrical switching apparatus. The over running clutch assembly includes a sprocket and a hub assembly. The hub assembly is rotatably coupled to the sprocket and structured to rotate in a charging direction relative to the sprocket. The sprocket is fixed to a motor shaft. The hub assembly is structured to be disengagably fixed to a cam shaft in the charging assembly. A manual charging handle is also coupled to the cam shaft and is structured to rotate the cam shaft in a charging direction. In this configuration, an operator may charge the closing springs of the electrical switching apparatus using either the handle assembly or the motor. When the handle assembly is used to charge the closing springs, the cam shaft causes the hub assembly to rotate over the sprocket. Thus, the rotation of the cam shaft is not transferred to the motor. When the motor is used, the motor turns both the sprocket and the hub assembly. The hub assembly transfers the rotational force from the motor to the cam shaft. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A full understanding of the invention can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which: 
       FIG. 1  is an isometric view of a electrical switching apparatus with a front cover removed. 
       FIG. 2  is an isometric view of a electrical switching apparatus with a front cover, motor assembly and handle assembly removed. 
       FIGS. 3A and 3B  are side views of a electrical switching apparatus with a front cover removed and selected components removed for clarity.  FIG. 2A  shows the springs in a discharged position.  FIG. 2B  shows the springs in a charged position. 
       FIG. 4  shows an exploded view of an over running clutch assembly. 
       FIG. 4A  shows a detail of the sprocket. 
       FIG. 5  shows an end view of selected components of the charging assembly. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   As used herein, “coupled” means a link between two or more elements, whether direct or indirect, so long as a link occurs. 
   As used herein, “directly coupled” means that two elements are directly in contact with each other. 
   As used herein, “fixedly coupled” or “fixed” means that two components are coupled to move as one. Components that are “fixed” to each other may be “permanently fixed” to each other by a coupling device such as, but not limited to, welding or a difficult to access bolt. Components may also be “disengagably fixed” to each other by a coupling device that, when joined, maintains the components in a set orientation relative to each other, but which may be decoupled. For example, a socket wrench typically includes a ratchet/handle with a rotatable square shaft structured to be “disengagably fixed” to a socket. 
   As shown in  FIG. 1 , an electrical switching apparatus  10  includes a housing assembly  12  defining an enclosed space  14 . In  FIG. 1 , the front cover of the housing assembly  12  is not shown, but it is well known in the art. The electrical switching apparatus  10  further includes a conductor assembly  20  (shown schematically) having at least one line terminal  22 , at least one line conductor  24 , at least one pair of separable contacts  26 , at least one load conductor  28  and at least one load terminal  30 . The at least one pair of separable contacts  26  include a fixed contact  32  and a movable contact  34 . The movable contact  34  is structured to move between a first, open position, wherein the contacts  32 ,  34  are separated, and a second, closed position, wherein the contacts  32 ,  34  contact each other and are in electrical communication. The electrical switching apparatus  10  further includes a trip device  40  and an operating mechanism  50 . The operating mechanism  50  is generally structured to move the at least one pair of separable contacts  26  between the first, open position and the second, closed position. The trip device  40  is structured to detect an over current condition and, upon detecting such a condition, to actuate the operating mechanism  50  to open the at least one pair of separable contacts  26 . 
   The electrical switching apparatus  10  also includes at least two, and typically a plurality, of side plates  27 . The side plates  27  are disposed within the housing assembly  12  in a generally parallel orientation. The side plates  27  include a plurality of openings  29  to which other components may be attached or through which other components may extend. As discussed below, the openings  29  on two adjacent side plates  27  are typically aligned. While side plates  27  are the preferred embodiment, it is understood that the housing assembly  12  may also be adapted to include the required openings and/or attachment points thereby, effectively, incorporating the side plates  27  into the housing assembly  12  (not shown). 
   An electrical switching apparatus  10  may have one or more poles, that is, one or more pairs of separable contacts  26  each having associated conductors and terminals. As shown in the Figures the housing assembly  12  includes three chambers  13 A,  13 B,  13 C each enclosing a pair of separable contacts  26  with each being a pole for the electrical switching apparatus  10 . A three-pole configuration, or a four-pole configuration having a neutral pole, is well known in the art. The operating mechanism  50  is structured to control all the pairs of separable contacts  26  within the electrical switching apparatus  10 . Thus, it is understood selected elements of the operating mechanism  50 , such as, but not limited to, the pole shaft  56  span all three chambers  13 A,  13 B,  13 C and engage each pair of separable contacts  26 . The following discussion, however, shall not specifically address each specific pair of separable contacts  26 . 
   As shown in  FIG. 2 , the operating mechanism  50  includes an opening assembly  52 , structured to move the at least one pair of separable contacts  26  from the second, closed position to the first, open position, and a closing assembly  54 , structured to move the at least one pair of separable contacts  26  from the first, open position to the second closed position. The opening assembly  52  and the closing assembly  54  both utilize common components of the operating mechanism  50 . The opening assembly  52  is not part of the claimed invention, however, for the purpose of the following discussion, it is understood that the opening assembly  52  is the assembly structured to move various components to the positions discussed below. Further, it is noted that the opening assembly  52  includes a cradle assembly  53  that, among other functions, acts as a toggle stop and as a toggle kicker for the toggle assembly  58  (discussed below). 
   Further details relating to the operation of the closing assembly  54  are set forth in U.S. patent application Ser. No. 11/693,159, which, as noted above, is incorporated by reference. That is, as discussed in U.S. patent application Ser. No. 11/693,159, the closing assembly  54  utilizes a ram assembly  60  structured to act upon a toggle assembly  62  wherein the toggle assembly  62  is coupled via a pole shaft  56  to the movable contacts  34 . The ram assembly  60  utilizes energy stored in at least one closing spring  61 . The at least one closing spring  61  is structured to move between a charged and a discharged configuration. The at least one closing spring  61  is compressed, or “charged,” by the charging assembly  70  detailed herein. 
   As shown in  FIGS. 1 and 2 , the charging assembly  70  includes a charging operator  72 , a cam shaft  74 , at least one cam  76 , and a rocker arm assembly  110 . The charging operator  72  is a device coupled to, and structured to rotate, the cam shaft  74 . The charging operator  72 , preferably, includes both a manually powered handle assembly  80  and a powered motor assembly  82  as shown in  FIG. 1 . The cam shaft  74  is an elongated shaft that is rotatably coupled to the housing assembly  12  and/or side plates  27 . The at least one cam  76  is fixed to the cam shaft  74  and structured to rotate therewith about a pivot point. The cam shaft  74  has a distal tip  75  that is spaced from the least one cam  76 . The cam shaft distal tip  75  has a non-circular shape which is, preferably a D-shape as shown. 
   The at least one cam  76 , which hereinafter will be referred to as a single cam, includes an outer cam surface  90 . The outer cam surface  90  has a point of minimal diameter  92 , a point of greatest diameter  94 , also known as “top dead center” of the cam  76 , and a stop diameter  96 . The cam  76  is structured to rotate in a single direction as indicated by the arrow in  FIG. 2 . The outer cam surface  90  increases gradually in diameter from the point of minimal diameter  92  to the point of greatest diameter  94  in the direction of rotation. After the cam point of greatest diameter  94 , the diameter of the outer cam surface  90  is reduced slightly over a downslope  98 . The downslope  98  leads to the stop diameter  96  and then a tip  100 . As set forth in U.S. patent application Ser. No. 11/693,159, the downslope  98  to the stop diameter  96  is a surface to which the force from the at least one closing spring  61  is applied via a rocker arm assembly  110 , discussed below, and which encourages rotation in the proper direction so that when the latch assembly  79  is released, the cam shaft  74  rotates and the rocker arm assembly  110  moves from the stop diameter  96  to the cam tip  100  where the cam follower  116  falls off the cam tip  100  and into the pocket of the cam  76 . As is shown, the outer cam surface point of minimal diameter  92  and the outer cam tip  100  are disposed immediately adjacent to each other on the outer cam surface  90 . Thus, there is a step  102  between the point of minimal diameter  92  and the cam tip  100 . It is further noted that, due to the diameter of the rocker assembly cam follower  116  (discussed below) the rocker assembly cam follower  116  does not engage the point of minimal diameter  92 , but rather engages a location immediately adjacent to the point of minimal diameter  92 . 
   The rocker arm assembly  110  includes an elongated body  112  having a pivot point  114 , a cam follower  116 , and a ram body contact point  118 . The rocker arm assembly body  112  is pivotally coupled to housing assembly  12  and/or side plates  27  at the rocker arm body pivot point  114 . The rocker arm assembly body  112  may rotate about the rocker arm body pivot point  114  and is structured to move between a first position, wherein the rocker arm body ram body contact point  118  is disposed adjacent to a ram assembly base plate, and a second position, wherein the rocker arm body ram body contact point  118  is adjacent to a ram assembly stop plate. As used immediately above, “adjacent” is a comparative adjective relating to the positions of the rocker arm assembly body  112 . The rocker arm body ram body contact point  118  is structured to engage and move the ram assembly  60  and thereby compress the at least one closing spring  61 . The rocker arm assembly body  112  moves within a plane generally parallel to the plane of the side plates  27 . The rocker arm body cam follower  116  extends generally perpendicular to the longitudinal axis of the rocker arm assembly body  112  and is structured to engage the outer cam surface  90 . The rocker arm body cam follower  116  may include a roller  117 . Thus, charging of the at least one closing spring  61  is accomplished by the rotation of the cam  76 . The rotation of the cam  76  is arrested by a latch assembly  79  when the rocker arm body cam follower  116  is at the stop diameter  96  as discussed in U.S. patent application Ser. No. 11/693,159. 
   Rotation of the cam  76  is accomplished by using the handle assembly  80  or the motor assembly  82 . The handle assembly  80  is coupled to the cam shaft  74  at a point between the cam shaft distal tip  75  and the at least one cam  76 . The handle assembly  80  includes an elongated handle  120  and a ratchet assembly  122 . As is known in the art, the handle  120  is coupled to the ratchet assembly  122 . The ratchet assembly  122  is coupled to the cam shaft  74  and structured to rotate the cam shaft  74  in the charging direction (as indicated by the arrow on  FIG. 2A ). That is, the ratchet assembly  122  includes a rack of teeth (not shown) and a pawl (not shown). The rack of teeth is coupled, or fixed, to the cam shaft  74 . The pawl is coupled to the handle  120  and, when the handle  120  is moved in a first direction, the pawl passes over the rack of teeth. When the handle  120  is moved in the opposite direction, the pawl engages the rack of teeth and causes the cam shaft  74  to rotate in the charging direction. 
   The motor assembly  82  includes a motor  130  and a shaft  132 . The motor  130  is structured to rotate the motor shaft  132  in the charging direction. The motor shaft  132  has a distal end  134 . When the motor assembly  82  is installed in the housing assembly  12 , the axis of the motor shaft  132  is aligned with the cam shaft  74  with the motor shaft distal end  134  adjacent to the cam shaft distal tip  75 . The motor shaft  132  and the cam shaft  74  are coupled by an over running clutch assembly  140 . The motor assembly  82  may include two side plates  136  which are held in a spaced relation and which define a clutch space  138 . The over running clutch assembly  140  is disposed in the clutch space  138  and together with the motor assembly  82  is removable from the housing assembly  12  as a unit. The motor assembly  82  preferably includes an electronic cutoff switch  139  (as discussed below). 
   The charging assembly  70  also includes an over running clutch assembly  140 . The over running clutch assembly  140  includes a sprocket  142  and a hub assembly  144 . The sprocket  142  is structured to be fixed to the motor shaft distal end  134 . The sprocket  142  has a generally flat, disk-like body  146  having a central opening  148  and a radial outer surface  150  having a number of generally uniform teeth  152 . Preferably, the teeth  152  are symmetrical about a central point having a generally smooth top  153  and a generally U-shaped sidewall  155  between the teeth tops  153 . The U-shaped sidewall  155  has a descending side  157  and an ascending side  159 , as described below. The teeth  152  may also be jagged (not shown) in a manner similar to the teeth on a ratchet rack. The sprocket central opening  148  preferably has a non-circular shape, such as a D shape as shown. The motor shaft  132  has a shape corresponding to the shape of the sprocket central opening  148  and, as such, when the sprocket  142  is coupled to the motor shaft  132  with the motor shaft  132  extending into, or through, the sprocket central opening  148 , the sprocket  142  is fixed to the motor shaft  132  and rotates therewith. The sprocket  142  also includes a collar  154 . The collar  154  is, essentially, a circular cap that is disposed over the end of the motor shaft  132 . 
   The hub assembly  144  is structured to be disengagably fixed to the cam shaft  74  and rotatably coupled to the sprocket  142 . The hub assembly  144  includes a hub body  160  and a link assembly  170 . The hub body  160  is generally planar with a first face  162  and a second face  164 . The hub body  160  further includes a link assembly mounting point  166 , a sprocket socket  167 , and a cam shaft socket  168 . The sprocket socket  167  is disposed on the first face  162 . The sprocket socket  167  is generally circular and sized to correspond to the size of the collar  154 . That is, the collar  154  may be rotatably disposed within the sprocket socket  167 . The cam shaft socket  168  is disposed on the second face  164 . The cam shaft socket  168  has a shape that corresponds to the shape of the cam shaft distal tip  75  which, as shown, is preferably a D shape. The center of the sprocket socket  167  and the center of the cam shaft socket  168  are aligned and define an axis of rotation for the hub body  160 . 
   The link assembly  170  includes a link member  172  having an elongated body  174 , a spring  176  and a pawl  178 . The link member elongated body  174  has a first end  180  and a pivot mounting  182 . The link member elongated body  174 , as described below, is coupled to the hub body  160  and the longitudinal axis of the link member elongated body  174  extends in a plane generally parallel to the plane of the hub body  160 . The pawl  178  is disposed at the link member body first end  180 . The pawl  178  extends in a direction generally perpendicular to the plane of the hub body  160 . 
   The hub assembly  144  is assembled as follows. The link member elongated body  174  is pivotally coupled to the hub body  160 . More specifically, the link member elongated body pivot mounting  182  is coupled to the link assembly mounting point  166 . The link assembly spring  176  is disposed between, and coupled to both, the link member elongated body  174  and the hub body  160 . The link assembly spring  176  is structured to bias the link member body first end  180  towards the hub body  160 . Thus, the pawl  178  is also biased toward the hub body  160 . The pawl  178 , as well as the link member  172 , is structured to move between a first position, wherein the pawl  178  engages the sprocket radial outer surface  150 , and a second position, wherein the pawl  178  does not engage the sprocket radial outer surface  150 . Movement of the pawl  178  into the second position is detailed in concurrently filed U.S. patent application Ser. No. 11/733,465, filed Apr. 10, 2007, entitled “MOTOR OPERATOR DE-COUPLING SYSTEM SENSING CAMSHAFT POSITION”. As set forth below, when the pawl  178  is in the first position, the pawl  178  may move over the sprocket radial outer surface  150  when the hub assembly  144  is rotated in the charging direction. 
   The over running clutch assembly  140  is assembled as follows. The hub assembly  144  is rotatably coupled to the sprocket  142 . That is, the collar  154  is disposed within the sprocket socket  167 . Because the collar  154  and the sprocket socket  167  are both generally circular, the hub assembly  144  may rotate relative to the sprocket  142 . The hub body  160  and the sprocket body  146  extend, generally, in parallel planes. Thus, the pawl  178  extends perpendicularly toward the sprocket body  146  and engages the teeth  152 . Further, relative to the charging direction, the link assembly mounting point  166  is disposed behind the pawl  178 . The link assembly mounting point  166  is also disposed so that, when the pawl  178  is disposed between the sprocket teeth tops  153 , that is, when the pawl  178  is disposed over the U-shaped sidewall  155  between the teeth tops  153 , a line extending between the link assembly mounting point  166  and the pawl  178  intersects the descending side  157  of the U-shaped sidewall  155  where the pawl  178  is located. 
   In this configuration, the hub assembly  144  may only rotate in the charging direction relative to the sprocket  142 . That is, the pawl  178  moves over the sprocket outer surface  150  in a single direction, the charging direction. Given this direction of motion of the pawl  178 , the U-shaped sidewall  155  may be said to have a descending side  157  and an ascending side  159 . As the pawl  178  moves over a tooth top  153  and enters the U-shaped sidewall  155 , the pawl  178  “descends” over the descending side  157 . When the pawl  178  moves out of the U-shaped sidewall  155 , the pawl  178  “ascends” over the ascending side  159 . It is noted that, due to the position of the link assembly mounting point  166 , as described above, the descending side  157  is generally perpendicular to the line extending between the link assembly mounting point  166  and the pawl  178 . However, due to the curvature of the sprocket  142 , the line extending between the link assembly mounting point  166  and the pawl  178  may not cross over the ascending side  159 , or, if the line extending between the link assembly mounting point  166  and the pawl  178  does cross over the ascending side  159 , the line does so at an angle of less than about 80 degrees. 
   Thus, when a rotational force is applied to the hub assembly  144  in the charging direction, the force applied to the link member elongated body  174  overcomes the bias of the link assembly spring  176  and the pawl  178  moves over the sprocket outer surface  150 . More specifically, the rotational force causes a force on the pawl  178  that acts along the line extending between the link assembly mounting point  166  and the pawl  178 . When the rotation force is applied in the charging direction, the resulting force on the pawl  178  acts in a direction away from the link assembly mounting point  166 . Because this force is acting along a line that does not intersect, or intersects at an angle, the ascending side  159 , the pawl  178  may move over the sprocket outer surface  150 . Thus, when a rotational force in the charging direction is applied to the hub assembly  144 , e.g. a force created by a user operating the handle assembly  80 , the hub assembly  144  rotates in the charging direction relative to the sprocket  142 . 
   When a rotational force is applied to the hub assembly  144  opposite the charging direction, the force applied to the link member elongated body  174  does not overcome the bias of the link assembly spring  176  and the pawl  178  cannot move over the sprocket outer surface  150 . That is, due to the position of the link assembly mounting point  166 , as set forth above, a rotational force applied to the hub assembly  144  in a direction opposite the charging direction causes the pawl  178  to engage, or be pulled against, the U-shaped sidewall  155  where the pawl  178  is located. That is, the force on the pawl  178  acts in a line between the pawl  178  and the link assembly mounting point  166 . As set forth above, this line intersects the descending side  157  at about a right angle. Thus, the force is, essentially, directed into the sprocket  142  and as such, the force cannot overcome the bias of the link assembly spring  176  and the pawl  178  cannot move out of the U-shaped sidewall  155 . It is further noted that when the sprocket  142  is rotated by the motor  130  in the charging direction, the forces applied to the hub assembly  144  are similar to applying a rotational force to the hub assembly  144  opposite the charging direction. Thus, when the motor  130  rotates the sprocket  142 , the hub assembly  144  rotates with the sprocket  142  in the charging direction. 
   Finally, as noted above, the cam shaft socket  168  and the cam shaft distal tip  75  have corresponding shapes, preferably a D shape. The cam shaft distal tip  75  may be inserted, or removed, from the cam shaft socket  168 . Because the cam shaft socket  168  and the cam shaft distal tip  75  are non-circular, when the components are coupled, the components will move in a fixed orientation relative to each other. That is, the cam shaft socket  168  may be disengagably fixed to the cam shaft distal tip  75 . Alternately stated, the cam shaft  74  is disengagably fixed to the hub assembly  144 . Thus, the motor assembly  82  and the over running clutch assembly  140  may be removed or installed as a unit from the housing assembly  12 . 
   In operation, in this configuration, the handle assembly  80  is structured to rotate the cam shaft  74  and the hub assembly  144 , with the hub assembly  144  rotating on the sprocket  142 . Further, the motor assembly  82  is structured to rotate the cam shaft  74 , the hub assembly  144  and the sprocket  142 , with the hub assembly  144  rotating with the sprocket  142 . 
   While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.