Racking device and power module therefor

A racking device performs a circuit breaker racking operation. The racking device includes a base with wheels and a brake to facilitate moving the racking device and positioning it with respect to a switchgear cabinet. An elongated tubular member extends substantially vertically from the base. A self-contained counter-balanced power module includes an enclosure having a pair of opposing openings for receiving the elongated tubular member, and a counterweight system for counter-balancing the power module. An actuator including a motor, a ball spline and a torque member moves a linkage assembly having an end effector with a negator spring that positively engages the circuit breaker. A switch module actuates the actuator from a remote location in order to move the linkage assembly and thus the circuit breaker to perform the racking operation from the remote location. Complicated field programming of the power module is not required.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to electrical apparatus and, more particularly, to a racking device for manipulating an electrical switching apparatus, such as a circuit breaker. The invention also relates to a power module for a racking device.

2. Background Information

Electrical switching apparatus, such as relatively large circuit breakers, are commonly disposed in an enclosure or housing structure having a plurality of compartments or sections. The circuit breakers may be stacked, as shown inFIG. 1, or they may be disposed in any other suitable configuration within the housing structure. Large circuit breakers are typically heavy, often weighing as much as 1000 lbs. or more. Therefore, in order to facilitate the manipulation (e.g., insertion, removal, adjustment, or any other movement) of the circuit breaker, it is usually necessary to employ a moving device commonly referred to as an extraction or racking device.

FIG. 1shows an example of a racking device2comprising a frame4including a bucket6for supporting the electrical apparatus (e.g., circuit breaker8) being manipulated. A drive gear10is used to move the bucket6vertically along a pair of guide rails12(only one rail12is shown), and a set of trucks or wheels14are disposed on an elongated base5for moving the entire racking device2toward and away from the housing structure16. By way of example, in operation, the racking device2is generally placed in front of the housing structure16with the guide rails12being aligned with the vertical sides of the housing structure16. Brakes (not shown inFIG. 1) on each wheel14are then set in order to lock the wheels14. The circuit breaker8, which typically has a pair of roller wheels18, is then rolled out of the housing structure16onto the bucket6of the racking device2. Once the circuit breaker8is on the racking device2, the brakes are released to remove the circuit breaker8. Installation of a circuit breaker8follows essentially the same procedure, except in reverse. Other circuit breaker manipulations, such as shuffling the position of one or more circuit breakers within the housing structure16, can also be accomplished using the vertical movement capabilities of the racking device2.

Racking devices of this nature suffer from a number of disadvantages. Among them is the fact that the racking device2is generally bulky and awkward to manipulate. Specifically, the base5of the frame4of the racking device2extends from the guide rails12a relatively far lateral distance thereby making the device base5unnecessarily large and difficult to transport and maneuver and align with respect to the housing structure16. The bucket6is also generally heavy and difficult to adjust vertically. There is, therefore, a need for a smaller, more compact and maneuverable racking device.

Additionally, conventionally, an operator performing the circuit breaker manipulation has been required to be in physical proximity with the racking device2. Therefore, the operators are typically required to wear approved personal protection equipment (PPE) to resist serious injury that could result if an electrical failure were to occur during the racking process. However, PPE is generally bulky, hot and uncomfortable which dissuades operators from wearing it. An alternative solution is desired. There is, therefore, also a need for a racking device which may be remotely operated.

U.S. Patent Application Pub. No. 2003/0200648 is an example of one attempt to provide a remote power racking system. Like the racking device2ofFIG. 1, the disclosed racking apparatus includes a frame forming a large base and a pair of guide rails extending upwardly from the base. Also included are an electric motor having a shaft, an adaptor arranged to be coupled to an industrial circuit breaker, and an actuating assembly which provides vertical movement of the motor. A controller is carried by the frame for controlling the motor and the actuating structure and a control station is operatively associated with the controller in order to operate the controller from a remote location. However, not only are the frame and the base portion thereof large and difficult to maneuver, but the system is also complex. For example, vertical movement of the motor actuating assembly requires the combination of multiple components including at least a chain, sprockets, a second motor, and a piston and actuator, in order to provide vertical movement of the motor on the frame guide rails. The motor and shaft assembly are also relatively heavy, making manual vertical adjustment of the device very difficult for the operator. The associated method of operating the racking apparatus is also complex. Specifically, among the requirements of the disclosed racking apparatus is that it relies upon a torque profiler, for example, which is dependent upon the exact type of circuit breaker and its location (e.g. cell) on the rack in order to profile torque over the entire range of movement of a racking operation. There is, therefore, a further need for a simplified racking device and method which are universally compatible with a wide variety of circuit breakers.

In summary, there is a need for a racking device that is easy and quick to set-up, is portable and easy to maneuver, is compatible with numerous circuit breaker models, is remotely operable, and which requires minimal programming.

There is, therefore, room for improvement in racking devices and in power modules for racking devices.

SUMMARY OF THE INVENTION

These needs and others are satisfied by the present invention, which is directed to a racking device having a relatively compact and simplified design, including an improved power module which enables the quick and easy manipulation of a wide variety of electrical apparatus with respect to a housing structure.

As one aspect of the invention, a power module is for a racking device having a base and a guide rail extending substantially vertically from the base. The racking device is structured to manipulate an electrical apparatus with respect to a housing structure and comprises: an enclosure including a pair of opposing openings structured to receive the guide rail of the racking device; a counter-balanced guide assembly structured to interconnect the guide rail and the power module in order to facilitate vertical movement of the power module with respect to the base of the racking device; an actuator substantially enclosed within the enclosure; and a linkage assembly coupled to the actuator and structured to be coupled to the electrical apparatus, the actuator being structured to move the linkage assembly thereby moving the electrical apparatus with respect to the housing structure.

The actuator may comprise a motor including a drive member and a torque member and the linkage assembly may comprise at least one of an end effector and at least one connector wherein the end effector is structured to be coupled to the electrical apparatus and, the at least one connector is structured to couple the torque member to the end effector. The motor actuates the drive member which moves the torque member and the at least one of an end effector and at least one connector, in order to at least partially insert or remove the electrical apparatus with respect to the housing structure.

As another aspect of the invention, a power module is for a racking device having a base and a guide rail extending substantially vertically from the base. The racking device is structured to manipulate an electrical apparatus with respect to a housing structure and comprises: an enclosure including a pair of opposing openings structured to receive the guide rail of the racking device; a counter-balanced guide assembly structured to interconnect the guide rail and the power module in order to facilitate vertical movement of the power module with respect to the base of the racking device; an actuator substantially enclosed within the enclosure; a linkage assembly coupled to the actuator and structured to be coupled to the electrical apparatus, the actuator being structured to move the linkage assembly thereby moving the electrical apparatus with respect to the housing structure; and a controller structured to operate the power module and the actuator thereof from a remote location in order to perform a racking operation of the electrical apparatus from the remote location.

The power module may include a status indicator structured to provide an indication of the status of the racking operation, which is readily apparent from the remote location.

As another aspect of the invention, a racking device is for performing a racking operation of an electrical apparatus with respect to a housing structure. The racking device comprises: a base including a maneuvering mechanism structured to facilitate moving the racking device and positioning the racking device with respect to the housing structure; an elongated tubular member extending substantially vertically from the base; and a counter-balanced power module structured to perform the racking operation of the electrical apparatus, the counter-balanced power module comprising: an enclosure including a pair of opposing openings for receiving the elongated tubular member therethrough, a counterweight system structured to facilitate vertical movement of the counter-balanced power module with respect to the base, the counterweight system including at least one weight, at least one pulley coupled to the elongated tubular member, and at least one cable coupled at one end to the at least one weight, extending over the at least one pulley, and coupled at the other end to the counter-balanced power module, an actuator substantially enclosed within the enclosure, and a linkage assembly coupled to the actuator and structured to be coupled to the electrical apparatus, the actuator being structured to move the linkage assembly thereby moving the electrical apparatus in order to perform the racking operation.

The at least one weight of the counterweight system may be structured to counter-balance at least a portion of the mass of the power module in order to further facilitate vertical movement of the power module with respect to the base of the racking device. The weight, the pulley, and the cable of the counterweight system may be disposed within the elongated tubular member. The counter-balanced power module may further include a plurality of guide members, such as guide wheels, that are structured to engage the elongated tubular member in order to align and further facilitate vertical movement of the counter-balanced power module on the elongated tubular member.

The base may be a unitary member which does not require separate elongated foot portions and which includes a first pair of wheels and a second pair of wheels wherein the base has a lateral width and a wheelbase substantially defined by the distance between the first and second pairs of wheels, and wherein the dimension of the lateral width and the wheelbase are generally equal in order to further facilitate maneuvering the racking device.

The electrical apparatus may be a circuit breaker and the housing structure may be a switchgear cabinet.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of illustration, the invention will be described as applied to relatively large circuit breakers (e.g., up to about 1,000 lbs. or more), although it will become apparent that it could also be applied to other types of electrical apparatus (e.g., without limitation, circuit switching devices and other circuit interrupters such as contactors, motor starters, motor controllers and other load controllers) housed within a housing structure, such as a metallic switchgear cabinet or metal clad power circuit breaker rack structure.

As employed herein, the term “fastener” refers to any suitable connecting or tightening mechanism expressly including, but not limited to, screws, bolts and the combinations of bolts and nuts (e.g., without limitation, lock nuts) and bolts, washers and nuts.

As employed herein, the term “racking” refers to any suitable manipulation of an electrical apparatus, such as a circuit breaker, with respect to a housing structure (e.g., without limitation, switchgear cabinet) and expressly includes, without limitation, insertion or removal of the circuit breaker from the switchgear cabinet.

As employed herein, the term “counter-balanced” shall mean structured to reduce the requisite actuation force. For example, the exemplary power module of the racking device of the invention is “counter-balanced” such that it may be moved vertically (e.g., lifted) by exerting a force which is less than the actual weight of the power module. Such counter-balancing may be accomplished by any suitable means, including, for example, without limitation, a series of springs or a counterweight system such as the exemplary weight, pulley, and cable combination illustrated and discussed herein.

As employed herein, the term “linkage” refers to any known or suitable mechanism (e.g., without limitation, a cable; a wire; a chain; a number of interconnected links; a rigid member such as a socket extension) for interconnecting one component to another in order to provide mechanical communication therebetween. For example, the exemplary linkage assembly of the invention comprises at least one of an end effector and at least one connector although other known or suitable combinations are contemplated.

FIG. 2shows a racking device102for performing a racking operation of an electrical apparatus, such as circuit breaker108(shown in simplified form in hidden line drawing), with respect to a housing structure, such as the switchgear cabinet116shown. The racking device102includes a base104having a maneuvering mechanism114structured to facilitate moving the racking device102and positioning it with respect to the switchgear cabinet116. A guide rail106, which is an elongated tubular member, extends substantially vertically from the base104, and a power module130, which is structured to substantially perform the racking operation of the circuit breaker108, is coupled to the guide rail106.

The exemplary power module130is counter-balanced and includes an enclosure132having a pair of opposing openings134,135(best shown by opening134inFIG. 4) structured to receive the guide rail106of the racking device102therethrough. In the example ofFIG. 2, the power module130further includes a counter-balanced guide assembly136which generally comprises a counterweight system138structured to facilitate vertical movement of the counter-balanced power module130with respect to the base104. Specifically, the counterweight system138includes at least one weight140, at least one pulley142coupled to the guide rail106, and at least one cable144. As shown inFIG. 2, and as previously discussed, the guide rail106is an elongated tubular member having a first end110coupled to the base104of the racking device102, and a second end1112. The exemplary counterweight system138includes one counterweight140, one pulley142coupled to the second end112of the guide rail106, and one cable144, all of which are disposed within the elongated tubular member106, as shown. More specifically, the first end of cable144is coupled to the counterweight140. The cable144then extends upward (from the perspective ofFIG. 2) over the exemplary pulley142coupled at the top of the guide rail106, as shown, and then extends downward (from the perspective ofFIG. 2) in order to couple, at the opposite end, to the power module130. In this manner, the counterweight system138functions to counter-balance at least a portion of the mass of the power module130in order to further facilitate vertical movement of the power module130with respect to the base104of the racking device102. In the example ofFIG. 2, the weight of the exemplary counterweight140is generally equal to the mass of the power module130. As employed herein, the term “mass” is substantially interchangeable with the term “weight,” but is used for simplicity of disclosure to differentiate the “mass” of the power module130from the “weight”140of the counterweight system138. Accordingly, as will be discussed in further detail hereinbelow, because of the counter-balanced nature of the exemplary power module130of the invention, alignment of the power module130with the circuit breaker108, is quick and easy to achieve. The exemplary counterweight system138is also contemplated as having a quick-disconnect fastener (not shown) between the cable144and the power module130which allows the power module130to be quickly and easily removed and replaced with another module (not shown). It will be appreciated, however, that the configuration of the counterweight system138is not limited to the example shown and discussed herein. Any known or suitable alternative configuration could be employed. It will also be appreciated from the disclosure herein that an alternative counter-balancing mechanism, such as, for example, a plurality of springs (not shown) or other suitable resilient members, could be employed in place of the exemplary counterweight system138.

Continuing to refer toFIG. 2, the power module130also includes an actuator150generally enclosed (except for the torque member156) within the power module enclosure132when it is retracted as shown, or by a Bellows when it is extended (not shown). The Bellows is a cover for the ball spline154(FIG. 4) to protect the ball spline154, from dust, for example, as it extends from the enclosure132during a racking operation. A linkage assembly160coupled to the actuator150and structured to be coupled to the circuit breaker108. The linkage assembly160includes at least one of an end effector162and at least one connector170. The end effector162has a first end164structured to be coupled to the circuit breaker108and a second end166coupled directly to one of the connector170, as shown, or a torque member156of the actuator150. In other words, while the exemplary linkage assembly160includes both the connector170and the end effector162, only one component (e.g., the end effector162) is actually necessary. The exemplary connector170is a conventional socket extension of the type commonly available in a standard socket set and used with power tools (e.g., without limitation, a torque wrench). Therefore, the connector170provides a convenient tool for extending the reach of the racking device102in order to engage a variety of electrical apparatus (e.g., circuit breaker108) to perform racking operations thereon. It will be appreciated that more than one connector170may be employed between the end effector162and actuator150.

The exemplary end effector162includes a first end164structured to engage the circuit breaker108at a circuit breaker interface171. The interface171often varies depending on the type of circuit breaker108being racked. Accordingly, different end effectors162having different, corresponding engaging means168, are selected in order to engage the particular circuit breaker108. By way of example, the engaging means for engaging interface171often comprises conventional hex head socket168similar to that of connector170. Other times, the circuit breaker will have as the interface, a pin (not shown). An end effector having a corresponding groove (not shown) is then selected and employed. However, it will be appreciated that any known or suitable alternative engaging means168could be employed.

As will be appreciated with reference toFIGS. 2 and 3, in operation, the racking device102is first maneuvered into a position which is generally aligned with the front of the switchgear cabinet116(FIG. 2). This operation is made easier by a number of unique features of the invention. Specifically, the base104of the racking device102comprises a unitary member which eliminates the elongated and cumbersome foot portion frame members of known racking devices (e.g., base5of frame4of the racking device2ofFIG. 1). The base104further includes a maneuvering mechanism consisting of a plurality of wheels114,118and a brake120(FIG. 2). At least two of the wheels114pivot in order to provide the base104with 360 degrees of rotation. As partially shown inFIG. 3, the exemplary base104has four castoring wheels114,115(two wheels114,115are shown). Additionally, although other configurations are within the scope of the invention, the exemplary wheels114,118are arranged in opposing first and second pairs114,118with the exemplary second pair118comprising a relatively large, robust pair of wheels which are larger in diameter than wheels114and are, therefore, suitable to traverse rough terrain. The base104has a wheel base124(FIG. 3) which is substantially defined by the distance between the first and second pairs of wheels114,118. The base104also has a lateral width122, as shown inFIG. 3. As best shown inFIG. 3, the example dimensions of lateral width122and the wheel base124(FIG. 3), are generally equivalent. Such a design further aids quick and easy maneuvering of the racking device102. Additionally, the relatively short wheel base124enables the entire racking device102to be tilted (not shown) for easy movement of the device, for example, using a single pair of the wheels (e.g., second pair118) and using the guide rail106to maneuver the device102in a manner similar to the way a dolly or handtruck is used to move items. Accordingly, the overall generally small and compact design of the exemplary racking device102, in comparison with known devices (e.g., racking device2ofFIG. 1) further simplifies transport and application of the device102.

The brake120(FIG. 2) of the racking device102can be actuated in order to lock the base104in place. This operation is typically performed after final set-up and alignment of the racking device102is achieved, but may alternatively be done any time it is desired to hold the position of the device102, for example, with respect to the switchgear cabinet1116(FIG. 2). The exemplary brake is a single foot actuated brake120(FIG. 2) although any known or suitable alternative braking mechanism (not shown) could be employed. Next, the end effector162is inserted into the circuit breaker interface171(FIG. 2). The extension170is then coupled to the torque member156of the actuator150and the counter-balanced power module130is adjusted vertically upon the guide rail106in order to generally align the extension170with the second end166of the end effector162. Due to the aforementioned counter-balanced nature of the power module130, such vertical adjustment requires only a few pounds of force making it extremely easy to perform. Next, a positive pressure knob196disposed on the enclosure132of the power module130, as shown inFIG. 2, can be actuated in order to extend the extension170for insertion into the second end166of the end effector162. If additional alignment or adjustment is required, a jog button198disposed on the power module130, as shown inFIGS. 2 and 3, may be employed to make relatively minor adjustments and complete the engagement process. Once aligned and engaged, an insert/remove switch200on the power module130is actuated to select the desired insertion or removal racking operation. The actuator150of the exemplary power module130may be preprogrammed to perform racking operations on a variety of different electrical apparatus (e.g., circuit breaker108ofFIG. 2). If the electrical apparatus108being manipulated is one of such pre-programmed apparatus, it may be selected by actuating a breaker select button202on the enclosure132of the power module130. A visual display204on the exterior of the enclosure132facilitates this process. However, it will be appreciated that the exemplary power module130need not be pre-programmed or pre-programmable.

As previously discussed, in order to avoid potential danger associated with, for example, arc flash that may occur during a racking operation, it is necessary to perform the racking operation from a location remote from the racking device102. In order to accomplish this goal, the exemplary racking device102includes a remote electrical switch module180including the number of directional controls on switches184,186for remotely operating the power module130and actuator150thereof, from the remote location (e.g., about 25 feet or more from the open or closed face of the switchgear cabinet116(FIG. 2)). The exemplary switch module180is a handhold module containing a first directional switch or insert button184and a second directional switch or remove button186, as shown inFIG. 2, although other configurations could be employed. For example, while the exemplary remote electrical switch module180is coupled to the power module130by way of an electrical cable182, it could be a remote control (not shown) without any mechanical connection with the power module130.

The exemplary power module130further includes a status indicator188which is readily viewable from the remote location. The status indicator188in the example ofFIGS. 2 and 3, includes three different colored lights, a green light190, an amber light192and a red light194. For the insertion process, the green light190indicates that the unit is in a state safe to initiate a racking operation of the breaker108, and the red light194illuminates when the process is completed successfully. For the removal process, the red light194indicates that the unit is in a state safe to initiate a racking out operation of the breaker, and the green light190illuminates when the process is completed successfully. The amber light192illuminates during a racking operation in order to provide a warning to stay clear of the switchgear cabinet116. A racking operation that does not complete successfully is indicated by alternately flashing amber and red lights192,194. Of course, other light indicator sequences could be employed or other known or suitable indicators (not shown) could be used instead of the exemplary indicator188.

Insertion or removal of the circuit breaker108may be accomplished manually (e.g., by merely depressing one of the directional buttons184,186of switch module180), or by selecting a pre-programmed racking operation and initiating such racking operation by actuating the correct directional control button184,186. Specifically, as will be understood with reference toFIG. 4, the exemplary racking procedure is accomplished by achieving a number of turns of the actuator150. The exemplary actuator150comprises a motor152including a drive member, such as the exemplary ball spline154(shown in hidden line drawing), and the torque member156. The exemplary actuator assembly150is driven by a drive chain158connecting the motor152to the torque member156by way of a pair of sprockets155,157. Accordingly, the motor152is structured to actuate the ball spline154by way of the chain158driven torque member156which rotates the ball spline154. The ball spline154extends from the power module casing132as a result of constant force springs185, thereby driving the linkage assembly160(FIG. 2) connected thereto and to the circuit breaker108(FIG. 2), which results in the insertion of the circuit breaker108from the switchgear cabinet116(FIG. 2). Specifically, a constant outward force is maintained on the ball spline shaft154by the arrangement of constant force springs185. Rather than exerting a force which, for example increases with displacement like conventional torsion or coil springs, the exemplary constant force springs185apply a constant force in order to bias the ball spline154outward and maintain attachment between the end effector162(FIG. 2) and circuit breaker interface171(FIG. 2). In other words, a constant force, towards the circuit breaker108, is maintained throughout the racking operation. Conversely, during a circuit breaker extraction operation, the ball spline154retracts within the power module casing132in response to the inward force exerted by the circuit breaker108on the ball spline154. Accordingly, the rotation and translation of the exemplary ball spline154are independent of one another.

To prevent possible injury to an operator, for example, by uncontrolled acceleration of the ball spline shaft154due to the aforementioned spring bias, the ball spline shaft154is coupled to a rotary damper187through another constant force spring189. This spring189is used as both an interconnecting mechanism and as a recoil mechanism for the damper187in order to restrict the velocity of the shaft154when it exits the enclosure132. More specifically, a latch (not shown) is provided to hold the ball spline shaft154at its fully withdrawn position (shown), and a switch (not shown) is employed to ensure that the latch is released before an insertion or removal racking process will be started. A multi-turn potentiometer191is coupled to the rotary damper187in order to detect or infer the ball spline shaft154position thereby determining whether or not sufficient shaft travel is available to complete the racking process for the selected breaker type. Accordingly, it will be appreciated that the actuator150can be pre-programmed, as previously discussed, in order to turn the exemplary ball spline shaft154(FIG. 4) a predetermined number of turns corresponding to, for example, the racking characteristics of the particular electrical apparatus (e.g., circuit breaker108ofFIG. 2) being manipulated. The programming generally involves counting the number of turns of the ball spline shaft154and monitoring the current provided by the motor152. Therefore, in operation, the ball spline154is driven slowly initially and near the end of the racking operation in order to, for example, ensure that torque is not excessively high. For example, if excessive torque is not detected, the speed is increased as the racking operation is performed, until a certain number of turns are achieved, at which point the speed is decreased again until the current indicates a spike in the torque, which is indicative of the circuit breaker108being fully racked (e.g., inserted) or fully removed. To protect against damage, due to such sudden torque increases, the exemplary torque member comprises a slip clutch156which slips at a predetermined level of torque to avoid damaging circuit breaker components. This pre-programming in the example ofFIG. 3, is accomplished by way of a suitable processor or computer206disposed within the power module130of the racking device102. Thus, essentially all of the electronics (e.g., without limitation, computer206) of the exemplary racking device102are disposed within the power module130, which is, therefore self-contained and thus removable, replaceable, and interchangeable with other power modules, for example, having a different size motor.

It will be appreciated, with reference toFIGS. 3 and 4, that a direct drive adapter (not shown), for coupling, for example, the socket extension170ofFIG. 2, directly to the sprocket155(FIG. 4) instead of employing the aforementioned gear reduction and ball spline154and drive member150(FIG. 4), is also contemplated by the invention. More specifically, such direct drive would couple directly to the motor152(FIG. 4) proximate the sprocket155in order to provide the higher speeds and mechanical advantage offered by a direct drive, which is suitable for certain circuit breaker racking operations. Access for attaching the direct drive adapter (not shown) to the motor152(FIG. 4) would be provided through an access hole159(shown in phantom line drawing inFIG. 3) in the power module enclosure132.

Accordingly, the invention provides a racking device102with a unique combination of features, including an interchangeable counter-balanced, self-contained power module130, a unitary, tightly-coupled (e.g., relatively short wheel base124) base104with a plurality of maneuverable wheels114,118, a single guide rail106, a constant force spring arrangement, and a novel ball spline driven actuator150in order to provide the racking device102with many advantages. Among them are that it is easy and quick to set-up, portable, easy to maneuver, compatible with a variety of different electrical apparatus, and requires minimal programming. Specifically, unlike known racking devices (e.g., racking device2ofFIG. 1) which require complex profiling of electrical apparatus including programming the exemplary racking device102efficiently and effectively performs a verity of racking operations on a wide array of different electrical apparatus, without requiring operator programming.

Additional features, such as the aforementioned wheels1118which are suitable for uneven or rough terrain, and convenient features such as an integrated storage locker208(FIG. 3) at the base104for storing, for example various end effectors, and a latch (not shown) for locking the power module in the lowest position during shipping or transportation, further add to the utility and efficiency of the racking device of the invention.