Patent Publication Number: US-10777979-B2

Title: Motorized racking assembly having a drive assembly disposed in a space below and between housing assembly rails

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of, and claims priority to, U.S. patent application Ser. No. 15/221,660, filed Jul. 28, 2016, which is a continuation of, and claims priority to, U.S. patent application Ser. No. 14/197,331, filed Mar. 5, 2014, entitled MOTORIZED RACKING ASSEMBLY, the contents of each are incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an electrical switching apparatus and, more specifically, to a motorized racking assembly for an electrical switching apparatus. 
     Background Information 
     An electrical switching apparatus, in an exemplary embodiment, includes a housing assembly a number of electrical components and at least one bus assembly. The housing assembly is structured to insulate and enclose the other components. The number of electrical components include, but are not limited to, voltage transformers, control power transformers, fuses, batteries, and other electrical components with the exception of circuit breakers. The bus assembly includes a conductive bus that is further coupled to, and in electrical communication with, an external line bus or a load bus. Within the housing assembly is a contact assembly which is fixed to the housing assembly. At least one electrical component includes a movable contact assembly. The electrical components are disposed on a movable carriage. The carriage moves between a first and second position. When the carriage is in the first position, the electrical component movable contact assembly is spaced from, and not in electrical communication with, the housing assembly contact assembly. When the carriage is in the second position, the electrical component movable contact assembly is coupled to, and in electrical communication with, the housing assembly contact assembly. These components are withdrawn to isolate them from the voltage source thus creating a safe work environment for the user to perform maintenance or inspections. Movement of the carriage is done manually. 
     Manual movement of the carriage has several disadvantages. For example, the electrical switching apparatus may be heavy requiring a technician to exert considerable force to move the carriage. Further, a technician must be at the location of the electrical switching apparatus. In addition, the technician may accidentally force the carriage into the second position when components are misaligned. There is, therefore a need for a racking assembly for an electrical apparatus that overcomes these disadvantages. 
     SUMMARY OF THE INVENTION 
     These needs, and others, are met by at least one embodiment of the disclosed concept which provides a racking assembly for an electrical apparatus including a movable carriage assembly and a drive assembly. The movable carriage assembly is sized to fit within a housing assembly and is structured to be moved between a first position and a second position. The carriage assembly is further structured to support at least one electrical component. The drive assembly includes a motor assembly and a positioning assembly. The motor assembly is structured to impart movement to said positioning assembly. The motor assembly is coupled to said positioning assembly. The positioning assembly is structured to impart movement to said carriage assembly and to move said carriage assembly from said first position to said second position. The positioning assembly coupled to said carriage assembly. In this configuration, the racking assembly is structured to move the carriage, and therefore the electrical apparatus, between the first and second positions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full understanding of the disclosed and claimed concept can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which: 
         FIG. 1  is a schematic side view of an electrical switching apparatus with a carriage assembly in a first position. 
         FIG. 2  is a schematic side view of an electrical switching apparatus with a carriage assembly in a second position. 
         FIG. 3  is a schematic side view of an alternate electrical switching apparatus with a carriage assembly in a first position. 
         FIG. 4  is a schematic side view of an alternate electrical switching apparatus with a carriage assembly in a second position. 
         FIG. 5  is a partial side view of an electrical switching apparatus with a carriage assembly in a first position. 
         FIG. 6  is a partial side view of an electrical switching apparatus with a carriage assembly in a second position. 
         FIG. 7  is a side cross-sectional view showing a number of stacked carriage assemblies. 
         FIG. 8  is an isometric view of a drive assembly.  FIG. 8A  is a detail view of the manual drive assembly. 
         FIG. 9  is another isometric view of a drive assembly. 
         FIG. 10  is a partial isometric view of a racking assembly. 
         FIG. 11  is a partial rear view of a racking assembly. 
         FIG. 12  is a detail view of a manual override assembly. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As used herein, the singular form of “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. 
     As used herein, the term “number” means one or an integer greater than one (i.e., a plurality). 
     As used herein, a “limited number” means one or more of a larger set. For example, a “number” wheels on a vehicle includes four wheels; a “limited number” of wheels means at least one but less than four. 
     As used herein, the statement that two or more parts or components are “coupled” shall mean that the parts are joined or operate together either directly or indirectly, i.e., through one or more intermediate parts or components, 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 so as to move as one while maintaining a constant orientation relative to each other. Accordingly, when two elements are coupled, all portions of those elements are coupled. A description, however, of a specific portion of a first element being coupled to a second element, e.g., an axle first end being coupled to a first wheel, means that the specific portion of the first element is disposed closer to the second element than the other portions thereof Further, an object resting on another object held in place only by gravity is not “coupled” to the lower object unless the upper object is otherwise maintained substantially in place. That is, for example, a book on a table is not coupled thereto, but a book glued to a table is coupled thereto. 
     As used herein, a “coupling assembly” includes two or more couplings or coupling components. The components of a coupling or coupling assembly are generally not part of the same element or other component. As such, the components of a “coupling assembly” may not be described at the same time in the following description. Further, a “removable coupling assembly” is a coupling assembly wherein the components are easily separated, such as, but not limited to a nut and bolt. 
     As used herein, a “coupling” is one element of a coupling assembly. That is, a coupling assembly includes at least two components, or coupling components, that are structured to be coupled together. It is understood that the elements of a coupling assembly are compatible with each other. For example, in a coupling assembly, if one coupling element is a snap socket, the other coupling element is a snap plug. 
     As used herein, the statement that two or more parts or components “engage” one another shall mean that the parts exert a force against one another either directly or through one or more intermediate parts or components. 
     As used herein, the word “unitary” means a component is created as a single piece or unit. That is, a component that includes pieces that are created separately and then coupled together as a unit is not a “unitary” component or body. 
     As used herein, “correspond” indicates that two structural components are sized and shaped to be similar to each other and may be coupled with a minimum amount of friction. Thus, an opening which “corresponds” to a member is sized slightly larger than the member so that the member may pass through the opening with a minimum amount of friction. This definition is modified if the two components are said to fit “snugly” together or “snuggly correspond.” In that situation, the difference between the size of the components is even smaller whereby the amount of friction increases. If the element defining the opening and/or the component inserted into the opening are made from a deformable or compressible material, the opening may even be slightly smaller than the component being inserted into the opening. This definition is further modified if the two components are said to “substantially correspond.” “Substantially correspond” means that the size of the opening is very close to the size of the element inserted therein. That is, not so close as to cause substantial friction, as with a snug fit, but with more contact and friction than a “corresponding fit,” i.e. a “slightly larger” fit. 
     As used herein, “associated” means that the elements are part of the same assembly and/or operate together, or, act upon/with each other in some manner For example, an automobile has four tires and four hub caps. While all the elements are coupled as part of the automobile, it is understood that each hubcap is “associated” with a specific tire. 
     Directional phrases used herein, such as, for example and without limitation, top, bottom, left, right, upper, lower, front, back and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein. 
     As used herein, “structured to [verb]” means that the identified element or assembly has a structure that is shaped, sized, disposed, coupled and/or configured to perform the identified verb. For example, a member that is “structured to move” is movably coupled to another element and includes elements that cause the member to move or the member is otherwise configured to move in response to other elements or assemblies. 
     As used herein, “structured to [verb]” when used in relation to a software module or code, means that the module/code includes executable computer instructions, code, data, or similar elements that perform the identified task. 
     As used herein, and when used in reference to communicating data or a signal, “in electronic communication” includes both hardline and wireless forms of communication. 
     As used herein, “in electric communication” means that a current passes between the identified elements. 
     As shown in  FIGS. 1-6 , an electrical switching apparatus  10  includes a housing assembly  12 , a number of electrical components  20 , and a number of racking assemblies  30 . The housing assembly  12  includes a number of sidewalls  13  that define an enclosed space  14 . In an exemplary embodiment, the sidewalls  13  include a generally planar bottom sidewall  13 ′, a generally planar back sidewall  13 ″, a movable front cover  13 ″′, and two lateral sidewalls  13 ″″. The housing assembly  12  further includes a number of rails  16 . As shown, the rails are disposed in generally parallel pairs of rails  16 . In an exemplary embodiment, the rails  16  are planar members extending generally perpendicular and upwardly from the bottom sidewall  13 ′. Further, the rails  16  extend generally in a front-to-back direction in the housing assembly  12 . In an alternate embodiment, there are a number of rails  16  in each housing assembly  12 . The rails  16  are disposed in generally parallel pairs with the lowest pair extending generally perpendicular and upwardly from the bottom sidewall  13 . The upper pairs of rails  16  are coupled to the lateral sidewalls  13 ″ of the housing assembly  12 . In this configuration, multiple sets of electrical components  20  and racking assemblies  30  may be disposed in the housing assembly  12 . 
     The housing assembly  12  also includes a bus assembly  17 . The bus assembly  17  includes, among other components, a contact assembly  18 . The housing assembly contact assembly  18  is structured to be coupled to another contact assembly. In an exemplary embodiment, the housing assembly contact assembly  18  includes two resilient fingers  19  that are biased toward each other. The housing assembly contact assembly  18  is in electrical communication with a line or load bus. The housing assembly contact assembly  18  is coupled, or fixed, to the back sidewall  13 ″. 
     The number of electrical components  20  vary depending upon the nature of the electrical switching apparatus  10 . In an exemplary embodiment, and as used herein, the number of electrical components  20  include voltage transformers, control power transformers, fuses, and batteries, but does not include circuit breakers. That is, circuit breakers are specifically excluded from the definition of “electrical components.” The number of electrical components  20 , or a limited number of the number of electrical components  20 , are in electrical communication with each other. At least one of the number of electrical components  20  includes a movable contact assembly  22 . The movable contact assembly  22  is structured to be coupled to, and placed in electrical communication with, the housing assembly contact assembly  18 . In an exemplary embodiment, the movable contact assembly  22  includes a planar member  24  that is structured to fit between the fingers  19  of the housing assembly contact assembly  18 . The movable contact assembly  22  is in electrical communication with at least one of the number of electrical components  20 . 
     The racking assemblies  30  are substantially similar and therefore, only one will be described. The racking assembly  30  includes a movable carriage assembly  40  and a drive assembly  50 , shown in  FIG. 8 . The carriage assembly  40  includes a body  42  and a number of wheels  44 . The carriage assembly body  42  is sized to fit within said housing assembly enclosed space  14 . In an exemplary embodiment, the carriage assembly body  42  is generally rectangular, generally planar and disposed generally horizontally. That is, the carriage assembly body  42 , in an exemplary embodiment, includes a generally planar upper surface  46  and a generally planar lower surface  48 . The carriage assembly body  42  is structured to support the number of electrical components  20 , or a limited number of the number of electrical components  20 . That is, as shown in  FIGS. 1 and 2 , the carriage assembly body  42 , in one embodiment, supports all the electrical components  20  and the electrical components  20  move therewith. Alternatively, as shown in  FIGS. 3 and 4 , the carriage assembly body  42  supports a limited number of electrical components  20  including the movable contact assembly  22 . In this embodiment, the movable contact assembly  22  is coupled to, and in electrical communication with, the unsupported electrical components  20  via a conductor  23 . 
     Further, the carriage assembly body  42  is structured to be moved between a first position and a second position, as shown in  FIGS. 5 and 6 . In an exemplary embodiment, the carriage assembly wheels  44  are rotatably coupled to the carriage assembly body  42 . In an exemplary embodiment, there are four carriage assembly wheels  44  which are disposed in opposing pairs on the lateral sides of the carriage assembly body  42 . The carriage assembly wheels  44  are structured to travel over the housing assembly rails  16 . As used herein, the carriage assembly body  42  defines a “path of travel” between the carriage assembly body  42  first position and second position. That is, as used herein, the carriage assembly body  42  “path of travel” is defined by space occupied by the movable carriage assembly  40  and the number of electrical components  20  disposed thereon as the carriage assembly body  42  moves between the first position and second position. 
     As shown in  FIG. 7 , the housing assembly  12  is, in an exemplary embodiment, structured to enclose a number of racking assemblies each with a movable carriage assembly  40  supporting electrical components  20 . The movable carriage assemblies  40  are disposed in a stacked configuration, i.e., one carriage assembly  40  disposed above another. As discussed in detail below, the drive assembly  50  has a thin profile that allows the drive assembly  50  to be disposed below the associated carriage assembly  40  in the space defined by the rails  16  ( FIG. 10 ). That is, each drive assembly  50  is coupled to, directly coupled to, or fixed to the housing assembly  12  at a location below and between the rails  16  used by the associated carriage assembly  40 . 
     The drive assembly  50 , shown in  FIGS. 8 and 9 , includes a motor assembly  60  and a positioning assembly  80 . In an exemplary embodiment, the drive assembly  50  further includes a manual override assembly  120 , a control assembly  150 , and a lock assembly  230 . The motor assembly  60  is structured to impart movement to the positioning assembly  80 . In one exemplary embodiment, the motor assembly  60  is coupled, directly coupled, or fixed to the carriage assembly body  42 . In an alternate embodiment, the motor assembly  60  is coupled, directly coupled, or fixed to the housing assembly  12 . The motor assembly  60 , in an exemplary embodiment, is an electric motor  62  that includes a rotating output shaft  64  and a power line  66 . The motor assembly  60  is coupled to the positioning assembly  80 . In an exemplary embodiment, the motor assembly  60  is structured to cause the output shaft  64  to rotate in two directions, i.e. clockwise and counter clock-wise. In an exemplary embodiment, the output shaft  64  is operatively coupled to the positioning assembly  80 . As used herein, “operatively coupled” means that motion in one element is transferred to another element; the motion, however, may be altered, e.g. a rotational motion may be transformed into a linear motion. 
     The positioning assembly  80  is structured to impart movement to the carriage assembly  40  and to move the carriage assembly  40  from the first position to the second position. That is, the positioning assembly  80  is structured to position the carriage assembly  40  at a selected location in the housing assembly  12 . The positioning assembly  80  is coupled, directly coupled, removably coupled, or fixed to the carriage assembly body  42  and/or the housing assembly  12 . In an exemplary embodiment, the positioning assembly  80  is disposed between the carriage assembly body  42  and the housing assembly  12  thereby coupling the two elements. The positioning assembly  80  is structured to cooperate with the motor assembly  60 . That is, the positioning assembly  80  is structured to convert motion generated by the motor assembly  60  into a motion that imparts movement to the carriage assembly  40 . 
     For example, in one embodiment, not shown, the positioning assembly  80  includes a worm gear, a toothed rack, and low friction sliders (none shown). The rack is fixed to the carriage assembly  40 . The motor assembly  60  is fixed to the housing assembly  12 . The worm gear is fixed to the output shaft  64  and is operatively coupled to the rack. The low friction sliders are coupled to the bottom side of the carriage assembly body  42 . In this configuration, when the motor assembly  60  is actuated, the worm gear rotates and engages the rack. The rack, and therefore the carriage assembly body  42  moves in response to the motion of the worm gear. In another embodiment, also not shown, the carriage assembly wheels  44  are operatively coupled to the drive assembly  50 , e.g. by a drive shaft (not shown). 
     In an exemplary embodiment, as shown, a positioning assembly  80  includes a support assembly  90 , a number of lead screws  92 , a number of drive blocks  94 , and a transmission assembly  96 . The support assembly  90  includes a generally planar member  100  and a number of generally vertical sidewalls  102 . The support assembly  90  generally defines the height of the drive assembly  50 . That is, as used herein, “generally defines the height of the drive assembly” means the height of the closely coupled elements and expressly does not include the height/position of the sensors  156  or the manual override assembly  120 . The support assembly  90  has a height of between about 1.5 inches and 3.5 inches, or about 2.5 inches. 
     The support assembly planar member  100  defines a number of drive channels  104 . In an exemplary embodiment, the support assembly planar member  100  is generally rectangular and is sized to be disposed in the housing assembly  12 . The vertical sidewalls  102  are coupled, directly coupled or fixed to the support assembly planar member  100  and extend generally perpendicular to and downwardly therefrom. The support assembly vertical sidewalls  102  are further coupled, directly coupled or fixed to the housing assembly bottom sidewall  13 ′. 
     In an exemplary embodiment, the drive channels  104  are elongated slots in the support assembly planar member  100 . Further, when the support assembly planar member  100  is disposed in the housing assembly  12 , the drive channels  104  extend generally in a front-to-back direction in the housing assembly  12 . Each lead screw  92  is disposed in an associated drive channel  104 . In an exemplary embodiment, there are two lead screws  92  and two drive channels  104 . The two drive channels  104  are disposed near the lateral sides of the support assembly planar member  100 . Each lead screw  92  is rotatably coupled to the support assembly planar member  100 . 
     Each drive block  94  is sized to loosely correspond to the width of an associated drive channel  104 . In an exemplary embodiment, each drive block  94  is a generally parallelepiped body  98  that defines a threaded passage (not shown). Each threaded passage is sized to correspond to the associated lead screw  92 . Each drive block  94  is movably coupled to the associated lead screw  92 . That is, each lead screw  92  is threaded through an associated drive block  94 . In this configuration, each drive block  94  cannot rotate substantially within the associated drive channel  104 , but can move freely along the associated lead screw  92 . Thus, rotation of each lead screw  92  causes the associated drive block  94  to move along the lead screw  92  between a first position and second position. 
     The transmission assembly  96  is operatively coupled to the motor assembly  60  as well as to each lead screw  92 . In an exemplary embodiment, the transmission assembly  96  includes a tension member  110  such as, but not limited to, one of a belt  112 , toothed belt (not shown), or a chain (not shown). The tension member  110  is operatively coupled to the motor assembly output shaft  64 . In an exemplary embodiment, the motor assembly output shaft  64  has an axis of rotation that is generally parallel to, and generally in the same plane as, the axis of rotation of the two lead screws  92 . The tension member  110  is also operatively coupled to both lead screws  92 . Thus, rotational motion is transferred from the motor assembly  60  to the lead screws  92  via the tension member  110 . As noted above, rotational motion of the lead screws  92  cause the drive blocks  94  to move along the lead screws  92 . It is understood that the rotation of the lead screws  92  causes the drive blocks  94  to move in one direction and an opposite rotation of the lead screws  92  causes the drive blocks  94  to move in the other direction. 
     The drive assembly  50  is assembled as follows. The motor assembly  60  is coupled, directly coupled, or fixed to the support assembly  90  with the axis of rotation of the motor assembly output shaft  64  having an axis of rotation that is generally parallel to, and generally in the same plane as, the axis of rotation of the two lead screws  92 . The tension member  110  is operatively coupled to both the motor assembly output shaft  64  and the lead screws  92 . The support assembly  90  is then coupled, directly coupled, or fixed to the housing assembly  12 . In an exemplary embodiment, the support assembly  90  is disposed between, but below, or partially below, a pair of rails  16 . That is, because the drive assembly  50  has a low profile, the drive assembly  50  occupies a minimal space in the housing assembly  12  and is disposed outside the carriage assembly body  42  path of travel. The support assembly  90  is, in an exemplary embodiment, disposed so that the lead screw  92  extends generally front-to-back within the housing assembly  12 . 
     In this configuration, the carriage assembly  40  is structured to be coupled to the positioning assembly  80 . In an exemplary embodiment, the carriage assembly body  42  is coupled, directly coupled, fixed, or selectively coupled to the drive blocks  94 . In this configuration, the carriage assembly body  42  moves with the drive blocks  94  between a first position and second position. The number of electrical components  20  disposed on the carriage assembly body  42  move therewith. This includes the movable contact assembly  22  which moves between a separated, first position, wherein the housing assembly contact assembly  18  and the movable contact assembly  22  are not in electrical communication, and a coupled, second position, wherein the housing assembly contact assembly  18  and the movable contact assembly  22  are in electrical communication. In an exemplary embodiment, the housing assembly contact assembly  18  is disposed on the back sidewall  13 ″; thus, the movable contact assembly  22  separated, first position is when the carriage assembly  40  is disposed closer to the forward side of the housing assembly  12 , and, the movable contact assembly  22  coupled, second position is when the carriage assembly  40  is disposed closer to the back sidewall  13 ″. 
     In an exemplary embodiment, the carriage assembly body  42  is selectively coupled to the drive blocks  94 . That is, the manual override assembly  120 , shown in 
       FIGS. 10-12  allows for the carriage assembly body  42  and the drive blocks  94  to be selectively decoupled. In this configuration, a user decouples the carriage assembly  40  and the drive assembly  50  so as to manually move the carriage assembly body  42  between the carriage assembly body  42  first and second positions with the use of the drive assembly  50 . Thus, in an exemplary embodiment, the manual override assembly  120  includes a selectively couplable coupling assembly  122 . 
     In an exemplary embodiment, the selectively couplable coupling assembly  122  includes a number of first coupling components  124  and a number of second coupling components  126 . Each selectively couplable coupling assembly first coupling component  124 , hereinafter “manual override first coupling component  124 ,” is coupled to a lead screw  92 . In the embodiment shown, each manual override first coupling component  124  is a drive block  94 . Each selectively couplable coupling assembly second coupling component  126 , hereinafter “manual override second coupling component  126 ,” is coupled to the carriage assembly  40 . In an exemplary embodiment, each manual override second coupling component  126  is a bracket latch assembly  130 . 
     As shown in  FIG. 12 , a bracket latch assembly  130  includes a mounting  132 , a bracket latch member  134  and a biasing device  136 . The bracket latch assembly mounting  132  is coupled, directly coupled, or fixed to the carriage assembly  40 . The bracket latch member  134  includes a body  138  with a latch end  140 . The bracket latch member body latch end  140  is structured to bracket (as used herein the verb “bracket” means to partially encompass”) a portion of the manual override first coupling component  124 , i.e. a drive block  94 . In an exemplary embodiment, the bracket latch member body latch end  140  is a rectangular cutout  142  sized to correspond to the drive block  94 . That is, in an exemplary embodiment, the bracket latch member body  138  is generally planar and is disposed in a plane that is generally aligned with a lead screw  92  axis of rotation. In this configuration, the bracket latch member body latch end  140  extends over the front and back side of the drive block  94 . Thus, when the drive block  94  moves, the motion is transferred to the bracket latch member body  138  as well as the carriage assembly  40 . 
     That is, the bracket latch member body  138  is movably coupled to the bracket latch assembly mounting  132 . In an exemplary embodiment, the bracket latch member body  138  is structured to translate relative to the bracket latch assembly mounting  132 . Further, the bracket latch assembly biasing device  136 , which includes, but is not limited to, a compression spring  144  is disposed between the bracket latch member body  138  and the bracket latch assembly mounting  132 . In this configuration, the bracket latch member body  138  is structured to move between a first, engaged position, wherein the bracket latch member body  138  engages an associated drive block  94 , and a second, disengaged position, wherein the bracket latch member body  138  does not engage an associated drive block  94 . Further, the bracket latch assembly biasing device  136  biases the bracket latch member body  138  toward the first position. Further, the bracket latch member body  138 , in an exemplary embodiment, includes a finger tab  146  that is structured to assist a user in moving the bracket latch member body  138  between positions. 
     The drive device control assembly  150  is structured to allow remote control and monitoring of the drive assembly  50 , as shown in  FIG. 8  (all drive device control assembly elements shown schematically). In an exemplary embodiment, the control assembly  150  includes a control circuit  152 , an output assembly  154  and a number of sensors  156 . Further, the control assembly  150  includes a data storage device  158  and an input assembly  160 . The control circuit  152  includes hardware and software (shown schematically) such as, but not limited to a programmable logic circuit and memory devices, structured to engage and disengage power to the motor assembly  60 , to monitor the sensors  156 , discussed below, provide output to the output assembly  154  and to receive and respond to input from the input assembly  160 . The control circuit  152  is in electronic communication with the motor assembly  60  and is structured to control, i.e. turn on/off and control the power level to, the motor assembly  60 . The control circuit  152  is further structured to control the direction of the motor assembly  60  output. 
     The control assembly input assembly  160  is structured to receive input from the sensors  156  as well as from a user. The input assembly  160  includes a control panel (not shown) that is remote from the housing assembly  12 . The control assembly output assembly  154  is structured to provide information to the user. The control assembly output assembly  154  includes, but is not limited to, a display on the remote control panel. The control assembly output assembly  154  also includes indicators, such as, but not limited to lights, that are illuminated under certain condition, e.g. the carriage assembly  40  located in the second position. 
     Each sensor  156  is structured to detect a selected characteristic, to generate data representative of that characteristic, and to provide a signal representing that data. Further, each sensor  156  is in electronic communication with the control circuit  152 . That is, each sensor  156  signal is communicated to the control circuit  152 . For example, the sensors  156  include, but are not limited to, a current sensor  156 ′ and a torque sensor  156 ″. The current sensor  156 ′ is coupled to, and structured to detect the current within, the motor assembly power line  66 . The torque sensor  156 ″ is coupled to, and structured to detect the torque within, the motor assembly output shaft  64 . In this configuration, the control assembly  150  can detect an increase in the power to, or torque within the motor assembly  60 . Such increases may indicate the carriage assembly  40 , or other element, has become jammed or stuck. 
     That is, in an exemplary embodiment, the control assembly data storage device  158  includes data representing an acceptable power draw profile. The control circuit  152  is structured to compare data from the current sensor  156 ′ to the acceptable power draw profile and, if the data from the current sensor  156 ′ deviates from the acceptable power draw profile by a first deviation, the control circuit  152  is structured to present an indication on the output assembly  154 . For example, when the current sensor  15 ′ detects an increased current, a warning light (not shown) is illuminated. Further, if the data from the current sensor  156 ′ deviates from the acceptable power draw profile by a second, greater deviation, the control circuit  152  is structured to terminate the operation of the motor assembly  60 . Similarly, an indication of increased torque may indicate a jammed carriage assembly  40  and may be processed by the control circuit  152  in a similar manner. 
     The sensors  156  further include position sensors  156 ′″ and external sensors  156 ″″. The position sensors  156 ′″ are coupled to at least one of the carriage assembly  40  or the housing assembly  12  and are structured to determine the position of the carriage assembly  40  relative to the housing assembly  12 . In an exemplary embodiment, the position sensors  156 ′″ are disposed along the rails  16  and are structured to indicate the position of the carriage assembly  40  relative to the rails  16 . This includes, but is not limited to, sensors that indicate when the carriage assembly  40  is in the first and second positions. The control circuit  152  is structured to provide an indication of the carriage assembly  40  position on the output assembly  154 . The external sensors  156 ″″ are structured to measure characteristics of the electrical components such as, but not limited to, current passing through the electrical components. 
     In an exemplary embodiment, the drive assembly  50  further includes a manual drive assembly  170 . The manual drive assembly  170  is structured to impart movement to the positioning assembly  80  manually, i.e. without engaging the motor assembly  60 . In an exemplary embodiment, the manual drive assembly  170  includes a mounting  172  and a coupling assembly  174  including a first coupling component  176  and a second coupling component  178 . As shown in  FIG. 8 , and in an exemplary embodiment, the manual drive assembly mounting  172  includes an opening  180  and a bracket  182 . The manual drive assembly mounting opening  180  is located in a support assembly vertical sidewall  102  at a location aligned with the axis of rotation of a lead screw  92 . That is, the axis of rotation of a lead screw  92  extends generally through the center of the manual drive assembly mounting opening  180 . The manual drive assembly mounting bracket  182 , in an exemplary embodiment, includes a generally U-shaped body  184  that also defines an opening  186 . The manual drive assembly mounting opening  180  and the manual drive assembly mounting bracket opening  186  are both generally circular. 
     The manual drive assembly first coupling component  176  is, in an exemplary embodiment, a unitary extension of a lead screw  92  having a portion that is a non-circular shape. That is, the lead screw  92  includes an extension  190  sized to extend beyond the associated drive channel  104 . The lead screw extension  190  includes a proximal portion  192  and a distal portion  194 . The lead screw extension proximal portion  192  is disposed adjacent the lead screw  92 , and in an exemplary embodiment, is unitary therewith. The lead screw extension distal portion  194  has a non-circular cross-sectional shape. In an exemplary embodiment, the lead screw  92  extension distal portion  194  has the same diameter as the minor diameter of the lead screw  92  but with opposing sides milled flat. Thus, the manual drive assembly first coupling component  176  is, in an exemplary embodiment, a generally oval shaped portion, i.e. the lead screw extension distal portion  194 . 
     The manual drive assembly second coupling component  178  is structured to be rotatably coupled to the support assembly  90  and fixed to the manual drive assembly first coupling component  176 . In an exemplary embodiment, the manual drive assembly second coupling component  178  is a shaped body  200  defining a shaped passage  202 . The manual drive assembly second coupling component shaped body  200 , in an exemplary embodiment, has an outer shape that is structured to be engaged by a hand tool, such as, but not limited to a wrench. Thus, in an exemplary embodiment, the manual drive assembly second coupling component shaped body  200  has a hexagonal shape similar to a six-sided nut. The manual drive assembly second coupling component shaped passage  202  is sized and shaped to substantially correspond to the lead screw extension  190 . That is, the manual drive assembly second coupling component shaped passage  202  includes first portion  204  and a second portion  206 . The passage first portion  204  has a substantially circular cross-sectional shape with a diameter substantially corresponding to the diameter of the lead screw extension proximal portion  192 . The passage second portion  206  substantially corresponds to the shape of the lead screw extension distal portion  194 . That is, in an exemplary embodiment, the passage second portion  206  includes two opposed flat surfaces. 
     Further, the second coupling component shaped body  200  includes a circumferential channel  210 . In an exemplary embodiment, the circumferential channel  210  is disposed about the passage first portion  204 . The circumferential channel  210  is sized to correspond to the thickness of the support assembly vertical sidewall  102  that defines the manual drive assembly mounting opening  180 . 
     The manual drive assembly  170  is assembled as follows. The manual drive assembly second coupling component  178  is disposed over the manual drive assembly first coupling component  176 . That is, the second coupling component shaped body  200  is coupled to the lead screw extension  190  by passing the lead screw extension  190  through the shaped passage  202 . In this configuration, the second coupling component shaped body  200  is fixed to the lead screw extension  190 . That is, because the lead screw extension distal portion  194 , and because the passage second portion  206  substantially corresponds to the shape of the lead screw extension distal portion  194 , the manual drive assembly first and second coupling components  176 ,  178  cannot rotate relative to each other. 
     Further, the second coupling component shaped body circumferential channel  210  is disposed at the manual drive assembly mounting opening  180  with the support assembly vertical sidewall  102  extending into the second coupling component shaped body circumferential channel  210 . In this configuration, the manual drive assembly second coupling component  178  cannot move axially relative to the lead screw  92 , but is still free to rotate relative to the support assembly  90 . The manual drive assembly mounting bracket  182  is coupled, directly coupled, or fixed to the support assembly vertical sidewall  102  at a location aligned with the axis of rotation of a lead screw  92 . That is, the manual drive assembly mounting bracket opening  186  is generally centered along the axis of the lead screw  92 . 
     In this configuration, a user can couple a tool, such as, but not limited to a wrench, to the manual drive assembly second coupling component shaped body  200  and rotate the manual drive assembly second coupling component  178 . The rotational motion applied to the manual drive assembly second coupling component  178  is transferred to the manual drive assembly first coupling component  176  thereby causing the lead screw  92  to rotate. Further, the rotation of the lead screw  92  having the manual drive assembly  170  is transferred to the other lead screw  92  via the transmission assembly  96 . 
     The lock assembly  230  is structured to prevent the rotation of a lead screw  92 . In an exemplary embodiment, the lock assembly  230  includes a movable bolt (not shown) that is actuated by a key (not shown). The bolt is structured to move between a withdrawn, first position, wherein the bolt does not engage the lead screw  92 , and an extended, second position, wherein the bolt engages the lead screw. When the bolt engages the lead screw  92 , rotation of the lead screw  92  is prevented. 
     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.