Abstract:
The present invention is a compound motorized lift device facilitating the uninterrupted and nearly noiseless movement of a low-profile television. The invention is comprised of a base unit, an intermediate unit, and a support unit slidably disposed in a telescoping fashion in the described order. A pair of linearly extensible slides are fastened between base and intermediate units and between intermediate and support units. The intermediate unit is extended and retracted with respect to the base unit in a linear fashion via a motor driven screw. The support unit is extended and retracted in a linear fashion via a cable-pulley arrangement that couples motion by the intermediate unit in a likewise direction to the support unit.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   None. 
   FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   None. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention generally relates to a motorized lift. Specifically, the invention is a compound lift capable of extending a low-profile television from and retracting a low-profile television into a storage cabinet so as to provide volume efficient storage. 
   2. Description of the Related Art 
   Television design trends are now focused on low-profile devices including but not limited to plasma screens and LCD panels. Low-profile televisions maximize viewing area and minimize unit depth. However, designs are inherently less decorative, less stable, and heavier than conventional televisions. 
   Aesthetic and stability deficiencies of low-profile televisions are addressed by housing the television within a cabinet. In such applications, the low-profile television is extended from and retracted into the cabinet via a lift. 
   While lifts are known within the art, the height of such devices greatly exceeds that of the low-profile television. As such, cabinet dimensions are dictated by the lift envelope rather than by the size of the television thereby favoring volumetrically inefficient designs. Larger cabinets are less desirous in residential settings due to floor space constraints. Furthermore, such cabinets place the television at a height that is less than optimal for viewing conditions within residential settings. 
   What is currently required is a lift device that is compact and provides for the compact storage of a low-profile television. 
   What is required is a lift device capable of extending a low-profile television to a height conducive to residential applications. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a television lift device of telescoping design so as to provide for the compact storage of both lift and television. 
   A further object of the present invention is to provide a lift device of telescoping design so as to provide a viewing arrangement compatible with residential use. 
   The present invention is a compound motorized lift facilitating the uninterrupted and nearly noiseless movement of a low-profile television. The invention is comprised of a base unit, an intermediate unit, and a support unit slidably disposed in a telescoping fashion in the described order. A pair of linearly extensible slides are fastened between base and intermediate units and between intermediate and support units. The intermediate unit is extended and retracted from the base unit in a linear fashion via a motor driven screw. The support unit is extended and retracted in a linear fashion via a cable-pulley arrangement that couples movement of the intermediate unit to the support unit in a likewise direction. 
   The base unit is comprised of a plate of planar extent and a first pair of linearly extensible slides separately disposed and parallel. A linear slide is fastened to each length-wise flange along the base unit. 
   The support unit is comprised of a plate of planar extent and a second pair of linearly extensible slides separately disposed and parallel. A linear slide is fastened to each length-wise flange along the support unit. At least two support elements are adjustably fastened to the support unit so as to facilitate secured attachment of a low-profile display. 
   The intermediate unit is comprised of a plate of planar extent, a first pair of pulleys attached at one end, and a second pair of pulleys attached along a second end. First and second pairs of linearly extensible slides are separately fastened to the intermediate unit so as to allow movement between intermediate and base units and between support and intermediate units. 
   A reversible motor is fastened to the base unit and directly coupled to a drive screw. The drive screw is secured to the base unit so as to allow its rotation. The drive screw contacts the intermediate unit thereby imparting linear movement to the intermediate unit via rotation of the drive screw. The intermediate unit extends from and retracts relative to the base unit. The intermediate unit is disposed between base and support units when the compound lift is retracted. 
   A pair of cables are separately disposed and parallel about the drive screw. Cables are fastened to base and support units and slidably disposed about the intermediate unit via pulleys. Cables impart movement in a likewise direction to the support unit when the intermediate unit is extended and retracted. 
   In alternate embodiments, the compound lift device further comprises a limit switch fastened to the base unit and electrically connected to the reversible motor so as to control lift function. The limit switch is attached to a rod extending along the length of the base unit and parallel to the drive screw. The rod is attached to the base unit in a secured fashion thereby allowing for movement along its length. The rod has a mechanical stop to STOP and REVERSE the motor when the compound lift device is retracted and a mechanical stop to STOP and REVERSE the motor when the compound lift device is extended. 
   In yet other embodiments, the compound lift device further comprises a controller communicating with a rotary motion sensor so as to START, STOP and/or REVERSE the motor based upon the rotational history of the drive screw. 
   Several advantages are offered by the present invention. The invention minimizes cabinet size thereby reducing weight and cost. The invention enables both extension and retraction of a low-profile television in a smooth, stable, and nearly noiseless fashion. The invention facilitates greater height adjustability thereby accommodating a variety of viewing conditions. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which: 
       FIG. 1  is a perspective view of the present invention showing front of lift when completely retracted. 
       FIG. 2  is a perspective view of the present invention showing front of lift when completely extended. 
       FIG. 3  is a section view of support unit showing attachment of slides and c-channels about flanges along a central plate. 
       FIG. 4  is an enlarged view showing coupling between horizontal support element and c-channel. 
       FIG. 5  is an enlarged section view showing coupling between horizontal support element and c-channel. 
       FIG. 6  is an enlarged view showing coupling between horizontal rest and c-channel. 
       FIG. 7  is an enlarged section view showing coupling between horizontal rest and c-channel. 
       FIG. 8  is an elevation view of rear of support element showing attachment scheme fixing cables to bracket and thereby to support unit. 
       FIG. 9  is an enlarged view of bracket mounted to support unit showing cable secured between u-bolt and cable guide. 
       FIG. 10  is a perspective view showing rear of lift when extended having a first pair of slides attached between base and intermediate units and a second pair of slides attached between intermediate and support units. 
       FIG. 11  is a side elevation view of an exemplary linear slide. 
       FIG. 12  is a section view of slide from  FIG. 11  showing linear arrangement of inner and outer arms about ball bearings contacting and supported by a bearing support. 
       FIG. 13  is an elevation view of front of base unit showing motor attached to a screw lengthwise disposed along the base unit, a rod attached to a limit switch activated by a pair of stops along the rod length, and a pair of cables secured to a flange and contacting a pair of pulleys at one end of the intermediate unit. 
       FIG. 14  is an enlarged view showing a motor attached to a flange at one end of the base unit and coupled to a drive screw and a limit switch attached to the flange and coupled to a rod having mechanical stops to control motor function. 
       FIG. 15  is an enlarged view of front of the lower end of the intermediate unit and the upper end of the base unit showing drive screw coupled to a bushing attached to a flange along the intermediate unit. 
       FIG. 16  is a side section view showing drive screw attachment to a flange at the upper end of the base unit and a flange at the lower end of the intermediate element so that the intermediate unit is movable in a linear fashion when drive screw is rotated. 
       FIG. 17  is a rear elevation view showing the upper end of the intermediate unit having a pair of pulleys and cables thereon. 
       FIG. 18  is a schematic diagram showing cable ends attached to flanges along base unit, contact between cable and pulleys at both ends of intermediate unit, and attachment of cable to support unit so that linear movement of the intermediate unit via the drive screw causes likewise linear movement of the support unit via the cable-pulley arrangement. 
       FIG. 19  is an enlarged view of flange at the lower end of the base element and attachment of cable thereto. 
       FIG. 20  is an enlarged view of flange at upper end of the base element and attachment of cable thereto via an adjustable rod arrangement. 
       FIG. 21  is a block diagram of the motion control circuit for an exemplary embodiment. 
   

   REFERENCE NUMERALS 
   
       
         1  Compound lift 
         2  Base unit 
         3  Intermediate unit 
         4  Support unit 
         5  Horizontal support 
         6  Holes 
         7  Horizontal rest 
         8  Plate 
         9  Flange 
         10  C-channel 
         11  (A, B) Slides 
         12  Fastener 
         13  Inner locking plate 
         14  Fastener 
         15  Outer locking plate 
         16  Support bar 
         17  Outer locking plate 
         18  Inner locking plate 
         19  Fastener 
         20  Support plate 
         21  Bracket 
         22  (A, B) Cables 
         23  Stop 
         24  Cable fastener 
         25  U-bolt 
         26  Cable guide 
         27  Nut 
         28  Fastener 
         29  Ball bearing 
         30  Bracket 
         31  Outer arm 
         32  Bearing support 
         33  Inner arm 
         34  Drive screw 
         35  Flange 
         36  Motor 
         37  Limit switch 
         38  Rod 
         39  Lower stop 
         40  Upper stop 
         41  U-shaped bracket 
         42  Fastener 
         43  Coupler 
         45  Nut 
         46  (A, B) Pulleys 
         47  Flange 
         48  First bushing 
         49  Fastener 
         50  Flange 
         51  Stiffener 
         52  Plate 
         53  Flange 
         54  Second bushing 
         55  Threaded connector 
         57  Flat 
         58  Plate 
         59  T-shaped connector 
         60  Nut 
         61  Spring 
         62  Flange 
         63  First cable end 
         64  Second cable end 
         66  Wire 
         70  Low-profile display 
         100  Transformer 
         101  Socket 
         102  Television socket 
         103  Remote control receiver 
         104  Remote control transmitter 
         105  Switch 
         106  Controller 
         107  Manual control 
         108  Rotary motion sensor 
     
  
   DESCRIPTION OF THE INVENTION 
   Referring now to  FIG. 1 , an exemplary embodiment of the present invention, namely a compound lift  1  capable of extending and retracting a low-profile display  70 , is shown in its retracted position wherein a support unit  4 , an intermediate unit  3 , and a base unit  2  of comparable lengths are arranged in a telescoping-like fashion so as to conceal the intermediate unit  3  behind support unit  4  and base unit  2  behind intermediate unit  3 .  FIG. 2  shows the same compound lift  1  having both support unit  4  and intermediate unit  3  extended from the base unit  2 . The present invention may be mechanically attached to a storage cabinet via methods and techniques understood in the art. 
   A variety of application are possible for the present invention. For example, the compound lift  1  may raise a low-profile display  70  above or lower a low-profile display  70  below a cabinet in a vertical fashion. Likewise, the compound lift  1  may extend a low-profile display  70  in a horizontal fashion from a floor cabinet or wall mounted cabinet. Therefore, reference to top, bottom, upper, lower, upward and downward are for descriptive purposes only and not intended to limit application of the present invention. Fasteners are defined to include screws, bolts, rivets, and other similar devices understood in the art. 
   Referring again to  FIG. 1 , the support unit  4  is shown having a pair of horizontal supports  5  and an optional pair of horizontal rests  7  fastened thereto. It is preferred that the horizontal supports  5  have a plurality of holes  6  along their length to accommodate a variety of mounting configurations for commercially available low-profile displays  70 . 
   Referring now to  FIG. 3 , the support unit  4  is comprised of a planar disposed plate  8  having a flange  9  along both edges parallel to the length of the plate  8 . The plate  8  may be composed of a metal and the flanges  9  formed via conventional metal forming techniques. A slide  11 A is mounted along the inside and a c-channel  10  mounted along the outside of the flange  9  parallel to the slide  11 A. Slide  11 A and c-channel  10  are secured to the flange  9  via a plurality of fasteners  12 . The slide  11 A is attached to the flange  9  so as to allow the slide  11 A to function in an extendable and retractable fashion. 
   Referring now to  FIGS. 4–5 , a horizontal support  5  is shown attached to the c-channel  10 . An exemplary horizontal support  5  is comprised of a support bar  16  having a pair of outer locking plates  15  attached thereto, either mechanically fastened or welded, in a perpendicular arrangement. While the outer locking plate  15  may be rectangular shaped, it is preferred to have the outer locking plate  15  angled with respect to the support plate  16 , as shown in  FIG. 4 . An inner locking plate  13  is placed within the c-channel  10 , as shown in  FIG. 5 . Inner locking plate  13  and outer locking plate  15  are co-located along the length of the c-channel  10  and contact the c-channel  10  in a compressive fashion when fastener  14  is threaded through a hole through the inner locking plate  13 . The described arrangement fixes the horizontal support  5  to the c-channel  10 , however, allows adjustment to the location of the horizontal support  5  along the length of the c-channel  10 . 
   Referring now to  FIGS. 6–7 , an optional horizontal rest  7  is shown attached to one end of a c-channel  10 . The horizontal rest  7  is preferred when additional support is required to secure a low-profile display  70  onto the support unit  4 . The exemplary horizontal rest  7  shown in  FIG. 7  is comprised of a support plate  20  fastened, welded or otherwise fixed to an outer locking plate  17  in a perpendicular arrangement. The support plate  20  may have one or more holes  6  so as to allow mechanical attachment to a low-profile display  70 . The support plate  20  should contact the end of the c-channel  10  so as to prevent rotation of the horizontal rest  7  when supporting load from a low-profile display  70 , as represented in  FIG. 6 . The outer locking plate  17  and an inner locking plate  18  are co-located adjacent to the end of the c-channel  10  and contact the c-channel  10  in a compressive fashion when fastener  19  is engaged through a hole through the inner locking plate  17 . The described arrangement fixes the horizontal rest  7  to the c-channel  10 , however, allows for its adjustment and removal. 
   Referring now to  FIG. 8 , the rear of the support unit  4  is shown having a bracket  21  mechanically fastened or welded thereto. The bracket  21  facilitates the fastening of a pair of separately disposed but parallel cables  22 (A, B) to the support unit  4  via cable fasteners  24 . The dual cable  22 A arrangement allows for extension and retraction of the support unit  4  via extension and retraction of the intermediate unit  3 . While bracket  21  location is design dependent, the extended height of the support unit  4  above the intermediate unit  3  is directly related to the distance between bracket  21  and top of support unit  4 . 
   Cables  22 (A, B) are typically elements having a small cross section, yet sufficiently flexible to allow for small radius bends and sufficiently strong to support the weight of a low-profile display  70 . For example, it was preferred to have a cable  22 A composed of a bundled arrangement of thin wires. In yet other embodiments, the cable  22 A was composed of a flexible metal chain. 
   Referring now to  FIG. 9 , an exemplary attachment scheme for cable  22 B to plate  8  comprising the support unit  4  is shown in detail. While various hardware schemes are possible, adequate interlock between cable  22 B and bracket  21  was achieved by securing the cable  22 B between a cable guide  26  having a channel conforming to the shape of the cable  22 B and a u-bolt  25 . The u-bolt  25  was fastened to bracket  21  and cable guide  26  through a pair of holes separate disposed about the cable  22 B passing through each component. A nut  27  was threaded onto the both ends of the u-bolt  25  thereby providing the compression required to secure cable  22 B to cable fastener  24  and thereafter to bracket  21 . Identical attachment schemes are used for cable  22 A. 
   Referring now to  FIG. 10 , the present invention is shown with intermediate unit  3  extended from base unit  2  and support unit  4  extended from intermediate unit  3 . Extension and retraction between intermediate unit  3  and support unit  4  and between base unit  2  and intermediate unit  3  is achieved via a pair-wise arrangement of linear slides  11 A and  11 B, respectively. Each slide  11 (A, B) is comprised of an outer arm  31  and an inner arm  33 . An inner arm  33  is fastened via a plurality of fasteners  28  to the inside of each flange  62  along the base unit  2  as shown in  FIG. 10  and to the inside of each flange  9  along the support unit  4  as shown in  FIG. 3 . Outer arms  31  are fastened to intermediate unit  3  as represented in  FIG. 10 . Slides  11 B and  11 A separate base unit  2  from intermediate unit  3  and intermediate unit  3  from support unit  4 , respectively, in an offset fashion so as to prevent interference contact during extension and retraction. 
   A variety of linearly extensible slides  11 (A, B) are applicable to the present invention. For example, slides  11 (A, B) may be comprised of two movable linear-shaped and interlocking elements having a low-friction polymer there between. However, preferred embodiments consisted of bearing-based slides  11 (A, B), as described in  FIGS. 11–12 .  FIG. 11  shows one such slide  11 (A, B) having an outer arm  31 , an inner arm  33  with bracket  30  fastened or welded thereon, and a bearing support  32  with a plurality of pair-wise arranged ball bearings  29 . 
   Referring now to  FIG. 12 , the outer arm  31  is a u-shaped channel of linear extent. A bearing support  32 , also of linear extent, is attached in a fixed fashion to the inside of the outer arm  31  and between outer arm  31  and inner arm  33  so as to secure a plurality of ball bearings  29  along the length of the slide  11  (A, B). While it is preferred to have both inner arm  33  and outer arm  31  composed of a metal, the bearing support  32  should be composed of a low-friction polymer, including but not limited to polytetrafluorethylene and polyethylene. Ball bearings  29  were positioned along the bearing support  32  in holes of like-size dimension so as to allow for their rotation within the holes when inner arm  33  traverses the length of the outer arm  31 . A plurality of holes  6  were provided along the length of the outer arm  31  to facilitate attachment with flange  9  along the support unit  4  and with flange  62  along the base unit  2  via fasteners  28 , as shown in  FIG. 10 . A plurality of holes  6  are also provided along the length of the bracket  30  so as to facilitate attachment between slides  11 (A, B) and intermediate unit  3  via fasteners  28  along the planar surface of the intermediate unit  3 , also shown in  FIG. 10 . 
   Referring now to  FIG. 13 , the front of the base unit  2  is shown having a motor  36  at one end and a drive screw  34  along its length. Also shown is a slide  11 B fastened to the inside of each of two flanges  62  disposed along the length of the base unit  2  and perpendicular to the plate  58 . A flange  35  is located adjacent to the lower end. A fourth flange  53  is located along the upper end adjacent to the intermediate unit  3  attached to and perpendicular to the plate  58 , as represented in  FIG. 16 . Flanges  62  are either welded, mechanically fastened or fabricated using metal shaping techniques. Likewise shown is a pair of cables  22 A and  22 B traversing the length of the base unit  2  and parallel about the drive screw  34 . 
   The motor  36  is attached via several fasteners  42  to the flange  35  at the lower end of the base unit  2 , as shown in  FIG. 14 . While various motor  36  types are applicable to the present invention, preferred embodiments were reversible and DC powered. One specific example being a 24V motor, model number 403.979 manufactured by Valeo Auto-Electric Wischer und Motoren GmbH (Motors and Actuators Division) with an office at Stuttgarter Strasse 119 D-74321 Bietigheim, Germany. 
   The motor  36  is directly coupled to the drive screw  34  via a coupler  43  thereby locking the rotational shaft of the motor  36  to the drive screw  34 . The coupler  43  is a metal cylinder having a cavity conforming to the end of both motor shaft and drive screw  34 . A u-shaped bracket  41  is positioned above the motor  36 , adjacent to the coupler  43 , and welded to both plate  58  and flange  35 . The u-shaped bracket  41  has a hole of slightly larger size than the drive screw  34  so as to allow its rotation yet provide lateral support to the drive screw  34 . 
   Referring again to  FIG. 13 , an optional rod  38  is provided parallel to the drive screw  34  along the length of the base unit  2 . The rod  38  passes through a hole in an unobstructed manner along the flange  35  at the lower end of the base unit  2  and the flange  50  at the lower end of the intermediate unit  3 . A lower stop  39  is secured to the rod  38  via a set screw above the flange  35  attached to the base unit  2 . A spring  61  is positioned along the length of the rod  38  between lower stop  39  and flange  35  and depressed by a stop  23  when compound lift  1  is retracted, as shown in  FIG. 14 . An upper stop  40  is likewise secured to the rod  38  via a set screw above the flange  50  along the intermediate unit  3 . Stop  23 , lower stop  39  and upper stop  40  are cylinder shaped elements disposed about the rod  38 . The limit switch  37  is fastened to the flange  35  via at least one nut  45 , also shown in  FIG. 14 . The rod  38  is mechanically attached to the optional limit switch  37  below the flange  35 , as shown in  FIGS. 13–14 . 
   While limit switches  37  are understood within the art, preferred embodiments of the present invention included a mechanically activated two position electrical device The limit switch  37  is electrically connected to the motor  36  through a controller  106  or directly via a wire  66  shown in  FIG. 1 . 
   Interaction between flange  50  and lower stop  39  or upper stop  40  communicates the location of the intermediate unit  3  along its travel length to the limit switch  37 . For example, contact between lower stop  39  and flange  50  during retraction moves the rod  38  in a downward direction so as to mechanically trip the limit switch  37  thereby terminating power to the motor  36  and reversing the rotation of motor  36  and drive screw  34  attached thereto. Likewise, contact between upper stop  40  and flange  50  during extension moves the rod  38  in an upward direction so as to mechanically trip the limit switch  37  thereby terminating power to motor  36  and again reversing the rotation of motor  36  and drive screw  34 . 
   Flanges  47 ,  50  are located at either end of the planar dispose plate  52  comprising the intermediate unit  3  and may be located to the same side or opposite sides of the plate  52 . Plate  52  may be composed of a metal and the flanges  47 ,  50  formed via conventional metal forming techniques. Referring now to  FIG. 15 , a stiffener  51 , typically a hollow beam or u-shaped element, is mechanically fastened to the plate  52  in a lengthwise fashion so as to resist deflection of the intermediate unit  3  during extension and retraction. 
   Referring again to  FIG. 15 , the drive screw  34  is shown passing through a first bushing  48  mechanically secured to the flange  50  via a pair of fasteners  49 . Flange  50  also supports a pair of pulleys  46 B oriented in a downward fashion, also mechanically fastened thereto. The upper end of the intermediate unit  3  has a pair of pulleys  46 A oriented in an upward direction attached to a flange  47  of identical design and arrangement as in flange  50 , as shown in  FIG. 17 . Pulleys  46 (A, B) are angled in an inward direction to minimize their protrusion beyond the flanges  47 ,  50 , yet allowing sufficient distance between cables  22 (A, B) and flanges  47 ,  50  to avoid their contact. Pulleys  46 (A, B) and their fastening are understood in the art. 
   Referring now to  FIG. 16 , the end of the drive screw  34  is mechanically secured to the flange  53  at the upper end of the base unit  2  via a second bushing  54 . It is preferred that the drive screw  34  not have threads along its length contacting the second bushing  54 . The second bushing  54  is composed of a low-friction material, preferably a polymer, allowing the drive screw  34  to freely rotate in a secured fashion. The second bushing  54  is held in place via an interference fit between second bushing  54  and hole through flange  53 . 
   Referring again to  FIG. 16 , rotation of the drive screw  34  is communicated to the intermediate unit  3  via the first bushing  48 . First bushing  48  is secured to the flange  50  at the bottom of the intermediate unit  3  between a pair of pulleys  46 B. A flat  57  is located along one edge of the first bushing  48  so as to contact the plate  52  and prevent rotation of the first bushing  48  when drive screw  34  rotates. Unlike the second bushing  54  described above, the first bushing  48  is preferred to be composed of a low-friction metal, one example being brass, having a thread pattern of likewise design to engage the thread pattern along the drive screw  34 . Rotation of the drive screw  34  is transferred to the first bushing  48  so as to move the intermediate unit  3  attached thereto in a linear fashion along the length of the drive screw  34 . 
   While movement of the intermediate unit  3  is via the drive screw  34 , movement of the support unit  4  is via cables  22 (A, B). Referring now to  FIG. 18  shows a schematic diagram describing the arrangement of a cable  22 A about one side of the drive screw  34 . One end of the cable  22 A is fastened to the flange  35  at the lower end of the base unit  2  and vertically aligned upward so to contact a pulley  46 A fastened to the flange  47  at the upper end of the intermediate unit  3 . Thereafter, the cable  22 A is vertically aligned downward so to contact a pulley  46 B fastened to the flange  50  at the lower end of the intermediate unit  3 . The path of the cable  22 A effectively encircles the intermediate unit  3  and contact is effected via a pair of pulleys  46 (A, B) along one side of the drive screw  34 , as graphically represented in  FIG. 18 . Thereafter, the end of the cable  22 A is fastened to a second flange  53  at the upper end of the base unit  2 . The cable  22 A is fixed to the rear of the support unit  4  via a cable fastener  24 , as described above. The described arrangement is required along both sides of the drive screw  34  to effect coupled movement between intermediate unit  3  and support unit  4 . 
   Referring now to  FIG. 19 , the first cable end  63  is terminated by a t-shaped connector  59  crimped, mechanically fastened or welded to the cable  22 A. The t-shaped connector  59  either resides within a hole or slot along the flange  35  at the lower end of the base unit  2  thereby securing it to the compound lift  1 , as shown in  FIG. 14 . 
   Referring now to  FIG. 20 , the second cable end  64  is terminated by a threaded connector  55  also crimped, mechanically fastened or welded to the cable  22 A. The threaded connector  55  partially traverses a hole within the flange  53  at the upper end of the base unit  2 . A nut  60  is threaded onto the threaded connector  55  and tighten so as to remove slack along the length of the cable  22 A. 
   Referring now to  FIG. 21 , a block diagram describes the control function of the motor  36  and hence extension and retraction of both intermediate unit  3  and support unit  4 . A controller  106  is electrically connected between a transformer  100  and a motor  36 , all such devices being understood in the art. The transform  100  receives AC power via a power cord thereafter converting it to DC before communicating it to the motor  36 . 
   STOP, START, and REVERSE, are communicated to the controller  106  via one or more means. For example, a remote control transmitter  104  may communicate wireless commands to a remote control receiver  103  electrically connected to the controller  106 . It is likewise possible to communicate commands via a switch  105 , one example being the limit switch  37  as described above, or other manual control  107 , one example being a toggle switch, electrically connected to the controller  106 . Furthermore, it is possible to employ a rotary motion sensor  108  which counts the number of rotations and rotational direction of the drive screw  34  so as to map the rotational history of the drive screw  34 . The components for such arrangements are understood in the art. 
   The controller  106  may also control power flow to one more sockets. For example, a television socket  102  may be electrically connected to the controller  106  so that power is automatically communicated to a low-profile display  70  when the compound lift  1  is fully extended and terminate power when retracting. Likewise, it is possible to have an socket  101  electrically connected to the controller  106  so as to provide power to a VCR or DVD when the compound lift  1  is extended or terminate power when retracting. 
   The description above indicates that a great degree of flexibility is offered in terms of the present invention. Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.