Abstract:
A motorized lift for an electronic display includes a reversible electric motor operably coupled to a first shiftable column and a second shiftable column, the coupling to the first column being direct and the coupling to the second column being indirect whereby operation of the electric motor in a first rotational direction acts to simultaneously extend the first and second columns and operation of the electric motor in a second and opposite rotational direction acts to simultaneously retract the first and second columns. A method of operating a motorized lift for an electronic display is further included.

Description:
RELATED APPLICATION  
       [0001]     The present application claims the benefit of U.S. Provisional Application Ser. No. 60/756,069, filed Jan. 4, 2006 and incorporated herein in its entirety by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention relates to electronic display devices and in particular motorized lifting devices for electronic display devices.  
       BACKGROUND OF THE INVENTION  
       [0003]     Flat panel electronic display devices are becoming increasingly popular for home use as production increases and prices come down. Especially popular are large flat panel display devices, typically plasma screens, which have enabled a large screen size to be presented in a device of relatively compact volume.  
         [0004]     While being generally lighter than CRT devices, flat panel displays in large screen sizes are still relatively heavy for an individual to manage. As a consequence, it is desirable to mount large flat panel display devices on a mounting device that enables an individual to position the device for viewing.  
         [0005]     Motorized mounts are particularly desirable since they require the least amount of physical effort for positioning. Prior motorized mounts, particularly vertical lifting devices, however, have generally not been entirely satisfactory in that the motion of the device is typically uneven and somewhat jerky.  
         [0006]     What is needed in the industry is a motorized vertical lift for a flat panel display that offers smooth operation.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention addresses the aforementioned need in the industry by providing a smooth operating motorized vertical lifting device for a flat panel electronic display. The vertical lifting device incorporates a single drive motor, actuation of the drive motor acting to simultaneously, cooperatively extend two concentric extension columns. In the retracted disposition, the two columns are substantially withdrawn into a casing. When extended, the two columns extend above the casing, a first column extending above the upper margin of a second column. Preferably, the first column extends above the second column a distance that is generally equal to a distance that the second column extends above the casing. The two columns may be positioned at any position intermediate the fully retracted and the fully extended positions so that the height of the flat panel display may set at any desired disposition for viewing.  
         [0008]     In an embodiment, the drive motor directly drives a jacking screw drive system operably coupled to the second column and indirectly drives a cable and pulley system that operably couples the first and second columns. Such a drive mechanism smoothly extends and retracts the motorized display of the present invention.  
         [0009]     An embodiment of the present invention includes a motorized lift for an electronic display, including a reversible electric motor operably coupled to a first shiftable column and a second shiftable column, the coupling to the first column being direct and the coupling to the second column being indirect whereby operation of the electric motor in a first rotational direction acts to simultaneously extend the first and second columns and operation of the electric motor in a second and opposite rotational direction acts to simultaneously retract the first and second columns. An embodiment of the present invention further include a method of operating a motorized lift for an electronic display. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective view of a motorized vertical lift for a flat panel electronic display according to an embodiment of the invention;  
         [0011]      FIG. 2  is a side elevation view of the lift depicted in  FIG. 1  in a fully extended position and with a flat panel display attached;  
         [0012]      FIG. 3  is a front elevation view of the list depicted in  FIG. 1 ;  
         [0013]      FIG. 4  is a perspective view of the lift of  FIG. 1  with the casing removed;  
         [0014]      FIG. 5  is a front elevation view of the lift of  FIG. 1  with the casing and lower extension column removed to expose the drive mechanism of the device;  
         [0015]      FIG. 6  is a fragmentary perspective view of a portion of the drive mechanism of a lift according to an embodiment of the invention;  
         [0016]      FIG. 7  is a fragmentary bottom perspective view of a portion of the drive mechanism of a lift according to an embodiment of the invention;  
         [0017]      FIG. 8  is fragmentary top perspective view of another portion of the drive mechanism of a lift according to an embodiment of the invention; and  
         [0018]      FIG. 9  is a perspective view of the lift of  FIG. 1  with the casing and lower extension column removed to expose the drive mechanism of the device.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]     Motorized lift of the present invention is depicted generally at  10  in the figures. The motorized display lift  10  generally includes the following major components: base  12 , housing  14 , lower extension column  16 , upper extension column  18 , display mounting bracket  20 , and drive mechanism  22 .  
         [0020]     Base  12  of the motorized lift  10 , as depicted in  FIGS. 1 and 4 , includes a pair of spaced apart, parallel mount plates  150 . A plurality of mount bores are defined in the mount plates for fasteners that can fixedly mount the motorized display lift  10  to an underlying surface, such as the surface of a cabinet. A pair of spaced apart end plates  154  are fixedly coupled to the respective mount plates  150 . An aperture  156  may be defined in the respective end plates  154 . A pair of spaced apart, parallel vertical support plates  158  are fixedly coupled to the mount plates  150  and the end plates  154 . A horizontal support plate  160  is fixedly coupled to the upper margins of the respective vertical support plates  158  and the end plates  154 . An interior space is defined beneath the horizontal support plate  160  in which drive components can be mounted as detailed below. A plurality of apertures are defined in the horizontal support plate  160  for accommodating such mounting.  
         [0021]     The second component of the motorized lift  10  is the housing  14 , as depicted in  FIG. 1 . Housing  14  generally includes bottom plate  24 , top plate  26 , and casing  28 , fastened together with fasteners  30 . The bottom plate  24  and top plate  26  each have suitable apertures defied therein for accommodating the passage of mechanical components therethrough. The inner margin of the casing  28  is preferably formed of a smooth finish in order to minimize the buildup of friction forces with the passage of bearings along the surface of the inner margin, as detailed below.  
         [0022]     The third component of the motorized lift  10  is the drive mechanism  22 , as depicted in  FIGS. 4-7  and  9 . Drive mechanism  22  generally includes the following subcomponents: drive train assembly  32 , lower platform  34 , upper platform  36 , cable and pulley rigging  38 , and display cable management assembly  40 .  
         [0023]     Drive train assembly  32  of the drive mechanism  22  generally includes motor  42 , drive sheave  44 , drive belt  46 , sheave  48 , jacking screw  50 , and nut  52 . Motor  42  is mounted on bottom plate  24  with output shaft  54  depending therefrom and extending through an aperture defined in the bottom plate  24  and a corresponding aperture defined in the horizontal support plate  160  of the base  12 . Drive sheave  44  is received on output shaft  54  and is driveably coupled to driven sheave  48  through drive belt  46 . Tensioner  56  having a positionally adjustable pulley  57  the bears on the outer margin of the drive belt  46  may be provided to maintain proper tension and alleviate slack in drive belt  46 .  
         [0024]     Jacking screw  50  (see particularly  FIGS. 5-7 ) extends through an aperture defined in the bottom plate  24  and a corresponding aperture defined in the horizontal support plate  160  of the base  12 . Bearing  58 , mounted in bottom plate  24 , rotatably supports the jacking screw  50 . End portion  60  of the jacking screw  50  projects below the horizontal support plate  160  and receives sheave  48  thereon. End portion  60  of jacking screw  50  has threaded portion  62  which receives nut  64  to fixedly retain sheave  48  on jacking screw  50 .  
         [0025]     Referring to  FIG. 6 , jacking screw  50  has spiral thread  66  which engages interior threads provided in jacking nut  52  so that jacking nut  52  is threaded on screw  50 . Nut  52  is fixed to lower platform  34  with bolts  68 . Slide bearings  70 ,  72 , are attached on each side of lower platform  34  with bolts  74 , and positioned so that outer surface  76  is slidably in contact with the inner margin of casing  28 . Jacking nut  52  is rotationally constrained by the contact of the slide bearings  70 ,  72 , with the inner margin of casing  28 . In this manner, the jacking nut  52  is selectively caused to move upward or downward with the respective clockwise or counterclockwise rotation of the jacking screw  50 . Advantageously, slide bearings  70 ,  72 , may be made from a low friction material such as Delrin®.  
         [0026]     As depicted in  FIG. 4 , lower extension column  16  is generally cylindrical. In the depicted retracted disposition, lower extension column  16  is positioned with lower end  78  resting on lower platform  34  and the lower end portion of outer surface  80  contacting the curved inner surface  82  of slide bearings  70 ,  72 . Jacking screw  50  is received generally coaxially through hollow interior  84  of lower extension column  16 . Upper end  86  of lower extension column  16  projects upward through aperture  88  defined in top plate  26 .  
         [0027]     Upper platform  36  (see  FIGS. 6 and 7 ) is generally cylindrical in shape and defines aperture  90 , through which jacking screw  50  is generally coaxially received. Jacking screw passes through the aperture  90  without threadedly engaging the upper platform  36 . Lower end  92  of upper extension column  18  is received between slide bearings  94 ,  96 , and rests on upper platform  36  when upper extension column  18  is in the retracted disposition. Slide bearings  94 ,  96 , which again may be made from a low friction material such as Delrin®, are positioned so as to be in contact with inner surface  98  of lower extension column  16 . Like lower extension column  16 , upper extension column  18  is also hollow so that screw  50  in received therein.  
         [0028]     Rigging  38  (see  FIGS. 5-7 , and  9 ) is the fourth component of the motorized lift  10  and generally includes cable  100 , upper pulley  102 , and lower pulley  104 . Cable  100  is one continuous cable, but for clarity is described in three portions  100   a,    100   b,  and  100   c.  These three portions of cable  100  are depicted best in  FIG. 5 . Cable  100   a  is fixed at a first end  105  to bottom plate  24  at aperture  106 . From aperture  106 , cable  100   a  extends upwardly through aperture  108  in lower platform  34  without engaging lower platform  34  and thence through slot  110  in slide bearing  94 , again without engaging slide bearing  94 . From there, cable  100   a  extends to upper pulley  102 . Upper pulley  102  is rotatably attached to interior surface of lower extension column  16  proximate the upper margin of lower extension column  16 . Cable  100   a  is reeved around upper pulley  102 . From thence, cable  100   b  extends downwardly to pin  114 . From pin  114 , cable  100   b  extends further downward to lower pulley  104  and is reeved around lower pulley  104 . The two portions  100   a ,  100   b  of cable  100  so far described are generally parallel to one another, the first portion ascending to upper pulley  102  and the second descending to lower pulley  104 . Lower pulley  104  is rotatably attached to lower platform  34 , lower platform  34  being affixed to lower column  16 . Accordingly, both of the pulleys  102 ,  104  are coupled to lower column  16 . See  FIG. 7 . After passing around lower pulley  104 , cable  100   c  extends upward and the second end  107  of cable  100  is fixed to top plate  26 . Cable portion  100   c  is likewise generally parallel to cable portions  100   a  and  100   b.  Neither top plate  26  nor bottom plate  24  is moveable during extension or retraction of the two columns  16 ,  18 . In distinction, both pulleys  102 ,  104  translate upward and downward during respective extension and retraction of the two columns  16 ,  18 .  
         [0029]     Significantly, it is at pin  114  that cable  100  is fixedly coupled to upper extension column  18 . Such coupling makes the length of cable  100  between pin  114  and first end  105  fixed in length and makes the length of cable  100  between pin  114  and second end  107  fixed in length. With upward motion of the lower extension column  16 , the length of cable  100  between pin  114  and first end  105  acts to positively pull upper extension column  18  upward, thereby extending upper extension column  18 . Conversely, with downward motion of the lower extension column  16 , the length of cable  100  between pin  114  and second end  107  acts to positively pull upper extension column  18  downward, thereby retracting upper extension column  18 . By fixing the two lengths of cable  100  at pin  114 , upper extension column  18  can be positively extended, positively retracted and positively held in any position between full retraction and full extension as a function of the position of the lower extension column  16 . As noted above, the lower extension column  16  is directly shiftably coupled to the motor  42  of the drive mechanism  22 . Since upper extension column  18  is coupled to lower extension column  16 , upper extension column  18  is indirectly shiftably coupled to the motor  42  of the drive mechanism  22 . Actuation of motor  42  of the drive mechanism  22  therefore acts to simultaneously translatably shift both the lower extension column  16  and the upper extension column  18 .  
         [0030]     In extending operation, with the motorized lift  10  in the fully retracted position depicted in  FIGS. 1 and 9 , motor  42  rotates drive sheave  44 , in turn rotating driven sheave  48  and jacking screw  50  by means of drive belt  46 . As jacking screw  50  rotates, jacking nut  52  is constrained from rotating by sliding contact with the inner margin of the casing  28 . Accordingly, jacking screw  50  is threaded upwardly along screw  50 , causing lower platform  34  to move upwardly relative to bottom plate  24  and thereby extending lower extension column  16  upwardly through aperture  88  in top plate  26 . As lower extension column  16  moves upward elevating the pulley  102  of the rigging  38 , rigging  38  causes upper extension column  18  to be pulled upward relative to the lower extension column  16  and simultaneously extends from upper end  86  of lower extension column  16  until the motorized lift  10  reaches the fully extended position depicted in  FIG. 2 . Preferably, rigging  38  is arranged so that the rate of extension of lower extension column  16  from top plate  26  and the rate of extension of upper extension column  18  from lower extension column  16  are approximately equal, lending the mechanism a smooth operating appearance. Coordinating the rates of extension of the columns  16 ,  18  is effected by the relative diametric sizing of the two pulleys  102 ,  104 . In a preferred embodiment, the diameter of pulley  102  is generally twice that of pulley  104 .  
         [0031]     When the rotation of motor  42  is reversed, the mechanism operates in a similar fashion to retract lower extension column  16  and upper extension column  18  within housing  28 . As lower extension column  16  moves downward lowering the pulley  104  of the rigging  38 , rigging  38  causes upper extension column  18  to be pulled downward relative to the lower extension column  16 . An electronic display device  116  attached to upper extension column  18  with display mounting bracket  20  may thus be vertically raised and lowered with the motorized display lift  10 .  
         [0032]     Motor  42  may be turned on and off at the travel limits of the mechanism with limit switches  118  mounted on threaded rod  120 . The position of limit switches  118  may be adjusted from outside the device by turning end  122  of threaded rod  120 , which projects through top plate  26 . Alternatively, a manual switch may be electrically communicatively coupled to the motor  42  and the columns  16 ,  18  mat be manually stopped at any desired disposition between the fully extended and fully retracted dispositions.  
         [0033]     Cable management assembly  40  generally includes pulley  124  which is rotatably mounted to lower platform  34  with bracket  126 . Cables, such as power and video signal cables for the flat panel display may be routed through aperture  128  in bottom plate  24  and upward through casing  28  where they are clipped to top plate  26 . The cables then extend downwardly to loop around pulley  124  before extending upwardly again through aperture  130  in top plate  26 . As the lift is operated, pulley  124  takes up any slack in the cables, thereby preventing binding and tangling of cables inside casing  28 .