Patent Abstract:
An exemplary adjustable stand ( 20 ) for displays includes a main support ( 22 ), a movable rack ( 25 ), an adjusting system ( 26 ) and a balance mechanism ( 28 ). The movable rack is slidably mounted on the main support. The adjusting system includes at least one pinion gear ( 266 ) rotatably attached on the movable rack and at least one rack gear ( 267 ) fixed to the main support. The at least one pinion gear meshes with the at least one rack gear. The balance mechanism is mounted between the main support and the movable rack for balancing gravity of the movable rack and components fixed relative to the movable rack. The present invention further discloses a stand ( 10 ) including a support bracket ( 30 ), a base ( 40 ) and the adjustable stand for connecting the support and the base.

Full Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to adjustable stands for display devices, more particularly to an adjustable stand for height-adjustable supporting a display device. 
   2. Discussion of the Related Art 
   Presently, flat-panel display devices such as liquid crystal display (LCD) devices are widely used due to excellent display quality and their thin bodies. Typically, a function of adjusting an altitude of the flat display device can be realized via a support stand having an adjustable stand. 
   Referring to  FIG. 4 , a typical adjustable stand for adjusting an altitude of a flat-panel display device includes a support member  5 , an elevating member  6 , a coil spring  7 , a shaft  71 , and four fastening members  73  and  76 . The support member  5  includes a base plate  50  and two side plates  51  perpendicularly extended from opposite sides of the base plate  50 . A flange  53  is formed around an end of each side plate  51  opposite to the base plate  50 . The base plate  50 , the side plates  51 , and the flanges  53  cooperatively define a receiving groove  54 . Two guide rails  55  are formed on the inner surfaces of two side plates  51  correspondingly. Each of the flanges  53  defines a fixing hole  531  adjacent to an end. The elevating member  6  has a connecting portion  61  for connecting the LCD panel on a top side, and defines two positioning holes  62  at a bottom side. The elevating member  6  forms two sliding portions  63  for engaging with the guide rails  55 . The shaft  71  defines two through holes  711  in opposite ends. An end of the spring  7  is sleeved on the shaft  71 , and another end of the spring  7  defines two through holes  75 . 
   In assembling of the stand  100 , the elevating member  6  is inserted into the support member  5 , with the sliding portions  63  of the adjustable stand  6  engaging in the guide rails  55  of the support member  5 . Each fastening member  33  extends through one corresponding through hole  711  of the shaft  71  and one corresponding fixing hole  531  of the flanges  53 , thus fixing the shaft  71  to the support member  5 . Each fastening member  73  extends through one corresponding through hole  75  of the spring  7  and one corresponding positioning hole  62  of the elevating member  6 , thus fixing the spring  7  to the elevating member  5 . In use, the elevating member  6  can be driven to slide relative to the support member  5  by an external force. When the external force is released, the liquid crystal display panel connected to the elevating member  6  can be remained in a predetermined position, due to a balance of a weight of the liquid crystal display panel and the elevating member  6 , an elastic force of the spring  7 , and a friction force between the elevating member  6  and the support member  5 . 
   However, a friction force between the elevating member  6  and the support member  5  is great since the contacting area of them is large, thus a user may need to exert great effort to push the elevating member  6  to slide relative to the support member  5 . 
   Therefore, an adjustable stand for display devices to solve the aforementioned problems is desired. 
   SUMMARY 
   An exemplary adjustable stand for displays includes a main support, a movable rack, an adjusting system and a balance mechanism. The movable rack is slidably mounted on the main support. The adjusting system includes at least one pinion gear rotatably attached on the movable rack and at least one rack gear fixed to the main support. The at least one pinion gear meshes with the at least one rack gear. The balance mechanism is mounted between the main support and the movable rack for balancing gravity of the movable rack and components fixed relative to the movable rack. 
   Other advantages and novel features will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the adjustable stand for flat display devices. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
       FIG. 1  is an assembled, isometric view of a stand for display device employed in a flat-panel display device in accordance with a preferred embodiment of the present invention. 
       FIG. 2  is a partially assembled, isometric view of an adjustable stand for flat-panel display device of  FIG. 1 . 
       FIG. 3  is an exploded, isometric view of the adjustable stand for flat-panel display device of  FIG. 2 . 
       FIG. 4  is an exploded, isometric view of a conventional adjustable stand. 
   

   DETAILED DESCRIPTION OF THE EMBODIMENTS 
   A stand according to an exemplary embodiment is adapted for use in a flat-panel display device such as a liquid crystal display device. Referring to  FIG. 1 , a support stand  10  includes an adjustable stand  20 , a support bracket  30  for mounting a liquid crystal display panel (not shown), and a base  40  for supporting the adjustable stand  20 . The adjustable stand  20  is adjustably connected to the support bracket  30  and the base  40 . 
   Referring to  FIG. 2 , the adjustable stand  20  includes an upper support  21 , a main support  22 , a movable rack  25 , an adjusting system  26 , and a balance mechanism  28 . 
   Referring to  FIG. 3 , the upper support  21  includes a flat sheet  212  and two side sheets  214  formed perpendicularly at opposite sides of the flat sheet  212  correspondingly. The flat sheet  212  defines two connecting holes  216  in a middle portion. 
   The main support  22  includes a main portion  222  and two sidewalls  223  perpendicularly extending from opposite sides of the main portion  222  correspondingly. Two mounting holes  228  are defined in the sidewalls  223  correspondingly and the mounting holes  228  are aligned in a same line across the main portion  222 . Two connecting holes  229  are defined in the main portion  222  of the main support  22  corresponding to the connecting holes  216 . When assembled, the upper support  21  is fixed to an end of the main support  22  by a plurality of pivot shafts (not shown). 
   The movable rack  25  defines two latching holes  252  adjacent one end, four engaging holes  256 , and a mounting hole  258 . Four connecting members  254  are configured on the movable rack  25  for connecting the movable rack  25  to the support bracket  30 . 
   The adjusting system  26  includes two gear sets (not labeled). For exemplary purpose, only one of the gear sets is detailed. The gear set includes two pivot shafts  262 , two washers  264 , two pinion gears  266 , a rack gear  267 , two bearings  268 , and two nuts  269 . In the exemplary embodiment, two bolts partially threaded at the free end are used as the pivot shafts  262  and connected to movable rack  25  with the nuts  269 . When assembled, the pivot shafts  262  are extended through the washers  264 , the pinion gears  266  the bearings  268 , two engaging holes  256  of the movable rack  25 , and the nuts  269  correspondingly, thereby rotatably mounting the pinion gears  266  to the movable rack  25 . The rack gear  267  is configured for fixing to the main support  22  and meshing with the pinion gears  266 . 
   The balance mechanism  28  includes two pulley systems  23 , a cable  242 , a fixing module  29 , and a resisting device  27 . 
   For exemplary purpose, only one of the pulley systems  23  is detailed. The pulley system  23  includes a pivot shaft  232 , a first washer  233 , a wheel  234 , a bearing  235 , a second washer  237 , and a nut  238 . The pivot shaft  232  has a first end  2324  and a second end  2336  opposite to the first end  2324 . The wheel  234  has a main body  2342  and two flanges  2344  formed at opposite ends of the main body  2342  correspondingly, thus forming a groove (not labeled) around a circumference of the wheel  234 . When assembled, the first end  2324  of the pivot shaft  232  is inserted through the first washer  233 , the wheel  234 , the bearing  235 , the second washer  237 , and engaged with the nut  238 , in that order, thereby forming the pulley system  23 . The fixing module  29  includes a coil spring  292 , two washers  295 , a bearing  296 , and a shaft  297 . The coil spring  292  is schematically shown in figures. When assembled, the bearing  296  is received in the coil spring  292  and sleeved on the shaft  297 . Ends of the shaft  297  is fixedly supported in the mounting holes  228  of the main support  22  correspondingly, and also protrudes through the bearing  296  that is fastened to an inner end of the coil spring  292  and the washers  295 , in that order, thereby fixing the inner end of the coil spring  292  to the main support  22 . An outer end of the coil spring  292  defines two through holes  293 . The balance mechanism  28  further includes two fastening members  244 . When assembled, the cable  242  is latched to one of the latching hole  252  of the movable rack  25 , looped around the wheel  234  of one of the pulley systems  23 , looped through the through holes  293  of the coil spring  292  correspondingly, looped around another one of the pulley systems  23  and latched to another of the latching hole  252  correspondingly. The fastening members  244  correspondingly secured to the ends of the cable  242 , thus preventing the ends of the cable  242  from slipping and/or sliding out of the latching holes  252 . 
   The resisting device  27  includes a friction member  272 , a spacer  274  and a supporting member  276 . The supporting member  276  extends out of the movable rack  25 . The friction member  272  is configured at the free end of the supporting member  276  after the spacer  274  is sleeved on the supporting member  276 . In other words, the spacer  274  is sandwiched between the movable rack  25  and the friction member  272 . The friction member  272  contacts with the main support  22 , thus creating a friction force between the movable rack  25  and the main support  22 . The friction member  272  and the spacer  274  are made of rubber. 
   When assembled, the pulley systems  23  are assembled as detailed above. The first ends  2324  of the pivot shafts  232  are fastened in the connecting holes  216  of the upper support  21 . The pinion gears  266  are fastened to the movable rack  25  as detailed above. The resisting device  27  is mounted to the movable rack  25  as detailed above. The cable  242  is assembled to the movable rack  25 , the pulley systems  23  and the coil spring  292  of the fixing module  29  as detailed above. The rack gears  267  are fastened along the two sides of the main support  22  respectively. Then the upper support  21  and the movable rack  25  are coupled to the main support  22 , with the side sheets  214  of the upper support  21  and the resisting device  27  mounted to the movable rack  25  facing the main support  22 . The upper support  21  is fixed to the main support  22 . The second ends  2326  of the pivot shafts  232  engages in the connecting holes  229  of the main support  22 . The rack gears  267  engage with the pinion gears  266  correspondingly. The shaft  297  is extended through the main support  22 , the bearing  296 , and the washers  295 , thereby fixing the inner end of the coil spring  292  to the main support  22 . Thus, the adjustable stand  20  is assembled. The support bracket  30  is fixed to the movable rack  25 , and the base  40  is fixed to a bottom end of the main support  22 , thus the stand  10  is assembled. The support bracket  30  is connected to a flat-panel display of flat-panel display device. 
   The movable rack  25  can adjustably slide relative to the main support  22  via the engagement of the rack gears  267  and the pinion gears  266 . As such, a height of the liquid crystal display panel of the display device relative to the base  40  can be adjustably raised or lowered. A coil force provided by the coil spring  292  of the fixing module can counter balance a weight of the movable rack  25  and the support bracket  30  attached with the panel. Furthermore, a friction force is generated between the resisting device  27  and the main support  22 . The friction force keeps/maintains the movable rack  25  in a predetermined position. 
   When the altitude of the display needs to be adjusted, an external force is applied on the display to force the movable rack  25  sliding relative to the main support  22 . The external force is released when the display reaches a predetermined altitude. The movable rack  25  together with the display maintains in the predetermined position because a composition force of the elastic force of the coil spring  292 , the friction force between the resisting device  27  and the main support  22  equals to the total gravitational force of the movable rack  25 , the support bracket  30  and the display. 
   The pulley systems  23  and the adjusting system  26  are made of plastic. Therefore, the lift mechanism  20  is light and has low manufacturing cost. The gear sets may be only one or more than two. Each gear set may have only one pinion gear  266  or more than two pinion gears  266 . The upper support  21  may be omitted. Correspondingly, the pulley systems  23  are mounted on the main support  22  directly. 
   It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.

Technology Classification (CPC): 5