Abstract:
An adjustable support device includes a support, a lift mechanism, and a pulley unit. The support includes at least two casings which are slidably connected with each other so as to adjust the length of the support. The lift mechanism includes a threaded rod screwed into a nut for changing the distance between the casings. The pulley unit is adapted for driving the casings. The present invention provides a labor-saving effect for operation.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an adjustable support device, and more particularly to a support in conjunction with a lift mechanism and a pulley unit to move at least two casings of the support with each other. 
         [0003]    2. Description of the Prior Art 
         [0004]    Taiwanese Patent No. M284511 discloses a furniture elevator structure, which comprises a screw and a nut for rising and descending. It is necessary to use a longer screw for adjusting a higher position of the elevator. The adjusting speed is subject to the threads of the screw. When the density of the threads is high, the adjusting speed will be slow. But, it is able to support a heavier object. When the density of the threads is low, the adjusting speed will be fast. But, the supporting force of the screw and the nut is low. It is unable to support a heavier object. In addition, the longer screw needs more working procedures. This is not easy to lower the cost. The user takes more time and needs more strength to adjust the length with the longer screw. 
         [0005]    Accordingly, it is necessary to improve the shortcomings of this furniture elevator structure. 
       SUMMARY OF THE INVENTION 
       [0006]    In view of the aforesaid shortcomings, the inventor of the present invention has devoted himself based on his many years of practical experiences to the development of an adjustable support device. 
         [0007]    The present invention comprises a support, a lift mechanism, and a pulley unit. The support includes at least two casings. The lift mechanism is turned to drive the pulley unit and to move the casings for adjusting the length of the support. 
         [0008]    A first objective of the present invention is that the support comprises at least two casings depending on the demand of the user. The support may comprise more casings which are moved with each other for adjusting the length of the support as desired. 
         [0009]    A second objective of the present invention is that a threaded rod is risen or descended for moving the casings. With a pulley, the support is adjusted synchronously for its length. This is labor-saving for the user to adjust the length of the support. 
         [0010]    A third objective of the present invention is that the threaded rod is screwed to a nut. The threaded rod and the nut provide a supporting force to bear the weight of the support, preventing the threaded rod from sliding down. The casings are limited to slide by themselves. 
         [0011]    A fourth objective of the present invention is that a gear unit may be connected with a driving device for driving the support to rise or to descend. The driving device may be a handle or an electric motor. 
         [0012]    A fifth objective of the present invention is that a driving gear may be connected with a linking rod to connect with a plurality of supports. A driven gear is connected with the driving device for rising or descending the plurality of supports. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a cross-section view according to a first preferred embodiment of the present invention; 
           [0014]      FIG. 2  is another cross-section view according to the first preferred embodiment of the present invention; 
           [0015]      FIG. 3  is a cross-section view according to a second preferred embodiment of the present invention; 
           [0016]      FIG. 4  is a perspective view according to the second preferred embodiment of the present invention connected with a handle; 
           [0017]      FIG. 5  is a perspective view according to the second preferred embodiment of the present invention connected with an electric motor; 
           [0018]      FIG. 6  is a cross-section view showing another type of a lift mechanism according to the first preferred embodiment of the present invention; 
           [0019]      FIG. 7  is a cross-section view showing another type of a lift mechanism according to the second preferred embodiment of the present invention; 
           [0020]      FIG. 8  is a perspective view according to a third preferred embodiment of the present invention connected with a handle; and 
           [0021]      FIG. 9  is a perspective view according to the third preferred embodiment of the present invention connected with an electric motor. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings. 
         [0023]    As shown in  FIGS. 1 and 2 , an adjustable support device according to a first preferred embodiment of the present invention comprises a support  1 , a lift mechanism  2 , and at least a pulley unit  3 . The support  1  comprises a first casing  10  and a second casing  11  which are slidably connected to each other. The lift mechanism  2  is disposed in the first casing  10  and the second casing  11 . The pulley unit  3  is also disposed in the first casing  10  and the second casing  11 . The pulley unit  3  comprises at least a first pulley  30  and a first transmission belt  301 . The first pulley  30  is connected to the lift mechanism  2 . The first transmission belt  301  has a first end connected to the first casing  10  and a second end inserted through the first pulley  30  and connected to the second cashing  11 . The lift mechanism  2  comprises a gear unit  20 , a threaded rod  21 , a sleeve  22 , a nut  23 , and a carrying base  24 . The gear unit  20  is disposed at an upper end of the first casing  10 . An upper end of the threaded rod  21  is connected to the gear unit  20 . The nut  23  is disposed at an upper end of the sleeve  22 . A lower end of the threaded rod  21  is inserted through the nut  23  and screwed into the sleeve  22 . The sleeve  22  is connected with the first pulley  30 . The carrying base  24  is disposed at a lower end of the sleeve  22  and connected with the second casing  11 . When the gear unit  20  is turned by a user, the threaded rod  21  will be driven to rotate and move with respect to the sleeve  22 . The first casing  10  is linked to move with respect to the second casing  11 . With the transmission belt  301  and the first pulley  30 , the lift mechanism  2  is operated with ease. 
         [0024]    As shown in  FIG. 3 , at least a third casing  12  is provided between the first casing  10  and the second casing  11 . The first casing  10 , the second casing  11 , and the third casing  12  are slidably connected to each other. The gear unit  20  is disposed at the upper end of the first casing  10 . The upper end of the threaded rod  21  is connected to the gear unit  20 . The nut  23  is disposed at the upper end of the sleeve  22 . The lower end of the threaded rod  21  is inserted through the nut  23  and screwed into the sleeve  22 . The sleeve  22  is connected with the first pulley  30 . The carrying base  24  is disposed at the lower end of the sleeve  22  and connected with the third casing  12 . One end of the first transmission belt  301  is connected to the first cashing  10 , and the other end of the first transmission belt  301  is inserted through the first pulley  30  and connected to the second cashing  11 . The pulley unit  3  further comprises at least a second pulley  31 , at least a second transmission belt  311 , at least a third pulley  32 , and at least a third transmission belt  321 . The second pulley  31  and the third pulley  32  are disposed at lower ends of two sides of the third casing  12 , respectively. The second transmission belt  311  and the third transmission belt  321  are connected to lower ends of two sides of the first casing  10 , inserted through the second pulley  31  and the third pulley  32 , and then connected to upper ends of two sides of the second casing  11 . When the gear unit  20  is turned, the threaded rod  21  will be driven to rotate and move with respect to the sleeve  22 . The first casing  10  is linked to move with respect to the third casing  12 , with the second transmission belt  311  and the third transmission belt  321  through the second pulley  31  and the third pulley  32  to bring the third casing  12  to move. The first casing  10  and the third casing  12  are risen synchronously. This helps the user to operate the lift mechanism  2  with ease. Furthermore, when the gear unit  20  is turned in an opposite direction, the threaded rod  21  will be driven to rotate and move with respect to the sleeve  22 . The first casing  10  is linked to move with respect to the third casing  12 , with the first transmission belt  301  through the first pulley  30  to bring the third casing  12  to move. The first casing  10  and the third casing  12  are descended synchronously. 
         [0025]    Referring to  FIGS. 2 through 5 , the gear unit  20  comprises a driving gear  201  and a driven gear  202 . The driven gear  202  is disposed at the upper end of the threaded rod  21 . The driving gear  201  meshes with the driven gear  202 . The driving gear  201  is connected with a driving device to drive the gear unit  20  for driving the lift mechanism  2 . The driving device may be a handle H or an electric motor M. 
         [0026]      FIG. 6  and  FIG. 7  show another embodiment of the lift mechanism  2 . The gear unit  20  of the lift mechanism  2  is disposed at the upper end of the first casing  10 . The upper end of the sleeve  22  is connected with the driven gear  202 , and the lower end of the sleeve  22  is connected with the nut  23 . The upper end of the threaded rod  21  is inserted through the nut  23  and screwed into the sleeve  22 , and the lower end of the threaded rod  21  is connected to the carrying base  24 . As shown in  FIG. 6 , the carrying base  24  is connected to the second casing  11 . As shown in  FIG. 7 , the carrying base  24  is connected to the third casing  12 . 
         [0027]    The connection of the lift mechanism  2  may be in the form of the threaded rod  21  connected to the driven gear  202  and screwed into the sleeve  22 , or in the form of the sleeve  22  connected to the driven gear  202  and the threaded rod  21  screwed into the sleeve  22 . 
         [0028]    Referring to  FIG. 8  and  FIG. 9 , the support  1  may be provided with a linking rod L to connect with another support  1  in series. The linking rod L is connected with the driving gear  201 . The driven gear  202  is connected with the driving device. The driving device is the handle H, as shown in  FIG. 8 , or the electric motor M, as shown in  FIG. 9 . 
         [0029]    Although particular embodiments of the present invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be limited except as by the appended claims.