Patent Publication Number: US-10758036-B2

Title: Adjustable table leg

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a table, and more particularly to an adjustable table leg. 
     2. Description of the Prior Art 
     A table is very common office equipment in the office. Most office tables are fixed and cannot be adjusted. They can&#39;t adapt to the changes in the office environment and the needs of the users. This makes the staff feel tired during work time and the office resources are not used effectively. Therefore, an adjustable table is developed accordingly. Most of conventional adjustable tables drive a lead screw through a motor to realize the upward and downward adjustment of the table. Due to the poor rationality of the structural design, the transmission of the lifting structure is unstable, and the stress of the linkage structure is excessive, resulting in fatigue and other issues. Moreover, the installation of the conventional adjustable table leg structure is troublesome, which limits the manufacturing efficiency. 
     Accordingly, the inventor of the present invention has devoted himself based on his many years of practical experiences to solve these problems. 
     SUMMARY OF THE INVENTION 
     In view of the drawbacks of the prior art, the primary object of the present invention is to provide an adjustable table leg. The structural design of which is ingenious and reasonable so as to solve the problems that the transmission structure of the prior art is unstable, and the stress of the linkage structure is too large, and it is easy to appear fatigue and other issues. 
     In order to achieve the above object, the present invention adopts the following technical solutions: 
     An adjustable table leg comprises a leg outer pipe, a leg middle pipe, a lead screw outer pipe, a lead screw inner pipe, an outer lead screw, an inner lead screw, an outer lead screw nut, an inner lead screw nut, a motor casing, and a drive motor. 
     The drive motor is mounted in the motor casing. An upper end of the inner lead screw is connected to the drive motor. A lower end of the inner lead screw is located in the outer lead screw. The lead screw outer pipe is configured to wrap the lead screw inner pipe. The leg middle pipe is configured to wrap the lead screw outer pipe. The leg outer pipe is configured to wrap the leg middle pipe. The outer lead screw nut is disposed outside the outer lead screw. The inner lead screw nut is disposed outside the inner lead screw. An upper end of the outer lead screw is connected with a first bearing. One end of the first bearing is connected to the inner lead screw nut. Another end of the first bearing is located above the outer lead screw nut. The inner lead screw is further connected with an inner lead screw guiding block. The inner lead screw guiding block is connected to the outer lead screw so that the outer lead screw, the inner lead screw guiding block and the inner lead screw are rotated synchronously. 
     One end of the lead screw outer pipe is connected to the inner lead screw nut. Another end of the lead screw outer pipe is connected to the leg middle pipe through a lead screw outer pipe fixing seat. One end of the lead screw inner pipe is connected to the outer lead screw nut. Another end of the lead screw inner pipe is connected with a lead screw inner pipe fixing seat. The leg outer pipe is connected to the lead screw inner pipe fixing seat through a connecting plate. 
     When the table leg is adjusted up and down, the drive motor drives the inner lead screw to rotate, and the inner lead screw drives the inner lead screw nut to move up and down along the inner lead screw relative to the motor casing, and the inner lead screw nut links the lead screw outer pipe to move up and down relative to the motor casing, and the lead screw outer pipe through the lead screw outer pipe fixing seat links the leg middle pipe to move up and down synchronously relative to the motor casing; meanwhile, the inner lead screw drives the inner lead screw guiding block to rotate, and the inner lead screw guiding block drives the outer lead screw to rotate, and the outer lead screw drives the outer lead screw nut to move up and down along the outer lead screw relative to the motor casing, and the outer lead screw nut links the lead screw inner pipe to move up and down relative to the motor casing, and the lead screw inner pipe links the leg outer pipe to move up and down synchronously relative to the motor casing through the lead screw inner pipe fixing seat and the connecting plate. 
     Preferably, a leg inner pipe is provided in the leg middle pipe. The leg inner pipe is configured to wrap the lead screw outer pipe. One end of the leg inner pipe is connected to the motor casing. 
     Preferably, the first bearing is mounted on a first bearing fixing seat. The upper end of the outer lead screw is provided with an annular limiting groove. Upper and lower ends of the annular limiting groove have a first limiting surface and a second limiting surface, respectively. Upper and lower ends of the first bearing abut the first limiting surface and the second limiting surface, respectively. An outer sidewall of the first bearing is exposed outside the annular limiting groove. An inner side of the first bearing fixing seat has a positioning step. The outer side wall of the first bearing is positioned at the positioning step. An upper end of the first bearing fixing seat is fixedly connected to the inner lead screw nut. A lower end of the first bearing fixing seat is located above the outer lead screw nut. 
     Preferably, the upper end of the inner lead screw is connected with a second bearing. The second bearing is mounted on a second bearing fixing seat. One end of the second bearing fixing seat is connected to the motor casing. Another end of the second bearing fixing seat abuts against the inner lead screw nut. 
     Preferably, the upper end of the inner lead screw is further connected with a lead screw engaging disk. A lead screw assembly fixing plate is disposed outside the lead screw engaging disk. The lead screw assembly fixing plate is mounted in the motor casing. The lead screw assembly fixing plate is provided with a through hole. One end of the lead screw engaging disk is located in the motor casing. Another end of the lead screw engaging disk passes through the through hole to abut against the second bearing. 
     Preferably, a first leg spacing frame is connected to one end of the leg outer pipe. An outer side wall and an inner side wall of the first leg spacing frame are attached to an inner side wall of the leg outer pipe and an outer side wall of the leg middle pipe, respectively. A second leg spacing frame is connected to one end of the leg middle pipe. An outer side wall and an inner side wall of the second leg spacing frame are attached to an inner side wall of the leg middle pipe and an outer side wall of the leg inner pipe, respectively. 
     Preferably, an outer side wall of the inner lead screw guiding block is provided with a plurality of guiding ribs. An inner side wall of the outer lead screw is provided with a plurality of guiding grooves. The guiding ribs are fitted in the corresponding guiding grooves. 
     Preferably, an outer lead screw stopper is connected to a lower end of the outer lead screw. The outer lead screw stopper includes a first portion and a second portion connected to each other. The first portion and the second portion each have a first connecting end and a second connecting end. The first connecting end and the second connecting end are a connecting hole and a connecting post, respectively. The connecting post is fitted into the corresponding connecting hole. 
     Preferably, the end of the leg inner pipe is connected with two first leg long spacers and two first leg short spacers. The two first leg long spacers and the two first leg short spacers are all mounted on an outer side of the leg inner pipe. The first leg long spacers and the first leg short spacers are arranged on the leg inner pipe in an alternating manner. 
     Preferably, one end of the leg middle pipe, connected to the lead screw outer pipe fixing seat, is connected with two second leg long spacers and two second leg short spacers. The two second leg long spacers and the two second leg short spacers are all mounted on an outer side of the leg middle pipe. The second leg long spacer and the second leg short spacer are arranged on the leg middle pipe in an alternating manner. A positioning post is disposed on one side of each of the two second leg long spacers and the two second leg short spacers. The positioning post passes through the leg middle pipe and is engaged in an engaging hole of the lead screw outer pipe fixing seat. 
     The present invention has obvious advantages and beneficial effects compared with the prior art, in particular, it can be known from the above technical solutions. The inner lead screw links the inner lead screw nut to move the outer lead screw nut along the outer lead screw, so that the inner lead screw nut drives the lead screw outer pipe to link the leg middle pipe and the outer lead screw nut to drive the lead screw inner pipe to move the leg outer pipe up and down synchronously. Therefore, the upward and downward transmission is more stable, the upward and downward adjustment is smoother, the phenomenon of jamming does not occur, the adjustment precision is higher, the stress of the inner lead screw nut and the outer lead screw nut is more uniform, the fatigue degree is reduced, and the service life is increased. In particular, its structural design is ingenious, the overall layout is reasonable, and the installation is simple. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a structural schematic view according to an embodiment of the present invention (in a retracted state); 
         FIG. 2  is an exploded view according to the embodiment of the present invention; 
         FIG. 3  is a cross-sectional view according to the embodiment of the present invention (in a retracted state); 
         FIG. 4  is a partial structural view of  FIG. 3 ; 
         FIG. 5  is another partial structural view of  FIG. 3 ; 
         FIG. 6  is a schematic view according to the embodiment of the present invention (in an extended state); and 
         FIG. 7  is a partially exploded view of the embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Please refer to  FIG. 1  to  FIG. 7 , which shows a specific structure of an embodiment of the present invention; it is mainly applied to an office table, but is not limited to an office table, and may be applied to a desk, a dining table, and the like. 
     Spatially relative terms, such as “upper,” “lower,” and the like, may be used herein for ease of explanation to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or in operation, in addition to the orientation depicted in the figures. Therefore, it should not be construed as limiting the invention. 
     An adjustable table leg in accordance with an embodiment of the present invention comprises a leg outer pipe  1 , a leg middle pipe  2 , a lead screw outer pipe  4 , a lead screw inner pipe  5 , an outer lead screw  6 , an inner lead screw  7 , an outer lead screw nut  8 , an inner lead screw nut  9 , a motor casing  10 , and a drive motor  11 . The drive motor  11  is mounted in the motor casing  10 . The motor casing  10  has a motor cover  101 . An upper end of the inner lead screw  7  is connected to the drive motor  11 , and a lower end of the inner lead screw  7  is located in the outer lead screw  6 . The lead screw outer pipe  4  is configured to wrap the lead screw inner pipe  5 . The leg middle pipe  2  is configured to wrap the lead screw outer pipe  4 . The leg outer pipe  1  is configured to wrap the leg middle pipe  2 . The outer lead screw nut  8  is disposed outside the outer lead screw  6 . The inner lead screw nut  9  is disposed outside the inner lead screw  7 . An upper end of the outer lead screw  6  is connected with a first bearing  13 . One end of the first bearing  13  is connected to the inner lead screw nut  9 , and another end of the first bearing  13  is located above the outer lead screw nut  8 . The inner lead screw  7  is further connected with an inner lead screw guiding block  20 , and the inner lead screw guiding block  20  is connected to the outer lead screw  6 , so that the outer lead screw  6 , the inner lead screw guiding block  20  and the inner lead screw  7  are rotated synchronously. A leg inner pipe  3  is provided in the leg middle pipe  2 . The leg inner pipe  3  is configured to wrap the lead screw outer pipe  4 . A first end of the leg inner pipe  3  is connected to the motor casing  10 . In this embodiment, the leg inner pipe  3  is integrally connected with the motor casing  10 . One end of the lead screw outer pipe  4  is connected to the inner lead screw nut  9 , and another end of the lead screw outer pipe  4  is connected to the leg middle pipe  2  through a lead screw outer pipe fixing seat  26 . A first end of the lead screw inner pipe  5  is connected to the outer lead screw nut  8 . A second end of the lead screw inner pipe  5  is connected with a lead screw inner pipe fixing seat  27 . The leg outer pipe  1  is connected to the lead screw inner pipe fixing seat  27  through a connecting plate  28 . 
     Wherein, the upper end of the inner lead screw  7  is connected with a second bearing  12 . The second bearing  12  is mounted on a second bearing fixing seat  14 . One end of the second bearing fixing seat  14  is connected to the motor casing  10 , and another end of the second bearing fixing seat  14  abuts against the inner lead screw nut  9 . The upper end of the inner lead screw  7  is further connected with a lead screw engaging disk  16 . A lead screw assembly fixing plate  17  is disposed outside the lead screw engaging disk  16 . The lead screw assembly fixing plate  17  is mounted in the motor casing  10 . The lead screw assembly fixing plate  17  is provided with a through hole  171 . One end of the lead screw engaging disk  16  is located in the motor casing  10 , and another end of the lead screw engaging disk  16  passes through the through hole  171  to abut against the second bearing  12 . 
     The first bearing  13  is mounted on a first bearing fixing seat  15 . The upper end of the outer lead screw  6  is provided with an annular limiting groove  601 . The upper and lower ends of the annular limiting groove  601  have a first limiting surface and a second limiting surface, respectively. The upper and lower ends of the first bearing  13  abut the first limiting surface and the second limiting surface, respectively. The outer sidewall of the first bearing  13  is exposed outside the annular limiting groove  601 . The inner side of the first bearing fixing seat  15  has a positioning step. The outer side wall of the first bearing  13  is positioned at the positioning step. The upper end of the first bearing fixing seat  15  is fixedly connected to the inner lead screw nut  9 , and the lower end of the first bearing fixing seat  15  is located above the outer lead screw nut  8 . Thereby, the linkage between the inner lead screw nut  9  and the outer lead screw  6  can ensure the synchronous movement of the same track between the inner lead screw nut  9  and the outer lead screw  6  when moved up and down. 
     A first leg spacing frame  18  is connected to the upper end of the leg outer pipe  1 . The outer side wall and the inner side wall of the first leg spacing frame  18  are attached to the inner side wall of the leg outer pipe  1  and the outer side wall of the leg middle pipe  2 , respectively. A second leg spacing frame  19  is connected to the upper end of the leg middle pipe  2 . The outer side wall and the inner side wall of the second leg spacing frame  19  are attached to the inner side wall of the leg middle pipe  2  and the outer side wall of the leg inner pipe  3 , respectively. The first leg spacing frame  18  and the second leg spacing frame  19  can effectively ensure the intervals between the leg outer pipe  1 , the leg middle pipe  2 , and the leg inner pipe  3 , thereby facilitating the upward movement and the downward movement of the table leg. 
     In this embodiment, preferably, the inner lead screw guiding block  20  is connected to the lower end of the inner lead screw  7  so that the stroke of the outer lead screw  6  relative to the inner lead screw  7  is sufficiently long to avoid a waste of the length of the lead screw. The outer side wall of the inner lead screw guiding block  20  is provided with a plurality of guiding ribs  201 . Correspondingly, the inner side wall of the outer lead screw  6  is provided with a plurality of guiding grooves  602 . The guiding ribs  201  are fitted in the corresponding guiding grooves  602 . The plurality of guiding ribs  201  are vertically protruded from the outer side wall of the inner lead screw guiding block  20 . The plurality of guiding grooves  602  are vertically recessed on the inner side wall of the outer lead screw  6 . 
     An outer lead screw stopper  21  is connected to the lower end of the outer lead screw  6 . The outer lead screw stopper  21  includes a first portion and a second portion connected to each other. The first portion and the second portion each have a first connecting end and a second connecting end. The first connecting end and the second connecting end are a connecting hole and a connecting post, respectively. The connecting post is fitted into the corresponding connecting hole. 
     In addition, in the embodiment, the upper end of the leg inner pipe  3  is connected with two first leg long spacers  22  and two first leg short spacers  24 . The two first leg long spacers  22  and the two first leg short spacers  24  are all mounted on the outer side of the leg inner pipe  3 . The first leg long spacers  22  and the first leg short spacers  24  are arranged on the leg inner pipe  3  in an alternating manner. One end of the leg middle pipe  2 , connected to the lead screw outer pipe fixing seat  26 , is connected with two second leg long spacers  23  and two second leg short spacers  25 . The two second leg long spacers  23  and the two second leg short spacers  25  are all mounted on the outer side of the leg middle pipe  2 . The second leg long spacer  23  and the second leg short spacer  25  are arranged on the leg middle pipe  2  in an alternating manner. A positioning post  202  is disposed on one side of each of the two second leg long spacers  23  and the two second leg short spacers  25 . The positioning post  2022  passes through the leg middle pipe  2  and is engaged in an engaging hole  261  of the lead screw outer pipe fixing seat  26 . Thereby, the arrangement of the two first leg long spacers  22 , the two first leg short spacers  24 , the two second leg long spacers  23  and the two second leg short spacers  25  can effectively ensure the intervals between the leg outer pipe  1 , the leg middle pipe  2 , and the leg inner pipe  3 , thereby facilitating the upward movement and the downward movement of the table leg. Besides, the positioning post  202  is inserted into the engaging hole  261  of the lead screw outer pipe fixing seat  26 , so that the leg middle pipe  2  and the lead screw outer pipe  4  can be stably connected together to move upwardly and downwardly simultaneously. The snap-type positioning structure is simple and easy for installation. 
     The working principle of the present invention is as follows: 
     When the table leg is adjusted up and down, the drive motor  11  drives the inner lead screw  7  to rotate, and the inner lead screw  7  drives the inner lead screw nut  9  to move up and down along the inner lead screw  7  relative to the motor casing  10 , and the inner lead screw nut  9  links the lead screw outer pipe  4  to move up and down relative to the motor casing  10 , and the lead screw outer pipe  4  through the lead screw outer pipe fixing seat  26  links the leg middle pipe  2  to move up and down synchronously relative to the motor casing  10 ; meanwhile, the inner lead screw  7  drives the inner lead screw guiding block  20  to rotate, and the inner lead screw guiding block  20  drives the outer lead screw  6  to rotate, and the outer lead screw  6  drives the outer lead screw nut  8  to move up and down along the outer lead screw  6  relative to the motor casing  10 , and the outer lead screw nut  8  links the lead screw inner pipe  5  to move up and down relative to the motor casing  10 , and the lead screw inner pipe  5  links the leg outer pipe  1  to move up and down synchronously relative to the motor casing  10  through the lead screw inner pipe fixing seat  27  and the connecting plate  28 . 
     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