Abstract:
A height adjustment assembly for furniture has a control member automatically engaging a movable member of a piece of furniture by gravity, so as to hold the movable member at a desired height. When operated, the control member releases the movable member so that the height of the furniture can be readjusted and reset.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to modulized components for adjusting height of furniture, and more particularly, to a height adjustment assembly applicable to furniture. 
     2. Description of Related Art 
     Telescoped tubes are conventionally used as the approach to allowing height adjustment of furniture. Taking one known adjustment assembly of a table for example, an outer tube may be fixed to a brace of the table while an inner tube telescoped with the outer tube may be coupled with a tabletop plate, so that when the inner tube shifts inside the outer tube, the altitude of the tabletop plate is changed with respect to the brace. One or more manually operatable screw bolt may be provided on the outer tube to pierce into a hole formed on the inner tube so as to position the inner tube with respect to the outer tube, thereby holding the tabletop plate at the desired height. 
     However, when using the conventional adjustment approach implementing telescoped tubes and bolts, a user has to repeatedly screw and unscrew the bolts. Especially, when any piece of furniture uses two or more such adjustment assemblies for its two or more legs, each said one has to be adjusted separately. Thus, not only is the operation time-consuming, but also the inconsistent adjustment of the plural adjustment assemblies causes an inclined top surface of the furniture. Hence, there is a need for an improved height adjustment assembly that is convenient and effective to operate. 
     SUMMARY OF THE INVENTION 
     In view of the shortcomings of the prior art, one objective of the present invention is to provide a height adjustment assembly for furniture, by using which height adjustment assembly, a height of a piece of furniture being adjustable. 
     Another objective of the present invention is to provide a height adjustment assembly for furniture, wherein the height adjustment assembly has a control member automatically engaging a movable member of a piece of furniture by gravity, so as to hold the movable member at a desired height. When the control member is pulled upward, the control member of the height adjustment assembly and the movable member of the furniture are disengaged so as to allow the movable member to move vertically along the furniture. 
     To achieve these and other objectives of the present invention, the disclosed height adjustment assembly comprises: a connecting member rotatably connected with a vertical portion of a piece of furniture; and a controlling plate connected with the connecting member so that the controlling plate is allowed to swing between a first position and a second position against the connecting member, the controlling plate having: at least one coupling portion, partially contacting a movable member of the furniture; at least a retaining portion, when the controlling plate is at the first position, piercing into a hole formed on the movable member; and at least an operating portion, for a user to hold and pull the controlling plate to the second position from the first position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention as well as a preferred mode of use, further objectives and advantages thereof will be best understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawing, wherein: 
         FIG. 1  is a perspective view of a table equipped with a height adjustment assembly of the present invention, wherein a tabletop plate of the table is held at a first height by the height adjustment assembly; 
         FIG. 2  is a perspective view of the height adjustment assembly of the present invention; 
         FIG. 3  is a partial perspective view of the table of  FIG. 1 , wherein a movable member of the table is fastened; 
         FIG. 4  is a partial perspective view of the table of  FIG. 1 , wherein the movable member of the table is released; 
         FIG. 5  is a schematic drawing showing the movable member is retained by the height adjustment assembly; 
         FIG. 6  is a schematic drawing showing the movable member is released from the height adjustment assembly; and 
         FIG. 7  is a perspective view of the table equipped with the height adjustment assembly of the present invention, wherein the tabletop plate of the table is held at a second height by the height adjustment assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     While a preferred embodiment provided hereinafter for illustrating the concept of the present invention as described above, it is to be understood that the components of the embodiment shown in the accompanying drawings are depicted for the sake of easy explanation and need not to be made in scale. 
     Referring to  FIG. 1  for an exemplificative piece of furniture where a height adjustment assembly of the present invention is adapted. The furniture is herein a table includes a brace  10  that has a vertical portion  11 . A movable member  20  is such attached to the vertical portion  11  that the movable member  20  can vertically move with respect to the vertical portion  11 . In the present embodiment shown in the drawings, the movable member  20  is fixed atop with a tabletop plate  30 . A height adjustment assembly  40  of the present invention is assembled to the brace  10  and corresponding to the movable member  20  for a user to operate. The height adjustment assembly  40  normally at a first position can be posed to a second position by the user&#39;s operation. The height adjustment assembly  40 , at the first position, serves to fix and retain the movable member  20  from moving vertically. The height adjustment assembly  40 , at the second position, releases the movable member  20  so as to allow the movable member  20  to move vertically, thereby changing a height of the tabletop plate  30 . 
     The brace  10  includes a horizontal base  12  that has one end coupled with a lower end of the vertical portion  11 . The vertical portion  11  is constructed from two parallel stems  111 . Besides, a plurality of universal wheels  13  for facilitating movement of the brace  10 . A fixing member  14  is provided on the vertical portion  11  for receiving a part of the movable member  20 . A handle car  15  is mounted top the vertical portion  11  and extending away from the fixing member  14 . According to the drawings, the movable member  20  includes two parallel rods  21  while the fixing member  14  includes two tubes  141 , wherein each said rod  21  is fittingly received by a respective said tube  141  so that the rods are stably located in the tube  141  without swing. 
     Referring to  FIGS. 2 and 3 , the height adjustment assembly  40  primarily comprises a connecting member  41  and a controlling plate  42 . 
     The connecting member  41  is rotatably connected with the vertical portion  11 . In the present embodiment, the connecting member  41  is a shaft with two ends thereof pivotably coupled with the two stems  111 . 
     The controlling plate  42  is connected with the connecting member  41  in a bias manner. The controlling plate  42  has a coupling portion  43  fitting a part of the movable member  20 , a retaining portion  44  for engaging with the movable member  20 , and an operating portion  45  for a user to operate. Since the connecting member  41  is rotatably coupled with the vertical portion  111 , the controlling plate  42  is allowed to swing against the connecting member  41 . According to the present embodiment, the coupling portion  43  is a pair of through holes  431  formed on the controlling plate  42 . Each said through hole  431  has an inner diameter greater than a diameter of a corresponding said rod  21  of the movable member  20 . Moreover, a plurality of holes  22  is aligned vertically as a line on each said rod  21  of the movable member  20  while the retaining portion  44  is a pin  441  formed at a periphery of each of the through holes  431 . Stating differently, the pin  441  is configured for being inserted into any of the holes  22 . 
     As can be seen in  FIGS. 3 and 5 , since the controlling plate  42  is connected with the connecting member  41  in said bias manner, the height adjustment assembly  40  is normally posed at the first position where the controlling plate  42  slant downward upon the connecting member  41 . At this time, the coupling portion  43  and the rods  43  have their axes intersecting and including an angle smaller than 90 degrees. Consequently, the rods  21  and peripheries of the through holes  431  are interfered with each other. Meantime, the pins  441  are inserted to corresponding said holes  22  on the rods  21 . As a result, the rods  21  are restricted from moving vertically in the tubes  141  and the height of the tabletop plate  30  is fixed. 
     Referring to  FIGS. 4 and 6 , to change the height of the tabletop plate  30 , a user may hold the operating portion  45  to pull the controlling plate  42  upward to a horizontal position, namely the second position. At this time, the coupling portion  43  and the rods  21  have their axes intersecting and including an angle equal to 90 degrees. Consequently, interference between the rods  21  and the peripheries of the through holes  431  is relieved. Thus, the pins  441  leave the holes  22  so that the rods  21  are allowed to move vertically in the tubes  141  and through the through holes  431 , thereby realizing height adjustment of the tabletop plate  30 . 
     By comparing the perspective views of the table as shown  FIG. 1  and  FIG. 7 , it is clear that the tabletop plate  30  is higher in  FIG. 1  than in  FIG. 7 . 
     The present invention has been described with reference to the preferred embodiment and it is understood that the embodiment is not intended to limit the scope of the present invention. Moreover, as the contents disclosed herein should be readily understood and can be implemented by a person skilled in the art, all equivalent changes or modifications which do not depart from the concept of the present invention should be encompassed by the appended claims.