Patent Publication Number: US-7210742-B2

Title: Distance adjustment device for chair

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a distance adjustment device, and more particularly to a distance adjustment device for a chair. 
   2. Description of the Related Art 
   A conventional distance adjustment device is mounted on a chair and comprises a guide rail fixed on a seat portion of the chair, and a movable plate is fixed on a backrest or an armrest of the chair and slidably mounted on the guide rail. Thus, the movable plate is movable relative to the guide rail so as to adjust the distance between the backrest or armrest and the seat portion. In operation, a user holds the guide rail by his one hand and applies a force on the movable plate by his other hand to drive the movable plate to move relative to the guide rail to adjust the relative position between the movable plate and the guide rail so as to adjust the distance between the backrest or armrest and the seat portion. However, the user has to operate the conventional distance adjustment device by his two hands, thereby causing inconvenience to the user in the distance adjustment, and thereby wasting the user&#39;s manual work. 
   SUMMARY OF THE INVENTION 
   In accordance with the present invention, there is provided a distance adjustment device, comprising a guide rail, a movable plate slidably mounted on the guide rail, a movable handle pivotally mounted on the movable plate and having a first end detachably engaged with the guide rail, and a fixed handle secured on the movable plate and located opposite to a second end of the movable handle. 
   The primary objective of the present invention is to provide a distance adjustment device that is operated easily and conveniently. 
   Another objective of the present invention is to provide a distance adjustment device, wherein the user only needs to hold the push portion of the movable handle and the grip portion of the fixed handle by his one hand to unlock and move the movable plate so as to adjust the relative position between the movable plate and the guide rail, so that the distance adjustment device is operated by the user&#39;s one hand, thereby facilitating the user adjusting the distance between the backrest (or the armrest) and the seat portion. 
   A further objective of the present invention is to provide a distance adjustment device, wherein the user only needs to push the push portion of the movable handle toward the grip portion of the fixed handle to unlock and move the movable plate, so that the movable plate is moved easily and rapidly, thereby facilitating the user operating the distance adjustment device. 
   A further objective of the present invention is to provide a distance adjustment device, wherein the movable plate is fixed on the guide rail automatically by the restoring force of the elastic member after the distance adjustment, thereby facilitating the user operating the distance adjustment device. 
   A further objective of the present invention is to provide a distance adjustment device having a simplified construction, thereby decreasing costs of fabrication. 
   Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a distance adjustment device for a chair in accordance with the preferred embodiment of the present invention; 
       FIG. 2  is a partially perspective view of the distance adjustment device as shown in  FIG. 1 ; 
       FIG. 3  is an exploded perspective view of the distance adjustment device as shown in  FIG. 1 ; 
       FIG. 4  is a schematic plan operational view of the distance adjustment device as shown in  FIG. 2 ; and 
       FIG. 5  is a schematic back plan operational view of the distance adjustment device as shown in  FIG. 2 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to the drawings and initially to  FIGS. 1–3 , a distance adjustment device for a chair in accordance with the preferred embodiment of the present invention comprises a guide rail  2 , a movable plate  1  slidably mounted on the guide rail  2 , a movable handle  11  pivotally mounted on the movable plate  1  and having a first end detachably engaged with the guide rail  2 , and a fixed handle  12  secured on the movable plate  1  and located opposite to a second end of the movable handle  11 . 
   The guide rail  2  has a side formed with a plurality of locking grooves  21  and has a surface formed with an elongated guide slot  22 . 
   The movable plate  1  has an end formed with a screw bore  151  for screwing a guide screw  15  which is slidably mounted in the guide slot  22  of the guide rail  2  to guide movement of the movable plate  1  on the guide rail  2 . The movable plate  1  has a periphery provided with a plurality of shock-absorbing blocks  161  rested on the guide rail  2  to provide a shock-absorbing effect to the movable plate  1 , thereby preventing the movable plate  1  from being vibrated during movement, so that the movable plate  1  is slidable on the guide rail  2  smoothly and stably. The periphery of the movable plate  1  is formed with a plurality of receiving recesses  16  to receive the shock-absorbing blocks  161 . 
   The first end of the movable handle  11  has a first side formed with a locking block  11   1  detachably locked in either one of the locking grooves  21  of the guide rail  2 . The second end of the movable handle  11  is provided with a push portion  110  protruded outward from the movable plate  1 . 
   The fixed handle  12  has a first end secured on the movable plate  1  and a second end provided with a grip portion  120  protruded outward from the movable plate  1  and located opposite to the push portion  110  of the movable handle  11 . 
   The distance adjustment device further comprises a support member  13  secured on the movable plate  1  and located between the movable handle  11  and the guide rail  2 , and an elastic member  14  biased between the support member  13  and a second side of the first end of the movable handle  11  to push the first end of the movable handle  11  toward the locking grooves  21  of the guide rail  2  so that the locking block  111  of the movable handle  11  is normally locked in one of the locking grooves  21  of the guide rail  2  by the elastic force of the elastic member  14 . The support member  13  has a side formed with a mounting recess  131  for mounting a first end of the elastic member  14 , and the second side of the first end of the movable handle  11  is provided with a mounting base  112  for mounting a second end of the elastic member  14 . A cover  3  is secured on the guide rail  2  to encompass the support member  13  and the elastic member  14 . 
   In operation, referring to  FIGS. 1–5 , when a user&#39;s one hand exerts a force on the push portion  110  of the movable handle  11  and the grip portion  120  of the fixed handle  12 , the push portion  110  of the movable handle  11  is pushed to move toward the grip portion  120  of the fixed handle  12 , so that the movable handle  11  is pivoted on the movable plate  1  to drive the locking block  111  of the movable handle  11  to move outward relative to the locking grooves  21  of the guide rail  2 , thereby detaching the locking block  111  of the movable handle  11  from the locking grooves  21  of the guide rail  2  so as to unlock the movable plate  1  from the guide rail  2 . Thus, the movable plate  1  is movable relative to the guide rail  2  freely so as to adjust the position between the movable plate  1  and the guide rail  2 . 
   After adjustment, the force applied on the push portion  110  of the movable handle  11  and the grip portion  120  of the fixed handle  12  is removed to release the movable handle  11 , so that the locking block  111  of the movable handle  11  is pushed to be locked in another one of the locking grooves  21  of the guide rail  2  by the restoring force of the elastic member  14 , thereby locking the movable plate  1  on the guide rail  2 . Thus, the movable plate  1  is fixed on the guide rail  2  automatically by the restoring force of the elastic member  14 . 
   In practice, when the distance adjustment device is mounted on a chair, the guide rail  2  is fixed on a seat portion of the chair, and the movable plate  1  is fixed on a backrest or an armrest of the chair. Thus, the movable plate  1  is movable relative to the guide rail  2  freely so as to adjust the distance between the backrest or armrest and the seat portion. 
   Accordingly, the user only needs to hold the push portion  110  of the movable handle  11  and the grip portion  120  of the fixed handle  12  by his one hand to unlock and move the movable plate  1  so as to adjust the relative position between the movable plate  1  and the guide rail  2 , so that the distance adjustment device is operated by the user&#39;s one hand, thereby facilitating the user adjusting the distance between the backrest (or the armrest) and the seat portion. In addition, the user only needs to push the push portion  110  of the movable handle  11  toward the grip portion  120  of the fixed handle  12  to unlock and move the movable plate  1 , so that the movable plate  1  is moved easily and rapidly, thereby facilitating the user operating the distance adjustment device. Further, the movable plate  1  is fixed on the guide rail  2  automatically by the restoring force of the elastic member  14  after the distance adjustment, thereby facilitating the user operating the distance adjustment device. Further, the distance adjustment device has a simplified construction, thereby decreasing costs of fabrication. 
   Although the invention has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention.