Patent Publication Number: US-6698840-B1

Title: Chair with a detachable backrest

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a chair, more particularly to a chair with a detachable backrest. 
     2. Description of the Related Art 
     Referring to FIG. 1, a conventional chair is shown to include a seat  11  having opposing front and rear ends, left and right armrest members  12  disposed uprightly on opposite sides of the seat  11 , a footrest  15  that extends downwardly and frontwardly from the front end of the seat  11 , and a backrest  13  which extends upwardly and rearwardly from the rear end of the seat  11 . 
     The conventional chair is bulky, and is thus inconvenient to transport or store. 
     SUMMARY OF THE INVENTION 
     Therefore, the object of this invention is to provide a chair with a detachable backrest so as to facilitate transport and storage therereof. 
     Accordingly, a chair according to the present invention includes: a seat having a rear portion with two opposite sides; a backrest disposed rearwardly of the seat and having a lower portion with two opposite sides respectively disposed proximate to the opposite sides of the rear portion of the seat; and a coupling unit. The coupling unit includes a pair of spaced apart engaging tongues, a pair of brackets, and a pair of fastener clips. The engaging tongues are respectively fixed on and extend outwardly from the opposite sides of one of the rear portion of the seat and the lower portion of the backrest, respectively. Each of the engaging tongues has a distal end that is formed with an engaging hole confined by a hole-defining wall. The brackets are respectively fixed on the opposite sides of the other one of the rear portion of the seat and the lower portion of the backrest. Each of the brackets defines a tongue-retention channel that extends in a longitudinal direction and that has a mounting end and an inlet end opposite to the mounting end. Each of the engaging tongues is snugly insertable into the tongue-retention channel of a respective one of the backrests via the inlet end. The fastener clips are mounted respectively on the brackets. Each of the fastener clips includes a resilient arm that extends from the mounting end toward the inlet end and that has a V-shaped engaging end distal from the mounting end and projecting in a transverse direction relative to the longitudinal direction into the tongue-retention channel of the respective one of the backrests. The V-shaped engaging end defines an abutment side face and a sliding side face that is opposite to and that extends from the abutment side face, and that is inclined relative to the longitudinal direction. The V-shaped engaging end is resiliently movable relative to the tongue-retention channel such that the V-shaped engaging end resiliently moves in the transverse direction away from the tongue-retention channel of a respective one of the backrests when a respective one of the engaging tongues slides over the sliding side face upon insertion of the respective one of the engaging tongues into the tongue-retention channel of the respective one of the backrests, and such that the V-shaped engaging end resiliently moves toward the tongue-retention channel of the respective one of and into the engaging hole in the respective one of the engaging tongues when the respective one of the engaging tongues passes over the sliding side face to the abutment side face. The abutment side face engages the hole-defining wall of the engaging hole when the respective one of the engaging tongues is pulled away from the tongue-retention channel of the respective one of the backrests so as to prevent undesired removal of the respective one of the engaging tongues from the tongue-retention channel of the respective one of the backrests. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and advantages of this invention will become more apparent in the following detailed description of the preferred embodiment of this invention, with reference to the accompanying drawings, in which: 
     FIG. 1 is a perspective view of a conventional chair; 
     FIG. 2 is a perspective view of the preferred embodiment of a chair according to the present invention; 
     FIG. 3 is a partly exploded view of the preferred embodiment; 
     FIG. 4 illustrates how an engaging tongue of a seat is inserted into a tongue-retention channel formed on a backrest of the preferred embodiment; 
     FIG. 5 is a partly sectional view of the backrest of the preferred embodiment, illustrating a position of a fastener clip prior to insertion of the engaging tongue into the tongue-retention channel; and 
     FIG. 6 is a partly sectional view of the backrest of the preferred embodiment, illustrating a position of the fastener clip after insertion of the engaging tongue into the tongue-retention channel. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 2 to  6 , the preferred embodiment of a chair according to the present invention is shown to include a seat  21 , a backrest  3 , and a coupling unit  4 . 
     As illustrated, the seat  21  has a rear portion  21 ″ with two opposite sides, a front portion  212  and a footrest  22  disposed frontwardly of the front portion  212 . 
     The backrest  3  is disposed rearwardly of the seat  21 , and has a lower portion  31  with two opposite sides  31 ″ respectively disposed proximate to the opposite sides of the rear portion  21 ″ of the seat  21 . 
     The coupling unit  4  includes a pair of spaced apart engaging tongues  214 , a pair of brackets  5 , and a pair of fastener clips  6 . The engaging tongues  214  are fixed on and extend outwardly from the opposite sides of the rear portion  21 ″ of the seat  21 , respectively. Each of the engaging tongues  214  has a distal end that is formed with an engaging hole  215  confined by a hole-defining wall  215 W. The brackets  5  are respectively fixed on the opposite sides of the lower portion  31  of the backrest  3 . Each of the brackets  5  defines a tongue-retention channel  53  that extends in a longitudinal direction and that has a mounting end  53 M and an inlet end  53 I opposite to the mounting end  53 M. Each of the engaging tongues  214  is snugly insertable into a respective one of the tongue-retention channels  53  of the backrests  5  via the inlet end  53 I. The fastener clips  6  are mounted respectively on the brackets  5 . Each of the fastener clips  6  includes a resilient arm  63  that extends from the mounting end  53 M toward the inlet end  53 I and that has an inverted U-shaped mounting portion  61  mounted on the mounting end  53 M, and a V-shaped engaging end  64  distal from the mounting end  53 M and projecting in a transverse direction relative to the longitudinal direction into the tongue-retention channel  53 . The V-shaped engaging end  64  defines an abutment side face  641  and a sliding side face  642  that is opposite to and that extends from the abutment side face  641  and that is inclined relative to the longitudinal direction. The V-shaped engaging end  64  is resiliently movable relative to the respective tongue-retention channel  53  such that the V-shaped engaging end  64  resiliently moves in the transverse direction away from the respective tongue-retention channel  53  when a respective one of the engaging tongues  214  slides over the sliding side face  642  upon insertion of the respective engaging tongues  214  into the respective tongue-retention channel  53 , and such that the V-shaped engaging end  64  resiliently moves toward the respective tongue-retention channel  53  and into the engaging hole  215  when the respective one of the engaging tongues  214  passes over the sliding side face  642  to the abutment side face  641  (see FIG.  6 ). The abutment side face  641  engages the hole-defining wall  215 W of the engaging hole  215  when the respective one of the engaging tongues  214  is pulled away from the tongue-retention channel  53  (see FIG.  5 ). Thus, undesired removal of the engaging tongues  214  from the tongue-retention channels  53  of the backrests  5  is prevented. The backrest  3  can be detached from the seat  21  by simply pulling the V-shaped engaging ends  64  of the resilient arms  63  of the fastener clips  6  from the engaging holes  215  in the engaging tongues  214  so as to permit removal of the engaging tongues  214  from the tongue-retention channels  53  of the backrests  5 . 
     In this embodiment, each of the brackets  5  includes a mounting wall  51  that is fixed on one of the two opposing sides  31 ″ of the backrest  3 , that extends in the longitudinal direction, and that has two side edges, and two spaced-apart generally L-shaped flanges  52  which are fixed on and extend from the side edges of the mounting wall  51 , respectively, to confine the respective tongue-retention channel  53 . 
     The mounting wall  51  has upper and lower portions  511  which are indented to form upper and lower holes  512 . The inverted U-shaped mounting portion  61  of each of the fastener clips  6  is formed with a through hole  621  that is aligned with the upper hole  512  in the mounting wall  51 . An upper screw  513  extends through the through hole  621  and the upper hole  512 , and is threaded on the respective one of the opposite sides of the lower portion  31  of the backrest  3 , thereby securing the upper portion  511  of the mounting wall  51  on the lower portion  31  of the backrest  3 . A lower screw  513  extends through the lower screw hole  512  in the mounting wall  51 , and is threaded on the respective one of the opposite sides of the lower portion  31  of the backrest  3 , thereby securing the lower portion  511  of the mounting wall  51  on the lower portion  31  of the backrest  3 . 
     The seat  21  includes left and right vertical portions  211  disposed at opposite sides of the horizontal front portion  212 . A control device is disposed below the horizontal portion  212 , extends between the vertical portions  211 , and includes an operating lever  25  which is connected to the backrest  3  via a rear linkage unit  217  and which is connected to the footrest  22  via a front linkage unit  213 . As such rotation of the operating lever  25  results in synchronous movement of the backrest  3  and the footrest  22  relative to the front portion  212  to adjust inclination of the backrest  3  and the footrest  22  relative to the front portion  212 . Since the feature of the present invention does not reside in the control device, a detail description thereof is omitted herein for the sake of brevity. 
     With this invention thus explained, it is apparent that numerous modifications and variations can be made without departing from the scope and spirit of this invention. It is therefore intended that the invention be limited only as indicated in the appended claims.