Adjustment Device for Chairs

Abstract

The adjustment device for chairs includes a support assembly, a support arm, a telescopic post and a backrest support. The support assembly has a tube and a fastener penetrating the tube. The tube is provided with a plurality of positioning holes longitudinally arranged in a row. An end of the support arm connects to the tube and is provided with a positioning bolt penetrating one of the positioning holes, and the other end is adapted to connect a cushion. The telescopic post is slidably accommodated in the tube and provided with a plurality of adjusting holes longitudinally arranged in a row for being selectively penetrated by the fastener. The backrest support is connected to the telescopic post for being moved with the telescopic post.

1 . An adjustment device for chairs, comprising:
 a support assembly, having a tube and a fastener penetrating the tube, and the tube being provided with a plurality of positioning holes longitudinally arranged in a row;   a support arm, an end of the support arm being connected to the tube and being provided with a positioning bolt penetrating one of the positioning holes, and the other end of the support arm being adapted to connect a cushion;   a telescopic post, slidably accommodated in the tube, being provided with a plurality of adjusting holes longitudinally arranged in a row for being selectively penetrated by the fastener; and   a backrest support connecting between a backrest and the telescopic post.   
     
     
         2 . The adjustment device of  claim 1 , wherein the support arm further comprises a connecting ring around the tube and the positioning bolt is disposed at the connecting ring. 
     
     
         3 . The adjustment device of  claim 1 , wherein a sleeve is accommodated in the tube, an end of the sleeve is formed with a flange hanging on the tube, and an inside of the sleeve is provided with two longitudinally opposite rails. 
     
     
         4 . The adjustment device of  claim 3 , wherein the telescopic post is formed with two longitudinal troughs for being engaged by the rails, and the adjusting holes are located in one of the troughs. 
     
     
         5 . The adjustment device of  claim 3 , wherein the sleeve is provided with a through hole penetrating one of the rails for being selectively penetrated by the fastener. 
     
     
         6 . The adjustment device of  claim 4 , wherein the sleeve is provided with a through hole penetrating one of the rails for being selectively penetrated by the fastener. 
     
     
         7 . The adjustment device of  claim 4 , further comprising a stopper ring at a lower end of the telescopic post for encompassing the troughs  51 . 
     
     
         8 . The adjustment device of  claim 1 , wherein the backrest support has two opposite ends, the two ends are provided with a first connecting portion for fastening to the telescopic post and a second connecting portion for linking the backrest respectively, and a curved portion is formed between the first connecting portion and the second connecting portion. 
     
     
         9 . The adjustment device of  claim 8 , further comprising a handle ring on the first connecting portion. 
     
     
         10 . The adjustment device of  claim 8 , wherein the second connecting portion is a pivot rotatably connecting the backrest.