Armrests adjustment device for a chair

Abstract

An armrests adjustment device for a chair is provided. The armrests adjustment device is to be assembled on a center column of a chair and installed with two armrests. The armrests adjustment device has a joint mechanism, two horizontal arms and two adjustment mechanisms. The joint mechanism forms a fixing hole configured to be disposed around the center column Each of the horizontal arms has a joint end and an adjustment end, the joint end is opposite to the adjustment end, and the joint end connects with the joint mechanism. One end of each of the adjustment mechanisms is mounted at the adjustment end of the horizontal arm, another end of each of the adjustment mechanisms is configured for being installed on one of the armrests.

What is claimed is: 
     
         1 . An armrests adjustment device for a chair, wherein the armrests adjustment device is assembled on a center column of a chair for being installed with two armrests, and the armrests adjustment device comprises:
 a joint mechanism having
 a fixing hole for being disposed around the center column; 
   two horizontal arms, each of the horizontal arms including
 a joint end connected to the joint mechanism; and 
 an adjustment end opposite to the joint end; and 
   two adjustment mechanisms, one end of each of the adjustment mechanisms mounted at the adjustment end of one of the horizontal arms, the other end of each of the adjustment mechanisms for being installed with one of the armrests.   
     
     
         2 . The armrests adjustment device as claimed in  claim 1 , wherein each of the adjustment mechanisms comprises:
 a first rod mounted at one of the adjustment ends; and   a second rod mounted at a top end of the first rod, an end of the second rod for being installed with the corresponding one of the armrests.   
     
     
         3 . The armrests adjustment device as claimed in  claim 2 , wherein each of the first rods is a first adjustment section, and the first adjustment section comprises:
 a first tube body mounted at the adjustment end of one of the horizontal arms;   a first column body rotatably and movably mounted in the first tube body;   an upward gear crown mounted at a top end of the first tube body;   a downward gear crown rotatably and movably mounted around the first column body, and selectively engaged with the upward gear crown;   a first fixing unit mounted on the first tube body for fixing a relative position and angle between the first tube body and the first column body; and   a second fixing unit mounted on the downward gear crown for fixing a relative position and angle between the first column body and the downward gear crown.   
     
     
         4 . The armrests adjustment device as claimed in  claim 2 , wherein each of the second rods is a second adjustment section, and the second adjustment section comprises:
 a second tube body mounted at the top end of the first rod;   a second column body movably mounted in the second tube body; and   a third fixing unit mounted on the second tube body for fixing a relative position between the second tube body and the second column body.   
     
     
         5 . The armrests adjustment device as claimed in  claim 4 , wherein
 the second column body includes
 a groove disposed on an outer surface of the second column body; and 
 a stopper mounted at one end of the groove; and 
   the second tube body includes
 a protruding rail mounted on an inner surface of the second tube body, movably engaging in the groove of the second column body, and selectively abutting against the stopper. 
   
     
     
         6 . The armrests adjustment device as claimed in  claim 2 , wherein each of the adjustment mechanisms further comprises
 a third adjustment section mounted at the end of the second rod and including
 a universal joint rotatably mounted with one of the armrests. 
   
     
     
         7 . The armrests adjustment device as claimed in  claim 6 , wherein the third adjustment section further includes
 a fourth fixing unit mounted on the universal joint for fixing a relative angle between the universal joint and the armrest.   
     
     
         8 . The armrests adjustment device as claimed in  claim 2 , wherein the first rod is nonparallel with the second rod. 
     
     
         9 . The armrests adjustment device as claimed in  claim 1 , wherein the joint mechanism comprises:
 a joint section;   a protrusion, wherein the fixing hole is formed from the protrusion and the joint section;   a gap formed between the protrusion and the joint section;   at least one through hole formed through the protrusion and disposed perpendicular to the gap;   at least one blind hole formed in the joint section and faced to the at least one through hole, and a number of the at least one blind hole equal to a number of the at least one through hole, each of the at least one blind hole including an internal thread; and   at least one joint screw mounted in the at least one through hole and screwed into the at least blind hole, a number of the at least one joint screw equal to the number of the at least one through hole.   
     
     
         10 . The armrests adjustment device as claimed in  claim 9 , wherein
 the joint section includes
 two joint blocks respectively mounted in the joint ends of the horizontal arms; 
   each of the joint ends includes
 a locking hole; 
   the joint mechanism includes
 two locking screws respectively mounted in the joint ends of the horizontal arms, respectively screwed with the joint blocks, and respectively abutting edges of the locking holes.