Adjustment mechanism for armrest

Abstract

An adjustment mechanism for armrests is revealed. An armrest includes an armrest surface and a lower plate fastened to form a space for receiving a movable block. Thus the movable block is moved forward and backward and positioned in relation to the lower plate. A rectangular slot is disposed on the movable block and a rectangular piece is moved and positioned transversely therein. A round slot is set on the rectangular piece while a hat-shaped disc is mounted in the round slot and fastened elastically on a projecting rod of a bottom frame. By a positioning bump on the hat-shaped disc elastically mounted into or separated from a positioning hole arranged circularly on the projecting rod, the hat-shaped disc and the bottom frame are rotated and positioned in relation to each other in a 360 degree circle. Thereby the armrest can be moved transversely and rotated 360 degrees.

What is claimed is: 
     
         1 . An adjustment mechanism for an armrest disposed on top of an armrest support comprising: an armrest surface, a lower plate, a bottom frame, a movable block, a rectangular piece, a hat-shaped disc, a plurality of positioning rings and a plurality of elastic parts corresponding to the positioning rings; wherein
 the armrest surface is fastened and integrated with the lower plate to form a rectangular inner space therebetween for receiving components related to armrest adjustment;   the lower plate is disposed with two symmetrical linear positioning slots each of which is formed by a plurality of curved slots and respectively set on the left and right sides of one end therein;   the movable block is movably mounted in the lower plate and having a length smaller than an internal length of the lower plate; the moveable block includes two symmetrical receiving slots respectively arranged at the left and right sides of one end thereof, a rectangular slot disposed around a middle part thereof, a transverse groove arranged at about a middle part in the rectangular slot, and a receiving groove mounted on one side of the rectangular slot; the receiving slot is for receive a positioning ring and an elastic member elastically pressing the positioning ring and is corresponding to the linear positioning slot of the lower plate so that the movable block is sliding forward and backward in relation to the lower plate and is positioned by the positioning ring elastically aligned with and against one of the curved slots of the linear positioning; the receiving groove is for receiving a positioning ring and an elastic member elastically pressing the positioning ring so that the positioning ring presses toward the rectangular slot;   the bottom frame is fixed on a top surface of the armrest support and having a projecting rod with a certain height arranged at a center thereof, a center hole disposed on a center of a top surface of the projecting rod and penetrating the projecting rod to be communicated with a groove on a bottom of the bottom frame, and a plurality of positioning holes arranged circularly at equal intervals on the top surface of the projecting rod;   the rectangular piece is movably mounted in the rectangular slot while a width of the rectangular piece is smaller than an internal width of the rectangular slot; the rectangular piece includes a plurality of curved slots arranged linearly on one side thereof and corresponding to the receiving groove of the movable block, a round slot set around a middle part thereof, and a center hole on a bottom surface of the round slot; while the rectangular piece is sliding transversely in the rectangular slot, the rectangular piece is positioned by the positioning ring in the receiving groove elastically aligned with and against one of the curved slots thereof;   the hat-shaped disc is mounted in the round slot of the rectangular piece and having a round slot on a bottom thereof that is corresponding to and assembled with the projecting rod of the bottom frame; an inner top surface of the slot is disposed with at least one positioning bump whose shape and the size are corresponding to the positioning hole on the top surface of the projecting rod;   a center hole mounted on the center of the hat-shaped disc is aligned with the center hole on the center of the projecting rod of the bottom frame; a fastener is passed through the center hole of the hat-shaped disc and the center hole of the bottom frame so that a rear end of the fastener is exposed inside the groove on the bottom of the bottom frame and an elastic part and a nut are set around and threaded onto the rear end of the fastener; thus the elastic part is elastically compressed between an inner bottom surface of the groove and the nut while the hat-shaped disc, the rectangular piece, the movable block, and the lower plate are fastened in turn from top to bottom to form a linking body that elastically presses against the projecting rod of the bottom frame; the positioning bump is elastically mounted into at least one of the positioning holes due to elasticity of the elastic part to be positioned; when the armrest surface and the linking body is lifted, the positioning bump is moved upward and released from the positioning hole by elasticity of the elastic part so that the armrest surface and the linking body are adjusted and rotated in a 360 degree circle;
 wherein the armrest surface and the lower plate are fastened to form the armrest; 
   wherein the lower plate slides forward and backward in relation to the movable block so as to achieve adjustment of the armrest in a fore-and-aft direction;   wherein the movable block slides transversely in relation to the rectangular piece so that the armrest is adjusted in a transverse direction;   wherein when the linking body formed by the hat-shaped disc, the rectangular piece, the movable block, and the lower plate is lifted, an angle of the armrest is adjusted in relation to the bottom frame in a 360 degree circle.   
     
     
         2 . The device as claimed in  claim 1 , wherein two symmetrical long flanges are disposed on the left and right sides in one end of the lower plate to form a sliding slot under each long flange; transverse edges of the movable block are respectively mounted into the sliding slots under each long flange and sliding therein. 
     
     
         3 . The device as claimed in  claim 1 , wherein a transverse guiding rail is arranged at one side in the rectangular slot and a guiding slot corresponding to the guiding rail is transversely disposed on one side of the rectangular piece;
 thus the guiding slot is assembled with the transverse guiding rail in the rectangular slot correspondingly.   
     
     
         4 . The device as claimed in  claim 1 , wherein the elastic part is a rubber ring with elasticity.