Patent Publication Number: US-9835191-B1

Title: Chair footrest ring positioning structure

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a chair footrest ring positioning structure characterized in that a guide region tilts downward and is concavely disposed on the outer surface of any one side of the lower segment of the tightening case, and on which anti-slip pads are fixed therein and grooves are concavely disposed peripherally thereon. Thus, bumps extending from the inner side of the sleeve corresponding in shape to the middle of the footrest ring and fitted around the tightening case are inserted into the grooves of the tightening case, and the middle pipe of the chair is rotated to move the tightening case by a predetermined distance and thereby causing the guide region to undergo a displacement to drive the insertion of the bumps, to effectuate dynamic adjustment and thus achieve a predetermined degree of tightness. 
     2. Description of the Prior Art 
     A conventional footrest ring coupled to a tall chair and positioned at a predetermined height is characterized in that a tightening component of appropriate tightness is disposed at a predetermined segment of a middle pipe of the chair. Thus, the tightening component allows a sleeve to be held in the middle of the footrest ring, and the middle of the footrest ring is of a predetermined width. Hence, the footrest ring is confined to the predetermined segment of the middle pipe and thus is convenient to place a foot on. 
     Although the footrest ring in operation is tightened, it is predisposed to tightness inadequacy after long use. 
     In view of the aforesaid drawback of the prior art, the present invention provides a chair footrest ring positioning structure characterized in that a guide region tilts downward and is concavely disposed on the outer surface of any one side of the lower segment of the tightening case, and on which anti-slip pads are fixed therein and grooves are concavely disposed peripherally thereon. Thus, bumps extending from the inner side of the sleeve corresponding in shape to the middle of the footrest ring and fitted around the tightening case are inserted into the grooves of the tightening case, and the middle pipe of the chair is rotated to move the tightening case by a predetermined distance and thereby causing the guide region to undergo a displacement to drive the insertion of the bumps, to effectuate dynamic adjustment and thus achieve a predetermined degree of tightness. 
     SUMMARY OF THE INVENTION 
     Considering that a conventional footrest ring coupled to a predetermined segment of a chair is predisposed to tightness inadequacy because of a small outer diameter of a middle pipe of the chair, the present invention aims to improve the conventional footrest ring so that a guide region tilting downward is concavely disposed on the outer surface of any one side of the lower segment of the tightening case, and on which one or more anti-slip pads are fixed therein and one or more grooves are concavely disposed peripherally thereon. Thus, one or more bumps extending from the inner side of the sleeve corresponding in shape to the middle of the footrest ring and fitted around the tightening case are inserted into the grooves of the tightening case, and the middle pipe of the chair is rotated to move the tightening case by a predetermined distance and thereby causing the guide region to undergo a displacement to drive the insertion of the bumps, thereby pushing the tightening case inward to effectuate dynamic adjustment and thus achieve a predetermined degree of tightness. 
     It is an objective of the present invention to provide a footrest ring coupled to a predetermined segment of a middle pipe of a chair, characterized in that a chair footrest ring positioning structure is subjected to a position limitation with enhanced tightening. The footrest ring positioning structure comprises a tightening case, at least one anti-slip pad, and a footrest ring. One or more grooves are concavely disposed on the periphery of the tightening case and correspond in position to one or more grooves concavely disposed on each anti-slip pad fixed inside an internal space of the tightening case, respectively. The advantageous technical features of the chair footrest ring positioning structure are as follows: a guide region tilting downward is concavely disposed on the outer surface of any one side of the lower segment of the tightening case, and on which one or more anti-slip pads are fixed therein and one or more grooves are concavely disposed peripherally thereon, to guide the insertion of the middle pipe of the chair; a sleeve corresponding in shape to the middle of the footrest ring is fitted around the tightening case; and one or more bumps extending from the inner side of the sleeve are inserted into the grooves of the tightening case. When the middle pipe of the chair is rotated to move the tightening case by a predetermined distance, the guide region undergoes a displacement to drive the insertion of the bumps, thereby pushing the tightening case inward to effectuate dynamic adjustment and thus achieve a predetermined degree of tightness. 
     Another objective of the present invention is that a guide region tilting downward is concavely disposed on the lower segment of the tightening case and positioned proximate to each groove, and the depth reached by the guide region decreases along the groove. Hence, the middle pipe of the chair is rotated by a larger angle to move the tightening case by a longer distance and thereby drives the insertion of the bumps extending from the inner side of the sleeve, thereby pushing the tightening case inward harder to achieve a higher degree of tightness. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a tightening case of the present invention; 
         FIG. 2  is an exploded view of the tightening case and related components of the present invention; 
         FIG. 3  is a perspective view of the tightening case and related components put together according to the present invention; 
         FIG. 4  is a rear perspective view of the tightening case and related components put together according to the present invention; 
         FIG. 5  is a front view of the tightening case inserted into a sleeve corresponding in shape to the middle of a footrest ring according to the present invention; 
         FIG. 6  is a top cross-sectional view of the tightening case inserted into a sleeve corresponding in shape to the middle of the footrest ring according to the present invention; 
         FIG. 7  is a schematic view of how a middle pipe of the chair is rotated to move the tightening case according to the present invention; and 
         FIG. 8  is a top cross-sectional view of how a middle pipe of the chair is rotated to move the tightening case according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT OF THE INVENTION 
     The present invention provides a chair footrest ring positioning structure as shown in  FIG. 2  and  FIG. 5 . According to the present invention, a footrest ring  3  is coupled to a predetermined segment of a middle pipe  4  of a chair. To impose a position limitation with enhanced tightening upon the chair footrest ring positioning structure, the chair footrest ring positioning structure comprises a tightening case  1 , at least an anti-slip pad  2 , and a footrest ring  3 . One or more grooves  11  are concavely disposed on the periphery of the tightening case  1  and correspond in position to one or more grooves  21  concavely disposed on each anti-slip pad  2  fixed inside an internal space  12  of the tightening case  1 , respectively, as shown in  FIG. 3  and  FIG. 4 . One or more holes  13  are disposed between two grooves  11  of the tightening case  1  to a predetermined extent, so that bumps  22  extending from related parts of the anti-slip pads  2  fixed inside the internal space  12  of the tightening case  1  are inserted into the holes  13 , respectively. The aforesaid components and arrangement thereof are attributed to the prior art and thus are not regarded as claimed technical features of the present invention. 
     The distinguishing technical features of the present invention, which distinguish the present invention from the prior art, are described below. A guide region  14  tilting downward is concavely disposed on the outer surface of any one side of the lower segment of the tightening case  1 . One or more anti-slip pads  2  are fixed inside the internal space  12  of the tightening case  1 , and one or more grooves  11  are concavely disposed at a periphery of the tightening case  1  (as shown in  FIG. 1 ,  FIG. 2 ), to facilitate the insertion of the middle pipe  4  of the chair (as shown in  FIG. 5 ). A sleeve  31  corresponding in shape to the middle of the footrest ring  3  is fitted around the tightening case  1 . One or more bumps  32  extending from the inner side of the sleeve  31  are inserted into the grooves  11 ,  21  of the tightening case  1  (as shown in  FIG. 6 ), respectively. When the middle pipe  4  of the chair is rotated to move the tightening case  1  by a predetermined distance (as shown in  FIG. 7 ), the guide region  14  undergoes a displacement to drive the insertion of the bumps  32  (as shown in  FIG. 8 ), thereby pushing the tightening case  1  inward to effectuate dynamic adjustment and thus achieve a predetermined degree of tightness.