Patent Publication Number: US-8991928-B2

Title: Constricting member of chair footrest ring

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a constricting structure of a chair footrest ring, especially to a constricting member of a chair footrest ring that having simple structure so that not only manufacturing cost is reduced and assembling of the device is also more convenient and faster. The constricting member of a chair footrest ring is of higher practical value. 
     2. Description of Related Art 
     No matter at home or in the office, chairs are essentials for our daily lives. For user&#39;s comfort after sitting in chairs for a long term, arc-shaped chair seats and backrests are designed according to ergonomics. Thus users will not have pain or discomfort after long term use. Moreover, high chairs are disposed with a footrest ring around a central tube thereof for users&#39; feet to rest thereon comfortably. 
     Refer to U.S. Pat. No. 7,387,343 “Constricting device for the footrest ring of a chair” granted and published on Jun. 17, 2008, a footrest ring is arranged around a central tube of a chair. A sleeve for mounting the footrest ring on the central tube is taper-shaped and a constricting assembly set between the central tube of the chair and the taper-shaped sleeve of the footrest ring. The constricting assembly includes a main constricting body and a fixing ring which allows the main constricting body and the sleeve of the footrest ring to be fixed and connected with each other. Besides, the main constricting body is taper-shaped corresponding to the taper-shaped sleeve of the footrest ring for connecting with. A hole is disposed on the central part of the main constricting body to allow the central tube of the chair passing through. And the main constricting body is mounted with at least one trench thereon. 
     Although the above constricting device for a footrest ring of a chair can fix the footrest ring on the central tube of the chair firmly, the design of the constricting assembly including a main constricting body and a fixing ring and used for connecting and positioning the sleeve of the footrest ring makes the structure more complicated. Thus the manufacturing cost is high and the assembly is inconvenient and time-consuming. 
     There is room for improvement and a need to provide a novel design of a constricting device for a footrest ring of a chair. 
     SUMMARY OF THE INVENTION 
     Therefore it is a primary object of the present invention to provide a constricting member of a chair footrest ring in which a constricting sleeve is formed integrally and is used to connect and position a footrest ring in a chair. The structure is simpler and the assembly is more convenient. Thus the manufacturing cost is reduced effectively and the assembly is faster and more convenient. The constricting device of a chair footrest ring is of higher practical value. 
     In order to achieve the above objet, a constricting member of a chair footrest ring is mainly a constricting sleeve with a hole mounted on a center thereof. A plurality of tapered-shaped mounting and fixing parts is disposed projectingly on an outer surface of the constricting sleeve, from top to bottom and expanded outward. A positioning projective ring is projecting from and integrally formed on an outer edge on a top end of the constricting sleeve. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein 
         FIG. 1  is a perspective view of an embodiment according to the present invention; 
         FIG. 2  is a front view of a cross section of an embodiment according to the present invention; 
         FIG. 3  is a top view of a cross section of an embodiment according to the present invention; 
         FIG. 4  is a side view of an embodiment in use according to the present invention; and 
         FIG. 5  is a schematic drawing showing a partial cross sectional view of an embodiment in use according to the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Refer to  FIG. 1 ,  FIG. 2 , and  FIG. 3 , a constricting member for a chair footrest ring is a constricting sleeve  1  and a hole  11  is mounted on a center of the constricting sleeve  1 . A plurality of tapered-shaped mounting and fixing parts  12  is disposed projectingly on an outer surface of the constricting sleeve  1 , from top to bottom and expanded outward. At least one trench  13  is also formed on the outer surface of the constricting sleeve  1 . A positioning projective ring  14  is projecting from and integrally formed on an outer edge on a top end of the constricting sleeve  1 . 
     While in use, refer to  FIG. 4  and  FIG. 5 , a central tube  21  of a chair  2  is passed through the hole  11  on the center of the constricting sleeve  1  and a taper-shaped sleeve  31  on a center of a footrest ring  3  is aligned with the constricting sleeve  1  and then is pushed and pressed from top to bottom to be assembled with the constricting sleeve  1 . Due to the tapered-shaped of the sleeve  31  of the footrest ring  3 , the sleeve  31  is able to pass through the positioning projective ring  14  on top of the constricting sleeve  1  by a certain push-press force. After being moved downward to be sleeved with the mounting and fixing parts  12  around the constricting sleeve  1 , the sleeve  31  and the mounting and fixing parts  12  are connected to, mounted and positioned by each other tightly. At the same time, the top end of the sleeve  31  is limited and positioned by the positioning projective ring  14 . Thus the footrest ring  3  will not move upward and get loose. Moreover, the mounting and fixing parts  12  of the constricting sleeve  1  can be pressed and constricted more strongly to the central tube  21  of the chair  2  by means of contraction allowance at the trench  13  while being pressed inward by the sleeve  31 . Along with a larger force a user applied to the footrest ring  3 , the constricting sleeve  1  in the sleeve  31  of the footrest ring  3  is pressed and constricted more severely. Thus the central tube  21  of the chair  2  is pressed and positioned more appropriately by the constricting sleeve  1 . Therefore the footrest ring  3  is fixed around the central tube  21  of the chair  2  firmly, not easy to fall off. 
     In summary, the present invention features on the integrally-formed constricting sleeve compared with conventional structure. The footrest ring is connected to and positioned around the central tube of the chair by the constricting sleeve. The whole structure of the present invention is simpler so that not only the manufacturing cost is reduced significantly and the assembly operation is more convenient and faster. The constricting member is of higher practical value. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative devices shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalent.