Patent Publication Number: US-8979199-B2

Title: Chair with pre-stressing structure

Description:
CROSS-REFERENCE TO RELATED U.S. APPLICATIONS 
     The present application is a continuation-in-part of U.S. patent application Ser. No. 12/509,461 filed on Jul. 25, 2009, now abandoned and entitled “Chair with Pre-stressing Structure.” 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not applicable. 
     REFERENCE TO AN APPENDIX SUBMITTED ON COMPACT DISC 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a chair, and more particularly to an innovative one which is designed with a pre-pressing structure. 
     2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98 
     At present, there are various types of chairs that are functionally designed to meet ergonomic requirements for improved comfort. Since the seat cushion and back of common chairs are assembled securely, the chair back becomes a fixed part. In such a case, the users have to take a fixed sitting posture, leading to discomfort when sitting for a longer time. To overcome the aforementioned problems, a chair with an elastic structure has recently been developed, i.e.: an elastic structure is set at the assembly portion of the cushion and back of chair, so that the back of chair can be tilted back and rebounded via the elastic structure. 
     However, some shortcomings of the structural design of said chair with elastic structure are still observed, wherein the elastic structural design is a crucial influential factor. Elastic fatigue cannot be resisted in a conventional structural design, leading to shorter service life of the chair. Thus, it would be an advancement in the art to provide an improved device that can be advantageous to users. 
     Moreover, a chair with an elastic structure at the joint has been developed in prior art, as illustrated by U.S. Pat. No. 6,682,252, wherein a torsion tube is assembled at the preset joint of the chair, and then a set of bolts and nut positioning members are meshed with the tooth, so that the joint and torsion tube could be assembled together in a limited condition. Meanwhile, when the joint generates pivotal motion, the torque tube will be twisted to accumulate resetting elasticity. Yet, it is found in practical applications that owing to numerous components, the installers must consider the relationship among so many components such as: some parts corresponding to the joint, torsion tube and bolt and nut positioning members. And they may be assembled using other special toolkits. Hence, some problems and shortcomings, e.g.: difficult and time-consuming assembly and higher manufacturing cost, need to be overcome. 
     Thus, to overcome the aforementioned problems of the prior art, it would be an advancement if the art to provide an improved structure that can significantly improve the efficacy. 
     Therefore, the inventor has provided the present invention of practicability after deliberate experimentation and evaluation based on years of experience in the production, development and design of related products. 
     BRIEF SUMMARY OF THE INVENTION 
     Based on above-specified structural design, the present invention is operated as follows: 
     The core aspect disclosed in the present invention mainly lies in the assembled pattern of the pre-pressing structure  20 . According to the assembly steps shown in  FIGS. 4 ,  5  and  6 , firstly the pre-pressing member  22  and the pivoting seat  23  are assembled. When the pre-pressing member  22  is intended to be set into the pivoting seat  23 , the embedded section  224  on the end of the multi-segment directional lug  223  will be firstly embedded into the multi-segment directional groove  233  for the purpose of orientation (as shown in  FIG. 6 ). However, the embedding angle between the positioning convex part  31  and the calking groove  32  is not yet aligned due to the design of the pre-pressing angle (X), so embedding cannot be realized. Then, referring to  FIGS. 7 ,  8  and  9 , an external force (indicated by arrow L 1  in  FIG. 7 ) shall be applied to the limiting seat  221 , making it swing to an angle for complete alignment of the positioning convex part  31  and embedding into (indicated by arrow L 2  in  FIG. 7 ) the calking groove  32  for a positioning state. When the limiting seat  221  is swung, the multi-segment directional lug  223  is embedded so that the cyclic elastic member  222  is twisted to accumulate elasticity (due to reverse stress for its inside and outside), so as to achieve elastic pre-pressing effect. When the bearing seat  11  (back or seat cushion) of the chair  10  swings elastically (indicated by arrow L 3  in  FIG. 11 ), this could provide better elasticity and longer service life. 
     Referring also to  FIG. 10 , the other side of the pre-pressing member  22  is assembled into the holding space  210  of pre-pressing member&#39;s fixed seat  21 , then the assembly of pre-pressing structure  20  has been completed. Furthermore, the assembly status of the pre-pressing structure  20  could be fixed by the screwing of the bolt  41  and nut  42 , so as to mate with the corresponding components of the chair. However, said bolt  41  and nut  42  are not an integral part for the pre-pressing structure  20 , but positioning members previously set on the chair&#39;s joint. According to the description mentioned above, the pre-pressing structure  20  comprises of fairly simple components. There are only three separate components required to be assembled, of which the pre-pressing member&#39;s fixed seat  21  is directly installed on the bearing seat  11  of the chair body  10 . The pivoting seat  23  is directly inserted into the supporting member  12  of chair body  10 . Another independent component is pre-pressing member  22 ; the elastic pre-pressing effect is formed in a way that when the embedded section  224  located on the end of the multi-segment directional lug  223  is firstly embedded into the multi-segment directional groove  233 , a force is further applied to the limiting seat  221 , making it swing to an angle for the embedding of the positioning convex part  31  into the calking groove  32  for elastic pre-pressing effect. Hence, the assembly process of the pre-pressing structure  20  is quite simple without any components&#39; complex mating relation, and there is also no need of other tools for the benefit of ordinary people. 
     The pre-pressing structure of the present invention could be installed on the back of chair. In the embodiments, when a user leans on the back of chair, the positioning convex part  31  of the positioning member  30  will swing along with the varying inclination angle of the back of chair, and the cyclic elastic member  222  is twisted to accumulate elasticity. When the user&#39;s back leaves the back of chair, the positioning convex part  31  will drive the back of chair to be reset via the elastic resetting force of the cyclic elastic member  222 , making the user feel comfortable. Of which, said calking groove  32  is wider than the positioning convex part  31 , so there is a displacement space for said positioning convex part  31  in the calking groove  32 , and the maximum inclination angle of the back of chair could be limited (indicated by arrow L 3  in  FIG. 11 ). 
     Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is an assembled perspective view of the present invention wherein the pre-pressing structure is applied to a chair. 
         FIG. 2  is an exploded perspective view of the pre-pressing structure of the present invention. 
         FIG. 3  is an exploded sectional view of the pre-pressing structure of the present invention. 
         FIG. 4  is a perspective view of assembly step  1  of the pre-pressing structure of the present invention. 
         FIG. 5  is a plan view of assembly step  1  of the pre-pressing structure of the present invention. 
         FIG. 6  is a sectional view of assembly step  1  of the pre-pressing structure of the present invention. 
         FIG. 7  is a perspective view of assembly step  2  of the pre-pressing structure of the present invention. 
         FIG. 8  is a plan view of assembly step  2  of the pre-pressing structure of the present invention. 
         FIG. 9  is a sectional view of assembly step  2  of the pre-pressing structure of the present invention. 
         FIG. 10  is an assembled sectional view of the pre-pressing structure of the present invention. 
         FIG. 11  is a plan side view of the present invention wherein the pre-pressing structure allows the bearing seat of chair to swing elastically. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 ,  2 ,  3  and  10  depict the preferred embodiments of the chair with pre-pressing structure, which, however, are provided for only explanatory objective for patent claims; said chair comprising:
         a chair body  10 , comprising of at least a bearing seat  11  fitted with a mounting surface  111  and a supporting member  12 ;   at least a pre-pressing structure  20 , enabling the chair body  10  to be provided with elastic restoring force; the pre-pressing structure  20  comprising:   at least a pre-pressing member&#39;s fixed seat  21 , which is located on the mounting surface  111  of the bearing seat  11  and provided with a holding space  210 ;   at least a pre-pressing member  22 , which is assembled in the holding space  210  of the pre-pressing member&#39;s fixed seat  21 ; the pre-pressing member  22  comprises of a limiting seat  221 , a cyclic elastic member  222  and a multi-segment directional lug  223  protruded at one side of the center of said cyclic elastic member  222 ;   an embedded section  224 , which is formed on the end of the multi-segment directional lug  223 ;   a pivoting seat  23 , which is provided with a multi-segment directional groove  233  to be mated with the multi-segment directional lug  223 . A grooved portion  234  is formed externally onto the multi-segment directional groove  233 . The pivoting seat  23  is also provided with an inserting part  235  for inserting into the supporting member  12  of the chair body  10 ;   a pre-pressing positioning member  30 , which is composed of at least a positioning convex part  31  set on the limiting seat  221  and at least a calking groove  32  of the grooved portion  234  set on the pivoting seat  23 ; of which, the calking groove  32  is wider than the positioning convex part  31 , so that there is a displacement space for said positioning convex part  31  in the calking groove  32 ;   a pre-pressing angle (X), which permits the embedding angle between the multi-segment directional groove  233  and multi-segment directional lug  223  to vary from that between the positioning convex part  31  and the calking groove  32 , as shown in  FIG. 8 .       

     With the setting of the pre-pressing angle (X), when the pre-pressing member  22  and the pivoting seat  23  are assembled, the embedded section  224  located on the end of multi-segment directional lug  223  will be embedded into the multi-segment directional groove  233  for the purpose of orientation. As the embedding angle between the positioning convex part  31  and the calking groove  32  is not yet aligned, an external force shall be applied to the limiting seat  221 , making it swing to an angle for embedding. When the limiting seat  221  is swung, the multi-segment directional lug  223  is embedded so that the cyclic elastic member  222  is twisted (note: due to reverse stress for its inside and outside) to accumulate elasticity, realizing elastic pre-pressing effect. 
     Of which, the bearing seat  11  could be applied to either the back or seat cushion of the chair  10 . The figures illustrated in the present invention depict the embodiment applied onto the back of chair. 
     Of which, the multi-segment directional lug  223  and the multi-segment directional groove  233  could be of either cross-shaped (shown in  FIG. 2 ) or polygonal pattern.