Abstract:
A folding chair is provided having a first front leg, a second front leg, a first rear leg, a second rear leg, a first link, a second link, a chair seat, and a backrest. The chair seat includes a seat member, a first support bracket, a second support bracket, and a cross-bar connecting the first and second support brackets. The first front leg, the first rear leg, the first link, and the first support bracket form a first four-bar linkage. The second front leg, the second rear leg, the second like, and the second support bracket form a second four-bar linkage.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority to and benefit of Chinese Patent Application No. 02270728.X, filed Nov. 7, 2002, and entitled “A Type of Folding Chair,” which application is incorporated herein by reference in its entirety. 
   BACKGROUND OF THE INVENTION 
   1. The Field of the Invention 
   The present invention is directed to folding chairs. 
   2. The Relevant Technology 
   Increasingly high functional requirements are being placed on modem furniture, whether for home or office, in order to make them more practical, comfortable, and convenient.  FIG. 5  illustrates a conventional folding chair, illustrating features typical of folding chairs in the industry. The folding chair includes a first leg assembly  1 , a second leg assembly  2 , a first link  3 , a second link  4 , a chair seat  5 , a support bracket  6 , a backrest  7 , a right cross-bar  8 , and a left cross-bar  9 . 
   The first leg assembly  1  comprises a right front leg  11  and a right rear leg  12 . Similarly, the second leg assembly  2  comprises a left front leg  21  and a left rear leg  22 . The right front leg  11 , the right rear leg  12 , the first link  3 , and the chair seat  5 , form a first four-bar linkage and the left front leg  21 , the left rear leg  22 , the second link  4 , and the chair seat  5 , form a second four-bar linkage. During use, the folding chair folds fully. 
   A first projecting bar  10  and second projecting bar  20  extend outwardly from the right and left side of the support bracket  6 . The first link  3  and the second link  4  rest on the first projecting bar  10  and second projecting bar  20  of the Support bracket  6  when the chair is in the use position. Thus, repeated use of the folding chair tends to damage the links  3  and  4 , thereby lowering the service life of the folding chair and increasing the difficulty of manufacture. 
   The chair seat  5  and the support bracket  6  form the seat assembly. The chair seat  5  is set over the support bracket  6 . As a result, not only is the seat assembly insufficiently strong, but also the weight of the folding chair is increased. In addition, the top surface of the chair seat  5  and front surface of the backrest  7  are substantially flat. Thus, the user&#39;s weight cannot be evenly distributed on the chair seat. Stress tends to concentrate, damaging the chair seat  5  and backrest  7  and thereby reducing the service life of the folding chair. 
   SUMMARY OF THE INVENTION 
   The present invention seeks to address the disadvantages found in the prior art by providing a folding chair which is high-strength, comfortable, and of simple manufacturing design, thus reducing the cost of the folding chair while providing the strength necessary to support a person thereon. 
   In one aspect of the invention, a folding chair is provided having a first front leg; a first rear leg; a first link pivotally connected to the first front leg and the first rear leg; a first support bracket pivotally connected to the first front leg and the first rear leg, the first front leg, first rear leg, first link and first support bracket forming a four-bar, four pivot linkage that allows the folding chair to be moved between a use position and a storage position, wherein the first support bracket comprises a lateral portion and a bottom portion. 
   The folding chair may also have a second front leg; a second rear leg; a second link pivotally connected to the second front leg and the second rear leg; a second support bracket pivotally connected to the second front leg and the second rear leg, the second front leg, the second rear leg, the second link and the second support bracket forming a four-bar, four-pivot linkage that allows the folding chair to be moved between a use position and a storage position, wherein the second support bracket comprises a lateral portion and a bottom portion. 
   The chair may also have a blow molded seat member connected to the first support bracket and the second support bracket, the blow molded seat member including an upper surface and a lower surface generally spaced apart from the upper surface and extending between a first edge and a second edge, wherein a first attachment recess and second attachment recess are formed on the seat member, the first attachment recess comprising a lateral portion formed on the first edge and a bottom portion formed on the lower surface of the seat member, the second attachment recess comprising a lateral portion formed on the second edge and a bottom portion formed on the lower surface of the seat member, wherein the lateral portion of the first support bracket is fixedly secured to the lateral portion of the first attachment recess, and the bottom portion of the first support bracket is fixedly secured to the bottom portion of the first attachment recess, and wherein the lateral portion of the second support bracket is fixedly secured to the lateral portion of the second attachment recess, and the bottom portion of the second support bracket is fixedly secured to the bottom portion of the second attachment recess. 
   The upper surface of the seat member may have a slightly curved surface. The lower surface of the seat member may have a plurality of grooves. 
   A cross-bar may be disposed transversely to the first support member and the second support member and coupled therebetween. 
   The first attachment recess and second attachment recess may further include slots formed at opposing ends of the bottom portion extending inwardly from the lower surface of the seat member. Additionally, the first support member and the second support member may include flanges disposed at opposing ends of the bottom portion, wherein the flanges are configured to be disposed in the slots of the first attachment recess and second attachment recess. 
   The first front leg and the second front leg may be connected by a front support bar, in one embodiment, forming a substantially U-shaped structure. Similarly, the first rear leg and the second rear leg are connected by a rear support bar, in one embodiment, forming a substantially U-shaped structure. 
   The folding chair may also include a blown-molded backrest having a front surface and a rear surface generally spaced apart from the front surface, the backrest being configured to be connect to both an upper portion of the first front leg and an upper portion of the second front leg. The back rest may include apertures formed on a bottom surface thereof so that the back rest can form a press-fit connection with the upper portions of the first front leg and the second front leg. The front surface of the back rest may have a slightly curved surface. 
   These and other advantages and features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     To further clarify the above and other advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which: 
       FIG. 1  illustrates a perspective view of a folding chair according to one embodiment of the present invention. 
       FIG. 2  is an exploded view of the folding chair of  FIG. 1 , illustrated in an unfolded or functional position. 
       FIG. 3  is a perspective view of the folding chair of  FIG. 1 , viewing the chair from the underside position. 
       FIG. 4  is a perspective view of the folding chair of  FIG. 1 , illustrated in a folded position. 
       FIG. 5  is a conventional folding chair. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 through 4  illustrate an exemplary folding chair incorporating features of the present invention. First, with reference to  FIG. 1 , the folding chair includes a front support frame  1 , a rear support frame  2 , a first link  31 , and second link  32 , a chair seat  4 , and a backrest  5 . The folding chair is selectively positionable between a functional or unfolded position ( FIG. 1 ) and a storage or folded position ( FIG. 4 ). The chair seat  4  comprises a seat member  41 , a first support bracket  42 , and a second support bracket  43 . 
   The front support frame  1  comprises a right front leg  11  and a left front leg  21 . A front base bar  13  joins the right front leg  11  and the left front leg  21 . As such, the right front leg  11 , left front leg  21  and front base bar  13  form a substantially U-shaped member. The front base bar  13  is curved, and there are two bases  555  located thereon. However, the front base bar  13  can be disposed at any location along the length of right front leg  11  and left front leg  21  below the chair seat  4  to provide strength therebetween. Likewise, the rear support frame  2  comprises a right rear leg  12  and left rear leg  22 . A rear base bar  23  joins the right rear leg  12  and the left rear leg  22 . As such, the right rear leg  12 , left rear leg  22 , and rear base bar  23  forms a substantially U-shaped member. The rear base bar  23  is curved, and there are two bases  556  located thereon. However, the rear base bar  23  can be disposed at any location along the length of right rear leg  12  and left rear leg  22  below the chair seat  4  to provide strength therebetween. 
   The front support frame  1  and the rear support frame  2  are preferably hollow structures. This type of structure, in addition to reducing the weight of the folding chair, increases its rigidity and resistance to bending. 
   With reference now to  FIG. 2 , the right front leg  11  has a first upper terminal point  111 . There are two holes,  112  and  113 , exposed outwardly in the mid-section thereof. Hole  112  is the location where the first link  31  and the right front leg  11  are pivotally coupled by means of a rivet  311 . Hole  113  is the location where the first support bracket  42  and the right front leg  11  are pivotally coupled by means of a rivet  312 . The left front leg  21  has a second terminal point  121 . There are two holes,  122  and  123 , exposed outwardly in the mid-section thereof. Hole  122  is the location where the second link  32  and the left front leg  21  are pivotally coupled by means of a rivet  321 . Hole  123  is the location where the second support bracket  43  and the left front leg  21  are pivotally coupled by means of a rivet  322 . 
   The right rear leg  12  extends upwardly, where there is a third terminal point  26 . A first end cap  28  is disposed at the top end of the right rear leg  12 . There are two holes  212  and  213  exposed outwardly and formed at an end thereof. Hole  212  is the location where the first link  31  and the right rear leg  12  are pivotally coupled by means of a rivet  331 . Hole  213  is the location where the first support bracket  42  and the right rear leg  12  are pivotally coupled by means of a rivet  332 . 
   The left rear leg  22  extends upwardly, where there is a fourth terminal point  27 . A second end cap  29  is disposed at the top end of the left rear leg  22 . There are two holes  222  and  223  exposed outwardly and formed at an end thereat. Hole  222  is the location where the second link  32  and the left rear leg  22  are pivotally coupled by means of a rivet  341 . Hole  223  is the location where the second support bracket  43  and the left rear leg  22  are pivotally coupled by means of a rivet  342 . 
   The first link  31  is pivotally connected to the right front leg  11  and the right rear leg  12  at holes  112  and  212 , respectively. The first support bracket  43  is pivotally connected to the right front leg  11  and the right rear leg  12  at holes  113  and  213 . respectively. The pivot connections at holes  112 ,  212 ,  113  and  213 , thus form a foldable four-bar linkage. When the chair is in the use or unfolded position, the outer side  14  of the central part of the right front leg  11  rests on the upper end  24  of the first end cap  28  of the right rear leg  12 . 
   Likewise, the second link  32  is pivotally connected to the left front leg  21  and the left rear leg  22  at holes  122  and  222 , respectively. Further, the second support bracket  43  is pivotally connected to the left front leg  21  and the left rear leg  22  at holes  123  and  223 , respectively. The pivot connection at holes  122 ,  222 ,  123  and  223  thus form a foldable four-bar linkage. When the chair is in the use or unfolded position, the outer side  15  of the central part of the left front leg  21  rests on the upper end  25  of the second end cap  29  of the left rear leg  22 . 
   Washers  61 ,  62 ,  63  and  64  are disposed between chair seat  4  and front support frame  1  and the rear support frame  2 . The washers restrict movement in the left and right directions of the chair seat  4  relative to the front support frame  1  and rear support frame  2 . In addition, they facilitate rotation of the chair seat  4  relative to the front support frame  1 . 
     FIG. 3  shows a perspective view of the chair viewing the chair from underneath the chair seat  4 . The chair seat  4  comprises a light-weight seat member  41 , a first support bracket  42 , a second support bracket  43 , and a cross-bar  44 . The chair seat  4  is positioned between the right front and rear legs  11 ,  12  and the left front and rear legs  21 ,  22 . 
   In one embodiment, the seat member  41  is a blow-molded, hollow, plastic structure. The seat member  41  includes an upper surface and a lower surface  45 . The outer contour of the upper surface of the seat member  41  is preferably curved. In addition, the upper surface is slightly concave towards the center of the seat member  41 . Thus, it provides a comfortable seating surface. In addition, the lower surface  45  of the seat member  41  has four grooves  46  and many recesses  47  that are slightly concave towards the center of the seat member  41 . The grooves  46  and recesses  47  can increase the resistance of the seat member  41  to bending and evenly distribute the weight of the user when sitting thereon. In addition, the grooves  46  enable the user to grasp the chair seat  4  easily when folding. 
   On the lower surface  45  of the seat member  41 , a first attachment recess  411  and second attachment recess  412  are formed on the right and left side, respectively. In addition, at each end of the ridges  411 ,  412 , are formed slots  413 ,  414 ,  415  and  416  which extend into the seat member  41 . The first support bracket  42  and second support bracket  43  is disposed in the first attachment recess  411  and second attachment recess  412 , respectively. 
   As shown in  FIG. 2 , the first support bracket  42  is L-shaped. Support bracket  42  includes a first lateral side  421 , a first bottom side  422 , a first flange  423 , and a second flange  427 . When disposed in the first attachment recess  411  of the seat member  41 , the first flange  423  and the second flange  427  are inserted into the first slot  413  and the second slot  415 . The first lateral side  421  and the first bottom side  422  are then secured to the first attachment recess  411  using rivets  425 . 
   Similarly, the second support bracket  43  is L-shaped. The second support bracket  43  includes a second lateral side  431 , a second bottom side  432 , a third flange  433 , and a fourth flange  437 . When disposed in the second attachment recess  412  of the seat member  41 , the two second flanges  433  and  437  are inserted into the third slot  414  and the fourth slot  416 , respectively. The second lateral side  431  and the second bottom side  432  are then secured to the second attachment recess  412  using rivets  435 . The first support bracket  42  and the second support bracket  43  fix the movement relative to the seat member  41  and evenly distribute the weight of the user on the seat member while also reducing the weight of the folding chair. 
   A cross-bar  44  passes through the seat member  41 , providing a connection between the first support bracket  42  and the second support bracket  43  and thus creates an H-shape support structure. The cross-bar  44  fixes the movement of the seat member  41  relative to the first support bracket  42  and the second support bracket  43 . The use of the cross-bar  44  strengthens the seat member  41 , causing the stress in chair seat  4  to be distributed and reducing the tendency of breakage or weakening at the connections between the front support frame  1 , the rear support frame  2 , the first support bracket  42 , and the second support bracket  43 . Thus, it extends the service life of the folding chair. 
   In one embodiment, the backrest  5  is a hollow, blow-molded plastic structure. Preferably, the backrest  5  is curved, concave toward the front of the chair, providing a comfortable structure for users to rest against. The backrest  5  is positioned on the first upper terminal point  111  of the right front leg  11  and the second upper terminal point  121  of the left front leg  21 . The backrest  5  contains apertures at the ends of a bottom surface, which apertures are configured to receive the ends  111 ,  121  of right front leg  11  and left front leg  21 . Preferably, the backrest  5  can be press-fit onto the front support frame  1 . In addition, the backrest  5  can be secured thereto with two rivets  51 . 
   The chair is selectively foldable between a use position ( FIG. 1 ) and a storage position ( FIG. 4 ). When folded, the front support frame  1  and the rear support frame  2  are parallel to each other. The seat  4  is also substantially parallel to the back rest  5 . This folding structure is easy to fold, extremely compact, and does not cause undue stress on the connections between the front support frame  1 , the rear support frame  2 , and the chair seat  4 . 
   The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.