Patent Publication Number: US-6902231-B1

Title: Collapsible chair

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a collapsible chair, more particularly to a collapsible chair with a compact folded configuration and that is able to be reclined to varying degrees and in such a manner that a backrest frame and a legrest frame are simultaneously adjusted in a single-step operation. 
   2. Description of the Related Art 
   U.S. Pat. No. 5,570,926 discloses an easychair including a frame forming the back of the chair, two side members forming the seat, and armrests that are spaced apart. The side members and the armrests are connected to the frame. A U-shaped frame serves as a legrest, and the base of the chair is formed using a front leg unit and a rear leg unit. Each armrest includes a slide rod, and ends of the front leg unit are slidably mounted to the slide rod via a forked yoke and an eccentric, which serve as a locking mechanism. 
   One drawback of the aforesaid easychair is that the locking mechanism is inconvenient to operate. In addition, the locking mechanism tends to wear out over time since friction is used to realize the locking action. Wearing of the locking mechanism may result in its inability to lock onto the slide rod. Furthermore, the friction-locking action may scratch or otherwise damage the slide rod. 
   Another drawback of the aforesaid easy chair is that the slidable connection between the rear leg unit and the side members does not result in a compact configuration upon folding. 
   SUMMARY OF THE INVENTION 
   The object of this invention is to provide a collapsible chair that is stable in its folding and reclining operations, and that is simple in structure. 
   According to this invention, a collapsible chair comprises a leg frame unit having an upper frame end. The leg frame unit includes a front leg member having an upper end portion, a rear leg member having an upper end portion connected pivotally to the upper end portion of the front leg member, a connector, and an extension limiter. The connector has a first end connected pivotally to the rear leg member, and a second end. The extension limiter has a rear portion connected pivotally to the second end of the connector, and a front portion connected pivotally to the front leg member. 
   The chair further comprises a backrest frame having a lower back portion connected pivotally to the second end of the connector, and a pair of armrests. Each of the armrests has a rear end connected pivotally to the backrest frame, a front end opposite to the rear end in a front-to-rear direction, and an intermediate section between the rear and front ends. 
   At least one coupling device couples the upper frame end of the leg frame unit to the intermediate section of one of the armrests. The coupling device includes a fastener-engaging member secured to the intermediate section of said one of the armrests and formed with a slot that extends in the front-to-rear direction, and an inner fastener having a head and an externally threaded section that extends from the head and through the upper frame end of the leg frame unit and the slot. The coupling device further includes an outer fastener engaging threadedly the externally threaded section. The coupling device arrests movement of the upper frame end of the leg frame assembly relative to the slot when the outer fastener is tightened on the externally threaded section of the inner fastener. 
   A seat member has a front portion and a rear portion, the rear portion being connected pivotally to the second end of the connector. A legrest frame has an upper portion connected pivotally to the front ends of the armrests. The legrest frame is further connected pivotally to the front portion of the seat member. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which: 
       FIG. 1  is an assembled perspective view of a collapsible chair according to a preferred embodiment of the present invention, in which the collapsible chair is shown in a sitting upright position. 
       FIG. 2  is a fragmentary partly exploded perspective view illustrating an armrest assembly of the collapsible chair of  FIG. 1 ; 
       FIG. 3  is a schematic view of the collapsible chair of  FIG. 1 ; 
       FIG. 4  is another schematic view of the preferred embodiment, in which the collapsible chair is shown in a reclining position; 
       FIG. 5  is a schematic view to illustrate a partly folded state of the preferred embodiment; and 
       FIG. 6  is a schematic view to illustrate a completely folded state of the preferred embodiment. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIGS. 1 ,  2 , and  3 , a collapsible chair according to a preferred embodiment of the present invention includes a leg frame unit having a front leg member  3  and a rear leg member  3 ′. The front and rear leg members  3 ,  3 ′ stably support the collapsible chair on the ground. In the preferred embodiment, the front leg member  3  includes a pair of spaced-apart forward legs  31 , and the rear leg member  3 ′ includes a pair of spaced-apart rearward legs  32 . In the preferred embodiment, a forward base support  4  integrally interconnects the two forward legs  31 , and a rearward base support  4 ′ integrally interconnects the two rearward legs  32 . Therefore, the base supports  4 ,  4 ′ rest on the ground such that the front and rear leg members  3 ,  3 ′ are able to support the collapsible chair. Also, with this configuration, the front and rear leg members  3 ,  3 ′ are formed as U-shaped frames. 
   A backrest frame  5  is positioned approximately in the area of the rearward legs  32  of the rear leg member  3 ′, with a lower back portion of the backrest frame  5  positioned between the rearward legs  32  when the collapsible chair is in the sitting upright position of  FIGS. 1 and 3 . Two armrest assemblies  6  have rear ends pivotally connected to the backrest frame  5 , and intermediate sections adjustably connected to the leg frame unit. A legrest frame  8  has an upper portion pivotally connected to front ends of the armrest assemblies  6 . 
   The collapsible chair also includes a seat member having seat supports  7  that extend in a front-to-rear direction between the legrest frame  8  and the backrest frame  5  at a predetermined position under the armrest assemblies  6 . The seat supports  7  have front and rear portions pivotally and respectively connected to the legrest frame  8  and the backrest frame  5 . 
   An upper end portion of each of the forward legs  31  is pivotally connected to an upper end portion of a corresponding one of the rearward legs  32 . In the preferred embodiment, the rearward legs  32  are pivotally connected to the corresponding forward legs  31  at a predetermined distance from extreme ends of the forward legs  31 . 
   Furthermore, an extension limiter  34  and a connector  33  are used to interconnect each of the forward legs  31  to its corresponding rearward leg  32 . In particular, and using one of the forward legs  31  and its corresponding rearward leg  32  as an example, one of the extension limiters  34  has a front portion pivotally connected to the forward leg  31 , a first end  331  of the connector  33  is pivotally connected to the rearward leg  32 , and a rear portion of the extension limiter  34  and a second end  332  of the connector  33  are pivotally interconnected. 
   The extension limiters  34  and the connectors  33  operate such that when the forward legs  31  and the rearward legs  32  are spread apart about the points where they are interconnected as described above, the forward legs  31  and the rearward legs  32  are limited in their spreading degree and are prevented from further movement after a predetermined point. This predetermined degree of spread between the forward legs  31  and the rearward legs  32  is determined by the lengths of the extension limiter  34  and the connector  33 . The extension limiters  34  and the connectors  33  also aid in the folding of the collapsible chair. This will be described in greater detail hereinafter. 
   The backrest frame  5  includes a backrest frame body  51 . The connection of the seat supports  7  to the backrest frame  5  is realized through backrest clasps  52 . In the preferred embodiment, the backrest clasps  52  are substantially U-shaped and are fixed to the backrest frame body  51  at a location below a pivot axis  50  of the armrest assemblies  6 . The backrest clasps  52  embrace the backrest frame body  51 , and ends of the backrest clasps  52  are pivotally connected to the seat supports  7 . 
   Each of the backrest clasps  52  is also connected to the second end  332  of the corresponding connector  33 . Therefore, the rearward legs  32  of the rear leg member  3 ′ are connected to the seat supports  7  and to the backrest frame body  51  of the backrest frame  5 . 
   Each of the armrest assemblies  6  includes an armrest  61 . The armrest  61  has a rear end pivotally connected to the backrest frame  5 , a front end pivotally connected to the legrest frame  8 , and an intermediate section between the front and rear ends and adjustably connected to the leg frame unit. With particular reference to  FIG. 2 , each of the armrest assemblies  6  also includes a coupling device  6 ′ having two fastener-engaging members  62 , and a position-adjusting fastener  63 . The fastener-engaging members  62  extend downwardly from the armrest  61  and toward the corresponding seat support  7 . The fastener-engaging members  62  are spaced apart from each other and extend in the front-to-rear direction. Each of the fastener-engaging members  62  defines a slot  621  that extends along the length of the armrest  61 . 
   The position-adjusting fastener  63  includes an inner fastener  631  and an outer fastener  632 . In the preferred embodiment, the inner fastener  631  is in the form of a bolt with an externally threaded section  634  and a head  633 . The head  633  is sized so that the inner fastener  631  is unable to pass through the slots  621  of the fastener-engaging members  62 . Furthermore, in the preferred embodiment, the outer fastener  632  is in the form of a nut that is internally threaded to engage the externally threaded section  634  of the inner fastener  631 . The outer fastener  632  is sized and shaped to allow for easy manipulation by a user and to abut against the outer fastener-engaging member  62 . 
   Each of the upper ends of the forward legs  31  of the front leg member  3  is inserted between a pair of the fastener-engaging members  62  of the armrest assemblies  6 . A hole is formed in each of the forward legs  31  to allow the inner fastener  631  to pass therethrough, thereby connecting the forward legs  31  to the armrests  61  of the armrest assemblies  6 . 
   The legrest frame  8  includes a legrest frame body  81  and legrest clasps  82 . In the preferred embodiment, the legrest frame body  81  is substantially U-shaped. Further, in the preferred embodiment, the legrest clasps  82  are substantially U-shaped, are fixed to the legrest frame body  81  at a location below the armrest assemblies  6 , and are substantially aligned along the horizontal with the backrest clasps  52  of the backrest frame  5  when the collapsible chair is in the sitting upright position shown in  FIGS. 1 and 3 . The ends of the legrest clasps  82  are pivotally connected to the seat supports  7 . 
   The operation of the collapsible chair structured as described above will now be explained with reference to  FIGS. 4 ,  5 , and  6 . 
   Referring first to  FIG. 4 , assuming that materials or a combination of materials (e.g., fabric secured using a cord) are provided on the backrest frame  5 , the seat supports  7 , and the legrest frame  8  to allow a user to be comfortably seated in the collapsible chair, the user reclines the collapsible chair by loosening the outer fasteners  632  of the position adjusting fasteners  63  and leaning back on the backrest frame  5 . When a desired reclining position is obtained, the user tightens the outer fasteners  632  to secure the collapsible chair in this position. The degree of recline is continuously varied in a stepless manner, and does not involve intermediate preset stages of recline between the sitting upright position shown in  FIG. 1  and the extreme recline position shown in  FIG. 4 . 
   When the user leans back on the backrest frame  5 , the backrest frame  5  pivots about the pivot axis  50  shown in  FIG. 1  such that an upper end of the backrest frame  5  is displaced backward and somewhat downward. During the reclining operation, the degree of spread between the forward legs  31  and the rearward legs  32  remains unaltered. However, the displacement of the backrest frame  5  does vary the positioning of the armrests  61  of the armrest assemblies  6 , the seat supports  7 , and the legrest frame  8 . 
   In greater detail, since the connection of the armrests  61  to the backrest frame  5  is made at a location slightly below a mid-point of the backrest frame  5 , the pivoting of the backrest frame  5  results in lowering the location of the pivot axis  50 , thereby resulting in the lowering of the rear ends of the armrests  61 . The armrests  61  displace along the slots  621  of the coupling devices  6 ′ to result in displacing a distal end of the legrest frame  8  in an upward and outward manner, and in upward tilting of the seat supports  7 . 
   Referring to  FIGS. 5 and 6 , the collapsible chair is folded for transport or storage while in an unseated state, by loosening the outer fasteners  632  and pulling the armrests  61  toward the backrest frame  5 . In view of the ability of all the elements to pivot relative to at least one of the other elements as described above, all of the parts of the collapsible chair move in the direction of the backrest frame  5 , as shown in  FIG. 5 . 
   In particular, the armrests  61  of the armrest assemblies  6  pivot about their connection to the backrest frame  5  such that the front ends of the armrests  61  move upwardly and approach the backrest frame body  51  of the backrest frame  5 . As a result, the legrest frame  8  is moved toward the backrest frame  5 . 
   In addition, by virtue of the pivotable connection between the seat supports  7  and the legrest frame  8 , and between the seat supports  7  and the backrest frame body  51  of the backrest frame  5 , the front portions of the seat supports  7  move upwardly and toward the backrest frame  5 . Finally, due to the pivotable connection between the forward legs  31  and the rearward legs  32 , and that between the forward legs  31  and the armrest assemblies  6  (when the outer fasteners  632  are loosened), the forward legs  31  and the rearward legs  32  move toward each other and toward the backrest frame  5 . 
   After reaching approximately the position shown in  FIG. 5 , the user continues to force the armrests  61  of the armrest assemblies  6  toward the backrest frame  5 . As a result, the elements of the collapsible chair continue in their movements as described above until the collapsible chair becomes completely folded as shown in  FIG. 6 . 
   During the folding operation shown in  FIG. 5 , the second ends  332  of the connectors  33  move away from the rearward legs  32  of the rear leg member  3 ′, then eventually downward such that the second ends  332  of the connectors  33  are positioned below the first ends  331  thereof and adjacent to the rearward legs  32 . This aids in the folding of the collapsible chair by virtue of the pivotable connection of the second ends  332  of the connectors  33  to the extension limiters  34 , the seat supports  7 , and the backrests clasps  52  of the backrest frame  5 . 
   The chair is set up back into the sitting upright position or in a reclining position by performing the above operations in reverse. 
   In the collapsible chair of the present invention, the reclining angle of the back support frame and the height of the leg support frame may be simultaneously adjusted by simple operation of the coupling device. The adjustment is made continuously through a range of reclining positions, and not by using a limited number of pre-established reclining stages. 
   Furthermore, the folding of the collapsible chair is also performed through a simple process involving loosening the position adjusting fasteners and minimally manipulating the chair so that it is folded. 
   The overall securing mechanism of the present invention is simple and very secure, and is structured such that only minimal wearing occurs. 
   While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.