Patent Publication Number: US-6981741-B2

Title: Portable folding chair

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a chair having a seat and a backrest where the backrest is movable between upright position and a compact position. More particularly, the chair provides back support in situations where a user would otherwise be sitting on a horizontal surface without back support. 
   2. Description of the Prior Art 
   It is known to have chairs without legs having a seat and a backrest where the position of the backrest is adjustable relative to the seat. The backrest moves between an upright position and a folded position relative to the seat. The floor seat is bulky, the backrest doesn&#39;t have a cushion and the backrest is not very secure in an upright position. 
   A floor seat is described in U.S. Pat. No. 2,685,326 issued on Aug. 3, 1954. When moving from an unfolded position to a folded position, the backrest folds forward until a front surface of the backrest lies on an upper surface of the seat. 
   Previous chairs without legs are expensive to manufacture, are too heavy to be easily carried by a user, are too cumbersome even when folded, are unstable as they can tip too easily, are too uncomfortable for use over a long period of time or cannot be used as a chair when they are in a folded position. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a portable folding chair that can be used as a chair in a compact position and in an upright position. It is a further object of the present invention to provide a portable folding chair that can be moved from an upright position to a compact position in which a backrest lies in the same plane as a seat. 
   A chair has a seat and a backrest, the seat having an upper surface and a lower surface, the backrest having a front surface and a rear surface. The chair is readily movable between an upright position and a compact position. In an upright position, the backrest is mounted in a fixed position relative to the seat so that an angle between the upper surface of the seat and the front surface of the backrest is greater than substantially 90°. In the compact position, the angle is much greater than 90° and the seat and the backrest lie substantially in the same plane. 
   Preferably, in a compact position, the angle between the upper surface of the seat and the front surface of the backrest is substantially 180°. 
   A chair has a seat and a backrest. The backrest has an inverted U shape with two legs extending downward from a central portion. Each of the legs has a free end that is slidably connected to either side of the seat, the legs straddling the seat. The backrest lies outside of the seat immediately to the rear and sides thereof when the chair is in a compact position. The backrest is at an angle that is greater than substantially 90° when the chair is in an upright position. 
   Preferably, a pneumatic cylinder extends directly or indirectly between a seat and the free end of each of the legs. 
   A method of moving a chair between a compact position and an upright position uses a chair having a seat and a backrest. The seat has an upper surface and a lower surface, the backrest having a front surface and a rear surface. The seat and backrest are in contact with one another. The method comprises, commencing with the chair in a compact position and the seat and the backrest lying substantially in the same plane, pulling the backrest upward and rearward relative to the seat, manipulating the backrest to lock the backrest in an upright position relative to the seat, subsequently manipulating the backrest to unlock the backrest from the upright position, moving the backrest downward and forward to return the chair to the compact position. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a chair in an upright position; 
       FIG. 2  is a top view of a frame for the seat; 
       FIG. 3  is a top view of a frame for the backrest; 
       FIG. 4  is a side view of a bracket; 
       FIG. 5  is a side view of the chair in a compact position; 
       FIG. 6  is a side view of the chair in an upright position; 
     In  FIG. 7 , there is shown a top view of the chair in a compact position; 
       FIG. 8  is a front view of the chair in an upright position; 
       FIG. 9  is a perspective view of a further embodiment of a chair in an upright position; 
       FIG. 10  is a side view of a bracket for the chair  FIG. 9 ; 
       FIG. 11  is a top view of the chair shown in  FIG. 9  with the cushions removed; and 
       FIG. 12  is a schematic sectional view through the line A—A of  FIG. 11  with the cushion replaced. 
   

   DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
   In  FIG. 1 , a chair  2  has a seat  4  and backrest  6 . The seat  4  has frame  8  with a cushion  10  thereon. Along each side of the seat  4 , there is mounted a bracket  12 . The backrest  6  has a frame  14  with a cushion  16  mounted on an upper portion thereof. The backrest  6  is mounted in contact with the seat  4 . As can best be seen from  FIG. 3 , the frame  14  has two legs  18 ,  20  extending downward from a central portion  21  with a connector  22  extending inward from a free end  23  each of the legs  18 ,  20 . The frame  14  has the shape of an inverted U. A handle  24  is mounted on an outer surface of each of the legs  18 ,  20 . There are two braces  26  that are pivotally mounted at each end of the brace between each leg  18 ,  20  of the frame  14  of the backrest  6  and each side of the frame  8  of the seat  4  to a rear of said backrest. The connectors  22  are tiny posts with an enlarged inner end  28 . The posts  22  slide within a slot  30  of each of the brackets  12  on either side of the seat  4  respectively. The braces  26  provide support for the backrest  6  when it is in an upright position as shown in FIG.  1 . At each corner of the seat  4 , there is located a small pedestal  32  (only one of which is shown in FIG.  1 ). The pedestals  32  raise the seat  4  slightly above any supporting surface (not shown) on which the chair  2  is viewed. In  FIG. 2 , there is shown a top view of the frame  8  of the seat  4 . 
   In  FIG. 4 , there is shown a side view of one of the brackets  12 . The brackets  12  on either side of the chair  2  are mirror images of one another. There are two openings  32  in each of the brackets  12  and the brackets are affixed to the frame  8  of the seat  4  by screws (not shown). The slot  30  is an elongated slot that slopes upward toward a front of the chair  4 . The slot  30  has two inverted L-shaped notches  34 ,  36  extending upward therefrom. In the upright position shown in  FIG. 1 , the backrest  6  is pivotally mounted within the notches  34  via the connectors  22 . 
   In  FIG. 5 , the chair  2  is shown in a compact position. The same reference numerals are used in  FIG. 5  to describe those components that are identical to the components shown in FIG.  1 . It can be seen that there is a pedestal  32  located at each of the upper corners of the backrest  6 . In the compact position, the seat  4  and backrest  6  lie in the same plane. 
   In  FIG. 6 , there is shown a top view of the chair  2  in the compact position. The same reference numerals are used in  FIG. 6  as those used in  FIGS. 1 and 5  for those components that are identical. 
   In  FIG. 7 , there is shown a side view of the chair  2  in the first upright position, being the same upright position as that shown in FIG.  1 . The same reference numerals are used in  FIG. 7  as those used in  FIGS. 1 and 5  to describe those components that are identical. The chair  2  has a second upright position which is shown in  FIG. 7  by dotted lines. In the first upright position, the connectors  22  are pivoted in the notches  34  and in the second upright position, the connectors  22  are pivoted in the notches  36 . The notch  34  is not shown in  FIG. 7  as it is hidden by the side  18  of the backrest  6 . Only one of the notches  36  is shown in FIG.  7 . 
   In  FIG. 8 , there is shown a front view of the chair  2  in the first upright position shown in  FIGS. 1 and 7 . The same reference numerals are used in  FIG. 8  as those used in  FIGS. 1 and 7  to describe those components that are identical. 
   By comparing  FIGS. 2 and 3  with  FIGS. 5 and 6 , it can be seen that when the chair is in a compact position, the frame  14  is aligned with and immediately adjacent to an exterior of a rear member  31  and sides of the frame  8  of the seat  4 . The cushion  16  fills the gap that would otherwise exist between a rear  31  of the frame  8  and the cushion  10  of the seat  4  when the chair  2  is in the compact position. 
   The compact position is the carrying or transporting position of the chair  2 . However, even in the compact position, the chair  2  has an advantage over previous chairs in that the cushions  10 ,  16  of the seat  4  and backrest  16  are oriented side by side in substantially the same plane. An angle between an upper surface  38  of the cushion  10  of the seat  4  and an upper surface  40  of the cushion  16  of the backrest  6  are at an angle of substantially 180° relative to one another. In the first upright position shown in  FIG. 7 , the angle of the upper surface  38  to the front surface  40  is greater than 90° and is substantially 100°. In the second upright position shown in  FIG. 7  by way of dotted lines, the angle is substantially 125°. If desired, the chair could have upright positions at different angles than those shown simply by relocating the notches on the brackets  12 . Further, more than two upright positions could be utilized by locating more than two notches in the brackets  12 . 
   In operation, to move the chair from the compact position shown in  FIG. 5  to each of the two upright positions shown in  FIG. 7 , the backrest is pulled rearward and upward relative to the seat. The connectors  22  slide along the slot  30  until the connectors can be guided into the notch  34 . When the connectors are located properly within the notch  34 , the backrest is locked in the first upright position. To move out of the first upright position, the handles  24  are pulled backward slightly and the connectors are manipulated out of the notch  34 . From that position, the backrest can be pivoted toward the rear and the connectors can slide toward the compact end of the bracket  12  to return the chair to the compact position. Alternatively, after the connectors have been removed from the slot  34 , the handles can be pulled to move to connectors into the slot  36 . When the connectors are properly located within the slot  36 , the backrest will be locked in the second upright position. As can readily be seen from  FIG. 7 , the backrest leans further back in the second upright position than it does in the first upright position. To move the backrest out of the second upright position, the handles  24  are forced slightly rearward until the connectors are back in the main part of the two slots  30 . The chair can then be moved either to the first upright position or back to the compact position. 
   In  FIGS. 9  to  12 , there is shown a further embodiment of a chair  50  that is operable by a pneumatic cylinder  52  located between the seat  4  and backrest  6 . The same reference numerals are used in  FIGS. 9  to  12  as those used in  FIGS. 1  to  8  for those components that are identical.  FIG. 9  is a perspective view of the chair  50  with the pneumatic cylinder  52  shown by dotted lines.  FIG. 10  is a side view of a bracket  54  having a slot  56  that slopes upward toward the front  4  of the chair  50 . In  FIG. 11 , it can be seen that the cylinder  52  has an activator  58  protruding from a front of the frame  8  of the seat  4 . The cylinder  52  spins between the front of the frame  8  of the seat  4  and a cross member  60 . The cross member  60  is slidable above the frame  8  and beneath the cushion  10 . A space is created between the frame  4  and the cushion  10  by four posts  62 , which are best seen in FIG.  12 . Only two of the four posts  62  are shown in FIG.  12 . The posts  62  are located outside the moveable range of the cross member  60 . The cross member  60  has two projections  64 , one projection  64  being located at each end of the cross member. The projections  64  extend through the slot  56  on each of the brackets  54  on either side of the chair  52 . The free end of the legs  18 ,  20  are affixed to the projections  64  so that the backrest straddles the frame  8  in the compact position (not shown in  FIGS. 9  to  12 ). The frame  8  has longitudinal guides  66  extending from front to rear which interact with L-shaped hooks  68  extending downward from the cross member  60 . The hooks  68  and longitudinal guides  66  keep the cross member aligned with the frame  8 . The pneumatic cylinder  52  has an extended position as shown in  FIGS. 9 and 11  and a retracted position (not shown). In the extended position shown, the chair is in an upright position. In the retracted position, the cross member will be moved toward the front of the seat  4 , thereby pulling the legs  18 ,  20  toward the front of the slot  56  and moving the backrest into the compact position. The compact position is not shown for the chair  52 , but is essentially the same as the compact position shown for the chair  2  in  FIGS. 5 and 6 . The only real difference is that the cushion  10  must be raised slightly above the frame  8  as previously stated to allow space for the cross member to move. Since the cylinder  52  has various extended positions, the angle of the backrest relative to the seat can be adjusted to the comfort of the user and readjusted, if desired. Preferably, the cylinder is designed to move to the extended position when the activator  58  is pushed to one side if there is no external force placed on the backrest. Further, the cylinder  52  is designed to retract when the activator  58  is pushed to one side an external force downward on the backrest. When moving the chair to a compacted position from an upright position, the activator  52  is moved to one side and the backrest is simultaneously manually pushed downward until the compact position has been attained. The cushions  10  have been removed in  FIG. 11  to expose the frame  8 . 
   The chair of the present invention has several advantages. The backrest moves from the upright position to the compact position by pivoting the backrest further rearward away from the upper surface  38  of the cushion  10 . If the backrest were moved to the compact position by pivoting the backrest forward, the chair would be at least twice as thick in the folded position than it is in the compact position shown in FIG.  5 . Also, even though the cushion  16  lies side by side with the cushion  10  in the compact position, the length of the chair from front to rear in the compact position is only about 25% greater than the length of the chair from front to rear when the chair is in an upright position. 
   When the chair is in the first upright position, the pivot point of the backrest relative to the seat is at the notch  34 . The distance from the notch  34  to the rear  31  of the frame  8  adds stability to the chair and greatly increases the difficulty of tipping the chair over backward. In the second upright position, the backrest is pivoted at the notch  36  relative to the seat  4 . In this position, even thought the centre of gravity of a user of the chair is moved more toward the rear because the backrest is tilted back further, the greater distance of the notch  36  to the rear member  31  results in the chair being extremely stable. 
   While the chair of the present invention is designed to make “sitting on the floor” much more comfortable to a user, the chair could also be used on flat surfaces to provide back support. If one sits on the floor, without back support, the sitting position soon becomes extremely uncomfortable. With the chair of the present invention, one can sit on the chair, while the chair rests on the floor, relatively comfortably for a much longer period of time. The chair of the present invention is portable and can easily be moved from one location to another and can easily be carried by a user for long distances.