Supporting frame foldable multiple times

Abstract

A foldable supporting frame includes a first frame set, a second frame set, and a first link at each of the left and right sides of the foldable supporting frame to pivotally connect the first frame set with the second frame set. Each of the first and second frame sets includes a first frame unit, a second frame unit, and a second link at each of the left and right sides of the foldable supporting frame to pivotally connect the first frame unit with the second frame unit. The first link allows the first and second frame sets to fold and unfold with respect to each other, and the second link allows the first and second frame units to fold and unfold with respect to each other. As a result, the supporting frame can be folded at least three times and has a much smaller folded size.

What is claimed is: 
     
         1 . A foldable supporting frame, comprising:
 a first frame set;   a second frame set; and   a first link at each of left and right sides of the foldable supporting frame to pivotally connect the first frame set with the second frame set, thereby allowing the first and second frame sets to fold and unfold with respect to each other,   wherein each of the first and second frame sets comprises:
 a first frame unit; 
 a second frame unit; and 
 a second link at each of the left and right sides of the foldable supporting frame to pivotally connect the first frame unit with the second frame unit, thereby allowing the first and second frame units to fold and unfold with respect to each other. 
   
     
     
         2 . The foldable supporting frame of  claim 1 , wherein the first and second frame sets are substantially the same and disposed symmetrically with respect to each other. 
     
     
         3 . The foldable supporting frame of  claim 1 , wherein:
 the first frame unit comprises a first upper frame, a first lower frame, and a first plurality of supports, wherein
 the first upper frame comprises a first upper peripheral longitudinal bar at each of the left and right sides of the foldable supporting frame; 
 the first lower frame comprises a first lower peripheral longitudinal bar at each of the left and right sides of the foldable supporting frame; and 
 each support in the first plurality of supports is disposed between and pivotally connected to the first upper peripheral longitudinal bar of the first upper frame and the first lower peripheral longitudinal bar of the first lower frame; 
   the second frame unit comprises a second upper frame, a second lower frame, and a second plurality of supports, wherein
 the second upper frame comprises a second upper peripheral longitudinal bar at each of the left and right sides of the foldable supporting frame; 
 the second lower frame comprises a second lower peripheral longitudinal bar at each of the left and right sides of the foldable supporting frame; and 
 each support in the second plurality of supports is disposed between and pivotally connected to the second upper peripheral longitudinal bar of the second upper frame and the second lower peripheral longitudinal bar of the second lower frame; 
   the second link at each of the left and right sides of the foldable supporting frame comprises a second upper link and a second lower link, wherein
 the second upper link pivotally connects the first upper peripheral longitudinal bar of the first frame unit with the second upper peripheral longitudinal bar of the second upper frame at proximal end portions thereof; and 
 the second lower link pivotally connects the first lower peripheral longitudinal bar of the first frame unit with the second lower peripheral longitudinal bar of the second upper frame at proximal end portions thereof; and 
   the first link at each of the left and right sides of the foldable supporting frame comprises a first upper link and a first lower link, wherein
 the first upper link pivotally connects the second upper peripheral longitudinal bar of the second frame unit of the first frame set with the second upper peripheral longitudinal bar of the second frame unit of the second frame set; and 
 the first lower link pivotally connects the second lower peripheral longitudinal bar of the second frame unit of the first frame set with the second lower peripheral longitudinal bar of the second frame unit of the second frame set. 
   
     
     
         4 . The foldable supporting frame of  claim 3 , wherein at each of the left and right sides of the foldable supporting frame, the first lower link comprises a bent upper portion, wherein when the foldable supporting frame is unfolded, the bent upper portion of the first lower link is disposed above the second upper peripheral longitudinal bar of the second frame unit of the first frame set and above the second upper peripheral longitudinal bar of the second frame unit of the second frame set, serving as a stopper to prevent the second lower frames of the second frame units of the first and second frame sets beyond their unfolded positions from further rotating beyond their unfolded positions. 
     
     
         5 . The foldable supporting frame of  claim 3 , wherein at each of the left and right sides of the foldable supporting frame, the first upper link comprises an upper portion and a lower portion, the upper portion of the first upper link pivotally connects the second upper peripheral longitudinal bars of the second frame units of the first and second frame sets, wherein the first link further comprises:
 a first middle link for each of the first and second frame sets, wherein the first middle link has a first end portion pivotally connected to the lower portion of the first upper link and a second end portion pivotally connected to a middle portion of an adjacent support of the second frame unit of the first or second frame set.   
     
     
         6 . The foldable supporting frame of  claim 3 , wherein at each of the left and right sides of the foldable supporting frame and for each of the first and second frame sets, the second upper link comprises a bent lower portion, wherein when the foldable supporting frame is unfolded, the bent lower portion of the second upper link is disposed below the first upper peripheral longitudinal bar of the first upper frame and the second upper peripheral longitudinal bar of the second upper frame, serving as a stopper to prevent the first and second upper frames beyond their unfolded positions from further rotating beyond their unfolded positions. 
     
     
         7 . The foldable supporting frame of  claim 3 , wherein at each of the left and right sides of the foldable supporting frame and for each of the first and second frame sets, the second lower link comprises an upper portion and a lower portion, the lower portion of the second lower link pivotally connects the first lower peripheral longitudinal bar of the first lower frame and the second lower peripheral longitudinal bar of the second lower frame, wherein the second link further comprises:
 a second middle link for each of the first and second frame units, wherein the second middle link has a first end portion pivotally connected to the upper portion of the second lower link and a second end portion pivotally connected to a middle portion of an adjacent support of the first or second frame unit.   
     
     
         8 . The foldable supporting frame of  claim 3 , wherein:
 the second upper link of the second link and the first lower link of the first link are substantially the same, and disposed upside down with respect to each other; and   the second lower link of the second link and the first upper link of the first link are substantially the same, and disposed upside down with respect to each other.   
     
     
         9 . The foldable supporting frame of  claim 3 , wherein for each of the first and second frame sets:
 the first upper frame further comprises a first upper peripheral lateral bar integrally formed with the first upper peripheral longitudinal bar at each of the left and right sides of the foldable supporting frame, wherein the first upper peripheral lateral bar and the first upper peripheral longitudinal bar at each of the left and right sides of the foldable supporting frame collectively form a substantially U-shaped upper peripheral frame; and   the first lower frame further comprises a first lower peripheral lateral bar integrally formed with the first lower peripheral longitudinal bar at each of the left and right sides of the foldable supporting frame, wherein the first lower peripheral lateral bar and the first lower peripheral longitudinal bar at each of the left and right sides of the foldable supporting frame collectively form a substantially U-shaped lower peripheral frame.   
     
     
         10 . The foldable supporting frame of  claim 9 , wherein for each of the first and second frame sets, the first U-shaped upper and lower peripheral frames are substantially the same as each other. 
     
     
         11 . The foldable supporting frame of  claim 9 , wherein for each of the first and second frame sets, each of the first U-shaped upper and lower peripheral frames is made of a bent bar. 
     
     
         12 . The foldable supporting frame of  claim 3 , wherein at each of the left and right sides of the foldable supporting frame and for each of the first and second frame sets, the second upper and lower peripheral longitudinal bars are substantially the same as each other. 
     
     
         13 . The foldable supporting frame of  claim 3 , wherein at each of the left and right sides of the foldable supporting frame and for each of the first and second frame sets:
 the first lower peripheral longitudinal bar has a length different than that of the first upper peripheral longitudinal bar; and   the second lower peripheral longitudinal bar has a length different than that of the second upper peripheral longitudinal bar.   
     
     
         14 . The foldable supporting frame of  claim 3 , wherein at each of the left and right sides of the foldable supporting frame and for each of the first and second frame sets:
 the first lower peripheral longitudinal bar has a length shorter than that of the first upper peripheral longitudinal bar; and   the second lower peripheral longitudinal bar has a length longer than that of the second upper peripheral longitudinal bar.   
     
     
         15 . The foldable supporting frame of  claim 14 , wherein at each of the left and right sides of the foldable supporting frame and for each of the first and second frame sets, the second link further comprises:
 a connecting piece for each of the first and second upper frames, and fixedly coupled to the first upper peripheral longitudinal bar of the first frame unit or the second upper peripheral longitudinal bar of the second upper frame at the proximal end portion thereof, wherein the connecting piece is bent with a lug to pivotally connect the second upper link.   
     
     
         16 . The foldable supporting frame of  claim 15 , wherein at each of the left and right sides of the foldable supporting frame and for each of the first and second frame sets, when the foldable supporting frame is folded, the second lower link is received in a space defined by the second upper link, the connecting piece fixedly coupled to the first upper peripheral longitudinal bar of the first upper frame unit, and the connecting piece fixedly coupled to the second upper peripheral longitudinal bar of the second upper frame unit. 
     
     
         17 . The foldable supporting frame of  claim 3 , wherein a support in the first or second plurality of supports comprises a first segment and a second segment collectively forming a substantially “L” shape. 
     
     
         18 . The foldable supporting frame of  claim 17 , wherein the support further comprises one or more third segments extended and bent from an edge of the first segment, wherein the second segment and the one or more third segments are located on the same side of the first segment, wherein the one or more third segments abut the first upper and lower peripheral longitudinal bars or abut the second upper and lower peripheral longitudinal bars when the foldable supporting frame is unfolded. 
     
     
         19 . The foldable supporting frame of  claim 3 , wherein:
 the first upper frame further comprises one or more upper interior bars;   the first lower frame further comprises one or more lower interior bars corresponding to the one or more upper interior bars; and   the first frame unit further comprises one or more supports, each disposed between and pivotally connected to a respective upper interior bar in the one or more upper interior bars and a corresponding lower interior bar in the one or more lower interior bars.   
     
     
         20 . The foldable supporting frame of  claim 3 , wherein:
 the second upper frame further comprises one or more upper interior bars;   the second lower frame further comprises one or more lower interior bars corresponding to the one or more upper interior bars; and   the second frame unit further comprises one or more supports, each disposed between and pivotally connected to a respective upper interior bar in the one or more upper interior bars and a corresponding lower interior bar in the one or more lower interior bars.