Vertical folding shelf

Abstract

A type of foldable shelving rack that includes a folding rack and shelf units. Each level of the folding rack is formed by the hinging together a pair of U-shaped bars. The end of the upper U-shaped bar is hinged to the lower U-shaped bar, thereby forming multiple shelves comprising the foldable shelving unit. A positioning mechanism is located on the opposing hinged ends of the quadrilateral structure; each shelf unit rests between the middle sections of the two U-shaped bars, thus forming a stable and integrated unit that can be folded up.

1 . (canceled) 
     
     
         2 . The foldable shelving rack of  claim 9 , wherein there is a pair of U-shaped bars on the bottom level of the foldable rack, with the two parallel curved sections connected by bars, and a narrow shelving unit resting on the two connecting bars. 
     
     
         3 . The foldable shelving rack of  claim 2 , wherein the two sides of the narrow shelving unit have a downward-facing curved edge; where this curved edge is longer than the semi-circular shape of the connecting bar, and secures into position by attaching onto the connecting bar. 
     
     
         4 . The foldable shelving rack of  claim 3 , wherein a number of handles are located on the middle sections of both ends of the above-stated narrow shelving unit. 
     
     
         5 . The foldable shelving rack of  claim 9 , wherein the shelving units consist of metal trays with extended edges on two sides allowing for the tray edges to rest on the middle sections of the U-shaped bars; a number of handles extend from the middle section of the two ends; and the metal trays are constructed in any of one of the group of a steel-wire tray, a woven steel tray, or a standard basket. 
     
     
         6 . The foldable shelving rack of  claim 9 , wherein:
 the positioning mechanism comprises a working piece with a grip and a fixed piece;   on one end, the working piece is hinged at the hinge point of the quadrangle structure;   in the middle, the hinged piece is hinged onto the fixed piece and the other end of the working piece has a protrusion near the grip that is used for locking   on the one end, the fixed piece is hinged onto the opposing hinge of the quadrangle structure, on the other end, it is hinged to the working piece, as mentioned above;   the middle part of the fixed piece is provided with a hole corresponding to the protrusion located on the working piece; and   when the shelving unit is in open position, the grip is pushed and the protrusion on the working piece slides into the hole, forming a lock.   
     
     
         7 . The foldable shelving rack of  claim 9 , wherein
 the positioning mechanism is attached in a vertical position.   
     
     
         8 . The foldable shelving rack of  claim 1 , wherein the positioning mechanism is a rigid latch or a hinge. 
     
     
         9 . A foldable shelving rack that includes a folding rack and shelf units;
 the shelving rack has a multilevel structure, with each level holding a removable shelf unit;   wherein each level of the folding rack is formed by the hinging together a symmetric pair of U-shaped bars;   said U-shaped bars each having a middle section between two opposing, parallel sections;   each parallel section of an upper level U-shaped bar is rotatingly connected directly to a portion of the parallel sections of a lower level U-shaped bar below the upper level U-shaped bar at a connection point, thereby forming the multiple shelves of the foldable shelving unit;   a positioning mechanism is connected from the hinge on the upper level U-shaped bar and the hinge on the lower level U-shaped bar or is connected between the connection points of the lower level U-shaped bar, wherein when said positioning mechanism is in a first position, the hinge of the upper level U-shaped bar is fixed in position relative to said lower level U-shaped bar hinge and when said positioning mechanism is in a second position the upper level U-shaped bar hinge can move relative to said the lower level U-shaped bar hinge; and   a removable shelf unit is connected on each level by placing the respective shelf on top of a pair of the U-shaped bars' middle sections for each level.   
     
     
         10 . The foldable shelf of  claim 9 , wherein distance between the upper level U-shaped bar connection points is narrower than a width of a shelf mounted to the upper level U-shaped bar. 
     
     
         11 . The foldable shelf of  claim 9 , wherein on each level, one parallel section of the upper level U-shaped bar connection points is inside of one parallel section of the lower level U-shaped bar, and one parallel section of the upper level U-shaped bar connection points is outside of one parallel section of the lower level U-shaped bar. 
     
     
         12 . A foldable shelving rack that includes a folding rack and shelf units;
 the shelving rack has a multilevel structure, with each level holding a removable shelf unit;   wherein each level of the folding rack is formed by the hinging together a symmetric pair of U-shaped bars;   said U-shaped bars each having a middle section between two opposing, parallel sections;   each end of an upper level U-shaped bar is rotatingly connected at the end of the parallel sections to a lower level U-shaped bar below the upper level U-shaped bar at a connection point, thereby forming the multiple shelves of the foldable shelving unit;   a positioning mechanism is connected between the connection points of the lower level U-shaped bar;   wherein when said positioning mechanism is in a first position, the hinge of the upper level U-shaped bar is fixed in position relative to said lower level U-shaped bar hinge and when said positioning mechanism is in a second position the upper level U-shaped bar hinge can move relative to said the lower level U-shaped bar hinge; and   a removable shelf unit is connected on each level by placing the respective shelf on top of a pair of the U-shaped bars' middle sections for each level.