Joint element to support and secure shelves in a bookcase or stand, and a set of shelves employing said joint elements to support and secure the shelves between the uprights

A shelf assembly comprising:

• two vertically disposed, spaced apart uprights having respective opposed facing faces;
• a respective recess defined in each of the faces for being opposite a recess in the other face, whereby the two recesses are paired to cooperate, each of said recesses in said uprights having an opening at said face and each said recess extending obliquely downward into the respective upright away from the other upright;
• a shelf disposed between the uprights, the shelf having a lower surface;
• the shelf having opposite ends at the uprights;
• a respective recess into the lower surface of the shelf spaced inward from each of the ends, and extending upward into the shelf and being accessible through the lower surface;
• and
• a respective joint element for each end of the shelf for joining the shelf to both uprights, each joint element comprising a wire bent in one plane to form a bent section including a first upstanding inserting part for insertion from below into the respective recess in the shelf;
• the bent section also including a supporting section which extends from the first inserting part along the lower surface of the shelf toward the upright, the bent section having an end slightly inward from the shelf end at that upright, and
• a second inserting part which extends obliquely downward from the end of the bent section, the second inserting part of each respective joint element being receivable in the respective oblique recess of the respective upright, each second inserting part thereby extending obliquely to a point slightly inward from the shelf end at the respective upright to the end of the bent section so that said joint elements pull the uprights together and toward the ends of the shelf when the shelf is loaded.