Adjustable shelf support

Claim 1

A STORAGE RACK COMPRISING A PLURALITY OF VERTICAL LEGS AND A HORIZONTAL POLYGONAL SHELF SUPPORTED THEREBY, SAID SHELF HAVING CORNETS CORRESPONDING NUMERICALLY WITH THE LEGS AND BEING FORMED FROM A UNITARY SHEET OF METAL AS A FLAT SUPPORT SURFACE AND A CONTINUOUS PERIMETRAL FLANGE, SAID FLANGE AT ITS CORNERS BEING BLUNTED, EACH LEG BEING HOLLOW AND HAVING A LONGITUDINAL SURFACE APPROXIMATELY CORRESPONDING IN HORIZONTAL CROSS-SECTIONAL SHAPE WITH THE CORRESPONDING BLUNTED CORNER OF THE SHELF, SAID LONGITUDINAL SURFACE OF EACH LEG BEING ABUTTED BY THE CORRESPONDING BLUNTED CORNER, EACH LEG HAVING A LONGITUDINAL SLOT OPENING THROUGH SAID LONGITUDINAL SURFACE ALONG EDGES EXTENDING CONTINUOUSLY LONGITUDINALLY OF THE LEG, A KEEPER PLATE FOR SAID SHELF SLIDABLE INSIDE EACH LEG AND WIDER THAN THE CORRESPONDING SLOT, AND MEANS PASSING THROUGH SAID SLOT OF EACH LEG CONNECTING TOGETHER ONE BLUNTED CORNER OF THE FLANGE AND THE CORRESPONDING KEEPER PLATE AND TIGHTENABLE TO FRICTIONALLY GRIP THE EDGE PORTIONS OF THE LEG ON EITHER SIDE OF THE SLOT BETWEEN SAID BLUNTED PORTION OF THE FLANGE AND SAID KEEPER PLATE, WHEREBY TO HOLD THE SHELF IN ADJUSTED POSITION AS TO HEIGHT ALONG SAID LEGS AND TO RIGIDLY CONNECT SAID LEGS TOGETHER AND BRACE SAID SHELF.