Abstract: An improved clamp apparatus for storing sheets, for example of paper or foil, including especially maps and drawings, the sheets being neither rolled nor folded so that they can be readily inspected, and a considerable number of sheets can be stored without interfering with each other. The sheets are held from above from any convenient rail, by being inserted, singly or multiply in a clamp that may be comparable in length with the sheet the pressure of the clamp being adjusted gradually by means of wing nuts on self locking bolts and being biased by leaf springs.