Construction plate has interlocking rebate along two opposite parallel edges with inner ledge, ramp and outer ledge with tongued and groove formation along ramps

摘要

The construction plate has on at least two opposite parallel edges a rebate for keyed connection with an adjoining plate. The rebate is stepped and on one edges drops from one plane and on the other edge drops from the other plane to form an inner ledge (12,22), a ramp (14, 24) and an outer ledge (16, 26). The tongued and groove formation is along the ramps. The ledges are preferably at right angles to the planes. The steps can be about half as thick as the plate.