Abstract: An elevated floor panel is disclosed in which a lower sheet metal element is formed with a plurality of projections extending from the lower plane of the panel to the upper planar surface. The projections are formed in sequential die drawing operations. In the first die drawing operation, square truncated pyramids of intermediate height are drawn so that the upper surfaces of the intermediate projections provide substantially unworked material. In the second drawing operation, four symmetrically arranged, semispherical projections are drawn from the unworked material at the tops of the preliminary projections. In one embodiment, the tops of the semispherical projections are flattened. In another embodiment, the semispherical projections formed in the second drawing operation are fully curved. In such embodiment, a third operation is performed to produce a flattened extremity.

Abstract: An elevated floor panel is disclosed formed of a sheet metal upper surface member and a sheet metal lower support member. The lower support member is provided with a plurality of apertures arranged in perpendicular rows across the panel. Integral legs formed of material displaced from the apertures are symmetrically arranged around each aperture and extend laterally to the upper surface member. Each leg is provided with a foot portion welded to the under surface of the surface member. The edges of the lower support member are bent laterally to provide sidewalls extending to the upper surface member and terminating in flanges welded to the upper surface member. The panel structure permits the panel to be supported at its corners and to sustain substantial loads with small load-induced deflections.

Abstract: A tennis practice apparatus consisting of an enclosure providing a playing area and having a regulation-height net member at one end located in front of a cage-like structure forming the end of the apparatus. This cage-like structure is arranged to cause a ball passing rearwardly over the net member to drop into the lower portion of the structure, which is concave and which is provided at its lowest point with a conduit connection leading to a pneumatic ball collecting and propelling mechanism having an outlet conduit directed so as to project balls forwardly over the net toward a player. The mechanism has an upper compartment with an inclined ramp element leading to a rotary ball-feeding member operated by a Geneva-type driving system acting to sequentially feed balls into registry with an outlet duct and a valved aperture in a partition wall between said upper compartment and a lower compartment.