A ski made of synthetic resins composed of upper and lower plates and side plates defining the outer shape of the ski, wherein the upper and lower plates are provided with a plurality of longitudinal ribs at the inner surfaces thereof each having a cross section of a series of projection adapted to mesh with each other provided on the opposing plate, said ribs being provided with such incisions therealong that allow bending of the upper or lower plate without restriction due to the ribs, and the ribs of the upper and lower plates are bonded together to form originally curved ribs while the upper and lower plates are shaped to a required profile in a mold under a heated and compressed condition.
The specification describes a ski with an elongated hollow girder made up of two shells. The two shells are generally U-shaped and have approximately parallel surface parts, with a facing of at least 0.2 mm, in each side wall of the respective ski. These surface parts are connected by a shock absorbing plastic material so as to provide a firm joint between them.
A water ski formed of molded upper and lower shells made of sheet molding compound which have mating and overlapping flanges around the entire perimeter of the shells which are bonded together to form a buoyancy chamber. In one embodiment, the chamber is filled with polymerized foam and in another embodiment longitudinally extending ribs are formed to maintain the upper and lower surfaces of the shells in spaced relationship to each other.
A water ski formed of molded upper and lower shells made of sheet molding compound which have mating and overlapping flanges around the entire perimeter of the shells which are bonded together to form a buoyancy chamber. In one embodiment, the chamber is filled with polymerized foam and in another embodiment longitudinally extending ribs are formed to maintain the upper and lower surfaces of the shells in spaced relationship to each other.
A ski structure having a core comprising: at least one elastic, tough, box-like inner core frame extending longitudinally within the ski throughout the major portion thereof, upper and bottom members enclosing therein said at least one inner core frame and defining at least one space extending longitudinally for the length of the members, excepting the shovel portion of the ski, and being located adjacent to said inner core frame, filling means contained in said space, and binding means made of a tough plastic material enclosing the inner core frame and the filling means to firmly wrap and bind them together. The filling means in different embodiments of the invention is honeycomb material and foamed plastic.
A skateboard structure is provided which is formed of a top piece and a bottom piece, the pieces being formed of appropriate injection molded plastic material, such as polypropylene, polyethylene, polycarbonate, "Plexiglass", or other plastic material which is susceptible to injection molding; or aluminum casting or compression molded fiberglass; or any other material which may be molded or cast. The inner surface of each piece is formed with a lattice-work of integral webs, so that when the pieces are fitted together they define a reinforcing honeycomb-like core.
