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An integrally molded plastic structural unit includes spaced support members joined by a web section disposed therebetween, each of the support members including spaced face sections and an intermediate section therebetween. Each face section includes a stressed hard outer skin. The intermediate sec

An integrally molded plastic structural unit includes spaced support members joined by a web section disposed therebetween, each of the support members including spaced face sections and an intermediate section therebetween. Each face section includes a stressed hard outer skin. The intermediate section includes a peripheral frame section of high density. The web section includes high density connector members extending between adjoining face sections of the spaced support members. Each of the support members includes mateable sections along at least two edges thereof, with each of the mateable sections including at least five alternating raised and recessed areas forming an asymmetrical pattern along the length of each mateable section. The pattern is the same or a reverse pattern thereof along each mateable section of the same unit and of adjacent units with which it will be assembled. The mateable sections extend beyond the face members or are recessed below the face members on the edges of the unit a substantially equal distance. Also, a method of molding the structural unit.

대표청구항 ▼

An integrally molded plastic structural unit including spaced support members joined by a web section disposed therebetween, each of said support members including spaced face sections and an intermediate section therebetween, each face section including a stressed hard outer skin, said intermediate

An integrally molded plastic structural unit including spaced support members joined by a web section disposed therebetween, each of said support members including spaced face sections and an intermediate section therebetween, each face section including a stressed hard outer skin, said intermediate section including a peripheral frame section of high density, said web section including high density connector members extending between adjoining face sections of said spaced support members, each of said support members including mateable sections along at least two edges thereof, each of said mateable sections including at least five alternating raised and recessed areas forming an asymmetrical pattern along the length of each mateable section, the pattern being the same or a reverse pattern thereof along each mateable section of the same unit and of adjacent units with which it will be assembled, said mateable sections extending beyond said face sections or being recessed below said face sections on said edges of said unit a substantially equal distance; whereby adjacent units are interconnected by engaging a recessed mateable section of one unit with a raised mateable section of an adjacent unit or vice versa. A continuous method of molding a structural unit including the steps of continuously advancing raw materials from a plurality of reservoirs independently to a mixing chamber located closely adjacent to a mold assembly including separable mold sections, introducing said raw materials into said mixing chamber, passing a freshly formed mixture flowing from said mixing chamber directly into a cavity of said adjacent mold assembly in a preselected and monitored flow rate profile, rotating said mold assembly about at least three intersecting axes in a preselected and monitored rotational profile, initially flowing said mixture over surfaces of said mold cavity by said rotational movement to form a hard skin surface, flowing additional quantities of said mixture to peripheral edges of said mold cavity, forming therewith an integral high density peripheral frame section, monitoring and coordinating in a preselected profile the delivery of raw materials to said mixing chamber, the resulting mixture flowing therefrom and the multiple axis rotation of said mold assembly, separating said mold sections of said mold assembly after said unit has formed said mold cavity, removing a molded unit from said separated mold sections, closing said mold sections and repeating said steps to form a multiplicity of such molded units on a continuing basis.