초록 ▼

A structural lumber alternative made of thermoplastic material has a generally hollow cross section, with a thick outer shell enclosing a central opening and at least one internal web disposed in the central opening and joining the outer shell. The internal web is a non-extruded unitary web of the s

A structural lumber alternative made of thermoplastic material has a generally hollow cross section, with a thick outer shell enclosing a central opening and at least one internal web disposed in the central opening and joining the outer shell. The internal web is a non-extruded unitary web of the same material forming the outer shell and is formed into position from the outer shell after the extruded outer shell leaves the extrusion device.

대표청구항 ▼

[ What is claimed is:] [1.] A structural lumber alternative comprising:an extruded member of thermoplastic material having a length which is substantially greater than its cross sectional dimension, the cross section of the extruded member being generally rectangular and hollow having four exterior

[ What is claimed is:] [1.] A structural lumber alternative comprising:an extruded member of thermoplastic material having a length which is substantially greater than its cross sectional dimension, the cross section of the extruded member being generally rectangular and hollow having four exterior walls surrounding a central opening, the exterior walls being sufficiently thick and workable to withstand the operations of sawing, nailing, screwing, and gluing;at least one longitudinal web through the central opening joining two opposed walls of the extruded member, the internal web being a unitary non-extruded web characterized by a non-extruded herringbone surface and formed of the same melt which formed the walls; andthe internal web lending sufficient structural rigidity to the extruded member so that the extruded member has strength and weight characteristics comparable to those of lumber.