Method of making a fiber reinforced plastic article

Claim 1

A method of molding an elongated solid plastic threaded rod containing continuous reinforcing fibers extending throughout the longitudinal cross section thereof, said rod having a helical screw thread integrally molded on the longitudinal periphery thereof, and said continuous fibers in the peripheral portion of said rod being formed in undulations uniformly within said helical thread throughout the length of said rod from its ends throughout the shank portion thereof and thereby generally conforming to the shape of said thread, and said fibers being present in said threaded rod in an amount of at least about 27 percent of the axial cross sectional area of said rod, said method comprising: a. forming a preform made of a deformable plastic material having continuous reinforcing fibers extending continuously through the axial portion thereof, and the peripheral fibers of said preform being permanently distorted in said preform in a helical manner in an amount corresponding to at least onefourth of a convolution throughout the length of said preform, and said fibers being present in an amount of at least about 27 percent of the axial cross sectional area of said preform; b. compressing said preform with axial force in an enclosed mold zone having a shape corresponding to said plastic article to cause said elongated preform to shorten in length and expand such that peripheral portions of said preform containing said continuous helically distorted fibers distort to correspond to the interior of said mold zone to form said thread, said fibers in said thread being in the form of undulations to yield a molded shape of said threaded rod; and c. solidifying said molded shape to yield said plastic article.

Claim 2

A method of molding an elongated solid plastic threaded rod containing continuous reinforcing fibers extending throughout the longitudinal cross section thereof, said rod having a helical screw thread integrally molded on the longitudinal periphery thereof, and said continuous fibers in the peripheral portion of said rod being formed in undulations uniformly within said helical thread throughout the length of said rod from its ends throughout the shank portion thereof and thereby generally conforming to the shape of said thread, and said fibers being present in said threaded rod in an amount of at least about 27 percent of the axial cross sectional area of said rod, said method comprising: a. forming a preform made of a deformable plastic material having continuous reinforcing fibers extending continuously through the axial portion thereof, and the peripheral fibers of said preform being permanently distorted in said preform in a helical manner in an amount corresponding to at least onefourth of a convolution throughout the length of said preform, and said fibers being present in an amount of at least about 27 percent of the axial cross sectional area of said preform; b. compressing said preform with axial force in an enclosed mold zone having a shape corresponding to said plastic article to cause said elongated preform to shorten in length and expand such that peripheral portions of said preform containing said continuous helically distorted fibers distort to correspond to the interior of said mold zone to form said thread, said fibers in said thread being in the form of undulations to yield a molded shape of said threaded rod; and c. solidifying said molded shape to yield said plastic article.

Claim 9

A method of molding an elongated plastic article having a helical screw thread positioned on its periphery, from an elongated preform made of a deformable plastic material having reinforcing fibers longitudinally extending therethrough, comprising: a. molding a preform of said deformable plastic material which contains said continuous fibers in an amount of at least about 27 percent of the axial cross sectional area of the preform; b. distorting said elongated preform by torsion causing fibers in the peripheral portions thereof to permanently helically distort within said preform such that when subjected to axial force they will continue their helical deformation and expand radially of said preform; c. applying axial compressive force on the said distorted preform within an enclosed mold zone, causing said preform to shorten in length and expand such that peripheral portions thereof containing said helically distorted fibers are distorted into the shape of said screw thread and thereby conform to thE interior of said mold zone, said peripheral portions having corresponding undulations of fibers formed therein, to thereby yield a molded shape of said plastic article; and solidifying said molded shape to yield said plastic article.

Claim 10

A method of molding an elongated plastic article having a helical screw thread positioned on its periphery, from an elongated preform made of a deformable plastic material having reinforcing fibers longitudinally extending therethrough, comprising: a. molding a preform of said deformable plastic material which contains said continuous fibers in an amount of at least about 27 percent of the axial cross sectional area of the preform; b. distorting said elongated preform by torsion causing fibers in the peripheral portions thereof to permanently helically distort within said preform such that when subjected to axial force they will continue their helical deformation and expand radially of said preform; c. applying axial compressive force on the said distorted preform within an enclosed mold zone, causing said preform to shorten in length and expand such that peripheral portions thereof containing said helically distorted fibers are distorted into the shape of said screw thread and thereby conform to thE interior of said mold zone, said peripheral portions having corresponding undulations of fibers formed therein, to thereby yield a molded shape of said plastic article; and solidifying said molded shape to yield said plastic article.