Apparatus and method for forming tapered tubular shafts

Claim 1

A method of forming an elongate tubular tapered shaft that has a interior sidewall surface that is concentrically centered relative to an exterior sidewall surface of said shaft from a plurality of wraps of a sheet thermo-setting resin of tacky consistency that contracts in volume upon polymerizing that has a plurality of laterally spaced, parallel pretensioned fibers enveloped therein that are formed from a material that has a greater tensile strength than said resin when the latter is polymerized and said resin when polymerized having a greater degree of elasticity than said material forming said fibers, which method includes the steps of: a. winding said wraps transversely about a first elongate tapered heat conducting body having first and second end portions, said wraps overlying one another and being intermediately disposed between said first and second end portions, with the tapered external surface of said body between said first and second end portions being that of said interior sidewall surface, said second end of said first body being of smaller transverse cross section than said first end of said first body, said wraps being sufficient in number to provide at least an interior wrap and an exterior wrap when wound on said first body and the fibers in at least one of said wraps being parallel to the longitudinal axis of said shaft; b. sliding said first body and wraps into the confines of a second heat conducting body that defines an elongate interior surface that has a tapered configuration that is the same as said external sidewall surface, said second body having first and second ends, with said second end of smaller transverse cross section than said first end of said second body, and the longitudinal spacing between said first and second ends being greater than the length of said wraps on said first body to provide a longitudinal annulus shaped space between said second end of said first body and said second end of said second body adjacent said second end of the latter; c. maintaining said first body in substantially true concentric relationship with said second body; d. applying a longitudinally directed spring generated force of predetermined constant magnitude to said first body that tends to move said first body and wraps relative to said second body towards said second end of said second body with said predetermined magnitude sufficient to compact said resin in said wraps to define a unified mass but not sufficient to squeeze said resin from between said fibers to permit the latter to physically contact one another; e. heating all of said second body and at least said first end portion of said first body to an elevated temperature at which said resin polymerizes with said resin in said outermost wrap as it polymerizes contracting in volume and allowing said outermost wrap, said first body, and the balance of said wraps to move longitudinally as a unit in said second body towards said second end thereof until the external surface of the polymerized outermost wrap is disposed at a section of said interior surface of said second body that is of substantially the same size and shape as the exterior surface of said first wrap that has said resin therein polymerized; f. continuing to heat said first end portion of said first body for said heat to flow longitudinally therethrough to heat said innermost wrap to a temperature at which said resin therein polymerizes and contracts in volume, with said force as said resin in said innermost wrap contracts moving said first body and said innermost wrap towards said second end of said second body and relative to said second body and outermost wrap to pretension at least a portion of said fibers in said innermost and outermost wraps and in any of said wraps intermediately disposed between said innermost and outermost wraps; g. continuing to heat said second body and at least said first end portion of said first body for heat to flow therefrom through said innermost and outermost wraps to polymerize the resin in intermediately positioned wraps therebetween; h. terminating the application of said force to said first body after said resin in all of said wraps has been polymerized; and i. separating said first and second bodies from said wraps that have had said resin therein polymerized and which now constitute said tubular tapered shaft in which at least a portion of said fibers therein are pre-tensioned and immediately take the major portion of the load when said shaft is transversely flexed.

Claim 2

A method of forming an elongate tubular tapered shaft that has a interior sidewall surface that is concentrically centered relative to an exterior sidewall surface of said shaft from a plurality of wraps of a sheet thermo-setting resin of tacky consistency that contracts in volume upon polymerizing that has a plurality of laterally spaced, parallel pretensioned fibers enveloped therein that are formed from a material that has a greater tensile strength than said resin when the latter is polymerized and said resin when polymerized having a greater degree of elasticity than said material forming said fibers, which method includes the steps of: a. winding said wraps transversely about a first elongate tapered heat conducting body having first and second end portions, said wraps overlying one another and being intermediately disposed between said first and second end portions, with the tapered external surface of said body between said first and second end portions being that of said interior sidewall surface, said second end of said first body being of smaller transverse cross section than said first end of said first body, said wraps being sufficient in number to provide at least an interior wrap and an exterior wrap when wound on said first body and the fibers in at least one of said wraps being parallel to the longitudinal axis of said shaft; b. sliding said first body and wraps into the confines of a second heat conducting body that defines an elongate interior surface that has a tapered configuration that is the same as said external sidewall surface, said second body having first and second ends, with said second end of smaller transverse cross section than said first end of said second body, and the longitudinal spacing between said first and second ends being greater than the length of said wraps on said first body to provide a longitudinal annulus shaped space between said second end of said first body and said second end of said second body adjacent said second end of the latter; c. maintaining said first body in substantially true concentric relationship with said second body; d. applying a longitudinally directed spring generated force of predetermined constant magnitude to said first body that tends to move said first body and wraps relative to said second body towards said second end of said second body with said predetermined magnitude sufficient to compact said resin in said wraps to define a unified mass but not sufficient to squeeze said resin from between said fibers to permit the latter to physically contact one another; e. heating all of said second body and at least said first end portion of said first body to an elevated temperature at which said resin polymerizes with said resin in said outermost wrap as it polymerizes contracting in volume and allowing said outermost wrap, said first body, and the balance of said wraps to move longitudinally as a unit in said second body towards said second end thereof until the external surface of the polymerized outermost wrap is disposed at a section of said interior surface of said second body that is of substantially the same size and shape as the exterior surface of said first wrap that has said resin therein polymerized; f. continuing to heat said first end portion of said first body for said heat to flow longitudinally therethrough to heat said innermost wrap to a temperature at which said resin therein polymerizes and contracts in volume, with said force as said resin in said innermost wrap contracts moving said first body and said innermost wrap towards said second end of said second body and relative to said second body and outermost wrap to pretension at least a portion of said fibers in said innermost and outermost wraps and in any of said wraps intermediately disposed between said innermost and outermost wraps; g. continuing to heat said second body and at least said first end portion of said first body for heat to flow therefrom through said innermost and outermost wraps to polymerize the resin in intermediately positioned wraps therebetween; h. terminating the application of said force to said first body after said resin in all of said wraps has been polymerized; and i. separating said first and second bodies from said wraps that have had said resin therein polymerized and which now constitute said tubular tapered shaft in which at least a portion of said fibers therein are pre-tensioned and immediately take the major portion of the load when said shaft is transversely flexed.