Variable orifice, zero friction draw die

Claim 2

Apparatus for tapering elongated workpieces comprising: support structure; at least three spaced circular disc dies connected in the support structure; die peripheries formed on the circumferences of the disc dies wherein the die peripheries constitute a substantially uninterrupted die orifice and the planes of the disc dies intersect in a mutual straight line that passes through die orifice center; means to tension the workpiece at a stress slightly above the yield point of the workpiece material; rotating means for synchronously rotating the disc dies when the workpiece is being tapered; and means to move said workpiece through said orifice at a linear speed substantially identical to the rotary speed of said disc dies.

Claim 3

The structure according to claim 1 wherein the die peripheries are of variable-depth so as to constitute a variable die orifice.

Claim 4

The structure according to claim 1 wherein the disc dies are equiangularly spaced.

Claim 5

The structure according to claim 1 wherein the die peripheries are flat in cross section so as to make workpieces of polygonal cross section.

Claim 6

The structure according to claim 1 wherein the die peripheries are concave so as to make workpieces or round cross section.

Claim 7

The structure according to claim 1 wherein the circumference of each disc die is formed with beveled peripheries on opposite sides of the die peripheries, the beveled peripheries of adjacent dies being in rolling contact.

Claim 8

The structure according to claim 6 wherein the rotating means comprises beveled gears formed on the beveled peripheries, the adjacent beveled gears being intermeshed so that rotary movement of one disc rotates the other discs.

Claim 9

The structure according to claim 6 wherein the rotary means comprises a drive shaft connected to each disc die, all of the drive shafts being connected to a common actuator capable of rotating the drive shafts simultaneously.

Claim 10

The structure according to claim 1 wherein there are four disc dies whose circumference are contoured with die peripheries of variable depth.

Claim 11

Apparatus for tapering elongated workpieces comprising: support structure; at least three equiangularly spaced circular disc dies rotatably connected in the support structure; die peripheries of substantially identical variable-depth contouring formed on the circumference of the disc dies wherein the die peripheries constitute a substantially uninterrupted die orifice and the planes of the disc dies intersect in a mutual straight line located in the center of the die orifice; beveled peripheries on the opposite sides of the die peripheries, the beveled peripheries of adjacent disc dies being in rolling contact; means to tension the workpiece at a stress slightly above the yield point of the workpiece material; rotating means for synchronizing the rotations of the disc dies when the workpiece is being tapered; and, means to move said workpiece through said orifice at a linear speed substantially identical to the rotary speed of said disc dies.

Claim 12

Apparatus for tapering elongated workpieces comprising: support structure; at least three equiangularly spaced circular disc dies rotatably connected in the support structure; die peripheries of substantially identical variable-depth contouring formed on the circumference of the disc dies wherein the die peripheries constitute a substantially uninterrupted die orifice and the planes of the disc dies intersect in a mutual straight line located in the center of the die orifice; beveled peripheries on the opposite sides of the die peripheries, the beveled peripheries of adjacent disc dies being in rolling contact; means to tension the workpiece at a stress slightly above the yield point of the workpiece material; rotating means for synchronizing the rotations of the disc dies when the workpiece is being tapered; and, means to move said workpiece through said orifice at a linear speed substantially identical to the rotary speed of said disc dies.