Method of manufacturing two tubes simultaneously and machine for use therein

A method of manufacturing a tube having a hollow interior for housing an axle shaft, which transmits rotational motion from a prime mover to a wheel of a vehicle, with the tube formed in at least a first machine and a second machine each having a fixed base and a press structure movable toward the fixed base of the first machine, a first die assembly coupled to the fixed base of the first machine, a second die assembly coupled to the fixed base of the first machine and further defined as an initial stage second die assembly and a later stage second die assembly, a first mandrel coupled to the press structure of the first machine, a second mandrel coupled to the press structure of the first machine and spaced from the first mandrel further defined as an initial stage second mandrel and a later stage second mandrel, a third die assembly coupled to the fixed base of the second machine, and a third mandrel coupled to the press structure of the second machine, said method comprising the steps of:

• placing a first billet into a cavity of the first die assembly;
• placing a first pre-formed billet having a bore defined in one end thereof into a cavity of the initial stage second die assembly;
• placing a first preliminarily extruded tube having a hollow interior into a cavity of the later stage second die assembly;
• placing a first extruded tube into a cavity of the third die assembly;
• moving the press structure of the first machine toward the fixed base after the steps of placing the first billet into the first die assembly, placing the first pre-formed billet into the initial stage second die assembly, and placing the first preliminarily extruded tube into the later stage second die assembly such that the first mandrel contacts the first billet in the first die assembly, the initial stage second mandrel contacts the first pre-formed billet in the initial stage second die assembly, and the later stage second mandrel contacts the first preliminarily extruded tube in the later stage second die assembly to complete the steps of;
• forming the first billet within the cavity of the first die assembly to produce a second pre-formed billet having a bore defined in one end thereof, and
• extruding the first pre-formed billet within the cavity of the initial stage second die assembly to produce a second preliminarily extruded tube having a hollow interior;
• extruding the first preliminarily extruded tube within the cavity of the later stage second die assembly to produce a second extruded tube;
• moving the press structure of the second machine toward the fixed base after the step of placing the first extruded tube into the cavity of the third die assembly to complete the step of;
• drawing the first extruded tube within the cavity of the third die assembly to produce a drawn tube having a wall that has a thickness that is reduced relative to the first extruded tube.

A manufacturing system for manufacturing a tube that has a hollow interior for housing an axle shaft, which transmits rotational motion from a prime mover to a wheel of a vehicle, with said manufacturing system comprising:

• a first machine comprising:
• a fixed base;
• a first die assembly coupled to said fixed base and defining a cavity therein with said first die assembly configured to form a bore in an end of a billet to produce a pre-formed billet;
• an initial stage second die assembly coupled to said fixed based spaced from said first die assembly and defining a cavity therein with said initial stage second die assembly configured to extrude the pre-formed billet into a preliminarily extruded tube;
• a later stage second die assembly coupled to said fixed based spaced from said initial stage second die assembly and defining a cavity therein with said later stage second die assembly configured to extrude the preliminarily extruded tube into an extruded tube;
• a press structure moveable toward and then away from said fixed base with said press structure comprising;
• a first mandrel aligned with said cavity of said first die assembly, and
• an initial stage second mandrel aligned with said cavity of said initial stage second die assembly;
• a later stage second mandrel aligned with said cavity of said later stage second die assembly;
• wherein said first mandrel and said initial and later stage second mandrels move simultaneously with each other as said press structure moves towards and then away from said fixed base such that said first mandrel enters said cavity of said first die assembly, said initial stage second mandrel enters said cavity of said initial stage second die assembly, and said later stage second mandrel enters said cavity of said later stage second die assembly as said press structure moves towards said fixed base;
• and
• a second machine comprising:
• a fixed base;
• a third die assembly coupled to said fixed base and defining a cavity therein, with said third die assembly configured to draw the extruded tube to produce a drawn tube;
• a press structure moveable toward and then away from said fixed base with said press structure comprising;
• a third mandrel coupled to said press structure and aligned with said cavity of said third die assembly;
• wherein said third mandrels moves with said press structure as said press structure moves towards and away from said fixed base such that said third mandrel enters said cavity of said third die assembly as said press structure moves towards said fixed base.