Methods of and apparatus for hydrostatic forming

Claim 3

Method of forming a flange on an end of a tubular member having an initial wall thickness according to claim 1, further including the steps of: maintaining said downstream portion of said tubular member in said state of increased deformability during said forming of said flange.

Claim 4

Apparatus for forming a flange on an end of a tubular member having an initial wall thickness, comprising: a. a supporting member for insertion within said tubular member; b. a die having a die orifice; c. means providing a closed expandable chamber at the exit end of, and communicating with, said die orifice, said chamber being expandable in a direction parallel to the longitudinal axis of said die orifice; d. means for placing said supporting member in operative supporting engagement with the entire periphery of said tubular member between a first station adjacent said die orifice and a second station upstream of the entrance end of said die orifice; e. means for advancing said supporting member through said die orifice whereby by means of said operative engagement between said supporting member and the said inner periphery of said tubular member, the downstream portion of said tubular member is advanced through said die orifice into said closed chamber and against that wall of said closed chamber remote from said die orifice whereby said downstream portion of said tubular member is flared outwardly in said closed chamber, f. said advancing means adapted to continue the advancement of said supporting member thereby to continue to advance said downstream portion of said tubular member into said closed chamber to fill said chamber and to pressurize that portion of said tubular member in said closed chamber whereby to place the said downstream portion of said tubular member in a state of increased deformability; g. means for expanding said closed chamber in a direction parallel to said longitudinal axis of said die orifice upon said downstream portion of said tubular member within said closed chamber attaining said state of increased deformability as the advancement of said supporting member is continued; h. whereby a flange is formed on the downstream portion of said tubular member, which flange has a thickness in a direction parallel to the longitudinal axis of said tubular member which is greater than the initial wall thickness of said tubular member.

Claim 5

Apparatus for forming a flange on an end of a tubular member having an initial wall thickness, comprising: a. a supporting member for insertion within said tubular member; b. a die having a die orifice; c. means providing a closed expandable chamber at the exit end of, and communicating with, said die orifice, said chamber being expandable in a direction parallel to the longitudinal axis of said die orifice; d. means for placing said supporting member in operative supporting engagement with the entire periphery of said tubular member between a first station adjacent said die orifice and a second station upstream of the entrance end of said die orifice; e. means for advancing said supporting member through said die orifice whereby by means of said operative engagement between said supporting member and the said inner periphery of said tubular member, the downstream portion of said tubular member is advanced through said die orifice into said closed chamber and against that wall of said closed chamber remote from said die orifice whereby said downstream portion of said tubular member is flared outwardly in said closed chamber, f. said advancing means adapted to continue the advancement of said supporting member thereby to continue to advance said downstream portion of said tubular member into said closed chamber to fill said chamber and to pressurize that portion of said tubular member in said closed chamber whereby to place the said downstream portion of said tubular member in a state of increased deformability; g. means for expanding said closed chamber in a direction parallel to said longitudinal axis of said die orifice upon said downstream portion of said tubular member within said closed chamber attaining said state of increased deformability as the advancement of said supporting member is continued; h. whereby a flange is formed on the downstream portion of said tubular member, which flange has a thickness in a direction parallel to the longitudinal axis of said tubular member which is greater than the initial wall thickness of said tubular member.

Claim 6

Apparatus for forming a flange on the end of a tubular member having an initial wall thickness according to claim 3, wherein said means for expanding said closed chamber is further adapted for cooperating with said supporting member and said chamber to maintain said downstream portion of said tubular member in said state of increased deformability during said forming of said flange.

Claim 7

Apparatus for forming a flange on an end of a tubular member, which comprises: a mandrel complementary in shape to the interior of said tubular member and for supporting the interior of said tubular member; a pressure vessel having a pressure chamber formed therein and for receiving fluid and said tubular member; an extrusion die for permitting the forced passage therethrough of said mandrel supported tubular member, said extrusion die being complementary in shape to the exterior of said tubular member and being positioned at one end of said pressure chamber; a movable back-up die positioned opposite said extrusion die and having a bore formed therein for receiving a portion of said mandrel; a laterally movable annular member surrounding one end of said back-up die and for confining the outer diameter of said flange to be formed, said extrusion die, said back-up die and said annular member forming cooperatively a variable-sized die cavity of the desired shape of said flange to be formed; and a piston extendable into said pressure chamber for raising the pressure in said fluid to a level sufficiently high to (i), apply hydrostatic pressure on said tubular member sufficiently high so as to place said member in a state of increased deformability, and (ii) to force said end of said tubular member, and successive portions thereof, while in said state, through said extrusion die and into said variable-sized die cavity to form said flange.

Claim 8

Apparatus for forming a flange on an end of a tubular member, which comprises: a mandrel complementary in shape to the interior of said tubular member and for supporting the interior of said tubular member; a pressure vessel having a pressure chamber formed therein and for receiving fluid and said tubular member; an extrusion die for permitting the forced passage therethrough of said mandrel supported tubular member, said extrusion die being complementary in shape to the exterior of said tubular member and being positioned at one end of said pressure chamber; a movable back-up die positioned opposite said extrusion die and having a bore formed therein for receiving a portion of said mandrel; a laterally movable annular member surrounding one end of said back-up die and for confining the outer diameter of said flange to be formed, said extrusion die, said back-up die and said annular member forming cooperatively a variable-sized die cavity of the desired shape of said flange to be formed; and a piston extendable into said pressure chamber for raising the pressure in said fluid to a level sufficiently high to (i), apply hydrostatic pressure on said tubular member sufficiently high so as to place said member in a state of increased deformability, and (ii) to force said end of said tubular member, and successive portions thereof, while in said state, through said extrusion die and into said variable-sized die cavity to form said flange.

Claim 9

Apparatus according to claim 5 wherein said back-up die is self-balancing so as to assist in achieving an even flow of said tubular member into all areas of said variable-sized die cavity, and which is comprised of: a ball member in which said mandrel receiving bore is formed; a socket member for receiving pivotably said ball member; and said ball member, upon the occurrence of an uneven flow into an area of said die cavity, being pivotable in the direction of said area of uneven flow and effective, in cooperation with said mandrel, to tend to restore an even flow of said tubular member into all areas of said variable-sized die cavity.

Claim 10

Apparatus for forming a flange on a tubular member which comprises: a pressure cylinder having a pressure chamber formed therein for receiving fluid; an extrusion die for receiving successive portions of said tubular member and being provided with a centrally formed bore of a configuration substantially complementary to the exterior of said tubular member; the entrance end of said extrusion die bore being slightly smaller than the exterior of said tubular member; a mandrel positioned within said pressure chamber and insertable into said tubular member to provide internal support therefor; the exterior of said mandrel being of a configuration substantially complementary to the interior of said tubular member and said mandrel being extendable through the extrusion die bore; a back-up die positioned opposite said extrusion die and movable away therefrom; an annular member encircling said back-up die and forming, in conjunction with said extrusion die and said back-up die, a variable-sized die cavity of a predeterminable ultimate size and shape substantially complementary to the size and shape of the flange to be formed on said tubular member; a piston extendable into said pressure chamber for increasing the pressure in said fluid sufficiently such that said mandrel suppoRted tubular member is forced through said extrusion die and into engagement with said back-up die to flare outwardly said tubular member into said die cavity; said piston also for increasing the pressure in said fluid sufficiently such that said fluid pressure, in cooperation with said back-up die, (i) applies hydrostatic pressure on said tubular member, including said flared portion, sufficiently high such that said tubular member, including said flared portion, is in a state of increased deformability, and (ii) forces successively portions of said tubular member, in said state, through said extrusion die and into said variable-sized die cavity; and said back-up die, in response to the extrusion of said tubular member thereinto, moves away from said extrusion die and increases the size of said variable-sized die cavity.

Claim 11

Apparatus for forming a flange on a tubular member which comprises: a pressure cylinder having a pressure chamber formed therein for receiving fluid; an extrusion die for receiving successive portions of said tubular member and being provided with a centrally formed bore of a configuration substantially complementary to the exterior of said tubular member; the entrance end of said extrusion die bore being slightly smaller than the exterior of said tubular member; a mandrel positioned within said pressure chamber and insertable into said tubular member to provide internal support therefor; the exterior of said mandrel being of a configuration substantially complementary to the interior of said tubular member and said mandrel being extendable through the extrusion die bore; a back-up die positioned opposite said extrusion die and movable away therefrom; an annular member encircling said back-up die and forming, in conjunction with said extrusion die and said back-up die, a variable-sized die cavity of a predeterminable ultimate size and shape substantially complementary to the size and shape of the flange to be formed on said tubular member; a piston extendable into said pressure chamber for increasing the pressure in said fluid sufficiently such that said mandrel suppoRted tubular member is forced through said extrusion die and into engagement with said back-up die to flare outwardly said tubular member into said die cavity; said piston also for increasing the pressure in said fluid sufficiently such that said fluid pressure, in cooperation with said back-up die, (i) applies hydrostatic pressure on said tubular member, including said flared portion, sufficiently high such that said tubular member, including said flared portion, is in a state of increased deformability, and (ii) forces successively portions of said tubular member, in said state, through said extrusion die and into said variable-sized die cavity; and said back-up die, in response to the extrusion of said tubular member thereinto, moves away from said extrusion die and increases the size of said variable-sized die cavity.

Claim 12

Apparatus for hydrostatically extruding a flange on an end of a metal tube, which comprises: a mandrel insertable into said metal tube and for providing internal support to said metal tube; a pressure vessel having a pressure chamber formed therein for receiving fluid and said mandrel supported metal tube; an extrusion die positioned at one end of said pressure chamber and being provided with a centrally formed die orifice of a configuration substantially complementary to the outer cross-sectional dimension of said metal tube and for permitting the forced passage therethrough of said mandrel supported metal tube; said extrusion die also including portions defining partially a die cavity; a back-up die positioned opposite said extrusion die and including a die surface for defining partially said die cavity and for engagement by said end of said metal tube to flare said end outwardly into said cavity; said back-up die having a centrally located, substantially frusto-conical shaped bore formed therein for receiving said mandrel upon the passage of said mandrel through said die orifice and said die cavity; said back-up die being mounted for movement away from said extrusion die to provide for an increase in the size of said cavity; an annular member closely surrounding one end of said back-up die and for defining the balance of said die cavity; said annular member being mounted for lateral movement to accommodate for varying wall thickness in said metal tube and for maintaining said mandrel in substantially central location of said bore formed in said back-up die; and a piston insertable into said pressure chamber and for raising the pressure of said fluid to a level sufficiently high to (i) apply, in cooperation with said back-up die, hydrostatic pressure on said metal tube such that said metal tube is in a state of increased deformability, and (ii) force said mandrel supported metal tube through said die orifice to extrude portions of said metal tube into said die cavity, whereupon said back-up die (i) moves away from said extrusion die to increase the size of said die cavity, and (ii) maintains said extruded portions of said metal tube in close confinement so as to maintain, in cooperation with said fluid pressure, said metal tube in said state.

Claim 13

Apparatus for hydrostatically extruding a flange on an end of a metal tube, which comprises: a mandrel insertable into said metal tube and for providing internal support to said metal tube; a pressure vessel having a pressure chamber formed therein for receiving fluid and said mandrel supported metal tube; an extrusion die positioned at one end of said pressure chamber and being provided with a centrally formed die orifice of a configuration substantially complementary to the outer cross-sectional dimension of said metal tube and for permitting the forced passage therethrough of said mandrel supported metal tube; said extrusion die also including portions defining partially a die cavity; a back-up die positioned opposite said extrusion die and including a die surface for defining partially said die cavity and for engagement by said end of said metal tube to flare said end outwardly into said cavity; said back-up die having a centrally located, substantially frusto-conical shaped bore formed therein for receiving said mandrel upon the passage of said mandrel through said die orifice and said die cavity; said back-up die being mounted for movement away from said extrusion die to provide for an increase in the size of said cavity; an annular member closely surrounding one end of said back-up die and for defining the balance of said die cavity; said annular member being mounted for lateral movement to accommodate for varying wall thickness in said metal tube and for maintaining said mandrel in substantially central location of said bore formed in said back-up die; and a piston insertable into said pressure chamber and for raising the pressure of said fluid to a level sufficiently high to (i) apply, in cooperation with said back-up die, hydrostatic pressure on said metal tube such that said metal tube is in a state of increased deformability, and (ii) force said mandrel supported metal tube through said die orifice to extrude portions of said metal tube into said die cavity, whereupon said back-up die (i) moves away from said extrusion die to increase the size of said die cavity, and (ii) maintains said extruded portions of said metal tube in close confinement so as to maintain, in cooperation with said fluid pressure, said metal tube in said state.

Claim 14

Apparatus according to claim 8 wherein said back-up die is self-balancing and is comprised of: a ball member on which said die surface is formed and in which said bore is formed; a socket member which receives pivotably said ball member; and said ball member, upon the occurrence of an excessive extrusion of said portions of said metal tube into an area of said die cavity, being pivotable in the direction of said die cavity area and effective to move said mandrel, within said extrusion die orifice, in the direction of said excessive extrusion so as to reduce the distance between said mandrel and said extrusion die orifice in the direction of said excessive extrusion and retard the extrusion of said portions of said metal tube into said die cavity area.

Claim 15

Apparatus for extruding a flangE on a tubular member, which comprises: low friction means for engageably receiving said tubular member; forcing means for receiving said low friction means and for forcing said low friction means into high pressure, low friction engagement with said tubular member; high friction means insertable within said tubular member; an extrusion die having an orifice formed therein; means defining a die cavity; means for operating said forcing means; and means for operating said high friction means to pull frictionally said tubular member through said die orifice and extrude portions of said tubular member into said die cavity to form said flange.

Claim 16

Apparatus for extruding a flangE on a tubular member, which comprises: low friction means for engageably receiving said tubular member; forcing means for receiving said low friction means and for forcing said low friction means into high pressure, low friction engagement with said tubular member; high friction means insertable within said tubular member; an extrusion die having an orifice formed therein; means defining a die cavity; means for operating said forcing means; and means for operating said high friction means to pull frictionally said tubular member through said die orifice and extrude portions of said tubular member into said die cavity to form said flange.

Claim 17

Apparatus according to claim 10, wherein said low friction means, and said forcing means, are of such complementary configuration so as to develop a low friction, high pressure gradient between the low friction means and the tubular member.

Claim 18

Apparatus for extruding a flange on a tubular member, which comprises: a mandrel insertable within said tubular member and for supporting the interior of said tubular member; a low friction, pressure sleeve for encircling slidably said tubular member; a forcing member engageable with said low friction pressure sleeve and for forcing said sleeve into pressed, low friction contact with said tubular member; the exterior surface of said mandrel being such that the friction between said surface and the interior of said tubular member is greater than the friction between the exterior of the tubular member and said low friction, pressure sleeve; an extrusion die having an extrusion die orifice formed therein for permitting the forced passage therethrough of said mandrel supported tubular member; means defining an extrusion die cavity; means for forcing said forcing member into engagement with said pressure sleeve to establish said pressed, low friction contact between said sleeve and said tubular member; and means for forcing said mandrel, in said frictional contact with said tubular member, through said die orifice to pull frictionally said tubular member through said die orifice and extrude end portions thereof into said die cavity and form said flange.

Claim 19

Apparatus for extruding a flange on a tubular member, which comprises: a mandrel insertable within said tubular member and for supporting the interior of said tubular member; a low friction, pressure sleeve for encircling slidably said tubular member; a forcing member engageable with said low friction pressure sleeve and for forcing said sleeve into pressed, low friction contact with said tubular member; the exterior surface of said mandrel being such that the friction between said surface and the interior of said tubular member is greater than the friction between the exterior of the tubular member and said low friction, pressure sleeve; an extrusion die having an extrusion die orifice formed therein for permitting the forced passage therethrough of said mandrel supported tubular member; means defining an extrusion die cavity; means for forcing said forcing member into engagement with said pressure sleeve to establish said pressed, low friction contact between said sleeve and said tubular member; and means for forcing said mandrel, in said frictional contact with said tubular member, through said die orifice to pull frictionally said tubular member through said die orifice and extrude end portions thereof into said die cavity and form said flange.

Claim 20

Apparatus according to claim 13 wherein said low friction pressure sleeve and said forcing member are of complementary tapering configuration such that a pressure gradient is developed along the successive lengths of the tubular member encircled by said pressure sleeve, said pressure gradient being developed increasingly along said encircled length of tubular member as said pressure sleeve increases in width of taper.

Claim 21

Apparatus for forming a flange on an end of a tubular member, which comprises: a mandrel insertable within said tubular member and for supporting the interior of said tubular member; a low friction, pressure sleeve for encircling slidably said tubular member; a forcing member engageable with said low friction, pressure sleeve and for forming said sleeve into pressed low friction contact with said tubular member; the exterior surface of said mandrel being such that the friction between said surface and the interior of said tubular member is greater than the friction between the exterior of the tubular member and said low friction, pressure sleeve; an extrusion die having an extrusion die orifice formed therein for permitting the forced passage therethrough of said mandrel supported tubular member; a back-up die; means defining an expandable extrusion die cavity cooperatively with said extrusion die and said back-up die; said mandrel for pulling frictionally said tubular member through said extrusion die orifice into said expandable die cavity; said mandrel and said back-up die for cooperatively building up hydrostatic pressure in said tubular member sufficiently high so as to place said member in a plastic state and cause the extrusion of portions of said tubular member into said expandable die Cavity; and said back-up die being movable in response to said extrusion into said expandable die cavity to provide for an increase in the size of said die cavity and accommodate said portions of said tubular member extruded into said die cavity to form said flange.

Claim 22

Apparatus for forming a flange on an end of a tubular member, which comprises: a mandrel insertable within said tubular member and for supporting the interior of said tubular member; a low friction, pressure sleeve for encircling slidably said tubular member; a forcing member engageable with said low friction, pressure sleeve and for forming said sleeve into pressed low friction contact with said tubular member; the exterior surface of said mandrel being such that the friction between said surface and the interior of said tubular member is greater than the friction between the exterior of the tubular member and said low friction, pressure sleeve; an extrusion die having an extrusion die orifice formed therein for permitting the forced passage therethrough of said mandrel supported tubular member; a back-up die; means defining an expandable extrusion die cavity cooperatively with said extrusion die and said back-up die; said mandrel for pulling frictionally said tubular member through said extrusion die orifice into said expandable die cavity; said mandrel and said back-up die for cooperatively building up hydrostatic pressure in said tubular member sufficiently high so as to place said member in a plastic state and cause the extrusion of portions of said tubular member into said expandable die Cavity; and said back-up die being movable in response to said extrusion into said expandable die cavity to provide for an increase in the size of said die cavity and accommodate said portions of said tubular member extruded into said die cavity to form said flange.

Claim 25

The friction extrusion method of forming a flange on a deformable tubular member, which comprises the steps of: inserting a high friction mandrel into said tubular member; surrounding said tubular member with a low friction, high pressure sleeve; mechanically flaring the end of said tubular member; mechanically pressurizing said tubular member (including the flared end) to a degree sufficiently high so as to place said tubular member (including said flared end) in a state of increased deformability, by forcing said sleeve into low friction, high pressure engagement with said tubular member and by frictionally moving said tubular member with said mandrel through an extrusion die and into an expandable die cavity and into engagement with a back-up die; and maintaining said tubular member, including said flared portion, in said state of increased deformability by the cooperative mechanical pressure applied by said sleeve, said mandrel and said back-up die, while moving successive portions of said tubular member through said extrusion die and into said expandable die cavity to cause the portion of said tubular member confined in said die cavity to increase in thickness beyond said initial thickness and form a flange on said tubular member.

Claim 26

The friction extrusion method of forming a flange on a deformable tubular member, which comprises the steps of: inserting a high friction mandrel into said tubular member; surrounding said tubular member with a low friction, high pressure sleeve; mechanically flaring the end of said tubular member; mechanically pressurizing said tubular member (including the flared end) to a degree sufficiently high so as to place said tubular member (including said flared end) in a state of increased deformability, by forcing said sleeve into low friction, high pressure engagement with said tubular member and by frictionally moving said tubular member with said mandrel through an extrusion die and into an expandable die cavity and into engagement with a back-up die; and maintaining said tubular member, including said flared portion, in said state of increased deformability by the cooperative mechanical pressure applied by said sleeve, said mandrel and said back-up die, while moving successive portions of said tubular member through said extrusion die and into said expandable die cavity to cause the portion of said tubular member confined in said die cavity to increase in thickness beyond said initial thickness and form a flange on said tubular member.

Claim 27

The friction extrusion method of forming a flange on an end of a tubular member, which comprises the steps of: inserting a high friction mandrel into said tubular member; surrounding said tubular member with a low friction, high pressure sleeve; flaring the end of said tubular member; forcing said sleeve into low friction, high pressure engagement with said tubular member; and while maintaining said sleeve in low friction, high pressure engagement with said tubular member, frictionally forcing portions of said tubular member with said mandrel through an extrusion die and into a die cavity to form a flange on said tubular member.

Claim 28

The friction extrusion method of forming a flange on an end of a tubular member, which comprises the steps of: inserting a high friction mandrel into said tubular member; surrounding said tubular member with a low friction, high pressure sleeve; flaring the end of said tubular member; forcing said sleeve into low friction, high pressure engagement with said tubular member; and while maintaining said sleeve in low friction, high pressure engagement with said tubular member, frictionally forcing portions of said tubular member with said mandrel through an extrusion die and into a die cavity to form a flange on said tubular member.

Claim 29

Method of deforming a workpiece against a die surface, which comprises: positioning the workpiece between a high pressure, low friction, solid member; and a high pressure, high friction drive member; pressurizing said solid member to apply a normal pressure to the workpiece to force the workpiece into high pressure, high friction engagement with said drive member, and to apply a predetermined pressure gradient along the workpiece; and advancing said drive member to cause said member to frictionally transport said workpiece into engagement with said die surface with sufficient force to: (i) produce an axial stress in said workpiece sufficiently great to place said workpiece in a plastic state, and (ii) to deform said workpiece while in said plastic state; said normal pressure and said axial stress not departing from each other at any point along the workpiece by an amount greater than the yield strength of the workpiece.

Claim 30

Method of deforming a workpiece against a die surface, which comprises: positioning the workpiece between a high pressure, low friction, solid member; and a high pressure, high friction drive member; pressurizing said solid member to apply a normal pressure to the workpiece to force the workpiece into high pressure, high friction engagement with said drive member, and to apply a predetermined pressure gradient along the workpiece; and advancing said drive member to cause said member to frictionally transport said workpiece into engagement with said die surface with sufficient force to: (i) produce an axial stress in said workpiece sufficiently great to place said workpiece in a plastic state, and (ii) to deform said workpiece while in said plastic state; said normal pressure and said axial stress not departing from each other at any point along the workpiece by an amount greater than the yield strength of the workpiece.