Impact hydraulic forming equipment

Claim 2

Equipment for forming a tubular member to predetermined shape by impact hydraulic pressure comprising, in combination, a relatively elongated tubular guide; a pair of initially axially spaced annular piston dies slidably mounted in said guide and engaging the axially opposite end of the member to be formed to compress that portion of the member between said piston dies axially responsive to hydraulic pressure applied to axially outer faces of said piston dies, plurality initially axially spaced annular forming dies slidably displaceable in said guide and embracing the member intermediate said piston dies; channel means operatively associated with said guide and connected to the hydraulic chamber of a generator of impact hydraulic pressure, and operable to fill hydraulic fluid into the tubular member and into pressure chambers defined by the axially outer faces of said dies; said channel means, upon impact operation of a generator of impact hydraulic pressure connected thereto, applying a sudden impact hydraulic pressure simultaneously to the interior of the member, to expand the same laterally, to said pressure chambers, to move said dies axially toward each other to compress the member axially, and to all of said dies to move the same axially toward each other to limit lateral expansion of the member to said predetermined shape; and throttling passages in at least some of said dies communicating with said channel means and brought progressively into communication with at least some of said pressure chambers responsive to diE movement to control the application of axial pressure to the tubular member in accordance with a lateral deformation of the tubular member by the internal pressure therein.

Claim 3

Equipment for forming a tubular member to a prdetermined shape by impact hydraulic pressure, as claimed in claim 1, in which said piston dies and said forming dies are telescoped with each other within said tubular guide; each forming die comprising a respective piston having a pressure chamber adjacent its axially outer end and a radially inwardly projecting forming die at its axially inner end; said piston dies being initially subjected to the impact hydraulic pressure in said channel means to compress the tubular member axially; said pressure chambers of said forming dies being successively brought into communication with said channel means, responsive to the initial movement of said piston dies, beginning with the forming dies whose axially inner ends are nearest to the center of said guide and ending with the pressure chambers of those forming dies which are furthest from the center midpoint of said guide.

Claim 4

Equipment for forming a tubular member to a predetermined shape by impact hydraulic pressure, as claimed in claim 1, including a pair of opposed tubular cross-section forming dies having respective pressure chambers at their axially outer ends; a pair of forming die pistons each secured to a respective forming die for movement therewith as a unit and each having a respective pressure chamber at its axially outer end; each forming die piston having a reduced diameter portion extending coaxially into the associated forming die and defining therewith an annular space receiving a respective end of the tubular member to be formed; said annular piston dies each being slidably mounted on the reduced cross-section extension of the associated forming die piston and in sliding engagement with the associating forming die; each piston die being formed with abutment surfaces engageable with mating abutment surfaces on the associated forming die and on the reduced cross-section extension of the associated forming die piston, and having a step formation for engagement with the adjacent end of the tubular member to be formed; each forming die piston being formed with throttle passages extending therethrough and connecting the pressure chamber of the associated annular piston die to said channel means whereby, upon operation of the impact hydraulic pressure generator, the impact hydraulic pressure is applied to the pressure chambers of said annular piston dies to move said annular piston dies toward each other to compress the tubular member axially; the impact hydraulic pressure also being applied to the interior of the tubular member through said tubular forming die pistons; said annular piston dies abutting said forming dies to move said forming dies toward each other together with the associated forming die pistons; each forming die piston having throttling passages therein uncovered by movement of the associated annular piston die to connect the pressure chambers of said forming dies to said channel means for continued movement of said forming dies toward each other responsive to the impact hydraulic pressure; said guide being formed with throttling passages communicating with said channel means and uncovered by movement of said forming die pistons toward each other to establish communication between said channel means and the pressure chambers of said forming die pistons for application of the impact hydraulic pressure to the axially outer ends of said forming die pistons to move said forming dies into abutment with each other to complete deformation of the tubular member.

Claim 5

Equipment for forming a tubular member to a predetermined shape by impact hydraulic pressure, as claimed in claim 1, for forming tubular members having a large magnitude length to diameter ratio, including a pair of forming dies each secured to a respective annular piston die for movement as a unit therewith; each piston Die having an axially outwardly projecting tubular extension slidably engaged in a respective guide portion of said die; each guide portion being formed with throttling passages connecting said channel means to the pressure chamber of the associated piston die; the tubular extension of each piston die being formed with a plurality of radial ports therethrough initially closed by the associated guide portion; each piston die having the elongated tubular member extending therethrough in fluid-tight relation and projecting axially upwardly beyond the respective tubular extension; respective annular collars each engageable with a respective axially opposite end of the tubular member within said channel means; and rods connecting each annular collar to the associated piston die; whereby, upon operation of the impact hydraulic pressure generator, the impact hydraulic pressure is initially supplied through the passages in said guide portions to the pressure chambers of the associated piston dies to move said forming dies toward each other, the impact hydraulic pressure also being applied to the interior of the tubular member through said annular collars from said channel means; said radial ports in said piston dies being successively connected to the associated pressure chambers responsive to axial inward movement of the associated piston die to progressively increase the cross-section for application of the impact hydraulic pressure in said channel means through said pressure chambers.