Extrusion press for extruding tubes
AssigneeSchloemann-Siemag Aktiengesellschaft
InventorsHorst H. Groos, Urban Richardt, Siegfried Hoffmeier
Life of this patent
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Abstract
In tube extrusion presses, there are two steps in production. Firstly, a mandrel pierces a hole through the center of a billet, the tip of the mandrel ending up just within the opening of the extrusion die. Secondly, the now hollow cylindrical billet is extruded through the die and over and around the tip of the mandrel to produce a tube. To limit the movement of the mandrel, stroke-limiting rods are provided which pass through bores in a part attached to the mandrel and in a fixed part of the press. The rods can be held fast in one or both of these bores, or released to slide through them, depending on the stage reached in the extrusion process.
Claims10
An extrusion press for extruding tubes, the press including a counter platen, an extrusion die mounted on said counter platen, a cylinder cross-head, tension columns joining the counter platen and the cylinder cross-head, a movable cross-head able to be moved between the counter platen and cylinder cross-head, a billet container movable between the counter platen and the cylinder cross-head and a press stem carried by the movable cross-head for movement therewith to extrude a billet in the container through the die, the press also including a piercing device carried by the movable cross-head, which device comprises a piercing mandrel, a piston and cylinder arrangement for driving said piercing mandrel relative to the movable cross-head, a piercing cross-bar fixed to said piercing mandrel, and axially movable mandrel stroke-limiting rods arranged parallel to the direction of movement of the movable cross-head and the mandrel, each rod being received in a bore in the piercing cross-bar and in a bore in the cylinder cross head, fluid pressure operated releasable clamping means being provided in each of the bores to releasably clamp the stroke-limiting rods and means for selectively applying fluid pressure to said clamping means in the bores of said piercing cross-bar and to said clamping means in the bores of said cylinder cross-head respectively.
Dependencies are inferred from the claim text.