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EP-4504435-B1 - EXTRUSION PRESS, IN PARTICULAR A SHORT STROKE EXTRUSION PRESS, FOR PRODUCING METAL EXTRUDATES BY EXTRUDING A BILLET

EP4504435B1EP 4504435 B1EP4504435 B1EP 4504435B1EP-4504435-B1

Inventors

  • GALLI, Alessandro Mario
  • MERLINI, Mattia
  • BRACESCO, Dario

Dates

Publication Date
20260506
Application Date
20230328

Claims (15)

  1. An extrusion press for producing metal extrudates by extruding a billet (27), the extrusion press comprising: - a punch holder crosspiece (20) which carries a punch (21) and is adapted to be translated in two opposite senses of translation along a first extrusion direction (X); - a billet holder loader (24) adapted to be alternately positioned between a resting position and a loading position, the loading position in particular being a position wherein the billet (27) is arranged on the billet holder loader (24) along the first extrusion direction (X); wherein said punch holder crosspiece (20) is translatable along a second direction (Y), perpendicular to said first extrusion direction (X), between a first position thereof and a second position thereof; wherein when the billet holder loader (24) is in said resting position and said punch holder crosspiece (20) is in the first position thereof, the translation of the punch holder crosspiece (20) along said first extrusion direction (X) in a first sense of translation, or sense of extrusion, causes a push by said punch (21) against said billet (27) and the extrusion of said billet (27); wherein said extrusion press comprises restraining means (40, 41) adapted to mutually restrain said punch holder crosspiece (20) and said billet holder loader (24); wherein when the punch holder crosspiece (20) is in the first position, it is restrained to the billet holder loader (24) by means of said restraining means (40, 41) so that the translation of said punch holder crosspiece (20) from the first position to the second position causes the movement of the billet holder loader (24) from said resting position to said loading position; characterized in that when said billet holder loader (24) is in said resting position, the translation of said punch holder crosspiece (20) along said first extrusion direction (X) in said sense of extrusion, in particular to extrude the billet (27), causes the mutual release of said punch holder crosspiece (20) and said billet holder loader (24).
  2. A press according to claim 1, wherein the punch holder crosspiece (20) can take on a third position wherein the punch (21) is at least partially inserted into a container (22) adapted to at least partially contain said billet (27) during the extrusion of said billet (27); and wherein by passing from the first position to the third position, the punch holder crosspiece (20) is released from the billet holder loader (24).
  3. A press according to claim 1 or 2, configured so that the billet holder loader (24) moves from the resting position to the loading position by being dragged by the punch holder crosspiece (20) which moves from the first position thereof to the second position thereof.
  4. A press according to any one of the preceding claims, wherein when the punch holder crosspiece (20) is in the second position, it is restrained to the billet holder loader (24) by means of said restraining means (40, 41) so that the translation of said punch holder crosspiece (20) from the second position to first position causes the movement of the billet holder loader (24) from said loading position to said resting position; the extrusion press in particular being configured so that the billet holder loader (24) moves from the loading position to the resting position by being pushed by the punch holder crosspiece (20) which moves from the second position thereof to the first position thereof.
  5. A press according to any one of the preceding claims, configured so that when said billet holder loader (24) is in said resting position, a translation of said punch holder crosspiece (20) along said first extrusion direction (X) in sense opposite to said sense of extrusion causes the mutual restraint of said punch holder crosspiece (20) and said billet holder loader (24).
  6. A press according to any one of the preceding claims, comprising a container (22) adapted to at least partially contain said billet (27) during the extrusion of said billet (27); in particular wherein the press is configured so that when the punch (21) is outside the container (22), the punch holder crosspiece (20) and the billet holder loader (24) are restrained to each other by means of said restraining means (40, 41).
  7. A press according to any one of the preceding claims, wherein, in particular in use, said punch holder crosspiece (20) and said billet holder loader (24) are restrainable to each other by means of said restraining means (40, 41) and are releasable from each other according to the position along the extrusion direction (X) of the punch holder crosspiece (20).
  8. A press according to any one of claims 1 to 7, wherein said restraining means (40, 41) comprise a first restraining element (40) which is integral with said punch holder crosspiece (20), and a second restraining element (41) which is integral with said billet holder loader (24).
  9. A press according to claim 8, wherein said restraining means (40, 41) are configured, in use, to restrain and release said punch holder crosspiece (20) and said billet holder loader (24) to/from each other when the punch holder crosspiece (20) is translated along the extrusion direction (X).
  10. A press according to claim 8 or 9, wherein said first restraining element (40) comprises a first surface (42) and second surface (45) distinct from each other, and the second restraining element (41) comprises a first surface (43) and second surface (46) distinct from each other, the first surface (42) of the first restraining element (40) facing the first surface (43) of the second restraining element (41), and the second surface (45) of the first restraining element (40) facing the second surface (46) of the second restraining element (41) when the first restraining element (40) and the second restraining element (41) are restrained to each other.
  11. A press according to any one of claims 8 to 10, wherein said first restraining element (40) is a hook or is hook-shaped, and said second restraining element is a tooth.
  12. An extrusion plant for producing metal extrudates by extruding a billet (27), comprising an extrusion press according to any one of the preceding claims.
  13. An extrusion method for producing metal extrudates by extruding a billet (27) by means of an extrusion press according to one of claims 1 to 11, wherein there is provided a step in which the punch holder crosspiece (20) is translated from the first position to the second position, and wherein the translation of said punch holder crosspiece (20) from the first position to the second position causes the movement of the billet holder loader (24) from said resting position to said loading position; in particular, wherein the billet holder loader (24) is moved from the resting position to the loading position by being dragged by the punch holder crosspiece (20) which moves from the first position thereof to the second position thereof; wherein there is provided a step in which the punch holder crosspiece (20) and the billet holder loader (24) are released from each other by translating the punch holder crosspiece (20) along said first extrusion direction (X) in the sense of extrusion.
  14. A method according to claim 13, wherein there is provided a step in which the punch holder crosspiece (20) is translated from the second position to the first position, and wherein the translation of said punch holder crosspiece (20) from the second position to the first position causes the movement of the billet holder loader (24) from said loading position to said resting position; in particular wherein the billet holder loader (24) moves from the loading position to the resting position by being pushed by the punch holder crosspiece (20) which moves from the second position thereof to the first position thereof.
  15. A method according to claim 13 or 14, wherein there is provided a mutual restraining step between the billet holder loader (24) and the punch holder crosspiece (20) by means of said restraining means (40, 41); in particular wherein said restraining step provides the translation of the punch holder crosspiece (20) along said first extrusion direction (X) in sense opposite to the sense of extrusion.

Description

Field of the invention The present invention relates to the field of the iron and steel industry. The present invention in particular relates to the field of producing metal products by extruding a billet. In particular, the present invention relates to an extrusion press. Background art In an extrusion press of the type diagrammatically shown in Figure 1, the billet (e) may be loaded in different ways. In particular, the billet (e) may be loaded between the extrusion die (b) and the container (d) (front loading); or the billet may be loaded behind the container (d) (rear loading). Rear loading presses are divided into two groups: long stroke, in which the billet is loaded between the extrusion punch (g) and the container (d); and short stroke, where the punch (g), by means of the automation thereof, is translated laterally (in direction orthogonal to the extrusion axis) and the billet (e) is loaded in the space left free by the lateral translation of the punch (g). For the loading operations of the billet (e), the billet (e) is first positioned on a billet loader comprising a cradle-shaped portion adapted to receive the billet oriented parallel to the extrusion axis (with the longitudinal extension axis parallel to the extrusion axis). Thereby, the billet (e) is positioned laterally with respect to the press, in particular with respect to the space in which the advancing movements of the punch (during the extrusion step) and the retracting movements of the punch itself (at the end of the extrusion step) take place. Therefore, the loading of the billet (e) may be summarized as follows. At the end of the actual extrusion step, with the punch (g) positioned outside the container (d), and therefore free, the punch (g) is translated (by translating the relative punch holder crosspiece) perpendicularly with respect to the extrusion direction and positioned laterally with respect to the main body of the press, whereby the punch is no longer along the extrusion direction. Then, the billet holder loader is translated perpendicularly with respect to the extrusion direction, positioning the billet along the extrusion direction so as to be inserted into the container (d). In particular, the billet is positioned in the middle of the press. During the successive step, the billet (e) is inserted into the container (d) by means of thrust means which are part of the billet holder loader. The billet holder loader is then retracted and brought back to the starting position, laterally with respect to the press body. Lastly, the punch (g) is brought back to the preceding position, aligned with the extrusion direction, in a position adapted to the successive extrusion step. The extrusion presses according to the known art with the billet loading methods summarized above have various disadvantages and/or drawbacks which the Applicant intends to overcome or at least minimize by means of the present invention. First, it should be considered that the transfer of the billet from the starting position, which is lateral with respect to the press body, is obtained by means of a dedicated actuator. The actuator belongs to the billet holder loader. The actuator is hydraulic and/or electric and/or pneumatic. The actuator in particular is adapted to reposition the billet holder loader in the middle of the press (according to the methods described above). The presence of a dedicated actuator causes different problems, such as, for example, the need to prepare a dedicated actuation (hydraulic or electric or pneumatic, for example), with subsequent increases in press production costs, which often are incompatible with the needs of the market; and/or the need to plan and implement regular maintenance operations, and dedicated also in this case, and therefore again with subsequent increase in the press management costs. Moreover, the risks of accidental interference of the movable press components (the punch holder crosspiece and loader of the billet in particular) are to be considered, for example in the event of erroneous synchronism between the respective movements, with the risk of also serious damage to said movable components, and therefore lengthy machine downtime and lengthy and costly repair operations. Documents IT9022217A1 and WO99/54067A1 disclose extrusion presses configured so that the punch holder crosspiece and the billet holder loader always move together, in particular also, disadvantageously, when the punch holder crosspiece translates along the extrusion direction in the sense of extrusion. Objects of the present invention Thus, it is an object of the present invention to provide an extrusion press, in particular of the short stroke type, which allows the disadvantages and/or drawbacks encountered in the extrusion presses of the prior art to be overcome or at least reduced. In particular, it is an object of the present invention to provide an extrusion press which does not provide the use of dedicated actuators for loading t