EP1850980B1 - Extrusion press - Google Patents

Description

The invention relates to an extrusion spinning press. More particularly, the invention relates to a fixed crossbar for such a press.

• un sommier avant fixe ;
• une traverse arrière également fixe ;
• des colonnes ou tirants destinés à maintenir une distance constante entre la traverse fixe et le sommier ;
• une filière, dont l'axe définit l'axe de filage, prenant appui sur le sommier ;
• un conteneur placé entre la traverse fixe et le sommier et muni d'un logement centré sur l'axe de filage, ayant un diamètre et une longueur correspondant au diamètre et à la longueur d'une billette à filer enfilée dans ce logement, le conteneur ayant une face avant tournée vers le sommier et une face arrière tournée vers la traverse fixe,
• un vérin principal de filage, ayant un corps de vérin prenant appui sur la traverse fixe et un piston déterminant l'extrusion par la filière du métal de la billette comprimée par enfilement d'un fouloir dans le logement du conteneur.

It is known that an extrusion spinning machine usually comprises along a spinning axis:

• a fixed front bed base;
• a rear crossbar also fixed;
• columns or tie rods intended to maintain a constant distance between the fixed beam and the bed base;
• a die, the axis of which defines the spinning axis, resting on the bed base;
• a container placed between the fixed crossbar and the bed base and provided with a housing centered on the spinning axis, having a diameter and a length corresponding to the diameter and the length of a spinning billet slipped into this housing, the container having a front face facing the bed base and a rear face facing the fixed beam,
• a main spinning jack, having a cylinder body bearing on the fixed crossbar and a piston determining the extrusion by the die of the billet metal compressed by threading a follower in the housing of the container.

Usually, the piston of the main cylinder is supported on a movable crosshead moving between the bed base and the fixed beam.

In the so-called direct method, the container is fixed and is supported, by a front face, on the die carried by the bed frame, and the follower is mounted on the movable cross member so as to penetrate into the housing, under the action of the jack main.

In the so-called reverse method, the die is mounted at the end of a fixed tubular follower bearing on the bed base, and the container is supported by its rear face on the movable cross member so that the housing is threaded on the follower tubular by causing the extrusion of the metal by the die.

In general, the fixed crosspiece of a spinning press is a support for the body of the main spinning jack which, by advancing the piston, determines the extrusion of the metal by the die carried by the bed. This cross therefore tends to move away from the bed base and must be maintained at a constant distance from it by tie rods which are often prestressed.

On the other hand, the piston of the main cylinder is supported on a movable cross member which carries the follower in the direct spinning and pushes the container in the reverse spinning. This movable cross member must be able to be moved independently between the bed base and the fixed crossbar for the various maneuvers, for example loading the billet. To avoid using, for this purpose, the main cylinder, the movable crosshead is actuated by at least two auxiliary cylinders bearing on the fixed crossbar.

Similarly, the container can be moved by means of auxiliary cylinders also bearing on the fixed crossbar.

The fixed crossbar thus forms a transverse beam, connected to the bed frame by tie rods and having a central support portion of the main cylinder and the lateral support portions of the tie rods and auxiliary cylinders maneuvering the movable cross member and the container.

Until now such a beam was made in welded construction and included, as shown by way of example on Figures 1 and 2 , two flanges apart, perpendicular to the axis of spinning and connected by plates or angles to present the strength required to cash the extrusion forces.

Usually, the body of the main cylinder forms a cylindrical yoke closed by a bottom and threaded into two circular orifices centered on the spinning axis and arranged on the two front and rear flanges of the fixed crossbar, the front portion of the cylinder head being supported on the front flange by an outer flange-shaped flange.

On the other hand, the two flanges are provided with holes aligned in pairs and distributed around the cylinder head, in which are threaded the ends of the tie rods and the auxiliary cylinders.

To obtain the desired productivity, the extrusion operations controlled by the main cylinder follow one another at a sufficient rate high and after spinning a billet, the movable cross member must be moved between the bed and the fixed cross by means of auxiliary actuating cylinders so as to allow the loading of the next billet.

Similarly, during each period, the container is moved by means of the auxiliary jacks maneuvering the container. After loading a new billet, the main cylinder is actuated to control the extrusion of the metal. As a result, during a cycle, the fixed beam is subjected to alternating stresses varying in intensity and frequency. The welded structure is therefore subjected to a severe test and its service life is reduced. This can result in the appearance of cracks in the welds connecting the constituent elements of the fixed transom. When these cracks become too large, they can be detected and repaired temporarily, but this requires the shutdown of the installation. In addition, premature aging of the fixed beam may present safety risks.

The invention therefore aims to solve the problems mentioned above by proposing a spinning press having a fixed crossbar having increased resistance to high speeds, and therefore a longer life. Another object of the invention is to propose a spinning press comprising a simplified implementation fixed cross member allowing rapid assembly and disassembly of the spinning press. The invention also aims to provide an alternative to existing fixed sleepers by providing a fixed cross which is more compact.

• une filière centrée sur un axe de filage et prenant appui sur un sommier,
• un vérin principal de filage comportant un corps tubulaire fermé par un fond du côté opposé à la filière et limitant une chambre cylindrique centrée sur l'axe de filage et dans laquelle coulisse un piston d'extrusion,
• une traverse fixe écartée axialement du sommier et sur laquelle prend appui le corps du vérin principal,
• un conteneur placé entre le sommier et la traverse fixe et limitant un logement pour une billette de métal à filer par extrusion dans la filière sous faction du vérin principal,
• au moins deux tirants fixés à leurs extrémités, respectivement sur le sommier et sur la traverse fixe pour le maintien entre ces derniers d'une distance constante.

The invention therefore applies to an extrusion press comprising, in general:

• a die centered on a spinning axis and resting on a bed base,
• a main spinning jack comprising a tubular body closed by a bottom on the side opposite the die and limiting a cylindrical chamber centered on the spinning axis and in which slides an extrusion piston,
• a fixed cross member spaced axially from the bed base and on which bears the body of the main cylinder,
• a container placed between the bed base and the fixed cross member and limiting a housing for a billet of metal extrusion spinning in the die under the main actuator,
• at least two tie rods fixed at their ends, respectively on the bed base and on the fixed crosspiece for the maintenance between them a constant distance.

According to the invention, the fixed cross member is constituted by a single solid piece made by forging and comprising a central part forming the body of the main jack, in which is formed a central bore made by internal machining of a central orifice. obtained during the forging and forming the chamber of said jack, and at least two extensions in the form of ears extending outwardly from the central portion and each traversed by a passage duct of a fixing end of the tie rod corresponding holding, extending between two spaced apart faces, respectively front and rear of said ear on which bears, in two opposite directions, said fixing end of the tie rod.

In a particularly advantageous embodiment, at least the bearing faces placed on the same side, respectively front or rear, ears, are placed in the same plane perpendicular to the spinning axis, so as to form together a face application of a fastening plate of the ends of the tie rods and comprising, on the one hand at each ear, a bearing portion of the corresponding tie rod and on the other hand, between two ears, at least a portion of support for at least one auxiliary actuator.

Preferably, the ears of the crosspiece extend over a length less than that of the central portion, so as to provide a front support face being set back from the front end of the central part and on which is supported the front fixing plate, the latter being provided with a central orifice in which the front end of the the central part of the massive crossing.

More preferably, the front end of the central portion of the solid crossbar is provided with an external counterbore having an annular bottom placed at the same level as the front bearing face and in which the front fixing plate is fitted with .

In the preferred embodiment, the front attachment plate is interposed between the front support face of each lug and a fixing member of the corresponding tie bearing on said lug, at least in the opposite direction of the extrusion direction.

Each holding tie rod is threaded into a hollow column extending between the bed base and the fixed cross member and is subjected to a prestressing tension by bearing on a rear face of the corresponding ear, said hollow column being supported in the opposite direction. inverse, on a front face of said ear, preferably via a plate for fixing at least one auxiliary actuating member.

Preferably, a movable crosshead is slidably mounted axially between the fixed crossmember and the bed base while resting on the container in the extrusion direction, and is actuated by at least two auxiliary actuating cylinders each having a body and a supporting rod. , respectively, on the massive crossbar and on the movable crosshead for the displacement of the latter, the body of each auxiliary actuating cylinder of the movable crosshead being fixed on a part of the front attachment plate between two ears of the massive crossbar .

Likewise, the press advantageously comprises at least two auxiliary jacks for maneuvering the container, each having a body and a rod bearing respectively on the fixed cross member and on the container, the body of each auxiliary actuating cylinder of the container being fixed on a part of the front attachment plate between two ears of the massive beam.

more preferably, the body of each auxiliary actuating cylinder comprises a front end fixed to the front attachment plate so as to bear thereon in the extrusion direction and in the opposite direction, and a bearing rear end on a rear fixing plate fixed on the back faces of the ears of the massive crossbar.

Preferably, the body of each auxiliary operating cylinder is threaded into at least one bore of the same diameter formed at least on the front attachment plate and has a shoulder bearing on said front fixing plate at least in the opposite direction to the direction extrusion.

Preferably, the body of the main cylinder comprises a cylindrical tubular portion consisting of the central portion of the massive crossbar surrounding the bore closing the cylinder chamber and a cup-shaped bottom, bent over the periphery of the bore, at a rear ends of the tubular part.

Preferably, the holding rods and the ears are centered in planes passing through the spinning axis and regularly distributed around it.

• La Figure 1 représente, en perspective et en coupe partielle, une traverse fixe selon l'art antérieur dans laquelle est logé un corps de vérin principal et deux vérins auxiliaires de manoeuvre ;
• La Figure 2 représente, en coupe transversale, la traverse fixe selon l'art antérieur de la Figure 1 ;
• La Figure 3A représente, en coupe axiale, une traverse fixe selon l'invention ;
• La Figure 3B représente, en vue de devant, la traverse fixe selon l'invention ;
• La Figure 4 représente, en perspective et en coupe partielle, la traverse fixe de la figure 3A portant une traverse mobile avec un vérin auxiliaire de manoeuvre ; et,
• La Figure 5 représente, en perspective, la traverse fixe de la figure 3A sur laquelle est fixée l'extrémité d'un tirant de maintien et une colonne creuse associée, un vérin auxiliaire de manoeuvre du conteneur et un vérin auxiliaire de manoeuvre de la traverse mobile portant la traverse mobile associée.

The invention will be better understood, and other objects, details, features and advantages thereof will become more clearly apparent from the following description of a particular embodiment of the invention, given solely for illustrative purposes and not limiting, with reference to the accompanying drawings. On these drawings:

• The Figure 1 represents, in perspective and in partial section, a fixed cross member according to the prior art in which is housed a main cylinder body and two auxiliary operating cylinders;
• The Figure 2 represents, in cross section, the fixed cross member according to the prior art of the Figure 1 ;
• The Figure 3A represents, in axial section, a fixed cross member according to the invention;
• The Figure 3B represents, in front view, the fixed cross member according to the invention;
• The Figure 4 represents, in perspective and in partial section, the fixed transom of the figure 3A carrying a movable crosshead with an auxiliary actuating jack; and,
• The Figure 5 represents, in perspective, the fixed transom of the figure 3A on which is fixed the end of a retaining tie rod and an associated hollow column, an auxiliary actuating cylinder of the container and an auxiliary actuating jack of the movable cross member carrying the associated movable cross member.

In what follows, the terms "before" and "back" make it possible to qualify the relative position of the elements along the spinning axis A oriented in the spinning direction, from the fixed crosspiece to the bed base via the die .

As mentioned above, Figures 1 and 2 represent, by way of example, a fixed cross member according to the prior art, forming a beam made of welded construction with two spaced flanges 10, 12 respectively limiting two circular orifices centered on the spinning axis A, which form the front and rear faces of a cylindrical housing in which is inserted the body 2 of the main spinning jack which bears, via a collar 20, on the front flange 10 of the fixed crossbar 1.

The Figures 1 and 2 show only the fixed crosshead and the body of the main cylinder, as well as two auxiliary cylinders. The other organs of the press can be of any known type and are not represented.

In the embodiment shown, the flanges 10 and 12 of substantially square shape are thick metal plates in which are respectively formed two axial bores 11 and 13. The inner diameter of these axial bores corresponds to the outer diameter of the cylinder body 2 to receive the latter. In addition, the flanges 10 and 12 respectively comprise peripheral bores which, preferably, are distributed symmetrically about the spinning axis A. On the figure 2 eight peripheral bores are shown. The flanges 10 and 12 respectively comprise a first series of four peripheral bores 18 and 18 'intended for receive one end of the holding tie rods extending between the fixed cross member 1 and the bed frame. Advantageously, these peripheral bores for tie rods 18 and 18 'are located in axial planes oriented at ± 45 ° with respect to the horizontal. Furthermore, the flanges 10 and 12 respectively comprise a second series of four peripheral bores 19 and 19 'intended to support auxiliary operating cylinders 70 and 80 ( figure 1 ), for moving respectively the movable crosshead or the container, forwards or back along the spinning axis A. The peripheral bores for auxiliary actuating cylinders 19 and 19 'are substantially placed in the middle of the sides of the flanges 10 and 12, in horizontal and vertical axial planes. The front end of the body of an auxiliary actuating cylinder is housed in one of the peripheral bores before 19 and fixed on the front flange 10, and its end is housed in the corresponding peripheral rear bore 19 'and fixed on the rear flange 12.

The flanges 10 and 12 are spaced perpendicular to the spinning axis A and held at a constant distance by a corresponding dimension structure forming a spacer. The figure 2 represents the fixed cross member 1 in cross section. The structure between the flanges 10 and 12 is constituted by a shell 14 and a plurality of plates or angles 16. The constituent elements of this structure are welded together, the structure is then itself welded to the flanges before 10 and rear 12. It It should be noted that the angles 16 of the structure are arranged so as to reinforce the fixed crossbar 1 at the places where the support forces of the tie rods and the jacks are applied and to give the beam thus constituted the inertia necessary to withstand the extrusion efforts. In particular, angles 16 are arranged between the two flanges 10, 12 to form with the outer surface of the shell 14 reinforcing boxes in which pass the ends of the tie rods 18 and 18 '.

As shown by Figures 3A and 3B , unlike the fixed crossbar of the prior art, made of welded construction, the fixed cross member according to the invention consists of a single solid piece monobloc.

This solid fixed crosspiece 100 comprises a central portion 102 in which is formed a main axial bore 101 whose axis coincides with the spinning axis A.

Thus, whereas, in the prior art, the fixed crossbar is a simple beam in which the body of the main cylinder is threaded, in the invention, it is the central portion 102 of the solid part 100 which constitutes itself the cylinder body whose piston slides in the bore 101 which thus constitutes the chamber 4 of the main cylinder. This chamber 4 is closed at the rear by a bottom 3 preferably consisting of a separate portion in the form of a bowl, welded around the periphery of the bore 101, at a rear end 103 of the central portion 102. .

In a known manner, this bottom 3 may be solid or provided with an axial bore 31 allowing the sliding passage of an extension rod towards the rear of the piston of the jack.

This solid fixed crosspiece 100 according to the invention also comprises at least two extensions in the form of lugs protruding radially outwardly relative to the central portion 102 tubular. In the preferred embodiment shown in the figures, the massive fixed beam 100 comprises four such ears 105 a-d. They are distributed symmetrically around the spinning axis A. For example, the ears 105 a-d are arranged in axial planes passing through the spinning axis A and inclined at ± 45 ° with respect to a horizontal plane.

The central portion 102 and the lugs 105 a-d of the solid cross member 100 are made in one piece by forging. The bore 101 of large diameter is made by internal machining of a central orifice obtained during the forging.

The tie rods for maintaining a constant distance between the solid fixed cross member 100 and the box spring (not shown) and the auxiliary actuating jacks of the container and the movable cross member bear in two opposite directions, towards the front and towards the rear, on the massive cross 100 which is both the cylinder body and the transverse support beam.

Each ear 105 ad has the function of respectively providing support at the end of an associated holding tie 60 ad ( figure 5 ), the other end of said tie bearing on the bed frame. Each lug 105 ad is traversed by a duct 106 ad associated cylindrical whose axis B ad is parallel to the axis of spinning A. Each duct 106 ad extends between a front bearing surface 107 ad and a bearing face rear 108 ad of the corresponding ear 105 ad. The conduits 106 ad have the function of forming a passage for the fixing end of the retaining tie rod 60 ad corresponding.

Advantageously, the different front bearing faces 107 ad are located in the same plane before P1 perpendicular to the spinning axis A. the front bearing faces 107 ad together define, on the solid fixed beam 100, a surface before application 111. Similarly, the different rear support faces 108 ad are located in the same rear plane P2 perpendicular to the spinning axis A. The rear support faces 108 ad together define the transom fixed solid 100, a rear application surface 113.

In addition, to facilitate the attachment of the various auxiliary members on the ears 105, at least the front application surface 111 is covered with a correspondingly shaped plate, with a central orifice corresponding to the cylinder body and four star branches covering each of the ears.

For this, in the presently preferred embodiment shown in the figures, the ears 105 ad of the solid fixed beam 100 extend over a length less than that of the central portion 102, so that the application surface before 111 is set back from the front end 104 of the central portion 102.

The tie rods 60 ad and the auxiliary actuating cylinders 70 ab and 80 ab bear in two opposite directions on the solid fixed beam 100 through a front attachment plate 110 and a rear mounting plate 112. The front application surface 111 solid fixed cross member 100 can receive the front mounting plate 110 which bears on said ear in the opposite direction of the extrusion direction. The rear application surface 113 makes it possible to receive the rear fixing plate 112 which bears on the said ear in the direction of extrusion.

The front attachment plate 110 has a front central opening 116 which fits on a front end 104 of the central portion 102. of the solid fixed beam 100. Advantageously, the front end 104 of the central portion 102 is provided with an external counterbore 120 having an annular bottom placed at the same level as the front application face 111 and in which comes fitting the front fixing plate 110, which is then provided with a circular central opening 116 whose inner diameter is adapted to the outside diameter of the counterbore 120.

The rear mounting plate 112 has a rear central orifice intended to allow the passage of the bottom 3 so that the rear attachment plate actually comes into plane contact on the rear application surface 113 of the solid fixed beam 100. Alternatively, and as shown on the figure 5 , the rear plate 112 is in fact made up of two sub-plates 112a and 112b disposed respectively to the right and to the left of the bottom 3.

The front attachment plate 110 (respectively the rear attachment plate 112) comprises a first series of front peripheral bores for the passage of the tie rods 118 (respectively rear peripheral bore for pulling 118 ') intended to cooperate with the conduits 106 ad so as to to support the end of a holding tie 60. Thus, the front attachment plate 110 is interposed between a front bearing surface 107 ad of an ear 105 ad and a fixing member of the tie rod 60 ad corresponding. It should be noted that the front 110 and rear 112 fixing plates are secured to the solid fixed beam 100 by the holding rods 60 a-d.

In known manner, the tie rods are prestressed and, for this, each slipped into a hollow column interposed between the bed and the fixed cross, to prevent their approximation under the effect of prestressing.

The end of such a column is represented on the figure 5 and carries the reference numeral 65 ad. Before the operation of the press, a prestressing tension is applied to the holding tie rods 60 ad, which then bear against the rear support face 108 ad of the corresponding ear 105 ad, possibly through the back plate of 112. Said hollow column, working in compression, is supported, in the opposite direction of the extrusion direction, on the front support surface 107 ad of the corresponding ear 105 ad via the front fixing plate 110.

The fixing plates 110 and 112 also support the auxiliary actuating cylinders.

For this purpose, the front fixing plate 110 and the rear fixing plate 112 each comprise a second series of peripheral bores, respectively before 119 and rear 119 'aligned in pairs and in which are threaded the auxiliary actuating cylinders: for example, as shown on the figure 5 , on each side of the spinning axis, an auxiliary actuating jack of the movable cross member 70 is supported in lower peripheral bores 119 and 119 '; and an auxiliary actuating cylinder of the container 80 is supported in upper peripheral bores 119 and 119 '. Thus, in the preferred embodiment, the peripheral bores 119 and 119 ', four in number, are arranged symmetrically on either side of a horizontal axial plane.

The body 72, 82 of each auxiliary actuating cylinder 70, 80 has a front end fixed to the front fixing plate 110, so as to bear thereon in the extrusion direction and in the opposite direction. The rear end of the body 72, 82 of each auxiliary actuating cylinder 70, 80 is supported by the rear rear fixing plate 112. In the embodiment envisaged, the reaction forces of the jacks or tie rods are applied preferably on the front mounting plate 110. Accordingly, the front mounting plate 110 is thicker than the rear mounting plate 112. The latter has the function of supporting the bodies of the auxiliary cylinders to ensure their perfect alignment.

The outer shape of a 105 ad ear can vary. Preferably, as shown on the figure 3B , the ears have a polyhedral shape composed of flat surfaces. In particular, the lower lugs may be formed to have a horizontal bottom surface 109c and 109d which together define a horizontal base plan for resting the solid fixed beam 100 on a concrete slab.

Advantageously, the lower lugs 105c and 105d respectively have grooves opening laterally outwards. The lower faces of these grooves are provided with bores opening on said lower surfaces 109c and 109d. They allow to insert fixing means perpendicularly to the horizontal lower surfaces 109c and 109d to fix the solid fixed cross member 100 to the slab.

Of course, the invention is not limited to the particular embodiment which has just been described as a simple example and also covers all the technical equivalents of the means described and their combinations.

For example, it is advantageous to make the bottom of the cylinder chamber as a separate piece welded around the rear hole of the central bore 101 but the bottom could also be integral with the cross member simply a blind bore in the central part thereof.

Moreover, the shape and number of ears 105 may vary.

Given the forces to be borne, it is advantageous to pass the tie rods in the ears, the auxiliary cylinders being mounted simply on the fixing plates 110, 112 or even on a single plate before 110, but other provisions are possible, in particular to adapt to the specific characteristics of the press and its auxiliary organs.

Claims (14)

1. Extrusion press comprising:

   • a die centered on an extrusion axis (A) and leaning on a die base,

   • a fixed crosshead (100) axially spaced out from the die base,

   • at least two tie rods (60) fastened at their ends, respectively on the die base and on the fixed crosshead (100) for the upholding of a constant distance between the last-mentioned,

   • a principal extrusion jack comprising a tubular body mounted on the fixed crosshead and closed by a bottom (3) opposite the die, said tubular body marking the limits of a cylindrical chamber (4), centered on the extrusion axis (A) and wherein slides an extrusion ram,

   • a container located between the die base and the fixed crosshead (100) and marking the limits of a housing centered on the extrusion axis for a billet of metal to be extruded through the die, due to the principal jack,

   characterized by the fact that the fixed crosshead (100) is made up of one sole monobloc solid piece manufactured by forging and comprising

   • a central part (102) being the body of the principal jack, wherein is built a central reaming (101) manufactured by internal machining of a central port obtained during the forging and making the housing of said jack, and

   • at least two ear-shaped extensions (105 a-d) stretching outwards from the central part (102) and each passed through by a shaft (106 a-d) to give way to a fastening end of the corresponding upholding tie rod (60 a-d), stretching between two spaced out faces, respectively front (107 a-d) and back (108 a-d) of said ear (105 a-d) on which are leaning, in two opposite directions, said fastening end of the tie rod (60 a-d).
2. Extrusion press according to claim 1, characterized by the fact that at least the supporting faces (107 a-d; 108 a-d) placed on the same side, respectively front or back, of the ears (105 a-d), are placed in the same plane perpendicular to the extrusion axis (A), in order together to form a supporting face (111; 113) of a fastening plate (110; 112) for the ends of the upholding tie rods (60) and comprising, on the one hand by each ear, a leaning part of the corresponding tie rod and on the other hand, between two ears, at least one leaning part for at least one operation auxiliary machine part.
3. Extrusion press according to claim 2, characterized by the fact that the ears (105 a-d) of the solid fixed crosshead (100) stretch over a length smaller than the one of the central part (102), in order to provide a front supporting face (111) set back from the front end (104) of the central part (102) and on which is going to lean the front fastening plate (110), the front fastening plate (110) being provided with a front central hole (116) into which is fitting the front end of the central part (102) of the solid crosshead.
4. Extrusion press according to claim 3, characterized by the fact that the front end (104) of the central part (102) of the solid fixed crosshead (100) is provided with an external spot facing (120) having an annular bottom placed at the same level as the front supporting face (111) and into which is going to fit the front fastening plate (110).
5. Extrusion press according to anyone of claims 2 to 4, characterized by the fact that the front fastening plate (110) is inserted between the front supporting face (107 a-d) of each ear (105 a-d) and a fastening part of the corresponding upholding tie rod (60) leaning on said ear, at least the other way around the extrusion direction.
6. Extrusion press according to claim 5, characterized by the fact that each upholding tie rod (60) is threaded inside a hollow column (65) stretching between the die base and the solid fixed crosshead (100) and is subjected to a pre-stressing tension by leaning on a back supporting face (108 a-d) of the corresponding ear (105 a-d), said hollow column leaning, the other way around, on a front supporting face (107 a-d) of said ear (105 a-d).
7. Extrusion press according to claim 6, characterized by the fact that said hollow column is leaning, through a fastening plate (110) of at least one operation auxiliary machine part (70; 80), on said front supporting face (107 a-d) of said ear (105 a-d).
8. Extrusion press according to anyone of claims 2 to 7, comprising

   • a moving crosshead (50) mounted sliding axially between the solid fixed crosshead (100) and the die base, and

   • at least two auxiliary jacks (70) of operation of the moving crosshead, each having a body (72) and a stem (74) leaning, respectively, on the solid fixed crosshead (100) and on the moving crosshead (50) for the independant moving of the latter,

   characterized by the fact that the body of each auxiliary jack of operation of the moving crosshead is fastened on a part of the front fastening plate (110) located between two ears (105 a-d) of the solid fixed crosshead.
9. Extrusion press according to anyone of claims 2 to 8, comprising at least two auxiliary jacks of operation of the container (80) each having a body (82) and a stem (84) leaning, respectively, on the solid fixed crosshead (100) and on the container, characterized by the fact that the body of each auxiliary jack of operation of the container is fastened on a part of the front fastening plate (110) located between two ears (105 a-d) of the solid fixed crosshead.
10. Extrusion press according to anyone of claims 8 to 9, characterized by the fact that the body of each operation auxiliary jack (70; 80) comprises

    • a front end fastened on the front fastening plate (110) in order to lean on it in the extrusion direction and in the other way around, and

    • a back end leaning on a back fastening plate (112) fastened on the back supporting faces (108 a-d) of the ears (105 a-d) of the solid fixed crosshead (100).
11. Extrusion press according to anyone of claims 8 to 10, characterized by the fact that the body of each operation auxiliary jack (70; 80) is threaded in at least one circular reaming of same diameter made at least on the front fastening plate (110) and comprises a shoulder leaning on said front fastening plate, at least in the direction opposite the extrusion direction.
12. Extrusion press according to anyone of previous claims, characterized by the fact that the body of the principal jack comprises

    • a cylindrical tubular part made of the central part (102) of the solid fixed crosshead (100) surrounding the principal axial reaming (101) making the housing (4) of the jack and

    • a basin-shaped bottom (3) welded along the rim of the reaming, onto a back end (103) of the tubular part.
13. Extrusion press according to anyone of previous claims, characterized by the fact that the upholding tie rods (60) and the ears (105 a-d) are centered in planes passing through the extrusion axis (A) and regularly distributed around it.
14. Extrusion press according to anyone of previous claims, characterized by the fact that the solid fixed crosshead (100) comprises two lower ears (107c, 107d) shaped so as to present lower faces (109c, 109d) defining a plane of horizontal basis for the solid fixed crosshead (100).

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