The present invention relates to a system operable to extrude metallic materials in the form of a billet in order to obtain an elongated object in a time effective way.

The patent document US-3, 123,215 relates to an extrusion press, and particularly to a tube - extrusion press. The press comprises a bolster and a die- holder. Against the latter Is impelled a container, with a container -holder. The container-holder runs with daws upon a guideway, and is rigidly connected by means of rods with a ring-traverse, which in its turn runs on guideways, and is connected, by way of rods not shown, with pistons, which slide in lateral cylinders. The main extrusion cylinder is carried by a cylinder cross-bar, and actuates an elongated platen, which is likewise slidable on the guideways. The platen is withdrawable with the aid of retracting pistons which seen in cylinders. If has window apertures on both sides, through which the mandrel implements are accessible. The mandrel is longitudinally slidable in the press ram, which is fixedly mounted on the platen. The mandrel is connected with the maπdrel-hoider by way of a bayonet joint. This mandrel-holder Is in its turn connected with the mandrel- holder-carrier by way of another connecting means. The mandrel-holder-carrier is supported in a mandrel cross-bar which runs upon guide rails, which are arranged in the platen. The connecting means thai connects the rnandrel-holder with the mandrel-holder-carrier is so arranged in relation to the window aperture that it is accessible through this aperture. The connection means is accessible from the end face of the ram when the mandrel is moved outwards. The connecting means and are here so constructed that they can be released by rotary movements, while the tools are secured against rotation. The mandrel van be slid forward out of the ram, or, after the mandrel-holder has been dismantled, can be taken out through the window aperture. The mandrel-holder is taken out of the aperture after the release of the connecting means.

A drawback with this solution is that the mandrel and mandrel-holder are taken out of the extrusion press through an aperture in the middle of the extrusion

press, which is a rather complicated solution and time consuming process. This means that it is not a time effective solution when the aim is to enable change mandrel between every shoot. This document does not mention anything how the mandrel is processed after taken out of the extrusion press. A further drawback with this solution is that due to the construction, the extrusion press is rather long in the longitudinal direction, and consequently space consuming.

The patent document GB-1 ,104,505 relates to an extrusion press for metal tubes In which a driving cylinder of the mandrel is mounted directly within and coaxially with the main ram or press plunger. In the extrusion press there Is guided in the main driving cylinder the main ram or plunger, to the forward end of which a moving cross-head guided on a bed is secured. The press plunger held in position in the moving cross-head is denoted by the reference numeral. Formed in the rear part of the press ram proper is the mandrel-driving cylinder, in the cylinder space of which the driving piston of the mandrel is mounted so as to be movable in the longitudinaf direction, and to be rotatable. A multi-sectional connecting rod is provided between the piston and the mandrel. Issuing rearwardly from the mandrel driving cylinder is a mandrel bar, the rear end of which is provided with an external thread, a securing nut, and an end stop. Flanged to the cylinder 1 is a spacing support for the stop nut. The pressure-medium supply lines to the piercing drive are also disclosed. This document does not mention how the mandrel is to be exchanged. According to fig. 1-7, disclosing two different embodiments of the extrusion press, it is not possible to withdraw the whole mandrel device, including the driving piston, backwards in order to exchange the mandrel from backwards, due to the fact that the driving piston has a larger diameter than the diameter of the hole in the main driving cylinder.

This document does not mention anything about how to exchange the mandrel, it is probably a rather complicated and time consuming process.

The patent document US-2,672,234 relates to an extrusion press or the like used in the extrusion of tubes and the forming of hollow shapes. The extrusion press (see e.g. fig 1 and 2) comprises an upper main cylinder and a lower main cylinder mounted on a pair of uprights, said uprights being supported on the main bed of the press. Each of the cylinders can have laterally extending lugs for carrying the main tie rods, said tie rods passing through lateral lugs of upright

supports. The tie rods can have nuts at either end between the uprights so as to connect the latter with the main cylinders to a conventional platen carrying an extrusion die arrangement shown generally at. The main cylinders have rams connected to the movable main cross head carrying a tool holder and extrusion stem. The extrusion stem cooperates with the biliet container bore in a conventional manner, A pair of pull back rods are connected to the movable main cross head for the purpose of retracting said movable cross head, said pull back rods being operable by the pull track cylinder assembly arranged in the stationary cylinder cross head. There preferably are two pull back rods, one being located on either side of the centre line of the machine. Extensions of the main tie rods connect stationary cylinder cross head to the main parts of the press. Pull back rods are provided with adjustable nuts which cooperate with the movable piercer cylinder cross head for the purpose of moving the piercing apparatus during certain movements of the other parts of the press. The mandrβi means in this document includes mandrel and mandrel holder. The mandrel and holder are adapted to be reciprocated in a bore in extrusion stem. The mandrel may be screw-threaded Iy engaged in mandrel holder. Mandrel holder has an enlarged end which fits snugly into a cooperating bore of the piercer stem so that the rear face of the mandrel holder is engaged by shoulder of piercer stem. The piercer stem is arranged to be moved in the piercing operation by a pair of piercer cylinders carried by the stationary cylinder cross head. The piercer cylinder rams are connected to the movable piercer cross head, which in the turn Is connected to piercer stem through a clutch. Clutch can have two small cylinders for the purpose of engaging and disengaging clutch elements with respect to piercer stem, When the clutch is engaged and the piercer cylinders energized, the mandrel will be forcibly moved forward because the action of the piercer cylinders will be transmitted to the mandrel means through rams, movable piercer cross head, clutch and the enlarged head of mandrel holder. When the mandrel has to be withdrawn immediately after extrusion and upon release of pressure in the piercer cylinders, a retracting device may be provided for moving the mandrel from an extended position relative to the extrusion stem to the position shown in Fig. 1. Such a retracting device may comprise a pair of hydraulic cylinders actuating a sliding member, said sliding member being guided in the movable cross head and being suitably supplied with fluid so as to urge the siidable member rearwardly.

The force exerted by retracting cylinders is transmitted to the mandrel holder through sliding member and shoulder of the enlarged position of the mandrel hoider. It thus is apparent that following the piercing operation and release of pressure in the piercing cylinders, the mandrel will be withdrawn into the position shown in Fig. 1 relative to the extrusion stem. In order to complete withdrawal of the mandrel means, the piercer stem is moved to the position shown in Fig. 2 by means of the double acting shifting cylinders which are rigidly mounted in the movable piercer cross head, Shifting cyiinder rams are connected to shifting cylinder cross head, said cross head being attached to an extension of the piercer stem. Upon release of the clutch, actuation of the shifting cylinders will move the piercer stem, mandrel holder and mandrel to the position shown in Fig. 2. When the piercer stem is moved rearwardly, a mandrel support (Figs, 6, 7) is positioned to receive and support the mandrel holder as it is ejected from the piercer stem, The mandrei support may comprise a pair of pivoted arms having saddles at their

piercer stem from the position shown In Fig. 7 to that shown in Fig. 10, the roller will engage surface and rotate the operating member so as to draw the connecting rod to the right, thus moving the mandrel support arms to the position shown in Figs 8 and 10 to receive the mandrel holder as it is ejected from the piercer stem. The transfer arm (Fig. 6) has a hydraulic cylinder arrangement thereon operating the tray-like member. Upon energization of hydraulic cylinder, the tray member will be advanced from the position shown in Fig. 6 to that shown in Fig. 8 engaging the mandrel means. Operation of cyiinder for the purpose of pivoting the transfer arm around 77 from the full lines shown in Fig. θ to the dashed line position 81 , wili thereby carry the mandrel hoider to a point where it can be released Into one of the sets of slots or recesses of the rotatable discs (Figs 8 and 9). The discs may be supported on a shaft which can be intermittently rotated or indexed in any conventional manner. The discs then are indexed to bring a cool mandrel means into position to be engaged by tray operation of the hydrauiic cylinder. In the cooling apparatus for the mandrels, there may be any number of stations provided. A suitable cooling means at (Fig 9) for spraying oil or other cooling medium upon the mandrels can be used.

A drawback with this solution is that the exchange of mandrels is a very complicated and consequently time consuming process.

A further drawback with this solution is that, due to the construction, the extrusion press is rather long in the longitudinally direction, and consequently

The above mentioned problems are solved with a system operable to extrude metallic materials in the form of a billet in order to obtain an elongated object according to Claim 1. The system comprises an extrusion press comprising a fixed platen having a through aperture, The system also comprises a movable platers having a through aperture and having attached thereto a stem means having a through aperture with a centre axis coinciding with the centre axis of the through aperture in the second member. The system also comprises a container means intended to hoid the billet during extrusion, and a die means, The die means and the container means are arranged in front of the through aperture of the fixed platen. The system comprises means operable to introduce a mandrei to the stem means through a backside of the movable platen via the through aperture in the movabie piaten before extrusion. After extrusion said means is operable to withdraw the mandrel the opposite way. The system also comprises a plurality of hydraulic cylinders arranged in both the fixed platen and the movable platen. The hydraulic cylinders are operable to move said movable platen in a direction to said fixed platen during said extrusion, and in a direction from said fixed platen after the

A main advantage with the system according to the present invention is that the extrusion process becomes very time effective, due to the fact that it is very easy to introduce and withdraw the mandrel.

A further advantage in this context is achieved if said hydraulic cyiinders also are operabie to function as columns,

Furthermore, it is an advantage in this context if said system also comprises a moving means arranged adjacent to said backside of said movable, platen, and operable to move said mandrel to a first position for introducing said mandrel to said stem means or withdrawing said mandrel from said stem means, and to at least a second, inoperable position remote from said first position.

A further advantage in this context is achieved if said second position is intended for inspection of a used mandrel.

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Furthermore, si is an advantage In this context if said moving means also is operable to move said mandrel to a third position comprising a temperature control means operable to coo! or heat said mandrel.

A further advantage in this context is achieved if said moving means is a revolving means having a plurality of positions for holding mandrels, which positions are evenly distributed round said revolving means.

According to another embodiment, it is an advantage if said moving means is arranged in a piane, and has a plurality of positions for holding mandrels.

Furthermore, it is an advantage in this context if said system also comprises a robot means operable to move said mandrel from said second position to a third position comprising a temperature control means operable to cool or heat said mandrel,

A further advantage in this context is achieved if said system also comprises a mandrel bar connectable to said mandrel, and is engaged by a gripping means in order to introduce said mandrel to said stem means.

Furthermore, it is an advantage in this context if said system comprises a plurality of mandrel bars,

A further advantage in this context is achieved if said system (20) comprises a plurality of container means, and a transferring means operable to move one of said container means to a position in front of said through aperture of said fixed platen (1 ) before a first extrusion shoot, and to exchange container means before the next extrusion shoot.

The above mentioned problems are also solved with a method for extruding metallic materials in the form of a billet in order to obtain an elongated object according to Claim 12, The method is performed with the aid of a system comprising an extrusion press comprising a fixed piaten having a through aperture, and a movable platen having a through aperture and having attached thereto a stem means having a through aperture with a centre axis coinciding with the centre axis of the through aperture in the movable platen. The system also comprises a container means and die means. The die means and the container

method comprises the steps; to introduce a mandrel to said stem means through a backside of said movable platen via said through aperture in said movable platen;

with the aid of a plurality of hydraulic cylinders arranged in both said fixed platen and said movable platen, to move said movable platen in a direction to said fixed platen during said extrusion, and in a direction from said fixed platen after the extrusion shoot A main advantage with the method according to the present invention is that the extrusion process becomes very time effective, due to the fact that it is very easy to introduce and withdraw the mandrel.

A further advantage in this context is achieved if said method also comprises

- with the aid of a moving means arranged in connection to said backside of said movable platen, to move said mandrel to a first position for introducing said mandrel to said stem means or withdrawing said mandrel from said stem means; and/or to move said mandrel to at least a second, inoperative position remote from said first position.

Embodiments of the invention will now be described with a reference to accompanying drawings, in

j. 1 shows a schematic side view of the extrusion press used in system according to the present invention;

Fig. 2 shows a perspective view of an embodiment of the system according to the present invention;

Fig. 3a~3d discloses schematically the extrusion process; and Fig. 4 is a flow chart of a method for extruding metallic materials in the form of a billet in order to obtain an elongated object according to the present

In fig. 1 there is disclosed a schematic side view of an extrusion press 22 used in the system 20 according to the present invention. (See fig. 2). The extrusion press 22 comprises a fixed, platen 1 , and a movable, platen 2 having a through aperture 7. As is disclosed in fig. 1 a stern means 4 is attached to the movable, platen 2. The stem means 4 has a through aperture 5 with a centre axis

8 coinciding with the centre axis if the through aperture 7 in the movable, platen 2. By this feature it is more easy to introduce the mandrel to its intended place in the stem means 4 without being mounted from the front side 8 of the stern means 4. Instead the mandrel is introduced to its intended place from the backside 9 of the movable, platen 2. The extrusion press 22 also comprises a container means 10 intended to hold the billet 30 (see fig. 3a~3d) during extrusion. The extrusion press 22 also comprises a die means 11. As ϊs apparent in fig.1 the die means 11 and the container means 10 are arranged in front of the through aperture 12 of fixed platen 1. The extrusion press 22 also comprises, in this particular embodiment, four hydraulic cylinders 3 (see also fig, 2) arranged in both the fixed platen 1 and the movable platen 2, The hydraulic cylinders 3 are operable to move the movable piaten 2 in a direction to the fixed platen 1 during said extrusion, and in a direction from the fixed platen 1 after the extrusion shoot. The hydraulic cylinders 3 are arranged in a symmetrical way in both the fixed platen 1 and the movable platen 2 in order to distribute the press force equally between each other. It is to be pointed out that the hydraulic cylinders 3, in the embodiment disclosed in fig. 1 , also are operable to function as columns. This construction of the extrusion press 22 makes it very compact and not so space consuming.

It is to be pointed out that fig, 1 only discloses the extrusion press 22 schematically, and not in full scale, or according to scale.

In fig 2 there is disclosed a perspective view of an embodiment of the system 20 according to the present invention, As is apparent in fig. 2, the system 20 comprises the extrusion press 22 disclosed in more detail in fig. 1. The same reference signs have been used in both figs. 1 and 2 to designate the same elements. The system 20 comprises a plurality of container means 10. The system 20 also compπses a transferring means 17 operable to move one of the container means 10 to a position in front of the through aperture 12 of the fixed platen 1 before a first extrusion shoot. Furthermore, before the next extrusion shoot, the transferring means 17 is operable to exchange container means 10. The used container means 10 is moved to a place for cleaning and/or loading of the billet 30, and a new container means 10 is put in place for the next extrusion shoot. This means that the extrusion process gets even faster. According to one embodiment the transferring means 17 is in the form of a rail arranged horizontally in connection to and in front of the fixed platen 1 , as is disclosed in fig. 2, and several

railbound wagons, each of which is carrying a container means 10, As also is apparent in fig. 2 the system 20 also comprises a moving means 13 arranged adjacent to the backside 9 of the movable, platen 2, The moving means 13 is operable to move the mandrel 16 (see fig. 3a-3d) to a first position 14 intended for

5 introducing of the mandrel 16 to the stem means 4 (see fig, 1 ) or withdrawal of the mandrel 18 from the stem means 4, The moving means 13 is also operabie to move the mandrel 18 to a second position 15, which e.g. can be intended for inspection of a used mandrel 18. in the embodiment disclosed in fig. 2 the moving means 13 is in the form of a revolving means 13 _» wherein the mandrels 18 are io fixated in the different positions 14, 15. In the generai case, the revolving means 13 has a plurality of positions for holding mandrels 18, which positions are evenly distributed round the revolving means 13. The moving means 13 is also operabie to move the mandrel 16 to a third position 18 comprising a temperature control means 19 operable to cool or heat the mandrel 18 in order to achieve a for the s 5 extrusion shoot desired temperature of the mandrel 16. In the embodiment disclosed in fig. 2 the system 20 also comprises a robot means 24 which is operable to move the mandrel 18 from the second position 15 to the third position 18. The system 20 can also have a mandrel bar 26 which is connectable to the

?.o introduce the mandrel 18 to the stem means 4. According to one embodiment the system 20 comprises a plurality of mandrel bars 26, e.g. one mandrel bar 26 for each position of the moving means 13/revolviπg means 13

In figs. 3a~3d there is schematically disclosed the extrusion process, wherein fig. 3a discloses the press in a position for ioading of the billet 30, fig 3b

25 discloses the billet 30 ready for extrusion, fig. 3c discloses the extrusion, and fig. 3d discloses when the extrusion is finished.

In fig. 4 there is disclosed a flow chart of a method for extruding metallic materials in the form of a billet in order to obtain an elongated object according to the present invention. The method is performed with the aid of the system 20,

30 disclosed in fig. 2, according to the present invention. The method begins at step 50. The method continues, at block 52, with the step: to introduce a mandrel 18 to the stem means 4 through a backside 9 of the movable platen 2 via the through aperture 7 in the movable platen 2. Thereafter, at block 54, the method continues with the step: with the aid of a plurality of hydraulic cylinders 3 arranged in both the

fixed platen 1 and the movable platen 2, to move the movable platen 2 in a direction to the fixed platen 1 during said extrusion, and in a direction from the fixed platen 1 after the extrusion shoot. The method is completed at block 56.

According to another embodiment, the method also comprises the steps: with the aid of a moving means 13 arranged in connection to the backside 9 of the movable platen 2, to move the mandrel 18 to a first position 14 for introducing the mandrel 18 to the stem means 4, or withdrawing the mandrel 16 from the stem means 4; and/or to move the mandrel 18 to at least a second, inoperative position 15 remote from the first position 14. The invention is not limited to the described embodiments, it wili be evident for those skilled in the art that many different modifications are feasibie within the scope of the following Claims.

The revolving means 13 can e.g. be exchanged to a moving means 13 arranged in a plane, and having a plurality of positions for holding mandrels 18. The rail which can be a part of the transferring means 17 can e.g. be arranged vertically in connection to and in front of the fixed platen 1 ,