The object of the present invention is an extrusion press with a device to automatically remove metal material deposited on a mandrel or spindle of such press during extrusion according to the preamble of the main claim.

As is known, an extrusion press is provided with a mandrel adapted to penetrate within a container where a metal billet is placed and provided with its own extrusion die in order to extrude an article of desired shape from such billet. A sealing ring or "heel" is provided at such a die.

The mandrel moves along its own axis under the thrust action of a pressing member in order to penetrate into the container and extrude the article. After this operation, the mandrel retracts from said container away from it in order to allow the introduction of another billet into the container. Then, the extrusion process resumes.

The mandrel is also supported by a rotating body that sets it in rotation about such longitudinal axis at least to lubricate it.

During the extrusion, residues of metal material, such as aluminum, are deposited on the mandrel surface, and it remains on such surface when such mandrel is removed from the container after the extrusion. Such materials, accumulating over time, during the translational motion of the mandrel can contact the sealing element (heel) and/or the die, thus damaging them. In particular, the material accumulated on the surface could penetrate into a compartment behind the mandrel where there are members for the axial movement and rotation of the same. This material "dirties" and produces clear damage. Moreover, for example, with subsequent contacts, the heel loses its sealing function and the extrusion operation may result in the leakage of metal material, which is at a very high temperature, from an inadequate end of the container (the mandrel inlet end).

It is therefore necessary to remove such "accumulation" material from the surface of the mandrel.

Currently, the mandrel is separated from the support member thereof and is treated with descaling agents like soda. However, this operation requires the shutdown of the machine (extrusion press), the intervention of operators thereon, the removal of the mandrel and its cleaning, which usually takes place by immersing it in a bath of such descaling agent, like soda. All of this involves considerable time and thus has considerable costs.

DE 31 20 770 describes an extrusion press provided with a device for cleaning the mandrel from the material that has accumulated on the surface thereof during the extrusion. The known device comprises a rotatable mechanism to rotate the mandrel about its axis, a "smoothing or grinding" mechanism (grinder mechanism) adapted to grind the free end portion of the mandrel and a transfer mechanism for moving such grinding mechanism towards and away from the mandrel.

DE 31 20 770 forms the basis for the precharacterizing part of claim 1 of the present document.

The object of the present invention is to provide an extrusion press provided with a device that is automatically and accurately able to remove the metal material that accumulates on the surface of the mandrel of an extrusion press without the need to remove it from the machine.

Another object is to provide a press with a device of the above type which can be used without any time constraint between two or more extrusions.

A further object is to provide a press with a device of the above type which can allow maintaining an optimal functionality of the machine for long periods without subjecting it to unnecessary shutdown periods.

Another object is to provide a press with a device of the above type which allows the lubrication of the mandrel during the removal of the metal material from its surface.

These and other objects that will become apparent to the person skilled in the art are achieved by an extrusion press provided with a device for automatically removing metal material from the surface of a mandrel of such press according to the accompanying claims.

For a better understanding of the present invention, the following drawings are attached by way of non-limiting example, in which:

• figure 1 shows a longitudinal sectional view of an extrusion press provided with a device for removing metal material from the surface of a mandrel of such press according to the invention;
• figure 2 shows a perspective view from one side of the device mounted on the press according to the invention;
• figure 3 shows a view according to section 3-3 in figure 2;
• figure 4 shows a perspective view from another side of the device mounted on the press according to the invention;
• figure 5 shows a front view of the device mounted on the press according to the invention; and
• figure 6 shows a side view of the device mounted on the press according to the invention where the solid line shows a first working position thereof and the dotted line shows a second working position thereof.

With reference to the above figures, an extrusion press 1 is shown in its entirety in figure 1 and comprises a base 2 that is associated with several known parts adapted to allow the extrusion of an aluminum (or other metal) billet, in particular comprising a container 3 where an extrusion die 4 is placed and supported by the base, a main axially movable cylinder 5 in which a rotatable support member 6A of a mandrel 7 moves, provided with a free end or mandrel head 8 and attached at the other end 8A to the support member 6A. The latter is placed inside a fixed body 6.

A drilling piston 10 moves mandrel 7 through the action on the support member 6A, said movement being obtained along a longitudinal axis W of the mandrel coincident with the longitudinal axis of piston 10, of container 3, of die 4 and ultimately, of the extrusion press 1. Such support member 6A is set in rotation about axis W by a usual hydraulic motor 6B carried by body 6, a motor that in this way also sets mandrel 7 in rotation about such axis.

A device 15 is provided in the vicinity of die 4 and container 3, adapted to automatically remove the metal material that accumulates, with subsequent extrusions, on the surface of mandrel 7. Such removal occurs after (or before) any extrusion, i.e. when the spindle is still outside die 4 with head 8 thereof. Device 15 is attached to container 3 through a casing 18 and is placed on a side 3A of such container facing towards mandrel 7.

Said device 15 is radially movable towards axis W of mandrel 7. In the embodiment shown in the figures, such device comprises brushing means 20 placed on a side of mandrel 7 and adapted to contact the surface thereof when, as said, it is outside the extrusion die and is preferably in rotation. Such brushing means 20 selectively (i.e. only when desired) contact the outer surface of mandrel 7 and remove therefrom the metal material that has deposited thereon. Generally, the intervention on said surface takes place after a relatively large number of operations.

The intervention takes place by moving such means with respect to mandrel 7 and towards it.

More in particular, device 15 comprises a body or frame 22 (preferably box-shaped in order to limit the weight thereof) at a face 23 whereof the brushing means 20 are provided, movable away from it. The latter comprise a metal brush 25 integral to a shaft 26 set in rotation by an electric motor 27. The motor has an output shaft 28 on which a pulley 29 is keyed, adapted to move a belt 30; the latter transfers the motion of shaft 28 to a toothed gearing 31 keyed on shaft 26 and thereby to the metal brush 25.

In the figures, motor 27 and brush 25 are associated with a box-shaped support 32 carried by frame 18 and at a distance between them. Members 38 for moving the brush (or the support 32 thereof) along side 23 of said frame are provided at a face 34 of said frame 22, opposite to 23. Of course, nothing prevents a man skilled in the art from arranging the motor in the vicinity of brush 25 (on the same side or on opposite sides of the box-shaped support 32) and connect them in a different manner (such as through toothed wheels or pinions in direct coupling).

In the embodiment described, belt 30 is inserted within the box-shaped support 32, as are the toothed gearing or pulley 29. This protects them further from any leakage of metal from the extrusion press and from bumps, and also allows lubricating them during operation with a micro-lubrication system per se known (and not shown). Moreover, support 32 is made since movable parts are contained and these must be closed and safe as much as possible. The output shaft 28 and 26 are supported by the box-shaped support 32 through suitable bearings 40.

The metal brush 25 is preferably inserted in a casing 41, open in 42 on a side 43, from which the brush partially protrudes to contact mandrel 7 and remove the metal accumulated on its surface.

Advantageously, at opening 42 of side 43 and on at least one of its sides 42A (in the example of the figures, on both opposite sides), a corresponding nozzle 47 is provided for dispensing a lubricating product. Such lubricant is not dispersed around the mandrel but it dispensed only on the part on which the metal brush 25 works.

As said, the box-shaped support 32 is movable along face 23 of frame 18. In particular, such support 32 is associated with sliding blocks or carriages 50 sliding in guides 51 of frame 22 when the moving means 38 are actuated (by a device control unit, not shown, which is connected or is part of a control unit of the extrusion and its single parts).

Such moving means comprise a gearmotor or electric motor 55 attached to body 18 and actuating a worm screw 56 (for example, ball recirculating) cooperating with a threaded bush 57 integral with a shelf 58 projecting from support 32. The rotation of the screw generated by the gearmotor or electric motor 55 results in the displacement of bush 57 along the screw itself and thus to the corresponding movement of shelf 58 and support 32 along guides 51. In this way, brush 25 can reach (or move away from) mandrel 7 to remove, as said, the material that has deposited thereon.

Said movement is also controlled by usual displacement sensors: for example, the vertical movement is controlled by an encoder built into the motor. The whole is controlled and managed by PLC.

The brushing means 20 can autonomously move parallel to frame 22 through the movement of support 32 generated by motor 55 so as to reach mandrel 7; during this movement, brush 25 is set in rotation by motor 27. The brush drops to touch the mandrel and is rotated at "high speed". The mandrel is set in rotation and simultaneously it is axially translated so as to have a "helical" cleaning. The mandrel rotation about axis W or at least that of brush 25 results in a brushing action on the surface of such mandrel 7 which causes the removal of the metal material (or residue) deposited (or hardened) thereon after one or (preferably) multiple extrusions.

The movement of such means 20 is controlled by the above control unit.

A preferred embodiment of the invention has been described. However, still others are possible within the context of the invention described above. For example, it may be contemplated that only one between the brushing means 20 and mandrel 7 rotates to remove the material present from the surface of the latter. These solutions also fall within the scope of the following claims.