Patent Description:
It is known to use front loading extrusion presses in the technology of producing metal items, in particular metal section bars, by extruding a billet.

A conventional front loading extrusion press of the known type is depicted in <FIG> and comprises a main cylinder <NUM>, two side or return cylinders <NUM>, two or more cylinders <NUM> for translating (in two opposite translation directions) a container <NUM>, an extrusion crosspiece with extrusion die <NUM>, and a movable crosspiece <NUM>.

The main cylinder <NUM>, usually of the hydraulic type, is the largest among those with which the press is equipped and ensures the greatest push force by means of the respective extrusion punch <NUM>; the increased dimensions of the chamber of the main cylinder <NUM> make the extrusion punch <NUM> unsuitable for quick and/or fast movements. The main cylinder <NUM> conventionally is of the single-action type, wherein the chamber of cylinder <NUM> is placed in communication with a pre-filling valve <NUM> which in turn is in communication with a tank (not depicted) of a hydraulic fluid, conventionally hydraulic oil. Closing of valve <NUM> and the subsequent introduction of pressurized oil by means of high pressure pumps (not depicted) into the chamber of cylinder <NUM> results in generating the advancing translation of the extrusion punch <NUM> towards die <NUM>. Contrarily, quick movements of the extrusion punch <NUM>, both forwards towards the die <NUM> and backwards (in jargon, for the "return" of the extrusion punch <NUM>), are obtained by means of the two side cylinders <NUM>. In particular, prior to the actual extrusion step, the billet is blocked between the extrusion punch <NUM> and die <NUM> by means of the side cylinders <NUM>, wherein contrarily, at the end of the actual extrusion step, the extrusion punch <NUM> is "returned" (moved away from die <NUM>), again by means of the side cylinders <NUM>. As for container <NUM>, it is translated (according to the methods below) both towards die <NUM> and away from die <NUM> by means of the dedicated cylinders <NUM>.

A standard extrusion cycle performed by means of a press according to the prior art of the type depicted in <FIG> may be summarized as follows.

During a first step, a billet is loaded between the front face of the extrusion punch <NUM> and die <NUM>;.

The subsequent extrusion cycle thus starts with loading a new billet between the extrusion punch <NUM> and die <NUM> and continues according to the steps summarized above.

Extrusion presses according to the prior art of the type depicted in <FIG> have various disadvantages and/or drawbacks which the Applicant wanted to overcome or at least minimize by the present invention.

Firstly, it is worth considering that the presence of the side cylinders makes the press decidedly cumbersome, wherein the dimensions of the press and the need to provide adequate maneuvering spaces for the side cylinders make it difficult, if not impossible, to place the press in work environments with small dimensions.

Moreover, the side cylinders increase the need for maintenance and/or repair interventions on the press, given that they are subject to breakdowns and/or malfunctions.

And again, as anticipated, the use of the side cylinders during the actual extrusion step as support to the action of the main cylinder may give rise to undesired bending and/or distortions, for example in the event the force generated by one of the two cylinders does not exactly correspond to that generated by the second cylinder, or in the event of slender rods subject to buckling.

Finally, the presence of the side cylinders results in an oversizing of at least some of the components of the press to be necessary, for example of the movable punch holder crosspiece and the main cylinder crosspiece, also in this case with negative repercussions in terms of excessive dimensions and overall cost of the press.

Examples of extrusion presses according to the prior art are known from each of the documents <CIT> (basis for the preamble of claim <NUM>), <CIT> and <CIT>.

Therefore, it is a primary object of the present invention to provide an extrusion press, in particular a front loading extrusion press, which allows overcoming or at least reducing the disadvantages and/or drawbacks encountered in the extrusion presses according to the prior art.

In particular, it is the object of the present invention to provide an extrusion press which does not provide the use of the side cylinders <NUM>, positioned as in <FIG>, commonly used for quickly moving the rod of the main cylinder.

Moreover, among the objects of the present invention there is the reduction of the hydraulic complexity of the machine (eliminating hydraulic blocks and pipes).

It is a further object of the present invention to provide a solution which allows the reciprocal rigid connection of the extrusion punch and the main cylinder crosspiece.

According to the invention, the use of the side cylinders may be avoided by means of a solution which allows, when necessary and/or required, reciprocally rigidly restraining the movable punch holder crosspiece and the container so that when restrained to the movable punch holder crosspiece, the translations of the container result in corresponding translations of the movable punch holder crosspiece (and therefore, of the extrusion punch because it in turn is restrained to the movable punch holder crosspiece).

Therefore, based on both the previously summarized preset objects and the above considerations, the present invention relates to an extrusion press according to main claim <NUM>, embodiments of the present invention being defined by the dependent claims.

According to a described embodiment, the extrusion press for producing metal items by extruding a metal billet comprises a main crosspiece, an extrusion die and a main cylinder including an extrusion punch adapted to be translated in two opposite directions, wherein the translation of said main cylinder in a first extrusion direction results in a push against said billet and in the extrusion of said billet through said extrusion die, said press comprising a container and a movable punch holder crosspiece, both being translatable in two opposite directions parallel to the translation directions of said extrusion punch, wherein said container is adapted to be translated by means of at least a first dedicated cylinder including a first dedicated rod rigidly fastened to said container, and wherein said container is adapted to be moved close to said extrusion die by means of said dedicated first cylinder and rod so as to contain said billet; said press comprising a first dedicated rigid bar rigidly fastened to said movable punch holder crosspiece; wherein said press comprises first locking means adapted to alternately lock or free said first dedicated rigid bar, wherein said first dedicated rigid bar extends through the main cylinder crosspiece of said main cylinder, wherein said first locking means are accommodated in said main cylinder crosspiece of said main cylinder, wherein said first dedicated rigid bar extends through said first locking means, and wherein the locking action of said first locking means on said first dedicated rigid bar results in the reciprocal rigid connection of said main cylinder crosspiece and movable punch holder crosspiece.

According to an embodiment, said press comprises second locking means adapted to alternately lock or free said first dedicated rod, wherein the locking action of second first locking means on said first dedicated rod results in the reciprocal rigid connection of said container and movable punch holder crosspiece, and therefore wherein with said first dedicated rod blocked by said second locking means, the translation of said container results in the simultaneous translation of said movable punch holder crosspiece.

According to an embodiment, said at least a first dedicated rod extends through said movable punch holder crosspiece, wherein said second locking means are accommodated in said transverse head.

According to an embodiment, said at least a first dedicated rod extends through said second locking means.

According to an embodiment, said second locking means comprise a deformable sleeve through which said first dedicated rod extends, wherein said deformable sleeve is accommodated in a chamber in communication with a circuit of a pressurized fluid, and wherein the introduction of said pressurized fluid into said chamber results in the deformation of said deformable sleeve and in a transverse pressure applied by said sleeve to said first dedicated rod, and therefore in the blocking of said dedicated rod.

According to an embodiment, said container is adapted to be translated by means of at least a second dedicated cylinder including a second dedicated rod rigidly fastened to said container, wherein said container is adapted to be moved close to said extrusion die by means of said dedicated first cylinder and rod and dedicated second cylinder and rod so as to contain said billet at least partially; wherein said press comprises third locking means adapted to alternately lock or free said second dedicated rod, wherein the locking action of said third locking means on said second dedicated rod results in the reciprocal rigid connection of said container and movable punch holder crosspiece, and therefore wherein with said second dedicated rod blocked by said third locking means, the translation of said container results in the simultaneous translation of said movable punch holder crosspiece.

According to an embodiment, said at least a second dedicated rod extends through said movable punch holder crosspiece, wherein said third locking means are accommodated in said movable punch holder crosspiece.

According to an embodiment, said second dedicated rod extends through said third locking means.

According to an embodiment, said third locking means comprise a deformable sleeve through which said second dedicated rod extends, wherein said deformable sleeve is accommodated in a chamber in communication with a circuit of a pressurized fluid, and wherein the introduction of said pressurized fluid into said chamber results in the deformation of said deformable sleeve and in a transverse pressure applied by said sleeve to said second dedicated rod, and therefore in the blocking of said dedicated rod.

According to an embodiment, said first locking means comprise a deformable sleeve through which said first dedicated rigid bar extends, wherein said deformable sleeve is accommodated in a chamber in communication with a circuit of a pressurized fluid, and wherein the introduction of said pressurized fluid into said chamber results in the deformation of said deformable sleeve and in a transverse pressure applied by said sleeve to said first dedicated rigid bar, and therefore in the blocking of said first dedicated rigid bar.

According to an embodiment, said press comprises a second dedicated rigid bar rigidly fastened to said movable punch holder crosspiece; wherein said press comprises fourth locking means adapted to alternately lock or free said second dedicated rigid bar, and wherein the locking action of said fourth locking means on said second dedicated rigid bar results in the reciprocal rigid connection of said main cylinder crosspiece and movable punch holder crosspiece.

According to an embodiment, said second dedicated rigid bar extends through the main cylinder crosspiece, wherein said fourth locking means are accommodated in said main cylinder crosspiece.

According to an embodiment, said second dedicated rigid bar extends through said fourth locking means.

According to an embodiment, said fourth locking means comprise a deformable sleeve through which said second dedicated rigid bar extends, wherein said deformable sleeve is accommodated in a chamber in communication with a circuit of a pressurized fluid, and wherein the introduction of said pressurized fluid into said chamber results in the deformation of said deformable sleeve and in a transverse pressure applied by said sleeve to said second dedicated rigid bar, and therefore in the blocking of said second dedicated rigid bar.

A description is provided below of the embodiments of the present invention depicted in the drawings, in which:.

In any case, it should be noted that the present invention is not limited to the embodiments described later and depicted in the drawings; contrarily, all those variants and/or modifications of the embodiments described below and depicted in the accompanying drawings which will be apparent and obvious to those skilled in the art are part of the present invention as long as they fall within the scope of the appended claims.

The application of the present invention is particularly advantageous in the case of front loading extrusion presses, this thus being the reason why the present invention is described below with particular reference to the applications thereof to a front loading press.

Nonetheless, it must be highlighted that the possible applications of the present invention are not limited to those described below. Contrarily, the present invention is adapted to be conveniently applied in all the cases in which independently reciprocally restraining two translatable parts or components is required, so that the translation of one results in the simultaneous translation of the other and vice versa.

The extrusion press depicted in <FIG> is identified by reference numeral <NUM> and comprises a main cylinder <NUM>, two or more cylinders <NUM> for translating (in two opposite translation directions) a container <NUM>, an extrusion die <NUM> and a movable punch holder crosspiece <NUM>.

The main cylinder <NUM> is of the single-action type, wherein the chamber of cylinder <NUM> is placed in communication with a pre-filling valve <NUM> which in turn is in communication with a tank (not shown) of a hydraulic fluid, conventionally hydraulic oil. The closing of valve <NUM> following the increase of the pressure of the fluid (oil) in the chamber of cylinder <NUM> generates the forward translation of the extrusion punch <NUM> towards die <NUM>. Contrarily, quick movements of the extrusion punch <NUM>, both forwards towards die <NUM> and backwards (in jargon, for the "return" of rod <NUM>), are obtained by means of the two dedicated cylinders <NUM>, wherein at the end of the actual extrusion step, the extrusion punch <NUM> is "returned" (moved away from die <NUM>), again by means of the dedicated cylinders <NUM>. Indeed, as mentioned, press <NUM> according to the present invention is characterized by an innovative solution which allows container <NUM> and the movable punch holder crosspiece <NUM> and/or the movable punch holder crosspiece <NUM> and the main cylinder <NUM> to be reciprocally restrained when required and/or necessary, said innovative solution being described below with reference to <FIG>.

Reference numerals <NUM> in <FIG> identify the rods of the respective cylinders <NUM> (dedicated to the movement by translation of the container <NUM> and the movable punch holder crosspiece <NUM>); the ends of the rods <NUM> are restrained to container <NUM>, wherein the rods <NUM> extend through the movable punch holder crosspiece <NUM>. In particular, each rod <NUM> extends through respective locking or clamping means <NUM> accommodated in the movable punch holder crosspiece <NUM>.

The construction details of said clamping means <NUM> (as the other clamping means <NUM> described below) are depicted in <FIG>, in which reference numeral <NUM> identifies said rod. As depicted, the locking means <NUM> comprise a hose or deformable sleeve <NUM> (made of special bronze) shaped like a hollow cylinder, wherein said hose <NUM> is accommodated in a chamber <NUM> in communication with a circuit of pressurized fluid (for example, oil) by means of a delivery <NUM> (reference numeral <NUM> indicating an air vent), wherein the introduction of oil into chamber <NUM> results in a pressure on hose <NUM>, and therefore in a transverse force applied by hose <NUM> to rod <NUM>, and therefore ultimately in a blocking or clamping of rod <NUM> such as to avoid longitudinal movements of rod <NUM> (with respect to the movable punch holder crosspiece <NUM>). It indeed is shown that given that the locking or clamping means <NUM> are accommodated in the movable punch holder crosspiece <NUM>, the blocking or clamping of the rods <NUM> (of at least one rod <NUM>) results in the reciprocal restraint between the rods <NUM> and the movable punch holder crosspiece <NUM>, and therefore between the movable punch holder crosspiece <NUM> and container <NUM>, and each translation of container <NUM> results in a corresponding translation of the movable punch holder crosspiece <NUM>.

Again as depicted, the movable punch holder crosspiece <NUM> comprises a pair of rigid bars <NUM> (<FIG>, <FIG>) which extend through respective locking means <NUM> accommodated in the main cylinder crosspiece <NUM> of the main cylinder <NUM> (<FIG>, <FIG>); given that said locking means <NUM> are similar to the locking means <NUM> described above with reference to <FIG>, a further description thereof is omitted for reasons of brevity. Moreover, it should be noted that said locking means <NUM> comprise a deformable hose <NUM> (similar to hose <NUM> of the locking means <NUM>) which is shaped like a hollow cylinder, wherein said hose <NUM> is accommodated in a chamber <NUM> in communication with a circuit of pressurized fluid (for example, oil) by means of a delivery <NUM> (reference numeral <NUM> indicating an air vent), wherein the introduction of oil into chamber <NUM> results in a pressure on hose <NUM>, and therefore in a transverse force applied by hose <NUM> to bar <NUM>, and therefore ultimately in a blocking or clamping of bar <NUM> such as to avoid longitudinal movements of bar <NUM> (with respect to the main cylinder crosspiece <NUM> which is rigidly connected to the fixed surface of the foundations). It indeed is shown that given that the locking or clamping means <NUM> are accommodated in the main cylinder crosspiece <NUM>, the blocking or clamping of the bars <NUM> (of at least one bar <NUM>) results in the reciprocal restraint between the movable punch holder crosspiece <NUM> and the main cylinder crosspiece <NUM>.

An extrusion cycle which may be carried out by means of a press according to one of the embodiments depicted in the drawings is described below by way of nonlimiting example.

It has thus been demonstrated, by means of the above detailed description of the embodiments of the present invention depicted in the drawings, that the present invention allows achieving the desired results and overcoming or at least limiting the drawbacks found in the prior art.

In particular, the present invention provides an extrusion press, for example but not only a front loading extrusion press, which does not require the use of the side cylinders contrarily commonly used in the presses according to the prior art to quickly move the main rod, and which is thus characterized by low manufacturing dimensions and costs, requires less maintenance and is less subject to breakdowns and/or malfunctions and which moreover, avoids the risk of bending and/or distortions contrarily present in the presses according to the prior art because resulting from the use of the side cylinders during the actual extrusion step.

Although the present invention was clarified above by means of the detailed description of the embodiments depicted in the drawings, the present invention is not limited to the embodiments described and depicted in the drawings, contrarily, all those variants and/or modifications of the embodiments described and depicted in the accompanying drawings which will be apparent and obvious to those skilled in the art fall are part of the present invention as long as they fall within the scope of the appended claims.

For example, the locking means described with reference to the drawings may be replaced with "KOSTIRKA" type locking units or alternatively also with mechanical locking means such as ratchets or the like.

Claim 1:
An extrusion press (<NUM>) comprising a main crosspiece (<NUM>), an extrusion die (<NUM>) and a main cylinder (<NUM>) including an extrusion punch or pressing rod (<NUM>) adapted to be translated in two opposite directions, wherein the translation of said extrusion punch (<NUM>) in a first extrusion direction results in a billet being pushed and extruded through said extrusion die (<NUM>), said press (<NUM>) comprising a container (<NUM>) and a movable punch holder crosspiece (<NUM>), both being translatable in two opposite directions parallel to the translation directions of said extrusion punch (<NUM>), wherein said container (<NUM>) is adapted to be translated by means of at least a first dedicated cylinder (<NUM>) including a first dedicated rod (<NUM>) rigidly fastened to said container (<NUM>), and wherein said container (<NUM>) is adapted to be moved close to said extrusion die (<NUM>) by means of said dedicated first cylinder (<NUM>) and rod (<NUM>) so as to contain said billet; characterized in that said press (<NUM>) comprises a first dedicated rigid bar (<NUM>) rigidly fastened to said movable punch holder crosspiece (<NUM>); in that said press (<NUM>) comprises first locking means (<NUM>) adapted to alternately lock or free said first dedicated rigid bar (<NUM>), in that said first dedicated rigid bar (<NUM>) extends through the main cylinder crosspiece (<NUM>) of said main cylinder (<NUM>), in that said first locking means (<NUM>) are accommodated in said main cylinder crosspiece (<NUM>) of said main cylinder (<NUM>), in that said first dedicated rigid bar (<NUM>) extends through said first locking means (<NUM>) and in that the locking action of said first locking means (<NUM>) on said first dedicated rigid bar (<NUM>) results in the reciprocal rigid connection of said extrusion punch (<NUM>) and the main cylinder crosspiece (<NUM>).