WO2006061863A1

WO2006061863A1 - Press unit provided of multiple dies for obtaining manufactured products

Info

Publication number: WO2006061863A1
Application number: PCT/IT2004/000690
Authority: WO
Inventors: Federico Vescovini
Original assignee: Amafa Service S.R.L.
Priority date: 2004-12-10
Filing date: 2004-12-10
Publication date: 2006-06-15

Abstract

A press unit (10) for obtaining manufactured metal products, to produce metal elements such as for example bushings, nuts or other elements with blind or through holes, screws, standard and specially shaped extruded or pressed products, consists of a hydraulic and/or mechanical and/or other type of press suitable for machining metal. Close to the said unit (10) is at least one carriage (14) sliding on a bed (13) which is equipped with at least two dies (15, 16), each of which is designed to contain respective pieces to be machined (17, 18). Said carriage comprises movement means in order to transfer the pieces to be machined from a position below the punch of the press to a position away from the punch and vice versa.

Description

"PRESS UNIT PROVIDED OF MULTIPLE DIES FOR OBTAINING MANUFACTURED PRODUCTS"

TECHNICAL FIELD This invention concerns a hydraulic, mechanical or other type of press for the cold, semi-hot or hot extrusion of metal pieces by means of multiple pressing processes and with the use of multiple die stations.

More specifically, this invention refers to a press with multiple stations that makes it possible to carry out cold, semi-hot or hot extrusion processes for the production of metal elements such as bushings, nuts or other elements with blind or through holes, screws, extruded or pressed products with standard and special shape etc., made from steel or other metal materials such as aluminium, copper, brass, etc. and with an external diameter approximately greater than 16 mm. The press according to this invention comprises multiple die carriages, able to increase the production capacity of the machine and reduce the product change times and the overall dimensions, and more specifically in such a way that the pressed products can be extracted and the pieces to be pressed can be loaded in all the stations outside the station in the pressing area, separating the pressing process from the product extraction and insertion stage as normally occurs in traditional presses with fixed dies positioned below the press.

This invention can be applied in the mechanical industry field for the production of extruded/pressed items such as for example bushings, nuts or other elements with blind or through holes, screws, extruded or pressed products with standard and special shape etc., made from steel or other metal materials such as aluminium, copper, brass, etc.

BACKGROUND ART It is known that the production of extruded/pressed elements such as for example bushings, nuts or other elements with blind or through holes substantially takes place according to four possible procedures: - cold pressing by means of horizontal mechanical presses; - cold or hot pressing using vertical mechanical presses and subsequent machining restart;

- turning of previously laminated tubes in the case of cylindrical products with through holes such as, for example, bushings; - removal of chips starting from full blanks.

- cold or hot pressing using vertical hydraulic, mechanical or other types of multipress machines with several fixed die pressing stations.

Multipress machines are those most recently used as they are able to overcome the problems of the other systems, as regards for example investment costs, the short life of the punches, punching dies or other tools subject to particular stress in the pressing process due to the rise in temperature, or to the fact that there is an alteration of the fibres as a result of the considerable work hardening with degrading of the mechanical characteristics of the finished product due mainly to violent and non-progressive deformation as in the case of hydraulic presses.

Multipress machines are designed to produce semifinished products such as bushings, nuts, screws or similar products according to consecutive machining stages, for example according to the procedure illustrated in figure 1, which represents a traditional type of machining with the steps indicated from A to F.

These machines consist of a plurality of stations equipped with hydraulic, mechanical or other types of presses connected by means of a transfer unit for the movement of the pieces being machined.

Multipress machines are designed to cold press crop ends of steel or other material using hydraulic, mechanical or other types of multistation presses to obtain pieces of various shapes and sizes with diameters or cross-sections greater than 30 millimetres.

. This unit advantageously consists of a gripper device powered by a hydraulic, mechanical or pneumatic source of energy according to the weight of the pieces.

Each of the stations that make up a traditional multipress machine comprises a press with a considerable and often excessive development in height, due to the space necessary for the extraction and insertion of the pieces from and into the die.

The die is in fact positioned right below the press and it is obvious that the longer the piece to be pressed, the longer the stroke must be. Therefore, in order to be as versatile as possible, every machine must foresee the possibility of also machining very long pieces, thus penalising the productivity of the unit that has to travel the entire stroke necessary to pass the full length of the product to be extracted rather than the length of the piece to be pressed. The productivity of traditional multipress machines is therefore limited despite being greater than that offered by manually operated single press machines.

DESCRIPTION OF THE INVENTION

This invention proposes to provide a machine designed to produce semifinished metal elements that is able to eliminate or significantly reduce the disadvantages described above.

This invention also proposes to provide a machine for obtaining metal elements that is easy to construct in order to be economically advantageous. . This is achieved by means of a multipress machine equipped with multiple mobile die stations to obtain metal elements, with the features described in the main claim.

The dependent claims describe advantageous embodiments of the invention. The main advantage of the invention is due to the fact that each station is equipped with a multiple die carriage which allows several pieces to be machined successively in the same station.

This makes it possible for the piece to be alternately outside the hydraulic, mechanical or other type of press so that it is no longer necessary for the punch unit to be raised beyond the height of the piece to be pressed in the die. The productivity of the multistation press is therefore constant when the diameter and shape of the pieces to be machined is the same, regardless of their length, thus obtaining products with a length of 1 ,000 mm and more without this ever being a limit in terms of performance.

This also means that the height of the press is much more limited compared to traditional systems, with all the consequent practical advantages especially as regards the capacity of the containing structures of these machines and therefore the cost of the system.

The machine for obtaining metal elements according to the invention envisages the sequence pressing of crop ends by means of their progressive insertion in several work stations and more precisely in several dies positioned on a carriage that moves alternately and transversally with respect to the relative station so that each piece can be machined alternately to other pieces in the same station.

From one station to the next each piece is alternately extracted and transferred by means of mechanical arms that rotate 180° to transfer the piece from the upstream position to the downstream position with respect to the feed line.

In cases of high productivity of the mύltipresses, product transfer can advantageously be carried out mechanically, pneumatically or with other systems by means of a transfer that envisages a buffer of semifinished products between one press and the next in order to minimise the movements of the grippers that move the products from one press to the next.

The carriage that holds the dies can move from one position to the next by means of a specific mechanical, hydraulic or other type of mechanism.

The use of the press with multiple die stations together with the rapid machining unit allows a high level of productivity that can reach production of a finished piece approximately every 3-4 seconds, regardless of the pressing diameter and above all of the length of the product which can be up to 1 metre and over without this ever representing a limit of the maximum productivity of the press. The die-holder unit movement system allows the new press model to house the product extraction, insertion and transfer systems outside the pressing area with considerable advantages for adjustment and maintenance operations of these systems as they are easily accessible to the operator and not, as with traditional machines, below, above or at the side of the press-holding structure in positions with difficult access.

In the event of drilling or punching, a lower ejection system is advantageously foreseen which acts in correspondence with holes already present in the die for the ejection movement normally carried out outside the pressing area.

Another undoubted advantage is the possibility of rapidly changing the equipment contained in the multiple die unit which can advantageously be entirely replaced with other equipment previously prepared externally so as to minimise machine down time. This system makes it possible to reduce die changes on the multipress by over . 1/3 with respect to a line of traditional fixed die presses.

DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will become evident on reading the following description of one embodiment of the invention, given as a non-binding example, with the help of the attached drawings in which: figure 1 is a schematic view of an example of a semifinished piece in the progressive machining stages on a traditional multipress machine, in which the successive stages are indicated with the letters from A to F; figure 2 shows a plan view of a multipress machine with multiple die stations according to the invention with the die unit in the rapid change position; - figure 3 represents an elevated front view of one of the stations of the machine according to the invention equipped with a multiple die carriage with the die unit in the rapid change position; figure 4 is a schematic front view of a machine positioned in the two operating stages; figure 5 is a schematic plan view of a machine with multiple die stations in an example of the progressive operating stages; figure 6 is a schematic view of one of the stations of the machine with the multiple die carriage in the first operating stage; figure 7 is a schematic view of the same machine as in the previous figure but in the second operating stage; figures 8 and 9 are schematic views, front and axonometric respectively, of the machine according to the invention.

DESCRIPTION OF ONE EMBODIMENT OF THE INVENTION . The press unit equipped with multiple die stations according to the invention, suitable for producing metal elements or manufactured products such as, for example, bushings, nuts or other elements with blind or through holes, screws, extruded or pressed products with standard and special shape, consists, as can be seen in figure 3, of a hydraulic, mechanical or other type of press 11 positioned on vertical columns 12 fixed on a bed 13, designed to give the press the possibility of vertical movement.

In accordance with the invention, a sliding carriage 14 is positioned close to the bed 13 of each station 10 and is equipped with a number of housings or dies, in this case two, indicated by 15 and 16, each of which can contain respective pieces being machined, indicated by 17 and 18.

A carriage 14 is therefore present on the bed 13 and moves alternately from one of the two machining positions of the pieces 17 and 18 below the press 1 1 to the other position.

More specifically, as can be seen frontally in figure 4 and in a plan view in figure 5, the carriage 14 can move from a position in which the first die 15 containing the piece 17 is below the press, to a second position in which the second die 16 holding the second piece 18 is below the same press.

It can be seen from figure 4 that in one case or the other one of the two pieces is outside the pressing area, meaning that while the piece is in this position the lower 19 and upper 20 insertion and extraction systems can intervene, working in conjunction with appropriate • grippers to transfer the product to the next presses. At the same time, the mechanical arm with the product coming from the previous operation positions the product and the upper insertion system then inserts the piece in the die. As can be seen in figure 5 the letters M, N, O, and P indicate four stations forming a multipress machine. Each of these stations includes a press 10 and a bed 13 equipped with a carriage 14 with the respective dies 15 and 16.

In the first station M, the carriage 14 with the dies empty is in the lefthand position and the mechanical arm can position a piece and the insertion system can insert the piece to be machined in the lefthand die 15, leaving only the part which has to be pressed on the outside, while the empty righthand die 16 is below the press.

The carriage is now moved towards the right so that the piece contained in the lefthand die 15 can be positioned below the press and the empty righthand die 16 can move to the open area on the right of the press where a second mechanical arm places another product in position and the insertion system inserts a second piece in this die.

At the same time, the presses carries out the pressing of the piece contained in the first die 15.

Once the piece has been loaded into the righthand die 16 and the piece in the lefthand die 15 has been pressed, the carriage moves towards the left to return to its original position so that after the enabling of the lower extraction system the lefthand mechanical arm can pick up the machined piece and move it into position for subsequent insertion by the upper system in the die of the next carriage in station N, which includes two dies and a respective press configured for the second machining stage.

While the machined piece is extracted from the die 15 in the first station, the piece in the righthand die 16 is machined and another piece is loaded into the lefthand die 15. Once the piece in the righthand die 16 has been machined, the carriage moves to the right again so that the piece in the die 16 can be extracted and the new piece in the die 15 can be machined.

This operating procedure continues for all the successive stations, each of which comprises dies with progressively different shapes, until the piece is complete.

In actual fact, a multipress machine according to the invention comprises a plurality of stations 10 each being equipped with a carriage with the same number of multiple dies, while at the sides of the stations there are at least two loading and unloading lines, one per side, for the movement of the pieces which proceed as far as the last machining stage by the station P.

There can, obviously, be any number of stations, just as there can be any number of dies . for each carriage 14, and if the carriages are equipped with more than two dies then the loading and unloading line of the lower extractors and the upper inserters and of the mechanical arms must be appropriately dimensioned and structured.

The dies in each carriage can also be different from each other to satisfy a wide range of production processes. As can be seen, the machine described here can solve four main innovative functions: - the increase in productivity of a multipress machine, due to the presence of multiple dies for each station and each press; the advantageous reduction of the stroke height of each press, since each piece can be loaded and unloaded outside the machine and the press stroke is only slightly greater than the piece compression stroke. the advantageous reduction of the tool change time when the product to be pressed changes in shape, diameter and length. easier adjustment operations during the machining process and easier maintenance by the operator since the piece extraction, insertion and transfer systems are all outside the pressing area. The machine according to the invention also makes it possible to cover a vast range of products regardless of their length, since piece extraction and insertion does not take place under the press but externally.

This also allows another extremely advantageous aspect to be fulfilled, since as the grippers of the mechanical arms and the insertion and extraction devices are outside the pressing area, they are no longer subjected to any interference with the press, thus resolving all the relative problems.

A further advantage offered by the machine according to the invention concerns the fact that positioning the piece insertion and extraction system outside the pressing area makes it possible to reduce the time necessary to carry out these stages. In traditional machines, in fact, the times for piece insertion and extraction below the press accounted for up to 50% of the overall machining times.

According to the invention, the die-holder beds, i.e. the carriages 14, can be replaced during the Working cycle with other die-holder carriages of a different type and shape, with the possibility of varying the working cycles simply and rapidly.

This possibility is due to that fact that the carriages can be mounted on bushings, sliding blocks or rails to move along two different lengths: the first length is shorter, being determined by the normal working cycle between one die and the other which move with respect to the press, while the second length is determined by the carriage replacement stages, where the stroke is longer as the carriage must be fully extracted from its housing. The piece insertion system will also be advantageously designed so that for particular reasons, such as for example in the event of breakage of the equipment in just one station of the carriage, it is possible to easily extract just one die without having to move the entire carriage to extract them both.

To move the pieces from one press to another, the mechanical arms for the transfer of the pieces from, one station to the next use transfer units that can consist of a series of steel grippers connected together and driven by a hydraulic, mechanical or compressed air device depending on the weight of the pieces to be transferred.

The individual grippers can transfer the piece from one station to the next and, if required by the pressing cycle, can also rotate the piece as necessary during the transfer.

The individual stations of the multipress with multiple die stations can be equipped with an extraction unit either in the lower part close to the bed, or near the pressing cylinder. This extraction unit can consist of small hydraulic, mechanical or other type of linear actuators. This extraction system can also be advantageously positioned below the pressing station in the event of punching or drilling of the product to be machined by hydraulic, mechanical or other types of presses.

The functioning and synchronisation of the individual presses and of the transfer unit are advantageously controlled and adjusted by a PLC.

In some cases, instead of moving laterally with respect to the relative press the multiple die carriage can move radially with respect to the single press positioned in the centre of a carousel machining unit.

The invention is described above with reference to a preferred embodiment. It is nevertheless clear that the invention is susceptible to numerous variations that are within its scope, in the framework of technical equivalents.

It is however clear for the technical expert that the system described above can easily be adapted to obtain full pieces such as screws, specially shaped extruded or pressed products, and all standard shaped extruded or pressed products, whether drilled or punched, according to machining requirements, which follow the construction specifications dictated by the various international regulations for fasteners or fixing systems, such as for example the DIN, ISO, ASTM, ANSI/ASME, JIS, SAE GB-GB/T regulations, etc., in general, for any mechanical element that can be cold, semi-hot or hot pressed or extruded according to a drawing provided by the client and with diameters indicatively greater than 16 mm with lengths indicatively greater than 200 mm up to 1 ,000 mm and over.

Claims

1. A press unit (10) for obtaining manufactured metal products, such as for example bushings, nuts or other elements with blind or through holes, screws, standard and specially shaped extruded or pressed products, said unit (10) consisting of a hydraulic and/or mechanical and/or other type of press suitable for machining metal, characterised in that close to the said unit (10) is at least one carriage (14) sliding on a bed (13) which is equipped with at least two dies (15, 16), each of which is designed to contain respective pieces to be machined (17, 18) and in that said carriage comprises movement means in order to transfer the pieces to be machined from a position below the punch of the press to a position away from the punch and vice versa.

2. A press according to the foregoing claim, characterised in that the carriage (14) can move from a position in which a first die (15) containing a piece (17) is positioned below the press punch, to a second position in which the second die (16) containing the second piece (18) is positioned close to the punch of the same press.

3. A press according to the foregoing claims, characterised in that during the machining stages at least one of the two pieces (17, 18) is outside the pressing area, where means are foreseen for the extraction of the piece and its subsequent pick-up and transfer by means of mechanical devices (19, 20) equipped with piece gripping, extraction and insertion means.

4. A press according to the foregoing claims, characterised in that it comprises a special system for piece extraction while the piece is outside the pressing area, and for pick-up and transfer of this piece, by means of at least one mechanical arm (19), equipped with appropriate gripping means, and in that it comprises a piece insertion system which, once the piece has been extracted from the die, can insert the product transferred by the mechanical arm of the previous press.

5. A press according to any of the foregoing claims, characterised in that the carriage with at least two dies is equipped with linear translation or rotation movement around one axis of the press.

6. A press according to any of the foregoing claims, characterised in that the carriage is mounted on bushings, sliding blocks or rails to move along sections of different lengths, in particular a first shorter length determined by the normal machining cycle between the dies which move with respect to the press, and a second longer length determined by the carriage replacement stages, as the carriage has to be fully extracted from its housing.

7. A press according to the foregoing claims, characterised in that the height of the press (11) is limited to the actual piece ^■pressing stroke.

8. A press according to the foregoing claims, characterised in that any number of dies can be associated with each carriage (14), and if the carriage is equipped with more than two dies, the loading and unloading line of the mechanical arms is appropriately structured.

9. A press according to any of the foregoing claims, characterised in that the dies of each carriage (14) can be different to each other to satisfy the most diverse production processes.

10. A press according to any of the foregoing claims, characterised in that it is the multistation type.

11. A press according to claim 10, characterised in that the work stations are arranged consecutively along a piece machining line and in that it comprises systems for the transfer of the pieces from one station to the next.