| JP2000167629 | DIE FOR PRESS WORK |
| JP2000094199 | PLASTIC WORKING APPARATUS |
| JP2002361497 | DIE MOVING TYPE PRESS FORMING MACHINE |
OLDOFREDI, Giuseppe (Via Solitro 20, Salò, I-25087, IT)
MESCHINI, Francesco (Via Pomaro 16, Gussago, I-25064, IT)
OLDOFREDI, Giuseppe (Via Solitro 20, Salò, I-25087, IT)
| CLAIMS 1. Machine for the hot-pressing of metal articles, especially in brass or aluminium, comprising a casing (10) bearing a die-holder slide (12) and an operating actuator (16) able to move said slide (12) along a vertical axis (X) between a raised inactive position and a lowered position in which the die is closed, and, at the base of the casing, a support bench (18) of the equipment (20, 21) needed to perform pressing of the articles, where said equipment comprises punches for making holes in the article to be pressed, and where the machine also comprises punch control actuators (40, 50) to move said punches between a rearward inactive position and a forward position, wherein said punches co-operate with the die to make said holes, the machine being characterised by the fact that said punch control actuators (40,50) can be operated independently of the movement, of the die-holder slide (12) . 2. Machine according to claim 1, wherein said punch control actuators (40, 50) can be independently operated so as to allow them to interact with the die at different times . 3. Machine according to any of the previous claims, wherein the punches (22) are mounted on respective punch- holder cars (24), each connected to a control actuator (40) moving the punches in a direction perpendicular to the movement axis (X) of the die-holder slide (12) . 4. Pressing machine according to claim 3, wherein said punch control actuators (40) can be moved vertically by means of respective release actuators (42) between a lowered position in which the equipment is engaged in the punch-holder cars and a raised, disengaged position allowing translation of the equipment. 5. Pressing machine according to claim 3, wherein the punch holder cars (24) and relative control actuators (40) are connected to each other by means of complementary coupling portions reciprocally blocked by a removable blocking pin (43) . 6. Pressing machine according to any of the previous claims, comprising a punch control actuator (50) having a thrust-stem (51) movable in a direction parallel to the movement axis of the slide (12) so as to project through an aperture (52) made in the support bench (18) and push upwards a floating punch inserted in the lower die (15) of the die to make a lower hole in the article to be pressed, said punch control actuator (50) being controllable independently of the other control actuators (40) . 7. Pressing machine according to any of the previous claims, wherein said punch control actuators (40, 50) are hydraulic cylinders. 8. Pressing machine according to claim 7, wherein said hydraulic cylinders are fitted with a programmable mechanical control (46, 56), for example with motorised transmission, which enables adjustment of their stroke to the size of the die. 9. Pressing machine according to any of the previous claims, wherein the operating actuator (16) of the die- holder slide (12) is a hydraulic cylinder. 10. Machine according to claim 9, wherein said operating actuator (16) is provided with stroke adjustment devices (180) programmable in relation to the size of the die or matrix so as to reduce the distance between the upper die (14), in the lower dead centre position, and the lower die (15) . 11.' Machine according to any of the previous claims, wherein the equipment support bench (18) extends horizontally also outside the casing, from opposite sides of it, so as to define a workstation (A) inside the casing, able to receive functioning equipment, and two standby stations (B,C), outside the casing, said bench having a translatable equipment support surface (26) so as to contemporarily transfer first equipment from the workstation to a standby station and second equipment from the other standby station to the workstation. 12. Machine according to claim 11, wherein said translatable support surface (26) is in the form of a table sliding on guides (28) attached to the frame of the bench. 13. Pressing machine according to claim 11 or 12, wherein each standby station (B,C) has preparation and/or test devices able to prepare the equipment in standby so that it is immediately utilisable as soon as it reaches the workstation and/or to simulate the pressing operation and/ or the lubrication operation. 14. Pressing machine according to claim 13, wherein each standby station (B, C) comprises a lift (30) able to block and raise the upper die (14) of the die of the equipment in standby. 15. Pressing machine according to claim 14, wherein said lift (30) comprises a die-holder slide (32) controlled by a dedicated actuator (34) and fitted with automatic coupling means (36) to the upper die (14). 16. Pressing machine according to any of the claims 13- 15, wherein said preparation devices comprise heating devices, for example electric or gas-powered, able to perform pre-heating of the die. 17. Pressing machine according to any of the claims 13- 16, wherein the test devices comprise means of control of mobile punches (22) of the equipment in standby. 18. Method of hot-pressing metal articles, especially in brass or aluminium, by means of a pressing machine according to any of the previous claims, wherein the vertical movement of the die-holder slide and the movement of the punch control actuators of the workstation are independent.. 19. Method according to claim 18, wherein the punch control actuators can be independently controlled. 20. Method according to claim 19, wherein the punch control actuators are operated in different instants so as to introduce the respective punches into the die in different instants. 21. Method according to any of the claims 18-20, wherein, while the machine performs at least one pressing cycle of an article with first equipment in the workstation, second equipment is placed in one of the two standby stations and is prepared and/or tested so as to be ready to replace the first, and wherein, at the end of said pressing cycle, the equipment support bench is commanded to translate to bring the first equipment to the other standby station and the second equipment to the workstation. 22. Method according to the previous claim, wherein the equipment contains one die or matrix. 23. Method according to claim 22, wherein the first and/or second equipment also comprises at least one punch supported by a respective punch-holder car for the realisation of at least one hole in the article to be pressed. 24. Method according to claim 22 or 23, wherein the preparation and/or test phase of the equipment in standby comprises a phase of coupling and raising the upper die of the die using a lift. 25. Method according to any of the claims 21-24, wherein the preparation and/or test phase of the equipment in standby comprises a phase of pre-heating the die. 26. Method according to any of the claims 21-25, wherein the preparation and/or test phase of the equipment in standby comprises a phase of moving the punches of the equipment in standby aimed at setting the strokes of said punches. |
"Machine for the hot-pressing of metal articles"
[00.01] The present invention relates to a machine for the hot-pressing of metal articles, especially articles in brass or aluminium.
[0002] As is known, a machine of this type comprises a casing bearing a die-holder slide and , an operating actuator able to move said slide along a vertical axis between a raised inactive position and a lowered position in which the die is closed. At the base of the casing there is a support which the equipment needed to perform the pressing of the articles starting from billets of metal in a semi-solid state, in other words at a temperature such as to permit plastic deformation of the same, is placed on. In the case of pressing articles with holes, the equipment comprises mobile punches borne on respective punch-holder cars. The equipment support is fitted with control actuators of said cars. Such actuators are in turn operated by a toggle lever or by other devices moved by lowering the die-holder slide onto the equipment. To such purpose, the equipment support is configured to oscillate vertically at each stroke of the press.
[0003] The movement of the mobile punches is therefore strictly related to the vertical movement of the die- holder slide, and all the punches act contemporarily on the article to be pressed.
[0004] In some cases, the metal pressed contemporarily by the punches does not reach all the parts of the die in a uniform manner, or produces burrs which must be removed in subsequent processing. The use of excess material to offset the non-uniform filling of the inner cavity of the die is, in addition, cause of a significant increase in production costs given the high incidence of the cost of raw material on the finished piece.
[0005] When a pressing cycle is completed, the upper die is released by the slide and all the equipment is removed from the machine. Before starting on a new cycle, a whole series of operations must be performed on the equipment, such as, for example, cleaning the equipment, replacing the die, repairing or replacing any worn parts, testing, pre-heating the die etc.
[0006] These operations take considerable time, so that between one cycle and the next several hours may elapse. In other words, therefore, unlike the machines for cold- pressing, hot pressing is characterised by very long and laborious operations to change the equipment.
[0007] This production method may become unsustainable when productions lots are small and the machine needs to be stopped frequently, for example to change the die, as happens increasingly often. In some cases, the stage may even be reached in which the pressing machine is inactive for more time than it is active.
[0008] The need to reduce the downtime of hot pressing machines is therefore increasingly felt.
[0009] The purpose of the present invention is to propose a machine and method for hot-pressing metal articles, especially in brass or aluminium, which overcomes the drawbacks mentioned above in relation to the prior machines.
[0010] Said purpose is achieved by a hot-pressing machine according to claim 1, and by a pressing method according to claim 19.
[0011] The characteristics and advantages of the machine and of the pressing method according to the present invention will however be evident from the description below of their preferred embodiments, made by way of a non-limiting example with reference to the attached drawings, wherein:
[0012] - figure 1 is a perspective view of the machine;
[0013] - figure 2 is an elevated view of the machine;
[0014] - figures 3-7 show the machine in the same number of phases of an equipment changing cycle;
[0015] - figure 8 is a ground view from above of the equipment support bench with two sets of equipment in a first position;
[0016] - figure 9 is a similar view to the previous, after a translation of the support bench;
[0017] - figure 10 shows, in partial cross-section, a pressing machine according to the invention in one embodiment variation;
[0018] - figure 11 is a perspective view of the workstation of the machine without the support bench of the machine equipment;
[0019] - figure 12 is an enlarged view of the support bench of the machine equipment, outside the workstation;
[0020] - figure 13 is an enlarged view of a control actuator of a punch-holder car;
[0021] - figure 14 is an enlarged view of a control actuator of a lower floating punch; and
[0022] - figure 15 is an enlarged view of the stroke adjustment devices of the die-holder slide.
[0023] With reference to the figures, reference numeral 1 globally denotes a machine for the hot-pressing of metal articles, especially in brass or aluminium.
[0024] The machine comprises a casing 10 bearing a die- holder slide 12 able to support an upper die 14 and an operating actuator 16 able to move said slide 12 along a vertical axis X between a raised inactive position and a lowered position in which the upper die 14 is closed on a lower die 15. The slide 12 with the die coupled to it, the operating actuator 16 and the equipment bearing the lower die constitute the main components of the press of the pressing machine.
[0025] At the base of the casing 10, the machine comprises a support bench 18 of the equipment 20, 21 provided to perform pressing of the articles. In the simplest case, said equipment 20 includes only the die, or matrix 14-15. In other cases, for example when the article to be pressed has holes, said equipment 21 comprises, as well as the die, punches 22 for making the holes, supported by relative punch-holder cars 24. Such equipment is also known as "punching equipment".
[0026] Innovatively, the equipment support bench 18 extends horizontally also outside the casing 10, from opposite sides of it, so as to define a workstation A inside the casing, able to receive functioning equipment, and two standby stations B, C, outside the casing. Said standby stations are able to receive second equipment to transfer to the workstation A, such second equipment being new equipment or equipment coming from the workstation itself, for example to undergo servicing. To such purpose, the equipment support bench 18 has an equipment support surface which translates horizontally so as to allow the contemporary transfer of first equipment from the workstation A to a vacant standby station B, C, and of second equipment, placed in standby in the other standby station B, C, to the workstation A.
[0027] In other words, while one of the two standby stations B, C, supports equipment 20, 21, the other is vacant so as to be ready to receive the equipment coming from the workstation A.
[0028] According to one embodiment, the translatable support surface is in the form of a table 26 sliding on guides 28 attached to the frame of the bench 18. Clearly, the length of said table 26 is less than the overall length of the support bench 18, so as to allow alternate movement of the table along said bench to move each group of equipment to the adjacent station.
[0029] According to one particularly advantageous embodiment, each standby station B, C has preparation and/or test devices able to prepare the equipment in standby so that it is immediately utilisable as soon as it reaches the workstation A and/or so that it is able to simulate the pressing operation, especially in the case of punching equipment 21, and/or simulate the lubrication operation.
[0030] According to a preferred embodiment, each standby station comprises a lift 30 able to block and raise the upper die 14. For example, said lift 30 comprises a die- holder slide 32 controlled by a dedicated actuator 34. In one embodiment, the slide 32 is fitted with automatic coupling means 36 to the upper die 14.
[0031] In one embodiment, the upper die 14 is fitted with blocking pins 14' suitable for inserting in respective seats made in the slide, and said automatic coupling means 36 comprise horizontal axis barrels 37 able to act as locks blocking the pins 14' of the die 14.
[0032] Advantageously, said lift 30 with slide 32 and automatic coupling means 36 simulates the die-holder slide 12 of the actual press, so as to check if any adjustments of the equipment are needed before transferring it to the workstation. In particular, the same automatic coupling system 36, 37 is also present on the die-holder slide 12 of the press. This way, after the sliding table has brought the two overlaid upper and lower dies, that is the closed die, inside the press, the slide 12 lowers into contact with the die and the pins 14 1 of the upper die 14 slot into their respective seats in the slide. The action of the blocking barrels 37 fastens the upper die 14 to the slide 12. Consequently, the presence of the attachment system of the die-half described above in the machine permits the automatic replacement of the dies.
[0033] Advantageously, the preparation devices comprise heating devices, for example electric or gas-powered, able to perform pre-heating of the die.
[0034] The lift 30 thereby enables, for example, both the replacement of the die and the raising of the upper die so as to introduce the heating device between the two open die halves.
[0035] Moreover, the test devices may comprise means of control of the mobile punches 22 making it possible to set the strokes of said punches.
[0036] In a preferred embodiment, the workstation A is fitted with actuators 40 to control the punch-holder cars 24 of the equipment 21 for making holes in the article to be pressed. Such actuators 40 act on the punch-holder cars 24 so as to move them between a rearward inactive position and a forward position, in which the punches borne on said cars co-operate with the two die-halves to press an article with holes.
[0037] Advantageously, the punch control actuators 40 are hydraulic actuators. This way, the control of the punches is mechanically independent of the movement of the die- holder slide 12, even though synchronised with it, significantly simplifying the structure of the machine. Such technical solution also makes it possible to avoid any vertical movement of the equipment in the workstation as happens in the machines of the prior art, in which the equipment needs to be lowered to control, for example by means of a toggle lever, the horizontal movement of the punch-holder cars. Consequently, the equipment support table can be made using a single and continuous translatable table 26.
[0038] According to one embodiment, the punch control actuators 40 can be moved vertically by means of respective release actuators 42 between a lowered position in which the equipment is engaged in the punch- holder cars and a raised, disengaged position allowing translation' of the equipment.
[0039] For example, said release actuators are attached vertically to the casing 10, in such a position as not to interfere with sliding of the .support surface and of the equipment placed thereon.
[0040] In one embodiment variation shown in figures 10-12, the punch holder car 24 and relative control actuators 40 are connected to each other by means of complementary coupling portions reciprocally blocked by a removable blocking pin. For example, the punch-holder cars 24 have a rear portion 24' which is C-shaped so as to couple with a counter-shaped front portion 40' of the control actuator 40. Said complementary coupling portions 24', 40' have respective aligned through holes 24, 45 for example parallel to the X axis of the press, which the removable blocking pin 43 can be inserted in. Advantageously, as the die-holder slide rises, it raises the blocking pin 43, for example by means of magnetic devices, so as to disengage the rear portion 24' of the punch-holder cars 24 from the front portion 40' of the control actuators 40. Preferably, moreover, the blocking pin 43 is retained in the hole 25 of said rear portion 40' .
[0041] In any case, the die 14, 15, the punch-holder cars 24 with relative punches 22 and any blocking pins 43 associated with said punch-holder cars 24 remain attached to the sliding table 26 so as to be brought to the standby stations B, C. Consequently only the control actuators 40 remain in the workstation A.
[0042] The pressing machine illustrated in figures 1-9 is provided with four punch-holder cars 24 orientated radially, in other words perpendicular to the movement axis X of the slide, so as to make, depending on the presence and number of punches 22 fitted on such cars, one or more lateral holes in the part to be pressed.
[0043] According to one advantageous embodiment shown in figures 10-14, the pressing machine is able to make a further hole on a parallel axis to the X axis, on the opposite side of the die-holder slide. To such purpose, in the workstation A the pressing machine has a base which houses a fifth control actuator 50, such as a hydraulic cylinder, having a thrust-stem 51 suitable for projecting through an aperture 52 made in the support bench 18 in the position of the lower die 15, when the same is in the workstation A. A floating punch (not shown) is inserted in the lower die 15, suitable for being pushed upwards by the thrust-stem 51 to make a lower hole in the part to be pressed. When the thrust- stem 51 is not activated and is therefore in a lowered rest position, the floating stem returns and it too remains in a lowered, rest position.
[0044] According to one advantageous embodiment, in addition, all the control actuators 40, 50 of the punches are hydraulic cylinders provided with a programmable mechanical control 46, 56, for example with motorised transmission, which enables adjustment of their stroke to the size of the part being produced.
[0045] This way, the performance of the hydraulic cylinders 40, 50 can ' be optimised for each part, shortening the operation time and consequently the volume of oil needed, thereby reducing the power demand of the pumps.
[0046] According to one advantageous embodiment, the operating actuator 16 of the die-holder slide is a hydraulic cylinder. More specifically, the operating actuator 16 comprises a movement hydraulic cylinder 162, powered by a pressurised fluid to translate the die- holder slide 12 between the two positions of the die open and the die closed, a hydraulic clamping cylinder 164, operatively connected to the movement cylinder 162 and powered by a pressurised fluid independently of said movement cylinder to create a clamping or closing force needed to counter the tendency of the die to open during the pressing phase, and thereby to prevent the backward movement of the die-holder slide 12, and a contrast unit 166 comprising means able to position themselves between a reaction structure, such as the upper part of the casing 10 or machine frame, and the clamping hydraulic cylinder 164, when the slide is in the closed position. Such contrast unit thereby prevents the possibility of upward translation of the slide under the effect of the clamping and reaction forces during the pressing phase.
[0047] In one embodiment, the clamping cylinder 164 is attached to the free extremity of the stem of the movement cylinder 162.
[0048] In one embodiment, the contrast unit 166 comprises a grooved ring 167 and, attached to the clamping cylinder 164, a cogged wheel or crown 168 able to slide inside said grooved ring 167 during translation of the clamping cylinder by the movement cylinder.
[0049] The grooved ring 167, controlled by a respective actuator 169, is rotatable between a phased position, in which there is a geometric coupling of the cogs on the crown or cogged wheel 168 and the grooves of the grooved ring 167, so as to enable shifting of the cogged wheel or crown and thereby unobstructed shifting of the clamping unit 164, and an out of phase position, in which said cogs and said grooves are out of phase with each other blocking the movement of the clamping unit.
[0050] Advantageously, the use of this hydraulic actuator 16 ensures a constant clamping force throughout the pressing phase, unlike mechanical flywheel actuators, and at the same time entails energy savings. In fact, the movement of the die-holder slide is entrusted to an actuator 162 which needs only to perform the shift from the open position to the closed position of the die. Its cross-section is therefore limited and the quantity of fluid in movement is modest.
[0051] The contrast during the pressing phase is of the mechanical type; consequently the movement unit does not need to perform reactions entailing keeping the fluid under pressure.
[0052] The clamping cylinder 164 acts on the die-holder slide at a later stage. Preferably, the clamping cylinder always contains a certain quantity of fluid which is immediately ready for pressurising, thereby freeing the power supply unit of having to transfer large quantities n
of fluid.
[0053] According to one advantageous embodiment, the control actuator 16 of the die-holder slide 12 is also fitted with programmable stroke adjustment devices 180 depending on the size of the part to be pressed, and therefore of the die or matrix. In particular, said programmable adjustment devices comprise a worm transmission and screw nut 181 driven by a hydraulic motor 182 so as to reduce the distance between the upper die 14, in the lower dead centre position, and the lower die 15.
[0054] For each part it is therefore possible to optimise the effective stroke of the cylinder moving the slide, shortening operating time, the volume of oil needed and thereby the power demand of the pumps to a minimum.
[0055] An innovative aspect of the machine according to the invention is the fact of being provided with a special cycle making it resemble a fly press. It ' is thus possible to obtain flat figures which need high speed deformation with a final coining thrust (such as for example, door handle plates, synchronisers and figures of reduced thickness) . Fly presses are high impact machines since they instantly transform the potential and kinetic energy of the slide into energy for pressing the part. With the press according to the invention, impact deformations can be obtained by channelling the pressure of the accumulators into the hydraulic system.
[0056] The accumulators are pressurised recipients inside which an elastic membrane separates the oil from the nitrogen in the upper part.
[0057] The accumulators can supply the hydraulic system with pressurised oil instantly. Their use enables a reduction of system response times overcoming the inevitable inertia of the pumps.
[0058] The functioning of the pressing machine according to the invention will now be described. Figure 3 shows the machine with first equipment 21 in the workstation and the die-holder slide 12 lowered in a position in which the die is closed. The first equipment is, in the example shown, equipment for making holes, so one may observe the punch-holder cars 24 pushed into a forward position by the relative control actuators 40. In one of the two standby stations, the one on the right (B) of the casing in the drawing, second equipment 20 is positioned, for example of a different type, in this case simple die- holder equipment, without any punches for making holes. The two groups of equipment may however be of the same type, if necessary containing different dies. The second equipment is still closed, in other words the upper die is disengaged from the lift.
[0059] While the machine works with the first equipment, the second equipment undergoes testing. For example, the lift 30 blocks the upper die 14 with the automatic blocking devices 36 and raises it (figure 4) . In this phase other test or preparation operations may be performed, such as pre-heating of the die. It should be noted that the second standby station C is vacant.
[0060] When the first equipment needs to be substituted by the second, the release actuators 42 of the cars 24 are actuated so as to cause disengagement of the control actuators of the punch-holder cars from said cars. Such actuators 40 are raised in relation to the equipment. In this phase, the lift 30 of the standby station B lowers onto the second equipment and releases the upper die (figure 5) .
[0061] At this point the mobile table 26 may translate. Following such translation, the first equipment 21 is transferred to the standby station C which was vacant (the one on the left) , while the second equipment 20 moves into the workstation, ready for utilisation (figure 6) .
[0062] When translation has taken place, the control actuators 40 of the cars return to their starting position and the die-holder slide 12 grips and raises the upper die 14 (figure 7) .
[0063] At this point a new pressing cycle may commence with the second equipment. In the meantime, the first equipment, now in the standby station, can be repaired or have the die replaced.
[0064] When the pressing cycle of the second equipment is terminated, the above procedure is repeated, this time with translation of the table in the opposite direction (from left to right) . As a result, the first equipment, or new equipment, will be re-transferred to the workstation, while the second equipment is brought to the standby station (on the right) .
[0065] As emphasised in the introduction of this description, up until now the hot pressing of parts with holes by mechanical presses has had some limitations due essentially to the fact that the movement of all the punches is synchronised and related to the position of the die-holder slide.
[0066] The machine according to the invention, rather, is provided with hydraulic control cylinders of the punches, for example four lateral cylinders and one lower cylinder, able to move the part independently of each other and of the position of the slide. It should be noted that, depending on the part being manufactured, it may not be necessary to use all four lateral cylinders (for example only three punches are needed when manufacturing a T-connector, and therefore only three cylinders) . In the mechanical presses of the prior art this asymmetric configuration of the equipment causes unbalancing of the same and consequent distortion of the part (unwanted rounding or deformation) .
[0067] With the hydraulic press according to the invention rather, the equipment, in particular the die, is kept in a stable position whatever the number of lateral cylinders active, thanks to the closing action of the cylinder moving the slide.
[0068] This makes it possible to produce more or less complicated products optimising the flow of material inside the die, reducing the risk of distortion of the fibres of the material itself to a minimum.
[0069] Advantageously, the punch control actuators, by being independent of the movement of the slide and also of each other, can act on the part in a manner which is not perfectly synchronised but at different moments. This enables a reduction of the oversizing which must be removed in subsequent processing for the removal of shavings. In particular, while in traditional machines the contemporary introduction of the punches in the die sometimes leads to the production of incomplete figures, the independent introduction of the punches according to the invention enables an optimal flow of the material in ideal conditions for producing parts without flash and with complete figures. This particular expedient also makes for longer duration of the dies and a saving of material in that the differentiated operation of the punches makes it possible to press the material into the cavity of the die where an initial penetration of a greater stroke is required. In other terms, the independent introduction of the punches makes it possible to optimise and differentiate the strokes of the punches themselves, with consequent improved completion of the figures .
[0070] The action of the lower hydraulic cylinder 50 is significantly different from what has been possible to obtain, up to today, using mechanical presses. Currently in fact one can only make a hole having an axis parallel to the direction of movement of the slide by making a protuberance on the lower die. The lower hydraulic cylinder, if present in the machine according to the invention, is able not only to make a hole with an axis parallel to the direction of movement of the slide, but can move towards the part to make a hole of the desired depth.
[0071] The machine hereto described therefore offers the chance to use the control actuators of the punches in any configuration, enabling the user to resolve some of the technological problems related to the reduced versatility of mechanical presses and their equipment for making holes .
[0072] A person skilled in the art may, in order to satisfy contingent requirements, make modifications, adaptations and replacements of elements with others functionally equivalent to the embodiments of the machine described above while remaining within the sphere of the following claims. Each of the characteristics described as belonging to a possible embodiment may be realised independently of the other embodiments described.