PRESSURE DIE-CASTING MACHINE

Abstract: A pressure die-casting machine comprising, on a supporting frame (11) fixed to the ground, a casting assembly (12) associated with an injector assembly (13) and with extraction elements (14), the casting assembly (12) having two coupled dies (16, 19) which have, during closure, aligned directions and opposite orientations, and are adapted to produce optionally two synchronized castings. The two dies (16, 19) comprise a common intermediate complementary die portion (15) adapted to form, on mutually opposite faces, the half-shells (18, 21) related to each one of the two dies (16, 19), the intermediate complementary die (15) being fixed to the supporting frame (11) at least during a period of time that covers that of the casting operation.

Description: PRESSURE DIE-CASTING MACHINE TECHNICAL FIELD The present invention relates to a pressure die-casting machine. BACKGROUND OF THE INVENTION It is known that pressure die-casting machines that comprise, substantially, on a supporting frame that is fixed to the ground, a casting assembly associated with an injector assembly and with extraction means, are currently used to manufacture metal items, especially because of their economic advantages and their high productivity. The technology of these machines is now well-established and appreciated because it also allows to produce items that have a rather complex shape while ensuring an excellent end result in terms of precision and dimensional tolerances, as regards shape and position that are stable, even in large production runs. However, currently commercially available machines are particularly demanding in terms of space occupation and initial investment. The high pressures generated inside such machines must in fact be controlled appropriately by means of suitable systems associated with the merely mechanical movement system, which in itself is already rather complex. It is therefore evident that at present pressure die-casting machines are justifiable only in terms of production runs that can ensure an adequate return on the initial investment. DISCLOSURE OF THE INVENTION The aim of the present invention is to provide a pressure die-casting machine whose structure allows a significant increase in productivity without however causing a proportional increase in constructive complexity and in operating and investment costs at purchase. Within this aim, an important object of the present invention is to provide a machine whose structure allows in practice the simultaneous production of two parts with a single injection while maintaining the systems and the mechanical movements substantially similar or in any case equivalent, at least to a large extent, to those of single-casting machines. Another object of the present invention is to provide a machine whose structure ensures a better and higher ratio between productivity and floor surface occupation. Another object of the present invention is to provide a machine whose structure allows better overall payback of investments and a specific reduction, in terms of productivity, of management and operating costs. Another object of the present invention is to provide a machine that can be used easily even by personnel trained on conventional machines and can ensure high automation of the process and an increase in the average lifetime of the dies loaded onto it. Another object of the present invention is to provide a machine that can be manufactured with known technologies and at costs that are competitive with respect to similar commercially available machines. This aim and these and other objects that will become better apparent hereinafter are achieved by a pressure die-casting machine of the type that comprises, on a supporting frame, a casting assembly that is associated with an injector assembly and with extraction means, said machine being characterized in that said casting assembly has two coupled dies which have, during closure, aligned directions and opposite orientations, said dies being adapted to produce optionally two synchronized castings, said two dies comprising a common intermediate complementary die portion that is adapted to form, on mutually opposite faces, the half-shells related to each one of said two dies, said intermediate complementary die portion being rigidly coupled to said supporting frame at least during a period of time that covers that of the casting operation. BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics and advantages of the present invention will become better apparent from the description of an embodiment thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is a schematic view of a machine having the structure according to the invention; Figure 2 is a partially sectional orthographic projection view of a constructive detail of the machine of Figure 1; Figures 3 to 6 are partially sectional orthographic projection views of a portion of the machine of Figure 1 in various steps of its operation; Figure 7 is an orthographic projection view of part of an item manufactured by means of the machine of Figure 1; Figure 8 is a partially sectional orthographic projection view of another constructive detail of the machine of Figure 1; Figure 9 is a partially sectional orthographic projection view of another constructive detail of the machine of Figure 1; Figure 10 is a partially sectional orthographic projection view of a variation of the constructive detail of Figure 9; Figure 11 is a partially sectional orthographic projection view of a constructive detail of the machine of Figure 1; Figures 12 to 14 are partially sectional orthographic projection views of a same constructive detail of the machine of Figure 1 in various steps of operation; Figures 15 and 16 are partially sectional orthographic projection views of a same constructive detail of the machine of Figure 1 in various steps of operation. WAYS TO CARRYING OUT THE INVENTION With particular reference to Figures 1 to 16, a pressure die-casting machine according to the invention is generally designated by the reference numeral 10. In particular, the machine 10 comprises, on a supporting frame 11, a casting assembly, generally designated by the reference numeral 12, that is associated with an injector assembly, generally designated by the reference numeral 13, and with extraction means, generally designated by the reference numeral 14. The casting assembly 12 has two dies, described in greater detail hereinafter, which are coupled and have, during closure, aligned directions and opposite orientations and are suitable to produce optionally two synchronized castings. Said two dies comprise a common intermediate complementary die portion 15 that is suitable to form, on mutually opposite faces, the half -shells related to each one of said two dies. The complementary die portion 15 is rigidly coupled, as described in greater detail hereinafter, to the supporting frame 11 at least during a preset time interval that extends over or covers that of the casting operation. In particular, of said two dies, a first die 16 is constituted not only by a corresponding part of the complementary die portion 15, designated by the reference numeral 17, but also by a half-shell 18 that is fixed to the supporting frame 11. A second one of the two dies, designated by the reference numeral 19, is also constituted not only by a corresponding part of the complementary die portion 15, designated by the reference numeral 20, but also by a movable half-shell 21 that is associated with first actuation means 22. The first actuation means 22 is partially associated with the complementary die portion 15 so as to actuate it away from said fixed half- shell 18 after a preset time and space delay, with respect to the separation of the movable half -shell 21, with an orientation that corresponds to the spacing of said movable half-shell. The first actuation means 22 comprise, in this case, traction elements 23 that are coupled to the base 24 of the movable half-shell 21 and are slidingly inserted in the complementary die portion 15 and provided with a traction head 25 for said complementary die portion. The machine 10 also comprises temporary locking means for the complementary die portion 15, which is generally designated by the reference numeral 26 and is constituted by an engagement element 27 that is associated with second actuation means, generally designated by the reference numeral 28, which is synchronized with said first actuation means 22. In particular, the locking means 26 is constituted by a stem 29 which is arranged with a vertical axis and is suitable to enter, under the action of said second actuation means 28, a corresponding seat 30 formed in the complementary die portion 15 and engage therein. In particular, the stem 29 is arranged in an upward region with respect to the complementary die portion 15. The extraction means 14 comprises, for the second die 19, a first extraction set, generally designated by the reference numeral 31, which is constituted by multiple stems 32 (only one of which is visible in the figures) inserted in suitable holes 33 that are formed in said movable half-shell 21. The extraction means 14 for the first die 16 is constituted by a second set, generally designated by the reference numeral 34, which comprises multiple stems 35 (only one of which is visible in the figures) which are slidingly inserted in said fixed die portion 18 and have bases 36 that are coupled to a movable plate 37 that is connected to a first head 38 for engagement with a shaft 39 that can slide on bushes 40 recessed in the supporting frame 11 and is provided with a second head 41 that is coupled to a hydraulic or pneumatic actuator 42 with casting force recovery. In particular, the second set 34 also has adjustable spacer pins 43. In this embodiment, the complementary die portion 15 has an intermediate supporting core 44 on which impression plates 45 and 46 are coupled so as to form a corresponding number of half-shells for said two dies. In particular, the plates 45 and 46 are connected to the core 44 by means of pins 47. The injection assembly 13 comprises a duct 48 in which an injection piston 49 can slide; said piston is suitable for cropping, even at the end of the injection stroke, the end portion of the sprue 50 that relates to the part 51 formed within the first die 16 (the other part being designated by the reference numeral 52). In particular, the duct 48 has a surface for forming the conical outward- facing portion meant to improve the behavior of the pressure at the end of the thrust of the piston 49. The extraction means 14 also comprises, on a fixed support 53, two clamps 54, each with its corresponding articulated arm 55, which are coupled to movement means. The machine 10 is furthermore provided with cropping means, generally designated by the reference numeral 56, which has a movable surface 57 associated with two cropping units 58 and corresponding waste removal regions 59. In particular, the two clamps 54 and the corresponding articulated arms 55 are suitable to form a direct path between said two dies and said cropping means 56. With particular reference to Figure 10, in a constructive variation of the machine 10 the complementary die portion 15 is formed by two plates, designated by the reference numerals 60 and 61 respectively, which are mutually reversibly coupled so that each one has an outer face that forms the impression of a corresponding die. In particular, the two plates 60 and 61 are mutually connected by virtue of a reversible conical coupling, generally designated by the reference numeral 62, and are provided with seats 63 for the passage of the neutralization screws and seats 64 for the passage of the retention screws. In practice the operation of the present invention is as follows. Starting with the machine 10 fully closed and therefore during casting, the piston 49 lies in the end region of its stroke, in which it has pushed the molten material into the dies 16 and 19. Once this step has been performed, the machine 10 prepares for opening, which is provided by means of the following series of steps. Initially, the second die 19 opens and by retracting causes, after a space and time interval, the application of a traction force to the traction elements 23, which in turn pull and separate the complementary die portion 15 that up to that point was fixed, through the activated locking means 26, to the supporting frame 11. The complementary die portion 15 is then pulled open with respect to the first die 16, and at the same time the piston 49, moving beyond its normal stroke limit, breaks the sprue 50 of the part 51 related to said first die 16. Once both the first die 16 and the second die 19 are open, the extraction means 14, each in its own manner, produce the expulsion of the parts, which can be appropriately removed by means of the clamps 54 provided with articulated arms 55 that carry said parts into a region preset for the cropping means. At this point, the machine 10 can return to the closed state by virtue of steps that are fully symmetrical to what was described earlier for opening. However, it should be noted that during the end of the closure stroke the machine ensures optimum balancing of the thrusts, which by being mutually opposite in the closure of the two dies balance each other and ensure that it is possible to provide a double casting by using power levels and forces that are normally used for a single casting. Furthermore, if necessary it is possible to "neutralize" one of the two dies (typically the second one 19), so as to preset the machine 10 according to a "conventional" configuration. In practice it has been found that the present invention has achieved the intended aim and objects. In particular, it should be noted that the machine according to the invention allows a double casting which however is provided in a manner that is highly balanced in terms of forces and power levels involved. Furthermore, it should be noted that the particular shape of the machine according to the invention ensures, for said machine, in addition to great dynamic and static equilibrium, also the possibility of a considerable reduction of power in relation to the number of parts produced. In fact, in practice it is possible to perform two simultaneous castings with a power level and generated forces that are substantially similar to those related to a single casting. Nevertheless, and as mentioned, in particular application situations one die or the other can be appropriately "neutralized", thus returning the machine as a whole substantially to operating according to a more conventional method. Moreover, it should be noted that the structure of the machine according to the invention ensures high productivity while ensuring dimensions that are substantially similar to those of single-casting machines. All this results in considerable savings in terms of time and costs, which give the machine according to the invention one of the highest productivity/cost ratios. In particular, it should be noted that investment costs and operating and management costs have been reduced considerably. The machine according to the invention, despite being innovative, inherently still entails, in terms of management, procedures that are similar to machines of a more conventional type; therefore it can be used without excessive difficulty even by personnel trained on machines of the conventional type. Moreover, it should be noted that practical tests have shown an increase in the lifetime of the dies of the machine according to the invention, indeed in relation to its great dynamic balance. The present invention is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept. The technical details may be replaced with other technically equivalent elements. The materials and the dimensions may be any according to requirements. The disclosures in Italian Patent Application No. PD2000A000256 from which this application claims priority are incorporated herein by reference.

Claims: CLAIMS 1. A pressure die-casting machine of the type comprising, on a supporting frame (11), a casting assembly (12) that is associated with an injector assembly (13) and with extraction means (14), said machine being characterized in that said casting assembly (12) has two coupled dies (16, 19) which have, during closure, aligned directions and opposite orientations, said dies (16, 19) being adapted to produce optionally two synchronized castings, said two dies (16, 19) comprising a common intermediate complementary die portion (15) that is adapted to form, on mutually opposite faces, the half-shells (18, 21) related to each one of said two dies (16, 19), said intermediate complementary die portion (15) being rigidly coupled to said supporting frame (11) at least during a period of time that covers that of the casting operation. 2. The machine according to one or more of the preceding claims, characterized in that a first one (16) of said two dies is constituted not only by a corresponding part (17) of said intermediate complementary die portion (15), but also by a half-shell (18) that is fixed to the supporting frame (11). 3. The machine according to one or more of the preceding claims, characterized in that a second one (19) of said two dies is constituted not only by a corresponding portion (20) of said intermediate complementary die (15) but also by a movable half-shell (21) that is associated with first actuation means (22). 4. The machine according to one or more of the preceding claims, characterized in that said first actuation means (22) is associated with said intermediate complementary die portion (15), for actuation thereof away from said fixed half-shell (18) after a preset time delay with respect to the separation of said second die (19), with the same orientation as the direction in which said second die (19) moves away. 5. The machine according to one or more of the preceding claims, characterized in that said first actuation means (22) comprises at least one traction element (23), coupled to the base of said movable half-shell (21), slidingly inserted in said complementary die portion (15), and provided with a traction head (25) for said complementary die portion (15). 6. The machine according to one or more of the preceding claims, characterized in that it comprises temporary locking means (26) for said complementary die portion (15), said locking means (26) being constituted by an engagement element (27) that is associated with a second actuation means (28) that is synchronized with said first actuation means (22). 7. The machine according to one or more of the preceding claims, characterized in that said locking means (26) is constituted by a stem (29) that is arranged vertically, has a substantially vertical action, and is adapted to enter, upon action of said second actuation means (28), and engage a corresponding seat (30) formed in said complementary die portion (15). 8. The machine according to one or more of the preceding claims, characterized in that said stem (29) is arranged upward with respect to said complementary die (15). 9. The machine according to one or more of the preceding claims, characterized in that said extraction means (14) is constituted, for said second die (19), by a first extraction set (31) constituted by at least one horizontal stem (32) inserted in suitable holes (33) of said movable half-shell (21). 10. The machine according to one or more of the preceding claims, characterized in that said extraction means (14) is constituted, for said first die (16), by a second set (34) that comprises at least one stem (35), inserted slidingly in said fixed half-die (18) and have bases (36) that are coupled to a movable plate (37) connected to a first head (38) for engaging a shaft (39), which can slide on bushes (40) that are recessed in said supporting frame (11) and is provided with a second head (41) that is coupled to a hydraulic or pneumatic actuator (42) with casting force recovery. 11. The machine according to one or more of the preceding claims, characterized in that said second set (34) is provided with at least one adjustable spacer (43). 12. The machine according to one or more of the preceding claims, characterized in that said complementary die portion (15) is provided with an intermediate supporting core (44) on which impression plates (45, 46) are coupled, said plates (45, 46) being adapted to form a corresponding number of half-shells for said two dies (16, 19). 13. The machine according to one or more of the preceding claims, characterized in that said two plates (45, 46) are connected to the intermediate core (44) by means of pins (47). 14. The machine according to claim 1, characterized in that said complementary die portion (15) is constituted by two plates (60, 61) that are reversibly coupled to each other, each one having an outer face that forms an impression in a corresponding die. 15. The machine according to claim 14, characterized in that said two reversibly coupled plates (60, 61) are connected by way of a reversible conical coupling (62). 16. The machine according to claim 14, characterized in that the two reversibly coupled plates (60, 61) have seats (63) for the passage of neutralization screws and seats (64) for retention screws. 17. The machine according to one or more of the preceding claims, characterized in that said injection assembly (13) comprises an injection duct (48) in which an injection piston (49) can slide, said piston (49) being adapted for cropping, at the end of the injection stroke, the end portion of the sprue (50) related to said first die (16). 18. The machine according to one or more of the preceding claims, characterized in that said injection duct (48) has substantially conical surfaces forming its outer portion. 19. The machine according to one or more of the preceding claims, characterized in that said extraction means (14) comprises, on a fixed support (53), two clamps (54), which are associated with corresponding articulated arms (55) coupled to movement means. 20. The machine according to one or more of the preceding claims, characterized in that it comprises a cropping means (56) that is constituted by a movable surface (57) provided with two cropping units (58) and corresponding regions (59) for waste removal. 21. The machine according to one or more of the preceding claims, characterized in that said two clamps (54) and the corresponding articulated arms (55) are suitable to trace a direct path between said two dies and said cropping means (56).

Inventors: MORTARI GRAZIANO, MORTARI, GRAZIANO
Applicants: IDRA PRESSE S P A, MORTARI GRAZIANO, IDRA PRESSE S.P.A., MORTARI, GRAZIANO
Application year: 2001
Main classification: B22D17
IPC codes: B22D17