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MOLDING MACHINE AND MOLDING METHOD

FIELD OF THE INVENTION

This invention relates to a molding machine and molding method, and, more particularly, it relates to a match-plate molding machine and a molding method using a match plate.

BACKGROUND OF THE INVENTION

One example of conventional match plate molding machines for molding upper and lower molds at the same time is disclosed in WO2005/058528 Al. In this molding machine, first, a match plate is sandwiched and held between a cope flask and a drag flask. Upper and lower squeeze members are then inserted into the respective flasks through their openings opposed to the match plate such that upper and lower molding spaces are defined. The defined molding spaces are then filled with molding sand. The upper and lower squeeze members are then moved to the match plate to squeeze the molding sand within the molding spaces to mold upper and lower molds. The cope and drag flasks, which contain the corresponding upper and lower molds, are then removed from the match plate. These removing procedures are achieved with cylinders that reciprocatingly move the cope and drag flasks relative to the match plate.

The inconvenience of such a conventional molding machine is that the procedures for removing the cope and drag flasks from the match plate start when the match plate adheres to either the upper mold or the lower mold. That is, if the match plate adheres to either mold, first, the other mold (i.e., the mold that doesn't adhere to the match plate) and the corresponding flask that contains the other mold, are removed (i.e., stripped) from the match plate in unison (the first stripping). Then one mold (i.e., the mold that adheres to the

match plate), and the corresponding flask that contains that one mold, are then removed from the match plate in unison (the second stripping). The first stripping is to be begun when the other mold is stationary. The second stripping should, however, be done when the moving match plate, which is moved immediately just before this point, is stopped, while the mold (the one mold) that is adhered to the match plate is still moving. Because of this, the one mold may receive a significant impact when it is removed from the match plate. Thus the second stripping may cause a defect.

Accordingly, one object of the present invention is to provide a molding machine and molding method that prevent any defect in a mold that is adhered to a match plate when it, and the corresponding flask that contains the mold, are removed from the match plate.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a molding method is provided. The method includes the steps of: holding a match plate between a cope flask and a drag flask; inserting an upper squeeze member and a lower squeeze member into the opening of the cope and drag flasks opposed to the match plate to define an upper molding space and a lower molding space, respectively; filling the defined molding space with molding sand? and driving the upper and lower squeeze members toward the match plate to squeeze the molding sand within the upper and lower molding space to mold an upper mold and a lower mold at the same time. The method is characterized in that it further comprises the step of: forcibly pushing away the cope and drag flasks that contain the molded upper and lower molds from the match plate at the same time when the flasks are stationary.

Preferably, the velocity at which the cope flask is separated from the drag flask is twice that when the match plate is separated from the drag flask,

and preferably the velocity at which the cope flask is separated from the match plate is the same as that when the drag flask is separated from the match plate.

In another aspect of the present invention, a match -plate molding machine is provided. It includes-' a cope flask and a drag flask; a match plate to be held between them; an upper squeeze member and a lower squeeze member that are insertable into openings of the cope and drag flasks, and which are opposed to the match plate; means for filling molding sand within an upper molding space that is defined by the cope flask, the match plate, and the upper squeeze member, and a lower molding space that is defined by the drag flask, the match plate, and the lower squeeze member; and driving means for driving the upper and lower squeeze members toward the match plate to squeeze the molding sand within the upper and lower molding spaces to mold an upper mold and a lower mold at the same time. The molding machine is characterized in that it further comprises ^* upper and lower pushing means for forcibly pushing away the cope and drag flasks that contain the molded upper and lower molds from the match plate when the flasks are stationary, wherein the upper pushing means and the lower pushing means are mounted on both the cope flask and the drag flask. Preferably, the upper pushing means is a hydraulic cylinder that is extended by oil therein. The lower pushing means is a hydraulic cylinder that has less force to supply the oil that was forced inside the cylinder than that of the upper pushing means, or is an air cylinder that is extended by the compressed air, or is an elastic means that is extended by an elastic member. In one embodiment of the present invention, the cope and drag flasks have sand-filling ports on their sidewalls for filling sand.

Preferably, the drag flask is mounted on a rotating frame, which is rotated downwardly and upwardly in a vertical plane. The cope flask is mounted on the rotating frame such that the cope flask can approach and retract from the drag flasks.

The molding machine may further comprise a shuttle for carrying in and carrying out the match plate between the cope and drag flasks. Also, it may further comprise a mechanism for the match plate to approach and retract from the drag flask. The molds from the match-plate molding machine of the present invention may to be tight-flask molds or flaskless molds.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other purposes and advantages of the present invention are further clarified by the following descriptions, which refer to the accompanying drawings, in which:

Fig. 1 is a front view schematically illustrating a molding machine of the present invention, ^' Fig. 2 is a schematic left view of the molding machine of Fig. L' and

Fig. 3 schematically illustrates a pressurizing fluidic unit that drives the molding machine of Figs. 1 and 2.

Fig. 4 schematically illustrates an alternative embodiment of the hydraulic power unit.

DESCRIPTION OF THE PREFERED EMBODIMENT OF THE PRESENT INVENTION

One embodiment of the match-plate molding machine of the present invention will now be explained in detail by reference to Figs. 1, 2, and 3. As shown in Figs. 1 and 2, the molding machine of the present invention includes a rotating frame 2, which is extended substantially vertically. The rotating frame 2 is pivotally mounted on a supporting shaft 1 such that it can be moved up and down in the vertical plane about the supporting shaft 1. A drag flask 4,

whose sidewall has sand-filling ports, is mounted on the lower end of the rotating frame 2 via a supporting member 3. On the left side of the rotating frame 2, a pair of guide rods 5 is attached at a predetermined interval therebetween in back and front such that they extend substantially vertically. On the guide rods 5, a match plate 7 is slidably and vertically mounted via guide holders 6. Immediately above the guide holders 6 of the guide rods 5, a cope flask, whose sidewall has sand-filling ports, is slidably and vertically mounted via guide holders 8. Attached to the left side of the rotating frame 2 is the distal end of a piston rod of a downwardly facing, vertical cylinder 10. The match plate 7 can be carried in and carried out between the cope flask 9 and the drag flask 4 by any well-known shuttle (not shown). The match plate 7 can be moved to approach and retract from the drag flask 4 by an upwardly-facing cylinder (not shown) that is mounted on the rotating frame 2, as it is extended and contracted. The cope flask 9 is mounted on a cylinder 10 such that it is moved upward and downward by extending and contracting operation of the cylinder 10 to approach and retract from the match plate 7. Mounted near the four corners of the outer periphery of the cope flask 9 are four downwardly facing hydraulic cylinders (upper pushing means) 11 for pushing away the cope flask 9 from the match plate 7. Similarly, mounted near the four corners of the outer periphery of the drag flask 4 are four, upwardly facing, air cylinders (lower pushing means) 12 for pushing away the drag flask 4 from the match plate 7.

As in Fig. 3, the molding machine is provided with a pressurizing fluidic unit 13 that supplies oil to the four hydraulic cylinders 11 and compressed air to the four air cylinders 12. The pressurizing fluidic unit 13 includes a hydraulic unit 14 having a hydraulic pump for generating the oil and a compressor 15 for generating the compressed air. The hydraulic pump of the hydraulic unit 14 is connected to an upper port and a lower port of a downwardly facing, hydraulic cylinder 16 through a directional control valve 17 and a shut-off valve 18.

On the lower end of the piston rod of the hydraulic cylinder 16, a pusher plate 19 is fixed. Below the pusher plate 19, four hydraulic pushers 21, for extruding and supplying the oil to respective upper ports of the four hydraulic cylinders 11 through four pipes 20, are provided such that their upper ends abut the pusher plate 19. Each of the hydraulic pushers 21 comprises an upwardly facing, hydraulic cylinder structure. The four pipes 20 are connected to the hydraulic pump of the hydraulic unit 14 through four respective shut-off valves 22. The respective lower ports of the four hydraulic cylinders 11 are connected to the hydraulic unit 14 through the directional control valve 17. The four air cylinders 12 are connected to the compressor 15 through a directional control valve 23.

With the foregoing molding machine, prior to the machinery state shown in Figs. 1 and 2, the match plate 7 is sandwiched and held between the cope flask 9 and the drag flask 4 at a molding station (not shown). Upper and lower squeeze members (not shown) are then inserted into the corresponding openings, which are opposed to the match plate 7, of the cope flask 9 and the drag flask 4, to define upper and lower molding spaces. The cope flask 9, the drag flask 4, the match plate 7, and their associated elements defining the molding space are then turned to their vertical positions or horizontal positions such that molding sand is blown and filled within the molding spaces through the sand-filling ports of the cope and drag flasks 9 and 4. The upper and lower squeeze members are then drivingly moved to the match plate 7 to squeeze the molding sand within the upper and lower molding spaces to make an upper mold and a lower mold at the same time. As a result, the molding machine is in the state shown in Figs. 1 and 2.

At the same time, the shut-off valve 18 is preliminarily opened to supply the oil to the lower port of the cylinder 16 and the upper ports of the four hydraulic pushers 21 to contract the cylinder 16 and to extend the four hydraulic pushers 21. The shut-off valve 18 is then closed and the four shut-off valves 22 are opened to supply the oil from the hydraulic pump of the

hydraulic unit 14 to the four pipes 20, and the lower ports of the four hydraulic pushers 21. The oil from the hydraulic pump is also supplied to the upper ports of the four hydraulic cylinders 11 to contract them. The four shut-off valves 22, which are located between the four pipes 20 and the hydraulic unit 14, are then shut off.

From the state shown in Figs. 1 and 2, the cylinder 10 is extended to raise the cope flask 9, while another cylinder (not shown) is contracted to raise the match plate 7. In this case, the velocity of the cope flask 9 when it rises is preferably twice that of the match plate 7. The directional control valve 17 is then turned to extend the cylinder 16 to contract the four hydraulic pushers 21 through the pusher plate 19 to supply the oil to the upper ports of the four hydraulic cylinders 11 to extend them. At the same time, the directional control valve 23 is turned to supply the compressed air from the compressor 15 to the four air cylinders 12 to extend them. Therefore, the four hydraulic cylinders 11 push down the match plate 7, while the four air cylinders 12 are simultaneously pushed up to the match plate 7. This causes the cope and drag flasks 9 and 4, which contain upper and lower molds, to be simultaneously pushed away from the match plate 7 and each other. In contrast to the conventional two-step stripping, the cope flask 9 and the drag flask 4 are thus stripping at the same time. Therefore, this prevents an undesirable impact that may cause a defect in a mold that is involved in the conventional second stripping (stripping one flask from the match plate on which a mold that is contained within the flask is adhered).

In this case, setting the velocity of the cope flask 9 when it is rising to twice that of the match plate 7 results in there being a sufficient space in which the cope and drag flasks 9,4 can be simultaneously pushed away from the match plate 7 and each other, in the following step.

While the molding machine and molding method of the present invention have been described with respect to the preferred embodiment, it is to be understood that the invention is intended to cover all of the various

modifications and variations that can be included within the spirit and scope of the appended claims. Accordingly, the arrangements and operations of the match-plate molding machine for which the present invention can be applied are not limited to those described and shown herein. For example, the match plate, the cope flask, and the drag flask may rotate after the match plate is held between the cope and drag flasks. Alternatively, the match plate may be held between the cope flask and the drag flask after the flasks are rotated. Therefore, the timing of holding the match plate and rotating the flasks does not limit the present invention. The resulting upper and lower molds that are made by the molding machine and molding method of the present invention may be tight-flask molds or flaskless molds.

Further, the hydraulic power unit 13 of the molding machine of the present invention is not limited to its embodiment shown in Fig. 3. The hydraulic power unit 13 of Fig. 3 may be replaced with, e.g., the alternative hydraulic power unit 13A of Fig. 4. The alternative hydraulic power unit 13A of Fig. 4 differs from the foregoing hydraulic power unit 13 of Fig. 3 in that the hydraulic cylinder 16 and the shut-off valve 18 are eliminated, while the upper ports of the hydraulic pushers 21 are connected to the directional control valve 17. Because the other elements of the alternative hydraulic power unit 13A of Fig. 4 are the same as those that are denoted by the same numbers of the hydraulic power unit 13 of Fig. 3, their explanations are omitted.

The operation of the molding machine that employs the alternative hydraulic power unit 13A will now be explained. First, the molding machine makes the upper and lower molds at the same time, in the same manner as in the foregoing embodiment. As a result, the molding machine is thus in the state shown in Figs. 1 and 2. The four shut-off valves are then opened to supply the oil to the four pipes 20 and the lower ports of the four hydraulic pushers 21. The oil is also supplied to the upper ports of the four cylinders 11, to contract them. The four shut-off valves are then closed to shut off the fluid communication between the four pipes 20 and the hydraulic unit 14.

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From the state shown in Figs. 1 and 2, the cylinder 10 is then extended to raise the cope flask, while the other cylinder (not shown) is contracted to raise the match plate 7. In this case the velocity of the cope flask 9 when it rises is preferably twice that of the match plate 7. The directional control valve 17 is then turned to contract the hydraulic pushers 21 through the pusher plate 19 to supply the oil to the upper ports of the four hydraulic cylinders 11, to extend them. At the same time, the directional control valve 23 is turned to supply the compressed air from the compressor 15 to the four air cylinders 12 to extend them. Therefore, the four hydraulic cylinders 11 push down the match plate 7, while the four air cylinders 12 push up the match plate 7. This causes the cope flask 9 and the drag flask 4, which contain the upper and lower molds, to be simultaneously pushed away from the match plate 7 and pushed away relative to each other. The cope flask 9 and the drag flask 4 are thus stripped at the same time, the same as in the foregoing embodiment.