JP2500910Y2 - Sprue bar in mold making machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improved structure of a sprue bar in a mold making machine for forming a sprue in a mold when molding the mold.

(Background Art) Conventionally, as a type of mold making machine that compacts molding sand in a molding frame to mold a casting mold, a pattern plate integrally formed with a model is sandwiched between a pair of casting molds on both sides of the pattern plate. By stacking the frames (upper frame and lower frame) and fitting the compression plates into the outer openings of the respective molding frames to cover the molding frames, a predetermined molding space is formed in the molding frames, and the molding frame is formed. It is known that a desired mold (upper mold and lower mold) is obtained by compacting the molding sand filled in the space with the compression plate.

Then, in such a mold making machine, usually, with respect to any one of the compression plates fitted into the outer opening of the flask, a rod-shaped sprue bar extending to the pattern plate side is provided upright. In the state where the gate rod is brought into contact with the pattern plate, the molding operation as described above is performed, and then the gate rod is pulled out from the mold to communicate with the casting cavity formed in the mold. Are formed.

By the way, in such a sprue bar, while allowing the displacement of the compression platen toward the pattern plate side during compaction (squeeze) of the molding sand filled in the molding space, the pattern plate is surely Is required to be abutted against. Here, conventionally, in general, a plurality of stages of rod portions are fitted with a telescopic type telescopic structure, and a predetermined urging means such as a coil spring is provided to project the rod portions. , A sprue bar having a structure arranged inside has been used.

However, in the sprue bar having such a structure, the molding sand is likely to be caught in the gap between the sliding surfaces of the rod portions and easily bite in, and there is a risk that the molding sand may not be completely expanded due to the biting of the molding sand. Therefore, when a continuous molding operation is performed, the sprue bar does not come into contact with the pattern plate at the time of molding of the mold as described above, the runner of the obtained mold is not penetrated, and defective products are likely to occur. The problem was inherent.

Moreover, the sliding surface of the rod portion is easily worn by the inclusion of the molding sand into the gap between the sliding surfaces of the rod portion,
Therefore, there is a problem that the gap becomes large and biting of foundry sand is more likely to be caused, and it is difficult to obtain sufficient durability of the sprue bar.

Furthermore, in the conventional mold making machine, when the molding sand bites once between the protruding end surface of the sprue bar and the contact surface of the pattern plate during the continuous molding operation, it is attached to the pattern plate side. However, since it is difficult to remove the mold, there is a problem in that a mold to be subsequently molded will be defective.

(Problem to be solved) Here, the present invention has been made in view of the circumstances as described above, and the problem to be solved is that the casting sand between the sliding surfaces of the sprue bar having an expandable structure is used. It is an object of the present invention to provide a sprue bar in a molding machine which can effectively prevent both the entrapment of the sand and the encroachment of the foundry sand between the contact surfaces of the sprue bar and the pattern plate.

(Solution) In order to solve such a problem, according to the present invention, a pattern plate integrally formed with a model is sandwiched, and a pair of casting frames are superposed on both sides of the pattern plate, A compression molding plate is fitted in each of the outer openings of the frames to cover the molding frames to form a predetermined molding space in the molding frame, and the molding sand filled in the molding space is compacted by the compression plate. Thus, in a mold making machine that molds a predetermined mold, it is erected on the one compression platen and its tip is brought into contact with the pattern plate, thereby forming a gate in the mold, expansion and contraction. It is a sprue bar that can be expanded with a predetermined biasing force, and has a nesting pipe structure having an internal space, which is composed of a plurality of tubular bodies that are fitted so as to be able to extend and contract. While forming a jet hole on the protruding end surface of the tubular body located at the most distal end of these tubular bodies,
By providing the air supply means for supplying the compressed air to the internal space, the compressed air is caused to flow out from the internal space through the fitting surfaces of the respective tubular bodies and is also ejected through the ejection holes. The feature is that it is made possible.

(Examples) Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 schematically shows a concrete example of a mold making machine including a sprue bar having a structure according to the present invention. In this figure, reference numerals 10 and 12 denote an upper frame and a lower frame, respectively, as a casting frame, which are supported by a guide bar 14 so as to be movable in the approaching / separating directions. Further, the upper frame 10 and the lower frame 12 are supported by a support base 16 via a guide bar 14, and by the reversing cylinder 18, together with the support base 16, approximately 90 in the arrow direction in the drawing.
Each time, it can be rotated integrally. Then, as shown by the phantom lines in the figure, the upper frame 10 and the lower frame 12
At the pivotal position of the support base 16 where the and are to be superposed in the horizontal direction, the upper squeeze device 20 is provided on both sides in the superposing direction of the upper frame 10 and the lower frame 12, and each has a compression platen 19. The lower squeeze device 22 and the lower squeeze device 22 are respectively disposed, and the blow device 32 is disposed above the upper frame 10 and the lower frame 12, and on the other hand, the solid line in the figure As shown, the upper frame 10 and the lower frame 12 are positioned on both sides in the stacking direction of the upper frame 10 and the lower frame 12 at the pivotal position of the support base 16 where they are vertically stacked. The mold removing device 24 and the mold receiving device 26.
Are provided, respectively.

When molding a mold with a mold molding machine having such a structure, first, at the rotational position of the support base 16 as shown by the solid line in FIG. 1, as shown in FIG.
As shown in FIG. 5, between the facing surfaces of the upper frame 10 and the lower frame 12, a model 28 molded into a required casting shape is integrally formed in the central portion by a pattern transfer device (not shown). The pattern plate 30 formed by the above is guided and positioned, and the upper and lower frames 10 and 12 are sandwiched by the pattern plate 30.
And are overlaid.

Then, as shown in FIG. 2 (b), the support base 16
Is rotated to a rotation position as shown by an imaginary line in FIG. 1, and the upper squeeze device 20 and the lower squeeze device are respectively attached to the outer openings of the upper frame 10 and the lower frame 12. The compression plates 19, 19 of 22 are fitted and the openings are covered to form predetermined molding spaces 34, 34 inside the upper frame 10 and the lower frame 12, respectively. Further, there, a sprue bar 35 is erected on the compression platen 19 of the upper squeeze device 20, and the tip end surface thereof is brought into contact with the pattern plate 30 in the molding space 34.

Then, under such a state, through the inlet holes 36, 36 provided in the upper frame 10 and the lower frame 12, those molding spaces 34, 34 are formed.
For the inside, from the blow device 32, the casting sand 38 is fed and filled, and after the casting sand 38 is filled into the molding space 34, 34, both in the upper and lower squeeze devices 20, 22. The compression plates 19, 19 are displaced in a direction toward each other with a predetermined pressure, and the molding sand is compression-molded, whereby the upper mold 40 and the lower mold 42 as a mold, respectively,
It is molded (see FIG. 2 (c)).

Then, as shown in FIG. 2C, after the upper mold 40 and the lower mold 42 are molded, the upper and lower squeeze devices 20,
Compressors 19 and 19 in 22 will be released from the mold,
Also, at the same time when the compression plates 19 and 19 are released, the sprue bar 35
By also removing the die, a gate 43 having a shape corresponding to the gate rod 35 is formed inside the upper die 40.

Furthermore, after releasing the compression plates 19 and 19, the support base 16 is
When the upper frame 10 and the lower frame 12 are separated from each other by being rotated to a rotating position shown by a solid line in FIG. 1, as shown in FIG. 2 (d), The pattern plate 30 having the model 28 is die-cut from the upper die 40 and the lower die 42. Incidentally, in such die-cutting, as is well known, normally, the pattern plate 30 is ejected by a predetermined amount by an ejection mechanism (not shown) provided in the upper frame 10 and the lower frame 12, Die cutting from the upper mold 40 and the lower mold 42 of the pattern plate 30 is performed at the same time.

Then, after removing the pattern plate 30 and further tightening the core as required, the upper frame 10 and the lower frame 12 are overlapped again as shown in FIGS. 2 (e) and 2 (f). Together,
In the mold removing device 24, in a state where the upper mold 40 and the lower mold 42 are overlapped with each other, the upper frame 10 and the lower frame 12 are die-cut on the rod mold receiving device 26 to cast a predetermined shape. Cavity 44 and sprue 43 communicating with the casting cavity 44
However, the desired frameless molds, which are each formed inside, are obtained.

By the way, in the sprue bar 35 in the mold making machine having such a structure, the upper squeeze device is used at the time of molding.
In order to allow the displacement of the compression platen 19 on the pattern plate 30 side in 20, it is expandable and contractable, and is biased in the extension direction so as to surely make contact with the pattern plate 30. It is considered as a structure.

More specifically, as shown in FIG. 3, the sprue bar 35 includes a first tubular body 48, a second tubular body 50 and a third tubular body 52 which are nested in each other. It fits in the formula,
It has a three-stage telescopic expansion joint structure. That is, the first tubular body 48 is formed with an outer shape of a truncated cone shape having an inner hole 54 having a circular cross section that penetrates and extends in the axial direction, and the second tubular body 50 has an axial shape. The third cylindrical body 52 has an inner hole 58 that extends in the axial direction and is open to one end in the axial direction. It is formed to have a cylindrical shape at the bottom. Then, the second tubular body 50 is inside the inner hole 54 of the first tubular body 48, and the third tubular body 52 is inside the inner hole 56 of the second tubular body 50, respectively. By being fitted so as to be slidable in the axial direction, it has a nested tube structure that allows expansion and contraction of a predetermined stroke.

Incidentally, on the tip side of the first tubular body 48 and the second tubular body 50, annular locking portions 60, 62 which project inward in the radial direction to reduce the diameter of the inner holes 54, 56, While each is integrally formed, the second tubular body 50 and the third tubular body are formed.
On the base end side of 52, annular abutting portions 64 and 66, which protrude outward in the radial direction and increase the diameter of the outer peripheral surface, are integrally formed. Then, the contact portion 64 in the second tubular body 50, the contact portion 66 in the third tubular body 52 with respect to the locking portion 60 provided in the first tubular body 48. , The first cylinder of the second tubular body 50 and the third tubular body 52 by being brought into contact with the locking portion 62 provided in the second tubular body 50, respectively. Shape 48 and second cylinder 50
The inner holes 54 and 56 can be prevented from coming out of the inner holes.

Further, the outer peripheral surface on the tip end side of the second tubular body 50 is a tapered surface 70 having substantially the same inclination angle as the outer peripheral surface 68 of the first tubular body 48, and each tubular body 48, No step is formed at the fitting portion of 50 and 52.

Further, a substantially disc-shaped lid fitting 72 is attached to the opening portion on the base end side (large diameter side) of the first tubular body 48, and is fixed by a mounting bolt 74, thereby opening the opening. Is covered. As a result, one internal space 76 is formed inside the first to third tubular bodies 48, 50, 52.

In addition, a mounting screw is
While 78 is integrally formed to project, on the inner surface of the lid fitting 72, a rod-shaped projecting portion 80 that projects at a predetermined height into the internal space 76 is integrally formed. An air supply passage 82 is formed penetrating the inside of the mounting screw 78 and the protrusion 80 and opening into the internal space 76.

On the other hand, on the wall portion on the tip side (closed end side) of the third tubular body 52, a jet hole 84 of a predetermined size penetrating in the axial direction is bored, and through the jet hole 84, The interior space 76 communicates with the exterior space.

Furthermore, a coil spring 86 is provided in the internal space 76 formed inside the first to third cylindrical bodies 48, 50 and 52.
Is accommodated coaxially with those tubular bodies 48, 50, 52, and is capable of exerting a biasing force between the inner surface of the lid fitting 72 and the inner surface of the bottom wall of the third tubular body 52. It is arranged.
Then, based on the biasing force of this coil spring 86,
The second tubular body 50 and the third tubular body 52 are each biased in the protruding direction with respect to the first tubular body 48 so as to be extended.

Then, in the sprue rod 35 configured as described above, the mounting screw 78 provided on the lid fitting 72 is screwed to the compression platen 19 of the upper squeeze device 20 in the mold making machine. As a result, it is made to stand upright on the compression platen 19. Further, at the time of mounting on such a compression platen 19, an external air passage connected to an air pressure source (not shown) is connected to an air supply passage 82 formed in the lid fitting 72.

Thus, when the compression platen 19 is fitted from the opening side of the upper frame 10 at the time of molding the mold as shown in FIG. 2 (b), the projecting end surface of the sprue bar 35 has the pattern plate 30.
The molding space 34 is filled with the molding sand 38 under the abutting state, and the upper squeeze device 20 causes the compression platen 19 to move toward the pattern plate 30 side under a predetermined pressure. When the casting sand 38 is compacted, the casting sand 38 is compacted and molded.However, at the time of molding of such a mold, the sprue bar 35 is passed through the air supply passage 82 and inside the internal space 76. The compressed air will be supplied to. The compressed air may be supplied only when the compression platen 19 is fitted into the upper frame 10 or when the molding sand is filled, or may be constantly supplied.

That is, as a result, in the gate 35, compressed air does not reach the gap 88 between the fitting surfaces (sliding surfaces) of the first tubular body 48 and the second tubular body 50. The second tubular body 50 and the third tubular body 52 are each made to flow out through a gap 90 between the fitting surfaces (sliding surfaces) of the second tubular body 50 and the first tubular body.
It is ejected onto the projecting end face through the ejection holes 84 of 48. In addition, the outflow pressure and the ejection hole of the air that is caused to flow out through the fitting surfaces of the cylindrical bodies 48, 50, 52.
The jet pressure of the air jetted through 84 is the air supply passage.
The back pressure of the compressed air supplied through 82 can be adjusted by the hole diameter of the ejection hole 84 and the like.

Therefore, if the sprue bar 35 having such a structure is used, the intrusion or the entrapment of the foundry sand between the fitting surfaces of the tubular bodies 48, 50, 52 is discharged through the fitting surfaces. Since it can be very effectively prevented by the compressed air, the expandability of the sprue bar 35 can be advantageously ensured even in the continuous molding operation, and the sprue bar 35 can be brought into good contact with the pattern plate 30. Therefore, it is possible to very effectively prevent the occurrence of mold defects due to the non-penetration of the runner.

In addition, in the case of the sprue bar 35, the tubular bodies 48, 50,
The outflow of compressed air from between the fitting surfaces of 52 prevents the casting sand from entering the fitting surfaces, and when the tubular bodies 48, 50, 52 contract, the tubular bodies 48, 50 Since the foundry sand adhering to the outer peripheral surfaces of the cylindrical bodies 52, 52 can be advantageously removed, the wear of the cylindrical bodies 48, 50, 52 can be effectively reduced and excellent durability can be exhibited.

Furthermore, when such a sprue rod 35 is used, even when foundry sand adheres to the contact surface of the sprue rod 35 in the pattern plate 30, the sprue rod 35 is formed at the time of molding as described above.
The compressed air ejected through the ejection holes 84 provided on the projecting end surface of the can remove the adhering sand satisfactorily and quickly, and it is possible to effectively prevent the mold defect due to the adhering sand. It becomes.

As mentioned above, although one Example of this invention was described in detail, this is a literal illustration, and this invention is not interpreted limited to only such a specific example.

For example, in the sprue bar in the above-mentioned embodiment, it was formed with a telescopic expansion joint structure consisting of three tubular bodies 48, 50, 52, but it consists of two or more tubular bodies. It is also possible to form it with an expansion joint structure.

Further, in the above embodiment, the coil spring 86 was used as the biasing means for biasing the sprue bar in the extended state, but it is also possible to use various other biasing means, for example, the internal It is also possible to urge the sprue bar in an extended state by compressed air supplied into the space 76.

Furthermore, in the above embodiment, the sprue bar is attached to the compression platen 19 in the upper squeeze device 20, but the sprue bar is attached to the compression platen 19 in the lower squeeze device 22, It is also possible to form a runner in the lower mold 42.

Further, the mold making machine to which the present invention is applied should not be construed as being limited to the above description of the embodiments, and may be used as various mold making machines, especially mold making machines for making frameless molds. On the other hand, it goes without saying that any of them can be advantageously applied.

Although not listed one by one, the present invention can be carried out in variously modified, modified, improved, etc. modes based on the knowledge of those skilled in the art. Unless deviating from the spirit of the invention,
It goes without saying that it is included within the scope of the present invention.

(Effects of the Invention) As is apparent from the above description, in the sprue bar in the mold making machine constructed according to the present invention, the casting between the fitting surfaces of the tubular bodies fitted in the nest type is performed. Sand entry or biting can be effectively prevented by the compressed air flowing out between the mating surfaces, which prevents mold failure such as runner non-penetration due to the stretchability of the sprue bar. The generation can be advantageously prevented, the wear of the cylindrical bodies can be effectively reduced, and excellent durability can be exhibited.

Further, in such a sprue rod, the molding sand adhering to the contact surface of the sprue rod in the pattern plate can be satisfactorily and effectively compressed by the compressed air ejected through the ejection holes provided in the projecting end face of the sprue rod. Since it can be quickly removed, the mold failure due to such adhered sand can be effectively prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view schematically showing a concrete structure of a mold making machine to which the present invention is preferably applied. Further, FIGS. 2A to 2F are process explanatory views for explaining the mold making process in the mold making machine shown in FIG. Further, FIG. 3 is a vertical cross-sectional view showing a specific example of a sprue bar having a structure according to the present invention, which is used for the mold making machine shown in FIG. 10: Upper frame, 12: Lower frame 19: Compressor, 28: Model 30: Pattern plate, 34: Molding space 35: Gate rod, 38: Foundry sand 40: Upper mold, 42: Lower mold 43: Runner, 44 : Casting cavity 48: First tubular body, 50: Second tubular body 52: Third tubular body 54, 56, 58: Inner hole, 72: Lid metal fitting 76: Internal space, 82: Air supply Passage 84: Jet hole 86: Coil spring

Claims (1)

(57) [Scope of utility model registration request] 1. A pattern plate integrally formed with a model is sandwiched, a pair of casting frames are superposed on both sides of the pattern plate, and a compression plate is fitted into each of the outer openings of the respective casting frames to cover them. Thus, a predetermined molding space is formed in each of the flasks, and the molding sand filled in the molding space is compacted by the compression plate, whereby a mold molding machine that molds a predetermined mold is used. Is a sprue bar that is erected on the compression plate and has its tip abutted against the pattern plate to form a sprue in the mold, which is expandable and expandable with a predetermined biasing force. And has a nesting tube structure having an internal space, which is composed of a plurality of tubular bodies that are fitted so that they can expand and contract, and is positioned at the extreme end of these tubular bodies. By forming an ejection hole on the protruding end surface of the tubular body, the air supply means for supplying the compressed air to the internal space is provided so that the compressed air is fitted into each tubular body from the internal space. A sprue bar in a mold making machine, characterized in that the spout is made to flow out through a space between the facing surfaces and is made to spout out through the spouting hole.