JPH0688099B2 - Split mold - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a split mold, and more specifically, in a split mold in which a projection protruding from a split surface of an upper mold is retrofitted to a base of the upper mold. The present invention relates to an improved mounting structure for fixing a base to an upper mold base.

2. Description of the Related Art In the field of casting technology, a split mold in which an upper mold and a lower mold are combined with each other to define a cavity for casting is preferably used frequently. This split mold is one in which a recess is formed in each split surface (partition) of the upper mold and the lower mold, and a cavity is defined inside when the two molds are combined, and the split mold in the upper mold. While providing a convex portion projecting from the concave portion on the dividing surface of the lower mold, when the upper mold is placed on the lower mold,
It is roughly classified into a type in which a cavity for casting is defined between the convex portion and the concave portion. The latter is preferably used, for example, when casting a railroad crossing rail or the like with high-manganese steel.

Problems to be Solved by the Invention In order to mold the upper mold having the convex portion protruding from the mold dividing surface described above by sand-sanding between the wooden frame and the wooden mold, the dividing surface of the upper mold is It is inherently preferable to integrally mold the base to be the region and the projection protruding from the base. However, in many cases, the crossing rails and the like have different dimensions, and there is a strong tendency for productive casting. Therefore, with respect to the upper mold for casting a small lot of cast products, it is costly to manufacture the wooden mold required for integrally molding the base and the convex portion of the upper mold for each cast product having a different size. There are difficulties.

Therefore, a means has been implemented in which the base of the upper mold is first rough-molded, and a convex portion (generally referred to as a “shifting mold”) molded into a required shape is fixed to the divided surface of the upper mold later. For example, as disclosed in the prior art section of Japanese Patent Application Laid-Open No. 61-86047 filed by the applicant of the present application, a required convex island portion is formed by using a wooden frame and a wooden pattern on the dividing surface of the upper mold. There is known a method in which a wooden frame is removed after the molding sand has been hardened, and the convex island portion is clamped with an iron rod and an iron wire and attached to the upper die base portion. However, this method has a number of complicated steps and is costly, and has a drawback that it involves a dangerous work of suspending the upper mold at an angle. Therefore, as a solution to these problems, the furan mold molding method described in the above publication has been proposed, and it has been put to practical use.

For example, as shown in FIG. 8 to FIG. 10, a lower mold surrounded by a wooden frame 10 and having a wooden mold 12 embedded therein to form a required concave portion.
A wooden frame 18 for forming the upper mold 16 is placed on 14 and a die 20 having a wedge-shaped cross section is positioned on the dividing surface of the lower mold 14, and the molding sand is sand-filled with the furan resin. . After the molding sand has hardened, the upper mold 16 is inverted to remove the punching die 20 to form the sand removing portion 22, and then the dividing plane of the wooden frame 24 and the wooden die 16 and located on the sand removing portion 22. In this state, sand-filling is performed to form a convex portion 28 (“cutter mold”) having a required shape. According to this molding method, the molded convex portion 28 is fixed to the base portion 16a of the upper mold 16 through the sand removing portion 22 having an inverse taper as shown in the drawing, which is troublesome. There is an advantage that the number of steps can be reduced and an upper mold having a shift mold can be safely manufactured.

However, in this molding method, after the upper mold is cured, the die 20
However, since this die 20 is firmly adhered to the foundry sand with furan resin,
Even if it is configured so that it can be divided by a plurality of wood pieces, it is actually difficult to remove it, and a new defect such as damage to the sand removing part 22 is often pointed out.

OBJECT OF THE INVENTION The present invention has been proposed in order to satisfactorily solve this problem in view of the above-mentioned drawbacks inherent in the split mold provided with the above-described related art mold, and it is necessary to use a die. It is an object of the present invention to provide a means for safely and surely attaching a convex portion to an upper die, which eliminates the need for a die removing operation which was difficult in the past.

Means for Solving the Problems In order to overcome the above-mentioned problems and achieve an intended purpose, the present invention is to mount an upper die on a lower die to thereby form a convex portion protruding from a dividing surface of the upper die. Facing the recess formed in the lower mold,
In a split mold in which a cavity for casting is defined between a convex portion and a concave portion, the split mold is provided separately from the upper mold, and when the mold is attached to the upper mold, from the split surface to the concave portion of the lower mold. A channel member having a longitudinal opening that is embedded in the upper mold base and opens to the outside of the base, and an engaging portion formed along the longitudinal opening of the channel member. The projection is attached to the upper mold by partially exposing the bottom of the side facing the upper mold dividing surface to the long opening of the channel member, and the engagement of the long opening. It is characterized in that the protrusion is prevented from coming off by being engaged at the portion.

EXAMPLES Next, a split mold according to the present invention will be described below with reference to the accompanying drawings with reference to preferred examples. The same members as those described with reference to FIGS. 8 to 10 are designated by the same reference numerals. 1 to 5 are views for explaining a process of manufacturing a split mold according to an embodiment of the present invention with respect to a mold for casting a crossing rail over time. In this method, a so-called channel member having an engaging portion is used as a means for fixing the convex portion 28 to the upper die base portion 16a. That is, inside the wooden frame 10 for forming the lower mold 14, a wooden mold 12 having an uneven outer contour that defines the upper surface of the crossing rail to be cast is arranged, and the wooden mold 10 and the wooden mold 12 are arranged. Pour molding sand and furan resin between them and cure.

As shown in FIG. _1, on the split surface S ₁ of the lower mold 14, a channel member 30 made of, for example, a lip groove type steel having a cross section which is a lightweight steel for building materials has a longitudinal opening M.
A plurality of them are placed in parallel on the wooden mold 12 so as to face downward on the lower mold dividing surface S ₁ side. Then, as shown in FIG. 2, a wooden frame 18 for molding the upper mold 16 is attached to the lower mold 14
The base 16a of the upper mold 16 is molded by placing it on the wooden frame 10 and sand-filling the molding sand and the furan resin therein.
At this time, the channel member 30 is, as described above, the lower die dividing surface.
Since the opening M is mounted on S ₁ so as to face downward, a space extending along the channel member 30 is defined inside the channel member 30. The opening M of the channel member 30
The both edge portions extending in the longitudinal direction are respectively bent inward as shown in FIG. 1 to form key-shaped engaging portions 30a, 30a facing each other.

Next, as shown in FIG. 3, when the upper mold 16 is lifted from the lower mold 14 and inverted, the dividing surface S ₂ of the upper mold 16 is directed upward, and thus the opening M of the channel member 30 is also moved upward. Is oriented. Further, by removing the wooden mold 12 from the lower mold 14, a required concave portion 32 that is recessed in the dividing surface S ₁ is formed.

As shown in FIG. 4, in the divided surface S ₂ of the inverted upper mold 16,
At the position surrounding the position where the channel member 30 is arranged, the wooden frame 24
And, a wooden mold 26 having an undulating contour defining the lower surface of the crossing rail is arranged, and the molding sand and the furan resin are sand-filled in the obtained space. Crate 24 and pattern 26 after sand hardens
By removing and, the convex surface on the dividing surface S ₂ of the upper mold 16 is
28 is molded. At this time, the foundry sand is removed from the channel member 30.
Since the openings M of the upper mold 16 tightly extend to the openings M of the upper mold 16, the convex portion 28 is securely fixed to the base 16a of the upper mold 16 in the presence of the engaging portion 30a of the channel mold 30 after the molding sand is hardened. . In this state, the upper die 16 is inverted again and placed on the dividing surface S ₁ of the lower die 14 as shown in FIG.
Facing the recess 32 of the lower mold 14, a cavity C for casting the crossing rail is formed.

If the channel member 30 has an engaging portion, a round bar steel 34 is welded along the end edge of the channel member 30 having a letter-shaped cross section as shown in FIG. 6 in addition to the lip groove type steel. Or as shown in FIG. A reverse taper may be added so that Further, it is more preferable if the channel member 30 is provided with through holes 30b for degassing at required intervals.

As described above, in the split mold according to the present invention, the channel member is embedded in the base of the upper mold to direct the longitudinal opening toward the outside of the base, and the bottom of the convex portion is placed in the opening of the channel member. The protrusion is attached to the upper mold by facing it, and at the same time, the engaging portion provided along the opening prevents the detachment of the convex portion engaged and held. For this reason, the complicated work of fixing the convex portion and the difficult work of detaching the die from the upper mold, which are conventionally required, are unnecessary, and the convex portion can be surely attached to the upper mold by the channel member. Therefore, especially when casting a small lot is required,
There is an advantage that the split mold according to the present invention can be manufactured at low cost and can be effectively utilized.

[Brief description of drawings]

1 to 5 are longitudinal sectional views for explaining a time-dependent process of manufacturing a split mold according to an embodiment of the present invention with respect to a mold for casting a crossing rail, FIG. 6 and FIG. FIG. 8 is a perspective view showing another configuration example of the channel member used in the embodiment of the present invention, and FIGS. 8 to 10 are longitudinal cross-sectional views showing steps of manufacturing a split mold according to the prior art over time. 14 …… Lower mold, 16 …… Upper mold 16a …… Base part, 28 …… Convex part (clamping type) 30 …… Channel member, 30a …… Engaging part 32 …… Concave part, C …… Cavity part, M… … Aperture, S ₂ …… Upper parting surface

Claims (1)

[Claims] 1. The upper mold (16) is placed on the lower mold (14) so that the convex portion (28) protruding from the dividing surface (S ₂ ) of the upper mold (16) has a lower mold (14). Facing the recess (32) formed in
In a split mold in which a cavity (C) for casting is defined between a convex portion (28) and a concave portion (32), the split mold is provided separately from the upper mold (16), and the upper mold (16) is provided. ) From the dividing surface (S ₂ ) to the recess (3) of the lower mold (14).
2) A channel member (30) having a convex part (28) which can be exposed in the inside and a longitudinal opening (M) which is embedded in the base part (16a) of the upper mold (16) and opens to the outside of the base part. And an engaging portion (30a, 30a) formed along the longitudinal opening (M) of the channel member (30), the convex portion (28) being formed on the upper mold dividing surface (S ₂ ). The bottom portion on the pointing side is provided with the longitudinal opening (M) of the channel member (30).
Is attached to the upper mold (16) by partially facing the upper mold (16) and is engaged with the engaging portions (30a, 30a) of the longitudinal opening (M) to prevent the convex portion (28) from falling off. A split mold characterized in that