JPH011504A - Mold manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a mold body of a press molding or injection molding mold from concrete.

[Conventional technology]

Conventionally, when concrete is used for press molding molds, etc., in order to improve the structural strength, for example, concrete is used.
The one shown in the figure is used. In this case, the upper and lower press molds 1a and lb are made of cast iron or other metal formwork 2a.
, 2b, and mold bodies 3a, 3b made of concrete, and the strength of the press molds 1a, 1b is borne by the external metal formworks 2a, 2b (see Japanese Patent Laid-Open No. 115670/1983).

[Problem that the invention seeks to solve]

However, such conventional concrete molds use metal formwork, which complicates the manufacturing process, and also causes local bending and tensile forces in the concrete part of the mold. In this case, the strength of the mold for forming concrete is low because the force to counter the force is weak.

On the other hand, as a method of reinforcing concrete materials, there is a method of applying tension to piano wire in advance, such as concrete sleepers for railways, and then pouring concrete slurry into it and solidifying it, giving compressive force to the concrete material in advance. .

However, in order to apply this kind of compressive force to a large object such as a concrete mold, it is necessary to use a thick bolt-like material rather than a thin material such as piano wire, so the bolt must be pre-installed. There was a problem in that it was necessary to install large-scale mechanical equipment in order to apply tensile force.

The present invention has been made in view of these conventional problems, and an object of the present invention is to manufacture a high-strength concrete mold using simple equipment.

(Means for Solving the Problems) In order to achieve this object, the present invention manufactures a mold using a mold body made by pouring concrete slurry and hardening it. In this case, a through hole is formed through the mold body in the above-mentioned curing process, and a step of inserting a bolt into the through hole and heating the bolt is provided during the formation process of the through hole or after curing, and the bolt is heated to a predetermined temperature. I decided to hook the nut onto the heated bolt.

[Effect]

Next, the present invention will be described in detail. In the concrete mold body, the through holes through which the bolts are inserted are formed during the hardening process of the concrete slurry, so that the through holes can be easily formed. A bolt is inserted into the through hole, and the bolt is heated to a temperature higher than room temperature due to the heating process, and is hung with a nut before being allowed to cool, so that the bolt contracts when it is allowed to cool and returns to room temperature. to generate tension on the bolt. Therefore, compressive force is always applied to the concrete mold body, and the concrete mold body can be made strong against bending and tensile forces.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a sectional view showing the manufacturing process of a concrete forming mold according to an embodiment of the present invention. The concrete mold is
As shown in FIG. 1(a), the model 5 has a formwork 6 and an upper frame 7.
A mold body is formed by attaching the concrete slurry 8 and pouring concrete slurry 8, and a through hole 12 passing through the mold body is formed during the hardening process of the concrete. To form the through hole 12, a core metal 9 with a mold release agent applied to its surface is placed through the formwork 6 where concrete slurry is poured, and after the concrete slurry is poured and solidified, the core bar 9 is inserted into the formwork 6. The gold 9 is removed, and the frame 6 and upper frame 7 are removed to form a mold body 11 having a through hole 12.

Then, as shown in FIG. 1(b), bolts 13 that have been heated in advance to a temperature higher than room temperature are inserted into the through holes 12 of the mold body 11, and the bolts 13 are inserted into both sides of the mold body 11. The reinforcing steel plate 15 passed through is brought into contact with the reinforcing steel plate 15. Then, before the bolt 13 from the outside of the reinforcing steel plate 15 is allowed to cool, a nut 16 is attached and loosely tightened. The bolts 13 are then left to cool and contract as they cool, so tension is applied to the bolts and compressive force is applied to the mold body 11.

The lower mold 10 of the mold is formed in the same manner using the mold body 11 as a model, and tension is applied by inserting bolts in the same manner as described above.

In this case, it is desirable that the tension generated by each bolt be a predetermined constant force, but by heating the bolt to a predetermined constant temperature, the tension generated by the bolt can be fixed. It becomes a constant and a force,
The required compressive force can be applied to the concrete mold. Therefore, in the manufacturing method of the present invention, compared to the manufacturing method of inserting a bolt into the insertion hole 12 and tightening it with a nut, the method of tightening the bolt causes the bolt to tighten due to variations in the frictional force when the nut rotates. This has a great advantage compared to the case where it is difficult to keep the tension constant.

The through holes 12 and bolts 13 for applying tension to the mold body 11 are arranged not only in a vertical relationship as shown in FIG. be.

Furthermore, as in the other embodiment shown in FIG. 2, through holes 17, bolts 18, and reinforcing steel plates 19 are provided not only on the pair of opposing sides of the mold, but also on the other opposing sides, so that the nut 20 can be tightened. It is then tightened by the contraction of the bolt 18. In this way, the bolts 13, 18 may be disposed in a cross shape, intersecting each other so as not to conflict with each other, so as to apply compressive force to the mold 11 from all sides. By applying compressive force from the other direction using a large number of bolts in this manner, the strength of the concrete mold can be improved even when bending force acts two-dimensionally.

As another example of the step of heating the bolt, after the bolt is inserted into the through hole 12, an electric current is applied to the bolt to heat it, and the nut 16 is attached and tightened loosely, so that the bolt 13 is heated.
Compressive force can be applied to the concrete mold 1 by allowing it to cool. By adjusting the current strength and energization time appropriately, the heating temperature of the bolt can be kept at a predetermined value, and the tightening force after cooling can be kept constant.

In addition, in order to form the through hole, as shown in FIG.
It is also possible to form the through hole 26 on the inner surface of the pipe 25 by pouring and solidifying concrete slurry. Moreover, instead of using the core bar 9 in the embodiment shown in FIG. 1, if a mold release material is directly applied to the surface of the bolt 13 and embedded in a concrete mold, a through hole can be formed on the outer surface of the mold release material. Since the bolt 13 is formed, a current may be passed through the bolt 13 to heat it.

(Effects of the Invention) Since the present invention has the above-described structure and operation, it is possible to apply compressive force to the concrete mold in advance and make it strong against bending and tensile force without requiring any costly mechanical equipment. This makes it possible to improve the strength of the mold, and by setting the heating temperature of the bolt to a fixed value, it is possible to apply accurate and uniform compressive force, resulting in high strength and easy production. A mold having a concrete mold body can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a mold to which an embodiment of the present invention is being applied;
Fig. 2 is a perspective view of the main parts of a mold to which another embodiment of the present invention is applied, Fig. 3 is a sectional view of the main parts of a mold to which still another embodiment is applied, and Fig. 4 is a conventional concrete mold. FIG. 3 is a cross-sectional view of the mold. 8...Concrete slurry 11...Mold body 12...Through hole 13...Bolt 16...Natsuto patent applicant Nissan Motor Co., Ltd.

Claims (1)

[Claims] When manufacturing a mold using a mold body made by pouring concrete slurry and curing it, a through hole is formed through the mold body, and during the process of forming the through hole or after hardening,
1. A method of manufacturing a mold, comprising the step of inserting a bolt into the through hole and heating the bolt to a predetermined temperature, and then hooking a nut to the bolt heated to the predetermined temperature.