JPS6362367B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a molded article having an embedded handle.

The recent development of molding technology for plastics and resin concrete has been remarkable, and most of the traditional wooden and metal products have come to be replaced by molded products made of plastic and resin concrete. Increasingly, such molded products are being used instead.

By the way, things like manhole covers need to have handles so that they can be opened and closed easily.
In the conventional molding technology, there is no suitable method for simultaneously providing a recessed type handle as shown in FIG. It had not been developed.
For this reason, in conventional molded products, the sixth
It has been common practice to provide a handle as shown in the figure, that is, a simple handle in which a gripping portion 22 is protruded from one side wall of a handle recess 21. However, such handles
Compared to the embedded type handle shown in FIG. 5, it has disadvantages such as the hand slips easily, making it impossible to use a hand key, and the grip part 22 being weak in strength, it is easily damaged.

The present invention has been made in view of the above-mentioned circumstances in order to provide a new and useful manufacturing method by which a molded product with an embedded handle can be easily manufactured.

Hereinafter, the manufacturing method of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic explanatory diagram illustrating the production of a molded product such as a manhole cover with an embedded handle using a thermosetting material such as resin concrete based on the manufacturing method of the present invention, and FIG. 3 is a perspective view showing an example of a molding die and a split core used in the present invention, and FIG. 3 is a sectional view taken along the line -- in FIG. 2.

That is, the manufacturing method of the present invention begins by temporarily fixing the split mold core 3 holding the handle member 2 to the molding die 1, as shown in FIGS. 1A and 1B. The molding die 1 used in the present invention is as shown in FIG.
A convex portion 11 having a core fitting groove 111 is formed at a location on the inner surface of the mold 1 where a handle is to be provided.In this embodiment, in order to minimize the increase in mold cost, As shown in Fig. 3, the core fitting groove 11
1 with an inverted U-shaped cross section,
The insert 11' is fitted into the inner recess of the mold 1 with the fasteners 12 and 1.
The convex portion 11 is formed by fastening and fixing at 2. However, due to cutting etc., the convex portion 11
Of course, it is also possible to form it integrally with the molding die 1.

In addition, as shown in FIG. 2, the split core 3 has grooves 32, 32 for holding the handle member 2 formed on the mating surfaces of both core halves 31, 31, so that the split core 3 has grooves 32, 32 for holding the handle member 2. A portion of the long handle member 2 excluding both ends is inserted into the holding groove 3.
2 and 32 to hold it from both sides and fit it into the fitting groove 111 of the inner surface convex part 11 of the mold 1.

The insert 11' constituting the inner surface convex portion 11 of the mold 1 and the split mold core 3 are both made of iron or other magnetic metal, and The inner wall portion 112 of the groove 111 is subjected to magnetization treatment. Therefore, the split core 3 is inserted into the groove 1 of the insert 11'.
When inserted into the core 11, the core 3 is temporarily fixed in a detachable manner by magnetic adhesion. In this case, the tip end surface (upper end surface) of the core 3 that comes into contact with the back wall portion 112
The core 3 may be subjected to magnetization treatment, or may be constructed so that the core 3 can be detachably temporarily fixed by an appropriate means other than magnetic attachment. Further, the split core 3 is not limited to a two-piece type, and can be designed to be divided into three or four pieces as appropriate for easy division and removal.

The configuration of other parts of the mold 1 used in the present invention is the same as that of a normal press molding or casting mold, and around the mold 1 there are heaters 4 and cold water passages 5. has been deployed.

As shown in FIGS. 1A and 1B, the split core 3 holding the handle member 2 is inserted into the core insertion groove 111 of the convex part 11 on the inner surface of the mold 1 and temporarily fixed, and the A molding material a (thermosetting material in this embodiment) required for a certain molded product is filled into a mold 1, press-molded as shown in FIG. 1C, and hardened by heating with heaters 4. In this case, both ends of the handle member 2 protruding from the split core 2 are embedded in the filling material a.
It should be noted that, as long as the molding material a has improved fluidity, not only the above-mentioned press molding but also injection molding or the like can be used. When the molding material a is a thermoplastic material such as plastic, it goes without saying that it is hardened by cooling the mold 1 by passing water through the cold water passage.

After the molding material a is filled and hardened in this manner, the mold 1 is opened as shown in FIG. 1D, and the molded product A is released. In this case, both ends of the handle member 2 are connected to the mold 1.
Handle concave portion 21 formed by convex portion 11 on the inner surface
Since the split mold core 3 holding the handle member 2 is embedded in the side wall of the molded product A, the split mold core 3 that holds the handle member 2 is separated from the mold 1 and remains in the handle recess 21 of the molded product A.

Finally, as shown in FIG. 1E, the split core 3 is divided into core halves 31, 31 and removed from the molded product A to obtain a molded product A having an embedded handle. In addition,
If the handle member 2 has a rhombic shape as in the embodiment, the core 3 can be easily separated and removed.

FIG. 4 is a plan view of a round lid for a drainage basin made of resin concrete manufactured by the manufacturing method of the present invention as described above, and FIG. 5 is a cross-sectional view taken along the line -- in FIG. In A', two embedded handles are provided at symmetrical positions in which both ends of the handle member 2 are embedded in the side wall of the handle recess 21 having a rectangular planar shape. 2, a rectangular bar material whose both ends are horizontally long and flat is used. The reason that both ends of the handle member 2 are flat is that the handle member 2 can be easily pulled up by hand or with a hand key.
In addition to preventing rotation and slipping,
Thickness t from the surface of round lid A' to both ends
This is to increase the strength as much as possible. As the handle member 2, in addition to round rods, straight rods with elliptical, triangular, square, or polygonal cross sections, and even bent rods made by convexly bending these rods at the center can of course be used. In that case, a split core 3 having a holding groove 32 of a shape corresponding to the rod used may be used. In addition, the convex portion 1 on the inner surface of the mold 1
It is of course possible to change the shape of the handle recess 21 to best match the design of the surface of the round lid A' by variously changing the shape of the core 11' constituting the handle A'.

As described above, the present invention allows the split mold core 3, which holds the handle member 2 except for both ends, from both sides to be inserted into the insertion groove 111 of the convex portion 11 on the inner surface of the mold 1, and can be removed. After filling the molding material a into the mold 1 and hardening it, the mold 1 is filled with the split mold core 3.
By releasing the split mold core 3 from the mold and then dividing it and removing it from the molded product A, it is possible to manufacture a molded product with an embedded handle, which has been difficult in the past. In particular, when the convex portion 11 on the inner surface of the mold 1 is formed by the insert 11' as in the embodiment,
Since it is only necessary to use a conventional mold and fix the insert 11' thereto, there is no need to create a new mold 1, which is economically advantageous. By changing the ', handle recesses 21 of various shapes that match well with the molded product in terms of design can be created.
It has the advantage of being able to form In addition, if magnetic attachment means is adopted as the means for temporarily fixing the split core 3 as in the embodiment, the core 3 can be easily and reliably temporarily fixed by simply fitting it into the fitting groove 111. There is an advantage that the split mold core 3 can be easily removed during demolding. In addition, when using a handle member 2 with both ends flattened as in the embodiment, rotation of the handle member 2 can be prevented as described above, so it will not slip when pulled up, and the wall thickness t It also has the advantage of increasing strength.

In addition, as an alternative method to obtain a molded product with an embedded handle, a water-soluble core is temporarily fixed to the inner surface of a normal mold.
It is not inconceivable to immerse the molded product that has been released from the mold with the core left in water to dissolve the core, but with this method, temporary fixing of the core is troublesome and difficult. Since it takes time for the core to melt down, manufacturing efficiency decreases, and a separate large water tank is required to soak the molded product, and as the core melts down, new cores must be used one after another. Therefore, it is economically disadvantageous, and it is clear that the same effect as the present invention cannot be expected.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram of an embodiment of the manufacturing method of the present invention, Fig. 2 is a perspective view showing an example of a molding die and a split core used in the present invention, and Fig. 3 is a -
4 is a plan view of a round lid for a drainage basin manufactured by the manufacturing method of the present invention, FIG. 5 is a sectional view taken along the - line in FIG. 4, and FIG. 6 is a handle of a conventional molded product. FIG. (Explanation of main symbols in the drawings), 1...Molding mold,
11... Convex portion, 11'... Insert, 111... Core fitting groove, 2... Handle member, 3... Split core, a...
...Molding material, A...Molded product.

Claims (1)

[Claims] 1 Core fitting groove 111 of a molding die 1 having a convex portion 11 provided with a core fitting groove 111 on the inner surface
Then, a split core 3 that held the handle member 2 except for its ends from both sides was fitted and temporarily secured in a removable manner, and the molding material a was filled into the molding die 1 and hardened. After that, the molding die 1 is released leaving the split mold core 3, and then the split mold core 3 is divided to form a molded product A.
A method for manufacturing a molded product having a recessed handle, which is characterized in that the handle is removed.