JPS5841172B2 - Goseijiyushiseiyoukanagata - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold for molding synthetic resin, and is used to mold a molded product with an upright handle having a lateral protrusion or other undercut inside a container-shaped molded product such as a transportation box. The present invention relates to a synthetic resin mold that allows the molded product to be removed from the mold.

Conventionally, synthetic resin molds for molding molded products with undercuts, such as upright handles with lateral protrusions, have been equipped with a pair of wedge-shaped slide cores as part of the male core of the movable mold. There is one in which a recess for undercut molding is provided on opposing surfaces of the slide core, and the undercut portion is removed by moving the slide core laterally when the mold is split.

However, in the conventional synthetic resin molding mold described above, the wedge-shaped slide core portion of the male core and the block that sandwiches the wedge-shaped slide core are connected by providing a dovetail groove or the like, and the movement of the block in the mold opening direction is prevented. However, since the wedge-shaped slide core is made to move laterally, the sliding parts connected by dovetail grooves etc. during actual molding do not slide smoothly, making it difficult for the undercut to bend or not coming off at all. There are even cases.

Furthermore, as molding is repeated, the sliding parts become loose due to abrasion, and the split molds do not fit in the predetermined positions, resulting in irregularities in the dimensions of the molded product.

This invention eliminates the drawbacks of the conventional molds for molding synthetic resins as described above, and enables molded products with undercuts such as upright handles that have lateral protrusions inside the molded product to be easily released. The purpose of the present invention is to provide a mold for molding synthetic resin that is moisturized.

The gist of this invention is to have a concave portion for forming an undercut portion such as a handle formed as a bridge in the opening of the molded product between opposing surfaces, and to have a concave portion for forming an undercut portion such as a handle, which is mutually connected at the tapered end portion located on the base side of the male core. A pair of wedge-shaped core blocks 1, 1 that can be opened and closed in a hinge-like manner, and a core block 2 that surrounds the wedge-shaped core blocks 1, 1 and is movable separately from the wedge-shaped core blocks 1, 1. . Protrusions 5, 5 that can slide on the sides of the fitting parts 8, 8 are provided, and the fitting parts 8, 5 of the wedge-shaped core blocks 1, 1 are provided.
The side surface that abuts the protrusion 5°5 at 8 is the protrusion 5,
The protrusions 5, 5 are inclined or curved toward the 5 side, and as the core blocks 2, 2 move when the molded product is released, the protrusions 5, 5
is slid while being pressed against the fitting portions 8, 8, so that the wedge-shaped core blocks 1, 1 are opened and the undercut portion of the molded product is separated from the synthetic resin molding die. There is a synthetic resin molding mold characterized in that the male core is configured to I can do it.

In other words, by opening and closing the wedge-shaped core block in a hinge-like manner, there is no sliding part in guide grooves such as dovetail grooves as in the conventional type, so the movement of the mold is extremely smooth, and the movement of the mold is done extremely smoothly. Problems can also be resolved.

A more detailed explanation will be given below using the drawings.

FIG. 1 is a partially cutaway assembled cross-sectional view when the mold is clamped, and FIG. 2 is a partially cutaway cross-sectional view showing the part (■) when the mold is opened.

A pair of left and right wedge-shaped core blocks 1.sub.1 are connected by a fitting pin 3, and a core block 2.sub.2 is provided between these wedge-shaped core blocks 1,1.

Now, as the core flocs 2, 2 move from the state shown in Fig. 1 (the state at the time of mold clamping) to the state shown in Fig. 2 (the state moved in the release direction of the molded product), (rust-shaped core blocks 1, 1
is a wedge-shaped core block 1, 1 with the fitting pin 3 as the axis.
It is pushed open by a spring 4 provided between the two.

At this time, the wedge-shaped core blocks 1, 1 are connected to a hydraulic cylinder or a compression spring fixed to the core block 2゜2 or the back plate of the mold via the support body 9 and the support rod 10, and the core When the blocks 2, 2 are moved, they are separated from the core block 2.2. In order to ensure this opening movement, the mechanism shown in FIG. 3 is provided.

That is, the core block 2.2 has projections of suitable shape and structure, for example pins 5, 5 accommodated in apertures 6, 6;
Compression springs 7, 7 are provided between the pins 5, 5 and the bottoms of the openings 6, 6, and as the core blocks 2, 2 move in the mold opening direction, the pins 5, 5 compress the wedge-shaped core blocks 1, 1. It moves while pressing down the upper fitting parts 8, 8 (see Fig. 4), and works to push open the wedge-shaped core block 1.1.

Here, the fitting portion 8 of the wedge-shaped core blocks 1, 1,
The surface in contact with pin 5゜5 of 8 is wedge-shaped core block 1,
The pins 5, 5 are inclined or curved toward the side to which they are pressed with respect to the center line of the fitting.

Figures 3 and 4 show the fitting portion 8 of the wedge-shaped core blocks 1, 1,
This is an example showing 8.

With this configuration, the core blocks 2, 2 move in the mold opening direction, and the pins 5, 5 are slid on the fitting parts 8, 8 of the wedge-shaped core blocks 1, 1, so that the wedge-shaped core When pushing and expanding the blocks 1, 1, the gap between the fitting parts 8, 8 and the core blocks 2, 2 at the position of the pins 5.5 is set within a range where the compression springs 1, 7 can sufficiently operate. 5, 5 is ensured, and the release spring 4 also functions smoothly.

(If the fitting parts 8, 8 of the wedge-shaped core blocks 1, 1 are not tilted, the pushing stroke of the pins 5, 5 must be made large to push the fitting parts 8, 8, and the stability and reliability It becomes a sexual problem.

Further, when the wedge-shaped core blocks 1, 1 are opened, the end corner portions 11 of the core blocks 2, 2 move while contacting the wall surfaces of the wedge-shaped core blocks 1, 1 (see FIG. 6).

Therefore, there is no problem with the smooth opening of the mold, but as the mold is repeatedly opened and closed, wear will occur on the corner part 11, and the mold formed due to this wear during molding. Resin may flow into the gap and cause cracks, resulting in defective molded products.

To solve this problem, as shown in FIGS. 7 and 8, a trapezoidal recess is provided at the end corner of the core blocks 2, 2, and the wedge-shaped core block 1 is fitted into the recess. , 1 is preferably provided with a flange-like protrusion at the end thereof.

By providing a step at the end of the surface where the core blocks 2, 2 and the wedge-shaped core flocks 1, 1 come into contact with each other in this way, the wedge-shaped core block 1 can be moved by the movement of the core blocks 2, 2.
, 1 will be made mostly at the corner portion 13.

Therefore, even if there is abrasion at the contact portion, there will be no occurrence of flakes or the like in the molded product, and a good molded product can be obtained.

Next, an example of the order of splitting the mold will be described using an example.

9, 10, and 11 are partially cutaway sectional views of the mold showing the mold opening process.

9 to 11, 15 is a hydraulic cylinder, 16 is a mold back plate, 17 is a cavity block, 18
is a slide core.

FIG. 9 shows the state of the mold upon completion of molding and cooling.

FIG. 10 shows the state when the mold starts to be opened. The hydraulic cylinder 15 is actuated to push the wedge-shaped core flocks 1, 1 while the core block 2.2 is moved in the mold opening direction. At the same time, the slide core 18 The undercut on the side is also moved laterally and the undercut on the side is removed.

At this time, the pins 5, 5 provided with the core blocks 2, 2 move while pressing down the fitting portions 8, 8 of the wedge-shaped core blocks 1, 1, so that the wedge-shaped core blocks 1, 1 are opened.

FIG. 11 shows a state in which the core blocks 2, 2 are moved and the wedge-shaped core blocks 1, 1 are pushed open so that the internal undercut, that is, the handle portion 19, can be released. 1.1 is core block 2,2
At the same time, the mold is moved in the mold opening direction, and the mold is opened to a position where the molded product 20 can be released from the mold.

In this way, it is possible to integrally mold a container with an internal handle-like undercut, making it possible to mold transport containers that are convenient in use and of various designs.

Furthermore, it is possible to easily obtain a box-shaped container with long side surfaces without bending, which is a problem with box-shaped containers having long sides.

Furthermore, since there are no parts that slide in guide grooves such as dovetail grooves, the mold moves extremely smoothly, undercuts can be easily removed, and the sliding parts do not wear out, so there is no problem with the dimensions of the molded product. It has the effect of not being there.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the wedge-shaped core block in the mold clamped state, Figure 2 is a cross-sectional view of the wedge-shaped core block when the mold is open, Figure 3 is a cross-sectional view showing the main parts of the wedge-shaped core block, and Figure 4 is the same slope. Figures 5 to 8 are cross-sectional views showing the movement of the tip of the wedge-shaped core block, and Figures 9 to 11 are cross-sectional views showing the process of splitting the mold. 1... Wedge-shaped core block, 2...
Core block, 3...Mating pin, 4...
・Spring, 5... Pin, 6... Opening, 7... Compression spring, 8... Fitting part,
9...Support body, 10...Support rod, 11
゜12.13,14... some corners, 15...
... Hydraulic cylinder, 16 ... Mold back plate, 17 ... Cavity flock, 18.
... Slide core, 19 ... Undercut part, 20 ... Molded product.

Claims (1)

[Claims] 1 A concave part for forming an undercut part such as a handle is formed by bridging the opening of the molded product between the opposing surfaces, and the parts are hingedly fitted to each other at the tapered ends located on the base side of the male core. A pair of combined wedge-shaped core blocks 1, 1 that can be opened and closed
and a core block 2 which surrounds the wedge-shaped core blocks 1 and 1 and is movable separately from the wedge-shaped core blocks 1.
, 2, in the synthetic resin molding die, the force of the required portion of the male core is reduced. hand,
A protrusion 5°5 that can slide on the side surface of the fitting portions 8, 8 is provided, and the side surface of the wedge-shaped core block 1, 1 that abuts the protrusion 5, 5 on the fitting portion 8, 8 is The protrusions 5, 5 are inclined or curved toward the side, and when the molded product is released, the protrusions 5, 5 remain pressed against the fitting parts 8, 8 as the core block 2.2 moves. The male core is configured such that when slid, the wedge-shaped core flocks 1, 1 are opened and the undercut portion of the molded product is separated from the synthetic resin mold. A mold for synthetic resin molding featuring the following.