JPH03159712A - Mold apparatus for resin - Google Patents

Abstract

PURPOSE:To shorten molding cycles without utilizing a cylinder for sliding an insert by urging a slide block forming an under cut part in the mold opening direction and constituting it slidably in the direction of coming out of the under cut part during the mold opening period. CONSTITUTION:In a mold for a molding 1 having a rid 1a to be an under cut on the cavity side, a rod 2 is disposed slantly with respect to the mold opening direction and fixed to a cavity 8 in its upper end and further a spring 3 is placed in the outer periphery thereof. A slide block 4 has a formation part 4b forming the butt surface of the spring 3 and the under cut part of the rid 1a and the sliding part 4c is held by the holding part 5a of a slide guide plate 5 fixed on the cavity 8 and in consequence guide slidably. And, on the lower and part of the holding part 5a, a stopper 6 that serves to slide and then stop the slide block 4 is fixed and a slide core 7 which acts to slidingly restore the slide block 4 in opposition to the urging force of the spring 3 during the mold clamping period is moved reciprocally laterally accompanying the opening and closing operations of the mold by a rod 8a extending from the cavity 8 to the slantly downward direction.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a mold device for removing an undercut from a hollow part having a rib serving as an undercut on the cavity side.

BACKGROUND OF THE INVENTION A conventional mold apparatus of this type has a structure shown in FIGS. 4 and 5.

In FIG. 5, numeral 9 is a box-shaped molded product having two ribs 9a forming undercuts on the cavity side. FIG. 4 shows a mold device for the molded product 9 shown in FIG. 5, in which the IO has its upper end fixed to the stationary side mounting plate 12 by means of a back plate, and has a shaped portion at its lower end. Reference numeral 11 denotes a sliding insert having an undercut portion 11a, which is disposed within the cavity mold plate 13. A cylinder 14 is connected to the sliding insert 11 and fixed to the end surface of the cavity mold plate 13. 15 is a slide core that shapes the side wall of the molded product 9.

The operation of the mold apparatus configured as described above will be explained below.

First, when the mold is opened after filling with resin, the back plate 10 at the rear of the sliding insert 11 comes off from the cavity mold plate 13, the sliding insert 11 is pushed by the cylinder 14, and the molded product 9
0 Remove the undercut and release from the mold.

Problems to be Solved by the Invention However, with the above structure, when opening the mold, after removing the back plate, the sliding insert must be slid by the cylinder to remove the unarcut of the molded product.
This method has problems in that the mold opening stroke becomes long, the cylinder drive time is required, and the molding cycle becomes long.

Therefore, in view of the above problems, the present invention is capable of molding a molded product having a rib shape that forms an undercut on the cavity side without using a movable back plate or cylinder as in the conventional example, and also shortens the molding cycle. This provides a mold device that can be shortened.

Means for Solving the Problems In order to solve the above-mentioned problem, the hollow mold device of the present invention has the following features:
a slide block having a shaped part for forming an undercut part of a pre-shaped product; a biasing means for biasing the slide block in a mold opening direction; a guide support means that guides and supports the part so as to be slidable in a direction in which the part comes out; a stopper that stops the slide block that has been slid a certain distance by the biasing force; and a stopper that stops the slide block that has been slid a certain distance by the biasing force; The present invention is characterized by comprising a return means for dynamic return.

According to the above-mentioned structure, the present invention allows the slide block to slide in the direction guided by the guide support means by the biasing means in synchronization with the opening of the mold, thereby making it possible to remove the undercut on the cavity side of the hollow product. Therefore, it is extremely advantageous in shortening the cutting cycle.

Embodiment Hereinafter, a resin molding mold apparatus according to an embodiment of the present invention will be described with reference to the drawings.

In Fig. 1, numeral 1 is a hollow part having a rib 1a that serves as an undercut on the cavity side, and numeral 2 is a rod disposed at a certain angle with respect to the mold opening direction.
The upper end is fixed to. Reference numeral 3 denotes a spring, which is arranged around the outer periphery of the rod 2. Reference numeral 4 designates a slide block having a contact surface 4a for the spring 3 and a shaped portion 4b forming an undercut portion of the rib 1a on one side of the lower end. This slide block 4 is slidably guided in the above direction by having its sliding portion 4C held by a holding portion 5a of a slide guide plate 5 fixed to the cavity 8. A stopper 6 is fixed to the lower end of the lower end 5a of the slide guide plate 5 and stops the slide block 4 after sliding a certain distance.A stopper 7 resists the urging force of the spring 3 when the slide block 4 is closed. This is a 7a slide core that slides back into place. This slide core 7 is reciprocated in the lateral direction by a rod 8a extending obliquely downward from the cavity 8 as the mold opens and closes.

The operation of the resin molding device configured as described above will be explained.

FIG. 3 shows the molding die device when opening the mold,
When the mold is opened, the spring 3 is guided inside by the rod 2 and pushes down the slide block 4.

The slide block 4 has its sliding portion 4c supported by the holding portion 5a of the slide guide plate, and slides at a certain angle with respect to the mold opening direction. Also, after sliding a certain distance, the stopper 6
Stops due to By this operation, the rib-shaped undercut on the cavity side of the shaped product 1 is removed and the shaped product 1 is released from the mold. When closing the mold, the slide block 4 is pushed up by one surface 7a of the slide core 7 and returned to the position before opening the mold (mold closing completion position).

With the forming mold apparatus having the structure of this embodiment, there is no need to take a long mold opening stroke, and there is no delay in the molding cycle due to cylinder operation, so that the molding cycle can be shortened.

Effects of the Invention As described above, the present invention does not require a long mold opening stroke, there is no delay in the shaping cycle due to cylinder operation, the molding cycle can be shortened, and no cylinder is used, so the molding cycle can be shortened. Therefore, the cost of molded products can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of a resin molding mold device according to an embodiment of the present invention when the mold is closed, FIG. 2 is a cross-sectional view taken along the line nn in FIG. 1,
Figure 3 is a partial sectional view of the same round mold device when the mold is opened;
The figure is a partial sectional view of a conventional Kai-type mold device when the mold is closed.
The figure is a perspective view of a molded product having a lip forming an undercut on the cavity side, which was molded by the same molding die apparatus. 1... Molded product, 1a... Rib, 2...
...Rod, 3...Spring, 4...
Slide block, 4b...Shape part, 5...
...Slide guide plate, 6...Stopper
7...Slide core, 8...Cavity.

Claims (1)

[Claims] a slide block having a shaped part for forming an undercut part of a molded product; a biasing means for biasing this slide block in a mold opening direction; a guide support means that guides and supports the slide block so as to be slidable in a direction in which the slide block comes out; a stopper that stops the slide block that has been slid a certain distance by the biasing force; and a stopper that slides the slide block against the bias force when the mold is closed. A resin molding mold device comprising a return means for returning the mold.