JPH0427631Y2 - - Google Patents

Description

[Detailed explanation of the idea] "Industrial application field" The present invention relates to an injection mold.

"Prior Art" An example of this type of injection mold is shown in FIGS. 3 to 6.

In Fig. 3, numeral 1 is the fixed side mounting plate, 2 is the runner stripper plate, 3 is the fixed side template, and 4 is the fixed side mounting plate.
5 is a movable side mold plate, 5 is a spacer, and 6 is a movable side mounting plate. A cavity 7 is defined between the stationary mold plate 3 and the movable mold plate 4, 8 is a sprue, and 9 is a runner that communicates the sprue 8 with the injection port 10.

FIG. 4 shows another cross section of this mold. Between the movable side mold plate 4 and the fixed side mold plate 3, a plurality of plastic bolts 11 (only one is shown) are inserted into the mold. It is slidably penetrated in the opening direction. The movable end of the plastic bolt 11 is provided with an elastic locking portion 12 that locks the movable mold plate 4 when the mold is opened.
On the other hand, a collar portion 13 that engages with the stationary template 3 is formed at the stationary end. The elastic locking part 1
2, as shown in FIG. 6, a cushion material 14 and a pair of rings 15, 15 sandwiching the cushion material 14;
A bolt 16 passed through is screwed into the end of a plastic bolt main body 17.

On the other hand, a plurality of similar plastic bolts 18 (only one is shown) are attached between the stationary template plate 3 and the runner stripper plate 2, and one end of the plastic bolts 18 is fixed to the runner stripper plate 2. At the same time, an elastic locking portion 12 at the other end locks the stationary mold plate 3 when the mold is opened.

In such a mold, when the mold members 2, 3, and 4 are separated from each other by a drive mechanism (not shown) when the mold is opened, the plastic bolt 1 is removed as shown in FIG.
The movable template 4 is secured by the elastic locking portions 12 of 1 and 18.
and fixed side template 3 are respectively locked, and the amount of separation from each other is regulated. Also,
At this time, the cushion material 14 of the elastic locking portion 12 elastically contracts, thereby making it possible to reduce the impact of opening the mold and prevent noise.

"Problem to be solved by the invention" By the way, in the case of the above mold, the amount of shrinkage of the cushion material 14 of the plastic bolts 11, 18 is equal to the tensile force applied to the plastic bolts 11, 18 when the mold is opened. It changes depending on. For this reason,
If the force applied to the plastic bolts 11, 18 provided between the same mold members 3, 4 or 2, 3 varies, the effective lengths of the plastic bolts 11, 18 will become uneven, and the mold members 3, 4, 2 , 3 had the disadvantage that the mutual parallelism, that is, the mold balance deteriorated.

"Means for Solving the Problems" The present invention solves the above problems and is characterized by providing a stopper that limits the maximum amount of deformation of the elastic locking portion of the plastic bolt.

"Example" Hereinafter, an example of the present invention will be described in detail using FIGS. 1 and 2.

These figures show essential parts of an injection mold according to an embodiment, in which reference numeral 4 is a movable mold plate, and 21 is a plastic bolt having an elastic locking portion 22. This embodiment is characterized by the elastic locking portion 22, and the other configurations of the mold are the same as those of the conventional one.
The explanation will be omitted.

The elastic locking part 22 is a circular plastic bolt body 2.
The ring 2 is attached to the narrow diameter portion 23A formed at one end of the ring 3.
4 and a cylindrical stopper 25 are slidably passed through the stopper 25, a cylindrical cushioning material 27 is placed over the outer periphery of the stopper 25, and a ring 27 that presses the cushioning material 26 is attached to a bolt 29 through which a spring washer 28 is passed. Therefore, it is fixed to the end face of the narrow diameter portion 23A.

The inner diameter of the ring 24 is approximately equal to the outer diameter of the narrow diameter portion 23A, and the outer diameter is larger than the diameter of the plastic bolt through hole 4A of the movable template.

The stopper 25 is made of a hard material such as metal, and its length is determined by the distance between the cushion material 2 and the movable template 4 and the fixed template (not shown).
6 by a predetermined length T (maximum deformation amount). Further, the inner diameter of the stopper 25 is approximately equal to the outer diameter of the narrow diameter portion 23A, and the outer diameter thereof is approximately equal to the inner diameter of the cushion material 26.

The cushion material 26 is made of an elastic material such as rubber or resin, and its length is approximately equal to the length of the narrow diameter portion 23A minus the wall thickness of the ring 24. In addition, cushion material 26
When the mold is opened by a drive mechanism (not shown), the ring 24 is moved to the stopper 2 as shown in FIG.
It is desirable that the elasticity is as high as possible in the range where it contacts the end surface of 5.

In an injection mold with such a configuration,
When the elastic locking portion 22 of the plastic bolt 21 locks the movable mold plate 4 when the mold is opened, the cushion material 26 elastically contracts to cushion the impact and prevent the generation of noise.
At this time, the elastic locking portion 22 will not be compressed by the stopper 25 beyond the predetermined length T, so even if there is slight variation in the tensile force applied to each plastic bolt 21, the effective length of each plastic bolt 21 will always be the same. It will be kept constant. Therefore, according to this mold, it is possible to accurately maintain the distance between the mold members when the mold is opened, and it is possible to improve the parallelism of the mold members, that is, the mold balance.

Furthermore, in the mold of this embodiment, since the stopper 25 is covered with the cushion material 26, even if some noise is generated when the stopper 25 and the ring 24 come into contact, the noise will be absorbed by the cushion material 26. It has the advantage that it can be absorbed by twisting.

In the above embodiment, the stopper 25 is provided inside the elastic locking portion 22, but the present invention is not limited to this, and the stopper that locks the plastic bolt body 23 at a predetermined position is provided with an elastic lock. It may also be configured to be provided outside the section 22.

"Effect of the invention" The injection mold of the invention is equipped with a stopper that limits the maximum deformation of the elastic locking part of the plastic bolt, so the effective length of the plastic bolt determines the distance between the mold members. is always kept constant even if there are slight variations in the tensile force applied to each plastic bolt. Therefore, it is possible to accurately maintain the distance between the mold members when the mold is opened, and it is possible to improve the parallelism of the mold members, that is, the balance of the mold.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the main parts of an injection mold according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the function of the main parts. Further, FIGS. 3 to 5 are sectional views of a conventional injection mold, and FIG. 6 is a sectional view of a main part of the same mold. 4...Movable side mold plate (mold member), 21...Plastic bolt, 22...Elastic locking part, 25...Stopper, 26...Cushion material, T...Maximum deformation amount of the elastic locking part.

Claims (1)

[Claims for Utility Model Registration] It has a plurality of mold members that are separated from each other when the mold is opened, and these mold members have plastic bolts provided with elastic locking portions at the ends that are slidable in the mold opening direction. In an injection mold, the distance between the mold members is regulated by the mold member elastically abutting the elastic locking portion of the plastic bolt when the mold is opened. An injection molding die characterized in that a stopper is provided to limit the maximum amount of deformation of an elastic locking part.