JPH0521388Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an injection mold equipped with a submarine gate.

(Prior Art) Submarine gates are widely used as one type of gate in injection molds, as they have the advantages of easy removal of molded products and inconspicuous gate marks. In an injection mold equipped with such a submarine gate,
After injection molding, an ejector pin is used to eject the molded product, and at the same time, another ejector pin is used to eject the molding material filled in the runner (hereinafter referred to as the runner molded product).

As shown in FIG. 6a, the runner generally has a cold slag reservoir 21 formed at its tip, and a runner that extends to the submarine gate 22 at a predetermined acute angle with the cold slag reservoir 21 at the side thereof. A protruding pin 24 is formed with a leg portion 23 and protrudes from the runner molded product 5.
is located at the tip of the cold slag reservoir 21. Then, the ejecting pin 24 is pushed out, and the cold slag reservoir portion 5 of the runner molded product 5 is
By pressing a, the runner leg portion 5b of the runner molded product 5 is separated from the runner leg portion 23,
This allows the runner molded product 5 to be released from the runner 25.

(Problem to be solved by the invention) However, in the case of such an injection mold, when the runner molded product is released from the mold, the runner molded product accidentally pops out, causing damage to the opened mold. A problem has occurred in which the metal gets into the gap and gets caught in the mold when the mold is next clamped, causing damage to the mold. The reason why the runner molded product pops out is that when the runner molded product 5 is ejected, as shown in Fig. 6b,
The runner leg portion 5b begins to come off the runner leg 23 while being bent due to plastic and elastic deformation, and at the moment when the tip portion finally separates from the runner leg 23, the deflection due to the elastic deformation of the runner leg portion 5b is released. However, at this time, since the cold slag reservoir portion 5a has already separated from the cold slag reservoir 21, the runner molded product 5 is ejected from the mold by its elastic force.

This phenomenon of the runner molded product popping out is caused by the 6th
This is particularly noticeable in a runner molded product that has a pair of runner leg portions 5b on both sides and has a short pitch between the gates on both sides (that is, is relatively small and lightweight), such as the runner molded product 5 shown in Figure a. This phenomenon can similarly occur even when there is only one runner leg portion, and even in a somewhat large and heavy runner molded product.

The following types of molds particularly cause problems due to the runner molded product popping out. In other words, this protrusion is a problem in a mold consisting of a fixed mold, a movable mold that can move forward and backward relative to the fixed mold, and a sliding mold that can slide horizontally relative to the movable mold. . In general, in such a mold, the movable mold has a surface that makes sliding contact with the lower end surface of the slide mold, so when the mold is opened after injection and cooling, there is a difference between the movable mold and the slide mold. If a runner molded product projected by an ejector pin flies into the box-shaped space that is formed, the runner molded product will easily reach the surface of the movable mold that forms the lower end of the space (hereinafter referred to as the pocket section). ), and during subsequent mold clamping, the runner molded product gets caught in the mold, damaging the mold.

The present invention was devised in view of these circumstances, and provides an injection mold that will not be damaged even if the runner molded product is placed on the pocket part. The purpose is to provide the following.

(Means for Solving the Problems) The injection mold according to the present invention has an air outlet formed near the pocket of the movable mold, and blows air from the air outlet to the pocket. The runner molded product placed thereon is blown away, thereby preventing the runner molded product from getting caught in the mold, thereby achieving the above objective. In other words, injection molding is made up of a fixed mold, a movable mold that can move forward and backward with respect to the fixed mold, and a slide mold that can slide in the left and right directions with respect to the movable mold, and is equipped with a submarine gate. In the mold, an air outlet is formed in the vicinity of the pocket portion that is in sliding contact with the lower end surface of the slide mold and is exposed when the slide mold is opened, and the slide mold is connected to the movable mold. On the other hand, when the mold is opened, air is ejected from the air ejection port.

The above-mentioned "air outlet" blows out the "surface of the movable mold that comes into sliding contact with the lower end surface of the slide mold and is exposed when the slide mold is opened," that is, the runner molded product resting on the pocket part. As long as it can be removed, its shape, structure, number, etc. are not particularly limited, and it may be formed in the pocket portion or in the vicinity thereof. Regarding the ejection time, it is of course possible to eject continuously while the slide mold is opened relative to the movable mold, but it is also possible to remove the runner molded product from the pocket part. It may be a momentary eruption as long as it is a liquid.

(Function) With the above configuration, when the mold is opened after injection and cooling, a pocket part is formed in the movable mold, and a runner molded product leading to the submarine gate is protruded from the pocket part by a protruding pin. However, an air outlet is formed near the pocket, and when the slide mold is opened to the movable mold, air is blown out from the air outlet. , it becomes possible to blow away the runner molded product placed on the pocket and remove it from the pocket.

(Effects of the invention) Therefore, according to the invention, it is possible to prevent problems such as the runner molded product placed on the pocket part getting caught in the entire mold and damaging the mold. This makes it possible to improve production efficiency.

(Examples) Examples of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a perspective view showing essential parts of an embodiment of an injection mold according to the present invention, and FIG. 2 is a plan sectional view showing the overall structure of the mold.

As shown in FIG. 2, the injection mold consists of a fixed cavity block 10, a movable core 20, and a pair of sliding cores 30a and 30b. The slide cores 30a and 30b are adapted to slide in the left-right direction (direction B in the drawing) with respect to the core 20. These cavity block 10, core 20 and slide core 30
Molten resin is injected into a cavity 40 formed when molds a and 30b are clamped to form a spool 1 which becomes a core material for winding photographic film.

FIG. 3 is a side sectional view showing the spool 1 as a single item. As is clear from FIGS. 3 and 2, cylindrical shaft end recesses 1a and 1b are formed at both ends of the spool 1 in the axial direction. The shaft end concave portion 1a is shallower than the shaft end concave portion 1b, and a rib 2 is provided inside thereof to communicate between both walls of the shaft end concave portion 1a. Furthermore, inside the shaft end recessed portion 1b, a pair of ribs 3 facing each other are provided upright on both walls.
Rib 2 and rib 3 are formed in planes that are orthogonal to each other.

As shown in FIG. 2, each slide core 30a,
30b has a slide core pin 31 to be nested.
a and 31b are each fixedly installed. These slide core pins 31a, 31b form shaft end recesses 1a, 1b of the spool 1, respectively. Therefore, slits 32a and 32b corresponding to the ribs 2 and 3 are formed at the tip of each of these slide core pins 31a and 31b, respectively.

FIG. 1 shows the core 20 and slide cores 30a, 30 when the injection mold is opened.
It is a perspective view which shows b.

As shown in FIGS. 6a and 6b, the core 20 has an upper and lower surface from the submarine gate 22. A runner 25 serving as a passage for injecting molten resin into the pair of cavities 40 is disposed between the two cavities 40, and a plurality of sets of these cavities 40 and runners 25 are arranged in one vertical row. Therefore, when opening the mold after injection and cooling, multiple runners 2
A plurality of runner molded products 5 are ejected from the runner 5. And slide cores 30a, 30b
When the mold is opened by sliding on the core 20, a box-shaped space is formed by the slide cores 30a, 30b and the movable mold including the core 20. The molded product 5 is
It will rest on the movable mold surface (pocket portion) 26 located on both left and right sides of the lower end of the core 20 which slides into contact with the lower ends of the slide cores 30a and 30b and is exposed when the mold is opened.

However, in the injection mold according to this embodiment, the air outlet 27 is formed in the pocket portion 26, and the slide cores 30a, 30b are connected to the core 2.
When the mold is opened to 0, the air outlet 27
Since air is blown out from the pocket portion 26, the runner molded product 5 placed on the pocket portion 26 is blown away by the air and falls. The air ejected from the air outlet 27 is supplied from a compressor (not shown) via an air filter and a solenoid valve, and the timing of the air ejection is determined using a predetermined timer as shown in FIG. By controlling the opening and closing of the electromagnetic valve, the injection is continued from the middle of the mold opening operation to immediately after the mold closing operation is started.

As shown in FIG. 5, in an injection mold having a plurality of sets of core 20 and slide cores 30a, 30b, the plurality of air supply passages 28 leading to the air outlet 27 are arranged as appropriate depending on the mold structure. All you have to do is form it.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of essential parts showing an example of an injection mold according to the present invention, Fig. 2 is a plan sectional view showing the overall structure of the mold, and Fig. 3 is a perspective view of the main parts of an injection mold according to the present invention. Figure 4 is an explanatory diagram showing the function of the mold, Figure 5 is a view taken in the direction of Figure 1, showing the air supply path of the mold, and Figures 6a and 6b.
The figure is a side sectional view showing the vicinity of the submarine gate of the mold. 5... Runner molded product, 10... Cavity plate (fixed type), 20... Core (movable type), 22...
...Submarine gate, 25...Ranna, 26...
Pocket part, 27... Air outlet, 30a, 30
b...Slider core (slide type).

Claims (1)

[Claims for Utility Model Registration] A fixed mold 10, a movable mold 20 that is movable in the front and rear directions with respect to the fixed mold 10, a slide mold 30a that is slidable in the left and right directions with respect to the movable mold 20,
30b, and submarine gate 22
The injection mold is equipped with a mold for injection molding, wherein air is provided in the vicinity of the surface 26 of the movable mold 20 that is in sliding contact with the lower end surfaces of the slide molds 30a, 30b and exposed when the slide molds 30a, 30b are opened. An injection device characterized in that a jetting port 27 is formed and the air is jetted out from the air jetting port 27 when the slide molds 30a and 30b are opened relative to the movable mold 20. Molding mold.