JPH04212817A - Mold for resin molding machine - Google Patents

Abstract

PURPOSE:To aim at the positive injection of a molded product regarding the injection mechanism of the molded product of a resin molding machine. CONSTITUTION:A mold for a resin molding machine has an injection pin extruding a molded product from a mold, and the mold for the resin molding machine is constituted while providing a plurality of rod pins having means 12b, 11f moved forward in the same direction as being synchronized with the injection pin 12a when the injection pin 12 is forwarded and extrudes the molded product from the mold while capable of being retreated only by external force applied in the direction of retreat when said injection pin 12a is retreated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for a resin molding machine equipped with an eject mechanism for reliably ejecting a molded product from the mold.

[0002] In order to take out a molded product from a mold in a resin molding machine, a method is usually adopted in which the molded product is pushed out using an eject pin provided in the mold. Since there are cases where it is not possible to remove it, a solution is desired.

0003

[Prior Art] Figure 2, which shows the main parts in cross section, is a conceptual diagram explaining the mold mechanism of a conventional resin molding machine. (a) shows the state during molding, and (b) shows the molded product. Indicates the state at the time of ejection. Figure 3 also shows a similar cross section.
is a diagram showing a problem.

In the drawings, for ease of understanding, a case will be described in which a circular cover (hereinafter simply referred to as "cover") 1 shown in a perspective view is used as a product. In FIG. 2(a), a cavity 2a corresponding to the outer shape of the cover 1 is formed in the mold 2, and a cover is provided at a position corresponding to the cavity 2a of the mold 3 facing the mold 2. A core 3a corresponding to the inner shape of 1 is formed. When the molds 2 and 3 are brought into close contact with each other while facing each other, a space region corresponding to the required cover 1 is formed between the cavity 2a and the core 3a.

On the other hand, in the space 3b provided on the back side of the core 3a of the mold 3, an arrow a is formed by a mechanism (not shown) at least by a distance exceeding the thickness t of the cover 1.
An eject plate 4 is provided which can move forward and backward in the direction toward the mold 2 as shown in FIG.
It is constantly pressed in the a1 direction by two coil springs 5 (in the figure) and is positioned on the inner wall surface 3c of the mold 3.

Furthermore, in the area where the core 3a of the eject plate 4 exists, a plurality of (two in the figure) eject pins 4b are set perpendicularly to the eject plate 4, and the eject pins 4b are made of gold. It is designed to fit into a through hole 3d drilled at a corresponding position in the mold 3. The tip of the eject pin 4b is set so as to substantially coincide with the surface of the core 3a when the eject plate 4 is in the positioning position.

Therefore, after applying a mold release agent to the inner surface of the cavity 2a of the mold 2, the molds 2 and 3 are brought into close contact with each other, and a predetermined resin is injected into the above-mentioned space area from a runner (not shown). Form the cover shown.

[0008] Next, as shown in (b), when the mold 2 is moved back in the direction of the arrow b1 by a mechanism (not shown), the cover 1a is separated from the cavity 2a and remains on the core 3a side. Therefore, when the eject plate 4 is moved in the direction a2 against the coil spring 5, the tip of the eject pin 4b is moved toward the cover 1a.
Since the inner surface of the cover 1a is pressed in the a2 direction, only the cover 1a is taken out from the core 3a, but as soon as the pressing of the eject plate 4 in the a2 direction stops, the eject plate 4 is retreated to its original position by the coil spring 5. The cover 1
Only part a falls and the required cover 1 can be obtained.

However, when the cover 1a is light or the diameter of the eject pin 4b is large compared to the size of the cover 1a, the cover 1a is
In some cases, the cover 1a returns to the a1 direction while remaining in close contact with the core 3a, resulting in the state shown in FIG. Furthermore, when the mold 2 in the continuous molding process moves in the b2 direction and returns to the initial molding state, subsequent molding may be interrupted or the core 3a may be damaged.

0010

[Problems to be Solved by the Invention] With conventional resin molding machines equipped with mold mechanisms, it is not possible to take out the product after molding, which may interrupt subsequent molding or damage the core, reducing productivity. The problem was that we could not expect any improvement.

[0011]

[Means for solving the problem] The above problem is a mold for a resin molding machine equipped with an eject pin for extruding a molded product from the mold. A mold for a resin molding machine that includes a plurality of rod pins that move forward in the same direction in synchronization with the eject pin, and have means that allow the eject pin to retreat only by an external force applied in the retreating direction when the eject pin retreats. achieved by.

0012

[Operation] By configuring the mold mechanism of the resin molding machine so that the pin reliably separates from the molded product when the eject pin retreats, it is possible to prevent close contact between the eject pin and the molded product.

In the present invention, the mold mechanism is provided with a rod pin configured to move forward together with the eject pin to extrude the molded product and to hold the molded product in that position when the pin retreats.

Therefore, it is possible to obtain a highly productive resin molding machine equipped with a mold mechanism that can reliably drop the molded product when the eject pin is retracted.

[0015]

[Example] Fig. 1 is a configuration diagram illustrating a mold of a resin molding machine according to the present invention, and (A) shows the state during molding.
(B) represents the state of the molded product at the time of ejection.

In the figure, a case is explained in which a circular cover (hereinafter simply referred to as cover) 1 similar to that shown in FIG. 2 is used as a product. In FIG. 1A, a core 11a corresponding to the inner shape of the cover 1 is formed at a position corresponding to the cavity 2a of the mold 11 facing the mold 2 described in FIG. 2, a space region corresponding to the required wall thickness of the cover 1 is formed between the cavity 2a and the core 11a when the cores 11 are brought into close contact with each other in a state where they face each other. The same is true.

On the other hand, in the space 11b provided on the back side of the core 11a of the mold 11, an eject plate 12 that can move back and forth in the direction of the arrow a is provided, as explained in FIG. Similarly to FIG. 2, the plate 12 is always pressed in the a1 direction by a plurality of (two in the figure) coil springs 13 and is positioned by the inner wall surface 11c of the mold 11.

In particular, the eject plate 12 in this case includes:
In the area where the core 11a exists, there is an eject pin 12a similar to the eject pin 4b explained in FIG. Rod ejector pins 12b each having a shorter length are erected perpendicularly to the eject plate 12.

The eject pin 12a is inserted into the through hole 1 drilled at the corresponding position of the mold 11.
1d, and the rod extrusion pin 12b has a diameter larger than that of the rod extrusion pin 12b and is inserted into the core 11a at the corresponding position of the mold 11.
It is designed to be able to move forward and backward within a through hole 11f in which a flange 11e that protrudes inward is formed at the side opening.

The length of the eject pin 12a is set so that the tip of the pin 12a coincides with the surface of the core 11a when the eject plate 12 is at the positioning position, as in FIG. When the eject plate 12 is in the positioning position, the tip of the rod ejecting pin 12b is inserted into the through hole 11f.
The length is set so that it slightly penetrates inside.

Further, inside the through hole 11f, a rod pin 14 having a flange 14a at one end is installed.
The rod pin 14 is arranged so that it can move freely forward and backward toward the rod ejecting pin 12b, and the rod pin 14 is located at the tip of the rod ejecting pin 12b when the eject plate 12 is in the positioning position. The length is set such that the tip of the rod pin 14 coincides with the end surface of the cover 1a when the flange 14a of the rod pin 14 is brought into contact with the rod pin 14.

Therefore, as in the case of FIG. 2, after applying a mold release agent to the inner surface of the cavity 2a of the mold 2, the mold 2 and the mold 11 are brought into close contact with each other, and a predetermined resin is injected from a runner (not shown). A cover shown as 1a is molded.

Next, when the mold 2 is moved back in the direction of arrow b1 by a mechanism (not shown), the cover 1a closes in the cavity 2a.
It is released from the mold and remains on the core 11a side. Therefore, when the eject plate 12 is moved in the a2 direction against the coil spring 13, the tip of the eject pin 12a presses the inner surface of the cover 1a in the a2 direction, and the rod ejecting pin 12b
presses the end face of the cover 1a in the direction a2 via the rod pin 14, so that the cover 1a can be released from the core 11a.

After that, when the pressing of the eject plate 12 in the a2 direction stops, the eject plate 12 is moved back to its original position by the coil spring 13, so that the eject pin 12a
and the rod push-out pin 12b return to their initial positions, resulting in the state shown in (B), but in this case the rod pin 14 remains at the position moved by the rod push-out pin 12b.

[0025] Therefore, the cover 1a shown by the broken line, which is trying to retreat together with the eject pin 12a, is obstructed by the rod pin 14, and as a result, it falls as indicated by the arrow c, and the desired cover 1 can be obtained. .

Note that when the mold 2 in the continuous molding process automatically moves in the b2 direction and returns to the initial molding state, the rod pin 14 is pressed and moved by approximately half of its end surface. ) can be returned to the initial state shown in .

[0027]

As described above, according to the present invention, it is possible to provide a resin molding machine equipped with a mold mechanism that can reliably take out a molded product.

[0028] In the description of the present invention, the product to be molded is a circular cover, but by setting the length of the rod pin and its placement position according to the product shape, the same can be applied to molded products of any shape. effect can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram illustrating a mold of a resin molding machine according to the present invention.

FIG. 2 is a conceptual diagram illustrating a mold mechanism of a conventional resin molding machine.

FIG. 3 is a diagram showing problems.

[Explanation of symbols]

1, 1a Circular cover (product) 2,11 Mold 2a Cavity 11a Core 11b Space part 11c Inner wall surface 11d, 11f Through hole 11e Tsuba 12 Eject plate 12a eject pin 12b Rod extrusion pin 13 Coil spring 14 Rod pin 14a Flange

Claims (1)

[Claims] 1. A mold for a resin molding machine, comprising an eject pin for extruding a molded product from the mold, wherein when the eject pin (12a) moves forward to extrude the molded product from the mold, the eject pin (12a) ) are provided with a plurality of rod pins (14) having means (12b, 11f) that move forward in the same direction in synchronization with the eject pin (12a) and that can be moved back only by an external force applied in the backward direction when the eject pin (12a) is moved back. A mold for a resin molding machine, which is characterized by being composed of: