JPS6219422A - Injection molding equipment - Google Patents

Abstract

PURPOSE:To accelerate the release and falling of a molded part with undercut and achieve the continuation of production by a method wherein vibration is given to ejector pins after the finish of a single ejection developed by the opening of a mold by providing vibrating elastic bodies and a single acting cylinder in addition to a mechanical ejecting mechanism. CONSTITUTION:Firstly, a mold is open until a stop pin 7 has somewhat of allowance of movement (beta) with respect to a stop block 8 and the release of a molded part 1 from the mold is completed. Secondly, the rod 11 of a single acting cylinder 10 is advanced in accordance with a mold-opening completion signal so as to press an ejector plate 5 and retreated immediately after the pressing of the ejector plate in order for the ejector plate 5 to be pushed back to its initial position by vibrating springs 9. the pressing and pushing-back of the ejector plate as just described above is repeated by a plurality of times with minute stroke so as to give vibration to ejector pins 4 in order for the molded part 1, which is not allowed to fall down even after the release from the mold by sticking to the tip surfaces of the ejector pins or by coming pinched by a plurality of pins under the condition that the surface of the molded part becomes lower than the tips of the pins, to separate from the pins and to accelerate the falling of the molded part by gravity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a mold release means for an injection molding apparatus having a plurality of mold clamping mechanisms.

(Background Art) FIG. 3 shows a conventional mold opening process in an injection molding apparatus having a plurality of mold clamping mechanisms, which can cope with the case where a molded product has an undercut portion. In the figure, 2A, 2B, and 2C are the molds in the A direction, B direction, and C direction, respectively, and 3A, 3B, and 3C are the molds in the A direction, B direction, and C direction, respectively.
1 is a mold opening/closing arm in the C direction, and 1 is a molded product having an undercut portion 1 & in the C direction. Further, 4 is an ejector pin for ejecting the molded product, 5 is an ejector plate to which the ejector pin 4 is attached, 6 is a holding spring that presses the ejector plate 5 downward, 7 is a stop pin fixed to the ejector plate 5, 8 is the stop block in the rest position, and the ejector pin 4. The ejector plate 5, the holding spring 6, the stop pin 7, and the stop block 8 constitute a mechanical ejection mechanism.

Figure 3 (A) shows the state where mold clamping has been completed and molding has been carried out, but in the case of mold release, as shown in (B) (minimal amount at!
The ejector pin 4 is used to open the mold in the C direction to make the C direction unloaded and to protect the undercut portion 1a.
The molded product 1 is placed in a stationary state with the part protruding by the amount a, and in this state, the mold is opened in the entry direction and the B direction as shown in (c), and then,
The mold is opened again in the C direction and the molded product 1 is ejected using the ejector pin 4.

By the way, in the conventional method as described above, the ejector pin 4 of the mechanical ejection mechanism protrudes relatively as the mold opens in the C direction, and remains stationary with respect to the molded product 1. If the molded product 1 is attached to the tip of the molded product 4 or if the molded product is caught in the molded product, the molded product 1 may not fall naturally, and the release operation due to ejection may not be stable. This was a hindrance to continuous molding.

(Object of the Invention) The present invention has been proposed in view of the above points, and its purpose is to improve the stability of mold release drop in the case of a molded product having an undercut portion by multi-directional mold clamping. The object of the present invention is to provide an injection molding device that can achieve continuous production.

(Disclosure of invention) Hereinafter, the present invention will be described in detail with reference to the drawings showing examples.

FIG. 1 shows an embodiment of the present invention, and only shows the structure near the mold in an injection molding apparatus. In the figure, 2A, 2B, and 2C are the molds in the A direction, B direction, and C direction, respectively, and 3A, 3B, and 3C are the molds in the A direction, B direction, and C direction, respectively.
1 is a mold opening/closing arm in the C direction, and 1 is a molded product having an undercut portion 1a in the C direction. Further, 4 is an ejector pin for ejecting the molded product, 5 is an ejector plate to which the ejector pin 4 is attached, 6 is a holding spring that presses the ejector plate 5 downward, 7 is a stop pin fixed to the ejector plate 5, 8 is the stop block in the rest position, and the ejector pin 4. Ejector plate 5. The holding spring 6, stop pin 7, and stop block 8 constitute a mechanical ejecting mechanism.

The above configuration is similar to that shown in FIG. 3, but in the present invention, a vibration spring 9 is further provided coaxially with the ejector pin 4 between the ejector plate 5 and the inner bottom surface of the mold 2C.
A single-acting cylinder 10 is arranged above the ejector plate 5, and the ejector plate 5 is struck by the vertical movement of the rod 11 of the single-acting cylinder 10.

The process from mold clamping to mold opening is the same as that shown in Fig. 3, and when the mold opening is completed, ejection is performed only once in conjunction with the movement of the mold opening/closing arm 3C in the C direction. It is. However, regarding the holding spring 6, whereas in the conventional device shown in FIG. The present invention is different in that when the mold opening in the C direction is completed, the holding spring 6 is in a free state with respect to the ejector plate 5, or in a nearly free state to the extent that it does not displace the vibration spring 9 significantly.

Further, the stop pin 7 has opened the mold to a state where it has some margin β with respect to the stop block 8, and in this state, the release of the molded product 1 from the mold part is completed.

Thereafter, the rod 11 of the single-acting cylinder 10 moves forward in response to the mold opening completion signal, presses the ejector plate 5, and retreats, and the ejector plate 5 is returned to its original position by the vibration spring 9.

By repeating this multiple times with small strokes and applying so-called vibration, the ejector pin 4 may stick to the tip surface, or the pin tip surface may be lower than the molded product surface and may become wedged between multiple pins. The molded product 1, which has been released from the mold but cannot be dropped, is separated, and the falling of the molded product 1 due to its own weight is promoted. Naturally, both the holding spring 6 and the vibration spring 9 have countersunk holes for receiving the bottom of the spring, but since the top of the spring may become free and fall or jump out, they are held by the bottom of the spring. It looks like this.

It goes without saying that the above structure can be similarly applied to directions other than the C direction as needed.

Next, FIG. 2 shows another embodiment of the present invention, in which a vibration urethane rubber 12 is provided below the ejector plate 5 instead of the vibration spring 9 in FIG. . That is, the elasticity of the vibration urethane rubber 12 is used to generate vibrations. Note that the operation is similar to that shown in FIG.

(Effects of the Invention) As described above, in the present invention, in an injection molding apparatus having a plurality of mold clamping mechanisms whose mold opening/closing order can be set, in addition to a mechanical ejecting mechanism, a vibrating elastic body and a single-acting A cylinder is arranged to apply vibration to the ejector bin after the mold is opened and ejected only once, which helps molded products with undercuts fall from the mold and achieves continuous production. There is.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram showing another embodiment, and FIG. 3 is a diagram showing the mold opening process in a conventional device. 1...Molded product, 1m...Undercut part, 2A. 2B, 2C・・・Mold, 3 people, 3B, 3C
...Mold opening/closing arm, 4...Ejector bin, 5...Ejector plate, 6...
...Holding spring, 7... Stop pin, 8...
... Stop block, 9 ... Vibration spring,
lO...Single acting cylinder, 11...Rod, 12...Urethane rubber for vibration

Claims (1)

[Claims] This is an injection molding machine that has multiple mold clamping mechanisms whose mold opening/closing order can be set and is variable, and which starts mold release on a parting center and uses a method in which the molded product falls under its own weight. It consists of a holding spring, a stop pin, and a stop block. In addition to the mechanical ejection mechanism, a vibrating elastic body is provided in front of the ejector plate, and a single-acting cylinder is placed behind the ejector plate. An injection molding device characterized by applying vibration to an ejector plate with a single-acting cylinder in a state similar to that, to promote release and fall of the molded product.