JPH04316816A - Mold for injection molding - Google Patents

Abstract

PURPOSE:To provide the structure of a mold for an injection molded article, which has a plurality of undercuts parallel and normal to the mold opening direction of the mold and all the undercuts of which can be relieved at the mold opening. CONSTITUTION:A guide path 4 is engraved to the mold opening direction O on an inclined core 3, which is slidably mounted in a guide groove 2 engraved in the fashion inclining to the mold opening direction O in the movable mold 1 of an injection mold. At the same time, the head part 12a of an undercut forming pin 12, which is slidably arranged in a guide hole 10 engraved normal to the mold opening direction O in the movable mold 1, is slidably engaged with the guide path 4.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold, and more particularly to a mold for injection molded products having a plurality of undercuts.

0002

[Prior Art] For example, a synthetic resin injection molded product P is shown in FIG.
As shown in three examples of partially broken cross-sectional views in a), (b), and (c), when the container is approximately box-shaped, the undercut part is in part A as shown in figure (a). In addition, in addition to part A perpendicular to the mold opening direction O, if there is an undercut part B in the opposite direction, a known inclined core is used on the movable mold side to remove the undercut and release the mold. A method is being taken. In addition, as shown in figure (b), when this molded product P has an undercut C part in addition to A part, which is perpendicular to the direction of A part and the mold opening direction O, the movable mold A method is adopted in which the undercut of part A is removed and the mold is released using a slide member that moves inward.

However, as shown in Figure (c) in this type of molded product having an undercut part A, if the above-mentioned undercuts in parts B and C exist at the same time, the part A is As shown in the partial sectional view, after the molded product Po without the undercut A is removed from the mold, another part Aa is fitted and bonded into the drilled hole Ab in a separate process.

0004

[Problem to be solved by the invention] Therefore, in the latter case, it is necessary to prepare a separate part Aa and perform post-processes such as drilling and gluing, which not only increases costs but also reduces the degree of freedom in product design. was also restricted by it. This invention was made in view of the problems of the conventional method as described above, and as mentioned above, an injection molded product has a plurality of undercut portions in the opening direction of the mold and in the direction perpendicular to the mold opening direction. The purpose of the present invention is to provide a mold structure that can release all of the molds when the mold is opened.

[0005]

[Means for Solving the Problems] Therefore, in the present invention, a guide groove is formed in a movable mold of an injection mold so as to be slidable with respect to the mold opening direction. A guide track is provided in the mold opening direction on the tilted core, and an undercut forming pin is slidably disposed in a guide hole carved in the movable mold in a direction perpendicular to the mold opening direction. This object is achieved by configuring the head to slidably engage within the guide track.

[0006]

[Operation] With the mold configuration as described above, when the inclined core slides in the guide groove in the direction opposite to the mold opening direction by the protruding plate means during mold release, the inclined core engages with the guide track on the inclined core. The undercut forming pin is pulled out and withdrawn in the vertical direction by the combined heads, and the other undercut parts can be simultaneously released by the conventional method. The injection molded product can be completely released from the mold at the same time during the mold opening process.

[0007]

EXAMPLES The present invention will be explained below based on examples. FIGS. 1A and 1B are sectional views showing essential parts of an embodiment of an injection mold according to the present invention in a closed state and in a state immediately before releasing a product after opening the mold. (Configuration) P is a box-shaped container-shaped synthetic resin injection molded product, A, B
are each undercut portion facing perpendicularly to the mold opening direction O of the molding die (only the movable die 1 is shown), C
indicates an undercut portion in the same direction as the mold opening direction O. 2
is a guide groove carved inside the movable mold 1 so as to be inclined with respect to the mold opening direction O, and an inclined core 3 is slidably disposed within the groove 2. The inclined core 3 has a guide track 4 carved in the mold opening direction O, and when the mold is opened, the inclined core protruding plate 6 disposed on the movable mold mounting plate 5 shown in the lower part of the figure (b) It is configured to be projected in a direction opposite to the mold opening direction O. 7 is the extrusion rod. These mechanisms are configured in a two-stage operation type with mechanisms such as an ejector plate extrusion plate 9 for the ejector plate 8 for mold release and its extrusion rod 10. On the other hand, 11 is a moving mold 1
With a guide hole drilled inside in a direction perpendicular to the mold opening direction O,
An undercut forming pin 12 for the undercut A portion is slidably disposed inside it, and its head 12a is
It is slidably engaged within the guide rail 4.

(Operation) (a) After injection is performed in the state shown in the figure, when the mold is opened, the undercuts B and C are formed by the conventional method (not shown), and the undercut A is formed by the conventional method (not shown). (b) As shown in FIG. ), the molded product is withdrawn and removed from the undercut portion of the molded product, so that it can be released from the mold without any trouble by the operation of the injector plate 8 in the next step.

(Other Embodiments) In the above embodiments, the molded product P has three undercut portions A, B, and C, but the present invention is not limited to this. It can also be applied to multiple different cases.

0010

[Effects of the Invention] As explained above, according to the present invention, a guide track for withdrawing the undercut forming pin in conjunction with the movement of the inclined core is provided in the movable mold. It is now possible to simultaneously release an injection molded product having an undercut portion from the mold during the mold opening process, thereby improving the degree of freedom in product design without increasing production costs.

[Brief explanation of drawings]

FIG. 1 is a cutaway sectional view of essential parts of an embodiment of an injection mold in a closed/opened state.

[Fig. 2] Three examples of partially cutaway cross-sectional views of injection molded products having undercut parts.

FIG. 3 is an explanatory diagram of a conventional method of using separate parts.

[Explanation of symbols]

A, B, C Undercut P Injection molded product 1. Moving mold 2 Guide groove 3 Inclined core 4 Guide orbit 11 Guide hole 12 Undercut forming pin 12a Head

Claims (1)

[Claims] 1. A guide in the mold opening direction on an inclined core that is slidably mounted in a guide groove carved in the movable mold of the injection mold at an angle with respect to the mold opening direction. A track is provided, and the head of an undercut forming pin, which is arranged to be slidable within a guide hole carved in the movable mold in a direction perpendicular to the mold opening direction, is slidable within the guide track. An injection mold characterized in that the molds are engaged with each other.