JPH0129061Y2 - - Google Patents

Description

[Detailed explanation of the idea] (b) Industrial application fields The present invention relates to a plastic injection mold.

(b) Conventional technology When forming an undercut part in an injection molded product, a slide core is commonly used. An example of this is
It can be found in Publication No.-49171.

The mold described in the above-mentioned publication uses a slide core to approach the molded product from outside to form undercuts (holes) on both sides of the molded product. Therefore, it is necessary to secure space for the slide core on the outside of the molded product. The mold becomes larger.

(c) Problems to be solved by the invention The invention prevents the mold from increasing in size even when a slide core is added.

(d) Means for Solving the Problems In the present invention, back-to-back slide cores are provided in which undercut molding portions protrude in opposite directions in a core portion that constitutes a molding space on the outside thereof. A control block having a cam portion engaged with the slide core is moved as the mold is opened and closed, thereby causing the undercut molding portion to protrude and retract from the side surface of the core portion.

(e) Effects According to the above configuration, the slide core is disposed using the internal space of the molded product, so it is possible to downsize the mold.

(F) Example In the figure, 1 is a fixed type and 2 is a movable type.
The fixed mold 1 is on the cavity side, and the movable mold 2 is on the core side. A molding space 4 is formed between the core portion 3 of the movable mold 2 and the fixed mold 1, and injection molding of a molded product 5 is performed. The molded part 5 has symmetrical side walls 6, 6, as can be seen in FIG. Reference numerals 7 and 7 designate slide cores in which through-hole undercut portions 8 and 8 are formed in the side walls 6 and 6, respectively. The slide cores 7, 7 have a small diameter undercut molded part 9, on the end face of a large diameter cylindrical main body part.
The cylindrical storage chamber 1 in the core part 3 is shaped so that only the tips of the undercut molded parts 9, 9 protrude from both sides of the core part 3.
0 are stored back to back. 11 is a control block whose head is inserted into the center of the storage chamber 10 from the side. The control block 11 is slidable in a direction perpendicular to the sliding direction of the slide cores 7, 7, and is moved when the mold is closed or opened by the action of an inclined pin 12 protruding from the fixed mold 1. Control block 11
has two types of cam parts. Part 1 is a wedge-shaped cam part 13 protruding from the center of the end, which engages with the inclined surfaces 14, 14 at the ends of the slide cores 7, 7 and functions to push the slide cores 7, 7 outward. . The second part is cam parts 15, 15 formed apart from the cam part 13, protrudes in the direction of convergence with each other, and engages with the inclined holes 16, 16 of the slide cores 7, 7. The main role of the cam portions 15, 15 is to pull the slide cores 7, 7 inward.

In the mold having the above structure, when the mold is closed, the control block 11 pushes the slide cores 7, 7 outward as shown in FIGS. 1 and 2. This state is reliably maintained by the cam surface 17 of the stationary mold 1 which engages the control block 11 after the movement by the tilting pin 12 is completed. When injection molding is performed here, undercut portions 8, 8 are formed in the molded product 5. When the mold is opened as shown in FIG. 3 and FIG. The undercut molded parts 9, 9 are pulled toward the center and come out of the molded product 5. This allows the molded product 5 to be ejected.

(g) Effects of the invention In this invention, the slide cores, which should form undercuts on both side walls of the molded product, are placed in locations corresponding to the internal space of the molded product, thereby avoiding an increase in the size of the mold. I can do it. Furthermore, since the movement of the slide core is performed by the cam action of the control block, the movement is reliable.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, in which FIG. 1 is a partial sectional view when the mold is closed, and FIG. 2 is a sectional view taken along the line - in FIG. 1. FIG. 3 is a partial sectional view when the mold is opened, and FIG. 4 is a sectional view taken along the - line in FIG. 3. 1...Fixed type, 2...Movable type, 3...Core part,
7, 7... Slide core, 9, 9... Undercut molding section, 11... Control block, 12... Inclined pin.

Claims (1)

[Scope of utility model registration request] A fixed type, a movable type, a slide core housed in the core part of the movable type in a back-to-back manner with undercut molded parts protruding from both sides of the core part, and a slide core that is perpendicular to the sliding direction of the slide core. a control block that is slidable in the direction of the slide core, and that engages a cam portion with each of the slide cores to cause the slide cores to slide along with the slide cores; and a control block that connects the fixed mold and the control block; An injection molding mold equipped with an inclined pin that moves a control block as the mold closes and opens, thereby causing the undercut molding part of the slide core to protrude and retract from the core part.