JPS5922713A - Undercut processing device of plastic molding tool - Google Patents

Abstract

PURPOSE:To obtain the titled device by a method wherein a movable split core, which shifts laterally with respect to the direction to open and close a mold by means of an inclined pin, is provided and a core for making inclined hole or recess is shifted along the direction of the hole or the inclination of the recess by means of said movable split core. CONSTITUTION:When a movable force 5 is lowered after the resin poured in a cavity 6 sets, a resin molded piece 2 lowers apart from a fixed force 4 and together with the movable force 5 by adhering thereon. At this time, a movable split core 12 is shifted rightward by sliding onto an inclined pin 9. Because the pin 19 of a movable core 18 slides along the inclined guide groove 16 of the movable split core 12 with said rightward shifting thereof, the movable core 18 is shifted in the direction as indicated with the arrow A, resulting in pulling the small diametral part 18a at the tip of the movable core 18 out of the molded piece 2. Consequently, the molded piece 2 can easily be released from the movable force 5. In order to clamp the molding tool, the above-mentioned procedure is reversed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an undercut treatment device for a mold for molding a plastic molded product having a hole or four parts that are inclined with respect to the opening/closing direction of the mold and are an undercut.

[Technical background of the invention]

When molding a plastic molded product with a hole or a recess that faces right sideways to the opening and closing direction of the mold, the hole or recess becomes an undercut and cannot be removed from the mold.

In such a case, one mold is provided with an inclined pin, and the other mold is provided with a core for forming the holes or four parts so as to be movable in the lateral direction with respect to the opening and closing direction of the mold, so that the core is tilted when the mold is opened. The core can be extracted from the hole or quadrant by being configured to slide laterally along the pin. However, if the holes or the four parts are inclined with respect to the opening/closing direction of the mold, it becomes impossible to perform mold cutting using the above-mentioned combination of inclined pins and core barbs. Therefore, conventionally, the core for molding the hole or the four parts is moved by a hydraulic cylinder, and after molding, the core is first moved by the hydraulic cylinder and extracted from the hole or the four parts, and then the mold is opened and the plastic is made. I'm trying to take out the molded product.

[Problems with background technology]

A dedicated pressure oil supply mechanism for the hydraulic cylinder must be provided only for cutting out the core for forming the hole or recess;
There was a problem that equipment costs were high. In addition, since the mold can only be opened after the core has been punched out, a two-stage operation is required, which lengthens the entire molding time, resulting in poor productivity.

[Purpose of the invention]

The present invention provides an undercut for plastic molds that can perform mold removal from an inclined hole or recess by using the mold opening operation, eliminates the need for a dedicated pressure oil supply mechanism, and improves productivity. The purpose is to provide processing equipment.

[Summary of the invention]

The present invention provides a movable core that is moved laterally with respect to the opening/closing direction of the mold by a tilting pin, and the movable core cleans the core for molding the hole or recess to be tilted in the direction of the tilt of the hole or four parts. By having a moving configuration, the core can be extracted from the inclined hole or the four parts at the same time as the mold opening operation using the mold opening operation.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. In Fig. 1, reference numeral 1 denotes a mold for molding a plastic molded product, for example, a front panel 2 of a washing machine operating box. It consists of 5. The fixed mold 4 and the movable mold 5 are formed with a recess 4a and a protrusion 5a that match the surface shapes of the outer and inner surfaces of the front panel 2, respectively, and a front spring is inserted between the recess 4a and the protrusion 5a. /
A cavity 6 matching the shape of L/2 is formed.

The front panel 2 has a boss 2a for attachment to the operation box, and a hole 7 at the lower end of the attachment boss 2a, which serves as a pilot hole for a self-tapping screw for fixing. This hole 7 is inclined downward to the right with respect to the vertical direction, which is the opening/closing direction of the movable mold 5, and therefore the hole 7 becomes an undercut for the mold 1. In the undercut processing device 8 for such a hole 7, 9 is an inclined pin attached to one of the fixed molds 4, and this inclined pin 9 is tilted toward the lower end in a lower right position, and its lower half is It protrudes toward the movable mold 5 side. 10 is movable type 5
A notched recess is formed on the right side of the recess, the lower part of which extends deeper leftward than the upper part, and grooves 11 are formed on both sides of the bottom. Reference numeral 12 denotes a movable core, which has an inclined hole 13 formed therein corresponding to the inclined pin 9, and a protrusion 14 (on one side) corresponding to the groove 11 at the lower end of both the front and rear sides, as shown in FIG. (Only shown) is provided protrudingly.

Further, at the lower left side of the movable mold 5, a pair of protrusions 15 facing each other at a predetermined interval in the front and rear are fixed, and a guide groove 16 that is inclined downward to the left serves as a guide portion that inclines in a predetermined direction in both protrusions 15.
is formed. The movable core 12 is connected to the protrusion 14 in the groove 1.
1, and is housed in a cutout recess 10 of a movable mold 5, so that it can be reciprocated in the left and right directions. And when the mold is closed as shown in Figure 1,
The lower half of the inclined pin 9 is fitted into the inclined hole 15.

17 is a stopper plate attached to the right side of the fixed mold 4, which is attached to the movable core 12 on the inclined UTJ 17a inside the lower end.
The movable core 12 is brought into contact with the upper right inclined surface 12a of the movable core 12.
This is used for positioning. Reference numeral 18 denotes a movable core, which has a stepped shaft shape as shown in FIG. 3, and has a pin 19 as a retaining portion inserted through its lower end. 20 is a guide hole for the movable core 18 formed in the movable mold 5;
It is inclined in the same direction as the hole 7, and both ends thereof are open to the inner lower part of the gear upper tee 6a for the mounting boss 2a and the lower inner deep part of the notched recess 10 of the movable mold 5. The movable core 18 is fitted into the guide hole 20 so as to be movable along the inclination of the guide hole 20 so that both ends of the pin 19 are inserted into and engaged with the guide groove 16 of the movable core 12. In the closed state of the mold shown in FIG. 1, the small diameter portion 18 acts as a mold for the hole 7.
In this state, the lower end of the movable core 18 comes into contact with the inclined surface 12t at the lower left side of the movable core 12, and the movable core 18 is positioned. In addition, 21
The compression spring 2 is inserted into the hole 22 formed in the movable mold 5.
When the movable core 12 moves to the right in conjunction with the mold opening operation as described later, the ball stored together with the ball 3 engages with the four hemispherical parts 24 on the bottom of the movable core 12. to hold the movable core 12 so that it does not shift.

Next, the operation of the above configuration will be explained. With the mold closed as shown in FIG. 1, molten plastic is injected into the cavity 6 through a gate (not shown). The injected molten plastic fills the cavity 6 and eventually solidifies to form the front spring /L/2. After molding, moveable mold 5
Move it downward to open the mold. Then, the front spring /I
/2 is attached to the movable mold 5 and moves downward to the fixed mold 4.
is extracted from the recess 4a. Therefore, the above-mentioned movable type 5
Due to the mold opening operation, the movable core 12 slides downward along the inclined pin 9, so that the movable core 12 moves to the right due to the inclination of the inclined pin 9. In this way, the movable core 12
When the movable core 18 moves to the right, the pin 19 of the movable core 18 slides relatively from the upper end to the lower end of the inclined guide groove 16 of the movable core 12. It moves in the direction of the arrow as if being pulled down, and the small diameter tip portion 18a comes out from the hole 7 of the front spring fv2 (see FIG. 2). Next, the front spring /L'2 is pushed up by an ejector pin (not shown) and removed from the movable mold 5. After this, the movable mold 5 moves upward to mold the flannel and closes the mold.The mold closing operation of the movable mold 5 causes the inclined pin 9 to
The movable core 12 that has been pulled out is again fitted into the inclined pin 9 through the inclined hole 13 and slid upward along the inclined pin 9. Therefore, the movable core 12 moves to the left due to the inclination of the inclined pin 9, and due to this leftward movement of the movable core 12,
The pin 19 of the movable core 18 comes to slide relatively toward the upper end portion of the guide groove 16. As a result, movable core 1
8 is pushed up by the movable core 12 and moves in the opposite direction of arrow A, and the small diameter portion 18a of the tip is moved into the cavity 6a.
invade inside. In this way, the mold 1 is brought into the closed state shown in FIG. 1, and in this state, molten plastic is injected into the ζ mold 6, and the next front panel is molded.

In the above embodiment, the inclined pin 9 is attached to the fixed mold 4,
Although the movable core 12 and the movable core 18 were provided in the movable mold 5,
Attach the tilt pin to the movable mold so that the movable mold moves independently while leaving the front panel on the fixed mold when the mold is opened.
The movable core and the movable core may be provided in a fixed manner.

In addition, the present invention is not limited to the embodiment described above and shown in the drawings, and the undercut portion may include not only the hole 7 as in the above embodiment but also the inclined recess 21 as shown in FIG. The invention can be implemented with various changes without departing from the gist, such as being applicable to the invention.

〔Effect of the invention〕

According to the present invention, the following excellent effects can be achieved.
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l/r LM ll+1+ 1 Since the movable core can be moved in the inclined direction, it is possible to undercut holes or four parts that are inclined with respect to the opening/closing direction of the mold without using a hydraulic cylinder. . Therefore, unlike in the past, there is no need to provide a dedicated pressure oil supply mechanism, and equipment costs can be reduced. In addition, since the movable core can be inserted into and extracted from the cavity simultaneously with the opening and closing operations of the mold, the time required for molding can be shortened and productivity can be improved.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the present invention, in which FIG. 1 is a partial vertical sectional view of the mold shown in the mold closed state, FIG. 2 is a view equivalent to FIG. 1 showing the mold in the open state, and FIG. FIG. 3 is an exploded perspective view of the main parts, and FIG. 4 is a perspective view showing another example of an object to which the present invention is applied. In the figure, 1 is a molding die, 2 is a front spring /I/ (plastic molded product), 4 is a fixed die (one die), 5 is a movable die (the other die), 7 is a hole, and 8 is an undercut treatment. device, 9 is a tilt pin, 12 is a movable core, 16 is a guide groove (guide portion), 1
8 is a movable core, 19 is a pin (engaging part), and 21 is four parts. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. In a mold for molding a plastic molded product having a hole or four parts that are inclined with respect to the opening and closing direction of the mold and are undercuts, an inclined pin attached to one mold and a pin attached to the other mold with respect to the opening and closing direction of the mold. a movable core that is provided to be movable in the lateral direction and that slides along the inclined pin and reciprocates in the lateral direction when a mold is opened and closed; a guide portion that is formed on the movable core and that inclines in a predetermined direction; The cavity is movably provided in the mold in the direction of inclination of the hole or the four parts, and has an engaging part that engages with the guide part, and is interlocked with the reciprocating movement of the movable core to form a cavity before molding of the plastic molded product. An undercut treatment device for plastic molds, comprising a movable core that enters the mold and is extracted from the hole or four parts after molding.