JPH0129059Y2 - - Google Patents

Description

[Detailed explanation of the idea] (b) Industrial application fields The present invention relates to an injection mold for synthetic resin, etc.

(b) Prior Art A slide core that slides perpendicular to the mold opening direction is used to form a portion on the side surface of a molded product that becomes an undercut in the mold opening direction. However, the undercut portion may also become an undercut in the sliding direction of the slide core. For example, this is the case when forming something like a desk drawer pull on the side of a molded product. An example of a mold that makes it possible to form such an undercut portion is disclosed in Japanese Utility Model Application Publication No. 57-201326, but this tends to have a slightly too complicated structure.

(c) Purpose of the invention The purpose of the invention is to simplify the overall configuration of a mold that forms an undercut not only in the mold opening direction but also in the sliding direction of the slide core.

(d) Structure of the invention In the invention, a movable plate that moves synchronously with the molded product projecting member is arranged on the surface of the moving unit. A first slide core that forms the front side of the side protrusion of the molded product is attached to the surface of the movable plate, and a second slide core that forms the back side of the side protrusion is attached to the main body of the movable unit. The second slide core is formed into an undercut shape in the sliding direction. This second slide core is biased by a spring in the direction of separation from the molded product, and its movement is controlled by a cam surface provided on the movable plate.

(E) Embodiment In the figure, 1 is a stationary unit, and 2 is a moving unit. The fixed side unit 1 has a structure in which a mounting plate 3, a runner stripper plate 4, and a cavity block 5 are stacked in sequence.
A sprue passage is provided through the mounting plate 3 and the runner stripper plate 4, leading to a runner passage 7 carved into the cavity block 5. The runner passage 7 is connected to a cavity 8 formed between the stationary block 1 and the movable block 2. 9 is a runner retaining pin that protrudes from the mounting plate 3 and is attached to the runner stripper plate 4.
The inverted conical tip is inserted into the runner passageway 7 through the runner. Reference numeral 10 is an elastic body (made of urethane rubber) fixed to the mounting plate 3, and exerts a resilient force on the cavity block 5 through the through hole of the runner stripper plate 4. A stopper bolt 11 connects the runner stripper plate 4 and the cavity lock 5, and is fixed to the runner stripper plate 4 with a nut 12. The nut 12 and the mounting plate 3, the bolt 11 and the cavity lock 5 are each slidable in the axial direction, and the flange 13 provided on the nut 12 and the head 14 of the bolt 11 limit their respective sliding distances. are doing. 15 is a runner stripper plate 4, a cavity block 5,
and a guide pin protruding from the mounting plate 3 to guide the movement of the moving block 2.

The mobile unit 2 is constructed as follows. 1
6 is a mounting plate to which a core block 18 is fixed via a connecting block 17, and a movable plate 19 is stacked in front of the core block 18. An ejector plate 20 is disposed in a space surrounded by the connecting block 17, and is provided with an ejector pin 21 for ejecting the molded product and a return pin 22 that receives a return force from the movable plate 19. A return bolt 23 is screwed into the movable plate 19 through the core block 18. A return spring 24 wound around the return bolt 23 always applies a force to the movable plate 19 to keep it in close contact with the core block 18. A first slide block 25 is mounted on the surface of the movable plate 19, and forms the front side of the side protrusion 27 of the molded product 26. The slide block 25 is moved by the finger pin 28 of the cavity block 5. 2
9 is a second unit attached to the main body side of the moving block 2.
A part of the slide core penetrates through the movable plate 19,
The side and end surfaces of the molded product 26 and the back side of the side protrusion 27 are molded. The back side of this side protrusion 27 forms an undercut with respect to the moving direction of the slide core 29. The slide core 29 is biased by a spring 30 in the direction of separating from the molded product 26. Movable plate 19
is provided with a cam surface 31 that contacts the slide core 29, thereby controlling the movement of the slide core 29.

The function of the above mold is as follows. First of all
Molten resin is injected and molded in the mold closed state shown in the figure. When the mold is opened after the resin has solidified, the adhesive force acting between it and the moving unit 2 causes the cavity block 5 to be pulled out as shown in FIG. The runner 32 remains behind, retained by the runner retaining pin 9, and is separated from the molded part 26. When the distance between the runner stripper plate 4 and the runner stripper plate 4 is sufficiently wide, the cavity lock 5 hits the head 14 of the stopper bolt 11 and gives an impact to the stopper bolt 11. Therefore, the stopper bolt 11 moves forward together with the runner stripper plate 4 by the amount of play between the nut 12 and the mounting plate 3, and applies a brake to the cavity lock 5.
The movement of the runner stripper plate 4 at this time causes the runner 32 to be peeled off from the runner retaining pin 9 and removed. The elastic body 10 serves to force the cavity block 5 to move forward together with the movable unit 2 by forcibly starting the movement by means of an elastic force. Cavity block 5
Even after the moving unit 2 has stopped, the moving unit 2 continues to move.
During this process, the slide core 25 is pushed open by the finger pins 28 at right angles to the mold opening direction, as shown in FIG. As shown in FIG. 4, the protruding rod 33 that was waiting in front of the moving unit 2 hits the ejector plate 20 and stops it, and the core block 18 continues to move. are pushed out relatively, and the ejector pin 21 and the movable plate 1
9, the molded product 26 is ejected. At this time, the slide core 29 is pushed outward by the movement of the cam surface 31. The molded product 26 itself is the slide core 2
Since it is moving away from 9, the slide core 29
molded product 2 without hitting the undercut.
You can leave from 6. When the mold is closed, the slide core 29 is pushed back inward by the cam surface 31.

(f) Effects of the invention A configuration in which a moving unit is provided with a movable plate that moves in synchronization with the protruding member and a slide core is attached to this movable plate is often seen. In this invention, the slide core attached to the movable plate is used for forming the front side of the side protrusion of the molded product, and the second slide core attached to the main body of the movable unit is used so as to be hidden behind the movable plate. , a part on the back side of the side protrusion of the molded product that becomes an undercut with respect to the direction of movement of the slide core is molded, and this second slide core is biased with a spring in the direction of separating from the molded product, and is movable. Since its movement is controlled by a cam surface provided on the plate, it is simple and robust, and has the advantage that there is no place where excessive force is applied.

[Brief explanation of drawings]

FIGS. 1 to 4 are cross-sectional views showing one embodiment of the present invention, and show a series of processes from molding to completion of mold opening. DESCRIPTION OF SYMBOLS 1... Fixed side unit, 2... Moving side unit, 26... Molded product, 27... Side protrusion, 19...
...Movable plate, 25...First slide core, 29...
...Second slide core, 30...Spring, 31...
cam surface.

Claims (1)

[Scope of Claim for Utility Model Registration] A stationary unit and a movable unit that cooperate to form a molded product; a movable plate disposed on the surface of the movable unit so as to move in synchronization with a molded product projecting member; A first slide core attached to the surface of the movable plate to form the front side of the side protrusion of the molded product, and a first slide core that slides in the same direction as the first slide core and has an undercut shape with respect to the sliding direction. a second slide core attached to the main body of the movable unit to be formed on the back side of the side protrusion of the molded product; a spring that urges the second slide core in a direction to separate from the molded product; and a cam surface provided on the movable plate to control movement of the second slide core.