JPS627457Y2 - - Google Patents

Description

[Detailed Description of the Invention] <<Field of the Invention>> This invention relates to an improvement of a mold for injection molding a product having a rolled-up portion on one side of the molded product.

<<Prior Art and its Problems>> Conventionally, a mold for injection molding this type of molded product has a mold design as shown in FIG. 1, for example.

This is a fixed side template 2 with a sprue 1 drilled in it.
and a movable template 4 which is removably engaged with the fixed template 2 and has a runner 3 formed on its parting surface with the fixed template; Together with the movable mold plate 4, it is composed of a core knot 6 which forms a product cavity 5 between it and the fixed mold plate 2, and the shape of the core knot 6 is such that it has an undercut portion on one side thereof. By projecting the core knot 6 from the movable mold plate 4 after injection molding, the molded product formed in the cavity 5 can be taken out.

Further, as for the shape of the gate connecting the runner 3 and the product cavity 5, as shown in FIG. A knockout pin 8 having a communication groove 8a is provided on the outer periphery of the mold surface of the movable mold plate 4 so that the resin injected from the sprue 1 and the runner 3 passes through the gate 7 at one end. It is in the lower part of the cavity and is injected and filled into the cavity 5 through the communication groove 8a.

The reason why the submarine gate 7 is used as a gate in this way is mainly to facilitate gate cutting.

However, such submarine gate 7
When the cavities 5 are connected by the communication groove 8a, for example, when the core knob 6 protrudes from the movable mold plate 4 and a molded product corresponding to the product cavity 5 is taken out, the molded product corresponding to the product cavity 5 is taken out. It is necessary to take out the molded product, but in this case, the communication groove 8a interferes with the product, making it difficult to take out. The resin filled inside must be removed in torn form, making demolding work extremely difficult.

In addition, the communication groove 8a that communicates with the molded product in this way
In the case where a groove 8a is formed, there is a problem that sink marks are likely to occur on the surface of the molded product facing the communication groove 8a.

<<Purpose of the invention>> The present invention was created in view of the problems in mold design as described above. It is an object of the present invention to provide a mold structure that can perform this automatically and also prevent the occurrence of sink marks on the product surface at the gate portion.

<<Structure and effects of the invention>> In order to achieve the above object, the injection molding mold according to the present invention is a mold for injection molding a product having a rolled part on one side of the molded product, and The mold is removably engaged with a fixed side template 11 in which a sprue 10 is bored, and a runner 15 and a product cavity 16 are formed on the parting surface with the fixed side template 11. Movable side template 1
2 and the movable template 12 formed in a shape corresponding to the rolled-up portion of the product cavity 16.
A core hole 17 is inserted through the movable side mold plate 12 and forms a product mold surface in cooperation with the mold plate 12, and a pin point 20a is inserted between the runner 15 and the cavity 16 on the outer periphery of the tip. A first ejector pin 18 having a spiral submarine gate 20 communicating therewith, and the movable side mold plate 1
The ejector mechanism includes a second ejector pin 19 that is inserted through the runner 2 and whose tip is in contact with the runner 15, and an ejector mechanism that drives the core knob 17 and the first and second ejector pins 18 and 19. A plurality of ejector plates that respectively drive the first and second ejector pins 18 and 19 are stacked on the retreating end side of the movable mold plate 12, and the base of the core knob 17 is fixed to this ejector plate. In addition, each ejector plate has a stopper flange 18 provided on the outer periphery of the first and second ejector pins 18 and 19.
spaces 27a and 27b are provided for accommodating the ejector pins 18 and 19a, and hold the ejector pins 18 and 19 so as to be movable by a predetermined stroke amount in the axial direction, and in conjunction with the separation movement of the movable mold plate 12. A piece 29 that rotates and separates the ejector plates from each other is provided, and when the movable mold plate 12 is separated, the core knob 17 protrudes and the product is separated from the movable mold plate 12.
Push up further and separate the gate resin between the pinpoint 20a, and then further move the movable template 12.
are separated, the first and second ejector pins 18 and 19 are projected by each ejector plate, and the sprue 10, runner 15, and gate resin are pushed up from the movable side mold plate 12, and then the subsequent movable side mold The piece 29 rotates due to the separation movement of the plate 12, and the second
The ejector plate that drives the ejector pin 19 is operated, and only the second ejector pin 19 is further pushed up to separate the gate resin from the first ejector pin 18.

That is, according to the above structure, in the first step, after injection molding, the core knot 17 is projected from the surface of the movable mold plate 12 due to the separation movement of the movable mold plate 12, and only the product is protruded from the mold surface. In the next stage, the movement of separating the movable template 12 further progresses, and the ejector plate moves the first and second ejector pins 18 and 19 to the movable template 12.
The gate resin and sprue 1 protrude from the mold surface.
0, the resin of the runner 15 is ejected in one piece, and finally, by further separating movement of the movable template 12,
The top 29 rotates and separates the respective ejector plates, pushing up only the ejector plates 21e and 22e that drive the second ejector pin 19, and the second ejector pin 19 further moves from the movable template 12 to the front side. The shape protrudes, and the gate resin is removed from the first ejector pin 18 and becomes ready to be discharged.

Therefore, in the present application, only the product can be separated from the mold surface and taken out, and then the sprue 10, runner 15 and gate resin are pushed up to perform a discharge operation, and the resin remaining in the submarine gate 20 is removed. Furthermore, since it is designed to be separated, the product can be taken out as a single product without having to manually cut the gate as in the past, and it also eliminates the parts where resin tends to accumulate inside the gate, such as the submarine gate 20. Since it can be mechanically undercut and discharged, it has the advantage that the product and the debris attached to the product can be automatically removed.

<<Description of Embodiment>> Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. 2 and subsequent drawings.

FIG. 2 shows an injection molding mold according to this invention, which includes a fixed side mold plate 11 in which a sprue 10 is bored, and which is removably engaged with the fixed side mold plate 11. The movable mold plate 12 is provided with a movable mounting plate 14 which is integrally connected to the movable mold plate 12 via a support 13 at the rear end of the movable mold plate 12.

Then, the fixed side template 11 and the movable side template 12
A runner 15 and a product cavity 16 are formed on the parting surface between the parts, and one end of the product cavity 16 is shaped to wrap around the lower surface of the movable template 12. It has an undercut shape.

A tapered core hole 17 is inserted into the movable template 12 corresponding to the undercut portion 16a, and when the fixed template 11 and the movable template 12 are engaged, the movable template 12 is inserted into the movable template 12. It cooperates with the template 12 to form a product mold surface.

In addition, a first ejector pin 18 is provided at the gate portion connecting the runner 15 and the product cavity 16.
is inserted through the runner 15 of the stationary side template.
A second ejector pin 19 is inserted through the surface facing the .

A submarine gate 20 is spirally carved on the outer periphery of the tip of the first ejector pin 18, and the submarine gate 20 connects one end to the runner 15 and the other end to the cavity 16. The cavity 16 of this gate 20
The joint portion with the wire is a pinpoint 20a.

The bases of the core knob 17 and the first and second ejector pins 18 and 19 are provided between the movable template 12 and the movable mounting plate 14, and are attached to a plurality of laminated ejector plates 21a to 24e. Further, the ejector plate 24e located at the rearmost end of these ejector plates is held by an ejector pin 25 provided through the movable side mounting plate 14.

That is, the base of the core knob 17 passes through the ejector plate 21e located at the most distal end, and is connected to the ejector plate 22e on the lower surface side by its flange 17b. Further, the first ejector pin 18 passes through each of the ejector plates 21e to 24e, and has its protruding end facing the movable side mounting plate 14, and the second ejector pin 18
The ejector plate 19 also passes through each ejector plate 21e to 24e and attaches to the movable side mounting plate 14.
It is located opposite.

A stopper flange 18a is formed on the rear outer periphery of the first ejector pin 18, and this flange 18a is accommodated in a cavity 27a formed in the ejector plates 23e and 24e. For each ejector plate 21e to 24e, the first
The ejector pin 18 is movable.

Further, a stopper flange 19 is provided on the rear outer periphery of the second ejector pin 19 and is fitted into a gap 27b formed in the ejector plates 21e and 22e.
a is formed, which also includes each ejector plate 21.
It is possible to freely move by a distance a in the traveling direction of e to 24e.

Further, a locking block 28 is formed on the inner side of the support, and a piece 29 that contacts the locking block 28 is provided to be able to contact and rotate the ejector plate 23e via a pin 30. It is being

The distance between the contact block 28 and the piece 29 is determined by the distance between the first and second ejector pins 1.
In addition to the free movement distance a of the ejector pins 8 and 19, this corresponds to the protrusion amount b of each ejector pin 18 and 19.

Therefore, from the state in which the fixed mold plate 11 and the movable mold plate 12 shown in FIG. When the movable side mold plate 12 is separated from the fixed side mold plate 11 after the resin has solidified, first, as the movable side mounting plate 14 is moved away, the core knot 1 is relatively
7 protrudes from the movable mold plate 12, thereby pushing the product formed within the cavity 16 above the mold surface (see FIG. 3a).

At this time, since the resin filled in the gate and the product are connected only through the pinpoint 20a, the protrusion of the core knob 17 easily disconnects the product and the pinpoint 20a.

Next, when the movable mounting plate 14 moves back by a distance a, the first and second ejector pins 18, 19
The rear end portion is stopped by a distance a, but as the movable mounting plate 14 moves back by the distance a, its flanges 18a and 19a now close to the respective air gaps 27.
a, 27b, thereby protruding from the surface of the movable mold plate (see FIG. 3b).

At this time, ejector plates 21e, 22e
serves to drive the second ejector pin 19, and the ejector plates 23e and 24e serve to drive the first ejector pin 18.

Note that the first and second ejector pins 18 and 19
The ejecting operation continues for a moving distance b, that is, at the stage when the first and second ejector pins 18 and 19 protrude from the surface of the movable mold plate 12 by a distance b, the piece 29 touches the end of the locking block 28. As the movable mounting plate 14 moves back from this state, the top 29 rotates about the pin 30, pushing up the ejector plates 21e and 22e, and this time the second ejector pin 19 will protrude further from the movable mold plate 12, and in this case, the gate resin remaining in a spiral shape on the outer circumference of the first ejector pin 18 will be removed as the second ejector pin 19 protrudes. the first ejector pin 1
The resin within the gate No. 8 will be removed (see FIG. 3c).

As the top 29 rotates, the ejector plates 21e and 22e that drive the second ejector pin 19 move by a distance c, and the second ejector pin 19 moves by the distance c. It will protrude further than the first ejector pin 18.

Therefore, when such a product removal operation is performed, only the product is ejected from the mold surface in the first step, and in the next step, the gate resin, sprue 10, and runner resin are ejected as one unit. is,
Then, the gate resin is removed from the first ejector pin 18 and becomes ready to be discharged.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged sectional view showing a conventional mold structure having a submarine gate, FIG. 2 is a partially enlarged sectional view showing the structure of an injection mold according to this invention,
FIGS. 3a to 3c are partially enlarged cross-sectional views for explaining the process of demolding the mold. 10...Sprue, 11...Fixed side template, 12...
...Movable side template, 15...Runner, 17...Core nut, 18...First ejector pin, 19...
Second ejector pin, 18a, 19a... stopper flange, 20... gate, 20a... pinpoint, 21e to 24e... ejector plate, 29... piece.

Claims (1)

[Claims for Utility Model Registration] A mold for injection molding a product having a rolled up part on one side of the molded product, the mold comprises a fixed side mold plate 11 in which a sprue 10 is bored, and The fixed side template 1 is removably engaged with the fixed side template 11, and the fixed side template 1
A movable mold plate 12 has a runner 15 and a product cavity 16 formed on the parting surface with the mold plate 1, and a movable mold plate 12 is formed in a shape corresponding to the winding part of the product cavity 16 and is inserted through the movable mold plate 12. A core hole 17 that cooperates with the mold plate 12 to form a product mold surface is inserted through the movable mold plate 12 and communicates between the runner 15 and the cavity 16 via pinpoints 20a on the outer periphery of its tip. A first ejector pin 18 with a spiral submarine gate 20 carved thereon, a second ejector pin 19 that is inserted through the movable side mold plate 12 and whose tip is in contact with the runner 15, and these core holes 17 and the first ejector pin 18. , second ejector pin 1
The ejector mechanism includes a plurality of ejector plates that drive the first and second ejector pins 18 and 19, respectively, stacked on the retreating end side of the movable mold plate 12. The base of the core knot 17 is fixed to this ejector plate, and each ejector plate has a stopper flange 18 provided on the outer periphery of the first and second ejector pins 18 and 19.
spaces 27a and 27b are provided for accommodating the ejector pins 18 and 19a, and hold the ejector pins 18 and 19 so as to be movable by a predetermined stroke amount in the axial direction, and in conjunction with the separation movement of the movable mold plate 12. A piece 29 that rotates and separates the ejector plates from each other is provided, and when the movable mold plate 12 is separated, the core knob 17 protrudes and the product is separated from the movable mold plate 12.
Push up further and separate the gate resin between the pinpoint 20a, and then further move the movable template 12.
are separated, the first and second ejector pins 18 and 19 are projected by each ejector plate, and the sprue 10, runner 15, and gate resin are pushed up from the movable side mold plate 12, and then the subsequent movable side mold The piece 29 rotates due to the separation movement of the plate 12, and the second
An injection molding mold characterized in that an ejector plate that drives an ejector pin 19 is operated to further push up only the second ejector pin 19 to separate the gate resin from the first ejector pin 18.