JPH0929787A - Gate valve mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gate valve mold capable of arbitrarily switching a gate without nedessity of a plurality of temperature controls for sealing a gate. SOLUTION: A gate switching valve is formed of a needle 20 vertically movably provided along a subrunner 19. The longitudinal retreating operations of ejector plates 12, 13 are transmitted to the needle 20 via linkage means 21 having a movable side operating rod 25, a stationary side operating rod 23 and a coupling member 22, and the end of the needle 20 is connected to or separated from a pin point gate 18 to switch the gate. A heater for sealing the gate is not necessarily provided at the end of a hot tip bushing 8, and its temperature control is eliminated as well. Since the needle 20 is driven by the plates 12, 13 irrespective of the manifold pressure, the switching timing of the gate can be entirely arbitrarily set.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an improvement of a gate valve mold.

[0002]

2. Description of the Related Art Insulated dies, hot runner dies, and the like are known as dies that employ a runner system for reducing resin waste generated in sprues and runners.

Insulated dies are formed by continuous injection molding while forming a heat-insulating layer by a resin layer which is in direct contact with the inner wall surface of the runner and is solidified by cooling to prevent the temperature drop and solidification of the resin in the center of the runner. In addition, the hot runner mold is designed to perform continuous injection molding work by securing the molten state of all the resin inside the runner by forcibly heating the manifold block that constitutes the runner part with a heater. Is to do.

In either case, since the fluidity of the resin inside the runner is high, the gate structure that can be used is generally limited to the pinpoint gate because of the necessity of the gate seal.

In particular, in the case of a hot runner die, the fluidity of the resin inside the runner is remarkably high, and therefore the gate seal may be incomplete if the gate structure is made to be a pinpoint gate, and the manifold block itself is forced. In addition to the heater for heating, a heater for controlling the temperature in the vicinity of the pinpoint gate to perform gate sealing is additionally required. In other words, from the start of injection to the completion of injection, the heater for the gate seal is heated together with the heater for the manifold to fill the resin into the mold cavity with the gate open, and then the heater for the gate seal is closed. Only heating is released and the surrounding resin is cooled and solidified to perform gate sealing. This heater for gate seal is a substantial gate opening / closing valve in the hot runner mold.

However, according to this method, it is necessary to control the heater for the manifold and the heater for the gate seal independently, and there is a drawback that the temperature control becomes complicated. Further, even if the heating of the heater for the gate seal is released, it takes a certain amount of time for the temperature of the resin around the pinpoint gate to drop and solidify, so that the gate seal cannot be performed immediately. . This means that after the injection is completed, the injection screw must be driven to apply the holding pressure from the injection cylinder side, which is a waste of power in some cases.

As a means for eliminating the troublesomeness of temperature control and enhancing the immediate effect of the gate seal, a mechanical gate opening / closing valve consisting of a needle for closing the pinpoint gate and a spring for urging the needle is known in the prior art. Has already been proposed as. To put it simply, the needle that closes the pinpoint gate is urged by a spring to rush into the pinpoint gate at all times, and the rise in pressure in the manifold during injection is used to resist the urging force of the spring. The needle is retracted, the gate is opened, and the injection operation is performed. However, as is apparent from this configuration, the actual injection operation cannot be started until the pressure inside the manifold exceeds the biasing force of the spring, and naturally the injection pressure gradually rises. It is not suitable for injection control at all, and if the pressure in the manifold falls below the urging force of the spring, the needle will automatically rush into the gate and complete the gate seal, so you can freely set the gate seal timing. You can't do that at all. Therefore, contrary to the above,
This is extremely disadvantageous in the case where the injection screw is driven after the injection is completed to adjust the holding pressure from the injection cylinder side.

As described above, the conventional gate opening / closing valve consisting only of the needle and the spring has an essential problem that the molding conditions are significantly restricted by its construction, and the substantial gate opening / closing valve. In the case of an insulated mold not equipped with, there is a drawback that the timing of gate sealing is completely up to the discretion.

As described above, depending on the type of the product to be molded, it may be possible to obtain better results by adjusting the holding pressure by pressing the injection screw without sealing the gate even after the injection is completed. Yes, in this case,
A large gate diameter is overwhelmingly advantageous from the perspective of screw pressure transmission, but there is also the problem that the gate seal becomes extremely difficult due to the expanded diameter of the gate.So far, insulated molds and hot runners have been used. It has been considered difficult to apply a pinpoint gate having a large diameter to a die.

When the reliability of resin filling and the pressure holding control are prioritized, the so-called direct gate mold, that is, the mold constituted by directly connecting the sprue to the mold cavity is the most suitable. It is advantageous. However, in the case of a direct gate mold, the sprue runner is taken out while being integrally connected to the back surface of the product body, and this sprue runner has to be cut by post-processing and thrown away, and the raw materials are wasted. The drawback is that
In addition, there is a drawback that the sprue runner is apt to cause haunting.

[0011]

Therefore, the object of the present invention is to solve the above-mentioned drawbacks of the prior art and to open / close the gate completely arbitrarily without requiring complicated temperature control for the gate seal. In addition, the injection operation can be performed by applying free molding conditions without restraining the molding conditions such as injection pressure, and the gate diameter can be freely set according to the type of product to be molded. It is an object of the present invention to provide a gate valve mold that can be designed and that can eliminate the troublesomeness of cutting off the runner by post-processing and waste of molding material.

[0012]

DISCLOSURE OF THE INVENTION The present invention is directed to a linkage means for transmitting a frontward / reverse movement of an ejector plate to a gate opening / closing valve, and a gate opening / closing valve for opening / closing a gate in response to a forward / backward movement of the ejector plate via the linkage means. The above-mentioned object is achieved by the constitution characterized in that

That is, by utilizing the frontward and backward movement of the ejector plate as the drive source of the gate opening / closing valve, it becomes unnecessary to dispose the heater for the gate seal and its temperature control, and the molding conditions are freely set and restrained. Without, that is, regardless of the resin pressure in the manifold, the gate can be freely opened and closed at any timing, and by completely closing the gate and automatically separating the product from the runner, The troublesomeness of the cutting work of the runner and the waste of the molding material due to the post-processing are eliminated (the above corresponds to claim 1).

In a more specific structure, the gate opening / closing valve itself has a structure for an insulated mold, a hot runner mold, etc. (including those using a pinpoint gate) and a direct gate mold. It is divided into a structure for molds (including a well type nozzle system, etc.).

First, a gate opening / closing valve for an insulated mold, a hot runner mold, or the like is provided in the fixed mold so as to be slidable in the mold clamping mold opening direction. The linkage means is composed of a needle protruding into the gate, and the linkage means is fixed to the ejector plate integrally, and is fixed to the movable side operation rod protruding through the movable side template slidably in the mold opening direction. A fixed side operation rod that is slidably provided in the side mold in the mold opening direction and engages with the tip of the movable side operation rod, and a coupling member that integrally connects the fixed side operation rod and the needle. It is composed of

That is, such as an insulated mold and a hot runner mold, the main runner provided in a plane orthogonal to the mold clamping mold opening direction in the fixed mold has a sub-runner in the mold clamping mold opening direction. In the configuration in which the main runner is extended and is connected to the pinpoint gate, a needle that directly moves in the mold closing mold opening direction inside the sub runner is provided so as to penetrate the main runner in the radial direction. The connecting member, fixed side operating rod,
The ejector plate is operated in the mold clamping mold opening direction via the linkage means composed of the movable side operation rod to open and close the gate by the needle (above,
(Corresponding to claim 2).

On the other hand, like a direct gate mold,
In the structure in which the sprue provided in the mold opening direction in the fixed mold is directly connected to the mold cavity,
The structure of the gate opening / closing valve as described above is not necessarily appropriate. No matter how long the needle provided along the axial direction of the sprue is extended, the end of the needle does not penetrate the runner system and protrude outside, which makes it difficult to operate the needle from outside the runner system. Is.

Therefore, in a structure such as a direct gate mold in which a sprue provided in the mold clamping mold opening direction in the fixed side mold is directly connected to the mold cavity,
A gate opening / closing valve is constructed by slidably installing a rod material that protrudes into the sprue in a sprue of a fixed side mold. In addition to the movable side operation rod and the fixed side operation rod as described above, the linkage means is further provided integrally with the fixed side operation rod so that the rod member is in a plane orthogonal to the mold clamping die opening direction. It is composed of a holding member that holds slidably.

That is, the holding member is operated in the mold clamping die opening direction by the ejector plate via the fixed side operating rod and the movable side operating rod to allow movement of the rod material in a plane orthogonal to the mold clamping die opening direction. At the same time, the rod material is obliquely crossed to the sprue to enter or retract to open and close the gate made of the sprue runner (the above corresponds to claim 3).

In the structure in which the gate is opened and closed by slidably interlocking the rod material with the sprue of the stationary mold, the amount of movement of the rod material required to open and close the gate (the mold clamping mold opening direction) The amount of movement in the plane orthogonal to is proportional to the inner diameter of the sprue. It is of course possible to open and close the gate with only one rod material, but it is recommended that the rod material be inserted from both sides in the radial direction of the sprue and the tips of the rod materials abut each other to close the gate. For example, the moving amount of the rod material, that is, the moving amount of the ejector plate that is required to open and close the gate, will be half, and the moving stroke of the ejector and product release operation by the ejector pin will Considering the combination, it is very convenient.

To achieve this, the rod member, the movable side operating rod, the fixed side operating rod, and the holding member are symmetrically arranged with respect to the center axis of the sprue.
Corresponding to).

Further, since the movable side operation rod and the fixed side operation rod are always connected, the mold opening operation is impossible, while the movable side operation rod and the fixed side operation rod are always separated. Then, although the movable side operation rod can press the fixed side operation rod to open the gate, the movable side operation rod cannot pull the fixed side operation rod to perform the gate closing operation.

Therefore, between the movable side operating rod and the fixed side operating rod, there is provided a concave-convex fitting means which can be brought into and out of contact only when the ejector plate is at the retreat completion position, and the movable side operating rod in the mold closed state is used. While the pressing and pulling motions of the fixed side operating rod are ensured, the movable side operating rod and the fixed side operating rod can be separated, that is, the mold can be opened (the above corresponds to claim 5). .

The closing operation of the gate does not necessarily depend on the pulling of the fixed operation rod by the movable operation rod, but may be achieved by the automatic return operation of the fixed operation rod when the movable operation rod retracts. That is,
A return spring for urging the fixed operation rod toward the mold opening direction is provided in the fixed mold (above,
(Corresponding to claim 6).

Whether or not the product take-out work after the completion of molding is performed by the ejector pin of the movable mold depends on the kind of the product, but the product take-out work is performed by the ejector pin implanted in the ejector plate. In any case, there is no inconvenience to the present invention in which the ejector plate is used as the drive source for opening and closing the gate. In other words, when it is necessary to perform product release work with the ejector pins implanted in the ejector plate, a differential mechanism that prohibits the ejector pin projecting motion until the ejector plate advance amount reaches a predetermined amount is used. It suffices if it is provided on the plate side and the opening / closing operation of the gate and the ejecting operation of the ejector pin are independently performed (the above corresponds to claim 7).

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings. Figure 1 shows a hot runner mold 1
FIG. 11 is a cross-sectional view showing a specific example in the case where the present invention is applied to a state in which the gate is closed in a portion on the right side of the center line L1 and the gate is opened in a portion on the left side of the center line L1. It shows the broken state.

Among the constituent elements of the hot runner die 1, the construction of general functional parts required for normal molding operation is already well known to those skilled in the art, and therefore the correspondence between the reference numerals and the drawings is clarified. However, the detailed description will be omitted.

In short, 2 is a fixed side mounting plate, 3 is a fixed side back plate, 4 is a fixed side template, 5 is a locate ring, 6 is a sprue, 7 is a manifold block equipped with a heater for forced heating, and 8 is Similarly, a hot tip bushing equipped with a heater for forced heating (above, fixed side mold), 9 is a movable side mold plate, 10 is a spacer block, 11
Is a movable side mounting plate, 12 and 13 are ejector plates, 1
4 is an ejector pin (above, movable side metal mold).

Reference numeral 15 is an ejector rod provided on the moving platen of the injection molding machine, which is inserted into the hot runner die 1 through a through hole formed in the center of the movable side mounting plate 11 to eject the ejector plate. The movable plates 12 and 13 are moved forward from the movable side mounting plate 11 toward the movable side mold plate 9, or the ejector plates 12 and 13 are moved backward from the movable side mold plate 9 toward the movable side mount plate 11. . Of course, the movable side mold plate 9 and the ejector plates 12 and 1
There is also a structure in which a coil spring or the like is interposed between the ejector plates 12 and 13 and the ejector plates 12 and 13 are returned to their original positions, but here, the ejector rod 15 is directly fixed to the ejector plates 12 and 13. It shows that the ejector plates 12 and 13 are moved backward. The separate construction of the ejector plates 12 and 13 is a necessary measure for implanting the ejector pin 14 with a collar, and needless to say, the ejector pin 14 and the like after the implanting is completed. Both of the plates 12 and 13 are integrally fixed by bolts or the like, and they move integrally.

Conventionally, a gate seal heater, which is independent of the heater for forced heating of the manifold block 7 and the hot tip bushing 8, is provided at the tip of the hot tip bushing 8 to open and close the gate. However, of course, the hot chip in this embodiment
The bushing 8 is not provided with a heater for gate seal. Further, because the ejector pin 14 needs to form a differential mechanism, the ejector pin 14 is attached to the ejector plates 12 and 13 in a slightly different manner from the conventional one, but this point will be described later. I will decide.

Except for the above points, as far as the structure of general functional parts required for normal molding work is concerned, the hot runner die 1 in this embodiment is not particularly different from the conventional hot runner die. Absent.

That is, the runner system of this hot runner die 1 is similar to the conventional hot runner die in that the sprue runner 16 provided in the die closing direction in the fixed side die and the die opening direction. And a sub-runner 19 extending from the main runner 17 in the mold clamping mold opening direction and connected to the pinpoint gate 18 with respect to the structure of the gate opening / closing valve. Can have the structure described in claim 2.

What is important here is that in the hot runner die 1, the sub runner 19 is formed in the radial direction of the main runner 17. This allows the sub runner 19 to pass through the main runner 17 in the radial direction.
The needle 20 is provided inside, and the upper end portion of the needle 20 is projected from the upper surface of the manifold block 7, and this portion is operated in the mold clamping mold opening direction by the linkage means described later to open and close the pinpoint gate 18. It can be done arbitrarily.

In the example shown in FIG. 1, the tip portion of the needle 20 constituting the gate opening / closing valve is formed in a taper shape so as to be in close contact with the tip of the hot tip bushing 8, and the overall shape of the needle 20 is a cylindrical body. It is slidably fitted in a through hole formed in the upper surface of the manifold block 7 and prevents accidental resin leakage.

A connecting member 22 forming a part of the linkage means 21 is integrally fixed to the end of the needle 20, and a fixed side operating rod 23 is integrally fixed to the connecting member 22. There is. Like the ejector plates 12 and 13 described above, the coupling member 22 has a structure in which two plates are superposed and fixed, and the needle 2 is provided with a flange at the end.
The method of attaching the 0 and fixed side operation rods 23 to the connecting member 22 is substantially the same as the method of attaching the ejector pins 14 to the ejector plates 12 and 13. However, the needle 20 and the fixed-side operation rod 23 are attached to the connecting member 22 such that they cannot move in the axial direction at all with respect to the connecting member 22. The needle 20 and the fixed side operation rod 23 are completely parallel to each other, and the fixed side operation rod 23 is movable in the mold clamping mold opening direction with respect to the fixed side mold.

A return spring 2 formed of a coil spring is provided between the coupling member 22 and the fixed side mounting plate 2.
4, the fixed-side operation rod 23 is constantly urged in the mold opening direction, that is, in the direction in which the pinpoint gate 18 is closed. This is an embodiment of the configuration shown in claim 6.

As shown in FIG. 1, the movable operation rod 25 is integrally fixed to the ejector plates 12 and 13, and is provided so as to slidably penetrate the movable mold plate 9 in the mold clamping mold opening direction, and its tip end. Engages with the fixed side operation rod 23. This fixed side operation rod 23 is also not able to move in the axial direction with respect to the ejector plates 12 and 13.

Even with the above-described structure alone, the ejector rod 15 is projected and the fixed side operation rod 23 is pushed up against the elastic force of the return spring 24 to pull up the needle 20 and open the pinpoint gate 18. , And the ejector plates 12 and 13 and the movable side operating rod 25 are pulled back, and the elastic force of the return spring 24 causes the fixed side operating rod 23, the coupling member 22 and the needle 20 integral therewith to move to their original positions. It is possible to return and close the pinpoint gate 18.

However, with such a structure, unless the elastic force of the return spring 24 is made strong, the sliding resistance of the fixed side operation rod 23 and the needle 20 cannot be overcome and the original position cannot be restored. On the other hand, when the pinpoint gate 18 is opened, it is necessary to overcome the elastic force of the return spring 24 and push the ejector plates 12 and 13 forward, so that the driving force of the ejector rod 15 must be increased.

Therefore, in the present embodiment, further, between the movable side operating rod 25 and the fixed side operating rod 23,
When the ejector plates 12 and 13 are at the retreat completion position, a concave and convex fitting means that can be brought into and out of contact with each other is provided, and when the pinpoint gate 18 is closed, this concave and convex fitting means does not rely only on the elastic force of the return spring 24. The fixed side operation rod 23 is pulled back by the movable side operation rod 25 via the. This is a specific embodiment of the configuration shown in claim 5.

The concavo-convex fitting means comprises a barrel-shaped plug 26 fixed to the tip of the movable operation rod 25 and a jack 27 fixed to the tip of the fixed operation rod 23. The jack 27 is formed of a pipe body whose inner peripheral surface is reduced in diameter. The diameter of the tip reduced diameter portion is slightly smaller than the maximum outer diameter of the barrel-shaped plug 26, and the diameter reduction is performed. A plurality of through-grooves are provided in the thick portion of the portion along the axial direction, and the axial center of the jack 27 is aligned with the plug 26.
When the tip of the plug is pushed in, the diameter reduction portion of the jack 27 is expanded due to the wedge effect of the plug 26 and the elastic deformation of the tip of the jack 27, so that the plug 26 can be housed in the jack 27. This through groove is, for example, like a pin vise chuck structure. In short, the through groove at the tip of the jack 27 divides the tip portion of the jack 27 into a plurality of portions in the circumferential direction. Each of them is curved like a cantilever whose one end is supported away from the axial center of the jack 27, thereby expanding the inner diameter of the tip portion. Further, in order to allow the diameter expanding operation, a conical escape processing surface 28 is provided as a reamer at the opening of the through hole 29 formed in the fixed-side mold plate 4 for passing the fixed-side operation rod 23. Etc. are processed.

In the state shown on the right side of the center line L1 in FIG. 1, that is, the ejector plate 12,
13 is at the backward completion position and the fixed side operation rod 2
If 3 is returned to the original position, the moving platen of the injection molding machine is moved with the ejector plates 12 and 13 held at the retreat completion position to move the movable side mold away from the fixed side mold and the jack 27. And plug 26
The movable side operation rod 25 and the fixed side operation rod 23 can be separated from each other by releasing the engagement with. A barrel-shaped plug 2 when the plug 26 is pulled out from the jack 27.
This is because the tip end of the jack 27 is expanded by the wedge effect of 6, and the escape processing surface 28 allows this expansion operation.
Further, by moving the moving platen of the injection molding machine in the same state and pressing the movable mold against the fixed mold, the plug 26 can be joined to the jack 27 in the same manner. At this time, since the fixed side operation rod 23 is held at the original position by the elastic force of the return spring 24, even if the plug 26 collides with the jack 27, the fixed side operation rod 2 is held.
3 itself is not pushed in the mold closing direction, the fixed side operation rod 23 is held at its original position as it is, the tip of the jack 27 is expanded by the wedge effect of the beer barrel-shaped plug 26, and at the same time, this expansion operation is performed. This is because it is allowed by the escape processing surface 28. If the maximum outer diameter portion of the plug 26 penetrates beyond the minimum diameter portion of the jack 27, the jack 27
The tip of the rod returns to its original shape again due to its elastic force, and its entire shape returns to a straight pipe shape.

The fixed operation rod 23 and the connecting member 2
2. Kinetic energy transmitted from the movable side operation rod 25 to the fixed side operation rod 23 when the plug 26 strikes the jack 27 due to the inertial mass of the needle 20 and the frictional resistance between these members and the sliding surface. In some cases, the return spring 24 is not necessarily a necessary means for holding the fixed-side operation rod 23 in its original position.

On the other hand, when the movable side mold is pressed against the fixed side mold and the ejector rod 15 is projected and the movable side operation rod 25 is moved forward with the plug 26 and the jack 27 joined together, the fixed side operation rod is moved. The outer peripheral portion of the front end surface of the jack 27 fixed to the terminal 23 is pressed by the outer peripheral portion of the front end surface of the movable side operation rod 25, the fixed side operation rod 23 moves in the mold closing direction, and the needle 20 causes the pinpoint gate 18 to move. And the pinpoint gate 18 is opened. This is the state shown on the left side of the center line L1 in FIG.

Further, from this state, the ejector rod 1
When 5 is retracted and the movable side operation rod 25 is retracted,
The plug 26 fixed to the movable operation rod 25 pulls the jack 27 fixed to the fixed operation rod 23. Since the plug 26 has a beer barrel shape having a tapered outer peripheral surface whose diameter is reduced in both directions from its maximum outer diameter portion, naturally, even when the plug 26 is moved in the direction in which it is pulled out from the jack 27. A force to expand the diameter of the tip portion of the jack 27 acts, but in this case, since the outer peripheral surface of the jig 27 is constrained by the inner peripheral surface of the through hole 29 provided in the fixed-side mold plate 4, The diameter of the tip of the jack 27 is increased, that is, the plug 26 cannot be detached from the jack 27, and as a result, the fixed-side operation rod 23 is movable via the uneven fitting means formed of the plug 26 and the jack 27. The fixed side operation rod 23 is pulled by the side operation rod 25, moves in the mold opening direction, and the needle 20 closes the pinpoint gate 18.

Since the through hole 29 has a restraining action as described above, the tip of the jack 27 is actually expanded in the process of pulling back the fixed operating rod 23 so that the plug 26 can be expanded.
Although it does not come off at all, in the process of moving in the pullback direction, a force in the diameter expanding direction always acts on the tip portion of the jack 27, and the tip portion of the jack 27 is applied to the inner peripheral surface of the hole 29 with a considerably strong force. It is true that it is crimped, and the hole 29
It cannot be said that a galling between the inner peripheral surface of the jack and the jack 27 or an excessive sliding resistance may cause a problem. However, regarding this point, the above-mentioned return spring 24
It can be solved sufficiently by adding Most preferably,
The magnitude of the pulling force (effective element) transmitted from the movable side operating rod 25 to the fixed side operating rod 23 by the concave-convex fitting means and the accompanying increase in the sliding resistance of the jack 27 (inconvenient element), and , Return spring 2
The elastic force of No. 4 and the inconvenience of the strengthening of the drive source of the ejector rod 15 which is required therewith are well taken into consideration, and the force to be obtained by the concave and convex fitting means and the force to be obtained by the return spring 24 are appropriate. The design is such that the combination of the two forces works most effectively and no inconvenience occurs.

Further, the ejector pin 14 is attached to the same ejector plates 12 and 13 to which the movable operation rod 25 is fixed.
If a molded product is to be released from the movable-side mold by implanting the ejector rod 15 and projecting the ejector rod 15,
A differential mechanism is required to drive the ejector pin 14. However, in the case of molding an exterior product that is extremely sensitive to scratches, there is a case where the molded product is manually ejected after completion of the shape opening without using a means such as an ejector pin. , Ejector plate 12,
13 only functions as a means for attaching the movable side operation rod 25.

The mounting method of the ejector pins 14 on the ejector plates 12 and 13 is different from the conventional one. First, the support pins 31 having the same shape as the ejector pins 14 and a short dimension make the collar portions back to back. It is provided integrally with the ejector pin 14, a through hole is formed on the ejector plate 12 side for penetrating the pin portion of the support pin 31, and the collar portion of the ejector pin 14 is attached to the ejector plate 13. The length X of the large-diameter portion of the stepped through-hole 30 is formed longer than the combined thickness of the flange portions of the ejector pin 14 and the support pin 31. In addition, ejector pin 1
4 and the support pin 31 are formed separately from each other only in consideration of the ease of processing, and there is no problem even if these are completely integrated cut-out members.

The support pin 31 is attached to the entire length of the ejector pin 14.
1 is equal to the distance from the surface of the movable side mounting plate 11 to the parting line of the mold, and the ejector plates 12 and 13 are completely retracted as shown on the right side of the center line L1 in FIG. The upper surface of the collar portion of the ejector pin 14 is located at the position
The edge of the stepped through hole 30 of FIG.
However, in reality, it is possible to push the ejector pin 14 back to the retreat completion position by the resin pressure at the time of injection, so even if the large diameter portion of the stepped through hole 30 is machined a little deeper, there is a practical problem. There is no.

Since the length X of the large-diameter portion of the stepped through hole 30 is designed to be longer than the combined thickness of the flange portions of the ejector pin 14 and the support pin 31, the ejector plates 12 and 13 are In the state where the retreat is completed, there is a gap between the lower surface of the flange of the support pin 31 and the surface of the ejector plate 12, and injection work or the like is performed in this state. Since it is supported by the movable side mounting plate 11 via the, the ejector pin 14 does not retreat beyond the retraction completion position due to injection pressure or the like.

Then, when the ejector rod 15 is gradually projected from the state shown on the right side of the center line L1 in FIG.
The movable side operation rod 25 fixedly fixed to the above moves forward. However, since there is a gap between the lower surface of the collar portion of the support pin 31 and the surface of the ejector plate 12, the ejector pin 14 itself does not protrude unless the ejector rod 15 protrudes more than the gap. As shown on the left side of the center line L1 in FIG. 1, the limit for moving the movable side operating rod 25 without projecting the ejector pin 14 is a distance corresponding to the above-mentioned gap.

That is, within this range, it is possible to freely perform the forward retreating operation of only the movable operating rod 25 without operating the ejector pin 14, that is, the opening / closing operation of the pinpoint gate 18. The timing may be any time as long as the mold is closed from the completion of mold closing to the start of mold opening, there is no need to wait for the manifold pressure to rise as in the conventional mechanical gate opening / closing valve, and the manifold pressure The gate will not be closed without permission due to the decrease of the. Also, unlike the case where a heater for opening and closing the gate is provided at the tip of the hot tip bushing 8, the gate is not sealed by utilizing the solidification of the resin due to the temperature decrease, and the tip of the needle 20 is directly pinned by a mechanical structure. Since the point gate 18 is made to rush into the point gate to close the gate, there is no delay in waiting for a temperature change, and the gate cross-sectional area does not matter.

This is a differential mechanism of the ejector pin 14, which is a specific embodiment of the structure described in claim 7.

Then, the mold is opened and the ejector pin 14 is opened.
In the case of releasing the product by the projecting operation, the ejector rod 15 is further projected from the state shown on the left side of the center line L1 in FIG. 1, and the collar of the support pin 31 is formed on the surface of the ejector plate 12. The lower surface of the part is pushed up and the ejector pin 14 is projected from the parting line of the movable side mold to release the product. The support pin 31 itself is not fixed to the movable side mounting plate 11 and is separated from the movable side mounting plate 11 together with the ejector plates 12 and 13.

In addition, since the tip of the needle 20 is pressed against the pinpoint gate 18 by the elastic force of the return spring 24 when the mold is opened, there is absolutely no chance of inadvertent dripping from the gate 18. In addition, since the gate sealing function of the needle 20 also serves as a substantial gate cutting work, thread pulling prevention and post-processing of the gate cut surface of the product are automatically performed.

The gate opening / closing valve of the hot runner die 1 has been described above as an example. However, in the case of the insulated die, the manifold block 7 and the hot tip bushing 8 and the forced heating heater for them are eliminated. Except for the fact that the runners of each part are slightly thicker, the structure of the mold is exactly the same, and the gate opening / closing valve and linkage means of the above example can be applied as they are. Note that FIG. 2 shows an insulated mold 32 as an example thereof, and the respective portions are simply given the reference numerals corresponding to the above-described configuration example. Further, the structure of a normal sleep rate mold having a pinpoint gate is similar to that of the example of FIG. 2, in short, from a main runner and a main runner provided in a plane orthogonal to the mold opening direction. The above-mentioned needle 20 can be arranged as long as the mold is provided with a sub-runner that extends in the mold opening direction and connects to the pinpoint gate, and the gate opening / closing valve and the linkage means of the above example can be provided for all of them. Can be applied as is.

However, the problem here is the direct gate mold, that is, the mold constituted by directly connecting the sprue to the mold cavity. In the case of such a mold, if the above configuration is applied as it is, there is no other way than to arrange a needle in the sprue. Needless to say, in theory, the sprue runner as a whole is formed straight, the opening on the outlet side is squeezed, and the needle is placed in the sprue. The object can be achieved by taking out the operating rod which is installed and protruding in the radial direction of the needle and operating the operating rod in the vertical direction by the linkage means as described above. Of course,
In such a configuration, the flow of resin is blocked by the needle itself, so it is necessary to engrave an axial through groove or the like on the outer peripheral portion of the needle. However, a more serious problem is countermeasures against resin leakage. In the above example, since the resin is sealed by fitting the cylindrical needle 20 and the round hole on the upper surface of the manifold block 7, there is no particular problem, but the resin leakage between the long hole and the operating rod is prevented. Is technically difficult and not easy to implement. Further, in such a configuration, since the surge pressure of the resin directly acts on the needle located in the sprue, the strength of the needle and a member supporting the needle becomes a problem, and further, the resin flow is unnaturally deflected, which causes molding. The condition may deteriorate.

Therefore, for the direct gate mold, another embodiment as shown in FIG. 3 is further proposed.

FIG. 3 is a sectional view showing a specific example of the case where the present invention is applied to the direct gate die 33. Of these, the state in which the gate is opened in FIG.
FIG. 3B shows a state in which the gate is closed.
In FIG. 3C, a cross section taken along the line AA of FIG. 3B is taken out and shown. 3A shows the left half part of the direct gate mold 33, and FIG. 3B shows the right half part of the direct gate mold 33.
Each center line L2 is common.

Of the constituent elements of the direct gate die 33, the construction of general functional parts required for ordinary molding work is already known to those skilled in the art, and therefore, FIG.
In the above, only the correspondence between the reference numerals and the drawings will be clarified, and the detailed description will be omitted.

In short, 34 is a fixed side mounting plate, 35 is a fixed side mold plate, 36 is a locate ring, 37 is a sprue (above, fixed side mold), 38 is a movable side mold plate, 39 is a spacer block, 40 is 40 Movable side attachment plates, 41 and 42 are ejector plates, 43 is an ejector pin (above, movable side mold), and 44 is an ejector rod provided on the moving platen of the injection molding machine.

Further, in this embodiment, the linkage means 2 shown in FIG. 1 as a part of the linkage means 54.
The structure of 1 is used as it is, and the fixed side operation rod 4
5, return spring 46, movable side operation rod 47,
Regarding the configuration of the plug 48, the jack 49, the escape processing surface 50, the through hole 51, the stepped through hole 52, and the support pin 53, the fixed side operation rod 23, the return spring 24, the movable side operation rod 25 in the example of FIG. The plug 26, the jack 27, the escape processing surface 28, the through hole 29, the stepped through hole 30, and the support pin 31 are exactly the same.

The direct gate mold 33 in this embodiment is most different from the hot runner mold 1 of FIG. 1 and the insulated mold 32 of FIG. 2 in that the sprue 37 is directly connected to the mold cavity. Since the runner system is configured only by the sprue runner, as a result, the direct gate mold 33 does not have the main runner 17, the sub runner 19, or the equivalent thereof as shown in FIG. As a result, for the reasons already described, the deployment of the needle 20 as shown in the example of FIG. 1 becomes very difficult.

Therefore, in the present embodiment, the outer surface of the sprue 37 and the fixed side template 3 are obliquely intersected with the sprue 37.
5. A sprue 3 is formed by forming a circular through hole 55 that penetrates a part of the sprue 3.
The rod member 56 is slidably inserted in a slanted manner to 7 so as to close the sprue runner. This rod member 56 is the gate opening / closing valve in this embodiment. The cross-sectional shape of the through hole 55 and the rod member 56 is rounded in consideration of easiness of rubbing, that is, prevention of resin leakage, so long as machining accuracy is sufficiently achieved. Other shapes such as a rectangle may be used. In addition, when the two rod members 56 are thrust into the sprue 37 and abutted against each other, the tip end portions of the two rod members 56 are ground into a flat shape so that the abutting surfaces thereof are completely adhered. Has been issued. Needless to say, the outer diameter of the rod material 56 is 3 sprue.
It is larger than the inner diameter of 7.

Various members related to the rod member 56 and the linkage means 54 for moving the rod member 56 in the axial direction, that is, the rod member 56, the movable side operating rod 47, the fixed side operating rod 45, and the holding member 57 (detailed description). Each of the configurations will be described later) is symmetrically arranged laterally with respect to the central axis of the sprue 37 as shown in FIG. 3 (a) or FIG. 3 (b).

In the case of the example of FIG. 1, it is sufficient to simply move the needle 20 in the vertical direction, so the needle 20 should be integrally fixed to the connecting member 22, but in the case of this embodiment, the fixed side is fixed. Since the vertical movement of the operating rod 45 must be converted into an oblique movement to cause the rod material 56 to perform an oblique movement, the rod material 56 is clamped to the holding member 57 that connects the rod material 56 and the fixed side operating rod 45. It is required to have a function of slidably holding in a plane orthogonal to the mold opening direction.

As shown in FIGS. 3 (b) and 3 (c),
The holding member 57 has a structure in which an upper plate 57a and a lower plate 57b are integrally fixed by bolts or the like, and a slit 58 having a width for loosely fitting the rod portion of the rod member 56 is provided on the lower plate 57b side. Further, a rectangular groove 59 which is slightly wider than the slit 58 and which is loosely fitted in the flange portion of the rod member 56 is formed on the upper surface of the lower plate 57b so as to overlap with the slit 58. Slit 5
8B and the rectangular groove 59 are in the horizontal direction of the paper surface in FIG. 3B and in the thickness direction of the paper surface in FIG. 3C, and the rod member 56 has its flange portion fitted in the rectangular groove 59. The rod portion is attached so as to protrude downward from the slit 58 and be sandwiched between the upper plate 57a and the lower plate 57b.

That is, the rod member 56 is movable only in the horizontal direction with respect to the holding member 57 in FIG. 3B and in the thickness direction of the paper in FIG. Not acceptable at all. The holding member 57 itself is integrally attached to the fixed-side operation rod 45.

As described above, the state shown in FIG. 3 (b) is the position where the ejector plates 41, 42 have been completely retracted.
Therefore, when the ejector rod 44 is projected and the ejector plates 41 and 42 are pressed to move the movable side operation rod 47 and the fixed side operation rod 45 forward, the rod 4 is moved.
The holding member 57 fixed to 5 moves upward in the drawing, and a force for pulling up the rod member 56 acts. However, since the sliding direction of the rod member 56 is regulated by the through hole 55, the rod member 56 does not move upward in parallel as it is, and the rod member 56 that receives the axial component force of the pulling force is It moves diagonally upward along the axis of the through hole 55, the flanges of the rod members 56 are spaced outward from the central axis of the sprue 37, and the slit 58 and the rectangular groove of the lower plate 57b constituting the holding member 57 are formed. 59 and rod material 5
A slip occurs in the plane perpendicular to the opening direction of the mold clamping die. That is, as shown in FIG. 3A, the tips of the rod members 56 are separated from each other, the resin path of the sprue runner is opened, and the gate is opened.

Further, in this state, the ejector rod 44
When the holding member 57 is retracted by pulling back, the completely opposite phenomenon occurs, and the two rod members 57 approach each other to close the resin path of the sprue runner, as shown in FIG. 3 (b). The gate will be closed in such a state. The movable side operating rods 47 of the linkage means 54 for driving the respective rod members 56 are the same ejector plate 41,
Since it is integrally fixed to 42, the two rod members 5
7 synchronous operation is guaranteed. In addition, the stepped through holes 52,
As for the differential mechanism of the ejector pin 43 composed of the support pins 53 and the like, the same one as in the example of FIG. 1 is adopted, so that it is possible to only open and close the gate without operating the ejector pin 43. The opening / closing timing can be set to be completely arbitrary.

What has been described above is an example of embodying the configurations described in claims 3 and 4. This configuration,
This is especially effective for mold configurations in which it is difficult to attach the needle because the sprue is directly connected to the mold cavity. Of course, in addition to direct gate molds, well type nozzle type molds are also available. It is also available for etc.

Of course, it is possible to dispose the rod member 56 and the linkage means 54 for moving the rod member 56 in the axial direction only on one side to open / close the gate.
In that case, the ejector plate 4 in a state where the axial movement amount of one rod member 56 required for opening and closing the gate, that is, the movement of the ejector pin 43 is finally regulated.
The amount of forward retraction of 1, 42 will increase, and as a result,
There may be a problem that the substantial protrusion stroke of the ejector pin 43 has to be reduced.

Further, it is an inevitable structural result that the rod member 56 obliquely rushes into the sprue 37 at a position near the outlet side opening of the sprue 37, but it is more than necessary on the product side. In order not to make the post-processing troublesome by leaving the runner part of No. 2 and to not waste the material,
As shown in (b), it is desirable that the tips of the two rod members 56 abut against each other in the vicinity of the opening on the outlet side of the sprue 37.

[0074]

In the gate valve mold of the present invention, the gate opening / closing valve having a mechanical structure is operated by the forward / backward movement of the ejector plate to open / close the gate. Even in the case of an insulated mold or a hot runner mold in which injection molding work is continuously performed while ensuring fluidity, it is not necessary to provide a heater dedicated to the gate seal to perform the gate seal work. That is, it is only necessary to control the temperature of the manifold block and the main body of the hot tip bushing, and it is possible to reduce the number of heaters and simplify the processing for temperature control.

Further, instead of lowering the resin temperature around the gate to perform the gate sealing, the mechanical gate opening / closing valve directly closes the pinpoint gate.
The gate can be sealed immediately without waiting for the resin temperature around the gate to drop.

Further, since the gate opening / closing valve is driven by the forward / backward movement of the ejector plate, unlike the conventionally known mechanical gate opening / closing valve using a simple combination of the needle and the spring, the manifold The gate opening / closing timing can be set at will regardless of whether the pressure increases or decreases.

Further, the ejector plate to which the linkage means for driving the gate opening / closing valve is attached is provided with an operating mechanism for prohibiting the ejecting motion of the ejector pin and allowing only the ejector plate to retreat forward within a predetermined range. Even when the ejector pin is mounted on the ejector plate, only the gate opening / closing valve can be freely operated without the ejecting operation of the ejector pin. As a result, it is possible to open and close the gate at completely arbitrary timing as long as the mold is closed, and if you want to seal the gate early after completion of injection and keep the holding pressure at the time of injection completion as it is. The opening / closing operation of the gate can be set in response to various requests, such as when the gate is opened and the holding pressure is changed in time series by the pressing operation of the screw even after the injection is completed.

Moreover, unlike the conventional gate valve mold in which the resin temperature around the pinpoint gate is controlled to perform the gate sealing, the time required for the gate sealing is increased and the gate sealing time is extended even if the gate cross section is increased. There is no concern about dripping from the nose or stringing, and even with a pinpoint gate type mold, the gate cross-sectional area can be made sufficiently large. It is possible to easily eliminate the problems in molding such as the deterioration of the pressure and the difficulty of transmitting the pressing force of the screw as the holding pressure.

In general, if the cross-sectional area of the pinpoint gate is increased, there is a problem that when the mold is opened, it is easy to get rusted or gouged near the gate on the product side. Since it itself closes the gate and separates the product part and the runner part, not only defects such as scouring and gouging, but also the post-processing step becomes very simple.

Particularly, for a mold such as a direct gate mold in which a sprue is directly connected to a mold cavity to form a runner system, a rod material that obliquely crosses the sprue is axially driven. Since the gate opening / closing operation is performed, even if it is difficult to attach the needle along the runner system such as the sub-runner, the mechanical structure of the gate opening / closing valve is not hindered.
With the conventional two-plate type direct gate mold, it is impossible to open the mold by leaving the sprue runner on the fixed side mold side, and it is very troublesome to cut out the sprue runner from the molded product, and the material According to the present invention, the sprue runner can be left on the side of the fixed side mold to perform mold opening even if it is a two-plate type direct gate mold, which is wasteful, which is troublesome for post-processing. Waste of molding material is greatly reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an embodiment when the present invention is applied to a hot runner die.

FIG. 2 is a cross-sectional view showing an example of an embodiment when the present invention is applied to an insulated mold.

FIG. 3 is a sectional view showing an example of an embodiment when the present invention is applied to a direct gate mold.

[Explanation of symbols]

 1 Hot runner mold 2 Fixed side mounting plate 3 Fixed side back plate 4 Fixed side mold plate 5 Locate ring 6 Sprue 7 Manifold block 8 Hot tip bushing 9 Movable side mold plate 10 Spacer block 11 Movable side mounting plate 12, 13 Ejector Plate 14 Ejector pin 15 Ejector rod 16 Sprue runner 17 Main runner 18 Pin point gate 19 Sub-runner 20 Needle (gate opening / closing valve) 21 Linkage means 22 Connecting member 23 Fixed side operating rod 24 Return spring 25 Movable side operating rod 26 Plug (concave fitting) 27) Jack (concave / convex fitting means) 28 Relief surface 29 Through hole 30 Stepped through hole 31 Support pin 32 Insulated mold 33 Direct gate mold 34 Fixed side mounting plate 5 Fixed Side Mold Plate 36 Locate Ring 37 Sprue 38 Movable Side Mold Plate 39 Spacer Block 40 Movable Side Mounting Plate 41, 42 Ejector Plate 43 Ejector Pin 44 Ejector Rod 45 Fixed Side Operation Rod 46 Return Spring 47 Movable Side Operation Rod 48 Plug 49 Jack 50 Escaped surface 51 Through hole 52 Stepped through hole 53 Support pin 54 Linkage means 55 Through hole 56 Rod material (gate opening / closing valve) 57 Holding member 57a Upper plate 57b Lower plate 58 Slit 59 Rectangular groove

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kaname Kojima 3559 Kobaba, Oshinomura, Minamitsuru-gun, Yamanashi Prefecture 1559 Mold Lab Co., Ltd.

Claims (7)

[Claims] 1. A linkage means for transmitting a frontward / rearward movement of an ejector plate to a gate opening / closing valve, and a gate opening / closing valve for receiving a forward / backward movement of an ejector plate via the linkage means to open / close a gate. And the gate valve mold. 2. The gate opening / closing valve is constituted by a needle that is slidably provided in a fixed side mold in a mold opening direction and protrudes into a pinpoint gate of the fixed side mold, and the linkage means is , A movable side operation rod that is integrally fixed to the ejector plate and projects through the movable side mold plate slidably in the mold clamping mold opening direction, and slidably in the fixed side mold in the mold clamping mold opening direction. 2. The gate valve according to claim 1, wherein the gate valve is provided with a fixed side operation rod that is provided and engages with a tip of the movable side operation rod, and a coupling member that integrally connects the fixed side operation rod and the needle. Mold. 3. The gate opening / closing valve is constituted by a rod member slidably provided slidably on a sprue of a fixed side mold and protruding into the sprue, and the linkage means is integrated with an ejector plate. A movable operation rod that is fixedly attached to the movable mold plate and projects through the movable mold plate slidably in the mold clamping opening direction; and a movable operating rod that is slidably provided in the fixed mold in the mold clamping mold opening direction. -Side operation rod that engages with the tip of the side-operation rod, and holding that is integrally provided on the fixed-side operation rod and slidably holds the rod material in a plane orthogonal to the mold clamping mold opening direction. The gate valve mold according to claim 1, which is made of a member. 4. The gate valve mold according to claim 3, wherein the rod member, the movable side operating rod, the fixed side operating rod, and the holding member are symmetrically arranged with respect to the center axis of the sprue. 5. A concavo-convex fitting means which can be brought into and out of contact only when the ejector plate is at the retreat completion position is provided between the movable side operation rod and the fixed side operation rod. Item 5. The gate valve mold according to any one of items 4. 6. A fixed side mold is provided with a return spring for urging the fixed side operation rod in the mold opening direction, according to any one of claims 2 to 5.
Gate valve mold according to item. 7. The differential mechanism according to claim 1, further comprising a differential mechanism that prohibits the ejecting operation of the ejector pin until the advance amount of the ejector plate reaches a predetermined amount.
The gate valve mold according to any one of 1.