JP3191990B2 - Injection mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold for molding a thick molded product with high precision.

[0002]

2. Description of the Related Art When injection molding a thick product such as a plastic lens, there is a problem that the molding cycle time becomes long because cooling is required to prevent sinking and deformation.
As a method for solving this problem, a method disclosed in Japanese Patent Laid-Open Publication No.
An injection molding method described in Japanese Patent Publication No. 21 is known.
In this injection molding method, the cavity unit is clamped by a U-shaped mold clamping member, and the mold unit is heated to a temperature equal to or higher than the glass transition point to inject the molten resin. The mold is gradually cooled to a temperature, and then released from the mold clamping mechanism of the molding machine while the mold clamping of the cavity unit is being held by itself, thereby cooling the cavity unit alone.

[0003]

However, in the prior art, since the mold clamping is self-held only by the elastic deformation force of the U-shaped mold clamping member, there is a disadvantage that the whole apparatus becomes large and complicated. . Further, in order to insert and remove the U-shaped mold clamping member, it is necessary to manually insert or remove the member using another actuator, which is a problem in promoting automation. That is, in the conventional injection molding method, the cavity unit is temporarily separated from the mold clamping mechanism of the molding machine in the cooling step,
The purpose is to shorten the molding cycle time by setting and injecting another cavity unit during that time, and if the cavity unit becomes large or automation cannot be achieved, time will be required for its movement, replacement, and removal. As a result, the original purpose cannot be achieved. The present invention has been made in view of such a problem, and it is possible to securely hold the mold clamping force by an extremely small mold clamping member, and furthermore, it is possible to self-hold and release the mold clamping force by a simple mechanism. It is an object of the present invention to provide an injection mold that can be easily automated.

[0004]

According to the present invention, there is provided an injection mold having a plurality of one of cavity units forming a cavity in parallel in a direction orthogonal to a mold opening direction. A slide plate, which is reciprocally movable in the parallel direction, a mounting member to which the other cavity unit of the pair of cavity units is removably mounted, and an insertion / removal into / from the other cavity unit. The first cavity unit freely attached to the one cavity unit;
A guide pin, a second guide pin attached to the mounting member in a detachable state in the other cavity unit, and the first and second guide pins are removably inserted and opened. A lock plate attached to the other cavity unit so as to be able to reciprocate in a direction perpendicular to the direction, the lock plate being alternately engaged with the first guide pin and the second guide pin by the reciprocal movement, and a pair of the cavity units being formed in a mold. An elastic member that urges the lock plate in the tightening direction, the pair of cavity units being in close contact with each other by engagement of the lock plate and the first guide pin, and self-holding a mold clamping force; The pair of cavity units can be separated from each other by the engagement.

[0005]

In the above construction, the lock plate engages with the first guide pin when the lock plate moves in the forward direction, and engages with the second guide pin when it moves in the backward direction.
And the pair of cavity units self-holds the mold clamping force by engagement with the first guide pin, while the pair of cavity units can be separated from each other by engagement with the second guide pin. Become. As described above, in the engagement state between the lock plate and the first guide pin, a pressing force in the mold clamping direction is applied by the elastic member, and the mold clamping force is maintained in cooperation with the elastic member. And the mold clamping force can be securely held. In response to the operation of the lock plate, the slide plate reciprocates the plurality of cavity units and shifts them to the injection position and the cooling position, so that the self-holding of the mold clamping force and the release thereof can be automated.

[0006]

Embodiment 1 FIGS. 1 to 6 show a first embodiment of the present invention. As shown in FIG. 1, a movable platen 30 and a fixed platen 31 are arranged to face each other. The fixed side plate 4 is attached to the fixed side platen 31, and the slide plate 13 is attached to the movable side attached plate 14. As shown in FIG. 2, the slide plate 13 is attached to the movable-side mounting plate 14 by forming flange-shaped rails 13a on both sides of the slide plate 13, and
Rail groove 1 into which the third rail portion 13a is slidably inserted.
4a is formed on the movable-side mounting plate 14. This slide plate 13 is, as shown in FIG.
It is connected to the actuator 16 and reciprocates in the direction of arrow E by the operation of the actuator 16. The moving direction of the slide plate 13 indicated by the arrow E is a direction orthogonal to the mold opening direction (mold clamping direction), and a plurality of (two in the illustrated example) movable side cavity units 1 are arranged in parallel along this direction. It is arranged in. The moving stroke of the slide plate 13 is longer than the pitch at which the movable side cavity units 1 arranged in parallel communicate with the nozzles 24 (see FIG. 2). By moving the slide plate 13 in the forward direction, one movable-side cavity unit 1 moves to the injection position, and the other movable-side cavity unit 1 moves to the cooling position away from the injection position. Move to the opposite position. Thereby, the plurality of movable side cavity units 1 can be switched and moved alternately.

The fixed side mounting plate 4 mounted on the fixed side platen 31 serves as a mounting member to which the fixed side cavity unit 2 is removably mounted. The fixed side mounting plate 4 includes a second guide described later. A pin 7 is provided. A nozzle 24 for injecting the molten resin is provided in the fixed-side platen 31, and an opening 4a for the nozzle 24 to advance and retreat is formed in the fixed-side mounting plate 4 (see FIG. 2).

In this embodiment, as shown in FIG. 2, the movable side cavity unit 1 and the fixed side cavity unit 2 form the cavity 5 which is brought into communication with the nozzle 24 by being in close contact with the movable side cavity unit. 1 and the fixed side cavity unit 2,
A pair of cavity units is configured. In this case, the fixed-side cavity unit 2 includes a fixed-side mold plate 3 that forms a cavity 5 with the movable-side cavity unit 1, a holding plate 10 connected to the fixed-side mold plate 3, and a holding plate 10.
And a lock plate 9 inserted therein. An elastic member 11 made of a spring is interposed between the fixed template 3 and the holding plate 10, and the fixed template 3 is an elastic member 1.
1 is pressed in a direction in which it comes into close contact with the movable cavity unit 1. Thus, the pair of cavity units including the movable side cavity unit 1 and the fixed side cavity unit 2 are in a state of being internally urged by the elastic member 11 in the mold clamping direction. Also, this elastic member 1
In addition to 1, a stopper pin 17 is provided between the fixed mold plate 3 and the holding plate 10. FIG. 6 shows a mounting structure of the stopper pin 7, wherein the screw portion of the losing portion of the stopper pin 7 is screwed into the fixed side template 3, while the shaft portion passes through the holding plate 10 and the head portion is the holding portion 10. Is in contact with This allows
The fixed mold plate 3 is movable in the mold opening direction by the length of the shaft of the stopper pin 17 with respect to the holding plate 10.

The mounting plate 10 has a central portion hollowed out in the vertical direction (not shown), and the lock plate 9 is inserted into the hollowed out portion. The lock plate 9 is connected to an actuator 8 attached to an end of the holding plate 10. The actuator 8 is, as shown in FIG.
The lock plate 9 is reciprocated in the holding plate 10 by the operation of the actuator 8, and the first guide pin 6 and the second guide pin 6, which will be described later. Is engaged with the guide pin 7 and released.

Next, the mechanism for engaging and releasing the lock plate 9 will be described with reference to FIG. A first guide pin 6 is attached to the movable-side cavity unit 1, and a second guide pin 7 is attached to the fixed-side mounting plate 4.
These guide pins 6 and 7 extend in the mold opening direction, and are arranged one by one in a left and right shifted pair as shown in FIG. In addition, the first guide pin 6 which is a pair
And the second guide pin 7 are disposed with a distance substantially equal to the stroke length C of the lock plate 9. Each of the guide pins 6, 7 has substantially the same outer diameter F, and has cut portions 6a, 7a having a D-cut shape indicated by a dimension A (see FIG. 3). In this case, the first guide pin 6 is
a is formed at the distal end portion, but the second guide pin has the cut portion 7a formed at the intermediate portion, thereby forming the first guide pin.
Guide pin 6 engages with lock plate 9 at a position where movable side cavity unit 1 and fixed side cavity unit 2 self-hold the mold clamping force (see FIG. 2), and second guide pin 7 is fixed side cavity unit. The unit 2 is engaged with the lock plate 9 at a position where the unit 2 is held on the fixed side mounting plate 4 (FIG. 4).
reference). The first and second guide pins 6 and 7 are removably inserted into the fixed-side cavity unit 2. The fixed-side mold plate 3 and the holding plate 10 at positions corresponding to the first guide pins 6. Has an insertion hole 3
a and 10c are formed, and insertion holes 3b and 10b are formed at positions corresponding to the second guide pins 7, respectively.

On the other hand, as shown in FIG. 3, the lock plate 9 has an elongated hole 9b along the moving direction of the plate 9 (the direction of arrow S), and a part of the elongated hole 9b has a large hole. An unlock hole 9c having a diameter is opened in a communicating state. The width dimension B of the elongated hole 9b is larger than the dimension A of the cut portions 6a, 7a of the guide pins 6, 7, and the guide pins 6, 7
And the hole diameter of the unlock hole 9c is formed to be larger than the outer diameter F of the guide pins 6 and 7. The length of the elongated hole 9b is determined by the stroke length C due to the movement of the lock plate 9 and the guide pins 6,7.
The minimum length is C + F / 2 to which F / 2, which is half the outer diameter F, is extended, and these dimensions are extended in the S direction and the half S direction, respectively.

When the cut portion 6a or 7a of one of the guide pins 6 or 7 is positioned in the unlock hole 9c with respect to such a lock plate, the guide pin 6 or 7 is unlocked and the lock plate 9 is unlocked. When the guide pins 6 and 7 are located in the elongated holes 9b, the guide pins 6 and 7 are locked with the lock plate 9. 3 and 5, reference numeral 9a denotes an escape hole of the nozzle 24 having a width larger than the nozzle diameter of the nozzle 24 and having a minimum stroke length C of the lock plate 9.
2 is an escape hole of the nozzle 24 formed in the holding plate 10 so as to communicate with the escape hole 9a.

Next, the operation of this embodiment will be described. When one of the pairs of cavity units shown in FIG. 1 is at the position of communication with the nozzle 24, the movable platen 30 is advanced and the mold is clamped. Then, nozzle 2
The molten resin is injected into the cavity 5 by contacting the fixed mold plate 4 with the fixed mold plate 3. Then, after removing the holding pressure, the nozzle 24
Is disengaged from the fixed side mold plate 3 and the actuator 8 is driven to move the lock plate 9 by the distance C in the direction of the arrow S. By this movement, the first guide pin 6 is locked by engagement with the long hole 9b of the lock plate 9, while the second guide pin 7 is unlocked because it is located in the unlock hole 9c (FIG. 3). Accordingly, when the movable side platen 30 is retracted, the fixed side cavity unit 2 is coupled to the movable side cavity unit 1 in a state where the parting line surface (PL surface) is in close contact. 1
And moves away from the fixed-side mounting plate 4.

Then, the second guide pin 7 is
After the mold is opened until it comes out of the nozzle, the actuator 16 is driven to move the slide plate 13, and the other pair of cavity units are moved to a position communicating with the nozzle 24. Due to the movement of the slide plate, the pair of cavity units for which injection has been completed are separated from the injection position, and are cooled. In this cooling, the first guide pin 6 and the lock plate 9 are engaged with each other so that the movable-side cavity unit 1 and the fixed-side cavity unit 2 are in close contact with each other. Becomes For this reason, even if it is a thick molded product, favorable molding without sink marks and deformation can be performed. In the self-holding state of the mold clamping force, even if a force in the extension direction acts on the first guide pin 6 due to the internal resin pressure, the PL surface does not open due to the urging force of the elastic member 11. Therefore, even if the member for self-holding the mold clamping force is small, self-holding can be reliably performed. Further, in the present embodiment, the first guide pin 6 can be provided close to the portion where the internal resin pressure acts, thereby further reducing the size.

Next, the other pair of cavity units are subjected to mold clamping, injection and actuator 8 in the same manner as described above.
After the first guide pin 6 and the lock plate 9 are locked by the above, the mold is opened. Further, the actuator 16 is driven to move the slide plate 13 backward, and is moved to a position where the pair of cooled cavity units communicate with the nozzle 24. Then, the movable side platen 30
Is advanced, the mold is clamped, the actuator 8 is driven, and the lock plate 9 is moved backward by the distance C in the anti-S direction. Thereby, as shown in FIG. 5, the first guide pin 6 is unlocked with the lock plate 9, and the second guide pin 7 is locked. Thus, since the fixed-side cavity unit 2 is coupled to the fixed-side mounting plate 4, when the movable-side platen 30 is retracted, only the movable-side platen 1 is integrally retracted, the PL surface is opened, and the molded product is taken out. (See FIG. 4). After removing the molded product, the mold is again clamped and injected, the first guide pin 6 and the lock plate are locked by the actuator 8, and the mold is opened.
The same operation is performed on the other pair of cavity units that have been injected a second time, and the molded product is taken out. Thereafter, these operations are repeated to perform continuous molding. In such an operation, the driving of the actuator 8 can be linked to the mold clamping and mold opening, and the self-holding and releasing of the mold clamping force of the cavity unit can be automated, so that the molding cycle time can be reduced. it can. Further, since the self-holding and releasing of the mold clamping force and the attachment / detachment of the cavity unit to / from the fixed-side mounting plate 4 are performed in a single operation in synchronization, there is no malfunction, and damage due to the malfunction is prevented. it can.

[0016]

Second Embodiment FIGS. 7 and 8 show a second embodiment of the present invention, wherein the same elements as those in the first embodiment are assigned the same reference numerals. In this embodiment, a connecting rod 20 extending in the S direction is attached to an end surface of a lock plate 9 reciprocally inserted into a holding plate 10, and an actuator 8 for reciprocating the lock plate 9 is attached to a fixed side. Board 4
Attached to. The connecting rod 20 has a connecting portion 20a that is bent in the direction of the fixed-side mounting plate 4 at the distal end portion. Further, the actuator 8 includes an output rod 21, and the output rod 21 is formed with an engagement hole 21 a into which the connecting portion 20 a of the connecting rod 20 is removably inserted.

In such a structure, the movable platen 30
8, the connecting portion 20a enters the engaging hole 21a, and the lock plate 9 and the actuator 8 are connected via the connecting rod 20, as shown in FIG. The reciprocal movement of the lock plate 9 by driving becomes possible. Therefore, in this embodiment,
Since the single actuator 8 operates to self-hold and release the clamping force corresponding to the plurality of cavity units, the number of parts is reduced, the configuration and assembly are simple, and the control is easy. .

[0018]

As described above, according to the present invention, even if a force in the extension direction acts on the first guide pin which self-holds the mold clamping force due to the internal pressure of the resin, the elastic member holds the pair of cavity units in the mold clamping direction. So that the parting line surface does not open. For this reason, even if it is small, it is possible to securely hold the mold clamping force by itself. Further, the reciprocating motion of the lock plate can be linked with the mold clamping and mold opening, whereby the self-holding and releasing of the mold clamping force can be automated, and the molding cycle time can be shortened.

[Brief description of the drawings]

FIG. 1 is a side view of a first embodiment of the present invention.

FIG. 2 is a partially broken side view showing a self-holding state of a mold clamping force.

FIG. 3 is a front view of a lock plate.

FIG. 4 is a partially broken side view showing a mold opening state.

FIG. 5 is a front view of a lock plate.

FIG. 6 is a sectional view showing a stopper pin.

FIG. 7 is a partially cutaway sectional view of a second embodiment of the present invention.

FIG. 8 is a partially cutaway sectional view showing the operation of the second embodiment.

[Explanation of symbols]

 Reference Signs List 1 movable side cavity unit 2 fixed side cavity unit 4 fixed side mounting plate 5 cavity 6 first guide pin 7 second guide pin 8 actuator 9 lock plate 13 slide plate

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuo Suga 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Inventor Shozo Nishida 1-6 Minami Funakoshi, Aki-ku, Hiroshima City, Hiroshima Prefecture No. 1 Japan Steel Works, Ltd. Hiroshima Works (56) References JP-A-4-361016 (JP, A) JP-A-64-36421 (JP, A) JP-A-62-299316 (JP, A) Kaihei 5-64830 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/00-45/84 B29C 33/00-33/76

Claims (1)

(57) [Claims] 1. A slide plate in which a plurality of one of a pair of cavity units forming a cavity is arranged in parallel in a direction orthogonal to a mold opening direction and reciprocally movable in the parallel direction. An attachment member to which the other cavity unit of the pair of cavity units is detachably attached; a first guide pin attached to the one cavity unit so as to be inserted into and detached from the other cavity unit; A second guide pin attached to the attachment member in a state in which it can be inserted into and detached from the other cavity unit; and the first and second guide pins are inserted in a detachable manner, and are orthogonal to a mold opening direction. Attached to the other cavity unit so as to be able to reciprocate in the same direction. A lock plate that alternately engages with the guide pin and the second guide pin, and an elastic member that urges the pair of cavity units in a mold clamping direction. The engagement between the lock plate and the first guide pin An injection molding die, wherein a pair of cavity units are in close contact with each other to hold a mold clamping force by themselves, and the pair of cavity units can be separated from each other by engagement of the lock plate and a second guide pin.