JPH0646927U - Ejector plate quick return device for injection mold - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] The structure is simple and it operates extremely reliably. It can be used for large and small molds and ejector strokes, and can be retrofitted to existing molds. Provided is an ejector plate rewinding device capable of performing the ejector plate rewinding. [Structure] A push bar 20 is attached to the stationary mold plate 3, and a safety plate 24 is attached to the ejector plate 6.
A push bar receiving frame 28 provided with a roller pin 23 that is movable in a direction toward and away from the safety plate is attached, and a guide rail 21 having a roller pin escape groove 26 is attached to the movable side template at all times. Install so that it touches.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an ejector plate quick return device for an injection molding die, and more specifically, after ejecting a product from the die and before the die is closed in the next mold clamping step, the ejector plate is returned to its original position. The present invention relates to an ejector plate quick rewinding device which is designed to be reverted to.

[0002]

[Background of device]

 In a plastic injection mold, the product is ejected by the ejector in the same direction as the mold opening direction. However, in the case of a product having an undercut or the like, it cannot simply be ejected in the mold opening direction by an ejector. Therefore, in such a case, a slide core that moves in a direction different from the mold opening direction is used. That is, after the slide core is pulled out from the product in a direction different from the mold opening direction, the product is ejected in the mold opening direction by the ejector.

In the case of a mold having such an undercut or the like, a mold designer usually uses a mold so that the slide core and the ejector pin do not interfere with each other in any position during any operation. Depending on the shape of the product, there are some cases where the die must be designed so that the ejector pin and the slide core may mutually interfere with each other when the die is clamped.

In the case of such a mold, after ejecting the product by the ejector pin fixed to the ejector plate, before ejecting the ejector plate before the die is closed in the mold clamping process, that is, before the ejection process. Must be returned to position. If the ejector plate does not return to its original position before the mold is closed, the slide core and the ejector pin collide with each other, and the slide core, the ejector pin, and the peripheral portion of the ejector pin are damaged. When these things get damaged, it takes a lot of time and money to repair them.

The above points will be specifically described with reference to FIGS. 8 to 10 showing a conventional plastic injection mold for molding the pipe-shaped product 13. On the fixed side, the fixed side mounting plate 1 and the fixed side template 2 are fixed to each other, and the angular pins 8 are provided in a state of being inclined outward. On the movable side, the movable side mold plate 3, the spacer block 4, and the movable side mounting plate 7 are fixed to each other, and further, the ejector pins 11 and the coil spring 10 are mounted on the upper and lower ejector plates 5 and 6, respectively. An ejector portion to which the power pin 12 is attached is provided. Reference numeral 9 is a slide core provided on the movable side. The slide core 9 has an inclined hole 9a corresponding to the angular pin 8 and has an insertion end 9b projecting inwardly inserted into the central hole 13a of the pipe-shaped product 13. Reference numeral 18 is a nozzle of the molding machine, 14 is a nozzle touch corresponding to the nozzle 18, and 15 is a sprue. Further, reference numeral 17 is an ejector rod of the molding machine, and 16 is an ejector hole formed in the movable side mounting plate 7.

In the conventional injection molding die shown in FIGS. 8 to 10, the angular pin 8 is fitted in the inclined hole 9a of the slide core 9 when the die is clamped, and the insertion end 9b of the slide core 9 is a pipe in the cavity. It is located at a position corresponding to the inside of the central hole 13a of the strip-shaped product 13. After the mold is clamped, the molten plastic is injected from the nozzle 18 of the molding machine through the spool 15 into the product-shaped cavity. After cooling the mold, the mold opening process is performed to separate the fixed side and the movable side in order to take out the solidified product 13. In the mold opening process, the slide core 9 is pushed outward by the angular pin 8 inclined outward and slides outward to open, and the insertion end 9b of the slide core 9 is inserted from the central hole 13a of the pipe-shaped product 13. Go out (see Figure 9). After the mold opening is completed, the ejector rod 17 of the molding machine penetrates the ejector hole 16 of the movable side mounting plate 7 and advances the ejector plates 5 and 6. Then, the ejector pins 11 attached to the ejector plates 5 and 6 move forward to eject the product 13. Next, in the mold clamping step, the ejector rod 17 of the molding machine retracts, and the ejector plates 5 and 6 are quickly returned to their original positions by the force of the coil spring 10 mounted on the return pin 12. At this time, the fixed-side angular pin 8 enters the inclined hole 9a of the slide core 9 and slides the slide core 9 inward to complete the mold clamping process.

However, in this mold clamping step, the ejector plates 5 and 6 are stabbed by the scraping between the ejector pin 11 and the movable mold plate 3 or the scraping between the return pin 12 and the movable mold plate 3. 10 does not return quickly, the slide core 9 sliding inward by the angular pin 8 collides with the ejector pin 11 which has been delayed in returning as shown in FIG. 10, and the slide core 9, the ejector pin 11 and the ejector pin The peripheral parts of the will be damaged.

[0008]

[Prior art]

 As a conventional ejector plate fast-returning device, (1) a device using a spring as described above, (2) a device equipped with a cam or link mechanism, and (3) an ejector rod of a molding machine and an ejector of a mold. There is a technology for using a molding machine that directly connects the plate and does not allow mold clamping when the ejector plate does not return.

[0009]

[Problems to be solved by the device]

 In the ejector plate quick return device using the spring in (1) above, the spring does not return it with a constant force from the beginning to the end of the return of the ejector plate, but with a large force at the beginning of the return of the ejector plate. However, the force becomes weaker as the ejector plate approaches the original position, and the ejector plate does not always return to the original position reliably. When a strong spring is used to avoid such a situation, the ejector plate receives the force of the ejector rod of the molding machine at the center part and the force in the opposite direction by the spring at the peripheral part. For this reason, the ejector plate is likely to be warped and deformed, and the ejector plate may not return smoothly. In addition, in case of damage or fatigue to the spring, attach a limit switch to the movable side mounting plate and the ejector plate, and control the molding machine so as not to enter the mold clamping process unless the ejector plate returns. Will be required.

In the ejector plate fast-returning device having the cam or link mechanism of the above (2), it is necessary to specially design this device according to the size of each mold, so that the cost and time are reduced. It will impose a heavy burden on the aspect.

The ejector plate fast-returning device of the above (3), that is, a molding machine in which the ejector rod of the molding machine and the ejector plate of the mold are directly connected so that the die cannot be clamped when the ejector plate does not return. However, there is a problem in that the use of the technology requires specialized knowledge to replace the mold, and it takes time to replace the mold.

The present invention has been made to solve the above problems.

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides an injection molding die in which a push bar is attached to a fixed-side die plate, and a safety plate and a roller pin movable in a direction toward and away from the safety plate are attached to an ejector plate. Install a push bar receiving frame with a guide rail that has a roller pin clearance groove on the movable side plate so that it always contacts the roller pin, and the roller pin is the part of the guide rail other than the roller pin clearance groove. The contact between the roller pin and the safety plate is a small distance that does not allow the push bar to pass, and when the roller pin enters the roller pin clearance groove of the guide rail, the gap between the roller pin and the safety plate is small. A large distance between them is sufficient to allow the push bar to pass. There is provided an ejector plate rewind apparatus characterized by was set to.

[0013]

[Action]

 In the ejector plate fast-returning device according to the present invention, when the mold is opened, the push bar attached to the fixed side mold plate is located away from the push bar receiving frame attached to the ejector plate and the guide rail attached to the movable side mold plate. It is in. At this time, since the roller pin of the push bar receiving frame is in contact with the part of the guide rail other than the roller pin clearance groove, the space between the roller pin and the safety plate is a small space that does not allow the push bar to pass. (See Figure 3). When mold clamping is started in this state, the tip of the push bar enters between the guide rail and the safety plate and contacts the roller pin, and the push bar receiving frame is pressed with the roller pin being pressed toward the guide rail. Push in the direction of the movable side mounting plate. Therefore, the ejector plate moves toward the movable side mounting plate (see FIG. 4). Immediately before the ejector plate is pushed toward the movable side mounting plate and returned to its original position, the roller pin of the push bar receiving frame begins to enter the roller pin clearance groove of the guide rail. When the roller pin is completely in the roller pin clearance groove of the guide rail, the ejector plate is completely returned to its original position, and the clearance between the roller pin and the safety plate is sufficient to allow the push bar to pass. It becomes a big interval. Therefore, the push bar passes between the roller pin and the safety plate to complete the mold clamping. That is, in the ejector plate quick return device according to the present invention, the ejector plate is surely returned to the original position before the mold is closed. In this way, the roller pin is located in the roller pin escape groove in the guide rail during mold clamping, but the mold opening process is started from this state, and the push bar separates from the push bar receiving frame. Next, when the ejector plate moves forward when the product is ejected, the push bar receiving frame moves forward, so the roller pin that can move in the direction toward and away from the safety plate escapes from the roller pin escape groove, and the roller pin and safety plate. The distance between and is a small distance that does not allow the push bar to pass through. That is, these things return to the initial state shown in FIG.

[0014]

【Example】

 Next, an embodiment of the present invention will be described with reference to the accompanying drawings. In the present invention, the injection mold itself is the same as that of the conventional one, so that the duplicated description will be omitted and only the ejector plate quick return device will be described below. In FIGS. 1 to 7 showing the embodiment of the present invention, the same reference numerals as those in FIGS. 8 to 10 are used for the same members and portions as those of the conventional mold.

The ejector plate quick return device according to the present invention is attached to a mold in place of the coil spring 10 which is mounted on the return pin 12 of the conventional plastic injection mold. A push bar 20 is attached to the stationary mold plate 2 of the mold. The push bar 20 pushes back the ejector plates 5 and 6 to their original positions via a push bar receiving frame, which will be described later. For example, a push bar 20 having a substantially rectangular cross section is used. To the ejector plates 5 and 6, a push bar receiving frame 28 having a safety plate 24 and a roller pin 23 that is movable in a direction of coming into contact with and separating from the safety plate 24 is attached. As an example of the push bar receiving frame 28, an ejector block 28a is fixed to the ejector plates 5 and 6, and one end of a pair of columns 28b and 28b is fixed to the ejector block 28a. Roller pin bearings 28c and 28c are fixed to the other ends, respectively, and safety plates 24 are laid across the roller pin bearings 28c and 28c and long holes 29 and 29 are formed in a direction perpendicular to the safety plate 24. Then, the roller pin 23 is fitted into the elongated holes 29, 29. The ejector block 28a, the column 28b, and the roller pin support portion 28c in the push bar receiving frame 28 may be integrally formed, for example. A guide rail 21 provided with a roller pin clearance groove 26 is attached to the movable side mold plate 3 so as to always contact the roller pin 23, and the roller pin 23 contacts a portion of the guide rail 21 other than the roller pin clearance groove 26. The distance between the roller pin 23 and the safety plate 24 is small so that the push bar 20 cannot pass through, and when the roller pin 23 enters the roller pin escape groove 26 of the guide rail 21, The distance between the safety plate 24 and the safety plate 24 should be large enough to allow the push bar 20 to pass through.

[0016]

[Effect of device]

 As described above, the ejector plate quick return device according to the present invention has a simple structure and operates extremely reliably. Therefore, even if the ejector plate is difficult to return due to seizure between the ejector pin and the movable side mold plate or galling, the ejector plate can be quickly and safely returned to its original position. It is possible to prevent the above-mentioned damage to the mold due to the inability to fast return. Further, the ejector plate quick return device according to the present invention can be adapted to the size of the mold and the length of the ejector stroke. Further, the ejector plate quick return device according to the present invention can be easily attached to an existing mold. Needless to say, the ejector plate quick return device according to the present invention does not impose any burden on the mold designer.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an example of an ejector plate quick return device according to the present invention attached to a mold.

FIG. 2 is a partially cutaway front view showing the mold open state of the same mold.

FIG. 3 is a sectional view showing the ejector plate fast-returning device when the mold is opened.

FIG. 4 is a cross-sectional view showing the ejector plate fast-returning device in the same way during mold clamping.

FIG. 5 is a cross-sectional view showing the same ejector plate fast-returning device as above when the mold is clamped.

6 is a sectional view taken along line VI-VI in FIG.

7 is a cross-sectional view taken along the line VII-VII of FIG.

FIG. 8 is a cross-sectional view showing a mold provided with a conventional ejector plate quick return device.

FIG. 9 is a cross-sectional view showing the mold when the mold is opened.

FIG. 10 is a cross-sectional view showing a state in which the slide core collides with the ejector pin in the same mold.

[Explanation of symbols]

 1 Fixed Side Mounting Plate 2 Fixed Side Mold Plate 3 Movable Side Mold Plate 4 Spacer Block 5 Ejector Plate 6 Ejector Plate 7 Movable Side Mounting Plate 8 Angular Pin 9 Slide Core 9a Inclined Hole 9b Insertion End 10 Coil Spring 11 Ejector Pin 12 Return Pin 13 products 13a central hole 14 nozzle touch 15 sprue 16 ejector hole 17 molding machine ejector rod 18 molding machine nozzle 20 push bar 21 guide rail 23 roller pin 24 safety plate 26 roller pin escape groove 28 push bar receiving frame 28a ejector block 28b Post 28c Roller pin support 29 Long hole

Claims (1)

[Scope of utility model registration request] 1. An injection molding die, wherein a push bar is attached to a fixed side mold plate, and a eject bar includes a safety plate and a push bar receiving frame provided with a roller pin movable toward and away from the safety plate. Attach the guide rail with the roller pin escape groove to the movable side template so that it always contacts the roller pin.If the roller pin is in contact with any part of the guide rail other than the roller pin escape groove, The gap between the safety plate and the safety plate is a small gap that does not allow the push bar to pass, and when the roller pin enters the roller pin clearance groove on the guide rail, the gap between the roller pin and the safety plate allows the push bar to pass. Characterized by making it a large enough interval Ejector plate quick return device.