JPS6123089B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold clamping device used when molding synthetic resin by means such as injection or extrusion.

A mold clamping device that shortened the movement stroke of the movable plate relative to the fixed plate and simplified the mold clamping cylinder and mold closing cylinder was developed in 1974.
It is disclosed in Publication No. 22466. This mold clamping device has screws attached to the tie bars, and a nut screwed onto the screws to fix a movable plate that has been moved to the mold closing position. Because the nut and its rotation device were configured separately from the movable plate, it took time to open and close the movable plate.
In order to open and close at high speed, further improvements had to be made.

The present invention eliminates the drawbacks of the conventional mold clamping device described above and provides a device with further improved mold clamping efficiency.

The present invention will be explained in detail below with reference to the illustrated vertical embodiment.

Reference numeral 1 denotes a fixed plate attached to the machine base, and tie bars 2 are vertically fixed to the four corners of the fixed plate 1. A movable plate 3 is provided on the tie bar 2 and extends through the four corners of the fixed plate 1 so as to be able to move forward and backward. be.

Each of the tie bars 2 has a base 2a formed with a large diameter, which serves as a mold clamping force transmission path, and the tip of the base 2a, that is, the part corresponding to the mold closing position of the movable plate 3, is threaded. The movable plate 3 is formed with a threaded portion 2b, and a portion beyond the threaded portion 2b is formed to have a smaller diameter than the base portion 2a.
This serves as the guide section 2c.

4 is a moving cylinder of the movable plate 3, and the plate 5 is horizontally fixed across the upper end of each tie bar 2.
It is mounted vertically with the piston rod 6 facing downward, and the piston rod 6 is connected to the upper surface of the movable plate 3. This moving cylinder 4
In the embodiments shown in FIGS. 3 to 3, it is installed at the center of the device, but it is not necessarily limited to this location, and as in the embodiment shown in FIG. 4, it is installed on both sides of the device. In some cases, it may be installed with the

The movable plate 3 has diver insertion portions 7 at the four corners.
A nut 9 with a gear, which is screwed into the threaded part 2b of the tie bar 2, is housed in a space 8 formed in the insertion part 7 so as to be movable in the axial direction of the tie bar 2 together with a spring 10. . The nut 9 also communicates with a rotating device operated by a motor attached to the movable plate side, and the rotating device allows the screw portion 2 to
b and then put back together.

5 and 6 illustrate the nut 9 and the rotating device, and FIG. 5 shows the movable plate 3 installed in the space 8 parallel to the tie bar 2.
A motor 13 on a side guide bar 11 and a guide plate 12 provided between the guide bar 11 and the nut 9.
and a gear 15 for rotating the nut, which is attached to the drive shaft of the motor 13 and meshed with a gear 14 on the outer periphery of the nut. After the movable plate 3 is moved forward to the mold closing position by the movable cylinder 4, it can be screwed into the threaded portion 2b by a gear 14 rotated by the motor 13. Further, the completion of screwing in the nut 9 and the completion of unscrewing are determined by a limit switch 1 arranged at a predetermined interval on the side of the guide bar 11.
6 and 17, and this causes the motor 13 to
It is intended to stop.

Next, the rotating device shown in FIG.
A drive shaft 18 on the side of the movable plate 3 rotatably supported in the space 8 in parallel with the drive shaft 18, a motor 19 connected to one end of the drive shaft 18, and a key or spline attached to the drive shaft 18 in the axial direction. It consists of a gear 20 for rotating the nut which is movably attached and meshed with a gear 14 on the outer periphery of the nut 9. The drive shaft 18 driven by the motor 19 and the gear 20 are used to screw in and unscrew the nut 9. is becoming possible.

To explain the operation of the above embodiment in order, the movable plate 3, which has retreated to the position of the mold opening stop limit switch 21 disposed above, is moved from the position shown in FIG. 1 by the moving cylinder 4 toward the fixed plate 1. When you move forward and press the limit switch 22 shown in FIG. 2, the movable plate 3 slows down and at the same time, the rotating device for the nut 9 shown in FIG. It rotates while being pressed and is screwed into the threaded portion 2b. When the movable plate reaches the position where the limit switch 23 is pressed, that is, the mold clamping position, the movable cylinder 4 stops and stops moving forward, but the nut 9 continues to rotate until screwing is completed.

When the screwing of the nut 9 is completed, the ram of the strong mold clamping cylinder 24 provided on the fixed plate 1 rises to strongly clamp the mold 25 on the movable plate side and the mold 26 on the ram.

After performing strong mold clamping as described above,
Synthetic resin is injected into the mold, and the mold clamping force transmission path in this case is the movable plate 3, tie bar 2, and fixed plate 1 via the nut 9 screwed onto the threaded portion 2b. .

Next, when the injection is completed, the strong mold clamping is first released by the retreat of the ram, then the nut 9 is reversely rotated and unscrewed from the threaded portion 2b, and then the nut 9 is unscrewed from the threaded portion 2b by the tension of the movable cylinder 4. The movable plate 3 is returned together with the nut 9 to the original position shown in FIG.

In the embodiment shown in FIG. 4, since the mold clamping cylinder 24 is provided on the movable plate 3 side, the only difference is the operating direction of the mold clamping ram, and the other steps are the same as in the above embodiment.

As described above, this invention forms a space 8 in the tie bar insertion part 7 of the movable plate 3, and in the space 8, a large diameter base 2a serving as a mold clamping force transmission path and a small diameter guide part 2c are provided. A nut 9 with a gear screwed to a threaded portion 2b provided at the tip of the base of the tie bar 2 is housed movably in the axial direction of the tie bar 2 together with a spring member 10, and is constantly pressed in the direction of the threaded portion. The movable plate 3 is a device that communicates with a nut rotation device provided on the movable plate and moves the nut 9 together with the movable plate 3 to the threaded portion 2b.
Since the nut is provided in the mold, there is no need to move the movable plate while rotating the nut when opening and closing the mold, and the nut only rotates when the nut is in contact with the threaded part, so the nut does not rotate when opening and closing the mold. The mold can be opened and closed faster than the conventional device that requires rotation.

In addition, since the nut is always pressed in the direction of the threaded portion, the nut does not spin idly during mold clamping, and the transition from mold closing to mold clamping can be performed quickly and reliably.

Furthermore, since the threaded part of the tie bar is only at the tip of the base, it does not take much time to process the thread, and the guide part is small in diameter, which not only reduces the weight of the tie bar, but also reduces the weight of the tie bar.
Since the clamping stroke of the tie bar does not become long, the extension of the tie bar during mold clamping is small, the amount of oil required for clamping the mold is small, and the pressurization time is shortened, which is also economical.

[Brief explanation of the drawing]

The drawings show an embodiment of the mold clamping device according to the present invention, and FIG. 1 is a partially longitudinal front view of the first embodiment when the mold is opened, and FIG. 2 is a partially longitudinal front view when the mold is closed. , Fig. 3 is a partially longitudinal front view during strong mold clamping, Fig. 4 is a partially longitudinal front view of the second embodiment, and Figs. 5 and 6 are movable plates showing an embodiment of the nut rotating device. FIG. 1... Fixed plate, 2... Tie bar, 2b...
...threaded part, 3...movable plate, 7...penetration part,
8... Space part, 9... Nut, 13, 19... Motor, 15, 20... Gear.

Claims (1)

[Scope of Claims] 1. A tie bar that holds the movable plate movably forward and backward with respect to the fixed plate is comprised of a large diameter base serving as a transmission path for mold clamping force and a small diameter guide portion that penetrates the movable plate. In the device, a threaded portion is provided at the tip of the base corresponding to the mold closing position of the movable plate, and a geared nut screwed to the threaded portion is rotatably provided in the tie bar insertion portion of the movable plate, A required space is formed in the tie bar insertion portion of the movable plate, and the nut is housed in the space so as to be movable in the axial direction of the tie bar together with a spring member, and is constantly pressed in the direction of the threaded portion. A mold clamping device characterized in that the movable plate is provided with a device that communicates with a nut rotating device attached to the movable plate and moves the nut together with the movable plate to the threaded portion. 2 The nut rotating device consists of a guide bar attached to the movable plate side in parallel with the tie bar, a motor on the guide plate provided between the guide bar and the nut, and a motor attached to the drive shaft of the motor and mounted on the outer periphery of the nut. The mold clamping device according to claim 1, comprising a gear and a nut rotation gear meshed with the gear. 3 The nut rotating device has a drive shaft that is rotatably attached to the movable plate side in parallel with the tie bar, and a drive shaft that is attached to the drive shaft so as to be movable in the axial direction with a key or spline, and meshes with a gear on the outer periphery of the nut. A mold clamping device according to claim 1, comprising a nut rotation gear.