JPS6123088B2 - - 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 1973.
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 the movable plate after it has moved to the mold closing position. Because the nut and its rotation device were constructed separately from the movable plate, it took time to open and close the movable plate, and further improvements were required in order to open and close the movable plate at high speed. It was hot.

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.Movable plates 3 are provided on the tie bars 2, penetrating 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.
It serves as a guide shaft 2c.

The movable plate 3 has a front plate 31 inserted into the base 2b of the tie bar 2 and a rear plate 32 inserted into the guide part 2c.
It consists of an opening/closing cylinder 4 attached to the side and an opening/closing rod 5, which are connected to each other so that they can be freely approached and separated.
A nut 6 with a gear is provided between the tie bar insertion portions 33 and 34 of both plates to be screwed into the threaded portion 2b.

This nut 6 is attached to a hollow shaft 35 in a guide cylinder formed in the tie bar insertion part 34 of the rear plate 32.
It is rotatably supported on a shaft and moved forward and backward together with the rear plate 32.

Numeral 7 is a gear that rotates the nut 6, and as shown in FIG. Can be installed freely,
A motor 9 fixed to the rear side of the rear plate 32 rotates the rear plate 32 in both forward and reverse directions.

Reference numeral 10 denotes a moving cylinder for the movable plate 3, which is attached to both sides of the connecting plate 11 fixed over the guide shaft 2c of each tie bar 2 with the piston rod 12 facing downward, and the lower end of the piston rod 12 is attached to the side of the front plate 31. are connected to each other.

In the mold clamping device having the above structure, the movable plate 3 is fixed by the operation of the movable cylinder 10 when the front and rear plates 31 and 32 are closed from the pressing position (mold opening position) of the limit switch 13 shown by the chain line. When it moves forward toward the plate 1 and reaches a position where it presses the limit switch 14 on the side of the front plate 31, the limit switch 14 causes the opening/closing cylinder 4 to extend the opening/closing rod 5, and the front plate 31 moves forward. Then, it is pushed into the tie bar base 2a by the side until the limit switch 15 is pressed.

Further, as the front plate 31 moves forward, the guide bar 36 on the front plate 31 side passes through the rear plate 32 and is in contact with the limit switch 16 disposed on the rear plate.
7 to release the opening/closing cylinder 4, and when the front plate 31 presses the limit switch 15 and stops, rotate the nut 6 and move the rear plate 32 until the limit switch 16 is pressed by the operation of the opening/closing cylinder 4. 31, screw the nut 6 into the threaded portion 2b to close the movable plate 3 to the state shown in FIG.

When the fixing of the movable plate by the nut 6 is completed as described above, the mold clamping cylinder 18 on the fixed plate side is activated to strongly clamp the molds 19 and 20.

Next, the backward movement of the movable plate 3 after injection molding is performed in the reverse order of the mold closing. First, rotate the nut 6 in the opposite direction and open both the front and rear plates 31 and 32 using the opening/closing cylinder 4. After unscrewing the nut 6 from the threaded portion 2b, move the front plate 31 backward and close the movable plate 3. , retract the piston rod 12 of the moving cylinder 10 and return it to the position where the limit switch 13 is pressed.

It should be noted that the arrangement of each of the above limit switches is arbitrary and is not particularly limited to the above embodiments. Further, the nut can be rotated individually in each part, and a chain or the like can also be used, so the rotation means can be arbitrary depending on the design.

As described above, in this invention, the movable plate 3 is composed of a front plate 31 and a rear plate 32, and the front and rear plates 31 and 32 are connected to each other so as to be openable and closable. A large-diameter base 2a that serves as a mold clamping force transmission path between the tie-bar penetration parts 33 and 34, and a small-diameter guide shaft 2c.
A nut 6 is attached to the rear plate 31 side together with a nut rotation device to be screwed onto a threaded portion 2b provided at the base tip of the tie bar 2, and a nut 6 is attached to the front plate 31 side.
Since a device is provided to move the nut to the threaded part 2b together with the movable plate, when opening and closing the mold, the movement space for the nut can be secured by the opening and closing operations of the front plate and the rear plate, and the nut is provided in the movable plate. However, there is no need to move the entire movable plate to screw in or unscrew the nut, and there is no need to move the movable plate while rotating the nut, so the nut can be rotated even when opening and closing the mold. The mold can be opened and closed at a higher speed than the conventional device, which requires

Further, since the nut can be tightened while being pressed by the rear plate, the nut does not spin idly during mold clamping, and the transition from mold clamping 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, there is no need for labor in thread machining, and the guide shaft is small in diameter, which not only reduces the weight of the tie bar, but also increases the mold clamping stroke of the tie bar. Since there is no tie bar elongation during mold clamping, the amount of oil required for mold clamping is also small.
It is also economical, as the boost time is shortened.

[Brief explanation of the drawing]

The drawings show one embodiment of the mold clamping device according to the present invention, and FIG. 1 is a partially vertical front view when the mold is closed;
FIG. 2 is a partially vertical front view when the mold has been closed, and FIG. 3 is a sectional view taken along the line shown in FIG. 2. 1... Fixed plate, 2... Tie bar, 2b...
...Threaded portion, 3...Movable plate, 31...Front plate, 32...Rear plate, 4...Opening/closing cylinder, 5...Opening/closing rod, 6...Nut, 7...
gear.

Claims (1)

[Claims] 1 A tie bar that holds the movable plate movably forward and backward with respect to the fixed plate is composed of a large-diameter base serving as a transmission path for mold clamping force, and a small-diameter guide shaft that penetrates the movable plate, and A device in which a threaded portion is provided at the tip of the base corresponding to the mold closing position, and a nut with a gear that is screwed onto the threaded portion is rotatably provided in the tie bar insertion portion of the movable plate, the movable plates are mutually connected. It is composed of a front plate and a rear plate that are connected to each other so as to be openable and closable, and the above-mentioned nut is attached to the rear plate side together with a nut rotation device between the tie bar insertion portions of both plates, and the nut is attached to the front plate side as a movable plate. A mold clamping device comprising: a device that moves to the threaded portion together with the mold clamping device.