JPH081066Y2 - Hydraulic safety device for injection molding machine - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic safety device for an injection molding machine, which enables a movable platen to be clamped by a mold clamping cylinder only when a safety door is closed.

[0002]

2. Description of the Related Art A hydraulic safety device for an injection molding machine is known as shown in FIG. This hydraulic safety device
In the injection molding machine in which the safety door 4 is provided on the side of the moving space of the movable platen 2 moved by the mold clamping cylinder 1, when the safety door 4 is closed in the head side pipe 7 of the mold clamping cylinder 1. A cam valve 24 is provided which opens the pipe 7 by releasing the pressure of the dog 12 on the safety door 4 and closes the pipe 7 by being pushed by the dog 12 when the safety door 4 is opened. Reference numeral 25 is an arm that presses the dog 12 of the safety door 4 and pushes the lever 24a of the cam valve 24, and rotates up and down about the shaft 26. 11 is the pipe 7,
8 is an electromagnetic switching valve. In this hydraulic safety device, if the safety door 4 is not closed, the movable platen 2 cannot be clamp-moved by the mold-clamping cylinder 1, and danger can be avoided.

[0003]

In the conventional hydraulic safety device described above, however, the arm 25 and the dog 12 are damaged, the shaft 26 is loosened, the safety door 4 swings sideways, and the roller 25a at the tip of the arm is damaged. Dog 12 and arm 25 due to wear
If the relationship between the safety valve 4 and the safety valve 4 is opened, the cam valve 2
There is a concern that the lever 4a of No. 4 is not pushed, and there is a complaint that the operation reliability is poor.

The present invention provides a hydraulic safety device for an injection molding machine in which safety is not impaired even if the relationship between the dog and the cam valve is broken due to damage or wear of the arm or dog. The purpose is to provide.

[0005]

To achieve the above object, the present invention provides a safety door beside a moving space of a movable platen moved by a mold clamping cylinder, and a pipe of the mold clamping cylinder. In addition, when the safety door is closed, the pipe is opened to enable the mold clamping movement of the movable plate by the mold clamping cylinder,
In addition, in the hydraulic safety device of the injection molding machine equipped with a cam valve that closes the pipe when the safety door is opened to prevent the mold clamping movement of the movable plate by the mold clamping cylinder, The pipe was opened by being pushed by the dog, and the pipe was closed when the safety door was opened and the pressure by the dog was released.

[0006]

[Function] Even if the relationship between the dog of the safety door and the cam valve changes due to their wear and the like, and the cam valve is not pushed by the dog when the safety door is closed, the movable platen is simply clamped by the mold clamping cylinder. The function of preventing the movable platen from being clamped in the opened state of the safety door is still retained, only by making it impossible to move. Therefore, safety is not impaired by wear or damage of the dog or the like.

[0007]

1 to 3 show an embodiment of a hydraulic safety device for an injection molding machine according to the present invention. In the figure, reference numeral 1 is a mold clamping cylinder. The mold clamping cylinder 1 moves the movable platen 2 with respect to the fixed platen 3, and a mold (not shown) between them.
Tighten the mold. A safety door 4 is provided on the front surface of the moving space of the movable platen 2 so as to be movable left and right in order to avoid a risk when the movable platen 2 is clamped. The fixed plate 3 and the safety door 4 are provided on the base 5, and the movable plate 2 is fixed plate 3.
It is slidably attached to a tie bar (not shown) fixed to the. Reference numeral 6 is a heating cylinder. The basic structure of the injection molding machine is well known.

The mold clamping cylinder 1 is connected to a hydraulic pump 9 and an oil tank 10 by pipes 7 and 8, and an electromagnetic switching valve 11 is provided in the pipes 7 and 8.

On the other hand, a dog 12 is provided on the safety door 4,
A cam valve 14 and an arm 15 are provided on the bracket 13 of the base 5. The cam valve 14 opens and closes the head side pipe 7 of the mold clamping cylinder 1 and is fixed to the bracket 13. The arm 15 is provided with a roller 15a at its tip, and is attached to the bracket 13 by a shaft 16 so as to be vertically rotatable.

When the safety door 4 moves to the right in FIG. 1 and is completely closed, the arm 15 is pushed downward by the roller 15a by the dog 12 as shown in FIG. Push down. Further, the cam valve 14 pushes up the spool by the force of the spring 14b when the safety door 4 is opened, closes the pipe 7, and rotates the arm 15 upward by the lever 14a (see FIG. 1). When the arm 15 is pressed by and the lever 14a is pressed down, the spool is pulled down to open the pipe 7.

Next, the operation of the hydraulic safety device of the injection molding machine according to the present invention constructed as above will be described. FIG.
The safety door 4 is opened and the dog 12 causes the arm 15
Indicates that the solenoid valve a of the electromagnetic switching valve 11 is excited to connect the hydraulic pump 9 to the pipe 7, but the pipe 7 is blocked by the cam valve 14 in this state. The mold clamping cylinder 1 does not extend, and the movable platen 2 does not move in the mold clamping. Therefore, danger is avoided and safety is maintained. When the solenoid b of the electromagnetic switching valve 11 is excited, the mold clamping cylinder 1 shrinks to move the movable platen 2, but there is no danger because the mold is opened.

When the safety door 4 is moved to the right from the state of FIG. 1 and closed as shown in FIG. 2, the dog 12 pushes down the lever 14a via the arm 15. This allows the cam valve 14
Is switched, and the pipe 7 which has been closed until then is opened. In this state, when the solenoid a of the electromagnetic switching valve 11 is excited, the hydraulic fluid of the hydraulic pump 9 flows through the pipe 7 to the head side of the mold clamping cylinder 1, so that the mold clamping cylinder 1 extends and the movable platen 2 moves. Move the mold clamp. Safety door 4 at this time
There is no danger because the is closed. When the solenoid b is excited, the mold clamping cylinder 1 is contracted and the movable platen 2 is moved to open the mold.

In the above, the dog 15 is damaged because the arm 15 or the dog 12 is damaged or the roller 15a or the like is worn.
If the normal relationship between the roller 15a, the roller 15a, and the arm 15 and the lever 14a is broken, the lever 14 is closed even if the safety door 4 is closed.
It happens that a is not pushed down and therefore the cam valve 14 is not switched. However, in this case, even if the solenoid a is excited, the movable platen 2 does not move in the mold clamping operation, and the mold clamping cannot be performed with the safety door 4 open. At all,
Moreover, the failure can be easily known.

Normally, two safety doors 4 are provided on the front side and the back side of the movable platen 2, but a similar safety device is also provided on the movable plate on the back side. In this case, two front and back cam valves 14,
14 is provided in series with the pipe 7. Although the movable platen 2 in the figure is configured to be directly moved by the mold clamping cylinder 1, it may be configured to be moved via a toggle mechanism or the like. It is also possible to omit the arm 15 and directly push the lever 14a with the dog 12. The structure of the arm 15 and the equipment position of the dog 12 are not limited to those shown in the figures, and are arbitrary.

[0015]

As described above, in the hydraulic safety device for an injection molding machine according to the present invention, a safety door is provided on the side of the moving space of the movable platen moved by the mold clamping cylinder, and the mold clamping is performed. When the safety door is closed, the pipe of the cylinder is opened to enable the mold clamping movement of the movable plate by the mold clamping cylinder, and when the safety door is opened, the pipe is closed to move the movable plate of the mold clamping cylinder. In a hydraulic safety device for injection molding machines equipped with a cam valve that prevents mold clamping movement, the cam valve is pushed by the dog of the safety door in the closed state to open the pipe, and the safety door is opened and pressed by the dog. When it is released, the piping will be closed, so even if the normal relationship between the dog and the cam valve is broken due to damage or wear of the dog or arm, the movable platen will move with the safety door open. This Can not, therefore danger is not safe. In addition, limit switches that operate by opening and closing the door
Control unit monitors and judges on / off signals of switches etc.
Well-known electric safety device configured to maintain safety
(Japanese Patent Laying-Open No. 2-63714), an abnormality occurs in the control unit.
If it occurs, you cannot keep it safe, but
The hydraulic safety device of an injection molding machine is, so to speak, mechanical.
Therefore, even if an abnormality occurs in the control unit, the detection device
If the (dog, arm, cam valve) operate normally,
The effect that safety can be secured because it is not affected by abnormalities in the head
There is.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of a hydraulic safety device for an injection molding machine according to the present invention, in a state where a safety door is open.

FIG. 2 is a front view showing the relationship between the dog, the arm, and the cam valve when the safety door is closed.

FIG. 3 is a side view of the same.

FIG. 4 is a hydraulic circuit diagram of a conventional hydraulic safety device.

[Explanation of symbols]

 1 Clamping cylinder 2 Movable plate 4 Safety door 7,8 Piping 12 Dog 14 Cam valve

Claims (1)

[Scope of utility model registration request] 1. A mold closing cylinder is provided with a safety door at a side of a moving space of a movable plate which is moved by the mold clamping cylinder, and the pipe of the mold clamping cylinder is opened when the safety door is closed. A hydraulic safety device for an injection molding machine that is equipped with a cam valve that allows the movable platen to be clamped by the machine and that closes the pipe when the safety door is opened to prevent the movable platen from being clamped by the mold clamping cylinder. The above-mentioned cam valve is configured to open the pipe by being pushed by the dog of the safety door in a closed state, and to close the pipe when the safety door is opened and the pressure by the dog is released. Hydraulic safety device.