JPH0525662B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a mold clamping method suitable for use in a vertical injection molding machine without a safety cover.

(Prior Art) Vertical injection molding machines are generally widely used for injection molding with inserts, and inserting and removing operations are performed manually or by robots.

Therefore, in many cases, a safety cover cannot be attached to improve the workability of ejecting and inserting, or to allow the ejecting and inserting machine to be moved in and out.To prevent accidents for workers, two pushbutton switches are installed on the mold clamping control circuit. A circuit was used in which the mold would not close unless the operator pressed the push button switch with both hands.

(Problems to be solved by the invention) However, conventional methods can cause electrical circuit malfunctions,
Due to valve failure, etc., the mold may be clamped even without a mold clamping instruction, and in the case of products using hydraulic mold clamping cylinders, the mold may be left open for long periods of time for mold replacement, etc. In addition, the movable platen may fall due to the dead weight of the mold clamping ram, movable platen, mold, etc., and leakage of hydraulic oil, which poses a safety problem for workers in either case.

(Means for Solving the Problems) The present invention has been made in view of the above circumstances, and its purpose is to provide a vertical hydraulic mold clamping device without a safety cover that includes electric circuits, valves, etc. To provide a new mold clamping method that prevents a movable platen from falling and injuring a worker or damaging an ejection/insertion machine even if an abnormality occurs.

According to the present invention for the above-mentioned purpose, in a vertical mold clamping device that performs a mold clamping operation by closing a mold clamping circuit by activation of two pushbutton switches, a lock rod is provided on a movable platen parallel to the direction of movement thereof, and a lock rod is engaged with the lock rod. a stopper plate that together prevents the movable plate from moving forward;
A position detector is provided for detecting the disengagement position of the stopper plate, and the stopper plate is moved to disengage the lock rod by actuation of at least one of the two push button switches. The gist of this invention is to close the mold clamping circuit and perform the mold clamping operation using both the activation signals of the two pushbutton switches and the detection signal of the position detector.

(Function) In the above method, the mold clamping operation is performed by the operator pressing two push button switches (both hands are tied).
This is possible only when the locking rod and stopper plate are confirmed to be released in conjunction with activation of the push button switch. Otherwise, the mold clamping circuit is electrically interrupted by the push button switch, and the locking rod and stopper plate are engaged to move. Mechanically lock the board.

The present invention will be specifically explained below using the illustrated apparatus.

(Embodiment) Figures 1 to 3 show a first embodiment, in which a movable platen 1 has a movable mold 2 integrally on its lower surface, and a mold clamping cylinder of a frame 4 on a machine base 3 on its upper surface. The mold is connected to a mold clamping ram 6 inserted into the mold 5, and the mold is opened and closed by raising and lowering the mold clamping ram 6 using hydraulic pressure.

A fixed mold 7 is installed on the machine stand directly below the movable mold, and when the mold is clamped, the movable mold and the fixed mold overlap to form a molded product cavity, and the molded product cavity is provided on the side of the parting surface so that it can move forward and backward. The synthetic resin material is injected by the injection device 8.

On the upper surface of the movable platen 1, a lock rod 9 having multiple engagement steps 9' is placed in parallel with the mold clamping ram 6. This lock rod 9 is provided concentrically with a through hole 11 formed in a support portion 10 that projects horizontally from the bottom of the mold clamping cylinder.

A lock cylinder 12 operated by hydraulic pressure is provided on the upper surface of the support portion 10, and a stopper plate 14 acting on the lock rod 9 is attached to the piston rod 13 of the lock cylinder 12.

The stopper plate 14 has a daruma hole 15,
When moving forward, the large diameter portion having approximately the same diameter as the through hole 11 is located above the through hole 11, so that the lock rod 9
When the movable platen 1 is moved backward, the small diameter portion of the daruma hole 15 engages with the small diameter portion of the lock rod 9 to prevent the movable platen 1 from descending.

On the side of the stopper plate 14, as shown in FIG. 2, a release confirmation switch 17 and a lock confirmation switch 16, which are proximity switches that detect the forward position (release position) and the backward position of the stopper plate 14, are provided. There is.

The lock cylinder 12 and mold clamping cylinder 5 are
They are connected to a pressure source and an oil tank via directional control valves A and B, respectively.

Although not shown in the figure, the control circuit that operates the switching valve A to the A side to perform the mold clamping operation includes two push button switches that are energized only while being pressed, and the A contact of the release confirmation switch 17, which are connected in series. One of the push button switches also acts on the circuit that operates the switching valve B in the d direction. .

In the mold open state, the lock cylinder 12 is set back so that the lock rod 9 and the stopper plate 14 are engaged with each other (as shown in Fig. 3), so that the operator can take out the molded product and insert the next insert. During this process, the movable platen 1 is prevented from descending both electrically and mechanically, and the operator completes his preparations and presses two pushbutton switches with both hands, turning on the two contacts on the control circuit. At the same time, switching valve B
is switched to the d direction, the lock cylinder 12 operates in the forward direction, and the lock cylinder 9 and the stopper plate 14 are moved forward.
release confirmation switch 17.
By turning ON (states in Figures 1 and 2), three contacts on the control circuit are closed, and switching valve A is
The mold clamping operation is performed by switching to the side.

4 and 5 show a second embodiment, in which a through hole is bored on the side of the mold of the movable platen 1 in parallel to the mold opening/closing direction, and a lock rod 9 is inserted therein. It is fixed by upper and lower lock nuts 9a and 9b.

A hole 18 for inserting the lock rod is provided in the opposite part of the lock rod 9 on the machine side, and a stopper plate 19 for opening and closing the hole 18 is provided in the middle of the hole 18, and is always pressed in the closing direction by a spring 20, so that it can move forward and backward. It is set in.

The stopper plate 19 is connected to a wire 21 on the spring 20 side, and the wire 21 passes through the spring end presser and is connected to one end of a crank 22. The other end of the crank 22 is connected to a push button switch 23.
It is in contact with the slope of an inverted triangular pyramid-shaped dog 25 located in the middle of the push button 24 that is activated by pressing. As a result, the stopper plate 19 is always pressed in the closing direction by the spring force, and the wire 21 and crank 22 are pulled by the spring force, and the push button 24 is always pushed upward.

The relationship between the stopper plate 19 and the push button 24 is such that when the stopper plate 19 closes the insertion hole 18, the push button 24 is in the uppermost position, and when the push button 24 is pushed all the way against the spring. The crank 22 is rotated along the dog 25, the wire 21 and the stopper plate 19 are pulled, and the insertion hole 18 is opened.

It should be noted that confirmation of closing and release is made by a lock confirmation switch 16 and a release confirmation switch 17, which are installed corresponding to the crank positions during both operations.

Although only one push button switch is shown in the drawing, there is another push button switch on the side of the push button 24. The switch does not operate in conjunction with the stopper plate like the one shown, but simply turns on the electricity.
It is something that turns on and off.

Therefore, while the operator is taking out the molded product and inserting the insert for the next molding in the mold open state shown in FIG. When the operator completes preparations and presses the push button and push button switch with both hands, one contact on the control circuit turns ON, and at the same time, the tip of the push button 24 activates the push button switch shown, turning on the other contact. Crank 2 by dog 25
2 is rotated, and the stopper plate 1 is rotated by the wire 21.
9 is pulled and moved back, the insertion hole 18 is opened and the release confirmation switch 17 is activated, so the third contact on the control circuit is turned on and the control circuit is closed.

As a result of the above, the directional control valve is activated and the mold clamping operation is performed.

Although the above two embodiments have been described, the present invention can also be used in vertical injection molding machines such as rotary type and sliding type, and the mold clamping hydraulic circuit can be If you operate the stylus of the mechanically operated valve installed at the same time and allow oil to pass only while the push button is pressed,
This is more suitable since it also provides hydraulic protection.

Other details such as shape, configuration, quantity, etc. can be changed as desired without departing from the spirit of the invention.

(Effects of the Invention) As described above, the present invention includes a mechanical safety device in addition to the electrical safety device, so even if an abnormality occurs in the electric circuit, valve, etc., the movable platen will not fall. Since the lock is prevented by the engagement between the lock rod and the stopper plate, it has the feature of significantly improving safety.

[Brief explanation of drawings]

The drawings schematically show a vertical injection molding machine capable of carrying out the method of the present invention, and FIG. 1 is a partially longitudinal side view of the first embodiment when the rod is open, and FIGS. 2 and 3 are views of the stopper. FIG. 4 is a partially longitudinal side view of the second embodiment when the rod is closed, and FIG. 5 is a partially longitudinal side view when the rod is open. 1... Movable platen, 3... Machine base, 5... Mold clamping cylinder, 6... Mold clamping ram, 9... Lock rod, 1
3, 19...Stopper plate, 16...Lock confirmation switch, 17...Release confirmation switch, 20...
Spring, 21...Wire, 22...Crank, 23...Push button switch, 24...Push button, 25
...Dog.

Claims (1)

[Claims] 1. In a vertical mold clamping device that performs a mold clamping operation by closing a mold clamping circuit by activating two pushbutton switches, the movable platen is provided with a lock rod parallel to the direction of movement of the movable platen, and a lock rod that engages with the lock rod to lock the movable platen. A stopper plate that prevents forward movement and a position detector that detects the engagement and release position of the stopper plate are provided, and when at least one of the two push button switches is activated, the stopper plate is moved and the locking rod is moved. The vertical type is characterized in that the mold clamping operation is performed by closing the mold clamping circuit based on both the activation signals of the two push button switches and the detection signal of the position detector. Molding machine mold clamping method.