JPH0411099B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an emergency stop device for an electric injection molding machine.

(B) Prior Art A conventional emergency stop device for an electric injection molding machine is disclosed in, for example, Japanese Patent Laid-Open No. 60-262617. The emergency stop device shown here operates a limit switch when a worker opens the safety door, and a signal from the limit switch immediately shuts off the power supply circuit to the motor. This causes an emergency stop to protect workers and prevent damage to the mold.

(c) Problems to be solved by the invention However, in the conventional emergency stop device as described above, even if the power supply to the motor is cut off, the stop does not occur immediately due to inertia, and the emergency stop device There is a problem that safety is not sufficient. In other words, even if the power supply to the electric motor is cut off when the safety door is opened, the inertia of the electric motor itself, the inertia of power transmission members such as the ball screw mechanism, the inertia of the screw, the movable platen, etc. will prevent the motor from being in a free state. The motor will not stop immediately and there will always be some delay. For this reason, it has been difficult to completely prevent accidents to workers, damage to molds, and the like. The present invention aims to solve these problems.

(d) Means for Solving the Problems The present invention solves the above problems by first suddenly braking the electric motor during an emergency stop, and then cutting off the power after the electric motor has stopped. That is, the emergency stop device for an electric injection molding machine according to the present invention is as follows:
A brake command device that outputs a rotation stop command signal to a drive amplifier of the motor to suddenly brake the motor when a signal from a limit switch or an emergency stop button that is activated when the safety door is opened is input; and a power cutoff command device that outputs a signal instructing to open a switch provided in a power supply circuit of the motor when a signal from a rotation detector provided in the motor indicates that the motor has stopped.

(E) Effect When the worker opens the safety door or operates the emergency stop button, the brake command device gives a rotation stop command signal to the electric motor, and the electric motor is suddenly braked. Since the electric motor is actively stopped in this way, the electric motor suddenly stops. At the same time as the electric motor stops, a power cutoff command opens a switch and stops supplying power to the electric motor. Since the electric motor is forcibly stopped in this way, there is no delay time caused by the inertia of the power transmission member, etc., and the motor is immediately completely stopped, ensuring extremely high safety.

(F) Embodiments Hereinafter, embodiments of the present invention will be described based on FIG. 1 of the accompanying drawings.

The electric motors 10, 12, and 14 serving as a driving source for the injection molding machine are, for example, a mold clamping electric motor, a plasticizing electric motor, an ejector electric motor, etc., respectively. Each of the motors 10, 12 and 14 has a rotation detector 1.
6, 18 and 20 are provided. Electric motor 1
0, 12 and 14 are controlled and operated by drive amplifiers 30, 32 and 34, which are supplied with power from power supply 22 via switches 24, 26 and 28, respectively. The switches 24, 26 and 28 and the drive amplifiers 30, 32 and 34 are controlled by signals from a control device 36, which has a brake command 38 and power cutoff commands 40a, 40b and 40c. are doing. Power cutoff command device 40a, 4
The aforementioned rotation detectors 16 and 18 are installed at 0b and 40c.
and 20 are respectively input.
Signals from limit switches 42 and 44 provided on the bed 41 of the injection molding machine and an emergency stop button 46 provided on the control box 45 can be input to the brake command device 38. Limit switches 42 and 44 are arranged to be turned on and off by a safety door 50 operated by a handle 48.

Next, the operation of this embodiment will be explained. When an operator discovers an abnormality in the injection molding machine and opens the safety door 50 or presses the emergency stop button 46, a signal is input to the brake command device 38 of the control device 36. When the signal is input, the brake command device 38 immediately outputs a rotation stop command signal to the drive amplifiers 30, 32, and 34. When the drive amplifiers 30, 32 and 34 receive the rotation stop command signal, they each start the electric motor 1.
0, 12, and 14 are suddenly braked and forced to stop. The rotations of the electric motors 10, 12, and 14 are detected by rotation detectors 16, 18, and 20, respectively, and the signals are sent to power cutoff commands 40a, 40.
b and 40c. The power cutoff commands 40a, 40b, and 40c operate the switches 24, 2 when the input rotation signal becomes 0, that is, when the electric motors 10, 12, and 14 respectively stop.
A signal is output to 6 and 28 to open them. This opens the switches 24, 26 and 28, and the power supply 22 connects the drive amplifiers 30, 32 and 3.
Power supply to 4 is cut off.

As described above, when the safety door 50 is opened or the emergency stop button 46 is pressed, the power is not simply cut off, but the electric motors 10, 12, and 14 are immediately braked suddenly to a forced stop, and then Since the power supply is cut off at the time of injection molding, the operation of the injection molding machine is immediately stopped without the time delay unlike conventional methods. This prevents the worker from getting his/her body caught between the molds, which not only improves safety, but also reliably protects the mold and the injection molding machine body.

(g) Effects of the Invention As explained above, according to the present invention, in the event of an emergency stop, the electric motor is suddenly stopped and then the power supply is cut off, so that the operation of the injection molding machine can be stopped. It can be stopped immediately, improving worker safety and ensuring protection of the mold, injection molding machine body, etc.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an emergency stop device for an electric injection molding machine according to the present invention. 10,12,14...Electric motor, 16,18,2
0... Rotation detector, 22... Power supply 22, 24, 2
6, 28... Switch, 30, 32, 34... Drive amplifier, 36... Control device, 38... Brake command device, 40a, 40b, 40c... Current interrupt command device, 42, 44... Limit switch , 46...
Emergency stop button, 50...safety door.

Claims (1)

[Scope of Claims] 1. In an emergency stop device for an electric injection molding machine that executes an injection molding process using an electric motor as a drive source, a signal from a limit switch or an emergency stop button activated when a safety door is opened is A brake command device that outputs a rotation stop command signal to the drive amplifier of the motor to suddenly brake the motor when input, and a brake command device that supplies power to the motor when a signal from a rotation detector installed in the motor indicates that the motor has stopped. An emergency stop device for an electric injection molding machine, comprising: a power cutoff command device that outputs a signal instructing to open a switch provided in a circuit.