Abnormality detecting apparatus for mold clamping device

Abstract

An abnormality detection apparatus for a mold clamping device, having a simple configuration that can be constructed inexpensively. A dog is mounted on the crosshead of a toggle mechanism of the mold clamping device and a proximity switch is mounted on a rear platen. The shape of the dog and the location of the mounting of the proximity switch are adjusted so that the proximity switch switches ON at a mold touch position of mold touch and switches OFF when the toggle mechanism, which generates a predetermined clamping force, locks up. An alarm is output if the length of time during which the proximity switch is ON during the process of clamping the mold or opening the mold exceeds a predetermined reference value. If in the interval from mold touch to lock-up a large load is put on a servo motor and a belt that drive the crosshead and an abnormality such as breakage of the belt or the like occurs during this interval, it can be detected at once. Simply by adding a dog and a proximity switch enables breakage of the belt to be detected with ease.

Description

technical field [0001] The invention relates to an abnormality detection device of mold clamping equipment in an electric injection molding machine. Background technique [0002] In electric injection molding machines, the movable parts of the injection molding machine are driven by electric motors. Typically, the torque of the motor is transmitted to the movable parts of the injection molding machine through a belt transmission mechanism. Even in a mold clamping mechanism using a crank lever mechanism, the motor torque is converted from rotational motion of a ball screw / nut mechanism or similar mechanism to linear motion by a conversion mechanism that moves the crosshead of the crank lever mechanism to move the movable mold half movement to complete the closing, clamping and opening of the mold halves. [0003] When the crank lever type clamping mechanism is driven by a motor through a belt and ball screw / nut mechanism or similar mechanism, after the movable mold half con...

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Problems solved by technology

[0007] However, in the methods described in JP7-16901A and JP2003-17478A, measuring devices such as pulse generators are provided on both the motor side and the driven side, and abnormalities in the belt transmission mechanism are detected, since it is necessary to provide measuring devices such as The pulse generator thus increases the cost of the injection molding machine

In addition, with the method described in JP2003-74649A, the abnormality of the belt is detected by whether or not the driven side pulley rotates, even if the driven side pulley rotates, the crosshead and the movable die cannot be guaranteed to move properly, therefore, sometimes the method is affected by the transmission mechanism Some abnormalities of the crosshead or the movement of the movable die cannot be detected

In addition, the methods described in JP2003-184967A and JP11-262932A require a tension detection device or a measuring device to detect the amount of rotation, which increases the cost of the injection molding machine

Moreover, in the method described in JP6-182845A, if the mold clamping device uses a crank lever mechanism, in the state where the crank lever mechanism is extended and generates a predetermined clamping force, the crank lever mechanism itself generates a clamping force to drive the crank lever The output torque of the motor of the mechanism crosshead decreases sharply, making it difficult to detect any abnormality in the belt transmission mechanism (such as breakage of the belt) from the motor output torque

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