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Case No.12


Caught between plug table and unit frame during repair work on a plastic molding machine 
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[Circumstances of Incident]

The accident occurred at a plant that manufactures molded plastic products.

The plant operates on a 24-hour continuous basis, with three working shifts per day. On the day of the accident, the victim was working the night shift and was responsible for operating two plastic molding machines with the assistance of two foreign workers who were employed by an in-site subcontractor.

At around 30 minutes after midnight, the victim and the two foreign workers changed the die in the molding machine. When this work was completed, the victim gave instructions to the two workers to prepare the sheets of plastic material, etc., and entered the inside of the machine.

After about 15 minutes had elapsed, the voice of the victim could be heard calling "I need air!" followed moments later by a loud cry of "Air, air, air!" The two workers ran to where they heard the voice. The victim, his chest caught between the plug table and the unit frame inside the machine, was lying on his stomach with his arms outstretched.

One of the two workers who had rushed to the site was quick witted enough to open the machine's main compressed air supply valve, causing the plug table and the upper die to lift and release the victim. Although the victim's chest was heaving up and down as he tried to suck air into his lungs, his breathing had stopped after about a minute.
[Causes]
The following can be cited as the causes of this accident.

1 It is assumed that when the victim entered the molding machine, he leaned the upper part of his torso under the plug table, etc., to carry out replacement work and was replacing the controller when the plug table and upper die descended, trapping him by the chest between the plug table and the unit frame.

2 The reason the plug table, etc., descended was because the victim closed the valve of the main pipe that supplies compressed air to the molding machine. In other words, the machine employed a mechanism whereby the plug table, etc., are raised and held at the upper dead point by compressed air, but descend by their own weight when the valve is closed.

3 It is assumed that the reason the victim closed the main compressed air supply valve was the fear that compressed air would suddenly gush out when the controller was removed.
[Type of business] Plastic products manufacturing
[Type of accident]Caught
[Number of victims] One fatality
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