Machine Design

Unguarded Broach Amputates Fingers

A worker was preparing to broach a gear when he noticed a misaligned shim that would be damaged as the broaching machine started its run. As he reached into the machine to reposition the shim, he accidentally nudged the machine control into the run position with his other hand. The machine started its cycle and amputated three fingers on the man’s right hand.

The broach machine had been operating at the gear manufacturer for 25 years. During that time, someone added structures to support broach tooling, moved controls from one side of the machine to the other, and replaced a pushbutton control with a lever. No records of who had made these modification or whether that person consulted the manufacturer were found.

The injured worker sued the machine manufacturer, claiming it should have installed guards or a two-palm-button setup with antitie-down measures that would have prevented the machine from cycling while he was reaching into it. At the time the machine was manufactured, dual-palm button technology was just coming into use without antitie-down measures.

Whoever modified the machine should have added warnings to alert users to the dangers of reaching into the machine. And tooling could have been designed to prevent shim misalignment, the ultimate cause of the accident.

Even lacking these safeguards, the company that owned the machine should have added guards to prevent workers from accessing its moving parts.

OSHA had alerted the company to the need for guards nearly a year before the accident, and the company had been working on adding a light curtain. However, the unguarded machine was still being used. The safety coordinator felt that locking it out would unreasonably delay production. Instead, he relied on supervisors to verbally warn operators of the machine’s potential dangers.

Operators should have verbal and written information regarding work hazards, but these are no substitute for proper guarding and designs that can keep split-second mistakes from becoming life-changing injuries.

This month’s safety violation comes from the files of Lanny Berke, a registered professional engineer and Certified Safety Professional involved in forensic engineering since 1972. Got a safety violation to share? Send your images and explanations to [email protected].

Edited by Jessica Shapiro

Copyright 2010, Penton Media Inc. All rights reserved.

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