Lumber grader's arm caught in rollers of grading table

Friday, July 20, 2007

What happened?

A worker on the midnight shift was standing near the outfeed area of a grading table. A drive motor shaft was located at the end of the table. The drive shaft extended the full width of the rollers, from the drive motor and belt on one side to a contact point on the other. The worker may have been trying to stabilize his position when his gloved left hand came into contact with the rotating shaft. His wrist and arm were quickly wound between the shaft and the last roller bar. The worker’s thumb was broken and his lower arm was fractured in two places.

Why did it happen?

Apparently the worker was tired and leaning or sitting at the end of the rollers. He may have lost concentration or even dozed off, placing his gloved hand on the rotating drive shaft. The drive shaft extended across the full width of the rollers, even though the motor was actually driving the mechanism from only one side.

How can it be prevented?

  • Proper guards should be in place to prevent contact with exposed rotating parts of the grading table that pose a risk to the grader.
  • Stools may remedy the tendency of a worker to lean if tired of standing.
  • The drive mechanism need not extend across the full width if it is acting from only one end. This would facilitate a guard that could cover the entire mechanism and leave no moving part exposed.
  • Workers must be trained in safe operating procedures and supervisors must conduct post-training reviews and ongoing monitoring to ensure compliance.