In Reply to: OSHA clears J.R. Wheel for restart; Worker at the factory was killed over weekend in incident with robot posted by Bryan Haywood on 01/18/02 at 11:04 PM:
What very little of which was said in these posts is what type of robot was it and what type of interlocks did it have. I'm from Australia and we had a robot death not unlike this one about a year and a half ago. What our incident told us was that some of our robot suppliers didn't know how to guard them or worse didn't care.
The robot was an Adept palletiser and only had a single channel Cat B (En 954) safety system. The single gate switch (key type) failed (the key snapped off and stayed in the lock). The result was that the operator went into the cell with the robot still powered up and it killed him.
As far as I and my company is concerned any robot not installed to at least cat 3 (En 954), that is to say it has dual channel safety circuits with some fault detection, then whoever sold it, who ever installed it DID NOT DO THEIR JOB.
Most of the better robot manufacturers (Kuka, ABB, Adept) either sell Cat 3 robots or have the option so there really isn't excuse for not doing the job right. If you have any doubts the European Standard EN 775 is a good start. If the robot isn't up to this standard DON'T BUT IT.
I absolutely agree with Chris in that its a bitch to see maintenance personnel defeating safety systems. But if we as control system engineers know what we are doing its not that difficult to make the safeties tamper resistant. There are lots of ways to keep the idiots from hurting themselves.
The other big bug to me are the clowns whos sell robots and other machines that don't have acceptable safety systems. My next least favoured person is the client who will not pay for a decently designed safety system or buys a cheaper (minus safety) machine. This guy is real clever as he wants to save a grand or 2 on a million dollar project and risk some one elses life and a multi-million dollar law suit.
Bottom line is if the smart people do the right thing then the grunts on the shop floor get to go home at the end of the shift.