When
safety measures fail there can be grave consequences. Luckily our
client escaped unscathed when their engineer climbed into an industrial
elevator that failed to notice that the security gate had been opened.
The existing system uses limit switches to sense whether the gates are open or not, however as they are used in a dusty environment they became clogged and didn't follow the gate when it opened. This allowed the engineer to climb into the live machinery, which was still following it's automated routine and raised the lift shortly after. In this case he was completely inside the lift and was uninjured
As a result we were contacted to supply and install a more robust system on all of their machines. In order to ensure that the machine and gate can't be operated at the same time, we installed an interlocked key system so that gate can only be open with the key that runs the lift. As it is interlocked, the key can't be removed from either the gate or the control panel when in operation, preventing both from being used simultaneously.
We find that the simplest solution to a problem is usually the best and most cost-effective.
In other applications of this safety measure we have be requested to supply a spare key and declined.