re: FOOT Powered Machinery.

Strictly speaking, a dead-man’s switch is a switch that has to stay depressed in order for a machine (or whatever) to function. The idea being, if something happens to the operator, the whole operation stops immediately. We used to have them on our big aerial ladders at work so the operator couldn’t move the hydraulic ladder without being directly in front of the controls. 

Not that it has to be strictly used that way, but that’s what a dead-man’s switch is!