Patent ID: 7768549

Claim:
A mutual exclusion mechanism for a hazardous machine, wherein at least a portion of the machine and at least a portion of an operator can move into and out of a mutual exclusion zone during operation of the machine, but not at the same time, the mechanism comprising: a sensor that detects a first entrance of one of the portion of the operator or the portion of the machine into the mutual exclusion zone via any of a plurality of border segments bordering the mutual exclusion zone, wherein the sensor and the mutual exclusion zone do not move with the moving portion of the machine; and a controller that receives information from the sensor regarding the first entrance into the mutual exclusion zone, and controls the machine based on a second entrance of the portion of the operator or the portion of the machine into the mutual exclusion zone via a second segment bordering the mutual exclusion zone, wherein when a portion of the operator enters the mutual exclusion zone the controller prevents a portion of the machine from entering the mutual exclusion zone until the portion of the operator exits the mutual exclusion zone, at which time the controller allows the portion of the machine to enter the mutual exclusion zone.