Patent ID: 8289170

Claim:
A system for detecting a proximity of a person to a machine, comprising: a first transmitter unit for being carried by the person, the first transmitter unit transmitting a magnetic proximity signal having a predetermined signal strength and a predetermined signal frequency; a plurality of receiver units, each of the plurality of receiver units located on the machine at a known location for receiving the magnetic proximity signal and determining a received signal strength of the magnetic proximity signal; a processing unit in communication with the plurality of receiver units and including a storage medium having data defining a first boundary around the machine, the processing unit: determining a location of the first transmitter unit relative to the machine based on the received signal strength of the magnetic proximity signal received by at least two of the plurality of receiver units and the known location of the at least two of the plurality of receiver units; and outputting a proximity warning signal if the location of the first transmitter unit relative to the machine is within the first boundary around the machine.