The Portable Unit has a lot of extra electronic circuitry which measures the strength of the electromagnetic field generated by the MF4 Antenna and calculates the distance between the MF4 (LHD) and the Operator’s Portable Control Unit. This distance is used to determine whether or not the operator is a safe distance away from the LHD.
Warning Distance (W.D.)
The W.D. can be adjusted in a few seconds by an authorized mine safety person who knows the security access code. No tools or extra equipment is needed to do this. A typical W.D. would be 6m. Whenever the LHD moves to within 6 metres of the operator:
• The front and rear lights will flash on and off
• The horn will beep
• The Radio Control Unit’s display will show:
WARNING!
LHD TOO CLOSE
If the operator doesn’t move away from the LHD (or vice-versa) the Buddy System should automatically stop the LHD as described below.
Shut-Down Distance (S.D.D.)
The S.D.D. can be adjusted by an authorized safety person in just a few seconds to suit the specific application, size of the LHD etc. Remember that the Buddy System can detect an operator even if he is underneath the LHD, there is no place that the operator can hide and not be detected. A typical S.D.D. would be 4.5m. Whenever the LHD moves to within 4.5 metres of the operator:
• The engine should shut down
• The Service Brakes should be applied
• The throttle should go to idle
• The transmission should go to neutral
• Half a second later the Park Brake should be applied
Once the Buddy System has shut down the LHD, the operator must move away from the LHD, outside the W.D. (>6m) and restart the engine. The difference between the W.D. (6m) and the S.D.D. (4.5m) is 1.5m. Since the LHD travels at approx. 1m per second in radio control mode, the operator will have 1.5 seconds of flashing lights and a beeping horn to warn him to stop the LHD. If this is not enough time for the operator to react and stop the LHD (or move away) then the W.D. of 6m must be increased. In a very short time the operator will realize that it is annoying to have to keep restarting the engine and he will automatically stay outside the S.D.D., i.e., the Buddy System will train him to become a safe operator.
KEY BENEFITS:
• Self-testing ability
• Rugged
• Reliable