Patent ID: 6252513
Filing Date: 2001-06-26
Classification: B66C

Abstract:
A safety system for use with a vehicle mounted mast having an outer end and being extendable and retractable for displacing said outer end upwardly from and downwardly toward said vehicle, said system comprising: a sensor on said outer end of said mast for sensing an alternating current voltage and generating a first output signal in response thereto during displacement of said outer end upwardly from said vehicle an ultrasound transducer/detector on said outer end emitting and receiving reflected ultrasound waves for detecting a physical obstruction in the vicinity of said outer end and generating a second output signal in response thereto during displacement of said outer end from said vehicle; a microprocessor electrically connected to said detector for receiving said first and second output signal and generating corresponding first and second control signals respectively when said first and second output signals exceed a predetermined magnitude therefor, and mast control means responsive to each said first and second control signal for interrupting said displacement of said outer end.