CABLE PROTECTIVE PIPE WITH GROUNDING WIRES TO BE BURIED IN CONCRETE

摘要

PROBLEM TO BE SOLVED: To improve safety in drilling work with a power tool by providing grounding wires on a cable protective pipe to be buried.;SOLUTION: Electric power is supplied from a cord reel with a metal sensor to a power tool by winding the grounding wires on the surfaces and the like of the cable protective pipe to be buried. By connecting the grounding wires to a grounding main line of the cable protective pipe from the bit end of the power tool via the grounding terminal of the cord reel with the metal sensor, the grounding is conducted and this conduction is sensed by the cord reel if the bit end of the power tool contacts the grounding wires of the buried pipe with the grounding wires in the drilling work. The instant response by the metal sensor interrupts the power supply to the power tool to completely protect a cable and the like inside the cable protective pipe to be buried.;COPYRIGHT: (C)2006,JPO&NCIPI