| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a boring tool which allows a user to know that a hole is formed to a desired depth even though the boring tool is not equipped with a gauge. <P>SOLUTION: An amplifying circuit A can amplify a voltage output from a distance sensor at a first amplification rate. An amplifying circuit B can amplify a voltage outputted from the distance sensor at a second amplification rate larger than the first amplification rate. A computing unit composed of a microcomputer has an upper limit value Vmax and a lower limit value Vmin to readable voltages. For a section Va and a section Vb between the upper limit value Vmax and the lower limit value Vmin, ranges for allowing the measurement of distances versus voltage values within a given error tolerance are determined to be a distance range LA1 or larger and LA2 or smaller and a distance range LB1 or larger and LB2 or smaller. The microcomputer selects either the section Va or section Vb, and based on voltage values corresponding to the selected section, determines a distance between a material to be bored and the distance sensor. <P>COPYRIGHT: (C)2012,JPO&INPIT |
