| 摘要 |
<p>PURPOSE:To enable contact of cutter edge to be simply securely detected irrespective of the size of cutting tool by disposing a ring-shaped magnetic body wound around by a coil and surrounding a cutting tool of a cutting machine to supply AC current. CONSTITUTION:A contact sensor 10 is constituted from a ring-shaped magnetic body 11 having a portion wound with a coil, an AC generator 13, a current transformer 14, a signal processing unit 15 consisting of a detector circuit 16 and a level judging circuit 17 and a contact indicating means 18, and the magnetic body 11 is vertically provided to surround a drill 3. And when the cutting edge of drill 3 contacts a workpiece 4, an electric closed circuit 8 is formed through a cutting machine 1 and a chuck 2 so that AC current is induced by alternative magnetic flux of the magnetic body 11 due to AC current from the AC generator 13. The resultant increase of AC current from the AC generator 13 is detected by the transformer 14 and judged by the signal processing unit 15 to be indicated by the contact indicating means 18.</p> |
