| 摘要 |
In the area of the lower edge of the mounting plate (2) or beam for the tool is an electrical circuit which is broken or its electrical resistance is altered when the conductor is worn or affected in another manner when the cutting edge of the tool has worn away to the extent that it is level with the plate or beam lower edge. When this occurs, an optical and/or acoustic signal (16) is released. The conductor extends below the lower plate or beam edge, and upwards on the rear side of the plate or beam. It comprises an electrically uninsulated metal strip, and is tensioned between the tool cutting edge and the plate or beam. A sprung component (8f) immediately moves the one worn end of the r conductor from contact with the other end or with the tool when the conductor is worn. |
