| 摘要 |
<p>The device has an electric driver (4), and a wire (3) connected to an automatic roller and placed along a cable (1) while being under mechanical tension. The wire extends over entire length of the cable. The roller comprises a release sensor, and an alarm i.e. siren, that is activated when the roller rewinds the wire. Overall length of the wire is automatically determined. A rigid tube (2) extends along the cable, and the wire is placed in the tube.</p> |
