| 摘要 |
<p>PURPOSE:To perform cable extension work safely, quickly and surely by arranging a magnetism detection device to detect the proximity of a magnetic substance near an extension cable metal block and by controlling the tensile force of extension cable for an aerial transmission line in accordance with a proximity signal from this magnetism detection device. CONSTITUTION:When a protector 3 whose diameter is of an expanded section comes close to an extension cable metal block 4 on a pylon, a magnetic substance 6 at the tip of the protector 3 is detected with a detection coil 5. The output of this magnetism detection coil 5 is amplified and inputted into a control device 6. The speed change gear of a capstan 7 for an engined car is controlled so that the receiving speed will decrease as the output of the magnetism detection coil 5 increases and the former will increase as a latter decreases. It will be returned to the original receiving speed when the protector 3 passes. In this way, the cable extension work can safely and quickly be performed since when the expanded section of the transmission line passes through the extension cable metal block, the control is automatically performed so as to reduce the tensile force of the extension cable.</p> |
