| 摘要 |
<p>PURPOSE:To prevent the drooping of a cable by a method in which when a machine to move the tip of cable is retracted, a winding drum is turned, and also when the machine is advanced, a part of oil is allowed to escape through a relief valve to enable the drum to be turned backwards. CONSTITUTION:When a mobile machine connected to the tip of a cable to be wound around a winding drum 3 is retracted, an oil-pressure pump 6 is operated by an air motor 5 and the drum 3 is turned by an oil-pressure motor 6 to wind the cable around the drum 3. When the mobile machine is advanced, the drum 3 is turned backwards. Although overloads are applied to the pump 6 and the pressure of oil is increased, a relief valve 14 is operated by the oil pressure so increased to allow a part of the oil to escape. Therefore, a fixed tension is given to the cable while allowing the drum 3 to turn reversely, and the drooping of the cable can be prevented. A drive air pipe 10 is led into an oil tank 4 to prevent the overheating of oil.</p> |
