| 摘要 |
PURPOSE:To improve the efficiency of execution by connecting propellent bodies for forcing a propellent head into the ground with two bendable connections and providing an elastic seal material in one connection and a means for changing over the bent and straight state of the propellent body in the other connection. CONSTITUTION:Propellent bodies B consisting of a plurality of pipe bodies 2 for forcing a propellent head for laying a buried pipe or the like in the ground are connected with two bendable connections J. While an elastic deformable seal member 10 is interposed in one connection, a change-over means K for changing over the bendable and unbending state is provided in the other connection. When the propellent bodies B are bent, a gap therebetween is blocked from the intrusion of earth, sand, etc., and the propellent body B in the straight propulsion is prevented from bending, so that the efficiency of execution can be improved. |
