PULLING BACK METHOD FOR SMALL CALIBER PIPE BURYING EXCAVATOR AND BURIED PIPE AND DEVICE THEREOF

摘要

PURPOSE: To make use of an initial push device and an earth-moving pipe to make it possible to pull an front end excavator and a buried pipe back in the case driving can not be made in the course of the driving and burying execution of a small caliber pipe. ;CONSTITUTION: Pulling force generated in the return stroke of an initial push device is made to act on an front end excavator through an earth-moving pipe 4 laid in a buried pipe 3, so that the front end excavator is pulled back to a starting vertical shaft together with the succeeding buried pipe 3. A pull-back device interlocks a connection member 5 capable of being detached only in the case of the return stroke of the initial push device with both projections 1-6 and 4-1 of a pushing table 1-2 of the initial push device and the earth-moving pipe 4 to transfer pulling force from the pushing table 1-2 to the earth-moving pipe 4, and pushing force is not applied to the connection member 5 and earth- moving pipe 4 in the case the buried pipe is driven.;COPYRIGHT: (C)1995,JPO