| 摘要 |
PURPOSE:To prevent the occurrence of noise by a method in which an impact portion provided to an intermediate tube is contacted with a stopper provided to the intermediate tube portion, and the impaction force is transmitted to an outer tube integrally connected to the itermediate tube for driving or drawing. CONSTITUTION:An elevator frame 1 is hung down from the top of a leader and supported. By operating an oil-pressure cylinder 8, an outer tube 3 is continuously reverse-driven through an intermediate tube 4 and a connecting plate 5 by a rack bar 7 and a pinion 6, and an air spring device 10 is operated to vertically vibrate the inner tube 9. The machine frame 1 is then lowered, and the outer tube 3 is penetrated into the ground by means of the continuous reverse operation of the outer tube 3 and also downward impaction force acting on the outer tube 3 upon collision of the upper impact portion against the stopper 1. When the outer tube 3 is penetrated to a given depth, the machine frame 1 is raised while charging sand into the outer tube 3 from the hopper 2 and the outer tube 3 is drawn out. |
