Abstract: A semi-shield method is utilized to make it possible to advance pipes for an extremely long distance in the ground. In the method, a semi-shield machine and a plurality of advance pipes are pushed one after another into the ground, and sub-pipes are interposed between adjacent advance pipes. Each sub-pipe is formed with injection holes arranged in the circumferential direction. A tail void filling material is injected under pressure into a tail void provided around the outer circumference of the advance pipes through the injection holes so that the filling material is distributed uniformly over the entire circumference of the advance pipes. With this arrangement, it is possible to reduce the friction between the outer periphery of the advance pipes and the natural ground and thus to advance the advance pipes for an extremely long distance in the ground.

Abstract: A screw-driving device, which can drive screws continuously one by one, comprises a casing coupled to a screwdriver, a slide member slidably moved in reciprocating movement in the casing and a mechanism for feeding a screw-holding tape by one-step pitches corresponding to the distances between the adjacent screws on the tape. The tape feeding mechanism includes a guide slot provided in the casing, and a two-arm lever pivotally connected to the slide member and pivotally moved to perform indexing of the screws to a position aligned with the screwdriver by a pin fitted into the inclined section of the guide slot. A pawl member with a pawl fitted into one of the grooves at one lateral edge of the tape is pivotally connected to the end of the other arm of the two-arm lever and is biased toward the tape by a spring. At the same time, a further pawl member entering one of the grooves at the opposite side of the tape is pivotally connected to the slide member and is biased toward the tape.