Abstract: In a cutter structure for a shield machine which advances by boring through a tunnel wall from inside an existing tunnel, the shape of an excavating surface on a work face formed by a cutter is set so as to have a smaller curvature than or an equal curvature to the curve of a surface to be excavated on the outer face of the tunnel wall to be excavated. Since the shape of the excavating surface on the work face formed by the cutter is set by a curvature, upon advance of the shield machine by boring through the tunnel wall, the tunnel wall to be excavated, the shape of which is cylindrical, can be cut into by opening a hole which extends diametrically outward from the central portion of the cutter. As a result, the sections that are not cut into remain connected to the existing tunnel and will not enter the cutter chamber in lumps.

Abstract: An earth discharging device, for a shield machine for constructing a tunnel in the vertical direction, has a pipe for discharging downwardly earth and sand that have been excavated by the machine as it advances upwardly. An elastic film-type valve is provided in the earth discharging pipe, which valve expands and contracts diametrically by means of fluid pressure to open and close the interior of the earth discharging pipe. A gate mechanism follows the elastic valve and adjusts the sectional area of the space through which earth and sand pass inside of the earth discharging pipe. The gate mechanism narrows the sectional area of the earth discharging pipe at the outlet side of the elastic valve so as to create a substantially uniform earth pressure upon the entire elastic valve to inhibit blockages and eruptions that might otherwise occur.

Abstract: An earth discharging device, for a shield machine for constructing a tunnel in the vertical direction, has a pipe for discharging downwardly earth and sand that have been excavated by the machine as it advances upwardly. An elastic film-type valve is provided in the earth discharging pipe, which valve expands and contracts diametrically by means of fluid pressure to open and close the interior of the earth discharging pipe. A gate mechanism follows the elastic valve and adjusts the sectional area of the space through which earth and sand pass inside of the earth discharging pipe. The gate mechanism narrows the sectional area of the earth discharging pipe at the outlet side of the elastic valve so as to create a substantially uniform earth pressure upon the entire elastic valve to inhibit blockages and eruptions that might otherwise occur.

Abstract: In a cutter structure for a shield machine which advances by boring through a tunnel wall from inside an existing tunnel, the shape of an excavating surface on a work face formed by a cutter is set so as to have a smaller curvature than or an equal curvature to the curve of a surface to be excavated on the outer face of the tunnel wall to be excavated. Since the shape of the excavating surface on the work face formed by the cutter is set by a curvature, upon advance of the shield machine by boring through the tunnel wall, the tunnel wall to be excavated, the shape of which is cylindrical, can be cut into by opening a hole which extends diametrically outward from the central portion of the cutter. As a result, the sections that are not cut into remain connected to the existing tunnel and will not enter the cutter chamber in lumps.

Abstract: A guide wire for a catheter having a body portion comparatively high in rigidity and a distal end portion comparatively flexible.At least portions of the body portion and the distal end portion are formed of a super-elastic metallic member. At least portions of inner core portions on the body portion's side and on the distal end portion's side, both of which are coated by a plastic, are formed of the super-elastic metallic member, and at least a portion of the inner core portion on the distal end portion's side is made smaller in cross-section than the inner core portion on the body portion's side.In consequence, the catheter can be reliably and readily introduced to a predetermined position.