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 die-assisted squeeze-forming apparatus, for bending hooks of a plate against a container e.g. a tank, is able to be used with various shapes of the plate and container without replacement of the die structure. To that end, the apparatus is provided with a calking die structure which has a plurality of divided, relatively movable dies, each movable die being subject to being individually actuated by an actuator. The preferred embodiment of the apparatus also includes a controlling means which controls the movement of the actuators and a detecting means which detects a feature of the tank which is symbolic of the size and shape of that tank. The electric signal which indicates the feature of the container is applied to the controlling means. Then the controlling means sends a respective controlling signal for controlling the movement of the actuators in order to cause an adequate rearrangement of the shape of the calking die structure should the tank be different in size or shape then the preceeding one.