TUNNEL SHIELD AND SEALING UNIT Russian patent published in 1997 - IPC

FIELD: underground construction, in particular, tunnel shields with turning cutter section; may be used in construction of tunnels with small radii of curvature. SUBSTANCE: tunnel shield consists of cutter section, body, shield hydraulic cylinders installed in supporting rings of cutter section and body, and sealing unit between cutter section with the help of pivoting bearing, and freely installed in supporting ring of cutter section, front supporting ring and rear supporting ring of shield body. Shield hydraulic cylinders are rigidly secured to front supporting ring of shield body and freely installed in supporting ring of cutter section. This makes it possible to use shield hydraulic cylinders, both for shield advancing and for turning the cutter section. This provides for exclusion of twisting and transverse displacement of cutter section or shield body relative to each other. Sealing unit between cutter section and body is made in the form of bending sheet, flexible rings and spacer. Bending sheet is located in annular recess of cutter section with clearances in which flexible rings are installed. Bending sheet is secured to body in its annular recess with the aid of flexible spacer. Sealing unit allows compensation of transverse displacement of cutter section or body relative to each other in turning of cutter section, and preclude formation of nonsealed clearances between cutter section and shield body. EFFECT: higher efficiency. 7 cl, 6 dwg