Tunnel cutting blade - has at least two independent alternately controlled advancing blocks longitudinally spaced along chassis

摘要

The cutting blade (15) has a chassis (17) on the periphery of which is a cutting chain (18). On a part of the chassis length is an independent advance member (20) comprising at least two advancing blocks (24) which are spaced from each other longitudinally and alternately controlled. The blocks are in a housing (22) defined by two ribs (23). The blocks move in the chassis plane (M) perpendicularly to the direction (D) of the chassis movement under the control of an actuator. There is a support perpendicular to the plane (M) allowing the blocks to press against the terrain. ADVANTAGE - Overcomes the limitation of the cutter cantilever length.