DRIVING SHIELD WITH HYDRAULICALLY SUPPORTED FACING, AND A DEVICE FOR PROVIDING TEMPORARY MECHANICAL SUPPORT

摘要

With driving shields having facing which is supported hydraulically while the machine is advancing, it is available to provide temporary mechanical support of the facing in unstable soils if personel are to enter the cutting compartment during a stop in cutting operations, and for this reason the liquid is replaced by compressed air. The invention proposes the provision of mechanical support by the use of plates (11) which are mounted on the rear wall (3) of the cutting compartment (2) from where they can be extended by means of drive units (9) through the gaps (15) between the spokes (6) of the cutter (5) and pushed against the facing (7), and subsequently retracted again.