TUNNEL SHIELD Russian patent published in 1996 - IPC

FIELD: mining industry. SUBSTANCE: tunnel shield includes frame, shell, shield and support hydraulic jacks which rod spaces are connected to outlet of reversible distributor and which piston spaces are connected to outlets of corresponding two-position distributors and thrust device mounted in shield shell which incorporates three hinge-joined parts coupled by means of spacing power cylinder fitted with restoring straps on side of lining ring and with sealing straps on side of shell and coupled to support hydraulic jacks with the use of spherical joints. Thrust device is connected to two support hydraulic jacks by means of cross-piece mounted for movement in cylindrical bushings of brackets attached with their spherical joints to rods of support hydraulic jacks and is additionally coupled with swing joint to third support hydraulic jack. In this case upper parts of thrust device are connected to cross-piece with the aid of cylindrical joint. Sealing straps are anchored on extending elements put in body of thrust device by means of adjustment screws for movement in radial direction. Inputs of two-position distributors of shield hydraulic jacks are connected to second input of reversible distributor through check valve and pressure spool which drain line is coupled to second outputs of two-position distributors of support hydraulic lacks which inputs are coupled to second output of reversible distributor through hydraulic lock. Its control space is connected through throttle to rod spaces of hydraulic jacks and to drain through additional pressure spool which control line is connected to second inputs of two-position distributors of shield hydraulic jacks and spacing power cylinder. EFFECT: expanded application field in construction of tunnels with prefabricated lining. 5 dwg