Abstract: A cross-axis cutting assembly of a selective cutting machine is provided with internally-fed spray means. The assembly includes two cutting heads supported by a boom, the cutting heads being driven by a shaft which is transverse to the boom. A high pressure water supply line for each cutting head is provided by means of a connecting member. Each connecting member is arranged externally on the boom, is preferably designed as a channelled plate, and closely fits the external contour of the associated cutting head. Each connecting member extends to the free end of the shaft, and is connected to an internal high pressure water duct formed in the associated cutting head by means of a rotary arrangement. Each rotary arrangement has an axial pin which fits sealingly into a passage.

Abstract: Pipe thrust-jacking apparatus includes a pressure ring 5 which is advanceable by a plurality of hydraulic rams 3. The rams are controlled by hydraulic control means having a plurality of hydraulic control valves 19. Each control valve is associated with a respective hydraulic ram, and is connected to a first input line and to a second input line. Each of the first input lines is connected to a respective hydraulic fluid feed line 9, and each of the second input lines 17 is connected to a common hydraulic fluid supply line 11 and to an auxiliary pump P2. The common supply line is connected to all of the feed lines. Means 12,15 are provided for selectively connecting each of the hydraulic control valves to its first input line and/or its second input line.

Abstract: A drive shield for tunnel driving has a plurality of cutters supported for longitudinal displacement on a frame. The cutters are hollow and contain double-acting hydraulic rams used to displace the cutters and the frame. The rams are linked to the cutters via alignable connector shackles and detachable bolts. To connect the rams to the frame use is made of coupling pieces which have spigots engaging through shackles on the rams. The coupling pieces pass through slots in the cutters and are guided on the frame for displacement to release or mate the spigots with the shackles.

Abstract: A hydraulic ram for use in thrust-jacking of tunnel linings comprises a cylindrical outer member, a cylindrical inner member reciprocable within the outer member, and an extension member reciprocable within the inner member. A two-part clamping ring is provided for releasably locking the extension member to the inner member. An auxiliary drive is provided for retracting the extension member rapidly within the inner member. The auxiliary drive may be a mechanical spindle drive, or a hydraulic drive having an auxiliary piston reciprocable within an axial bore formed in the extension member. The clamping ring comprises spring means for urging the parts of the clamping ring in to the closed position, and piston-and-cylinder means for urging the parts of the clamping ring apart, against the biasing force of the spring means, to open the clamping ring.

Abstract: A machine for use in mining or tunnelling has a chassis supporting a mobile arm provided with rotary cutters. A shovel beneath the arm serves to transfer material onto a pair of conveyors mounted alongside the machine chassis. This shovel is supported for vertical pivoting displacement on a beam which is itself linked via a central pivot joint to the machine chassis. Piston and cylinder units effect tilting and vertical adjustment in the shovel position.

Abstract: Apparatus for driving and lining tunnels utilizes a knife shield for driving a tunnel and shuttering for forming a concrete lining behind the knife shield. The shuttering is constituted by a plurality of shuttering elements, each of which is connected to, and inwardly off-set from, a respective knife. The shuttering elements are, therefore, advanced together with their knives and concrete is forced into the space between a shuttering element and the tunnel wall as that element is advanced.