Abstract: An apparatus for reconstructing railway track systems while simultaneously clearing away the bed of the old track system. A sliding seal driver is used to secure the trench formed by the removal of the old track foundation as the old track is cleared away. A new trench is cut as the apparatus proceeds on the same path as the old track. The seal driver includes lateral shields securing the trench walls as well as ground shields resting on the bottom of the trench. The lateral shields are of such lengths to secure the trench walls over the entire work area.

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 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 tunnel knife shield has a support frame, and a plurality of knife positioned side-by-side on the support frame. Each of the knives is associated with a double-acting hydraulic ram, the rams being used for advancing the knives, and for causing the support frame to follow up the advance of the knives. Hydraulic control means are provided for controlling the extension and retraction of the rams. Each ram has first and second working chambers, pressurization of which is effective to extend and retract that ram. The hydraulic control means comprises a plurality of control valves, each of which is associated with a respective hydraulic ram. Each control valve is provided with a first input constituted by a separate first hydraulic line. Each control valve is also provided with a second input, which is constituted by a common second hydraulic line. The common second hydraulic line is fed with hydraulic fluid by all of the first hydraulic lines.

Abstract: Apparatus for use in driving tunnels or the like comprises a front drive shield composed, for example, of elongate cutter knives supported for longitudinal displacement on a frame. In order to control turning motion of the shield the shield is connected via hydraulic control rams to a rear abutment such as a follow-up ring structure. The rams are all inclined relative to the longitudinal axis of the apparatus. The rams are divided into two groups inclined in opposite directions and the rams of each group can be subjected collectively to pressure fluid to impart a corrective torque to the frame.

Abstract: A tunnel knife shield has a support frame, and a plurality of knives positioned side-by-side on the support frame. Each of the knives is associated with a double-acting hydraulic ram, the rams being used for advancing the knives, and for causing the support frame to follow up the advance of the knives. Hydraulic control means are provided for controlling the extension and retraction of the rams. Each ram has first and second working chambers, pressurization of which is effective to extend and retract that ram. The hydraulic control means comprises respective first supply lines for supplying pressurized hydraulic fluid to the first working chambers, respective second supply lines for supplying pressurized hydraulic fluid to the second working chambers, and respective discharge lines for discharging hydraulic fluid from the first working chambers. Each discharge line is provided with a flow-regulation valve and a pilot-operated non-return valve.

Abstract: A hydraulic control system serves to control the operation of hydraulic rams used to position and displace an annular member which delimits a concrete reception space disposed at the rear of a tunnel-driving apparatus. The system acts to compensate for irregular loading on the annular member to ensure the latter is drawn up behind a forward drive shield without twisting or tilting. The rams are divided into groups each connectible to its own pump unit and the system connects the chambers of the rams which reduce in volume as the member is drawn up to the pump units in a manner such that the latter act as brake motors to restrain the member against the concrete pressure differential on its rear side.

Abstract: Apparatus is disclosed for regulating the capacity of a tunnelling machine. The tunnelling machine is of the type having a rotatable cutting head mounted at one end of an arm. The other end of the arm is pivotally mounted on a carrier about a pivot pin whose axis extends transversely to the axis of the arm. A hydraulic rotary drive is provided for rotating the arm about the axis of the tunnel being formed. The regulation apparatus includes a regulator for regulating the rotary drive of the arm in dependence upon the capacity of the cutting head drive. An angle/current transducer is provided for measuring the angle between the axes of the arm and the tunnel. The regulation apparatus is such that the capacity of the cutting head drive decreases as said angle decreases, the reduction in capacity being effected by a reduction in the force applied by the cutting head to the working face.

Abstract: A knife shield comprises a plurality of elongate knives which are arranged side-by-side upon a common support frame, the knives defining a generally cylindrical shield. Each knife is supported on the frame for movement in its longitudinal direction. At least one pair of diametrically opposed knives are coupled together, in the manner of a trackrod, for conjoint movement with respect to the longitudinal axis of the shield. During this movement the knives of the coupled pair concerned remain substantially parallel. The movement of the knives is used for controlling the direction of advance of the shield.

Abstract: The drive members of a drive shield, which are mounted side-by-side for longitudinal displacement as is known per se, are provided with seals or packings to close off the gaps between adjacent members. Each seal or packing is composed of two flexible resilient parts joined to respective drive members. The seal parts slidably engage one another in sealing fashion. The parts of the seal may be of the same or disimilar shape but at least one of the parts is hollow with an interior cavity which can receive pressure medium used to expand the part to urge the contacting surfaces of the parts into close sealing contact. Lubrication between the contacting surfaces to permit sliding can be achieved by employing a suitable lubricating agent as, or in, the pressure medium and by allowing some of the pressure medium to pass from the interior cavity to the contacting surfaces.

Abstract: A drive shield is formed with a series of drive or cutter members of elongate shape supported in side-by-side relationship around a tunnel wall by a frame and fluid rams are interposed between the frame and the members for effectively relative displacement. To preclude relative movement between the drive members when the frame is shifted by operating all the rams in unison a plurality of locking mechanisms with levers spring-biased into catch plates and effective between neighboring pairs of members ensures all the members lock together when they have all been shifted up by the rams. The levers are released by plates on the frame however when the frame becomes fully drawn up to permit the members to be displaced individually again. Alternatively an analogous hydraulic control system feeds identical flow rates of fluid to the rams when the frame is shifted independent of the prevailing forces or pressure to inhibit relative movement between the drive members.

Abstract: Apparatus is provided for controlling the advance of a tunnel drive shield. The drive shield is of the type having a plurality of elongate implements (or planks) which are supported and guided on a frame. Hydraulic rams are provided for moving the planks relative to the frame. The control apparatus comprises hydraulic ram means, which act between the frame and the permanent tunnel lining, and means for varying the pressure of hydraulic fluid applied to said hydraulic ram means. The frame can be advanced by applying hydraulic fluid to said hydraulic ram means and by simultaneously applying hydraulic fluid to at least one of said hydraulic rams. The direction of frame advance is controlled by varying the ratio of the pressures of the hydraulic fluid applied to said hydraulic ram means and to said at least one hydraulic ram.

Abstract: Apparatus for laying down a pipe-line in an open trench employs an advanceable shield with elongate parallel cutter planks contacting the floor and side walls of the trench. The planks are supported by a frame which is connected through hydraulic rams to a second rear frame. Means is provided to selectively lock each plank to the rear frame and the rams are operated to advance the shield and the trench. Individual pipe sections are laid end-to-end in the trench behind the rear frame and elongate thrust devices, which can be stowed in an inoperative position, are connected with the rear frame. These thrust devices are designed to engage on the free end of the pipe section last introduced into the trench and the rams are operated to move the rear frame so that the thrust device impart thrust to the pipe sections to effect their interconnection.