Gewerkschaft Eisenhutte Westfalia, Gmbh

Walter Hohn

Herbert Heitkamp

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. The flow-regulation valves control the rate of retraction of the rams. The pilot lines of the non-return valves are connected to the associated second supply lines, so that these valves open automatically when the second working chambers are pressurized.

Hydraulic control means

A drive shield of a tunnelling apparatus has elongate drive members supported and guided for longitudinal movement in a manner known per se. The drive members are connected to rear members or tails forming a rear shield and fluid concrete is introduced into a reception space within the rear shield to create a permanent lining for the tunnel. The rear members are shaped or profiled to provide recesses which are closed-off over a certain zone with the aid of covers. Reinforcing bars or the like can be inserted into the recesses to become cast into the concrete lining and means for delimiting the front end of the concrete reception space, such as a ring component, engages on the covers which form a smooth continuous bearing surface therefor.

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Munich, Georgia

Walter Hohn