CONNECTING MECHANISM OF EXPANSION PART ON MOVABLE BED BASE

PURPOSE:To cope with movement in the curving direction in the case of drilling a tunnel by connecting a front end part or a rear end part of a cylinder free to adjust to expand it to alternately slide a front bed base and a rear bed base through a universal joint by way of simultaneously expanding and actuating both of them. CONSTITUTION:A jack is previously set on a front end side surface of a front bed base 1 in the case of sliding a movable bed base to the side of a facing in construction of a curved tunnel. In the meantime, cylinders 4 free to adjust to expand are aligned in parallel with equal intervals on an expansive part 3 which is a connected part of the front bed base l and a rear bed base 2, a front end part 4a of a rod is connected to a rear end part of the front bed base 1 through a universal joint 5, and a rear end part 4b is connected to a front end part of the rear bed base 2 through a horizontal connecting pin 6. All the cylinders 4 (jack group) are actuated, the piston rod is pushed out in the full stroke, the front bed base 1 is slid forward in the full stroke, and the front end part of the front bed base 1 is slid sideways by the jack. Consequently, the front bed base 1 made to advance along a curve of the tunnel to be drilled.