Abstract: The device for controlling the position of a tunnelling machine has a housing (2) swivelling about an axis (3), within of which three measuring surfaces (11, 14, 18) are arranged. The first two measuring surfaces (11, 14) have openings of passage (12) for a laser beam (5), the clear width (a, c) of which diminishes in the direction of propagation of the laser beam (5). The clear width (a) of the first measuring surface (11) is smaller than the diameter (e) of the striking area of the laser beam in this measuring surface (11). The receiver elements (13, 16, 17) are arranged symmetrically in relation to the axis of the openings of passage or in case of the last measuring surface (18) in the axis and within the normal projection of the edges of the openings of passage of a preceding measuring surface (FIG. 3).

Abstract: For protecting partial-cut cutting machines from overload, a vibration sensor 7 is provided on the swivellable cutting arm 2 carrying rotatably supported cutting heads 6. The signals of the vibration sensor 7 are utilized in an electronic control 8 and used for controlling the pivotal drive of the cutting arm 2. The electronic control 8 has a threshold switch which is connected with an adjusting drive for varying the supply capacity of the hydraulic pump of the pivotal drive.

Abstract: With cutting machines, having their loading means (7) adapted to be lowered below the running surfaces (11) of the crawlers (2) of the drift advancing machine, there results an erroneous position of the machine on account of lifting the front end of the machine during such lowering movement of the loading means (7). For establishing the correct position of the cutting tool (6) and of the cutting arm (5), corrective signal are used which are released by angular position transmitters (16 or 17, respectively). By means of these angular position transmitters (16 or 17, respectively), the swivelling angle of the loading means (7) relative to the frame (1) or the swivelling angle .theta. of the operating cylinder (9) of the loading means (7) relative to the frame (1), respectively, is measured and the required corrective signal for the angle advance .DELTA..alpha. is calculated (FIG. 3).

Abstract: A method of controlling the working motion of a cutting tool of a tunnel-driving machine over the breast, wherein the actual position of the cutting tool is ascertained in consideration of the position of the tunnel-driving machine relative to the desired section of the tunnel, characterized in that at least one point of reference, which is fixed in space, is aligned relative to the longitudinal axis of the tunnel, e.g., be means of a laser beam, the times of travel of signals between at least one such point of reference and two points of the tunnel-driving machine or between at least two such points of reference and at least one point of the tunnel-driving machine are measured, the measured times of travel are subsequently utilized in a trigonometric computation of the actual position of the tunnel-driving machine, and the cutting tool is adjusted to its desired position by reference to the actual position of the cutting machine.