Abstract: The present disclosure relates to an extendable apparatus, such as an extendable apparatus for a drill head, a drill head including an extendable apparatus, and a method of operating a drill head. The extendable apparatus includes a base section, a drive section, an extension section, and a functional section. The base section and the drive section are moveable with respect to the extension section and the functional section along a longitudinal axis. The drive section and the functional section are rotationally rigidly coupled to each other. The base section and the extension section are rotationally rigid coupled to each other, and the drive section and the functional section are rotationally moveably coupled to the extension section.

Abstract: A multi-functional connector is arranged for connecting a functional drill element to a drill head, such as an extendable cylinder of a drill head. The multi-functional connector includes a first connecting element having a first receptacle, a second connecting element having a second receptacle, and a retainer element having a retainer opening. The first receptacle has at least two driving surfaces for transferring a torque in a first direction, the second receptacle has at least two driving surfaces for transferring a torque in a first direction and in a second, opposite direction, and the retainer element has at least one retaining section to prevent a movement of a second functional drill element relative to the second connecting element in a retracting position of the second functional drill element.

Abstract: A cutting apparatus suitable for creating tunnels and subterranean roadways includes independently pivoting supports that each carry a respective independently pivoting arm and a rotatable cutting head. Each cutting head via the supports and arms, is configured to slew laterally outward in a sideways direction and to pivot in a vertical upward and downward direction. The supports and arms are mounted on a linear moving sled carried by a main frame.

Abstract: A cutter assembly for an undercutting machine for cutting a rock workface and a method of assembling a cutter assembly is provided. The cutter assembly includes a shaft mountable on the machine with one end extending from the machine, and a cutter device arranged in connection to the extended end of the shaft. The cutter device is connected releasably and rotationally rigid to the shaft with a locking arrangement. The locking arrangement includes a first locking device arranged to transfer substantially axial loads, and a second locking device arranged to transfer substantially radial loads.

Abstract: A cutting apparatus suitable for creating tunnels and subterranean roadways includes independently pivoting supports that each carry a respective independently pivoting arm and a rotatable cutting head. Each cutting head via the supports and arms, is configured to slew laterally outward in a sideways direction and to pivot in a vertical upward and downward direction. The supports and arms are mounted on a linear moving sled carried by a main frame.

Abstract: The present disclosure relates to an extendable apparatus, such as an extendable apparatus for a drill head, a drill head including an extendable apparatus, and a method of operating a drill head. The extendable apparatus includes a base section, a drive section, an extension section, and a functional section. The base section and the drive section are moveable with respect to the extension section and the functional section along a longitudinal axis. The drive section and the functional section are rotationally rigidly coupled to each other. The base section and the extension section are rotationally rigid coupled to each other, and the drive section and the functional section are rotationally moveably coupled to the extension section.

Abstract: A cutter assembly for an undercutting machine for cutting a rock workface and a method of assembling a cutter assembly is provided. The cutter assembly includes a shaft mountable on the machine with one end extending from the machine, and a cutter device arranged in connection to the extended end of the shaft. The cutter device is connected releasably and rotationally rigid to the shaft with a locking arrangement. The locking arrangement includes a first locking device arranged to transfer substantially axial loads, and a second locking device arranged to transfer substantially radial loads.

Abstract: A cutting apparatus suitable for creating tunnels and subterranean roadways includes independently pivoting supports that each carry a respective independently pivoting arm and a rotatable cutting head. Each cutting head via the supports and arms, is configured to slew laterally outward in a sideways direction and to pivot in a vertical upward and downward direction. The supports and arms are mounted on a linear moving sled carried by a main frame.

Abstract: The invention relates to an extendable cylinder (10), in particular an extendable cylinder for a drill head (2000), a drill head comprising an extendable cylinder, and a method of operating a drill head. The extendable cylinder comprises a shaft (100) with a shaft ring volume (101) between an inner part (110) and an outer part (120) of the shaft; a piston (200) with a piston ring volume (201) between an inner part (120) and an outer part (220) of the piston; the piston being moveable with respect to the shaft along a longitudinal axis (LX); a proximal end of the outer part of the piston being arranged between the inner and outer part of the shaft; and a distal end of the inner part of the shaft being arranged between the inner and outer part of the piston; and wherein the extendable cylinder is extendable and/or retractable along the longitudinal axis.

Abstract: A multi-functional connector is arranged for connecting a functional drill element to a drill head, such as an extendable cylinder of a drill head. The multi-functional connector includes a first connecting element having a first receptacle, a second connecting element having a second receptacle, and a retainer element having a retainer opening. The first receptacle has at least two driving surfaces for transferring a torque in a first direction, the second receptacle has at least two driving surfaces for transferring a torque in a first direction and in a second, opposite direction, and the retainer element has at least one retaining section to prevent a movement of a second functional drill element relative to the second connecting element in a retracting position of the second functional drill element.

Abstract: A cutting apparatus suitable for creating tunnels and subterranean roadways includes independently pivoting supports that each carry a respective independently pivoting arm and a rotatable cutting head. Each cutting head via the supports and arms, is configured to slew laterally outward in a sideways direction and to pivot in a vertical upward and downward direction. The supports and arms are mounted on a linear moving sled carried by a main frame.

Abstract: An arrangement for monitoring first and second relatively movable parts in which an actuator is connected to one of the first and second parts. The actuator includes a transponder. A sensor is connected to the other one of the two parts and has a receiver circuit with a receiver coil. A reduction coil is arranged so that its magnetic field can reduce a magnetic field of the receiver coil in a predetermined manner. The transponder touchlessly transmits a bit-coded transponder signal to the sensor when a distance between the actuator and the sensor falls below a predetermined value, and the receiver circuit compares the transponder signal to a stored bit sample for generating a monitoring output signal.

Abstract: In a method for determining a mass airflow in an air duct using a mass airflow sensor, sensor signals at successive times, indicating the magnitude of the mass airflow, are captured and, using a characteristic curve for the mass airflow sensor, corresponding values are determined for the mass airflow. In doing so, a time series of signals is subjected to a vibration analysis, which determines a fundamental vibration and at least one prescribed harmonic vibration of the fundamental vibration, and the existence of a backflow is established if the ratio of the strength of the harmonic vibration to the strength of the fundamental vibration exceeds a prescribed threshold value.

Abstract: In a method for determining a mass airflow in an air duct using a mass airflow sensor, sensor signals at successive times, indicating the magnitude of the mass airflow, are captured and, using a characteristic curve for the mass airflow sensor, corresponding values are determined for the mass airflow. In doing so, a time series of signals is subjected to a vibration analysis, which determines a fundamental vibration and at least one prescribed harmonic vibration of the fundamental vibration, and the existence of a backflow is established if the ratio of the strength of the harmonic vibration to the strength of the fundamental vibration exceeds a prescribed threshold value.