The invention relates to a bit holder for an earth working machine, in particular a surface miner, a road milling machine, or the like, having a holding projection that comprises a bit receptacle and/or carries a cutting element. In order to improve the operating reliability of an earth working machine, provision is made according to the present invention that the holding projection has, behind the cutting element or behind a receiving region of the bit receptacle in the tool advance direction, a wear protection element having a hard-material element in order to provide an emergency-mode property.

The invention relates to a bit holder for an earth working machine, in particular a surface miner, a road milling machine, or the like, having a holding projection that comprises a bit receptacle and/or carries a cutting element. In order to improve the operating reliability of an earth working machine, provision is made according to the present invention that the holding projection has, behind the cutting element or behind a receiving region of the bit receptacle in the tool advance direction, a wear protection element having a hard-material element in order to provide an emergency-mode property.

A combination bit and bit holder assembly includes a bit holder having a forward body portion and a shank. The forward body portion includes an upper end and a lower end. An insert is mounted in the bore of the upper end of the body portion. The insert also includes a central bore that receivingly retains a receiving cup. The receiving cup includes a bottom portion and an annular flange that extends from the bottom portion and defines a hollow forward portion. A bit is mounted in the hollow forward portion of the receiving cup which is configured to have a ductility that provides impact absorption to the bit.

A combination bit and bit holder assembly includes a bit holder having a forward body portion and a shank. The forward body portion includes an upper end and a lower end. An insert is mounted in the bore of the upper end of the body portion. The insert also includes a central bore that receivingly retains a receiving cup. The receiving cup includes a bottom portion and an annular flange that extends from the bottom portion and defines a hollow forward portion. A bit is mounted in the hollow forward portion of the receiving cup which is configured to have a ductility that provides impact absorption to the bit.

A mounting block assembly and method for assembling is disclosed. The mounting block assembly may comprise a mounting block and a toolholder. The mounting block may include a flighting portion, a mounting portion and a protrusion. The mounting portion defines a first bore that is configured to receive a toolholder. The toolholder includes a generally cylindrical sidewall that defines an axis and defines a second bore that is configured to receive a stem of a cutting bit. The sidewall includes a pair of radially outward extending prongs that define a first recess between the prongs. The first recess is configured to interlockably receive the protrusion when the toolholder is disposed in the mounting portion, wherein the interlocked configuration of the toolholder and the mounting block inhibit rotational movement of the toolholder about the axis.

A tunnel tunneling system includes a bolter miner, a bolter-integrated transportation machine, a transfer machine, a self-moving tail and a belt conveyor. The bolter miner includes a rack, a cutting device, a drilling device and a control device. The cutting device is arranged on the rack and is swingable in an up-down direction, and has a lowest swing angle and a highest swing angle. The drilling device is arranged on the rack, and includes a drilling rig and a sensor. The drilling rig is configured to drill a tunnel floor and/or a tunnel roof, and the sensor is configured to monitor a set parameter of the drilling rig and generate a monitoring data signal when the drilling rig is drilling. The control device is configured to receive and analyze the monitoring data signal.

A tunnel tunneling system includes a bolter miner, a bolter-integrated transportation machine, a transfer machine, a self-moving tail and a belt conveyor. The bolter miner includes a rack, a cutting device, a drilling device and a control device. The cutting device is arranged on the rack and is swingable in an up-down direction, and has a lowest swing angle and a highest swing angle. The drilling device is arranged on the rack, and includes a drilling rig and a sensor. The drilling rig is configured to drill a tunnel floor and/or a tunnel roof, and the sensor is configured to monitor a set parameter of the drilling rig and generate a monitoring data signal when the drilling rig is drilling. The control device is configured to receive and analyze the monitoring data signal.

A distributed coal cutting device for a Longwall face of a coal mine includes coal cutting units, where each coal cutting unit includes one coal cutting machine and two hydraulic supports, the two hydraulic supports are arranged side by side, the arrangement direction of the two hydraulic supports is parallel to the coal wall of the Longwall face, and the coal cutting machine is connected with one of the hydraulic supports. According to the device, multiple coal cutting machines are used for simultaneously carrying out coal cutting operation, and single-point coal cutting is changed into multiple-point simultaneous coal cutting, so that the coal cutting production capacity and the production efficiency are greatly improved. The multiple coal cutting machines can derive multiple control modes, so that the production flexibility and adaptability are improved.

A distributed coal cutting device for a Longwall face of a coal mine includes coal cutting units, where each coal cutting unit includes one coal cutting machine and two hydraulic supports, the two hydraulic supports are arranged side by side, the arrangement direction of the two hydraulic supports is parallel to the coal wall of the Longwall face, and the coal cutting machine is connected with one of the hydraulic supports. According to the device, multiple coal cutting machines are used for simultaneously carrying out coal cutting operation, and single-point coal cutting is changed into multiple-point simultaneous coal cutting, so that the coal cutting production capacity and the production efficiency are greatly improved. The multiple coal cutting machines can derive multiple control modes, so that the production flexibility and adaptability are improved.

A mining machine including a chassis, an actuator, a cutter drum supported by the chassis, the cutter drum driven by the actuator, a cutter bit coupled to the cutter drum, and a controller. The controller includes a processor and memory and is configured to measure a characteristic of the actuator, determine the cutter bit is worn based on the measured characteristic of the actuator, and output a signal when the cutter bit is determined to be worn.