Epiroc Rock Drills Aktiebolag

Gustav Mörtzell

Thomas Adolfsson

The invention relates to a method for determining the state of a joint joining a first and a second drill string component. A drill rig includes a rotation unit for rotating the drill string and means for determining a representation of a torque applied by the rotation unit. A joint loosening mechanism distinct from the rotation unit apply a joint loosening torque acting on the drill string when loosening a joint. The method includes applying a torque in a joint loosening direction by means of the rotation unit, and applying a joint loosening torque acting on the drill string by means of the joint loosening mechanism.

Method and system for detecting a loosened joint of a drill string

The invention relates to an arrangement for controlling a rock drilling machine during an extraction of a drill string from a drilled bore, the rock drilling machine being movably arranged on a feeder, the arrangement comprising an actuator arranged to move the rock drilling machine in a direction opposed to a drilling direction along the feeder, a rotation motor arranged to rotate the drill string, and an actuator controller arranged to control the actuator during the extraction of the drill string from a drilled bore, the actuator controller being arranged to control the actuator according to a first or a second mode in dependence of an operational parameter, such as a torque generated by the rotation motor to rotate the drill string.

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Örebro, Sweden

Gustav Mörtzell