An apparatus, rock drilling rig and method for rock drilling includes a turning device for moving a drilling tool around longitudinal axis of the tool. The turning movement is controlled by an alternating turning system so that direction of turning movement is continuously reversed to first and second turning directions. The turning angle of the tool is restricted and a safety system (is configured to monitor the operation and to ensure that a predetermined turning angle is not exceeded.

An apparatus, rock drilling rig and method for rock drilling includes a turning device for moving a drilling tool around longitudinal axis of the tool. The turning movement is controlled by an alternating turning system so that direction of turning movement is continuously reversed to first and second turning directions. The turning angle of the tool is restricted and a safety system (is configured to monitor the operation and to ensure that a predetermined turning angle is not exceeded.

A method may include communicating a command into a wellbore from the surface. The method may include determining a command to be sent to a downhole tool, and translating the command into a message, the message including a sequence of codes. The method may include rotating the drill string substantially at the set point RPM for a predetermined duration and measuring the rotation rate of the drill string. The method may include identifying the received set point RPM and rotating the drill string consistent with a first code value of a first code of the message as encoded. The method may also include decoding the first code and rotating the drill string consistent with a second code value of a second code of the message as encoded. The method may also include decoding the second code, identifying the command from at least one of the decoded first and second code and executing the command.

A method may include communicating a command into a wellbore from the surface. The method may include determining a command to be sent to a downhole tool, and translating the command into a message, the message including a sequence of codes. The method may include rotating the drill string substantially at the set point RPM for a predetermined duration and measuring the rotation rate of the drill string. The method may include identifying the received set point RPM and rotating the drill string consistent with a first code value of a first code of the message as encoded. The method may also include decoding the first code and rotating the drill string consistent with a second code value of a second code of the message as encoded. The method may also include decoding the second code, identifying the command from at least one of the decoded first and second code and executing the command.

An apparatus, rock drilling rig and method for rock drilling includes a turning device for moving a drilling tool around longitudinal axis of the tool. The turning movement is controlled by an alternating turning system so that direction of turning movement is continuously reversed to first and second turning directions. The turning angle of the tool is restricted and a safety system (is configured to monitor the operation and to ensure that a predetermined turning angle is not exceeded.

Systems and methods determine friction in a borehole during drilling operations. A drilling system applies oscillatory angular movement at the top of a drill string in a wellbore during drilling by the drilling system, and measures a torque applied to the drill string and an angular position of the drill string. Based on the measured torque and the measured angular position, the drilling system computes a friction between the borehole and the drill string. This can be repeated during drilling of the wellbore to determine multiple friction values, corresponding to various depths of the borehole. Based on the computed friction, the drilling system can perform one or more actions resulting in modified drilling operation. The systems and methods also include oscillating a casing in the borehole, measuring the torque and angular position of the casing, and determining a friction value, which can be repeated to develop a wellbore friction profile.

Systems and methods determine friction in a borehole during drilling operations. A drilling system applies movement of a drill string located in a wellbore during drilling of the wellbore by the drilling system, and, using information from one or more surface and/or downhole sensors, the drilling system determines a friction between the borehole and the drill string. This can be repeated during drilling of the wellbore to determine multiple friction values, which can correspond to various depths of the borehole and/or the length of the drill string. Based on the determined friction values, the drilling system can generate a friction profile of the wellbore and can perform one or more actions resulting in modified drilling operations. The systems and methods also include oscillating a casing in the borehole, measuring the torque and angular position of the casing, and determining a friction value, which can be repeated to develop a wellbore friction profile.

An apparatus for drilling a hole in a golf green. The apparatus includes a support frame, a moveable cutter head, a handle, a base, a tread plate, an ejection mechanism, a drive motor configured to power the operation of the apparatus and control device. A drive shaft connects the drive motor with the cutter head via a threaded coupling. The cutter head is advanced relative to the tread plate when the drive shaft is rotated in one rotational direction and is retracted relative to the tread plate when the drive shaft is rotated in the opposite rotational direction. The drive shaft is provided with a central threaded portion and a non-threaded end portion at each end of the thread. The non-threaded end portions act as slip couplings configured to allow a rotation of the drive shaft without axial movement of the threaded coupling to stop the cutter head.