Abstract: The disclosure relates to improvements in the measurement of shaft speed. The shaft has an end face and at least one detection mark provided on or in the end face of the shaft to enable the speed, angular displacement, position or movement of the shaft to be detected. The shaft is for use in a shaft assembly comprising a sensor positioned at a distance from the shaft end face. The sensor is configured to measure the speed, angular displacement, position or movement of the shaft by sensing movement of the detection marks.

Abstract: A gearbox hydraulic circuit includes a hydraulic pump connected to a fluid reservoir to generate a flow of pressurised fluid. A pressure circuit connected to the hydraulic pump conveys the flow of pressurised fluid. A pressure control valve disposed in the pressure circuit between the first line and the second line of the pressure circuit maintains the pressure of the pressurised fluid in the first line. A shunt connected to the pressure circuit is operable to route the flow of pressurised fluid from the first line to the second line to reduce the pressure in the first line.

Abstract: The disclosure relates to improvements in the measurement of shaft speed. The shaft has an end face and at least one detection mark provided on or in the end face of the shaft to enable the speed, angular displacement, position or movement of the shaft to be detected. The shaft is for use in a shaft assembly comprising a sensor positioned at a distance from the shaft end face. The sensor is configured to measure the speed, angular displacement, position or movement of the shaft by sensing movement of the detection marks.