Abstract: A brake performance monitor has a first sensor 12 for detecting movement of a brake device to apply the brake, and a second sensor 14 for detecting a predetermined force necessary to apply the brake in normal operating conditions. If the braking force deteriorates, the brake movement is detected before the predetermined force is reached, and an output device 10 signals the fault, for example by halting the machinery 4 being braked.

Abstract: A brake device includes actuators (31) for brake pads (30), which can be pneumatically powered to which urge the brake pads (30) into engagement with a brake disc (20). The actuators (31) are mounted on a front housing portion (2) which is pivotable on a rear housing portion (4) to open the housing and allow access to the actuators (31), as for servicing. Opening the housing causes a normally closed orifice (49) in the compressed air supply line to be opened, relieving pressure on the actuators (31), and protecting them from damage.

Abstract: A motor-driven drive shaft is coupled to a grinding mill or other unbalanced rotatable member through a clutch arranged to accommodate misalignment, the clutch being so controlled during start-up as to be initially engaged to effect a first limited rotation of the mill in the drive direction, then disengaged to permit the mill to rotate under its own weight through a second rotation in the direction reverse to the drive direction and through a third rotation in the drive direction, and then to be re-engaged during the second rotation of the member in the drive direction. Clutch orbiting is thus reduced if not eliminated.

Abstract: The supply of a pressure fluid to one or more outlets additional to a permanent outlet is controlled by the provision for the or each additional outlet of a pressure fluid circuit including sources of higher and lower reference pressure fluids and three comparator valves using the reference pressure fluids and the pressure fluid to connect the pressure fluid to the additional outlet when the pressure fluid pressure exceeds the higher reference pressure and to disconnect the pressure fluid from the additional outlet when the pressure fluid pressure falls below the lower reference pressure.