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: A clutch or brake unit is described with an automatic wear adjustment mechanism.Clutches and brakes operate by the engagement of friction members (4,6) which experience wear in use requiring a larger stroke of the unit to effect engagement. This results in delayed clutch or brake operation which can be a serious disadvantage where prompt action is required. Conventionally this wear has been compensated by replacement of the worn friction members or by manual adjustment of them resulting in temporary disablement of the unit and requiring service personnel time.In the inventive unit, friction members (4,6) are mounted between pressure members (10,2) and an actuator (12) operates against a backing member (15) to effect clutch or brake actuation and de-activation by movement of the friction members towards and away from each other, and the position of at least one of the pressure members is adjusted automatically in response to wear of the friction members.

Abstract: A cutting or bending machine has a combined clutch and brake mechanism cooled by air flow from an electrically powered impeller. A guide duct directs the air flow substantially uniformly through the entire volume of the combined clutch and brake mechanism, preferably to the outer peripheral edges of the mechanism, so that generated heat is dissipated continuously and the machine can be operated more productively. The impeller fan and the guide duct may direct the air flow either axially or radially of the mechanism and the air flow may be either inwardly or outwardly of the mechanism.

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.

Abstract: A brake for a braking shaft has a housing containing a brake disc (20) carried by the shaft and brake assemblies comprising fluid operated actuators (31) for brake pads (30) engageable with one side of the brake disc. The actuators are mounted on a cover portion (2) which can be hinged down to facilitate servicing of the brake assemblies. The cover portion has integrally formed locating elements for the actuators and guides for the brake pads (40,41,42,44). The brake disc (20) can slide off the shaft to allow access to passive brake pads acting on the other side of the brake disc.