Abstract: A brake system includes a brake disc having a first disc face and a second disc face on a first side and a second side, respectively, of the brake disc. The brake disc is mounted rotatably fast with but longitudinally slidable on a rotatable shaft. The brake disc is clampable between a first friction surface of a fixed brake pad positioned on the first side of the brake disc and a second friction surface of a moveable brake pad positioned on the second side of the brake disc. The system further includes a disc positioner operable to define a running clearance between the first disc face and the first friction surface. The disc positioner is adjustable to maintain the running clearance as the fixed brake pad wears. A biasing member located on the second side of the brake disc maintains contact between the disc positioner and first disc face of the brake disc.

Abstract: An apparatus for actuating a brake comprising force transmission means for transmitting force to a friction pad of a brake, at least one piezo-electric device operable when energised to change shape and/or size so as to apply a force to the force transmission means in a direction for actuating the brake, and retaining means operable to resist movement of the force transmission means in an opposite direction

Abstract: A brake actuating apparatus includes a force transmission element operable to transmit a brake actuating force and an abutment member moveable to abut the force transmission element. A piezo-electric device operable on expansion applies a force between the abutment member and the force transmission element to move the force transmission element in a direction of brake actuation. A support member moveable independently of the abutment member supports the force transmission element in the new position following expansion of the piezo-electric device.