Abstract: A force transmitting assembly is operable between a plurality of engaged conditions and a disengaged condition in which the force transmitting assembly is ineffective to transmit force. The force transmitting assembly includes a primary piston assembly having annular radially inner and outer piston areas against which fluid pressure is applied to vary the magnitude of the force which can be transmitted by the force transmitting assembly. The force transmitting assembly also includes a secondary piston assembly having radially inner and outer piston areas against which fluid pressure is applied to vary the magnitude of the force which can be transmitted by the force transmitting assembly. In one embodiment of the invention, the secondary piston assembly includes two separate pistons. In another embodiment of the embodiment of the invention, the secondary piston assembly includes a single piston having annular radially inner, radially outer, and intermediate piston areas against which fluid pressure is applied.

Abstract: An improved force transmitting apparatus for transmitting force between first and second members includes a plurality of force transmitting assemblies. The force transmitting assemblies are operable between engaged conditions in which the first force transmitting apparatus is effective to transmit force and disengaged conditions in which the force transmitting apparatus is ineffective to transmit force. A controller operates the force transmitting assemblies between the disengaged and engaged conditions as a function of a load applied to the apparatus. The improved force transmitting apparatus is useful as a brake in a drilling system having a draw string connectable with pipe. The force transmitting assemblies are connected with a drum of a winch connected to the draw string.

Abstract: An improved force transmitting assembly includes a pair of force transmitting discs and a reaction disc which is disposed between the force transmitting discs. When the force transmitting assembly is in a disengaged condition, a spacer assembly maintains the force transmitting discs spaced apart by a distance which is greater than the distance between opposite side surfaces of the reaction disc. A locator assembly moves the force transmitting discs to predetermined positions whenever the force transmitting assembly is operated from the engaged condition to the disengaged condition. As the force transmitting assembly is disengaged, the locator assembly pulls one force transmitting disc to a predetermined position. Since the spacer assembly maintains a predetermined space between the two force transmitting discs, the other force transmitting disc is also moved to a predetermined position as the locator assembly pulls the one force transmitting disc to a predetermined position.

Abstract: A disc brake or clutch unit (10) comprising a rotor disc (12) having a fixed reaction member (21,23) on each side of the rotor disc (12) with the reaction members fixed in axially spaced relationship by connecting members (24,25) extending axially in position radially outwardly from the rotor disc. A pair of moveable reaction members (27,28) positioned between each side of the rotor disc (12) and one of the second fixed reaction members with the relatively moveable annular reaction members connected to each other a fixed axial distance apart by connecting members (29,30) extending axially and positioned radially outwardly from the rotor disc (12). Springs (35) are positioned between a first axially moveable reaction member (27) and a relatively fixed reaction member (23) for biasing the moveable reaction member (27) into fictional engagement with the disc (12).

Abstract: A disc brake or clutch assembly having rotatable rotor discs and non-rotatable discs which are movable axially into engagement. The rotatable rotor discs are secured to an annular splined mounting member which has a plurality of grooves therein to circulate cooling air. The rotor discs have a plurality of holes which enable air to flow between the rotor discs.