Patent ID: 8245827

Claim:
An apparatus for transmitting force to rotate a shaft and for transmitting force to retain the shaft against rotation, said apparatus comprising a base member having a central opening which receives the shaft, a clutch surface which is disposed adjacent to said base member and is movable relative to said base member, said clutch surface being connected with a source of driving force to be transmitted to the shaft, a brake surface which is disposed adjacent to said base member and is movable relative to said base member, said brake surface being connected with a stationary member, a piston which is connected with said base member and is movable in first and second directions relative to said base member, said piston being movable in one of the first and second directions under the influence of fluid pressure applied to said piston from a variable volume annular fluid chamber to press a first friction surface against said clutch surface to transmit force between said clutch surface and said base member, said piston being movable in another of the first and second directions to press a second friction surface against said brake surface to transmit force between said brake surface and said base member, a plurality of force transmitting members which extend between said piston and said base member and transmit force between said piston and said base member, a plurality of springs which urge said piston to move in the other of said first and second directions relative to said base member, and a plurality of spaced apart spring retainers disposed between said base member and said piston, each of said spring retainers having a base portion and a plurality of projecting portions extending from said base portion, each of said springs being telescopically disposed on one of said projecting portions of said spring retainers to locate said springs relative to said base member, each of said force transmitting members being disposed between adjacent spring retainers of said plurality of spring retainers, said plurality of projecting portions extending from said base portion of each of said spring retainers includes a first series of projections which are disposed in an arcuate inner array having a first radius of curvature and a second series of projections which are disposed in an arcuate outer array having a second radius of curvature which is larger than said first radius of curvature, said plurality of force transmitting members are disposed in an arcuate array having a radius of curvature which is larger than said first radius of curvature, each of said plurality of force transmitting members has a diameter that decreases in size with one end received within said base member, each of said force transmitting members having a shoulder that abuts and is supported by the base member for providing a resistance to moment load.