Patent ID: 8567713

Claim:
An apparatus comprising: a lift fan clutch operable to modulate power between an aircraft powerplant and a vertical lift fan, the lift fan clutch having: a first inner plate slidingly coupled to a first shaft a second inner plate slidingly coupled to the first shaft independently of the first inner plate; a first outer plate and a second outer plate slidingly coupled with a second shaft, the first inner plate located between the first outer plate and the second outer plate, the first outer plate located between the first inner plate and the second inner plate; wherein the plates are operable to be placed in contact in an engaged state and operable to be separated in a disengaged state, the first outer plate and second outer plate operable to be moved relative to one another; a first inner energy storage device having a first portion coupled with the first inner plate such that the first portion is stationary with respect to the first inner plate and a second portion coupled with the first shaft such that the second portion is stationary with respect to the first shaft, and such that the first inner energy storage device provides a force that opposes relative motion between the first inner plate and the first shaft, wherein the first inner energy storage device is operable to return the first inner plate to a first inner plate disengaged position when in the disengaged state; a second inner energy storage device having a first portion coupled with the second inner plate such that the first portion is stationary with respect to the second inner plate and a second portion coupled with the first shaft such that the second portion is stationary with respect to the first shaft, and such that the second inner energy storage device provides a force that opposes relative motion between the second inner plate and the first shaft, wherein the second inner energy storage device is operable to return the second inner plate to a second inner plate disengaged position when in the disengaged state; an outer energy storage device connected between the first outer plate and the second outer plate such that the outer energy storage device provides a force that opposes relative motion between the first outer plate and the second outer plate, wherein the outer energy storage device is operable to provide a force to urge the first outer plate apart from the second outer plate when in the engaged state; and wherein the engaged state is operable to couple rotation of the first shaft and the second shaft.