US Patent 7798279 Steer-by-wire steering apparatus with actuatable mechanism

A steering apparatus (10) for turning steerable wheels of a vehicle in response to rotation of a vehicle steering wheel (12) comprises a first assembly (16), a second assembly (26), and a mechanism (108). The first assembly is operatively coupled to the steering wheel and includes components (18, 22) for monitoring applied torque and angular rotation of the steering wheel. The second assembly includes a steering gear (34) and components (28, 30) for actuating the steering gear in response to the monitored rotation. The mechanism, when in a first mode of operation provides a mechanical connection between the steering wheel and the steering gear. The mechanism when in the second mode of operation, providing a mechanical connection between the steering wheel and the steering gear sufficient to enable manual actuation of the steering gear and permit actuation of the steering gear in response to the monitored steering wheel rotation.