Abstract: A steering column locking mechanism 130 includes a piston 176 located in a chamber in a housing 178. The locking mechanism 130 is in an engaged condition locking the steering column 10 against movement relative to a frame of a vehicle when the piston 176 is in a first position (FIG. 2). The locking mechanism 130 is in a disengaged condition in which the locking mechanism is ineffective to lock the steering column 10 when the piston is in a second position (FIG. 3). The first pressure is continuously applied to a relatively small area on a first side 256 of the piston 176 to retain the piston in the first position and to retain the locking mechanism 130 in the engaged condition. Pressure is applied to a relatively large area on a second side 272 of the piston 176 to move the piston from the first position to the second position against the influence of the first pressure.

Abstract: An apparatus (10) for turning the steerable wheels (17) of a vehicle in response to the turning of the steering wheel (12). The apparatus (10) includes a drive mechanism (16), a first motor (24), a second motor (74), a sensor (78) for sensing that the first motor (24) is inoperative, and a torque sensor (80). In response to the turning of the steering wheel (12), the drive mechanism (16), is actuated, resulting in a turning the steerable wheels (17). The first motor (24), for inputting motion to the drive mechanism (16), is hydraulically powered. The second motor (74), for inputting motion to the drive mechanism (16), is electrically powered. The sensor (78) for sensing that the first motor (24) is inoperative produces an enabling signal and communicates the enabling signal to the second motor (74) to enable the operation of the second motor (74). The torque sensor (80) responds to the turning of the steering wheel (12) and controls the second motor (74) when the second motor (74) is enabled.

Abstract: A steering apparatus (10) for use in a vehicle (12) having a steerable road wheel (14) includes a steering member (30) supporting the road wheel for rotation relative to the steering member. A vehicle suspension part (22) supports the steering member (30) for pivotal movement about a steering axis (42). The vehicle suspension part (22) has a housing portion (26) defining a chamber (50). A piston (52) is located in the chamber (50) and divides the chamber into first and second chamber portions (56, 58). The piston (52) is movable in response to changes in fluid pressure in the chamber portions (56, 58). An output shaft (90) is rotatable in opposite directions in response to movement of the piston (52) in opposite directions. The output shaft (90) is connected to the steering member (30) to pivot the steering member about the steering axis (42) upon rotation of the output shaft.