Steering lock

Abstract

A steering lock for locking a rotary steering member against rotation. A lockbolt is movable along a first axis between steering member-locking and -unlocking positions. A shuttle moves between a non-blocking position, in which the shuttle does not obstruct movement of the lockbolt from the steering member-locking position, and a blocking position, in which the shuttle obstructs movement of the lockbolt out of the steering member-locking position. An actuator drives the lockbolt to the steering member-locking position by moving the shuttle to the blocking position. An output gear is drivable by the actuator. A rotary drive member has a first portion formed with gear teeth meshed with the output gear, and a second portion formed with a driving structure engaged with a follower structure of the shuttle, whereby the shuttle is configured to translate axially toward and away from the first axis when the rotary drive member rotates in place.

What is claimed is: 
     
         1 . A steering lock for selectively inhibiting rotation of a rotary steering member having a rib, the steering lock comprising:
 a lockbolt movable along a first axis between a steering member-locking position, in which a distal tip of the lockbolt is positioned in interference with the rib, and a steering member-unlocking position, in which the distal tip of the lockbolt is positioned out of interference with the rib;   a shuttle movable between a non-blocking position, in which the shuttle does not obstruct movement of the lockbolt from the steering member-locking position to the steering member-unlocking position, and a blocking position, in which the shuttle obstructs movement of the lockbolt out of the steering member-locking position;   an actuator operatively coupled to the shuttle and operable to drive the lockbolt to the steering member-locking position by moving the shuttle from the non-blocking position to the blocking position;   an output gear drivable by the actuator; and   a rotary drive member having a first portion formed with gear teeth meshed with the output gear, and further having a second portion formed with a driving structure engaged with a follower structure of the shuttle whereby the shuttle is configured to translate axially toward and away from the first axis when the rotary drive member is rotated in place.   
     
     
         2 . The steering lock of  claim 1 , wherein the driving structure of the rotary drive member includes a spiral cam. 
     
     
         3 . The steering lock of  claim 2 , wherein the spiral cam includes a spiral cam groove, and the follower structure of the shuttle is positioned within the spiral cam groove. 
     
     
         4 . The steering lock of  claim 2 , wherein the spiral cam includes first and second constant radius dwell portions at radially inner and outer ends, and between the first and second dwell portions, further includes a majority portion having a radius decreasing substantially uniformly from the first dwell portion, and a minority portion having a more drastic radial decrease than the majority portion in a direction toward the second dwell portion. 
     
     
         5 . The steering lock of  claim 2 , wherein the rotary drive member rotates about a second axis parallel to the first axis. 
     
     
         6 . The steering lock of  claim 2 , further comprising a magnetic element coupled to the rotary drive member and at least one magnetic sensor positioned at a fixed location adjacent the rotary drive member. 
     
     
         7 . The steering lock of  claim 1 , wherein the driving structure of the rotary drive member includes a threaded drive portion and the shuttle includes a threaded follower structure drivably coupled to the threaded drive portion of the rotary drive member. 
     
     
         8 . The steering lock of  claim 7 , wherein the threaded drive portion of the rotary drive member is formed of an aperture with female threads and the threaded follower structure of the shuttle includes male threads. 
     
     
         9 . The steering lock of  claim 7 , wherein the rotary drive member has an outer profile including gear teeth meshed with an output gear of the actuator, the steering lock further comprising a gear set sub-housing substantially enclosing the gear teeth of the rotary drive member and the output gear. 
     
     
         10 . The steering lock of  claim 7 , wherein the shuttle includes a unitary guide body including the follower at a first end, a post portion with a slot at a second end for slidably receiving a lockbolt actuator, and a transverse flange between the first and second ends, the transverse flange having a first portion engaging a resilient bumper for defining first and second stops of the shuttle and a second portion receiving a magnetic element for position detection of the shuttle by at least one magnetic sensor positioned at a fixed location adjacent the shuttle. 
     
     
         11 . The steering lock of  claim 10 , wherein two magnetic sensors are provided on a printed circuit board fixedly positioned within a housing of the steering lock that substantially encloses the actuator and the shuttle and partially encloses the lockbolt. 
     
     
         12 . The steering lock of  claim 1 , wherein the shuttle is constrained to translate axially along a path that is substantially perpendicular to and intersecting with the first axis. 
     
     
         13 . The steering lock of  claim 1 , further comprising a lost motion connection between the actuator and the lockbolt, wherein motive force from the actuator is transmitted through the lost motion connection to drive the lockbolt to the steering member-locking position when the rib is not aligned with the first axis, and wherein motive force from the actuator is taken up by the lost motion connection when the rib is aligned with the first axis. 
     
     
         14 . The steering lock of  claim 13 , wherein the lost motion device includes a spring positioned between the follower of the shuttle and a lockbolt actuator portion of the shuttle. 
     
     
         15 . The steering lock of  claim 14 , wherein the lockbolt actuator portion of the shuttle is constrained to move along a linear path that is perpendicular to the first axis. 
     
     
         16 . The steering lock of  claim 15 , further comprising a housing enclosing the shuttle and the actuator and partially enclosing the lockbolt, wherein the lockbolt actuator portion of the shuttle is constrained to move along the linear path by at least one guide surface of the housing. 
     
     
         17 . The steering lock of  claim 14 , wherein the lockbolt actuator portion includes a shaft extending through a slot formed in a post portion of the shuttle, the shaft being biased to one end of the slot by the spring, and wherein the spring is a coil spring encircling the post portion. 
     
     
         18 . The steering lock of  claim 14 , wherein the shuttle includes first and second link members slidably coupled together, whereby one of the first and second link members is received in an opening of the other, and wherein the spring is positioned within the opening. 
     
     
         19 . The steering lock of  claim 1 , further comprising a housing enclosing the shuttle and the actuator and partially enclosing the lockbolt, wherein the follower of the shuttle is constrained to move along a linear path by at least one guide surface of the housing. 
     
     
         20 . The steering lock of  claim 1 , wherein a first inclined cam surface is provided between the shuttle and the lockbolt so that substantially linear movement of the shuttle to the blocking position in a direction substantially perpendicular to the first axis is configured to move the lockbolt to the steering member-locking position. 
     
     
         21 . The steering lock of  claim 20 , wherein a second inclined cam surface is provided between the shuttle and the lockbolt so that substantially linear movement of the shuttle to the non-blocking position in a direction substantially perpendicular to the first axis is configured to move the lockbolt to the steering member-unlocking position. 
     
     
         22 . The steering lock of  claim 1 , wherein the actuator is an electric motor. 
     
     
         23 . The steering lock of  claim 1 , wherein the lockbolt is unbiased along the first axis. 
     
     
         24 . The steering lock of  claim 1 , wherein the lockbolt is part of an integrally movable lockbolt unit that further includes a separately-formed lockbolt carrier. 
     
     
         25 . The steering lock of  claim 24 , wherein the shuttle shares a cam interface with the lockbolt carrier for moving the lockbolt to at least one of the steering member-locking position and the steering member-unlocking position. 
     
     
         26 . The steering lock of  claim 1 , wherein the second portion formed with the driving structure is positioned entirely within the first portion formed with the gear teeth.