Automotive vehicle steering column lock mechanism

An automotive vehicle steering column lock assembly is disclosed for use with a steering wheel connected to a steering column passing through a steering column housing to which an ignition switch is mounted. The assembly has a lock ring adapted to be mounted to the steering column and having at least one lock recess on an end thereof and a lock pawl movable between a lock position engaged in the lock recess and an unlock position disengaged from the at least one lock recess. A tray is adapted for slidable movement within the steering column housing generally parallel to the steering column, the tray having a lock pawl bed allowing the lock pawl to slide therein generally parallel to the steering column. Tray control means operatively connecting the ignition switch and the tray move the tray between at least two positions in which the lock pawl alternately engages and disengages the lock ring to prevent and allow, respectively, rotation of the steering column. A lock lever, fixed with respect to the steering column housing, is movable between a blocking position preventing the lock pawl from moving into the at least one lock recess on the lock ring, and an unblocking position allowing the lock pawl to enter the at least one lock recess. To control operation of the lock lever relative to a key inserted state of the ignition switch, a control lever operatively connects the ignition switch with the lock lever and is moveable between a release position when a key is inserted into the ignition switch allowing the lock lever to move to the block position, and a depress position when the key is removed from the ignition switch forcing the lock lever to an unblock position to allow the lock pawl to move to the locked position.

FIELD OF THE INVENTION 
The present invention relates to automotive steering columns in general, 
and more specifically to steering column lock mechanisms. 
BACKGROUND OF THE INVENTION 
It is known to provide a lock mechanism for an automotive vehicle steering 
column to prevent rotation of the steering wheel under certain 
circumstances, for example, to deter to vehicle theft when not in use. 
Various steering column lock mechanism have been disclosed which use an 
ignition switch actuated rack and pinion drive to prevent rotation of a 
steering column. Early examples of such devices include the mechanisms 
disclosed in U.S. Pat. No. 1,400,507 (Addis) and U.S. Pat. No. 1,487,863 
(Lavigne), which use the rack of a rack-and-pinion drive to act directly 
on the steering column to prevent steering column rotation. A more recent 
example of steering column lock technology is shown in U.S. Pat. No. 
5,265,487 (Williams et al.), assigned to the assignee of the present 
invention, which uses a steering wheel mounted ignition to reciprocate a 
rack by a pinion connected to a key cylinder. Another steering column 
locking device, disclosed in U.S. Pat. No. 5,172,576 (Milton), rotates a 
pinion by a steering column support ignition to actuate a rack. A second 
rack attached to the first rack rotates a control gear which, in turn, 
actuates a clutch connected to the steering column. 
SUMMARY OF THE INVENTION 
The present invention is a new and improved steering column lock assembly 
which provides steering column shaft locking upon key removal with the 
ignition switch in the lock position. The steering column lock assembly is 
typically used for an automotive vehicle having a steering wheel connected 
to a steering column passing through a steering column housing to which an 
ignition switch is mounted. The assembly has a lock ring adapted to be 
mounted to the steering column and having at least one lock recess on an 
end thereof and a lock pawl movable between a lock position engaged in the 
lock recess and an unlock position disengaged from the at least one lock 
recess. A tray is adapted for slidable movement within the steering column 
housing generally parallel to the steering column, the tray having a lock 
pawl bed allowing the lock pawl to slide therein generally parallel to the 
steering column. Tray control means operatively connecting the ignition 
switch and the tray move the tray between at least two positions in which 
the lock pawl alternately engages and disengages the lock ring to prevent 
and allow, respectively, rotation of the steering column. A lock lever, 
fixed with respect to the steering column housing, is movable between a 
blocking position preventing the lock pawl from moving into the at least 
one lock recess on the lock ring, and an unblocking position allowing the 
lock pawl to enter the at least one lock recess. To control operation of 
the lock lever relative to a key inserted state of the ignition switch, a 
control lever operatively connects the ignition switch with the lock lever 
and is moveable between a release position when a key is inserted into the 
ignition switch allowing the lock lever to move to the block position, and 
a depress position when the key is removed from the ignition switch 
forcing the lock lever to an unblock position to allow the lock pawl to 
move to the locked position. 
An advantage of the present invention is steering column lock assembly 
which provides positive containment of a steering column lock pawl. 
Another advantage is a steering column lock assembly which prevents shaft 
locking with a key inserted into the ignition switch regardless of switch 
position. 
Still another advantage of the present invention is a steering column lock 
assembly in which the steering column shaft is locked when a key is 
removed from the ignition switch by disengaging positive containment of 
the lock pawl. 
A feature of the present invention is a pair of levers pivotally mounted to 
the steering column housing for providing positive containment of the lock 
pawl relative to a key inserted or removed state of the ignition switch.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Turning now to the drawings, and in particular to FIG. 1 thereof, an 
automotive steering wheel assembly 10 is shown having a steering wheel 12 
connected to a steering column 14. The steering column 14 passes through a 
steering column housing 16, which is shown partially cut away for 
illustrating passage of the steering column 14 therethrought. Attached to 
the steering column housing 16 is an ignition switch assembly 18, which is 
commonly done in automotive vehicles. 
Referring now to FIG. 2, a steering column lock assembly according to the 
present invention is shown in a perspective view. As those skilled in the 
art understand, and as described above, it is desirable to provide a 
steering column lock mechanism in an automobile to deter vehicle thief by 
preventing steering control when a key is removed from the ignition 
switch. As best seen in FIG. 4A, a lock ring 20 is mounted to the steering 
column 14 for rotatable movement therewith. The lock ring 20 has at least 
one lock recess 22 on an end face 24. 
There can be, however, two or more lock ring recesses, as seen in FIG. 4A. 
As seen in FIG. 2, a tray 26 is mounted for slidable movement within the 
steering column housing 16 between several positions generally parallel to 
a steering column axis 28. The tray 26 may slide in a tract 30 which may 
be formed as part of the steering column housing 16 (FIG. 2). The tray 26 
has a lock pawl 32 slidably disposed in a lock pawl bed 34 for movement 
generally parallel to the steering column axis 28. In a preferred 
embodiment of the present invention, the lock pawl 32 has a lock recess 
engaging member 36 substantially perpendicular to a lock pawl bed sliding 
member 38 (FIGS. 2 and 4C). The lock pawl 32 is bias toward a stop member 
40 at a first end 42 of the tray 26 by a coil spring 44 (FIGS. 2, 4A, and 
4B). The coil spring 44 is mounted around a spring post 46 extending from 
a second end 48 of the tray 26 and is received in a spring recess 50 on a 
spring post facing surface 52 of the lock pawl 32 (FIGS. 2, 4A and 4B). 
The lock pawl 32, although carried with the tray 26, can slide relative 
thereto in the lock pawl bed 34. 
The tray 26 has a rack of teeth 54 along a bottom edge 56 (FIG. 4A). The 
teeth 54 engage an ignition switch gear 58 mounted around an ignition 
actuator rod 60 (FIG. 4C) so that rotation of the rod 60 by a key 62 
inserted into the ignition switch 18 (FIG. 2) rotates the gear 58 thus 
converting rotational motion of the ignition switch into translational 
motion of the tray 26 end rack-and-pinion fashion (FIGS. 2, 4A-4C). 
Also connected around the ignition switch actuator rod 60 is a collar 62 
having an annular groove 64 circumferentially therearound (FIGS. 4B and 
4C). As best seen in FIGS. 4B and 5B, the collar 62 is moveable axially 
along the longitudinally axis 66 of the rod 60 between a key removed state 
(FIG. 4B) and which the rod 60, and thus the collar 62, is biased away 
from the tray 26 by a ignition switch spring 68, and a key inserted state 
(FIG. 5B) in which the rod 60 and thus the collar 62, are moved toward the 
tray 26 to overcome the bias force of the spring 68 by insertion of a key 
(not shown) into the ignition switch 18. 
Operatively connected with the collar 62 is a steering column lock actuator 
lever 70 (FIGS. 4A, 4B, 4D and 5D) which has a upwardly extending tab 72 
on a first end 74 for engagement with the groove 64 of the collar 62. The 
steering column lock actuator lever 70 is mounted to the housing with a 
screw 76 for substantially planer movement in a plane parallel to lock 
pawl bed 34 (FIG. 4B). Movement of the collar 62 in response to insertion 
of a key into the ignition switch 18 between the key removed state (FIG. 
4D) and the key inserted state (FIG. 5D) moves the tab 72 on end 74, thus 
pivoting the steering column lock actuator lever 70 so as to move end 78 
between a lock actuator lever de-prepositions (FIGS. 4A-4D) in which the 
end 78 of the steering column lock actuator lever 70 depresses a contact 
tab 80 of a steering column lock lever 82, and a lock actuator lever 
release position (FIGS. 5A-5D) in which the end 78 of the steering column 
lock lever 70 is released from the depressed position. 
The steering column lock lever 82 is pivotally mounted to a portion of the 
housing 16 for planer movement substantially perpendicular to the steering 
column axis 28, and substantially perpendicular to movement of the 
steering column lock actuator lever 70 planer movement (FIGS. 2 and 4B). A 
torsional spring 84 biases the lock lever 82 to a pawl lock position 
(FIGS. 5A-5D) in which an end 86 of the lock actuator lever extends toward 
the stop 40 of the lock pawl bed 34 (FIGS. 5B and 5D) so as to contact an 
edge face 88 of the lock pawl 32 (FIGS. 2 and 5B-5D) so as to prevent 
movement of the lock pawl 32 into engagement with the recesses 22 of the 
lock ring 20, as further described below. 
In operation, the steering column lock assembly of the present invention 
prevents the steering column from locking until the key has been removed 
from the ignition switch. As seen in FIG. 3, the ignition switch 18 can be 
rotated between 4 positions with a key inserted therein, including a key 
removal position, an off position, a run position, and a start position. 
With the key removed from the ignition switch 18, the steering column lock 
assembly is in the position of FIGS. 4A-4D, 4D, thus locking the steering 
column 14 from rotation and preventing the steering wheel from being 
turned. In the steering column lock position, the lock pawl 32 is engaged 
with a lock recess 22 (FIG. 4A). Since the key is removed from the 
ignition switch 18, the collar 62 moves the tab 72 away from the steering 
column axis 28 (FIG. 4B) so that the steering column lock actuator lever 
70 is in a depressed position against the tab 80 of the lock lever 82 
overcoming the bias of spring 84 so as to rotate the lever 82 out of the 
path of the lock pawl 32. The tray 26 is in a left most position (FIG. 4A) 
with the lock pawl 32 abutting the stop 40 under the bias of spring 44 to 
engage the lock recess 22. 
When a key is inserted into the ignition switch 18 (FIG. 5D), the collar 62 
moves the tab 72 toward the axis 28 thus pivoting the steering column lock 
actuator lever 70 to an undepressed position allowing the steering column 
lock lever 82 to pivot so that end 86 can obstruct the path of lock pawl 
32. In the start position (FIGS. 5A-5D), the tray 26 has been translated 
toward the right end FIG. 5A due to rotation of the ignition switch 18 and 
interaction of the pinion 58 with the rack 54 (FIGS. 5A-5C). During this 
translation of the tray 26, the lock pawl 32 disengages from the lock 
recess 22 of the lock ring 20 (FIGS. 5A and 5B). When the lock pawl 32 has 
moved pass the steering column lock lever 82, the lever 82 moves into the 
path of the lock pawl 32 under the bias of spring 84 (FIGS. 5A-5D). The 
lock pawl 32 is thus blocked by the steering column actuator lever 82 from 
reengaging the lock ring 20 so that the steering column 14 is unlocked and 
free to rotate. 
Upon rotation of the ignition switch 18 from the off position to the run 
position (FIG. 3), the tray 26 is furthered translated toward the right 
(FIG. 6A) thus leaving a space between the steering column lock lever 82 
and the lock pawl 32 (FIGS. 6A and 6B). As the ignition switch is rotated 
to the start position (FIG. 3), the tray 26 is translated, through the 
rack and pinion motion of the teeth 54 and gear 58, respectively, to a 
right most position (FIG. 7A) in which a larger gap 90 opens between the 
pawl 32 and the steering column lock lever 82 (FIGS. 7A and 7B). The 
steering column lock lever 82 remains biased toward a blocking position to 
prevent the lock pawl 32 from reengaging the lock ring 20, and thus the 
steering column 14 is free to rotate (FIG. 7A). 
During typical driving operation of an automotive vehicle, the ignition 
switch is in a run position (FIG. 3), and in the steering column lock 
assembly according to the present invention the tray 26 and lock pawl 32 
are in the position shown in FIGS. 6A and 6B disengaged from the lock ring 
20 to allow free rotation of the steering column 14. The lock pawl 32 is 
prevented from engaging the recess 22 of the lock ring 20 by the stop 40 
of the lock pawl bed 34, which is dictated by the position of the tray 26 
(FIG. 6A). Should the tray 26, and thus the lock pawl 32 move to the left 
(FIG. 6) when the ignition switch 18 is in the run position, the steering 
column lock lever 82 will block the lock pawl 32 from engaging the lock 
recess 22 in the lock ring 20, thus preventing steering column 14 lock up. 
When the ignition switch 18 is rotated from the run position FIG. 3) to the 
key removal position, as typically occurs after operation of a vehicle is 
completed and a vehicle driver is leaving the vehicle, the tray 26 is 
rotated to the left most position (FIG. 8A), but the steering column lock 
lever 82 locks the lock pawl 32 from leftward movement (FIG. 8A), so that 
the lock pawl 32 slides in the lock pawl bed 34 relative to the tray 26 
and compressing the spring 44. When the key is removed from the ignition 
switch 18, the steering column lock assembly of the present invention 
returns to the locked state of FIGS. 4A-4D, by outward movement of the 
collar 62 moving the tab 72 to rotate the lever 70 to the depressed 
position against member 80 of the steering column lock lever 82, thus 
rotating the lock lever 82 to an unblocking position (FIGS. 4B-4D) so that 
the lock pawl 32 is forced to the lock recess 22 of the lock ring 20 under 
the bias of spring 44 (FIG. 4A). 
The present invention thus provides a steering column lock assembly which 
prevents a steering column from locking, after a key has been inserted 
into the ignition switch, until the key is removed from the ignition 
switch. 
Although the preferred embodiment of the present invention has been 
disclosed, various changes and modifications may be made without departing 
from the scope of the invention as set forth in the appended claims.