Steering column lock for motor vehicles

A motor vehicle steering column lock includes a drove rod element extending axially along a bore within the housing of the steering column lock for actuating a steering column locking bolt member in accordance with known steering column lock mechanisms. The drive rod element of the steering column lock is provided with a radial projection that cooperates with a radial wall of an enlarged recess of the bore extending through the lock housing for preventing axial withdrawal of the drive rod element from the housing and also includes an axial locking projection that is spring biased into a locking recess for preventing relative rotation between the drive rod element and the housing when the steering column lock is transported or stored without a lock cylinder installed in the housing.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention concerns a steering column lock for motor vehicles. 
2. Discussion of Related Technology 
Motor vehicle steering column locks are known and have been described in 
the patent literature (see, for example, German Patent No. 25 01 245 
A1-FIG. 9). In such steering column locks, the steering shaft locking 
member consists of a locking bolt movable from inside the steering column 
lock housing and which is displaceable transversely relative to the 
steering column lock drive mechanism to lock the steering column (i.e., 
the stearing shaft thereof) in response to a spring-biasing force that 
normally biases the locking bolt towards the locked position. The locking 
bolt may be driven out of the locked position by the steering column lock 
drive element which urges the locking bolt against its spring biasing 
force and holds it in an unlocked position when the steering shaft of the 
steering column is unlocked. 
To secure the lock drive element of the steering column lock in the 
steering column lock housing when the key lock cylinder is not assembled 
to the lock mechanism, the lock drive element is provided with a radial 
projection that may be rotated inside the steering column lock housing and 
within an inner enlarged annular recess into a position whereat the 
projection is spaced from an inner axial channel of the steering column 
lock housing accommodating the projection during assembly of the lock 
drive element in the housing and where at the projection is located such 
that the projection interferes with axial movement of the lock drive 
element out of the housing. The lock drive element is normally held in 
this rotated position by the steering shaft locking bolt which is 
spring-loaded against the lock drive element. 
However, apart from the force of the spring-loaded steering shaft locking 
bolt against the lock drive element, there is no other mechanism provided 
to prevent inadvertent rotation of the lock drive element into a position 
whereat it may be escape from the interior of the steering column lock 
housing when a key lock cylinder is not secured in the housing. 
BRIEF SUMMARY OF THE INVENTION 
The object of this invention is to provide a steering column lock for motor 
vehicles wherein the lock drive element for the steering shaft locking 
bolt is fixed against angular rotation as well as axial displacement in 
the steering column lock housing even when a key lock cylinder is not 
provided in the housing. 
In accordance with the invention, a motor vehicle steering column lock is 
provided that cooperates with a steering shaft locking member or bolt, the 
steering column lock comprising a housing including an axial bore, an 
ignition switch receiving area at one end of the bore and a lock cylinder 
receiving area at the other end of the bore, with the lock cylinder 
receiving area forming an extension of the axial bore. A peripheral 
annular enlarged recess is provided along the bore, the annular recess 
including a radial wall on one side thereof that is located away from the 
ignition switch receiving area of the housing. An axial channel is 
provided extending along a side wall area of the bore that extends 
generally from the lock cylinder receiving area of the housing to the 
annular enlarged recess, with the channel intersecting the recess at the 
aforesaid radial wall. 
A locking projection engaging recess is provided in the bore intersecting 
the radial wall of the enlarged annular recess at a point 
circumferentially spaced from the intersection of the channel with the 
radial wall, preferably 180.degree. apart. A lock drive rod element is 
supported in the bore for axial and rotational motion and includes a 
radial projection projecting radially into the enlarged annular recess. 
The axially extending channel has a width sufficient to accommodate axial 
passage of the projection along the bore when the lock drive rod element 
is axially inserted into the bore from the lock cylinder receiving end 
thereof. However, the radial projection, once it is rotated out of 
registration with the channel, is restrained from axial motion beyond said 
radial wall of the enlarged annular recess in the direction of the lock 
cylinder receiving end of the housing by interference between the radial 
wall and the radial projection. An axially extending locking projection is 
associated with the radial projection and engages the locking projection 
engaging recess in the radial wall of the enlarged annular recess when the 
radial projection is rotated to align the locking projection with the 
recess. A spring element is provided for biasing the lock drive rod 
element away from the ignition switch receiving area of the housing 
towards the key lock cylinder receiving end thereof and this spring 
element urges the locking projection into engagement with the locking 
projection receiving recess when the locking projection is rotated into a 
position such that it is in alignment with the recess. 
In this position, the lock drive rod element is restrained against axial 
motion out of the axial bore of the steering column lock housing and is 
also restrained against rotation into a position where the radial 
projection will fall into alignment with the axial channel intersecting 
the radial wall of the enlarged annular recess. 
Insertion of a lock cylinder into the steering column lock housing 
disengages the locking projection from its recess and permits rotation of 
the lock drive rod element by a key inserted into the rotatable core of 
the lock cylinder in a normal manner to be positioned in several 
conditions that are known in the field of steering column locks.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The motor vehicle steering column lock in accordance with the invention 
comprises a housing 1, a drive rod element 2, a lock cylinder 3, an 
electric ignition starter switch 4 and a steering shaft locking bolt 
member (not shown) that cooperates with the drive rod element 2 for 
locking a motor vehicle steering shaft against rotation. 
The ignition starter switch 4 is received in and fixed within an enlarged 
end section 5 of the steering column lock housing 1 and the lock cylinder 
3 is received and mounted in a lock cylinder receiving end of the bore 
hole 6 of the housing opposite the end of the housing that receives the 
ignition switch. The drive rod element 2 is mounted in the housing 1 
between the lock cylinder 3 and the ignition starter switch 4. 
The drive rod element 2 controls the displacement of the steering column 
locking bolt member between a locked position and unlocked position by 
means of a cam 7 on the rod and the rod element 2 actuates the ignition 
starter switch 4 by means of a drive shaft portion 8 which at its free end 
9 engages the ignition starter switch 4. The drive rod element 2 is 
rotatable within the housing 1 and rests therein in an axially 
displaceable manner, being biased by a helical compression coil spring 10 
toward the end of the housing holding the lock cylinder 3. The spring 10 
also biases the lock cylinder core 14 of the lock cylinder 3. The helical 
spring 10 is fitted around the shaft portion 8 and engages an annular 
shoulder 11 of the shaft portion 8 at one end and an annular shoulder 12 
of the steering column lock housing 1 at its other end. 
The lock cylinder 3 includes an outer cylinder housing 13 and an inner core 
14 that is rotatable by a removable key 18, such rotation also causing 
axial displacement of the core 14 in a manner that will be explained 
below. The housing 13 is detachably secured in the steering column lock 
housing 1 by an axially (relative to the pin itself) displaceable radially 
extending detent pin 16 biased by a helical compression spring 15, the pin 
16 entering a radial bore hole 17 of the steering column lock housing 1. 
When the core 14 is rotated by the key 18 within the housing 13, the core 
is axially displaceable and, by means of a non-circular contoured rear end 
19, is rotationally coupled to the drive rod element 2 at a recess 20 that 
has a corresponding non-circular cross-section and an enlarged coupling 
segment 21 that is larger in diameter than the recess 20. 
In operation, in the "locked condition after key withdrawal" as depicted in 
FIG. 1, the steering shaft lock bolt member that typically is displaceable 
along its length transversely to the lock drive element 2, assumes a 
locked position in order to prevent rotation of the motor vehicle steering 
shaft. The ignition starter switch 4 in this condition cuts off current to 
the power consuming means of the vehicle. The core 14 of the lock cylinder 
3 and the drive rod element 2 are in the first, or outer, axial position 
whereat the coupling segment 21 of drive rod element 2 axially rests 
against the end of the cylinder housing 13 of the lock cylinder 3. 
When the key 18 is inserted into the core 14 of the lock cylinder 3 and 
rotated, the barrel core 14 and the drive rod element 3 are first axially 
driven against the force of the helical compression spring 10 seated on 
the shaft 8 and then rotated 180.degree. , whereupon the cam 7 of the 
drive rod element 2 will move the steering shaft locking member, which is 
spring biased normally towards the locked position, against its spring 
force into an unlocked position, whereby the motor vehicle steering shaft 
is now rotatable. At a point not later than when the unlocked condition is 
reached, a spring-loaded securing element (not shown) of the steering 
shaft locking member will snap over a safety projection 22 of the drive 
rod element 2, the projection 22 being located adjacent the cam 7 of the 
drive rod element 2 and having a circular contour. There then results the 
"drive" condition of the steering column lock as shown in FIG. 3 at which 
the ignition starter switch 4 has been rotated into the position to close 
the ignition circuit. 
Rotation of the key 18, the barrel core 14 and the drive rod element 2 back 
into the initial position leads to the "locked condition before key 
withdrawal", whereat the steering column lock components are positioned as 
shown in FIG. 4 and the cam 7 of the drive rod element 2 has released the 
steering shaft locking member which, however, remains held in the unlocked 
position due to the securing element of the steering shaft locking member 
resting on the safety projection 22 of the drive rod element 2. Only after 
the key 18 has been withdrawn from the cylinder core 14 of the lock barrel 
3 will the helical compression spring 10 drive both the drive rod element 
2 and the barrel core 14 out of the inner or second axial position as 
shown in FIG. 4 and into the outer or first axial position as shown in 
FIG. 1, whereby the safety projection 22 of the drive rod element 2 is 
moved away from beneath the securing element of the steering shaft locking 
member and this locking member, yielding to its spring-loading, moves into 
the locked position. 
To enable storing and shipping of the steering column lock without the lock 
cylinder 3 and the ignition starter switch 4 assembled thereto, the drive 
rod element 2 is retained securely in the housing, of the steering column 
lock in the manner shown in FIGS. 5 through 7. The drive rod element 2 is 
fitted with a radial projection 23 and the steering column lock housing is 
fitted with an inner enlarged annular recess 24 located between the 
ignition switch receiving end and the lock cylinder receiving end of the 
housing, and into which the projection 23 extends. A radial side wall 25 
of the recess 24 facing away from the helical compression spring 10 (and 
away from the ignition switch receiving end of the housing 1) includes a 
locking projection receiving recess 26 intersecting the side wall 25 
adjacent the bore hole 6 of the housing 1 that receives the lock cylinder 
3 as provided. The recess 26 receives an axially extending locking 
projection 28 that axially projects from the radial projection 23 when the 
drive rod element 2 is rotated so that the axially extending locking 
projection 28 is in alignment with the recess 26, which also extends 
axially. Preferably, the recess 26 is formed by the mouth of an inner 
longitudinal channel 27 in the steering column lock housing 1 extending 
axially along the bore of the housing to the side wall 25 of the enlarged 
annular recess 24. 
The locking projection 28 on the radial projection 23 of the drive rod 
element 2 is facing on the side of the projection 23 located away from the 
helical compression spring 10 and away from the ignition switch receiving 
end of the housing. The locking projection 28 is narrower than the radial 
projection 23 as shown in FIGS. 2, 6 and 7. As shown particularly in FIG. 
7, the width "a" of the inner longitudinal channel 27 of the housing 1 is 
only slightly larger than that width "b" of the locking projection 28 of 
the radial projection 23 of the drive rod element 2, and the width "c" of 
the projection 23 is substantially larger than the width "a" of the inner 
longitudinal channel 27 of the steering column lock housing 1. 
The projection 23 of the drive rod element 2 radially projects from a 
discoidal drive rod element segment 29 which projects radially from the 
drive rod element 2 and is mounted between the coupling segment 21 and 
that portion of the drive rod element that cooperates with the steering 
shaft locking member, in this case cam 7 and the safety projection 22. The 
locking projection 28 thus extends as a radial strip from the outer edge 
30 of the projection 23 and radially along the segment 29. Rod portion 31 
of drive rod element 2 connects the segment 21 to segment 29. 
When the drive rod element 2 is assembled into the bore 6 of the steering 
column lock housing 1, the radial projection 23 of the drive rod element 2 
moves along an inner axially extending longitudinal channel 32 in the bore 
of the housing that extends from generally the lock cylinder end of the 
housing to the enlarged annular recess 24 of the housing. The channel 32 
is slightly wider than the radial projection 23, as shown in FIG. 2, and 
is preferably offset by 180.degree. relative to the recess 26 in the bore 
of the housing. 
When it is desired to ship or store the steering column lock mechanism 
without the lock key cylinder 3, and perhaps without the ignition switch 
4, the drive rod element 2 is inserted into the bore 6 of the housing 1 
with the radial projection 23 aligned with the longitudinal channel 32 to 
enable axial movement of the drive rod element 2 into position within the 
bore such that the radial projection 23 extends into the enlarged annular 
recess 24 of the bore. Thereafter, the projection 23 and the locking 
projection 28 are rotated 180.degree. such that the locking projection is 
aligned with the locking projection receiving recess 26 in the bore of the 
housing. The spring 10, which is already assembled on the shaft 8, is then 
permitted to bias the drive rod element 2 axially towards the lock 
cylinder receiving end of the housing such that the locking projection 28 
extends into recess 26 to lock the drive rod element 2 against relative 
rotation in the housing 1. In this condition, the drive rod element 2 is 
safely secured in the bore of the housing against rotational and 
consequent axial displacement relative to the housing. 
To restore operability of the drive rod element 2, the lock cylinder 3 (and 
the ignition switch 4, if it has not already been installed) are installed 
in the housing 1 and the key 18 is inserted to cause axial and rotational 
displacement of the lock drive element 2 into the various conditions 
described previously. 
It will be noted from the drawings that the locking projection 28 does not 
engage the recess 26 until the lock cylinder 3 is removed from the 
housing. 
The axial motion of the drive rod element 2 out of the enlarged annular 
recess 24 is normally prevented by interference between the radial 
projection 23 and the radial wall 25 of the recess 24, except when the 
projection 23 is aligned with the recess 32 (see, for example, FIGS. 1 and 
2). 
It will be understood that the exemplary embodiment described is 
illustrative only and it will be understood that those skilled in the art 
could vary the details of the examples given without departing from the 
scope of the invention as defined in the appended claims.