Steering lock

A steering lock, which includes a casing for mounting on an inner periphery of a steering wheel, having a front track and a rear track separated by an arched mounting hole, a lock cylinder at the front, and a steel ball supported on a spring in a hole within the rear truck. A constraint bar is fixed to the casing for abutting the instrument panel of an automobile. A slide block is adapted to slide between the front and rear tracks and guided by a guide screw on the casing. The slide block has a recessed hole which receives the latch bolt of the lock cylinder when the steering lock is locked or the steel ball when the steering lock is unlocked.

BACKGROUND OF THE INVENTION 
The present invention relates to a steering lock for locking the steering 
wheel of a motor vehicle. 
Various automobile locking devices are known and intensively used for 
locking the steering wheel or gear shift lever. FIG. 1 shows a steering 
lock according to the prior art, which comprises a substantially T-shaped 
mounting frame fastened to the periphery of the steering wheel by the 
shackle of a lock body, and a constraint bar having one end connected to 
the lock body and an opposite end stopped at the instrument panel of the 
automobile. This structure of steering lock is not satisfactory in 
function because it cannot protect against the use of a hammer and bar and 
can be easily destroyed by burglars. 
SUMMARY OF THE INVENTION 
The present invention provides a steering lock which eliminates the 
aforesaid problem. It is one object of the present invention to provide a 
steering lock which protects against the use of a hammer and bar. It is 
another object of the present invention to provide a steering lock which 
can be automatically retained at the unlocked position for the next 
locking operation when it is unlocked. It is still another object of the 
present invention to provide a steering lock which is easy to operate. It 
is still another object of the present invention to provide a steering 
lock which is durable in use. 
To achieve the aforesaid objects, there is provided a steering lock 
comprised of a casing, a slide block fastened to the casing and locked in 
the locking position permitting the casing to be firmly retained to the 
steering wheel to be locked, and a constraint bar extended from the casing 
for abutting the instrument board panel of the motor vehicle. The casing 
has a front track and a rear track separated by an arched mounting hole, a 
lock cylinder at the front controlled to lock the slide block in the 
locking position, and a steel ball supported on a spring in a hole within 
the rear track to hold the slide block in the rear track when the steering 
lock is unlocked. The slide block is guided by a guide screw and moved 
between the front and rear tracks, having a recessed hole which receives 
the latch bolt of the lock cylinder when the steering lock is locked or 
the steel ball when the steering lock is unlocked. The slide block further 
comprises a rear bumper transversely disposed at the back thereof to 
protect against insertion of a bar into the rear track when removing the 
slide block from the casing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 2 and 3, a steering lock in accordance with the present 
invention is generally comprised of a casing 1, a slide block 2, and a 
constraint bar 3. 
The casing 1 comprising an arched mounting hole 10 transversely disposed at 
the top in the middle for receiving the periphery of the steering wheel 5 
to be locked (see FIG. 8). The periphery of the arched mounting hole 10 is 
covered with a cushion 100. The cushion 100 can be compressed when the 
casing 1 is fastened to the periphery of the steering wheel 5 and locked. 
Therefore, the arched mounting hole 10 can fit a variety of steering 
wheels. The casing 1 is divided by the arched mounting hole 10 into two 
opposite parts, namely, the front part and the rear part. A lock cylinder 
11 is fastened to the front end of the front part of the casing 1 in the 
center. A rectangular hole 12 is made on the rear end of the rear part of 
the casing 1 in the center to hold one end of the constraint bar 3. The 
casing 1 further comprises a front track 13 and a rear track 13' 
respectively disposed on the front and rear parts thereof at the top and 
longitudinally aligned for the sliding of the slide block 2 (see FIGS. 4 
and 5). A transverse groove 130 is made on the front part of the casing 1 
at the top and disposed within the front track 13 for mounting a locating 
block 14. The locating block 14 has a bottom rib 141 fitted into the 
transverse groove 130, and two springs 140 bilaterally disposed in the 
front track 13. The rear part of the casing 1 comprises a plurality of 
screw holes 130' at the top within the rear track 13'. A steel ball 131' 
is supported on a spring 132' in a hole (not shown) on the top of the rear 
part of the casing 1 within the rear track 13'. 
The slide block 2 comprises a flat bottom rail 20 made to slide in and out 
of the front and rear tracks 13 and 13', and a rear bumper 23 transversely 
disposed at the back. The bottom rail 20 of the slide block 2 has a 
longitudinal bottom groove 21 and a recessed hole 22 in the front of the 
longitudinal bottom groove 21. 
The constraint bar 3 is a narrow flat bar, having a front end received in 
the rectangular hole 12 on the rear part of the casing 1 and then fixed in 
place by threading screws 4 into the screw holes 130' on the rear part of 
the casing 1 and respective screw holes 30 on the front end of the 
constraint bar 3. When the bottom rail 20 of the slide block 2 is inserted 
into the rear track 13', a guide screw 40 is threaded into a bottom screw 
hole (not shown) on the casing 1 with the end projecting into the 
longitudinal groove 21 to guide the movement of the slide block 2 in the 
tracks 13 and 13'. When the slide block 2 is disposed in the rear track 
13', the steel ball 131' engages the recessed hole 22 on the bottom rail 
20 to retain the slide block 2 in the unlocked position (see FIG. 6). 
Referring to FIG. 7, when the slide block 2 is moved into the front track 
13 to compress the springs 140 of the locating block 14, the latch bolt 
110 of the lock cylinder 11 is driven out of a hole (not shown) on the top 
of the front part of the casing 1 and inserted into the longitudinal 
groove 21 on the bottom rail 20 of the slide block 2, and therefore the 
slide block 2 is locked in the locking position. Because the guide screw 
40 is perpendicularly inserted into the longitudinal groove 21 on the 
bottom rail 20 of the slide block 2, the movement of the slide block 2 in 
the tracks 13 and 13' is limited within a fixed range, and therefore the 
locating block 14 will not be damaged when the slide block 2 is pushed 
into the locking position. When locked, the rear bumper 23 of the slide 
block 2 and protects blocks up the gap between the casing 1 and the slide 
block 2 against the insertion of a bar. When the latch bolt 110 is 
released from the bottom rail 20 of the slide block 2, the springs 140 
automatically push the slide block 2 away from the front track 13. When 
the slide block 2is moved back to the rear track 13' by the springs 140, 
the guide screw 40 abuts the front end of the longitudinal groove 21, 
causing the steel ball 131' to engage the recessed hole 22 again, and 
therefore the slide block 2 is retained in the unlocked position. 
Furthermore, the front track 13 defines two cylindrical receiving spaces at 
two opposite sides in the longitudinal direction respectively fitting the 
outer diameter of the springs 140. Therefore, the spring 140 can be 
compressed in the longitudinal direction and will not be tilted when 
compressed (see also FIG. 5).