Universal joint lock

A member formed of saw and bolt cutter resistant, hardened steel which is insertable between the arms of the U-joint of a truck steering system and locked in place by one or more padlocks. So installed, the member prevents steering of the truck, thereby preventing theft of the truck.

Theft of vehichles of all kinds has always been a problem, and the 
frequency thereof has markedly increased as the economic situation 
worsens. 
This is particularly true with respect to trucks, and the solution of the 
problem has heretofor been virtually unsolvable, except for the usual 
procedures of locking the doors and windows of the cab. However, these 
conventional procedures are ineffective against the serious thief who can 
easily pick a lock or break a window. 
Therefore, the primary objective of this invention is to provide means for 
inhibiting movement of the steering mechanism of an automotive vehicle, 
especially trucks, to discourage and prevent the theft thereof. 
Another object is to provide means for inhibiting the steering movement of 
an automotive vehicle which incorporates a universal joint as a part of 
its steering mechanism. 
Still another object is to provide means for locking against movement the 
steering mechanism of a truck which has a universal joint incorporated 
therein by inhibiting movement between the cooperating yokes of the 
universal joint. 
Another object is to inhibit steering movement of an automotive steering 
mechanism having a universal joint forming an integral part thereof by 
relatively inexpensive, easy to operate means comprising a member 
removeably insertable between the opposing yokes of the universal joint to 
inhibit movement therebetween, and means for locking said member in place 
so that it cannot be removed by anyone other than the owner or user, such 
as vandals, thieves or mischievious children.

Referring to the drawings, and initially to FIG. 1, said Figure shows a 
typical Cab-Over-Engine truck tractor T having an operation cab which 
includes a seat S and a steering wheel W. The steering wheel operates a 
steering mechanism which includes an upper shaft 10 rotatably driven by 
the steering wheel W and a lower shaft 11 which are connected to each 
other for relative movement therebetween by a universal joint indicated in 
its entirety by J which includes an upper yoke unit 13 connected to and 
operated and driven by upper shaft 10 and a lower yoke unit 14 connected 
to lower shaft 11 for driving or turning same, the lower shaft 11 through 
its normal turning movement causing the steering movement of the vehicles 
ground engaging wheels. 
Prior to this invention, this type of vehicle has been extremely vulnerable 
to theft, and the steering lock mechanisms conventionally installed in 
modern day passenger cars are not readily adaptable to this type of truck 
steering mechanism, and no locking mechanism for the steering mechanism is 
provided by the truck or tractor manufacturer as standard equipment. 
The invention involves the use of movement inhibiting means such as the 
locking bar 15 which is a rigid elongate member formed of saw-resistant 
hardened steel which is adapted to be inserted between the two yoke units 
13 and 14 and then locked in place by means of locking means such as a 
single padlock 16, or with the aid of a second or extra padlock 17. Where 
so installed, the locking bar 15 inhibits or totally prevents relative 
movement between the two yoke units 13 and 14, thereby preventing any 
significant or useful steering of the vehicle by manipulation of the 
steering wheel W. 
The locking bar 15 may be formed in any convenient manner, but in one 
preferred form it is the result of a stamping operation. 
The locking bar has a main elongate body portion 18 which having straight 
parallel opposing sides 19 and 20, the distance between 19 and 20 
representing the main width of the locking bar which is installed between 
the opposing upstanding yoke arms 14a and 14b of the lower yoke unit. Said 
width of the bar may vary according to the types of universal joints in 
which it is to be installed, but in a typical preferred embodiment the 
preferred embodiment is 11/4 inches. In any event, the width is such as to 
fit between the yoke arms 14a and 14b, and preferably fairly snugly to 
minimize the amount of play the locking bar might be subjected to, and yet 
narrow enough to permit easy insertion of the locking bar, it being 
understood that the locking bar is inserted while the yoke units 13 and 14 
jointed together. 
Side 20 of the bar has a concave slot 21 formed therein for receiving the 
shackle 17a of another locking means such as padlock 17. The slot 21 is of 
such depth that the distance d1 between its deepest part and side 19 
approximates the distance between the outermost part of the shackle 17a 
and the main body or box 17b of the padlock 17 when it is locked in place, 
so that padlock 17 cannot be slid off or otherwise removed from the 
locking bar. 
The bar 15 has a circular leading end or head 22 which is also capable of 
passing between the yoke arms 14a and 14b, and which in one preferred 
embodiment has a widthwise diameter slightly larger than the main width 
between sides 19 and 20. 
The four edges or corners 23 of head 22 are cut off at a slant or chamfered 
or beveled to facilitate insertion and removal, with the chamfering 
extending logitudinally with respect to the locking bar. The chamfered 
corners are best seen in FIG. 6. 
The head 22 has a circular opening 24 formed therein for receiving the 
shackle 16a of padlock 16 to lock the locking bar in place. 
At the other end of the locking bar a generally ovate locking or movement 
limiting head 25 is provided, which is substantially larger than the main 
width of the locking bar 15, and larger than the distance between the yoke 
arms 14a and 14b, so that it cannot pass therebetween. In a typical 
preferred embodiment that maximum width d2 of head 25 represented by its 
outer ends 25a and 25b, is about 21/2 inches, this enlarged head giving 
the locking bar a generally "T" shaped appearance when seen from above, as 
in FIG. 4, and also gives it an appearance somewhat similar to a key. 
Thus, the main shaft 18 is smaller in width than both heads 22 and 25. 
The head 25 is provided with a circular opening 26 for receiving a chain 
(not shown) or some other flexible element to enable the bar to be chained 
or tethered to the doghouse or some other part of the tractor to prevent 
its being lost and to keep it conveniently available for use at all times. 
Head 25 limits the longitudinal movement of bar 15 in a direction in which 
head 25 trails and head 22 leads. 
The locking bar 15 has a substantially flat top surface 27 and a 
substantially flat bottom surface 28 which are substantially parallel 
opposed surfaces, with the distance d3 therebetween representing the 
thickness of the locking bar, which thickness in a typical preferred 
embodiment being on the order of 7/16 inches. In some embodiments, the top 
surface 17 may be very slightly convexly curved as seen in cross-section, 
and the bottom surface 28 may be very slightly concavely curved, when 
viewed in cross-section. 
This thickness d3 must be such that when installed and in place it prevents 
any significant relative movement between the yoke sections 13 and 14, and 
more specifically the movement of the upper yoke 13 relative to the lower 
yoke 14. 
In operation, the operator of the vehicle, in order to prevent theft 
thereof, simply inserts the head 22 of the bar between the yoke arms 14a 
and 14b of the lower yoke section 14, and under the yoke arms 13b of the 
upper yoke unit 13 and slides it longitudinally until the opening 24 
extends sufficiently far out on the side opposite head 25 so that padlock 
16 can be installed in opening 24 if only a single padlock is used. If two 
padlocks are to be used, or if only one padlock such as 17 is to be used 
in conjunction with slot 21, then the locking bar 15 must be pushed far 
enough through to enable the shackle 17a of padlock 17 to be installed 
around the width of the bar in the slot 21. 
Thus, it is self-evident that the locking bar 15 must be long enough for 
the slot 21 to clear the yoke arm 13b of the upper yoke section to permit 
lateral installation of a padlock in slot 21. 
Once locked, the padlocks stay that way until opened by a suitable key K. 
There may be a single key usable in both padlocks, or they may each have 
their own key. 
When the locking bar is installed, the inner edges of the head 25 may or 
may not abut with the yoke arms 14a and 14b, but the head will not pass 
between yoke arms 14a and 14b, and therefore the locking bar is prevented 
from being pulled longitudinally through the universal joint by head 25. 
The padlocks prevent the locking bar from being pushed or longitudinally 
with the head 25 leading and head 22 following, because of the padlocks 
engagement with either or both of the yoke sections. 
Padlocks such as those sold under the tradename Abloy are preferred, since 
both sides of thin shackles must be cut before they can be removed from 
the locking bar. Thus, the potential thief must cut each shackle twice in 
order to remove the locking bar and free the universal joint and the 
steering mechanism. 
It is to be understood that a single padlock installed either vertically in 
the locking bar in opening 24 or horizontally in slot 21 will successfully 
lock the bar 15 in place. Two padlocks are used simply to double the 
difficulty of releasing the locking bar 15. 
Thus, the illustrated and described locking mechanism of this invention 
provides protection from theft when the truck is idled for extended 
periods during cold weather, when in truck stop line-ups, when parked in 
motel parking lots, when parked for food and fuel stops, and when parked 
in dealer and fleet parking lots. 
Since the invention prevents stealing of the tractor, it also protects the 
trailer attached to the tractor and any cargo carried therein. 
Although the invention has been illustrated as used with a truck tractor, 
it has broader applicability, being usable also with farm and construction 
equipment which uses a universal joint between the steering wheel and the 
steering unit, either power or mechanical for the vehicle or equipment 
directional means such as wheels. 
In a broader context, the invention is applicable to any system involving a 
universal joint where it is desirable to prevent relative movement between 
the yoke section of said joint for whatever reason. 
To give some idea of the importance of this invention, the FBI reports that 
approximately 19,000 tractors and 20,000 trailers are stolen each year, 
and this reflects only vehicles engaged in inter-state commerce, and does 
not reflect the number stolen in intra-state traffic. 
Thus, by simply installing the locking bar 15 between the yoke sections of 
a universal joint and locking it in place, relative movement between the 
yoke sections is prevented, the universal joint ceases to function, and if 
it is part of a vehicle steering mechanism, it prevents steering of the 
vehicle, and thereby prevents stealing thereof. 
To function properly, the ends of the upper yoke arms 13b must be 
substanitially parallel with each other and substantially equidistant from 
the curved bight portion of the lower yoke section, when the locking bar 
is installed. When so positioned, the wheels of the tractor are 
substantially straight, so that the vehicle is restricted to forward and 
reverse operation only when the locking bar is in place. 
It will also be noted that it is desirable to use padlocks which are highly 
resistant to cutting with bolt cutters or saws, so that it is hard to cut 
both the padlocks and the locking bar. 
It will also be noted that the head 25 is wider than the distance between 
the yoke arms 14a and 14b and is adapted to engage said yoke arms, and 
when so engaged limits and prevents further movement of the lock bar 15 in 
one direction, namely the installational direction in which the head 22 
leads and head 25 follows. 
It will, of course, be understood that various changes may be made in the 
various parts and dimensions referred to and illustrated herein, without 
departing from the scope of this invention.