Wheel lift towing assembly

A wheel lift tow assembly 28 is mounted to the frame at the rear of a tow truck 20 and is movable vertically by a power cylinder 60 connected between the frame of the tow truck and the tow assembly. The tow assembly includes a telescopic tow bar 35 that is distended and retracted by a power cylinder 65, and a cross arm 36 which is pivotably mounted intermediate its ends about an upwardly extending axis 89 to the rear portion of the telescopic tow bar. Sleeve members 92, 93 are slidably mounted about the opposite ends of the cross arm, and L-shaped wheel cradles 37, 38 are releasably connected to the sleeve members.

BACKGROUND OF THE INVENTION 
The invention disclosed herein relates to attachments for tow trucks which 
lift and tow automobiles and other wheeled vehicles behind the tow truck. 
More particularly, the invention relates to a tow assembly that includes 
wheel cradles that receive the front or rear wheels of an automobile and 
lift the wheels and therefore one end of the automobile from the ground 
surface without engaging other parts of the automobile. 
When an automobile is to be towed, the operator of the tow truck must be 
very careful that a firm connection is made between the tow truck and the 
automobile, and also to assure that the automobile will not be damaged as 
it is lifted and towed. For example, the front and rear ends of 
automobiles typically include bumpers, lights and other decorative objects 
that are easily scratched, broken or otherwise damaged. Recently, 
automobiles have been manufactured with wind deflectors or "spoilers" that 
protrude downwardly from the front portion of the vehicle, and it is 
difficult to connect the typical towing device to the automobile without 
damaging one or more of these objects. 
In the past, one of the more popular tow attachments for two trucks has 
been a flexible sling attached to a tow bar which extends beneath the 
automobile that is to be towed and extends around the bumper and is lifted 
with the typical boom and cable of the tow truck. While the flexible sling 
tends to protect the bumper and other objects from abrasion, etc., a force 
is applied by the sling to the front spoiler, the bumper, and other 
objects that it contacts, such that there is a significant hazard of 
damaging the automobile. 
Other type tow assemblies for connection to tow trucks are available which 
do not require the conventional sling assembly but include wheel engaging 
structures or "wheel cradles" which engage the front or rear wheels of an 
automobile to lift the wheels and therefore one end of the vehicle, 
substantially without engaging any other portion of the vehicle. 
Typically, these devices include a tow bar connected to the rear of the 
tow truck, wheel cradles connected to the tow bar, and a boom and winch 
assembly that has a cable that extends over the rear of the tow truck and 
is connected to the tow bar to lift and support the tow bar. Examples of 
these devices are generally disclosed in U.S. Pat. Nos. 3,434,607, 
3,690,482, 3,924,763, and 3,897,879. 
Some of the problems present in the prior art wheel lift tow assemblies are 
that the wheel cradles are difficult to mount to the wheels of the 
automobile that is to be towed, the tow assembly supports the raised 
wheels of the automobile at a distance so far from the rear of the tow 
truck that the weight of the vehicle lifted by the tow truck tends to 
counterbalance the front of the tow truck such that the steerable wheels 
of the tow truck do not have enough weight applied to them for safe 
handling. Other problems include retraction and storage of the tow 
assembly with respect to the tow truck when the tow assembly is not to be 
used, and the large size and weight of the wheel cradles and their 
associated elements which makes the wheel cradles difficult to handle by 
the truck operator. 
SUMMARY OF THE INVENTION 
Briefly described, the present invention comprises a wheel lift tow 
assembly for mounting to a tow truck which includes a tow bar having 
telescopic sections that distend and retract, a cross arm pivotably 
mounted intermediate its ends about an upwardly-extending axis to the rear 
end portion of the tow bar, and wheel cradles positioned at opposite ends 
of the cross arm for engaging the wheels of a vehicle to be towed. In one 
embodiment a parallel linkage is connected to the tow bar, and the 
parallel linkage is to be connected to the frame at the rear of a tow 
truck. This maintains the tow bar in a substantially horizontal attitude 
as it is being raised and lowered by a hydraulic cylinder or other power 
means connected between the frame and the parallel linkage. 
In another embodiment of the invention sleeve members are movably mounted 
to the opposite end portions of the cross arm and the wheel cradles are 
releasably connectable to the sleeve members. This permits the wheel 
cradles to be moved closer together or further apart to accommodate 
vehicles having wheels spaced apart at different distances. A sling 
attachment is provided which includes sling support bars mountable to 
opposite end portions of the cross arm, and flexible sling straps are 
attached at one of their ends to the sling support bars. This enables the 
tow assembly to be used in a configuration similar to the conventional 
sling lift arrangement. Also, a ball hitch attachment is provided which is 
connectable to the cross arm for towing trailers. 
The invention is self contained and does not have to rely upon any other 
devices such as a boom and cable of conventional recovery wrecker 
equipment. Rigid members support the towed vehicle so that no cables, 
straps or other flexible members are required which are more likely to 
break due to abrasion, rot or fatigue. 
Thus, it is an object of this invention to provide a wheel lift tow 
assembly for mounting to the rear portion of a tow truck and which can be 
lowered to the ground surface and distended rearwardly with respect to the 
tow truck so as to position a cross arm adjacent the wheels of a vehicle 
to be towed. Wheel cradles then can be mounted about the wheels of the 
vehicle and attached to the cross arm, and the cross arm can be raised to 
lift the adjacent end of the vehicle and then retracted back toward the 
rear end of the tow truck so as to bring the vehicle to a position closely 
adjacent the rear of the tow truck. 
Preferably, the rear end portion of the tow truck will have a low profile 
so that when the wheel lift tow assembly lifts the wheels of an 
automobile, the tow assembly can be retracted so as to bring the bumper 
and other parts of the automobile that extend in front of the wheels over 
the rear portion of the tow truck, thereby placing the weight of the load 
carried by the tow assembly as close as possible to the rear wheels of the 
tow truck. 
Thus, it is another object of this invention to provide a wheel lift tow 
assembly for mounting to tow trucks which engages and raises the wheels of 
a vehicle and brings the vehicle in overlying relationship with respect to 
the rear portion of the tow truck, so as to place the load of the towed 
vehicle closely adjacent the rear wheels of the tow truck. 
Another object of this invention is to provide a wheel lift tow assembly 
for tow trucks which is inexpensive to construct and to maintain, which 
engages only the wheels of a vehicle to be towed during the lifting and 
towing functions, and which can be safely and expediently operated to tow 
vehicles. 
Another object of this invention is to provide a wheel lift tow assembly 
which is versatile in operation and which can be converted to a sling lift 
and tow configuration and to a ball hitch tow configuration. 
Other objects, features and advantages of the present invention will become 
apparent upon reading the following specification, when taken in 
conjunction with the accompanying drawings.

DETAILED DESCRIPTION 
Referring now in more detail to the drawings, wherein like numerals 
indicate like parts throughout the several views, FIG. 1 illustrates a tow 
truck 20 of conventional construction which includes a chassis 21 with a 
frame, and rear driving wheels 22. The tow truck optionally includes a 
boom 24 with a cable 25 extending over the upper end of the boom, and a 
winch (not shown) is enclosed in housing 26 for paying out and reeling in 
the cable 25. Wheel lift tow assembly 28 is mounted to the rear frame of 
the tow truck 20 and extends rearwardly thereof behind the rear driving 
wheels 22. As illustrated in FIG. 1, the wheel lift tow assembly 28 is 
capable of lifting a towed vehicle, such as automobile 29, by engaging and 
lifting the wheels 30 of the automobile. After the automobile has been 
lifted, the wheel lift tow assembly can be retracted so as to bring the 
bumper 31 and other portions of the vehicle which extend in front of the 
wheels 30 to a position above the low profile rear end portion 32 of the 
tow truck 20. This places the load as transmitted through the wheels 30 of 
the automobile 29 closely adjacent the rear driving wheels 22 of the tow 
truck 20. 
As illustrated in FIGS. 2 and 3, the wheel lift tow assembly 28 comprises a 
tow bar 35, cross arm 36 and wheel cradles 37 and 38. Tow bar 35 is 
supported by a parallel linkage 39 which is to mounted beneath the rear 
portion of the tow truck, to the frame elements 40 and 41 of the tow 
truck. 
Parallel linkage 39 comprises rigid support bracket 42 which is to be 
mounted to and suspended from the frame elements 40 and 41 of the tow 
truck. Support bracket 42 includes a first pair of parallel support plates 
44 and 45, each having one end portion thereof rigidly attached to frame 
element 40, and a second pair of parallel support plates 46 and 47 each 
having one end thereof attached to frame element 41. The lower, 
rearwardly-projecting end portions of the first pair of parallel support 
plates 44 and 45 are each rigidly connected to the lower, 
forwardly-extending portions of the second support plates 46 and 47, 
respectively. The joined lower portions of the parallel support plates 
44-47 form a pair of vertically-extending arms of the parallel linkage, 
and the axles 48 and 49 extend through and are positioned in vertically 
spaced relationship with respect to one another by the forward assembly. 
Lower and upper pairs of parallel linkage arms 50, 51 and 52, 53 are each 
pivotably mounted to the axles 48 and 49 and extend rearwardly from the 
axles. A pair of vertically-oriented parallel linkage arms 54 and 55 are 
each pivotably mounted to the rear end portions of the lower and upper 
pairs of parallel linkage arms 50-53 by axles 56 and 57. With this 
construction, the vertical parallel linkage arms 54 and 55 can move 
vertically and substantially maintain their vertical orientation. 
Hydraulic cylinder 60 is mounted generally between the pairs of parallel 
support plates 44-47 of support bracket 42, with the cylinder 60 being 
pivotably mounted to axle 61 mounted in bracket 42 and with its piston rod 
62 attached to the axle 57 at the upper ends of the vertical parallel 
linkage arms 54 and 55. When piston rod 62 is distended, the 
vertically-oriented parallel linkage arms 54 and 55 will be moved 
downwardly while maintaining their vertical orientation, whereas when 
piston rod 62 is retracted, the verticially-oriented parallel linkage arms 
54 and 55 will be raised while still maintaining their verticial 
orientation. 
Tow bar 35 comprises three telescoping tubes 61, 62 and 63. The tubes 61-63 
are rectangular in cross section, with tube 62 being smaller in cross 
section than tube 61, and with tube 63 being smaller in cross section than 
tube 62. Tube 61 is rigidly mounted to the vertically-oriented parallel 
linkage arms 54 and 55 of parallel linkage 39, with the tube 61 having its 
length oriented in a horizontal attitude. Since the parallel linkage arms 
54 and 55 are maintained in an upwardly-extending attitude, the base 
telescopic tube 61 will be maintained in its horizontal attitude as it is 
raised and lowered with the parallel linkage 39. Hydraulic cylinder 65 is 
positioned within the telescopic tow bar 35, with the cylinder being 
connected at its end portion to outer base telescopic tube 61 by 
connecting pin 66. The piston rod 68 of cylinder 65 is extendable beyond 
the rear end portion 69 of the telescopic tube 61, as indicated. 
The intermediate telescopic tube 62 defines aligned sides openings 70 (only 
one shown) in its sidewalls, and connector pin 71 is insertable through 
the aligned openings. Similarly, the sidewalls of inner telescopic tube 63 
define pairs of aligned openings 72 and 73 (only one of each shown). The 
distal end of piston rod 68 includes a boss 75, and the boss 75 includes 
an opening. The connector pin 71 is insertable through the aligned side 
openings 70 of the intermediate telescopic tube 62, through one of the 
pairs of aligned openings 72, 73, etc. of the inner telescopic tube, and 
through the opening 76 of the boss 75 of the piston rod 68. With this 
arrangement, when the piston rod 68 is moved with respect to its cylinder 
65, both the inner and intermediate telescopic tubes 63 and 62 will move 
in unison with piston rod 68. If it is desirable to have the inner 
telescopic tube 63 distended further from within intermediate telescopic 
tube 62, the connector pin 71 can be withdrawn from the aligned openings, 
the inner telescopic tube 63 manually distended from intermediate 
telescopic tube 62 until another one of the openings 72, 73, etc. of the 
inner telecopic tube 63 is aligned with the openings 70 and the opening 
through boss 75, whereupon the connector pin 71 is reinserted through the 
aligned openings. In order that the intermediate telescopic tube 62 can be 
fully retracted within the outer telescopic tube 61, the rear end portion 
69 of the outer telescopic tube 61 defines a slot 78 which receives 
connector pin 71. 
Cross arm 36 is pivotably mounted to tow bar 35 by means of clevis 80. 
Protrusion 81 extends from inner telescopic tube 63 rearwardly towards 
cross arm 36, and clevis 80 includes upper and lower leaves 82 and 83 that 
straddle protrusion 81, and clevis mounting plate 84 which is rigidly 
connected to upper and lower clevis leaves 82 and 83. Vertically aligned 
openings (FIG. 14) are formed in the upper and lower clevis leaves 82 and 
83 and through the protrusion 81, and axle assembly 85 extends through the 
aligned openings. Axle assembly 85 is oriented upwardly and includes a 
tube 86 extending through the aligned openings and an upper flange 87 that 
overlies upper clevis leaf 82. Tube 86 is internally threaded. With this 
arrangement, the axle assembly 85 supports cross arm 36 about 
upwardly-extending axis 89. 
It will be noted that the upper portion 90 of the rear end portion 69 of 
the outer telescopic tube 61 overhangs the lower portion 91. Also, the 
upper surface of flange 87 of axle assembly 85 is relatively thin so that 
it can be retracted within the inner and outer telescopic tubes 62 and 61. 
With this arrangement, when both the inner and intermediate telescopic 
tubes 63 and 62 are retracted within the outer telescopic tube 61, the 
overhanging end portion 90 of the outer telescopic tube 61 will receive 
the side edges of the upper leaf 82 of clevis 80. Should the cross arm 36 
be oriented at an angle other than a right angle with respect to the tow 
bar 35, the overhanging upper end portion 90 of the outer telescopic tube 
61 will engage the side edge of the upper clevis leaf and cause the clevis 
and the cross arm 36 to be pivoted back to a right angle position about 
axis 89. 
As illustrated in FIG. 3, cross arm 36 comprises a rectilinear bar 91 
mounted intermediate its ends to clevis 80. Sleeve members 92 and 93 are 
mounted about the end portions of the rectilinear bar 91. Each sleeve 
member comprises a rectangular tube 96 that snugly fits about the 
rectilinear bar 91, and a wheel support skid 97 which is mounted to one 
side of rectangular tube 96. Wheel skid 97 includes a wheel-engaging 
surface 98 connected at its upper edge portion to the rectangular tube 96, 
and a flange 99 that is turned inwardly toward the same surface of the 
rectangular tube 96, so that the wheel-engaging surface 98 is angled so as 
to engage the surface of a wheel 30 (FIG. 1) in flat abutment. A plurality 
of ribs 100 are formed on the wheel-engaging surface 98 so as to avoid 
inadvertent turning of a wheel in engagement with the wheel-engaging 
surface 98. 
Mounted to the outer ends of each sleeve member 92 and 93 is a rectangular 
socket 103, and protector plates 104 are mounted in a vertical plane to 
the outer surfaces of the sockets 103. The rectangular socket opening 105 
of each socket 103 extends horizontally and is arranged to receive a wheel 
cradle 37 or 38. 
As illustrated in FIG. 4, each sleeve member 92 and 93 includes a friction 
plate 108 internally thereof, and externally-threaded screw 109 extends 
through internally-threaded boss 110 into abutment with the friction 
plate. When screw 109 is rotated so that it projects further through boss 
110 into the sleeve member 92 or 93, its friction plate 108 is forced 
against the rectilinear bar 91 of cross arm arm 36, thereby fastening the 
sleeve member to the rectilinear bar. On the other hand, when screw 109 is 
rotated in the opposite direction so as to be withdrawn from sleeve member 
92 or 93, its friction plate 108 will no longer be forced against the 
rectilinear bar 91, and the sleeve member 92 or 93 can then be moved along 
the length of its end portion of the rectilinear bar. 
As illustrated in FIG. 3, wheel cradles 37 and 38 are mirror images of each 
other, and each includes the sleeve member 92 or 93, and an L-shaped wheel 
support bracket 112 comprising a connector arm 113 and a wheel support arm 
114 oriented at right angles with respect to each other. The connector arm 
113 is rectangular in cross section and is sized to be snugly received 
through rectangular socket opening 105 of a sleeve member 92 or 93. A 
plurality of openings 116 are formed at spaced intervals along the length 
through connector arm 113. As illustrated in FIG. 4, a lock pin 118 is 
movably mounted to each sleeve member 92 and 93, with the lock pin 
extending through boss 119, and spring-urged toward the rectangular socket 
opening 105. Lever 120 is attached to lock pin 118 at a right angle to 
facilitate withdrawing lock pin 118 from its boss 119. A coil compression 
spring (not shown) is located within boss 119 and urges lock pin 118 
toward the end of its sleeve member 92 or 93. With this arrangement, when 
the connector arm 113 of the L-shaped wheel support bracket 112 is 
inserted through a rectangular socket opening 105 of a sleeve member 92 or 
93, the pin 118 can be withdrawn against the bias of its spring until the 
connector arm is properly located within the socket 113, and then the 
lever 120 released so that the spring will urge lock pin 118 toward 
engagement with the connector arm 113, and if one of the openings 116 of 
the connector arm 113 is aligned with the pin 118, the pin will be 
received in the opening and will lock the connector arm in place within 
the socket 103. 
As illustrated in FIGS. 1 and 3, tie-down straps 121 are mounted to the 
connector arm 113 of each L-shaped wheel support bracket 112. A ratchet 
122 is arranged to reel out and reel in the tie-down strap. The tie-down 
straps are made in the form of a loop with a metal ring 124 sewn in the 
end portion of the tie-down strap and surrounding the intermediate portion 
of the tie-down strap. With this arrangement, the loop of the tie-down 
strap is enlarged and fitted over the upper portion of the wheel 30 (FIG. 
1) of the automobile, and the tie-down strap is then tightened by 
manipulation of the ratchet 122. 
With this arrangement, the cross arm 36 of the wheel lift tow assembly can 
be lowered to ground level and positioned in front of the wheel 30 of the 
vehicle to be towed, and the L-shaped wheel support brackets 112 fitted 
about the wheels, with the connector arm 113 positioned beside and outside 
of a wheel and the wheel support arm 114 positioned behind the wheel, with 
the connector arm 113 aligned with the rectangular socket opening 105 of a 
sleeve member 92 or 93, and then the L-shaped wheel support bracket is 
moved forwardly so that its connector arm 113 is received in and 
telescopically moves through the rectangular socket opening 105 until the 
wheel support arm 114 engages the rear curved surface of the wheel 30. As 
the connector arm 113 is moved through the socket 103, the lock pin 118 is 
withdrawn from the socket 103. When the connector arm 113 has been moved 
as far as possible through the socket 103, the operator releases the lock 
pin 118, so that the lock pin is thrust by its spring through one of the 
openings 116 of the connector arm. This causes the wheel support arm 114 
of the L-shaped wheel support bracket to be maintained at a fixed distance 
from its sleeve member 92 or 93 and the rectilinear bar 91, so that the 
L-shaped support bar 112 and its sleeve member 92 or 93 function as a 
wheel cradle, to cradle and support the wheel, to cause the wheel to be in 
engagement with the wheel support arm 114 and with the wheel skid 97 of 
the sleeve element. 
After the wheel cradle has been formed about a wheel 30 and after the 
wheels of the automobile has been lifted from the ground by the assembly, 
tie-down straps 121 are looped over the upper portion of the wheels 30 
(FIG. 1), and the ratchets 122 are tightened to shorten the lengths of the 
straps and to hold the wheels 30 in their cradles. 
As illustrated in FIGS. 6, 7, 8 and 9, a trailer hitch 126 is provided for 
connection to cross arm 36. Trailer hitch 126 includes channel bracket 128 
that fits about the rear, upper and lower surfaces of the rectilinear bar 
91 of cross arm 36, and connector strap 129 which is rigidly mounted to 
the upper surface of channel bracket 128. An opening 130 is formed in 
channel bracket 128 to fit about the external part of spring ball assembly 
131 that protrudes from the cross arm 36. Counter-bored opening 132 is 
formed through the forward portion of connector strap 129, and screw 134 
is insertable through the opening 132 into the internally-threaded opening 
of tube 86 of axle assembly 85. This rigidly connects trailer hitch 126 to 
cross arm 36. The connector strap 129 projects rearwardly of the channel 
bracket 128, and a conventional ball trailer hitch element 136 is mounted 
thereon. 
As illustrated in FIGS. 7 and 8, the trailer hitch 126 is movable with 
cross arm 36 about the upwardly-extending axis 89, so that the ball hitch 
is movable laterally with respect to tow bar 35. This enables the operator 
of the tow truck 20 to back the tow truck toward a trailer, and if the 
ball hitch 136 is slightly misaligned with respect to the hitch of the 
trailer, the ball hitch 136 can be moved laterally by rotating cross arm 
36. On the other hand, when both the inner and intermediate telescopic 
tubes 62 and 63 are retracted as indicated in FIG. 9, the outer, upper end 
portion 90 of the outer telescopic tube 61 will engage the side edges of 
the upper leaf 82 of the clevis 80, causing the cross arm 36 to be moved 
back to a right angle attitude with respect to the tow bar 35, thereby 
causing the ball hitch 136 to be positioned along the centerline of the 
tow bar 35. 
As illustrated in FIG. 11, a pair of sling support bars can be mounted to 
cross arm 36. In the embodiment illustrated, the sling support bars 139 
and 140 are mounted to the sleeve members 92 and 93, and each includes a 
bracket 141 at its lower end for slidably mounting about a sleeve member. 
Each bracket 141 is approximately C-shaped, and includes overhanging end 
portions 142 through which a retaining pin 144 is inserted so as to lock 
the bracket to the sleeve member. The brackets 141 hold the sling support 
bars parallel to each other in upwardly inclined attitudes, and the upper 
end portions 145 of each sling support bar is rounded. 
Flexible sling straps 146 are connected to each sling support bar. Each 
strap 146 has one of its ends rigidly connected to the rounded upper 
portion 145 of a sling support bar, and the free end of each sling strap 
has connected to it a connector hook 148 which defines a slot 149 for 
receiving a chain link or other flexible connector means 150 (FIG. 12). 
With this arrangement, the sling support bars 139 and 140 can be moved 
toward or away from each other by moving the sleeve elements 92 or 93 
toward or away from each other or by mounting the sling support bars at 
different positions on the sleeve members. When the cross arm 36 is moved 
to the ground surface, the free ends of the sling straps 146 can be moved 
beneath a vehicle to be towed (FIG. 12), and a chain or other flexible 
connector can be connected to the frame of the vehicle and inserted into 
the slot 149 of the connector 148, thereby connecting the sling straps 146 
to the vehicle. When the cross arm 36 is raised, the sling straps 146 will 
lift the bumper or other forwardly-protruding elements of the vehicle, 
thereby raising the front of the vehicle from the ground surface (FIG. 
12). 
As illustrated in FIG. 10, the parallel linkage is constructed so that the 
tow bar 35 will be inclined downwardly at a 2.degree. angle from the 
horizontal when the tow bar is moved to its lowermost position, and will 
be inclined upwardly at a 7.degree. angle with respect to the horizontal 
when moved to its uppermost position. With this arrangement, the cross arm 
36 can be positioned relatively low with respect to the tow truck so that 
the cross arm can reach downhill from the tow truck. When raised, the 
cross arm lifts the forward portion of the automobile high enough so that 
the automobile can extend over the rear portion of the tow truck (FIG. 1). 
The hydraulic cylinders function as power means for raising and lowering 
the tow bar and for distending the telescopic sections of the tow bar. 
These hydraulic cylinders are controlled in a conventional manner by a 
pump and valves and by control levers located internally of the cab of the 
tow truck, with a duplicate set of control levers located at the rear, low 
profile portion of the tow truck. This is conventional in the art. 
While the wheel lift tow assembly has been disclosed as including sleeve 
members 92 and 93 movable along the end portions of the cross arm 36, the 
assembly can be constructed without the sleeve members, with the L-shaped 
wheel support brackets 112 being slidably inserted through a socket 
opening 105 mounted directly to the end of a cross arm, and with the sling 
support bars 139 and 140 mounted directly on the cross arm. 
In order to stabilize the cross arm 36 with respect to the tow bar 35, a 
spring-ball assembly 131 (FIG. 14) is mounted through the cross arm to 
engage the detent 133 in the rounded protrusion 81 of the tow bar. This 
forms a yieldable connection between the cross arm and the tow bar to hold 
the cross arm from freely pivoting about the upwardly extending axis 89. 
As illustrated in FIGS. 13 and 14, the cross arm 36 can be mounted on a 
double pivot to tow bar 35, about an upwardly extending axis 89 as 
previously described, and also about a longitudinal axis 156 that is 
coextensive with the tow bar. As illustrated in FIG. 14, boss 160 replaces 
the ball spring assembly and is mounted to the base 161 of clevis 80 and 
extends through opening 162 of cross arm 36. Retaining plate 164 holds the 
cross arm to the bars, so that cross arm 36 is rotatable about 
longitudinal axis 156. Pivot bearing 165 extends vertically through the 
openings of parallel clevis plates 166 and 168, through vertical opening 
169 of the protrusion 81 of inner telescopic tube 63, so that cross arm 36 
is rotatable about vertical axis 89. With this arrangement the cross arm 
can tilt about horizontal axis 156 that normally extends approximately 
longitudinally with respect to the towed vehicle, and can rotate about 
vertical axis 89, and if the towed vehicle and tow truck should become 
tilted with respect to each other, as when moving over a small hill or 
around a sharp turn, the universal connection between the tow truck and 
towed vehicle will tend to avoid any stress forces at the upwardly 
extending axis 89. 
It will be noted that the invention has been disclosed in combination with 
a boom 24 and cable 25 and related elements; however, the boom, cable and 
related elements are not necessary for the operation of the disclosed 
invention, and the tow truck can be constructed and used with the 
disclosed invention and without the boom, cable, etc. Also, while power 
cylinders 60 and 65 have been disclosed as the means for moving the cross 
arm toward and away from the forward end of the tow bar and tow truck, and 
for raising and lowering the cross arm with respect to the tow truck, 
other manually operated or power assist means can be utilized for this 
function if desired. Also, while a parallel linkage has been disclosed as 
the means for raising and lowering the tow bar and crossarm, other means 
can be used for this purpose, if desired. For example, FIG. 15 illustrates 
a tow bar assembly 180 pivotably mounted to the tow truck on a single 
horizontal pivot 181. Actuator arm 182 is rigidly connected at its lower 
end to tow bar assembly 180, and hydraulic cylinder 184 extends between 
the upper portion of actuator arm and the support bracket 185. With this 
arrangement, cylinder 184 functions to tilt tow bar assembly 180 about 
horizontal pivot 181. 
While this invention has been described in detail with particular reference 
to preferred embodiments thereof, it will be understood that variations 
and modifications can be effected within the spirit and scope of the 
invention as described hereinbefore and as defined in the appended claims.