Tag axle system

A tag axle assembly allows auxiliary axle support to a vehicle (12). The assembly includes a support frame (24) having a pair of vertical supports (26) connected to the load bed subframe (14), a cross beam (58) connects the supports (26). An axle engaging assembly (66) including an auxiliary axle (70) is pivotable with respect to the frame (24) and cross beam (58) for pivoting the auxiliary wheels (22) between engaged and unengaged positions. Pivot plates (80) are connected to the axle (70) and are pivoted by an actuator (94) between a generally horizontal position in the engaged position and a near vertical position in the unengaged position. The auxiliary axle (70) includes torque arms (72) connected thereto for receiving the wheels (22) for pivoting with the axle (70). The vertical supports (26) are comprised of a pair of triangular plates (32, 33) enclosing the actuator (94).

TECHNICAL FIELD 
The invention relates to a tag axle system for selectively providing an 
auxiliary, ground engaging axle to allow additional support in load 
bearing vehicles and to allow retraction to a stored, unengaged position. 
BACKGROUND ART 
Tag axle systems are known in which an auxiliary axle with wheels attached 
thereto is moved to its stored, unengaged position and lowered in an 
engaged load bearing position to provide auxiliary axle and wheels for a 
load bearing vehicle. The tag axle must be stable and positionable for 
ground engagement, and movable to a second stored or transport position. 
In the transport position, the extra or auxiliary wheels should not 
interfere with the other functions of the vehicle. 
One such tag axle system is illustrated in U.S. Pat. No. 4,146,243, issued 
Mar. 27, 1979 in the name of Sims. This patent discloses a linkage tag 
axle system wherein a power actuator rotates the linkage and a beam to 
bring the wheels into ground engaging position and a second power actuator 
pivots the beams upwardly to raise the wheels and tire set. 
A simplified suspension system is illustrated in U.S. Pat. No. 3,743,315, 
issued Jul. 3, 1973 in the name of Bilas. This system discloses an 
auxiliary wheel and axle assembly for a trailer vehicle. A semi-elliptic 
spring positioned transversely of the vehicle is secured thereto and to 
the wheels and axle assembly. The spring lifts the assembly from a road 
surface. Air bags positioned between the wheel and axle assembly and the 
vehicle permit the wheel and axle assembly to be lifted from the road 
surface by the semi-elliptic spring or engaged on the road surface in a 
weight carrying relation to the trailer vehicle when the air bags are 
inflated. 
SUMMARY OF THE INVENTION 
The invention includes a tag axle assembly adapted to selectively provide 
additional support for a load bearing vehicle. The assembly comprises a 
support frame adapted to be fixedly connected to a vehicle for supporting 
a pair of auxiliary wheels. Engaging means is operatively connected to the 
support frame and the auxiliary wheels for moving between a retracted 
position removing the auxiliary wheels from ground level and an extended 
position extending the auxiliary wheels to ground level. Control means is 
operatively connected to the engaging means for selectively controlling 
the retraction and extension of the engaging means. The control means 
includes actuator means operatively connected between the support frame 
and the engaging means for moving the engaging means. The assembly is 
characterized by the support frame including housing means for containing 
the actuator means and supporting the engaging means. 
The invention also includes the support frame including a pair of vertical 
supports having upper and lower integral ends for connection to the 
vehicle at the upper end. The upper end has a width greater than the lower 
end. The engaging means includes longitudinal pivot means pivotally 
connected to the lower end of the support member and having a first end 
adapted to be connected to a wheel and a second end, and a pivot point 
between the first and second ends for connection to the support member for 
pivoting between the engaged position and the non-engaged position with 
the first end aligned with the support member. 
The invention also includes the engaging means including a longitudinal 
pivot plate extending from the support member toward the rear wheels for 
pivoting between a first position with the pivot plate substantially 
horizontal and the wheels in contact with a road surface, and a second 
position with said pivot plate substantially vertical end the wheels 
raised out of contact with a road surface.

DETAILED DESCRIPTION OF THE EMBODIMENT 
A tag axle assembly is generally shown at 10 in FIGS. 1-4. The tag axle 
assembly 10 is adapted to selectively provide auxiliary support or 
suspension to a load bearing vehicle 12 having a vehicle frame and a 
tilting carrier or load bed with bed subframe 14. The load bearing vehicle 
12 with bed subframe 14 is commonly known in the art and exemplified in 
U.S. Pat. No. 5,133,633, issued Jul. 28, 1992. The tag axle assembly 10 is 
located behind the rear vehicle wheel 18 of the vehicle 12, between the 
rear vehicle wheel 18 and the rear end 20 of the vehicle 12. 
The assembly 10 includes a pair of auxiliary wheels 22 which are 
selectively engaged and disengaged in a ground support position for 
providing auxiliary load bearing support to the vehicle frame and the 
tilting load bed subframe 14. In the preferred embodiment, the assembly 10 
is fixedly mounted to the bed subframe 14. 
The tag axle assembly 10 includes an axle support frame 24 adapted to be 
fixedly connected to the tilting load bed subframe 14. The support frame 
24 includes a pair of vertical supports 26 each having upper 28 and lower 
30 ends. The vertical supports 26 are connected to the load bed at the 
upper end 28 thereof. 
Each of the vertical supports 26 generally comprise a pair of spaced apart, 
triangular parallel plates 32, 33 connected to one another at their upper 
ends 28 or triangle base thereof by an upper panel 34. The sides 36, 38 of 
the triangular plates 32 are connected to one another at a portion thereof 
by support side panels 40, 42. The panels 34, 40, 42 are generally welded 
to the plates 32, 33. 
Mounting brackets 44 are fixedly connected to the upper panels 34 for 
subsequent connection to the load bed 14. The mounting brackets 44 connect 
the vertical supports 26 perpendicular to the load bed 14. The upper panel 
34 includes a series of apertures 46 therein for connection to the 
mounting bracket 44. Each mounting bracket 44 comprises an L-shaped plate 
extending the length of the base 28 of the triangle support 26 and upper 
panel 34. A first, horizontal side 48 of the bracket 44 includes apertures 
50 therein for aligning with the apertures 46 of the upper panel 34 so as 
to receive fasteners 52 to connect the bracket 44 to the supports 26 
through the apertures 46, 50. The second, vertical leg 54 of the bracket 
44 includes several horizontal slots 56 therein provided for welding to 
the load bed subframe 14. 
A structural cross beam 58 is fixedly connected or welded between the 
interior plates 33 of the vertical supports 26 in perpendicular relation 
thereto near the lower end or vertex 30 thereof. A reinforcing corner arm 
59 is connected at the intersection between the interior plates 32 of the 
vertical supports 26 and the cross beam 58 extending to and welded to the 
upper panel 34, and includes a bend 60 therein. The cross beam 58 
generally comprises an L-shaped configuration as best illustrated in FIG. 
4. 
Each of the plates 32, 33 of the vertical support 26 form support weldments 
62 at the lower end 30 which extend from and below the cross beam 58 and 
are integral with the plates 32, 33. The support weldments 62 include 
apertures 64 therein. 
The assembly 10 includes engaging means 66 operatively connected to the 
support frame 24 and the auxiliary wheels 22 for moving between an 
extended, engaged position with the auxiliary wheels 22 contacting a road 
surface (FIG. 1), and a retracted, non-engaged position with the auxiliary 
wheels 22 a road surface supporting the load bed 14 (FIG. 4). 
The engaging means 66 includes axle means 68 extending between the pair of 
wheels 22 and pivotally connected to the support frame 24 for pivoting 
between the engaged and non-engaged positions. The axle means 68 includes 
a longitudinal axle 70 extending between the supports 26. The axle 70 
generally comprises a commonly available longitudinal axle of the type 
rubber torsion suspension axle. 
The axle means 68 also includes torque arm means 72 connected to the ends 
of the axle 70. The torque arm means 72 includes first 74 and second 76 
longitudinal ends. The torque arm means 72 is operatively secured to the 
axle 70 at the first end 74 and is secured to the auxiliary wheel 22 at 
the second end 76 for pivoting the axle 70 with the torque arms 72 
substantially horizontal when the assembly 10 is in the engaged position. 
The torque arm means 72 includes a wheel pin or spindle 78 extending 
outwardly from the second end 76 for supporting the wheel 22 thereon. The 
torque arm means 72 comprises a longitudinal, substantially flat, 
rectangular plate. 
The engaging means 66 also includes pivot plate means 80 having first 82 
and second 83 ends. The pivot plate means 80 is connected between a pair 
of the plates 32, 33 of the vertical supports 26 and is connected to the 
axle 70 at its first end 82. The pivot plate means 80 is also connected to 
the vertical supports 26 at a central pivot point between the first and 
second ends 82, 83 for pivoting the axle 70. The second ends 83 of the 
pivot plate means 80 are connected to one another by a bushing 84 
therebetween. 
The pivot plate means 80 generally comprises a pair of spaced, longitudinal 
pivot plates 86, 87 connected to each of the vertical support plates 32, 
33. The pivot plates 86, 87 are connected within and between the 
respective pairs of support weldments 62. The first inner pivot plate 86 
is adjacent the support weldment 62 adjacent the inner plate 33. The outer 
pivot plate 87 is connected adjacent the support weldment 62 adjacent the 
outside plate 32. The plates 86, 87 include an aperture 88 at their pivot 
point for receiving a pivot pin 90 which extends between and through the 
pivot plates 86, 87 and through the apertures 64 of the support weldments 
62 for connecting the pivot plates 86, 87 with the frame 24. 
The assembly 10 also includes actuator means 92 operatively connected to 
the support frame 24 and the engaging means 66 for selectively moving the 
engaging means 66 between the non-engaged position and a maximum, engaged 
position. The actuator means 92 generally includes a hydraulic actuator 
94. The actuator 94 extends between the plates 32, 33 of the vertical 
support 26 and from one corner 96 of the triangle base 28 to the bushing 
84 of the pivot plates 82, 83. The hydraulic actuator 94 includes a first 
end 98 connected to the forward corner 96 of the base 28 of the support 26 
via a pin 100. A second, retractable end 99 of the actuator 94 is 
connected to the bushing 84 of the pivot plate means 80. More 
particularly, the second end 99 of the actuator 94 is welded to the 
bushing 84. 
Therefore, it can be seen that as the actuator 94 moves between its 
extended position or ground engaging position, the torque arms 72 are in a 
generally horizontal position. As the actuator 94 retracts, the second end 
83 of the pair of pivot plates 86, 87 is raised thereby rotating the axle 
70 and first end 82 of the pivot plates 86, 87 to a lower position thereby 
raising the second end 76 of the torque arm 72 to raise the wheels 22. 
When the actuators 94 are extended, the axle 70 rotates with the support 
weldments 62 allowing the wheels 22 to contact the road. 
In operation, FIG. 4 illustrates the assembly 10 in its stored or 
unextended position. In this position, the actuator means 92 is retracted 
which pivots the pivot plates 86, 87 to an almost vertical position which 
in turn pivots and pulls up the pivot plates 86, 87 to raise the auxiliary 
wheels 22. It should be understood that each of the actuator means 94 is 
actuated concurrently and simultaneously in the same manner such that the 
axle means 68 remains horizontal at all times through the while pivoting 
movement. The torque arm 72 is offset approximately 22.degree.-30.degree.. 
However, the invention is not limited to these offsets. From the pivot 
plates 86, 87 when in the unengaged position, which is characteristic of 
common axle performance. For actuation to its extended or engaged position 
as illustrated in FIG. 1, the actuator means 92 is operated to its 
extended maximum position. This in turn pushes the end 83 of the pivot 
plate means 80 downwardly to a position with the pivot plates 86, 87 
generally horizontal and aligned with the torque arm means 72. The pivot 
plates 86, 87 and actuator 94 are connected and move between each of the 
plates 32, 33 of the vertical support 26. The pivot plates 86, 87 move 
between a generally vertical position in the unengaged position and a 
generally horizontal position in the ground engaging position, as in the 
first embodiment. In this position, the assembly 10 is providing 
additional support to the vehicle 12 and its load bed subframe 14. 
The assembly 10 also includes control means 110 for controlling the 
actuator 94 between the extended and retracted position. The control means 
110 is illustrated in FIG. 5. 
The control means 110 includes a master power switch 112 having an on and 
off position for connecting and disconnecting the vehicle battery power 
114 to the control means 110. The power switch 112 is generally connected 
in the cab 113 of the vehicle 12 to allow disabling of the entire system 
by the operator of the vehicle 12 when not in use and prevent tampering 
with the assembly 10. 
Also included in the cab 113 of the vehicle 12 is a toggle actuating switch 
116 having generally three positions of up, neutral, and down. Actuation 
of the toggle switch 116 to the up position actuates the actuator means 92 
to retract the tag axle assembly 10, and actuation of the toggle switch 
116 to the down position causes the actuator means 92 to extend the tag 
axle assembly 10. Also included is a down indicator light 118 generally 
for illuminating when the tag axle assembly 10 is in the down, extended 
position. Further, there is an up indicator light 120 for indicating when 
the tag axle assembly 10 is in its fully retracted position. 
Also included is a passenger side and driver side control box 122, 123 
located near the tag axle assembly 10 at the load bed external the vehicle 
12. The control boxes 122, 123 also includes toggle switches 124, 125 for 
controlling up and down positions of the tag axle assembly 10, the same as 
the cab toggle switch 116. All of the toggle switches 116, 124, 125 are 
double pole, double throw center off (neutral) switches. A DC hydraulic 
power unit 128 is connected to the switches 112, 116, 124, 125 to control 
the hydraulic power to the actuators 94. 
A pair of pressure switches 130, 131 are connected to the actuator 94 to 
sense the pressure of hydraulic fluid and actuate the appropriate light 
118, 120 when a predetermined pressure is reached. Switch 130 is connected 
in the rod side of the hydraulic manifold to sense when the tag axle 
assembly 10 is up, and switch 131 is connected in the piston side to sense 
when the tag axle assembly 10 is down. 
In operation, it is assumed that the auxiliary of tag axle 10 is in its 
retracted position. Initially, the battery disconnect switch 112 must then 
be returned to the on position. Loading on the load bed 14 occurs with the 
tag axle 10 in its retracted position. The load bed 14 for carrier may be 
tilted to receive a vehicle and then return to its stored position. 
Thereafter, the tag axle 10 may be actuated to the extended position to 
transfer weight to the steering axle. The user holds one the toggle 
switches 116, 124, 125 to the down position which in turn causes the 
actuator means 92 to extend thereby extending the tag axle. Once the 
toggle switches 116, 124, 125 are released, the electric pump is 
disengaged. Verification that the tag axle is in its fully extended 
position can be verified by the down indicator light 118. The tag axle 
must also be retracted before unloading of the load bed. The user merely 
actuates a toggle switch 116, 124, 125 to the up position which causes 
retraction of the actuator means 92 to retract the tag axle. Then 
unloading procedures occur as normal. 
The invention has been described in an illustrative manner, and it is to be 
understood that the terminology which has been used is intended to be in 
the nature of words of description rather than of limitation. 
Obviously, many modifications and variations of the present invention are 
possible in light of the above teachings. It is, therefore, to be 
understood that within the scope of the appended claims wherein reference 
numerals are merely for convenience and are not to be in any way limiting, 
the invention may be practiced otherwise than as specifically described.