Truck trailer sliding bogey

Changing the wheelbase on tractor trailer combinations in an effort to better distribute the cargo load weight has resulted in the use of a sliding bogey from which is suspended the trailer running gear. The sliding bogey is independent from the trailer frame and slides fore and aft along the trailer frame and can be locked into a variety of positions along the trailer frame. Currently available bogey systems utilize sliding members of generally rectangular cross section and are subject to binding both from the build up of road contaminants and the inherent difficulties associated with rectangular sliding mechanisms. A more reliable and substantially sealed sliding system utilizes a pair of generally elongated telescoping tubes, each pair located on either side of the trailer frame with one member of each pair forming an integral part of a sliding bogey while the other member of each pair acts as a support piece for the trailer frame, is fixed to the trailer frame and thus moves with the trailer frame. A plurality of locking pins are used to secure the bogey to the trailer frame in the desired position sufficient to achieve the desired wheelbase.

BACKGROUND--FIELD OF THE INVENTION. 
This invention relates to the field of truck semi-trailers and more 
specifically to mechanisms designed to facilitate the altering of the 
trailer wheel base by altering the linear position of the trailer frame 
running gear relative to the trailer body. 
BACKGROUND--DESCRIPTION OF KNOWN ART 
It has long been understood by long haul truckers and by a variety of 
governmental bodies that the road safety and drivability of the truck 
trailer combination is greatly influenced by the positioning of the 
trailer cargo weight relative to the trailer running gear. In short, for 
optimum and safe performance the cargo weight must be balanced to the 
trailer. 
In an effort to provide a mechanism by which the cargo weight may be 
shifted to achieve balance much inventive ingenuity has been applied 
leading to the development of the "sliding bogey". 
Essentially the sliding bogey consists of a frame, independent from the 
trailer frame, to which is attached the trailer running gear--spring 
shackles, springs, torque arms, axles etc. The bogey frame is free to 
slide fore and aft along either the inside or outside edge of the trailer 
frame thus lengthening or shortening the truck trailer combination 
wheelbase. 
Generally the bogey frame is secured and locked into a single position on 
the trailer frame using a plurality of pins inserted into aligned holes in 
both flames. 
In use, the truck driver first disengages the locking pins and moves the 
truck trailer combination ahead or back--depending upon the desired 
wheelbase; the trailer frame slides upon the bogey frame until the desired 
position is reached and the driver then engages the locking pins to 
maintain this position. 
In practice, however, it is more usual to discover that both frames are 
locked into a single position by accumulation of road dirt and other 
contaminants between the sliding surfaces of the frames thus rendering the 
task of shifting the trailer body difficult and often, time consuming. 
In many cases it is not unusual for the driver to be completely unable to 
shift the trailer thus rendering the truck trailer combination unsafe and, 
in some cases, illegal for road use. 
Not surprisingly then, considerable effort has been expended to ensure a 
good, easily maintainable sliding fit between trailer frame and bogey 
frame is achieved. Unfortunately, the nature of the systems currently in 
use are, by their very nature, utilizing as they do rectilinear members, 
inherently difficult to seal and maintain adequate lubrication. The 
present invention, an embodiment of which is hereinafter described in 
detail, overcomes many of the shortcomings associated with current systems 
by providing a simple, efficient, easily maintainable and to a large 
extent self-sealing sliding mechanism utilizing tubular sliding members 
rather than the traditional rectangular sliding members. 
SUMMARY 
According to one aspect the present invention is a truck trailer sliding 
bogey comprising: 
a first pair of elongated semi-circular tubular sliding means spaced 
parallel to each other and maintained in alignment with each other by 
rigid cross support means; 
a second pair of elongated semi-circular tubular sliding means slidably 
mounted over the first pair of sliding means and free to move fore and aft 
thereupon; 
means for locking the second pair of sliding means at predetermined 
intervals along the surfaces of the first pair of sliding means so that 
the positioning of the second sliding means is adjustable relative to the 
first sliding means; 
means for securing each of the second pair of sliding means to the rear 
undersurface of a truck trailer body; 
means for securing the truck trailer running gear to the rigid cross 
support means; 
means for lubricating the sliding surfaces of each of the first sliding and 
second sliding means; 
means for substantially containing the lubricant within the sliding 
surfaces of the first and second sliding means; and 
means for substantially sealing the sliding surfaces of the first and 
second sliding means against contaminants.

DESCRIPTION 
Refer to FIGS. 1 to 5 
A first bogey frame member 10 is comprised of an elongate rigid tubular 
body 12 having an axial opening along its length and inwardly curving 
lower ends 14. A rigid support beam 16 is integral to the tubular body 12 
and runs the full length of the inner surface of the tubular body 12 and 
extends downward from the tubular body 12 to a distance below the inwardly 
curving ends 14 of the tubular body 12. 
A substantially centrally located first machined groove 18 positioned at 
the topmost point of the outer surface of the tubular body 12 serves as a 
lubrication channel and extends the full length of the tubular body 12. 
A plurality of circumferentially positioned machined grooves 20 intersect 
first machined groove 18 at regular intervals along the outer surface of 
the tubular body 12 thus forming a network of lubrication channels along 
and across the outer surface of the tubular body 12. 
A plurality of through holes 22 of sufficient diameter to accommodate the 
insertion of locking pins 24 are located along the length of the support 
beam 16 substantially equidistant apart at intervals of approximately six 
inches. 
The support beam 16 further incorporates a variety of through holes along 
its surface by means of which the semi-trailer 50 running gear 54 and 
wheels 52 may be suspended. 
A second bogey frame member (not shown) which is essentially a mirror image 
of the first frame member 10 is located parallel to the first frame member 
10 at a distance approximating the width of a typical semi-trailer 50 and 
both the first frame member 10 and its mirror frame are maintained in 
parallel alignment by at least a pair of rigid cross supports 26. 
A first trailer frame 28 support member 30 is comprised of a rigid tubular 
body 32 having an axial opening along the full length of the lower surface 
and having inwardly curving lower ends 34 and of an inside diameter 
sufficient to provide for a sliding clearance fit to the outer surface of 
the first bogey frame 10 tubular body 12. 
A rigid "I" beam member 36 is integral to the first trailer frame 28 
support 30 tubular body 32 and is located substantially centrally to the 
outer surface of the tubular body 32, extends substantially vertically 
thereto, runs the full length of the tubular body 32 and serves as a 
platform upon which is mounted the trailer frame 28. 
A lower section 38 of the trailer frame 28 extends downward such as to 
remain in close proximity to the support beam 16 of the first bogey frame 
member 10; incorporates a plurality of through holes 40 substantially 
equal in diameter to the holes 22 in the bogey frame member 10 and spaced 
apart substantially equal distance as the holes 22 in the bogey frame 
member 10 so that when aligned with the holes 22 in the bogey frame member 
10, the insertion of at least a pair of locking pins 24 secures the bogey 
frame member 10 to the trailer frame 28. 
A second trailer frame 28 support member (not shown) which is essentially a 
mirror image of the first frame 28 support member 30 is located parallel 
to the first support member 30 at a distance approximating the width of a 
typical semi-trailer and both the first support member 30 and its mirror 
support member are maintained in parallel alignment by virtue of mounting 
to the underside of the trailer frame 28. 
Lubricant may be introduced to the sliding surfaces of the tubular bodies, 
12 and 32 respectively by any conventional means such as via grease 
fittings mounted through the trailer frame 28 support 30 tubular body 32. 
A pair of relatively thin flexible strips 42 of uniform wall thickness may 
be mounted to the underside of the inwardly curving ends 34 of the trailer 
frame 28 support member 30 tubular body 32 by any appropriate and 
conventional means such as set screws such that each strip 42 extends 
inwardly from the tubular member 32 and wipes against the wall on either 
side of the first bogey frame 10 support beam 16 thus substantially 
eliminating the ingress of contaminants between the sliding surfaces of 
the bogey frame 10 tubular body 12 and the trailer frame 28 support member 
30 tubular body 32. 
Additionally, a semi-circular wiper pad 44 having an outwardly flared 
wiping edge 46 may be mounted to each end of the bogey frame 10 tubular 
body 12 by any appropriate and conventional means such as a threaded bolt 
48 so that as the trailer frame 28 support member 30 tubular body 32 
slides upon the bogey frame 10 tubular body 12 excess lubricant adhering 
to the inner surface of the support tubular body 32 is wiped inwards and 
thus retained between the sliding surfaces of the tubular bodies, 12 and 
32 respectively. 
It will be understood from the foregoing description and consideration of 
the accompanying drawings that operation of the sliding bogey of the 
present invention is similar to that of the prior art in that locking pins 
24 are first withdrawn from the bogey frame 10 and trailer frame 28 and 
the truck trailer combination moved either forwards or rearwards allowing 
the trailer frame 28 to slide upon the bogey frame 10 by virtue of the 
sliding surfaces formed by the tubular bodies, 12 and 32 respectively. 
Once positioned correctly, the trailer frame 28 is secured to the bogey 
frame 10 by insertion of the locking pins 24. 
Scope 
The preferred embodiment of the present invention as described herein 
provides a simple to operate, reliable and easy to maintain sliding bogey 
to facilitate the adjustment of the wheelbase of tractor/trailer 
combinations by replacing the generally rectangular sliding members of the 
prior art which are known to be particularly prone to contaminant related 
sliding problems, with generally tubular sliding members which are 
inherently easier to seal from contamination and less prone to binding. 
Although the above description contains many specificities these should not 
be construed as limiting the scope of the invention but rather as 
illustrations of a presently preferred embodiment. Thus the scope of the 
invention should be determined by the appended claims and their legal 
equivalents.