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Claims  |
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What is claimed is:
1. A shiftable undercarriage for use in supporting the deck of a trailer
movable between a horizontal position and an angled position, the
undercarriage comprising
an elongated undercarriage frame having forward and rear ends;
a first axle supported on the frame adjacent the forward end and extending
transverse to the frame;
a second axle supported on the frame adjacent the rear end and extending in
a direction parallel to the first axle;
a plurality of wheels rotatably supported on each of the axles; and
load distribution means mounted on the undercarriage frame for evenly
distributing the weight of the deck between the first and second axles,
the load distribution means including a floating link assembly having
opposing first and second support arms and an intermediate link, each
having first and second ends, the second ends of the support arms
including bearing means adapted to engage the main deck for transmitting
weight of the deck to the support arms,
the undercarriage frame including a pair of horizontal pivot axes on which
the support arms are supported, the pivot axes each extending in a
direction parallel to the direction in which the first axle extends and
defining with the other axis a midpoint halfway therebetween which is
vertically aligned with a midpoint defined halfway between the axles, the
intermediate link being connected between the first ends of the support
arms in a direction substantially perpendicular to the horizontal pivot
axes and being vertically offset from the pivot axes, the intermediate
link further being movable relative to the undercarriage frame for
transmitting the weight of the deck equally between the support arms
regardless of the angle of the deck and for evenly distributing the weight
of the deck between the axles of the undercarriage.
2. A trailer comprising:
an elongated deck having a forward end and a rear end;
an undercarriage including an undercarriage frame and a plurality of
ground-engaging wheels rotatably mounted on the undercarriage frame;
undercarriage shifting means for selectively shifting the undercarriage
along the elongated deck; and
deck support means mounted on and being movable with the undercarriage for
supporting the deck on the undercarriage, the deck support means including
a pair of lift arms connected between the elongated deck and the
undercarriage frame, each of the lift arms including a first end connected
to the undercarriage frame for pivotal movement about a horizontal axis
and a second end provided with bearing means for supporting the main deck,
and lifting means for lifting the elongated deck assembly relative to the
undercarriage by pivoting the lift arms relative to the undercarriage, the
lifting means including retaining means extending between the first ends
of the lift arms at a position vertically spaced from the pivotal
connections of the link arms to the undercarriage frame for retaining the
lift arms in any given position relative to the undercarriage regardless
of the position of the undercarriage relative to the elongated deck, and
being operable independently of the undercarriage shifting means for
lifting the deck relative to the undercarriage without simultaneously
shifting the undercarriage along the deck.
3. A trailer comprising:
an elongated deck having a forward end and a rear end;
an undercarriage including an undercarriage frame and a plurality of
ground-engaging wheels rotatably mounted on the undercarriage frame;
undercarriage shifting means for selectively shifting the undercarriage
along the elongated deck; and
deck support means mounted on and being movable with the undercarriage for
supporting the deck on the undercarriage, the deck support means including
a pair of lift arms connected between the elongated deck and the
undercarriage frame, each of the lift arms including a first end connected
to the undercarriage frame for pivotal movement about a horizontal axis
and a second end provided with bearing means for supporting the elongated
deck and lifting means for lifting the elongated deck relative to the
undercarriage, the lifting means being operable independently of the
undercarriage shifting means for lifting the deck relative to the
undercarriage without simultaneously shifting the undercarriage along the
deck;
the deck support means including link means extending between the first
ends of the lift arms at a position vertically spaced from the pivotal
connections of the link arms to the undercarriage frame for transferring
forces between the lift arms so that any load applied to one of the lift
arms is transferred through the lift arm link means to the other lift arm
and is distributed equally to the pivotal connections of the link arms.
4. The trailer as set forth in claim 3, wherein the link means includes a
fluid actuated extendable link and the lifting means includes actuation
means for actuating the extendable link to pivot the lift arms about their
horizontal axes to adjust the height of the deck relative to the
undercarriage.
5. The trailer as set forth in claim 2, wherein the elongated deck includes
a forward deck, a swing deck having a front end pivotally connected to the
forward deck and a rear end, and an elongated main deck having an anterior
end pivotally connected to the rear end of the swing deck, the trailer
further comprising:
deck angle adjustment means for adjusting the relative positions of the
decks between a roading position in which the main deck is disposed in a
horizontal plane and an unloading position in which the main deck is
angled relative to the forward deck.
6. A trailer comprising:
an elongated deck including a forward deck, a swing deck having a front end
pivotally connected to the forward deck and a rear deck and a rear end,
and an elongated main deck having an anterior end pivotally connected to
the rear end of the swing deck;
an undercarriage including an undercarriage frame and a plurality of
ground-engaging wheels rotatably mounted on the undercarriage frame;
undercarriage shifting means for selectively shifting the undercarriage
along the elongated deck;
deck support means mounted on and being movable with the undercarriage for
supporting the deck on the undercarriage, the deck support means including
lifting means for lifting the elongated deck assembly relative to the
undercarriage, the lifting means being operable independently of the
undercarriage shifting means for lifting the deck relative to the
undercarriage without simultaneously shifting the undercarriage along the
deck; and
deck angle adjustment means for adjusting the relative positions of the
decks between a roading position in which the main deck is disposed in a
horizontal plane and an unloading position in which the main deck is
angled relative to the forward deck, the deck angle adjustment means
including
a timing link having a first end pivotally mounted on the elongated main
deck and a second end remote from the first end, the timing link being
pivotally connected to the forward deck at a point intermediate the first
and second ends, and
a fluid actuated cylinder assembly including a cylinder and a piston, one
of the cylinder and piston being pivotally connected to the swing deck and
the other of the cylinder and piston being pivotally connected to the
second end of the timing link so that actuation of the cylinder assembly
results in movement of the swing deck and main deck relative to the
forward deck.
7. The trailer as set further in claim 5, further comprising hitch means
for permitting the trailer to be pivotally connected to the towing
vehicle, the hitch means including a lower plate having a hitch pin
adapted to engage the fifth wheel and an upper plate connected to the
forward deck, the upper plate being pivotally connected to the lower plate
for pivotal movement relative to the lower plate about a horizontal axis
to permit the forward deck to be tilted away from the main deck to
increase the angle between the main deck and the forward deck when the
trailer is in the unloading position.
8. A trailer for use in connection with the towing vehicle having a fifth
wheel, the trailer comprising:
a forward deck;
a swing deck having a front end and a rear end, the front end being
pivotally connected to the forward deck;
an elongated main deck having an anterior end pivotally connected to the
rear end of the swing deck;
deck angle adjustment means for adjusting the relative positions of the
decks between a roading position in which the elongated main deck is
disposed in a horizontal plane and an unloading position in which the main
deck is angled relative to the forward deck, the deck angle adjustment
means including
a timing link having a first end pivotally mounted on the elongated main
deck and a second end remote from the first end, the timing link being
pivotally connected to the forward deck at a point intermediate the first
and second ends, and
a fluid actuated cylinder assembly including a cylinder and a piston, one
of the cylinder and piston being pivotally connected to the swing deck and
the other of the cylinder and piston being pivotally connected to the
second end of the timing link so that actuation of the cylinder assembly
results in movement of the swing deck and main deck relative to the
forward deck;
an undercarriage supporting the elongated main deck and being shiftable
longitudinally along the main deck, the undercarriage including a
plurality of ground engaging wheels; and
hitch means for permitting the trailer to be pivotally connected to the
towing vehicle, the hitch means including a lower plate having a hitch pin
adapted to engage the fifth wheel and an upper plate connected to the
lower plate for pivotal movement relative to the lower plate about a
horizontal axis to permit the forward deck to be tilted away from the main
deck to increase the angle between the main deck and the forward deck when
the trailer is in the unloading position.
9. The trailer as set forth in claim 8, wherein the undercarriage includes
an undercarriage frame, the trailer further comprising deck support means
mounted on the undercarriage for supporting the deck on the undercarriage,
the deck support means including a pair of lift arms connected between the
main deck and the undercarriage frame, each of the lift arms including a
first end connected to the undercarriage frame for pivotal movement about
a horizontal axis and a second end provided with bearing means for
supporting the main deck.
10. The trailer as set forth in claim 8, wherein the deck support means
includes link means extending between the first ends of the lift arms at a
position vertically spaced from the pivotal connections of the link arms
to the undercarriage frame for transferring forces between the lift arms
so that any load applied to one of the lift arms is transferred through
the lift arm link means to the other lift arm and is distributed equally
to the pivotal connections of the link arms.
11. The trailer as set forth in claim 10, wherein the link means includes a
fluid actuated extendable link and actuation means for actuating the
extendable link to pivot the lift arms about their horizontal axes to
adjust the height of the deck relative to the undercarriage.
12. A trailer comprising:
a forward deck;
a swing deck having a front end pivotally connected to the forward deck and
a rear end;
an elongated main deck having a forward end pivotally connected to the rear
end of the swing deck;
an undercarriage supporting the elongated main deck and being shiftable
longitudinally along the main deck, the undercarriage including a
plurality of wheels; and
deck angle adjustment means for adjusting the relative positions of the
decks, the deck angle adjustment means including
a timing link having a first end pivotally mounted on the elongated main
deck and a second end remote from the first end, the timing link being
pivotally connected to the forward deck at a point intermediate the first
and second ends, and
a fluid actuated cylinder assembly including a cylinder and a piston, one
of the cylinder and piston being pivotally connected to the swing deck and
the other of the cylinder and piston being pivotally connected to the
second end of the timing link so that actuation of the cylinder assembly
results in movement of the swing deck and main deck relative to the
forward deck.
13. The trailer as set forth in claim 12, wherein the undercarriage
includes an undercarriage frame, the trailer further comprising deck
support means mounted on the undercarriage for supporting the deck on the
undercarriage, the deck support means including a pair of lift arms
connected between the main deck and the undercarriage frame, each of the
lift arms including a first end connected to the undercarriage frame for
pivotal movement about a horizontal axis and a second end provided with
bearing means for supporting the main deck.
14. The trailer as set forth in claim 13, wherein the deck support means
includes link means extending between the first ends of the lift arms at a
position vertically spaced from the pivotal connections of the link arms
to the undercarriage frame for transferring forces between the lift arms
so that any load applied to one of the lift arms is transferred through
the lift arm link means to the other lift arm and is distributed equally
to the pivotal connections of the link arms.
15. The trailer as set forth in claim 14, wherein the link means includes a
fluid actuated extendable link and actuation means for actuating the
extendable link to pivot the lift arms about their horizontal axes to
adjust the height of the deck relative to the undercarriage.
16. The trailer as set forth in claim 2, further comprising a bumper
assembly supported on the elongated deck and being movable longitudinally
between the forward and rear ends of the deck with the undercarriage when
the undercarriage is shifted by the undercarriage shifting means, the
bumper assembly remaining substantially stationary relative to the
elongated deck during operation of the lifting means.
17. The trailer as set forth in claim 2, wherein the elongated deck
includes a plurality of cross-support members extending beneath the deck,
the lifting means being operable to lift the deck relative to the
undercarriage from a lowered position in which the wheels of the
undercarriage are disposed partially above the cross-support members and a
raised position in which the wheels are disposed completely below the
cross-support member.
18. The trailer as set forth in claim 2, further comprising undercarriage
guide means for guiding the undercarriage and deck support means as they
are shifted along the elongated deck.
19. The trailer as set forth in claim 18, wherein the undercarriage guide
means includes means for retaining the undercarriage and deck support
means on the elongated deck regardless of the orientation of the elongated
deck relative to the undercarriage and regardless of whether the wheels of
the undercarriage are in engagement with the ground. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to trailers and, more particularly,
to a trailer for loading and transporting large specialized vehicles such
as farm and construction machinery, buses and tractors, and for use in
other industrial applications.
2. Discussion of the Prior Art
It is known to provide a trailer having a shiftable undercarriage which
includes a pair of tracks on the bed and a pair of ramps for raising the
bed relative to the undercarriage when the latter is shifted from a
roading position to provide sufficient spacing between the bed and the
undercarriage for clearance of the bed understructure during movement of
the undercarriage. Examples of such a construction are illustrated in U.S.
Pat. Nos. 4,125,198 and 4,231,710 to Landoll.
It would be desirable to further improve the construction and operation of
these known devices by reducing the roading height of a trailer to permit
the trailer to be used in transporting taller machinery than was permitted
to be transported with previous trailers. In addition, it would be
advantageous to provide a trailer having a still lower angle of loading
than presently exists on known trailers so as to increase the utility of
the trailer and to permit loading of machinery having very little ground
clearance such as buses, asphalt laydown equipment, fork lifts and aerial
lift equipment.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a trailer having a deck
which may be tilted relative to the ground by any angle between a first
minimum load angle and a second maximum angle, such that the deck is
movable within a wide range of positions for loading, unloading and ground
dumping cargo therefrom.
It is a further object of the invention to reduce the weight of a trailer
while increasing the capacity such that the trailer is capable of use in
transporting cargo of greater weight than would be allowed with heavier
trailers.
Another object of the invention is to provide a trailer including a
mechanism for independently lifting the trailer deck relative to the
undercarriage in order to permit the deck to be raised to the level of a
loading dock for easy loading and unloading therefrom and to permit
adjustment of the deck height at any position of the undercarriage without
affecting the carriage position along the length of the deck.
The present invention also has as an object, that of providing a mechanism
which evenly distributes loads between the axles of the undercarriage
regardless of the longitudinal position of the undercarriage or of the
tilt angle of the deck. This mechanism also provides for maximum axial
stability of the load on the disclosed trailer.
A trailer constructed in accordance with the present invention includes an
elongated deck having a forward end and a rear end, and an undercarriage
including an undercarriage frame and a plurality of ground-engaging wheels
rotatably mounted on the undercarriage frame. Undercarriage shifting means
are provided for selectively shifting the undercarriage along the
elongated deck, and deck support means are mounted on the undercarriage
for supporting the deck by the undercarriage. The deck support means
includes lifting means for lifting the elongated deck assembly relative to
the undercarriage. This lifting means is operable independently of the
undercarriage shifting means for lifting the deck relative to the
undercarriage without simultaneously shifting the undercarriage along the
deck.
In accordance with another aspect of the invention, a trailer for use in
connection with a towing vehicle having a fifth wheel includes hitch means
for permitting the trailer to be pivotally connected to the towing
vehicle. The hitch means includes a lower plate having a hitch pin adapted
to engage the fifth wheel and an upper plate connected to the forward
deck. The upper plate is pivotally connected to the lower plate for
pivotal movement relative to the lower plate about a horizontal axis to
permit the forward deck to be tilted away from the main deck to increase
the angle between the main deck and the forward deck when the trailer is
in the unloading position. The plates may be secured to the trailer in any
of a number of positions such that the pin is properly positioned to
provide a desired swing clearance and weight transfer to the prime mover.
According to a further aspect of the invention a trailer includes deck
angle adjustment means for adjusting the relative positions of a plurality
of decks. The deck angle adjustment means includes a timing link having a
first end pivotally mounted on the main deck and a second end remote from
the first end, the timing link being pivotally connected to the forward
deck at a point intermediate the first and second ends. A fluid actuated
cylinder including a cylinder and a piston is also provided, with one end
of the cylinder and piston being pivotally connected to the swing deck and
the other end of the cylinder and piston being pivotally connected to the
second end of the timing link so that actuation of the cylinder assembly
results in movement of the swing deck and main deck relative to the
forward deck.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
A preferred embodiment of the invention is discussed in detail below with
reference to the attached drawing figures, wherein:
FIG. 1 is a side elevational view of a towing vehicle and trailer in a
roading position;
FIG. 2 is a side elevational view of the towing vehicle and trailer in a
minimum angle loading position:
FIG. 3 is a side elevational view of the towing vehicle and trailer in a
high angle position;
FIG. 4 is a fragmentary side elevational view of a trailer raised to the
level of a loading dock;
FIG. 5 is a fragmentary side elevational view of the forward and swing
decks of the trailer and the rear end of the towing vehicle;
FIG. 6 is a fragmentary top plan view of the structure shown in FIG. 5;
FIG. 7 is a fragmentary irregular vertical sectional view of the structure
shown in FIG. 5, with the trailer in the roading position;
FIG. 8 is a fragmentary irregular vertical sectional view of the structure
shown in FIG. 5, with the trailer in the high angle position;
FIG. 9 is a rear elevational view of the forward deck with the swing deck
removed to illustrate the hydraulic cyclinders mounted in the forward
deck;
FIG. 10 is a fragmentary longitudinal vertical sectional view of the hitch
assembly at the front end of the forward deck;
FIG. 11 is a fragmentary vertical cross-sectional view taken along line
11--11 of FIG. 10;
FIG. 12 is a longitudinal vertical sectional view of the main deck and
undercarriage of the trailer with the deck shown in a lowered roading
position;
FIG. 13 is a longitudinal vertical sectional view of the main deck and
undercarriage of the trailer with the deck shown in a raised
undercarriage-shifting position;
FIG. 14 is a longitudinal vertical sectional view of the main deck and
undercarriage of the trailer with the deck shown in an angled position
relative to the undercarriage;
FIG. 15 is a top plan view of the undercarriage including a portion of the
structure of the main deck;
FIG. 16 is a vertical cross-sectional view of the main deck and
undercarriage taken intermediate the lifting arms of the deck lifting
assembly and showing the deck in a raised position relative to the
undercarriage; and
FIG. 17 is a fragmentary top plan view of the main deck and undercarriage
showing the hydraulic cylinder assembly used for shifting the
undercarriage longitudinally along the main deck.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A trailer constructed in accordance with the present invention is
illustrated in FIGS. 1-3, hitched to a towing vehicle having a fifth
wheel. In FIG. 1, the trailer 20 is illustrated in a roading position for
transporting a load such as farm machinery, truck tractors, buses and the
like between two destinations. The trailer 20 includes a forward deck 22
hitched to the towing vehicle 24, an intermediate swing deck 26, and a
main deck 28 including an undercarriage 30 positioned adjacent the rear
end thereof on which the trailer is supported for transportation.
The undercarriage 30 is constructed to be selectively shiftable relative to
the main deck 28 between the positions shown in FIGS. 1 and 2. In FIG. 2,
the undercarriage 30 is illustrated in the forwardmost position thereof
which permits the rear end of the main deck 28 to be lowered into contact
with the ground while maintaining the lowest possible angle between the
ground and the main deck. A linkage assembly 32, discussed below with
reference to FIGS. 7-9, is provided on the trailer 20 for moving the
forward, intermediate and main decks between the positions shown in FIGS.
1-3, and is actuated during loading to move the intermediate and main
decks to the positions shown in FIG. 2.
A maximum angle position of the trailer 20 is shown in FIG. 3, wherein the
linkage arrangement 32 is actuated to position the intermediate deck 26 in
line with the forward deck 22 so that the main deck 28 is disposed at the
greatest angle possible relative to the ground. The trailer may be moved
to this maximum angle position either when it is desired to unload dead
weight which is not easily removed from the trailer at lower deck angles,
or during loading when it is necessary to lift the main deck during
shifting of the undercarriage 30 from the forward, loading position shown
in FIG. 2, toward the rearward, roading position of FIG. 1.
As discussed below, when the trailer 20 is oriented in the maximum angle
position during a loading operation thereof, the load on the deck 28 is
removed from the undercarriage 30, thus enabling shifting of the
undercarriage toward the rear of the main deck. In addition, a hitch
assembly 34 is provided which permits the forward deck 22 to be tilted
relative to the towing vehicle 24 to further increase the angle between
the main deck 28 and the ground in the maximum angle position. This hitch
assembly 34 is discussed with reference to FIGS. 10 and 11.
In addition to providing the range of angular adjustment of the trailer
decks 22, 26, 28 illustrated in FIGS. 1-3, the decks of the trailer may
also be lifted as a unit relative to the undercarriage 30 to position the
main deck 28 level with a loading dock 36 or other elevated loading or
unloading site. This position of the trailer 20 is shown in FIG. 4, and
the lifting assembly enabling this movement of the trailer is discussed
below with reference to FIGS. 12-16.
The forward and intermediate decks 22, 26 are illustrated in detail in FIG.
5 along with a portion of the main deck 28. As shown in the figure, the
forward deck is a goose-neck shaped deck having a rear end 38 which turns
downward from the upper surface of the deck 22. At the front end of the
forward deck, a winch 40 is preferably provided for pulling heavy dead
loads onto the trailer. Also, the hitch assembly 34, shown in FIG. 7, is
provided at the lower side of the front end for attachment to the fifth
wheel 42 of the towing vehicle 24.
The intermediate swing deck 26, is constructed of a width substantially
equal to the width of the forward deck 22 and is pivotally connected to
the forward deck for movement between the roading position shown in FIG. 5
and the maximum angle position shown in FIGS. 3 and 8. In all positions of
the swing deck 26, the upper surface of the swing deck is disposed
adjacent the upper surface of the forward deck so that a substantially
continuous surface is presented to a load travelling along the trailer
decks.
The rear end of the intermediate deck 26 is also pivotally connected to the
main deck 28 to present a substantially continuous upper surface between
the intermediate and main decks regardless of their relative positions.
Further, the main deck 28 includes a flange or rib 44 extending downward
from each lateral side of the front end of the main deck 28 which engages
a lower upturned edge 46 of the forward deck in the roading position of
the trailer.
The upper surfaces 48, 50, 52 of the forward, intermediate and main decks
are illustrated in FIG. 6. As mentioned, the forward and intermediate
decks 22, 26 are of substantially equal width and are provided with upper
surfaces 48, 50 capable of supporting a desired load thereon. The main
deck is also of a width equal to that of the other decks and includes a
surface 52, e.g. planked wood, which extends over the support structure of
the main deck.
The linkage assembly 32 which moves the three decks into the various
positions shown in FIGS. 1-3 is illustrated in FIGS. 7-9. In FIG. 7, the
linkage assembly 32 is shown in the roading position and includes a
hydraulic cylinder mechanism 54 mounted on the forward deck 22 by a pair
of timing links 56. The cylinder mechanism 54 includes a cylinder 58 and a
piston 60, and is pivotally connected at the piston end thereof to the
intermediate deck 26. The hydraulic cylinder 58 of the mechanism is also
mounted for pivotal movement. However, instead of being mounted directly
to the forward deck 22, the cylinder 58 is mounted in a collar 62 for
pivotal movement on the timing links 56, which are in turn pivotally
supported on the forward deck 22.
As shown, each timing link 56 is a rigid, elongated, irregular-shaped link
having a pair of link segments. The first link segment extends between the
axis about which the link 56 is pivotally supported on the main deck 28
and the axis about which the link is pivotally supported on the forward
deck 22, and the second link segment is defined between the axis about
which the link is supported on the forward deck 22 and the axis about
which the hydraulic cylinder 58 is pivotally supported on the pair of
links 56. In the preferred embodiment, as shown in FIG. 9, two hydraulic
cylinder mechanisms 54 are used in the trailer and two pairs of timing
links 56 support the cylinder mechanisms between the forward and
intermediate decks.
In FIG. 8, the trailer 20 is illustrated in the maximum angle position with
the upper surface 50 of the intermediate deck 26 disposed substantially
coplaner with the upper surface 48 of the forward deck 22. When it is
desired to move the trailer decks toward this high angle position, the
hydraulic cylinder 58 is actuated to move the intermediate deck 26 away
from the lowered position shown in FIG. 7, while at the same time lifting
the forward end of the main deck 28. By mounting the cylinder mechanism 54
on the timing links 56 in the manner shown in the figures, it is possible
to increase the efficiency of the linkage assembly 32 since during
elongation of the mechanism 54, the upward movement of the piston 60
relative to the cylinder 58 raises the intermediate deck 26 and the
downward movement of the cylinder 58 and collar 62 lifts the forward end
of the main deck 28. Further, due to the provision of the hitch assembly
34, which permits pivotal movement of the forward deck 22 relative to the
towing vehicle, it is possible to further increase the angle between the
forward and main decks in the maximum angle position so as to increase the
angle between the main deck 28 and the ground.
The hitch assembly 34 is shown in detail in FIG. 10, and includes a lower
hitch plate 64 pivotally connected along a front edge thereof to an upper
hitch plate 66 attached to the forward deck 22. The lower hitch plate 64
includes a pin 68 welded or otherwise attached thereto extending beneath
the plate for engagement with the fifth wheel 42 of the towing vehicle 24,
as shown in FIG. 7. A chain 70 is connected at one end to the lower hitch
plate 64 and extends through an opening in the upper plate 66 and over a
roller 72. The chain 70 is connected at a second end to a spring assembly
74 which maintains a predetermined tension on the chain so that, when the
hitch assembly is left unattached from the fifth wheel 42 of the towing
vehicle, the lower hitch plate 64 is raised into a storage position in
close contact with the forward deck 22.
As shown in FIG. 11, the upper hitch plate 66 is secured to the forward
deck 22 by a plurality of fasteners 76 passing through both the upper
hitch plate 66 and one of a pair of L-shaped mounting bars 78 provided in
a lower opening of the forward deck 22. The lower hitch plate 64 which is
wider than the upper plate 66, is retained in contact with a pair of
flanges 80 of the support structure of the forward deck which serve as
upper limit stops for the lower hitch plate 66.
When the linkage assembly 32 moves the intermediate deck 26 toward the
maximum angle position shown in FIG. 3, the rear end of the main deck 28
contacts the ground thus limiting further angular movement of the main
deck relative to the horizontally disposed forward deck 22. Thereafter, as
can be seen from FIG. 8, further angular movement of the main deck 28
relative to the forward deck 22 causes the forward deck to tilt relative
to the towing vehicle 24 by pivoting away from the main deck 22 about the
axis defined by the pivot pin 82, shown in FIG. 10, of the hitch assembly
34. Thus, the range of motion of the main deck 22 is not limited to that
which would be permitted if the forward deck were disposed in a fixed
horizontal orientation, but is increased to include all angles between the
low load angle shown in FIGS. 2 and 7, and the large angle illustrated in
FIGS. 3 and 8. In the preferred embodiment, the low load angle is
approximately 6.25 degrees and the maximum unload angle is 10 degrees.
The construction of the main deck 28 is illustrated in FIG. 16, and
includes two main support I-beams 84, 86 extending longitudinally of the
trailer along the lateral sides thereof, and a pair of centrally located
longitudinal I-beams 88, 90 each providing two guide channels in which the
undercarriage 30 and an undercarriage shifting assembly 92 are received. A
number of cross-members 94, 96, shown in FIG. 12, extend between the sides
of the main deck 28. As shown in FIG. 16, these cross-members extend
between the main I-beams 84, 86 and are disposed vertically above the
guide beams 88, 90 so that the guide beams present uncluttered guide paths
to the undercarriage and shifting assemblies. In addition, the main
I-beams 84, 86 are each provided with a bearing flange 98 extending
laterally inward thereof along the bottoms of the cross-members 94, 96,
and defining guide surfaces for engagement by the undercarriage 30.
The shiftable undercarriage 30 of the trailer is shown in various positions
of the trailer in FIGS. 12-15. The construction of the undercarriage 30 is
illustrated in FIG. 12, and includes a frame 100 on which two axles 102
supporting a plurality of wheels 104 are suspended by a pair of air
suspension assemblies 106. Although air-type suspension assemblies are
illustrated in the figures, it is understood that a spring-type suspension
could also be employed without departing from the scope of the invention.
In either case, the wheels 104 and suspension assemblies 106 form a part
of frame 100, and the entire undercarriage 30 is separable from the main
deck 28 of the trailer but for a lifting arm assembly 108 discussed below,
which is pivotally mounted on the undercarriage 30 and which is shiftable
with the undercarriage 30 relative to the main deck 28.
Turning to FIG. 15, the undercarriage frame 100 is illustrated as including
a pair of parallel longitudinal members 110 disposed laterally inward of
the wheels and connected together by transverse cross-members 112. The
open center of the frame 100 forms a cradle in which the lifting assembly
108 is disposed. As shown in FIG. 13, the lifting assembly includes a pair
of channel-shaped lifting arms 114, 116 arranged in opposition to one
another on the undercarriage frame 100, and a hydraulic cylinder mechanism
118 extending between the lifting arms 114, 116. Each of the lifting arms
is pivotally secured between the two longitudinal frame members 110 for
pivotal movement about a pivot axis 120 or 122 which is spaced from the
pivot axis of the other arm in the longitudinal direction of the frame 100
and the two pivot axes 120, 122 are centrally disposed between the axles
102 of the undercarriage 30 such that any load applied to the frame 100 at
the pivot axes 120, 122 is evenly distributed between the two axles 102.
The lifting arms 114, 116 engage the main deck 28 of the trailer through
lateral beams 124, 126 formed at the longitudinally outer ends of the
lifting arms remote from the pivotal connections of the arms to the
undercarriage frame 100. As shown in FIG. 15, the lateral beams 124, 126
of the lifting arms 114, 116 extend between the laterally displaced
I-beams 84, 86 of the main deck 28, and each of the beams includes a pair
of rollers 128 adapted to engage the bearing flanges 98 of the I-beams 84,
86 to permit rolling contact between the lifting arms and the main deck.
By constructing the lifting arms in this manner, the undercarriage 30
moves together with the lifting assembly 108 along the main deck 28 of the
trailer between a rearward roading position shown in FIG. 1 and loading
and unloading positions such as those illustrated in FIGS. 2 and 3. This
shifting of the undercarriage 30 and lifting assembly 108 is possible
regardless of the height of the deck 28 relative to the undercarriage 30
such that the shifting movement of the undercarriage may be carried out
independently of the lifting movement performed by the lifting assembly
108.
Also provided on each of the lateral beams 124, 126 of the lifting arms
114, 116 are a pair of guiding assemblies 130, 132. As shown in FIG. 16,
each one of the assemblies 130 provided on the forward lifting arms 114
includes a bearing pad 134 adapted to travel within one of the spaces
defined by the laterally outer flanges of one of the guide beams 88, 90.
In addition, the forward bearing pads 134 are pivotally supported on the
lateral beam 124 of the lifting arms 114 so that the lifting arms may
pivot relative to the pads 134 during relative vertical movement between
the undercarriage 30 and the main deck 28 while retaining the lifting arms
114 in engagement with the main deck 28.
The bearing pads 136 provided on the rear lifting arm 116, illustrated in
FIG. 15, are each mounted on a pad support bar 138 which extends rearward
of the undercarriage 30 to provide a mounting for a tailight assembly 140
including a | | |
