Note: Descriptions are shown in the official language in which they were submitted.
2 ~ 3 6 ~ 1
ROAD VEHICLE HAVING A REAR DUMP BOX
. . _ . _ . . . .
BAC~GROUND OF THE INVENTION
This invention relates to a road vehicle of the
type having a rear dump box. The term "vehicle" herein is
intended to include both a trailer for attachment to a separate
tractor unit or to a vehicle which includes both the tractor
unit and a frame arrangement on which the box is directly
mounted.
Conventionally vehicles of the type having a rear
dump box include a main chassis having a ground wheel assembly
at a rear end connected to the chassis by suitable suspension
arrangement. At the front end, the vehicle can include either
a fifth wheel type hitch for connec~tion to a tractor unit in a
semi trailing system or can include the front wheels of the
tractor unit or can include front wheels which attach by a
hitch arrangement to a separate tractor unit.
Conventionally the chassis includes a pair of
longitudinal beams which connect from the front end of the
vehicle to the ground wheel assembly at the rear end~
The truck box includes a floor which is
horizontal and extends from the front to the rear of the box
and from one side to the other side of the box. Along each
side of the box is provided a vertical side wall. At a front
: ; :
.
2 ~
end of the box is provided a front wall and also a tower
arrangement for receiving the jack by which the front end of
the box can be lifted from the chassis to discharge the load of
a pourable solid material. At the rear end of the box is
provided a tail gate section which includes at least a portion
which can be opened to allow the discharge of the material as
the box is raised. The box is also pivotally mounted at the
rear end to the main chassis to allow the pivotal action to
occur by which the front end is raised for the discharge of the
load.
As the box must, during the discharge process, be
supported upon the jack at the front end and the pivot mounting
arrangement at the rear end, it is necessary that the box is
thus a separate structural element which can accomodate the
forces of the load and properly transmit those forces to the
jack and to the frame at the rear end without bending or
deformation of the box occuring during the di~charge process.
In order -to provide this structural strength,
conventionally the truck box uses the side walls of the truck
box as the main structural member which communicates the forces
longitudinally to the jack at the front end and to the frame at
the rear end. For this purpose, the floor includes a plurality
of transverse beams or ribs which extend ~rom one side wall to
~ ~ .
. . . : :
. : ~ ' - ' ; : ' '
the opposed side wall and are generally provided as shallow
beams attached to the flat sheeting forming the floor itself.
The side walls are -then formed with a structural box section at
the bottom edge extending along the full length of the box. In
addition~ a second box section is provided at the top of the
side wall and then a plurality of vertical ribs are provided in
the side wall to connect the structural beams at the side wall
and to form a truss arrangement. The tower or coupling
arrangement between the front end of the box and the jack then
communicates forces from the top of the jack to the sidewalls.
Similarly at the rear end of the box forces are communicated
from the side walls inwardly to the pivotal mounting
arrangement on the frame of the vehicle.
In addition longitudinal beams are provided along
the length of the floor at positions spaced inwardly of the
side walls and extending the full length of the box from the
front wall to the tailgate section. However these beams are
designed so that they are incapable of receiving the full load
from the box since the main structural member of the box is
constituted by the side walls. The longitudinal beams are
therefore present to communicate or spread forces from the
floor to more than one of the transverse beams. Thuæ an
impacting load dropped onto the floor at a particular location
-, . .
~.' . ' . ~ . ~
: . ,; :.
: ',':, :, : '
2 ~ 6 ~
along the length of the floor is communicated into forces
applied to a number of the transverse beams through the
longitudinal beams, thus reducing the strength necessary for
each of the transverse beams individually.
This conventional arrangement is widely used and
has been accepted as the norm for many years.
SUMMARY OF THE INVE:NTION
It is one object of the present invention to
prcvide an improved structural arrangement for the box of a
road vehicle of the type having a rear dump box.
According to the first aspect of the invention
there is provided a road vehicle having a rear dump box,
comprising a box for receiving and containing a load of a
pourable solid material including a horizontal floor, two
vertical side walls each extending along a respective side of
the floor from a front end of the floor to a rear end of the
floor, a front end wall at a front ~nd of the box upstanding
from the floor and connected to the side walls, a rear tail
gate section of the box upstanding from the floor at the rear
end of the box and connected across the side walls, the tail
gate section including a portion thereof which can be opened to
allow discharge therethrough of the pourable material from the
box, a support assembly for the box including a ground wheel
..~;
.: ~ ,. .
.' ~' ' ;''~ .
2 ~
assembly arranged ad]acent said rear end of the floor of the
box for supporting the rear end, the ground wheel assembly
having ground wheels for engaging the ground and frame means
connected to the ground wheel assembly, the frame means
including pivot mounting means for engaging the box adjacent
said rear end for allowing pivotal movement of the box relative
to the support assembly about a horizontal axis transverse to
the length of the box such that the front end of the box can be
raised relative to the rear end to cause said discharge of the
pourable material, the support assembly further including a
front support portion for engaging and supporting the box at
the front end wall, the front support portion including jack
means connected between the front support portion and the box
at the ~ront end wall of the box for raising the front end of
the box to cause said discharge, the box incl~lding connecting
means for engaging said jack means and receiving force
therefrom for raising said front end, the improvement wherein
the box comprises two longitudinal parallel beams extending
from the front end of the box to the rear end of the box
underneath the f loor at a portion spaced inwardly of the side
walls and attached to the floor, the longitudinal beams being
shaped and arranged to constitute the main longitudinal
structural members of the box, first beam means connected to
5 -
.. . . .. ..
~ . . .
, :' ~ ' ~ ' ' ' ,
said longitudinal beams for transmitting loading from thelongitudinal beams to said connecting means such that force
from the jack when raising the front end of the box is
transmitted to said longitudinal beams, two side beams each
arranged longitudinally along a respective ona of the side
walls at a position thereon spaced upwardly of the floor, those
portions of the side walls between the front end and the rear
end consisting solely of longitudinally smooth surfaces so as
to be free from vertically extending structural ribs, and that
portion of the floor between the front end and the rear end
consisting solely of a flat sheet of metal extending across the
box from one side wall to the opposed side wall and supported
by said longitudinal beams so as to be free of transversely
extending structural ribs.
According to a second aspect of the invention
there is provided a road vehicle having a rear dump box,
comprising a box for receiving and containing a load of a
pourable solid material including a horizontal floor, two
vertical side walls each extendin~ along a respective side of
the floor from a front end of the floor to a rear end of the
floor, a front end wall at a front end of the box upstand.ing
from the floor and connected to the side walls, a rear tail
gate section of the box upstanding from the floor at the rear
, ' ' ~` ,.,
-
.
end of the box and connected across the side walls, the tail
gate section including a portion thereof which can be opened to
allow discharge therethrough of the pourable material from the
box, a support assembly for the box including a ground wheel
assembly arranged adjacent said rear end of the floor of the
box for supporting the rear end, the ground wheel assembly
having ground wheels for engaging the ground and frame means
connected to the ground wheel assembly, the frame means
including pivot mounting means for engaging the box adjacent
said rear end for allowing pivotal movement of the box relative
to the s~pport assembly about a horizontal axis transverse to
the length of the box such that the front end of the box can be
raised relative to the rear end to cause said discharge of the
pourable material, the support assem~ly ~urther including a
front support portion for engaging and supporting the box at
the front end wall, the front support portion including jack
means connected between the front support portion and the box
at the front end wall of the box for raising the front end of
the box to cause said discharge, the box including connecting
means for engaging said jack means and receiviny force
therefrom for raising said front end, the improvement wherein
the box comprises two longitudinal parallel beams extending
from the front end of the box to the rear end of the box
underneath the floor at a position spaced inwardly of the side
walls and attached to the floor, the longitudinal beams being
shaped and arranged to receive the majority of the vertical
loading of ths box thereupon, beam means connected to said
longitudinal beams for transmitting said loading from the
longitudinal beams to said connecting means such that force
from the jack when raising the front end of the box is
transmitted to said longitudinal beams, that portion of the
floor between the front end and the rear end being
substantially free of transversely extending structural ribs,
and means on each of said side walls for preventing outward
bowing of the side walls in response to force from the load.
According to a third aspect of the invention
there is provided a road vehicle having a rear dump box,
comprising a box for receiving and containing a load of a
pourable solid material including a horiæontal floor, two
vertical side walls each extending along a respective side of
the floor from a front end of the floor to a rear end of the
floo~, a front end wall at a front end of the box upstanding
from the floor and connected to the side walls, a rear tail
gate section of the box upstanding from the floor at the rear
end of the box and connected across the side walls, the tail
gate section including a portion thereof which can be opened to
:',. ' ' ., ,"' '' , '
~ , .
2 ~
allow discharge therethrough of the pourable material from the
box, a support assembly for the box including a ground wheel
assembly arranged adjacent said rear end of the floor of the
box for supporting the rear end, the ground wheel assembly
having ground wheels for engaging the ground and frame means
connected to the ground wheel assembly, the frame means
including pivot mounting means for engaging the box adjacent
said rear end for allowing pivotal movement of the box relative
to the support assembly about a horizontal axis transverse to
the length of the box such that the front end of the box can be
raised relative to the rear end to cause said discharge of the
pourable material, the support assembly further including a
front support portion for engaging and supporting the box at
; the front end wall, the front support portion including jack
means connected between the front support portion and the box
at the front end wall of the box for raising the front end of
the box to cause said discharge, the box including connecting
means for engaging said jack means and receiving force
therefrom for raising said front end, the improvement wherein
the box comprises two longitudinal parallel beams extending
from the front end of the box to the rear end of the box
underneath the floor at a position spaced inwardly of the side
walls and attached to the floor, the longitudinal beams being
.
.~": . " :' '
: ~ -
: ' ~
2 ~
shaped and arranged to constitute the main longitudinal
struc~ural members of the box, beam means connected to said
longitudinal beams for transmitting said full loading from the
longitudinal beams to said connecting means such that force
from the jack when raising the front end of the box is
transmitted to said longitudinal beams, two side beam means
each arranged longitudinally along a respective one of the side
walls at a position thereon spaced upwardly of the floor, the
floor being formed and arranged such that forces thereon from
the load are primarily applied to said longitudinal beams and
being substantially free from transverse structural members
transmitting forces transversely to said side walls.
One or more embodiments of the i~vention will now
be described in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
; Figure 1 is a side elevational view of a semi
trailer including a liftable load carrying box according to the
present invention~
Figure 2 is a cross sectional view along the
lines 2-2 of Figure 1 with the main frame of the trailer
omitted from the illustration of the box for convenience.
Figure 3 is a cross-sectional view along the
lines 3-3 of Figure 1.
-- 10 --
'. :- : ` '
.
, .
2 ~
Figure 4 is a cross sectional view alony the
lines 4-4 of Figure 3.
In the drawings like characters of reference
indicate corresponding parts in the different figures.
DETAILED DESCRIPTION
The trailer shown in Figure 1 comprises a truck
box generally indicated at 10 mounted upon a frame generally
indicated at 11. The frame 11 is shown only schematically as
this is of a conventional natureO
The frame 11 includes an elongate frame structure
extending along the full length of the trailer having at a
forward end a king pin arrangement 12 again of conventional
nature for attachment to the fifth wheel of a tractor unit.
The king pin includes a transverse plate 13 and a downwardly
extending pin 14 for engagement with the coupling slot of the
fifth wheel of the tractor.
At the rear end of the frame 11 is provided a
ground wheel a~sembly generally indicated at 14 including two
axles 15 and 16 each of which carries a suitable number of
ground wheels 17 for supporting the ground wheel assembly in
movement across the road surface. A construction of the ground
wheel assembly is shown only schematically and this will of
course include the necessar-y suspension arrangements and other
: : : .
:: : .. ., ,, . . :
: ~ . :, ... . :
. :. .: ,
,.. .. . . ..
': . ` ' ~
2 ~ 6 ~ :
conventional systems necessary for a trailer, which are of
course well known to one skilled in the art.
The main fra~e 11 further comprises a pair of
longitudinal beams shown best in Figure 3 and indicated at 18
and 19 respectively. The beams are shown as box beams but any
suitable frame structure is possible. The beams can be
interconnected by suitable transverse elements (not shown) to
hold the longitudinal frame structurally rigid.
At the rear of the beam 18 and 19 is a transverse
support assembly generally indicated at 20 defining a
transverse pin 21 to which the box is pivotally mounted for
lifting action about the transverse pin 21 in conven~ional
manner. The ~tructure of the support assembly 20 is again
shown only schematically as this can vary according to design
requirements and is well known to one skilled in the art.
At the forward end of the longitudinal beams 18
and 19 just rearward of the king pin assembly 12 is provided a
support cradle generally indicated at 22 for the lower end of a
jack 23. Generally the jack 23 will comprise a multi stage
hydraulic cylinder actuable to raise the upper end of the jack
to lift the forward end of the box in a disharge action. The
cylinder is again only shown schematically as the details of
this will be apparent to one skilled in the art. It suffice to
- 12 -
say that the cylinder includes a transverse pin 24 at a lower
end for pivotal attachment to the cradle 22 so that the lower
end of the cylinder can pivot forwardly and rearwardly to
accomodate the arcuate movement of the front end of the box.
In addition the cylinder 23 includes a transverse pin 25 at an
upper end for connection to the box as described hereinafter
~lthough the frame structure described above is -
shown in relation to a trailer, it will be appreciated that the
same frame structure can be directly attached to a tractor unit
at the forward end or can include front ground wheels coupled
to a steering hitch so that the frame forms part of a pup
trailer. ~:~
Turning now to the structure of the box, the main
detail of the structure is shown best in Figure 2. The box
structure thus comprises a floor 30, a front wall 31, two side
walls 32 and 33, a rear tail gate section 34 (Figure 1) and a
pair of longitudinal support beams 35 and 36.
The floor 30 consists solely of a flat sheet of
steel or other suitable metal without the addition of
transverse supporting ribs, which are conventional in the
manufacture of boxes of this nature. The floor sits directly
on top of the beams 35 and 36 each of which extends along the
full length of the floor from the front wall 31 to the tailgate
- ~ .:: , - ,
.~
' ' '.' '
: ~ : .
2 ~
section 34. Each of the beams comprises a flanged beam sec-tion
generally of an "I-beam" or "Z-beam" shape including a top
flange 37, a bottom flange 38 and a single vertical web 39.
The top horizontal flange 37 is formed integrally with the web
39 by bending the plate from which the web is formed. The
bottom horizontal flange 38 is welded along the bottom edge of
the web 39 at an intermediate point 40 so that an inner edge 41
of the web 38 projects inwardly from the inside surface of the
web 39 and the outer edge 41 of the web 38 projects outwardly
from the outer surface of the web 39. However the intermediate
point 40 is offset so that only a short portion of the flange
project~ inwardly. As shown in Figure 3, the shape allows the
box beam 18 to pass inside the edge ~1 of the bottom flange 38
but with the top edge of the box beam engaging the underside of
the top flange 37 to allow the top flange 37 to rest on the top
of the box beam when in a normal lowered condi~ion of the box
on the frame.
As shown in Figure 1, a central portion of the
vertical web 39 of the beam 35, the portion being indicated at
39A, is of increased height. The central or intermediate
portion 39A is located forwardly of the wheel assembly and
rearwardly of the tractor unit and is provided to increase the
structural strength of the I-beam members at the central
: ~ ; '.'`
, .: . : ' :`
6 ~ .~
location which is the area which receives the maximum loading
when transmitting forces from the load on the floor forwardly
and rearwardly to the jack at the front and to the support
section 20 at the rear.
The side walls 32 and 33 are identical in
structure so that only one of these will be described. Thus
the side wall 32 is formed of four pieces 43,44,43A,44A. The
first piece 43~ includes a flange portion 45 at an upper end
which turns outwardly at right angles to the vertical height of
the side wall extends substantially vertically downwardly
therefrom. The piece 43 includes a top flange 50 connected to
the flange 45 at a weld line D. The piece 43 then turns
vertically downwardly at a position 51 and inwardly at a
position 52 the bottom edge of which is welded to the bottom of
the piece 43A and at a weld line B. The piece 43 further
includes a portion 53 3xtending dc,wnwardly from the weld line
and forming a straight line with the piece 43A thus defining
the inside wall of the side wall 32. The piece 44 commences at
a weld line A on the outside o the porton 53 and extends
outwardly and downwardly therefrom in a position 55, vertically
downwardly in a posi-tion 56 and downwardly and inwardly in a
position 57. The bottom of the portion 57 is welded at a weld
line C to the bottom edge of the portion 53. The pie~e 44
15 -
,' .~ . ': ' .: .'i .
:- ' '~ '
2 ~
further includes a vertical portion 46 which extends downwardly
from the weld line C and includes an outturned portion 47 which
is inclined outwardly and downwardly from the portion 46. From
the outer edge of the inclined portion 47 is provided a
vertical portion 48 which extends downwardly into contact with
the outer edge of the floor 30 with a flange 49 turned at right
angles to the portion 48 to tuck underneath the floor 30. The
portion 48 is then welded to the floor along a weld line E.
The fourth piece 44A is welded at a weld line E
to the bottom edge of the vertical portion 46 and is inclined
downwa dly and inwardly to a weld line G at the floor 30.
Thus the portions 50, 51 and 52 o:E the outer sheet together
with the vertical portion of the inner piece 43 form a
fabricated box beam at the top edge of the side wall. The box
beam is completed by welding along the line indicated at B and
D.
A second box beam underneath the upper most box
beam is defined by the inclined wall portion 55 of the piece
44, the vertically depending portion 56, and the inwardly and
downwardly inclined portion 57. The portions 55, 56 and 57
cooperate with the vertical portion of the sheet 43 to form a
hollow box beam completed by welding along the lines indicated
at A and C. A third box beam is provided by the portion
- 16 -
6 ~ .~
47,48,44A and the outer part of the floor 30 connected at the
weld lines E, F and G.
It will be noted that the side wall is formed
without any vertical struts, beams or ribs or other vertical
structural members so that the only vertical element of the
side wall is defined by the sheet forming part of the side wall
itself which are reinforced by the longitudir,ally extending box
bea~s. Thus the side wall is formed only by smoothly
longitudinally extending wall portions.
In order to prevent twisting of the beams 35 and
36, a plurality of interconnecting struts 58 are provided at
spaced positions along the length of the beams. Each strut 58
extends from a pad 59 on an upper surface of the flange 38 or
on the web 39 (not shown) to a pad 60 attached to the underside
of the floor 30. These struts are only limited in number and
in one example three such struts can be provided at spaced
positions along the length of each of the beams. The struts
are not intenaed to communicate forces from the outer edge of
the floor to the beam but are simply there to prevent the lower
edge of the beam tending to twist inwardly or outwardly under
bending loads.
Turning now to Figures 3 and 4, the forward end
of the box is shown in more detail and particularly the forward
' .
2 ~ $ ~ ~
end of the beams 35 and 36 is shown including the bottom flange
38, the upstanding web 39 and the top flange 37.
To the top flange of each of the beams 35 and 36
is welded a respective one of a pair of upstanding beams 61 and
62. Each of the beams 61 and 62 comprises a box heam or open
channel or otehr member capable of transmitting longitudinal
tension forces, attached at its lower end to the flange 37 and
extending generally upwardly therefrom to a coupling section
generally indicated at 63 for receiving the upper end of the
jack 23. Each beam 61, 62 is inclined upwardly and forwardly
as shown in Figure 4 and is also inclined inwardly as shown in
Figure 3. On the inside surface of each of the beams 61 and 62
is attached the front wall 31 so that the front wall 31 is
similarly inclined as shown in Figure 4~ Across the top of the
beams 61 and 62 and the front wall 31 is attached a front cap
64 which includes a horizontal flange 65, a front depending
flange portion 66 and a rear depending flange portion 67 which
extends downwardly and then forwardly. The interconnection
between the beam 61, 62 and the cap 64 provide a structural
strength for receiving the transverse pin 25 which extends
through an upper part of the beams 61 and 62 to communicate the
force thereto from the jack 23. The jack 23 is thus located
outside khe box on the forward side of the front wall 31. The
- 18 -
:' '' ',
2~6~1
upward and forward inclination of the front wa~l provides an
attractive aerodynamic appearance and the beams 61 and 62
provide a simple attractive structure receiving and housing the
jack 23. As shown in Figure 1, the upper part of the jack can
be encased within a depending shroud 67 to prevent the
penetration of moisture or other contaminants.
The longitudinal strength for the box for
communication of forces from the load both to the jack at the
forward end and to the pivot mounting 20 at the rearward end is
provided mainly by the I-beams 35 and 36 so that the I beams
constitute the main longitudinal structural members of the box.
The floor includes no transverse elements communicating forces
to the side walls and it is not intended that the side walls
act, as in the conventional construction, to communicate the
majority of the forces in the longitudinal direction. The
I-beams are thus selected according to good enginQering
principles to provide suff icient strength to accomodate the
bending forces applied to the box by the load across the
forward and rearward ends as described above. The floor
therefore does not need transverse elements transmitting forces
outwardly to the sides. The floor is thus constituted solely
by a single sheet which is sufficient to carry the loads and to
transmit those loads inwardly from the side edges to the
-- 19 --
.. , :. ., .
2~6~
I-beams 35 and 36. The side walls do however pre~ent the
otusrmost edges of the floor from bending downwardly and thus
do receive some of the vertical loading from the floor. In one
practical example, this proportion of the loading may be 2S% of
the total loading. This loading is transmikted back to the
jack at the forward end by the front sheet 31 and to the
transverse beam 20 at the rear end.
The side walls include no vertical structural
members and include basically a box beam along the upper edge
which is provided for the primary reason of preventing outward
bowing of the sides due to the outward pressure from the load
when stacked above the floor to a height adjacent the top of
the side walls.
As the forces from the load are thus transmitted
along the I-beams to the forward end, the upright beam 61 and
62 thus are connected directly to the I-beams and communicate
the forces upwardly therefrom to the coupling means or cradle
at the top of the jack. The forces from the jack can be
communicated outwardly to the sides of the box through the
sheet 31 since the sides are used for the transmission of only
a smaller proportion of the bending loads~
The structure described above has the following
advantages relative to conventional truck box structures
- 20 -
. :.
. . .
2 ~
described hereinbefore in the preamble.
1. The loads are transmitted more efficiently
using less materials thus significantly decreasing the weight
of the box as a whole and significantly reducing the cost of
manufacture due to the reduction in materials.
2. The absence of transverse members in the
floor prevents the floor from forming depressions or bowed
sections between each transverse member in the next (known as
"washboarding"). These depressions in the floor are known to
inhibit discharge of the ~aterials from the box since the floor
is no longer a smooth channel from which the rnaterial can
readily flow. In the present dev:ice any such bowing of the
floor will form three troughs longitudinally in the floor which
will not inter~ere with the sliding action of the material
during discharge.
3. The absence of vertical ribs on the outside
surface o the side walls significantly improves the
aerodynamic effect of the truc~ box. Thus the conventional
vertical ribs of the truck box significantly interfere with the
smooth flow of air along the sides of the truck box and this is
prevented in the present design by the longitudinally smooth or
flat surfaces which form the side walls without vertical
restriction to flow.
- 21 -
.: , ,:. : , :,:: ., .~
2~8~6~
4. The appearance of the truck box is
significantly improved due to the smooth sides and due to the
inclined front wall and the neat and simple appearance oP the
structural members at the front end.
5. The absence of transverse members both across
the floor and vertically of the side walls allows a
significantly easier cleaning of the box to maintain the
attractive appearance.
Since various modifications can be made in my
invention as hereinabove described, and many apparently widely
different embodiments of same made within the spirit and scope
of the claims without departing from such spirit and scope, it
is intended that all matter contained in the accompanying
specification shall be interpreted as illustrative only and not
in a limiting sense.
- 22 -
:, .
,
