Note: Descriptions are shown in the official language in which they were submitted.
CA 02725261 2010-12-14
STEERABLE CONVEYOR
FIELD OF THE INVENTION
The present invention relates to an agricultural conveyor having wheels
which are steerable relative to a frame of the conveyor such that the conveyor
can be
steered relative to a towing vehicle when towing the conveyor, and more
particularly
the present invention relates to a steering mechanism for commonly steering
the
wheels of the conveyor when the conveyor is supported on two laterally opposed
pairs of wheels.
BACKGROUND
Conveyors, and more particularly auger type screw conveyors, are
available in relatively large sizes for agricultural applications. Conveyors
of this type
typically include a tubular housing supported on wheels which are parallel and
spaced
apart from one another on opposing sides of the housing and fixed in
orientation for
rolling movement in the longitudinal direction of the housing so as to be
suitable for
towing by a tractor and the like. Because of the large sizes of some
conveyors, these
conveyors can be very difficult and awkward to navigate during transport.
Some larger agricultural conveyors are supported on first and second
pairs of wheels at respective first and second laterally opposed sides of the
conveyor
frame. In this instance, the wheels of each pair of wheels are longitudinally
spaced at
opposing ends of a walking beam providing some relative suspension between the
wheels. The longitudinally spaced wheels can be even more difficult to
navigate
during transport due to the wheels being restricted from pivoting in
orientation relative
to one another.
Auger moving kits are known, for example a self propelled auger
transport kit available by Wheatheart, but such known systems are typically
very
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limited in size and involve the costly addition of an auxiliary set of wheels
supported
on an auxiliary frame along with an additional motor suitable only for
transport of
smaller agricultural augers. Steering is typically accomplished in a skid
steer
configuration. No means are provided for steering the conveyor relative to a
vehicle
during transport.
Canadian Patent 2,614,538, filed Dec. 10, 2007, by Toews, discloses a
steering mechanism for a conveyor when the conveyor is only supported on two
wheels which are laterally spaced along a common rolling axis. The steering
mechanism in the form described is not readily adaptable to two pairs of
wheels
supported on a walking beam suspension as found on some larger agricultural
conveyors.
Various examples are known for steering the trailing wheels of a vehicle
or a trailer, particularly those with longitudinally spaced pairs of wheels.
Some
examples are disclosed in US Patents 4,286,798 by Butler et al, 5,207,443 by
Mitchell
and 3,930,669 by Kollander et at. None of the examples in the prior art are
suitable
for use on an agricultural conveyor for effectively steering the trailing
movement of the
conveyor relative to the towing vehicle.
SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided a steerable
conveyor for use with a towing vehicle in which the towing vehicle comprises a
vehicle
frame supported for rolling movement in a forward direction on vehicle wheels
which
are steerable relative to the vehicle frame, the conveyor comprising:
a conveyor housing for conveying material therein in a longitudinal
direction from an inlet end to an outlet end;
a conveyor frame supporting the conveyor housing thereon;
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a first pair of wheels and a second pair of wheels supporting laterally
opposed first and second sides of the conveyor frame respectively thereon for
rolling
movement along the ground;
each wheel of each pair of wheels comprising a steerable wheel which
is pivotal about a respective upright axis relative to the conveyor frame;
a hitch connector arranged for connection to the towing vehicle such
that the conveyor frame is arranged to be pivotal relative to the towing
vehicle about a
vertical steering axis of the hitch connector and such that the conveyor frame
is
arranged to be movable together with the towing vehicle for rolling movement
in the
forward direction;
a steering mechanism arranged to pivot each of the steerable wheels of
both pairs of wheels together relative to the conveyor frame in a common
direction of
rotation such that the conveyor housing is arranged to be steerable relative
to the
towing vehicle about the vertical steering axis when the conveyor housing is
towed for
rolling movement in the forward direction with the towing vehicle; and
a controller arranged to control the steering mechanism of the steerable
wheels.
By providing a steering mechanism which commonly steers all of the
wheels, each about their own axis, effective steering of an agricultural
conveyor
relative to a towing vehicle can be accomplished even when the conveyor is
supported on two pairs of wheels such as a walking beam suspension for
example,
The controller allows the steering mechanism to control the path that the
conveyor
follows relative to the towing vehicle even when the conveyor wheels trails
behind the
towing vehicle by a considerable distance as in a larger screw auger or belt
conveyors. The independent controller of the steering mechanism allows the
conveyor
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to be readily navigated around various obstacles by also following a narrower
or wider
path than the towing vehicle if desired.
Preferably the two wheels of the first pair of wheels are spaced apart in
the longitudinal direction at the first side of the conveyor frame and the two
wheels of
the second pair of wheels are spaced apart in the longitudinal direction at
the second
side of the conveyor frame.
The steering mechanism preferably comprises an actuator associated
with each steerable wheel in which the actuators are arranged to be commonly
controlled by the controller.
In some embodiments, the actuator associated with each steerable
wheel may comprise an electrically driven actuator.
More preferably, the actuator associated with each steerable wheel
comprises a linear hydraulic actuator.
When provided in combination with the towing vehicle in which the
towing vehicle comprises a controllable hydraulic output, the hydraulic
actuators are
preferably commonly connected to the controllable hydraulic output.
All of the hydraulic actuators of the steerable wheels may be connected
in series with one another such that each actuator comprises a rephasing port
in
connection with another one of the other actuators.
Typically each actuator comprises a retraction port arranged to retract
the actuator when receiving hydraulic fluid therein and an extension portion
arranged
to extend the actuator when receiving hydraulic fluid therein. In a re-phasing
configuration, preferably two of the actuators comprise first actuators which
are
arranged to rotate the associated steerable wheels in a first direction about
their
respective upright axes when the first actuators are extended and two of the
actuators
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comprise second actuators which are arranged to rotate the associated
steerable
wheels in a second direction about their respective upright axes opposite to
the first
direction when the second actuators are extended. In this instance, the
extension
port of each first actuator is preferably hydraulically connected to the
extension port of
5 a respective one of the second actuators and the retraction port of one of
the second
actuators is preferably hydraulically connected to the retraction port of one
of the first
actuators such that all of the actuators are hydraulically connected in series
with one
another in the re-phasing configuration. In this instance, the actuators
associated with
all of the steerable wheels may be identical in size and configuration
relative to one
another.
When the actuator associated with each steerable wheel comprises a
cylinder end and a piston end, each actuator is preferably coupled to the
conveyor
frame at the cylinder end and is preferably coupled to the respective
steerable wheel
at the piston end.
When the upright axes of the two steerable wheels of the first pair of
wheels are longitudinally spaced apart in a first common plane and the upright
axes of
the two steerable wheels of the second pair of wheels are longitudinally
spaced apart
in a second common plane, preferably the first and second common planes are
oriented parallel to the longitudinal direction.
The two wheels of the first pair of wheels may be supported at
longitudinally opposed ends of a respective beam extending in the longitudinal
direction at the first side of the conveyor frame and the two wheels of the
second pair
of wheels may be supported at longitudinally opposed ends of a respective beam
extending in the longitudinal direction at the second side of the conveyor
frame. In
this instance, the two wheels of the first pair of wheels may be offset in
laterally
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opposed directions from the respective beam and the two wheels of the second
pair
of wheels may be offset in laterally opposed directions from the respective
beam.
When the steering mechanism comprises an actuator associated with
each steerable wheel, each actuator is preferably supported on the respective
beam
laterally opposite to the associated steerable wheel.
The frame may further comprise a pair of walking beams supporting the
conveyor frame on the two pairs of wheels respectively in which the walking
beams
extending generally in the longitudinal direction and are spaced apart from
one
another in a lateral direction oriented transversely to the longitudinal
direction at
opposing sides of the conveyor frame. In this instance, each walking beam may
be
supported on a respective one of the pairs of wheels such that the wheels are
supported at longitudinally opposing ends of the walking beam, and each
walking
beam may be pivotally coupled to the conveyor frame for relative pivotal
movement
about a walking beam axis oriented generally in the lateral direction.
When provided in combination with the vehicle frame, preferably the
controller is arranged to control the steering mechanism of the steerable
wheels of the
conveyor independently of the steering of the vehicle wheels relative to the
vehicle
frame.
According to a second aspect of the present invention there is provided
a steerable conveyor in combination with a towing vehicle in which the towing
vehicle
comprises a vehicle frame supported for rolling movement in a forward
direction on
vehicle wheels which are steerable relative to the vehicle frame, the conveyor
comprising:
a conveyor housing for conveying material therein in a longitudinal
direction from an inlet end to an outlet end;
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a conveyor frame supporting the conveyor housing for rolling movement
on respective steerable wheels which are pivotal about respective upright axis
relative
to the conveyor frame;
a hitch connector for connecting the conveyor housing to the towing
vehicle such that the conveyor housing is pivotal relative to the towing
vehicle about a
vertical steering axis of the hitch connector and such that the conveyor frame
is
movable together with the towing vehicle for rolling movement in the forward
direction;
a steering mechanism arranged to commonly pivot the steerable wheels
together relative to the conveyor frame such that the conveyor housing is
steerable
relative to the towing vehicle about the vertical steering axis when the
conveyor
housing is towed for rolling movement in the forward direction with the towing
vehicle;
a controller in the towing vehicle arranged to control the steering
mechanism of the steerable wheels of the conveyor independently of the
steering of
the vehicle wheels relative to the vehicle frame.
One embodiment of the invention will now be described in conjunction
with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic top plan view of the wheels of the steerable
conveyor oriented in the forward direction of the towing vehicle.
Figure 2 is a schematic top plan view of the steerable wheels of the
conveyor shown commonly pivoted in a first lateral direction relative to the
forward
direction of the towing vehicle which is opposite to the direction of the
steerable
wheels of the vehicle which are steered towards a second lateral direction in
relation
to the forward direction of the vehicle.
Figure 3 is a perspective view of one of the walking beams at one side
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of the conveyor frame with one of the steerable wheels shown removed from its
hub.
Figure 4 is a schematic view of the hydraulic circuit connecting the
actuators of the steering mechanism according to a preferred embodiment.
In the drawings like characters of reference indicate corresponding parts
in the different figures.
DETAILED DESCRIPTION
Referring to the accompanying figures there is illustrated a steerable
conveyor generally indicated by reference numeral 10. The conveyor 10
typically
comprises an agricultural conveyor, for example a large screw type auger
conveyor or
a belt conveyor.
The conveyor is typically transported by connection to a towing vehicle
12, for example an agricultural tractor, a highway truck, or other implement
handling
equipment supported on its own vehicle wheels for rolling movement along the
ground
in a forward working direction in normal use. The vehicle 12 is also steerable
and
movable in an opposing rearward direction as in most convention wheeled
vehicles.
In a preferred embodiment, the towing vehicle comprises a hydraulic output 13
which
is controllable by an operator of the vehicle to control steering of the
conveyor relative
to the towing vehicle. The hydraulic output 13 is controllable independently
of the
vehicle steering control which controls steering of the vehicle wheels
relative to a
frame of the vehicle so that steering of the conveyor relative to the towing
vehicle is
independent of the steering of the vehicle wheels relative to the vehicle
frame. In the
instance of a highway truck or other implement handling equipment, the
hydraulic
output 13 may be provided by an auxiliary hydraulic power unit which is
powered by
the vehicle electrically so that the output 13 can be similarly controlled
independently
by the operator of the vehicle.
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The conveyor 10 of the illustrated embodiment comprises an elongate
tubular housing 14 supporting a screw auger or belt therein which is arranged
to
convey material in a longitudinal direction of the housing from an inlet end
16 to an
outlet end 18 of the housing when the screw auger is rotated about a
longitudinal axis
thereof or the belt is rotated in the usual manner. A conveyor frame 20
supports the
housing 14 at an upward angle or inclination from the inlet end 16 to the
outlet end 18
thereof.
The conveyor frame 20 includes a cross bar 22 which spans in a lateral
direction between opposing first and second sides of the conveyor frame so as
to be
oriented generally perpendicularly to the longitudinal direction. A plurality
of support
arms 24 extend upwardly from the cross bar in the form of an adjustable
linkage
which supports the housing at various inclinations about the frame. In
particular, the
linkage formed by the support arms is arranged for movement relative to the
housing
between a working position extending at an upward inclination from the inlet
end to
the outlet end and a transport position in which the housing is nearer to
horizontal
than the working position. A hitch connector 26 is located at the inlet end of
the
housing and is connected to the conveyor frame either directly by hitching
arms or
through connection to the housing. The hitch connecter 26 is arranged for
connection
to the hitch of a towing vehicle such that the conveyor frame is arranged to
be pivotal
relative to the towing vehicle about a vertical steering axis of the hitch
connector and
such that the conveyor frame is arranged to be moveable together with the
towing
vehicle for rolling movement in the forward direction.
The cross bar 22 of the conveyor frame is carried on a first walking
beam 28 and a second walking beam 30 which are oriented generally in the
longitudinal direction so as to be parallel and laterally spaced apart from
one another
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at opposing first and second sides of the conveyor frame respectively. Each
walking
beam is pivoted at a central location in the longitudinal direction on a
respective one
of the two opposing ends of the cross bar 22 such that the two walking beam
are
pivotal relative to the frame about a common horizontal walking beam axis
extending
5 in the lateral direction.
Each walking beam comprises upper and lower frame members 32
extending in the longitudinal direction above and below the walking beam axis
respectively so as to be joined with one another at the longitudinally opposed
ends of
the beams.
10 The first walking beam is supported for rolling movement on the ground
on a first pair of steerable wheels 34 coupled to the opposing ends of the
beam
respectively. Similarly the second walking beam 30 is supported for rolling
movement
on the ground on a second pair of steerable wheels 36 supported on the
longitudinally
opposed ends thereof.
On both walking beams, the steerable wheel nearest to the inlet end of
the conveyor housing is off-set laterally outward to an outer side of the
respective
beam. Alternatively the steerable wheel nearest to the outlet end of the
conveyor
housing is off-set laterally inwardly towards an inner side of the beam such
that the
two steerable wheels nearest to the outlet end are closer together than the
two
steerable wheels at the inlet end. This arrangement accommodates for support
arms
extending towards the hitch connector at the inlet end of the housing. The two
steerable wheels for each beam are thus laterally off-set in opposing
directions from
the beam.
Each steerable wheel is supported on the beam by a respective steer
arm 38 which is oriented in the lateral direction so as to be perpendicular to
the
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longitudinal direction when the respective wheel is oriented for rolling
movement in
the longitudinal direction. The steering arm is pivotally coupled to the end
of the
respective walking beam about an upright axis which defines a steering axis of
the
steering arm and respective steerable wheel pivotal therewith relative to the
walking
beam of the conveyor frame. Each pair of wheels of each walking beam are thus
pivoted about respective axis located at the ends of the beam in a generally
common
vertical plane such that the first and second common vertical planes are
parallel and
laterally spaced apart at opposing sides of the conveyor frame.
A first portion of each steering arm extends in the lateral direction from
the beam in the direction of off-set of the respective wheel supported on the
end
thereof. In addition to the first portion spanning towards the respective
wheel
supported thereon, each steering arm also includes a second portion
diametrically
opposite the first portion supporting the wheel thereon such that the second
portion
projects generally laterally in the opposing direction from the respective
beam for
connection to a common steering mechanism arranged to pivot each of the
steerable
wheels of both pairs of wheels together relative to the conveyor frame in a
common
direction of rotation. The conveyor frame and housing supported thereon are
thus
arranged to be steerable relative to the towing vehicle about the vertical
axis of the
hitch connector when the conveyor housing is towed for rolling movement in the
forward direction with the towing vehicle.
The steering mechanism comprises an actuator 40 associated with each
of the four steerable wheels. Each actuator 40 comprises a linear hydraulic
actuator
having a cylinder end and an opposing piston end which is arranged to be
extended
and retracted in relation to the cylinder end for varying the length of the
actuator in a
linear direction. A cylinder portion of each actuator includes a retraction
port 42 and
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an extension port 44. The retraction port serves to retract the piston end
into the
cylinder end when receiving a flow of hydraulic fluid under pressure therein.
Alternatively, the extension port is arranged to extend the piston end away
from the
cylinder end when receiving a flow of hydraulic fluid under pressure therein.
In the illustrated embodiment, all of the actuators 40 are connected in
series with one another in a rephasing configuration such that all of the
actuators are
identical in size and configuration relative to one another. Among the
actuators 40,
two of the actuators comprise first actuators 46 at the first side of the
frame which are
oriented to rotate the steerable wheels associated therewith in first
direction about
their respective steering axis when the first actuators are extended. The
first
actuators also rotate the respective wheels in an opposing second direction
when
retracted.
The actuators 40 also include two second actuators 48 located on the
second walking beam at the opposing second side of the frame which are instead
mounted in an orientation to rotate the associated steerable wheels in the
first
direction about their respective axes when the actuators are retracted. The
second
actuators also rotate the respective wheels in the opposing second direction
when
extended.
The controllable hydraulic output of the vehicle includes a supply line 50
for supply hydraulic fluid under pressure therefrom, and a return line 52 for
returning
hydraulic fluid to the towing vehicle. A suitable switching block 54 including
check
valves serves to connect the supply line 50 to a first input 56 for operation
in one
direction in a first position of the switching block and to connect the supply
line 50 to a
second input 58 for steering the wheels in the opposing direction in a second
position
of the switching block. In each position, the other input 56 or 58 which is
not
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connected to the supply line functions as a return connected to the return
line 52.
As shown in the illustrated embodiment of Figure 4, the first input 56 is
connected to the retraction port of one of the first actuators at the first
side of the
frame. The extension port of that first actuator is in turn connected to the
corresponding extension port of a respective one of the second actuators at
the
second side of the frame. The retraction port of that second actuator is in
turn
coupled to the retraction port of the other first actuator while the extension
port of said
other first actuator is connected to the extension port of the other second
actuator. By
connecting the retraction port of said other second actuator back to the
second input
58 all of the actuators are effectively hydraulically connected in series with
one
another in a rephasing configuration and at least one port of each actuator
acts as a
rephasing port in connection with another one of the actuators.
As shown in Figure 4, actuation of the steering of the wheels in a first
direction is shown by supplying hydraulic fluid to the first input 56 and
connecting the
second input 58 to the return. As shown by the arrows indicating the flow of
hydraulic
fluid, both of the first actuators are retracted while both of the second
actuators are
extended so that all of the steerable wheels are pivoted in a common direction
of
rotation. Alternatively, connecting the hydraulic supply to the second input
58 would
cause retraction of both of the second actuators which would in turn extend
both of
the first actuators to again rotate all of the steerable wheels together, but
in the
opposing direction.
The re-phasing configuration is accomplished by mounting the first and
second actuators in alternating configuration relative to one another and by
supporting
each actuator on a laterally opposed side of the beam from the associated
steerable
wheel. More particularly each actuator is mounted at a cylinder and to be
fixed in
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position relative to the frame while being mounted at the piston end to the
second
portion of the steering arm of the respective wheel at a location
diametrically opposite
from the wheel such that the wheel is steered together with movement of the
piston
end relative to the cylinder end of the actuator.
In further arrangements, the actuators may comprise electrically driven
actuators or other forms of hydraulic actuators such as rotary motors and the
like.
Also, the hydraulic cylinders may be connected in series such that the
retraction port
of each cylinder connects to the extension port of an adjacent cylinder by
appropriately changing the size and configuration from one actuator to the
next in the
series to maintain an equal amount of linear displacement among the series of
actuators. Furthermore, some of the wheels may be interconnected by mechanical
linkages so that fewer individual actuators are required. Individual actuators
associated with respective wheels are preferred however so as not to interfere
with
the walking beam suspension.
In some embodiments, the two wheels of each walking beam can be
steered together using a single actuator by connecting the actuator to a
control arm
pivotally mounted on the beam such that separate link arms connect the control
arm
to the steering arms of the two wheels respectively. The use of a central
control arm
is suited for use with wheels on laterally opposed sides of the beam.
Alternatively, by
mounting the pair of wheels on the same side of the walking beam, a single
link arm
may be connected between the steering arms of the two wheels so that a single
actuator controls movement of the single link arm to pivot the steering arms
and
wheels together.
In use, the conveyor is towed by the towing vehicle by connection of the
hitch connector at the inlet end of the housing to the hitch of the towing
vehicle. The
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path of the vehicle is steered in the usual manner by steering the vehicle
wheels
relative to the frame of the vehicle. The path of the conveyor relative to the
towing
vehicle can be selected to be the same, narrower or wider than the path of the
towing
vehicle using a controller on the towing vehicle which controls the actuators
of the
5 steering mechanism to commonly pivot all of the steerable wheels together in
a
common lateral direction offset from the longitudinal direction.
When rolling generally in the forward direction or an opposing rearward
direction with the towing vehicle, steering the wheels of the conveyor
relative to the
frame of the conveyor effectively controls steering of the conveyor frame
relative to
10 the vehicle about the vertical steering axis of the hitch connection.
Because all of the
wheels are steered together in a common direction, the path of the conveyor
can be
accurately controlled by the towing vehicle independently of the steering of
the towing
vehicle.
Typically if the vehicle wheels are steered to be angularly offset from the
15 forward or rearward direction in a first lateral direction, all of the
wheels of the
conveyor are steered to be angularly offset from the longitudinal direction of
the
conveyor in an opposing second lateral direction opposite to the first lateral
direction
to enable the conveyor to substantially follow the path of the towing vehicle
in the
forward direction or to lead the path of the towing vehicle in the rearward
direction.
Since various modifications can be made in my invention as herein
above described, and many apparently widely different embodiments of same made
within the spirit and scope of the claims without department 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.
