Note: Descriptions are shown in the official language in which they were submitted.
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FIELD SPRAYER AND ENCLOSURE MEMBER THEREFORE
BACKGROUND OF THE INVENTION
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This invention relates to a field sprayer and
particularly to an enclosure member which can effect-
very surround the nozzles of the field sprayer to imp
prove the spraying action.
Field sprayers are an important item of agree-
cultural equipment for spraying fertilizer and herb-
aide in liquid form onto the fields or onto a standing
crop early in its development. Such sprayers gene-
rally comprise a central trailer portion supporting a
tank of the fluid and a pair of booms which extend out-
warmly to each side of the central trailer with a total
boom width of generally 60 to 100 feet. It is also
known to mount the boom on a sprayer coupe which is
self-propelled.
Generally, the boom comprises a framework in
the form of a tubular frame which extends outwardly
and is supported at one or two positions by ground
wheels which control the height of the boom relative to
the ground. On the framework is carried a supply pipe
which supplies spaced nozzles along the length of the
pipe for spraying a curtain of the fluid over the ground
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as the boom moves forwardly.
Alp sprayers of this type have generally been,
until recently, open to the elements and particularly
wind. Recent proposals have been made to provide a flex-
isle cover which can wrap around the framework of the
boom and thus enclose the spraying area to reduce the
effect of the wind on the spraying action.
The main advantages of such covers have gene-
rally been thought to consist in the ability to spray
in windy conditions. However, a market has developed
for a retrofit arrangement of flexible covers which
can be applied to existing sprayer booms of the above
type.
Proposals have also been made for specialty
type spraying devices of a relatively narrow width which
include a cover which extends generally to the ground
to fully enclose a spraying area.
However, the attempts to cover such spraying
arrangements have been fairly rudimentary and have not
been as successful in containing drift as might other-
wise have been expected.
SUMMARY OF THE INVENTION
It is one object of the invention therefore
to provide an improved enclosure arrangement for field
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sprayers which enables spraying efficiency to be improved
According to a first aspect of the invention
therefore, there is provided an enclosure for a field
sprayer of the type having a plurality of nozzles spaced
longitudinally of the sprayer for directing onto the
ground over an area beneath the nozzles and mounted
on ground wheels for moving forwardly over the ground
in a direction transverse to its length, the enclosure
comprising an elongate cover member for extending over
the nozzles from a position forwardly thereof and
adjacent the ground to a position rearwardly thereof
and adjacent the ground so as to include said area to
be sprayed said cover member having an upper wall formed
from a front portion extending upwardly and rearwardly
to a highest point of the upper wall and a rear portion
extending downwardly and rearwardly from the highest
point, and an air guide surface arrangement adjacent
the cover member at the highest point, said upper wall
and air guide surface being shaped and arranged such
that air passing upwardly along said front portion toward
said highest point is redirected downwardly to pass
along said rear portion toward the ground.
According to a second aspect of the invention
there is provided an enclosure for a field sprayer of
the type having a plurality of nozzles spaced longitude-
natty of the sprayer for directing onto the ground over
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an area beneath the nozzles and mounted on ground wheels
for moving forwardly over the ground in a direction
transverse to its length, the enclosure comprising an
elongate cover member for extending over an area to
be sprayed having an upper wall and a flexible front
wall depending downwardly from a front edge of the upper
wall, the flexible front wall being formed from a
flexible sheet having a plurality of vertical slits
spaced longitudinally of the sheet, with each slit
10 extending from a bottom edge to a position adjacent
the top edge so as to divide the sheet into a plurality
of sheet portions, said slits being spaced by a distance
such that each portion can flex over a plant while other
portions remain unflexed.
According to a third aspect of the invention,
there is provided a field sprayer comprising a central
support frame having ground wheels for supporting the
frame, a pair of booms each being movable from a working
position in which the booms extend outwardly from the
frame to a respective side thereof to a transport position
in which the booms trail rearwardly of the central frame,
a plurality of spray nozzles mounted on each boom and
spaced longitudinally of the boom to provide a curtain
of spray across the full width of the sprayer, each
boom being supported on ground wheels spaced outwardly
of the central frame to guide the boom relative to the
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ground, a central pivot member carried by said central
frame and providing a single vertical pivot axis and
each boom including a respective strut means arranged
to extend outwardly to one side of the respective booms
so as to interconnect the boom to the central pivot
member for pivotal movement about said single vertical
axis from said working position in which said strut
means retains the boom in a position forwardly of the
single vertical axis to said transport position in which
said strut means retains the booms in a position spaced
outwardly of the single vertical axis
The enclosure for the field sprayer and the
enclosed field sprayer have a number of important advent-
ages. Firstly, attention has been given to the air flow
in and around the sprayer so that air moving over the
top of the enclosure is constrained to flow in a non-
turbulent manner up one side of the enclosure, down
the other side and rejoin air moving across the ground.
This avoids turbulence immediately behind the enclosure
which can act to lift droplets remaining in the air
stream behind the enclosure and thus cause dispersal
of small droplets of spray away from the crop or ground.
Secondly, within the enclosure, the direction
of spray is arranged along the front of the cover to
aim at the ground or the top of the plants at a position
adjacent the front of the enclosure and immediately
behind the rearwardly flexed position of the front
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downwardly depending flexible wall. This arrangement
positions the spray at the desired position relative to
the plants as they are bent forwardly by the front wall
and also provided the best air flow within the enclo-
sure. These arrangements, properly controlling the
air flows in and around the enclosure, can allow the
use of nozzles which provide very small drops of the
chemical spray. Very small drops have a better spray-
in effect if they reach the desired position but are
much more dependent upon air flow and thus can be lift-
Ed away from the desired position should turbulent flow
cause any wind movements which move away from the plants
either within the enclosure or more importantly, mime-
doughtily behind the enclosure.
A further important improvement relates to
the fact that, as opposed to the conventional arrange-
mint where the enclosure is provided by a flexible
fabric which is draped over the supporting frame and
spray nozzles of the boom, the enclosure is designed
as an integral part of the boom.
In this regard, it is manufactured from stiff
or rigid sheet metal cover plates which effectively pro-
vise the total support for the nozzles and the supply
pipe. Thus, instead of lifting away the flexible covers
S 37
to expose the nozzles for service, the covers are rigid-
lye mounted and the nozzles can be positioned on the out-
or surface of the enclosure at a position which allows
the supply pipe and nozzles to be exposed and arranged
such that the nozzles can be turned away from the enclo-
sure for service.
With the foregoing in view, and other ad van-
taxes as will become apparent to those skilled in the
art to which this invention relates as this specific
lion proceeds, the invention is herein described by
reference to the accompanying drawings forming a part
hereof, which includes a description of the best mode
known to the applicant and of the preferred typical
embodiment of the principles of the present invention,
in which:
DESCRIPTION OF THE DRAWING_
Figure 1 is a plan view of a field sprayer
according to the invention showing the sprayer in work-
in position.
Figure 2 is a plan view of the sprayer of
Figure 1 showing the arrangement in transport position
with the booms trailing rearwardly of the central trail-
or section.
Figure 3 is a cross sectional view along the
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lines 3-3 of Figure 1 on a larger scale showing the
details of the enclosure and nozzle arrangement.
Figure 4 is an isometric view of the enclo-
sure looking from the section of Figure 3 and from a
position to the rear side of the boom.
Figure 5 is a schematic view similar to that
of Figure 3 showing the air spray and crop movements in
use.
In the drawings like characters of reference
indicate corresponding parts in the different figures.
DETAILED DESCRIPTION
The field sprayer comprises a central trailer
section 10 including ground wheels 11 and a supply tank
12 which is of known construction. The trailer 10 in-
eludes a hitch 13 for attachment to a tractor 14 by
which it can be towed across an area to be sprayed in
a working position or in a transport position described
hereinafter.
A pair of booms 15 extend from a position
rearward of the trailer out to respective sides of the
trailer to produce a working width of boom transverse
to the trailer from which fluid can be sprayed to the
ground. As in conventional arrangements, the booms
can be manufactured of various lengths to provide a
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total working width of the order of 10 to 100 feet, de-
pending upon requirements.
As shown, each ox the booms is supported at
its end by a ground wheel arrangement 16 and also by a
wheel
similar ground/arrangement also indicated at 16 at a
position mid-way along the length of the boom.
The ground wheel arrangement 16 is shown also
in Figure 3 and is itself of known construction come
prosing a pair of castor wheels 17, 18 mounted upon a
support beam 19 which extends forwardly of the boom so
that in the working position shown in Figure 1, the
wheels lie parallel to the support beam 19.
The inner end of each of the booms 15 is sup-
ported upon a rearwardly extending arm 20 9 the rear
ward end of which is supported upon a ground wheel 21
which is costarred similar to the wheels 17. Each boom
15 is supported upon the support arm 20 by a connect
tying bracket 22 which extends from the rear corner of
the boom to a pivot mounting 23 to which both of the
brackets 22 are coupled.
The booms 15 are maintained in the working
position, that is transverse to the direction of motion
of the trailer 10, by a pair of radius arms 24 which
extend from the inner support beam 19 of the ground wheel
2537~
arrangement 16 to a position on the hitch 13. The coup-
lying to the hitch 13 is releasable by a conventional
arrangement so that, when released, the booms 15 are
free to pivot about the pivot coupling 23 to take up
the position illustrated in Figure 2 which is the trays-
port position. In this position, the radius rods 24
are stored by latching onto the side of the respective
boom and thus the only interconnection between the
booms 15 and the trailer 10 is provided by the pivot -
coupling 23 and the brackets 22.
It will be appreciated that in the transport
position the wheels 17 and 18 castor to a direction at
right angles to the support bars 19 so as to transport
the booms in the direction of transport. The length of
the brackets 22 is arranged to be sufficient so that
as the booms directly follow the trailer, the inner
wheels 17 of the wheel arrangements 16 are spaced surf-
ficiently to avoid damaging contact. In view of the
fact that the booms fold about the pivot coupling 23,
which is a single coupling, they also turn about this
coupling during turning movements in transport and this
prevents relative movement between each side of the
boom during such turning movements.
Thus, the booms 15 can follow the trailer and
SLY
particularly the pivot coupling 23 and without any other
interconnection can avoid, running into each other during
such movement.
Reverting to Figure 1, it will be noted that
each boom includes a pair of elongate enclosures gene-
rally indicated at 25 which extend from the inner end
adjacent the trailer to the outer end of the boom, the
construction of which will be described hereinafter. In
addition an airfoil 26 is mounted on top of the enclo-
sure 25 again in a position described hereinafter. The airfoil and enclosures extend from the inner end to the
inner ground wheel arrangement 16 at which there is pro-
voided a hinge coupling indicated at 27. From that point,
they extend to the outer end of the boom and thus effect
lively along the full length of the enclosure 25.
Along the front edge of the cover is provided
a feed tube 28 which again extends along the full length
of the boom from a supply line 29 connected to the tank
12. The tube 28 is formed in two sections again split
at the inner wheel arrangement 16 and coupled by a flex-
isle section 30. The single feed tube 28 supplies the
nozzles which are arranged at spaced relation along the
length of the tube 28 by branch tubes 281 arranged at
right angles to the length of the boom.
37
Turning now to the structural details of the
booms as shown in very much enlarged views in Figures 3
and 4, they are of constant cross section as illustra-
section
ted. Specifically, each boom/comprises an enclosure
formed by an upper wall 31 which has a front section
32 and a rear section 33, both of which are inclined
from front and rear edges respectively to a top surface
34 which is horizontal and narrow relative to the width
of the upper wall 31. The angle of inclination is of
the order of 45. At the lowermost edge each of the
sections 32, 33 is turned downwardly lo form a vertical
flange 35, 36 for attachment to front and rear walls
respectively.
The upper wall 31 is formed from rigid sheet
metal material which can be bent into shape as shown
and formed either from a single piece or effectively
the front and rear sections 32, 33 can be formed from
separate pieces interconnected by an overlying layer
forming the top section 34. The width of the enclo-
sure is, in one example, of the order of 30 inches.
The upper wall 31 is effectively self-support-
in but can be stiffened longitudinally by longitudinal
channel clamps 37, 38. The open base of the channels
37, 38 is clamped to the flange 35, 36 by a plurality
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of bolts 39 spaced longitudinally of the flanges. These
channels 37, 38 provide stiffening of the flanges 35,
36 to give lateral stiffness to the upper wall, that is
to increase its resistance to bending movement about a
vertical axis passing through one of the flanges 35,
36.
A front wall 40 is formed in two layers from
a flexible plastic material such as polyethylene or
other fabric which is resistant to chemicals and also
has a good wear resistance in view of its contact with
the ground or with plants. The wall thus comprises a
front layer 41 and a rear layer 42 which are in contact
and lie directly parallel and co-extensive, clamped to-
getter by the flange 35 and the channel 37.
Each of the layers 41, 42 has a plurality of
equally spaced vertical slits or cuts formed in the full
height of the layer, the slits in the front layer in
Figure 4 being illustrated in dashed line. It will be
noted that the slits 43 in the front layer 41 are off-
set relative to the slits 44 in the rear layer by a disk
lance less than the spacing between the slits.
The wall thus formed has slits which are surf-
ficiently frequent to allow it to flex over plants and
obstacles while being sufficiently stiff to bend crop to
74
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induce movement in the crop that ensures complete cover-
age of each plant with chemical without injuring the
plant. At the same time the staggered slits allow the
required flexibility while preventing the sprayed comma-
eel from escaping between the two layers. Thus, in order
to escape each drop needs to make a 90 turn to pass
from inside the inner layer between the layers and then
out of the front layer. Any fluid which does happen to
escape, escapes by seepage rather than movement within
an airflow and therefore can run down the front face of
the layer 41 and be wiped over the crop contacting the
front face as shown in Figure 5.
The downwardly depending rear wall indicated
at I comprises a single layer of the flexible fabric
including slots 46 similar to those of the front wall.
The height of the front and rear walls is the same and
can be of the order of eight inches which is suffice-
en to provide the required flexibility at the crop
height at which spraying normally takes place.
The airfoil 26 extends over the upper apex of
the upper wall 31 and is symmetrical relative thereto,
that is, a first section thereof lies parallel to the
front section 32, the rear section thereof lies parallel
to the rear portion 33 and an upper section thereof en
37
tends over the wall 34. To provide the required air
flow characteristics, the airfoil is preferably curved
through its upper portion either as a smooth curve or
as a number of straight sections bent relative to one
another through the curve. The spacing between the
undersurface of the airfoil and the upper surface of
the wall 31 is preferably of the order of three inches,
but it can lie in the range two inches to six inches.
In addition, the spacing between the rear
edge of the airfoil and the adjacent rear cover panel
can be reduced relative to the spacing between the front
edge and the front cover panel to increase the velocity
of air as it passes under the airfoil.
The airfoil is mounted relative to the upper
wall 31 by a number of spars 46. Each of these come
proses a plate with right angled flanges along each
side, the flanges shown in Figure 4 at 47 and 48 rest
pectively, the former being attached to the undresser-
face of the airfoil 26 and the latter being attached
to the outer surface of the upper wall section 32 or
33.
Thus, as shown in Figure 3, two such spars 46
are positioned on either side of the airfoil supporting
the front and rear sections of it relative to the upper
_ 16
wall. The two spars are tied together at the top end
by a plate 461. As shown in Figure 1, there are a numb
bier of such spars 46 positioned in spaced relation along
the length of the airfoil.
Not only do the spars 46 support the airfoil,
they also, in combination with the airfoil and tying
plate 461, provide vertical stiffness to the upper wall
so as to prevent the cover flattening by spreading of
the front and rear edges of the cover and so as to prey
vent bending movement about a horizontal axis passing
through the wall 34. The upper wall 31 is therefore
laterally and vertically stiffened by the channels and
by the spars and airfoil, but is flexible in rotation
about an axis along its length, allowing it to follow
the ground while traveling over uneven terrain, for
example formed by koalas.
The boom sections are therefore effectively
formed by the enclosure or cover member and particular-
lye the upper wall thereof, and this provides effective-
lye the whole strength of each of the booms without the necessity for further framework.
Each section of the pipe 28 is supported on
the front cover 26 at a position adjacent the front
edge thereof at a position in front of the spars 46.
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Each section 28 carries a plurality of rearwardly ox-
tending branch pipes 281 each leading to a respective
nozzle, one of which is generally indicated in Figures
3 and 4 at 51, the nozzles being of conventional con-
struction and attached to the pipe section 281 so as
to extend therefrom to a jet 52 from which the fluid
in the pipe 28 is ejected in a fan.
The pipe 28 is first positioned such that it
interferes as little as possible with the air from
over the cover while being accessible on the outer sun-
face rather than hidden within the cover. The branch
pipes 281 extend directly rearwardly and hence inter-
lore very little with air moving rearwardly over the
cover.
The nozzle in a working position projects
through the airfoil with the jet 52 projecting into
an opening 53 in the rear wall section 33. The open-
in 53 is at the bottom of an indentation 54 so that
there is no possibility of the fluid exiting from the
jet being influenced by air streams passing over the
surface 33 or of the fluid failing to enter within the
opening 53 into the interior of the enclosure defined
by the upper wall 31.
The indentation 54 is elongate so as to
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allow the nozzle 51 to be removed from the bracket in-
to a position in which it is exposed from the outer
surface of the airfoil 26 as shown in phantom in Figure
3. To allow this movement there is provided a slot
55 in the airfoil 26 at the position of the nozzle.
The nozzle can thus be exposed for cleaning merely by
removing the nozzle without the removal of any covers
or the movement of any covers. The nozzle can, of
course, be changed for a different type of nozzle de-
pending upon the spray requirements at the time of use but the structure of the nozzles is of conventional
arrangement and therefore will not be described in de-
tail here.
As shown in Figure 5, the direction of the jet
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52 is arranged such that the fan provided whereby lies
in a plane projecting generally along the front wall
section 32, that is within the forward area of the en-
closure from the top part of the rear wall section 33.
The actual direction of the plane indicated
at 55 is such that it lies immediately behind the end
of the front wall 40 in its flexed position caused by
the forward movement of the implement and the contact
of the front wall 40 with the plants or with the ground
on which spraying is taking place. This flexed position
is shown in Figure 5 where the wall 40 flexes rearwardly
while at the same time depressing slightly the plants
standing from the ground. The spray along the axis 55
thus contacts the plants while they are bent forwardly
so that it can enter between the plants and ensure that
they are fully coated.
The awry lines are shown schematically in
Figure 5 where it will be noted that air engaging the
front part of the upper wall moves upwardly along the
upper wall and then is turned over the apex at the top
of the upper wall to run down the rear section 33. This
produces smooth flow of the air which can then return to
its normal field pattern rearwardly of the spray enclo-
sure. At the same time air contacting the front wall
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40 or below the front wall 40 tends to run under the
enclosure and to swirl around within the enclosure en-
gaping again in a smooth manner along the ground to
join with the air passing over the top of the enclo-
sure. In this way, turbulence is avoided maintaining
the smooth flow of air over the ground and avoiding
air movement in an upward direction behind the enclo-
sure which can act to lift spray away from the intent
dyed area.
Within the enclosure, the forward direction
of the jet along the plane 55 creates a swirl of the
air or assists in that swirl within the enclosure
which improves the coverage efficiency of the spray.
The arrangement shown allows the use of no-
ales providing very small droplets of the fluid where-
by application rates as low as one gallon per acre up
to forty gallons per acre can be achieved with 50 to
400 micron drops.
The enclosure forming the booms therefore
improves spraying efficiency not only in conditions
of high wind where spraying would not otherwise be pus
sidle but also under normal spraying conditions where
movement of the air is caused by forward movement of
the implement over the ground. For these reasons,
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the enclosure is a permanent structure forming the
framework for the boom and cannot be removed.
The upright 49 adjacent the hinge 27 (Figure
3) attached to the wheel assembly is attached rigidly
to the channel 39 of the inner section of each boom.
The inner end of the outer section is coupled to the
upright by pivot bolts which allow the outer section
to pivot relative to the inner section about a horizon-
tat axis. It will be appreciated that if a third sea-
lion is added, it also is pivoted in a similar manner
to the outer end of the second section.
The ground wheels of the second or outermost
section are arranged directly at the end of the section
and thus properly support the end without any overhang
or cantilever section. Thus, the end its properly con-
trolled in its height relative to the ground and fur-
therm ore, the outermost ground wheels can be used as a
ground marker for the end of the boom and as a follower
on the next path of the boom over the field.
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
so
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contained in the accompanying specification shall be
interpreted as illustrative only and not in a limit-
in sense,
