U.S. patent application number 10/160261 was filed with the patent office on 2002-10-17 for method and apparatus for harvesting crops.
Invention is credited to McLeod, Robert H., Oswald, Wilfried.
Application Number | 20020151336 10/160261 |
Document ID | / |
Family ID | 4163624 |
Filed Date | 2002-10-17 |
United States Patent
Application |
20020151336 |
Kind Code |
A1 |
McLeod, Robert H. ; et
al. |
October 17, 2002 |
Method and apparatus for harvesting crops
Abstract
A method and system of harvesting crops involves cutting and
threshing the crop, separating graff (a mixture of grain kernels,
chaff, weed seeds, and other organic matter) from straw (plant
stalks), and returning the straw to the field. This is preferably
carried out in a harvesting unit of the pull type having a graff
storage tank. The collected graff is moved to a stationary cleaning
mill in a different location by means of a suitable vehicle such as
a truck. Storage of the graff prior to cleaning is avoided and the
cleaning mill, and preferably the harvesting unit and vehicle, are
designed to make this possible. This avoids difficulties caused by
the poor material flow of graff. Various details of the equipment
are also novel.
Inventors: |
McLeod, Robert H.;
(Winnipeg, CA) ; Oswald, Wilfried; (Lorette,
CA) |
Correspondence
Address: |
KIRBY EADES GALE BAKER
BOX 3432, STATION D
OTTAWA
ON
K1P 6N9
CA
|
Family ID: |
4163624 |
Appl. No.: |
10/160261 |
Filed: |
June 4, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10160261 |
Jun 4, 2002 |
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09590362 |
Jun 9, 2000 |
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6422937 |
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Current U.S.
Class: |
460/12 |
Current CPC
Class: |
A01D 41/04 20130101;
B07B 9/00 20130101; A01F 7/00 20130101; B07B 4/08 20130101; B07B
13/08 20130101; B07B 4/02 20130101; B07B 2201/04 20130101; B07B
7/08 20130101; A01D 91/00 20130101; B07B 13/04 20130101; B08B 3/06
20130101; A01D 41/1208 20130101 |
Class at
Publication: |
460/12 |
International
Class: |
A01F 012/52 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 9, 1999 |
CA |
2,274,288 |
Claims
What I claim is:
1. A method of harvesting and cleaning a plant crop, wherein the
crop is cut from a field area and threshed in a mobile harvesting
unit to produce stalks that are returned to the field area and
"graff", a mixture including grain, chaff and weed seeds, which is
collected within the harvesting unit; the collected graff is
transferred periodically from the harvesting unit to at least one
vehicle and transported by said at least one vehicle to a cleaning
mill, and the graff is cleaned by the cleaning mill to produce a
cleaned grain product and "millings", a mixture including chaff and
weed seeds; wherein the method is operated to avoid storage of the
graff prior to cleaning by said cleaning mill.
2. The method of claim 1, wherein storage of the graff prior to
cleaning is avoided, at least in part, by emptying an entire graff
load from said at least one vehicle by direct dumping of the entire
graff load into a graff receiving unit of said cleaning mill, and
directly feeding graff from the dumped load into a graff entrance
of the cleaning mill at a rate at which the graff can be
continuously cleaned by the cleaning mill, until all of said load
has been fed into the cleaning unit.
3. The method of claim 2, wherein graff is fed from the dumped load
to the graff entrance of the cleaning mill by removing graff from a
lowermost layer of the dumped load over substantially the entire
transverse width of said dumped load to avoid interruptions of
graff feed caused by binding, blocking, or bridging of the graff
within the load.
4. The method of claim 3, wherein the graff is removed from said
lowermost layer of the dumped load by positioning the load on a
surface and moving the surface, or elements extending across the
surface, beneath the load.
5. The method of claim 4, wherein the surface is inclined upwardly
towards the graff entrance of the cleaning mill, and the load is
kept in contact with the inclined surface by raising a floor of the
graff receiving unit to form a downwardly inclined chute that urges
the load against the upwardly inclined surface.
6. The method of claim 1, wherein storage of the graff prior to
cleaning is avoided, at least in part, by making the graff holding
capacity of the harvesting unit the same as or smaller than the
graff holding capacity of said at least one vehicle, so that all of
said graff collected in said harvesting unit may be transferred in
a single emptying operation to said at least one vehicle.
7. The method of claim 6, wherein the capacity of the harvesting
unit is made substantially the same as the capacity of the at least
one vehicle.
8. The method of claim 1, wherein storage of said graff prior to
cleaning is avoided, at least in part, by cleaning the graff in the
cleaning mill at a rate that is the same as or higher than the rate
of graff output from the field area.
9. The method of claim 8, wherein the rate of cleaning of the graff
by the cleaning mill is substantially the same as the rate of graff
output from the field area.
10. The method of claim 1, wherein storage of said graff prior to
cleaning is avoided, at least in part, by operating said at least
one vehicle such that graff is conveyed from the harvesting unit to
the cleaning mill at a rate high enough to avoid substantial
waiting periods between emptying operations of said harvester
unit.
11. The method of claim 1, wherein the graff is transported from
the harvesting unit to the cleaning mill in a single vehicle
travelling continually back and forth between the harvesting unit
and the cleaning mill.
12. A system for harvesting and cleaning a plant crop, which
includes a harvesting unit for cutting a crop from a field area and
threshing the cut crop to produce stalks that are returned to the
field area and "graff", a mixture including grain, chaff and weed
seeds, which is collected within the harvesting unit; at least one
vehicle for receiving collected graff from the harvester unit when
the harvesting unit is at least partially full, and for
transporting the graff to a cleaning mill; and a cleaning mill
located in a yard area remote from the field area, for cleaning the
graff to produce a cleaned grain product and "millings", a mixture
containing chaff and weed seeds; wherein the system excludes any
device for storage of the graff prior to cleaning of the graff in
the cleaning mill.
13. The system of claim 12, wherein the cleaning mill includes a
graff receiving unit into which said at least one vehicle may empty
an entire graff load by dumping, the receiving unit including
feeding apparatus for directly feeding graff from the dumped load
into a graff entrance of the cleaning mill.
14. The system of claim 13, wherein the feeding apparatus removes
graff from a lowermost layer of the dumped graff load over
substantially the entire transverse width of the dumped load,
thereby avoiding interruptions caused by binding, blocking or
bridging of the graff within the load.
15. The system of claim 14, wherein the feeding apparatus includes
a surface on which the load may be positioned, and means for moving
the surface, or elements extending transversely across the surface,
to convey graff from the load to the graff entrance of the cleaning
mill.
16. The system of claim 15, wherein the surface is inclined
upwardly to the graff entrance of the cleaning mill, and the
receiving unit includes a floor that may be raised to form a
downwardly inclined chute that keeps the load in contact with the
inclined surface.
17. The system of claim 15, wherein the elements extending
transversely across the surface are mutually spaced transverse
slats supported and moved towards the graff entrance of the
cleaning mill by rotating endless chains passing around the
inclined surface.
18. The system of claim 6, wherein a rotating transverse roller is
provided above the inclined surface at an upper end thereof to
ensure that graff fed to the graff entrance of the cleaning mill is
in the form of a layer of uniform thickness.
19. The system of claim 12, wherein the harvesting unit has a graff
holding capacity that is the same as or smaller than the graff
holding capacity of said at least one vehicle used for graff
transportation.
20. The system of claim 12, wherein the cleaning mill operates at a
rate of cleaning of the graff that is the same as or higher than
the rate of graff output from the field area.
21. The system of claim 12, wherein said at least one vehicle may
be operated at a rate high enough to convey graff from the
harvesting unit to the cleaning mill while avoiding substantial
waiting periods between emptying operations of said harvesting
unit.
22. The system of claim 21, wherein a single vehicle is provided
for conveying graff between the harvesting unit and the cleaning
mill.
23. A stationary cleaning mill for "graff", a mixture including
grain, chaff and weed seeds, comprising an entrance for the graff,
screening apparatus for separating grain from the graff to produce
cleaned grain and "millings", a mixture including chaff and weed
seeds, and separate outlets for the cleaned grain and millings;
wherein the cleaning mill includes a receiving unit for the graff
for feeding the graff to the entrance of the graff cleaning mill,
said receiving unit being sized to permit a graff delivery vehicle
to drive in to the receiving unit to transfer an entire vehicle
load of graff to the receiving unit by a direct dumping operation
of the entire vehicle load.
24. The cleaning mill of claim 23, wherein the receiving unit
includes a receptacle for the graff load and a feed device for
raising graff from the receptacle to the entrance of the mill.
25. The cleaning mill of claim 23, wherein the mill includes a fan
for blowing a stream of air through the graff to remove at least
chaff, but not grain, a centrifugal separator for removing the
chaff from the stream of air, and ductwork for recirculating air
from the centrifugal separator to the fan.
26. The cleaning mill of claim 25, wherein the mill includes an
aspirator for receiving a falling curtain of graff, and ductwork
for directing said stream of air through the falling curtain of
graff in the aspirator, thereby allowing a mixture of grain and
weed seeds to fall to a lower part of the aspirator while removing
chaff via said stream of air.
27. The cleaning mill of claim 26, wherein the screening apparatus
includes a frame containing a series of screens, arranged one above
another, of different mesh sizes suitable for separating grain from
weed seeds, a delivery apparatus for delivering a mixture of grain
and weed seeds from the lower part of the aspirator to an upper
part of the frame, an outlet for cleaned grain emerging from the
series of screens and an outlet for weed seeds emerging from the
series of screens.
28. The cleaning mill of claim 27, wherein the mill includes a
milling device for crushing the weed seeds, and a delivery device
for combining crushed weeds seeds with chaff removed from the
graff.
29. The cleaning mill of claim 27, wherein the screening apparatus
includes a plenum through which screened grain falls before being
discharged from the mill, the plenum including ducting for
directing a flow of air through the falling screened grain to
remove dust, and ducting for introducing the dust into the
centrifugal separator.
30. The cleaning mill of claim 26, wherein said screening apparatus
is positioned between said graff entrance and said centrifugal
separator, and said mill includes ductwork that directs said stream
of air through said screening apparatus as graff from said entrance
is passed through the screening apparatus.
31. The cleaning mill of claim 30, wherein said screening apparatus
has an outlet for screened graff components other than cleaned
grain, and said outlet feeds said screened graff components other
than cleaned grain into said centrifugal separator.
32. The cleaning mill of claim 31, wherein a cleaned grain outlet
is provided at a lower part of said screening apparatus to remove
cleaned grain from the cleaning mill.
33. The cleaning mill of claim 30, wherein a material-conveying fan
is provided at an outlet for said millings, said fan impacting said
millings to cause at least partial crushing or breaking of weed
seeds in the millings, removing said millings from the cleaning
mill, and propelling said millings through said outlet for the
millings.
34. A stationary cleaning mill for "graff", a mixture including
grain, chaff and weed seeds, comprising an entrance for the graff,
screening apparatus for separating grain from the graff to produce
cleaned grain and "millings", a mixture including chaff and weed
seeds, and separate outlets for the cleaned grain and millings;
wherein the cleaning mill includes a material-conveying fan at the
outlet for the millings, said material-conveying fan impacting said
millings to cause at least partial crushing or breaking of weed
seeds in the millings, removing said millings from the cleaning
mill, and propelling said millings through said outlet for the
millings.
35. The cleaning mill of claim 34, wherein said material-conveying
fan is the only apparatus provided in the cleaning mill for
impacting said weed seeds.
36. The cleaning mill of claim 23, wherein ductwork is provided at
said outlet for the millings for conveying said millings to a
location at a distance from said cleaning mill, said ductwork
having a centrifugal separator at an outer end thereof to slow
discharge of millings from the outer end of the ductwork.
37. A mobile harvesting unit for harvesting "graff", a mixture
including grain, chaff and weed seeds, including a wheeled
harvester body and a harvesting header at the front of the
harvester body for cutting a crop from a field area, the harvester
body containing a threshing unit for the cut crop for separating
stalks from graff, a discharge for discharging separated stalks
back to the field area, and a storage tank for storage of the
separated graff, wherein the storage tank has a well at a rear of
the tank, and the tank has a floor provided with a movable surface,
or elements that move over said floor, to convey graff rearwardly
in the tank to said well.
38. The harvester unit of claim 37, wherein a collection bed for
graff is provided beneath the threshing unit, and the collection
bed includes a transverse graff collection trough at a rear end
thereof, and a plurality of rotatable augers for moving graff
rearwardly towards the trough.
39. The harvester unit of claim 38, wherein the transverse graff
collection trough houses a pair of co-axial augers for transferring
graff to opposite lateral ends of the graff collection trough, and
a pair of graff elevators is provided, one at each lateral side of
the storage tank, for lifting graff from the opposite lateral ends
of the graff collection trough and transferring the graff to the
storage tank.
40. The harvester unit of claim 37, wherein the storage tank
includes at least one leveling auger for spreading out graff fed
into the tank from the threshing unit.
41. The harvester unit of claim 37, wherein the storage tank has a
well at a rear of the tank, and the tank contains at least one
auger for conveying graff towards the well.
42. The harvester unit of claim 37, wherein the elements that move
over said floor are mutually spaced lateral slats connected to
endless chains that rotate around said floor of the tank.
43. The harvester unit of claim 37, wherein a discharge device is
provided for emptying the storage tank of graff when the tank is
full, the discharge device having an elongated discharge tube that
is pivotable on the harvesting unit, allowing discharge of graff to
a vehicle positioned at a side or rear of the harvesting unit.
44. The harvester unit of claim 37, wherein a discharge device is
provided for emptying the storage tank of graff when the tank is
full, the discharge device comprising an elongated enclosed chute
extending laterally from the rear of the storage tank, said chute
containing a conveyor for removing graff from the storage tank.
45. The harvester unit of claim 44, wherein the chute is pivotable
about a generally horizontal axis so that an outer end of the chute
may be raised or lowered.
46. The harvester unit of claim 37, wherein the storage tank has
side walls that slope inwardly and downwardly at an angle that
causes graff to move towards a bottom of the tank without
substantial binding or bridging of the graff within the tank.
47. The harvester unit of claim 46, wherein a bottom wall of the
storage tank rises to a central peak from said sidewalls to a
centre of the tank at angles that substantially prevent binding or
bridging of the graff as it moves downwardly in the tank.
48. The harvester unit of claim 37, wherein the interior of the
tank has a low friction surface.
49. The harvester unit of claim 37, wherein the tank has a rear
well, and the unit contains at least one auger to move graff in the
tank towards and into the well.
50. The harvester unit of claim 37, wherein the tank has at least
one agitator for agitating the graff in the tank to facilitate
movement of the graff.
51. The harvester unit of claim 37, wherein the tank has a front
wall that slopes inwardly from top to bottom.
52. A receiving unit for "graff", a mixture containing grain, chaff
and weed seeds, for feeding graff to an entrance of a graff
cleaning mill, including a receptacle for graff and a conveyor for
raising graff from the receptacle to the entrance; wherein the
receptacle is sized to permit a graff delivery vehicle to drive
into the receptacle and to deposit an entire vehicle load of graff
into the receptacle by a direct dumping operation.
53. The receiving unit of claim 52, wherein the receptacle for
graff has a floor that is pivoted adjacent to the conveyor, so that
the floor of the receptacle may be raised to tilt downwardly
towards the conveyor.
54. The receiving unit of claim 52, wherein the conveyor has an
upwardly ramped floor provided with a moving surface that conveys
graff from the receptacle to the entrance.
55. The receiving unit of claim 52, wherein the moving surface is
provided by a plurality of mutually spaced transverse slats that
are moved across the ramped floor by rotating endless chains
rotating around the ramped floor.
56. The receiving unit of claim 52, wherein a rotating transverse
roller is provided above the moving surface at an upper end thereof
to ensure that graff fed to the entrance of the cleaning mill is in
the form of a layer of graff of uniform thickness.
57. The receiving unit of claim 52, wherein the receptacle and the
conveyor have raised sides to confine the graff within the
receiving unit.
Description
BACKGROUND OF THE INVENTION
[0001] 1. FIELD OF THE INVENTION
[0002] This invention relates to the harvesting of grain and seed
crops of the kind that are conventionally harvested by means of a
combine harvester. More particularly, the invention relates to
systems, methods and apparatus for harvesting such crops.
[0003] 2. DESCRIPTION OF THE PRIOR ART
[0004] The applicant herein has already disclosed a novel method of
and apparatus for harvesting grain and seed crops that provide an
alternative to the use of conventional combine harvesters. In this
regard, reference is made to U.S. Pat. No. 5,794,423 issued on Aug.
18, 1998; U.S. Pat. No. 5,795,222 issued on Aug. 18, 1998; and U.S.
Pat. No. 5,873,226 issued on Feb. 23, 1999; all of these patents
having been assigned to McLeod Harvest Inc. and are referred to
collectively in the following description as "the McLeod
patents."
[0005] A conventional combine harvester operates by carrying out
all of the harvesting steps in the field on a continuous basis. The
crop plants are cut, the cut plants are threshed to separate grain
(or seeds such as peas, etc.), chaff and (inevitably) weed seeds
firm the stalks, the grain is then cleaned by separating it from
the chaff and weed seeds, the grain is delivered to a waiting
collection vehicle, and the stalks, chaff and weed seeds are
returned to the field. The disadvantages of this are that (a)
combine harvesters are very expensive to purchase and to operate;
(b) they are not very efficient at cleaning the grain, so some
grain is lost and/or further grain cleaning is required; and (c)
chaff and weed seeds are returned to the field, so that their
economic value is lost and weeds proliferate.
[0006] The concept underlying the systems disclosed in the above
patents is that, instead of attempting to carry out all of the
harvesting steps in the field, only the step of threshing and
removing stalks is carried out, and the remaining product (a
mixture of grain, chaff and weed seeds--referred to by the coined
word "graff") is collected and transported to a fixed grain
cleaning site. The advantage of this is that the harvesting
equipment may be less complicated and expensive than a conventional
combine harvester, the cleaning of the grain may be carried out
more efficiently at a fixed site, the economic value of the chaff
and weed seeds may be realized, and the need for herbicides is
reduced (because the weed seeds are collected rather than being
returned to the field).
[0007] It has been found that this system is extremely effective,
but inconveniences have been encountered in that graff has proven
to be a difficult material to handle and process. Since graff
contains a large percentage of chaff, it is bulky for its weight
and it is quite fibrous in composition. Unlike grain collected by a
combine harvester, graff does not easily "flow" from containers and
it is difficult to move by conventional means, such as augers,
because it bridges or binds within itself and does not flow
internally to replace material that has been removed from the
bottom of a container or pile of the material. In general, it can
be said that graff tends to pack, clump, bridge, rat-hole and bind,
rather than flow smoothly. This causes problems not only when the
graff is stored in silos or the like before it is processed, but
also causes difficulties of material flow within the harvesting
device and transportation vehicles.
[0008] Moreover, graff is difficult to store because, if stored in
the open, it tends to blow away and also to spoil if it gets wet.
However, if stored in a container, it is difficult to remove for
the reasons mentioned above.
[0009] Additionally, there is a need to improve the overall
efficiency of the system generally and to improve the manner in
which individual components operate in order to increase the
economic competitiveness of the system with conventional harvesting
systems.
SUMMARY OF THE INVENTION
[0010] An object of the invention is to improve the efficiency and
to reduce the equipment cost of carrying out a grain harvesting
method of the type disclosed in the patents mentioned above.
[0011] Another object of the invention, at least in its preferred
forms, is to overcome difficulties caused by the poor flow
properties of graff.
[0012] Another object of the invention, at least in broader
aspects, is to optimize a grain harvesting system as opposed to a
single grain harvesting machine such as a conventional combine
harvester.
[0013] Another object of the invention is to reduce the operational
cost of carrying out a grain harvesting method of the type
disclosed in the patents mentioned above.
[0014] Another object of the invention, at least in its preferred
forms, is to improve the effectiveness of the harvesting unit used
to separate the graff from the crop stalks in the field.
[0015] Another object of the invention, at least in its preferred
forms, is to improve the effectiveness of the grain cleaning mill
used to separate grain from the remainder of the graff at a fixed
site and to process crop the residue.
[0016] According to one aspect of the invention, there is provided
a method of harvesting and cleaning a plant crop, wherein the crop
is cut from a field area and threshed in a mobile harvesting unit
to produce stalks that are returned to the field area and "graff",
a mixture including grain, chaff and weed seeds, which is collected
within the harvesting unit; the collected graff is transferred
periodically from the harvesting unit to at least one vehicle and
transported by said at least one vehicle to a cleaning mill, and
the graff is cleaned by the cleaning mill to produce a cleaned
grain product and "millings", a mixture including chaff and weed
seeds. To avoid problems caused by the poor flow characteristics
and very low density of graff, the method is operated to avoid
storage of the graff prior to cleaning by the cleaning mill.
[0017] What we mean by avoiding storage of the graff prior to
cleaning is that the graff is not transferred to any temporary
storage container or storage pile from the time it is produced by
the harvester to the time it is cleaned by the cleaning mill. The
graff is held only in the harvester unit and the vehicle, and is
fed immediately into the cleaning mill. Consequently, the use of
stationary surge bins and the like at the cleaning mill or other
area is specifically avoided. The graff is fed directly from the
harvesting unit to the vehicle, and directly from the vehicle to
the a receiving unit for the cleaning mill from which it is fed
substantially immediately and completely into the cleaning
mill.
[0018] Thus, according to another aspect of the present invention,
there is provided a system for harvesting and cleaning a plant
crop, which includes a harvesting unit for cutting a crop from a
field area and for threshing the cut crop to produce stalks that
are returned to the field area and "graff", a mixture including
grain, chaff and weed seeds, which is collected within the
harvesting unit; at least one vehicle for receiving collected graff
from the harvester unit when the harvesting unit is at least
partially full, and for transporting the graff to a cleaning mill;
and a cleaning mill located at a site (yard area) remote from the
field area, for cleaning the graff to produce a cleaned grain
product and "millings", a mixture containing chaff and weed seeds.
The system specifically excludes and avoids the use of any device
for storage of the graff prior to cleaning of the graff in the
cleaning mill.
[0019] According to another aspect of the invention, there is
provided a stationary cleaning mill for graff, comprising an
entrance (usually located at an elevated position) for the graff,
screening apparatus for separating grain from the graff to produce
cleaned grain and millings, and separate outlets for the cleaned
grain and millings. The cleaning mill includes a receiving unit for
the graff for feeding the graff to the entrance of the graff
cleaning mill, the receiving unit being sized to permit a graff
delivery vehicle to drive into the receiving unit to transfer an
entire vehicle load of graff to the receiving unit by a direct
dumping operation of the entire vehicle load.
[0020] In another aspect, the invention provides a stationary
cleaning mill for graff, comprising an entrance (usually located an
elevated position) for the graff, screening apparatus for
separating grain from the graff to produce cleaned grain and
millings, and separate outlets for the cleaned grain and millings.
The cleaning mill includes a material-conveying fan at the outlet
for the millings, the material-conveying fan impacting the millings
to cause at least partial crushing or breaking of weed seeds in the
millings, removing the millings from the cleaning mill, and
propelling the millings through the outlet for the millings.
[0021] According to yet another aspect of the invention, there is
provided a mobile harvesting unit for harvesting graff, including a
wheeled harvester body and a harvesting header at the front of the
harvester body for cutting a crop from a field area, the harvester
body containing a threshing unit for the cut crop for separating
stalks from graff, a discharge for discharging separated stalks
back to the field area, and a storage tank for storage of the
separated graff. The harvesting unit includes an elongated hitching
arm having opposite lateral ends for connection at one end to the
harvester body and at an opposite end to a rear portion of a
propulsion device, the hitching arm having a raised section
intermediate the opposite ends passing over and clear of the
harvesting header.
[0022] According to yet another aspect of the invention, there is
provided a hitching arm for a graff harvester, comprising a rigid
elongated element having two opposite ends for connection,
respectively, to the graff harvester and to a propulsion device.
The arm has upwardly extending sections extending from each
opposite end towards a cent-e of the hitching, arm, and an elevated
centre section.
[0023] According to still another aspect of the invention, there is
provided a receiving unit for graff, for feeding graff to an
elevated entrance of a graff cleaning mill, including a receptacle
for graff and a conveyor for raising graff from the receptacle to
the elevated entrance. The receptacle is sized to permit a graff
delivery vehicle to drive into the receptacle and to deposit an
entire vehicle load of graff into the receptacle by a direct
dumping operation.
[0024] Preferably, the invention may provide a method of harvesting
and cleaning a plant crop, wherein the crop is cut from a field
area and threshed in a mobile harvesting unit to produce stalks
that are returned to the field area and graff, a mixture of
threshed grain kernels, chaff and weed seeds, which is collected
within the harvesting unit, the collected graff is transferred to a
vehicle when the harvesting unit is full, the graff is transported
by the vehicle to a cleaning mill located in a yard area remote
from the field area, and the graff is cleaned automatically by the
cleaning mill to produce a cleaned grain product and a mixture of
chaff and weed seeds, wherein a capacity of the harvesting unit to
hold graff is made the same as or smaller than a capacity of a
vehicle used for the delivery, the rate of cleaning of the graff by
the cleaning mill is made the same as or higher than a rate of
graff output from the field area averaged over several cycles of
filling and emptying the harvesting unit and transfer to the
vehicle, and the number and speed of operation of the vehicles is
made high enough to avoid substantial waiting periods between
filling of the harvesting unit with graff and transfer of the
collected graff to the vehicle.
[0025] Preferably, the capacity of the harvesting unit is
substantially the same as the capacity of the vehicle, and a single
vehicle is provided for transporting the graff.
[0026] It is also preferable that the capacity of the cleaning mill
to hold and process graff is no less than the capacity of the
vehicle to transport graff from the field area to the cleaning
mill, and the rate of cleaning of the graff by the cleaning mill is
about the same as the rate of graff output from the field area.
[0027] In another preferred form, the invention provides a system
of harvesting and cleaning a plant crop, which comprises: a
harvesting unit for cutting a crop from a field area and threshing
the cut crop to produce stalks that are returned to the field area
and "graff", a mixture of grain, chaff and weed seeds, which is
collected within the harvesting unit, a vehicle for receiving
collected graff from the harvester unit when the harvesting unit is
full, and for transporting the graff to a cleaning mill; and a
cleaning mill located in a yard area remote from the field area,
for cleaning the graff to produce a cleaned grain product and
"millings", a mixture of chaff and weed seeds, wherein a capacity
of the harvesting unit to hold graff is made the same as or smaller
than a capacity of a vehicle used for the delivery, a rate of
cleaning of the graff by the cleaning mill is made the same as or
higher than a rate of graff output from the field area averaged
over several cycles of filling and emptying the harvesting unit and
transfer to the vehicle, and a number and speed of operation of the
vehicles is made high enough to avoid substantial waiting periods
between filling of the harvesting unit with graff and transfer of
the collected graff to the vehicle.
[0028] In another preferred aspect, the invention relates to a
mobile harvesting unit for harvesting graff, comprising a
harvesting header (e.g. a direct-cut or swath pick-up type) at a
front of the harvesting unit for removing a crop from a field area,
a threshing unit for separating stalks from a mixture graff, a
mixture of grain, chaff and weed seeds, a storage tank for storage
of the separated graff, and a hitching arm for connection to a rear
portion of a propulsion device, the hitching arm being of inverted
generally U-shape to allow attachment at opposite ends of the arm
to the unit and the propulsion device while extending over the
harvesting header.
[0029] In the harvesting unit of this kind, the hitching arm
preferably supports and guides a mechanical driveling for
transferring mechanical power from the propulsion device to the
harvesting unit, the driveline including a plurality of rotary
shafts joined by constant velocity joints or U-joints to allow the
driveline to adapt to changes of direction of the hitching arm. The
hitching arm may also be used for guiding and protecting hydraulic
tubes for conveying hydraulic fluid under pressure from the
propulsion device to the harvesting unit. These tubes may pass
through an interior channel in the hitching arm.
[0030] In another preferred aspect, the invention relates to a
mobile harvesting unit for harvesting graff, comprising a cutting
head, a threshing unit for separating stalks from graff, a mixture
of grain, chaff and weed seeds, a storage tank positioned above the
threshing unit for temporarily storing graff, an auger bed for
transporting graff to collection areas on opposite lateral sides of
the unit, and a pair of graff elevators, one on each side of the
storage tank, for simultaneously removing graff from the collection
areas of the auger bed and for delivering removed graff to a top of
the storage tank.
[0031] Further, the invention in another preferred aspect relates
to a cleaning mill for graff, comprising a receiving unit for graff
sized to allow a graff transportation vehicle to drive at least
partially therein for dumping a load of graff, a graff conveyor for
feeding graff into the mill as a moving matted layer of
approximately constant thickness (preferably in the range of 1.5 to
3 inches), and elevators for tilting the receiving unit, following
removal of the vehicle, to cause the load of graff to slide to the
graff conveyor.
[0032] Further, in another preferred aspect, the invention relate
to a cleaning mill for graff, comprising an aspirator for blowing
air through a falling matted layer of graff to remove chaff and
light materials leaving aspirated graff containing grain kernels
and heavy materials, a centrifugal separator for removing the chaff
from the air after passing through the curtain of graff, a fan and
ductwork for recirculating air continually through the curtain of
graff and through the separator, a screening unit for separating
grain from remaining materials from the aspirated graff, an outlet
for the separated grain, a mill for milling the remaining materials
to produce millings, ductwork for circulating the millings to the
centrifugal separator, an outlet device for removing solids from
the centrifugal separator for discharge from the mill.
[0033] It will be appreciated that, in the following discussion,
the reference to "grain kernels" or "grain" as the desired product
of the harvesting operation should be taken to include the grain
kernels or seeds of all crops that are harvestable by conventional
combine harvesters, not merely wheat. Such products include, for
example, oats, barley, peas, lentils, rice, soybeans, mustard seed,
canola, rapeseed, etc. The harvesting system of the present
invention can be operated with all such crops.
[0034] Moreover, while the grain kernels are separated from the
graff to leave a mixture of chaff, weed seeds and other materials,
referred to as millings, the components of the millings may
themselves, if desired, be separated either during the cleaning of
the grain in the cleaning mill, or subsequently. Separate outlets
may be provided for the separate components of the millings. Thus,
while the claims of this application may refer to an outlet for
millings, there may in practice be two or more outlets for various
components of the millings, and the term used in the claims is
intended to cover this eventuality.
[0035] It will also be understood that the millings may contain
additional elements such as unthreshed heads, pieces of straw,
dust, leaves, and other harvesting residues and debris, and so the
term should not be limited merely to a mixture of weed seeds and
chaff.
[0036] In the following description, numerical values are often
expressed both in metric units and in non-metric units (the latter
being shown in brackets). In the event of any discrepancy, the
values expressed in non-metric units should be considered
correct.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] FIG. 1 is a schematic sketch illustrating the overall
harvesting method according to a preferred form of the present
invention;
[0038] FIG. 2 is a perspective view of a preferred embodiment of a
harvesting unit suitable for use in the method of the
invention;
[0039] FIG. 3 is side view, with internal elements visualized, of
the preferred harvesting unit of FIG. 2;
[0040] FIG. 3A is a view similar to FIG. 3, showing the threshing
mechanism and graff collection area in isolation;
[0041] FIG. 4 is a side view in cross-section of a hitching arm of
the harvesting unit of FIGS. 2 and 3;
[0042] FIG. 5 is a top plan view of a harvesting unit according to
FIG. 2 and FIG. 3 showing the method of attachment to a
conventional tractor;
[0043] FIG. 6 is a top plan view of an auger bed, shown in
isolation from other equipment, as used in the harvesting unit of
FIG. 2 and FIG. 3;
[0044] FIGS. 7A, 7B, 7C and 7D are simplified cross-sectional view
of the harvesting unit of FIG. 2 and FIG. 3, showing how graff is
lifted into and moved within the graff storage tank;
[0045] FIG. 8 is a side elevation of an alternative preferred
embodiments of the harvesting unit and hitching arm of the present
invention attached to a conventional tractor;
[0046] FIG. 8A is an enlarged view, partly in cross-section, of a
joint in a power transmission line carried by the hitching arm of
FIG. 8;
[0047] FIG. 8B is a top plan view of the harvester of FIG. 8
showing a horizontal section immediately beneath the graff storage
tank and straw walkers, showing the augers used to move the graff
and the direction of graff flow (indicated by arrows);
[0048] FIG. 8C is a top plan view of the harvesting unit of FIG. 8
looking down upon the graff collection tank and showing (by arrows)
the direction of movement of gaff through the tank and removal
chute;
[0049] FIG. 9 is a perspective view of a preferred embodiment of a
cleaning mill suitable for use in the method illustrated in FIG.
1;
[0050] FIG. 10 is a perspective view on an enlarged scale of a
screening unit forming part of the cleaning mill of FIG. 9;
[0051] FIG. 11 is a side elevation of a graff receiving unit and
graff conveyor, on an enlarged scale, forming part of the cleaning
mill of FIG. 9, the receiving unit being in the down position ready
to receive a graff transportation vehicle;
[0052] FIG. 12 is a view similar to FIG. 11, but showing the
receiving unit in the raised position for feeding graff to the
graff conveyor;
[0053] FIG. 13A is a side elevational view of the aspirator, fan
and centrifugal separator forming a closed graff cleaning circuit
and forming part of the apparatus of FIG. 9;
[0054] FIG. 13B is a view similar to that of FIG. 13A from the
other side;
[0055] FIG. 13C is a perspective view of a reel used in the
apparatus of FIG. 13A and FIG. 13B;
[0056] FIG. 13D is a sketch showing a millings discharge pipe
having a cyclone deceleration unit at its free end; and
[0057] FIG. 14 is a side elevation of a cleaning mill, graff
receiving unit and graff conveyor according to a second preferred
embodiment of the present invention showing the graff receiving
unit in an upright position containing a transported load of graff;
and
[0058] FIG. 15 is a top plan view of the cleaning mill (the graff
receiving unit and graff conveyor having been omitted) according to
FIG. 14.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0059] Harvesting Method
[0060] One of the objectives underlying the present invention is to
improve the efficiency of the graff harvesting and cleaning system
described in the McLeod patents mentioned above, as well as
providing a further alternative to the use of conventional combine
harvesters for harvesting grain. The inventors named in the present
application has found that one way of achieving this is to ensure
that components of the system are designed so that harvested
material (the graff) flows constantly and efficiently through the
system without avoidable delays. This has the advantage not only of
maximizing operation efficiency, but also of avoiding the need for
temporary storage of graff and thus avoiding the problems caused by
the poor flow properties of graff.
[0061] As in the McLeod patents, the components of the system of
the present invention comprise: (1) a mobile harvesting unit for
harvesting the crop, i.e. for collecting graff and returning stalks
to the field; (2) a cleaning mill for separating grain kernels from
the remainder of the graff, and preferably for crushing and/or
shredding the remainder of the graff to compact it and to reduce
the viability of the weed seeds; and (3) one or more vehicles
(normally trucks provided with open truck boxes coverable by a
tarpaulin or the like to prevent loss of graff through blowing) for
transporting harvested graff from the harvesting unit to the
cleaning mill.
[0062] As already noted, a particular problem encountered in
dealing with graff is that, while it is not particularly heavy, it
is very bulky compared to the cleaned grain product delivered from
a conventional combine harvester (the amount of graff collected
from a given crop area may be as much as four times higher in terms
of volume than the amount of grain collected by a combine harvester
from the same crop area). Moreover, unlike grain, graff does not
flow easily; it tends to pack, clump, bridge, rat-hole and bind,
making its transfer within and between mechanical equipment very
difficult.
[0063] In view of the problem of excessive bulk, one might think
that a solution would be to provide a harvesting unit with an
internal graff collection container (storage tank) that is as large
as possible to avoid the need for frequent stops to discharge the
collected graff. However, if this is done, the volume of the
collected graff may exceed the capacity of the transport vehicle
(truck) used to transport the graff to the cleaning mill, resulting
in delays and/or the need for additional vehicles. Similarly, if
the amount of graff delivered to the cleaning mill at one time is
too large, there may be a build-up or overflow of collected
unprocessed graff, ultimately resulting in a temporary storage or
termination of harvesting to allow for the graff build-up to be
processed.
[0064] A preferred solution to this problem is to ensure that the
capacities of the various components (harvesting unit, vehicle,
cleaning mill) are matched to allow an even and continuous flow of
graff through the system to avoid the need for temporary storage of
the graff before it is processed. Consequently, the graff-holding
capacity of the harvesting unit should preferably be as large as
possible, but no larger than the capacity of a vehicle used to
transport the graff to the cleaning mill, and the throughput of the
cleaning mill should preferably be such that it may handle a volume
of graff at least as great as the graff holding capacity of a
vehicle used to transport the graff in the vehicle turnaround time
(the time between successive deliveries of graff from the
harvesting unit to the cleaning mill).
[0065] This is illustrated schematically in FIG. 1 of the
accompanying drawings. The drawing is a plan view representing in a
very general way a field area 10, a road (or track) system 11 and a
yard area 12. A harvesting unit 15 (graff harvester), pulled by a
conventional tractor 16, harvests a crop from the field area 10,
returns stalks to the land and collects graff (threshed grain
kernels, chaff, weed seeds, small bits of straw, etc.) inside the
harvesting unit 15 in an internal container (storage tank) until
the container is full. The harvesting unit 15 then stops and
unloads the collected graff into a graff transport vehicle 17
(generally a standard dump truck with an open-topped truck box and
an openable rear silage gate) which, when full, transports the
collected graff 18 to a cleaning mill 20 located in the yard area
12. Here, the vehicle 17 dumps the graff 18 through the entire rear
gate into a graff receiving unit 21 of the cleaning mill 20 and
returns (as shown at 17') to the field area to repeat the cycle.
The capacity of the graff receiving unit 21 should be at least as
large as the carrying capacity of the vehicle 17 so that the
vehicle may unload fully immediately upon arrival at the cleaning
mill so that it is not delayed. If the cleaning mill 20 is intended
to process the graff from several harvester units at the same time,
then the capacity of the cleaning mill must be increased
correspondingly. The graff 18 deposited in the receiving unit 21 of
the cleaning mill passes immediately through the cleaning mill and
is separated into cleaned grain 25 and millings 26 (a mixture of
smaller grain kernels, weed seeds, chaff, and small bits of straw,
etc.) that have been subjected to milling.
[0066] The harvesting unit 15 has an internal graff storage
capacity that should be approximately the same as, or at least no
larger than, the capacity of the vehicle 17 so that the internal
container of the harvesting unit, when full, may be emptied
completely into the truck box of a single vehicle 17. This may be
done by stopping the harvesting unit at a waiting truck, or by
emptying the harvesting unit into a moving truck as both continue
to move (with or without further harvesting). More than one vehicle
may be provided, depending on the distance of the field area 10
from the yard area 12, and the rate of operation of the harvesting
unit 15. Ideally, there should be a waiting vehicle 17 whenever the
harvesting unit 15 is filled and is consequently required to stop.
For greatest economy of operation, only a single vehicle 17 is
required to operate the method continuously, which means that the
time required to fill the container of the harvesting unit with
harvested graff should be approximately the same as the time for
transport, dumping and return of the single vehicle 17.
[0067] This may be expressed in another way. Although the
harvesting unit 15 harvests (collects and delivers) the graff on a
batch basis, it will, on average, have a rate of graff delivery
that can be expressed in units of weight or volume per unit time.
The rate of graff harvesting by the harvesting unit 15 should, for
the most effective and efficient operation, be essentially the same
as the average rate of transport of the graff by the vehicle 17
from the field area 10 to the yard area 12.
[0068] At the yard area 12, the cleaning mill 20 is capable of
processing graff at a certain speed when operating continuously.
This can also be expressed in terms of units of weight or volume
per unit time. For efficient and effective operation, the speed of
processing of the graff should be no slower than the average rate
of graff delivery by the vehicle 17, and no slower than the rate of
graff harvesting by the harvesting unit 15. This ensures that the
various pieces of equipment (harvesting unit, cleaning mill and
delivery trucks) all work as an integrated system.
[0069] Ideally, therefore, in this system, the rate limiting step
should be the harvesting of the crop by the harvesting unit 15.
That is to say, the crop should be collected, transported and
processed as quickly as the crop can be cut and threshed (stalks
removed) by the harvesting unit 15. This means that, if the field
area 10 is physically close to the yard area 12, it may be adequate
to have a single vehicle 17 because it may have the time to
transport, dump and return between each completion of a filling
cycle of the harvesting unit. This is the ideal situation.
Obviously, from time to time, the ideal arrangement will break
down, but the system should be designed to allow such efficient
operation to be the norm. As the distance from the field area to
the yard area increases, more vehicles may be provided. However, as
the separation of the field area from the yard area increases,
there will come a time when it is too expensive or impossible to
provide enough vehicles 17 to maintain the required minimum rate of
collection and delivery of the graff. Often this physical
separation limit is found to be in the order of 6 km. On the other
hand, the physical separation of the field area 10 and the yard
area 12 should have no significant effect on the speed of
throughput of the cleaning mill because this should always be the
same as, or higher than, the rate of crop cutting and graff
collection by the harvesting unit, or several harvesting units if
the mill is intended to service several such units. The relative
capacities and throughputs of the harvesting unit 15, the
vehicle(s) 17 and the mill 20 should be designed and utilized to
ensure that this is so. Trucks of the type normally employed for
hauling grain and the like usually have a capacity of about 21
m.sup.3(750 cubic feet), so the storage capacity of the harvesting
unit 15 and the capacity of the graff receiving unit 21 should
preferably be about the same.
[0070] While this optional organization of the entire system is
desirable, it would still provide problems if carried out with
equipment basically as shown in the McLeod patents. The reason for
this is best described with reference to FIG. 7 of U.S. Pat. No.
5,795,222, which is one of the McLeod patents. This drawing shows a
grain truck 20 having raised sides 21 discharging graff into a
hopper 23 through a small discharge port provided at the lower
central part of the read raised side of the truck. The hopper is
then emptied by a large grain auger 22 into one of several surge
storage bins 24 provided for temporary storage. A further auger 26
then transfers graff at a constant rate from one of the bins 24 to
the upper entrance 54 of the yard plant (cleaning mill) 48.
However, because of the poor flow properties of the graff, it is
difficult to discharge the material from the truck through the
small discharge port in the rear tailgate of the truck, and
difficult to get the graff to flow from the lower conical ends of
the surge storage bins. This creates inefficiencies and
difficulties that can cause delays in the cleaning of the graff
while attempts are made to cause the graff to flow properly
again.
[0071] Solutions to this problem, at least in its most preferred
forms of the present invention, make use of ways of causing graff
to flow that have been devised by the inventors. The inventors have
observed that graff can be caused to flow without difficulty in the
following ways:
[0072] 1) Graff can be caused to slide bodily or tumble down a
slope (or chute) inclined at a suitable downward angle, provided
that it is not impeded in any way, e.g. by inwardly tapering or
inwardly stepped walls provided at the lateral sides of the sloped
surface or chute. This avoids the problem encountered when a
delivery truck of the type shown in the McLeod patents is provided,
i.e. a truck having a small opening or delivery port provided in
the tailgate (which is typical of grain delivery trucks). The
tailgate impedes the sliding or tumbling action of the graff and
provides a "choke point" that impedes smooth graff flow.
[0073] 2) A quantity of graff can be removed from the bottom of a
pile of graff, or a container (e.g. a silo) full of graff, provided
that essentially the entire lowermost layer (or an inner layer) of
the graff is removed all at one time, rather than just a part of
the graff from the lowermost layer (or any inner layer) as has been
done conventionally. This can be achieved by moving a conveyor
surface or a series of elongated transverse elements (rakes or
slats) beneath the pile or contained body of graff, while
preferably maintaining the remainder of the body of graff
essentially stationary in some way. If essentially the entire
lowermost layer of the graff is removed, the remainder of the graff
can move downwardly without binding or bridging. If it is desirable
to prevent the remainder of the graff from moving as the lowermost
layer is withdrawn (which is the case if a constant supply of graff
is to be delivered to a piece of equipment, such as the cleaning
mill), the remainder of the graff may be confined within a
container or behind a retaining wall, or the body of graff may be
supported on an upwardly sloping surface so that the weight of the
body of graff prevents it from following the movement of the
removed layer.
[0074] 3) Graff can be caused or "encouraged" to flow bodily from
one point A, e.g. a point of delivery within a container, to
another point B by moving an upper layer of a body of graff from
point A towards point B. This is best used in conjunction with 2),
i.e. the moving of a lower layer of material from point A to point
B (without of course attempting to prevent the movement of the body
of graff as is done in some forms of 2). This can be done, for
example, by providing augers at an upper level of the body of
graff, and is particularly useful within a graff harvesting unit
where graff is collected a the front of a container and has to be
moved to an outlet region or well at the back of the container.
[0075] 4) Graff can be conveyed in a current of air of suitable
volume and velocity, but this may cause some separation of the
components of the graff. However, such separation is desired in
certain parts of the system, e.g. in the cleaning mill, so movement
of graff in this way tends to be confined to such system parts.
[0076] 5) Graff can, of course, be moved bodily as a single mass,
e.g. on a horizontal moving surface (e.g. a conveyor). This is
useful, for example, for emptying graff from a rear well of a
harvester unit, or the like.
[0077] A practical application of these observations has already
been suggested in FIG. 1 of the present application in that the
cleaning mill 20 is provided with an integral graff receiving unit
21. This is sized to receive the entire contents of a delivery
truck, which can consequently dump its entire load of graff through
its open tailgate (which may be hinged at the top or bottom to
allow it to be swung out of the way). As will be apparent firm the
following description of preferred versions of the cleaning mill
described below, the receiving unit is specially designed to raise
the deposited graff to an elevated entrance of the cleaning mill
without encountering problems caused by the poor flow
characteristics of the graff.
[0078] Thus, an important aspect of the present invention is to
avoid the need for temporary storage of the graff by allowing for a
full load of graff from at least one delivery vehicle to be
delivered at once to a graff receiving unit of a cleaning mill,
which unit can then deliver a regular supply of the graff to an
elevated input opening of a cleaning mill. If this is done, and if
the rate of cleaning of the graff in the cleaning mill is
sufficiently rapid, the graff may be transferred from the
harvesting unit, directly to the delivery vehicle and then directly
to the cleaning mill without any intermediate storage of any kind,
thus avoiding problems encountered with the use of conventional
storage silos and the like. Temporary storage may of course be
provided by the delivery vehicles themselves, in that if the
harvesting rate were to exceed the cleaning rate temporarily, the
temporary excess of graff could be held in a sufficient number of
delivery vehicles, if needed, and provided such vehicles were
available. Clearly this is to be avoided if possible, but could
provide a temporary solution to overflow problems.
[0079] Another important aspect involves the design of the
harvesting unit to make best use of the principles of graff flow
described above.
[0080] Yet another important aspect of the invention involves the
design of the cleaning mill that makes efficient use of movement
and separation of graff, at least in part by the use of air
currents.
[0081] Yet another important aspect of the invention involves the
design of the harvester unit that allows it to be towed by a
conventional vehicle, e.g. a tractor. While this has nothing to do
with the flow properties of graff itself, it is important for the
overall economy of the present invention as such vehicles tend to
be less expensive to manufacture and to operate. A special hitching
arm has been developed for this purpose.
[0082] With these basic concepts in mind, a description of
preferred embodiments of the novel components of the graff
harvesting system of the invention will be provided below.
[0083] Improved Graff-Harvesting Harvesting Unit
[0084] For even greater efficiency and effectiveness of harvesting,
improved harvesting units have been developed according to the
present invention. These harvesting units may be used in the
harvesting method indicated above or in other harvesting methods,
e.g. as disclosed in U.S. Pat. No. 5,873,226.
[0085] Various graff-harvesting harvesting units are disclosed in
U.S. Pat. No. 5,794,423. These harvesting units are effective, but
they are expensive to manufacture and can be cumbersome and
difficult to operate. Moreover, because of the difficulties in
making graff flow evenly, the material flow through the known
harvesting units may not always be optimum. The preferred
harvesting unit of the present invention overcomes these problems
to a desirable extent.
[0086] Farmers in recent years have become used to self-propelled
harvesting units, such as conventional combine harvesters. Several
of the harvesting units disclosed in U.S. Pat. No. 5,794,423 are of
the self-propelled kind. However, the required motor, driving
controls and steering mechanisms add considerably to the cost of
such vehicles. U.S. Pat. No. 5,794,423 also discloses non-powered
(pull-type) harvesting units (see, for example, FIGS. 4 to 10 of
the patent), but these are of the "wrap-around" kind, i.e. the
harvesting header is positioned in front of a propulsion unit
(tractor), while the remainder of the harvesting unit is positioned
to the side or rear of the propulsion unit. This leads to a
mechanically complicated, cumbersome and expensive designs.
[0087] The harvesting unit of the present invention is based in
part on the concept of providing a pull-type unit for
cost-reduction (most farmers already have their own tractors or
other suitable propulsion units) while avoiding the complexity of
the wrap-around design by towing the harvesting unit at the rear of
the propulsion unit. However, this creates a problem in that, if
the harvesting unit is towed behind a tractor, there is difficulty
in providing a suitable means of attachment between the two since
the harvesting header (particularly a direct-cut header) is
necessarily positioned immediately behind the tractor hitch point,
making a conventional tow bar impossible to use and blocking access
to the tractor's mechanical and hydraulic power supplies. The
header also has a cutter bar that must be raised, and this imposes
a further constraint on any towing system. This difficulty has been
overcome according to the present invention by providing a
harvesting unit having a novel hitching arm.
[0088] A first preferred embodiment of the improved harvesting unit
15 is shown in perspective view in FIG. 2 of the accompanying
drawings. As shown, the harvesting unit 15 comprises a harvesting
header 30, that may be of either the direct-cut type (e.g. a
conventional header, normally 7.3 to 9 m (24 to 30 feet wide)) or a
swath pick-up header (normally 4.25 m (14 feet) wide). A crop
feeder housing 31, e.g. a chain feeder, feeds the cut crop
rearwardly to the harvester body containing the unit's internal
threshing mechanism, described in more detail later, where the cut
crop is separated into stalks (which are returned to the field as
straw) and graff (a mixture of grain, chaff and weed seeds, etc.).
The body of the harvester unit also contains a graff holding
container or tank 33 to which graff is transferred after being
collected from the threshing mechanism. When the tank 33 is full,
the unit 15 is stopped (or unloaded on-the-move), and the graff is
transferred to a transport vehicle 17 (not shown in this view, but
see FIG. 1) via an unloading auger 34. The harvesting unit 15 is
pulled on unpowered wheels 32 by a conventional tractor 16 (not
shown in this view, but see FIGS. 1 and 3) via a hitching arm 35
that not only acts as a tow bar, but also supplies mechanical and
hydraulic or pneumatic power to the harvesting unit 15 from the
tractor and provides a steering function.
[0089] In the harvesting unit of the invention, at least in
preferred forms, several factors combine to make the use of the
illustrated hitching arm possible. Unlike a regular combine
harvester, the harvesting unit does not contain a grain cleaning
apparatus (because it is intended to harvest graff), which means
that the threshing cylinder 30 may be positioned closer to the
ground. The grain feeder housing 31 from the cutter head to the
threshing cylinder may also be made quite short as a result (e.g.
about 1.2 m (four feet)), and this allows the harvester to be
located closer to the tractor, and means that the cutter head does
not have to be raised very much in the stowed condition. In
consequence, the hitching arm 35 may be quite short and the cutter
head 30 easily fits within the "crook" of the hitching arm in the
raised condition.
[0090] In a first embodiment, the hitching arm 35 has a closed-in
hollow tubular design and, in side view, as best shown in FIG. 3,
it has a centrally-raised shape (referred to for convenience in the
following as an "inverted U-shape", although it is realized that
this is a very loose description --a more accurate description
would be that the hitching arm is elongate with two opposite ends;
the arm ramps or rises upwardly from each end towards the centre of
the arm, and the arm has a short, elevated, generally horizontal
section between the ramped or raised sections at in the middle of
the arm). The inverted U-shape allows the crook C (upward bend) of
the hitching arm to extend over the top of the harvesting header
30, with enough clearance to allow the header to be raised to the
elevated (stowed) position shown in FIG. 3. This generally means
that the crook C, at its highest point, must be elevated by a
distance of at least 3 m (10 feet) from the ground. The length of
the hitching arm 35 must also be suitable to prevent it fouling the
harvesting header 30 during normal harvesting, even when the
harvesting unit 15 is steered out of direct alignment with the
tractor 16 (as will be explained later). This usually means that
the hitching arm must project horizontally by at least about 6.5 m
(21 feet). However, the hitching arm should preferably be no longer
than necessary to achieve this objective in order to minimize
turning moments (that may overwhelm the steering mechanism of the
tractor if they become too great) when the hitching arm is moved to
one side of the tractor or the other. For comparison, a hitch that
would have to be used for a pull-type combine harvester would have
to be longer and stronger, i.e. at least 10 m (33 feet) in length,
because of the added weight of the combine. This makes it extremely
difficult or impossible to control side forces in a non-aligned
cutting operation. The maneuverability would therefore be lost with
such a machine.
[0091] Since the hitching arm must pull quite a heavy load (the
harvesting unit plus harvested graff), and since it is of inverted
approximately U-shape as shown, forces encountered during
harvesting will tend to pull the ends 37 and 38 of the hitching arm
towards or away from each other. The hitching arm should therefore
be made sufficiently strong and rigid that significant flexing of
this kind is prevented. In the illustrated embodiment, the hitching
arm is made of three main tubular elements of square cross-section,
36, 39 and 40, that are welded together at their interconnecting
joints 41 and 42. A heavy gauge steel box construction is suitable
for this purpose.
[0092] The hitching arm 35 is shown in isolation and in
longitudinal cross-section in FIG. 4. The interior 44 of the
hitching arm 35 forms an enclosed channel which may be used, if
desired, to accommodate hydraulic and electrical lines (not shown)
extending between the tractor and the harvesting unit. Generally,
the hydraulic system includes three hydraulic sets, one for
pivoting the header 30, one for turning the header, and the third
for raising the header. The hydraulic cylinder 69 used for raising
and lowering the harvester head is visible in FIG. 3.
[0093] The top edge of the arm is used for guiding a mechanical
driveline 45 that conveys rotary motion from the tractor's
mechanical drive to the harvesting unit where it is used to drive
the harvesting header 30 and other components. The driveline
consists of several straight shafts 46, 47, 48, 49, 50
interconnected at their ends by means of constant velocity joints
51, 52, 53, 54 and 55. Alternatively, the joints may be interlaced
pairs of U-joints. The ends of the driveline may also include
constant velocity joints 56, 57 for connection to the mechanism of
the harvesting unit and the tractor, respectively. Suitable
bearings 58, 59, 60, 61, 62, 63, 64, 65 are provided on the upper
surface of the hitching arm to secure the driveline and to ensure
that the shafts rotate smoothly. The constant velocity joints
employed for this purpose are preferably capable of operating at
angles up to 17.degree. and of handling power transmission of up to
150 kW (200 hp). The use of constant velocity joints in the
driveline not only means that the driveline may follow the inverted
U-shape of the hitching arm 35, but also (because of the constant
velocity joints 56, 57 at the extreme ends of the driveline) makes
it possible that the hitch arm may be moved out of direct alignment
with the tractor or the harvesting unit without damaging the
mechanism.
[0094] The driveline may be enclosed by an elongated cover 68
(shown in part in FIG. 2) in the form of an inverted channel
section that fits over the upper edge of the hitching arm.
[0095] As shown in FIG. 5, the hitching arm 35 is connected to a
drawbar 70 of the tractor 16 via a conventional hitch 71. At the
opposite end, the hitching arm 35 is connected to the harvester
unit 15 via a "hydra-swing" hitch, which includes a pair of
hydraulic cylinders 72 and 73, attached to the body of the
harvester unit 15, that allow the hitching arm 35 to be kept in
direct alignment with the tractor 16, or moved to one side or the
other, as shown. This sideways movement, which can be controlled by
the operator of the tractor, allows the tractor itself to remain
largely clear of the unharvested crop, and allows the harvesting
unit to be swung from one side of the tractor to the other to
facilitate back-and-forth harvesting of the crop. On the other
hand, by positioning the harvesting unit directly in line with the
tractor, the overall width of the equipment may be minimized (for
passing through gates, and the like).
[0096] At its opposite end, the hitching arm 35 is connected to a
frame element 74 of the harvesting unit for rotation about a
generally vertical axis by means of a vertical pivots 75 (see FIG.
2). This allows the harvesting unit 15 to remain in a
forward-facing direction, i.e. facing in the same direction as the
tractor, when moved to one side or the other out of direct rearward
alignment with the tractor. The unpowered wheels 32 on which the
harvesting unit 15 rides are not steerable, and these wheels tend
to keep the harvesting unit moving in the same direction as the
tractor, even when the harvesting unit is moved to one side of the
tractor or the other.
[0097] As will be appreciated, the tractor 16 both powers and
maneuvers the harvesting unit 15. For most applications, a standard
125 kW (165 horse power (hp)) tractor with a 95 kW (125 hp) power
take off (PTO) with three hydraulic couplings and suitable
transmission speeds will be suitable to operate the harvesting unit
15.
[0098] As mentioned earlier, graff has proven to be an extremely
difficult material to handle because it does not flow easily and
because it is bulky and is produced in large amounts. The threshing
and storage mechanism of the illustrated harvesting unit 15 is
intended to overcome the difficulty of collecting and processing of
graff.
[0099] As shown in FIG. 3, a chain-type crop feeder housing 31
conveys cut crop material into the interior of the harvesting unit
15 where the crop material encounters a rotating threshing cylinder
77 and a perforated concave 78 that, in conjunction with a rear
flanged beater roll 79, subject the crop material to a severe
threshing action. The separated grain, chaff and weed seeds (i.e.
graff) fall through the perforated concave 78 and collect on an
auger bed 80, i.e. an inner flat surface of the harvesting unit
beneath the concave provided with several narrow augers extending
front to back. The rest of the crop (stalks and remaining grain,
etc.) is then passed from the cylinder 77 to an arrangement of
straw walkers 82 which separate any remaining graff from the
stalks. The graff separated in this way also falls onto the auger
bed 80. In the harvester unit 15 of the present invention, the
feeder house 31 and straw walkers 82 may be made considerably
shorter than those used in a conventional combine harvester (e.g.
only 1.2 m (4 feet) long for the feeder house, and 1.8 m (6 feet)
long for the straw walkers, as opposed to 3 m (10 feet) in a
combine harvester). This allows a more compact unit to be
constructed, and the short feeder housing 31 allows the cutter bar
of the header to fit under the crook C of the hitching arm when in
the raised position. The threshing cylinder 77 is also very low,
i.e. much closer to the crop than in conventional harvester
designs. This allows the hitching arm 15 to be made quite short
(e.g. 6.5 m (21 feet)). The shorter length makes possible the
unique shape of the hitching arm and, in turn, the unique shape
makes it possible for the header to be raised and lowered inside
the crook of the hitching arm.
[0100] The stalks are moved by the straw walkers to the rear of the
harvesting unit 15, where they are discharged onto the ground
through a discharge opening 83 either as a swath or as small pieces
formed when the stalks encounter an optional straw chopper/spreader
84. As noted, the graff separated by the straw walkers 82 falls
through the straw walkers to the bed 80 of the harvesting unit.
[0101] The threshing and graff collection section of the harvester
unit 15 is shown in isolation and increased size in FIG. 3A, in
particular showing the various pulleys and drive belts and chains.
The feeder of the feeder housing 31 is driven by feeder drive belt
180, and the cylinder 77 is driven by cylinder drive belt 181.
Element 182 is a variable drive belt driven by the main pulley 183.
The beater 79 is driven by a beater drive belt 184, and chopper 84
is driven by chopper drive belt 185. A secondary counter shaft 186
is driven by a secondary shaft drive belt 187. The straw walkers 82
and auger bed 80 are driven by drive belt 188. Element 189 is a
conveyor drive chain.
[0102] The auger bed 80 is shown in plan view of FIG. 6 in
isolation from the other elements of the harvesting unit. The bed
80 slopes upwardly slightly from front to rear, but the graff, as
it collects, is moved from below towards the rear of the bed by a
set of several rotating augers 84 provided just above the surface
of the bed 80 and orientated in parallel from the front of the bed
to the back and across the entire width of the bed. The graff is
thus moved bodily towards the rear and encounters a transverse
channel 85 containing a pair of coaxial cross augers 86, 87 that
move the graff in opposite outward directions shown by arrows A and
B towards vertical paddle elevators 88, 89. The storage tank 33 of
the harvesting unit 15 (see FIG. 2) is positioned immediately above
the collection bed 80 with enough vertical clearance for the augers
84 and the collected graff.
[0103] It is to be noted that, unlike many combine harvesters, the
harvesting unit 15 lacks grain cleaning apparatus and a mechanism
for returning unthreshed heads to the threshing cylinder. This
makes it possible to design a harvesting unit having a low profile
because the storage tank 33 may sit low over the auger bed 80, and
it also results in a power saving since material is not being
recirculated through the threshing mechanism. This further
simplifies the harvesting unit of the present invention and makes
it mechanically more reliable than a conventional combine
harvester. In the apparatus of the invention, unthreshed heads are
collected with the graff and become part of the millings, as
described later.
[0104] As noted, the graff from the auger bed 80 is elevated to the
height of the top of the storage tank 33 by a pair of paddle
elevators 88 and 89 (see FIG. 3 and FIG. 6) for the graff located
at the ends of the trough 85 on each side of the storage tank 33.
FIGS. 7A, 7B, 7C and 7C are diagrams showing how the graff is
raised into the tank 33, moved therein and removed therefrom. As
shown in FIGS. 7A and 7B, the graff elevators 88 and 89 are
positioned on the outside of the unit at their bottom ends and they
extend upwardly and forwardly. The fact that two elevators 88 and
89 are provided means that a large volume of graff from the
collection bed 80 can be accommodated at opposite sides of the
tank, ensuring a regular flow of graff from the collection bed and
into the storage tank at opposite sides, as shown by the arrows in
FIG. 7A. At a point midway between the lower and upper ends, the
elevators pass inside the tank 33, the entrance areas being shown
by shading in the drawing. The elevators discharge within the tank
33 at the upper front end. A pair of inwardly-directed augers 81
move the graff to the middle of the tank where another auger 90 is
provided to help distribute the material to the rear.
[0105] FIG. 7C shows the inside of the storage tank 33 at a point
behind the elevators 88, 89. The tank has a unique shape designed
to minimize problems caused by the poor ability of graff to flow.
Various augers are provided to keep the graff moving as required
within the tank. The tank is provided with a horizontal leveling
auger 90 at the top to move the graff backwards and to prevent the
formation of a central peak. A pair of rotating agitators 91, 92
are provided lower in the tank to help prevent bridging within the
body of graff. These agitators are generally horizontal but slope
slightly upwardly towards the rear as shown in FIG. 3. At the
bottom of the tank 33, a pair of delivery augers 94, 95 are
provided to move the bulk of the graff rearwards towards a well 96
(see FIG. 7D), i.e. a deeper section of the tank, formed at the
rear of the tank (see FIG. 3). The lower wall 190 of the tank 33 is
in the form of an inverted V so that the graff is directed toward
transport augers 94 and 95. The well 96 forms the lowest collection
point for the graff and is thus the last section of the tank to be
emptied by an unloading auger 34, the bottom end of which is
positioned at the bottom of the well 96. The auger 34 is actually
made up of two co-operating augers, i.e. a vertical auger
positioned in the well 96 that lifts the graff out of the well 96
and a horizontal auger that moves the graff to downward facing,
preferably flexible, delivery spout 97. The well 96 forms a hopper
which contains an exposed inclined section of flighting 99 which
draws graff into the vertical, then horizontal, sections of the
unloading auger. The unloading auger may be centred along the top
of the storage tank 33 during harvesting, and may be swung to
either side or to the rear for discharge of the graff into a
waiting vehicle 17. The unloading augers are preferably of large
diameter compared to those for unloading grain from combine
harvesters. For example, the vertical auger may have a diameter of
41 cm (16 inches) or more and the horizontal auger may have a
diameter of 35.5 cm (14 inches) or more. This allows for a very
rapid emptying of the tank, i.e. in the region of three
minutes.
[0106] All of the various augers and agitators are driven by
mechanical transmissions (e.g. belts and pulleys) taking power from
the rotating shaft carried by the hitching arm 35.
[0107] The storage tank 33, which is preferably of approximately 21
m3 (750 cubic feet) in capacity (at least twice the size of the
collection bin of the largest convent ional combine harvester) and
(as noted above) preferably has the same size as a truck box of the
vehicle 17, is preferably provided with a particular shape that
facilitates the storage and movement of the graff. As shown in
FIGS. 7A, 7B, 7C and 7D, the front wall 27 and lower parts of the
side walls 28, 29 of the tank slope inwardly from the lop to the
bottom. The angle of slope is preferably made at least 50.degree.
relative to the horizontal, so that the graft slides towards the
bottom of the tank and does not become trapped at the base of the
front and side walls in the form of stagnant piles. This feature
makes use of the observed ability of graff to slide freely down a
slope having a suitable angle of inclination. The sloping front
wall 27 also allows the tank to clear the hitching arm 35 and
allows better weight distribution.
[0108] Although the storage tank 33 is designed to hold a
substantial amount of graff, the low density of this material means
that the tank does not have to be unusually strong, so there is no
need for cross-bracing of the walls, or the like. In fact, the
sculptured (tapering) shape of the tank increases its structural
strength relative to a rectangular tank of the same capacity.
[0109] The tank preferably has an open hatch 98 (FIG. 7C) on the
top surface that may be covered when desired by a roll-back
tarpaulin (not shown) or the like. This allows access to the
interior of the tank for maintenance and to clear blockages.
[0110] It has been found advantageous to coat the inside of the
tank 33 and auger chutes with a paint that forms a low friction
surface in order to minimize binding of the graff at the sides of
the tank. Preferably, the paint should provide a surface having a
co-efficient of friction of less than about 0.45. Paint containing
powdered graphite (e.g. paint sold by Acu Mech Sys Enterprises
Ltd., under the trademark SLIP-PLATE.RTM.) is particularly
effective in this way.
[0111] FIG. 8 is a side view of an alternative preferred embodiment
of the harvesting unit and hitching arm of the present invention.
In the description of this embodiment, elements that are identical
or equivalent to those of the previous embodiment are identified by
the same reference number with an added prime (e.g. 15 becomes
15').
[0112] It will first of all be noted from FIG. 8 that the hitching
arm 35' is made up of four sections rather than three, these
sections being 36', 39', 40' and an additional vertical section 39a
at the tractor end of the hitching arm. The presence of the
additional section gives the arm a greater approximation to the
inverted U-shape mentioned earlier and provides greater "headroom"
C' above the harvesting header 30' to allow the header to be raised
fully to the inactive position, and also allows more room for the
harvesting header in the operational position during swinging of
the harvester unit 15' out from one side of the tractor 16' or the
other. Depending on the materials of construction, this embodiment
may encounter slightly more flexing during use than the hitching
arm of the previous embodiment, the total amount of flexing being
about 0.3 m (1 foot) between the opposite ends, and so this degree
of flexing must be accommodated by the mechanical drive line 45'.
This can best be done by providing U-joints at the points where the
drive line bends to follow the shape of the hitching arm, and also
by providing slip joints (splined telescopic sections) within the
driveline itself to accommodate lengthening and shortening actions
of the line. As a alternative to using U-joints for this purpose,
it is also possible to use gearbox designs to achieve the required
change of angle. A suitable gearbox design is shown in enlarged
partial section in FIG. 8A, which shows the driveline 45' at the
junction of arm sections 36' and 39'. The gearbox 801 consists of a
housing 802 containing mutually-meshing rotatable beveled gears 803
and 804. The lowermost gear 804 is attached to driveline section
47' for rotation therewith and the uppermost gear is attached to
driveline section 48' for rotation therewith. The angle at which
the gears are mutually arranged creates the change of direction of
the driveline 45' as it passes through the gearbox 801. A small
degree of angular misalignment of the gears 803 and 804 is possible
to accommodate flexing, and more is permitted by the presence of
constant velocity joint 805 on one side of the gearbox and a slip
joint 806 on the other side. The gearbox must be strong enough to
transmit the power provided to the driveline 45' without distortion
or overheating.
[0113] At the point of attachment of the hitching arm 35' to the
tractor 16', a ball joint 807 is provided to allow sharp turns, and
a gearbox 808 may be bolted to the tractor body.
[0114] In this embodiment, the hitching arm 35' is attached to the
harvesting unit 15' at pivot 75' which is placed no more than about
1.2 m (4 feet) in front of the rotational axis of the wheels 32'.
This positioning is important for two reasons. Firstly, the close
proximity of the pivot 75' to the wheels means that easier turning
of the harvesting unit by the hydraulic cylinders 72' and 73' (See
FIG. 8C) can be achieved. Secondly, the centre of gravity of the
harvesting unit is slightly to the front of the wheels when the
unit is empty, but moves rearwardly of the wheels as the unit is
filled during harvesting. This reduces the downward force on the
hitching arm and allows the hitching arm to be of a lighter design
than would otherwise be the case.
[0115] In this embodiment, the hydraulic lines from the tractor 16'
to the harvesting unit 15' preferably follow the outside of the
hitching arm 35' (rather than run through the hollow interior) for
easier servicing, and the clearance of the cylinder can be adjusted
from inside the tractor (along with all of the other hydraulic
functions, preferably using a single-handed joystick design).
[0116] The harvesting unit 15' of FIG. 8 differs from the
harvesting unit 15 previously described in several respects, as
described in the following.
[0117] Firstly, instead of equipping the floor of the tank 33' with
a series of parallel augers, as in the previous embodiment, in
order to move the collected graff towards the rear of the tank, a
"live floor" 810 is provided, i.e. an endless belt made up, for
example, of mutually spaced transverse slats driven by chains. This
makes use of the principal mentioned earlier that graff may be
moved by moving or removing the entire lowermost layer of a body of
the graff, i.e. a lowermost layer that extends completely across
the width of the body of graff--in this case substantially the
entire width of the tank 33'. In the previous embodiment, the
intention was to deliver the graff as quickly as possible to a
large rear well 96 positioned at the rear of the tank 33 from which
the graff can be augered out as shown in FIG. 7D. In this second
embodiment, the approach taken to graff removal is different.
Instead of the large well 96, the tank 33' is provided with a
shallow transverse well or channel 96' enclosing a quite large
(e.g. 50 to 60 cm (20 or 24 inches)) generally horizontal
transverse auger 820 or alternatively a conveyor belt). The live
floor 810 slopes upwardly to the rear and thus the bulk of the body
of collected graff tends to remain towards the front of the tank
33' and the movement of the live floor feeds a constant supply of
graff into the channel 96' when the auger is operated, thus
reducing the risk that binding will take place above the auger, or
blockage of the channel 96' will occur.
[0118] The slats circulate around a plate 811 acting as a false
floor of the tank and the slats themselves may be provided with
flexible strips at the front to provide a sweeping action over the
false floor. The chains 812 used to drive the slats (generally
there are at least 2 and preferably 3 parallel chains) provide an
open structure that is self-cleaning as it moves around the false
floor. An alternative possibility would be to use a flexible (e.g.
rubber) conveyor belt instead of the slats and chains, but material
tends to build up underneath such arrangements, so they are usable
but no preferred.
[0119] The transverse auger 820 in the channel 96' feeds a
side-mounted hinged enclosed conveyor 815 or chute that is used to
transfer the collected graff to an adjacent vehicle (not shown).
The fact that the conveyor 815 is hinged means that it can be
raised or lowered to a point just above the vehicle box. A conveyor
is used rather than an auger to provide bodily transport of the
graff supplied by the auger to prevent binding and blockage. The
arrangement also allows the tank to be emptied quickly, e.g. within
about 3 minutes or less.
[0120] A pair of augers 817 and 818 are provided at the top of the
tank 33' in order to level the pile of graff (not shown) collected
in the tank. These help to move the body of collected graff towards
the rear of the tank. A sensor (not shown) is provided to indicate
when the tank 33' is full so that graff does not overflow into and
build up above the channel 96' before the auger 820 can be operated
to begin removal of the graff from the tank. Such overfilling could
promote binding and blockage. The harvesting is interrupted when
the sensor indicates that the tank is full and emptying commences,
assuming that emptying is not being carried out simultaneously with
harvesting (i.e. into a moving accompanying vehicle).
[0121] In this embodiment, the tank may be made larger than the
previous embodiment and the slope of side walls 28' and 29' is made
a minimum of 60.degree.. The interior of the tank is again coated
with low friction paint. The increased capacity may be obtained by
increasing the height of the unit to 4.25 m (14 feet) and
increasing its length (e.g. by approximately 1.5 m (5 feet)). This
may result in a tank 33' having a volume of approximately 31.8
m.sup.3 (1120 cubic feet). While the tank 33' is generally made of
sheet metal, such as steel, the tank may, alternatively, be made of
plastic material as the graff load is light despite the large
volume.
[0122] Cleaning Mill
[0123] To further improve the efficiency and effectiveness of the
harvesting method, an improved cleaning mill 20 (often referred to
as a yard plant) has been produced.
[0124] The cleaning mill 20 is illustrated in perspective view in
FIG. 9, from which it can be seen that the mill consists of several
main parts, namely a drive-in graff receiving unit 21 (which acts
as an open receptacle for the graff delivered by a vehicle) and
graff conveyor 100, an aspirator 101 for removing chaff and light
material from the graff, a millings collection unit 102, a
screening unit 103, and a rolling mill 104. The aspirator 101 is
powered by a Written Pole motor 105, or alternatively a diesel
motor, and the mill is controlled by a computer module 106
(PLC).
[0125] Graff is delivered to the cleaning mill 20 directly from the
field by a truck 17 (see FIG. 1). In the past, attempts were made
to pour the graff through a small door positioned in the rear wall
or gate of the truck box in the same manner that grain is delivered
to a grain storage area. However, as noted above, graff does not
flow in the same way as grain, and once deposited in a pile, it is
difficult to pick up and convey to the cleaning mill. To overcome
this problem, the illustrated cleaning mill has a drive-in graff
receiving unit 21 that allows a truck to back directly into the
receptacle (as suggested by the tire tracks 107 shown in FIG. 9)
and to dump the graff by unhooking the rear gate and raising the
truck box (as illustrated in FIG. 1).
[0126] The graff receiving unit 21 is a grain receptacle in the
form of a flat box 108 having a slightly ramped bottom wall 109 and
two longitudinal side walls 110, but no end walls. The unit is
aligned with the more steeply upwardly ramped graff feeding
apparatus or conveyor 100 forming an inclined surface. FIGS. 11 and
12 are side views showing the receiving unit in a receiving
position (FIG. 11) awaiting a graff delivery, and in the upturned
operational position (FIG. 12), in which the receiving unit acts as
a chute so that graff is urged onto the bottom end of the graff
conveyor 100. The tilting of the receiving unit is controlled by
hydraulic cylinders on each side of the unit (although only one is
shown in FIGS. 11 and 12).
[0127] In the case of the graff conveyor, the ramped surface 113 is
provided with a rotating drag chain conveyor 112 that moves up the
ramp and carries graff to the upper end 114. A rotating delivery
roller 115 at the upper end of the drag chain conveyor functions to
beat back graff coming up the conveyor and equalize out the graff
across the width of the box (usually 10 feet wide) so that only a 4
to 8 cm (1.5 inch to 3 inch) mat of graff proceeds to the top 114
of the graff receiving unit. The thickness of the mat is determined
by the adjustable distance from the drag chain 112 to the roller
115. The roller is positioned a short distance (a few centimeters)
above the upper end of the ramped surface 113, and is provided with
projecting teeth 116 spaced along and around the circumference of
the roller. The delivery roller is rotated rapidly by a motor (not
shown) and, as noted, feeds a "mat" or carpet of graff (i.e. a
continuous strip of even width and thickness) into an upper
entrance 117 of the aspirator unit 101 (see FIG. 9). The graff
conveyor 100 serves the purpose of lifting the graff from ground
level to an elevated position from which it may be subjected to
aspiration as it falls vertically back to ground level within the
cleaning mill. A second function of the drag chain conveyor 112 is
to meter (by changing the speed of the conveyor driven by a
variable speed motor) the correct volume of graff delivered to the
top 114 of the receiving unit and into the aspirator 101.
Therefore, by varying the speed of the conveyor and by varying the
distance between it and the roller 115, acceptable amounts of graff
can be metered into the aspirator 101. It is important that the
entire width of the aspirator (3 m (10 feet) for 91,000 liters
(2,500 bushels) per hour) is matched to the width of the receiving
unit to facilitate the continuous material flow capability of the
entire machine.
[0128] The aspirator 101 is shown in greater detail and in
isolation from the other equipment in FIG. 13A, 13B and 13C. The
mat or carpet of graff passes through an entrance 117 to the
aspirator unit and directly encounters an aspirator reel 300. The
reel is shown in isolation in FIG. 13C and it will be seen that a
number of rubber cogs 301 (three inches in height) are arranged
along the surface of the reel with a slight twist (preferably about
10.degree.) in the axial direction to facilitate entry of the graff
into the aspirator. The rubber cogs 301 form an air seal preventing
air under pressure in the aspirator 101 from escaping through the
inlet 117. It will be seen from FIG. 13A that there is no free
space within the entrance 117 to allow graff to settle and clog the
apparatus. Once graff passes through the entrance 117, it is
immediately taken up by the reel which delivers it to the
aspirator. As a stream 118 of graff falls vertically through the
aspirator, it is subjected to a lateral airflow 119 that impinges
on one side (the front) of the stream and passes through to the
other side carrying away chaff and other light materials. The
aspirator has six drop zones defined by baffles 120. The air flow
through each drop zone is controlled by a manually adjustable
damper 121 at the drop zone's inlet. In each drop zone, the air
stream passes through the falling graff.
[0129] The airflow 119 is created by a fan 122 which moves air
along a lower duct 123 to a front end of the aspirator, and then,
after passing through the falling stream of graff 118, returns the
air (and entrained chaff and light materials) through an upper duct
124. If too much air is entering into the front of the aspirator
101, air can be bled off directly into the return air flow by a
manually operated gate 302. A centrifugal (cyclone) separator 125
removes the chaff and light materials from the air flow before the
air returns to the fan 122. The separated mixture of chaff and
light materials (referred to as "millings") is conveyed by a
material conveying fan 126 (see FIG. 13B) to a conveying tube 127
and may be delivered to a suitable storage pile, container, or
vehicle via a pipe 128 (see FIG. 13D) attached to the conveying
tube 127. The pipe 128 (which may be as long as 15 to 21 m (50 to
70 feet)) has a small cyclone unit 129 at its remote end acting as
a decelerator for the millings to prevent widespread distribution
of this light material, and allowing it to collect into a pile
135.
[0130] The operation of the separator cyclone 125 is governed by
the fan 122 (see FIG. 13A) operating at a volume of about 340
m.sup.3 (12,000 cubic feet) per minute (for 91,000 liters (2,500
bushels) of graff per hour throughput). The fan forces air through
the aspirator 101 and along duct 124 to the separator 125. The
millings material contained in the airflow upon reaching the
separator clings to the outer wall of the separator by centrifugal
force and moves to a final discharge portal 303. The discharge
through portal 303 is assisted by air equalization tube 304 shown
in FIG. 9 and by the discharge fan 126 shown in FIG. 13B. Within
the separator 125, clean air in the middle of the unit is returned
to the fan 122 by duct 305 shown in FIG. 13B. The cleaned air is
driven by the fan 122 and returns to the aspirator 101 via ducting
123 to a front side of the aspirator. The ducting forms a closed
loop for the air to recirculate between the centrifugal separator
125 and the aspirator 101. Dust build-up within the closed loop is
avoided by the introduction of make-up air from the rolling mill
172 and screening unit 103.
[0131] The heavy material 130 (aspirated graft, which contains the
grain and weed seeds, etc.) collects at the bottom of the aspirator
101 and is removed by a horizontal cross auger 131, then raised by
paddle elevator 132 (see FIG. 9) to a drop tube 133, from which it
falls into the screening unit 103 for separation into the desired
cleaned grain product and other a secondary product comprising the
remaining organic material.
[0132] The screening unit 103 is shown in detail in the perspective
view of FIG. 10. The material delivered from drop tube 133 falls
into a split (bi-directional) leveling auger 140 positioned at the
upper end of the screening unit which serves to distribute the
material evenly across the screens. The unit consists of an open
framework 141, retaining a number of downwardly sloping oscillating
screens 142 arranged in two groups or "shoes." The opening size of
the screens decreases from the uppermost to the lowermost screen,
so that larger particles are collected on the upper screens and
smaller particles descend to the lower screens. A separation of the
aspirated graff based on particle size is thus obtained. The top
shoe 143, contains three scalping screens 144, 145 and 146, through
which the grain passes and large material is removed. The first
screen 144 of this shoe directs stones and larger debris to a
hopper 307 from which it exits the machine. The second and third
screens, through which grain kernels drop, direct larger crop
material to a trough 147. From the top shoe, the grain flow is
divided and dropped onto two screens on the bottom shoe 148. The
bottom shoe 148 contains two sets of three inclined, oscillating
sizing screens. The grain passes over the screens while the
"screenings" (weed seeds, small kernels, etc.) pass through and are
gathered in a trough below the screen. The grain then drops through
a plenum 160 with a cross-flow air stream where dust is removed
from the grain and conveyed through a dust delivery tube 150. The
grain falls into a cross-conveyor 161, which delivers the grain 25
into a hopper 165. From the hopper, the grain is conveyed to
storage.
[0133] Screenings from the two top shoe screens and the six bottom
shoe screens are gathered in troughs and routed via drop tubes to
the bottom shoes screenings collection trough. From this trough,
the screenings are delivered into a paddle elevator 170, which
lifts the screenings to a drop tube 171, from which the screenings
fall into an intake hopper of a rolling mill 172 (see FIG. 9) where
the screenings are rolled. From the bottom of the rolling mill 172,
air is drawn along with the rolled screenings into a duct 308
connected to an intake 309 of the cyclone separator 102. Within the
separator 125, the rolled screenings from the mill 172 are
re-combined with the light material from the aspirator 101 and the
dust from the plenum 160 of the screening unit 103 delivered via
dust delivery tube 150.
[0134] As already noted, solids (millings) separated from the air
by separator 125 are drawn by a portion of the air through a duct
173 into a material-conveying fan 126 (FIG. 13B). The fan helps to
remove the millings and air from the separator 125 in a continuous
manner without disrupting the centrifugal separation effect within
the separator. This has proven to be in improvement on the usual
air lock provided for removal of solids from a separator. The fan
125 also makes it possible to project the millings a considerable
distance from the machine via conveying tube 127 and pipe 128 to
the small cyclone decelerator 129. The millings, which consist of
just about all of the organic matter from the graff other than the
grain kernels are dropped into a pile 135 for storage. Weed seeds
in this material have been passed through the rolling mill 172 and
thus are no longer viable (i.e. they are inert). Moreover, small
screened grain kernels are also crushed, making them more
digestible for cattle. The collected millings are therefore a
valuable product that may be used as animal feed or for other
purposes. Despite this rolling step, only a single material (other
than the cleaned grain) is discharged from the mill because of the
recirculation of rolled material to the intake of the separator
unit where it is mixed with light materials from the aspirator. Of
note is also the final air bath applied to the cleaned grain just
before it is discharged from the mill. This air bath removes fine
dust that is also recirculated to the intake of the separator
125.
[0135] Of course, if desired, the rolled material and/or the dust
from the air bath need not be returned to the separator, but could
be discharged independently merely by rerouting the indicated
piping. The material from the screens (screenings) is by itself a
high protein feed material.
[0136] A particular advantage of the cleaning mill is that, if
desired, it can be operated automatically, essentially without an
operator. Computer control ensures normal operation of the mill at
all times.
[0137] An alternative embodiment of the cleaning mill is shown in
FIGS. 14 and 15. In this embodiment, the graff receiving unit 21'
(which forms an open receptacle for the graff) and the graff
conveyor 100' are essentially the same as in the previous
embodiment and allow graff to be deposited as a full load from a
truck by upending the truck box, dumping the graff load, and
delivered in a constant stream to a laterally elongated upper inlet
117' of the cleaning mill without binding or blocking and without
the need for intermediate storage. However, upon passing through
the inlet 117', the graff enters a transverse channel 900
containing a cross-directed gathering auger 901 (which preferably
has a diameter of 43 cm (17 inch)). The purpose of this auger is to
reduce the width of the graff flow from that of the graff conveyor
100' (approximately 3 m or 3.3 m (10 or 11 feet)) to that of the
width of the cleaning mill itself, which is somewhat narrower
(approximately 143 cm (56 inches)). By this means, the both the
cleaning mill and the conveyor may be designed to have optimal
widths for their intended functions, even though those widths may
differ.
[0138] In this embodiment, the screening unit 103 of the previous
embodiment is incorporated into the main body 905 of the cleaning
mill 20'. This makes the cleaning mill more compact and easier to
operate. As shown in simplified schematic form in FIG. 14, upon
leaving the transverse channel 900 at the central opening 975, the
graff falls onto a grain pan 907 provided with a reciprocating
action that tends to stratify the graff into components of
different density and levels the graff into an even carpet 908
having a width of 0.6 to 1.2 m (2 to 4 feet). The grain pan moves
the graff forwards until it falls onto a cleaning shoe 909. The
cleaning show includes an upper chaffer screen 910 and a lower
grain sieve 911 (both of which are of adjustable mesh size) that
are reciprocated back and forth in an opposed motion. A short
extension sieve 912 is also provided at the distant end of the
chaffer 910. This can be adjusted independently of the chaffer, and
can be raised at an angle to slow down the flow of material, if
desired. The chaffer and grain sieve each preferably have a surface
area of about 1.7 m.sup.2 (17.9 sq. ft.). The mesh size of the
chaffer is larger than that of the grain sieve. As the graff passes
through the shoe 909, large chaff, stalks, cut heads and stones are
separated mainly by the chaffer 910 and then intermediate contents
(e.g. weed seeds, small chaff, stalk parts, etc.), are separated at
the grain sieve 911. Essentially only grain 915 itself passes
through the grain sieve 911 and falls to a collection pan 916 that
has sloping front and rear walls directing the grain to a central
trough 917 for removal by a cross auger 918 through a grain exit
919.
[0139] As the graff is separated into its components in this way,
air is blown upwardly and outwardly through the shoe 909 as
indicated by arrows A. This air flow suspends essentially all of
the graff components except the grain and heavy objects such as
stones. In fact, as the graff drops onto the shoe 909 from the
grain pan 907, it encounters a blast of air forceful enough to blow
away essentially everything but clean grain kernels of the desired
size (and heavy objects, such as stones). This reduces the amount
of separation required to be carried out by the shoe 911 itself.
Both the suspended chaff and the heavy objects proceed to a cyclone
separating unit 920. The suspended chaff is carried by the air
flow, whereas the heavy objects are moved by the reciprocating
action of the shoe sieves into the inlet 921 of the cyclone
unit.
[0140] The airflow is created by a fan 925 (e.g. a 16.5 kW (22 hp)
centrifugal fan creating a throughput of 400 m.sup.3/min (4,000
cubic feet/minute)) positioned within the cleaning mill beneath the
graff conveyor 100'. The fan directs air into conduit 926 leading
to the cleaning shoe 909, but an adjustable diverter 927 is
provided upstream of the shoe to direct a portion of the air into a
bypass conduit 930 as indicated by arrows B. The air from the
bypass 930 nevertheless also enters the cyclone unit 920 with the
air that has passed through the cleaning shoe 909. The diverter
allows the airflow A through the shoe to be made appropriate for
cleaning the graff (designed to blow away everything below kernel
removal) while still allowing a high rate of airflow through the
cyclone unit 920. The diverter 927 may be either manually
adjustable or automatically controlled based on the rate of feed of
graff into the cleaning mill.
[0141] A stone cleanout door 932 is provided at the bottom of the
cyclone unit 920 to allow stones and other large or heavy objects
to be removed periodically from the bottom of the cyclone unit
where they tend to collect as they are not removed by the
airflow.
[0142] The cyclone unit 920, by virtue of the spiral flow of air
there through and the density of the suspended chaff, causes the
suspended chaff to congregate around the inside wall 935 of the
unit so that clean air that is substantially free of chaff and
other solids may exit the unit through a central opening 936. The
chaff, propelled by a further flow of air, exits a chaff delivery
port 937 located at an outside lower region of the cyclone unit.
The clean air is recirculated directly to the fan 925 via ducting
940 (see FIG. 15), although a certain amount of clean air from the
outside may be introduced into the recirculated air, e.g. through
an elongated slot provided adjacent to the graff entrance 117', to
replace air escaping with the chaff and to reduce the build-up of
dust (about 90% recirculation is usual).
[0143] The solids exiting chaff delivery port 919 contains chaff
proper, weed seeds, unthreshed heads, and small grain kernels. As
shown in FIG. 15, this is conveyed through ducting 950 to a high
speed centrifugal material-conveying fan 951 provided with
paddle-like blades. The fan has a hammering, impacting or chopping
effect that reduces the size of large items and tends to crack,
nick or crush weed seeds and small grain kernels (thus making them
less liable to germinate). The fan is preferably operated at a
speed of about 3293 rpm, giving the fan a velocity at its blade
tips of about 440 km/hr and a throughput of about 57 m.sup.3/min
(2000 cubic feet/minute). Obviously, variations (e.g. .+-.10%) of
these speeds and velocities may be employed, provided the desired
material conveying and seed cracking effects are obtained. The
material exiting the fan is then conveyed through tubing 952 to a
desired location where it is discharged to form an open pile (not
shown) (or it may, if desired, be discharged into a silo or other
form of container, however the crushed millings adhere to
themselves and cake together so the material tends not to blow away
from an open pile). The millings form a good quality animal feed
similar in nutrient content to hay. The fan 951 and tubing 952 may
convey the solids up to a distance of about 60 m (200 feet) from
the cleaning mill, depending upon the power of the fan 951. The fan
951 acts to both convey the separated solids and to crush them. It
acts at a fast rate of throughput and is rarely subject to
blockage, plugging or failure for other reasons. This is all
achieved at a reasonable cost in power to operate the fan.
[0144] In a preferred form of this embodiment, as shown, a single
motor 955 is used to drive both the air fan 925 and the
material-conveying fan 951. This is preferably a written pole
(single phase) electric motor of 30 to 37.5 kW (40-50 hp).
Approximately eight additional small electric motors (of
approximately 1.5-2.25 kW (2-3 hp) each) are required for the
complete operation of the cleaning mill. Advantageously, all these
motors may be designed to operate on single phase power that is
most readily available on farms and in remote areas.
[0145] The cleaned grain exits the grain delivery port (propelled
by the positive air pressure in the cleaning mill or extracted by
an auger) and is delivered by an auger to a storage container (e.g.
one or more silos--not shown).
[0146] The cleaning mill of this embodiment maintains a constant
recirculation of air and a constant stream of graff into the mill
and constant streams of cleaned grain and the remaining
constituents from the mill. The illustrated unit is capable of
processing 91,000 liters (2500 bushels) of graff per hour. The
receiving unit 21' is capable of holding at least 27,000 liters
(750 bushels) of graff A single load from a truck can therefore be
processed in about 20 minutes.
[0147] The mill can be essentially left to operate without
supervision. The truck operator can use a remote control device to
lower the receiving unit as the truck approaches, dump the load of
graff, and then set the cleaning mill in operation and leave for
another load. The mill may be computer controlled to raise the
receiving unit in stages to feed the graff conveyor appropriately,
and to run all of the fans and motors until a sensor indicates that
all of the graff has been processed. The unit may then shut itself
off automatically, awaiting the next load.
* * * * *