WO2000074467A1

WO2000074467A1 - Air flow harvester vacuum stripper front

Info

Publication number: WO2000074467A1
Application number: PCT/AU2000/000610
Authority: WO
Inventors: Robert William Amos Taylor
Original assignee: Robert William Amos Taylor
Priority date: 1999-06-03
Filing date: 2000-05-29
Publication date: 2000-12-14
Also published as: AUPQ074999A0

Abstract

An airflow harvester vacuum stripper front (1) for a mobile support structure attached to a combined harvester/header. The vacuum stripper front (1) comprises an elongated and rotatable support means (2), in the form of a drum, extending transversely across the direction of travel of the harvester vacuum stripper front (1). The rotatable support means (2) has attached to it a plurality of airflow enhancing stripping elements (3) with teeth or serrations. The rotatable support means (2) is capable of being driven by a driving means, within the mobile support structure. A cowl (10) at least partially surrounding the rotatable support means (2) defines an intake section (12) disposed forward and adjacent the rotatable support means (2). The crop entrained by the air flow induced by the rotatable support means (2) passes through the intake section (12), via a deceleration section (9) to a separating turning vane (6) and a soft curtain section (15). The unwanted material flows out of the mobile support structure with the exhausted air.

Description

AIR FLOW HARVESTOR VACUUM STRIPPER FRONT

This invention relates to the mechanical harvesting of crops. Mechanical harvesters are used for the harvest of a wide variety of cereal and legume crops, including traditional grain crops such as wheat, oats, barley, and rice, as well as more brittle crops such as peas. This invention is particularly concerned with the devices known as "fronts" that are fitted to mechanical harvesters to harvest the desired portion of the crop which may contain a greater or lesser amount of undesired material. This invention also relates to smaller tractor mounted models for harvesting crops grown in rows, these row crops include herb flowers and foliage also vegetable seeds etc.

Crude mechanical harvesters have been thought to have been used as early as Roman times. However it was not until the mid eighteenth century in England that the forerunners to current mechanical harvesting machines were proposed. This lead to the grant of the first patent on a reaping machine in England in 1799. In Australia the first development of mechanical harvesters took place in the 1840's and led to the development of a stripper comb and rotary beater principal which was widely used for a century in cereal harvesting in Australia.

The Australian Harvesters were distinguished from the European and American devices which used cutter bars to take in the whole crop. The Australian strippers basically used fixed steel combing teeth with a rotary beater that forced the crop into the teeth. Whilst these harvesters were eminently suitable for Australian cereal crops they were found not to be suitable for tangled, weedy or green crops or for use in crops such as rice.

The mid 1980's saw the development of the first so called grain stripping fronts for mechanical harvesters. These devices differed significantly from known harvesters by utilising the concept of upwardly combing teeth mounted across the front of the harvester. The development that led to the commercial introduction of this type of stripper front for harvesters was the invention of flexible "keyhole" shaped stripping elements. The stripper front is based on the concept of stripping the crop from the plant whilst leaving the stalks or other material standing in the field. The typical configuration of the stripper front includes an inlet cone or nose that pushes the crop slightly forward ahead of the tooth carrying drum which rotates in a forward and upward direction relative to the direction of travel of the harvester. Harvesters of this type and the teeth used on the stripper drums are described for example in GB Patent Application 2176685, International Patent Application WO 88/05626,

International Patent Application WO 92/0337.

These so called stripper fronts have been commercially successful and are in widespread use. They offer significant reduction in the amount of unwanted material that is harvested with the grain or the like as well as at least partially threshing the grain so that very little straw is taken into the harvester for separation.

Despite these advantages the stripper fronts still share a disadvantage with traditional knife fronts. In both cases the mechanical contact with the crop can cause the rain and even complete grain heads to be dislodged form the crop prior to collection. That is, the grain is thrown forward of the harvester and falls on the ground under the influence of gravity. It has been estimated that commonly 10% or more of product can be lost in this manner depending upon the type of crop and it's condition at the time of harvesting.

Additionally the efficiency of the harvester is related to the amount of undesired material that is processed through the harvester during the course of extracting the desired product. The amount of processing required to extract the desired product can also have an impact on the quality because of the possibility of smashing, cracking and bruising where extensive processing is required. It is an object of this invention to provide an improved stripper front for use with a mechanical harvester or smaller tractor mounted models that will overcome, or at least ameliorate, one or more of the foregoing shortcomings.

Accordingly, in one aspect this invention provides a harvester front for use with a mechanical harvester, including an elongated drum mounted for rotation about an axis generally transverse to the direction of travel of the harvester, said drum including a plurality of crop- engaging teeth distributed across and around the drum, a cowl at least partially surrounding the drum on a leading side and defining an inlet disposed forward and adjacent the drum, means associated with a trailing side of said drum to contain a flow of air within the shroud and means to induce from the rotation of said drum a flow of air through said inlet from the area forward of the drum.

Various drum orientations are possible. For example, the drum can be arranged horizontally and extend through to perpendicular to the direction of travel in the generally traditional configuration. In other configurations, multiple drums can be used arranged horizontally in V- shaped orientations or multiple angled drums can be used.

The air flow from adjacent the forward side of the drum where the teeth or fingers first contact the crop results in the entrainment of any dislodged material in the air flow so that it is carried into the stripper front.

One embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic cross section of a stripper front according to this invention;

Figure 1 A shows the schematic cross section of Figure 1 with operational characteristics;

Figure IB is a partly sectioned view of the stripper front shown in Figure 1;

Figure 2 is a schematic plan view of the stripper front shown in Figure 1 ;

Figure 3 is a perspective view of a drum and tooth aπangement following part of the stripper front of Figure 1 ;

Figure 4 shows the engagement of the fingers shown in Figure 3 with air control fingers forming part of the arrangement shown in Figure 1;

Figure 5 shows the fingers shown in Figure 3 as they pass air outlet associated with the rear opening of the stripper front shown in Figure 1;

The drawings show a stripper front 1 for use with a harvesting machine (not shown) of conventional type. The harvesting machine can essentially be of any type suitable to thresh the portions of a crop removed by the harvester front 1 to recover the desired product and separate it from waste. In the following description the desired product will be referred to as "grain" and the waste as "MOG" (material other than grain). Harvesters of this type all include provision usually through hydraulic pressure for the driving of the drums(2, 8), conveyors(16, 17 & 19) and the like associated with stripper fronts.

The stripper front(l) includes a cylindrical drum rotor(2) mounted for rotation about a generally horizontal axis through to the perpendicular axis, transverse to the normal operational direction of movement of the front (1) (to the left as viewed in Figure 1). Drum (2) includes a number of rows mount supports and teeth or fingers (3) which extend generally parallel to the axis of rotation of drum (2). As best seen in Figure 3 or 4 the teeth have a generally triangular profile with interposed at the base of each tooth(3). Teeth of this type are described in Australian Patent Specification 88663/91.

Also as best seen in Figure 3 the teeth(3) are arranged in parallel rows that extend helically around the drum/rotor(2). The drum/rotor(2) is mounted within a chamber(9) partially defined by a cowl(lθ). The cowl(lθ) extends from in front of the drum rotor(2) to define a front edge(l l), of an inlet(12) that extends transversely across the stripper front(l). The cowl(lθ) includes a rounded nose portion(13) that gently displaces the crop (Figure 1A) downwardly with the passage of the stripper front(l). Chamber(9) opens into an expansion area(14) behind drum/rotor(2). A soft curtain(15) depends from cowl(lθ) into the expansion area(14). The soft curtain(15) can for example be formed by a piece of rubber plastics or the like. Directly below curtain(15) a pair of conveyors(16, 17) are positioned to convey grain transversely of the stripper front or in other words parallel to the axis of drum/rotor(2). The conveyors (16, 17) are disposed across the rear of the stripper front(l) and operate in opposite directions so as to carry material that falls onto the conveyors (16,17) toward a center aperture(18). A third conveyor(19) then moves the material rearwardly into the input region of the harvesting machine (not shown). It will be apparent that this conveyor mechanism (16, 17, 19) may be confirmed to suit the particular harvesting machine. A row of stationary air control fingers(20) is mounted across the stripper front(l) at the rear of drum/rotor(2).

These fingers are best seen in Figure 4. These fιngers(20) are correspondingly shaped to the fingers(3) on the drum/rotor(2) so that the two sets of fingers(3, 20) intermesh as they pass. This is best seen also in Figure 4. The purpose of the air control fingers(20) is to prevent a substantial egress of air from chamber(9) around the rear side of drum/rotor(2). Rather, the bulk of the air flow is directed out of the rear of the stripper front(l) through vents(22) above convey or( 19). A Concave Shroud(23) prevents turbulent air, grain, vegetable seeds and or herb flowers/foliage from being drawn out of the front(l) by the rear portion of the drum/rotor(2). This controlled, prevented air intake results in enhanced quantity of air and crop being drawn in through the front intake position(12) of the front(l). The Concave Shroud(23) is positioned below fingers(20) around the rear portion of drum/rotor(2). The concave shroud(23) preferably provides a confined chamber below the control fingers(20) and the drum/rotor(2) (figure 1. la). The remaining within the confined chamber(24) is accelerated by the rotating drum and fingers resulting in an air pressure drop generating a partial vacuum, within the confined chamber(24) enhancing air and crop intake through the front section(12). This Concave Shroud(23) directs accelerated air flow to region 24 behind the drum/rotor(2). A corrugated element(25) shown in Figure 5 is attached to the edge of the Concave Shroud(23) to direct the air flow exiting region 24 through outlets 25. It will be apparent that the corrugations(25) coπespond to the spaces between teeth 3 as best seen in Figure 5. This air flow is directed so as to agitate grain (not shown) in the path of the stripper front(l). In practice this air flow is directed forwardly at about 45° so as to impinge the ground more or less directly below inlet(12).

In use the stripper front operates as follows. Drum/rotor(2) is rotated in the conventional manner in an upward direction as viewed in Figure 1. In addition to action of the fingers(3) stripping grain and or herb flower/foliage from the crop in the traditional manner and directing it into chamber(4) the rotation of drum/rotor(2) with fingers and supports(3) also generates a significant air flow into inlet(12) from the region immediately in front of the drum rotor(2). This flow of air is directed into chamber (4) but is largely prevented from exiting the chamber(4) around the rear of drum rotor(2) by the air control fingers 20. The bulk of the air flow is therefore directed through expansion chamber(14). The flow of air form the area in front of drum/rotor(2) and adjacent rounded nose(13) results in any grain that is dislodged by contact with the nose(13) or fingers(3) being entrained in the air flow and carried into chamber(4). The entrained material which includes grain and MOG passes into expansion chamber(14) where it naturally decelerates due to the expanding volume. The heavier grain has a higher momentum and thus impacts curtain(15) and falls onto conveyors (16, 17). Most of the dust and lighter MOG remains entrained in the air flow and passes out of the rear vent(22). The grain and MOG that lands on conveyors(16, 17) is carried to conveyor(19) to the feed to the harvesting machine where it is processed in the known manner.

The flow of air generated by the passage of fingers and supports(3) in the region 24 adjacent Concave Shroud(23) is directed by outlets 25 to the ground in the area immediately below inlet(12). This results in the agitation of grain on the ground or grain that is falling towards the ground. This significantly increases the amount of grain that is entrained in the flow of air to inlet(12).

Claims

AIR FLOW HARVESTOR VACUUM STRIPPER FRONTClaims:

1. Rows of stripping fingers arranged helically around the drum/rotor.

2. The 30/45 preferred angle of the stripping fingers.

3. Expansion chamber to decelerate harvested crop and air.

4. A soft curtain to direct dust impacting crop into a transporting medium.

5. Conveyor belts used in a stripper front.

6. Strategically placed separator wall and turning vanes.

7. The Concave Shroud which controls and contains the harvested crop, also increases the confined chamber and enhances air and crop intake.

8. The exhausted air flow carries with it much of the dust and light M.O.G (material other than grain).

9. Confined chamber.

10. Feed beater is in the form of a cylindrical drum with conical end sections.

11. Smaller models for harvesting vegetables seed and herb flowers, herb foliage for example, for harvesting fragile crops grown in rows. Claim 1:

The teeth or fingers including mount supports(3) have a two-fold function. They generate the air flow and also effect the stripping of the crop. The mount supports including the teeth(3) are preferably arranged in rows extending across the drum/rotor(2), or in other words in a direction generally parallel to the axis of rotation. In a further preferred form of the invention the mount supports including the teeth or fingers(3) are arranged in rows that extend helically around the drum/rotor(2). This results in the mount supports and fingers(3) across the drum sequentially engaging the crop as opposed to a conventional straight line of fingers which simultaneously engage the crop.

This helical arrangement of the mount support and teeth or fingers(3) has been found to significantly reduce the power consumption and smooth the operation of the front. This is because a relatively smooth continuous power is required as each portion of each helix sequentially engages the crop as distinct from the pulsed power requirements of linear parallel rotating rows. Additionally, the helical arrangement results in a smoother feeding of the material through the harvester so that the subsequent mechanical handling is at a smoother continuous level, rather than being pulsed due to the pulsed input of the crop from the front. In the preferred embodiment the actual width of crop across the front that is in contact with the fingers is typically one to 1.5 meters across a drum of the order of 12 meters in width.

Claim 2:

The mount support and teeth or fingers(3) are preferably formed from a relatively rigid material and are bent along their length so that the free ends project forwardly in the direction of the rotation. The fingers(3) are preferably formed by two straight sections that meet at the bend. The angle of the bend is preferably about 30/45° . In the currently preferred embodiment teeth of the kind having a slot shaped cut-out between the fingers are used and the bend is preferably located at about the center of the rounded portion of the slot, to slightly inward of the slot. The bent tooth arrangement has been found to provide improved performance thought to result from the grain or grain heads being "cradled" during the upward movement of the fingers(3) to more effectively strip the grain from all sides of the stem. The preferred form of the fingers also generates a higher air flow volume and velocity which improves the capture of grain and the separation of grain form MOG. This preferred angle of the fingers(3) delivers the crop in an upward trajectory into the deceleration cowl(lθ)

The crop dislodged by the action of the fingers(3) is also entrained in the air flow through the cowl(lθ).

Claim 3:

Preferably the speed of the air flow is rapidly reduced in an expansion chamber(9) defined by the cowl(lθ).

Claim 4:

A soft curtain(15) is preferably provided following the expansion chamber(9) to direct impacting grain onto a transporting medium such as a conveyor belt(16,17). The conveyor belt(16,17) transports the crop inwardly toward the feeder/beater(8) to the feeder house of the harvesting machine. Claim 5:

Another feature of the invention is the use of conveyor belts(16,l 7 & 19) in a stripper front.

Claim 6:

The air flow from the expansion chamber(9) can be changed in direction prior to impacting the curtain(15) to improve separation of the entrained crop from the MOG. This is preferably achieved by strategically placed separation walls and turning vanes(6). The air flow direction is changed which results in the path length of the air flow being increased which allows greater time for deceleration of the flow.

The changes in direction are preferably achieved using a series of spaced vanes(6) that project from the cowl(lθ) into the air flow. The vanes(6) are preferably angled at up to 90° to the incident air flow. The vanes(6) are preferably arranged in opposed banks so that the flow is directed toward a central region. As a result more of the grain is directed to the central region of the curtain(15) and subsequently to the region of the centrally located feeder/beater(8) which directs the grain to the feeder house of the harvester. This reduces the loading in the central region of the air flow. Consequently, the downstream air flow tends to diverge so that a large change in air flow direction is achieved due to the vanes(6) and subsequent pressure equalisation. By the use of suitable geometry, this direction change is used to separate the heavier grain from MOG which remains in the air flow and is carried out the exhaust(22).

It has been found that the traditional combing action of the stripper fingers combined with the directing of the air flow carrying the harvested material described above is highly effective in separating the grain from material other the grain (known in the industry as MOG). Claim 7:

Another feature of the invention is the Concave Shroud(23), which is to control and contain the harvested crop by its trough or recess like construction, during the transition from the stripper finger(3) to the conveyor(16, 17 & 19). The Concave Shroud(23) prevents turbulent air currents and harvested crop from being drawn out of the front(l) by the rear portion of the rotor/drum(2) and lost to the ground. The rotation of the support mounts and fingers(3), throughout the confined chamber(24) between the drum rotor(2) and the inner surface of the concave shroud(23), achieves a reduction in air pressure to create a partial vacuum within the confined chamber(24). Resulting in enhanced air and crop intake through the front section(12). The concave shroud(23) controls when the air and crop are draw to the drum rotor(2) through the inlet(12). This enhanced air and crop intake to the stripper fingers(3) results in a more effective harvesting action, making it possible to harvest herb flowers and herb foliage and vegetable seeds for example. The drawing in motion helps capture delicate crops and prevents crops from being blown away from the stripper finger(3) within the front section(12).

Claim 8:

The exhaust(22) allows the air flow to carry with it much of the dust and light MOG. Which is the unwanted part of the harvesting process and expels it outside the harvestor. This is further reduces the amount of processing the harvesting machine itself is required to do and thus further reduces power consumption to provide corresponding reduction in fuel used and improved productivity and the quality of the harvested crop. Claim 9:

Another option can be fitted to the confined chamber(24)for harvesting certain crops. Air can be prevented from exiting the expansion chamber(14) between the fingers(3) and the drum rotor(2) by a second set of correspondingly shaped air control or cut off fingers(20). The air control or cut off fingers(20) are preferably stationary fingers extending across the width of the drum/rotor(2) having apertures corresponding to the shape and size of the fingers(3) mounted on the drum/rotor(2).

Preferably, a Concave Shroud(23) extends beyond the air control or cut off fingers(20) to define a rear opening in the stripper front(l) adjacent the trailing side of the drum/rotor(2). The Concave Shroud(23) adjacent the rear opening is preferably arranged so as to direct the air flow(25) generated by the movement of the fingers(3) from the position of the air control or cut off fingers(20) to the end of the cowl(lθ) forward of the rear opening. In a preferred configuration, a series of air outlets(25) can be formed along the edge of the Concave Shroud(23) to control the direction of the air flow. This flow from the rear of the opening(25) is used to agitate the loose grain on the ground so that it is entrained in the air flow to the inlet opening(12) of the front. In practice, by directing this flow from the rear opening at least partially toward the ground it is possible to recover grain that has fallen to the ground that would otherwise be completely lost.

Claim 10:

Preferably, the feeder/beater(8) of this invention is in the form of a cylindrical drum with conical end sections. The feeder/beater(8) is mounted for rotation about an axis normally transverse to the stripper front. The feeder/beater(8) is positioned centrally below the impact curtain(15) described above. Cross feed conveyors(16, 17) are positioned on either side of the feeder/beater(8) to feed material from the outer regions to the center. The conical ends of the feeder/beater(8) allow the conveyors(16, 17) to be directed toward the central axis of the feeder/beater(8) rather than to the front of the drum as in the case of prior art feeder/beater(8). This is of particular advantage because it allows the feeder/beater(8) to be located relatively further forward thus reducing the overall width of the stripper front(l). The overall width is an important consideration because of the weight of the stripper front and the load imposed on the mountings with the harvester. The feeder/beater(8) is provided with transversely extending beaters extending outwardly from the surface. These can be in the form of resilient flaps and may be somewhat inclined to the axis of rotation.

Claim 11:

The stripper front of the present invention has application not only to large harvesters for broad acre applications but also to smaller tractor mounted models (figure 6) and also self propelled models which are used for various crops and crop locations. Some applications of the small machines are for especially fragile crops for example the harvesting of vegetable seeds from onions and cauliflowers grown in rows for example.

This invention also relates to harvesting herb flowers and foliage grown in rows(figure 6).