EP2844056A1 - Combine harvester with a transverse separating system - Google Patents

Abstract

A combine harvester (10) comprises threshing apparatus (17), a separating system (18) and a grain cleaning system (19). The threshing apparatus and separating system are arranged in series to sequentially receive and process a cut crop stream. Grain separated from the crop stream falls through respective concave grates (27, 32, 33, 44, 45, 46) in the threshing apparatus and separating system. The separating system (18) comprises a plurality of transverse separating rotors (41, 42, 43) which rotate in the same direction as one another. Each separating rotor comprises a plurality of retractable fingers (70) which retract into the rotor when at the top of the rotor and extend radially outward when at the bottom of the rotor so as to convey the crop stream under the rotors and eject crop residue from the rear of the separating system.

Description

DESCRIPTION

COMBINE HARVESTER WITH A TRANSVERSE SEPARATING SYSTEM

[01] The invention relates to separating systems for combine harvesters which are positioned downstream of threshing apparatus.

[02] For many decades, self-propelled combine harvesters have been used by farmers to harvest a wide range of crops including cereals, maize and oil-seed rape. Typically, a combine harvester cuts the crop material, threshes the grain therefrom, separates the threshed grain from the straw, and cleans the grain before storing in an onboard tank. Straw and crop residue is ejected from the rear of the machine.

[03] Combines of the transverse threshing type comprise a threshing cylinder which rotates on a transverse axis and serves to thresh a harvested crop stream. Grain and chaff separated in this process falls under gravity through a grate onto an underlying thresher pan which is driven in an oscillating manner to convey the grain and chaff rearwardly to a rear edge from where the grain and chaff falls under gravity into a cleaning unit. The remainder of the crop stream from the threshing process is conveyed rearwardly from the threshing cylinder into a separating system. During the separating process further grain and chaff is removed from the straw and falls under gravity through a grate onto an underlying separator pan which is also driven in an oscillating manner to convey the grain and chaff forwardly to a front edge from where it falls under gravity into the cleaning unit. The straw by-product from the separating system is ejected from the rear of the combine.

[04] One common separating system involves a plurality of straw walkers which are aligned longitudinally on a rising incline and oscillate so as to 'walk' the crop stream upwardly and rearwardly. Separated grains fall through a grating in the floor of the straw walker onto the separator pan whilst the remaining straw passes over the rear edge and out of the machine.

[05] Straw walkers do not significantly damage the straw which is often collected and baled as a by-product for bedding. However, the separation capacity of straw walkers is limited thus limiting the capacity of the whole machine. [06] In another known separating system employed more commonly away from Western Europe, one or more axial rotors are aligned longitudinally within cages. Conveying elements on the rotor(s) feed the crop stream around the rotors in a rearward direction in a spiral path. The interaction between the conveying elements and the outer cage perform a separating action wherein separated grain falls through the cage. The residue straw is ejected from the rear of the rotor(s) and out of the machine.

[07] Axial separating systems do provide a superior separating capacity to straw walker systems but this comes at the cost of inferior quality straw output and significantly higher power consumption.

[08] There remains a desire to reduce power consumption in combine harvesters whilst maintaining a good separating capacity and good straw output.

[09] In accordance with the invention there is provided a combine harvester comprising threshing apparatus, a separating system and a grain cleaning system, the threshing apparatus and separating system arranged in series to sequentially receive and process a cut crop stream, wherein grain separated from the crop stream falls through respective concave grates in the threshing apparatus and separating system, said grain being conveyed to the cleaning system, the separating system comprising a plurality of transverse separating rotors which rotate in the same direction as one another, each separating rotor comprising a plurality of retractable fingers which retract into the rotor when at the top of the rotor and extend radially outward when at the bottom of the rotor so as to convey the crop stream under the rotors and eject crop residue from the rear of the separating system.

[10] Although well understood in the field of combine harvesters, for clarification, use of the term 'threshing' hereinafter should be understood as relating to the act of separating grain or seed from the plant from which it originates. Use of the term 'separating' hereinafter should be understood as relating to the act of separating the threshed grain or seed from the crop stream to allow the grain or seed to be cleaned and stored with minimal straw content. Despite serving primarily to thresh the crop stream, threshing apparatus may separate a proportion of the threshed grain therefrom by the provision of underlying concave grates for example. Likewise, separating apparatus may demonstrate a small degree of threshing action upon any unthreshed ears present in the output of the threshing apparatus upstream. [11] By providing a separating system with a plurality of transverse separating rotors having retractable fingers, a low cost and convenient alternative form of separating system can be offered. Initial testing has shown that such a system demonstrates good separating capacity and a high quality straw output. Furthermore, and perhaps more importantly, the power consumption of a system in accordance with the invention Is significantly lower than known axial separating systems.

[12] Advantageously, the retractable nature of the fingers circumvents problems of straw wrapping around the rotors which otherwise would reduce the efficiency of the system and ultimately increase the risk of downtime whilst the operators clears wrapped straw.

[13] Each separating rotor is provided with a concave grate on the underside to allow separated grain to pass to the grain cleaning system. The construction of the concave grates may be similar or identical to that of the concave grates disposed under the threshing cylinders. Advantageously, this commonality of parts reduces the number of different components required during assembly and reduces manufacturing costs.

[14] In a preferred embodiment of the invention the separating system comprises three transverse separating rotors with retractable fingers, the separating rotors being positioned one behind the other to convey the crop stream rearwardly. Although a separating system having two, four or five separating rotors is conceivable, it has been found that a system with three rotors offers a favourable balance of separating capacity and straw quality.

[15] Each separating rotor preferably comprises a rotor core mounted for rotation around a first transverse axis, and a finger support shaft aligned along a second transverse axis inside the rotor core and offset below the first transverse axis, wherein each of the plurality of fingers is radially mounted at an inner end thereof for rotation around the finger support shaft and is siideably supported within a respective hole provided in a wall of the rotor core. The offset between the first and second axes provides a cam-style mechanism which dictates the extent and circumferential profile of the finger extension relative to the rotor movement.

[16] In another preferred embodiment the combine further comprises a rear elevator for conveying the crop residue from the separating system rearwardly to outlet means which dispenses the crop residue on the ground. The outlet means may comprise spreading and/or chopping apparatus to dispense the straw on the ground as required.

[17] The threshing apparatus preferably comprises a rotating transverse threshing cylinder having a plurality of threshing bars secured thereto, the threshing bars serving to engage and thresh the cut crop stream against a threshing concave.

[18] Further advantages of the invention will become apparent from reading the following description of a specific embodiment with reference to the appended drawings in which:

Figure 1 is a side elevation view of a combine harvester in accordance with an embodiment of the invention and showing a vertical section through the processing apparatus;

Figure 2 is a perspective view of a separating rotor in accordance with the invention; Figure 3 is an end view of the separating rotor of Figure 2;

Figure 4 is a sectional view of the separating rotor of Figure 2 taken along the line 4-

4 shown in Figure 5; and,

Figure 5 is a sectional view of the separating rotor of Figure 2 taken along the line 5-

5 shown in Figure 3.

[19] From reading the following description it should be understood that the terms 'longitudinal' and 'transverse' are made in relation to the combine harvester's normal direction of travel. In other words, the term 'longitudinal' equates to the fore and aft direction, whereas the term 'transverse' equates to the crosswise direction, or left and right. Furthermore, the terms 'axial* and 'radial' are made in relation to a rotating body such as a shaft or rotor wherein axial relates to a direction along the rotation axis and radial equates to a direction perpendicular to the rotation axis.

[20] With reference to Figure 1 , a self-propelled combine harvester 10 comprises a header 12 which cuts and gathers a strip of crop as the combine harvester 10 is driven across a crop field. Crops cut by the combine 10 may include cereals, protein crops and oilseed rape.

[21] An elevator section 14 conveys the cut crop stream from the header 12 into a central processing apparatus designated generally at 16. The processing apparatus 16 includes threshing apparatus 17, a separating system 18 and a grain cleaning system 19, each of which will be described in more detail below. Clean grain separated from the crop stream is collected in a storage tank 20 which is periodically emptied into a trailer (not shown) via an unloading auger 21. Residue material remaining from the crop stream such as straw and chaff is ejected from the rear of the machine represented by arrow 22. For completeness the combine 10 includes a driver's cab 24.

[22] Turning to the details of the crop processing apparatus 16, the crop stream passes from the elevator 14 into the threshing apparatus 17 which serves to thresh grain or seed from the plants which make up the crop stream. The threshing apparatus includes a threshing cylinder 25 which rotates in a counter clockwise direction as seen in Figure 1 around a transverse axis 26. As in known combines the crop stream is threshed between the threshing cylinder 25 and a first concaved grate 27. Grain and chaff separated in this process falls through the first concaved grate 27 onto an underlying thresher pan 28 forming a primary grain/chaff stream. The first concaved grate therefore separates a percentage of the grain from the crop stream.

[23] The threshing apparatus further includes a transfer beater 30 and a feed beater 31 aligned transversely behind the threshing cylinder 25. The residue straw is conveyed rearwardly from the threshing cylinder 25 sequentially onto the transfer beater 30 and then the feed beater 31. Each of the transfer beater 30 and feed beater 31 have a respective concave grate 32, 33 disposed underneath to allow threshed grain to pass through to the underlying thresher pan 28 and thus separate the grain from the crop stream.

[24] The feed beater 31 rotates counter clockwise as viewed in Figure 1 and conveys the crop stream on the underside thereof in a rearward direction into the separating system 18. The separating system comprises three transverse separating rotors 41 , 42, 43 each with retractable fingers, the separating rotors being positioned one behind the other to convey the crop stream rearwardly. Each of the three rotors has associated therewith a respective concave grate 44, 45, 46 which allow separated grain, tailings and chaff to pass down to an underlying separator pan 47 forming a secondary grain/chaff stream. The separator pan 47 oscillates so as to convey the secondary grain/chaff stream forwardly to combine with the primary grain/chaff stream on the thresher pan 28.

[25] The residue straw is ejected from the separating system 18 at the rear by the third separating rotor 43. The straw is conveyed to the rear of combine 10 by an inclined elevator 50 which comprises a continuous belt 51 supported on two rollers 52, 53. The straw falls from the rear edge of the elevator 50 and out of the combine 10 via a spreading beater 60 which distributes the straw on the ground for subsequent incorporation.

[26] Grain, tailings and chaff collected by the threshing pan 28 are conveyed into the grain cleaning system 19 (often termed 'cleaning shoe') which employs a series of sieves and an airflow to clean the grain in a known manner.

[27] The present invention relates to the separating system 18. Each of the three separating rotors 41 , 42, 43 are similar in construction. First separating rotor 41 is illustrated in more detail in Figures 2-5. However, it will be appreciated that the following description can be applied to the second and third rotors 42, 43 also.

[28] With reference to Figures 2 to 5, separating rotor 41 comprises a cylindrical rotor core (or wall) 62 with two end walls 63. The rotor core 62 is mounted transversely within the combine 10 for rotation around a first axis X which is aligned centrally along the axis of the cylinder. Each circular end wall 63 has a centrally aligned bearing 64 which is secured thereto by bolts 65.

[29] Each end bearing 64 is disposed on a respective stub shaft 66, 67. A circular finger support shaft 68 is located inside the rotor core 62 and extends between the two stub shafts 66, 67, offset therefrom by offset members 69.

[30] At one end of the rotor 41 (left-hand side as viewed in Figure 5) a drive shaft 80 is secured to the end wall 63 by bolts 81. The drive shaft includes an integral dome 82 which provides a seal for bearing 64 and stub shaft 67 to prevent the ingress of dust and dirt. [31] Stub shaft 66 and drive shaft 80 are mounted inside the frame (not shown) of the combine 10 to support the rotor 41. Stub shaft 66 is fixed with respect to the combine frame and so the finger support shaft 68 and both stub shafts 66, 67 do not rotate with the separating rotor core 62. Drive shaft 80 is provided with a belt and pulley drive mechanism (not shown) on the outside of the combine frame to deliver a driving force to rotate rotor 41.

[32] A plurality of retractable fingers 70 are mounted at one end thereof to the finger support shaft 68. Each finger 70 is siideably supported within a respective hole provided in the rotor wall 62. In the embodiment shown, the fingers 70 are distributed in three circumferentially-spaced lines extending along the length of the rotor 41. However, it should be appreciated that the positioning of the fingers around the rotor may vary and is not limited by the means employed to mount the fingers 70.

[33] Best viewed in Figure 4, each finger 70 is supported on shaft 68 by a clamp 72 which rotates on shaft 68. A respective plastic bush 74 is provided at each hole to allow the finger 70 to slide radially with respect to the rotor core 62 without causing significant wear thereto.

[34] From viewing the construction of the rotor 41 , it should be appreciated that the fingers 70 are caused to radially extend and retract as the rotor rotates with respect to the combine frame and, more importantly, to the concave grate 44. The finger support shaft 68 is offset below the rotor axis X so that the fingers 70 are at their greatest extension when positioned at the bottom of the rotation and at their least extension when at the top.

[35] Advantageously, the provision of retractable fingers improves the rearward conveyance of the crop stream and reduces the risk of the material feeding back around the rotors. In turn, this makes the use of transverse rotors a viable alternative to axial separating rotors and straw walker systems.

Claims

1. A combine harvester comprising threshing apparatus, a separating system and a grain cleaning system, the threshing apparatus and separating system arranged in series to sequentially receive and process a cut crop stream, wherein grain separated from the crop stream falls through respective concave grates in the threshing apparatus and separating system, said grain being conveyed to the cleaning system, the separating system comprising a plurality of transverse separating rotors which rotate in the same direction as one another, each separating rotor comprising a plurality of retractable fingers which retract into the rotor when at the top of the rotor and extend radially outward when at the bottom of the rotor so as to convey the crop stream under the rotors and eject crop residue from the rear of the separating system.

2. A combine harvester according to Claim 1 , wherein the separating system comprises three transverse separating rotors with retractable fingers, the separating rotors being positioned one behind the other to convey the crop stream rearwardly.

3. A combine harvester according to Claim 1 or 2, wherein each separating rotor comprises a rotor core mounted for rotation around a first transverse axis, and a finger support shaft aligned along a second transverse axis inside the rotor core and offset below the first transverse axis, wherein each of the plurality of fingers is radially mounted at an inner end thereof for rotation around the finger support shaft and is slideably supported within a respective hole provided in a wall of the rotor core.

4. A combine harvester according to any preceding claim, further comprising a rear elevator for conveying the crop residue from the separating system rearwardly to outlet means which dispenses the crop residue on the ground.

5. A combine harvester according to any preceding claim, wherein the threshing apparatus comprises a rotating transverse threshing cylinder having a plurality of threshing bars secured thereto, the threshing bars serving to engage and thresh the cut crop stream against a threshing concave.