WO1992005687A1

WO1992005687A1 - A device for spreading chaff and husks from a combine harvester

Info

Publication number: WO1992005687A1
Application number: PCT/SE1991/000659
Authority: WO
Inventors: Peter Nilsson
Original assignee: Rekordverken Sweden Ab
Priority date: 1990-10-02
Filing date: 1991-10-02
Publication date: 1992-04-16
Also published as: SE466880B; SE9003121A; AU8642691A; SE9003121D0

Abstract

A device for spreading chaff (16) and husks (17) from a combine harvester across substantially the entire harvester cutting width. The chaff and the husks are carried in an exiting stream of air which is directed essentially rearwardly as seen in the direction of travel (A) of the harvester, from a screening means (18) designed to separate the chaff (16) from the corn (10), to a downwardly directed outlet (21) from said screening means. In the area of the screening means outlet (21) there is a deflector (23) to deflect the exiting stream of air (22) in which the chaff (16) and the husks (17) are carried, in a direction laterally and downwardly as seen in the direction of travel (A), towards the ground, in order to distribute and spread the chaff and husks across the entire cutting width.

Description

A device for spreading chaff and husks from a combine harvester.

The subject invention concerns a device for spreading chaff and husks from a combine harvester across sub- stantially the entire cutting width of the harvester, said harvester comprising a screening means to separate the chaff from the grain, as well as a device generating a discharge stream of air which is essentially rearwardly directed as seen in the direction of travel of the har- vester, said stream of air serving to direct the chaff and the husks away from the screening means to an essentially downwardly directed outlet from said means.

Conventional combine harvesters are fitted with a pick-up reel including a cutting table the width of which greatly exceeds that of the harvester proper. In harvesting straw feed crops, the consequence hereof will be deposition, after threshing, of the chaff and husks on the ground, i.e. the field, in a comparatively narrow string the width of which essentially agrees with that of the screening means. Today, it is common practice to chop up or cut the straw after threshing by means of a chopper and to spread the chopped material over an area having a width essentially corresponding to that of the cutting table and to later plough in the chopped material into the soil. Consequently, the field will exhibit string- shaped areas wherein the contents of chaff and husks exceed those of adjoining areas the chaff and husk con¬ tents of which are practically nul. Such uneven distri¬ bution changes the conditions of growth and as a rule, growth is hampered by too large quantities of undecayed straw, chaff and husks.

The purpose of the subject invention is to provide a device designed to spread the chaff and husks over sub¬ stantially the entire cutting width of the harvester, thus ensuring a continuous and even distribution across the field. The arrangement must not affect the feed of unchopped straw to the chopper, nor negatively affect the separation of the chaff from the grain. In addition, also when the straw is to be deposited in the form of strands, for example, it must still be possible to spread the chaff and husks over the entire cutting width of the harvester without, however, causing spreading of the straw or inter¬ ference with the straw feed.

These and other purposes in accordance with the invention are achieved by the provision of a deflector in the area of the screening means outlet to deflect the exiting stream of air in which the chaff and the husks are carried, towards the ground in a lateral and downwards direction with respect to the direction of advancement of the harvester, as well as to distribute and spread the chaff and husks on the ground across the cutting width, said deflector being in the shape of a body formed with deflecting surfaces, said surfaces extending obliquely with respect to the essentially rearwardly directed, exiting stream of air for the purpose of deflecting said stream of air laterally and downwardly, said body having a size which is so much smaller than the downwardly directed outlet of the screening means and which is so positioned with respect to the latter that the pressure drop of the exiting stream of air across the body is minimal, a gap being defined between the upper delimi- tation face of the body and an upper partition wall positioned opposite the downwardly directed outlet of the screening means, said gap allowing passage there¬ through of part of the exiting stream of air.

The invention will be described in closer detail in the following with reference to the accompanying drawings, wherein

Fig. 1 is a schematical and partly broken lateral view of the combine harvester fitted with the device in accordance with the invention, Fig. 2 is a perspective view as seen obliquely from behind and below, of the part of the combine harvester in accordancae with Fig. 1 where the device in accordance with the invention is positioned,

Figs. 3a-c are perspective views as seen obliquely from behind of some embodiments of a deflector incorp¬ orated in the device in accordance with the invention, Figs. 4A, 5A and 6A illustrate the rear part of the harvester in accordance with Fig. 1 in schematic and partly broken views, to illustrate alternative positions of the deflector, and

Figs. 4B, 5B and 6B show views as seen in the direction of respectively arrows B, C and D in Figs. 4A, 5A and 6A.

The combine harvester designated generally by reference 1 in the drawing figures is of rather convent¬ ional configuration with the exception of the device in accordance with the invention, generally designated by reference 2. It has a pick-up reel 3 including a cutting table 4 having a width considerably exceeding that of the harvester 1 proper, for instance double that width. The cut straw-feed crop 5 is transported via a transverse conveyor 6 and a longitudinal conveyor 7 up to a thresher 8, where the straw 9 is separated from the grain 10. The straw 9 is furthered via an oscillating conveyor 11 up to an impact chopper 12 positioned at the rear end of the harvester as seen in the direction of travel of the latter. The chopper 12 chops up^' or cuts the straw 9 into smaller pieces and a spreader, not illustrated in detail and positioned adjacent an outlet 14, spreads the chopped straw pieces 13 onto the ground, i.e. the field 15, over an area the width of which essentially corresponds to the width of the cutting table 4.

The grain 10 from the thresher as well as the chaff 16 and husks 17 are feed to a screening device 18 com¬ prising a number of screens 19 and a screening fan 20. The chaff 16 and the husks 17 are separated from the heavier grain 10 when passing through the screens 19, the chaff and the husks being blown away in the direc¬ tion towards an essentially downwardly directed outlet 21 from the screening device 18, with the aid of the generally rearwardly directed stream of air 22 which is Generated ia~^τ the screening fan 20.

A deflector, generally designated by reference 23, is positioned in the area of the outlet 21 of the screening device 18. The purpose of the deflector is to deflect the exiting stream of air 22 carrying the chaff 16 and the husks 17 laterally and downwardly as seen in the direction of travel A, towards the ground 15, and to distribute and spread the chaff and the husks onto the ground across the entire cutting width of the harvester 1, as illustrated in Figs. 1 and 2.

Downstream of the deflector 23 as seen in the direc¬ tion of flow of the exiting stream of air 22, there is provided a unit, designated generally be reference 24, which is designed to impart a further laterally extended distributing movement to the stream of air for more efficient spreading of the chaff 16 and the husks 17 over the cutting width. Generally speaking, the deflector 23 is shaped as a body 25 comprising deflecting surfaces 26 which are oblique with respect to the rearwardly directed exiting stream of air 22 so as to deflect said stream of air laterally and downwardly. Owing to this arrangement, the spatial extent of the body 25 becomes much smaller than that of the down¬ wardly directed outlet 21 of the screening device 18 and the body 25 will be assume such a relative position with respect to said outlet that the pressure drop of the exiting stream of air 22 across the body 25 becomes minimal, in addition to which a gap 29 will be defined intermediate the upper delimitation face 27 of the body and an upper partition wall 28 positioned opposite the downwardly directed outlet 21 of the screening device 18, which gap 29 allows passage therethrough of part of the exiting stream of air. In accordance with the embodiments illustrated in the drawings, the body 25 is in the form of a bent plate of a suitable, preferably rigid material, such as sheet metal. When required, the sheet metal element may be coated on at least its oblique surfaces 26 with a vibration- dampening and/or sound absorbing substance. Obviously, it is quite possible to manufacture the entire plate 25 from a vibration-dampening and/or sound absorbing material.

In accordance with the embodiment illustrated in Figs. 1, 2 and 3, the plate 25 has a generally V-shaped profile whereas in accordance with the embodiment of Fig. 3b, the profile configuration is a combination of a V-shape and a U-shape and the embodiment in accordance with Fig. 3c has a U-shaped profile configuration with the legs of the U-shape tapering outwards. Other profile configurations are, of course, possible,^' the condition being that the stream of air 22, carrying the chaff 16 and the husks 17, is deflected laterally and downwards. In all embodiments according to Figs. 1-3 the plate 25 has a cross-section which increases, preferably progressively, in the direction of travel A from its front point 30 towards the rear edge 31. As appears from Figs. 1 and 2, the plate 25 is freely suspended in the chassis of the combine harvester 1 along the upper plate edges 32, preferably in stays 33 or similar means attached to the harvester chassis.

The unit 24 described above, designed to impart the further laterally extended distributing motion to the exiting stream of air 22 downstream of the deflector 23 in the form of a plate 25, comprises a fan 34 which is mounted on the harvester at a level below the plate 25, cf. Figs. 1 and 2. In accordance with the embodiment illustrated, the fan 34 is a cross-flow fan having an essentially horizontal outlet 35, the width of which essentially agrees with that of the outlet 21 of the screening device 18. The outlet 35 houses spreader means 36 in the form of configured guide plates serving to direct the outlet air 37 from the fan 34 towards the exiting stream of air carrying the chaff 16 and the husks 17. Owing to this arrangement, the exiting stream of air is given the further laterally extended distribut¬ ing motion, ensuring that the chaff and the husks are spread onto the ground 15 across entire the cutting breadth ahead of the chopped straw 13, as seen in the direction of travel A.

Alternatively, the unit 24 above could include, instead of the cross-flow fan 34, one or several rotor- type spreaders which, like the first-mentioned spreaders, are positioned in the area below the plate 25 and which may be arranged to rotate about rotational shafts which are substantially vertical or extend obliquely with respect to the vertical. When the rotational spreader or spreaders is (are) hit by the stream of air 22 carrying the chaff 16 and the husks 17, said stream of air is given the above distributing motion having a further lateral extent.

Figs. 4-6 illustrate some other possible alterna¬ tive positions of the deflector 23 described in the aforegoing. In accordance with Figs. 4A and 4B the deflector 23 assumes an essential vertical position in the are of the outlet 21 and it is preferably mounted on a guide plate 38 which is incorporated in the chopper 12. The deflector 23 extends downwards from the outlet 21 and terminates essentialy opposite the unit 24.

In accordance with the alternative illustrated in Figs 5A and 5B, the deflector 23 is positioned obliquely downwardly and rearwardly in said area and preferably it is mounted on a crosswise stay 39 arranged on the hood of the harvester 1. Also in this case the deflector 23 extends downwards from the outlet to the level flush with the unit 24. . Finally, in accordance with the alternative shown in Figs. 6A and 6B, the deflector 23 is mounted on the lower face of the chopper 12 in the area of the outlet 21 and level with or opposite the unit 24.

The invention should not be regarded as restricted to the embodiments illustrated and described herein but a number of modifications are possible within the scope of the appended claims.

Claims

CLAIMS 1. A device for spreading chaff (16) and husks (17) from a combine harvester (1) across substantially the entire cutting width of the harvester, said harvester (1) comprising a screening means (18) to separate the chaff (16) from the grain (10), as well as a device (20) generating a discharge stream of air (22) which is essentially rearwardly direction as seen in the direction of travel (A) of the harvester (1), said stream of air (22) serving to direct the chaff (16) and the husks (17) away from the screening means (18) to an essentially downwardly directed outlet (21) from said means, c h a r a c t e r i z e d by a deflector (23) which is positioned in the area of the outlet (21) of the screening means (18) to deflect the exiting stream of air (22) in which the chaff (16) and the husks (17) are carried, towards the ground (15) in a lateral and downwards direction with respect to the direction of advancement (A) of the harvester, as well as to distribute and spread the chaff and the husks on the ground across the cutting width, said deflector (23) being the shape of a body (25) formed with deflecting surfaces (26), said surfaces extending obliquely with respect to the essentially rearwardly directed, exiting stream of air (22) for the purpose of deflecting said stream of air laterally and downwardly, said body (25) having size which is so much smaller than the downwardly directed outlet (21) of the screening means (18) and which is so positioned with respect to the latter that the pressure drop of the exiting stream of air (22) across the body (25) is minimal, a gap (29) being defined between the upper delimitation face (27) of the body and an upper partition wall (28) positioned opposite the downwardly directed outlet (21) of the screening means (18), said gap allowing passage therethrough of part of the exiting stream of air.

2. A device as claimed in claim 1, c h a r a c ¬ t e r i z e d in that the body is in the form of a bent plate (25) of an essentially V-shaped or U-shaped profile configuration with the legs of the U being straight or inclined, and in that the plate cross-section increases as seen in the direction of travel (A), from the front point (30) of the plate towards the rear edge (31) thereof.

3. A device as claimed in claim 2, c h a r a c - t e r i z e d in that the plate (25) is freely suspended in the chassis of the harvester (1) along its upper edges (32).