AU683397B2 - Harvester concave - Google Patents

Description

Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

C

Name of Applicant: Actual Inventor: Address for Service: HARVESTAIRE PTY LTD Dean Raymond BROOKS KEN MADDERN PATENT ATTORNEY, Floor, 150 Grenfell Street, Adelaide, South Australia, 5000 Invention Title: "Harvester Concave" Details of Associated Provisional Application No: PM 8553 dated 29th September, 1994 The following statement is a full description of this invention, including the best method of performing it known to the applicant.

-1- This invention relates to a harvester concave of the type which is used on a grain harvester for threshing grain or seed kernels, to separate stalks, husks and eefg1rom the kernels.

BACKGROUND OF THE INVENTION For many years the general principle of threshing grain or seed in commercial harvesting machinery has not substantially changed. In early machines, the threshing of the cut crop was achieved by the delivery of the cut crop "face on", or tangentially, at 900 to a cross ways or width mounted rotating cylinder, on which forged steel bars with angled teeth were attached. The rotating cylinder forced the cut crop material to go in between these bars and other stationary bars which were part of a non-rotating grate or concave, which S:"I was mounted adjacent to and usually below the rotating cylinder. This action retarded the material and beat it to achieve a primary separation of the stalks/husks/ears from the useable grain or seeds. Further separation occurred downstream of the concave, the grain/seeds usually being passed over straw walkers and sieves which together with impelled air then further separated the grain from the lighter chaff and other materials.

**In recent years there has been a commercial trend away from the above described "face on" conventional design to a rotary or axial flow type of system.

20 This design of harvester differs from the design of the more conventional type of system described above, by having one or more threshing cylinders mounted lengthwise in the machine, that is with axes of rotation extending along the harvester's length and not across the width, and the crop is fed into a cylinder and is conveyed in a spiral motion between the rotating cylinder bars and the non-rotating concave bars along the length of the cylinder, which allows a longer threshing area, in order to better thresh the grain from the husks etc and also to separate it further. In some instances, the grain and other material is then passed over sieves in the usual fashion which together with an air draft 2 finally cleans the grain before it is fed into the harvester's bulk storage bin, This cleaning stage can at least be reduced compared with the older tangential threshing, or sometimes be dispensed with, since the separation can all be achieved within the rotor housing, usually downstream of the concave assembly.

Sometimes this axial flow principle involves a threshing cylinder mounted transversely across the width of the machine. The significant difference between any machine incorporating the axial flow principle and early art is that in the axial flow principle the material enters at one end of the cylinder and is transported along its length rotating in a spiral fashion, commonly rotating between 4 and 11 times along its length during the threshing and separation process. An early art arrangement directs material to enter along the full length of the side of the cylinder but the material rotates only 1800 or less around the circumference of the cylinder before being ejected and proceeding to further separation on straw walkers and sieves.

•The American company J I Case, of 700 State Street, Racine, Wi produces axial flow combines, models 1620, 1640, 1660 and 1680, which are typical of combines to which this invention is applicable.

Current technology in the above rotary or axial flow designs embraces *20 grates or concaves which have steel bars placed in and parallel to the axis of the rotating cylinder, that is lengthwise. Because these concave bars are mounted lengthwise and the grain and material which need to be separated are being propelled spirally through the machine, the material contacts the concave but not in a "face on" attitude and so tends to easily slip between the bars and aggressive threshing is hard to achieve, without speeding up the rotating cylinder. The closest orior art known to the Applicant herein is disclosed in Australian Specification 51950/79 (538471), White Motor Corporation of Canada.

BRIEF SUMMARY OF THE INVENTION The main object of this invention therefore is to provide an arrangement where more effective threshing can be achieved than with the known concaves, when associated with axial flow threshing cylinders, and in an embodiment of the invention, a concave is provided with bars extending longitudinally and circumferentially thereby forming an approximately helical path which has an opposite spiral inclination from the spiral inclination of the path of travel of the heads to be threshed.

With this invention, therefore, the heads to be threshed pass across the fixed threshing bars, in a direction which approaches right angles to the direction of the fixed bars. This "face on" threshing will be found to be more efficient than the threshing of heads which impinge against bars which are only inclined to the direction of travel. The spaced grid wires which cross the thresher concave bars are then in line with the threshed material, which will pass through the concave with a minimum of obstruction.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment is described hereunder with reference to and is illustrated in the accompanying drawings, in which Fig 1 is a diagrammatic isometric view showing (in part section) an axial flow thresher assembly; Fig 2 is a perspective diagrammatic view of the concave according to this invention; and Fig 3 is a fragmentary perspective view illustrating the orientation of the fixed thresher bars and straw separating wires, with respect to crop flow through the thresher assembly.

Fig 1 illustrates an axial flow thresher assembly 10 having an outer fixed rotor housing 11 of cylindrical shape, containing a rotor 12 carrying on it two sets of thresher bars 13 (which include bars extending both axially and helically), the rotor 12 being secured to a central driven shaft 14, journalled in bearings 15. Shaft 14 has an impeller 16 at the upstream end of the assembly which impels crop material including grain heads (for example) into the annular space between the rotor 12 and the rotor housing 11. Rotor 12 extends only part way along the rotor housing 11. The description heretofore is well known in prior art, and forms no part of this invention.

The interior surface 20 of the housing 11 is provided with an inwardly directed spiral vane 21 which, as drawn, can extend beyond the downstream end of rotor 12, and assist in guiding a crop to continue its passage in a spiral, or helical, direction. In spacing the concave from surface 20, the vanes provide a free flow path for threshed material.

This invention is best illustrated in Figs 2 and 3, and is concerned mainly with the threshing bars 22 of concave 23, and the separation grid wires As illustrated in Fig 1, the blades 21 are arranged in a right-hand direction of spiral inclination, that is, they assist in imparting a clockwise helical path of movement to the cut crop, when viewed from the upstream end. In all prior art otherwise known to the Applicant, the stationary thresher bars of the concave have extended in an axial direction, so the crop was impacted against those bars at an acute angle. In this embodiment, the slope of the thresher bars 20 22 approximates a left-hand spiral, thereby forming a counter-clockwise helical path, so that the path of travel of the crop is generally normal to the fixed threshing bars 22, and the crop impacts at more nearly 900 against them.

Furthermore, the separation wires 25 which extend behind or through the bars 22 are then placed substantially parallel to the direction of the righthand swirl of the heads being threshed and are therefore more in line with the flow of grain as it is being beaten out of the head, so that the bulk grain can pass through the wires more easily and so aid quicker and better threshing with less tendency to crack by being struck a second time by one of the rotating cylinder bars. The "clear" space within housing 11 downstream of rotor 12 functions to efficiently perform further separation of the grain from the chaff, thereby reducing load on straw walkers or sieves. This is a matter of some importance, since speed of reaping is largely curtailed by the rate at which separation can be achieved.

Apart from the concave modifications referred to above, concave 23 is generally similar to known art concaves, having a peripheral frame 28 with circumferentially extending side frame members 29 which are curved to lie within, but spaced from interior surface 20 of the housing 11 by the spiral blades 21, and axially extending end members 30. The sloping threshing bars 23 are apertured to carry the separation grid wires 25 at right angles to the bars 23.

This invention is distinguished from the aforesaid White Motor Corporation patent 538471, firstly in that the latter refers to already threshed material, whereas this invention relates to the threshing process. Secondly, the concave herein is not necessarily the rotor casing, and not necessarily the "upper inner surface" of the casing. It is more likely to be used as illustrated, that is, substantially beneath and to one side of the rotor. Thirdly, the White Motor invention refers to the circumferentially disposed guide vanes at the 20 discharge end. The concave of this invention is associated with the entry end of the thresher.

Claims (6)

1. In an axial flow thresher assembly of a harvester having a rotor with thresher bars and an impeller thereon which impart a helical path of movement to a cut crop and having one direction of spiral inclination, a concave comprising fixed threshing bars co-operable with said rotor thresher bars, the fixed threshing bars sloping to approximate an opposite direction of spiral inclination which is generally normal to said helical path of crop movement.

2. A concave according to claim 1 wherein said concave comprises a peripheral frame having circumferentially extending side members and axially extending upper and lower members, said fixed threshing bars sloping in one direction within said side and end members, and separation grid wires carried by said fixed threshing bars and extending at right angles thereto.

3. An axial flow harvester thresher assembly comprising a 15 rotor with thresher bars on an outer surface, an impeller at one end having o blades which impart both axial and rotational movement to a cut crop thereby imparting a helical path of movement, and a concave comprising fixed threshing bars co-operable with said rotor thresher bars, the fixed threshing bars sloping to approximate an opposite 20 direction of spiral inclination which is generally normal to said helical path of crop movement.

4. An axial flow harvester thresher assembly according to claim 3 further comprising a generally cylindrical rotor casing surrounding said rotor and concave, and a spiral vane extending between an inner surface of said casing and said concave. An axial flow harvester thresher assembly according to claim 4 wherein said spiral vane extends within said housing downstream from said concave.

I

6. A method of threshing a cut crop in an axial flow thresher of a harvester, comprising imparting a helical path of cut crop movement within a rotor casing by driving a rotor drum having an impeller at an upstream end and thresher bars on the drum, threshing said cut crop by impacting said crop against fixed threshing bars of a concave which are substantially normal to said path of crop movement, passing said threshed material between said fixed threshing bars and into a space defined by helical vanes which extend between said rotor casing and said concave, and discharging said threshed material from a downstream end of said rotor casing. DATED this 7th day of August, 1995 15 HARVESTAIRE PTY LTD By its Patent Attorney KEN MADDERN i ABSTRACT An axial flow thresher (10) for us on a grin harv ster.fr threshing grain or seed kernels, to separate stalks, husks and ee@from the kernels, is provided with a rotor housing (11) having inwardly directed blades (21) extending in one direction of spiral inclination, and a concave (23) is provided with fixed threshing bars (22) which extend in an opposite direction of spiral inclination. This results in more direct impact of the crop against the threshing bars (22). S°eeo e-° -o f ef