GB2171285A - Threshing device for combine harvesters - Google Patents

Abstract

A combine harvester includes a cutter assembly, threshing means (11,12) and a fan (17) for delivering threshed grain to a storage chamber. A first thresher (11) includes a concave (13) and a rotatable shaft (16) carrying swing hammers or chains. When the shaft (16) is rotated, the swing hammers or chains draw the cut crop into the thresher (11) and the crop is threshed against the concave (13). Any grain remaining with the waste is threshed in the second thresher (12) similar to the thresher (11) but upside down. <IMAGE>

Description

SPECIFICATION Improvements in combine harvesters The invention relates to combine harvesters.

Combine harvesters have been in existence for many years, and essentially consist of a cutter assembly at the frontfor cutting wheat, corn or other material to be havested, a conveyor or the like to move the cut crop to a thresher, and a conveyor for transporting the grain or other threshed crop to a storage hopper. Combine harvesters are generally self propelled and store the grain or the like in the hopper until able to discharge it into an appropriate container or vehicle.

In known combine harvesters, the thresher has a threshing drum with about eight serrated bars arranged longitudinally about the drum's axis.

These bars breakthecrop against a part cylindrical grid of longidutinal bars and circumferential wires known In the art as a "concave". The term concave will be used hereafter in this specification, and it will be appreciated that its construction may differ from that described; however, the essential feature of a concave is that it allows grain, corn or the like (the term "grain" will hereinafter be used to refer to all threshed crop) to pass through it, while preventing straw or other unwanted matter from passing through it.

Some grain bounces off the concave and in order to collect this stray grain, combine harvesters include a shaker or shakers behind the thresher to which the straw from the thresher is fed, the shakers collecting grain which is passed out of the thresher with the straw. Such shakers are generally inefficient on combine harvesters because they cannot be kept level, as the harvester of necessity travels over undulating ground.

One problem which occurs with conventional combine harvesters is that, while there is no real constraint on the width of the cutter assembly, the threshing drum is difficult to balance when longer than about 5ft, so is normally significantly narrower that the cutter assembly, typically in the ratio 4:1.

This tends to overload the thresher and cause inefficient threshing. "Full width threshing", that is a threshing drum of substantially the sme width as the cutter assembly, has been proposed, but found to be impractical because of the difficulties in balancing the threshing drum.

According to the invention there is provided a combine harvester comprising a cutter assembly, means for threshing cut crop, storage means and means for transporting grain (as hereinbefore defined) from the threshing means to the storage means, the threshing means comprising a concave (as hereinbefore defined), a rotatable shaft arranged coaxially with the concave, a plurality of swingable members mounted on the shaft such that rotation of the shaft swings said swingable members to draw in the cut crop for threshing against the concave.

The concave may lie above the shaft.

The swingable members may be swing hammers or chains.

The transporting means may comprise a fan.

The width of the threshing means is preferably at least half the width of the cutter assembly; indeed the width of the threshing means is preferably substantially the same as the width of the cutter assembly.

The combine harvester may include a second threshing means for threshing material other than the separated grain exahusted from the first threshing means.

The second threshing means may include a concave (as hereinbefore defined), a rotatable shaft and a plurality of swingable members mounted on the shaft such that rotation of the shaft swings said swingable members outwardly.

The concave of the second threshing means may lie below the associated shaft.

The shafts of the first and second threshing means may rotate in different directions.

By way of example, one embodiment of a combine harvester according to the invention will now be described with reference to the accompanying drawings, in which: Figure ? is a perspective, partly cutaway view of part of a combine harvester according to the invention; and Figure 2 is a diagrammatic side view of the apparatus shown in Figure 1 to illustrate flow of material.

Figures 1 and 2 show a part of a combine harvester. The other parts of the combine harvester will not be described in detail since they are essentially conventional in nature. The part shown in Figures 1 and 2 is the threshing part of the combine harvester. In advance of the threshing part is a cutter assembly which consists of a cutter bar and a rotating cage for bending the uncut crop towards the cutter bar. Whereas in known combine harvesters, a conveyor is necessary for conveying the cut crop from the cutter assembly to the thresher, there is no need for such a conveyor in the embodiment of the invention herein described. The action of swing hammers or chains which will be described hereinafter draws the cut crop into the thresher without need for specific conveying means. Swing hammers would be preferable to chains.

Downstream of the thresher, material is delivered to a storage hopper or the like and again, the storage hopper is conventional and will not be described.

The combine harvester is self propelled conventionally and a skilled man needs no description of suitable motive means.

The description will thus concentrate on the threshing apparatus shown in Figures 1 and 2.

In a main casing 10 of the combine harvester is arranged a main thresher generally indicated at 11 and a second, auxilliary thresher generally indicated at 12.

The main thresher 11 includes a concave 13 (shown partly cut away) consisting of longitudinal bars 14 and circumferential wires 15, the spacing of the wires 15 being at intervals of approximately 4 cm.

Within the concave extends an elongate shaft 16 mounted on bearings and rotated, in use, by the combine harvester power source (not shown). The shaft 16 carries regularly spaced swing hammers or chains, a sutiable number being 12 along its length although it will be appreciated that other numbers may be used, rotation of the shaft 16 in operation causing the swing hammers or chains to swing outwardly. The chains or swing hammers are conventional in nature and are not shown in the drawings to avoid unnecessary complication.

On the downstream side of the concave 13 is arranged a delivery fan 17 which feeds threshed grain to a delivery duct 18.

In use, rotation of the shaft 16 and hence the swing hammers or chains causes the cut crop to be drawn into the thresher 11 through inlet ducts 19 without the need for positive conveying of the crop from the cutter assembly. The crop is threshed against the concave 13 and the majority of grain (as hereinbefore defined) passes through the concave 13 and is drawn through to the delivery duct 18 by the delivery fan 17.

Waste material leaves the main thresher via duct 20 and heavier material including grain caught up with waste falls into the second, auxiliary thresher 12. The auxiliary thresher 12 is similar in construction to the main thresher 11, but upside down. It will be appreciated, however,thatthere is no absolute need for the auxiliary thresher 12 to be upside down.

The auxiliary thresher 12 has a concave 21 and a rotatable shaft 22 carrying swing hammers or chains. In use, the auxiliary thresher 12 carries out a second threshing operation to separate such grain as is caught up with waste from the main thresher 11. Grain passing through the auxiliary concave 21 is routed to the hopper by suitable conveying means (not shown) and waste from the auxiliary thresher is passed out along duct 23.

Ducts 20 and 23 lead out of the combine harvester.

The threshers 11 and 12 extend across the width of the combine harvester and are substantially the same width as the cutter assembly. This means that there is an even flow of cut crop to the threshers and no bunching as is the case with conventional combine harvesters. This arrangement means that a combine harvester according to the invention could travel significantly faster than a conventional combine harvester and also that waste material is deposited evenly behind the combine harvester.

It is a distinct advantage that the swing hammers or chains are able to draw cut material into the threshers without the need for positive conveyors as has hitherto been the case.

This embodiment of a combine harvester according to the invention could be significantly cheaper to produce than the combine harvesters including a threshing drum with beater bars, as the power requirement is less, and less ancillary apparatus (conveyors, for example) are necessary.

There is a disadvantage that the combine harvester is of greater width, but the cutter assembly and thresher could be dismantlable if width is a problem (the cutter assemblies of known combine harvester are commonly dismantlable), or the combine harvester could be movable sideways (because of less ancillary apparatus such as conveyors, the combine harvester of this embodiment of the inventin would be much shorterthan a conventional combine harvester). For example, a further set of wheels, or wheels steerable through 90 could be provided to allow sideways movement.

Claims (12)

1. A combine harvester comprising a cutter assembly, means for threshing cut crop, storage means and meansfortransporting grain (as hereinbefore defined) from the threshing means to the storage means, the threshing means comprising a concave (as herein before defined), a rotatable shaft arranged coaxially with the concave, a plurality of swingable members mounted on the shaft such that rotation of the shaft swings said swingable members outwardly, and means for rotating the shaft, rotation of the shaft, in use, causing the swingable members to draw in the cut crop forthreshing against the concave.

2. A combine harvester as claimed in Claim 1 wherein the concave lies above the shaft.

3. A combine harvester as claimed in Claim 1 or Claim 3 wherein the swingable members are swing hammers.

4. A combine harvester as claimed in Claim 1 or Claim 2 wherein the swingable members are chains.

5. A combine harvester as claimed in any preceding Claim wherein the transporting means comprises a fan.

6. A combine harvester as claimed in any preceding Claim wherein the width of the threshing means is at least half of the width of the cutter assembly.

7. A combine harvester as claimed in Claim 6 wherein the width of the threshing means is sub- stantially the same as the width of the cutter assembly.

8. A combine harvester as claimed in any preceding Claim including a second threshing means for threshing material other than the separated grain exahusted from the first threshing means.

9. A combine harvester as claimed in Claim 8 wherein the second threshing means includes a concave (as hereinbefore defined), a rotatable shaft and a plurality of swingable members mounted on the shaft such that rotation of the shaft swings said swingable members outwardly.

10. A combine harvester as claimed in Claim 8 or Claim 9 wherein the concave of the second threshing means lies below the associated shaft.

11. A combine harvester as claimed in any one of Claims 8 to 10 wherein the shafts of the first and second threshing means rotate in different directions.

12. A combine harvester substantially as hereinbefore described with reference to and as shown in the accompanying drawings.