COMBINE HARVESTER

Abstract: A combine harvester is provided which is built accordingly to the modular concept and which comprises a o. a threshing module (20), a separating module (30) and a cleaning module (40) detachably connected to each other in an operational manner. One or more of said modules is interchangeable with another module (27, 80 / 34, 65, 75, 80 / 50) of a different type.

Description: The present invention relates to harvesting machines such as combine harvesters and more particularly is concerned with combine harvesters built following the modular concept. In known combine harvesters, grain is threshed and separated in a threshing and separating mechanism and the separated grain, together with the impurities, such as chaff, dust, straw particles, and tailings, is fed to a cleaning mechanism for cleaning. Clean grain is collected below the cleaning mechanism and fed to a grain tank for temporary storage. The tailings are separated from the clean grain and impurities for reprocessing. This reprocessing either involves recycling the tailings through the threshing and separating mechanism or treating them in a separate tailings rethreshing means. In the standard commercially available combines, the rotatable threshing cylinder and cooperable concave extend transversely to the direction of movement of the combine. The crop is fed to the concave and passed between the concave and threshing cylinder whereby it is threshed. The straw is discharged rearwardly of the concave onto reciprocating or oscillating straw walkers that extend longitudinally of the combine. Much of the grain contained in the crop material fed to the threshing mechanism is threshed and separated by that mechanism and some of the remainder is separated from the straw whilst the latter is on the straw walkers. Straw walkers have proved to be the capacity-limiting components of the standard combine because, when operating at high capacity rates, much grain is discharged with the straw to the straw walkers which are unable to cope with the required separation, and hence unacceptable grain losses occur. Recent developments in combine harvesters have led to so-called rotary machines wherein both threshing and separating are accomplished in mechanisms comprising rotary components cooperable with respective stationary threshing and separating concaves and grates. In rotary combines the crop material is subjected to a much more aggressive and positive separating action during a relatively prolonged period of time, whereby the efficiency of a rotary combine harvester usually is greater than that of a conventional machine. Several types of rotary combine harvester have appeared on the market and in one such machine a conventional transversely-extending, threshing mechanism having a threshing cylinder and a cooperable concave is combined with a rotary separating mechanism having a rotor of a width greater than that of the threshing mechanism and disposed parallel thereto with its end extending transversely past the respective ends of the threshing mechanism. The rotary separating mechanism operates spirally to convey the crop material received from the threshing mechanism towards each of its end, whilst submitting the crop to a separating action. With such a separating mechanism, the incoming layer of crop material has to be divided in two substantially equal portions, each of which is then spirally conveyed from the centre of the separating mechanism to one or other of its ends. In another, so-called axial-flow-type combine harvester the threshing and separating mechanism extends longitudinally (fore-and-aft) of the machine, parallel to the direction of movement and comprises at least one threshing and separating rotor and co-operable concave. The crop material is fed to the forward end of the threshing mechanism and is formed into a mat which passes generally axially therethrough in a spiral path. In axial flow machines, the crop material is subjected to a threshing and separating action far longer than in a standard machine of comparable size and, therefore, the efficiency of the former is greater than the efficiency of the latter. It has been proven in practice that the conventional combines and the rotary combines both have advantages and disadvantages which influence the end user's buying decision. Accordingly there is a market for both conventional and rotary combines. Turning now to the cleaning apparatus of both conventional and rotary combines, it is readily appreciated that the efficiency of a cleaning system of a combine harvester is greater if threshed crop material is fed thereto in a regular manner and the cleaning air blast is uninterrupted. As a rule, this is achieved only if the combine harvester is in a virtually horizontal position. When the ground is irregular, and particularly when inclined, different things can happen in the cleaning mechanism dependant on a number of factors, such as the direction and extent of the inclination of the combine to the horizontal. When the combine harvester is oriented such that it is inclined to the horizontal transversely in relation to the direction of travel, crop material separated from the straw in the threshing and separating means tends to move to the lower side of the grain pan. This sideward shifting of crop material is continued during its transport along the grain pan, during its transfer from the grain pan to the cleaning sieves, during its movement across the cleaning sieves and during its fall from one sieve to another sieve disposed therebelow. The result of all this is that the higher sides of the sieves are virtually free of crop material while the lower sides thereof are so heavily loaded with crop material that clogging may occur. This in turn results in grain emerging from the combine harvester at the rear instead of passing through the sieves the causing considerable grain losses at the lower side of the sieves. With uneven loading of the sieves, the cleaning air blast is unequally effective, so that cleaning is diminished considerably. Indeed, cleaning air tends to escape through the underloaded sieve sections, thus leaving the overloaded sieve sections with a reduced air blast. One solution to this problem has been given by the provision of an automatically self-leveling cleaning apparatus such as disclosed in GB 2.052.238. Other solutions equally are available on the market. It will be appreciated that farmer's will want such a self-leveling cleaning apparatus only when they have to operate their combine in hilly conditions. Otherwise, the additional cost for such an apparatus is not warranted. All the foregoing means that, to be able to meet all customer requirements, a manufacturer would have to offer a very wide range of combine models which is unprofitable especially in times when the market for combine harvesters is in a downturn and pressure on prices is high. It is the object of the present invention to overcome this and other problems of the prior art. According to the invention, a combine harvester is provided comprising : - a header adapted for receiving crop material from the field; - threshing means for threshing crop material received from the header and separating grain therefrom; - separating means disposed to receive threshed crop material from the threshing means and operable to separate further grain from the crop material which has not previously been separated therefrom by the threshing means; - cleaning means positioned to receive threshed and separated grain from the threshing means and the separating means and operable to separate clean grain from discardable crop material; - grain storage means operable to temporarily store clean grain received from the cleaning means - a power source operatively coupled to the various machine components for driving said machine components; and - an operator's station with controls for enabling the operator to control the harvesting operation; the combine harvester being of a modular design and including at least a threshing module, a separating module and a cleaning module detachably connected to each other in an operational manner; and which is characterised in that at least one module is interchangeable with another module of a different type. A combine harvester embodying the present invention will now be described in greater detail by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic perspective "exploded" view of a combine harvester built according to the modular concept and embodying a first particular combination of specific individual modules, Figure 2 to 5 are views similar to figure 1 but showing different combinations of specific individual modules. The terms "forward", "rearward", "left" and "right" used in connection with the combine harvester and/or components thereof are determined with reference to the direction of forward operative travel of combine harvester but should not be considered as limiting. Also, the terms "grain", "straw", and "tailings" are used principally throughout this specification for convenience and it should be understood that these terms equally are not intended to be limiting. Thus "grain" refers to that part of the crop which is threshed and separated from the discardable part of the crop material which is referred to as "straw". Incompletely threshed ears are referred to as "tailings". With reference to the figures, the combine harvester comprises the so-called base unit which basically consists of the entire machine less the header 1 and the straw elevator 6. The header as shown in the drawings is a so-called grainheader, but could be of any other type such as e.g. a corn header or a window pick-up attachment, depending on the type of crop and the condition of the crop to be harvested. The header 1 therefore conventionally forms a separate module and is detachably mounted on the forward end of the straw elevator 6. The header 1 shown in the drawings comprises a header through 2 with cutter means (not shown) at its forward end and a header auger 3 rearwardly thereof. The header auger 3 is arranged to transversely consolidate harvested crop material and to convey this crop material through an outlet 4 disposed centrally in the rearwall of the header 1 and which communicates with the straw elevator 6. The header 1 conventionally further also comprises a reel 5 which is a further sub­ assembly or module which is detachably mounted on the header through 2 at a position above and partially forwardly of the cuttermeans and which may be interchangeable with a reel of a different type. As is generally known in the art, the elevator 6 is formed as another sub-assembly which can easily be mounted at the forward end of the base unit generally at the threshing portion thereof and which can be adjusted angularly relative to the base unit by means of hydraulic lifting cylinders (not shown). The straw elevator 6 comprises a box-like framework of generally rectangular cross-section and houses conveyor means (not shown) which, in use, are operable to convey crop material received from the header 1 to the threshing means 7. With reference to figures 1 to 5, the base unit of the combine harvester mainly comprises threshing means 7, separating means 8 and cleaning means 9. The threshing means 7 are operable to thresh crop material fed thereto, i.e. the crop material (which may be wheat, corn, rice, soybeans, rye, grass seed, barley, oats or other similar crops) is rubbed and beaten, whereby the grain, seed or the like, is loosened and separated from the straw, stalks, coils or other discardable part of the crop. The separating means 8 receive threshed crop material from the threshing means 7 and subject said crop material to a further separating action whereby grain not already separated from the rest of the crop material in the threshing means 7 is separated therefrom in said separating means 8. Grain which has been separated from the straw in the threshing means 7 and the separating means 8 is conveyed to the cleaning means 9 which is operable to separate chaff and other impurities from the grain on the one hand and to separate unthreshed or incompletely threshed material (known in the art as "tailings") from the clean grain on the other hand. Cleaned grain is then elevated into a graintank 10 and the tailings either are returned to the threshing means 7 for a repeat threshing action or are subjected to a renewed threshing action in separate tailings rethresher means whereafter said tailings are recycled through the cleaning means 9. The base unit further also comprises a power source 11 which is operatively coupled to the various machine components for driving these components and to combine propulsion means for making the combine harvester mobile. The combine harvester normally comprises a front pair of traction wheels 12 and a rear pair of steerable wheels 13. An operator's station 14 often provided within an operator's cab 15 and comprising an operator's seat 16 and all necessary controls, is provided generally at the forward end of the base unit and at a raised position so as to enable the operator, when positioned on the operator's station, to overview the harvesting operation of the header 1. The combine harvester further also comprises a strawhood 17 which is attachable to the rear of the machine. The invention is concerned basically but not exclusively, with the threshing means 7, the separating means 8 and the cleaning means 9 which are provided in modules; said modules being interchangeable with other modules comprising respectively different types of threshing means 7, separating means 8 and cleaning means 9. With reference to figure 1, a combine harvester is shown; which, as far as the threshing means 7 and the separating means 8 are concerned, is indicated in the art as being "conventional". The cleaning means 9 thereof are not "conventional" as will be explained furtheron. Considering first the threshing means 7, it will be seen that these are provided within a threshing module 20 which is arranged to be detachably mounted on top of a cleaning module 50 at the forward end thereof. This threshing module 20 is equally well mountable on top of the cleaning module 40 shown in figures 2 to 5. To this end, the threshing module 20 has a framework 21 of a width corresponding to the width of the cleaning module framework 51 and comprises side walls 22 which are attachable to the respective fore-and-aft main beams 52 of the cleaning module 50. The threshing means 7 in the threshing module 20 comprise a conventional threshing cylinder 23 which is rotatable around a transverse axis and which is cooperable with a conventional threshing concave 24. This concave 24 extends generally circumferentially around a portion of the threshing cylinder 23 at a small distance therefrom to define a gap therebetween through which, in use, crop material is urged in a generally rearward direction while subjecting said crop material to a threshing action. The threshing means 7 further also comprise a so-called straw deflector beater 25 which is rotatably mounted within the threshing module 20 in parallel and crop receiving relationship with the threshing cylinder 23 and rearwardly thereof. The beater 25 is rotatable in the same direction as the threshing cylinder 23 and is cooperable with a stationary deflector beater grate 26 mounted therebelow. As is generally known in the art, the deflector beater 25 and associated grate 26 are operable to receive threshed crop material from the threshing cylinder 23, to deflect the path of movement thereof and to direct it to a further crop processing component in the machine while subjecting it to a further threshing action. Threshed grain is separated through the threshing concave 24 and the grate 26 and is allowed to fall onto the cleaning means 9 in the cleaning module 50 therebelow. The threshing means 7 as described above and comprising the threshing cylinder 23 and concave 24 together with the deflector beater 25 and associated grate 26 possibly are the simpliest, least expensive and most commonly used threshing means which are known since many decades and which have been fully satisfactory in most circumstances. The framework 21 of the threshing module 20 is adapted for attaching to the top thereof the graintank module 10, which, except for the fact that it is also built according to the modular concept, is fully conventional and bascially comprises a tank body 60, a grain tank unloading auger 61 and an unloading tube 62. The tank body 60 is adapted to be detachably connected to the sidewalls 22 of the threshing module framework 21 which have upper edges 63 which are shaped to match with said body 61. The framework 21 of the threshing module 20 further also is adapted for detachably coupling thereto at the forward end thereof, on the one hand, the header and the straw elevator combination 1 to 6 and, on the other hand, the module of the operator's station 14, which, as already mentioned, may be completed with the operator's cab module 15. The modules forming the grain tank, the operator's station eventually completed with the operator's cab, the header and the straw elevator as used in the combination shown in figure 1 also may be used in other combinations, some of which have been shown in figures 2 to 5, although it also will be appreciated that anyone or more of these modules may be interchangeable with modules of a different type. As an example different size grain tank modules 10 may be available to accommodate the end user's wishes. Also, and as generally known in the art, a range of headers of varying widths is normally available. Turning now to the separating means 8 shown in figure 1, it will be seen that these are formed by a plurality of conventional straw walkers 31 which are mounted for generally back-and-forth oscillatory movement in the lengthwise direction of the machine within a separating module 30 including a framework 32. The framework 32 has the same width as the framework 51 of the cleaning module 50 and the framework 21 of the threshing 20 so that the separating module 30 matches with the threshing module 20 and the cleaning module 50. The side walls 33 of the framework 32 are detachably connectable, on the one hand, to the rear portions of the main beams 52 of the cleaning module 50 at the upper edge thereof and, on the other hand, to the rear edges of the side walls 22 of the threshing module 20. When the separating module 30 is mounted within the combine harvester, the straw walkers 31 thereof have their forward ends in crop receiving relationship relative to the straw deflector beater 23 and associated grate 24 and, in use, are operable to convey threshed crop material thereover for ultimate discharge from the machine at the rearward end thereof while subjecting said crop material to a further separating action to separate further grain loosened from the ears but not already separated from the rest of the crop material in the threshing means 7. It will be seen from figure 1 that the foreward ends of the straw walkers 31 extend forwardly beyond the foreward edges of the framework 32 in a manner to project into the threshing module 20 when mounted on the combine harvester. In operation, separated grain is allowed to fall onto the cleaning means 9 in the cleaning module 50 for further processing. The separating means 8 in the form of straw walkers 31 are simple and rather inexpensive in design and are known in the art already for many decades. The separating capacity thereof is rather limited. Sometimes, this type of separating means is found to be the capacity limiting factor of a combine harvester. Accordingly, there are end users who consider straw walkers to be old fashioned although by many other end users, they are considered to be reliable and to have an advantage over rotary separating means to the extent that straw walkers treat straw more gently than rotary separating means whereby they produce less short straw which in turn results in a more moderate loading of the cleaning means 9. For these reasons, straw walkers may be found to be ideal separating means for brittle straw conditions which prevail in e.g. the Southern part of Europe and provided the capacity requirements are not put too high. Straw walkers also may be considered to be the ideal type of separating means in those circumstances where threshed straw still has an appreciable value to the extent that straw walkers indeed produce better quality straw which furthermore is better baleable with less straw being lost. The strawhood module 17 is detachably connectable to the rear of the separating module 30 and the framework 32 further also is adapted to receive the power source 11 on its upper end. Turning now to the cleaning module, it should be remarked that the cleaning module 50 shown in figure 1 is a more sophisticated one while that a simplier cleaning module 40 is shown in the figures 2 to 5. it will be appreciated however that this simplier cleaning module 40 equally well fits under the threshing module 20 and separating module 30 as shown in figure 1 and as already mentioned hereabove. Considering first the simplier cleaning module 40 shown in figures 2 to 5, it will be appreciated that it basically comprises a mobile framework 41 of rectangular shape supporting the cleaning means 9. The rectangular framework 41 comprise a pair of fore-and-aft extending main beams 42 coupled to each other at their forward ends by a transverse wheel axle 43 supporting also at its opposite ends the traction wheels 12. A transverse rear beam (not shown) completes the rectangular framework 41 at the rear end thereof and pivotably supports at its central portion a steering wheel axle 44 which in turn supports at its opposite ends the steerable wheels 13. As the rectangular framework 41 has to carry most of the weight of the combine harvester it is made really strong. The framework 41 further also supports combine propulsion means (not shown) which are operatively coupled to the traction wheels 12 to make the combine harvester mobile and which may be either of the mechanical or the hydraulic type. The cleaning means 9 supported in the cleaning module 40, basically comprise a grain pan 45, a cleaning shoe with upper and lower cleaning sieves and a cleaning fan 47, as is conventional. The grain pan 45 is mounted on the framework 41 for generally back-and-forth oscillatory movement in the longitudinal direction of the machine generally below the threshing module 20. The grain pan 45 itself is conventional in design and therefore needs no further explanation. The grainpan 45 is mounted in threshed grain receiving relationship with the threshing means 7 and the separating means 8 and, in use, is operable to convey this threshed grain to the cleaning shoe which is disposed rearwardly thereof. The cleaning shoe, as already mentioned, normally comprises upper and lower cleaning sieves, only the upper one of which can be seen in the drawings at 46. The upper and lower cleaning sieves equally are arranged to oscillate back-and-forth generally in the longitudinal direction of the machine to convey threshed grain therealong while subjecting it to a cleaning action. Preferably the upper sieve 46 and the grain pan 45 are oscillated in phase while that the lower sieve is oscillated with a phase difference of 180 degr. relative to the upper sieve 46. The cleaning fan 47 is mounted below the grain pan 45 and is disposed to direct a cleaning air blast through the threshed grain as it passes from the grain pan 45 to the upper cleaning sieve 46 on the one hand and as it is conveyed along the sieves on the other hand whereby chaff and other impurities are made airborne for discharge from the combine harvester. Tailings are separated from the clean grain for recycling as will be explained furtheron in more details and clean grain is collected at the lower end of the cleaning means 9 whereafter it is conveyed through a clean grain elevator (not shown) to the grain tank module 10 for temporary storage therein. The clean grain elevator itself also may be in the form of a module which is detachably connectable between the cleaning module 40 and the grain tank module 10. The tailings separated in the cleaning means 9 normally are recycled back to the threshing module 20 through a return conveyor module 90 for repeated threshing action. This return conveyor module 90 normally is an auger type conveyor which extends between the cleaning module 40 and the threshing module 20 along one side of both of said modules. The return conveyor module 90 is detachably connected at its receiving end to the transverse tailings collecting conveyor 91 which equally is of the auger type and which extends beneath the cleaning means 9 and beyond one side thereof. The tailings return conveyor module 90 is provided with a thrower 92 at its discharge end which is adapted to throw tailings transversely across the width of the threshing module 20 at a location generally forwardly of the threshing cylinder 23. Alternatively, the tailings return conveyor module may comprise a separate tailings rethresher means for rethreshing the tailings as they pass through the return conveyor module and in which case, the tailings no longer have to be recycled back to the threshing module 20. In this case, the tailings return conveyor module has its discharge end positioned at a level slightly above the grain pan 45 in a manner to recycle rethreshed tailings back through the cleaning means 9 in the cleaning module 40. A tailings rethresher and return conveyor of this type is shown and described in more details in GB.2051.541 the content of which is included in the present disclosure by reference. When all modules described so far are put together the combine harvester is not yet complete to the extent that drives, shieldings and eventual optional attachments still should be installed. These components have not been shown in the drawings for the sake of clarity of the disclosure. The drives, which usually are of the mechanical type such as belt or chain drive transmission, extend alongside the various modules and often overlap two or more modules. Drive transmissions which extend between components of only one module, of course, may be installed during the assembly of this specific module, i.e. prior to the putting together of the various modules to form a combine. After the installation of the drives, also the shieldings still have to be installed to shield the drives for making the machine safe and for providing its final appearance. These shieldings also often overlap two or more modules. Normally a range of optional attachments is available. One such attachment is the straw chopper which is mounted within the strawhood 17. Such attachments usually are installed only upon delivery of a machine to the end user. A combine harvester comprising the threshing module 20 and the separating module 30 as shown in figure 1 and the cleaning module 40 as shown in figures 2 to 5 may be considered as a "standard" or fully "conventional" combine which may be the ideal machine for harvesting in brittle straw conditions on bevel terrain and where the demand for capacity is moderate and the cost price of the machine is a limiting factor for the end user. It will be appreciated that the modules may be available in a range of widths so as to enable the manufacturer to offer a range of "conventional" combines. As an example, the separating module 30 may come with 3, 4, 5 or 6 straw walkers 31 and four straw elevator modules 6, four threshing modules 20 and four cleaning modules 40 of corresponding widths may come along therewith to match with these separating modules 30 of different widths. Along therewith, also a range of engines of course also will be made available. Coming back to the cleaning module 40, it is remarked that the cleaning means 9 therein may be more sophisticated than those shown in the figures 2 to 5. It will be appreciated e.g. that between the grain pan 45 and the cleaning shoe a so-called pre-cleaning sieve and intermediate grain pan may be provided. Also the cleaning fan may be of a different type and e.g. may have two outlets. Such components are shown in GB 2.063.037 the disclosure of which is included herein by reference. All cleaning means described so far are particularly adapted to operate on level terrain. When operated in hilly conditions, the cleaning capacity thereof is greatly reduced and moreover, unacceptable grain losses are likely to occur. For these hilly conditions, the invention proposes to interchange the "standard" cleaning module 40 with a further cleaning module 50 which is operable to compensate for the adverse influences on the cleaning function of operation in hilly conditions. Various approaches have been proposed in this respect. One such approach is shown in DE 33.32.763 following which the cleaning sieves and the grain pan are arranged to oscillate back-and-forth in a direction which deviates from the longitudinal direction of the machine; this deviation depending on the direction and the degree of the slope of the field on which the combine is operating. The arrangement is such that grain to be cleaned on the grain pan and the sieves is urged in the direction of the higher side of the cleaning means in an attempt to maintain an even loading of the cleaning means across the transverse width thereof. As is known in the art, unless special precautions are taken, operation on hillsides always results in an uneven loading of the cleaning means with the lower side thereof being overloaded. This is the reason for the reduced cleaning capacity as well as for the unacceptable grain loss level. Another approach to overcome this problem of operation in hilly conditions is shown in GB 2.052.238, the disclosure of which is included herin by reference. The same arrangement is schematically shown in figure 1. Basically, the cleaning means 9, i.e. the grain pan 45, the cleaning shoe with the sieves therein and the cleaning fan 47, are mounted on a pivot frame (not shown) which itself is mounted for pivotal movement around a fore-and-aft extending pivot axis relative to the cleaning module framework 51. The arrangement is such that, when the harvester is inclined transversely relative to the vertical due to operation on a slope, the pivot frame with the cleaning means thereon is pivoted in the opposite direction to assume a generally horizontal position as seen in the transverse direction of the machine. This leveling is obtained automatically by means of an inclinometer which is arranged to control the actuation of position control means for the pivot frame. This self-leveling of the cleaning means 9 is very effective to the extent that it neutralises all adverse influences on the cleaning function of operation of hilly conditions. As already mentioned, figure 1 shows this arrangement only very schematically. As a matter fact, only the forward central bearing 53 and the pair of rearward bearing rollers 54 for movably supporting the pivot frame on the cleaning module framework 51 are shown. It will be appreciated that the framework 51 and more expecially the main beams 52 thereof are shaped and dimensioned to accommodate the pivot frame therebetween. Thus this framework 51 is different from the framework 41 of the "standard" cleaning module 40. However, in any event, the framework 51 has its upper edges dimensioned and shaped so as to match with the threshing and separating modules 20, 30 already described. The cleaning means 9 mounted within the pivot frame of the further cleaning module 50 may be identical to the cleaning means 9 in the "standard" or first cleaning module 40. While that in the preferred embodiment of the further cleaning module 50, the grainpan 45, the cleaning shoe with both cleaning sieves therein and the cleaning fan 47 all are mounted on the pivot frame for self-­ leveling operation as a unit, it will be appreciated that it is also possible to make only either one or both cleaning sieves self-leveling. Alternatively sections of the cleaning sieves may be made self-leveling. Following still another alternative, one or both cleaning sieves together with the grain pan may be made self-leveling. It will be evident that in all these alternative arrangements the pivot frame will have to be adapted accordingly. However, in any event the cleaning module framework always matches with the threshing module 20 and the separating module 30. Turning now to figure 2, it will be seen that the threshing module 27 shown therein is slightly different from the module 20 shown in figure 1. This second threshing module 27 not only comprises the threshing cylinder 23 and associated concave 24 togehter with the deflector beater 25 and the associated grate 26, but further also comprises a thrid rotatable element and an associated stationary element. This third rotatable element is a rethresher cylinder 28 which extends parallel to the threshing cylinder 23 and the beater 25 and is rotatable in the same direction. The stationary element is a rethresher concave 29 positioned at a small distance from the rethresher cylinder 28 so as to define a gap therebetween for the passage of crop material therethrough. As crop material is passed therethrough, it is subjected to a further threshing and separating action, whereby further grain is separated from the crop material through the rethresher concave 29 and is allowed to fall onto the cleaning means 9. Rethresher means as described hereabove have been shown and described in GB 1.318.071, the disclosure of which is included herein by reference and to which is referred for more details. The various components in the second threshing module 27 may be proportionally smaller so as to make sure that the discharge ends of the threshing means 7 in both the first and the second threshing module 20, 27 are situated at precisely in the same location whereby the second threshing module 27 is interchangeable with the first threshing module 20 and matches with the first separating module 30 already described herebefore and shown in figure 1. The frameworks 21 of both threshing modules 20 and 27 have the same length. Alternatively and indeed also preferably and as shown in figure 2, the threshing cylinder 23 and concave 24 together with the beater 25 and grate 26, as used in the second threshing module 27, may be identical to the corresponding components of the first threshing module 20, whereby the location of the discharge end of the threshing means in the second threshing module 27, i.e. of the rethresher means 28, 29, is different from the location of the discharge end of the threshing means 7 in the first threshing module 20, i.e. of the beater 25 and grate 26. Also preferably the frameworks 21 in both modules have the same length and indeed even may be identical, whereby, in the combination of the first threshing module 20, cover plates are needed to close off the mounting holes in the side walls 22 for the rethresher shaft and the rethresher concave mounting pins. It will be appreciated that the first separating module 30 shown in figure 1 will not match with the foregoing version of the second threshing module 27 to the extent that, when both modules were assembled on either a first or further cleaning module 40, respectively 50, the straw walkers 31 thereof would interfere with the rethresher means 28-29. Accordingly, a second separating module 34 with shorter straw walkers 35 is available for combining with the aforementioned version of the second threshing module 27. When both the second threshing module 27 and the second separating module 34 are mounted on any one of the cleaning modules 40 or 50, the straw walkers 35 have their forward ends positioned in crop receiving relationship to the discharge end of the rethresher means 28, 29. When comparing the separating modules 30 and 34 as shown respectively in figures 1 and 2 it will be seen that the straw walkers 31 of the first separating module 30 have six "steps" while that the straw walkers 35 of the second separating module 34 have only five "steps". It will also be noted that the straw walkers 35 of the second separating module 34 do not extend forwardly into the second threshing module 27. Instead the rethresher means 28-29 of the second threshing module 27 extend over a short distance within the second separating module 34. Again the framework 36 of the second separating module 34 has the same width as the framework 21 and 41, 51 of the first and second threshing modules 20 and 27, respectively the first and second cleaning modules 40 and 50 for enabling the sidewalls 37 thereof to be detachably connected to the side walls 22 on the one hand and the main beams 42 or 52 on the other hand. According to still another alternative apporach the threshing cylinders 23 and concaves 24 together with the beaters 25 and grates 26 in both the first and second threshing modules 20, 27 again are identical. However, the framework of the first threshing module 20 is correspondingly shorter than the framework of the second threshing module 27; the arrangement being such that the threshing means 7 in both modules 20, 27 have their discharge ends at precisely the same location relative to the rear edge of the respective frameworks. Under this condition, and provided the second separating module 34 is positionable in any one of two positions on the cleaning module 40/50, this second separating module 34 with shorter straw walkers 35 can be made to match with as well the first threshing module 20 as the second threshing module 27. The use of the second threshing module 27 including the rethresher means 28, 29 in combination with a separating module 34 of the straw walker type is recommended where the straw walkers of the "standard" combination are felt as the capacity limiting factor of the combine harvester and where there is a demand for a higher capacity. The rethresher means 28-29 indeed improve to a great extent the separating capacity of the threshing and separating means 7-8. This may be to the detriment of the straw quality as said rethresher means 28-29 are somewhat more aggressive, which is why the rethresher means 28-29 should be recommended only when the straw to be harvested is somewhat tougher i.e. less brittle. In any event, the combination with rethresher means 28-29 is still very much less agressive to the straw than the rotary separating means known today. Furthermore, as far as cost is concerned, the combination including the rethresher means 28-­ 29 still may be considered to belong to the lower range. Turning now to figure 3, it will be noticed that the combination shown therein is basically the same as the combination shown in figure 2, except for the fact that the second separating module 34 of figure 2 is replaced by a third separating module 65 which is of the rotary type. The rotary separating means 8 therein are of the single flow type and as such are of an offset design with an inlet 66 at one end for communication with the rethresher means 28-29 and an outlet (not shown) at the other end. These rotary separating means 8 comprise a separating rotor 67 surrounded by a separating housing including separating concaves (not shown). These separating means 8 again extend parallel to the rotatable components in the threshing module 27 and the rotor 67 equally is rotated in the same direction as said threshing components. The separating rotor 67 and associated separator housing have a width which exceeds the width of the threshing module 27 and the cleaning modules 40, 50. The framework 68 of this third separating module 65 is such that, when mounted in a combine harvester, the separating means 8 have one end generally aligned with the corresponding sides of the threshing module 27 and of the cleaning module 40, 50. The other end of the rotary separating means 8 thus extends beyond the corresponding other sides of the threshing module 27 and the cleaning module 40, 50. In operation, crop material is received from the rethresher means 28, 29 through the inlet 66 and is conveyed spirally around the rotor 67 towards the offset outlet for discharge therethrough while subjecting said crop material to an aggressive separating action. Grain separated in the portion 69 of the separating means 8 overlying the cleaning module 40, 50 is permitted to fall directly thereto. Instead, grain separated in the portion of the separating means 8 offset from the cleaning module 40, 50 is conveyed to this cleaning module via a further conveying module 95 which has a dual function to the extent that it also is operable to recycle half of the tailings separated in the cleaning means 9 back to the grainpan 45. With respect to this tailings recycling function, the module 95 is very similar to the conveyor module 90 already described and which in the combination presently under consideration is also being used. Indeed, the tailings collecting conveyor 94 in this combination is operable to convey half of the tailings separated in the cleaning module 40, 50 to one side thereof and the other half of the tailings to the opposite side. The first conveyor module 90 including, as already described, a special tailings rethresher, is provided at one side of the cleaning module 40, 50 and is operable to rethresh and recycle one half of the tailings back to the grain pan 45. The further conveyor module 95 is provided at the other side of the cleaning module 40, 50 and equally includes a special tailings rethresher. This further conveyor module 95 is connected to the corresponding end of the tailings collecting conveyor 94 and also has at its discharge end a thrower means 96 which is arranged to spread recycled to material transversely across the width of the grain pan 45. The further conveyor module 95 also has a receiving trough 97 intermediate its ends and which is coupled to the underside of that portion of the separating means 8 which extend beyond the corresponding side of the cleaning module 40, 50 for receiving grain which is separated therein and for conveying said grain, together with rethreshed tailings, to the grain pan 45 for subjecting it to a cleaning action. A conveyor module of this type is shown in more details in GB 2051541, the disclosure of which is included herin by reference. The straw hood 17 which matches with the third separating module 65 is somewhat different from the straw hood 17 which matches with the straw walker type separating modules 30, 34. The combination illustrated in figure 3 forms a so-called "rotary" combine and is particularly attractive when the separating module 65 is combined with relatively narrow threshing and cleaning modules 27, 40, 50. Such a combination forms a relatively low cost rotary combine which nevertheless has an exceptionally high capacity especially when harvesting corn. This combination therefore typically is a corn combine although, as it will be appreciated, it also can handle other crops. Turning now to figure 4, it will be noticed that, in comparison with figure 3, basically only the thrid separating module 65 has been replaced by a fourth separating module 75 which again is of the rotary type. Again, a separating rotor 76 is provided which extends parallel to the rethresher cylinder 28 in the threshing module 27 and which is rotatable in the same direction as this rethresher cylinder 28. The separating rotor 76 again is mounted within a separating housing comprising separating concaves 77. Again the separating means 8 have a greater width than the threshing module 27 and the cleaning module 40, 50 with which is it to be combined. However, in this combination the separating means 8 are fully symmetrical relative to the fore-and-aft vertical plane of symmetry of the combine harvester. In other words, the threshing module 27 and the separating module 75 have a common fore-and-aft vertical plane of symmetry. Accordingly, the separating module 75 extends an equal length beyond each side of the threshing module 27 and the cleaning module 40, 50. The framework 78 nevertheless is dimensioned and positioned so as to be detachably connectable to the side walls 22 of the threshing module 27 and to the main beams 42, 52 of the cleaning module 40, 50. The separating housing has a central forwardly facing inlet 79 of substantially the same width as the threshing module 27 and which is positioned to communicate therewith. The layer of crop material is received from the rethresher means 28-29 through the inlet 79 whereafter it is divided in two generally equally sized halves by layer dividing means (not shown) provided generally at or proximate to the fore-and-aft plane of symmetry. The separating means 8 further are operable spirally to convey said halves in opposite directions around the rotor 76 towards its opposite ends for ultimate discharge through outlets (not shown) at these ends. During these spiral movements through the separating means 8, the crop material is subjected to an aggressive separating action. Grain separated in the central portion of the separating module 75 is allowed to fall directly to the cleaning module 40, 50. Instead, grain which is separated in the portions of the separating module 75 extending beyond the respective opposite sides of the cleaning module 40, 50 is conveyed to the grain pan 45 by dual purpose conveyor modules 95 identical to the conveyor module 95 already described in the combination according to figure 3 and which thus not only convey said separated grain to the grainpan 45 but furthermore also recycle tailings in the cleaning means 9. One such conveyor module 95 is provided on each side of the cleaning module 40, 50 which means that this cleaning module 40, 50 in this combination, also has a tailings collecting conveyor 94 which conveys half of the tailings in one direction and the other half in the other direction. As already indicated, further details of a conveyor means similar to the conveyor modules 95 can be taken from GB 2051541, the disclosure of which is included herein by reference. The combination of the threshing means 7 and the separating means 8 as used in the combination of figure 4 equally has been shown and described in more details in GB 2063039, the disclosure of which equally is included herein by reference. The fourth separating means 75 described hereabove preferably, though not exclusively, are combined with relatively wide threshing and cleaning modules 27, 40, 50 so as to form a truely high capacity rotary combine with a particularly aggressive separating action and which can cope without any difficulties with crops having a high moisture content such as often is the case with corn. However this type of rotary combine further als0 has a very high throughput capacity in so-called "small grains" such as e.g. wheat. This type of rotary combine can handle quite easily tough crop conditions which sometimes present problems to so-called axial flow type rotary combines (figure 5). Thus, the combine illustrated in figure 4 is a "top of the range" combine for which cost is less critical. Such a combine eventually may produce straw of a lesser quality. Returning once more to the combinations illustrated in both figures 3 and 4, it will be appreciated that the threshing modules therein preferably are of the type including the rethresher cylinder 28 and concave 29, i.e. the threshing module 27 although it also will be appreciated that the separating modules 65 and 75 nevertheless also may be combined with a threshing module having no such rethresher means 28-29, such as e.g. the threshing module 20. Turning now finally to figure 5, it will be noticed that the various threshing and separating module 20, 27 respectively 30, 34, 65, 75 as shown in anyone of the figures 1 to 4 have been replaced in this combination by a single module 80 comprising combined threshing and separating means 7, 8 of the axial flow type. The framework 81 thereof again has a width which corresponds to the width of the cleaning module 40, 50 to which it is attachable. This framework 81 further also is adapted to support at its upper end the grain tank module 10 and rearwardly thereof the power source 11. The operator's station module 14 and the straw elevator and header combination 6, 1 are coupled to the forward end of this combined threshing and separating module 80 and the straw hood 17, which again may be of a different shape and dimension, is attachable to the rear end thereof. The threshing and separating means 7-8 comprise at least one rotor 82 which is rotatably mounted within a corresponding housing including at least one threshing concave 83 and one separating concave 84. The at least one threshing and separating rotor 82 is rotatable around a generally fore-­ and-aft extending axis and comprises a threshing section 85 forwardly of a separating section 86. The rotor 82 further also comprises a feeder section 87 forwardly of the threshing section 85 for receiving the layer of crop material from the straw elevator 6 and for changing it's path of movement from a generally rectilinear path in the straw elevator into a generally spiral path in the threshing and separating means 7-8 and extending therealong from front to rear. As crop material is conveyed spirally through the threshing and separating means, it is subjected to an aggressive threshing and separating action. Preferably two threshing and separating rotors 82 are provided in corresponding housings in parallel relationship relative to each other. The feeder sections 87 in this case, are operable to divide the crop layer received from the straw elevator 6 in two substantially equally sized halves, one of which spirally is conveyed around one rotor 82 and the other one of which spirally is conveyed around the other rotor 82. Generally at the rear end of the rotors 82, a discharge beater 88 and corresponding grate 89 are provided; the beater 88 being rotatable around a transversely extending axis. The discharge beater and grate 88-89, in operation, receive threshed crop material (straw) from the rotors 82 and discharge it rearwardly through the strawhood 17. As this crop material is passed across the beater grate 89 it is subjected still to a final separating action. Grain separated through the threshing and separating concaves 83, 84 and through the beater grate 89 is allowed to fall directly to the cleaning module 40, 50 therebelow. As the combined threshing and separating module 80 has the same width as the cleaning module 40, 50 therebelow, there is no need for a conveyor module 95 of the type as described with reference to e.g. figure 4 for conveying separated grain to the cleaning means 9. For recycling tailings separated in the cleaning means 9 a conveyor module 90 of the type as described with reference to e.g. figure 1 is provided. A combine harvester embodying the combined threshing and separating means as used in the combination according to figure 5 is shown and described in GB 1.399.601, the disclosure of which is included herein by reference. The combination as shown in figure 5 typically is a high capacity rotary combine, which is particularly appealing for use in dry crop conditions, which is more "straw friendly" than the rotary combine illustrated in figure 4 and which probably produces the best grain sample (i.e. minimal percentage of damaged grain) in the business which, in certain areas is a very important criterion. This combination further also is a typical high capacity corn combine. In general, it thus will be appreciated that the invention enables the manufacturer to offer a wider range of combines with a relatively small number of parts and at an "acceptable" cost. Thus, greater flexibility is provided to meet the customer's demand. Also the invention facilitates the application of the principles of "model mix" by the manufacturer during assembly. Fewer spare parts have to be stocked at the manufacturer's and dealer's levels and less dealer training is required. It will be understood that changes in the details, materials, steps and arrangement of parts, which have been described and illustrated to explain the nature of the invention, will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates several embodiments of the invention; however, concepts, as based upon the description may be employed in other embodiments without departing from the scope of the invention.

Claims: 1. A combine harvester comprising : - a header (1) adapted for receiving crop material from the field; - threshing means (7) for threshing crop material received from the header (1) and separating grain therefrom; - separating means (8) disposed to receive threshed crop material from the threshing means (7) and operable to separate further grain from the crop material which has not previously been separated therefrom by the threshing means (7). - cleaning means (9) positioned to receive threshed and separated grain from the threshing means (7) and the separating means (8) and operable to separate clean grain from discardable crop material; - grain storage means (10) operable to temporarily store clean grain received from the cleaning means (9); - a power source (11) operatively coupled to the various machine components for driving said machine components; and - an operator's station (14) with controls for enabling the operator to control the harvesting operation; the combine harvester being of a modular design and including at least a threshing module (20), a separating module (30) and a cleaning module (40) detachably connected to each other in an operational manner; characterised in that at least one module (20,30,40) is interchangeable with another module (27/34,65,75/50/80) of a different type. 2. A combine harvester according to claim 1, characterised in that : - the threshing module (20) is of the type comprising : . a threshing cylinder (23) cooperable with a threshing concave (24) and . a deflector beater (25) and associated beater grate (26) mounted parallel to and in crop receiving relationship rearwardly of the threshing cylinder (23) and threshing concave (24); the threshing cylinder (23) and the deflector beater (25) being rotatable around transversely extending axes and in a direction to convey crop material across the threshing concave (24) and the beater grate (26) while subjecting said crop material to a threshing and separating action; and - the separating module (30) is disposed to receive threshed crop material from the threshing module (20) and is of the type comprising a plurality of straw walkers (31) arranged to oscillate back-and-forth generally in a longitudinal direction of the machine in a manner to convey threshed crop material thereover while subjecting said crop material to a further grain separating action. 3. A combine harvester according to claim 2, characterised in that : - the threshing module (20) is detachably connected to the forward portion of the cleaning module (40) at the upper side thereof, and, - the separating module (30) is detachably connected to the rearward portion of the cleaning module (40) at the upper side thereof on the one hand and to the threshing module (20) at the rearward side thereof on the other hand. 4. A combine harvester according to claim 2 or 3 characterised in that : - the threshing module (20) as specified is interchangeable with a further threshing module (27) of the type comprising : . a threshing cylinder (23) cooperable with a threshing concave (24); . a deflector beater (25) and associated beater grate (26) mounted parallel to and in crop receiving relationship rearwardly of the threshing cylinder (23) and threshing concave (24); and . a rethresher cylinder (28) and associated rethresher concave (29) mounted parallel to and in crop receiving relationship rearwardly of the deflector beater (25) and associated beater grate (26); the threshing cylinder (23), the deflector beater (25) and the rethresher cylinder (28) being rotatable around transversely extending axes in a direction to convey crop material across the threshing concave (24), the beater grate (26) and the rethresher concave (29) while subjecting said crop material to a threshing and separating action. 5. A combine harvester according to claim 4 characterised in that : - the threshing module (20) and the further threshing module (27) have the same lengthwise dimension and both have the threshing means (23/24) positioned therein in a manner for, when installed in the combine harvester forwardly of the separating module (30), operatively transferring threshed crop material to the separating means (8) in the separating module (30) as said threshed crop material issues from the threshing module (20), respectively the further threshing module (27). 6. A combine harvester according to claim 4 characterised in that : - the further threshing module (27) has a greater lengthwise dimension than the first threshing module (20) and - the separating module (30) is positionable in different lengthwise positions on the cleaning module (40) to operatively match with whatever threshing module (20/27) is installed in the combine harvester. 7. A combine harvester according to claim 4, characterised in that : - the first and further threshing modules (20,27) have the same lengthwise dimensions with substantially the same threshing cylinder (23), threshing concave (24), deflector beater (25) and beater grate (26) provided therein at substantially the same positions, and - the separating module (30) is interchangeable with a further separating module (34) of the type also comprising a plurality of straw walkers (35); the straw walkers (31) of the first separating module (30) extending further forwardly relative to the separating module sub-frame (32) than the straw walkers (35) of the further separating module (34) and the arrangement being such that : . the first separating module (30) matches with the first threshing module (20) so that; when both are installed in the combine harvester, the forward ends of the strawwalkers (31) project into the threshing module (20) in crop receiving relationship relative to the deflector beater (25) and associated beater grate (26), and . the further separating module (34) matches with the further threshing module (27) so that, when both are installed in the combine harvester, the forward ends of the straw walkers (35) thereof are positioned in crop receiving relationship with the rethresher cylinder (28) and rethresher concave (29) 8. A combine harvester according to anyone of the preceding claims; characterised in that the respective threshing modules (20,27) separating modules (30,34) and the cleaning module (40) all have substantially the same transverse width and are connectable to each other with respective transversely opposite sides (22/33,37/42) generally aligned to each other. 9. A combine harvester according to anyone of the claims 1 to 6, characterised in that : - the first or further separating module (30/34) is interchangeable with a third separating module (65) which is of the rotary type and wherein the separating means (8) comprise at least one separating rotor (67) rotatably mounted within a separating housing including at least one separating concave; the separating means (8) being arranged spirally to convey threshed crop material received from the threshing module (20,27) towards one end for discharge therefrom while subjecting said crop material to a further separating action. 10. A combine harvester according to claim 9, characterised in that the rotary separating means (8) of the third separating module (65), when installed in the combined harvester, extend parallel to the threshing means (7) in the first or further threshing module (20,27) with the at least one separating rotor (67) being rotatable around a transverse axis. 11. A combine harvester according to claim 10, characterised in that: - the third separating module (65) has a transverse width greater than the transverse width of the first or further threshing module (20,27) and than the transverse width of the cleaning module (40); said third separating module (65), when installed in the combine harvester, being positioned such that the separating means (8) thereof have their discharge end extending transversely past the corresponding side of the first or further threshing module (20,27) provided forwardly thereof and the corresponding side of the cleaning module (40) provided therebelow. 12. A combine harvester according to anyone of the claims 1 to 6, characterised in that - the first, second or third separating module (30,34,65) is interchangeable with a fourth separating module (75) which is of the rotary type and wherein the separating means (8) comprise at least one transversely extending separating rotor (76) rotatably mounted within a transversely extending separating housing including at least one separating concave (77); the separating means (8) being arranged spirally to convey threshed crop material received from the threshing module (20,27) towards each of its ends for discharge therefrom while subjecting said crop material to a further separating action. 13. A combine harvester according to claim 2 characterised in that : - the first or further threshing module (20,27) and the fourth separating module (75) have a common fore-and-aft plane of symmetry; and - the fourth separating module (75) has a forwardly facing, centrally positioned inlet (79) which, when said separating module (75) is installed in the combine harvester, is disposed to receive a layer of threshed crop material therethrough from the first or further threshing module (20,27); the separating means (8) of the fourth separating module (75) comprising crop layer dividing means generally at or proximate to the fore-and-aft plane of symmetry for dividing said layer of threshed crop material into two substantially equally sized halves whereafter said halves are conveyed spirally in opposite directions through the separating means (8) towards respective outlets generally at the opposite ends of the separating means (8) for discharge therethrough. 14. A combine harvester according to claim 12 or 13 characterised in that : - the fourth separating module (75) has a transverse width greater than the transverse width of the first or further threshing module (20,27) and than the transverse width of the cleaning module (40); said fourth separating module (75), when installed in the combine harvester, being positioned such that the separating means (8) thereof have their opposite ends extending transversely past the respective sides (22) of the first or further threshing module (20,27) provided forwardly thereof and the respective sides (42) of the cleaning module (40) provided therebelow. 15. A combine harvester according to any one of the preceding claims, characterised in that : - the first or second threshing module (20,27) together with the first, second, third or fourth separating module (30,34,65,75) is interchangeable with a combined threshing and separating module (80) which is of the rotary type and wherein the threshing and separating means (7,8) comprise at least one threshing and separating rotor (82) rotatably mounted within a threshing and separating housing comprising at least one threshing concave (83) and at least one separating concave (84); said threshing and separating rotor (82) and associated housing, when the combined threshing and separating module (80) is installed in the combine harvester, extending generally lengthwise of said combine harvester with the rotor (82) being rotatable around a generally fore-and-aft extending axis and the threshing and separating means (7,8) being operable spirally to convey crop material therethrough from front to rear while subjecting said crop material to a threshing and separating action. 16. A combine harvester according to claim 15 characterised in that the at least one threshing and separating rotor (82) comprises a threshing section (85) and a separating section (86) coaxially with and rearwardly of said threshing section (85). 17. A combine harvester according to claim 16 characterised in that the at least one threshing and separating rotor (82) further also comprises a feeder section (87) coaxially with and forwardly of the threshing section (85). 18. A combine harvester according to anyone of the claims 15 to 17 characterised in that the combined threshing and separating module (80) further also comprises crop discharge means (88,89) generally at the rearward end of the threshing and separating means (7,8); said crop discharge means (88,89) comprising a discharge beater (88) which is rotatable around a generally transversely extending axis and which is cooperable with a beater grate (89) positioned therebelow. 19. A combine harvester according to anyone of the claims 15 to 18, characterised in that the combined threshing and separating module (80) comprises two side-by-side extending threshing and separating housings; each housing having a threshing and separating rotor (82) rotatably mounted generally coaxially therein. 20. A combine harvester according to anyone of the preceding claims, characterised in that the cleaning module (40) includes cleaning means (9) of the type comprising : - a grain pan (45) disposed to receive threshed grain from the threshing and separating means (7,8) and arranged to oscillate back-and-­ forth generally in the longitudinal direction of the machine to convey threshed grain lengthwise thereof; - a cleaning shoe including at least one cleaning sieve (46) in grain receiving relationship to the grain pan (45) and arranged to oscillate back-and-forth generally in the longitudinal direction of the machine to convey threshed grain lengthwise thereof while subjecting it to a cleaning action; and - cleansing fan means (47) operable to direct a cleaning air blast through the grain to be cleaned for removing discardable crop material therefrom; the cleaning means (9), when the cleaning module (40) is installed in the combine harvester and, as seen in the transverse direction of the machine, assuming a fixed orientation relative to said machine. 21. A combine harvester according to claim 20, characterised in that the cleaning module (40) as specified is interchangeable with a further cleaning module (50) equally including cleaning means (9) of the type comprising : - grain pan (45) disposed to receive threshed grain from the threshing and separating means (7,8) and arranged to oscillate back-and-­ forth generally in the longitudinal direction of the machine to convey threshed grain lengthwise thereof; - a cleaning shoe including at least one cleaning sieve (46) in grain receiving relationship to the grain pan (45) and arranged to oscillate back-and-forth generally in the longitudinal direction of the machine to convey threshed grain lengthwise thereof while subjecting it to a cleaning action; and - cleaning fan means (47) operable to direct a cleaning air blast through the grain to be cleaned for removing discardable crop material therefrom; but wherein the cleaning means (9) additionally are arranged to compensate for influences on the cleaning operation of the combine harvester operating on an inclination in a transverse direction of the machine. 22. A combine harvester according to claim 21 characterised in that : at least one cleaning sieve (46) of the cleaning means (9) of the further cleaning module (50) or sections thereof is/are arranged to pivot around a/- genarally fore-and-aft extending axis/axes in a manner so that, when the combine harvester is transversely inclined relative to the vertical, said at least one cleaning sieve (46), respectively said sections thereof, is/are pivoted to maintain a substantially horizontal orientation as seen in the transverse direction of the machine. 23. A combine harvester according to claim 21, characterised in that - the further cleaning module (50) comprises a self-leveling sub­ assembly supporting at least one cleaning sieve (46) for back-and-forth oscillatory movement in the longitudinal direction of the machine and which is arranged to pivot around a generally fore-and-aft extending axis in a manner so that, when the combine harvester is transversely inclined relative to the vertical, said at least one cleaning sieve (46) is pivoted to maintain a substantially horizontal orientation as seen in the transverse direction of the machine. 24. A combine harvester according to claim 23, characterised in that the self-leveling sub-assembly supports : - the cleansing shoe with the cleaning sieves (46) therein a manner for enabling the cleaning sieves (46) to oscillate back-and-forth generally longitudianally of the sub-assembly, and - the grain pan (45) also for back-and-forth oscillatory movement in the longitudinal direction of the sub-assembly; the arrangement being such that, when the combine harvester is transversely inclined relative to the vertical, said sub-assembly is pivoted to maintain the cleaning shoe and the grain pad (45) in a substantially horizontal orientation as seen in the transverse direction of the machine. 25. A combine harvester according to claim 24 characterised in that : - the sub-assembly further also supports the cleaning fan (47) in a manner so that the cleaning sieves (46), the grain pan (45) and the cleaning fan (47) are pivotable in unison about the fore-and-aft extending pivot axis so as to maintain the relative positioning of said cleaning sieves (46), grainpan (45) and cleaning fan (47) during the self-leveling operation of the cleaning means (9). 26. A combine harvester according to anyone of the claims 20 to 25, characterised in that : the cleaning module (40) or further cleaning module (50) is mobile and comprises front and rear pairs of wheels (12,13) interconnected by a framework (41,51) supporting the cleaning means (9); the cleaning module (40) or further cleaning module (50) further also comprising combine propulsion means for driving at least one pair of wheels (12). 27. A combine harvester according to anyone of the claims 20 to 26 when appended to anyone of the claims 1 to 8, 11 or 15 to 19, characterised in that : - a return conveyor module (90) extends between, on the one hand, the first or further cleaning module (40,50) and, on the other hand, the first or second threshing module (20,27) or the combined threshing and separating module (80) for recycling from the cleaning means (9) back to the threshing means (7) incompletely threshed crop material (tailings) separated in the cleaning means (9) from the clean grain. 28. A combine harvester according to anyone of the claims 20 to 26 when appended to anyone of the claims 1 to 8, 11 or 15 to 19, characterised in that : - a return conveyor module (90) extends alongside one side of the first or further cleaning module (40, 50) from a position proximate to the lower side of said first or further cleaning module (40, 50) to a position proximate to and above the level of the grain pan (45) therein; said return conveyor module (90) including a tailings rethresher means for rethreshing tailings separated in the cleaning means (9) from the clean grain and the return conveyor module (90) being operable to recycle rethreshed tailings back to the grain pan (45). 29. A combine harvester according to any one of the claims 20 to 26 when appended to claim 11, characterised in that : - a further return conveyor (95) extends alongside the first or further cleaning module (40, 50) at the side thereof beyond which the third separating module (65) projects; said further return conveyor module (95) extending from a position proximate to the lower side of said first or further cleaning module (40,50) past and beneath that portion of the third separating module (65) which projects beyond the corresponding side of the first or further cleaning module (40,50) to a position proximate to and above the level of the grain pan (45) therein; said further return conveyor module (95) including : . a tailings rethresher means for rethreshing tailings separated in the cleaning means (9) from the clean grain and . receiving means (97) intermediate its ends and communicating with said portion of the third separating module (65) for receiving separated crop material from said portion of the third separating module (65); and said further return conveyor module (95) being operable to convey to the grain pan (45) both : . rethreshed tailings received from the cleaning shoe and . crop material separated in the separating means (8) within that portion of the third separating module (65) which extends beyond the corresponding side of the first or further cleaning module (40,50). 30. A combine harvester according to any one of the claims 20 to 26 when appended to claim 14 characterised in that : - at each transverse side of the combine harvester, a return conveyor module (95) is provided which extends from a position proximate to the lower side of the first or further cleaning module (40,50) past and beneath that portion of the fourth separating module (75) which projects beyond the corresponding side of the first or further cleaning module (40,50) to a position proximate to and above the level of the grain pan (45) therein; said return conveyor modules (95) including : . tailings rethresher means for rethreshing tailings separated in the cleaning means (9) from the clean grain and . receiveing means (97) intermediate their ends and communicating with the respective portions of the fourth separating modules (75) which extend beyond the corresponding sides of the first or further cleaning module (40,50) for receiving separated crop material from said respective portions of the fourth separating module (75); and said return conveyor modules (75) being operable to convey to the grain pan (45) both : . rethresher tailings received from the cleaning shoe and . crop material separated in the separating means (8) within said portions of the fourth separating module (75) which extend beyond the corresponding sides of the first or further cleaning module (40,50).

Inventors: CARNEWAL JOSE ANTOINE CYRIEL L., MESURE, GEORGES MARCEL, VAN HERPE, FRANCOIS, Carnewal José Antoine Cyriel L., van Herpe, François
Applicants: FORD NEW HOLLAND N.V.
Application year: 1986
Main classification: A01D41
IPC codes: A01D67, A01D41