GB2148685A - Threshing apparatus - Google Patents

Abstract

A threshing apparatus comprising a plurality of rotary members (3) each having a plurality of threshing teeth (10), wherein the rotary members are rotatable on parallel axes (P) extending in the direction of movement of the reaped crop. The reaped crop is fed in by a feed chain (1) and placed in a substantially straight posture in a direction substantially normal to the axes (P) when in contact with the rotary members (3), and the threshing teeth of adjacent rotary members have addendum circles overlapping one another in a direction parallel to the axes (P). <IMAGE>

Description

SPECIFICATION Threshing apparatus The present invention relates to a threshing appar atuscomprising a plurality of rotarythreshing members arranged parallel to one another, and more particularly to a threshing apparatus in which reaped crop is transmitted parallel to rotational axes of rotary threshing members to receive threshing actions of the rotary threshing members.

Known threshing apparatus incorporated into combine harvesters and other types of harvesters comprise the type in which reaped crop is transmitted parallel to a rotational axis of a rotary threshing member. This type of threshing apparatus consists of the single drum type and the plural drum type. These known threshing apparatus include a threshing drum or drums having a relatively large diameter and a screen or screens of semi-cylindrical shape extending circumferentially ofthethreshing drum or drums. A reaped crop to be treated is placed into a space between the drum and the screen and is bent into an arcuate posture. The crop thus bent and with its foot portion held by a feed chain undergoes a threshing action ofthethreshing drum while being transmitted through the space and parallel to an axis ofthe threshing drum.

With the known threshing apparatus as above, therefore, the crop assumes the bent posture and substantially its entire length (excluding the foot portion) is in contact with the threshing drum,which imparts a strong resistance to the crop transmission.

In otherwords,the known construction is such that the crop is forcibly transmitted by the feed chain parallel to the drum axis against the above-noted resistance.

With the threshing apparatus having such a construction it has been extremely difficultto greatly increase unittime crop treatment.

In recent years it has strongly been desired to greatly increase unit time crop treatment without increasing dimensions ofthethreshing apparatus. It will be appreciated from the above explanation that such a demand is difficultto meet. There is another demand concerning the threshing apparatus for use with combine harvesters and the like, and that is to minimize dimentions, especially vertical demensions, of a threshing chamber housing the threshing drum to permit a grain tank to be installed orto extend to a position abovethethreshing chamber. This is aimed to carry a great amount of chaff in good balance relative to ground wheels and reduce the frequency of discharging grain from the grain tank,therebyto improve operating efficiency.However, the known single drum type or plural drum type threshing apparatus has the threshing drum or drums of considerably large diameter and is incapable of meeting the foregoing requirement.

The present invention has been made having regard to the above state ofthe art, and the principal object of the invention is provide a threshing apparatus comprising a plurality of rotary members each having a plurality ofthreshing teeth, wherein the rotary members are rotatable on parallel axes extending in a direction of movement of reaped crop, the reaped crop being placed in a substantially straight posture in a direction substantially normal to the axes when in contact with the rotary members, and the threshing teeth of adjacent rotary members have addendum circles overlapping one another in a direction parallel to the axes.

According to the present invention, a plurality of rotary members are arranged in directions parallel to a longitudinal direction of crop and include rotary shafts and threshing teeth projecting radially outwardly from the rotary shafts, respectively,the threshing teeth projecting from the rotary shafts and terminating at positions close to surfaces of adjacent rotary shafts.

Therefore, the rotary members includes threshing teeth having addendum circles overlapping with those of adjacent teeth, so that tip ends of teeth of each rotary member pass very close to the rotary shafts of adjacent rotary members. This feature permits the crop to undergo threshing action with an increased frequency, thereby to realize an efficient and speedy threshing operation. What is more important is these rotary members have a much smallerdiameterthan the threshing drums ofthe known threshing apparatus.

In operating the threshing apparatus of the present invention, crop is transmitted from the rotary members at a starting end to the rotary members at 3 terminal end while being maintained substantially in a straight posture and in contact with the plurality of threshing drums (rotary shafts) arranged on a plane longitudinally ofthe crop and being subjected to the threshing action of the rotating threshing teeth.A space between the rotary members and a lid member covering the rotary members is determined such that the crop is kept in contact with the rotary members all along. When adopting a construction and operational mode in which the crop is placed in contact with the rotary members from below, a screen for screening out g rain may set as the lid member.

In one embodiment of the presentthe rotary members are arranged in a single horizontal plane and alternate rotary members have an identical tooth arrangement.

In another embodiment ofthe invention at least those ofthe rotary members adjacent a crop feed opening (orthestarting end) havetooth arrangements differentfrom one another. More particilarly, the teeth closer to ears of the crop (or remote from a feed chain) are disposed progressively downstream in the direction of movement ofthe crop, whereby the conveying forceforthe ears is generated by the rotation of the teeth. This arrangement ensures thatthe ears ofthe crop advance keeping pace with foot portion which is heldandforciblytransmitted bythefeedchain.

Therefore, the crop is free from an excessive combing action, which is of advantage in that development of straw is restrained and threshing efficiency is improved.

In a further embodiment ofthe invention the rotary members are arranged in two planes one above the other. The rotary members in each plane are arranged as in the first embodiment. Two adjacent rotary members, one in the upper plane and the other in the lower plane, again have mutuallyoverlapping addendum circles of threshing teeth. In operating this threshing apparatus, the crop desirably is passed between the upper and lower rotary members although it is possible to pass the crop through upper faces ofthe upper rotary members and through lower faces ofthe upper rotary members and through lower faces of the lower rotary members. Where the crop is passed between the upper and lower rotary members, the threshing teeth act on the crop from both above and belowwhereby no crop ears are leftunthreshed.

An opening may be provided in a certain fixed position in the screen adjacent the feed chain in order to discharge straw resulting from the threshing operation outwardly ofthethreshing apparatus.

However, it is more convenientto provide two or more such openings whose positions are selective, whereby it is adaptableto varying straw developing situations which are dependent upon lengths or other conditions of the crop to be treated and rotational speeds ofthe rotary members. More particularly, any one oftheforegoing embodiments may include an arrangementwherebysuch openings are switchablea position in the screen adjacentthe feed chain and a position in the screen remote from the feed chain.

Alternatively, the arrangement may also be switchableto provide such openings in positionsofthe screen adjacent and remote from the feed chain, respectively.

The arrangement in which the screen is cut away in a position adjacentthefeed chain to define a straw discharge opening in afixed manner, hasthefollow- ing advantages: The lower group of rotary threshing members may have the lower faces thereof disposed very close to the screen to form a narrowthreshing space therebetween. The threshing teeth apply a threshing action and a stirring action to straw and cut ears ofthe crop (ortailings) passing through this threshing space. Accordingly, a secondarythreshing treatmentforthetailings already starts in the threshing chamber, which markedly improve the threshing efficiency ofthe whole apparatus performing both threshing and separating functions.

The rotary shafts ofthe rotatablethreshing members may either be in barform, tubularform ortube containing bars (drive shafts) therein. In either case, the rotary shafts have a diameter (160-200 mm) much smallerthan a diameter (360-440 mm) of a threshing drum of a priorartthreshing apparatus.

The invention will now be described furtherwith reference to embodiments illustrated in the accompanying drawings. These embodiments do not in any way limit the scope of the invention. In the drawings; Fig. lisa schematic view in vertical section of a combine harvester having a threshing apparatus according to one embodiment ofthe present invention, Fig. 2 is an enlarged sectional view taken on lines ll-ll in Fig. 1, Fig.3 is a sectional viewtaken on line Ill-Ill in Fig. 2, Fig. 4 is a view in vertical section of a threshing apparatus according to another embodiment ofthe invention, Fig. 5 is a sectional viewtaken on line V-V in Fig. 4, Fig. 6 is a viewsimilarto Fig. 5and showing a modified construction, Fig. 7 is a view in vertical section of a threshing apparatus according to a further embodiment, Fig. 8 is a perspective view of rotary threshing members ofthethreshing apparatus shown in Fig. 7, Fig. 9 is a schematic view in vertical section of a combine harvester having a threshing apparatus according to a further embodiment ofthe invention, Fig. 10 is an enlarged sectional viewtaken on line X-X in Fig. 9, Fig. 11 is an enlarged sectional viewtaken on line Xl-Xl in Fig. 9, Figs. 12 to 14 are schematic sectional views showing the threshing apparatus of Figs. 9to 11 ? in section, Fig. 15 is a schematic view in vertical section of a combine harvester having a threshing apparatus according to a still further embodiment of the invention, Fig. 16 is an enlarged sectional view taken on line XVI-XVI in Fig. 15, and Fig. 17 is an enlarged sectional view taken on line XVII-XVII in Fig. 15.

Referring to Fig. 1, a combine harvester has a threshing apparatus including a crop feed chain 1 for feeding a reaped crop to a threshing chamber2 housing rotationablethreshing members 3 for threshing the crop. Waste straw resulting from a threshing treatment is transmitted outwardly ofthe threshing chamber2 by the crop feed chain 1. An endless rotary chain 4 is provided rearwardly of the threshing section to discharge the straw transmitted by the crop feed chain 1 outwardly ofthe apparatus. A separating section is provided belowthethreshing chamber 2, which selecting section comprises a straw walker 5 to receive treated crop from the threshing chamber 2 and a blower 6to supply selecting airflows.

Two screw conveyors 7 and 8 are provided at bottom portions of the selecting section. The screw conveyor 7 isfortransmitting clean grain received from the separating section outwardly ofthe apparatus, and thescrewconveyor8isforreturningtailings received from the selecting section to the threshing chamber 2 forfurthertreatment.

Thethreshing section is more particularly described with referenceto Figs. 2 and 3. A plurality of rotary shafts 9 are arranged parallel to one another and to a direction of movement of the crop as carried by the crop feed chain 1. Each rotary shaft carries secured thereto a pluralityof rotarythreshing members 3 having threshing teeth 10 formed of plate. Thus, the rotary member3 have rotational axes Pparallel to the direction of movement ofthe crop, and are also arranged side by side in a longitudinal direction ofthe crop and above a screen 11. Drive gears 52 are provided at one end of the group of rotary members 3 to rotate respective rotary shafts 9. Each adjacent pair ofthe drive gears 52 is in operative connection with a gear 53 whereby all the rotary members 3 are driven to rotate in the same direction as shown by arrows A. The crop is threshed by action of the rotating teeth 10 while being transmittiedthrough a space between the rotary members 3 and the screen 11, and materials resulting from the threshing treatment are allowed to fall from the screen 11 to the separating section.

Each adjacent pair of rotary members 3 as seen transversely ofthe direction of movement of the crop is at an interval Lwhich is slightly largerthan a sum of a radius of one ofthe rotary member 3 and a radius of one ofthe rotary shafts 9. Therefore, tip ends ofthe threshing teeth 10 of one rotary member3 on one rotary shaft 9 pass very close to another rotary shaft 9 and betweentwo adjacent rotary members3 on this latter rotary shaft 9, and the threshing teeth 10 ofthe rotary members 3 have mutually overlapping operating ranges in axial directions of the rotary members 3.

This construction is effective to minimize non-treating spaces S, or spaces where none ofthe threshing teeth 10 pass and which assume a generally triangular shape above the screen 11 as viewed in axial direction of the rotary members 3.

Another embodiment will be described next with reference to Figs. 1,4,5 and 6. As shown in Figs. 1 and 4, a threshing section comprises a feed chain 1 which transmits reaped crop in a sidelong posture into a threshing chamber 2 through a crop inlet opening 12.

The threshing chamber2 houses a plurality of rotary shafts 9 extending along a path ofthe crop advancing through the threshing chamber2 and having axes parallel to the direction of movement ofthe crop. Each ofthe rotary shafts 9 carries secured thereto a plurality of rotarythreshing members3 having plate-like threshing teeth 10. The rotary members 3 have mutuallytransversely overlapping addendum circles and are rotatable in a direction A to acttowards ears of the crop. The threshing section further includes a screen 11 to act as a sieve means defining the bottom ofthethreshing chamber 2.

There is provided a separating section below the threshing section. The separating section comprises oscillatable straw walkers 5 for receiving materials resulting from the threshing operation and falling through the screen 11 and for separating grain from tailings by means of oscillations thereof and airflows generated by a blower 6. The grain is transported outwardly of the apparatus by a gain screw 7 disposed at the bottom of the apparatus. The tailings are returned by a tailings screw 8 to the threshing chamber 2 forfurthertreatment.

As shown in Fig. 5, the threshing teeth 10 are fixed to the plurality ofrotaryshafts mounted inthethreshing chamber 2 to be parallel to one another. As seen, the the threshing teeth 10 are arranged at crossing points ofthe rotary shafts 9 and inclined imaginary straight lines extending downstream in the conveying direction Boy the feed chain 1 as they extend farther away from the feed chain 1. In otherwords,thethreshing teeth 10 are secured to the plurality of rotary shafts 9 such that in plan viewthe threshing teeth 10 are displaced in a stepwise manner in a direction downstream ofthe movement ofthe feed chain 1. A row of the threshing teeth 10 in the stepwise arrangement constitutes a threshing teeth group 3B, and a plurality of such groups 3B are provided in the direction of crop movement.

The reason for arranging the threshing teeth groups 3B in the stepwise manner is that, although the threshing teeth 10 rotate at a very high speed compared with a conveying speed ofthefeed chain 1, ittakes a little timeforthethreshing teeth 10 to apply a combing action from a foot portion to ears ofthe crop, and the foot portion advances in the direction Bduring this little time. The ears ofthe crop would tend to lag behind ifthe combing action were applied simply in the longitudinal direction of the crop. This embodiment permits the ears ofthe crop to advance slightly ahead ofthefoot portion at the beginning ofthe threshing treatment.

This embodiment may be modified as shown in Fig.

6 in which such threshing teeth groups 3B are provided only in several rows adjacent a crop inlet opening 12 to correct bends or deformations of the crop upon entrytothethreshing chamber 2.

This embodiment may be applied to a construction in which the threshing teeth groups 3B are arranged on two planes, one above and the other below a path of crop transmission, and to a threshing apparatus in which crop is fed upwardly of rotary members 3.

According to the above construction, the crop entering the threshing chamber2 in a posture not optimal to threshing treatment is corrected into a posture optimal to threshing treatment by the threshing teeth 10 ofthe rotary members 3 rotating at a very high speed compared with the speed ofthe feed chain 1, which threshing teeth 10 act to combthrough the crop from adjacent the feed chain 1 away from the feed chain 1 and stretch the crop towards the ears.

This is effective to reduce unnecessary rubbing action ofthethreshing teeth 10 being applied to the crop. As a result, development of straw in thethreshing chamber 2, entwining of the crop around the rotary shafts 9 and other inconveniences are eliminated and the efficiency of the whole threshing apparatus is improved.

Afurther embodiment will be described next with reference to Figs. 1,7 and 8. This embodiment comprises a threshing chamber 2 whose bottom wall is defined by a flat screen 11. The threshing chamber 2 houses a plurality of plate-like rotary members 3 having threshing teeth 10 rotatable towards ears of reaped crop to apply a threshing action to the ears.

These rotary members 3 are arranged cn two planes, one above and the other below a path of movement of the ears, and each plane includes the rotary members 3 arranged both in a longitudinal direction of the crop and in a direction of movement ofthe crop. The threshing teeth 10 of two vertically opposed rotary members 3 have mutually overlapping addendum circles as seen in the direction of movement ofthe crop.

An oscillatable straw walkerS is disposed belowthe screen 11 to receive materialsfallingfromthe screen 11 and materials discharged togetherwith straw from a terminal end ofthethreshing chamber 2 and to separate the materials while transmitting the same in the direction of movement of the crop. There is provided a blower6for blowing air flows towards the strawwalker 5to assist in the selecting action thereof.

Grain is then collected ata grain port while a mixture of grain and straw, ortailings, is collected at a tailings port. Straw and other wastes are discharged by way of a waste port, and fine straw is drawn out ofthe apparatus by a transverse flow fan.

The rotary members 3 are mounted on hexagonal rotary shafts 9 to be rotatable in unison therewith.

These rotary shafts 9 are arranged above and below the path of movement of the crop ears and extend parallel to one another in the direction of the path. The rotary shafts 9 on each plane are interconnected by a drive chain. Spacers 13 are provided on boss portions ofthe rotary members3to determine intervals between adjacent rotary members 3.

The threshing apparatus according to this embodi mentmaybeinstalled on a combine or other harvester. Specific constructions of the rotary members 3 having the threshing teeth and of support means thereforare variable in many ways. For example, a pair of rotary members 3 vertically opposed to each other across the path of movement of the crop ears may be arranged such that the threshing teeth 10 ofthetwo rotary members 3 applythe threshing action to the crop with different timing.

Further, thethreshing teeth 10 may be inclined relative to the rotational axis thereofto apply a combing and stretching action to the crop.

The above construction has the following functional effect: Tip ends of the threshing teeth are located on both opposite sides of the crop ears which are introduced in a state having some thickness as viewed in the direction of movementthereof, and the rotating speed ofthe rotary members is determined so as to render a peripheral speed ofthetip ends ofthe threshing teeth optimal for the threshing treatment, whereby none ofthe crop ears are left unthreshed.

Moreover, although the rotary members are disposed at both sides of the crop ear path, the threshing apparatus may be made compact by providing the rotary members having a small diameter.

Referring to Figs. 9 to 14, the embodiment shown therein comprises a plurality of rotarythreshing members arranged on two planes, one above the other, but its characterizing feature resides in a screen disposed below the rotary members, and in particular in an opening or openings defined in the screen for discharging waste such as straw, chaff and other foreign matters. The rotary members on each plane carrythreshing teeth having a mutual positional relationship as in the first embodiment, as shown, but it is of course possible to arrange the threshing teeth as in the second embodiment.

The waste discharging opening or openings will now be described with reference to Figs. 14. Spaces S1 and S2 are provided between adjacent rotary shafts 9 arranged side by side in a longitudinal direction of the crop and between the rotary shafts 9 and a side wall 2a ofthethreshing chamber 2, respectively, to permit materials resulting from a threshing treatment to fall therethrough. A separating screen 11 is provided belowthe rotary shafts 9, which screen 11 defines waste discharge openings 21 and 22 at positions adjacent a threshing opening 20 and remote therefrom, respectively, each of the openings 21 and 22 extending in a direction of movement ofthe crop.

Two meshed lid members 23 and 24 are attached to the screen 11 to be vertically oscillatableto open and close the waste discharge openings 21 and 22, respectively. These lid members 23 and 24 are operable bytwo handless or manipulating means 25 and 26 provided outwardly ofthe apparatus, respectively. The materials resulting from the threshing treatmentfall on to the screen 11 and are separated into grain and straw, the grain being discharged through the screen 11 into a separating section D therebelow and the straw being discharged by way of the waste discharge openings 21 and 22 into the separating section D. This construction permits grain and large straw to be delivered dividedly into a portion ofthe separating section D adjacent the threshing opening and a portion ofthe separating section D remote therefrom by opening and closing the waste discharge openings 21 and 22.The construction is also effective to promptly deliver the materials resulting from the threshing treatment into the separating section Dwithout allowing the materials to remain on the screen 11 for a long time.

More particularly, as shown in Fig. when threshing short crop with ears thereof located adjacent the threshing opening 20, the waste discharge opening 21 adjacent the threshing opening 20 is closed and the waste discharge opening 22 remote therefrom is opened. Then, grain falls chiefly on to the portion ofthe screen 11 adjacent the threshing opening 20 and falls therefrom to the portion ofthe separating section Dadjacentthethreshing opening 20.On the other hand, large straw resulting from the threshing treatment and tending to remain among the rotary shafts 9 is transferred to a portion ofthe threshing chamber remote from the threshing opening 20 by action of threshing teeth 10, and falls through the space between the rotary shafts 9 and the side wall 2a and through the waste discharge opening 22 remote from the threshing opening 20 into a portion of the separating section D remote from the threshing opening 20.

As shown in Fig. 13,whenthrehsing long crop with ears thereof located remote from the threshing opening 20, the waste discharge opening 21 adjacent the threshing opening 20 is opened and the other waste discharge opening 22 is closed. Then, grain falls cheifly on to the portion ofthe screen 11 remote from the threshing opening 20 and falls therefrom to the portion ofthe separating section D remote from the threshing opening 20. Large straw which falls through the space between the rotary shafts 9 and the side wall 2a is transferred on the screen 11 towards the threshing opening 20 by the threshing teeth 10 on the lower rotary shafts rotating towards theth reshing opening 20 above the screen 11.The straw then falls through the waste discharge opening 21 adjacentthe threshing opening 20 to the portion of the separating section Dadjacent the threshing opening 20.

As shown in Fig. .14, when treating crop easy to thresh, both ofthe waste discharge openings 21 and 22areopened regardlessofcroplength.Then,not only straw falling through the space between the rotary sahfts 9 and the side wall 2a but also grain falling thereabouts is allowed to fall to the separating section Dthrough the waste discharge opening 22 remote from the threshing opening 20 without being transferred towards the threshing opening 20, and grain falling on to the screen 11 adjacentthethreshing opening 20 is allowed to fall to the separating section Dthrough the waste discharge opening 21 adjacent thethreshingopening 20withoutremainingonthe screen 11.

As shown in Fig. this embodiment has a threshing teeth arrangement as in the embodiment of Fig. 3, and therefore means 16forcombing and stretching the crop is provided as shown in Figs. 9 and 10 in order to advance the ears ofthe crop in pace with its foot portion. This means 16 comprises crop combing and stretching blades 16a driven by an endless chain to move in an upright projecting posture from adjacent the threshing opening 20 towards the opposite side along a crop inlet opening 12.

The waste discharge openings 21 and 22 may be defined by meshes ofthe screen 11 large than meshes in the intermediate portion ofthescreen 11.

The lid members 23 and 24 may be modified to be the sliding type or may comprise plate plates. Further, the lid members 23 and 24 may be arranged selectively operabie by a single opening and closing means.

Thetwowaste discharge openings 21 and 22 may be arranged to be alternatively opened and closed by modifying the screen 11 to be movable towards and awayfrom the threshing opening 20.

Finally, the embodiment of Figs. 15 to 17 will be described hereInafter. This embodiment, again, com- prises rotarythreshing members arranged on two planes, one above the other, between which crop is passed to undergo a threshing treatment This embodiment is different from the embodiment of Figs.

9to 14 in thattip ends ofthreshing teeth are arranged closer to a screen and a straw treating space is defined between the threshing teeth and the screen and that a portion ofthe screen adjacent a feed chain is cut away to de,ine awaste discharge opening. Thatportion of the screen adjacent a crop in let opening may or may not be çus away.

According to this construction, separated and half threshed ears, straw and the like are subjected to a threshing action and a violent stirring action ofthe teeth ofthe lower rotary members while advancing towards the waste discharge opening. This stirring action too promotes threshing of the ears, and only strawfalls byway ofthewaste discharge opening while grain falls through meshes ofthe screen on to an oscillatable separating walker.It is to be noted that only large straw advances between the upper and lower rotary members to reach an extreme end ofthe threshing chamber, makea U-turnandfallontothe screen since the rotary shafts and threshing teeth on both upper and lower planes are arranged close and compact. Small straw and grain, on the other hand, pass th rough the threshing teeth and fall directly on to the screen. Therefore, the grain and small straw fall through the meshes of the screen on to the separating walker before the large straw reaches a certain portion ofthe screen.This eliminates the possiblility of the region between the lower rotary members and the screen becoming clogged by an excessive amount of straw and others.

This construction will be described more particularlywith reference to Figs. 15 to 17.Athreshing section shown comprises a plurality of rotary threshing members 3 having addendum circles mutually overlapping vertically and horizontally, and a flat screen 11 defining a bottom ofathreshing chamber2 and disposed adjacent the lower rotary members 3 to act as sieve means. The screen 11 defines an elongate discharge opening 21 along an endthereofadjacenta feed chain 1 the opening 21 stopping short of a crop inlet ofthe threshing chamber 2.

The threshing apparatus further comprises an oscillatabie strawwaiker 5 belowthethreshing section to receive grain and small strawfalling through the screen 11 and to separate outthe grain by means of oscil latioils thereof and separating air flows generated by a blower 6, the grain thus separated being transported out of the apparatus by a conveyor screw7 disposed in the bottom ofthe apparatus.

There is also provided a transverse flow fan 39 to draw and discharge floating waste matters by way of a waste discharge port 38.

A mode ofthreshing operation in the threshing section will particularly be described next.

Reaped crop is held and carried in a sidelong posturebythefeedchain 1 into the threshing chamber 2, where the crop undergoes athreshingtreatment in a threshing space Cbetween the upper and lower groups of rotarythreshing mebers3,thethreshing action being imparted evenly from above and below.

Of materials separated from stalks, grain and relative ly small strawfall through the lower rotary members 3 on to the screen 11 and then pass therethrough, and relatively large straw is transferred by the upper and lower rotary members 3 towards an end ofthe chamber ber 2 opposed to ears ofthe crop, and advances round the lower rotary members 3 atihe righthand end and on to the screen 11.

The materials resulting from the threshing treatment are stirred on the screen 11 by the lower rotary members 3. Clean grain pass through he screen 11 while unclean grain is cleaned by the stirring action and thereafter pass through the screen 11. Since the lower rotary members 3 are rotating towards the feed chain 1 in opposed relating to the screen i lIthe entire materials resulting from the threshing treatment are advanced towards the feed chain 1. During the movement grain and other small materials pass through the screen 11 while large straw unable to pass the screen are discharged from the discharge opening 21.

Thus, the lower rotary members 3 actto thresh the crop in the threshing space Candatthesametimestir, advance and discharge the resulting materials on the screen 11.

Apartfrom the screen 11, the sieve means may comprise a concave including bars arranged parallel to one another at small intervals, or anotherform of sieve means consisting of fixed threshing teeth projecting upwardly and arranged at equal intervals.

The discharge opening defined at the end ofthe sieve means may extend over an entire length of the threshing chamber2 in a direction of movement ofthe crop.

Claims (6)

1. Athreshing apparatus comprising a plurality of rotary members each having a plurality of threshing teeth, wherein said rotary members are rotatable on parallel axes extending in a direction of movement of the reaped crop, said reaped crop being placed in a substantially straight posture in a direction substantially normal to said axes when in contact with said rotary members, and said threshing teeth of adjacent rotary members have addendum circles overlapping one another in a direction parallel to said axes.

2. Athreshing apparatus as claimed in claim 1, wherein at least those of said threshing teeth of said rotary members adjacent a crop feed opening are inclined in plan viewsuch thatsaidteeth closertothe ears of said crop are progressively downstream in said direction of movement of the reaped crop.

3. Athreshing apparatus as claimed in claim 7, wherein said rotary members are disposed both above and below a path of crop ears and said threshing teeth of said rotary members opposed to one another across said path have addendum circles overlapping one another in said direction of movement ofthe reaped crop.

4. Athreshing apparatus as claimed in claim 1,2, or3, further comprising a screen disposed below said rotary members, said screen being switchable between a state in which said screen defines waste discharge openings in positions adjacent and remote from a crop feed chain, respectively, and a state in which said screen defines a waste discharge opening at one of said positions adjacentto and remote from said crop feed chain.

5. Athreshing apparatus as claimed in claim 1,2 or 3, further comprising a screen disposed below said rotary members, said rotary members being all rotatable towards said crop ears in a path of said crop, and said screen defining a waste discharge opening adjacent the crop feed chains.

6. Athreshing apparatus substantially as hereinbefore described with reference to Figures 1 to 3, or Figures 4to 6, or Figures 7 and 8, or Figures 9to 14, or Figures 15to 17 oftheaccompanying drawings.