GB2088686A - Threshing machine - Google Patents

Abstract

A threshing machine for standing crops, particularly rice comprises a catcher casing (1) at the front of which a rotary thresher (2) cooperates with a counter-board (4). The beaters (5) on the thresher (2) comprise outwardly facing brushes (19) for pressing the heads (6) of cereal (16) against the counter-board and pulling the grains off of the heads (6), the brushes (19) comprising resilient bunches mounted on rigid backing members. The beaters may be mounted on rotors or on moving belts. <IMAGE>

Description

SPECIFICATION Threshing machine for standing cereal crops The present invention relates to threshing machines for standing cereal crops, especially but not exclusively for harvesting rice, of the kind comprising a casing installed on a wheeled vehicle having a rotating threshing wheel with beaters acting against a counterboard.

Currently, about two thirds of the world's population feeds mainly on rice. Almost everywhere, this cereal is harvested by cutting the stalks at the base, by hand using sickles, which is a toilsome fastidious operation, which takes up a lot of time and is inefficient.

In some modern paddy fields, it is known to use combine harvester type machines with caterpillar tracks. However this type of machine, apart from the fact that it involves cutting the stalks, can only be used in modern large acreage cultivations which are well equipped, and moreover is liable to bog down in the totally sodden terrain of a paddy field.

In any case a significant proportion of the grain is lost on the ground and water of the paddy fields during the operation of cutting the stalks because of the fragility of the panicles or heads of rice; in addition the operating conditions can be very different depending on the ripeness of the grains, the plant varieties, the height of the plants, the ground conditions, the humidity and so on; this necessiitates means for regulating the thresher.

Thus, to avoid severing the stalks, the beaters must not be too close to the counter-board, but must not be too far away from it either, to ensure that all the heads are threshed.

The object of the present invention is to provide a threshing machine of the kind referred to which is convenient to use and of reduced size, which does not involve cutting the stalks and avoids disadvantages of the present processes used, while giving a high yield by harvesting substantially all the cereal grains in a wide variety of working conditions.

To this end the present invention provides a threshing machine for threshing standing cereal crops, comprising a catcher casing for collecting the grains, rotary threshing means extending across the open front of the catcher casing and a counter-board cooperating with said threshing means, said threshing means including elongate beaters for engaging heads of standing cereal and pressing them against said counter-board, characterised in that said beaters comprise outwardly facing brushes for pressing said heads of cereal against said counter-board and pulling the grains off the heads, said brushes comprising resilient bunches mounted on rigid backing members.

The thresher is preferably mounted on the front of the machine.

With these arrangements the panicles can be shelled without being cut off the stalk and especially without striking the panicles in such a way as would scatter the grains of rice. The brushes comb and shell the panicles within the housing so that almost all the grains are harvested In an embodiment of the invention, the speed of the threshing machine over the ground is between 1 and 3 km an hour, preferably 1,8 km/h so that a head 25 cm long will stay 0,5 sec in the thresher.

The distance between successive beaters on the threshing wheel is less than the length of the heads above the contact position, for example about 25 cm, and is thus always in contact with at least one beater during its passage through the thresher.

The threshing wheel rotates at a speed between 50 and 700 rpm in the preferred embodiment; preferably the wheel has eight beaters and rotates at 100 to 1 25 rpm, so that typically a head is combed by 6 beaters while inside the thresher.

Advantageously said rotary threshing means and said counter-board are mounted for movement together relative to said catcher casing about hinge means, the catching edge of said counter board remaining horizontal. This enables the height of contact with the rice, and the angle to which the rice is bent to be regulated. In this context, an angle too acute will lead to the plants being severed or uprooted when it is between the beaters and the counter-board.

Other features and advantages of the invention will appear from the following description, given by way of non limitative example with reference to the accompanying drawings in which: Figure 1 is a diagrammatic side elevation of a machine in accordance with the invention; Figure 2 is a view in more detail of the thresher of the machine of Fig. 1; Figure 3 is a front view of the thresher of Fig. 2; Figure 4 is a top view, partly in section of a detail of the thresher of Fig. 2; Figure 5 illustrates the different phases of threshing standing rice in use of the machine of Fig. 1; Figures 6 and 7 show two alternative embodiments of the thresher of Fig. 2; Figure 8shows means for lifting flattened heads which may be used in the machine of Fig. 1;; Figure 9 shows an accessory for preventing heads being run over by the vehicle wheels, and which may be used in the machine of Fig. 1.

Figures 10 and 11 are diagrammatic views of a modified aniimal drawn embodiment of the invention; Figure 12 is a diagrammatic view of a motor driven embodiment of the invention for use by an operator on foot; Figures 13 and 14 are diagrammatic views of threshing machines in accordance with the invention drawn by tractors; Figure 15 is a detail view of an alternative elastic regulating system for a counter-board in the thresher of Fig. 2; and Figure 16 is a plan view of another thresher for use in a machine in accordance with the invention.

The machine shown diagrammatically in Fig. 1 comprises a metal casing 1 which is open at the front and top and is intended to receive grains, in this case grains of rice, separated from their stalks by threshing, which is achieved by a thresher device 2 mounted on the front (in the direction of movement) of the machine 1. This device 2 comprises a threshing wheel 3 disposed suitably above a counter-board 4 solid with the casing 1, in such a way as to obtain the optimum threshing. As will be seen in more detail in the later Figures of the drawings, the threshing wheel comprises paddles or beaters 5 which are designed to beat the rice by combing it rather than striking, and engage the grains carried in the heads 6, shown very diagrammatically, growing in the ground 7.At its rear, the casing 1 comprises a system 8 for conveying the grains, a device 9 for guiding the grains to a reservoir 10 for stocking the grain, shown in the form of a bin carried on a chassis 11 mounted on wheels 1 2 and solid with or driven by a wheeled vehicle (not shown). The casing 1 is attached to the chassis 11 by upper connecting bars 13, which may be regulatable and by a lower system of electrical or hydraulic jacks which support and enable regulation of the height of the casing above the ground. On the front edge of the machine is a separator system 1 5 for spreading the heads 6 sideways to minimize the number of heads run over by the wheels.

Figs. 2 to 4 show the thresher in more detail, and use the same numbers to identify similar parts.

The threshing wheel 3 is mounted on a horizontal shaft 1 6 and extends transverse to the direction of movement of the machine; the wheel 3 is driven by a transmission which includes a pulley 17, adapted to suit the different types of machine and means of propulsion which may be used, as described below. At each end, and in the middle, the threshing wheel 3 comprises a set of eight spokes 18, spaced equally at 45 , and at the outer ends of which eight beaters 5 are bolted. Each beater 5 comprises a brush 1 9 having outwardly facing bristles fixed to a backing 181 (see Fig. 2). The bristles are preferably formed of bunches of resilient vegetable or plastics fibres fixed in serried ranks.

The brushes extend across the whole width of the thresher 2, and are designed to comb the heads 6 so as to pull of the grains without striking the heads between two hard edges.

Moreover, in an alternative embodiment, the backings 18, of the brushes 1 9 can be fixed to the angle iron spokes 1 8 by sliders enabling the wear of the brushes to be compensated by adjusting the positions of the backings outwards.

By way of non limitative example, the threshing wheel 3 may be Im to 1,50m wide and have eight beaters 5 spaced apart circumferentially by a distance less than or equal to the length of the heads of rice to be threshed, for example 25cm. The speed of the machine over the ground is between 1 and 3km/h, in this example 1,8km/h so that a head 25 cm long will remain 0,5 secs in the thresher, always in contact with at least one of the brushes 1 9. The wheel 3 rotates at a speed between 100 and 500 rpm; in this example it rotates at 1 70 rpm, and a 25 cm long head of rice is stroked six times by the brushes 1 9 while it is inside the thresher.

The counter-board 4, which is mounted at the front lower edge of the casing 1 beneath the threshing wheel 1 3 comprises a rigid flat metal plate 21 extending over the whole width of the threshing wheel and is pivoted at its front edge on horizontal hinges 22. The plate 21 is maintained in a position tangential to the movement 23 of the outer edges of the brushes 1 9 by means of compression springs 24 of stiffness suitable for the particular plant varieties to be threshed, the springs 24 being mounted between the plate 21 and the floor of the casing 1, or outside the casing 1, so that the counter-board presents the desired resilience to the heads 6 pressed against it by the brushes 1 9. At its rear edge, the counterboard 4 comprises a bellows 25 closing off the space between the plate 21 and the floor of the casing 1, so as to avoid this space filling up with harvested grains of rice.

The front edge of the counter-board 4 presents a blunt edge 27 for catching the stalks of the rice as the machine advances. The shape of the catching edge 27 is rounded so that the stalks of the heads 6 slide over it and bend without breaking. The separating systems 1 5 for spreading the heads apart sideways are disposed at each end of the catching edge.

The means fixing the threshing wheel over the counter-board 4 and the casing 1 will now be described, these means also enabling the position of the threshing wheel to be regulated relative to the position and angle of the counter-board.

At the ends of its shaft 1 6, the threshing wheel 3 is carried on two elongate flat supports 28 which comprise longitudinal openings 29 cooperating with bolts 30 and 31 to form longitudinal sliders, the bolts 30 and 31 connecting the supports 28 to fixed side members 32 which are solid with the casing 1, being welded for example to a rib 33 reinforcing the casing 1, the counter-board 4 extending between the side members 32. As shown in Fig. 2, the side members 32 project upwards and forwards relative to the floor of the casing 1. Each side member 32 also has an arcuate opening 34 cooperating with the bolt 31 to form an arcuate slider, the bolt 30 engaging in a fitting hole (not shown) in the upper end of the side member 32.The threshing wheel 3 is adjusted to its operating position relative to the counter-board 4, as shown in Fig. 2, by use of the sliders and then secured in position by tightening the bolts 30 and 31. The adjustment can be made simultaneously or separately in two ways, either longitudinally of the supports 28 over a stroke defined by the slots 29, or forwards and backwards of the machine, over a stroke defined by the slots 34.

In general, as shown in Fig. 2, the shaft 16 of the threshing wheel is adjusted so as to be disposed in front of the catching edge 27 of the counter-board 4, so that the brushes 1 9 contact the heads 6 first and pull them onto the catching edge, whose height has been regulated as mentioned above.

In accordance with the invention, at the rear of the casing 1 is disposed a system 8 for conveying to one side the grains projected by the beaters 5 to the rear wall of the casing 1, which acts as a foot for collecting the grain.

In this example the conveyor 8 is an Archimedes screw, also shown in plan view in Fig.

4, driven by a belt 35 having a tensioner 36 and running off a pulley(not shown) on the shaft 16. A cover 37 in thin sheet steel or plastics material stops the grains being thrown upwards out of the chassis I and its front edge has a deflector to direct the grains downwards and rearwards. On one side of the casing 1 is disposed an elevator device 38, comprising rotating paddles 39 driven by a belt 40 off the shaft 1 6 and taking grains conveyed by the conveyor 8 to this side of the boot in the casing 1. The paddle 39 propels the grains up a guide device 9 in the form of ducting to a double outlet spout 41 (see Fig. 1) disposed above the bin 1 0. In this system, a fan (not shown) may also be provided to blow away chaff.

The operation of the machine will now be described with reference to Fig. 5. When the machine reaches the heads 6 (phase 1), the blunt catcher edge 27 engages the stalks about 1 5 cm beneath the panicles, and the threshing wheel rotates in a direction such that the beaters 5 at the bottom move rearwards faster than the forward speed of the machine over the ground, so that they push the heads 6 against the catching edge 4. In the next phase (phase II), the beaters 5 press the stalks resiliently against the counter-board 4 and the brushes 1 9 comb the heads 6, pulling the grains off and propelling them rearwards. Lastly (phase Ill) the stripped stalks 42 are pulled forward out of the casing 1 by the advance of the machine. The detached grains propelled into the casing are then collected and conveyed as described above.

In conformity with the invention, different types of thresher can be advantageously used, as a function of the height and resistance of the heads, as shown in Figs. 6 and 7 for example.

In the thresher of Fig. 6, the beaters 45 move above a counter-board 4 around two drums 43 on a band or belts 44 in the direction shown by the arrow. Such a device is used when it is desired to engage the heads well in front of the catching edge 27 or when the forward speed of the machine over the ground is very high. The device can also comprise means (not shown) for regulating the height of the front drum.

The thresher of Fig. 7. comprises three drums 47, around which moves a band 48 with beaters 49 in the direction shown by the arrow 50. This system is suitable for very tall plants which have to be pulled down efficiently against the counter-board 4.

Fig. 8 shows the front part of the casing 1 in a machine in accordance with the invention, in the leading edge 27 of which is mounted a pivoted device 51 for lifting the heads 6 when these have been flattened. The device 51 is controlled by means of a suitable mechanism 52 connected for example to a lever 53 fixed to the casing 1.

Fig. 9 shows in plan view the separator system 1 5 for spreading the heads 6 sideway as the machine advances in the direction of the arrow 54, to avoid running over heads with the vehicle's wheels.

Referring now to Figs. 10 to 14, different modes of mechanical or animal propulsion of the machine in accordance with the invention, and of drive for the thresher, will now be described.

Fig. 10 is a top view of a side-positioned machine in accordance with the invention, for animal propulsion, for example by one or two horses. The casing 1, mounted on wheels 55, is solid with a chassis 56 moved by a suitable draught 57, shown diagrammatically, or one horse (not shown) between harness shafts 58, 59 or by a pair between harness shafts 58, 59, 60. The thresher 2 is driven by a roller or detachable link chain 61 with power take off from the rotating axle of wheels 55. In the drawing the broken lines correspond to the pair draught. A single draught machine may have a thresher of 1,30 m wide, and a double draught machine 2,50 m.

Fig. 11 shows the case of a machine in accordance with the invention which is oxdrawn in a paddy field, the harness comprising a yoke 62, and the thresher drive being similar to Fig. 1 0. The machine is again side positioned. The machine may be carried on runners instead of wheels, with an accessory motor mounted on the casing 1 and driving the thresher through a chain or belt drive, the thresher speed then being independent of the speed of the animals. The thresher drive could also be obtained from a hydraulic transmission including a hydraulic pump (not shown) which enables the speed of rotation of the thresher to be controlled over a range from 50 to 700 rpm.

Fig. 1 2 shows an embodiment which is propelled by a motocultivator 63, that is to say a motor driven two wheeled vehicle, steered by an operator on foot. The chassis 64 of the motor cultivator supports the casing 1 in front and the threshing wheel 3 is driven by a belt drive 65 running on the pulley 1 7 of the thresher and on a pulley 66 on the power take off of the moto-cultivator. In this embodiment, the thresher can be 70 to 80 cm wide.

A tensioning device can be provided to take up play in the position of the threshing wheel.

Figs. 1 3 and 14 illustrate embodiments of the invention in which the thresher is front mounted or side mounted on an agricultural tractor 68.

In the former case (Fig. 1 3) the threshing wheel 3 is driven by the power take off 69 of the tractor engine through pulleys 70, 71 and belt 72 and a transmission shaft 73 with a sliding universal joint 74, shown diagrammatically. A hydraulic transmission (not shown) would be a feasible alternative. In this embodiment the thresher can be 1 to 3 metres wide.

In the latter case (Fig. 14) the threshing wheel 3 is driven from the power take off by a similar system 70, 71, 72 to that of Fig. 13, with additional pulleys and belts (75, 76, 77) or shafts and angle joints, as is the Archimedes screw 8.

It is clear that the threshing machine described may be coupled to and driven by a tractor or made automobile without departing from the scope of the invention.

Fig. 1 5 shows an alternative system for obtaining the resilience of the counter-board 4. In this system, a compression or tension spring is hooked between a wall of the casing 1 and the rear of the plate 21 of the counterboard 4 and can be regulated by a screw 80.

In the machine in accordance with the invention, the plate 21 of the counter-board 4 may alternatively be rough or patterned and may be curved round the thresher wheel, for more difficult threshing where it is desired to increase the effectiveness of combing and retaining the grains.

In the embodiment shown in Fig. 1 6 the two fixed side members 32 associated with the supports 28 of the threshing wheel 3 are fixed to the casing 1 through the rib 33, the sub-assembly of the rib 33, counter-board 4 and threshing wheel 3 being pivotable on a hinge 81 so that the threshing wheel and counter-board can be brought together to different heights off the ground by altering the position of the rib 33 about the hinge 81.

This enables the height of the catching edge 27 to be adjusted to the height of the plants, and especially the height of the heads. The displacement and locking of the sub-assembly in the desired relative position can be ensured by a suitable means such as a lever 82, rack and pinion, toothed sector, endless screw, jack. The operator thus has two adjustments available (angular movement of the thresher sub-assembly relative to the casing 1, and displacement of the threshing wheel 3 relative to the counter-board 4 by the sliders 29 and 34). This double adjustment gives a better adaptation of the catching edge 27 to the crops.

Claims (11)

1. A threshing machine for threshing standing cereal crops, comprising a catcher casing for collecting the grains, rotary threshing means extending across the open front of the catcher casing and a counter-board cooperating with said threshing means, said threshing means including elongate beaters for engaging heads of standing cereal and pressing them against said counter-board, characterised in that said beaters comprise outwardly facing brushes for pressing said heads of cereal against said counter-board and pulling the grains off the heads, said brushes comprising resilient bunches mounted on rigid backing members.

2. A threshing machine as claimed in claim 1 characterised in that said beaters are spaced circumferentially by a distance less than or equal to the length of the heads of rice, said rotary threshing means being arranged to run at a speed such that at least two of said beaters engage each head of cereal in said threshing means.

3. A threshing machine as claimed in claim 1 or 2 characterised in that said bunches comprise resilient vegetable or plastics bristles disposed in closely adjacent positions across the whole width of the catcher casing.

4. A threshing machine as claimed in claim 1, 2 or 3 characterised in that said rotary threshing means and said counterboard are mounted for movement together relative to said catcher casing about hinge means, the catching edge of said counterboard remaining horizontal.

5. A threshing machine as claimed in claim 1, 2 or 3 characterised in that said rotary threshing means extends in front of the catching edge of said counter-board whereby said beaters engage the cereal heads before said catching edge and draw them onto the counter-board.

6. A threshing machine as claimed in claim 1, 2 or 3 characterised in that said rotary threshing means includes regulating means for regulating the positions of said beaters relative to said counter-board.

7. A threshing machine as claimed in claim 1, 3 or 6 characterised in that said counter-board comprises a plate hinged adjacent its leading edge and resilient means urging said plate towards said rotary threshing means.

8. A threshing machine as claimed in claim 1, 3 or 6 characterised in that said catching edge of said counter-board is blunt, whereby to present a sliding surface for engaging the stalks of the cereals.

9. A threshing machine as claimed in claim 1 characterised in that the machine is supported on a pair of wheels spaced laterally and for steering by an operator on foot, said rotary threshing means including a belt drive, with play in the position of said rotary threshing means and said counter-board being variable, and tensioning means for tensioning said belt drive, whereby to take up said play.

1 0. A threshing machine as claimed in claim 1 characterised in that the machine is mounted on the front of a motorised vehicle, and including shaft drive means for transmitting drive from the vehicle engine to said rotary threshing means.

11. A threshing machine as claimed in claim 1 characterised in that the machine is mounted at the side of a motorised vehicle, and including shaft drive means for transmitting drive from the vehicle to said rotary threshing means.

1 2. A threshing machine as claimed in claim 1 characterised in that the machine comprises wheels, means for hitching at least one animal to draw the machine, and loop drive means for transmitting drive from said wheels to said rotary threshing means.

1 3. A threshing machine as claimed in claim 1 characterised in that the machine includes means for hitching at least one animal to draw the machine and motor means for driving said rotary threshing machine.

1 4. A threshing machine as claimed in claim 1 characterised in that the machine includes a chassis and means for regulating the height of said catcher casing, said rotary threshing means and said counter-board relative to said chassis.

1 5. A threshing machine as claimed in claim 1 characterised in that the machine includes conveyor means disposed at the rear of said catcher casing for conveying grains towards one side of said catcher casing, and elevator means for transporting the grains from said one side to an outlet.