WO1992012619A1

WO1992012619A1 - Metering device for a sowing apparatus

Info

Publication number: WO1992012619A1
Application number: PCT/DK1992/000015
Authority: WO
Inventors: Finn Ulrik Hansen Jensen; Asger Schjellerup Olsen; Mathias Andersen
Original assignee: Kongskilde Maskinfabrik A/S
Priority date: 1991-01-22
Filing date: 1992-01-21
Publication date: 1992-08-06
Also published as: DK10291D0

Abstract

The metering device is for a sowing machine for metering granular material, particularly seed grain, comprising an elongate, funnel-shaped granulate compartment (4), bottom flaps (5) closing the granulate compartment (4) at the bottom, and which at one end are pivotally mounted on a common shaft (6) longitudinally positioned in relation to the granulate chamber and at the other end (13) form a seed slot together with a respective metering wheel (7), said metering wheels (7) being mounted on a common shaft (9) longitudinally positioned in relation to the granulate compartment (8) and each adapted to meter granular material to an outlet (11) from the metering device. The metering wheels are cellular wheels (7), and are adapted to be removed from the housing together with their shaft as a unit.

Description

METERING DEVICE FOR A SOWING APPARATUS

The present invention relates to a metering device for a sowing machine for metering granular material, particularly seed grain, comprising an elongate, funnel- shaped granulate compartment, bottom flaps closing the granulate compartment at the bottom, and which at one end are pivotally mounted on a common shaft longitudinally positioned in relation to the granulate chamber and at the other end form a seed slot together with a respective metering wheel, said metering wheels being mounted on a common shaft longitudinally positioned in relation to the granulate compartment and each adapted to meter granular material to an outlet from the metering device. Such a metering device is known for instance from FR 2,593,348-A3 and DK-C-33,401.

Furthermore, several sowing machines with metering devices of the above kind are available on the market. It is in all cases a question of sowing machines, in which the metering device is an integral part of the machine, and where the machine is a bigger unit with own wheels and a considerable width, which is only limited on account of the law requirements for road driving.

Within the agricultural sector such a sowing machine will be used for sowing many different kinds of crops and for the spreading of fertilizers. Depending on the type of material to be sown different demands are made on the metering wheels, as the size of the granulate varies very much, the size of peas being fairly big, the four sorts of cereals being middlesized, whereas for instance oilseed rape and mustard seed are very small. Normally, the same metering wheel cannot be used for t.ie sowing of all these crops.

To solve this problem it is known to use metering wheels in the shape of cam wheels divided into several parts with areas suited for sowing big seeds and areas suited for sowing small seeds, and, according requirements, only to run some of these areas.

Another way of solving this problem is to use so- called sowing fingers, which cover a part of a cam wheel, thus making it more suited for the sowing of smaller seeds.

It is furthermore known to adjust the bottom flaps in accordance with the size of the seed grains in such a way that the sowing slot between the metering wheel and the end of the bottom flap is widened or narrowed.

In WO 87/03166 a metering device is disclosed, in which metering wheels are placed with intervals on a long shaft outside the device, the shaft with the metering wheels being interchangeable for adaptation to the seed grains in question. Under the metering wheels there are no adjustable bottom flaps, but a fixed bottom.

The above sowing machines are provided with a granulate compartment in the shape of a fairly big housing, which is filled with seed grain at the beginning of the sowing operation.

A problem in connection with metering devices of the above type is the exactness of the sowing, to be understood as the amount sown per rotation of the metering wheels. This sowing exactness is depending on whether the metering device is being driven uphill or downhill or straight ahead, i.e. of the mutual position of the metering wheel and the bottom flap in relation to vertical in a plane transverse to the axis of rotation of the metering wheels. Furthermore, it has also turned out that the load of seed in the granulate compartment influences the sowing exactness.

The object of the invention is to provide a metering device which meters with exactness independent of the sloping of the ground and the seed load in the granulate compartment.

According to the invention this is obtained by means of a metering device, which difers from the known devices in that it comprises a small compact housing containing the granulate compartment, an inlet thereto for granulate and an air compartment with an inlet for compressed air, the outlets from the metering device being placed in the air compartment, whereby the compressed air during operation is conveying the metered material out through the outlets, that the bottom flaps and the metering wheels, respectively, are close together, that the metering wheels are cellular wheels, the cells of which are laterally confined by radial flanges on the cellular wheels, that the cellular wheels together with their shaft can be removed from the housing as a unit, the cell size of the cellular wheels being thus adaptable to whatever granular material to be metered, and in that the bottom flaps are preset in such a way that there is a clearance between the flanges of the cellular wheels and the bottom flaps.

The small compact housing occasions small dimensions, which makes it possible to make the shaft with the cellular wheels an easily removable unit. This makes it possible, without any problems, to exchange the cellular wheels in such a way that the size of the cells always corresponds to the size of the material to be metered. A suitable cell size and a minimum distance between the flanges of the cell wheels and the bottom flaps ensures that only material conveyed to a cell is metered. Thereby an exact metering is attained indenpendent of the sloping of the ground. Likewise, the importance of the grain load is reduced. Besides, the grain load is under all circumstances small on account of the small dimensions of the housing.

According to an embodiment of the invention the housing is longitudinaly divided into a first and a second part, which are detachably assembled, the first part comprising the bottom flaps and the outlets, and the second part comprising the inlets for granulate and compressed air, respectively, and the shaft with the cellular wheels is adapted to be removed transversely to the longitudinal direction of the housing. According to a further embodiment of the invention each end of the shaft with the cellular wheels is journalled in a flat element adapted to be lowered into and to fill out a recess in each of the end walls of the housing, and at least one element is provided with flanges extending over the edge of the recess and guiding the element in relation to this edge. Thereby it is made particularly simple to exchange the cellular wheels. In a further embodiment of the invention the second part comprises a curved shielding plate extending along and shielding part of the periphery of all the cellular wheels, a perforated plate forming a wall in the granulate compartment and facing the shielding plate over the whole of its length, and a guide plate in the air compartment forming together with the edge of the shielding plate facing the air compartment a first longitudinal slot and together with the outer wall of the housing a second longitudinal slot in such a way that the compressed air from the inlet is lead through the second slot towards the outlets, thereby creating a low pressure in the first slot by means of an ejector effect.

The metering device according to the invention should when used in a sowing machine currently be supplied with granulated material, as in the granulate compartment of the small housing there is not room for the amounts of granulated material needed to sow a whole field. The supply may take place from a hopper by means of a conveyance system. An example of such a conveyance system is given in EP-A-0 369,766. A metering device with the said second part of the housing described in the latter embodiment is suited for use in connection with such a conveyance system. By means of the guide plate it is ensured that the pressure in the air compartment at the perforated plate will not become too high, which would, should the occasion arise, result in a ruining of the function of the conveyance system.

The metering device according to the invention may, however, also be used in other connections than with the conveyance system mentioned in the said European patent application.

According to a further embodiment of the invention the second part of the housing comprises a perforated wall of the granular compartment, through which air may penetrate from the granular compartment to the surroundings. Furthermore, the second part may in another embodiment comprise an intermediate compartment between the air compartment and the granulate compartment, the perforated wall constituting a partition between the granulate compartment and the intermediate compartment, which has an outlet to the surroundings.

In connection with this embodiment pneumatic transportation of granulated material from a hopper to the metering device may be used, the conveyance of the metered material through the outlets only being dependent on the compressed air entering through the inlet to the air compartment. In the embodiment the used transport air may through the intermediate compartment and its outlet be conveyed through a hose to the ground in order to avoid inconvenience from dust.

According to a further embodiment the second part of the housing comprises a solid wall between the granulate compartment and the air compartment. By this embodiment no air of significance can flow between the air compartment and the granulate compartment, for which reason this embodiment is suited for being used in a sowing machine with mechanical conveyance of the granulated material from the hopper to the metering device. On account of the current re-filling of the granulate compartment the additional advantage attained is that the grain load, apart from being small, is essentially constant, the exactness of the metering being thus further improved.

The first and the second parts are preferably held together by means of snap-buckles to facilitate the exchange of the cellular wheels.

According to another embodiment some of the wheels may be blind wheels. Thereby, during the sowing socalled "fertilizer tracks" without any seed are provided in the field. Finally, the celluar wheels are according to an embodiment of the invention each generally symmetric around a centre plane perpendicular to the rotating shaft, a peripheral row of cells being arranged at each side of this centre plane, and the cells of the two tows being displaced by the length of half a cell in relation to each other. Thereby such pulsations in the metering, which are likely to occur in connection with cellular wheels with cells extending over the whole width of the wheel, are avoided. The invention will be described in detail in the following by means of embodiments with reference to the drawing, in which:

Fig. 1 is a sectional view of the metering device in a first embodiment of the invention,

Fig. 2 is a sectional view thorugh the second part of the housing of a metering device in a second embodiment.

Fig. 3 is a sectional view according to Fig. 2 in a third embodiment of the invention, and Fig. 4 is a sectional view, in which the upper part of the metering device has been cut along IVa-IVa in Fig. 1, and the bottom part has been cut along IVb-IVb apart from the cellular wheels, which for the sake of clarity have not been cut. The metering device shown in Figs. 1 and 4 comprises an upper part 1 and a bottom part 2. These to parts are assembled by means of snap-buckles 30, of which only one is shown. The bottom part comprises a funnel-shaped granulate compartment 4, which is at the bottom confined by a row of bottom flaps 5 mounted close together on a common shaft 6. On this shaft 6 an abutment member 33 is further provided for each bottom flap 5, said abutment member rotating with the shaft 6 on account of a pointed screw 34. The abutment member 33 serves as abutment, partly for a screw 35 serving as abutment for the bottom flap 5, partly for a spring 36 keeping the bottom flap 5 against its abutment. On account of the spring 36, the bottom flap 5 may allow the passage of for instance a stone, whereby damages may be avoided.

Over the bottom flaps 5 is placed a row of cellular wheels 7 also mounted close together, whereby each bottom flap corresponds to a cellular wheel. The cellular wheels 7 are mounted on a shaft 8 without any possibility of rotation in relation thereto, and the cellular wheels have flanges 9, which confine the outer diameter of the cellular wheels, and cells 10 between the flanges. Each cellular wheel 7 is divided along its vertical centre plane, and the cells 10 at both sides of the centre plane are displaced by the length of half a cell in relation to each other, as shown in Fig. 4. Preferably there will be 12 - 18 cellular wheels 7 in a metering device.

The bottom flaps 5 are by means of their pointed screws 34 fixedly set in relation to the flanges 9 of the cellular wheels so that a clearance is established between the flanges 9 and the ends 13 of the bottom flaps.

With a view to its placing and journalling in the metering device, the shaft 8 of the cellular wheels has at each end a ball bearing 37, seated in a rectangular plate member 38, which is fastened between an interior, downwards circular and upwards rectangular flange member 39 and an exterior shielding member 40. The rectangular plate members 38 correspond to recesses 41 in the end walls 42 of the metering device. The flange elements 39 and the shielding elements 40 extend out over the edge of the plate members 38, thereby serving as guides in relation to the edges of the recesses 41. This construction ensures that the cellular wheels 10 with their shaft 8 can be removed immediately from the bottom part of the metering device, when the upper part 1 is removed.

The bottom part 2 further comprises an element 32 with an outlet 11 for each cellular wheel 7. Each outlet 11 comprises, in the embodiment shown, a duct 46, the sidewalls 14 of which extend from somewhat above the outer end 13 of the bottom flap 5, where they follow the periphery of the cellular wheel 7, to a hose connection 12. The ducts 46 are closed upwards by a curved flange 31 of the sidewall of the bottom part 2 of the metering device.

The upper part 1, which is fastened to the bottom part 2 by the snap-buckles 30, contains an upper section of the granulate compartment 4 and an upper section of an air compartment 15. A curved shielding plate 16 shields a part of the perihery of the cellular wheels 7 and is at the edge, which is closest to the granulate chamber 4, connected with a perforated plate 17, the perforations 45 of which have such a size that air, but not granulated material to be metered, may pass. The perforated plate 17 constitutes a partition wall between the granulate compartment 4 and the air compartment 15. In the air compartment is a guide plate 18 guiding air from an inlet 19 to the air compartment 15 towards the outlets 11. The guide plate extends throughout the whole length of the metering device so far downwards that together with the shielding plate 16 it forms a first slot 20 and together with the wall 21 of the metering device a second slot 22.

Finally the upper part 1 has an inlet 23 for granulate to the granulate compartment 4. The inlets 19 og 23 may, as shown schematically, be connected to connections 43 and 44, respectively.

The metering device described above may be used in the sowing machine disclosed in EP-A-0 369 766. In that case granulated material will during operation be conveyed by means of compressed air into the granulate compartment 4 though the inlet 23. The conveying air will escape from the granulate compartment 4 through the perforated plate 17 to the air compartment 15. The cellular wheels will rotate as shown by the arrow 24 and meter the granulated material from the granulate compartment 4 to the duct 46 of their respective outlets 11. Compressed air will through the inlet

19 flow into the air comparment 15 to be led by the guide plate 18 through the slot 22 and towards the outlets 11. On account of an ejector effect the air, which penetrates from the granulate compartment 4 through the perforated plate 17, will be sucked along through the outlets. The air flow through the outlets 11 conveyes the metered material.

In Fig. 2 a second embodiment of the upper part 101 is shown which, like the embodiment according to Fig. 1, comprises the upper sections of the granulate compartment 4 and the air compartment 15, an inlet 19 to the air compartment and an inlet 23 to the granulate compartment. Furthermore, there is, like in the embodiment according to Fig. 1, a perforated plate 17 which constitutes a wall of the granular compartment 4 and is connected with the shielding plate 16. The edge thereof close to the air compartment 15 is however in this embodiment connected with a wall plate 25, whereby an intermediate compartment 26 without connection to the air compartment 15 is created. In the intermediate compartment 26 an outlet 27 for air is provided in the end wall of the device.

The metering device provided this embodiment of the upper part 101 may like the device according to the previously described embodiment be used in connection with a sowing machine according to EP-A-0 369 766.

The two air flows entering through the inlets 19 and 23, respectively, will in this embodiment not disturb one another, as the conveying air for the granulated material, after having penetrated through the perforated plate 17, passes through the intermediate compartment 26 and out through the outlet 27 of this chamber. The outlet 27 may be connected to a hose, which guides the outflowing air down towards the ground in order to prevent inconvenience from dust.

The air entering the air compartment 15 through the inlet 19 flows down to the outlets 11 conveying the metered material, which is by the metering wheels 7 conveyed out over the ends 13 of the bottom flaps 5 and into the ducts 46.

In Fig. 3 a further embodiment of the upper part 201 is shown. This embodiment is to a great extent similar to the embodiment of Fig. 2. In this case, however, the perforated plate 17 has been replaced by a solid wall 28. This embodiment is intended for use in connection with a sowing machine, in which the conveyance of granulated material from a storage hopper to the metering device is carried out by mechanical means, for instance a helical conveyor. In this case there will be no transport air to be guided away form the granulated compartment 4, for which reason a perforated wall is superfluous. Therefore, there is no need either for the intermediate compartment 26, shown in Fig. 2, with the outlet 27, and due to that there is not in this embodiment an element corresponding to the wall plate 25.

Irrespective of the embodiment of the upper part it is a common feature that the shaft 8 with the metering wheels 7 as well as the bearings of the shaft can be quickly and easily exchanged by opening the snap-buckles 30, after which the upper part can be lifted off. There is then free access to the shaft 8 with the cellular wheels 7, and the shaft may just be removed after the removal of the transmission elements at the ends of the shaft. Then another shaft 8 with other cellular wheels can be placed in the device in order to sow another kind of crop. The fixedly set bottom flaps 5 make an adjustment in connection with the exchange of the cellular wheels 7 superfluous.

Due to the fact that the various shafts 8 with cellular wheels 7 are small units which are easy to handle, it presents no problem to have a number of shafts with varying cellular wheels corrresponding to the various crops or fertilizers, and to exchange the shaft with the wheels according to need. Thereby it is attained, as previously said, that the exactness of the metering to a high degree is independent from conditions in the surroundings and from influences therefrom.

Claims

C L A I S

1. A metering device for a sowing machine for metering granular material, particularly seed grain, comprising an elongate, funnel-shaped granulate compartment (4), bottom flaps (5) closing the granulate compartment (4) at the bottom and which at one end are pivotally mounted on a common shaft (6) longitudinally positioned in relation to the granulate chamber and at the other end (13) form a seed slot together with a respective metering wheel (7), said metering wheels (7) being mounted on a common shaft (9) longitudinally positioned in relation to the granulate compartment (8) and each adapted to meter granular material to an outlet (11) from the metering device, c h a r a c t e r i z e d in that it comprises a small compact housing containing the granulate compartment (4), an inlet (23) thereto for granulate and an air compartment (15) with an inlet (19) for compressed air, the outlets (11) from the metering device being placed in the air compartment (15), whereby the compressed air during operation is conveying the metered material out through the outlets (11), that the bottom flaps (5) and the metering wheels (7), respectively, are close together, that the metering wheels are cellular wheels (7), the cells of which are laterally confined by radial flanges (9) on the cellular wheels (7), that the cellular wheels (7) together with their shaft (8) can be removed from the housing as a unit, the cell size of the cellular wheels being thus adaptable to whatever granular material to be metered, and in that the bottom flaps (5) are preset in such a way that there is a clearance between the flanges (9) of the cellular wheels (7) and the bottom flaps (5) .

2. A metering device according to claim 1, c h a r a c t e r i z e d in that the housing is longitudinaly divided into a first and a second part (1,2) which is detachably assembled, that the first part (2) comprises the bottom flaps (5) and the outlets (11), and the second part (1) comprises the inlets (23,19) for granulate and compressed air, respectively, and in that the shaft (8) with the cellular wheels (7) is adapted to be removed transversely to the longitudinal direction of the housing.

3. A metering device according to claim 2, c h a r a c t e r i z e d in that each end of the shaft (8) with the cellular wheels (7) is journalled in a flat element (38) adapted to be lowered into and to fill out a recess (41) in each of the end walls (42) of the housing, and in that at least one element (38) is provided with flanges (39,40) extending over the edge of the recess (41) and guiding the element (38) in relation to this edge.

4. A metering device according to claim 2 or 3, c h a r a c t e r i z e d in that the second part (1) comprises a curved shielding plate (16) extending along and shielding part of the periphery of all the cellular wheels (7), a perforated plate (17) forming a wall in the granulate compartment (4) and facing the shielding plate (16) over the whole of its length and a guide plate (18) in the air compartment (15) forming together with the edge of the shielding plate (16) facing the air compartment (15) a first longitudinal slot (20) and together with the outer wall (21) of the housing a second longitudinal slot (22) in such a way that the compressed air from the inlet (19) is lead through the second slot (22) towards the outlets (11), thereby creating a low pressure in the first slot (20) by means of an ejector effect.

5. A metering device according to claim 2 or 3, c h a r a c t e r i z e d in that the second part (101) comprises a perforated wall (17) of the granular compartment (4), through which air may penetrate from the granular compartment (4) to the surroundings.

6. A metering device according to claim 5, c h a r a c t e r i z e d in that the second part (101) comprises an intermediate compartment (26) between the air compartment (15) and the granulate compartment (4), that the perforated wall constitutes a partition between the granulate compartment (4) and the intermediate compartment (26), and in that the intermediate compartment (26) has an outlet (27) to the surroundings.

7. A metering device according to claim 2 or 3, c h a r a c t e r i z e d in that the second part (201) comprises a solid wall (28) between the granulate compartment (4) and the air compartment (15).

8. A metering device according to claims 2-7, c h a r a c t e r i z e d in that the first and the second parts (2,1) are held together by means of snap-buckles (30).

9. A metering device according to claims 1-8, c h a r a c t e r i z e d in that some of the cellular wheels (7) are blind wheels without cells.

10. A metering device according to claims 1-9, c h a r a c t e r i z e d in that the cellular wheels (7) have each a general symmetry plane perpendicular to their shaft (8) and that they have a peripheral row of cells (10) on each side of this symmetry plane, the cells (10) of the two rows being displaced by the length of half a cell in relation to each other.