DOSING DEVICE FOR GRANULAR MATERIAL AND DISTRIBUTOR WITH DOSING DEVICE

Description

[0001] The invention relates to a dosing device for granular material according to the preamble of patent claim 1 and a distribution machine according to the preamble of patent claim 15.

[0002] Such a distribution machine with a metering device is described in EP 3 146 828 B1. This distribution machine is used for spreading seeds and / or fertilizers and comprises a storage container for the granular

[0003] Goods such as seeds or fertilizers. The storage container extends transversely to the direction of travel and includes outlet openings arranged side by side, each of which is assigned a dosing device.

[0004] The dosing device is used to dispense granular material, i.e., seed and / or fertilizer, in controlled quantities and has a dosing housing that is open at the top and has two side walls arranged at a distance from one another. The dosing housing comprises an inlet, via which it is arranged at an outlet opening of the storage container, and an outlet, between which a dosing wheel is arranged on a shaft that can be driven to rotate in a dosing direction. The dosing wheel has end faces facing the side walls of the dosing housing, with a smooth wheel being arranged unattached on the shaft between the end faces and the side walls. Furthermore, a sealing element is arranged between the end faces of the dosing wheel and the side surfaces of the smooth wheels facing the end faces.

[0005] During operation, the distributor with its associated metering devices is moved across agricultural land, sometimes experiencing strong vibrations while the granular material freely trickles through the inlet onto the metering wheel. These vibrations, or even the fact that the distributor is moved onto slopes, can cause granular material to be accidentally conveyed over the metering wheel in the opposite direction to the metering direction. This can lead to local overdosing, as too much granular material is discharged from the metering devices, or the granular material is thrown out of the open housing of this metering device and distributed in an undesirable location on the agricultural land.

[0006] After operation of the distribution machine, small residual quantities of granular material usually remain in the dosing housings of the dosing devices, and the distribution machine is moved into the transport position. In the case of an at least partially foldable distribution machine, parts of the machine are folded up into an upright position or even folded down into a horizontal position rotated by approximately 180 degrees. A disadvantage of the dosing device described above is that, when at least partially rotated, it is not designed to prevent any residual quantities remaining in the dosing housing from undesired escape, as granular material can trickle unhindered through the dosing housing. A particularly disadvantageous situation would be that with this dosing device, the granular material would be tipped out of the open housing.This dosing device therefore has a lack of dosing accuracy, particularly on slopes and / or uneven terrain, and is unsuitable for use on at least partially folded machines.

[0007] Another dosing device is known from US 9,420,738 B2. This dosing device has several dosing wheels arranged on a shaft between two spaced-apart side walls, which can be non-positively connected to the shaft. The dosing wheels are each separated from one another by smooth wheels arranged loosely on the shaft. The disadvantages mentioned for the dosing device described above also apply to this dosing device, namely that the dosing accuracy is sometimes inadequate and it is not suitable for use on folded machines. Furthermore, this dosing device has no sealing elements between the dosing wheel and the smooth wheels, which creates the risk of grains becoming jammed there. Jammed grains further reduce dosing accuracy and can increase the required drive power if otherwise stationary smooth wheels are also driven by jammed grains.In the worst case, this can lead to the entire dosing system coming to a standstill.

[0008] Furthermore, US Pat. No. 6,158,630 A describes a metering device in which the smooth wheels are assigned to the metering wheel, so that they can be driven in rotation together by the shaft. This is disadvantageous because it requires increased drive power.

[0009] The object underlying the invention is to create a dosing device which has increased dosing accuracy and functional reliability.

[0010] This object is achieved by the features of patent claims 1 and 15. Advantageous developments of the invention are specified in the subclaims.

[0011] The dosing housing can be designed as a closed unit. The dosing wheel can be connected to the shaft in a force-locking manner, i.e. it can be brought into a driving connection, e.g. by means of a switchable coupling or a form-locking connection of the dosing wheel to the shaft. The filler part, which has smooth wheels, limits the movement of the dosing wheel on the shaft in the axial direction of the shaft towards the side wall of the dosing housing. The smooth wheels therefore serve as an axial guide for the dosing wheel. In addition, the filler part surrounds the dosing wheel in such a way that granular material can only be transported from the inlet to the outlet in the area of ​​the dosing wheel. In this way, the smooth wheels seal the dosing housing between the inlet and outlet in such a way that granular material is only conveyed in the area of ​​the dosing wheel. The smooth wheels are arranged unattached on the shaft, i.e. they are not positively driven by the shaft.During operation of the dosing device, the dosing wheel is driven in rotation while the smooth wheels are stationary. The filling part with the at least two smooth wheels can be designed as a single piece, with the dosing wheel preferably having a shortened hub and being able to be clicked between the smooth wheels with brief elastic deformation.

[0012] The invention further utilizes the knowledge that the effect of gravity may be insufficient to ensure that granular material is only transported along the dosing wheel in the dosing direction. The effect of gravity for the proper transport of the granular material in the dosing device is weakened during operation by vibrations and / or slopes or, in the case of at least partially foldable machines, acts in different directions in the operating and transport positions. By assigning the dosing wheel locking means which are designed to lock the dosing wheel against the transport of granular material against the dosing direction from the inlet to the outlet and / or in the dosing direction from the outlet to the inlet, the influence of gravity on the proper transport of the granular material is at least approximately eliminated. The locking means can rest elastically on the dosing wheel and slide over it in the dosing direction during operation.The advantage here is that granular material can only be discharged from the outlet via the rotating dosing wheel, i.e. it is at least almost prevented from automatically escaping from the dosing housing via the outlet in all positions. The blocking means can engage in a form-fitting manner between the sealing elements in the dosing wheel against the dosing direction, similar to the principle of a mechanical freewheel, so that granular material in the area of ​​the dosing wheel can only be transported in the dosing direction. This particularly advantageously prevents granular material from being transported past the dosing wheel against the dosing direction due to vibrations or similar. In particular, the dosing housing is divided by the blocking means into a conveying area, which extends in the dosing direction along the dosing wheel from the inlet to the outlet, and a non-conveying area, which extends in the dosing direction from the outlet to the inlet or outlet.extends from the inlet to the outlet against the dosing direction.

[0013] The sealing elements arranged between the front face of the metering wheel and the side surface of the smooth wheel also significantly reduce the risk of grains becoming jammed within the metering device, particularly between stationary and driven components, i.e., the smooth wheels and the metering wheel. The sealing elements can serve as a wearing part between the metering wheel and the smooth wheels. This means that in order to reduce wear on the metering wheel and / or the smooth wheels, the sealing elements are designed so that they wear out at least approximately instead of the metering wheel and / or the smooth wheels. In this respect, the sealing elements can act as a wearing part, like a sacrificial component between the metering wheel and the smooth wheels. The advantage here is that the sealing elements reduce the torque occurring between the metering wheel and the smooth wheels, thus reducing the required drive power.

[0014] In an advantageous further development of the dosing device, the sealing element is designed as an at least approximately semicircular sheet metal part, wherein the sheet metal part extends in the shape of a circular segment from the inlet in the direction of rotation of the dosing wheel to the outlet between the side surface of the respective smooth wheel and the end face of the dosing wheel. This further development is based on the idea that, particularly due to the locking means, the dosing wheel comes into contact with granular material almost exclusively in the direction of rotation of the dosing wheel, i.e. in the dosing direction, between the inlet and outlet. Without risking grains becoming jammed, the torque generated and thus the required drive power can be further reduced due to the minimized contact area between the sealing element and the dosing wheel by designing the sealing element as an approximately semicircular sheet metal part.

[0015] In an alternative advantageous development of the dosing device, the sealing element is designed as an annular sheet metal part, wherein the sheet metal part extends in a circle around the shaft between the side surface of the respective smooth wheel and the end face of the dosing wheel. The advantage of this development is that, due to the design of the sealing element as an annular sheet metal part, the dosing wheel is guided along its circumference by the sealing element. This results in improved concentricity of the dosing wheel and secure axial guidance of the dosing wheel on the shaft. This development is therefore characterized by increased operational reliability due to the improved concentricity of the dosing wheel and the additionally reduced risk of grains becoming jammed between the smooth wheels and the dosing wheel.

[0016] In a further particularly advantageous development of the dosing device, the annular sheet metal part has a recess in the area of ​​the outlet from the dosing housing, wherein the dosing device is configured by means of the recess to eject granular material clamped between the sheet metal part and the end face of the dosing wheel. Material clamped between the dosing wheel and the sheet metal part is rolled at least approximately along a circular path during operation of the dosing device. The recess creates an interruption in this circular path, so that the clamped material is released from the rolling contact in the area of ​​the outlet and falls into the outlet. The operational reliability of the dosing device is advantageously increased as a result of this measure.

[0017] The dosing device is further advantageously further developed in that the smooth wheels each have a recess in the area of ​​the outlet from the dosing housing. The dosing device is configured by means of at least one recess to eject granular material trapped between the smooth wheel and the end face of the dosing wheel. The recess increases the distance between the smooth wheel and the dosing wheel in the area of ​​the outlet, so that any trapped material falls out and is fed to the outlet. This is advantageous for the operational reliability of the dosing device.

[0018] In a further advantageous embodiment of the invention, at least one smooth wheel has a preferably elastic spring element acting in the direction of the side walls between the sealing element and the side surface facing the sealing element. Each smooth wheel preferably has a spring element. The spring element can have a spring travel of at least 1 mm. The spring element can serve to compensate for shape and position tolerances of the dosing device, in particular of the dosing housing, the dosing wheel, the smooth wheels and / or the sealing elements, by securely holding the sealing element in contact with the end face of the dosing wheel and the smooth wheel in contact with the side wall of the dosing housing. As a result of this measure, the tightness of the entire arrangement is increased and assembly and operational reliability are improved.

[0019] In another particularly advantageous embodiment of the invention, the spring element is designed as an annular foam part, wherein the foam part extends in a circle around the shaft between the side surface of the smooth wheel and the sealing element. The annular foam part simply holds the sealing element securely in contact with the metering wheel over the entire circumference of the wheel and presses the smooth wheel at least almost completely against the side wall of the metering housing. The axial alignment of the components arranged on the shaft is thus easily improved.

[0020] A particularly practical arrangement of the dosing device is achieved by arranging the dosing wheel at least approximately in the center between the spaced-apart side walls. The dosing device can be designed at least partially symmetrically, so that identical parts can be used to the right and left of the center, i.e., the dosing wheel. This simplifies the manufacturing costs of the dosing device.

[0021] In a further advantageous development of the dosing device, the sealing elements and / or the smooth wheels have means by which the sealing elements are positively attached to the respective smooth wheel. This simply prevents the sealing elements from being set into rotation by frictional contact with the dosing wheel and thus being driven. Furthermore, this creates defined contact conditions between the dosing wheel and the sealing element, which can advantageously be considered when designing the components, in particular the sealing elements as wear partners.

[0022] To reduce the contact area between the metering wheel and the sealing elements, a further advantageous development of the metering device provides for the end faces of the metering wheel to be trough-shaped. This development is therefore characterized by a particularly reduced torque requirement and a reduced required drive power.

[0023] The dosing device is also advantageously further developed in that the dosing wheel is at least approximately as wide as a smooth wheel. This results in a favorable ratio of 2:1 between the conveying area and the smooth area for the unit consisting of the dosing wheel and the smooth wheels arranged on both sides.

[0024] In a further advantageous embodiment of the dosing device, the filling part comprising the at least two smooth wheels is formed as a single piece. Formed as a single piece, i.e., consisting of a single part. The filling part can, for example, be a plastic part produced by injection molding. This advantageously reduces the number of individual parts and eliminates an assembly step. The filling part can be designed to be at least partially elastic, so that the dosing wheel can be inserted into the filling part between the smooth wheels and removed from the filling part. It is also advantageous that, as a result of this measure, the dosing wheel is guided particularly securely between the smooth wheels.

[0025] In a further advantageous development of the dosing device, the dosing wheel, the sealing elements, and the at least one spring element have a virtually identical outer diameter. The outer diameter of the dosing wheel is measured based on the outer diameter of any conveying elements arranged on the outer surface of the dosing wheel, such as blades. As a result of this development, the dosing device is designed to be particularly dense in a simple manner, so that granular material is conveyed almost exclusively in the area of ​​the dosing wheel by its rotation. The granular material can thus be dosed particularly precisely by controlling the dosing wheel drive.

[0026] In a further advantageous embodiment, the blocking means comprise at least one elastic sealing lip. The elastic sealing lip can be arranged in contact with the metering wheel so that it sweeps over the metering wheel. The transport of granular material against the metering direction is thus almost completely blocked. This prevents unwanted leakage of material and increases metering accuracy.

[0027] In another advantageous embodiment, the blocking means comprise at least one brush element. The brush element can have bristles that sweep over the dosing wheel. This is advantageous because the dosing wheel is additionally cleaned by the blocking means designed as a brush element. Dust and other particles are swept off the dosing wheel by the brush element during operation, thereby increasing dosing accuracy.

[0028] The object of the invention is also achieved by a distribution machine of the type mentioned above, wherein the dosing device is designed according to at least one of the above embodiments. Regarding the advantages of the distribution machine, reference is made to the advantages of the various embodiments of the dosing device.

[0029] Further details of the invention can be found in the example description and the drawings. The drawings show Fig.1 a perspective view of a single-seed seed drill mounted behind a tractor, Fig.2 a dosing device with a closed dosing housing in perspective view, Fig.3 the dosing device, according to Fig.2 , wherein the dosing housing is opened and reveals a first embodiment of a dosing wheel, in perspective view, Fig.4 the dosing wheel removed from the dosing housing, according to Fig.2-3 , in perspective view, Fig.5 the dosing wheel, according to Fig.2-4 , in exploded view, Fig.6 the dosing wheel, according to Fig.2-5 , in cross-sectional view, Fig.7 the dosing wheel, according to Fig.2-6 , in longitudinal section, Fig.8 a second embodiment of a dosing wheel removed from a dosing housing in perspective view, Fig.9 the dosing wheel, according to Fig.8 , in exploded view, and Fig.10 the dosing wheel, according to Fig.8-9 , in longitudinal section view.

[0030] A distribution machine arranged behind a tractor 1 and designed as a single-seed seeder 2 is in Fig.1 can be seen. The precision seed drill 2 has a storage hopper 3 for seed and / or fertilizer at its front end in the direction of travel F and a plurality of sowing units 4 arranged next to one another transversely to the direction of travel F at its rear end. The storage hopper 3, which is mounted on the frame of the precision seed drill 2, is funnel-shaped and has outlet openings at its lower end covered by the sowing units 4, each of which is assigned a metering device 5 for granular material. In this precision seed drill 2, the number of outlet openings or metering devices 5 corresponds to the number of sowing units 4, with each metering device 5 being set up to dispense material stored in the storage hopper 3 in metered quantities and being connected to a sowing unit 4 via discharge lines (not shown). In this way, additional fertilizer and / or seed from the storage hopper 3 can be distributed to the sowing units 4.

[0031] It is also conceivable for the storage container 3 to have a number of outlet openings with metering devices 5 that differs from the number of sowing units 4. In the event that there are more metering devices 5 than sowing units 4 on the precision seed drill 2, it is conceivable for a sowing unit 4 to be supplied by more than one metering device 5 and / or for at least one metering device 5 to be switched off or the associated outlet opening to be closed by a gate valve 6. In the event that there are more sowing units 4 than metering devices 5 on the precision seed drill 2, it is conceivable for one metering device 5 to supply multiple sowing units 4 with material. For this purpose, only a split discharge line can be used, for example.

[0032] The sowing units 4 are arranged side by side on a frame of the precision seed drill 2, transverse to the direction of travel F, and each carry two material tanks 7a, 7b, a first material tank 7a preferably for seed and a second material tank 7b preferably for seed and / or fertilizer. The first material tank 7a is connected to a concealed singulating device for the singular dispensing of seed in order to distribute the seed over an agricultural area during operation. The second material tank 7b, which can also be referred to as a microgranulate tank, is also assigned a metering device 5 for distributing the stored material.

[0033] Such a dosing device 5, as used on the storage container 3 and the second material tank 7b, is shown in Fig.2 in an isolated view from the precision seed drill 2. The metering device 5 is arranged via the gate valve 6 at an outlet opening of the storage container 3 or the material tank 7b. The gate valve 6 can be moved at least between a closed and an open position, so that granular material can enter the metering device 5 via an inlet 8. The metering device 5 has a closed metering housing 9. The metering housing 9 is further essentially formed by two spaced-apart, opposite side walls 10, between which an outlet 11 extends at the lower end, and a housing flap 12. A discharge line can be connected to the outlet 11, so that the material discharged by the metering device 5 is distributed at the desired location.

[0034] The housing flap 12 can be folded down about a pivot axis so that the dosing housing 9 is opened and provides a view of a first embodiment of a dosing wheel 13, as Fig.3 shows. In In this position, the metering wheel 13, which is arranged between the inlet 8 and the outlet 11 and at least approximately in the middle between the spaced-apart side walls 10, can be removed from the metering housing 9. The Fig.2-7 show a first embodiment of the dosing wheel 13, wherein the dosing wheel 13 in a view taken from the dosing housing 9 in the Fig.4-7 A second embodiment of the metering wheel 13 is shown in the Fig.8-10 in the position removed from the dosing housing 9.

[0035] The metering wheel 13 has end faces 13a facing the side walls 10 and, when installed in the metering housing 9, is arranged on a shaft (not shown), to which it can be non-positively connected. For this drive connection to the shaft, the metering wheel 13 has a hub 13b and can thus be driven in rotation in a metering direction D. Furthermore, the metering wheel 13 is assigned locking means 14, which are designed to lock the metering wheel 13 against the transport of granular material, counter to the metering direction D from the inlet 8 to the outlet 11 and in the metering direction D from the outlet 11 to the inlet 8. To the right and left of the dosing wheel 13, more precisely on each end face 13a of the dosing wheel 13, a smooth wheel 15 is arranged, which extends between the respective end face 13a and the respective side wall 10 of the dosing housing 9.The smooth wheels 15 together form a so-called filling part and thus at least approximately fill the installation space between the dosing wheel 13 and the side walls 10 within the dosing housing 9, so that granular material is guided at least approximately exclusively in the area of ​​the dosing wheel 13 from the inlet 8 to the outlet 11 through the dosing housing 9. The smooth wheels 15 are arranged unattached on the shaft (not shown), so that they are not driven during rotating operation of the dosing wheel 13. In the present embodiments, the filling part is designed in two parts. The smooth wheels 15 can be releasably attached and plugged together to form the filling part. In an embodiment not shown, the filling part is designed in one piece, i.e., in one piece.

[0036] A sealing element 16 is also arranged on both sides of the metering wheel 13 between the respective end face 13a and a side surface 15a of the respective smooth wheel 15 facing this end face 13a. In this first embodiment of the metering wheel 13, the sealing element 16 is designed as an annular sheet metal part and extends in a circle around the shaft between the side surface 15a of the smooth wheel 15 and the end face 13a of the metering wheel 13.

[0037] The sealing element 16 is intended to prevent granular material from becoming jammed between the driven metering wheel 13 and the stationary smooth wheels 15. It is arranged in a form-fitting, rotationally fixed manner on the smooth wheel 15 via fastening grooves 16b on the sealing element 16 and corresponding means designed as anti-twist devices 15b on the smooth wheel 15 that engage in the fastening grooves 16b. During operation of the metering device 5, the sealing element 16 is therefore stationary. Should individual grains nevertheless become jammed between the metering wheel 13 and a smooth wheel 15, the sealing element 16, designed here as an annular sheet metal part, has a recess 16a in the area of ​​the outlet 11 from the metering housing 9.The otherwise flat, circular contact between the sealing element 16 and the end face 13a of the dosing wheel 13 is interrupted by the recess 16a, so that space is released locally for clamped material and the dosing device 5 is configured by means of the recess 16a to eject granular material clamped between the sealing element 16 and the end face 13a.

[0038] The blocking means 14, provided to prevent the unwanted escape of granular material from the dosing device 5, are arranged in the area of ​​the inlet 8 on the upper side of the dosing wheel 13 and in the area of ​​the outlet 11 on the lower side of the dosing wheel 13 and comprise an elastic sealing lip 14a. In an embodiment not shown, the blocking means 12 may alternatively or additionally comprise at least one brush element. As the cross-sectional view of the dosing wheel 13 in Fig.6 shows, the sealing lips 14a flexibly engage the metering wheel 13. In the area of ​​the inlet 8, this prevents granular material from being transported from the inlet 8 to the outlet 11 against the metering direction D, both when the metering wheel 13 is stationary and when it is driven in the metering direction D. In the area of ​​the outlet 11, the sealing lip 14a also flexibly engages the metering wheel 13 and thus prevents granular material from being transported in the metering direction D from the outlet 11 to the inlet 8 when the metering wheel 13 is stationary. When the dosing wheel 13 is driven, the granular material is carried in and / or between conveying elements 13c arranged on the outer surface of the dosing wheel 13 into the wedge between the sealing lip 14a and the dosing wheel 13 and, after passing between the dosing wheel 13 and the sealing lip 14a, trickles into the outlet 11.For fastening the locking means 14, two screws 14b are provided, by means of which they can be fixed in holes provided on the smooth wheels 15, as shown. Fig.4 and 5 show.

[0039] To enable easy assembly of the dosing device 5, in particular of the dosing wheel 13, a spring element 17 designed as an annular foam part, in particular a foam spring, is arranged between the sealing element 16 and the side surface 15a of the two smooth wheels 15 facing the sealing element 16. The spring element 17, designed here as an annular foam part, surrounds the shaft (not shown) in a circle and extends between the side surface 15a of the respective smooth wheel 15 and the respective sealing element 16. The spring element 17 acts in the direction of the side walls 10 and has a spring travel of at least approximately one millimeter, so that the sealing element 16 is held securely in contact with the end face 13a of the dosing wheel 13 by means of the spring element 17. Fig.7 The first embodiment of the metering wheel 13 can be seen in a longitudinal sectional view. Because the smooth wheels 15 rest against the side walls 10 and the spring element 17 is supported on the side surface 15a of the smooth wheels 15 and acts in this direction, the sealing element 16 is held elastically and resiliently in contact with the respective end face 13a of the metering wheel 13 in the manner described above. The sealing of the metering wheel 13 is thus improved and fewer grains are clamped between the metering wheel 13 and the sealing element 16. Furthermore, the spring element 17 compensates for the manufacturing tolerances of the components arranged on the shaft (not shown), namely the metering wheel 13, smooth wheels 15 and sealing elements 16, by the spring element 17 either being compressed or expanding. The assembly of the metering device 5 and in particular of the metering wheel 13 is thus particularly facilitated.

[0040] How Fig.7 also shows, the end faces 13a of the dosing wheel 13 are trough-shaped. Transverse to the dosing direction D, i.e. the rotational movement of the dosing wheel 13 during operation, this results in a particularly small friction surface between the end face 13a and the adjacent sealing elements 16. On the one hand, this reduces the torque required to drive the dosing wheel 13 and, on the other hand, defined contact conditions arise between the dosing wheel 13 and the sealing element 16, which allow the sealing element 16 to act as a sacrificial component for the dosing wheel 13. The material combination of the dosing wheel 13 and the sealing element 16 is selected such that the sealing element 16 wears first, i.e. serves as a wear partner. This has the advantage that, during regular maintenance work, the dosing wheel 13 needs to be replaced less frequently than the sealing element 16, whereby the sealing element 16 is very cost-effective to procure. As a result, maintenance costs are easily saved.

[0041] In the Fig.8-10 A second embodiment of the metering wheel 13 is shown in the position removed from the metering housing 9. Parts with the same function are identified by the same reference numerals as in the first embodiment. Fig.8 As shown, this metering wheel 13 is also assigned a smooth wheel 15 and a sealing element 16 on each side. The sealing elements 16 are positively secured to the smooth wheels 15, and both parts are stationary during the rotationally driven operation of the metering wheel 13 via the hub 13c.

[0042] In Fig.9 The second embodiment of the metering wheel 13 is shown in an exploded view. In this embodiment, the sealing elements 16 are designed as at least approximately semicircular sheet metal parts and extend from the inlet 8 in the direction of rotation of the metering wheel 13, i.e., metering direction D, in the shape of a circular segment to the outlet 11 between the side surface 15a of the respective smooth wheel 15 and the end face 13a of the metering wheel 13. This embodiment has the advantage that even less friction occurs between the metering wheel 13 and the sealing elements 16, since these essentially only extend over the part of the circumference of the metering wheel 13 in which granular material is transported.

[0043] To prevent grains from becoming jammed between the dosing wheel 13 and the smooth wheel 15, the smooth wheels 15 are each provided with a recess 15c in the area of ​​the outlet 11 from the dosing housing 9. The recesses 15c create an increased distance between the dosing wheel 13 and the respective smooth wheel 15, so that the dosing device 5 is configured, by means of the recesses 15c, to eject granular material jammed between the respective smooth wheel 15 and the end face 13a of the dosing wheel 13.

[0044] How Fig.10 , as well as Fig.7 Furthermore, the metering wheel 13 is at least approximately as wide as one of the smooth wheels 15. Furthermore, the metering wheel 13 and the sealing elements 16, as well as the smooth wheels 15, have a virtually identical outer diameter. The spring elements 17 of the first embodiment also have an at least approximately identical outer diameter, as do the smooth wheels 15, the sealing elements 16 and the metering wheel 13, as Fig.7 shows. Bezugszeichenliste

[0045] 1Agricultural tractor 2Precision seed drill FDirection of travel 3Supply container 4Sowing unit 5Dosing device 6Shut-off slide 7a,bMaterial tank 8Inlet 9Dosing housing 10Side walls 11Outlet 12Housing flap 13Dosing wheel 13aFront side 13bHub 13cConveyor element DDosing direction 14Locking means 14aSealing lip 14bScrew 15Smooth wheel 15aSide surface 15bAnti-rotation device 15cRecess 16Sealing element 16aRecess 16bFastening groove 17Spring element

Claims

1. Metering device (5) for granular material, in particular seed and / or fertilizer, the metering device (5) comprising a metering housing (9) having at least one inlet (8) and at least one outlet (11) for the granular material and two side walls (10) arranged at a distance from one another, a metering wheel (13) with end faces (13a) that face the side walls (10) being arranged on a shaft, between the inlet (8) on one side and the outlet (11) on the other side and between the side walls (10) arranged at a distance from one another, so as to be form-fittingly connectable to the shaft and drivable by the shaft such that it is rotatable in a metering direction (D), the metering device (5) comprising a filling part, which has at least two smooth wheels (15) arranged on the shaft in an unattached manner, a smooth wheel (15) that extends between the relevant end face (13a) and the side wall (10) being arranged on each end face (13a) of the metering wheel (13), a sealing element (16) being arranged on both sides between the particular end face (13a) of the metering wheel (13) and a side surface (15a) of the particular smooth wheel (15) that faces this end face (13a), characterized in that the metering wheel (13) is assigned blocking means (14) which are designed to block the metering wheel (13), counter to the metering direction (D) from the inlet (8) to the outlet (11) and / or in the metering direction (D) from the outlet (11) to the inlet (8), against the transportation of granular material, and the metering wheel (13), the sealing elements (16) and the smooth wheels (15) have an almost identical outer diameter.

2. Metering device (5) according to claim 1, characterized in that the sealing element (16) is designed as an at least approximately semicircular sheet metal part (16), in that the sheet metal part (16) extends from the inlet (8) in the direction of rotation (D) of the metering wheel (13) in the shape of a segment of a circle to the outlet (11) between the side surface (15a) of the particular smooth wheel (15) and the end face (13a) of the metering wheel (13).

3. Metering device (5) according to claim 1, characterized in that the sealing element (16) is designed as an annular sheet metal part (16), in that the sheet metal part (16) extends in a circle around the shaft between the side surface (15a) of the particular smooth wheel (15) and the end face (13a) of the metering wheel (13).

4. Metering device (5) according to claim 3, characterized in that the annular sheet metal part (16) has a recess (16a) in the region of the outlet (11) from the metering housing (9), in that the metering device (5) is designed by means of the recess (16a) to eject granular material jammed between the sheet metal part (16) and the end face (13a) of the metering wheel (13).

5. Metering device (5) according to claim 2 or 4, characterized in that the smooth wheels (15) each have a recess (15c) in the region of the outlet (11) from the metering housing (9), in that the metering device (5) is designed by means of at least one recess (15c) to eject granular material jammed between the smooth wheel (15) and the end face (13a) of the metering wheel (13).

6. Metering device (5) according to at least one of the preceding claims, characterized in that at least one smooth wheel (15) has a preferably resilient spring element (17) acting in the direction of the side walls (10) between the sealing element (16) and the side surface (15a) that faces the sealing element (16).

7. Metering device (5) according to claim 6, characterized in that the spring element (17) is designed as an annular foam part (17), in that the foam part (17) extends in a circle around the shaft between the side surface (15a) of the smooth wheel (15) and the sealing element (16).

8. Metering device (5) according to at least one of the preceding claims, characterized in that the metering wheel (13) is arranged at least approximately in the middle between the side walls (10) arranged at a distance from one another.

9. Metering device (5) according to at least one of the preceding claims, characterized in that the sealing elements (16) and / or the smooth wheels (15) have means (15b, 16b) by means of which the sealing elements (16) are form-fittingly attached to the particular smooth wheel (15).

10. Metering device (5) according to at least one of the preceding claims, characterized in that the end faces (13a) of the metering wheel (13) are trough-shaped.

11. Metering device (5) according to at least one of the preceding claims, characterized in that the filling part having the at least two smooth wheels (15) is formed in one piece.

12. Metering device (5) according to claim 6, characterized in that the metering wheel (13), the sealing elements (16) and the at least one spring element (17) have an almost identical outer diameter.

13. Metering device (5) according to at least one of the preceding claims, characterized in that the blocking means (14) comprise at least one resilient sealing lip (14a).

14. Metering device (5) according to at least one of the preceding claims, characterized in that the blocking means (14) comprise at least one brush element.

15. Distribution machine (2) for spreading seed and / or fertilizer comprising a storage container (3) for seed and / or fertilizer and at least one metering device (5) assigned to an outlet opening of the storage container (3), characterized in that the metering device (5) is designed according to at least one of claims 1 to 14.