Metering unit for seeding machine and associated isolation method

Abstract

A metering unit for a seeding machine and a related isolation method. The invention relates to a metering unit for a seeding machine, comprising: a closed housing (1) comprising a fixed part (2) and a movable door (3), the fixed part (2) of the housing (1) comprising an inlet for particulate material associated with a baffle plate operable by a selection element (12) to place the baffle plate in a sealed or open position, in a closed position (POFF), in which the baffle plate (2) is closed by the selection element (12), or in a closed position (POFF), in which the baffle plate (2) is closed by the selection element (12); the door (3) is locked in a locked state (E1) or unlocked in an unlocked state by means of a locking device (13), characterized in that, in a closed position (POFF) of the door (3), the locking device (13) and the selection element (12) are configured such that the door (3) is held in the locked state (E1) by the locking device (13) as long as the flap is in the open position, and the selection element (12) is held in the unlocked state (E2) as long as the flap is in the closed position (POFF). Operation of a selection element (12) to displace the shutter from the open position to the sealed position causes the locking means (13) to operate to allow the door (3) to switch to the unlocked state.

Description

Technical Field

[0001] The invention relates to the field of metering units for seed drills.

[0002] The invention therefore relates more generally to the field of single seed sowing, also known as precision sowing, i.e. sowing seed by seed in a single row, which is used for corn, sugar beets, soybeans or similar crops. Background Art

[0003] Single-seed planters typically utilize a beam chassis with parallelogram-shaped planting elements attached to it. These elements typically range from 4 to 12, or even more. The spacing between these elements varies depending on the crop, preferably between 37.5 and 80 centimeters, but allows for the formation of very distinct rows. Therefore, in this context, the term "seed planter" generally refers to row crops, rather than crops with much tighter spacing, such as wheat.

[0004] In a known manner, a metering unit for a single seed drill generally operates as follows.

[0005] The two-part, sealed housing features a perforated metering disc that is driven to rotate, preferably by a motor, forming a metering element for a plurality of particulate materials. The metering disc divides the housing into two chambers with different air pressures, thereby generating a pressure differential across the perforated metering disc that can be positive or negative. The housing is connected to a blower that manages the pressure differential depending on seed type, feed rate, and other parameters.

[0006] Below the perforated metering disc, in other words, at the bottom of the housing, there is a reservoir for granular material such as seeds, which are usually supplied from a hopper. These seeds come into contact with the rotating perforated metering disc, which pulls the seeds one by one into its perforations as it rotates.

[0007] The diameter and shape of the opening in the metering disc are designed to accommodate a single particle of material, such as a seed, which is retained in the opening by a pressure differential across the disc. Special features, such as ridges and / or depressions, are often incorporated into the disc along the edges of the opening to guide and / or direct the seed into the opening. These areas around the opening are often referred to as agitation elements.

[0008] Once the seeds have been distributed into the openings of the metering disc, a system known as a selection system can eliminate excess seeds to avoid duplication, as several seeds may be accommodated in a single opening, which is undesirable. Selection can be performed using teeth, brushes, or the like that are fixedly mounted and located outside and / or inside the seed path. As a result, excess seeds fall back into the storage area.

[0009] Once the seeds are selected, they are transported to the final distribution area, typically located in the last quarter turn of the metering disc, where there is no longer a pressure differential. This lack of pressure differential causes the seeds to leave the openings and exit the metering unit toward the ground. Seed discharge can be assisted by rollers that break the pressure differential and may also have spikes that push the seeds out of the openings.

[0010] In certain cases, the movable door of the sealing housing must be opened, for example, in order to replace the metering disc and / or to perform cleaning and / or maintenance operations and / or to discharge the seeds and / or make adjustments.

[0011] In these cases, it is desirable to be able to isolate the housing from the hopper containing the seeds to prevent the seeds from entering the housing.

[0012] For this purpose, the inlet for the seeds to enter the housing is in the form of a pipe, which is selectively opened or not opened by a baffle. The baffle can also be partially opened to influence the seed inlet flow rate entering the housing.

[0013] When it is desired to isolate the housing from the hopper, this inlet must be completely sealed by closing the damper. The damper is moved between different positions by a lever manually operated by the operator. The lever is mounted on the outside of the metering housing. A display on the housing indicates the position of the lever.

[0014] Until now, operators had to ensure the seed inlet was properly closed before opening the housing door. Otherwise, when the operator removed the metering disc, seed would continue to flow into the housing and fall to the ground. However, it was not uncommon for operators to forget to close the seed inlet, which meant that seed would sometimes accidentally fall to the ground. Summary of the Invention

[0015] The present invention aims to overcome at least one of these drawbacks and to provide a solution capable of automatically isolating the housing from the hopper under certain conditions.

[0016] To this end, the present invention relates to a metering unit for a seed drill, comprising at least:

[0017] - a closed housing comprising at least a fixed portion and a door movable between an open position and a closed position,

[0018] - a metering element for a plurality of granular materials, arranged for discrete single-grain dispensing of the plurality of granular materials,

[0019] A metering element is disposed within the housing to separate the interior of the housing into a first chamber and a second chamber, the first chamber being configured to receive all or a portion of the plurality of particulate materials at least in the storage area, and the second chamber being enclosed by a door at least in a closed position.

[0020] The fixed part of the housing also comprises an inlet for granular material, the inlet for granular material opening into the first chamber, associated with the baffle, the inlet for granular material being configured to be connected to a conveying device connected to the hopper,

[0021] The shutter is operable by a selection element to at least selectively place the shutter in a sealing position for the inlet for the granular material, wherein the shutter seals the inlet for the granular material, or in an open position for the inlet for the granular material, wherein the shutter does not completely seal or partially seals the inlet for the granular material.

[0022] In the closed position, the door is locked at least in a locked state or unlocked in an unlocked state by at least the locking device,

[0023] The characteristics of the metering unit are:

[0024] In the closed position of the door, the locking device and the selection element are configured so that:

[0025] - the door is held in a locked state by the locking device as long as the flap is in the open position or not in the sealing position, and

[0026] Operation of the selection element for moving the flap from the open position to the sealing position causes the locking device to operate to allow the door to be switched to the unlocked state or to cause the door to be switched to the unlocked state.

[0027] The invention further relates to a sowing element comprising at least one hopper arranged to receive a plurality of granular materials and connected to a metering unit via a conveying device, characterised in that the metering unit is a metering unit according to the invention.

[0028] The invention also relates to a sowing machine comprising at least one chassis on which at least one sowing element is mounted, characterised in that the at least one sowing element is a sowing element according to the invention.

[0029] The invention also relates to a method for locking / unlocking a metering unit for a seed drill, which contains a plurality of granular materials at least in a storage area, characterized in that the metering unit is a metering unit according to the invention and the method comprises:

[0030] a locking phase during which, in the closed position of the door, the flap is in the open position and the door is held in the locked state by the locking device, and

[0031] - an isolation phase during which, in the closed position of the door, the selection element is operated to move the flap from the open position to the sealing position, causing the locking device to operate to allow the door to be switched to the unlocked state or to cause the door to be switched to the unlocked state. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The invention will be better understood through the following description, which refers to several preferred embodiments given as non-limiting examples and illustrated with reference to the accompanying schematic drawings, in which:

[0033] Figure 1 A perspective view showing a metering unit according to the present invention comprising a door held in a locked state by a locking device and a selection element configured to bring the shutter into an open position,

[0034] Figure 2 show Figure 1 Front view of the measuring unit,

[0035] Figure 3 show Figure 1 A partial perspective view of the door and locking device of the metering unit,

[0036] Figure 4 show Figure 1 Rear view of the metering unit,

[0037] Figure 5 show Figure 1 A partial perspective view of selected elements of the metering unit,

[0038] Figure 6 show Figure 1 Front view of the middle metering unit without door,

[0039] Figure 7 A front view of a metering unit according to the present invention is shown, comprising a door held in a locked state by a locking device and a selection element configured to bring the shutter into a sealing position,

[0040] Figure 8 show Figure 7 A partial perspective view of selected elements of the metering unit,

[0041] Figure 9 A front view of a metering unit according to the present invention is shown, comprising a door in an unlocked state and a selection element configured to bring the shutter into a sealing position,

[0042] Figure 10 A front view of a metering unit according to the present invention is shown with the door removed, the metering unit comprising a selection element configured to bring the shutter into a sealing position,

[0043] Figure 11 show Figure 1 A perspective view of a portion of the selected element and the baffle of the metering unit, and

[0044] Figure 12 show Figure 1 Perspective view of the door and metering element of the metering unit. DETAILED DESCRIPTION

[0045] As shown in the figure, the metering unit for the seed drill includes at least:

[0046] a closed housing 1 comprising at least a fixed portion 2 and a door 3 movable between an open position PON and a closed position POFF,

[0047] a metering element 4 for a plurality of granular materials, arranged for discrete, single-grain dispensing of the plurality of granular materials,

[0048] A metering element 4 is arranged in the housing 1 to divide the interior of the housing 1 into different first and second chambers 5 and 6, the first chamber 5 being configured to receive all or part of the plurality of granular materials in at least a storage area 7, the second chamber 6 being closed by the door 3 which is at least in its closed position POFF.

[0049] The fixed part 2 of the housing 1 also comprises an inlet 8 for granular material, which opens into the first chamber 5 and is associated with a baffle 9, the inlet 8 for granular material being configured to be connected to conveying means 10, 11 connected to a hopper (not shown).

[0050] The baffle 9 can be operated by a selection element 12 to at least selectively place the baffle 9 in a sealing position PO for the inlet 8 for the granular material, in which the baffle 9 seals the inlet 8 for the granular material, or in at least one open position PA for the inlet 8 for the granular material, in which the baffle 9 does not completely seal or partially seals the inlet 8 for the granular material.

[0051] In the closed position POFF, the door 3 is locked at least in the locked state E1 or unlocked in the unlocked state E2 by at least the locking device 13 .

[0052] According to the invention, the metering unit is characterized in that:

[0053] In the closed position POFF of the door 3, the locking device 13 and the selection element 12 are configured such that:

[0054] - the door 3 is held in the locked state E1 by the locking device 13 as long as the flap 9 is in the open position PA or not in the sealed position PO, and

[0055] The operation of the selection element 12 for moving the flap 9 from the open position PA to the sealed position PO causes the locking device 13 to operate in order to allow or cause the door 3 to switch to the unlocked state E2 .

[0056] Advantageously, due to this configuration, the operator is only allowed to open door 3 by moving it from closed position POFF to open position PON after selector 12 has operated flap 9 so that it is in sealing position PO, in which flap 9 seals inlet 8 for the granular material. Thus, under these conditions, the contents of the hopper are isolated from first chamber 5 of housing 1, meaning that, with door 3 of housing 1 open, no granular material can continue to flow from the hopper via conveying devices 10, 11 to first chamber 5 of housing 1. In other words, if door 3 is to be opened, inlet 8 must be completely closed using flap 9.

[0057] In fact, if the damper 9 is in the open position PA, which allows particulate material to enter the first chamber 5 of the housing 1 through the inlet 8, the door 3 is held closed in the closed position POFF because it is locked by the locking device 13, thereby preventing the door 3 from opening, and thus the door is in the locked state E1. Furthermore, if the damper 9 is in the sealed position PO, which prevents particulate material from entering the first chamber 5 of the housing 1 through the inlet 8, the door 3 can be opened in the open position PON because the selector 12 operates the locking device 13, thereby allowing the locking device 13 to be unlocked or causing the locking device 13 to be unlocked. In the latter case, the switching of the door 3 from the locked state E1 to the unlocked state E2 is possible or automatic.

[0058] Preferably, the locking device 13 includes a first locking element 14 and a second locking element 15. In the closed position POFF, the door 3 is locked in at least the locked state E1 or unlocked in the unlocked state E2 by at least the first locking element 14. The second locking element 15 is movable between a locked position PV and an unlocked position PDV. In the closed position POFF of the door 3, the second locking element 15 and the selection element 12 are configured to cooperate with each other so as to:

[0059] - as long as the flap 9 is in the open position PA or not in the sealing position PO, the second locking element 15 remains in the locked position PV, preventing the first locking element 14 from being unlocked, thereby keeping the door 3 in the locked state E1, and

[0060] Operation of the selection element 12 for moving the flap 9 to the sealing position PO causes the second locking element 15 to move from the locked position PV to the unlocked position PDV, allowing the first locking element 14 to be unlocked and the door 3 to be switched from the locked state E1 to the unlocked state E2.

[0061] In this configuration, the door 3 can be locked in the locked state E1 or unlocked in the unlocked state E2 by means of the first locking element 14, allowing for switching between the two states. The door 3 can be locked in the locked state E1 by means of the second locking element 15, which interacts with the selector 12, as long as the second locking element 15 is in the locked position PV. If the second locking element 15 is in the unlocked position PDV, the door 3 can be switched from the locked state E1 to the unlocked state E2. If the selector 12 places the flap 9 in the open position PA, the second locking element 15 is in the locked position PV. On the other hand, if the selector 12 places the flap 9 in the sealed position PO, the second locking element 15 is in the unlocked position PDV.

[0062] Preferably, in at least one open position PA of the shutter 9 corresponding to at least one first position P1 of the selection element 12 , the selection unit 12 is configured not to operate the second locking element 15 so that the second locking element remains in the locking position PV.

[0063] Advantageously, in this configuration, in said at least one first position P1 , the selection element 12 and the second locking element 15 do not mechanically cooperate with each other.The second locking element 15 is in the locking position PV.

[0064] Preferably, in the sealing position PO of the shutter 9 corresponding to the second position of the selection element 12 , the selection element 12 is configured to operate the second locking element 15 so that the second locking element is in the unlocking position PDV.

[0065] Advantageously, in this configuration, in the second position, the selection element 12 and the second locking element 15 mechanically cooperate with each other.The second locking element 15 is in the unlocking position PDV.

[0066] Preferably, the selection element 12 comprises a lever 16 mounted so as to be movable on the fixed part 2 of the housing 1 , at least selectively positionable in said at least one first position P1 and in said second position, mechanically connected to the baffle 9 and preferably comprising gripping means 26 for manual operation of the lever 16 .

[0067] Advantageously, the selection element 12 of this non-limiting example is easy for an operator to manipulate.

[0068] Preferably, in the closed position POFF, the door 3 covers the opening 17 of the fixed part 2, and the door 3 is installed so that it can be tightened / unscrewed relative to the opening 17 by the first locking element 14 in the closed position POFF between a locked state E1 in which the door 3 is tightened and an unlocked state E2 in which the door 3 is unscrewed.

[0069] Advantageously, in this non-limiting example, the door 3 is in a locked state E1 if it is screwed onto the fixed part 2, whereas it is in an unlocked state E2 if it is unscrewed from the fixed part 2. In this unlocked state E2, the door 3 is no longer attached to the fixed part 2 and can therefore be removed from the fixed part 2 so as to no longer cover the opening 17 and to be placed in the open position PON.

[0070] Preferably, the second locking element 15 includes a latch 18 and a protrusion 20 protruding from the outer periphery of the door 3, the latch being pivotally mounted on the fixed part 2 of the housing 1 between a locking position PV and an unlocking position PDV, the latch being reset by a reset device 19 mounted on the fixed part 2 of the housing 1, the latch 18 being held against the protrusion 20 by the reset device 19 in the locking position PV to prevent the door 3 from rotating to keep the door 3 in the locked state E1, the latch 18 being separated from the protrusion 20 in the unlocking position PDV to allow the door 3 to rotate to allow the door 3 to switch to the unlocked state E2.

[0071] Advantageously, in this non-limiting example, if the latch 18 abuts against the protrusion 20, which corresponds to the locked position PV, the door 3 cannot be driven to rotate and thus cannot be unscrewed, and the door is locked in the locked state E1. On the other hand, if the latch 18 is separated from the protrusion 20, which corresponds to the unlocked position PDV, the door 3 can be driven to rotate and thus unscrewed, and the door can be moved to the unlocked position E2.

[0072] Preferably, the latch 18 comprises an operable portion 21 operable by the operating lever 16 , and when moved to the second position, the operating lever 16 is configured to operate the operable portion 21 and exert a force against the reset force of the reset device 19 to pivot the latch 18 to the unlocked position PDV.

[0073] In this non-limiting example, due to the mechanical cooperation between the selection element 12 and the second locking element 15 in the form of the pivoting latch 18, the second locking element 15 can be caused to move from the locking position PV to the unlocking position PDV by the operable part 21 during the movement of the selection element 12 from the first position P1 to the second position.

[0074] The invention also relates to a sowing element comprising at least one hopper arranged to contain a plurality of granular materials and connected via conveying means 10, 11 to a metering unit, characterised in that the metering unit is in accordance with the invention and as described above.

[0075] The invention also relates to a sowing machine comprising at least one chassis on which at least one sowing element is mounted, characterised in that the at least one sowing element is in accordance with the invention and as described above.

[0076] The present invention also relates to a method for locking / unlocking a metering unit of a seed drill, the seed drill comprising a plurality of granular materials at least in a storage area 7, characterized in that the metering unit is a metering unit according to any one of the claims of the present invention, and the locking / unlocking method comprises:

[0077] - a locking phase, during which the door 3 is in the closed position POFF, the flap 9 is in the open position PA, and the door 3 is held in the locked state E1 by the locking device 13, and

[0078] - Isolation phase, during which, in the closed position POFF of the door 3, the selection element 12 is operated to move the baffle 9 from the open position PA to the sealed position PO, causing the locking device 13 to operate to allow the door 3 to switch to the unlocked state E2 or cause the door 3 to switch to the unlocked state E2.

[0079] Advantageously, due to the method according to the invention, during the locking phase, the inlet 8 is partially or completely opened by the flap 9 (open position PA), and the door 3 is kept closed by the locking device 13. Even if the inlet 8 allows the granular material to enter the first chamber 5 of the housing 1, the door 3 cannot be opened. Therefore, no granular material can leave the housing 1.

[0080] During the isolation phase, inlet 8 is closed by flap 9 (sealed position PO), and door 3 can be opened. Inlet 8 no longer allows new granular material to enter first chamber 5 of housing 1, and door 3 can be opened. Therefore, even if metering element 4 is subsequently removed, no granular material directly from the hopper via conveying devices 10, 11 can leave housing 1. If desired, if metering element 4 is removed after door 3 is opened, only granular material remaining in storage area 7 will be able to leave housing 1. If applicable, these granular materials remaining in storage area 7 can be discharged through a discharge chute (not shown) to prevent them from falling to the ground.

[0081] The housing 1 comprises a fixed portion 2 and a door 3 that is movable relative to the fixed portion 2, allowing the housing 1 to be opened to access its interior or closed. The door 3 thus adopts an open position PON or a closed position POFF. In the open position PON, the door 3 can be completely removed from the fixed portion 2, as applicable, or can be attached to the fixed portion 2 while maintaining access to the interior of the housing 1. The door 3 is preferably a flat-bottomed cylindrical shape.

[0082] Metering element 4 typically preferably comprises a perforated metering disk that is driven to rotate, preferably by a motor. The metering disk divides the housing into two chambers: a first chamber 5 and a second chamber 6, preferably with different air pressures. The first chamber 5 and the second chamber 6 are preferably substantially cylindrical. Door 3 preferably receives the metering disk, but this example is not limiting.

[0083] The storage area 7 is located in the first chamber 5. It can hold a certain amount of granular material from the hopper. The storage area 7 is located at the bottom of the fixed part 2 of the housing 1.

[0084] An inlet 8 for the granular material is located in the stationary part 2 and opens into the first chamber 5. Preferably, the inlet 8 consists of an opening.

[0085] The baffle 9 is designed to adopt an open position PA, in which the baffle 9 does not cover the inlet 8 or only partially covers the inlet 8, or a sealing position PO, in which the baffle 9 covers the inlet 8. In the open position PA, the baffle 9 allows different flows of particulate material to enter the first chamber 5 through the inlet 8. In the sealing position PO, no particulate material can enter the first chamber 5 through the inlet 8.

[0086] The function of the conveying means 10, 11 is to connect the hopper to the first chamber 5 of the housing 1 and thus to the inlet 8. The conveying means preferably comprises at least one conduit, preferably a lower conduit 10 and an upper conduit 11. The lower conduit 10 leads to the first chamber 5 via the inlet 8. The upper conduit 11 is intended to connect the hopper to the lower conduit 10.

[0087] Hoppers are used to store granular materials such as seeds or inputs in pellet form.

[0088] The selection element 12 can control the flow of particulate material through the inlet 8. The selection element 12 can actually operate the damper 9 so as to move it into the open position PA or the sealing position PO. The selection element 12 itself can adopt one or more first positions P1, in which the open position PA is selected, or a second position, in which the sealing position PO is selected.

[0089] The selector element 12 preferably includes an operating lever 16 connected to the shutter 9 via a fastening device 22. The operating lever 16 is preferably mounted on the fixed portion 2 via a sliding joint formed between a protruding stud 23 of the operating lever 16 and an elongated, curved through-hole 24. The protruding stud 23 is mounted so as to be able to slide within the through-hole 24. The through-hole 24 preferably includes serrations 25' on its inner wall 25, these serrations 25' indicating different first positions P1, for example, as indicated by indicators. The operating lever 16 preferably includes a gripping feature 26 in the form of a handle at its free end 16a for easier gripping. The shutter 9 preferably includes a flat portion 29 at its free end 30, opposite the free end 16a of the operating lever 16. The flat portion 29 is sufficiently large to cover the inlet 8. When the selector element 12 is in the second position, the operating lever 16 can operate the operable portion 21 of the latch 18; otherwise, the operating lever is separated from the operable portion.

[0090] The locking device 13 is configured to lock the door 3 in a locked state E1, in which the door 3 remains in the closed position POFF, as long as the flap 9 is not in the sealing position PO. The locking device 13 also unlocks the door 3 in an unlocked state E2, in which the door 3 can be opened in the open position PON, as long as the flap 9 is in the sealing position PO. Preferably, the locking device 13 includes a first locking element 14 and a second locking element 15. Thus, a dual locking stage is advantageously achieved.

[0091] The position of the first locking element 14 depends on the position of the second locking element 15. Therefore, if the second locking element 15 is in the locked position PV, the first locking element 14 locks the door 3 in the locked state E1. Conversely, if the second locking element 15 is in the unlocked position PDV, the first locking element 14 can unlock the door 3 to the unlocked state E2.

[0092] The position of the second locking element 15 has the unique characteristic of being dependent on the position of the flap 9. Thus, if the flap 9 is in the open position PA, the second locking element 15 is in the locked position PV. Conversely, if the flap 9 is in the sealed position PO, the second locking element 15 is in the unlocked position PDV. Preferably, the second locking element 15 can be operated by a selector element 12 connected to the flap 9. Due to this dependency, the flap 9 must be in the sealed position PO, in other words, the selector element 12 must be in the second position, and thus the hopper and housing 1 must be isolated from each other in order for the door 3 to be opened in the open position PON. Under these conditions, the first locking element 14 can be unlocked.

[0093] When the door 3 is removed, the opening 17 preferably allows access to the interior of the first chamber 5. The opening 17 is preferably circular.

[0094] The latch 18 is preferably movably mounted on the fixed part 2 via a rotation axis 27. In the locked position PV, the latch rests on the projection 20. In the unlocked position PDV, the latch is separated from the projection 20.

[0095] The resetting means 19 preferably comprise a compression spring 28. In the locking position PV, the compression spring 28 presses the latch 18 against the projection 20.

[0096] The protrusions 20 are preferably ribs or teeth.

[0097] The operable portion 21 of the latch 18 is preferably a protrusion, such as a pin or a boss.

[0098] Figure 1 and Figure 2The dosing unit according to the present invention is shown, comprising a housing 1, with a door 3 held closed against the fixed part 2 in a closed position POFF by a locking device 13 in a locked state E1. The selector element 12 is shown in a first position P1. The locking device 13 comprises a first locking element 14 and a second locking element 15. The selector element 12 is in the first position P1, and therefore the second locking element 15 is in the locked position PV. Consequently, since the second locking element 15 is in the locked position PV, the first locking element 14 locks the door 3 in the locked state E1. The latch 18 abuts against the protrusion 20, preventing any further rotation of the door 3 and thus preventing it from switching to the unlocked state E2.

[0099] Figure 3 Partially shown Figure 1 and Figure 2 and is shown in the locking position PV of the second locking element 15 comprising the latch 18 which abuts against the projection 20, thereby preventing any rotation of the door 3 and thus preventing the door 3 from switching to the unlocked state E2. The door 3 remains closed in the closed position POFF.

[0100] Figure 4 and Figure 5 The metering unit of the previous figures is shown and shows that if the selection element 12 is in the first position P1 , the operating lever 16 is separated from the operable portion 21 of the latch 18 , which is not operated.

[0101] Figure 6 The metering unit from the previous figures is shown without the door 3 and with the selection element 12 in the first position P1, so that the flap 9 is in the open position PA. An inlet 8 for the granular material is located in the fixed part 2 and opens into the first chamber 5. The inlet 8 consists of an opening. The flap 9 is in the open position PA, in which it only partially covers the inlet 8.

[0102] Figure 7 Shows a metering unit that is Figure 1 and Figure 2 The metering unit differs in the positions of the selector element 12 and the second locking element 15. The selector element 12 is in the second position P2, and therefore the second locking element 15 is in the unlocked position PDV. Consequently, with the second locking element 15 in the unlocked position PDV, the door 3, which is screwed to the fixed part 2 and in the locked state E1, can be switched from the locked state E1 to the unlocked state E2. The fact that the latch 18 is disengaged from the protrusion 20 allows the door 3 to be rotated and thus switched to the unlocked state E2. In the example shown, this rotation can be performed counterclockwise.

[0103] Figure 8 Partially shown Figure 7and shows that if the selection element 12 is in the second position P2, the operating lever 16 comes into contact with the operable portion 21 of the latch 18 and operates it.

[0104] Figure 9 Shows the metering unit, which is Figure 7 The dosing unit 100 differs in that the door 3 is now in the unlocked state E2 and can therefore be moved from its closed position POFF to the open position PON. In fact, in the unlocked state E2, the door 3 is unscrewed from the fixed part 2 and is no longer attached to it, and can therefore be removed from the fixed part 2 so as to no longer cover the opening 17 and be placed in the open position PON.

[0105] Figure 10 Displays the unit of measure, which is the same as Figure 9 The dosing unit of is different in that the door 3 is removed from the fixed part 2 and no longer covers the opening 17. Furthermore, it can be observed that, given that the selection element 12 is in the second position P2, the flap 9 is thus in the sealing position PO in which it completely covers the inlet 8 with its flat portion 29.

[0106] Figure 11 A portion of the selection element 12 is shown, namely the operating lever 16 and the flap 9. The operating lever 16 is connected to the flap 9 by means of a fastening device 22. The operating lever 16 comprises a gripping device 26 at its free end 16a. The flap 9 comprises a flat portion 29 at its free end 30 opposite the free end 16a of the operating lever 16.

[0107] Figure 12 The dosing unit shows a door 3 and a dosing element 4. The dosing element 4 is in the form of a perforated dosing disc. The door 3 receives the dosing disc, thereby forming a second chamber 6. The door 3 is cylindrical.

[0108] Obviously, the invention is not limited to the embodiments shown and described in the drawings. Modifications are still possible without departing from the scope of protection of the invention, in particular in the composition of the various elements or in the replacement by technically equivalent ones.

Claims

1. A metering unit for a seed drill, comprising at least: - a closed housing (1) comprising at least a fixed part (2) and a door (3) movable between an open position (PON) and a closed position (POFF), - a metering element (4) for a plurality of granular materials, arranged for discrete, single-grain dispensing of the plurality of granular materials, A metering element (4) is arranged in the housing (1) to separate the interior of the housing (1) into a first chamber (5) and a second chamber (6), the first chamber (5) being configured to receive all or part of the plurality of particulate materials at least in the storage area (7), and the second chamber (6) being closed by the door (3) at least in the closed position (POFF). The fixed part (2) of the housing (1) also comprises an inlet (8) for granular material, the inlet for granular material opening into the first chamber (5), associated with the baffle (9), the inlet (8) for granular material being configured to be connected to a conveying device (10, 11) connected to the hopper, The baffle (9) can be operated by a selection element (12) to at least selectively place the baffle (9) in a sealing position (PO) for the inlet (8) for the granular material, in which the baffle (9) seals the inlet (8) for the granular material, or in an open position (PA) for the inlet (8) for the granular material, in which the baffle (9) does not completely seal or partially seals the inlet (8) for the granular material. In the closed position (POFF), the door (3) is locked at least in a locked state (E1) or unlocked in an unlocked state (E2) by at least a locking device (13), The characteristics of the metering unit are: exist The closed position (POFF) of the door (3), the locking device (13) and the selection element (12) are configured as follows: - the door (3) is kept in the locked state (E1) by the locking device (13) as long as the flap (9) is in the open position (PA) or not in the sealed position (PO), and - Operation of the selection element (12) for moving the baffle (9) from the open position (PA) to the sealed position (PO) causes the locking device (13) to operate to allow the door (3) to switch to the unlocked state (E2) or to cause the door (3) to switch to the unlocked state (E2).

2. The metering unit according to claim 1, characterized in that The locking device (13) comprises a first locking element (14) and a second locking element (15); in the closed position (POFF), the door (3) is locked in at least a locked state (E1) or unlocked in an unlocked state (E2) by at least the first locking element (14), and the second locking element (15) is movable between a locked position (PV) and an unlocked position (PDV); and, in the closed position (POFF) of the door (3), the second locking element (15) and the selection element (12) are configured to cooperate with each other so as to: - as long as the flap (9) is in the open position (PA) or not in the sealing position (PO), the second locking element (15) remains in the locked position (PV) to prevent the first locking element (14) from being unlocked, thereby keeping the door (3) in the locked state (E1), and - Operation of the selection element (12) for moving the baffle (9) to the sealing position (PO) causes the second locking element (15) to move from the locked position (PV) to the unlocked position (PDV), allowing the first locking element (14) to be unlocked and allowing the door (3) to switch from the locked state (E1) to the unlocked state (E2).

3. The metering unit according to claim 2, characterized in that In at least one open position (PA) of the shutter (9) corresponding to at least one first position (P1) of the selection element (12), the selection unit (12) is configured not to operate the second locking element (15) so that the second locking element remains in the locking position (PV).

4. The metering unit according to any one of claims 2 to 3, characterized in that In the sealing position (PO) of the shutter (9) corresponding to the second position of the selection element (12), the selection element (12) is configured to operate the second locking element (15) so that the second locking element is in the unlocking position (PDV).

5. The metering unit according to claim 3 or 4, characterized in that The selection element (12) comprises a lever (16) which is mounted so as to be movable on the fixed part (2) of the housing (1), is at least selectively positionable in at least one first position (P1) and in the second position, is mechanically connected to the baffle (9), and preferably comprises gripping means (26) for manual operation of the lever (16).

6. The metering unit according to any one of claims 1 to 5, characterized in that In the closed position (POFF), the door (3) covers the opening (17) of the fixed part (2), and the door (3) is installed so as to be able to be tightened / unscrewed relative to the opening (17) in the closed position (POFF) by means of a first locking element (14) between a locked state (E1) in which the door (3) is tightened and an unlocked state (E2) in which the door (3) is unscrewed.

7. The metering unit according to claim 6, characterized in that The second locking element (15) includes a latch (18) and a protrusion (20) protruding from the periphery of the door (3), the latch being pivotally mounted on the fixed part (2) of the housing (1) between a locked position (PV) and an unlocked position (PDV), the latch being reset by a reset device (19) mounted on the fixed part (2) of the housing (1), the latch (18) being held against the protrusion (20) by the reset device (19) in the locked position (PV) to prevent the door (3) from rotating to keep the door (3) in the locked state (E1), and the latch (18) being separated from the protrusion (20) in the unlocked position (PDV) to allow the door (3) to rotate to allow the door (3) to switch to the unlocked state (E2).

8. The metering unit according to claims 5, 6 and 7, characterized in that The latch (18) comprises an operable portion (21) operable by an operating lever (16), and when moved to the second position, the operating lever (16) is configured to operate the operable portion (21) and exert a force against the reset force of the reset device (19) to pivot the latch (18) to the unlocked position (PDV).

9. A sowing element comprising at least one hopper arranged to receive a plurality of granular materials and connected to a metering unit via a conveying device (10, 11), characterized in that The metering unit is a metering unit according to any one of claims 1 to 8.

10. A seed drill comprising at least one chassis, at least one seeding element being mounted on the at least one chassis, characterized in that: The at least one sowing element is a sowing element according to claim 9.

11. A method for locking / unlocking a metering unit of a seed drill, the seed drill comprising a plurality of granular materials at least in a storage area (7), characterized in that The metering unit is a metering unit according to any one of claims 1 to 8, and the locking / unlocking method comprises: - a locking phase during which, in the closed position (POFF) of the door (3), the flap (9) is in the open position (PA), and the door (3) is held in the locked state (E1) by the locking device (13), and - an isolation phase, during which, in the closed position (POFF) of the door (3), the selection element (12) is operated to move the baffle (9) from the open position (PA) to the sealed position (PO), causing the locking device (13) to operate to allow the door (3) to switch to the unlocked state (E2) or to cause the door (3) to switch to the unlocked state (E2).

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