Pneumatic seed metering device for precision seeder.

Description

1 / 26 Pneumatic seed metering device for precision seeder.

[0001] The present invention relates to the technical field of agricultural machinery, more specifically those related to seeding and, even more specifically, to precision seeders that place seeds individually in the field at regular intervals. In particular, the present invention relates to a pneumatic metering device, operating with negative pressure, for the individualized distribution of grains in rows as the seeder advances. PREVIOUS TECHNIQUE AND PROBLEMS TO BE SOLVED

[0002] Pneumatic seeders are widely known and applied devices in modern agriculture, designed to ensure precise and uniform seeding of seeds such as corn, soybeans, and sunflowers, among many others. Over time, they have evolved, improving their performance and characteristics, and a wide variety of these devices are currently available.

[0003] Although there are several types of dosers in terms of operation and drive principle, with regard to the technique related to the object of the present invention, these devices operate with a suction mechanism, which generates vacuum pressure, and rotating discs with alveoli, where the grains are individually housed for distribution.

[0004] The vacuum is generated by a pump or fan connected to the metering device, creating a pressure differential that sucks the seeds into the cells of the plate as the disc rotates. Each cell is designed with a specific size and shape to accommodate an individual seed, ensuring that each one is placed in the sowing furrow at the stipulated speed and frequency.

[0005] The development of this equipment has been constantly advancing to improve the accuracy of grain dosing and minimize variability in the distance between seeds, which Petition 870250085430, dated 09 / 22 / 2025, pp. 61 / 108 2 / 26 is essential to maximize crop productivity, since uniform sowing promotes homogeneous crop growth, optimizing the use of resources such as water, nutrients, and sunlight.

[0006] One of the main characteristics of these implements is the versatility and wide range of adjustments and configurations that allow the seeders to be adapted to the most diverse operating and working conditions, for carrying out sowing campaigns of different crops.

[0007] In this sense, most seeders allow interchangeability of seed plates, leveling devices, disc rotation speed and grain feed rate from the hopper to the metering chamber, among many other possible adjustments.

[0008] However, a major problem related to this aspect lies in the difficulty of making configuration changes and the need, in most cases, to disassemble the equipment and replace components.

[0009] As is known, agricultural machines that use these implements comprise a plurality of seeding trains, which contain various tools in addition to the metering devices, arranged in rows. This implies the need to manipulate the mechanisms in confined and difficult spaces.

[0010] Furthermore, many of the modifications are based on empirical tests and field trials of the metering devices' operation in the soil where sowing will take place, so adjustments often need to be made in situ, during the sowing process. In this sense, it is desirable that the metering device adjustment elements be convenient, easily accessible, and simple to operate, as well as that the replacement parts be equally easy to replace.

[0011] For example, one of the most common calibrations is adjusting the seed level inside the metering chamber. Depending on the Petition 870250085430, dated 09 / 22 / 2025, p. 62 / 108 3 / 26 Depending on the grain size to be distributed and the rotation speed of the seed plate, it may be more convenient to have a higher or lower seed level within the chamber. Some currently known metering devices include adjustment gates that partially restrict the seed inlet opening in the chamber in order to maintain a stable flow that maintains a determined grain level. However, these gates are often difficult to access and configure. Some metering devices include an internal plate that blocks the seed inlet orifice and can be moved along a guide to adjust the desired opening, fixing the position by adjusting a screw or nut. Considering that this type of machine requires the seeding units to operate as uniformly as possible, it is complex to determine the same set point for all metering devices, which can lead to metering errors or uneven distribution between rows.Although there are implementations that overcome this disadvantage by replacing the continuous guide with predetermined grooves, where the same defined positions can be established for all units, having to disassemble the dispenser to perform the configuration is an extremely laborious task for such a simple adjustment.

[0012] Other metering devices, such as the one described in document US20170311535A1, allow this adjustment without the need to open the metering device, using a lever accessible from the outside of the housing. However, the implementation of the metering device adjustment gate described in this prior art document presents certain disadvantages. Firstly, the sliding up-down mechanism of the gate tends to jam and hinder movement. Furthermore, the positioning lever is located at the rear of the metering device, next to the seed inlet duct, which is a difficult-to-access and visible area. Both defects, in Petition 870250085430, dated 09 / 22 / 2025, page 63 / 108 The 4 / 26 assembly makes operating this implement a difficult and impractical task.

[0013] However, to perform some configurations and adjustments, it may eventually be essential to open the dispenser. Before doing so, the equipment must be emptied, as it is usually loaded with seeds.

[0014] For this purpose, some known metering devices have purge orifices to empty the seed chambers. Current equipment generally employs mechanisms such as that seen in the figures of document US2017245421, which consists of a plug that seals an orifice, held in place by an elastic element that exerts pressure to fix the closed position. When the metering device needs to be purged, a force is exerted on the elastic element and the plug is moved to one side, uncovering the orifice and allowing the seeds to be discharged. However, this implementation is disadvantageous because the discharge orifice is usually a small opening located in the feed duct or in a lower portion of the seed chamber, but is not sufficient to completely discharge the equipment.In this way, it is necessary to insert a tool or utensil to dig inside the chamber, with the associated risk of damaging other components of the metering device or not extracting all the seeds, which means that when the equipment is opened, they will fall to the ground and be wasted. Another disadvantage of this solution lies in the way the seeds are discharged through these holes, which are simply openings through which the grains fall by gravity, directly downwards. This makes it extremely difficult to place a container to recover the material contained in the chamber for later reuse, given that the entire seeding train is located immediately below the metering devices. Thus, a large part of the material contained in the metering devices is wasted, which translates linearly into financial loss for the farmer. Petition 870250085430, dated 09 / 22 / 2025, pp. 64 / 108 5 / 26

[0015] Replacing interchangeable pneumatic metering components is another frequent problem with their use. As is known, this type of equipment works with metering plates comprising a plurality of holes arranged in rows to accommodate the seeds to be distributed as the plate rotates. These plates are usually specific to a type of crop or to a series of determined crop types, and therefore, when configuring the machine to vary the type of seed to be sown, it is often necessary to replace the plates and leveling elements.

[0016] Although equipment with quick-release plates and levelers, which eliminate the need for external tools for assembling and disassembling implements, are currently known, such as, for example, the metering device described in document US2013192504A1, frequently, in these devices, the leveler assembly is coupled to the seed chamber, in the half that remains fixed mounted on the seeding train.

[0017] This makes handling, maintenance and replacement of parts difficult, since the maneuvering space in this area is considerably reduced, making the work complicated and heavy, even requiring the disassembly of the doser if the task requires a finer or more precise intervention.

[0018] Similarly, when replacing components worn out by use, such as vacuum chamber seals or seed ejection mechanisms, the individual replacement of parts can consume valuable time. Furthermore, with respect to replacing individual seals, there is the possibility of positioning errors, resulting in losses or fluctuations in the metering vacuum pressure due to chamber seal failures. OBJECT OF THE INVENTION

[0019] The object of the present invention is, therefore, to provide a dispenser that overcomes the shortcomings of the prior art, with a Petition 870250085430, dated 09 / 22 / 2025, pages 65 / 108 6 / 26 simple and practical design for operation. In particular, a pneumatic seed metering system is provided for precision seeders, easy to set up and adjust in situ, minimizing material losses caused by maintenance tasks and optimizing equipment setup times for specific sowing campaigns.

[0020] It is also an object of the present invention to provide a pneumatic seed metering device comprising multiple inspection and control points to monitor the correct operation of the equipment. Similarly, the object of the present invention is to provide a pneumatic seed metering device for precision seeders, comprising interchangeable components that do not require additional tools for assembly or disassembly, facilitating maintenance tasks, reducing installation errors and reducing setup times. BRIEF DESCRIPTION OF THE FIGURES

[0021] Figure 1 is a front perspective view of the pneumatic seed metering device for precision seeders, according to an embodiment of the present invention.

[0022] Figure 2 is a front perspective view of the pneumatic seed metering device for precision seeders, according to an embodiment of the present invention.

[0023] Figure 3A is a view of the interior of the vacuum chamber of the pneumatic seed metering device for precision seeders, according to an embodiment of the present invention.

[0024] Figure 3B is a view of the interior of the vacuum chamber of the pneumatic seed metering device for precision seeders, according to an embodiment of the present invention, with a seed plate and a leveling assembly coupled.

[0025] Figure 3C is an external view of the vacuum chamber of the pneumatic seed metering device for precision seeders, according to an embodiment of the present invention.

[0026] Figure 3D is an external view of the vacuum chamber of Petition 870250085430, dated 09 / 22 / 2025, pp. 66 / 108 Pneumatic seed metering device 7 / 26 for precision seeders, illustrating the first position of an operating mode according to an embodiment of the present invention.

[0027] Figure 3E is an external view of the vacuum chamber of the pneumatic seed metering device for precision seeders, illustrating the second position of an operating mode according to an embodiment of the present invention.

[0028] Figure 4A is an internal view of the seed chamber of the pneumatic seed metering device for precision seeders, according to an embodiment of the present invention, with the adjustment flap and the purge gate in a first position.

[0029] Figure 4B is an internal view of the seed chamber of the pneumatic seed metering device for precision seeders, according to an embodiment of the present invention, with the adjustment flap and the purge gate in a second position.

[0030] Figure 4C is an external view of the seed chamber of the pneumatic seed metering device for precision seeders, according to an embodiment of the present invention.

[0031] Figure 5 is a detailed view of the sealing support of the pneumatic seed metering device for precision seeders, according to an embodiment of the present invention.

[0032] Figure 6A is a detailed view of an alternative sealing support for the pneumatic seed metering device for precision seeders, according to another embodiment of the present invention.

[0033] Figure 6B is an exploded view of the alternative sealing support of the pneumatic seed metering device for precision seeders, according to the embodiment illustrated in Figure 6A.

[0034] Figure 7A is a detailed view of an alternative sealing support for the pneumatic seed metering device for precision seeders, according to another embodiment of the present invention.

[0035] Figure 7B is an exploded view of the sealing support. Petition 870250085430, dated 09 / 22 / 2025, pp. 67 / 108 8 / 26 alternative pneumatic seed metering device for precision seeders, as illustrated in Figure 7A. DETAILED DESCRIPTION OF THE INVENTION

[0036] The pneumatic seed metering device (10) for precision seeders of the present invention, as illustrated in the attached Figures 1 and 2, has a plastic housing (20) mounted on a structure (21) comprising the elements for anchoring and connecting the equipment to the seeding train of a seeding machine.

[0037] The plastic casing (20) is divided into two halves, a first half, fixed to the seeding train, which defines a seed chamber (40); and a second half, formed by a removable lid, which defines a vacuum chamber (30).

[0038] As can be seen in Figure 1, which illustrates the front of the metering device (10), the arrangement of the equipment on the structure (21) anchored to the seeding train can be observed. At the top, a conduit (37) can be seen, corresponding to the suction opening, where the vacuum source hose is coupled. This pneumatic connection arrangement allows all the metering devices (10) arranged in the rows of the seeding machine to be connected from a more convenient location, where the hoses do not suffer excessive bending or interfere with the handling of the equipment. Thus, suction is produced from the aforementioned inlet (37) and through an internal circuit of the metering device (10), resulting in a much more compact design of the equipment.

[0039] On the front of the dispenser (10), there is an inspection cover (39), which allows access to the interior of the aforementioned pneumatic circuit, to inspect it and ensure that there are no obstructions, dirt or other foreign bodies. In this way, the condition of the pneumatic circuit can be checked without the need to disconnect the vacuum hose from the suction opening (37) or disassemble the dispenser (10). Petition 870250085430, dated 09 / 22 / 2025, pages 68 / 108 9 / 26

[0040] In the same area, located in the center of the front face, is the transmission coupling (38), responsible for transmitting the rotary motion to the interior of the doser. According to the illustrated embodiment, the coupling (38) is shown as a crown coupling, although other connectors may alternatively be used to connect electric motors, flexible gearboxes, among other control elements.

[0041] On the other hand, on the rear part, illustrated in Figure 2, it can be observed that the structure (21), in addition to the connection elements (24) to the seeding train, also includes the means to receive a grain feed hopper (25), from where the seeds to be distributed by the metering device (10) are fed.

[0042] Moving into the metering device, the half corresponding to the vacuum chamber (30), shown in detail in Figure 3A, comprises an orifice (301) corresponding to the internal pneumatic vacuum duct. Towards the center of the chamber (30) itself, there is a shaft (31) that is moved by the drive element connected to the transmission coupling (38) on the outside. Said shaft (31) transmits the rotation to a drive disc (311) which is responsible for rotating the seed plate (32), illustrated in Figure 3B, to transport the seeds, in the alveoli (321), towards the discharge zone.

[0043] Preferably, the shaft (31) has a slot (312) that allows the plate (32) to be fixed to said shaft (31) and its seating against the drive disc (311) by means of a sliding lock (322), without the need for external fastening elements.

[0044] A floating leveling assembly (36) is located on the seed plate (32). The mounting of the leveling assembly (36) on the removable cover comprising the vacuum chamber (30) represents a novelty in the design of the present metering device (10). Petition 870250085430, dated 09 / 22 / 2025, pp. 69 / 108 10 / 26 because it allows complete removal of the vacuum chamber (30), with all interchangeable components inside, which facilitates maintenance tasks, eliminating the need to intervene in the part of the equipment that remains attached to the seeder.

[0045] Returning to Figure 3A, the vacuum chamber (30) includes, in its upper portion, two snap-fit ​​clamps (303), each with a pointed tip, whose inclination is interrupted by a cutout that serves as a lock. In this way, the movement is limited only in the direction of insertion, allowing the said clamps (303) to be simply inserted under pressure into the leveling assembly (36) and remain fixed after the cutout zone has passed through the engagement.

[0046] Another of the main advantages of the present pneumatic doser (10) lies in a modular support (33) that is mounted in the vacuum chamber (30) and comprises a flexible seal (34) and the solid particle ejector mechanism (35).

[0047] This modular support (33) is illustrated in detail in Figure 5, and it can be observed that it comprises a plurality of anchor points (331) for connection to the vacuum chamber body (30). In the illustrated embodiment, the anchor points (331) comprise screws, although they may alternatively be replaced by pressure pins, clips, clamps, among others.

[0048] The flexible seal (34) comes into contact with the seed plate (32) to form a sealed vacuum zone (302) enclosed within it.

[0049] In particular, the flexible seal (34) has a semicircular shape, comprising a larger perimeter (342) that follows the contour of the vacuum chamber housing (30) and completely covers the line of alveoli (321) of the seed plate (32), interrupted by a radial section (341) that extends inward, and a smaller perimeter (343) that closes the entire contour of the seal (34). Preferably, this seal (34) Petition 870250085430, dated 09 / 22 / 2025, pp. 70 / 108 11 / 26 is made of an elastomeric material that gives it the flexibility needed to copy the surface of the seed plate and maintain the watertightness of the delimited zone (302).

[0050] As mentioned earlier, the zone delimited within the flexible seal (34) is the vacuum zone (302), i.e., the portion of the chamber (30) that is under the influence of the vacuum source, which generates the negative working pressure. Consequently, the zone defined by the smaller perimeter (343), the radial section (341) and the chamber housing (30) is outside the effects of suction and, finally, is at normal atmospheric pressure. This zone is then defined as the atmospheric pressure zone (304).

[0051] When, in its direction of rotation, a cell (321) of the metering plate (32) occupied by a seed passes through the radial segment (341), the said cell ceases to be under the influence of vacuum pressure and, finally, the grain ceases to be pressed against the plate (32), so that it falls by gravity towards the discharge zone.

[0052] The unblocking mechanism (35) is located in the atmospheric pressure zone (304), which ensures that no solid particles, such as grains or dirt, become improperly trapped in the said alveoli (321) of the plate (32). This unblocking mechanism consists of an articulated arm (351) containing, at one end, a wheel (352) with a plurality of protrusions (353) that penetrate the said alveoli (321) of the metering plate (32) to expel trapped particles.

[0053] The advantage of having both the seal (34) and the unblocking mechanism (35) on the modular support (33) reduces the replacement time of said components and minimizes errors due to incorrect positioning of the same, since the support has a unique mounting position that does not allow incorrect positioning. Petition 870250085430, dated 09 / 22 / 2025, pp. 71 / 108 12 / 26

[0054] Additionally, another embodiment of the present invention comprises the implementation of another type of modular support (50) with the implementation of a rigid seal (54), as seen in detail in Figures 6A and 6B.

[0055] In this variant, a modular support (50) is provided which, analogously to the support (33) of the previous embodiment, comprises a plurality of anchoring points (501) for connection to the vacuum chamber body (30), as shown in detail in Figure 6B. In the illustrated embodiment, the anchoring points (501) comprise screws, although they may alternatively be replaced by pressure pins, clips, clamps, among others. Similarly, this embodiment also comprises a de-blocking mechanism (55), similar to that described above. This de-blocking mechanism is formed by an articulated arm (551) which contains at one end a wheel (552) with a plurality of protrusions (553) that penetrate the said alveoli (321) of the dosing plate (32) to expel trapped particles.

[0056] The rigid seal (54), in turn, has a low coefficient of friction, which produces low frictional resistance to the rotary motion of the plate (32), resulting in less torque required to rotate the mechanism. Preferably, the rigid seal (54) is made of acetal resin or another low coefficient of friction polymer that exhibits the characteristics highlighted above.

[0057] An advantageous feature of this variant is that, in order to maintain and guarantee the contact of the rigid seal (54) against the seed plate (32), inside said seal (54) and linked to it, actuation arms (544) are arranged which produce an axially actuated orthoplanar spring effect.

[0058] The operating principle of the drive arms (544) is governed by the action of fork-shaped levers (545), which deform orthogonally, leaving their position of Petition 870250085430, dated 09 / 22 / 2025, pp. 72 / 108 13 / 26 coplanar rest when subjected to stress. In this way, the said drive arms (544) exert the axial force to press the seal (54) against the metering plate (32), ensuring the tightness of the vacuum zone.

[0059] These arms (544), as explained, are located at one end, integrally connected to the rigid seal (54) and, at the opposite end, joined to the assembly (50) by means of the fixing points (546) corresponding to each one. Preferably, the fixing points comprise two holes, one to house a removable element, such as a screw, a pin, clip, clamp or similar, which fits against the associated connection points (503) arranged on the support (50); and a second hole to receive a guide fixing element, such as a fixed screw, pin or similar, included in said connection points (503), which prevent angular displacement of the arms (544) and, consequently, of the seal (54). In this way, it is ensured that the rigid seal (54) remains constantly in the ideal operating position, preventing loss of tightness and the production of suction defects.Similar to the flexible seal (34) of the previous embodiment, the rigid seal (54) comprises a semicircular shape geometry, comprising a larger perimeter (542), which follows the contour of the vacuum chamber housing (30) and completely covers the line of alveoli (321) of the seed plate (32), interrupted by a radial section (541), which extends inwards, and a smaller perimeter (543), which closes the entire contour of the seal (54).

[0060] It should be noted that, as the geometry of the rigid seal (54) is not symmetrical along its contour, the actuating arms (544) are configured to exert a differential force in order to maintain a constant and uniform pressure of the seal (54) against the metering plate (32). Furthermore, this characteristic of the differentiated actuating arms (544) allows for dynamic compensation of possible inclinations of the Petition 870250085430, dated 09 / 22 / 2025, pp. 73 / 108 14 / 26 plate surface (32) due to deviations with respect to perpendicularity of axis (31).

[0061] According to the embodiment illustrated in Figures 6A and 6B, the three actuating arms (544a; 544b and 544c) comprise different lever lengths (545), calibrated to adjust the compression as a function of their distance from the outer contour of the rigid seal (54).

[0062] It can be seen in detail that the actuating arm (544c) has a lever length (545) greater than that of arm (544a) and even greater than that of arm (544b). As the actuating arm (544c) is closer to the outer contour, being located in the section where the rigid seal (54) has the cutout, by means of the smaller perimeter (543), to define the atmospheric pressure zone (304), the pressure to be exerted is less than that of its counterparts, so that a greater lever length (545) offers greater elasticity to the axial movement. On the other hand, the actuating arm (544b) is located at a greater radial distance from the outer contour, compared to arm (544c), and finally has a shorter lever length (545), which gives it greater rigidity and resistance to axial movement, i.e., it exerts a greater compressive force.In turn, the drive arm (544a) behaves similarly to its counterparts, with an intermediate lever length (545), which corresponds to the compression force applied to the rigid seal (54) against the metering plate (32).

[0063] The geometry and arrangement, as well as the number, of the actuating arms (544) of the rigid seal (54) may vary depending on the configuration and characteristics of the doser in which they are mounted.

[0064] An elastic membrane (53) is disposed between the rigid seal assembly (54) with the actuating arms (544) and the support (50). This elastic membrane (53) has a contour that imitates and follows the silhouette of the rigid seal (54). Petition 870250085430, dated 09 / 22 / 2025, pp. 74 / 108 15 / 26

[0065] The rigid seal (54) remains floating due to the drive arms (544). When the metering device (10) is in operation, a vacuum is created inside the chamber (30) and the seal (54) is compressed against the metering plate (32). Due to the same vacuum effect, the flexible membrane (53) deforms and adheres to the underside of the rigid seal (54), completely closing the vacuum zone (302). Thus, the flexible membrane (53) seals the small gap that exists between the rigid seal (54) and the support (50).

[0066] Preferably, the flexible membrane (53) is composed of a material of low rigidity and high elasticity, allowing it to deform under the vacuum generated in the chamber (30). Among the preferred materials for the manufacture of said flexible membrane (53) are, among others, although not limited to them, the following: silicone, NBR or similar.

[0067] As seen in Figure 6B, the elastic membrane (53) also comprises a plurality of holes (531) which conveniently coincide with the location of the attachment points (503) of the support (50).

[0068] To keep the membrane (53) pressed against the support (50) and fixed to the rigid seal (54), there is a rigid retaining plate (52) that holds it in place. This retaining plate (52) acts as an interface between the membrane (53) and the seal (54) and restricts flexibility, allowing only the protruding portion of the plate to deform. This portion adheres to the rigid seal (54) due to the vacuum action during operation.

[0069] It can be observed that the said plate (52) also comprises corresponding holes (521) to accommodate the fastening element that holds the entire assembly composed of the seal (54), the retaining plate (52), the elastic membrane (53) and the support (50) together. Preferably, the holes (521) in the retaining plate (52) have an additional passage for the fastening element to guide the connection points (503), which Petition 870250085430, dated 09 / 22 / 2025, pp. 75 / 108 16 / 26 prevents angular rotation of the drive arms (544). The assembled unit can be clearly seen in Figure 6A.

[0070] Another alternative can be seen in Figures 7A and 7B. Similar to the previous version, this variant provides for another type of modular support (60), also with the implementation of a rigid seal (64).

[0071] In this alternative, a modular support (60) is provided which, analogously to the support (33) and the support (50) of the previous embodiments, comprises a plurality of anchoring points (601) for connection to the vacuum chamber body (30), as seen in detail in Figure 7B. In the illustrated embodiment, the anchoring points (601) comprise screws, although they may alternatively be replaced by pressure pins, clips, clamps or other fasteners. Similarly, this embodiment also comprises a de-blocking mechanism (65), similar to that described above. This de-blocking mechanism is formed by an articulated arm (651) which contains, at one end, a wheel (652) with a plurality of protrusions (653) that penetrate the alveoli (321) of the dosing plate (32) to expel trapped particles.

[0072] The rigid seal (64), in turn, has a low coefficient of friction, which produces low frictional resistance to the rotary motion of the plate (32), resulting in less torque required to rotate the mechanism. Preferably, the rigid seal (64) is made of acetal resin or another low coefficient of friction polymer that exhibits the characteristics highlighted above.

[0073] The geometry of the seal (64) may comprise a contour analogous to that described in previous embodiments, namely, a semicircular silhouette comprising a larger perimeter (642), which follows the contour of the vacuum chamber housing (30) and completely covers the line of alveoli (321) of the seed plate (32), interrupted by a radial section (641), which extends Petition 870250085430, dated 09 / 22 / 2025, pp. 76 / 108 17 / 26 inwards, and a smaller perimeter (643), which closes the entire perimeter of the fence.

[0074] To maintain and ensure the contact of the rigid seal (64) against the seed plate (32), an axially actuated orthoplanar spring (61) is disposed inside said seal (64) and connected to it. This spring (61), as observed in greater detail in Figure 7B, has an outer contour (611) that imitates and follows the silhouette of the rigid seal (64); an inner perimeter (612), connected to the outer contour (611) by a plurality of radii (613); and a center (614), comprising a central orifice (615), through which the shaft (31) passes.

[0075] Cut in the central hole (615), there is at least one notch (616). This at least one notch (616) fits into screws or fastening devices, connected to the vacuum chamber (30), and which have the function of restricting the angular movement of the spring (61) and, finally, of the rigid seal (64).

[0076] Following the aforementioned center (614), a plurality of actuating arms (617) extend radially, responsible for applying the axial force to press the seal (64) against the metering plate (62), as well as providing angular rigidity. The actuating arms (617) connect the center (614), which remains fixed both axially and angularly, to the inner perimeter (612), which distributes and transmits, through the plurality of radii (613), the compressive stress to the outer contour (611) and, finally, to the rigid seal (64). The operating principle of the actuating arms (617) is governed by the action of fork-shaped levers (618), which deform orthogonally, abandoning the coplanar rest position when subjected to stress.

[0077] It should be noted that, as the geometry of the rigid seal (64) is not symmetrical along its contour, the actuating arms (617) are configured to exert a differential tension in order to maintain a constant and uniform pressure of the Petition 870250085430, dated 09 / 22 / 2025, pp. 77 / 108 18 / 26 seal (64) against the metering plate (32). Similarly, this feature of the differentiated drive arms (617) allows dynamic compensation for possible inclinations of the plate surface (32) due to deviations with respect to the perpendicular of the axis (31).

[0078] According to the embodiment variant illustrated in Figures 7A and 7B, the orthoplanar spring (61) comprises three actuating arms (617a; 617b and 617c), which in turn comprise different lever lengths (618), calibrated to adjust the compression as a function of their distance from the outer contour (611), connected to the rigid seal (64).

[0079] It can be seen in detail that the actuating arm (617c) has a lever length (618) greater than that of arm (617a) and even greater than that of arm (617b). As the actuating arm (617c) is closer to the outer contour (611), being located in the section where the rigid seal (64) has the cutout to define the atmospheric pressure zone (304), the pressure to be exerted is less than that of its counterparts, so that a greater lever length (618) offers greater elasticity to the axial movement. On the other hand, the actuating arm (617b) is located at a greater radial distance from the outer contour (611), compared to arm (617c), and finally has a shorter lever length (618), which gives it greater rigidity and resistance to axial movement, i.e., it exerts a greater compressive force.In turn, the drive arm (617a) behaves similarly to its counterparts, with an intermediate lever length (618), which corresponds to the compression force applied to the rigid seal (64) against the metering plate (32).

[0080] The geometry and arrangement, as well as the number, of the actuating arms (617) of the orthoplanar spring (61) may vary depending on the configuration and characteristics of the doser in which they are mounted. Petition 870250085430, dated 09 / 22 / 2025, pp. 78 / 108 19 / 26

[0081] An elastic membrane (63) is disposed between the rigid sealing assembly (64) with the orthoplanar spring (61) and the support (60). Said elastic membrane (63) has a contour that imitates and follows the silhouette of the rigid seal (64).

[0082] The rigid seal (64) is kept floating by the spring (61). When the metering device (10) is in operation, a vacuum is created inside the chamber (30) and the seal (64) is compressed against the metering plate (32). Due to the same vacuum effect, the flexible membrane (63) deforms and adheres to the underside of the rigid seal (64), completely closing the vacuum zone (302). Thus, the flexible membrane (63) seals the small gap that exists between the rigid seal (64) and the support (60).

[0083] Preferably, the flexible membrane (63) is made of a material with low stiffness and high elasticity, allowing it to deform under the effects of the vacuum generated in the chamber (30). Among the preferred materials for the manufacture of said flexible membrane (63) are, although not limited to them, the following: silicone, NBR or similar.

[0084] As observed in Figure 7B, the elastic membrane (63) also comprises a plurality of holes (631) that conveniently coincide with the location of the joining points (601) of the support (60).

[0085] To keep the membrane (63) pressed against the support (60) and fixed to the rigid seal (64), a rigid retaining plate (62) is provided, which keeps it fixed. This retaining plate (62) serves as an interface between the membrane (63) and the seal (64) and restricts flexibility, allowing only the protruding portion of the plate to deform, which is the portion that adheres to the rigid seal (64) due to the vacuum action during operation.

[0086] It can be observed that the said plate (62) also includes the corresponding holes (621) for housing the fastening element that holds the support (50) attached to the vacuum chamber (30). Additionally, the fastening plate (62) also has Petition 870250085430, dated 09 / 22 / 2025, pp. 79 / 108 20 / 26 holes (622) to house fastening elements (619) that hold the spring (61) together and stable. As can be seen more clearly in Figure 7A, the fastening elements (619) hold the spring (61) together with the fixing plate (62), from the center (614).

[0087] The complete vacuum chamber (30), as provided above, can be easily assembled and disassembled from the half of the metering device (10) comprising the seed chamber (40). As can be seen in Figure 3C, which shows the outer face of said vacuum chamber (30), by removing a cover (22) from the housing (20), a lever (26) is revealed which can exert pressure on the linear spring (305), as illustrated in Figures 3D and 3E, which functions as a link to keep both halves, i.e., the vacuum chambers (30) and the seed chamber (40), together.

[0088] For this purpose, the said seed chamber (40) comprises, on the upper part of its inner face, two locking clamps (401), each of which has a pointed tip, the inclination of which is interrupted by a cutout that serves as a lock, as can be seen in Figures 4A and 4B. In this way, the movement is limited only in the direction of insertion, allowing the said clamps (401) to be simply introduced with pressure into the vacuum chamber (30) and remain fixed once the cutout zone has passed through the lock. To open the pneumatic metering device (10) and remove the cover (22) from the housing (20), a lever is pulled to reveal the linear spring (305) and, by applying slight pressure to its ends, the locking clamps (401) are released from the vacuum chamber (40).In this way, the interior of the doser (10) can be accessed practically and easily, without the need for additional tools to disassemble the equipment, perform the necessary work on the internal components and quickly reassemble both halves.

[0089] As shown in Figure 4C, an opening of Petition 870250085430, dated 09 / 22 / 2025, pages 80 / 108 21 / 26 feed (41) is provided on the outside of the seed chamber (40), through which the seeds to be metered enter, coming from a storage hopper. The seed level inside the chamber (40) is controlled by an adjustment gate (42) located in the feed opening (41). This adjustment gate (42) is pivoting in relation to a connection point (421). This feature, combined with its location on the outside of the seed chamber (40), makes the adjustment gate (42) less prone to jamming and facilitates its operation. Similarly, its adjustment is carried out from the front of the metering device (10) and from the end furthest from the seeder body, which is the sector with the easiest access and mobility. Thus, the position of the adjustment gate (42) can be discreetly modified by means of an adjustment pin (422) that is placed alternately in a series of grooves (423), as best seen in Figures 4A-B.

[0090] Below the feed opening (41), there is a purge opening (43) to empty the contents of the chamber (40). Occasionally, to perform adjustment or maintenance tasks, it is necessary to open the metering device (10) and, for this purpose, empty the contents of the seeds housed inside. For this purpose, the purge opening (43) comprises a hinged gate (44) that opens in the discharge direction, as seen in detail in Figure 4C. In this way, the hinged gate (44) not only releases the passage of seeds to the outside of the metering device, but also allows the user to manually regulate the speed of grain output, increasing or decreasing the degree of opening. In addition, the said hinged gate (44) covers the entire lower part of the seed chamber (40), so that, when opened, all the seeds contained in said chamber (40) fall by gravity towards the purge opening (43).

[0091] Similarly, the purge opening (43) comprises a channeling ramp (431) that directs the purged seeds Petition 870250085430, dated 09 / 22 / 2025, pp. 81 / 108 22 / 26 in a single direction, towards one side of the seeding train. In this way, the user can easily position a container at the outlet of said purge opening (43) to collect the extracted seeds, preventing them from falling to the ground and being wasted.

[0092] Another advantage of the present doser (10) is its various inspection openings, which allow controlling the operation of the equipment and inspecting its internal mechanisms without the need to disassemble or open it completely.

[0093] At the top, there is an inspection cover (46), which allows inspection of the seed train circulating housed in the alveoli (321) of the metering plate (32) in the initial phase of its path. That is, one can observe, for example, the action of the suction force through the plate, the positioning of the grains in the alveoli (321) and the performance of the leveling assembly (36).

[0094] The metering device (10) comprises an outlet duct (45), located in the discharge zone, through which the grains are expelled for their sequential distribution in the soil. Just above this outlet duct (45), on the outside, there is an inspection hatch (47) that allows inspection of the seed distribution before entering the said duct (45).

[0095] Through this inspection hatch (47), it is possible to observe the behavior of the grains in the discharge zone, that is, what happens to the seeds that move in the alveoli (321) of the metering plate (32) as they pass from the vacuum zone (302) to the atmospheric pressure zone (304), in addition to the performance of the unblocking mechanism (35).

[0096] In a preferred embodiment, the inspection hatch (47) is made of transparent plastic, so that the interior of the dispenser can be observed through said closed hatch (47).

[0097] Regarding the interior, as can be seen Petition 870250085430, dated 09 / 22 / 2025, pp. 82 / 108 23 / 26 in Figures 4A and 4B, the seed chamber comprises a main space, which corresponds to a seed reservoir (48), where the grains that enter through the feed opening (41) are accumulated. In this space, the grains are moved by the metering plate (32) and, by the action of the vacuum, are lodged in the alveoli (321), which direct them to the outlet duct (45).

[0098] As explained, the seed level inside the reservoir (48) is regulated by the regulating gate (42). Depending on the type of seeds to be dosed, it may be convenient for the reservoir (48) to be more or less full. In this way, by alternating the position of the adjustment pin (422) between the different grooves (423), the height and degree of opening of said gate (42) can be modified.

[0099] In a preferred embodiment, the adjustment pin (422) has a spring-loaded pull mechanism which, when pulled, releases the pin (422) so that it can move and change position, and, when released, i.e., when the spring returns to the rest position, the pull engages with the selected groove (423), fixing the position. In this way, the risk of inadvertent misalignments during sowing, caused by movements or vibrations of the machine as it moves across the field, is avoided.

[00100] In Figure 4B, as already explained, it can be observed that the hinged gate (44) covers the entire lower zone of the seed reservoir (48). Thus, when the said gate (44) is opened, as shown in Figure 4A, all the grains are extracted from the metering device (10), making it unnecessary to use additional tools or excavations inside the seed chamber (40) to remove the retained seeds.

[00101] At the top of the inner part of the seed chamber (40), near the suction opening (37), there is an orifice (402) which corresponds to the internal pneumatic vacuum circuit and is complementary to the analogous orifice (301) located in the vacuum chamber (30). When both halves of the metering device (10) Petition 870250085430, dated 09 / 22 / 2025, pp. 83 / 108 24 / 26 are connected, these holes (301; 402) face each other and seal, forming a passage that connects the suction opening (37), from where the vacuum pressure is exerted, and the vacuum chamber itself (30).

[00102] In turn, on the lower side, the outlet duct (45) can be observed, through which the seeds that fall from the plate (32) descend. Commonly, in this part, pneumatic metering devices are usually coupled to a downpipe, which directs the grains directly to the furrow opened in the soil for sowing.

[00103] As is known, due to the action of the negative pressure generated by the vacuum source and the rotation of the metering plate (32), the grains accumulated in the seed reservoir (48) progressively settle into the alveoli (321) of said plate (32). Frequently, more than one grain is sucked by the vacuum pressure through a single alveolus (321), resulting in multiple occupations. To avoid double or multiple distribution, individualization elements are available, such as the leveling assembly (36). These implements remove overlapping grains and help ensure that each alveolus (321) contains only one seed.

[00104] However, once the seed train passes through the leveling assembly area (36) and removes the excess grains, the loose grains bounce freely inside the seed chamber (40). The grains loosened by the leveling assembly (36) and removed from the seed plate drag (32) may eventually fall into the outlet duct (45), resulting in an undesirable overdosing. To avoid this, inside the seed chamber (40), before entering the outlet duct (45), the present metering device (10) comprises a regulating flap (49) that controls the passage of excess seeds towards said duct (45), thus preventing overdose.

[00105] This regulating tab (49) comprises an L-shaped plate, which can switch between a first position, less Petition 870250085430, dated 09 / 22 / 2025, pp. 84 / 108 25 / 26 restrictive, and a second position, which further restricts the space available for the passage of seeds towards the outlet duct (45). The selection between the first and second position is made depending on the crop to be dosed. On the one hand, in the first, less restrictive position, the flap (49) is prevented from affecting the passage of larger grains propelled by the seed plate (32), causing them to fall from the alveoli (321) and not reach the outlet duct (45); in the second, more restrictive position, overdosing of smaller grains that could fall into the outlet duct (45) when expelled from the seed train by the leveling assembly (36) is better prevented.

[00106] For those crops with larger grains, the regulating flap (49) is positioned in the first position, as illustrated in Figure 4A. In this way, the flap (49) does not affect in any way the seed train circulating in the metering plate (32) and allows the grains to fall normally into the duct (45).

[00107] Alternatively, when the crop to be dosed has smaller grains, there is a risk that, after the leveling assembly (36) detaches the seeds located in each of the alveoli (321) of the plate (32), they will jump, causing more seeds than necessary to fall into the outlet duct (45). In this situation, the regulating flap (49) can be placed in a second position, as can be seen in Figure 4B. When the flap (49) is in this second position, the passage towards the outlet duct (45) is reduced, allowing the passage only of the circulating seeds located in the alveoli (321). Thus, the seeds that are expelled by the leveler and jump inside the chamber (40), collide against the flap (49), which also acts as a ramp so that they fall again towards the seed reservoir (48).

[00108] Preferably, to facilitate the configuration of said tab (49), it comprises a spring-loaded pull mechanism, whereby, when the tab (49) is pulled, the spring is compressed and Petition 870250085430, dated 09 / 22 / 2025, pp. 85 / 108 26 / 26 can be switched between the first and second positions, in grooves arranged for this purpose, in the seed chamber (40). When the tab (49) is released, the spring expands and fixes the position in the chosen groove, preventing it from moving unintentionally due to movements or vibrations of the machine. Petition 870250085430, dated 09 / 22 / 2025, pp. 86 / 108

Claims

1 / 6 CLAIMS 1. Pneumatic seed metering device (10) for precision seeders, characterized in that it comprises: a plastic housing (20) divided into a first half, fixed to the seeding train, which defines a seed chamber (40); and a second half, formed by a removable cover, which defines a vacuum chamber (30); wherein the seed chamber (40) comprises, on its outer part, a feed opening (41) through which the seeds to be metered enter the interior of said seed chamber (40); a regulating gate (42) for adjusting the grain level inside the seed chamber, wherein said regulating gate (42) is pivoting in relation to a connection point (421) and discretely adjustable, by means of an adjustment pin (422) which is placed in a series of grooves (423), arranged so that the adjustment can be made from the front and from the furthest end of the seeder body;a purge opening (43), to empty the chamber (40), which, in turn, comprises a gate (44) hinged in the discharge direction; an outlet duct (45) through which the grains exit for sequential distribution on the ground; an inspection cover (46), located at the top, which allows inspection of the seed train in the initial section of the route; an inspection hatch (47), located just above the outlet duct (45), which allows inspection of the seed distribution before it enters said duct (45); on one side, in its inner part, the seed chamber (40) comprises a seed reservoir (48), where the grains that enter through the feed opening (41) are accumulated;and a regulating flap (49), in L-shape, which can alternate between an open position, in which it does not exert any intervention on the seed train, and a closed position, in which it partially restricts the space available for the passage of the seed train towards the outlet duct Petition 870250085430, of 22 / 09 / 2025, page 87 / 108 2 / 6 (45); wherein the vacuum chamber (30) comprises, inside, a shaft (31) that transmits the rotation to a drive disc (311) in which a metering plate (32) is coupled with a series of alveoli (321), arranged parallel to its perimeter, to accommodate the seeds by the action of a vacuum pressure; an interchangeable support (33; 50; 60) containing a seal (34; 54; 64), which delimits a vacuum zone (302) within the vacuum chamber (30), where said seal (34; 54;64) comes into contact with the metering plate (32) to ensure the tightness of the vacuum zone (302), and also has a semicircular shape comprising a larger perimeter (342; 542; 642), which follows the contour of the vacuum chamber housing (30) and completely covers the line of alveoli (321) of the seed plate (32), interrupted by a radial section (341; 541; 641), which extends inwards, and a smaller perimeter (343; 543; 643), which closes the entire contour of the seal (34; 54; 64); and the said interchangeable support (33; 50; 60) further contains an ejector device (35; 55; 65), formed by an articulated arm (351; 551; 651), which contains at one of its ends a wheel (352; 552; 652) with a plurality of protrusions (353; 553; 653) that penetrate the alveoli (321) of the metering plate (32) to expel trapped solids; a floating leveling assembly (36), responsible for eliminating multiple seed occupations in the alveoli (321) of the plate (32).

2. Pneumatic dispenser (10), according to any of the preceding claims, characterized in that the inspection hatch (47) is transparent, so that the interior of the dispenser can be observed through the hatch (47) when closed.

3. Pneumatic doser (10), according to any of the preceding claims, characterized in that it further comprises, on its external part, a suction opening Petition 870250085430, of 22 / 09 / 2025, page 88 / 108 3 / 6 (37) for coupling to a vacuum source and generating, by means of an internal pneumatic circuit, the negative working pressure.

4. Pneumatic doser (10), according to claim 4, characterized in that it comprises, in the front part of the vacuum chamber (30), an inspection cover (39) that allows access to the interior of said internal pneumatic circuit.

5. Pneumatic doser (10), according to any of the preceding claims, characterized in that the shaft (31) has a slot (312) that allows the plate (32) to be fixed by means of a sliding lock (322), when positioned on said shaft (31) and supported against the drive disc (311), without the need for external fastening elements.

6. Pneumatic doser (10), according to any of the preceding claims, characterized in that the regulating flap (49) comprises a spring-loaded pull mechanism, whereby, to change the position, pulling the flap (49) compresses the spring and allows it to alternate between the first and second positions, in grooves provided for this purpose, in the seed chamber (40); and, when releasing the flap (49), the spring expands and fixes the position.

7. Pneumatic dispenser (10), according to any of the preceding claims, characterized in that the modular support (33; 50; 60) comprises a plurality of anchor points (331; 501; 601) for connection to the vacuum chamber body (30), wherein said anchor points (331; 501; 601) comprise screws, pressure pins, clips or clamps.

8. Pneumatic doser (10), according to any of the preceding claims, characterized in that the adjustment pin (422) of the regulating gate (42) comprises a spring-loaded pull mechanism which, when pulled, is released so that the pin (422) can move and change position and, when released, the pull engages in the selected groove (423), fixing the position.

9. Pneumatic doser (10), according to any of the preceding claims, characterized in that the hinged gate (44) covers the entire lower part of the seed chamber (40), so that, when opened, all the seeds contained in said chamber (40) fall by gravity towards the purge opening (43).

10. Pneumatic metering device (10), according to claim 9, characterized in that the purge opening (43) comprises a channeling ramp (431) that directs the purged seeds in a single direction, towards one of the sides of the seeding train.

11. Pneumatic doser (10), according to any of the preceding claims, characterized in that the seed chamber (40) comprises locking clamps (401) that lock against a linear spring (305) disposed in the vacuum chamber (30), securing the connection between both parts.

12. Pneumatic dispenser (10), according to any of the preceding claims, characterized in that the interchangeable support (33) comprises a seal (34), which is a flexible seal made of an elastomeric material.

13. Pneumatic dispenser (10), according to any one of claims 1 to 11, characterized in that the interchangeable support (50; 60) comprises a seal (54; 64), which is a rigid seal made of acetal resin or other polymer with a low coefficient of friction and high wear resistance.

14. Pneumatic dispenser (10), according to claim 13, characterized in that the rigid seal (54; 64) is composed of a first structural material in its body, such as metal, polymers, acetal resin, plastic or combinations thereof; and a second material, in the contact zone with the plate (32), such as acetal resin or other polymers with low coefficient of friction and high wear resistance. Petition 870250085430, dated 22 / 09 / 2025, page 90 / 108 5 / 6 15. Pneumatic doser (10), according to claim 13 or 14, characterized in that the seal (54) comprises actuating arms (544) that produce an orthoplanar spring effect, axially actuated, which, in turn, comprise fork-shaped levers (545) that deform orthogonally, abandoning the coplanar rest position when subjected to tension.

16. Pneumatic doser (10), according to claim 15, characterized in that the seal (54) comprises three actuating arms (544a; 544b and 544c), which, in turn, comprise different lever lengths (545), calibrated to adjust the compression as a function of their distance from the outer contour of the rigid seal (54).

17. Pneumatic doser (10), according to claim 13 or 14, characterized in that the interchangeable support (60) comprises an axially actuating orthoplanar spring (61), wherein said spring (61) has an outer contour (611) that imitates and follows the silhouette of the rigid seal (64); an inner perimeter (612), connected to the outer contour (611) by a plurality of radii (613); and a center (614), which comprises a central orifice (615), through which the shaft (31) passes; wherein, additionally, following said center (614), extends radially a plurality of actuating arms (617), which, in turn, comprise fork-shaped levers (618), which deform orthogonally, abandoning the coplanar rest position when subjected to stress.

18. Pneumatic doser (10), according to claim 17, characterized in that the orthoplanar spring (51) comprises three actuating arms (517A; 517B and 517C), which, in turn, comprise levers of different lengths (518), calibrated to adjust the compression as a function of their distance from the outer contour (511), connected to the rigid seal (54). Petition 870250085430, dated 22 / 09 / 2025, pp. 91 / 108 6 / 6 19. Pneumatic dispenser (10), according to any one of claims 13 to 18, characterized in that the interchangeable support (50; 60) further comprises an elastic membrane (53; 63) with a contour that imitates and follows the silhouette of the rigid seal (54; 64), wherein said flexible membrane (53; 63) seals the small gap that exists between the rigid seal (54; 64) and the support (50; 60), and is fixed by a rigid retaining plate (52; 62), which keeps it fixed. Petition 870250085430, dated 22 / 09 / 2025, pp. 92 / 108

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