Disc-shaped piece for seeding and seeding unit for pneumatic seeding machine and pneumatic seeding machine

Abstract

A seeding disc for a pneumatic seeder includes a disc member in which at least one loop of through-holes is formed. A seed side and an air side opposite to each other are defined in the disc member such that as a circumferential portion comprising at least one looped hole enters the bowl with respect to loose seed, the seeding disc is introduced into the bowl, the seed side and the air side are separated from each other due to a pneumatic pressure difference between the seed side and the air side. The seed is held by each of the at least one loop of holes at the seed side. The disc-like member includes at least one seed holding bracket portion adjacent to at least one of the looped holes at the seed side on the radially innermost side with respect to the respective looped hole. The seed holding bracket portion is provided at least angularly corresponding to some of the looped holes and extends in the circumferential direction such that when the disc is introduced into the bowl with respect to the loose seed, the weight of the loose seed located on the seed held by the holes of the looped holes is at least partially offset.

Description

Technical Field

[0001] The present invention relates to a sowing disk for a precision pneumatic seeder. Background Art

[0002] In the sowing units of precision agricultural sowing machines, it is known to use a disc provided with one or more circles of concentric holes for pneumatically attracting one seed per hole and conveying the attracted seeds to a duct for seed delivery, where the seeds are released. The term "hole" hereinafter is intended to mean a through opening of any shape capable of pneumatically attracting and holding the seeds to be distributed on one side of the disc. The definition of hole thus extends to non-cylindrical shapes and geometric shapes suitable for performing the described function.

[0003] Typical seed drills of this type are described, for example, in US Pat. No. 9,338,939 B1, US Pat. No. 6,176,393 B1, US Pat. No. 6,932,236 B2, US Pat. No. 7,448,334 B2 or EP Pat. No. 3,888,434 A2.

[0004] US6176393B1 describes in particular a sowing disc suitable for scattering fine seeds, which has a screen or grill mounted in the area of ​​the circled holes, against which the seeds are pneumatically attracted. In one of the examples described, the grill is removably retained by means of a seal which, together with the circumferential edge of the grill, is received in a corresponding circumferential cavity. The cavity has this single function and is therefore limited to the minimum radial dimensions necessary to retain the grill, which cavity is moreover always occupied during use by the edge of the grill and the corresponding seal.

[0005] US7448334B2 describes a flat disc-like circular seed disc provided with a series of circumferentially arranged seed attraction orifices. These orifices are spaced along a circumferential edge that is offset axially relative to the rest of the disc to approximate the seed release location and features of a cellular seed disc. This offset requires that the portion of the disc containing the openings be raised relative to the base mounting plane of the disc, the sole purpose of which is to allow the seed to fall into the correct position of the seed conduit.

[0006] EP3888434A2 describes a seed metering disc in which a seed agitator, such as a stirrer bag, may be located on the seed side of the disc. The only function of the stirrer bag is to stir the seeds in the seed pool.

[0007] The sowing disc of known configuration presents a number of problems in the phase of picking up the seeds and the associated transport towards the seed delivery duct. In fact, during the phase of picking up the seeds, when the looped hole section travels immersed in the loose seeds present in the seed pick-up chamber, the weight of the seeds overlapping the seeds held above the holes (retained seeds) bears on the retained seeds, which can affect the retention of the retained seeds. This factor limits the rotation speed of the disc, thereby allowing sufficient separation accuracy. In addition to this limited speed, the sowing accuracy is also affected.

[0008] Furthermore, when one or more seeds fall out of the corresponding holes of the disc, a pressure drop for holding the seeds is generated due to the greater airflow allowed by the free holes of the disc. This causes the seeds to fall out further from the holes of the disc and increases the propagation of the fault that the seeds are deposited on the ground. At most, a so-called stagnation state is reached, in which all seeds fall out of the disc due to the influence of the insufficient pressure difference established between the seed side and the air side of the disc.

[0009] It must be taken into account that modern seed drills use a large number of seeding units and that each unit is subjected during use to shocks, impacts, vibrations and similar damaging phenomena which certainly have the disadvantage of retaining the seed on the holes of the seeding disc. It is therefore necessary to strengthen the pneumatic system of these seed drills to take into account the above-mentioned damaging phenomena and problems. This involves increased construction costs of the machine, a lower overall energy efficiency level and a risk of malfunctions in any case. Summary of the invention

[0010] The technical problem addressed by the present invention is to provide a sowing disc which is structurally and functionally configured to overcome at least some of the disadvantages explained with reference to the cited prior art.

[0011] In view of this problem, the object of the present invention is to provide a sowing disc capable of providing better retention of the seeds to be transported, reducing the weight of the seeds surrounding the retained seeds and significantly limiting the possibility of stalling.

[0012] Another object is to provide a sowing disc which allows a greater rotation speed without affecting the sowing accuracy.

[0013] This problem is solved and these objects are at least partially achieved by a sowing disc configured according to one or more of the features of the invention.

[0014] According to a first aspect of the present invention, a disc for sowing for an air seeder comprises a disc member having at least one circle of through holes formed therein. Preferably, a seed side and an air side opposite to each other are defined in the disc member, so that as the circumferential portion including one or more circles of holes enters the bowl for loose seeds, when the disc is introduced into the bowl for loose seeds, the seeds are retained by each of the one or more circles of holes at the seed side due to the effect of the air pressure difference between the seed side and the air side.

[0015] Preferably, the disc-shaped member comprises at least one seed-holding bracket portion adjacent to the one or more circles of holes at the seed side, preferably adjacent to the one or more circles of holes at the seed side radially inwardly relative to the corresponding circles of holes. Preferably, the bracket portion is arranged at least angularly corresponding to some of the holes and preferably extends circumferentially so that: when the disc-shaped member is introduced into the bowl for loose seeds, the bracket portion at least partially acts counter to the weight of the loose seeds located on the seeds held by the circles of holes.

[0016] In this way, the seed engaged with the disk in the area of ​​the corresponding hole is not loaded and the interaction with the loose seed located above the seed in the bowl for loose seed is limited, thereby achieving a more effective retention of the seed on the corresponding hole until the retained seed is discharged from the bowl for loose seed.

[0017] Preferably, the bracket portion is separate from the apertures in the circle of apertures.

[0018] Preferably, for each hole of the disc, there is a bracket portion corresponding in angle to the corresponding hole, or for each pair of holes, there is a bracket portion corresponding in angle to the corresponding pair of holes. This arrangement improves the above effect.

[0019] In an important aspect of the invention, the bracket portion is located at the base of a recess or indentation recessed into the surface of the disc. This avoids protrusions upwards from the normal surface of the disc.

[0020] Preferably, the recess or concave indentation is non-through, that is, the recess or concave indentation is not a through hole. Preferably, the recess or concave indentation extends circumferentially to at least partially form an annular cavity, and even more preferably, the annular cavity is continuous.

[0021] In some embodiments, the radial dimension of the annular cavity is not less than the radial dimension of the hole. Preferably, the maximum radial dimension of the annular cavity is not less than the radial dimension of each hole in the circled hole. In other words, the annular cavity has a size similar to the size of the seed. This is coordinated with the mitigation mentioned above. It should be noted that, in this context, the term "radial dimension of each hole" preferably means the size measured along the radial direction of the disc-shaped member of each hole (that is, for example, the diameter of each hole).

[0022] Preferably, the radial dimension of the annular cavity and the radial dimension of the hole are of the same order of magnitude, i.e. the ratio between the radial dimension of the annular cavity and the radial dimension of the hole is between 0.1 and 10. Even more preferably, the ratio between the radial dimension of the annular cavity and the radial dimension of the hole is between 0.5 and 5. These features optimize the effect of the seed retaining bracket portion while maintaining the structural rigidity of the disc.

[0023] Preferably, the annular cavity is separate from the apertures in the circle of apertures.

[0024] The annular cavity is preferably a single cavity. More preferably, on the disc, the annular cavity is radially closer to the inside than the circle of holes, but adjacent to the circle of holes.

[0025] In one embodiment of the invention, there are stirring means for the seeds associated with the annular cavity, which preferably comprise a plurality of recesses extending in the disc-shaped member to a thickness corresponding to the thickness of the annular cavity and preferably directed radially towards the central part of the disc-shaped member. These radial recesses contribute to stirring the seeds in the seed pickup chamber.

[0026] In a preferred embodiment, the annular cavity has a depth, in particular an axial depth, which is between 5% and 90% relative to the thickness of the disk-shaped member.

[0027] The invention also relates to a sowing unit for a pneumatic seeder, comprising a disc having one or more of the aforementioned features, and to a pneumatic seeder comprising a carrier structure and a plurality of such sowing units engaged with the carrier structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The characteristics and advantages of the present invention will be better understood from the following detailed description of a preferred but non-limiting embodiment of the invention shown by way of non-limiting example, with reference to the accompanying drawings, in which:

[0029] - Figure 1 is a front view of a sowing disc constructed according to the present invention;

[0030] - Figure 2 yes Figure 1A radial cross-sectional view of a detail of a disk-shaped member along section line II-II;

[0031] - Figure 3 yes Figure 1 A sectional view of a detail of the disk-shaped member along the section line III-III;

[0032] - Figure 4 is a schematic diagram of a sowing unit of a precision pneumatic seeder according to the present invention;

[0033] - Figure 5 is a schematic diagram of a precision pneumatic seeder according to the present invention;

[0034] - Figures 6a to 6f is a schematic diagram of a detail of a sowing disc according to an embodiment of the present invention;

[0035] - Figure 7 is a partial perspective view of a sowing disc according to the present invention, the sowing disc being in a state depicted with seeds present on its surface;

[0036] - Figure 8 is a perspective view of a detail of a sowing disc according to another embodiment of the present invention. DETAILED DESCRIPTION

[0037] In the figures, a sowing disc constructed according to the invention is generally indicated by 1. The disc 1 is arranged in a housing 20 of a sowing unit 2. The pneumatic sowing machine 200 according to the invention may comprise a plurality of sowing units 2 engaged with a carrier structure 21 .

[0038] Preferably, the sowing disc 1 defines and separates two zones in a manner known per se inside the housing 20 of the sowing unit, between which a pressure difference is established. Preferably, a first zone 3 is facing the seed side 4 of the disc, in which a certain amount of seeds to be distributed is accommodated. The first zone 3 can constitute a seed pickup chamber, as better explained below. Preferably, the second zone 5 faces the air side 6 of the disc 1, and advantageously a pneumatic pressure is established in the second zone 5 that is lower than the pressure in the first zone 3.

[0039] Preferably, a circle of holes 7 (but more than one circle of holes, if applicable) allows the passage of air between the first zone 3 and the second zone 5, the circle being concentric with the axis of rotation X of the disc 1 and passing through the disc-like member of the disc itself. The disc is introduced into the seeds contained in the pickup chamber of the first zone 3 by rotating about the axis X, and the seeds remain bound to each hole, in particular on the seed side, due to the influence of the pressure difference between the first zone and the second zone, so that the seeds are transported by the disc towards the delivery pipe 8, wherein vacuum breaking means 9 (for example, by means of blocks or rollers) close the corresponding holes, thereby generating an interruption of the pressure difference and thus causing the seeds to fall into the pipe 8.

[0040] In some embodiments, the hole 7 of the ring includes a truncated cone-shaped annular portion 12 starting from the seed side 4 towards the air side 6, which protrudes towards the axis of the hole 7 and preferably ends in a lip 13, followed by a widened portion 31 of the hole, which preferably extends to the air side 6 of the disc.

[0041] An annular cavity 14 is preferably formed behind the circle of holes 7. The annular cavity 14 is preferably concentric with respect to the circle of holes 7 and is preferably closed in a continuous circle. In some embodiments, the annular cavity 14 is formed at least at the seed side of the disk at the radially innermost side relative to the circle of holes. The annular cavity 14 is preferably a single cavity ( Figures 1 to 3 , Figure 6d , Figure 6e ), however, it can also be provided that there are a plurality of concentric grooves located radially inside or outside the ring-forming holes ( Figure 6b , Figure 6c ).

[0042] The function of the annular cavity 14 is to lighten the weight of the seeds present in the pick-up chamber (area 3) next to the seeds (loose seeds) to be retained on the corresponding holes 7, such as Figure 7 As shown in the example of . The weight saving effect mainly stems from the fact that the edge 16 of the annular cavity close to the circle of holes 7 defines (and performs the seed containment function) a seed holding bracket portion 17, which is recessed along the thickness of the disc-shaped member by a thickness, which is preferably between 5% and 90% of the thickness of the disc-shaped member. Alternatively, the bracket portion can protrude from the disc-shaped member by an axial protrusion relative to the disc-shaped member. Whether in the protruding solution or in the recessed solution, the bracket portion 17 is preferably arranged at least angularly corresponding to some of the holes 7, and the bracket portion 17 extends in the circumferential direction in such a way that when the disc-shaped member is introduced into the seed pickup chamber (a collecting bowl for including loose seeds), the bracket portion 17 at least partially offsets the weight of the loose seeds located on the seeds held by the circle of holes.

[0043] Preferably, for each hole 7 of the disc, a seed holding bracket portion 17 is configured, which corresponds to the corresponding hole 7 in terms of angle ( Figure 6a ), or for each pair of holes, a bracket portion ( Figure 6f ), or even a continuous carrier portion in the form of an annular ring ( Figures 1 to 3 , Figure 6b to Figure 6e ).

[0044] In the proposed embodiment, the bracket portion 17 is located at the base of a recess 18, which can extend in the circumferential direction to at least partially form an annular cavity or to form a continuous annular cavity, such as Figures 1 to 3 As described in the preferred example.

[0045] It is provided that, in some embodiments, the circumferential extension of the cross section of the partially formed annular cavity may be, for example, at least 1.5 times the diameter of the hole 14 , and in some examples at least 3 times the diameter of the hole 14 .

[0046] Experimental tests have shown that, for holes 7 of the same geometry, the presence of the annular cavity 14 significantly increases the probability of effective seed pick-up, forming a secure hold of the seeds despite collisions with other seeds in the pick-up chamber, thus allowing a greater rotation speed of the disc for the same separation accuracy. The presence of the annular cavity 14 and the stabilizing effect on the seeds held by the disc further avoid the stall effect that is generated on the disc when one or more seeds are detached from the corresponding hole 7 or are not combined with the corresponding hole 7, causing air to pass freely through the disc and thus reducing the aerodynamic holding force on the seeds located in the remaining holes 7 on the disc. The effect of reduced holding capacity propagates, the holding capacity gradually becomes worse as the seeds detach from the disc, thus causing in particular the propagation of stall effects and sowing accuracy failures.

[0047] Preferably, the disc-shaped member is also provided with stirring means for the seeds, which in the proposed example can advantageously be formed by a plurality of recesses 15, which are arranged alternately with respect to the overall thickness of the disc-shaped element, and which extend from the annular cavity 14 in a radial direction towards the central part of the disc-shaped element. Preferably, projections 19 for stirring the seeds are defined between circumferentially adjacent radial recesses 15. In this way, the projections 19 do not have a negative impact on the gripping of the seeds in the region of the corresponding holes.

[0048] refer to Figure 8In the example of , it can also be provided that projections 19 for stirring the seeds can be formed in the annular cavity 14. Preferably, the axial thickness of these projections 19 is less than the entire thickness of the disc. In this way, the presence of the projections 19 does not interrupt the continuity of the annular cavity 14, at least in the part of the annular cavity that is axially located between the top of the projections 19 and the conventional surface of the disc.

[0049] In some embodiments, Figure 2 As shown in the example of , the radial dimension L1 of the annular cavity is not less than the radial dimension L2 (eg, inner diameter) of the hole, or alternatively, the radial dimension L1 of the annular cavity is not less than 0.5 times the radial dimension L2 of the hole.

[0050] In some embodiments, the ratio between the radial dimension L1 of the annular cavity and the radial dimension L2 of the hole is less than or equal to 5, and in some specific examples, the ratio between the radial dimension L1 of the annular cavity and the radial dimension L2 of the hole may be less than or equal to 2.

[0051] In some embodiments, the annular cavity 14 has a depth t, in particular an axial depth, preferably between 5% and 50% of the radial dimension of the annular cavity itself, and more particularly between 10% and 25% relative to the aforementioned radial dimension.

[0052] The invention thus solves the problem posed, achieving a number of advantages, especially when used on pneumatic seed drills of larger dimensions, in which the number of seeding units is large and the problems associated with the pneumatic seal between the seed and the disk are therefore multiplied. In particular, an improved adhesion of the seed is obtained, thereby increasing the sowing accuracy, making it possible to increase the sowing speed without disadvantages, reducing the stalling effect of the seed, and reducing the energy consumption of the entire seed drill.

Claims

1. A sowing disc (1) for a pneumatic seeder, the sowing disc (1) comprising a disc-shaped member (100), wherein the disc-shaped member (100) is formed with at least one circle of through holes (7), wherein the disc-shaped member is defined with a seed side (4) and an air side (6) opposite to each other, so that as the circumferential portion including at least one circle of holes (7) enters a bowl-shaped member for loose seeds, when the sowing disc is introduced into the bowl-shaped member for loose seeds, due to the effect of the pneumatic pressure difference between the seed side (4) and the air side (6), the seeds are retained by each hole in the at least one circle of holes at the seed side (4), characterized in that The disc-shaped member includes at least one seed holding bracket portion (17), which is adjacent to at least one circle of the circled holes on the seed side at the radial innermost side relative to the corresponding circled holes, and the seed holding bracket portion is at least arranged to correspond to some of the holes in the circle at an angle, and the seed holding bracket portion extends circumferentially so that: when the disc-shaped member is introduced into the bowl-shaped member regarding the loose seeds, the seed holding bracket portion at least partially offsets the weight of the loose seeds located on the seeds held by the circled holes.

2. The sowing disc (1) according to claim 1, wherein: The sowing disc (1) comprises a seed holding bracket portion (17) for each hole or each pair of holes in the circle of holes (7), and the seed holding bracket portion (17) corresponds to the corresponding hole or the corresponding pair of holes in angle.

3. The sowing disc (1) according to claim 1 or 2, wherein: The seed holding bracket (17) is located at the base of the recess (18).

4. The sowing disc (1) according to claim 3, wherein: The recess extends in the circumferential direction to at least partially form an annular cavity (14).

5. The sowing disc (1) according to claim 4, wherein: The annular cavity (14) is continuous.

6. The seeding disc according to claim 4 or 5, wherein: The radial dimension (L1) of the annular cavity (14) is not less than the radial dimension (L2) of each hole in the looped holes (7).

7. The sowing disc according to any one of claims 4 to 6, wherein: The sowing disc comprises a plurality of radial recesses (15) which are open in the annular cavity (14) at the radially innermost position relative to the annular cavity, and protrusions (19) for stirring seeds are defined between circumferentially adjacent radial recesses (15).

8. The sowing disc according to any one of claims 4 to 7, wherein: The radial dimension (L1) of the annular cavity (14) and the radial dimension (L2) of the hole (7) are of the same order of magnitude.

9. The sowing disc according to any one of claims 4 to 8, wherein: The ratio between the radial dimension (L1) of the annular cavity (14) and the radial dimension (L2) of the hole (7) is between 0.5 and 5.

10. A sowing unit (2) for a pneumatic sowing machine, wherein: The sowing unit (2) comprises a sowing disc according to any one of the preceding claims.

11. Planting unit according to the preceding claim, wherein The sowing unit comprises a housing (20), the sowing disc being arranged inside the housing (20) to define and separate a first area (3) and a second area (5), a pneumatic pressure difference being established between the first area (3) and the second area (5), wherein the first area (3) faces the seed side (4) of the sowing disc and delimits a bowl for loose seeds, and wherein the second area (5) faces the air side (6) of the sowing disc.

12. A pneumatic seed drill (200), wherein: The pneumatic seed drill (200) comprises a carrier structure (21) and a plurality of seeding units according to claim 10 or 11, the seeding units being arranged on the carrier structure.

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