DESCRIPTION

Technical field

The invention relates to a seeds distribution device for precision sowing machines and a precision sowing machine comprising such a device of the type comprising the features set out in the preamble of the respective independent claims.

Technological background

The precision of sowing is a crucial prerequisite in the field of agriculture because the yield of product at harvest depends substantially on the density of the plants per unit of surface-area sowed. In particular, the density of sowing in turn depends on the careful compliance with the sowing spacing. In fact, this measure is a function both of the construction precision characteristics of the sowing machine and of the speed of sowing. Naturally, in order to allow a good productivity of the harvest, it is necessary for the speed of the sowing to be maximized so as to allow the operator to sow great surface-areas quickly.

The best results in maximizing the speed and precision of sowing are obtained with pneumatic sowing machines which typically convey the seed to the ground by means of pneumatic apparatuses which produce a positive or negative pressure inside a chamber in order to engage the seeds individually with the holes of a sowing disc.

A typical problem relating to the use of these seed selectors with perforated discs is the elimination of duplicates of seeds or failures which can compromise the sowing regularity. In order to prevent failures, it is necessary to make the processing of the seeds on the sowing disc quite effective but this is at the expense of the presence of duplicates of seeds which are both processed by a single hole.

To this end, there are used in association with the sowing discs devices for separating the seed which remove duplicate seeds which are processed by the same hole. US2016/0255768 describes a sowing unit which has a double-abutment separator which collaborates with a distributor disc so as to reduce the tolerance between the disc and the double abutment and thereby to reduce the excessive seeds.

However, this product is not suitable for providing a system for eliminating duplicates of seeds received in the distributor disc which acts in an effective manner with different types of seeds.

In fact, the double-abutment separation is configured to be able to operate in an effective manner only for a specific type of seeds having specific dimensions (greater or smaller), configurations (elongate, elliptical, rounded, etc.) and/or other characteristics (higher or lower density, etc.) which require specific positions of the abutments with respect to the trajectory followed by seeds conveyed in the holes of the distributor disc.

Therefore, it is evident that by changing the type of seed it becomes necessary to replace the elimination members, thereby losing a substantial quantity of time during these operations.

Summary of the invention

An object of the present invention is to provide a seeds distribution device and a precision sowing machine comprising such a device which overcome at least one of the disadvantages of the prior art identified.

Within this object, an objective of the invention is to produce a seed distribution device which eliminates the duplicates of seeds which are accidentally positioned on a seed selector disc in an effective manner and which is simply adjustable in order to be adapted to different types and forms of seeds.

According to an embodiment of the present invention, a seed distribution device for precision sowing machines comprises a housing for a seed selector disc which is mounted for rotation about a central rotation axis, at least one ring of holes in the seed selector disc which is provided to transport seeds over a circular trajectory.

Preferably, the seed distribution device for precision sowing machines comprises a first singulator comprising first engagement elements which collaborate with engagement means of the housing so as to allow adjustment of the position of the first singulator with respect to the circular trajectory of the seeds.

In this manner, there is defined a disruptive selection path for a seed of the transported seeds which is preferably located between the first singulator and the circular trajectory of the seed in which a profile of the first singulator interferes with the circular trajectory overcoming any duplicates of seeds and further centring the desired seed in the transport hole or cell of the seed selector disc. Therefore, it is possible by means of the first engagement elements to move the first singulator with respect to the circular trajectory so as to be able to modify the disruptive selection path of the seed in accordance with the specific characteristics of the seed being used.

Advantageously, the first singulator comprises first engagement elements which interact with engagement means of the housing so as to allow adjustment of the position of the first singulator with respect to the circular trajectory of the seeds. Preferably, the first engagement elements are a through-hole and a through-slot.

According to an embodiment, the first singulator comprises a through-hole and a through-slot, wherein the through-hole is engaged with permitted rotation on a first pin, the first pin being fixedly secured to an eccentric element which is secured with permitted rotation to the housing, the through-slot being engaged on a second pin of the housing and the through-slot being formed so as to allow a rotational-translational movement of the first singulator with respect to the central trajectory.

In this context, the term "rotational-translational" is intended to refer to a complex movement of the first singulator which is composed, at least over a portion thereof, of a rotational movement and a translational movement. Advantageously, the translational movement is obtained by means of a sum of translation movements parallel with radial and tangential components of the seed selector disc.

It is thereby possible to move the first singulator towards or away from the central trajectory in a translational manner, affording the advantage of maintaining an orientation of the first singulator which is more parallel with the central trajectory at the various distances from the central trajectory itself with respect to movements which are only rotational about a rotation axis which move away from the central trajectory to a greater extent the portions of the first singulator which are further away from the above- mentioned rotation axis.

Preferably, by varying the orientation of the through-slot with respect to the radius of the seed selector disc passing through the second pin, it is possible to define the inclination at which the first singulator interacts with the region near the central trajectory, thereby defining the intensity and the distribution of the impact forces transferred to the seed, or to the duplicate seeds if present, when transported along the circular trajectory.

In this context, there are defined as "aggressive" conditions the conditions of interaction between a singulator and the central trajectory which tend to develop impact forces greater than other interaction forces which are produced between the transported seed (by means of the seed selector disc) and portions of the above-mentioned singulator.

According to an embodiment, the novel aspect carried out according to the present invention is a seed distribution device for precision sowing machines comprising a housing for a seed selector disc which is mounted for rotation about a central rotation axis, at least one ring of holes in the seed selector disc which is provided to transport seeds over a circular trajectory, a first singulator and a second singulator which are mounted so as to be radially facing on a housing at opposite sides of the circular trajectory of the seeds and being distal and proximal with respect to the central rotation axis.

Advantageously, the first singulator and second singulator are preferably configured so as to both act on at least a portion of the circular trajectory of the seeds, defining a disruptive selection path for the seed.

It may be noted that the characteristics described above for the first singulator in relation to the technical solution of using a single singulator can be replicated and used for the first singulator and/or the second singulator which is/are used in the other embodiments relating to the present invention.

Preferably, the first singulator and/or the second singulator can be independently adjusted selectively to modify at least locally the disruptive path so as to eliminate duplicates of seeds from the disc without creating failures.

It is thereby possible to selectively move the two separators independently, thereby creating disruptive selection paths which involve a seed which is transported along the circular trajectory and which are specifically imposed for the type of seed desired.

As a result of these solutions, the first selector and the second selector move towards each other in relative terms, interacting at a distal and proximal side with a seed which passes along the circular trajectory, respectively, allowing there to be a single seed for each hole of the ring of holes, advantageously eliminating duplicates and possible failures.

Further advantageously, it is possible by means of this technical solution to define the disruptive selection path for the seed as the space between the first and the second singulator, through which the seeds retained on the seed selector disc pass, producing a selection at opposite sides with respect to the central trajectory.

Advantageously, the first singulator comprises a through-hole and a through-slot, the through-hole being engaged for rotation on the second pin, the through-slot being engaged for rotation on the first pin which is fixedly secured to an eccentric element which is rotatably secured to the housing and the through-slot being formed so as to allow the first singulator a movement along a circumferential arc which is centred in the through-hole by means of rotation of the eccentric element.

In so doing, it is possible to adjust by simple rotation the first singulator by modifying the distance between the first singulator and the second singulator and thereby modifying the spatial development of the disruptive selection path by further increasing the movement of an end of the first singulator which is placed further away from the rotation axis passing through the above-mentioned through-hole, thereby making the selection more effective, for example, for seeds which are attached to the seed selector disc in a manner which is initially weaker.

According to an embodiment, the first singulator comprises a through-hole and a through-slot. Furthermore, the through-hole is engaged rotatably on the first pin, the first pin being fixedly secured to an eccentric element which is rotatably secured to the housing, the through-slot being engaged on the second pin and the through-slot being formed so as to allow the first singulator rotational-translational movement with respect to the second singulator during rotation of the eccentric element.

It is thereby possible to move the first singulator towards or away from the central trajectory and the second singulator in an at least partially translational manner, affording the advantage of maintaining an orientation of the first singulator which is more parallel with the central trajectory at the various distances from the central trajectory and the second singulator. According to another embodiment, the first singulator is secured in a rigid manner with respect to the housing and only the second singulator is made removable with respect to the housing.

Preferably, the through-slot has a rectangular form with the vertices being rounded and a spacing L between the two long sides and the pin on which the through-slot engages has a substantially cylindrical form having a diameter small than the spacing between the two long sides.

In this manner, the slot can rotate and/or move in translation on the above- mentioned cylindrical pin, thereby creating complex movements, including rotational-translational movements, of the separator involved.

According to an embodiment, the through-slot comprises a main longitudinal axis which is inclined by an angle between 90° and 115° with respect to the extension of the radius of the seed selector disc passing through the location of the through-slot which is most proximal to the central rotation axis. Advantageously, this angle is 100°.

In this manner, it is possible to determine how aggressive the separator comprising the through-slot is with regard to the central trajectory of the seed, determining in each case the force with which to allow the separator to strike the seed which is retained on the seed selector disc.

Preferably, the first singulator and the second singulator are substantially plate-like and co-planar relative to each other.

This minimizes hindrances, optimizing the efficiency of the separator(s) and thereby increasing the operating precision of the seed distribution device. According to an embodiment, the first singulator comprises a first plurality of teeth which project towards the central rotation axis from a first central portion which is circumferentially arcuate. This technical solution allows the definition of a disruptive selection path with a complex development, being defined by portions which are locally more proximal with respect to the central trajectory (and therefore more aggressive with respect to the seed transported) and portions which are locally further away from the central trajectory (and therefore less aggressive with respect to the seed transported).

Furthermore, the circumferentially arcuate form with respect to the seed selector disc of the central portion allows the above-mentioned disruptive selection path to be followed and modified in an optimum manner with respect to the central trajectory.

Preferably, the first plurality of teeth comprise at least one tooth having a substantially saw-tooth-like form .

It is possible by means of this technical solution to determine in a fine manner how aggressive the tooth has to be with respect to the seed which is passing through and a surrounding region thereof which extends freely. This further allows a definition of the impact force on the seed transported and any duplicate seeds which are present, thereby making the elimination thereof easier.

According to an embodiment, each tooth of the first plurality of teeth has a profile which gradually becomes more proximal with respect to the circular trajectory travelled by the seed as a function of the direction of rotation of the seed selector disc.

In this manner, it is possible to determine a sequential nature of separator portions which are gradually more aggressive with respect to the seed transported. In fact, it is advantageous to emphasize that the seed tends to be secured with less force at the start of the removal action and abuts the surface of the seed selector disc and that this retention force, at least for a predetermined sector, gradually increases as the seed moves along the circular trajectory in accordance with the direction of rotation of the seed selector disc.

It thereby appears to be advantageous, for example, to provide for teeth having increasingly great aggressiveness as a function of the position of the seed over the trajectory so as to optimize the relationship between the impact force acting and the retention force operating on the seed, further improving the efficiency of the seed distribution device.

Preferably, the first plurality of teeth comprise three teeth which are spaced apart from each other by a first pitch and which are spaced apart by two recesses of the first singulator.

In this manner, there is produced a type of disruptive selection path which is partially sinusoidal between the first singulator and the central trajectory and/or the second singulator which better allows the periodic alternation between zones which are aggressive to a greater or smaller extent and therefore a better selection of the single seed desired at the same time as a better centring of the seed with respect to the corresponding hole of the seed selector disc.

It is important to note that better centring of the seed on the cell of the seed selector disc allows a more centred final release of the seed into the ground and therefore a more precise and efficient sowing operation.

According to an embodiment, the second singulator comprises at least a second tooth, preferably at least two teeth, which project(s) from a second main arcuate portion of the second singulator and which faces the first singulator.

In this case, therefore, it also becomes possible to define an additional disruptive selection path with a complex development, being defined by portions of the second singulator which are locally more proximal with respect to the central trajectory (and therefore more aggressive with respect to the seed transported) and portions which are locally further away from the central trajectory (and therefore less aggressive with respect to the seed transported).

Preferably, the second plurality of teeth comprise two teeth.

According to an embodiment, the three teeth of the first plurality of teeth and the two teeth of the second plurality of teeth are arranged in a co- planar and alternating manner relative to each other so that each of the two teeth of the second plurality of teeth faces one of the two recesses of the first singulator, thereby defining an adjustable disruptive selection path which has a sinusoidal development between the first plurality of teeth and the second plurality of teeth.

In this manner, it is possible to define an optimum sinusoidal disruptive path which allows local application of more and less aggressive zones to the seed which is retained in a periodically alternating manner both by the first singulator and by the second singulator, maintaining a total section of the disruptive selection path which is substantially constant as a function of the circular trajectory. In the embodiments previously described, the first singulator is removable while the second singulator is fixed. This technical solution may be considered simply by way of a non-limiting example and the present invention actually includes the embodiments in which the first singulator is fixed and the second singulator is removable or both the separators are independently removable.

The present invention relates to a precision sowing machine comprising a seeds distribution device which is constructed according to the characteristics described above.

Description of the drawings

The features and advantages of the invention will be better appreciated from the detailed description of an embodiment thereof which is illustrated by way of non-limiting example with reference to the appended drawings, in which :

- Figure 1 is a front view of a seeds distribution device constructed according to the present invention,

- Figure 2 is a front view, to an enlarged scale, of separators of the seeds distribution device of Figure 1,

- Figure 3 is a front view, to an enlarged scale, of another embodiment of separators of the seeds distribution device of Figure 1,

- Figures 4a, 4b, 4c are front views of different configurations of use of the device of Figure 1,

- Figures 5a, 5b, 5c are front views of different configurations of use of the device of Figure 1 when the separators of Figure 3 are installed.

Detailed description of an embodiment

In the Figures, there is designated 1, 100 a seed distribution device for a precision sowing device. Preferably, the seed distribution device 1, 100 for a precision sowing device comprises a housing 60 for a seed selector disc which is mounted for rotation about a central rotation axis Z, at least one ring of holes on the seed selector disc provided to transport seeds S, over a circular trajectory C, a first singulator 10, 110 and a second singulator 20, 120 which are mounted radially facing a housing 60 at opposite sides of the circular trajectory C of the seeds S and which are distal and proximal with respect to the central rotation axis Z, respectively.

Figure 2 shows an example of a circular trajectory C illustrated with broken lines.

Advantageously, the first singulator 10, 110 and the second singulator 20, 120 are configured, that is to say, arranged, so as to both act on at least a portion of the circular trajectory C of the seeds S, defining a disruptive selection path for the seed.

The first singulator 10, 110 and the second singulator 20, 120 define a disruptive selection path for the seeds S so that the first singulator 10, 110 and/or the second singulator 20, 120 is/are independently adjustable selectively in order to modify at least locally the disruptive path so as to eliminate duplicates of seeds by the seed selector disc without creating failures.

The above-mentioned seed selector disc is capable of conveying and transporting the seed set down in the above-mentioned cell along the circular trajectory C.

By way of non-limiting example, the circular trajectory C illustrated in Figure 2 has a laying radius of the holes of the seed selector disc equal to 95 mm and is equivalent (even if not indicated) in all the Figures of the present invention.

According to an embodiment, the first singulator 10, 110 and the second singulator 20, 120 comprise first and second engagement elements 9a, 9b, respectively, which are arranged to interact with engagement means 9c of the housing 60 so as to allow the above-mentioned independent selective adjustment of the first singulator 10, 110 and/or second singulator 20, 120 in order to modify at least locally the disruptive selection path.

Preferably, the above-mentioned first and second engagement elements 9a, 9b are elements of the mechanical type (for example, holes, slots, etc.), magnetic type (permanent magnets, electromagnets, etc.) or the like, and the engagement means 9c are elements of the mechanical type (for example, pins, teeth, etc.), magnetic type (permanent magnets, electromagnets, etc.) or the like.

With reference to Figure 3, the first singulator 10 preferably comprises a through-hole 11 and a through-slot 12, the through-hole 11 being engaged rotatably on a second pin 12a, the through-slot 12 being engaged rotatably on a first pin 11a which is fixedly secured to an eccentric element l ib, this element being rotatably secured to the housing 60. Furthermore, the through-slot 12 is formed so as to allow the first singulator 10 to move along a centred circumferential arc in the through-hole 11 during rotation of the eccentric element l ib.

With reference to Figures 5a, 5b and 5c, there are shown three configurations in which the first singulator 10 and the central rotation axis Z are at a minimum, mean and maximum mutual distance, respectively. According to an embodiment, the first singulator 110 comprises a through- hole 111 and a through-slot 112 in which the through-hole 111 is engaged with permitted rotation on the first pin 111a, the first pin 111a being fixedly secured to an eccentric element 111b which is rotatably secured to the housing 60, the through-slot 112 being engaged with the second pin 112a and the through-slot 112 being formed so as to allow a rotational- translational movement of the first singulator 110 with respect to the second singulator 120 during rotation of the eccentric element 111b.

Advantageously, the first singulator 10, 110 and the second singulator 20, 120 are produced from materials having high levels of modulus of elasticity and hardness, such as, for example, steel, anodized aluminium, materials sintered so as to ensure good resistance to wear, etc. Furthermore, the above-mentioned through-hole and through-slot are preferably produced by means of moulding or casting or drilling or milling processing or similar industrial techniques.

According to an embodiment, the housing is produced from aluminium.

Preferably, with reference to Figures 2 and 3, the through-slot 12, 112 has a rectangular form with the vertices being rounded and a spacing L between the two long sides and the pin 11a, 112a on which the through-slot 12, 112 engages has a substantially cylindrical form having a diameter d small than the spacing L.

According to an embodiment shown in Figure 2, the through-slot 12, 112 comprises a main longitudinal axis I which is inclined by an angle a between 90° and 115° with respect to the extension of the radius of the seed selector disc passing through the location of the through-slot 12, 112 which is most proximal to the central rotation axis Z. Advantageously, this angle a is equal to 100°.

Preferably, the first singulator 10, 110 and the second singulator 20, 120 are substantially plate-like and co-planar relative to each other.

Advantageously, the first singulator 10, 110 and the second singulator 20, 120 have a thickness between 2 mm and 3 mm and a linear extent between 60 mm and 180 mm .

According to an embodiment, the first singulator 10, 110 comprises at least a first tooth 14, 114, preferably at least two teeth, which project(s) towards the central rotation axis Z from a first central portion 13, 113 which is circumferentially arcuate.

With reference to Figures 2 and 3, the first central portion 13, 113 is an annular or toroidal sector which extends circumferentially in accordance with a preferred radius of curvature. Advantageously, this radius of curvature is greater than or equal to the radius of curvature of the central trajectory C.

Preferably, the first plurality of teeth 14, 114 comprise at least one tooth 14a, 114a which has a substantially saw-tooth-like form.

Advantageously, the connection points between the first central portion 13, 113 and the saw tooth define inflection points between changes of concavity of the first central portion and a portion of the saw tooth which is distal from the first central portion itself.

In this manner, it is possible to have a profile of the tooth which engages with the seed S in a selectively gradual manner, increasing the possibility of removing the excess seeds and correctly centring the desired seed in the predetermined cell.

According to an embodiment, each tooth of the first plurality of teeth 14, 114 has a profile which is increasingly proximal with respect to the circular trajectory C travelled by the seed as a function of the direction of rotation of the seed selector disc.

Advantageously, the difference between the distances of the teeth which can be measured by the distal or local portion thereof with respect to the central rotation axis Z is more or less from 0 to 15% of the mean of the distances of the teeth themselves.

Preferably, the first plurality of teeth 14, 114 comprise three teeth 14a, 14b, 14c, 114a, 114b, 114c which are spaced apart from each other by a first pitch PI and which are spaced apart by two recesses 14d, 14e, 114d, 114e of the first singulator 10, 110. With reference to Figures 4a, 4b, 4c and 5a, 5b, 5c, it is clearly evident that the same portions of the above-mentioned first singulator 10 are located with minimum, mean and maximum spacings with respect to the central rotation axis Z as a function of the angles of rotation applied to the eccentric l ib, 111b.

In order to provide a more comprehensible description and with reference to Figures 4a, 4b, 4c, there are defined three distances from the central rotation axis Z of a first, second and third tooth Dl lOa, Dl lOb, Dl lOc, respectively. By way of non-limiting example, reference may be made below to a Table (Table 1) which indicates the above-mentioned values as a function of the configuration of the first singulator with minimum, mean and maximum spacings with respect to the central rotation axis Z. Distance Minimum Mean Maximum

configuration configuration configuration

Dl lOa 94.95 97.34 97.34

Dl lOb 94 98.93 100.75

Dl lOc 93.53 98.63 101.52

Table 1

Similarly, in order to provide a more comprehensible description and with reference to Figures 5a, 5b, 5c, there are defined three distances from the central rotation axis Z of a first, second and third tooth Dl la, Dl lb, Dl lc, respectively, in relation to another embodiment of the present invention. By way of non-limiting example, reference may be made below to a Table (Table 2) which indicates the above-mentioned values as a function of the configuration of the first singulator with minimum, mean and maximum spacings with respect to the central rotation axis Z.

Table 2

It can readily be seen (in particular in the configuration with maximum spacing) by comparing the data contained in Table 1 and in Table 2 how the embodiment of Figure 2 allows a spacing to be maintained with respect to the central rotation axis Z which is more uniform between the various teeth. According to an embodiment, the second singulator 20, 120 comprises a second plurality of teeth 24, 124 which project from a second main arcuate portion 23, 123 of the second singulator and which face the first singulator 10, 110.

With reference to Figures 2 and 3, the second central portion 23, 123 is an annular or toroidal sector which extends circumferentially in accordance with a preferred radius of curvature. Advantageously, this radius of curvature is small than or equal to the radius of curvature of the central trajectory C.

Preferably, the second plurality of teeth 24, 124 comprise at least one tooth 24a, 124a which has a substantially saw-tooth-like form .

Advantageously, the connection points between the second central portion 23, 123 and the saw tooth define inflection points between changes of concavity of the first central portion and a portion of the saw tooth which is distal from the first central portion itself.

In this manner, it is possible to have a profile of the tooth which engages with the seed S in a selectively gradual manner by increasing the possibility of removing the excess seeds and correctly centring the desired seed in the predetermined cell.

According to an embodiment, each tooth of the second plurality of teeth 24, 124 has a profile which becomes increasingly more proximal to the circular trajectory C which is travelled by the seed as a function of the direction of rotation of the seed selector disc. Advantageously, the difference between the distance of the teeth which are measurable by the distal or local portion thereof with respect to the central axis of rotation Z is between more or less 0 and 15% of the mean of the distances of the teeth.

Preferably, the second plurality of teeth 24, 124 comprise two teeth 24a, 24b, 124a, 124b.

Advantageously, the two teeth 24a, 24b, 124a, 124b of the second plurality of teeth 24, 124 are positioned at the distal ends of the second central portion 23, 123, respectively.

According to an embodiment and with reference to Figures 1, 2 and 3, the three teeth 14a, 14b, 14c, 114a, 114b, 114c of the first plurality of teeth 14, 114 and the two teeth 24a, 24b, 124a, 124b of the second plurality of teeth 24, 124 are arranged in a co-planar and alternating manner relative to each other so that each of the two teeth 24a, 24b, 124a, 124b of the second plurality of teeth 24, 124 faces one of the two recesses 14d, 14e, 14d, 14e of the first singulator 10, 110, thereby defining a disruptive selection path which can be adjusted with a sinusoidal development between the first plurality of teeth 14, 114 and the second plurality of teeth 14, 124.

In the embodiments described above, the first singulator can be moved while the second singulator is fixed. This technical solution may be considered simply by way of non-limiting example and in fact the present invention includes the embodiments in which the first singulator is fixed and the second singulator is removable or both the separators can be removed independently.

The present invention relates to a precision seeding device comprising a seeds distribution device 1, 100 which is constructed according to the characteristics described above.