Dosing unit for a seeding machine.

Abstract

A metering unit (24) for a seed drill, having a seed disc (38) which can be driven in rotation about its axis by a drive (88) and comprising a number of openings (50) distributed in its circumferential direction for receiving the seeds, in which the seed disc (38) is removably connectable or connected to a shaft (54) of the drive (88) by a mounting assembly (46), the mounting assembly (46) comprising a rear fixing surface (58) for the seed disc (38), a central section (56) and a separate locking element (62), equipped with cams (76), and which is rotatable relative to the central section (56), the seed disc (38) comprising a central opening complementary to the central section (56) and niches (74) extending from the central opening and complementary to the cams (76),such that the locking element (62) is movable between a first rotation position in which the cams (76) of the locking element (62) abut the seed disc (38) and clamp the seed disc (38) between the cams (76) and the rear fixing surface (58), and in a second rotation position, in which the cams (76) of the locking element (62) are aligned with the recesses (74) of the seed disc (38), in which the locking element (62) is lockable at the central section (56) by a fitted connection.

Description

Title of the invention: Dosing unit for a seeding machine. Subject of the invention

[0001] The present invention relates to a metering unit for a seeding machine, having a seed disc rotatable about its axis by a drive, and comprising a number of openings distributed in its circumferential direction for receiving seeds, wherein the seed disc is removably connectable, or connected with a shaft of the drive by a mounting assembly, the mounting assembly comprising a rear fixing surface for the seed disc, a central section and a separate locking element equipped with cams, which is rotatable relative to the central section and the seed disc comprises a central opening complementary to the central section, and recesses extending from the central opening and complementary to the cams,such that the locking member is movable between a first rotational position in which the cams of the locking member abut the seed disc and clamp the seed disc between the cams and the rear attachment surface, and a second rotational position, in which the cams of the locking member are aligned with the recesses of the seed disc and the seed disc is removable. State of the art

[0002] In the prior art, seed drills, which can distribute individual grains into an open furrow, are equipped with metering units, each comprising a seed disc. The seed discs, also called sowing discs, separating discs or metering discs, are connected to a rotary drive, and comprise openings into which the individual grains of the seed are absorbed. The absorbed grains are held by negative pressure in the openings, transported at a certain angle in the direction of rotation of the seed disc, and then finally released so that they can enter the furrow.

[0003] The seed discs are generally detachable from the rotary drive shaft, so that they can be replaced if necessary, after opening a cover, by another seed disc, which may have other distances and / or dimensions of the openings.

[0004] In the prior art, a support coupled to a shaft of the rotary drive is used for this purpose in the seeding machines manufactured by the applicant (see the brochure entitled “Valoterra, the new reference in terms of precision” of the company Ribouleau Monosem, printing mark 92800DE, page 7), which has a rear fixing surface for the seed disc and a central section with cams distributed around its circumference which intervene in complementary cavities in the disc. As a result, the disc is fixed to the support in the direction of rotation.

[0005] In the axial direction of the shaft, the fixing of the seed disc is carried out by a separate locking element, which is rotatably arranged relative to the holder around its central section and thus around the axis of the shaft, and is also equipped with cams whose dimensions in the circumferential direction and the axial direction correspond at least approximately to those of the cams of the holder.

[0006] In a first rotational position, the cams of the locking element rest against the disc and lock it firmly on the holder by clamping the seed disc between the locking element and the rear surface, and in a second rotational position, the cams of the locking element are aligned with the cams of the holder. Thus, the seed disc is locked in the first rotational position and removable from the holder in the second rotational position. The axial fixation of the locking element, in particular in the first rotational position, is achieved by a spring force in which a spring prepositions the locking element axially towards the mounting assembly relative to the central section of the mounting assembly. The operator can thus loosen the locking element from the seed disc against the spring force if necessary and move it between the two rotational positions.

[0007] A similar attachment of a seed disc to its shaft by means of a rotating handle, which is inserted through a corresponding opening in the seed disc and then turned to lock the seed disc, is described in EP 0 140 699. There, the handle moves along a ramp and clamps the seed disc with increasing force until it reaches a depression in the ramp, into which it is pulled by spring force to lock it there. By pulling the handle out of the depression, it can be turned in the opposite direction to remove the seed disc.

[0008] The removable attachment of the seed disc, presented in the previously cited "Valoterra" brochure and in EP 0 140 699, allows an operator to replace the seed disc relatively easily and quickly. However, the axial attachment with forced locking of the seed disc by spring force by the locking element has not proven reliable in all cases, because the side of the seed disc on which the locking element is located is subjected to a negative pressure which acts against the locking force of the spring and sometimes causes the locking element to detach from the seed disc, which sometimes results in the detachment of the seed element and the function of the dosing unit is no longer guaranteed Aims of the invention

[0009] The present invention aims to provide a dosing unit for a seeding machine, which does not have the drawbacks of the state of the art.

[0010] The present invention aims to provide a dosing unit for a seeding machine, which has improved operation, and increased operational reliability. Summary of the invention

[0011] The present invention relates to a metering unit for a seeding machine, having a seed disc rotatable about its axis by a drive, and comprising a number of openings distributed in its circumferential direction for receiving seeds, wherein the seed disc is removably connectable or connected by a mounting assembly to a shaft of the drive, the mounting assembly comprising a rear attachment surface for the seed disc, a central section and a separate locking element, which is equipped with cams and is rotatable relative to the central section, the seed disc comprising a central opening complementary to the central section and niches extending from the central opening and which are complementary to the cams,such that the locking element is movable between a first rotational position in which the cams of the locking element abut the seed disc and clamp the seed disc between the cams and the rear attachment surface, and a second rotational position, in which the cams of the locking element are aligned with the recesses of the seed disc, characterized in that the locking element is lockable to the central section by a fitted connection.

[0012] According to particular embodiments of the invention, the dosing unit according to the invention comprises at least one, or any suitable combination, of the following characteristics: - the adjusted connection comprises a clamping element coupled to the central section, which is movable between a first rotational position, in which it presses the locking element against the seed disc, and a second, loosened rotational position, - the clamping element is capable of pivoting between the first and second rotational positions about an axis extending radially to the axis of rotation of the seed disc and the shaft, - the clamping element is shaped in such a way that the area of ​​the clamping element, abutting the locking element, arrives in an intermediate position between the first and second rotation positions, closer to the seed disc than in the first pivoting position, - in which the clamping element is curved and pivotable at both ends, and the area of ​​the clamping element, abutting the locking element, is located adjacent to the ends, while the curved area can be used as a handle, - the pivoting axis of the locking element intersects the rotation axis of the seed disc and the area of ​​the clamping element, coming into contact with the locking element, and also extends on the side of the pivoting axis remote from the curved area, - the clamping element is hinged to a fastening element, which is irremovably coupled in the axial direction to the central section, - the locking element and / or the fixing element are fixed to a first or second cylindrical section integral with the central section, - the cams are distributed around the circumference of the central portion, the cams being complementary to the niches of the seed disc and configured to engage in the niches.

[0013] The present invention also relates to a row unit for a seeding machine with a dosing unit (24) according to the invention. Brief description of the figures

[0014] [Fig-1] is a schematic representation of a side view of a row unit of a seeder. [Fig.2] is a schematic representation of a perspective view of the metering unit of the row unit with the cover removed. [Fig.3] is a schematic representation of a perspective view of the row unit seed disc mounting assembly. [Fig.4] is an exploded view of [Fig.3]. [Fig.5] is a schematic representation of a cross-section through the mounting assembly with fixed clamping element. [Fig.6] is a schematic representation of a cross-section through the mounting assembly with the clamping element loosened. Detailed description of the invention

[0015] The present invention is defined by the claims.

[0016] It relates to a metering unit for a seeding machine, having a seed disc rotatable about its axis by a drive, and comprising a number of openings distributed in its circumferential direction for receiving seeds, wherein the seed disc is removably connectable or connected with a shaft of the drive by a mounting assembly, the mounting assembly comprising a fixing surface rear for the seed disc, a central section, and a separate locking element equipped with cams, and which is rotatable relative to the central section, the seed disc comprising a central opening complementary to the central section, and recesses extending from the central opening and complementary to the cams, so that the locking element is movable between a first rotational position in which the cams of the locking element abut the seed disc and clamp the seed disc between the cams and the rear attachment surface, and a second rotational position, in which the cams of the locking element are aligned with the recesses of the seed disc, and the seed disc is removable. The locking element can be locked to the central section by a fitted connection.

[0017] In other words, the locking element and thus also the seed disc are fixed by the form of elements in mechanical interaction with the central section, i.e. fixed in final shape. This avoids the disadvantages associated with the spring fixing mentioned at the beginning.

[0018] The adjusted connection may include a clamping member coupled to the central section, which is movable between a first rotational position, in which it presses the locking member against the seed disc, and a second, released rotational position.

[0019] The clamping element can be pivoted about an axis extending radially to the axis of rotation of the seed disc and the shaft between the first and second rotational positions.

[0020] The clamping element may be shaped such that the area of ​​the clamping element abutting the locking element is closer to the seed disc in the middle position between the first and second rotational positions than in the first rotational position.

[0021] The clamping element may be curved and pivotable at both ends, and the area of ​​the clamping element, abutting the locking element, may be located adjacent to the ends, while the curved area may be used as a handle.

[0022] The pivoting axis of the locking element may intersect the rotation axis of the seed disc, and the area of ​​the clamping element, coming into contact with the locking element, may also extend on the side of the pivoting axis remote from the curved area.

[0023] The locking element and / or the fastening element may be attached to a first or second cylindrical section securely connected to the central section.

[0024] Cams may be distributed around the circumference of the central section, cams which are complementary to the cavities of the seed disc and configured to intervene in the cavities of the seed disc.

[0025] One or more or all of the row units of a seeding machine may be equipped with a metering unit according to the invention.

[0026] [Fig.l] shows a row unit 12 for a seeding machine 10 in side view. The row unit 12 comprises a seeding unit 14 with a support frame 16, adjustable in height by a parallelogram suspension 18 and attached to a cross member 20 in a manner following the contour of the ground. The cross member 20, to which other row units 12, not shown here for reasons of clarity, are attached laterally side by side, can be attached to a frame or interface of an agricultural tractor (not shown) and is moved in operation in a V-direction, forward, over a field, to distribute seeds therein.

[0027] On the support frame 16 there are a seed container 22, a metering unit 24 for the seeds, a row cleaner 26, a furrow opener 28, a depth adjustment wheel 30 specifying the depth of the furrow, a pressure wheel 32 for pressing the seeds deposited by the metering unit 24 into the furrow provided by the furrow opener 28 and a pair of closing wheels 34 arranged, which finally closes the furrow.

[0028] [Fig. 2] shows the dosing unit 24 in an enlarged view and in the open position. The dosing unit 24 comprises a first housing part 36 in which a seed disc 38 is arranged. A second housing part 40 of the dosing unit 24 is shown in a disassembled position from the first housing part 36 and can be secured by locking elements 44 to the first housing part 36. The second housing part 40 comprises a tubing 42 which is connected to a pump which provides a vacuum in the second housing part 40 during operation. This vacuum is used to suck the seed particles, which are introduced into the dosing unit 24 through a conduit 48 from the seed container 22 or from a central seed container of the seeding machine (not shown), individually (in grain) into the openings 50 of the seed disc 38, which is driven by a drive 88 (cf.figures 3 and 4), until it is delivered by a seed tube (not shown) into the furrow.

[0029] A possible embodiment of a dosing unit is presented in document EP 2 810 546 A1, the disclosure of which is incorporated by reference into the present document.

[0030] The side of the seed disc 38 shown on the right in [Fig.2] is therefore located in a low pressure zone (called a vacuum). The drive 88 may comprise an electric motor or use a different powertrain.

[0031] The attachment of the seed disc 38 is achieved by a mounting assembly 46 which can be uncoupled, which is described in more detail with reference to Figures 3 and 4. While [Fig.3] shows the seed disc 38 in the attached state, it is shown disassembled in [Fig.4].

[0032] The mounting assembly 46 is used to detachably connect the seed disc 38 to a shaft 54 ​​of the drive 88, which in operation rotates the seed disc 38 about its axis of symmetry, so that successively different openings 50, distributed around the circumference of the seed disc 38, are exposed to individual particles of the seed and then sending them into the furrow.

[0033] The mounting assembly 46 includes a central section 56 which is connected to the shaft 54 ​​in a non-rotatable manner. The central section 56 is cylindrical in itself and has a diameter slightly smaller than that of a central opening in the seed disc 38, which surrounds the central section 56 when assembled.

[0034] Furthermore, the central section 56 includes a number of cams 72, four of which are shown, uniformly distributed around the circumference of the central section 56 in the embodiment shown. The seed disc 38 includes complementary niches 74, which receive the cams 72. Accordingly, the rotational position of the seed disc 38 is defined relative to the central section 56. By the shape, positioning and possibly the number of cams 72 and niches 74, the number of possible orientations of the seed disc 38 relative to the mounting assembly 46 may be limited, possibly to a single possible orientation, or as here, to four possible orientations. In the axial direction, the seed disc 38 ([Fig.4] left) is delimited by a fixing surface 58, which is generally rigidly connected to the central section 56 and extends radially outwards.

[0035] Further, a first cylindrical section 52 and a second cylindrical section 60 adjoin the central section 56 in the axial direction, directed away from the drive 88, each having smaller diameters than the central section 56 and thus firmly connected, wherein the diameter of the second cylindrical section 60 is even smaller than that of the first cylindrical section 52.

[0036] The cylindrical sections 52 and 60 may be manufactured in one piece with the central section 56, for example as a casting, or be firmly connected thereto, for example as a welded assembly.

[0037] On the first and second cylindrical sections 52 and 60, a locking element 62 is pushed in the assembled state of the mounting assembly 46, which locking element 62 has a cylindrical body having a centered opening, corresponding almost without play on the sections 52 and 60. Around the outer circumference of the body of the locking element 62, four cams 76 are distributed, the shape and dimensions of which approximately correspond to the cams 72 of the central section 56 in the radial and circumferential direction. The recesses 74 of the seed disc 38 are complementary to the cams 76 of the locking element 62 and the diameter of the body of the locking element 62 is slightly smaller than that of the central opening of the seed disc 38, so that the seed disc 38 can be moved over the locking element 62 if the cams 76 and the recesses 74 are aligned with each other.

[0038] The locking element 62 is free to rotate relative to the central section 56 about the axis of symmetry (axis of rotation of the shaft 54 ​​and the seed disc 38 and the mounting assembly 46) as long as it is not locked (as described below). Unlimited rotation (of 360° and more) may be provided, or the angle of rotation is limited to a lower value, for which corresponding features may be provided on the locking element 62 and on the cylindrical sections 52 and / or 60.

[0039] In order to couple the locking element 62 (and ultimately also the seed disc 38) in the axial direction with the central section 56, a fixing element 64 and a clamping element 66 are provided.

[0040] The fastening element 64 is fixed with its central opening to the second cylindrical section 60 and is fixed there at least in the axial direction (e.g. by a clamping ring 86, see [Fig. 5]) or also in the circumferential direction (e.g. by a pin passing radially through the second cylindrical section 60 and the locking element 64). The locking element 62 is therefore positioned sandwiched between the fastening element 64 and the central section 56 and / or the seed disc 38, but remains movable by a relatively small clearance in the axial direction (as long as the clamping element 66 is not effective). However, the fastening element 64 is rigidly coupled at least in the axial direction with the central section 56, as mentioned.

[0041] The clamping element 66 is in turn movable about a radially extending pivot axis (relative to the axis of rotation of the shaft 54 ​​and the seed disc 38 and the mounting assembly 46), which is defined by two pins 68, which lock the clamping element 66, serve as a handle for an operator, arc-shaped at its two ends on the fixing element 64, and which extend radially through the clamping element 66 and the fixing element 64. The clamping element 66 can be brought into the clamping position, as shown in [Fig. 4], or pivoted 90° about its pivot axis, in Figures 3 and 4 on the right, as shown in [Fig. 6].

[0042] The clamping element 66 is pivotally supported with its two ends by the pins 68 of the fixing element 64 and can be brought into its first rotational position, in which the clamping element 66 extends transversely to the axis of the seed disc 38, with its end sides adjacent to the pivot axis in abutment with the locking element 62, as shown in [Fig. 5]. In this position, it presses the locking element 62 against the seed disc 38 and fixes it there.

[0043] The clamping element 66 comprises the area 84 coming into abutment with the locking element 62. This area 84 is arranged in such a way that it performs a circular movement when pivoting the clamping element 66 around the pins 68, which initially increases the clamping effect when moving the clamping element 66 from the first pivoting position shown in [Fig. 5] by approximately 90° to the second (unclamped) clamping position shown in [Fig. 6], since the region 84 is located on both sides of the pins 68 and thus also on the side of the pivot axis separated from the arc-shaped region of the clamping element 66, and then reduced again. As a result, the clamping element 66 is forcibly locked in the first position (so-called eccentric mechanism).Said movement is made possible by a certain elasticity of the material of the clamping element 66, possibly also the material of the locking element 62 and / or the fixing element 64, which may be plastic, for example. Alternatively, or in addition, a spring could be provided for this purpose, for example between the locking element 62 and the seed disc 38.

[0044] Based on Figures 5 and 6, it is further recognizable that a section 78 of the shaft 54 ​​extends axially through the mounting assembly 46 and is secured to the outer end of the second section 60 by a nut 70. A spring 80 is mounted between a disc 82 coupled to the shaft 54 ​​and an inner shoulder disposed at the transition between the first and second cylindrical sections 52, 60. The nut 70 therefore contracts the spring 80 against its bias and the spring 80 allows some axial movement of the seed disc 38 relative to the housing 36, 40, on which the driver 88 is also supported.

[0045] In view of the above, the operation is as follows. In the first locked position of the clamping element 66, the cams 76 of the locking element 62 press the seed disc 38 against the attachment surface 58, as shown in FIGS. 3 and 5. If the clamping element 66 is brought into the second position, as shown in [Fig. 6], the clamping effect of the cams 76 of the locking element 62 is omitted and the latter can be rotated about its axis. The cams 76 can thus be aligned with the cams 72 of the central section 56. Then, the seed disc 38 can be removed and another seed disc 38 can be reattached in the reverse order of the steps.

[0046] After all this, a fitted fixation of the mounting assembly 46 is obtained in the first position of the clamping element 66, which also allows a fixation reliable when positioning the mounting assembly 46 in a vacuum area, unlike previously used designs based on spring force.

Claims

Claims

1. A metering unit (24) for a sowing machine (10), having a seed disc (38), rotatable about its axis by a drive (88) and comprising a number of openings (50) distributed in its circumferential direction for receiving seeds, wherein said seed disc (38) is removably connectable or connected by a mounting assembly (46) to a shaft (54) of said drive (88), said mounting assembly (46) comprising a rear attachment surface (58) for said seed disc (38), a central section (56) and a separate locking element (62), which is equipped with cams (76) and is rotatable relative to said central section (56), said seed disc (38) comprising a central opening complementary to said central section (56) and niches (74) extending from the central opening and which are complementary to said cams (76),such that said locking element (62) is movable between a first rotational position in which said cams (76) of said locking element (62) abut said seed disc (38) and clamp said seed disc (38) between said cams (76) and said rear attachment surface (58), and a second rotational position, in which said cams (76) of said locking element (62) are aligned with said recesses (74) of said seed disc (38), characterized in that said locking element (62) is lockable to said central section (56) by a fitted connection, said fitted connection comprising a clamping element (66) coupled to the central section (56), which is movable between a first rotational position, in which it presses the locking element (62) against the seed disc (38), and a second, loosened rotational position.,

2. A dosing unit (24) according to claim 1, wherein the clamping element (66) is pivotable between the first and second rotational positions about an axis extending radially to the rotational axis of the seed disc (38) and the shaft (54).

3. Dosing unit (24) according to claim 2, wherein the clamping element (66) is shaped such that the area (84) of the clamping element (66), abutting the locking element (62), arrives in a position, intermediate between the first and the second rotation position, closer to the seed disc (38) than in the first rotation position.

4. A dosing unit (24) according to claim 3, wherein the clamping element (66) is curved and pivotable at both ends, and the area (84) of the clamping element (66), abutting the locking element (62), is located adjacent to the ends, while the curved area can be used as a handle.

5. A dosing unit (24) according to claim 4, wherein the pivoting axis of the locking element (62) intersects the rotational axis of the seed disc (38) and the area (84) of the clamping element (66), coming into contact with the locking element (62), and also extends on the side of the pivoting axis remote from the curved area.

6. Dosing unit (24) according to any one of claims 1 to 5, wherein the clamping element (66) is hinged to a fixing element (64), which is axially irremovably coupled to the central section (56).

7. A dosing unit (24) according to claim 6, wherein the locking element (62) and / or the fixing element (64) are fixed to a first or second cylindrical section (52, 60) integral with the central section (56).

8. A dosing unit (24) according to any one of claims 1 to 7, wherein the cams (72) are distributed around the circumference of the central portion (56), said cams (72) being complementary to the niches (74) of the seed disc (38) and configured to engage in the niches (74).

9. Row unit (12) for a seeding machine (10) with a dosing unit (24) according to any one of the preceding claims.

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