WO1999055137A1

WO1999055137A1 - Arrangement for raising and lowering a tool in an agricultural implement

Info

Publication number: WO1999055137A1
Application number: PCT/SE1999/000665
Authority: WO
Inventors: Crister Stark; Mats Kjellsson; Lars Monzon; Lennart Larsson
Original assignee: Väderstad-Verken Ab
Priority date: 1998-04-24
Filing date: 1999-04-23
Publication date: 1999-11-04
Also published as: AU4300999A

Abstract

The invention relates to a device for raising and lowering a tool part (14, 54) forming part of an agricultural tool, comprising a fixture (12), which is arranged on a frame part connecting to the frame of the agricultural tool, and means (28, 56) for raising and lowering the tool part in relation to the fixture (12). The said means (28, 56) is flexible and is set up for adjustment of the tool part (14, 54) into predetermined positions in relation to the fixture (12). The invention also relates to a sowing share for use with such a device.

Description

_Arrangement for raising and lowering a tool in an agricultural implement

The present invention relates to a raising and

5 lowering device for a tool part forming part of an agricultural tool according to the preamble to Patent

Claims 1 and 18. The invention also relates to a sowing share for the device according to Claim 1.

Disc shares are used in sowing machines to

10 produce a furrow in the ground. A disc share comprises a sowing share and a disc which cooperate to produce the furrow in the ground. The sowing share further comprises a sowing tube through which material, such as seed or fertilizer, is conducted to the ground or down

15 into the furrow.

It is previously known to attach a sowing share to a share arm with the aid of a screw connection. A fixture is arranged on the sowing share, which fixture has a plurality of holes for the screw connection. The

20 holes are placed such that different adjustment positions for the sowing share are obtained depending on which holes are selected in fixing the sowing share to the share arm. The sowing share comprises a share tip and it is desirable for the share tip to bear

25 against ^'a disc which is arranged on the share arm. In order to achieve this, the known device has one or more spring washers, which are clamped in the screw connection.

In order to adjust the position of the known

30 device, the entire sowing share has to be unscrewed from the share arm only then afterwards to be screwed back tight in any one of the other holes in the fixture. At the same time, the tightening torque of the screw or screws is adjusted such that the desired

35 contact force from the sowing share against the disc is obtained. This is time-consuming and complicated, especially if a large number of sowing shares are to be adjusted at the same time, which is usual with sowing machines . - 2 -

The width of the known sowing share, viewed in the direction of travel of the sowing machine, is large, which means that the permeability, that is to say the ability of the sowing share to prevent soil and plant remnants from adhering to the sowing share, is limited.

It is previously known to arrange an adjustable, rigid harrow tooth in an agricultural tool, such as in a sowing machine. The harrow tooth is in this case arranged on the sowing machine with a fixture which allows the harrow tooth to be raised and lowered. The function of the harrow tooth is to loosen and work the soil before the material is placed in the ground. The known harrow tooth is adjustably connected to the sowing machine by means of a fixture. A plurality of holes or a groove are/is arranged in the harrow tooth, which holes or groove are/is arranged to cooperate with a screw or cotter connection together with holes arranged on a fixture for the harrow tooth. By loosening the screw or cotter connection and subsequently raising or lowering the harrow tooth in relation to the fixture, different positions for the harrow tooth can be obtained, which means that the depth at which the harrow tooth will operate under the ground surface can be adjusted. Once the desired adjustment position for the harrow tooth has been obtained, the harrow tooth is re-connected to the fixture by means of the screw or cotter connection.

The above-described raising or lowering of the harrow tooth is time-consuming and complicated, especially if a large number of harrow teeth are to be adjusted on a sowing machine. A plurality of components are also required, such as screws, nuts and cotters, which components are relatively small and can therefore disappear when the harrow teeth are adjusted. These components can also get damaged during use of the sowing machine, thereby rendering adjustment of the harrow teeth impossible. - 3 -

The object of the present invention is to achieve a device which allows quick and simple raising and lowering for a tool part forming part of an agricultural tool, such as a sowing share or a harrow tooth.

A further object is to achieve a tool part which forms part of an agricultural tool and has small dimensions and low weight.

Yet another object is to achieve a tool part which forms part of an agricultural tool and has good permeability .

This is achieved by a device of the type specified in the introduction, which incorporates the special features according to the defining clause of Patent Claim 1, 13 and 18 respectively.

Such a device allows quick and simple raising and lowering for the tool part, since only the flexible means fixes its adjustment position. With the aid of a flexible means which is arranged between the part forming part of the agricultural tool and the fixture, a device is obtained having a small width viewed in the direction of travel of the machine. High permeability is thereby obtained.

The invention will be described below in greater detail with the aid of illustrative embodiments shown in the appended figures, in which:

Fig. 1 shows a sowing share arranged on a share arm according to a first illustrative embodiment of the invention,

Fig. 2 shows a sowing share according to the first illustrative embodiment,

Fig. 3 shows a sowing share according to the first illustrative embodiment in a perspective view, obliquely from the rear, - 4 -

Fig. 4 shows a sowing share arranged on a share arm according to a second illustrative embodiment of the invention,

Fig. 5 shows a sowing share according to the second illustrative embodiment,

Fig. 6 shows a perspective view of a sowing share according to a third illustrative embodiment ,

Fig. 7 shows a perspective view of a device according to a fourth illustrative embodiment of the invention,

Fig. 8 shows a perspective view of the device according to the fourth illustrative embodiment in which a harrow tooth is being adjusted,

Fig. 9 shows a side view of a device according to a fifth illustrative embodiment of the invention,

Fig. 10 shows a side view of a device according to a sixth illustrative embodiment of the invention, and

Fig. 11 shows a top view of a fixture for the harrow tooth in the device according to the sixth illustrative embodiment of the invention,

Fig. 12 shows a perspective view of a device according to a seventh illustrative embodiment of the invention,

Fig. 13 shows a perspective view of a device according to the seventh illustrative embodiment, in which a harrow tooth is being adjusted, - 5 -

Fig. 14 shows a top view of a fixture according to the seventh illustrative embodiment of the invention,

Fig. 15 shows a detailed view of a harrow tooth according to the invention,

Fig. 16 shows a section along the line IV-IV in Fig. 15,

Fig. 17 shows a detailed view of an eighth illustrative embodiment according to the invention,

Fig. 18 shows a side view of the device according to a ninth illustrative embodiment, and

Fig. 19 shows a side view of the device according to a tenth illustrative embodiment.

Fig. 20 shows a side view of a sowing share according to an eleventh illustrative embodiment of the invention.

Fig. 21 shows a side view of a sowing share according to a twelfth illustrative embodiment of the invention.

In Fig. 1 a first embodiment of the invention is shown. A frame part such as a share arm 1 is provided at a first end 2 with a connection 4 which is intended to be connected to a frame on a sowing machine

(not shown) . At the other end 6 of the share arm 1 there is mounted a disc 8, which can rotate in conventional manner about an axis 10.

At the other end 6 of the share arm 1 there is also arranged a fixture 12 for a sowing share 14. The fixture 12 comprises two flanges 16, 18 which are each provided with a continuous hole 20, which holes are - 6 — made one right in front of the other, the one end of the sowing share 14 being guided through the holes 20.

The sowing share 14 has a sowing tube 22 for conducting material such as seed or fertilizer to the ground. The material is guided into the sowing share 14 by, for example, a hose 23 coupled to the sowing tube 22 (Fig. 3) . A share tip 24 arranged on the sowing tube 22 is set up to bear against the disc 8.

In the case of sowing and/or fertilizing, the sowing machine and hence the disc 8 and the sowing share 14 travel in the direction of the arrow P in Fig. 1. The disc 8 will in this case produce a furrow in the ground, in which furrow the material shall be placed. With the aid of the share tip 24, the furrow is kept open at the same time as the material is guided down into the furrow through a longitudinal opening 48 made in the lower end of the sowing tube. A hard-metal tip 26 is arranged on the share point 24 so as to reduce the wear on the share tip 24 from the ground. The adjustment of the position of the sowing share is achieved by a displacement of the sowing share 14 relative to the fixture 12 and hence also relative to the share arm 1 and the disc 8.

In order to enable a displacement of the sowing share 14 in relation to the fixture 12, the holes 20 in the fixture are larger than the sectional area of the sowing tube 22, so that the sowing tube 22 runs freely in the holes 20. The holes 20 can be round and the cross section of the sowing tube 22 round, which means that the sowing tube 22 is rotatable in the fixture 12. A spring, in the form of a leaf spring 28, is arranged between the sowing tube 22 of the share 14 and the fixture 12. The leaf spring 28 fixes the sowing share 14 relative to the fixture 12, which means that the sowing share 14 cannot be displaced in the fixture 12. On the other hand, the leaf spring 28 allows the sowing share 14 to rotate within the fixture 12, which is to be described in greater detail below. - 7 -

A fixing member in the form of a dowel 30 is arranged on one of the flanges 16 of the fixture 12. The dowel 30 is intended to cooperate with recesses in the form of a plurality of holes 32 arranged at a predetermined distance apart, which are cut in the leaf spring 28. There are also other options for fixing the leaf spring 28 to the fixture 12. For example, the leaf spring 28 can be provided with a plurality of folds which with their form lock the leaf spring 28 in different positions with the fixture 12.

By using a suitable tool or a hand to take hold of the leaf spring 28 and by prising this in the direction away from the fixture 12 and the dowel 30, the holes 32 in the leaf spring 28 will leave the dowel 30, whereupon the sowing share 14 is able to be freely displaced relative to the fixture 12. The sowing share is thereby able to be moved in the vertical direction.

Once the sowing share 14 has been displaced relative to the fixture 12 and a suitable position has been obtained, the leaf spring 28 is returned to its original position so that the dowel 30 is guided into a hole 32 corresponding to the chosen position.

On the sowing tube 22 of the sowing share 14 there is arranged a leaf spring fixture 34. This leaf spring fixture 34 is provided with a slot 36 into which the leaf spring 28 is introduced and fastened. In order to obtain good cooperation between the slot and the leaf spring 28, the leaf spring is bent at the end which is introduced into the slot 36. In Fig. 2 the sowing share 14 according to the first illustrative embodiment is shown. In the figure the slot 36 in the leaf spring fixture 34 is shown. The slot 36 is provided with two notches 38. This form of the slot 36 means that the leaf spring 28 can be rotated in relation to the leaf spring fixture 34 as soon as the holes 32 in the leaf spring 28 have left the dowel 30. This means that the leaf spring 28 does not need to be tensioned when the sowing share 14 is displaced relative to the fixture 12. - 8 -

In Fig. 3 the sowing share 14 is shown arranged on a share arm 1 according to the first illustrative embodiment in a perspective view viewed obliquely from the rear. The figure clearly illustrates how the leaf spring 28 is arranged and clamped between the sowing tube 22 and the fixture 12. The force from the leaf spring 28 acts upon the sowing share 14 and thereby brings the share tip 24 to bear against the disc 8 with a controlled force which is dependant upon the spring force of the leaf spring 28. In order to prevent the sowing share from being rotated out too far under extreme circumstances, a suitable stop 37 (Figs. 2 and 5) can be arranged on the sowing tube 22, which stop cooperates with a recess (not shown) in the fixture 12. The stop 37 prevents the sowing share 14 from rotating more than a predetermined, permitted angle of rotation. The stop 37 can also be arranged such that the share tip 24 ends up at a predetermined distance from the disc 8. A clearance is thereby formed between the share tip 24 and the disc 8.

In order to increase the lever arm between the share tip 24 and a line extending centrally through the holes 20 in the fixture, i.e. the centre of rotation of the sowing share 14, the sowing tube 22 is provided with a curve 40. According to the first embodiment, the sowing tube 22 comprises two essentially straight sections 42, 44 which, via the curve 40, extend out at an angle α, see Fig. 2, in relation to each other. The angle α should lie within the range 15° - 35°. Preferably the angle α is equal to 25°. Fig. 3 also illustrates how the sowing tube is provided with an opening 46 which is facing backwards in relation to the direction of travel. This backward-facing opening 46 ensures that the sowing tube 22 is not clogged up with soil or the like. A guide element 49 in the form of a plate can be arranged at the opening 46 to direct the material in the desired direction in the sowing share 14. According to a second embodiment of the invention, which is shown in Figs. 4 and 5, the sowing tube 22 is curved along its longitudinal direction with a radius r. As a result of this curvature, material of a certain type is prevented from leaving the sowing tube 22 through the backward-pointing opening 46. The material will then instead follow the curvature of the sowing tube 22 and leave the sowing tube 22 through the ground-facing opening 48. The lever arm between the centre of rotation of the sowing share 14 and the share tip 24 can also be increased by lengthening the share tip 24 in relation to the centre of rotation in order thereby to obtain a desired contact force between the share tip 24 and the disc 8. According to this construction, the sowing share 14 can be provided with a straight sowing tube 22. The lever arm can also be varied by an additional pair of dowels 30 being arranged on the fixture 12 at different distances from the centre of rotation of the sowing share 14. By placing the leaf spring 28 with one of its holes 32 on a dowel 30 which is arranged at a greater distance from the centre of rotation, the force by which the sowing share 14 bears against the disc 8 or the stop 37 is increased. In Figure 6 a perspective view is shown of a sowing share 14 according to a third illustrative embodiment in which the leaf spring 28 is connected to the sowing share 14 by means of a rivet connection 50. The rivet 52 extends through the leaf spring 28 and the leaf spring fixture 34 so that the leaf spring 28 can be rotated about the centre axis of the rivet 52 whenever the sowing share 14 is to be raised or lowered. Fig. 6 illustrates that the leaf spring 28 can be provided with a predetermined curved form. Such a form means than an essentially equally large spring force can be obtained in different positions of the sowing share 14. In a simpler construction the leaf spring 28 can be shaped essentially straight. - 10 - In Fig. 7 a perspective view is shown of a device according to a fourth illustrative embodiment of the invention. An essentially rigid spike in the form of a harrow tooth 54 is adjustably connected to a fixture 12, which is arranged on a frame part 1 such as a resilient arm 1 of a sowing machine. The fixture 12 comprises a first and second flange 16, 18, which are each provided with a hole 20 through which the harrow tooth 54 extends. A helical spring 56 is arranged between the flanges 16, 18 and connected to the second flange 18 through the introduction of an end of the helical spring 56 into a hole 58 intended for the helical spring 56 in the second flange 18. The other end of the helical spring 56 is bent to form a handle 58, which is to be described in greater detail below. The resilient arm 1 can be constituted by one of the arms of a planker or so-called crossboard (not shown) . A large number of arms are in this case arranged on the machine, a fixture 12 being arranged on each arm 1. The helical spring 56 is arranged between the flanges 16, 18 such that it extends between the holes 20 which are arranged in the flanges 16, 18 and which holes 20 are intended for the harrow tooth 54. The harrow tooth 54 will thus extend through the holes 20 and through the helical spring 56, as is shown in Fig. 7. The helical spring 56 is thus wrapped around the harrow tooth 54 and clamps around this in order to fix the harrow tooth 54 in a specific position.

By applying a force to the handle 58 of the helical spring 56, as is shown in Fig. 8, and rotating the handle 58 by an angle β about the centre line of the helical spring 56, which is coincident with the centre line of the harrow tooth 54, such that the diameter of the helical spring 56 increases, the harrow tooth 54 is released from the helical spring, which means that the harrow tooth 54 can be guided axially, according to the arrow A, through the holes 20 in the flanges 16, 18 and through the helical spring 56. A desired position for the harrow tooth 54 relative to - li the fixture 12 can thereby be obtained. This adjustment of the position of the harrow tooth 54 is carried out whenever the depth by which the harrow tooth 54 pokes down into the ground has to be altered. The soil- working part, i.e. the lower part of the harrow tooth 54, can be provided with a curved section 60, as is shown in Fig. 8. It is then possible to insert the harrow tooth 54 by rotating this according to the arrow B such that the curved section 60 is facing in a desired direction. The rotation of the harrow tooth 54 is made possible when a force is applied to the handle 58 of the helical spring 56, as is described above.

Instead of curving the end of the helical spring 56 in order thereby to form a handle 58, a separate handle, which is of a grip-friendly design, can be attached to the end of the helical spring 56. The arm 1 to which the fixture 12 is fastened can be suitably designed, for example by bending, such that a separate fixture 12 can be avoided. It is also possible to lengthen the flanges 16, 18 and/or design these with a considerable width such that a plurality of harrow teeth 54 can be arranged on the same fixture 12. By choosing a suitable thread diameter, pitch and diameter for the helical spring 56, an increased degree of flexibility in the working member can be obtained. In order to strengthen the grip of the helical spring 56 around the harrow tooth 54, the latter ca be provided with channels or grooves (not shown) , which preferably have the same pitch as the helical spring 56. In Fig. 9 a side view is shown of a device according to a fifth illustrative embodiment of the invention. According to this illustrative embodiment, the harrow tooth 54 can be inclined in a vertical plane. In Fig. 9 the harrow tooth 54 is shown in two different positions. The first, upper flange 16 is provided with two holes 20, 21 through which the harrow tooth 54 can optionally extend depending on the desired inclination of the harrow tooth 54. In order to alter the inclination of the harrow tooth 54, a force is - 12 - applied to the handle 58 of the helical spring 56 such that the harrow tooth 54 can be displaced axially through the spring 56 and the holes 20. The harrow tooth 54 can then be pushed out through one of the holes 20 in the first fixture 16 so as then to be inclined and guided into the second hole 21.

Fig. 10 shows a side view of a device according to a sixth illustrative embodiment of the invention. What differentiates the working member according to this illustrative embodiment from the fifth illustrative embodiment is that the harrow tooth 54 is provided with a recess 62 and that the holes 20, 21 in the first, upper flange 16 are interconnected by a groove 64, as is shown in a top view of the fixture 12 in Fig. 11. In order to alter the inclination of the harrow tooth 54, a force is applied to the handle 58 of the helical spring 56, after which the harrow tooth 54 is guided down through the holes 20, 21 in the flanges 16, 18 and through the helical spring 56 until the recess 62 in the harrow tooth 54 ends up level with the first flange 16. The recess 62 in the harrow tooth 54 is dimensioned such that the harrow tooth 54, at the recess 62, can pass through the groove 64 in the first flange 16. Once the harrow tooth 54 has been guided through the groove 64, it is pushed axially through the second hole 21 to the desired height. The harrow tooth 54 which has been described above has preferably a round cross section but other cross-sectional forms are also conceivable, such as square, triangular or rectangular cross section.

A harrow tooth 54 has been described above in connection with the fourth, fifth and sixth illustrative embodiments. The device according to the invention can nevertheless be applied to other tool parts, such as groove looseners or sowing shares, in which the helical spring 56 is wrapped around a spike or a sowing tube. It is also possible to connect other machine parts to the machine on which the fixture 12 and the helical spring 56 are arranged. - 13 -

It can be desirable for the sowing share or harrow tooth to be arranged in the fixture such that the sowing share or harrow tooth is prevented from being rotated in the fixture. The sowing share or harrow tooth will thereby acquire a predetermined position in relation to the fixture. Such a device for raising and lowering a tool part forming part of an agricultural tool comprises a fixture which is arranged on a frame part connecting to the frame of the agricultural tool and means for raising and lowering the tool part in relation to the fixture, the said means being flexible and set up for adjustment of the tool part into predetermined positions in relation to the fixture. The tool part is provided with members cooperating with the fixture in order to counteract rotation of the tool part in relation to the fixture. Such a device allows quick and simple raising and lowering for the tool part, since the flexible means fixes its adjustment position. The member arranged on the tool part ensures that the tool part always has the same direction in relation to the fixture.

In Fig. 12 a perspective view is shown of a device 101 according to a seventh illustrative embodiment of the invention. An essentially rigid spike in the form of a harrow tooth 102 is adjustably connected to a fixture 104, which is arranged on a frame part 106 such as a resilient arm 106 of a sowing machine. The fixture 104 comprises a first and second flange 108, 110, which are each provided with a hole 112 through which holes the harrow tooth 102 extends. A helical spring 114 is arranged between the flanges 108, 110 and connected to the second flange 110 through the introduction of an end of the helical spring 114 into a hole 116 in the second flange 110 intended for the helical spring 114. The other end of the helical spring 114 is bent to form a handle 118, which is to be described in greater detail below. The resilient arm 106 can be constituted by one of the arms belonging to a planker or so-called crossboard (not shown) . A large - 14 - number of arms are in this case arranged on the machine, a fixture 104 being arranged on each arm 106.

The helical spring 114 is arranged between the flanges 108, 110 such that it extends between the holes 112 which are arranged in the flanges 108, 110 and which holes 112 are intended for the harrow tooth 102. The harrow tooth 102 will thus extend through the holes 112 and through the helical spring 114, as is shown in Fig. 12. The helical spring 114 is thus wrapped around the harrow tooth 102 and clamps around this in order to fix the harrow tooth 102 in a specific position.

By applying a force to the handle 118 of the helical spring 114, as is shown in Fig. 13, and rotating the handle 118 by an angle β about the centre line of the helical spring 114, which is coincident with the centre line of the harrow tooth 102, such that the diameter of the helical spring 114 increases, the harrow tooth 102 is released from the helical spring, which means that the harrow tooth 102 can be guided axially, according to the arrow A, through the holes 112 in the flanges 108, 110 and through the helical spring 114. A desired position for the harrow tooth 102 relative to the fixture 104 can thereby be obtained. This adjustment of the position of the harrow tooth 102 is carried out whenever the depth by which the harrow tooth 102 pokes down into the ground has to be altered. The soil-working part, i.e. the lower part of the harrow tooth 102, can be provided with a curved section 120, as is shown in Fig. 13. The harrow tooth 102 is provided with members in the form of at least one longitudinal groove 122, which cooperates with projections 124 arranged in the holes 112 in the flanges. The number of projections 124 which are arranged in the holes 112 preferably corresponds to the number of grooves 122 in the harrow tooth 102. Nevertheless a plurality of grooves 122 can be arranged in the harrow tooth 102 and one or more projections 124 in the holes 112. This allows the harrow tooth 102 to be inserted in a plurality of - 15 - different positions or angles in relation to the fixture 104. The grooves 122 and the projections 124 counteract rotation of the harrow tooth 102 in relation to the fixture 104. Although the helical spring 114 holds the harrow tooth 102 in a constant grip such that rotation of the harrow tooth 102 in relation to the fixture 104 is prevented. During adjustment of the harrow tooth 102 in the vertical direction, when the helical spring 114 is rotated manually about the harrow tooth 102, the harrow tooth 102 will also however be rotated if there is no rotation-preventing member such as the grooves 122 and the projections 124. It can thereby be difficult to obtain a desired position for the harrow tooth 102 in relation to the fixture 104, viewed in the direction of rotation.

Fig. 14 shows a top view of the fixture 104 according to the seventh embodiment. The hole 112 is provided with two diametrically arranged projections 112, which have to cooperate with the grooves 122 in the harrow tooth 102.

Fig. 15 shows a detailed view of a part of a harrow tooth 102. The groove 122 is designed to cooperate with the projection 124 or the projections in the holes 112 in the fixture 104. Fig. 16 shows a section along the line IV - IV in Fig. 4. The grooves 122 are according to the shown embodiment diametrically arranged in the harrow tooth 102.

According to an eighth illustrative embodiment of the invention, as is shown in Fig. 17, the harrow tooth 102 is provided with a thread 126 arranged around the harrow tooth 102, which thread has preferably the same pitch as the helical spring 114 which secures the harrow tooth 102 to the fixture 104. The thread 126 increases the gripping capacity of the helical spring 114 about the harrow tooth 102.

Fig. 18 shows a ninth illustrative embodiment of the invention, in which the helical spring 114 is a double-wound helical spring which at a first end is - 16 - connected to one of the flanges 108 of the fixture 104 and at a second end is connected to the second of the flanges 110 of the fixture, a central region of the helical spring 114 forming a handle 118 which, when acted upon by an external force, allows the tooth 102 to be released from the helical spring 114 such that the tooth 102 can be raised and lowered in relation to the fixture 104.

To enable the helical spring 114 to be more easily handled on the fixture 104, the flanges 108, 110 of the fixture 104 are provided with guide elements 128, which extend at least partially into the centre hole 130 in the helical spring 114, which hole is shown in a tenth embodiment in Fig. 19. A harrow tooth 102 has been described above in connection with the seventh to tenth illustrative embodiments. The device according to these illustrative embodiments can nevertheless be applied to other tool parts, such as groove looseners or sowing shares, in which the helical spring is wrapped around a spike or a sowing tube. It is also possible to connect other machine parts to the machine on which the fixture and the helical spring are arranged.

In Fig. 20 an eleventh illustrative embodiment of the invention is shown in the form of a sowing share 132 for an agricultural tool, comprising a sowing tube 134 for conducting material such as seed or fertilizer to the ground; and a share tip 136, which is arranged on the sowing tube 134, the sowing tube 134 along its longitudinal direction comprising two sections 138, 140 having different extension directions. The sowing tube 134 is provided with at least one longitudinal groove 22, which is designed for cooperation with a projection 124 in a fixture 104 for the sowing share 132. The sections 138, 140 are essentially straight and arranged such that they extend out via a curve 142 at an angle α in relation to each other, which angle α lies in the range 15° - 35° and is preferably 25°. - 17 -

According to an twelveth illustrative embodiment of the invention, a section 140 of the sowing tube 134 is curved along its longitudinal direction with a radius r, as is shown in Fig. 21.

Claims

- 18 -PATENT CLAIMS

1. Device for raising and lowering a tool part (14) forming part of an agricultural tool, comprising a fixture (12), which is arranged on a frame part (1) connecting to the frame of the agricultural tool, and means (28) for raising and lowering the tool part in relation to the fixture (12), which said means (28) is flexible and is set up for adjustment of the tool part (14) into predetermined positions in relation to the fixture (12) and which said means (28) forms a fixable coupling between the tool part (14) and the fixture (12) , characterized in that the tool part (14) is a sowing share (14) for a sowing machine and in that the flexible means is a leaf spring which is set up to have a rotary effect upon the sowing share (14) in relation to the fixture (12) .

2. Device according to Claim 1, characterized in that the leaf spring (28) is arranged such that raising and lowering of the sowing share (14) is allowed by relocation of the leaf spring (28) from a pretensioned adjustment position, after which the sowing share (14) is displaced to an intended new adjustment position and finally the leaf spring (28) regains the pretensioned adjustment position.

3. Device according to Claim 1 or 2, characterized in that the leaf spring is elongated and comprises a plurality of fixing means (32) which are arranged to engage with fixing members (30) on the fixture (12) in order to fix the sowing share (14) in various positions in relation to the fixture (12) .

4. Device according to Claim 3, characterized in that the fixing means comprise a plurality of holes (32) arranged at a predetermined distance apart and in that the fixing member comprises a dowel (30) which can be pushed into the said holes (32) .

5. Device according to any of the preceding claims, characterized in that the sowing share (14) comprises a sowing tube (22) which is essentially O 99/55137 _ _{╧ç g} _ PCT/SE99/00665 circular transversely to its longitudinal direction, in that the fixture (12) comprises at least one hole (20) through which the sowing tube (22) extends and in that the sowing tube (22) is rotatable within the hole (20).

6. Device according to Claim 5, characterized in that a spring fixture (34) is arranged on the sowing tube (22), in which spring fixture (34) the one end of the leaf spring (28) is rotatably mounted.

7. Device according to Claim 6, characterized in that the spring fixture (34) is provided with a slot (36) in which the leaf spring (28) is arranged and in that the form of the slot (36) allows the leaf spring (28) to be rotated in relation to the spring fixture (34) .

8. Device according to Claim 6, characterized in that the spring fixture (34) is provided with a hole in which a fastening element (52) such as a rivet is arranged to connect the leaf spring (28) and in that the fastening element (52) allows the leaf spring (28) to be rotated in relation to the spring fixture (34) .

9. Device according to any of the preceding claims, characterized in that the sowing share (14) and the fixture (12) are interconnected by a joint which enables rotation of the sowing share (14) in relation to the fixture (12).

10 Device according to any of the preceding claims, characterized in that the sowing tube (22) along its longitudinal direction comprises two essentially straight sections (42, 44) which via a curve (40) extend out at an angle (╬▒) in relation to each other, which angle (╬▒) lies within the range 15┬░ - 35┬░ and is preferably 25┬░.

11. Device according to any of Claims 1-9, characterized in that the sowing tube (22) along its longitudinal direction is curved with a radius (r) .

12. Device according to any of Claims 1-11, characterized in that the sowing tube (22) along the whole of its longitudinal direction is essentially straight.

13. Sowing share for a device according to Claim 1, which sowing share comprises a sowing tube (22) for conducting material such as seed or fertilizer to the ground; and a share tip (24) which is arranged on the sowing tube (22), characterized in that a spring fixture (34) is arranged on the sowing tube (22) , in which spring fixture (34) the one end of the leaf spring (28) is rotatably mounted.

14. Sowing share according to Claim 13, characterized in that the spring fixture (34) is provided with a slot (36) in which the leaf spring (28) is arranged and in that the form of the slot (36) allows the leaf spring (28) to be rotated in relation to the spring fixture (34) .

15. Sowing share according to Claim 13 , characterized in that the spring fixture (34) is provided with a hole in which a fastening element (52) such as a rivet is arranged to connect the leaf spring

(28) and in that the fastening element (52) allows the leaf spring (28) to be rotated in relation to the spring fixture (34) .

16. Sowing share according to any of Claims 13-15, characterized in that the sowing tube (22) along its longitudinal direction is curved with a radius (r) .

17. Sowing share according to any of Claims 13-15, characterized in that the sowing tube (22) along the whole of its longitudinal direction is essentially straight .

18. Device for raising and lowering a tool part (14, 54) forming part of an agricultural tool, comprising a fixture (12), which is arranged on a frame part (1) connecting to the frame of the agricultural tool, and means (56) for raising and lowering the tool part in relation to the fixture (12), which said means (56) is flexible and is set up for adjustment of the tool part (14, 54) into predetermined positions in relation to the fixture (12) and which said means (56) forms a part of a coupling between the tool part (14, 54) and the fixture (12) , which coupling can be fixed - 21 - in predetermined positions, characterized in that the flexible means is a helical spring (56) which is wrapped around the tool part (14, 54) and in that the helical spring (56) is arranged such that raising and lowering of the tool part (14, 54) is allowed by relocation of the helical spring (56) from a pretensioned adjustment position, after which the tool part (14, 54) is displaced to an intended new adjustment position and finally the helical spring (56) regains the pretensioned adjustment position.

19. Device according to Claim 18, characterized in that a first end of the helical spring (56) is connected to the fixture and in that a second end of the helical spring comprises a handle (58) which, when acted upon by an external force, allows the tool part (14, 54) to be released from the helical spring (56) such that the tool part (14, 54) can be raised and lowered in relation to the fixture (12) .

20. Device according to any of Claims 18 or 19, characterized in that the fixture (12) comprises at least one hole (20) through which the tool part (14, 54) extends and in that the tool part (14, 54) is rotatable in the hole (20) .

21. Device according to Claim 20, characterized in that the fixture comprises a flange (16) which comprises the hole (20) and further holes (21) intended for the tool part (14, 54), which holes (20, 21) allow the tool part (14, 54) to be inclined into various positions .

22. Device according to any of Claims 18-21, characterized in that the tool part comprises an essentially rigid spike (54) such as a rigid harrow tooth, a grooved loosener or a sowing share (14) .