GB1573615A - Agricultural drill apparatus - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO AGRICULTURAL DRILL APPARATUS (71) I, COLIN JOHN COLLINS, of British Nationality, of Quarry Pit Farm, Inkberrow, Near Worcester, Worcestershire, do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to agricultural apparatus for drilling, that is sowing or depositing seed, fertilizer, or mixtures of seed and fertilizers.

On an agricultural scale the process of drilling involves the introduction of the material to be drilled into a plurality of side-by-side rows or channels in a prepared field. In practice, the drilling machine forms the drill rows, deposits the seed or other material and then at least initiates the covering in of the drill rows.

In practical applications of the process the machines have included chistle like arrangements commonly called coulters which are advanced into the soil to a desired depth and are then advanced with respect to the soil and in so doing produce the drill rows.

It is also known to use drilling machines having discs which act as coulters and which are freely rotatable upon individual shafts.

These disc coulters are so arranged that on advancing the machine the discs are effectively pulled through the soil. The frictional forces produced between the discs and the ground cause the discs to rotate and thereby cut into the ground and in so doing the discs form one side of a drill row. The other side of the drill row is formed by the leading part of the outlet nozzle of a seed delivery tube. This nozzle is shaped to form a coulter of the chistle type.

In practice it has been found that the disc type of coulter is prone to clogging when the disc is used in certain types of soil or under conditions in which the ground is wet and heavy, or is full of weed roots or stubble. This clogging prevents free rotation of the discs.

This in turn causes rapid wear of a trapped disc at the region where the disc is effectively trapped in the soil. In practice this wear takes the form of a flat at the periphery of the disc.

To remove such a flat it is usually necessary to grind the disc so as to restore the original shape. This operation is not always a successful solution since in order to remove a flat from a disc the overall diameter of the disc has to be reduced. However, since the discs are usually dished the removal of the flats also interfers with the operational shape of the disc so that it will not operate correctly as a coulter.

In otherwords, the formation of a flat on a disc effectively means a premature rejection of the disc as a usuable coulter.

According to a first aspect of the invention there is provided drill apparatus for depositing material into the ground, wherein at least one group of disc elements is arranged such that when the apparatus is in use the edges of the disc elements can engage with the ground such as to act as coulters able to part form drill rows for receiving said material, the disc elements of each group being carried by a common shaft so as to rotate therewith, and wherein each said disc element has associated therewith a non-rotatable coulter arrangement, each such non-rotatable coulter arrangement being such as to form the remainder of the drill row that is part formed by the associated disc element.

According to a second aspect of the invention there is provided drill apparatus for depositing material into the ground, wherein at least one group of disc elements is arranged so that the peripheral edges thereof can cut into the ground so as to part form drill rows when the apparatus is in use, each said disc element having an associated nonrotatable coulter arrangement which is so co-operable therewith as to form the remainder of the drill row that is part formed by the associated disc element, and wherein the disc elements of the or each group are connected to and constrained to rotate with a common shaft, therebeing a shaft for each said group of disc elements, each said shaft being rotatably mounted in associated resiliently loaded support means which enables the shafts to be selectively positionally adjusted to produce the required depth of penetration for the disc elements and coulter arrangements into the ground, and which allows each shaft and the disc elements carried thereupon to move under the resilient loading with respect to the selected position and thus the ground to accommodate surface undulations in the ground.

With this arrangement whenever any disc is upwardly displaced on encountering an obstacle during the operational advance, the weight of the shaft, discs and associated mounting, together with the resilient loading tend to return the disc being displaced towards the depth selected for the penetration into the soil.

Preferablv the supporting arrangements for the shafts include means for supporting the seed or other material dispensing tube outlet nozzles and also additional coulter means forming the remaining sides of the drill rows which are partially formed by the discs.

Conveniently, the coulter arrangements are formed as separate assemblies including a coulter and boot element, a scraper blade for scraping that side of the disc remote from the side with which the boot co-operates, and a support for the dispensing tube outlet nozzles.

Preferably the discs are releasably attachable to their associated shafts.

For a better understanding of the invention and to show how to carry the same into effect reference will r.ow be made to the accompanying drawings, in which Figure 1 is a perspective view of a generally schematic layout of an agricultural machine fitted with a schematic first form of an attachment of the invention, the Figure illustrating a portion of the complete machine.

Figure 2 is a perspective part sectional view to an enlarged scale of a detail of the attachment shown in Figure 1, Figure 3 is a schematic end view illustrating the overall arrangement of the attachment of the invention Figure 4 is a schematic plane view illustrating the overall arrangement of the attachment of the invention, Figure 5 illustrates as a perspective view a second embodiment of the attachment of the invention of Figure illustrating the main structural features, Figure 6 is a side view of a second embodiment of the detail shown in Figure 2, and Figure 7 is an end view of the detail shown in Figure 6.

Referring to the drawings Figure 1 illustrates a schematic representation of some of the main components of a drilling machine and is intended to indicate the positional relationships of a number of the major parts of a drilling machine with a view to facilitating understanding of the relationships between the apparatus of the invention and other parts of a drilling machine. It will be understood that in an actual machine many of the actual constructional details and the layout of the details would differ substantially from machine to machine and from the machine layout described hereinafter.

The machine shown includes a main frame 1 which is rectangular, and which is mounted upon wheels (not shown) by way of suspension brackets or the like (not shown). The frame 1 provides a platform for an elongate box or tank 2 for receiving the material such as grain or other seed, fertilizer, or mixtures thereof, to be sown or drilled. The tank 2 is so shaped that its interior forms a funnel like structure for aiding the gravity feed of the contents downwards towards an outlet region 3. This outlet region 3 includes a plurality of separate outlet openings 4 which are spaced along the length of the tank.

A rotatable feed element (not shown) co-operates with each opening 4 to provide a controlled feed of the seed or other material from the tank outlet openings. These rotatable elements are carried upon a common shaft (not shown) which is conveniently driven from a chain or shaft drive receiving its operational drive from the main wheels in such manner that the feed of the material is related to the rate of travel of the machine across a iield. The rotatable feed elements are conveniently provided with arrangements for enabling adjustment of the feed rates in relation to the rate of machine travel.

Each of the outlet openings 4 connects with a seed feed tube 5 which can be of a flexible tubing or of a telescopic tube construction, which in the arrangement shown in the Figure 1 is directed rearwardly of the machine to be connectable with an associated seed tube outlet nozzle 6.

In practice. in the case of the telescopic tube arrangement several lengths of tube, for example. three or four are slidably interconnected to each other, and the top end of the upper most tube is pivotaily or otherwise flexibly connected to the machine frame or tank so as to be able to receive the material from the associated opening 4. The lower end of the lower tube of the arrangement is engageable with the inlet end of the nozzle 6.

The attachment of the invention includes at least two groups of coulter discs 7. Each such group of discs 7 is provided own its own shaft 8. A coulter arrangement 9 is associated with each disc 7. Each arrangement 9 includes a coulter boot 10, a scraper blade 11 and the nozzle 6.

Referring now to Figure 2 this shows to an enlarged scale a schematic representation of a first construction of one of the coulter arrangements 9. As will be seen the coulter disc 7 is dished and is attached to the shaft 8 by way of a releasable coupling 12. This coupling 12 can be a wedge type, a keyed type, a bolted type or other suitable means by which the discs 7 can be securly attached to the associated shaft so as to be readily removable when necessary. With this arrangement the advancing movement of the drilling machine ensures that all of the discs 7 are simultaneously rotating with the associated shaft and that it is not possible for individual discs to cease rotation, as a result of clogging by soil or rubbish such as fine roots, weeds or the like so long as the disc coupling arrangements are functioning correctly.

The scraper 11 is shaped so as to be able to co-operate with the concave side of the disc 7 and thus comprises a shaped blade 13 having a portion, namely the edge 14 which is generally radially directed of the adjacent concave face 15 of the disc 7 and is profiled so as to conform to the dishing of the disc. The blade 13 is carried from an integral arm part 16 which is secured to a supporting bracket 17 whose mounting will be discussed hereinafter.

The nozzle 6 is supported by a U-shaped bracket (not shown) in Figures 1 or 2) which is itself connected to the bracket 17 such that the plane of the U is substantially radially directed of the associated disc 7 thereby effectively forming a guard for the rear of the associated disc.

It will be understood that the outlet nozzle 6 will be shaped as required to ensure the optimim feed of material through the nozzle.

The nozzle 6 is located between the convex side of the disc 7 and the coulter boot 10 which latter is conveniently carried from the U-shaped bracket or from the nozzle itself.

The boot 10 is shaped so as to be able to cut into the ground at a location to the rear of the region at which the disc 7 initially enters into the ground. This cutting action will be considered in more detail hereinafter. In addition, the coulter boot 10 is provided with an edge 19 which is arranged to act as a scraper which is able to co-operate with the adjacent convex side 18 of the associated disc 7.

Each shaft 8 is journalled in a bearing unit (not shown) carried at one end of each of a pair of frame members 20 and 21, whose other ends are pivotally connected to lugs 22 and 23 respectively provided on the main frame 1. Conveniently each shaft 8 is hollow and its ends are adapted to provide stub axles which engage with the bearing units. Conveniently the bearing units are self aligning ball or roller bearings.

Each of the frame members 20 and 21 is connected by means of resilient shock absorber units 24 to a transverse beam 25 which bridges both of said shafts and associated discs 7. The shock absorbers 24 allow the shafts to float upwardly and downwardly with respect to the transverse beam 25 and thus the frame 1.

The transverse beam 25 is connected to two further beams 26 which are releasably connected to the main frame 1 by means of bolts 27. The connections between the beams 26 and the transverse beam 25 are by way of screw adjuster units 28. Each of the units 28 has a handle for facilitating manual adjustment of the beam positionally relative to the beam 26.

Each pair of frame members 20 and 21 is interconnected by an associated transverse beam 30 which serves to provide a support for the brakckets 17 of the associated coulter arrangement 9. If desired, the beam 30 can also provide the support for the lower ends of the corn tubes 5 which connect with the associated nozzles 6.

As can be seen from Figure 3, these beams 26 and their associated adjuster units 28 are symmetrically spaced with respect to the overall length of the beam 25 and thus the length of the frame 1.

The adjuster units 28 enable the beam 25 to be readily moved up or down relative to the main frame and thus relative to the ground over which the machine travels. In other words the units 28 can be operated so that the coulter arrangements are clear of the ground, for example, for cleaning, transportation from field to field, turning at the end of a row and the like. In addition, the adJusters make it possible for the depth of penetration of the coulter discs 7 and boots 10 into the ground to be selectively controlled so that a controlled depth of drilling is possible.

In addiction, the shock absorbers 24 allow a floating action of the coulter arrangements relative to the beam 25 which enables the machine to overcome obstacles and the accommodate variations in the levels of the soil surface being transversed by the machine.

A particular construction of the attachment of the invention is schematically shown in general outline in Figure 5. As will be seen the attachment includes a first disc shaft Journalled in brackets 31 provided one at each end of a first support bar 32, a second disc shaft 8 journalled in brackets 33 provided one at each end of a second support bar 34. The bars 32 and 34 are interconnected in end-to-end relationship by a beam 35 which bridges the separation between the bars 32 and 34. The beam 35 is connected to the bars 32 and 34 by way of resiliently loaded arrangements 36 which allow the bars 32 and 34 separately to move up and down with respect to the beam 35.

The pressure exerted by the springs that produce the loading 'can be controlled by adjuster nuts or the like (not shown).

As will be seen from the Figure 5 the left hand shaft 8 carries one more disc than the right hand shaft. In practice, the number of discs actually provided upon a shaft is related to the overall width of the machine to which it is desired to mount the attachments of the invention. As can be seen in the Figure there are eight discs on the left hand shaft 8 and seven on the right hand shaft 8.

A support bar 37 is located on the outer end of the bar 32 and a similar bar 38 is provided at the outer end of the bar 34. The free ends of the bars 37 and 38 are intended to be pivotally connected to the main frame or other convenient part of the machine by means of pivot brackets (not shown). The inner ends of the bars 32 and 34 are effectively connected to the main frame by links 21 which connect to the main frame and to the brackets 31 and 33. The pivot axes of the links and the bars 32,34 and 39 lie on a common line. This allows the assembly to move about a common axis.

The beam 35 is provided with two support bars 39 spaced inwardly from the ends of the beam which are intended to be pivotally connected to further mounting brackets (not shown) which are provided on the main frame. These bars provide for the main depth control for the drilling by the machine.

In practice. it is desirable for the shafts to be slightly inclined relative to each other, as has been schematically shown in Figure 4. In the construction of Figure 5 this relative angling of the shafts 8 is obtained by suitablv dimensioning of the bars 37 and 38 and the links 21.

Arrangements (not shown) are provided for supporting the beam 35 at a required position relative to the machine. Conveniently, the beam has fittings (not shown) which enable the whole assembly to be resiliently loaded relative to the machine and also to enable the required drilling depth to be set.

It is convenient for the bars 32 and 34 to provide the anchorages for the corn tubes nozzles 6 and the coulter and scraper arrangements 9.

A modified form of such arrangements are shown in Figures 6 and 7. As can be seen from these Figures the modified form of the coulter arrangements includes a tube 40 having a plate 41 attached to its upper end and a bracket unit 42 attached to the lower end.

The plate 41 is provided with apertures 43 which locate the legs of a U-bolt (not shown) which is used to attach the plate 41 and thus the tube 40 and unit 42 in a required position with respect to the associated disc shaft bars 32 and 34. A bracket 44 attached to the upper end of the nozzle 6 is connected to the plate 41. The nozzle is so curved at its upper end that it inclines forwardly to receive the corn feed tubes 5. The lower end of the nozzle 6 is generally vertical and is shaped to provide a feed spout for material being delivered therethrough.

The unit 42 includes a side plate 47 and a back plate 48. In use the plate 41 is so mounted on the bars 32 and 34 that the corn tube nozzle 6 lies on the convex side of the associated disc 7 and so that the plate 48 lies behind the disc.

The coulter boot 10 is carried from the side plate 47 and comprises a shaped plate 49 which is so shaped and angled with respect to the side plate that it inclines generally towards the convex face 18 of the associated disc and with its front or formost edge 50 closely adjacent to the face 18. The edge 50 has a curvature which conforms to the profile of the disc. The shaping is such that a chamber is provided which is effectively closed at the front that is at the edge 50 and into which the lower end of the nozzle 6 projects. This chamber is open at the rear end.

The bottom 51 of the plate 49 and the edge region are intended to cut into the ground so as to form the other side of the drill row being formed by the disc.

It will be understood that the plate 49 in conJunction with the disc face 18 allows material to fall from the nozzle and to drop into the drill formed bv the plate and disc without impediment.

The co-operation of the plate 49 with the convex face of the disc also provides for a scraping effect.

A scraper blade 52 which is intended to provide a scraping action with respect to the concave face of the disc is connected to the rear plate 48 of the unit 42. The blade 52 has a limb 53 which is ad;ustabiy mountable on the plate 48, and which has ribs which engage with the top and bottom edges of the plate thereby to positionall, locate the scraper 52.

The actual blade has a shaped edge 54 which is so curved as to conform to the concave shape of the adjacent face of the disc.

The discs are releasably connected to the shafts 11 by means of a triangular mounting plate, one for each disc. welded or otherwise secured to the shaft so that the plane of the plate is perpendicular to the shaft axis. Each disc has a triangular cut-out which allows the discs to be pasted along the shaft. A series of bolt holes is formed in the discus therebeing a hole at each corner of the plate. Corresponding holes are provided in the disc central section, these holes being located midway along the length of fhe sides of the cut-out.

The disc is secured to the shaft plate by suit able bolts and nuts.

The dishing of the disc is, in a preferred construction such that radius of curvature of the dishing is substantially the same or the same as the diameter of the disc. As has been mentioned the disc has a flat central section for the above described mounting purposes.

It will be understood that when any disc encounters an obstacle during the advance of the machine the obstacle tends to lift the disc.

However, since all of the discs are carried upon a shaft, in the case of each group of discs, common to all of the discs of the group the total weight of the shaft and its associated mounting arrangements in conjunction with the resilient loading provided by the shock absorbers tends to push the discs being lifted towards the preset level and in so doing negates the effect of the obstacle.

In order to counteract any twisting effect which could be exerted upon the direction of advance of a tractor pulling the machine as a consequence of the dishing of the discs 7 the discs of the left hand shaft face in the opposite direction from those on the other shaft.

This is clearly shown in Figures 3 and 4.

In addition the shafts 8 are slightly angled as has been previously mentioned as a means of counteracting twisting motion that may be produced by the dishing of the discs.

In practice, the relative setting of the discs and the associated boot is such that the disc is located in advance of the leading edge or corner of the coulter boot 10 by a distance substantially equal to one third of the diameter of the disc 7. Furthermore, the said relative positioning in con unction with the shaping (dishing) and angling of the disc with respect to the direction of advance of the machine is such that the disc coulter is able to penetrate or cut into the ground in advance of the position at which the boot penetrates the ground.

This combination of factors is such that the advancing disc initiates the formation of a drill row by displacing soil to one side in a manner somewhat similar to the effect produced in water by the prow of a ship, and the coulter boot or plate forms the other side of the drill row.

It will be understood that means (not shown) are usually provided for covering-in the drill rows after the seed or fertilizer has been deposited into the drill rows. Such covering-in means can be effected by any of the conventionally used arrangements, and can either be incorporated in the drilling machine or separate therefrom.

In an alternative arrangement of the shaft structure each disc 7 can include a hub arrangement which is engageable on, for example, a square section shaft therebeing suitable spacers located between each ad;a- cent pair of discs so as to obtain the desired separation of the drill rows.

If desired the shafts 8 can be positively driven as the machine advances. This drive can be effected by a chain or shaft drive from the main wheels of the machine.

It will be noted that the above described attachments can be connected to any convenient machine having the suitably spaced pivot brackets or lugs.

WHAT I CLAIM IS: 1. Drill apparatus for depositing material into the ground, wherein at least one group of disc elements is arranged such that when the apparatus is in use the edges of the disc elements can engage with the ground such as to act as coulters able to part form drill rows for receiving said material, the disc elements of each group being carried by a common shaft so as to rotate therewith, and wherein each said disc element has associated therewith a non-rotatable coulter arrangement, each such non-rotatable coulter arrangement being such as to form the remainder of the drill row that is part formed by the associated disc element.

2. Drill apparatus for depositing material into the ground, wherein at least one group of disc elements is arranged so that the peripheral edges thereof can cut into the ground so as to part form drill rows when the apparatus is in use, each said disc element having an associated therewith a nonrotatable coulter arrangement with is so co-operable therewith as to form the remainder of the drill row that is part formed by the associated disc element, and wherein the disc elements of the or each group are connected to and constrained to rotate with a common shaft, therebeing a shaft for each said group of disc elements, each said shaft being rotatably mounted in associated resiliently loaded support means which enables the shafts to be selectively positionally adjusted to produce the required depth of penetration for the disc elements and coulter arrangements into the ground and which allows each shaft and the disc elements carried thereupon to move under the resilient loading with respect to the selected position and thus the ground to accommodate surface undulations in the ground.

3. Apparatus as claimed in claim 2, wherein each disc element shaft is rotatably carried by a support beam which has bracket elements connected thereto and which are directed transversely of the beam, and wherein the free ends of the bracket elements are adapted for pivotal connection to a main frame or body of said machine.

4. Apparatus as claimed in claim 3, wherein each said support beam is resiliently connected to a further beam which is itself adapted for connection to the frame or body of the machine.

5. Apparatus as claimed in claim 4, wherein the further beam is common to two

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (19)

**WARNING** start of CLMS field may overlap end of DESC **. able bolts and nuts. The dishing of the disc is, in a preferred construction such that radius of curvature of the dishing is substantially the same or the same as the diameter of the disc. As has been mentioned the disc has a flat central section for the above described mounting purposes. It will be understood that when any disc encounters an obstacle during the advance of the machine the obstacle tends to lift the disc. However, since all of the discs are carried upon a shaft, in the case of each group of discs, common to all of the discs of the group the total weight of the shaft and its associated mounting arrangements in conjunction with the resilient loading provided by the shock absorbers tends to push the discs being lifted towards the preset level and in so doing negates the effect of the obstacle. In order to counteract any twisting effect which could be exerted upon the direction of advance of a tractor pulling the machine as a consequence of the dishing of the discs 7 the discs of the left hand shaft face in the opposite direction from those on the other shaft. This is clearly shown in Figures 3 and 4. In addition the shafts 8 are slightly angled as has been previously mentioned as a means of counteracting twisting motion that may be produced by the dishing of the discs. In practice, the relative setting of the discs and the associated boot is such that the disc is located in advance of the leading edge or corner of the coulter boot 10 by a distance substantially equal to one third of the diameter of the disc 7. Furthermore, the said relative positioning in con unction with the shaping (dishing) and angling of the disc with respect to the direction of advance of the machine is such that the disc coulter is able to penetrate or cut into the ground in advance of the position at which the boot penetrates the ground. This combination of factors is such that the advancing disc initiates the formation of a drill row by displacing soil to one side in a manner somewhat similar to the effect produced in water by the prow of a ship, and the coulter boot or plate forms the other side of the drill row. It will be understood that means (not shown) are usually provided for covering-in the drill rows after the seed or fertilizer has been deposited into the drill rows. Such covering-in means can be effected by any of the conventionally used arrangements, and can either be incorporated in the drilling machine or separate therefrom. In an alternative arrangement of the shaft structure each disc 7 can include a hub arrangement which is engageable on, for example, a square section shaft therebeing suitable spacers located between each ad;a- cent pair of discs so as to obtain the desired separation of the drill rows. If desired the shafts 8 can be positively driven as the machine advances. This drive can be effected by a chain or shaft drive from the main wheels of the machine. It will be noted that the above described attachments can be connected to any convenient machine having the suitably spaced pivot brackets or lugs. WHAT I CLAIM IS:

1. Drill apparatus for depositing material into the ground, wherein at least one group of disc elements is arranged such that when the apparatus is in use the edges of the disc elements can engage with the ground such as to act as coulters able to part form drill rows for receiving said material, the disc elements of each group being carried by a common shaft so as to rotate therewith, and wherein each said disc element has associated therewith a non-rotatable coulter arrangement, each such non-rotatable coulter arrangement being such as to form the remainder of the drill row that is part formed by the associated disc element.

2. Drill apparatus for depositing material into the ground, wherein at least one group of disc elements is arranged so that the peripheral edges thereof can cut into the ground so as to part form drill rows when the apparatus is in use, each said disc element having an associated therewith a nonrotatable coulter arrangement with is so co-operable therewith as to form the remainder of the drill row that is part formed by the associated disc element, and wherein the disc elements of the or each group are connected to and constrained to rotate with a common shaft, therebeing a shaft for each said group of disc elements, each said shaft being rotatably mounted in associated resiliently loaded support means which enables the shafts to be selectively positionally adjusted to produce the required depth of penetration for the disc elements and coulter arrangements into the ground and which allows each shaft and the disc elements carried thereupon to move under the resilient loading with respect to the selected position and thus the ground to accommodate surface undulations in the ground.

3. Apparatus as claimed in claim 2, wherein each disc element shaft is rotatably carried by a support beam which has bracket elements connected thereto and which are directed transversely of the beam, and wherein the free ends of the bracket elements are adapted for pivotal connection to a main frame or body of said machine.

4. Apparatus as claimed in claim 3, wherein each said support beam is resiliently connected to a further beam which is itself adapted for connection to the frame or body of the machine.

5. Apparatus as claimed in claim 4, wherein the further beam is common to two

of said shaft support beams.

6. Apparatus as claimed in claim 4 or 5, wherein the resilient loading is selectively adjustable.

7. Apparatus as claimed in claim 4, 5 or 6, wherein the relative positioning of the further beam and the associated support beam is selectively adjustable.

8. Apparatus as claimed in claim 4, 5, 6 or 7, wherein the further beam is substantially rigidly coupled to the frame or body of the machine.

9. Apparatus as claimed in claim 8, wherein the rigid coupling is by way of further brackets extending transversely of the further beam and the support beams.

10. Apparatus as claimed in claim 4, 5, 6 or 7, wherein the further beam is pivotally connected to the machine frame or body.

11. Apparatus as claimed in any one of claims 3 to 10, wherein the shaft support beams are arranged to support seed or other material dispensing guide means which latter are arranged so as to deposit seed or other material into the drill rows.

12. Apparatus as claimed in any one of claims 2 to 10, wherein the shaft support beams include means for supporting seed or other material dispensing guide means and also said non-rotatable coulter arrangements.

13. Apparatus as claimed in any one of claims 2 to 12, wherein the non-rotatable coulter arrangements each include a coulter and boot element, a scraper blade for scraping the side of the associated disc element remote from the side thereof with which the boot element co-operates, and a support for a tubular nozzle serving as the seed or other material dispensing guide means.

14. Apparatus as claimed in claim 13, wherein the boot element is adapted to provide a scraper edge for co-operation with the ad acent face of the associated disc element.

15. Apparatus as claimed in any one of the preceding claims. wherein the disc elements are dished in such manner as to provide a relativelv flat central zone.

16. Apparatus as claimed in any one of the preceding claims, wherein the disc elements are so dished that the radius of curvature of the disc element is substantially equal to the diameter of the element.

17. Apparatus as claimed in any one of the preceding claims, wherein the disc elements are releasably attachable to the associated shaft by providing a non-circularly shaped plate on the shaft and a complementarily shaped aperture in the central zone of the disc, the arrangement being such that in a first position of the disc element relative to a plate the plate will pass through the aperture, and in a position different from the first the disc element can be attached to the plate.

18. Apparatus as claimed in claim 17, wherein the plate has a triangular periphery and the disc element has a triangular aperture in its central zone.

19. Apparatus for attachment to or for incorporation in an agricultural machine for depositing material into the ground, constructed and arranged to operate, substantially as hereinbefore described with reference to Figures 1 to 4 or Figures 5, 6 and 7 of the accompanying drawings.