GB2064491A

GB2064491A - Dispensing seeds or fertiliser

Info

Publication number: GB2064491A
Application number: GB8037499A
Authority: GB
Original assignee: Hestair Farm Equipment Ltd
Current assignee: Hestair Farm Equipment Ltd
Priority date: 1979-12-01
Filing date: 1980-11-21
Publication date: 1981-06-17
Also published as: GB2064491B

Abstract

A dispensing roller 52 for use in the seed and fertiliser dispensing mechanism of an agricultural seed drill 10 comprises a resilient body of e.g. non-expanded polyurethane mounted for rotation by a drive, and having on its outer surface a series of feed formations 62 of generally wedge- shaped cross-section, the feed formations being arranged with the thin end 64 of each formation adjacent the thick end 66 of the next formation so that the profile of the roller, as viewed in the direction of its axis 54 is similar to the axial profile of a ratchet wheel. The roller dispenses seeds or fertiliser at a nip and is formed with a central band 78 for dispensing small seeds, and the feed formations on opposite sides of the slow rate band are circumferentially offset from each other. Axially extending internal recesses 92 and 94 are formed in the roller to provide greater resilience for accommodating a large range of seed sizes. <IMAGE>

Description

SPECIFICATION Agricultural dispensing mechanisms This invention relates to agricultural dispensing mechanisms for dispensing particulate material, to dispensing rollers for such dispensing mechanisms, and to agricultural implements incorporating such dispensing mechanisms for delivering to the ground agricultural particulate material such as seeds, fertilisers, herbicides, insecticides, nematicides, fungicides, slug pellets and other pesticides. Examples of such implements are seed drills, seed and fertiliser drills, fertiliser dispensers for precision row crops, planters such as planters for maize, soya beans, potatoes etc., and rotary cultivators adapted to plant row crops.

More particularly, this invention relates to agricultural dispensing mechanisms comprising a resilient dispensing roller to dispense the agricultural particulate material.

Most of the previous proposals relating to dispensing mechanisms having a resilient dispensing roller have involved the use of a roller of foam rubber or sponge rubber (i.e. rubber expanded by gas bubbles) formed with a cylindrical surface which engages the material to be dispensed and carries it through a nip and thereby dispenses it.

We have tested dispensing rollers of expanded rubber in agricultural row crop implements such as seed drills, but the high standards of accuracy, consistency, and reproduceability of performance expected of such implements has highlighted certain operational disadvantages of such rollers so far as these particular qualities are concerned, these disadvantages being accentuated by certain seed dressings and by the carry-over effect of such dressings when changing from one seed (and its dressing) to another.

However, resilient roller dispensing mechanisms of the kind disclosed in British Patent No. 1,525,566 have such significant inherent technical advantages over alternative mechanisms having rigid rollers of the peg or fluted type, that the provision of an improved resilient roller in which some or all of the above mentioned disadvantages are overcome, would be a valuable contribution to the art.

We have also tested resilient roller dispensing mechanisms modified in various ways to improve the frictional grip of the roller on the material to be dispensed. The provision of a high friction surface on the rollers does not solve the problem. The use of two in-running resilient rollers does improve performance somewhat, but the cost and space penalties associated with the provision of a second roller for each crop row (or two extra rollers per row in the case of a combined seed and fertiliser drill) are prohibitive.

An object of the invention is to provide a resilient dispensing roller and a dispensing mechanism incorporating such a roller, having improved consistency of performance.

According to the invention there is provided a dispensing roller suitable for use in an agricultural dispensing mechanism for dispensing agricultural particulate material in which the roller is to be rotatably mounted to cooperate with a dispensing member to define a nip through which particulate material is dispensed during use; wherein the dispensing roller comprises a body of resilient material having formed on its outer surface a series of feed formations of generally wedgeshaped cross-section, the feed formations being arranged with the thin end of each formation adjacent the thick end of the next formation.

The invention also provides an agricultural dispensing mechanism for dispensing agricultural particulate material comprising a dispensing roller as defined in the preceding paragraph, and a dispensing member mounted to cooperate with the dispensing roller in defining a nip to which, in use, agricultural particulate material to be dispensed is supplied, the dispensing roller being mounted for rotation by a drive and being effective when rotated to dispense particulate material through said nip.

Preferably the profile of the dispensing roller as viewed in the axial direction of the roller is similar to the axial profile of a ratchet wheel, and the thick end of each feed formation provides an upstanding feed face on the surface of the roller, the direction of rotation of the roller in use being such that said feed face pushes material to be dispensed, through said nip. Ribs and grooves extending parallel to the axis of rotation of the roller may be provided on said feed formations.

Two sets of said feed formations may be provided, the formations of one set being circumferentially offset from the formations of the other set. A central slow rate band may be provided between said two sets of seed formations for dispensing materials at a relatively slow rate. The central slow rate band may be formed with a series of slow rate feed formations of generally wedge-shaped cross-section, the depth of the feed formations on the slow rate band being less than that of the feed formations on the remainder of the surface of the dispensing roller.

The feed formations on the central slow rate band may each be formed with ribs and grooves in the region of the thick ends of the feed formation.

Furthermore the slow rate band feed formations may be circumferentially offset with respect to the feed formations on each side of the slow rate band.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 shows a perspective view from the front of an agricultural seed drill incorporating dispensing mechanisms according to the invention: Fig. 2 shows a perspective cut-away view of a portion of the seed drill of Fig. 1 , this portion being shown on a larger scale than in Fig. 1, the drawing showing the relationship of the dispensing mechanisms to the structure of the drill and its hopper in particular; and Fig. 3 shows a perspective view of a dispensing roller forming part of the dispensing mechanisms of the seed drill of Figs. 1 and 2.

As shown in Fig. 1 a seed drill 10 comprises a frame 12 mounted on ground wheels 14 and having a draw bar 1 6 whereby the drill can be pulled by an agricultural tractor (not shown).

Seed drill 10 further comprises a hopper 1 8 mounted on frame 12, a series of furrow opening mechanisms in the form of coulters 20, a coulter operating mechanism 22 comprising hydraulic rams 24 for raising and lowering the coulters into and out of working engagement with the soil, and a series of dispensing mechanisms 26 provided one for each coulter 20, to dispense seed from hopper 18 for delivery to the furrows opened by the coulters. A series of seed delivery tubes 28 is provided to carry seeds from dispensing mechanism 26 to coulters 20.

A second series of dispensing mechanisms, identical to mechanisms 26, is provided on the rear side of hopper 18 to dispense fertiliser from the hopper to the furrows opened by coulters 20.

Dispensing mechanisms 26, and the second set of such dispensing mechanisms, are driven from ground wheels 14 by a drive train including ratiochanging gear boxes 30 and 32.

Fig. 2 shows part of the hopper 18 and four of the dispensing mechanisms 26, on a larger scale.

The hopper has a sloping front wall 34, a sloping inner wall 36, and a partition 38 between the seed and the fertiliser compartments of the hopper. A trough or well 40 is formed between a vertical lower face 42 of inner wall 36, and front wall 34.

A series of rectangular openings 44, is formed in the flat base wall 6 of well 40, one opening for each dispensing mechanism 26.

A series of feed funnels 48 is provided, one funnel for each dispensing mechanism 26, to receive the dispensed material and conduct it into delivery tubes 28 for deposition in the furrows.

Funnels 48 are mounted on a vertical lower portion 50 of hopper front wall 34, one funnel below each mechanism 26.

Turning now to the details of the construction of dispensing mechanisms 26, each mechanism 26 comprises a dispensing roller 52 mounted for rotation about an axis 54 to cooperate with a dispensing member 56 to define a downwardly tapering nip 58 through which particulate material is dispensed during use.

Each dispensing member 56 is in the form of a fixed flat plate of transparent material such as glass bonded to the inside surface of the hopper wall portion 50, one plate over each of a series of rectangular windows 60 cut out from wall portion 50, one window for each dispensing mechanism 26.

The structure of dispensing rollers 52 is best seen in Fig. 3. As there shown, each roller 52 comprises a body of resilient material in the form of non-expanded polyurethane having bonded therein a central mandrel 53 whereby the roller is received on a common drive shaft (not shown) and secured and driven by removable grub screws (not shown). Formed on the outer surface of each dispensing roller 52 is a series of feed formations 62 of generally wedge-shaped cross-section, the feed formations being arranged with the thin end 64 of each formation being adjacent the thick end 66 of the next formation. The profile of each roller 52, as viewed in the direction of axis 54, is similar to the axial profile of a ratchet wheel.

The thick end 66 of each feed formation 62 provides an upstanding feed face 68 on the surface of the rolier. Feed face 68 extends outwards from the roller in a generally radial direction and the direction of rotation R of the roller in use is such that the feed face pushes material to be dispensed through the nip 58.

The outer, seed and fertiliser contacting surfaces of feed formations 62 are formed with ribs 70 and grooves 72 extending parallel to the axis 54 of rotation of the roller.

Two sets 74 and 76 of the feed formations 62 are provided on each roller 52, the formations 62 of one set 74 being circumferentially offset (around the circumference of roller 52) from the formations 62 of the other set 76. This provides more even dispensing of seeds throughout each rotation of the roller. The degree of offset is such that the feed faces 68 on set 74 are positioned centrally (as seen in the axial direction) between the feed faces 68 on set 76.

A central slow rate band 78 is formed on the surface of each roller 52 between the two sets 74 and 76 of feed formations. Band 78 is for dispensing materials such as small seeds (e.g.

kale) at a relatively slow rate.

Slow rate band 78 cooperates with a seed confinement manifold 80 having arcuate flanges 81 at its underside, between which slow rate band 78 is a sliding fit. Manifold 80 is bolted to a small seeds hopper 82 from which seeds pass through an inlet opening 83 to the nip between slow rate band 78 and dispensing plate 56. A slot 84 in a mounting plate 85 cooperates with a mounting bolt 86 whereby the manifold 80 is removably secured to hopper wall portion 50 with plate 85 held against the inside surface of the glass dispensing plate. A window 87 in plate 85 allows slow rate band 78 to contact the dispensing plate.

Manifold 80 is of course removable for dispensing conventional cereal seeds. One manifold 80 and its seed hopper 86 is provided for each opening 44 in base wall 46.

Slow rate band 78 is formed with a series of slow rate feed formations 88, each being of generally wedge-shaped cross-section, the depth of the feed formations 88 being less than that of the feed formations 62 on the remainder of the surface of each dispensing roller 52.

The depth of the feed formations 62 measured radially at each feed face 68 is approximately 6 mm whereas the depth of the feed formations 88 on slow rate band 78 measured at the same corresponding place is approximately 1.5 mm. In this embodiment the diameter of each dispensing roller 52, measured between the outermost point on two feed faces 68 lying on a common diameter, is 100 mm.

Each slow rate band feed formation 88 is of the same circumferential length as the corresponding feed formations 62 and is formed with small ribs and grooves 90 extending parallel to roller axis 54, in the region of its thick end, the thin end of the feed formation being smooth. Feed formations 88 are circumferentially offset by an equal distance both with respect to the feed formations 62 of set 74 and with respect to feed formations 62 of set 76.

Turning now to the internal structure of each dispensing roller 52, as shown in Fig. 3 each roller has formed therein a series of internal recesses 92 and 94, the recesses extending lengthwise parallel to the axis 54 of rotation of the roller, each recess being of substantially uniform circular crosssection along its length, and the recesses being distributed at substantially regular intervals around the axis 54. Recesses 92 are larger than recesses 94, and the two sets of recesses 92, 94 are arranged on respective outer and inner pitch circles 96 and 98, both pitch circles being co-axial with the roller. Inner recesses 94 are angularly offset about roller axis 54 from outer recesses 92.

Outer recesses 92 define an outer deflection band 100 which is deflectible inwards into the recesses 92 to accommodate large particles (such as broad beans) being dispensed.

It will be noted that one large recess 92 is provided for each of the main feed formation 62.

Due to the circumferential offset of feed formations 62 in the two sets of feed formations 74 and 76, the recesses 92 corresponding to each feed formation 62 are correspondingly equally circumferentially offset, and thus each recess 92 extends only halfway across the width of the dispensing roller. The rollers are manufactured by a moulding technique.

A further feature of the dispensing rollers 52 is that the above-mentioned maximum depth of the feed formations 62 (approximately 6 mm) is greater than the thickness of the deflection band 100, the thickness of band 100 being measured at locations lying on radii from the roller axis 54 passing through the axes of recesses 92, the latter thickness being two to three millimetres (the variation being due to the presence of ribs and grooves).

In use, dispensing rollers 52 are rotated in direction R by the drive from ground wheels 14 and feed faces 68 positively feed seed through nips 58. The resilience of the dispensing rollers ensures a very gentle dispensing action, the nonexpanded form of the polyurethane gives the rollers remarkable durability, the glass dispensing plate 56 permit the dispensing action to be observed from the driving seat of the tractor hauling the drill. It can thus be seen that rollers 52 provide the dispensing mechanism with all the advantages inherent in a resilient roller dispensing mechanism, but without relying on a purely frictional grip between the roller and the material being dispensed. Thus, the dispensing rate achieved with a roller 52 is substantially independent of the frictional characteristics existing between the roller and the material being dispensed.In short, the rate of dispensing for a given rate of roller rotation is the same from hour to hour, day to day, and indeed from season to season.

The circumferential offset of formations 62 between sets 74 and 76 renders even more uniform the dispensing action. The provision of slow rate band 78 enables the advantages outlined above to be achieved with small seeds which require the use of a seed bottle. Slow rate band 78 occupies only about one sixth of the width of the roller and therefore dispenses seed at about one sixth of the rate which would be achieved with the full roller width. Therefore, undesirably slow rates of rotation of the roller are not required.

Among modifications which could be made in the above embodiment are the modification of manifold 80 by the deletion of slotted mounting plate 85 so that arcuate flanges 81 themselves make contact with glass dispensing plates 56. A small stiffening plate is provided across the flanges and a simple screwdriver-operated clamping device secures the manifold to hopper base wall 46.

Claims

1. A dispensing roller suitable for use in an agricultural dispensing mechanism for dispensing agricultural particulate material in which the roller is to be rotatably mounted to cooperate with a dispensing member to define a nip through which particulate material is dispensed during use; wherein the dispensing roller comprises a body of resilient material having formed on its outer surface a series of feed formations of generally wedge-shaped cross-section, the feed formations being arranged with the thin end of each formation adjacent the thick end of the next formation.

2. An agricultural dispensing mechanism for dispensing agricultural particulate material comprisingt a dispensing roller; a dispensing member mounted to cooperate with the dispensing roller in defining a nip to which, in use, agricultural particulate material to be dispensed is supplied; said dispensing ro'ler being mounted for rotation by a drive and being effective when rotated to dispense particulate material through said nip; wherein the dispensing roller comprises a body of resilient material having formed on its outer surface a series of feed formations of generally wedge-shaped cross-section, the feed formations being arranged with the thin end of each formation adjacent the thick end of the next formation.

3. A mechanism according to claim 2 wherein the profile of said dispensing roller as viewed in the axial direction of the roller is similar to the axial profile of a ratchet wheel.

4. A mechanism according to any preceding claim wherein the thick end of each feed formation provides an upstanding feed face on the surface of the roller, the direction of rotation of the roller in use being such that the said feed face pushes material to be dispensed, through said nip.

5. A mechanism according to any one of claims 2 to 4 wherein said feed formations are formed with ribs and grooves.

6. A mechanism according to any one of claims 2 to 5 wherein the dispensing roller comprises two sets of said feed formations, the formations of one set being circumferentially offset from the formations of the other set.

7. A mechanism according to claim 6 wherein the dispensing roller is formed with a central slow rate band between said two sets of feed formations, for dispensing materials at a relatively slow rate.

8. A mechanism according to claim 7 wherein said central slow rate band is formed with a series of slow rate feed formations of generally wedgeshaped cross-section, the depth of the feed formations on the slow rate band being less than that of the feed formations on the remainder of the surface of the dispensing roller.

9. A mechanism according to claim 8 wherein the feed formations on the central slow rate band are each formed with ribs and grooves in the region of the thick end of the feed formation.

10. A mechanism according to any preceding claim wherein the feed formations on the slow rate band are circumferentially offset with respect to the feed formations on each side of the slow rate band.

11. A mechanism according to any one of claims 2 to 10 wherein said body of resilient material has formed therein a series of internal recesses, the recesses extending lengthwise parallel to the axis of rotation of the dispensing roller, each recess being of substantially uniform cross-section along its length, the recesses being distributed at substantially regular intervals around the axis of rotation of the dispensing roller.

12. A mechanism according to claim 11 wherein said recesses are circular in crosssectional shape and are arranged on at least two pitch circles both of said pitch circles being coaxial with the dispensing roller, and at least some of the recesses on one pitch circle being angularly offset about the axis of rotation of the dispensing roller from the recesses on the other pitch circle.

1 3. A mechanism according to claim 12 wherein the recesses in the radially outer pitch circle are of larger cross-sectional area than those on an inner pitch circle.

14. A mechanism according to claim 1 3 wherein said recesses are arranged so as to define an outer deflection band of the dispensing roller, said feed formations being formed in said deflection band, and said deflection band being deflectible inwards into said recesses to accommodate particles being dispensed.

15. A mechanism according to claim 14 wherein the recesses in the radially outer pitch circle are provided at the rate of one recess for each feed formation.

1 6. A mechanism according to claim 1 5 wherein the maximum depth of the feed formations measured in the radial direction of the roller is greater than the thickness of said deflection band at locations lying on radii from the roller axis passing through the axes of said recesses in the radially outer pitch circle.

17. A mechanism according to any one of claims 2 to 1 6 wherein said body of resilient material comprises non-expanded polyurethane.

18. A mechanism according to any one of claims 2 to 1 7 wherein said dispensing member which cooperates with the dispensing roller to define a nip comprises a fixed flat dispensing plate formed of transparent material such as glass.

1 9. An agricultural dispensing mechanism for dispensing agricultural particulate material substantially as described herein and illustrated in the accompanying drawings.

20. A mechanism according to claim 2 wherein said dispensing roller is substantially as described herein and as illustrated in Fig. 3 of the accompanying drawings.

21. An agricultural implement for delivering agricultural particulate materials to the ground, the implement comprising a mechanism according to any of claims 2 to 20.