GB2123264A

GB2123264A - Cultivating machine

Info

Publication number: GB2123264A
Application number: GB08315877A
Authority: GB
Inventors: Michael Dunn
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-06-09
Filing date: 1983-06-09
Publication date: 1984-02-01
Also published as: GB2123264B; GB8315877D0

Abstract

A cultivating machine has a row of cultivator blades (17) which may be rotary or reciprocating and which cooperate with a fixed comb (18) located behind the blades. The spacing of the tines (20) of the comb and their distance from the cultivator blades (17) are such that soil clods are retained by the comb against the blades to promote a breaking- up and crumbling by the blades, without crushing the clods against the ground and thereby compacting the soil. Each tine of the comb may be of varying width along its length. <IMAGE>

Description

SPECIFICATION Cultivating machine The present invention relates to mechanical cultivators in general, and in particular to a cultivating machine of the type which, in use, is driven or drawn over the soil to be cultivated and has a plurality of cultivator blades or tines which pass through the soil in either a rotary or reciprocating fashion to break it up into a tilth. When the word 'blades' is used in the present specification it will be understood to include tines.

In cultivating machines of the rotary cultivator type having blades rotatable on a horizontal rotor shaft the shaft is usually driven at a speed such that the blades move faster than the speed of advance of the machine so that the blades are driven continuously through the soil to break it up.

In cultivator machines of the power harrow type with blades carried by rotors which rotate or oscillate about vertical axes, the blades are normally arranged in pairs on either side of respective vertical shafts, the shafts being aligned in a row transverse the direction of movement of the machine. As the machine is drawn or driven forward the blades are rotated or oscillated about their vertical shafts to break up the soil. The breaking up of the soil is caused by the repeated impact of the blades on the clods ahead of the machine. The blades of any one rotor have little or no effect on the soil once the soil has passed behind the rotor axis. A freely pivoted shield may be provided and may rest under its own weight on the ground behind the rotor to smooth the soil surface.

In a horizontal axis machine, or rotary cultivator, that is, a machine having blades rotatable about a horizontal axis, a fixed shield can assist in breaking up the soil clods to a smaller size. Such a shield, which may take the form of a cowl or hood, may be arranged so that it can be lowered into a position in which some of the relatively large lumps are thrown by the rotor blades against the shield and break up upon impact with the shield.

Where it is desired to break up the soil to a finer tilth than can be achieved by such a cultivator machine in one pass the machine has to make more than one pass over the soil, but in view of the extra time and fuel involved, and the compaction of the soil by the wheels of the machine and its tractor, such further passes are clearly undesirable. Moreover, having broken lumps of soil away from the mass of ground with such a machine, the soil is loose and further breaking-up can only be effected by using the ground as an anvil 'backcloth', that is, by breaking the clods of soil against the ground. In practice what frequently happens is that large clods of earth are simply pushed into the loose soil, without being broken up.Furthermore, the additional expenditure of energy can simply result in the virtual pulverisation of the upper layers of soil, which in turn can cause 'capping' of the soil by a fine dust layer, preventing the proper absorption of water by capil lary action.

The present invention seeks to provide a machine which can crumble and break up soil to a fine and structured tilth in a single pass over the ground, but without using the ground as an anvil or 'backcloth'.

According to the present invention there is provided a cultivating machine of the type which, in use, is advanced over soil to be cultivated, the machine having a plurality of cultivator blades which, in use of the machine, pass through the soil in either a rotary or a reciprocating manner to break up the soil, in which a fixed comb is located behind the cultivator blades with respect to the direction of advance of the machine, the comb having tines which project downwardly below the surface of the soil and the spacing of the comb from the cultivator blades being such that, in use of the machine, soil clods tend to be retained by the comb against the cultivator blades to promote the crumbling and the breaking-up of the clods, and thereby produce a tilth of soil particles of a size dependent upon the size and position of the comb.In effect, the comb acts as an anvil or 'backcloth' against which the clods of soil are retained to be broken up.

The comb may comprise a number of fixed parallel tines projecting downwardly from a horizontal support, the free ends of the tines being located above the lowermost parts of the cultivator blades.

A predetermined grading of the soil particles can be effected by a suitable geometry of the tines of the comb. Thus the tines of the comb may increase in width towards their lower ends so that the gaps between adjacent tines converge downwardly; for example, the tines may be provided with fins of tapering width at their lower ends. With such an arrangement, soil particles of larger size will be mainly near the top and particles of smaller size mainly near the bottom of the cultivated soil layer.

In an alternative embodiment of the invention the tines of the comb may decrease in width towards their lower ends so that the gap between adjacent tines diverge downwardly. With this arrangement the soil particles of the cultivated layer will tend to be graded with the particles of smaller size near the top and the particles of larger size near the bottom of the layer.

The cultivator blades may be freely movable, that is, ground driven, or may be power driven. For example, the cultivator blades may be driven hyd raulically or may be driven from a tractor power take-off, to rotate or oscillate in use of the machine about a number of vertical axes or alternatively about a common horizontal axis. Alternatively, the cultivator blades may be spring-loaded or driven so as to reciprocate angularly about a horizontal axis or set of axes.

In the present context, the term "comb" includes a structure having a plurality of fixed tines depending from a fixed support, and other comb-like structures capable of blocking the passage of soil clods above a certain size, including screens or baffles having grooves or a rectangular or other grating meshes.

With rotary cultivator blades, the grating screen or comb is preferably curved to surround a part of the path followed by the cultivator blades. Preferably, a hood is provided which surrounds a further portion of the path for guiding the particles of soil which have not passed through the comb back to a forward position in advance of the path of the blades or tines whereby they can be further broken up as the machine advances.

A secondary comb may be provided upstream of the comb, the secondary comb having tines between which the cultivator blades pass and which are resiliently biased whereby they can be displaced to permit harder particles, such as stones, to pass without causing damage.

A cultivating machine formed as another embodiment of the present invention may also be provided with a crumbler component downstream of the cultivator blades. The crumbler component may comprise a rotor having a horizontal axis and a generally cylindrical grid or mesh surface. The rotor may be made up of a plurality of rotatable discs joined at their peripheries by generally axially extending bars or rods, usually following an extended helical course. Machines provided with such a crumbler roller may also have a second screen or comb located behind the crumbler roller with respect to the direction of movement of the machine.

This second screen or comb serves as a backcloth against which particles of earth can be crushed so as to be broken up to a size small enough to pass therethrough, particles which do not pass therethrough being guided forwardly over the top of the crumbler roller to be further broken up thereby.

In a further embodiment of the invention, the cultivating machine may combine both reciprocating and rotary blades or tines. This is particularly applicable to a harrow, in which the leading portion of the harrow carries a screen or comb comprising fixed tines which are located forwardly and/or rearwardly of reciprocating cultivator tines, and the trailing portion of the harrow carries a rotary cultivator with a forwardly and/or rearwardly-disposed curved screen or comb, as described above. The positions of the rotary and reciprocating cultivators may, if desired, be reversed.

The invention will now be further described, by way of example, with reference to the accompanying purely diagrammatic drawings, in which: Figure I is a longitudinal vertical sectional view of a cultivating machine according to a first embodi mentofthe invention taken on line I-I of Figure 2; Figure 2 is a partly cut away rear view of the machine shown in Figure 1, viewed in the direction ofthe arrow II therein; Figure 3 is a partial plan view of the machine shown in Figures 1 and 2; Figure 4 is a rear elevational view, in the direction of arrow II in Figure 1, of the fixed screen employed in the machine, showing different configurations and arrangements of the tines of the screen;; Figure 5 is a schematic side view illustrating the main components of a second embodiment of a cultivating machine according to the invention, and Figure 6 is a sectional side elevational view of a cultivating machine according to a third embodiment of the invention.

Throughout the drawings the same reference numerals are used to designate the same or corresponding component parts of the illustrated embodiments.

Figures 1 to 3 illustrate a mechanical cultivator or power harrow machine 10 according to the invention. The machine 10 comprises a support frame, generally indicated 11, having linkage attachment lugs 12, 13 for attachment to a conventional agricultural tractorthree-point linkage by means of which the machine can be drawn over the ground to be cultivated. A drive shaft 14 is connectible to the power take-off (PTO) shaft of the tractor, and drives a gearbox 15 the output shaft (not shown) of which drives a number of rotors 16 arranged with their axes vertical and spaced apart laterally across the width of the machine. Each rotor 16 has a number of cultivator blades 17 which, in use of the machine, are driven through the soil by the rotation of the rotor to break up the soil as the machine is drawn in the direction of arrow A.

At the rear of the support frame 11 there is mounted a fixed comb 18 comprising a rigid transverse bar 19 supporting a plurality of depending rigid parallel tines 20 attached to the support bar 19 by screw clamps 21, shown diagrammatically. The tines 20 project downwardly below the surface of the soil, their lower ends being at a level slightly higher than the lower ends of the cultivator blades 17, the individual tines 20 being adjustable in depth by releasing the screw clamps 21.

The distance between the cultivator rotors 16 and the comb 18 is preferably adjustable. The action of the comb 18, which will be described later, is critically dependent upon this distance, which should ideally be between 2.5 cm and 20 cm.

The tines 20 define a grid through which only particles of soil below a predetermined size can pass. The centrifugal effect of the rotor blades 17 causes soil clods to be thrown against the screen or comb 18, which tends to retain the clods while they are broken up further by the action of the cultivator blades 17. Any soil clods which are too large to pass between the tines 20 are retained by the tines 20 against the rotating cultivator blades 17, and crumbled by the action of the blades 17, and by the pushing of earth against the retained earth clods.

The action of the comb 18 may be seen as that of retaining clods of earth in the 'soil boil' which is created by the action of the rotating cultivator blades 17, so that the clods are broken up by 'earth against earth' impingement without using the earth itself as a 'backcloth' or anvil.

Downstream of the comb 18, with respect to the direction of advance A, the machine carries a crumbler component comprising a cylindrical rotor 22 having a horizontal axis extending transversely.

The crumbler rotor 22 has a shaft 23 which is journalled at opposite ends in support arms 24. The support arms 24 are hinged about a horizontal axis to the rear of the frame 11, and screw-adjustable links 25, spaced from the hinge attachments, by means of which the angular settings of the two support arms 24 may be adjusted relative to the machineframe 11 to raiseorlowerthecrumbler rotor 22.

The crumbler rotor 22, which is of known construction, comprises a plurality of circular discs joined at their peripheries by substantially axially extending rods or bars 26 which follow a generally helical course to ensure a substantially even force on the rotor bearings. As the crumbler rotor 22 rotates the bars 26 perform a further soil crumbling action as the rotor 22 passes over the ground. The height setting of the crumbler rotor 22 determines the height of the cultivator blades 17 relative to the ground and, therefore, the depth to which the soil is cultivated in use of the machine. The crumbler rotor 22 may be driven to rotate either at the same speed as the speed of advance of the machine or at a faster or slower speed than this, but in the illustrated embodiment the rotor 22 is free to roll over the ground as the machine advances.

A further row of tines (not shown) may be mounted at the front end of the machine, upstream of the cultivator rotors 16, for the purpose of loosening the soil ahead of the rotor tines 17 and enabling the machine to travel faster. These further tines may be rigid or spring-mounted, and relatively -staggered or in line with each other.

A further screen or comb (not shown) may be supported on the frame 11 behind the crumbler rotor 22 and acts in a similar manner to the comb 18 in allowing only the fine tilth to pass between the tines thereof.

The comb 18 is shown separately in Figure 4. The tines 20 comprise straight cylindrical rods which are attached to the support bar 19 by means of clamping screws 21 at predetermined intervals, according to the intended size of the soil particles to be passed by the comb 18. The clamping screws 21 enable individual tines 20 to be adjusted. For example, when working some ground, some of the tines 20 may be clamped to the bar 19 at different levels from the other tines, so that the lower ends of the tines 20 are of different levels.

The tines 20 may be perpendicular to the bar 19 so that they extend vertically downwardly, as shown, or they may be clamped to the bar 19 in positions inclined to the vertical, if it is desired to move earth laterally as the comb 18 is advanced.

In the embodiment illustrated in Figures 1 to 3 the tines 20 of the comb 18 are straight and are substantially parallel to the rearmost surfaces of the rotor blades 17 to maintain a constant distance therefrom over the vertical extent of said blades.

Where the culvitator blades are curved the tines 20 of the comb 18 should also be curved to match the curvature of the rearmost surfaces of the blades.

At their lower ends the tines 20 may be provided with flat triangular fins 27 coplanar with the longitudinal axes of the tines, the fins 27 may taper in width downwardly, as shown at the left hand end of Figure 4, or may taper in width upwardly, as shown at the right hand end of Figure 4, according to the desired vertical grading of the soil particles. The tines 20 may be clamped to the support bar 19 in different orientations about their longitudinal axes.Thus the tines 20 may be attachable to the support bar 19 in different orientations with their fins 27 projecting laterally, that is, perpendicular to the direction of advance A, as shown at 27A in Figure 3, or longitudinally, that is, parallel to the direction of advance A, as shown at 27B in Figure 3, or inclined at 45" to the direction of advance A, as shown at 27C in Figure 3.

When the fins 27 are in positions 27A and 27C the gaps between adjacent tines 20 taper in width vertically, while when the fins 27 are in the positions 27B the gaps between adjacent tines 20 are uniform throughout the vertical extent of the tines.

Figure 5 is a diagrammatic side view of a harrow according to another embodiment of the invention.

The same reference numerals are used to designate parts corresponding to those of the embodiment of Figures 1 to 3. The frame 11 carries adjacent the linkage attachment lugs 12, 13 a row of springmounted blades or tines 28 which engage the ground in a reciprocating manner in a direction parallel to the direction of advance A in operation of the machine. The frame 11 is adapted to be towed behind a tractorthree-point linkage in a known manner, and supports a crumbler rotor 22 at its rear end.

A fixed comb is attached to the frame 11, and comprises a transverse row of downwardlyprojecting tines 29 which are located immediately behind the row of spring-mounted reciprocating tines 28. The tines 29 have horizontal lower portions 30 which project forwardly between the tines 28.

As the harrow advances over the ground in use, the reciprocating tines 28 penetrate and break-up the soil, the tines 28 reciprocating by being restrained by the soil and then springing forwards as the resistance of their spring-mounting to further compression overcomes the resistance of the soil. Any larger clods of soil which are thrown up by this springing forwards are broken against the fixed tines 29 of the comb, or are retained for reworking by the reciprocating tines 28 on their next stroke.

The crumbler rotor 22 mounted at the rear of the frame 11 cooperates with a fixed comb or baffle screen 31 supported from the frame 11 beneath the rotor 22 and defining a throat with the latter. The comb or screen 31 comprises a grid of horizontal bars extending laterally, and extends forwardly and rearwardly of the axis of the crumbler rotor 22, the screen 31 being held in the 'soil boil' created by the reciprocating tines 28 as the harrow advances.

Afurther row of spring-mounted reciprocating tines 32 may be mounted immediately behind the crumbler rotor 22 to perform a clod-retaining and crumbling action similar to that performed by the fixed tines 29.

The comb or screen 31 may have a rear portion which curves upwardly above the level of the axis of the crumbler rotor 22, in which case the tines 32 may be dispensed with.

The comb or screen 31 may be replaced by fixed blades or baffles extending laterally and generally horizontally below the crumbler rotor 22.

Figure 6 shows, in diagrammatic sectional side elevation, a mechanical cultivator according to another embodiment of the present invention. The rotor 16 in this embodiment has a horizontal axis and is provided with a plurality of cultivator blades 17 which, in use of the machine, are driven through the soil to break it up as the machine is drawn over the soil in the direction of arrow A. Carried by the fixed support structure is a grading comb 18 comprising a rigid transverse support bar 19 from which depend a plurality of rigid parallel tines 20 which are arcuately curved to follow the path of the tips of the blades 17, and which are spaced to define a grid through which only small particles of soil can pass.

The centrifugal effect of the rotor blades 17 causes soil to be thrown against the comb 18, which therefore serves to break up the soil. Any particles which are too large to pass between the tines 20 are carried over by the rotor blades and deposited on the ground in advance of the machine, to be reworked as the machine is drawn over them again. Harder lumps of soil maythus pass through the machine several times before being broken up to a sufficiently fine tilth to pass through the tines 20 of the screen 18.

The depth to which the rotor blades 17 penetrate the soil can be controlled by adjustment of depth control wheels 21 which, like the rotor 16, may be driven from the gear-box 15 by a transmission shaft 22 and belt or chain-drive 23 from the PTO shaft of the tractor.

Claims

1. A cultivating machine of the type which, in use, is advanced over soil to be cultivated, the machine having a plurality of cultivator blades which, in use of the machine, pass through the soil in either a rotary or a reciprocating manner to break up the soil, in which a fixed comb is located behind the cultivator blades with respect to the direction of advance of the machine, the comb having tines which project downwardly below the surface of the soil and the spacing of the comb from the cultivator blades being such that, in use of the machine, soil clods tend to be retained by the comb against the cultivator blades to promote the crumbling and the breaking-up of the clods, and thereby produce a tilth of soil particles of a size dependent upon the size and position of the comb.

2. A cultivating machine as claimed in Claim 1, in which the comb comprises a number of fixed parallel tines projecting downwardly from a horizontal support, the free ends of the tines being located above the lowermost parts of the cultivator blades.

3. A cultivating machine as claimed in Claim 2, in which the tines of the comb increase in width towards their lower ends so that the gaps between adjacent tines converge downwardly.

4. A cultivating machine as claimed in Claim 2, in which the tines decrease in width towards their lower ends so that the gaps between adjacent tines diverge downwardly.

5. A cultivating machine according to any one of the preceding claims, including a crumbler component located downstream of the cultivator blades with respect to the direction of advance of the machine.

6. A cultivating machine as claimed in Claim 5, in which the crumbler component comprises a rotor having a horizontal axis and a generally cylindrical grid or mesh surface.

7. A cultivating machine as claimed in Claim 6, in which the comb has a surface defining a throat with the cylindrical surface of the crumbler rotor.

8. A cultivating machine of the type which, in use, is driven or drawn over the soil to be cultivated and has a plurality of cultivator blades which, in use pass through the soil in either a rotary or reciprocating fashion to break it up into a tilth, in which there is further provided a grading screen or comb of predetermined spacing size located adjacent the cultivator blades and so positioned that soil particles are crushed by the blades against the screen or comb, or are retained thereby for crushing by the blades, the screen or comb allowing particles below the predetermined size to pass therethrough while particles above the predetermined size are retained for further working by the cultivator blades.

9. A cultivating machine as claimed in Claim 8 in which the blades rotate about a respective vertical axis in use of the machine.

10. Acultivating machine as claimed in Claim 9, in which the blades rotate about a common horizontal axis in use of the machine.

11. A cultivating machine as claimed in Claim 8, in which the grading screen or comb is curved to surround a part of the path followed by the blades and there is a hood which surrounds a further portion of the path for guiding particles of soil which have not passed through the screen or comb back to the forward part of the path of the blades to be further broken up thereby.

12. A cultivating machine as claimed in Claim 7, in which there is further provided a secondary comb at the junction between the primary screen or comb and the hood, the secondary comb having tines between which the blades of the rotor pass and which are resiliently biased whereby they can be displaced to permit harder particles such as stones to pass without being damaged thereby.

13. A cultivating machine as claimed in any one of Claims 8 to 12, in which a crumbler roller is located behind the cultivator blades with respect to the direction of advance of the machine.

14. Acultivating machine as claimed in Claim 13, including a second screen or comb located behind the crumbler roller with respect to the direction of advance of the machine and serving to guide particles which do not pass therethrough forwardly over the top of the crumbler roller to be further broken up thereby.

15. A cultivating machine substantially as hereinbefore described with reference to, and as shown in Figures 1 to 4, Figure 5 or Figure 6 of the accompanying drawings.