GB2187623A - Soil cultivating implement with adjustable screen - Google Patents

Abstract

A soil cultivating implement comprising a row of power-driven rotary soil working members 7 that extends substantially horizontally perpendicular to the intended direction of operative travel A of the implement has a spring-loaded 36 screen 28, 29 which protects upper tine-carriers 8 of the members 7 by deflecting stones met with during travel in the direction A. The carrier 28, 29 is upwardly and downwardly adjustable, in position, to suit operating conditions, using levers 24 turnable about pivots 23 located above a hollow frame portion 5 of the implement. The levers 24 are pivotted at 26 to arms 27 and can be turned to raise or lower the screen 28, 29 via those arms 27, the latter carrying brackets 30 which slide against stop brackets 31 mounted at the front of the frame portion 5. In an alternative construction (Figure 6), the stop brackets carry rollers (42) to co-operate with the brackets on the arms 27. In both embodiments, locking pins 33 co-operate with chosen holes 34 to maintain the levers 24 at appropriate angular positions about their pivots 23. <IMAGE>

Description

SPECIFICATION Soil cultivating implements This invention relates to soil cultivating implements or machines ofthe kind which comprise a plurality of soil working membersthataresupported byanel- ongate hollow frame portion, extending substanti allyhorizontallyperpendicular,oratleasttrans- verse, to the intended direction of operative travel of the implementormachine, so asto be rotatable about corresponding substantially vertical, or at least upwardly extending, axes, the hollowframe portion being connected to a frame memberthat is provided with a three-point coupling constructed and arranged for connection to the three-point lifting device or hitch of a tractor or other vehicle, the frame member having opposite ends that are located between the opposite ends of said hollow frame portion when the implement or machine is viewed in front or rear elevation, and each soil working member including a carrierfor at least one soil working tool, there being a screen located in front of said carriers with respect to the intended direction of op erative travel ofthe implement or machine and at substantially the same horizontal level as those carriers, the screen extending substantially horizontally perpendicular, or at least transverse, to said direction of operative travel and being upwardly and downwardly adjustable in position relative to other parts ofthe implement or machine.The expression "implement(s) or machine(s)" is replaced by "implement(s)" alonethroughouttheremainderofthis documentforthesake of brevity.

With known constructions ofthe kind setforth above, at least two connections have to be loosened to move the screen and after the adjustment, be retightened. It is therefore an object ofthe invention to facilitate the adjustability of the screen. In accordancewith the invention there is provided a soil cultivating implement ofthe kind set forth, wherein said screen is upwardly and downwardly adjustable in position relative to the carriers by the operation of at least one lever, the or each lever being pivotable about an axis which is located above the hollow frame portion between at least two different positions, means being provided to retain the or each lever in any chosen one of those positions.

For a better understanding ofthe invention, and to show how the same may be carried into effect, reference will now be made, bywayofexample,tothe accompanying drawings, in which Figure 1 is a plan view ofa soil cultivating implement in accordancewith the invention in the form of a rotary harrowthat is intended principally, but not exclusively, forthe preparation of seed beds.

Figure2is a side elevation, to an enlarged scale, as seen in the direction indicated by an arrow II in Figure 1, Figure3isa section,to an enlarged scale,taken on the line Ill-Ill in Figure 1, Figures a section, to an enlarged scale, taken on the line IV-IV in Figure 1, Figure 5is a rearview, to an enlarged scale, of lower substantially central rear parts of the implement as seen in the direction indicated by an arrowV in Figure 2, and Figure6isasideelevation,toan enlarged scale, illustrating an alternative construction and arrangement of parts that can be seen best in Figure 4 of the drawings.

Referring to the accompanying drawings and firstly to Figures 1 to 5 thereof, the soil cultivating implementthat is illustrated is intheform ofa rotary harrow which is intended primarily, but not necessarily exclusively, for preparing seed beds in pre- viouslyworked agricultural land.The implement has a carrying frame which is constructed and arranged for connection to the three-point lifting device or hitch of an ag ricu Itura I tractor o r other moving and operating vehicle in a mannerthatwill befurther described below, said carrying frame being afforded principally by a single frame beam 1 that extends substantially horizontallytransverse and usually, as illustrated, substantially horizontally perpendicular, to the intended direction oroperativetravel orthe implement that is indicated in several Figures ofthe drawings by an arrow A.It can be seen in Figure 3 of the drawings that the frame beam 1 isofhollowfor- mation having an oblong, rectangularcross-section and being so disposed that the longer parallel sides of the rectangle are substantially vertical whilstthe shorter parallel sides thereof are substantially horizontally parallel to one another and to the direction A (as seen in the cross-sectional view of Figure 3).

Plates 2 whose compound shapes can be seen best in Figure 2 and 3 of the drawings are rigidly secured to the opposite ends of the frame beam 1 so as to be substantially vertically parallel to one another and to the direction A. It can be seen in Figures 2 and 3 ofthe drawings that the plates are very approximately Zshaped, each plate 2 including a substantiallyvertically disposed upward projection 3 that is located principally rearwards ofthe frame beam 1 with re specttothe intended direction of operativetravel A.

The two upward projections 3form parts of corresponding substantially symmetrically identical parallelogram linkages 4 that will be further described below, these linkages 4 connecting an elongate hollow frame portion 5to the frame beam 1 in such a way that said frame portion Scan move upwardly and downwardly without significant tilting relative to said frame beam.

The hollow frame portion 5 extends substantially horizontally parallel to the frame beam 1 at a location behind the latter with respect to the direction A and it will be seen form Figure 1 ofthedrawingsthatthe two parallelogram linkages4 by which said frame portionS is coupled to the frame beam 1 are located approximately, although not exactly, one quarter of the way along the length of the frame portion 5 from corresponding opposite ends thereof. When the implement is viewed from the rear in the direction A, the hollowframe portion 5 projects by substantially equal distances beyond the opposite ends ofthe frame beam 1 and is located atsubstantiallythe same horizontal level as the latter, the precise relationship between the levels of the beam 1 and frame portion 5 being dependent upon the an gularityofthetwo linkages4atanytime.

Figures 3 and 4 ofthe drawings showthatthe hollow frame portion 5 is of trapezoidal cross-section comprising a lowerchannel-shaped part whose limbs are upwardlydivergentand an upperclosure plate that is parallel to the flat bottom of the lower part and that is firmly but releaseably secured to front and rear horizontal rims ofthe latter by a plurality of substantiallyvertically disposed bolts, a gasket being sandwiched between the edges ofthe closure plate and the uppersurfaces of said rims. The verti cal height of the hollow frame portion S is substanti- ally, although not exactly, equal to the fore-and-aft width of its bottom and this gives said hollowframe portion 5 a high structural rigidity.

A plurality, ofwhich there are sixteen in the example that is being described, ofsubstantiallyverti- cal, or at least upwardly extending, shafts 6 are rotat ablyjournalled in upperand lower ball bearings (see Figure 3) carried by the hollow frame portion 5 so as to lie in a single row with their longitudinal axes/axes of rotation parallel to one another and advantageously, but not essentially, spaced apart from one another at regular intervals of substantially 25 cent imetres.The single row of rotaryshafts 6 is, of course, parallel to the transverse length of the hollow frame portion 5 and each shaft 6 has a lower portion which projects downwardlyfrom beneath the bottom ofthatframe portion Sto carry a corresponding soil working memberthat is generally indicated bythe reference 7.Each soil working member7 has a central internallysplined hub that co-operates with matching external splines on the lower portion ofthe corresponding shaft 6, said hub being firmly but re leaseably secu red to that lower shaft portion by known meanswhich includes a washerand a nut furnished with a split pin or some other unit des- igned to prevent the nutfrom working loose. The nut co-operates with a short lowermost screw-th readed extremity of the corresponding shaft 6. The hub of each soil working member 7 forms the central part of a carrier8 ofthatframe portion which carriercomprises two arms that project outwardly and downwardlyform the hub at opposite sides of the latter.

The outer end of each carrier arm is integrally or rigidly provided with a corresponding sleeve-like tiner holder in which an upperfastening portion of a corresponding rigid metallic soil working tool in the form of a tine 9 is firmly but releaseably secured with the aid of a nut that cooperates with a screw-thread atthe upper end ofthe fastening portion which pro jects a shortdistance above a mouth atthotopofthe sleeve-like holder concerned. Each tine 9 has a downwardlytapering soil working portion which penetrates into the ground to an adjustable extent when the implement is in use as shown in Figures 2 and 3 ofthe drawings.

At locations which are between the third and fourth soil working members 7 counting from either end ofthe hollowframe portion 5, the top of said frame portion 5 hasthe base edge of an uprightsubstantially isosceles triangular plate 10 firmly but releaseably secured to it with the aid of corresponding pairs offrontand rearfeet 11 and 12, which feetaro welded to the plates 10 whose general planes are substantially vertically parallel to one another and to the direction A. It will be seen from Figure 3 of the drawings that the plates 10 afford rear portions, with respectto the direction A, ofthetwo parallelogram linkages 4, the base edge of each plate 10 extending throughout substantially the whole ofthe fore-andaft with ofthetop ofthe hollow frame portion 5.

Some of the same bolts as are employed to secure the closure plate ofthe hol low fra me portion 5 to the lower part thereof also serve to fasten the front and rearfeet 11 and 12 ofthe plates 1 Oto the top of said frame portion 5 and itwill be noted from the drawings that the front feet 11 are of greater extent in thedirectionAthan arethe rearfeet 12.

Four substantially horizontailly disposed pivot bolts 13turnablyconnectthe leading and rear ends of upper pairs of links 1 4to the two upward projections 3 and to the two triangular plates 10, and, similarly,further pivot bolts 13turnably connectthe opposite ends of lower pairs of links 15 to the same parts at a level spaced beneath that of the upper links 14. The upper and lower pairs of links 14 and 15 are, of course, parts of the corresponding parallelogram linkages 4.

Astop plate 16 is welded or otherwise rigidly secured to the leading upwardly inclined edge of each plate 10 at a location which is a short distance above the midpoint of that edge, each stop plate 16 being so disposed that it will prevent the hollow frame portion 5from moving downwardly, relative to the frame beam 1, beyond substantially the position that is shown in Figure 3 ofthe drawings in which the lower edge of the illustrated stop plate 16 bears againstthe upper edges of the corresponding pair of lower links 15. The lower pairs of links 15 are of stronger formation than are the upper pairs of links 14 and it will be noted that each pair of lower links 15 is formed with aligned holes 7 (Figure 3) which holes will register with a single hole formed through the corresponding intervening plate 10.When a horizontal locking pin is entered through the holes 17 and the hole in the intervening plate 10, the parallelogram linkage 4 concerned is rendered ineffect ive and the hollow frame portion Swill then occupy a fixed position with respect to the frame beam 1. The locking pins in question are not shown in Figure3 of the drawings but a careful inspection of Figure 1 thereof will show the oblique handles of the two removable locking pins installed in their operative positions.Itwill be noted from Figure3 ofthedrawings thattheupperand lowerpivotbolts 13 which are at the rear ends ofthe upper and lower links 14 and 15 of each parallelogram linkage 4 have theirsubstantially horizontal longitudinal axes contained in, or located very close indeed to, a substantiallyvertical plane which also contains the longitudinal axes/axes of rotation of all of the rotary shafts 6. This arrangement enables forces resisting continued progress in the direction A of the revolving soil working mem- bers7to be resisted in a particularly advantageous manner which is such that bending and breakage is very considerably reduced, if not entirely eliminated.

The opposite ends of the hol low frame portion 5 are closed by corresponding strengthening side plates 18 of oblong configuration (Figure 2) which side plates 18 extend substantially vertically parallel to one another and to the direction A. Shield plates 19 whose symmetrically identical shapes can be seen best in Figure 2 ofthe drawings are also prov ided adjacent the opposite ends of the frame portion 5 and actually just beyond the opposite ends ofthe single row of rotary soil working members 7.Each shield plate 19 cooperates with the immediately neighbouring rotary soil working member7 in work- ing the soil to the samethorough extent as is prod uced by co-operation between neighbouring soil working members 7 at locations closer to the centre ofthe implement. However, in addition,theshield plates 19 prevent the rapidly moving tines 9 from flinging stones and other hard objects laterally of the path of the implement so that damage and injury which mightotherwise be caused inthiswayissub stantially eliminated.The lower edges ofthe shield plates 19areshapedtoslideforwardlyoverthe ground surface in the direction A and each shield plate 19 is carried by a corresponding arm 20 that includes a portion which is mounted on top ofthe hollow frame portion 5 so asto beturnable about a corresponding substantially horizontal axis that is parallel or substantially parallel to the direction A.

This allows the shield plates 19to move upwardly and downwardly to match undulations in the surface ofthe ground that may be met with during operative progress in the direction A and also enables each shield plate 19to beturned upwardly and inwardly about the axis concerned through substantially 1800 to reach an inoperative transport position in which it is inverted on top ofthe hollow frame portion 1.

The front of the hollowframeportion 5, with re spect to the direction A, is provided at two locations which are mid-way between the second and third soil working members 7, counting from the opposite ends of the single row of such members 7, with cor responding pairs of upright support strips 21 whose upper oblique edges are rigidly interconnected by horizontally extending tie strips 22 (Figuresi and 4).

Thetie strips 22 are atthe leading endsofthedown- wardly and rewardly inclined upper edges ofthetwo parallel but horizontally spaced apart support strips 21 of each pair and each such pair carries, towards the upper ends thereof, a respective pivot bolt 23 that is substantially horizontally parallel to theframe beam 1 and hollow frame portion 5.A lever 24 is turnably mounted on each pivot bolt 23 between the corresponding pair of support strips 21.The leading end of each lever 24, with respect to the direction A, projects a short distance in front of the respective support strips 21 alongside a much shorter strip 25 that projects substantially only forwa rdly from the pivot bolt 23 concerned in horizontally spaced apart relationship with the leading end of the lover 24 under consideration, a spacing sleeve being prov ided on the pivot bolt 23 to produce this spaced re lationship.The leading end of each lever 24 and the neighbouring shorter strip 25 projectforwardly in fork-like relationship and have the upper end of a corresponding substantially vertical carrying arm 27 pivotally mounted between them with the aid of a corresponding horizontal pivot pin 26 defining an axis that is substantially parallel to that of the aligned pivot bolts 23 and the longitudinal axis ofthe hollow frame portion 5.

Afurther pair of upright support strips 21 have a further carrying arm 27 pivotally connected to them in the same way at a location which is spaced a short distance to one side of the centre of the transverse length ofthe hollow frame portion 5 but, at thins location, there is no lever 24 nor shorter strips 25. The lower ends ofthethree carrying arms 27 are all secured to a screen 28 that extends substantially hori zontally parallel tothe hollowframe portion 5 ata location immediately in advance of the rotary soil working members 7, with respect to the direction A, and at substantiallythe horizontal level of the carriers 8 of those members 7.The screen 28 extends throughout substantiallythe whole of the combined working width ofthe sixteen soil working members 7 that are provided in the example which is being des cribed.Thescreen 28 (Figure 4) takes the forum of a beam that is channel-shaped in cross-section, said channel having a flat substantiallyvertically disposed bottom from the opposite edges of which two limbs diverge steeply upwardly and rearwardly and downwardly and rearwardly, respectively, the lower limb being longer (as seen in cross-section) than the upper limb. The two limbs are strengtheningly interconnected towards their rear edges by a plate 29 that is substantially vertically parallel to the bottom of the channel portion of the screen 28. This formation of the screen 28 gives it a high degree of rigidity.A bracket 30 (Figure 4) is provided on each carrying arm 27 and the screen 28 at a location which is principally behind the arm 27 concerned with respectto the direction A. Each bracket 30 includes an upright portion 30A and a portion which extends substantially horizontally forwards from the portion 30Ato be secured to a corresponding one ofthe carrying arms 27. The upright portion 30A of each bracket 30 normaily bears rearwardly against a forwardly directed upright limb 32 of a stop bracket31 that is fastened to the front of the hollow frame portion Satan appropriate position therealong by means which includes the bolts that secure the upper closure plate of the hollow frame portion 5to the lower partthereof.

Beneath its upright limb 32, each stop bracket 31 is bent over roarwardlyto form a portion in perpendicular relationship with the upwardly and forwardlyinclinedfrontwall ofthe lower part of said frame portion 5. The upright limb 32 of each stop bracket 31 has a considerably greatorvertical extent that does the upright portion 30Aofthe bracket 30 which bears against it and this arrangement allows such bearing contact to be maintained whiistthe carrying arms 27 are displaced upwardly or downwardly using the levers 24.

As can be seen bestin Figure 4 of the drawings, each outer pair of upright support strips 21 (but not the substantially central pair thereof) is formed with upper and lower pairs ofaligned holes 34 and the corresponding lever 24 and shorter strip 25 is formed with holes that can register with either set of holes 34 depending upon the angular position of said lever 24 and shorter strip 25 about the axis defined by the pivot bolts 23. A horizontal locking pin 33 is provided forentrythroughthe holes in each lever24andthe corresponding strip 25 and either the upper pair of holes340rthelowerpairofholes34inthecor- responding pair of support strips 21.Thus,the screen 28 can be retained in either the lowered position illustrated in Figure 4 ofthe drawings or an alternative raised position. In the illustrated lowered position, the lower edges ofthe levers 24 and strips 25 bear against stop strips 35 which interconnectthe two supportstrips 21 of each outer pair whereas, in the alternative raised position, the upper edges of the levers 24 and shorter strips 25 bear againstthe lower surfaces of the tie strips 22 which tie strips thus also afford a "stop" function. Further holes may be provided to define at least one other "intermediate" position ofthe screen 28.

Each carrying arm 27 is formed, ata location a short distance above its mid-point, with a hole into which the leading end of a corresponding helical tension spring 36 is hooked. Each tension spring 36 extends substantially horizontally rearwards from the corresponding carrying arm 27 to have its rear end hooked into an eye 37 which eye is coupled adjustably to a corresponding bracket 38 bolted to the top and rearofthe hollow frame portion 5.Each eye 37 has a screw-threaded shankwhich is entered through a hole in an upright portion of the cor- responding bracket 38, said shank being provided at the side of that bracket portion which is remotefrom the corresponding spring 36 with a pair of nuts 39 which are adjustable lengthwise of said shankto increase or decrease the initial tension of the spring 36 concerned whilst being arranged to act normally in the well known manner of lock nuts. The pressure by which the brackets 30 normally bear rearwardly against the stop brackets 31 can be increased or decreased by increasing or relaxing the initial tension in the springs 36.Eitherthe raised or the lowered position ofthe screen 28 may be adopted by the user of the implement having regard to the nature and condition of the soil that is to be dealt with and with a viewto said screen 28 engaging stones and other hard objects and deflecting them downwardly into the soil to avoid damage to the carriers 8 of the soil working members 7 and the upper fastening portions of the tines 9. In addition, the screen 28, and par ticularly its plate 29, will co-operatewiththe rotating members 7 in crumbling the soil and will thus augmentthe crumbling action that is produced by cooperation between immediately neighbouring soil working members 7 themselves.Should a large stone or other hard object become momentarily jammed between at least one ofthe soil working members 7 and the rear ofthe screen 28, that screen 28 can deflectforwardlyto allow release ofthe stone or other hard object, without damage, byturning aboutthe axis defined by the pivot pins 26 against the adjustable restoring action of at leastone ofthe tension springs 36. The readydeflectabilityofthe screen 28, againstthe restoring action of the springs 36, is important to the efficient functioning of the implement having regard to the factthat said screen 28 extends, as a single unit, throughout substantially the whole ofthe rolativelygreatworkingwidth ofthe implement.

Figure 6 ofthe drawings illustrates an alternative construction to thatwhich has been described with particular reference to Figure 4, those parts that are illustrated in Figure 6 butwhich are similar or ident- ical to parts that have already been described with reference to Figure 4 being indicated in Figure 6 by the same references as are used in Figure 4 so that a repeated description thereof is rendered unnecessary. In the embodiment of Figure 6, the brackets 30 and co-operating stop brackets 31 are no longer employed.The front of the lower part of the hollow frame portion 5 is, instead, provided with a match ingly shaped bracket 41 at each ofthe locations which registers, in the direction A, with one ofthe carrying arms 27, each bracket 41 being releaseably secured in its appointed position by some of the bolts that fasten the top closure plate of the frame portion 5 to its lower part. Each bracket 41 carries an obliquely forwardly directed fork between the limbs of which an axle pin 42 is mounted so asto extend substantially horizontally parallel to the transverse length of the frame portion 5.Each axle pin 42 has a corresponding roller mounted thereon in a freely rotatable manner between the limbs of the corresponding fork and the front of each roller 40, with respect to the direction A, bears against a track strip 43 which is welded or otherwise rigidly secured to the rear edge ofthe carrying arm 27 concerned in perpendicular relationship with the general plane of that carrying arm 27.The upper end of each track strip 43 is bent over perpendicularly rearwardlyfrom the corresponding carrying arm 27 to lie between the two supporting strips 21 ofthe corresponding pair so that, when the levers 24 are used to move the screen 28 upwardly or downwardly, the bent over ends of the track strips 43 move between the supporting strips 21 in the manner of guides or stops thatpre ventthe screen 28 from being displaced to any sign ificantextentin a lateral direction parallel to its own transverse length. The springs 36 act normally to maintain the track strips 43 firmly in contact with the rollers 40 but, as described above, forward deflection ofthe screen 28 is possible, against the restoring action ofthe springs 36 to release a momentarily jammed large stone or other hard object.

Lugs44 projectforwardly and upwardlyfromthe frame beam 1 at locations spaced by short distances from the opposite ends of the latter, the flat lugs being substantially vertically parallel to one another, to the direction A and to the plates 2, each lug 44 being spaced by only a relatively short distance from a corresponding one of those plates 2. The leading downwardly inclined end of an arm 47 isturnably mounted between each lug 44andthe neighbouring plate 2 with the aid of a respective strong horizontal pivot 45 and a sleeve 46 which surrounds that pivot 45 in such a way that the arm 47 concerned lies alongside the lug 44 rather than the neighbouring arm 2. The two arms 47 extend generally rearwardly from the lugs 44 and arms 2 and a further pairofsim ilar iugs 44 are mounted on the frame beam 1 ata short distance to one side of the midpoint ofthat frame beam, these further two lugs 44 having the leading end of a third arm 47 turnably mounted between them by a strong pivot that is in aligned relationship with the strong pivots 45. When the implement is viewed from the rear in the direction A, the pair of lugs 44that hasjust been mentioned is located a short distance to the right of the mid-point of the frame beam 1.

The three arms 47 all extend generally rearwardly overthe hollow frame portion 5from the pivotally mounted obliquely downwardly'and forwardly inclined leading ends thereof. Each arm 47 comprises a straight and more or less horizontal portion that is of progressively increasing vertical width from front to rear, this portion integrallyterminating in a downwardly and rearwardly inclined portion. Thus, as seen in side elevation (Figure 2) each arm 47 is of shallow arched formation which leaves sufficient room beneath the central straight and more or less horizontally disposed portion thereofforthe hollow frame portion 5 to move upwardly and downwardly relative to the frame beam 1 withoutfoulingsaid arms 47.

The rearmost extremity of each arm 47 is firmly but releaseably secu red by four bolts 48 to a leading region of a corresponding plate 49. The central plate 49 is a little different in shape as compared with the outer plates 49 but the three plates 49 are substantially vertically parallel to one another and to the direction A, each of them being welded or otherwise rigidly secured to both an upper beam 50 and a lower beam 51 The upper beam 50 lies vertically abovethe lower beam 51 ,said beams 50 and 51 both extending throughout the length ofthe hollow frame portion 5 in substantially perpendicular, or at least transverse, relationship with the direction A.

The lower beam 51 is both substantially straight and substantially horizontal whereas the upper beam 50 is of inverted very shallow V-shaped con figuration, said beam 50 thus comprising two straight limbs which diverge outwardly and down wardly from the mid-point of the beam (see Figure 5) in such a way that the distance between the two beams 50 and 51 at the ends thereof where they are interconnected by substantially vertical plates 52 (Figure 2) is significantly less than is the distance between them at their mid-points (Figure 5). Stay plates 53 strengtheningly interconnect the upper and lower beams 50 and 51 at intervals along the lengths thereof.The arms 47, beams 50 and 51 and associated parts afford a carrying assemblyfortwo axially aligned ground rollers 54 which, in the example that is being described, are both in the form of so-called "packer" rollers, the neighbouring ends of the two rollers 54 being closely adjacent to one another.

The mid-points ofthe upper and lower beams 50 and 51 are interconnected by a plate 55 which extends generally downwardly and forwardly from those beams with respect to the direction A in sub stantiallyverticallyparallel relationshipwiththatdir- ection A. The lower leading end of the plate 55 has a support 56 of inverted U-shaped formation rigidly secured to it in such a way that the limbs ofthesup- port extend downwards in corresponding vertical planes from the curved base thereof whose convex surface is fastened to the plate 55. The two limbs of the support 56 areformed with aligned bearing holes in which corresponding stub shafts 57 at the neighbouring axial ends of the two rollers 54 are freely rotatably received with some clearance.The holes in the limbs ofthe support 56thusfunction as plain rotary bearings but could be provided with ball bearings orthe like. The two stub shafts 57 are mounted on plates carried at the corresponding ends of hollow cylinders 58, of circuiarcross-section, whose outer surfaces are the curved surfaces of the rollers 54that will bearaainstthe ground when the implement is in use. The opposite outer ends ofthe two rollers 54 are provided with bearing housings 59 (Figure 2) which housings 59 carry horizontal ball or other bearings which receive corresponding stub shafts 60 that are fastened to downwardly and forwardly inclined support plates 61 which are secured, in turn, to the plates 52 interconnecting the ends of the upper and lower beams 50 and 51 by groups of four bolts 62.

The outer surface of the cylinder 58 of each ground roller54 is provided with a plurality of groups or crowns of flat tine-like teeth 63, each group or crown being contained in a corresponding plane that is substantiallyvertically parallel totheothergroups or crowns of the same roller 54 and to the direction A, the groups or crowns being spaced apart from one another at regular intervals along the axial length of each roller 54 (Figures 1 and 5). In the example which is being described, each group or crown of teeth 63 comprises ten of those teeth which are spaced apart from one another at regular 36 intervals around the longitudinal axis of the corresponding roller 54.

Scrapers 64 which are intended to prevent mud, clods of soil, root remnants and other crop debris from adhering to the rollers 54, and particularly from becoming jammed betweentheirgroupsorcrowns of teeth 63, are provided behind the rollers 54 with respect to the direction A at a level which is only a short distance above that ofthe ground surface (see Figure 2). The scrapers 64 are substantially oblong in shape and each ofthem has a leading edgewhich is located very closely adjacent to, but preferably not in actual contact with, the outer surface of the cylinder 58 of the corresponding roller 54 between two neighbouring groups or crowns of the teeth 63.The scrapers 64 are adjustably mounted on feet carried at the lower leading ends of downwardly and forwardly inclined carrier arms 65, the upper ends of these carrier arms 65 being secured by U-bolts 67 to plates 66 in groups offour, that is to say, each plate 66 has four arms 65 andthusfourscrapers 64fastened to itin such awaythatthecompletegroupcan be angularly adjusted about the longitudinal axis ofthe lower beam 51 to bring the four scrapers 64 of that group eithorcloserto, orfu rther away from, the outer curved surface of the associated roller cylinder 58.

Each plate 66 is of very shallow channel-shaped cross-section, the very short perpendicularly bent over limbs thereof being formed with concave recesses which match the convex curvature of the outer surface of the lower beam 51. To adjust each group of four scrapers 64, as a whole, relative to the corresponding roller cylinder 58, it is only necessary to loosen the nuts on the shanks of the correspond- ing four U-bolts 67 and to displace the group angularly in the required direction around the longitudinal axis of the lower beam 51.Re-tightening of the nuts will maintain the freshly adjusted position as long as may be required but, preferably, the nuts are nottightened to such an extent that a pointed stone or other object penetrating between one of the scrapers 64 and the surface of the corresponding cylinder 58 cannot deflect the corresponding group of four scrapers around the axis ofthe lower beam 51 againstthefrictional clamping action of the U-bolts 67 to prevent breakage or bending damage.

Horizontal bolts 46A (Figure 5) and surrounding spacing sleeves 68 secure the central one of the three arms 47 to a relatively parallel support plate 69 ata location towards the rearmost end of that arm 47, the support plate 69 being provided, at its front with respectto the direction A, with a horizontal pivot pin 70 (Figures 2 and 5) which connects the plate 69 to a fork at the outer end of the piston rod of a hydraulic piston and cylinder assembly 71 which extends obliquely upwardly and forwardly from the pivot pin 70 to carry, atthe upper leading end of its cylinder, a support 72 fora screw-threaded adjusting mechanism 73 comprising a manually operable crank handle at its upper leading end.The support 72 is turnably connected by a horizontal pivot pin 74to a bracket 75 which projects upwardly from the top of a horizontal beam 76 affording an upper part of a coupling member ortrestle 77 by which the frame beam 1 of the implement can be connected to a three-point lifting device or hitch mounted at the rear of an agricultural tractor of other vehicle which both moves the implement in the direction A and operates the moving parts thereof. The hydraulic piston and cylinder assembly 71 is provided with hydraulic connections (notshown)forcoupling itto the hydraulic system ofthe tractor or other vehicle which both moves and operates the implement.

The screw-threaded adjusting mechanism 73 acts, upon rotation of its screw-threaded spindle byturning the crank handle in an appropriate direction, to move a stop (not visible) either upwardly or downwardly inside the cylinder of the assembly 71, the adjustment being carried out to control the location to which the piston ofthat assembly 71 can move in the cylinder with this position corresponding to a chosen horizontal level of the ground rollers 54 relat iveto that oftheframe portion 5 and soil working members 7.Thus, an advantageous relative level which has been setfor a particular cultivating operation can quickly be re-established, after, purely four example, an over-night stoppage, merely by extending the assembly 71 hydraulically until the piston thereof meets the adjustable stop, no readjustment being necessary until a fresh job is to be undertaken under different conditions. It should be noted that it is the level of the ground rollers 54 relative to that of the frame portion 5 and soil working members7 which principally governs the maximum depth of penetration of the tines 9 ofthe soil working mem- bers7 into the soil which is possible.The opposite endsofthe beam 76 ofthe coupling memberor trestie 77 are connected tothe top oftheframe beam 1 by corresponding upright plates 78 (Figure 2) which plates are substantiallyvertically parallel to one another and to the direction A. The relatively remote sides of the two plates 78 are provided with strengthening supports 79 (Figure 2) whose lower ends are secured to the top of the frame beam 1.

Shaped lower leading portions of the plates 78 substantially match the shapes of parallel and closely neighbouring plates 80 (Figure 2) and each pairof plates 78/80 affords a lower coupling point of the three-point coupling member or trestle 77, the single central upper coupling point thereof being afforded by two parallel spaced apart plates 81 (Figures 1 and 2) which surround the upper horizontal beam 76 at a location substantially mid-way along the transverse length ofthat beam 76.Figures 1 and 2 ofthe drawings somewhat diagrammatically illustrate the way in which the free ends ofthe upper and lower lifting links ofthethree-point lifting device or hitch at the rear of a n an agricultural tractor or other operating and moving vehicle are turnably connected to the two lower coupling points and single upper coupling point which have just been discussed.

Afork 82 (Figure5) is provided a that side of the support plate 69 which is remote from the neighbouring and parallel central arm 47 and one end of an elongate lateral stabilizer 84 is turnably mounted between the limbs of the fork 82 by a pivot pin 83.

The stabiiizer 84, which is adjustable in length, is loosely and therefore universally movably connec- ted to the fork 82 by the pivot pin 83 and extends from thatfork 82 towards the right end of the implement when the latter is viewed from the rear in the direction A, the opposite end ofthe stabilizer 84 being loosely and therefore universally movably connected by a pivot pin 85to a forked bracket 86 mounted atthe rearofthe hollowframe portion 5 very close to the right end of that frame portion when the implement is again viewed in the direction which has just been mentioned.A second but much shorter stabilizer 87 which is again adjustable in length loosely interconnects a forked bracket 88 carried by the coupling member or trestle 77 adjacent the bottom thereof and a further forked bracket 89 atthe rearoftheframebeam 1,thesecondstabilizer87ex- tending to the left from the coupling member or trestle 77 when the implement is viewed from the rear in the direction Aand having a maximum length which is only approximately one third ofthat ofthe first-mentioned stabilizer 84.

Each shaft6 is provided, insidethe hollowframe portion 5, with a corresponding straight- orspur- toothed pinion 90, the size of each pinion 90 being such that its teeth are in mesh with those of the or each immediately neighbouring pinion 90 in the single row of sixteen, in this embodiment, such pinions. One ofthe centre pair of shafts 60 in the single row of sixteen shafts has an upward extension into a speed-reducing gearboxwhose rotary input shaft, in turn, extends into a gearbox 91. Shafts and bevel pinions inside the gearbox 91 indirectly place the upward extension ofthe shaft 6 mentioned above in driven connection with a rotary input shaft 93 ofthe gearbox 91 which shaft 93 projects substantially hor izontally forwardly from the front of the gearbox 91 and is splined or otherwise keyed to enable itto be placed in driven connection with the rear power takeoff shaft ofthetractor or other vehicle which is to move and operate the implement by way of an intermediate telescopic transmission shaft 94, which is of a construction that is known per se, having universal joints at its opposite ends. The roar of the gearbox 91, with respect to the direction A, is provided with a change-speed gear 92 whose construction is not illustrated in detail since it does not form the subject of the present invention.It suffices to say that two splined or otherwise keyed shafts projects into the chago-speedgear92andcarrya pair of meshing straight- orspur-toothed pinions whose sizes establ- ish a pre-determined transmission ratio between the two shafts concerned. The change-speed gear 92 has a readily removable cover and the pinions which have just been mentioned can be interchanged on the shafts, or be exchanged for another pair of cooperating pinions of different sizes, to changethe transmission ratio between the two shafts.Thus, the speed at which the soil working members7 will ail be rotated can be increased or decreased without having to alterthe speed of driving rotation that is applied to the rotary inputshaft 93 of the gearbox91 from the rear power take-off shaft of the operating tractororothervehicle. It will be seen from Figure 1 of the drawings that the shaft 93 which protrudes from the front of the gearbox 91 also protrudes from the rear ofthe change-speed 92 to enable itto be used as a source of rotary power for the moving parts of some other implement, machine ortool that may be coupled to the rear ofthe soil cultivating implement, for use in combination therewith, in a mannerwhich will be described below. Such implement, machine ortool might be, for example, a seed drill ora planting machine.

The tops ofthe two upright plates 78 ofthe coupling memberortrestle 77 have the leading ends of corresponding upper arms 95 turnably connected to them by aligned strong pivots 96 which define a substantially horizontal axis that is parallel orsubstantially parallel to the frame beam 1, said arms 95 extending more or less horizontally rearwardsfromthe pivots 96 to locations in rear regions of the implement. The same upright plates 78 also have the leading ends of corresponding lower arms 97 connected to them by horizontally aligned strong pivots 98 which define an axis that is parallel to the axis of turnability ofthe upper arms 95 which is defined by the aligned pivots 96.The pivots 98 are mounted in the upright plates 78 at locations spaced upwardly and rearwardlyfrom the top oftheframe beam 1 (see Figure 2). The arms 97 again extend more or less horizontally rearwardly from their pivots 98 for app- roximately the same distance as do the upper arms 95, the pair of upper arms 95 being rigidly and trans versely interconnected, towards their rearends, by a horizontal beam 99 of hollow formation and circular cross-section. Similarly, the pair of lower arms 97 is rigidly and transversely interconnected by a horizontal beam 100.However, in this case, the hollow beam 100 is of oblong (see Figure 2), or alternatively square, cross-section and interconnects the extreme rear ends of the two arms 97 rather than being spaced forwardly from these extreme rear ends as is the hollow beam 99 in relation to the upper pair of arms 95.

The rearmost ends of the two lower arms 97 are bevelled inwardly (Figure 1) and, at the locations of theirjunctions with the interconnecting hollow beam 100, have the upper leading ends of corresponding downwardlyand rearwardly inclined brackets 101 fastened to them. A coupling mechanism 104 is turn- ably connected by horizontally aligned pivots 102 to the rear ends of the upper arms 95 and by aligned parallel pivot bolts 1 03 to the lower rear ends of the brackets 101. The coupling mechanism 104 is of basically rectangular configuration including an upper horizontal beam 105 of angular, and preferably square, cross-section which extends substantially parallel to the frame beam 1.Two beams 106 ofthe same cross-sectional shape and size as the same beam 105 extend downwardlyand more or less rearwardly from the opposite ends of the beam 105 in parallel relationship with one another, the lower ends of the beams 106 being secured to bevelled plates and further relatively parallel portions ofthese plates being turnably connected to the respective, brackets 101 bythe pivot bolts 103.

Lugs 107 surround the opposite ends of the beam 105 and portions thereof project forwardly, with re spect to the direction A, and actually establish the pivotal connections, by way of the aligned pivots 102, to the rear ends ofthe upper arms 95 (see Figure 2). The plates at the lower ends of the beams 106, and the brackets 101, are turnably connected to the upper ends of rearwardly directed hooks 108 by the respective aligned pivot bolts 103 and these hooks 108 afford the two horizontally spaced apart lower coupling points of a three-point lifting device or hitch of the implement itselfwhich is afforded by the coupling mechanism 104.The single upper coupling point of this lifting device or hitch is afforded by a pair of substantially vertical Iy paral lel, but horizontal iy spa- ced apart, plates 109 which surround a central region of the beam 105 and project downwardly and forwardly therefrom (Figure 2), the downwardly and forwardly projecting portions being formed with horizontally aligned holes through which an upper coupling pin can be entered. The construction and arrangement ofthe three-point lifting device or hitch ofthe implement itself is such that a further implement, machine or tool which may be mounted behind the soil cultivating implement is located as close as possible to the latter thus facilitating a compact disposition of the complete combination.

The hollow beam 99 which transversely interconnects the upper pair of arms 95 towards their rea rm ost ends carriestwo forwardly projecting lugs 110 at locations spaced by equal short distances from its opposite ends. Each lug 110, and the corresponding upper arm 95, is formed with a relatively short axially extending slot 112 (Figure 2) and each such pair of slots has a horizontal pivot pin 111 entered horizontally therethrough in perpendicular relationship with the lengths ofthe arms 95 and lugs 110 and in such a way as to be movable lengthwise along the slots 112 concerned. Each pivot pin 111 is surrounded by a sleeve (see Figure 1) at the free end ofthe piston rod of a corresponding fluid pressureoperated piston and cylinder assembly 113, the leading lower end of the cylinder of each assembly 113 being turnably connected to a shoulder of the corresponding upright plate 78 by a strong horizontally disposed pivot 114. It will be noted that the axis defined bythetwo horizontally aligned strong pivots 114 is located at substantiallythe same horizontal level as is the bottom of the beam 76.

The pivots 96 by which the upper arms 95 are turnably connected to the upright plates 78 of the coupling member ortrestle 77 also have corresponding latches 115 turnably mounted on them, the latches 115 being located at the relatively remote or outer sides of the upright plates 78 and upper arms 95. The rear end of each latch 115, with respectto the direction A, is formed with a jaw whose shape can be seen in Figure 2 ofthe drawings and each such jaw is arranged to co-operate retainingly with a corresponding pin 116 that projects horizontallyfrom the outer side of the corresponding lower arm 97. As can be seen in Figure2 of the drawings, the pins 116 are mounted on the lower arms 97 at locations which are short distances to the rear ofthe midpoints of those arms.The latches 115 project short distances forwardly ofthe pivots 96 and these forwardly projecting portions are formed with holes 117 into which extend, with sufficient clearance to allow limited turning movements ofthe latches 115 aboutthe pivots 96, corresponding stop pins 118.Each latch 115 has the end of a cable or otherflexible but inextensible operating member 119 connected to it at a point spaced from the corresponding pivot 96, the members 119 extending to locations on the agricultural tractor or other vehicle that moves and operates the implement and these locations being readily accessible to the driver of that tractor or othervehicle so that, upon pulling them forwardly, the latches 115 will be raised to the extentthat is allowed by the cooperation between the holes 117 and stop pins 118 which is sufficientto disengage the latch jaws from the pins 116 on the lower arms 97.

In the use ofthe soil cultivating implement that has been described in preparing a seed bed, its coupling member ortrestle 77 is connected to the three-point lifting device or hitch at the rear of a tractor or other operating vehicle using the lower plates 88 and the upper plates 81 forthat purpose. The rotary input shaft 93 ofthe gearbox 91 is placed in driven connection with the rear power take-off s haft of the same tractor orothervehicle using the known telescopic transmission shaft94which has universal joints at its opposite ends.Adjustments which may, if required, be made before work commences include raising or lowering the bodily level ofthe two ground rollers 54 relative to that of the frame portion 5 and soil working members 7 using the hydraulic piston and cylinder assembly 71, powered from the hydraulic system of the tractor or other operating vehicle, forthat purpose, remembering thatthe adjusting mechanism 73 can beset, as described above, to enable any chosen bodily level of the rol lers 54to be quickly and easily regained afterwork has been discontinued for a time. The speed at which the soil working members 7will all resolve in response to a more or less standard speed of rotation applied to the rotary input shaft 93 ofthe gearbox 91 can be changed, if required, by altering the transmission ratio established in the change-speed gear 92.These adjustments will usually be made having regard to the nature and condition of the soil that is to be dealt with and the particular purpose for which that soil is required after its cultivation. Periodic checking ofthe position ofthe scrapers 64 is also required to ensure correct operation of the implement. As the implement moves operatively in the direction A, the maximum depth of penetration of the tines 9 of its soil working members 7 into the soil which is possible, is governed by the bodily level ofthe "packer" ground rollers 54 relative to that of said soil working mem- bers7.Each pinion 90,shaft6 and soil working member 7 will revolve, due to the inter-meshing arrangement of the pinions 90, in the opposite direction to the or each immediately neighbouring similar assembly as shown by small arrows for most of these assembiies in Figure 1 of the drawings and the distance betweenthetwotines 9 of each member7 is such that the strips of ground, extending in the direction A, that are worked by the individual members 7 overlap, or at least adjoin, one another to produce a single broad strip of worked soil extending in the direction A.With the preferred distance of substantially 25 centimetres that has been discussed above between the axes of rotation of immediately neighbouring members 7,this single broad strip of worked soil will have a width of substantially, although not necessarily exactly, four metres in the case ofthe implementthat is being described. Greater or smaller working widths could be produced by increasing or decreasing the number of soil working members 7 in the single rowthereof and a construction in accordance with the invention is particularly advantageous for an implement having a relatively large working width ofsubstantiallythree metres or more.

Upon temporary removal of the locking pins 33, the screen 28 can be moved either upwardly or downwardly in accordance with either the construction described with reference to Figure 4 orthat des- cribed with reference to Figure 6 of the drawingsto enable, depending upon the chosen working depth, the screen 28 to occupy substantially an optimum protective position for the upper parts ofthe soil working members 7. The levers 24 by which, after removal of the locking pins 33, the screen 28 is moved upwardly or downwardly may, as an alternativeto what has been described and illustrated, be arranged to projoctforwardly with respect to the direction A rather than rearwardlythereof.

As already mentioned, the construction which has been described is particularly advantageous for im plements having a relatively large working width of substantiallythroe metres or more. The carrying frame which is afforded principally by the frame beam 1 is considerably shorter in axial length than is the hollow frame portion 5, preferably having a length which is approximately half that of said frame portionS. The beam 1 provides support forthe hollow frame portion 5 in a mannerwhich adds very considerablyto the rigidity of the latter in apart icularly simple mannerthat is economic as regards both material and weight. As the implement is moving operatively in the direction A, the hollowframe portion Scan move or "float" upwardly and downwardly relative to the frame beam 1 through the intermediary ofthe dual parallelogram linkage4 and is sustained from the ground surface bythe im mediatelyfollowing closely adjacent ground rollers 54. The carrying assem blyfor the rollers 54 which comprises the arms 47 and the upper and lower beams 50 and 51 sustains the carrying frame in a most effective manner which tends to distribute reaction forces exerted upon the implement during its operation in a way which makes breakage or bending damage a very rare occurrence indeed.The simple bearing arrangement at the neighbouring ends of the two ground rollers 54 allows sufficient bodily movement of those rollersto take placeto ac- comodate local ground irregularities and the like without significant disturbance to the cultivating operation. The power-operated bodily displacement of the rollers 54 by the hydraulic piston and cylinder assembly 71 makes any adjustment both quick and easy to perform and the use ofthe adjusting mechanism 73 makes it possible rapidly to regain any advantageous setting after an interruption to work whilst also furnishing means by which the assembly 71 is prevented from having to resistall ofthejolting and other forces to which it would otherwise be sub- joctduring the use ofthe implement.

The implement constructions which have been described also form the subject of our co-pending Patent Application No.8502739 (Serial No.2153642) to which reference is directed.

Claims (5)

1. A soil cultivating implement ofthe kind set forth, wherein said screen is upwardly and downwardly adjustable in position relative to the carriers by the operation of at least one lever, the or each lever being pivotable about an axis which is located above the hollow frame portion between at least two different positions, means being provided to retain the or each lever in any chosen one of those positions.

2. An implement aas claimed in claim 1, wherein said screen is mounted on upright carrying arms which arms are pivotally connected to said lever or levers in front of the fulcrum or fulcrums thereof with respect to the intended direction of operative travel ofthe implement.

3. An implementasclaimed in claim 1 or2, wherein said screen comprises brackets arranged to cooperate movably with corresponding stop brackets mounted onthefrontofsaidhollowframe portion with respect to the intended direction of operative travel of the implement.

4. An implementasclaimed in claim 3,wherein means is provided to urge said brackets resiliently into engagement with said stop brackets.

5. An implement as claimed in claim 3 or4, wherein each stop bracket includes a roller arranged to bear rotatably against the corresponding bracket.