IE45205B1 - Improvements in or relating to rotary harrows - Google Patents

Description

This invention relates to rotary harrows. Italian Patent No. 952,002, describes a harrow capable of weeding and tilling even without a prior plowing operation. The harrow is actioned by a suitable agricultural tractor, is attached to a raising and lowering means of the latter and its accessories are made rotatable by the motive force of the tractor itself.

It is an object of the irvention to improve the construction and operation of such a harrow.

The present invention consists in a rotary harrow, adapted to be towed and driven by a tractor, the harrow comprisingj.a hollow body forming the walls of a tank adapted to contain lubricant; a row of tool shafts, sach tool shaft passing through, and being sealed with respect to, the walls of the tank, each having fixed to it at least two vertical tines arranged for direct engagement with the ground, and each being rotatable about a vertical axis; a first drive shaft, connected by gears to the tool shafts so that the rotational speed relationship between the drive shaft and each tool shaft is invariable; at least one further drive shaft connected by gears to the first drive shaft, so that the rotational speed relationship between the shafts is invariable and so that the drive shafts rotate at different speeds; the gears all being disposed inside the tank; each drive shaft passihg through, and being sealed with respect tc, the walls of the tank, and each having an exposed end, outside the tank, the ends being - 3 4s2Q5 substantially identical, and each end being so shaped that a rotary power take-off shaft of the tractor is releasably connectable to a selected one of the ends, which when connected, is driven thereby.

It is convenient to arrange that the tool shafts each carry a spur gear, which gears intermesh so that all the tool shafts rotate at the same speed, but adjecent shafts rotate in opposite directions.

Preferably, one of the tool shafts also carries a bevel gear which meshes with a bevel pinion carried by a first drive shaft which rotates about a horizontal axis; also carried by the first drive shaft is a spur gear which meshes with a spur gear carried by the second drive shaft which is mounted alongside and parallel to the first, the spur gear carried by the second drive shaft having a different number of teeth from that carried by the first drive shaft.

Preferably, a third Give shaft is provided, also carrying a spur gear which has a different number of teeth from the spur gears on the first two shafts, and which meshes with one of those gears.

The end of each drive shaft is preferably formed with a male spline, onto which may be secured a universally-jointed shaft, coupled to the power take-off shaft of the tractor.

The gears are protected by being contained within the tank, and by being lubricated by the lubricant in the tank. The tank may be provided with a cap for filling and for controlling the liquid level and may be provided also with an inclined conduit, one extremity of -4which is contained inside the tank and the other extremity, suitably bent, emerges from the outside of said tank as to permit the discharge to the outside of any vapors which develop in the inside of said tank during the operational cycle of the unit and also to permit the exit of water of condensation which forms while the harrow is not in operation, yet not to permit the entry of falling v/ater, such as rain water, or washing water.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which:10 Figure ί represents a front view of a harrow, with some sections represented only partially and with some other sections not visible, since they are located on the inside of unit, represented by dashed lines: Figure 2 represents a side view of the harrow; -t .

Figure 3 represents a side view of a tool; Figure 4 represents a section taker, along lines IV - IV of Figure 3; Figure 5 shows in detail a side view; Figure 6 shows a plan view of the detail of Figure 5; and Figure 7 shows a section taken along lines VII-VII of Figure with some 2Q parts omitted. -5^.5205 With reference to the drawings, the harrow comprises a body or tank I having a double bottom and a cover sealed thereon. The double bottom is sealingly crossed by a series of equidistant and parallel tool shafts 3, crossing through the passages 4 of said double bottom and supported by bearings 5. At -its lower extremity each tool shaft carries a head essentially consisting of a radial cross-bar 7 carrying on its ends a tool hoider 9. The tool hoider 9 is formed by a block perforated in an axial direction and presenting an upper square face and a conical lower section. The toolholder 9 has on the square section thereof a hole which permits the passing therethrough of a bolt IO which is used to hold, by means of a nut 12, tool II which also is in correspondence with the hole through the opening 13.

The tool II, which is mounted with its axis parallel to that of the axis of shaft 3, has ar, upper cylindrical section 14 which merges into a gradually narrowing iine 15 which has a triangular cross-section formed by two straight sides and by a concave side such as to present two cutting sharp corners 16 which are suitable for the trituration of stems, stalks and the like.

On the upper section of each tool shaft 3 is located a cylindrical or spur 20 gear 17. All said cylindrical gears 17 are interconnected so that, when one of the shafts 3 is put in motion all the other shafts are also put in motion in alternately opposed directions.

On one of the shafts 3, and exactly on that which is represented in Figures 1 and 7, there is connected a bevel gear 18. Such gear 18 is in turn connected to a bevel pinion 19 keyed on a drive shaft -620 sealingly supported within bearings 21 mounted within the walls of the tank. On the same shaft is mounted a cylindrical or spur gear 22 which is connected with spur gear 23 (Figure I) of a different diameter mounted on a second drive shaft 24. Shaft 24 is in turn supported by the walls of tank I in a manner similar to that of axle 20. Gear 23 meshes with a gear 25 of ?. different diameter, carried by a third drive shaft 25 which is also supported as are the other shafts 20 and 24.

All three drive shafts 20, 24 and 26 extend outwardly from one of the 1 ,47. sides of tank I and the exposed end of each is formed with a spline.

Depending on the rotational speed which one wishes to impart to the toolholding heads 6, one attaches to one of said splined ends a forked cooping 27 which comprises ons of the components of a universally r· jointed shaft 28 through which the motive force of the tractor (not Ϊ5 shown) is transmitted to the harrow.

The universally jointed shaft comprises; a cross-piece 29; a sleeve formed by two flanged sections 30, 31 joined by means of bolt 32; a splined pin 33 carrying a forked coupling 34; a cross-piece 35 and a forked sleeve 36 apt to be connected to the rotary power take-off shaft of the tractor.

On the two coupled flanges 30, 31 of the sleeve is mounted a ring 37 having a C-section. The connection by means of bolts 32 between the two flanges 30, 31 of the sleeve make it possible to prevent, by allowing the bolts 32 to shear, the damage which could arise from -7the operation of the harrow against a blocking or fouling of the toolholder heads 6.

On each side of tank I is mounted a plate 47 which extends beyond the structural shapeof the tank. In the extending sections of the plate there are provided a series of holes 38 the function of which is to permit the passage of the bolts which permit the fixing of arms 39, which support between their extremities the axle 40 of a roller 41. The roller 41 may have a series of equidistant ribs 42, The arms are provided with holes 51 which permit affixing thereto, by means of nuts and bolts, lateral walls '52 at the desired height, the function of said walls being that of preventing an undesirable scattering of stones or soil while the ground is being worked by means of tines 15.

The harrow, which receives its motive force from the tractor through the universally jointed shaft 28, is connected to the tractor itself at three separate points. For this reason, tank I has mounted thereon a frame 55, comprising metallic bars which support on the upper sections thereof a pair of parallel plates 56. spaced from each other and having holes preformed therein, between which plates is affixed by means of bolts or pins a threaded shaft 58 which is adapted to thread!ngly engage a corresponding threaded female hole of an end section 59 of a double-action oleodynamic jack GO.

The double-action oleodynamic jack comprises a cylinder 61, a piston 62 and a stem 63 through which said jack is connected to -8the raising and lowering apparatus of the tractor. The two chambers of cylinder 61 are alternatively connected with a source of fluid under pressure or with a discharge tank through valve 62 which is controlled by the operator of the tractor. The piping network, which connects jack 60 to valve 62 and the latter to the oleodynamic circuit of the tractor (the circuit also includes the source of fluid under pressure and the discharge tank already mentioned), are respectively indicated by 63, 64, 65 and 66. The operator may, consequently, by acting on valve 62, tilt in one direction or the other the harrow, using as a fulcrum roller 41 which rests on the ground, if, by reason of the sinking of ths tractor into theterrain, he wishes to avoid that the weight of the grubber would further increase the degree of sinking- of the tractor.

The harrow is additionally connected to two other points or arms of the tractor by means of loose connections which permit the relative movements necessary to avoid the possibility that excessive stresses are exerted upon the arms of the tractor when, during operation, there are encountered discontinuities of the terrain. These connections include a pair of tubular rods 70 affixed to the tank and having transversal holes therethrough. On the internal section of the tubular rods 70 is disposed a tubular body 71 having a diameter less than that of the holes wiiich go through tubular rod 70. A stud connects body 71 to rods 70. The stud passes through coinciding holes provided in both rods 70 and body 71.In order to provide a degree of play in the vertical plane, yet not in the horizontal plane, within the interspace between body 71 and rod 70 there are inserted two -0ί> 2 ίϊ 5 νleiiien;.. r.i, ul mmpIciiiuut.ir-v -.iiape tu the mUilui ^duLion ui the rod 70. Body 71 can therefore oscillate to a certain extent on a vertical plane. Body 71 presents an eyelet or grommet 72 through which the harrow is connected to the arms of the tractor.

The gears 22,13, 17 and bevel pinon 19 remain immersed in the-lubricating oil The level of said oil is controlled by a standard level detector 80 provided with a screw cap. More precisely, the level of the oil reaches approximately that indicated by 81.

To permit the exhaust of gases of the lubricating oil which develop IG during operation of the harrow, and to guard against the ingress of condensation water into the oil when the harrow is not operating, and further to prevent the possibility that, when the harrow is washed, some of the wash water may enter the oil chamber, there is provided a conduit 82, incliiied with respect to a horizontal plane, which on the lower seccon thereof extends by means of neck 83 to the outside of the tank, while the interior section terminates, after an elbow section, with a neck directed downwardly. Said tube is affixed, for example, by welding, to the tank. It is evident that, during the time in which the harrow is functioning the gases released by the lubricating fluid can be discharged to the outside while, during the non-operating time and therefore during the time the lubricating oil goes through a cooling phase, the pressure compensating air entering tank through tube 82 condenses the vapors contained therein within said tube which, by reason of its outward pitch, carries said condensates outside the tank without contaminating the lubricating oil contained therein.

Claims (12)

1. A rotary harrow, adapted to be towed and driven by a tractor, the harrow comprising; a hollow body forming the walls of a tank adapted to contain lubricant; a row of tool shafts, each tool shaft passing through, and being sealed with respect to, the walls of the tank, each having fixed to it at least.two vertical tines arranged for direct engagement with the ground, and each being rotatable about a vertical axis - a first drive shaft, connected by gears to the tool shafts so that the rotational speed relationship between the drive shaft and each tool shaft is invariable; at least one further drive shaft, connected by gears to the first drive shaft, so that the rotational speed relationship between the shafts is invariable, and so that the drive shafts rotate at different speeds; the gears all being disposed inside the tank; each drive shaft passing through, and being sealed uith respect to, the walls of the tank, and each having an exposed end, outside the tank, the ends being substantially identical, and each end being so shaped that a rotary power take-off shaft of the tractor is releasably connectable to a selected one of the ends, which when connected, is driven thereby.

2. A harrow as claimed in claim 1 in which the tool shafts each carry an identical spur gear, which gearsintermesh so. that all the tool shafts rotate at the same speed, but adjacent shafts rotate in opposite directions.

3. A harrow as claimed in claim 1 or claim 2, in which one of the tool shafts carries a bevel gear which meshes v/ith a bevel pinion carried by a first drive shaft which rotates about a horizontal axis; also carried by the first drive shaft is a spur gear, which meshes with a spur gear carried by the second drive shaft which is mounted alongside -ΙΙand parallel to the first, the spur gear carried by the second drive shaft having a different number of teeth from that carried by the first drive shaft..

4. A harrow as claimed in claim 3, in which a third drive shaft 5. Is provided, also carrying a spur gear which has a different number of teeth from the spur gears on the first two shafts, and which meshes with one of those gears.

5. A harrow as claimed in any preceding claim, in which the end of each drive shaft is formed with & male spline, onto which may be Ιΰ secured a universally-jointed shaft, coupled to the power take-off shaft of the tractor.

6. A harrow as claimod in any preceding claim, in which each tine is of triangular section, narrowing towards the lowermost end of the tine, one of the sides of the section being curved in a concave sense. 15

7. A harrow as claimed in any preceding claim, and which includes a supporting member which rests upon the ground, and relative to which the height of the body is adjustable, so that the depth of penetration of the tines into the ground is adjustable.

8. A harrow as claimed in claim 7, in which the body may be tilted 20 about the supporting member by operation of a hydraulic device, so that the tines may be selectably raised out of the ground, without disturbing the adjusted height of the body. -129. A harrow according to any preceding claim, in which within the tank there is disposed a tube inclined v/ith respect to a horizontal plane, the lowermost extremity of said tube emerging from said tank with a downwardly disposed neck which serves to discharge water of condensation, 5 to avoid contamination of the lubricating fluid, and to permit the discharge of any gases generated by the lubricating fluid during operation of tha unit.

9. 10. A.harrow according to any cf the preceding claims, in which the harrow is connected to the arms of the tractor, by a connecting means 10 which permits a relative movement in a vertical plane between the body and the arms.

10. 11. A.harrow according to any of the preceding claims, in which one of the drive shafts is driven through a universally jointed shaft, which includes a shearable coupling which disengages the drive shaft from the 15 tractor in the event of an abnormal load on the harrow.

11.

12. A harrow constructed and adapted to operate substantially as described herein with reference to the accompanying drawings.