WO1991010350A1

WO1991010350A1 - Agricultural weeding apparatus

Info

Publication number: WO1991010350A1
Application number: PCT/AU1991/000022
Authority: WO
Inventors: William Nicholas Chivers; David Charles Mcgrath
Original assignee: Sustainable Agricultural Machinery Developments Pty. Ltd.
Priority date: 1990-01-19
Filing date: 1991-01-18
Publication date: 1991-07-25
Also published as: AU6256090A

Abstract

Agricultural weeding apparatus incorporates a number of horizontal cutting blades (11, 12; 48) supported on carriers (10; 47) which incorporate drive mechanisms (21, 22, 25; 64, 66, 65). The blades (11, 12; 48) are caused to move arcuately by the drive mechanisms in an oscillating movement between a raised position and a ground-penetrating position. The depth of penetration is controlled by a wheel (42; 57) or skid (3) adjustably mounted to the carriers (10; 47). The wheel (42; 57) engaging with the ground is steerable such that the weeding apparatus may track independently of a towing vehicle, and the depth of penetration is monitored by an upstanding indicator portion on each of the horizontal cutting blades.

Description

AGRICULTURAL WEEDING APPARATUS Field of the Invention

This invention relates to agricultural weeding apparatus of the type capable of removing unwanted vegetation from beds of crops, including vegetable crops such as onions, carrots and the like, and row crops such as cotton, soy bean, seed tomatoes, and the like. Background of the Invention

There have been many proposals for weeding apparatus employing different forms of cutter blades and using different movement patterns of the blades through the soil area to be weeded. In one simple form, one or more generally horizontal single blade cutter or scraper is passed through the soil to cut the vegetation. In an improved form of this type of weeder the blade or blades are reciprocated in a generally horizontal plane. This type of apparatus requires considerable force and a relatively large tractor is required to carry the blades or scrapers through the soil. However, tractors are difficult to steer accurately and consequently considerable concentration and skill is required to weed ground crops by this method.

Furthermore with this type of apparatus the cutting blades or scrapers generally remain below ground level which promotes the tendency of weeds to build up on the cutting edge of the cutting members until such time as the cutting edge becomes totally ineffective. Moreover certain types of weed growths are resistant to this form of cutting operation and these weeds accentuate the problem. With this type of apparatus, the operator spends a considerable amount of time simply cleaning the blades. Alternatively apparatus has been employed using rotary hoes or other rotating cutter members designed to remove unwanted vegetation from vegetable beds. Apparatus of this type tends to chop the weed growths but does not necessarily destroy the growth. It has been found that weed growths which have been disturbed by rotating cutting members such as rotary hoes tend to restart growth very quickly. Background Art

An improved arrangement was described in Australian Patent No. 509,148, the specification of which discloses mechanical weeding apparatus comprising a supporting frame adapted to be attached to a tractor or the like, and including at least one cutting blade having a cutting edge arranged dependent from a rocker shaft associated with the supporting frame, the rocker shaft being powered such that it reciprocated over a predetermined angle of movement.

A disadvantage of the disclosed apparatus is that when more than one cutting element is provided to give the ability to till more than one row, the apparatus becomes very sensitive to irregularities in the ground level in the respective rows. In extreme circumstances, a particularly low row may not be tilled at all, with the blades of the reciprocating cutter being held above the surface of the soil by the tool bar, the height of which would remain at the operating height determined by the soil level in the other rows. The present invention aims to alleviate the above disadvantages and to provide weeding apparatus which will be reliable and efficient in use. Other objects and advantages of this invention will hereinafter become apparent. Summary of the Invention

In accordance with one aspect of the invention there is provided a weeding apparatus for weeding between multiple rows of a row crop comprising a plurality of cutter hoe blades having substantially horizontally extending cutting edges, said blades being supported in a plurality of carrier means mounted on an elongated support member, said carrier means being spaced apart a predetermined distance along said support member and including drive means for imparting an oscillatory movement to said blades whereby said blade cutting edges are caused to move in an arc between a forward ground engaging position and an upper rearward position above the ground, and ground engaging means pivotally and adjustably mounted on each carrier means to regulate the height of each carrier means and the cutter blades relative to the ground. The elongated support member may comprise a rectangular frame adapted to be connected on one side thereof to the 3-point linkage of a tractor or like prime mover and said carrier means may be mounted, along the other side of the frame.

The carrier means may comprise a generally L-shaped casing with the upstanding leg thereof secured to said frame with the ground engaging means connected to the outer end of the horizontally extending leg of the carrier means with the cutter blade depending downwardly through said horizontally extending leg.

The drive means for imparting the oscillatory movement to the cutter blade may comprise a hydraulic motor mounted on the upper part of the upstanding leg of a carrier means member drivingly connected to a common drive shaft extending through all the carrier means. The drive shaft is preferably connected through gear means to a cam member connected by link means to the upper end of an arm member supporting the cutter blade at its lower end. The arm member is conveniently pivotally mounted in the horizontally extending leg of the carrier means enclosure member. The cam members or groups of cam members are mounted so that the cutter blades or groups thereof are driven out of phase with each other so as to reduce the load on the hydraulic motor and drive shaft. The weeding apparatus of the invention also preferably includes sensing means attached to said elongated support member for sensing the distance between the outer edge or edges of the cutter blades and the crop in each row to ensure correct lateral positioning of the cutter blades to the crop. The sensing means transmits a signal to actuating means on the support member to move same and correct any lateral deviation of the path of the apparatus through the crop. The sensing means may comprise a pair of highly sensitive wands mounted on the support member and located between adjacent rows of the crop whereby the wands can contact the foliage or stems of the crop plants and transmit lateral movement thereof to an electronic control box which in turn transmits a signal to the actuating means on the support member to move the support member in the required direction and correct the travel path of the apparatus.

An alternative sensing means may comprise a sled member engageable with the sides of a furrow between the crop rows and in like manner to the sensing wands transmits any lateral movement of the side members of the sled to the electronic control box. A further sensing means usable in a furrow may comprise a pair of bullet nose shaped members attached to the ends of a pair of arms connected to the control box and operating in similar manner to the sled member.

The lateral movement of the support frame may be effected by mounting on each end of the support member a frame support wheel and a disc member engaging the inner side of a furrow, the two discs being adjusted towards each other and "locked" in both furrows against lateral movement therein. Each disc and wheel of a set are fixedly connected to the support frame through a housing carrying a hydraulic cylinder and piston actuated spindle, the outer end of which is connected by linkage to the disc and wheel. The signal from the electronic control box from the sensing means is transmitted to the hydraulic cylinder in known manner for actuation thereof to correct any sensed deviation of the path of the apparatus. Movement of the spindle and attached linkage tends to move the disc and wheel relative to the housing but as both discs are firmly engaged in the furrows against each other there can only be a resultant movement of the support frame relative to each disc and wheel pair.

The support frame and its carrier means may be conveniently located at the rear or front of the tractor so as to be pulled or pushed in operation. Accordingly, in another embodiment, this invention resides broadly in mechanical hoeing apparatus including a supporting frame, ground engaging means adapted to support the supporting frame, a tool arm pivotally mounted to said supporting frame and having a cutting blade mounted at its lower end, and drive means adapted to oscillate said tool arm, said cutting blade having a mounting portion, a cutting portion and a position indicating portion, wherein the location in use of the cutting blade beneath the soil may be monitored, and wherein the cutting edge of said cutting portion is swept forward of said mounting portion in the direction of travel of the hoeing apparatus.

Preferably, the supporting frame takes the form of a rigid member adapted for attachment to a source of motive power such as a tractor or the like. For example, in embodiments of the apparatus adapted to be towed behind a tractor, the supporting frame may be attached to the tractor by a conventional three point linkage or alternatively via a trailer hitch. Of course it is also envisaged that the apparatus may be self powered and accordingly provided with the necessary drive and control means, or may be pushed by or slung underneath a tractor.

In order to provide the apparatus with the ability to follow the terrain, the supporting frame may comprise a tool bar adapted to be attached to the tractor and the like and a body portion bearing the tool arm and being supported on the ground engaging means. The tool bar and body portion are preferably interconnected by a linkage permitting limited vertical relative motion between the tool bar and the body portion. Preferably, the linkage is of a type permitting such vertical relative movement whilst maintaining the vertical orientation of the tool arm, such as may be achieved by the use of a pair of equal length arms describing a parallelogram between their pivot points. In one preferred embodiment of the present invention, the pair of equal length arms consists of a rigid inextensible link pivoted at both ends and a leaf spring link or other flexible member rigidly mounted to one of the tool bar or the body portion, and pivotally mounted to the other.

The ground engaging means adapted to support the supporting frame preferably takes the form of a wheel. However, the ground engaging means may take any form consistent with its function of supporting the frame above the ground, such as a skid or skids, tracks or the like. The preferred wheel may be a jockey wheel permitting the apparatus to track with the tractor or the like. Alternatively, the preferred wheel may be fixed in direction relative to the supporting frame or be steerable by positive steering input from an operator.

The tool arm is pivotally mounted to the supporting frame and bears a cutting blade mounted at its lower end. Preferably, the cutting blade is a hoe blade selected from the hoe blades described above. Pivotal mounting of the tool arm may be achieved by any suitable means including a shaft and bushing or bearings.

The drive means may take any form consistent with the function of being adapted to oscillate the tool arm. Preferably, the drive means is selected from the group comprising hydraulic motors or direct power take off from the tractor or the like. Alternatively, the drive means may include a belt, chain or gear train taking power from the preferred ground engaging wheel. In any case, the oscillating movement of the tool arm is preferably achieved by coupling the rotary movement of a crank driven by the power source to the tool arm by means of a connecting rod.

In a preferred embodiment of the present invention, there are provided a plurality of hoeing apparatus on a tool bar in order to cultivate multiple rows of a crop in a single pass. Accordingly, in a further aspect, this invention resides broadly in mechanical hoeing apparatus suitable for use in for hoeing multiple rows of a row crop or the like and including a tool bar, a plurality of hoe assemblies mounted in spaced relationship along said tool bar, and a linkage for attaching said tool bar to the rear or front of a tractor or the like, each of said hoe assemblies including a supporting frame, ground engaging means adapted to support the supporting frame, a tool arm pivotally mounted to said supporting frame, a cutting blade mounted at the lower end of said tool arm, and drive means adapted to oscillate said tool arm, wherein said ground engaging means are steerable such that the hoeing apparatus may track independently of said tractor or the like.

Preferably, the tool bar extends across the full width of the rows to be cultivated in a single pass, the tool bar being preferably adapted to mount a selectable number of hoe assemblies. In order to permit the apparatus to cope with irregularity in the ground level between the rows, the tool bar may be articulated in sections, preferably having an articulation for every one or two hoe assemblies. There may be provided a linkage for attaching said tool bar to a tractor or the like, either operated off the 3 point linkage for drawing in the normal manner, or alternatively linked to the front or underbelly of a tractor for pushing thereby.

The plurality of hoe assemblies mounted in spaced relationship along the tool bar are preferably of the type described above and having a ground engaging wheel supporting a body portion linked to the tool bar via a resilient parallelogram linkage. The hoe assemblies are preferably of the steerable type and having the steering mechanism of each of the hoe assemblies interconnected such that the hoe assemblies may be steered in concert. The interconnecting member may be provided with universal joints interposed along its length to prevent the outer wheels loading the steering mechanism in response to passage over unevenness in the ground. The apparatus may be provided with accommodation for a second operator to precisely steer the tool bar within the confines of any side drift of a standard 3 point linkage. Alternatively, the 3 point linkage may be modified to increase the available side drift, for example, by the use of universal or ball type joints in the linkage. In apparatus so configured, the amount of permitted side drift may be limited by limit chains interposed between the tractor and the tool bar to prevent the tool bar moving to the extent that, for example, the tractor wheels are fouled.

Of course, where the apparatus is disposed ahead of or under the tractor, similar arrangements may be made for guidance of the tool bar by a second operator. One advantage of the positioning of the tool bar beneath or ahead of the tractor may be that the hoeing apparatus may be configured to remove weeds very close to the crop in the front operation whilst a second apparatus mounted to the rear of the tractor cleans the weeds from irrigation furrows and shoulders in the one operation. The tool bar mounted in front may also remove the necessity for the unproductive counterbalance weights usually required where the tool bar is rear mounted.

Alternatively to the provision of a second operator there may be provided a self steering system adapted to steer the tool bar within limits under the control of control means responsive to a sensor adapted to locate the correct path for the tool bar. The sensor in this case may take any known form consistent with the function of actuating a steering mechanism to guide the tool bar along the correct path. For example, the sensor may be an electronic or electro-optical device exercising electrical control over an electro-hydraulic steering actuator, sensing means as in the previous embodiment, or may be simply a mechanical follower adapted to follow a wire strung along a representative row and in following the wire provide moving input to an appropriate controlling means for the actuator.

The drive means may take any form consistent with the function of driving each tool arm to effect the reciprocating hoe action. Preferably, the drive means includes a central source of motive power such as a hydraulic pump or power take off point on the tractor, coupled to common or individual activators. For example, the power take off shaft of the tractor may drive a bevel gear box on the tool bar, the bevel gear box in turn driving a shaft substantially parallel with the tool bar and extending to the outermost hoe assemblies. The individual hoe assemblies may draw power from the shaft via, for example, drive chains or the like. Alternatively, each hoe assembly may be provided with its own hydraulic motor adapted to be connected to the central hydraulic pump of the tractor.

Where a common shaft approach to driving the hoe assemblies is adopted, it is preferred that the shaft be articulated by the incorporation of constant velocity or universal joints in the shaft to prevent loading of the shaft under flexion as the apparatus traverses uneven ground.

Preferably, the hoe assemblies are driven out of phase with one another to keep a reduced and more constant load on the drive, resulting in less wear and a lower power requirement compared with apparatus where the hoes reciprocate in phase. Accordingly, it is preferred that the out of phase motion of the hoes be maintained such as is the case where the driving shaft runs the full length of the tool bar and has sprockets fitted to drive each hoe or at least each pair of hoes. Where the width of the space between the rows permits, it is preferred to provide two hoe assemblies per row, each hoe assembly being adapted to till one side of the crop row. Where the space is too narrow to permit two hoe assemblies side by side, the hoe assemblies may be disposed one behind the other. Alternatively, a single hoe assembly may be provided with a pair of hoe blades, each blade being adapted to till one side of adjacent rows of the crop with the bend or heel in the centre of the area between rows and the hoe blades in close proximity to the row.

Preferably, the hoe blade is mounted on the tool arm such that the tool arm is disposed away from the row by the length of the cutting edge of the hoe blade. This configuration has the advantage of allowing the hoe blade to pass under any overhanging foliage when cultivating crops such as beans, cabbages or the like.

The cutting edge of the hoes may be swept backwards away from the tool arm to give a slicing action through the roots of weeds. Alternatively, the toe of the hoe may be swept forward of the tool arm rather than behind to carry any clods, weed foliage and so on away from the rows of young crops.

Apparatus in accordance with the present invention may be adapted to till a set number of rows. Alternatively, the configuration of the apparatus may be variable to suit a variety of conditions. For example, the tool bar, drive shafts and other components such as steering mechanism may be provided in add-on lengths such that the number of hoeing elements may be varied up to the limit of the tractor's ability to draw the apparatus. The spacing of tiie hoeing elements along the tool bar may also be variable.

In order that this invention may be more easily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate the preferred embodiments of the invention. Description of the Drawings

Figure 1 is a plan view of one embodiment of the weeding apparatus connected behind a tractor;

Figure 2 is a rear view of the weeding apparatus of Figure 1; Figure 3 is a section along the line 3-3 of Figure 1;

Figure 4 is a view along the line 4-4 of Figure 1;

Figure 5 is a view from the right hand side of Figure 4; Figure 6 is a part-sectional view along the line 6-6 of Figure 3; Figure 7 is a schematic layout in plan of a second embodiment of the invention;

Figure 8 is a side view taken along the line 8-8 of Figure 7; Figure 9 is a side view of an alternative drive means to Figure 8;

Figure 10 is perspective views of one form of cutter hoe blade of this embodiment; and

Figure 11 is perspective views of alternative hoe blade to that of Figure 10. Description of the Preferred Embodiments Referring to the embodiment of Figures 1 to 6, the weeding apparatus illustrated consists of a support frame 5 adapted to be connected in known fashion to and towed by a tractor 6. Frame 5 is of rectangular configuration having side members 7 and 8 and end members 9. It will be appreciated that a single tow bar may be substituted for frame 5 and frame 5 may be conveniently mounted on a tractor tow bar.

Mounted on side member 8 are a plurality of carrier members 10 spaced apart a predetermined distance along side member 8 said carrier members supporting cutter blades 11 and 12 between rows of the crop 13 being weeded. Blades 11 are configured to weed between adjacent rows of corp and blades 12 are configured to weed on one side of a crop row. It will be noted from Figure 2 that cutter blades 11 can be mounted in carrier members 10 to be offset right or left and blades 12 can be mounted in carrier members 10 either for left hand or right hand operation. Whilst blades 11 have been illustrated as depending from a single arm 14, they may be incorporated in a stirrup type configuration with the transverse bar of the stirrup constituting the cutter blade, sharpened on both edges.

As shown in more detail in Figure 3, the carrier members comprise an L- shaped casing 15 housing drive means for cutter blades 11 and 12, casing 15 being fixedly attached to side member 8 by a U-shaped bracket 16 welded to casing 15 and secured by gib 17 to side member 8. The drive member for all carrier members comprises a common square drive shaft 18 driven by a single hydraulic motor 19 mounted on the upper part of a casing 15, as shown in Figures 1 and 2, and connected by chain and sprocket drive to shaft 18 which is in driving connection with a gear 20 meshing with^" an idler gear 21 in turn meshing with gear 22. Gear 22 is mounted on a cam drive wheel 23 having an offset pin 24 pivotally connected to one end of a link

25 which at its other end is pivotally connected to the upper part of oscillating arm

26 supporting a cutter blade 11/12 at its lower end. Arm 26 is pivotally mounted towards its upper end at 27 in casing 15. Pivotally mounted at the rear end of casing

15 is a parallel linkage 28 connected at the upper part thereof to a manually adjusting member 29 and the lower ends of the linkage are connected to a ground engaging skid member 30 adjustable vertically relative to casing 15 through adjusting member 29 so as to ensure that blades 11/12 engage in the ground 31 to the desired depth of approximately *s inch so as to cut the foliage from the weeds at the crown thereof and thus greatly minimise any further growth by the cut weed.

Preferably the location of pin 24 on cam wheel 23 is at a different peripheral location in the several casings 15 so as to drive the oscillating cutter blades 11/12 out of phase and thus reduce the load on hydraulic motor 19 and drive shaft 18 by not being in ground engagement at the same time.

In order to achieve a maximum weeding effect it is preferable that the outer edges of cutting blades 11/12 operate at a distance of approximately % inch from the stems of the row crops and in order to ensure that this clearance can be attained and held, this embodiment incorporates sensing means to sense the lateral drift of the apparatus in use and bring it back to the correct path and obviate damage to the crop.

This adjustment of the lateral location of cutter blades 11/12 may be achieved in a number of ways by use of sensor members located on the support frame 5 and adapted to locate the lateral position of the apparatus in relation to the stems or foliage of the crop or the sides of a furrow between rows of crops. One form of sensing means is a pair of highly sensitive wands 32 connected to an electronic control box 33 on support frame 5 through a sensitive axle means 34 whereby on engagement of either wand 32 with the crop foliage or stems a signal is transmitted through the control box 33 to actuating means 35 on support frame 5 to move the support frame 5 and its attached casings 15 laterally in the required direction to correct the path of the cutter blades 11/12 between the crop rows and ensure the correct clearance between the ends of the cutter blades 11/12 and the crops.

As a number of row crops require the provision of furrows between rows, or a number of rows, for irrigation purposes another form of sensor means may be a pair of skid members 36 engaging against the sides of a furrow and connected to axle means 34 to provide a signal from control box 33 to actuating means 35 when pressure or lack of pressure is signalled by the control box 33 to actuating means 35 to energise same for movement of support frame 5 in the required direction. ^"

Also the sensor means may consist of a pair of bullet nose members mounted on the ends of arms or wands and operating in a furrow in similar manner to the skid members.

The actuating means 35 of this embodiment may consist of two wheel and disc pairs 37 mounted at the outer ends of side member 7 of the support member 5 and connected to said side member 7.

As illustrated in Figures 1, 4 and 5, the actuating means 35 comprise a housing structure 38 fixedly mounted on side member 7 of support frame 5 and incorporating a hydraulic cylinder 39 operable on receipt of a signal transmitted from control box 33 to move its piston actuated spindle 40 in either direction. Spindle 40 is connected by linkage 41 to apply a lateral movement to support wheel 42 and furrow engaging disc 43 as indicated in Figure 4. Before the apparatus is put into operation, the discs

43 at each end of support member 5 are adjusted on structures 38 so as to firmly engage said discs 43 against the inner edge of their furrows and structures 38 are then fixedly connected to side member 7 of support frame 5 so as to "lock" in the discs to prevent any lateral movement thereof in relation to the engaged sides of the furrow. On actuation of spindle 40 the discs 43 and associated support wheels 42 cannot, by reason of prior adjustment and "locking" in on the inner sides of the outer furrows, move laterally and consequently a reaction force is transmitted to the support frame 5 to move it in the requisite lateral direction to correct the path of the apparatus.

According to another embodiment of the invention there is illustrated in Figures 7 to 11 multiple row hoeing apparatus suitable for drawing behind a tractor

44 in a tool bar 45 is adapted to be mounted via a three point linkage 46 to the rear of a tractor 44.

Affixed to the tool bar 45 are hoe assemblies 47 each enacted to drive a hoe blade 48 via tool arm 49. Each hoe assembly 47 consists of a body portion 50 rigidly mounted to the tool bar 45 and the hoe carrier 51 supporting the tool arm 49 via pivot 52. The body portion 50 and the hoe carrier 51 are interconnected for parallel movement via a fixed length lower link 53 and upper link 54. Upper link 54 provides for resilient relative movement between the body portion 50 and the hoe carrier 51 by being comprised of a leaf spring member rigidly affixed to the body portion 50 at mount 55 and pivotally mounted to the hoe carrier 51 at 56.

The height of the hoe carrier 51 and hence the hoeing depth of the blade 48 is determined by the setting of an adjustable height wheel 57 mount to the hoe carrier 51 via a height adjustable stem 58 and caster arm 59. Height adjustability is provided for the wheel 57 by threaded region 60 and threaded collar 61 journalled to the hoe carrier 51.

In order to permit clearance of the hoes at the end of the row by elevation of the tool bar 45 there is provided a limit chain 62 interposed between the body portion 50 and the hoe carrier 51 to limit the downward displacement of the hoe carrier 51 relative to the body portion 50.

The drive to the oscillating tool arm comprises a drive shaft 63 extending substantially the length of the tool bar 45 and adapted to drive each of the hoe assemblies 47. Drive for each of the hoe assemblies 47 is provided via sprockets 64 keyed to the drive shaft 63. The drive shaft 63 may be driven by any suitable means including a hydraulic motor or gearbox from the tractor power take-off.

The sprockets 64 are connected to corresponding driven sprockets 65 on the hoe carrier 51 by a drive chain 66. The rotary motion of the driven sprocket 65 is translated to an oscillating motion of the tool arm 49 by interconnection of these elements by a pivoting connecting rod 67.

In the alternative drive illustrated in Figure 9 a drive pulley 68 is mounted for rotation with wheel 57 and drives a driven pulley 69 via a drive belt 70 which in turn drives the connecting rod 67 as before.

In the embodiment that is illustrated in Figure 8 a chain tensioner 71 is provided such that the chain 66 maintains driving tension throughout the range of relative movement between the body portion 50 and the hoe carrier 51.

When the appropriate height is set by means of the threaded collar 61 the collar is locked to the stem 58 by means of locking key 72 such that the handle 73 of the collar 61 may be linked to a steering bar 74 into connecting handles 73 of each of the hoe assemblies 47 in turn. The steering bar 74 is controlled by a second operator from second operator seat 75 mounted to the tool bar 45 about the region of the 3 point linkage 46. Second operator position 75 may then be used to steer the tool bar 45 and attendant hoe assemblies 47 within the lateral movement limit provided for by the 3 point linkage 46.

The hoe blades suitable for use with this apparatus illustrated in Figures 10 and 11 which are directed to a swept rearwardly hoe blade and a swept forward hoe blade respectively. In each case the blade is provided with an upstanding mounting member 76 adapted to be rigidly affixed to the tool arm 49 via a plain stud provided in the tool arm 49 cooperating with a corresponding stud hole 77 provided in the mounting portion 76. To lock the hoe blade 48 to the tool arm 49 there is provided a threaded hole 78 and a corresponding threaded hole in the tool arm 49 adapted to receive a bolt (not shown). The hoe blade illustrated in Figure 10 comprises a sharpened leading edge 79 swept rearwardly back from the forward edge of the mount portion 76 and adapted to slice through weed, roots and the like. The trailing edge 80 of the hoe blade 48 is relatively thick to provide rigidity.

The hoe blade illustrated in Figure 11 has its leading edge 81 swept forward so that the leading edge of the mounting portion 76 is provided at its outer end with an upstanding indicator portion 82 to provide indication of the position of the hoe blade in use.

It will of course be realised that while the above has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is herein set forth.

Claims

Claims :-

1. A weeding apparatus for weeding between multiple rows of a row crop comprising a plurality of cutter hoe blades having substantially horizontally extending cutting edges, said blades being supported in a plurality of carrier means mounted on an elongated support member, said carrier means being spaced apart a predetermined distance along said support member and including drive means for imparting an oscillatory movement to said blades whereby said blade cutting edges are caused to move in an arc between a forward ground engaging position and an upper rearward position above the ground, and ground engaging means pivotally and adjustably mounted on each carrier means to regulate the height of each carrier means and the cutter blades relative to the ground.

2. A weeding apparatus according to Claim 1 wherein the elongated support member comprises a rectangular frame adapted to be connected on one side thereof to the 3-point linkage of a tractor or like prime mover, said carrier means being mounted along the other side of the frame.

3. A weeding apparatus according to Claim 1 or Claim 2 wherein the carrier means comprises a casing housing the drive means and supporting the cutter blade through a pivotal arm member.

4. A weeding apparatus according to Claim 3 wherein the carrier means casing is of generally L-shaped configuration with the upstanding leg thereof secured to said frame, the ground engaging means being connected to the outer end of the horizontally extending leg of the casing, and said pivotal arm member supporting the cutter blade depending downwardly through said horizontally extending leg.

5. A weeding apparatus according to any one of the preceding claims wherein the drive means for imparting an oscillatory movement to the cutter blades comprises a hydraulic motor mounted on one of said carrier means and drivingly connected to a common drive shaft extending through all the carrier means.

6. A weeding apparatus according to Claim 5 wherein the common drive shaft is connected through gear means to a cam member connected by link means to the upper end of a pivotal arm member supporting the cutter blade.

7. A weeding apparatus according to Claim 6 wherein the cam members of the drive means are mounted so that the cutter blades or groups thereof are driven out of phase with each other so as to reduce the load on the drive motor and the drive shaft.

8. A weeding apparatus according to any one of the preceding claims and including sensing means attached to said elongated support member for sensing the distance between the outer edge or edges of the cutter blades and the crop in each row to ensure correct lateral positioning of the cutter blades to the crop.

9. A weeding apparatus according to Claim 8 wherein the sensing means transmits a signal to actuating means on said elongated support member to move same and correct any lateral deviation of the path of the apparatus through the crop.

10. A weeding apparatus according to Claim 9 wherein the sensing means comprises a pair of highly sensitive wands mounted on the elongated support member and located between adjacent rows of the crop whereby the wands can contact the foliage or stems of the crop plants and transmit lateral movement thereof to an electronic control box which in turn transmits a signal to the actuating means on the support member to move the support member in the required direction and correct the travel path of the apparatus.

11. A weeding apparams according to Claim 9 wherein the sensing means comprises a sled member located on the support member and consisting of two side members engageable with the sides of a furrow between the row crops whereby lateral movement of the side members is transmitted to an electronic control box which in turn transmits a signal to the actuating means on the support member to move the support member in the required direction and correct the travel path of the apparatus.

12. A weeding apparatus according to Claim 9 wherein the sensing means comprises a pair of bullet nose shaped members attached to the ends of a pair of arms and engageable with the sides of a furrow between the row crops whereby lateral movement of the arms is transmitted to an electronic control box which in turn transmits a signal to the actuating means on the support member to move the ^"support member in the required direction and correct the travel path of the apparams.

13. A weeding apparatus according to any one of Claims 9 to 12 wherein the actuating means comprises a pair of housings each fixedly mounted at the ends of the support member, each said housing carrying a hydraulic cylinder and piston actuated spindle, said spindle being connected by linkage to a frame support wheel and a disc member which engages the inner side of a furrow, said disc members being adjusted towards each other and locked in both furrows against lateral movement therein, whereby actuation of said spindle on receipt of a signal transmitted from said control box applies pressure to said firmly engaged disc members resulting in lateral movement of the support member.

14. A weeding apparatus according to any one of the preceding claims which is connected to the rear of a tractor to be pulled thereby.

15. A weeding apparams according to any one of Claims 1 to 13 which is connected to the front of a tractor to be pushed thereby.

16. A weeding apparatus comprising a supporting frame, ground engaging means adapted to support the supporting frame, a tool arm pivotally mounted to said supporting frame and having a cutting blade mounted at its lower end, and drive means adapted to oscillate said tool arm, said cutting blade having a mounting portion, a cutting portion and a position indicating portion wherein the location in use of the cutting blade beneath the soil may be monitored, and wherein the cutting edge of said cutting portion is swept forward of said mounting portion in the direction of travel of the apparatus.

17. A weeding apparatus according to Claim 16 wherein the supporting frame comprises a tool bar adapted to be attached to a tractor and having a body portion bearing the tool arm and being supported on the ground engaging means.

18. A weeding apparatus according to Claim 17 wherein the tool bar arid body portion are connected by a linkage permitting limited vertical relative motion between the tool bar and the body portion.

19. A weeding apparatus for use in weeding multiple rows of a row crop, comprising a tool bar, a plurality of cutting blade assemblies mounted in spaced relationship along said tool bar and linkage for attaching said tool bar to a tractor, each of said cutting blade assemblies including a support frame, ground engaging means adapted to support the supporting frame, a tool arm pivotally mounted to said supporting frame, a cutting blade mounted at the lower end of said tool arm, and drive means adapted to oscillate said tool arm, wherein said ground engaging means are steerable such that the weeding apparatus may track independently of said tractor.

20. A weeding apparams according to any one of Claims 16 to 19 and coupled to a tractor and having provision for a second operator to precisely steer the tool bar within the confines of any side drift of a standard 3-point linkage.

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21. A weeding apparatus according to Claim 20 coupled to be towed by a tractor with the accommodation for the second operator comprising a seat located at the rear of the tractor and facing said apparatus.

22. A weeding apparams according to Claim 20 coupled to be pushed by a tractor with the accommodation for the second operator comprising a seat located at the front of the tractor and facing said apparatus.

23. A weeding apparams according to any one of Claims 16 to 22 wherein the drive means includes a central source of motive power coupled to a common drive shaft connected to the cutter blade assemblies.

24. A weeding apparatus according to any one of Claims 16 to 19 and including sensor means adapted to locate the correct path for the tool bar and acmate a steering mechanism to guide the tool bar along the correct path.

25. A weeding apparatus according to any one of Claims 16 to 24 wherein the cutter blade assemblies are driven out of phase to reduce the load on the power source.

26. A weeding apparatus substantially as herein described with reference to Figures 1 to 6 of the accompanying drawings.

27. A weeding apparatus substantially as herein described with reference to Figures 7 to 11 of the accompanying drawings.