AU2006203367A1 - Tilling Apparatus - Google Patents

Description

Field of the Invention The present invention relates generally to tilling apparatus of the type which are secured relative to a prime mover such as a tractor and which are able to till ground while the prime mover is in motion. In particular, the present invention relates to ground-tilling apparatus of the aforementioned type which are able to till to a substantially consistent depth despite undulations and other variations in the surface of the ground.

Although the present invention will be described with particular reference to agricultural ground-tilling apparatus it will be appreciated that this is by way of example only and that the present invention may be incorporated into other types of tilling apparatus such as, for example, non-agricultural tilling apparatus.

Brief Discussion of the Prior Art Various types of ground-tilling apparatus are used to till agricultural land.

The two types of ground-tilling apparatus which are most commonly used in Australian agriculture are fixed-tine and parallelogram tilling apparatus. Both types of tilling apparatus are normally secured to a tool bar which is coupled to a prime mover, and both types of tilling apparatus normally have one or more tines or other tilling tools which are able to penetrate the ground to be tilled to a range of depths so that the tines or other tilling tools are able to till the ground while the tractor or other prime mover is in motion.

The tines of a fixed-tine tilling apparatus are usually secured relative to a toolbar so that there can be little if any relative movement between the tines and the toolbar. Consequently, the depth to which the tines of a fixed-tine apparatus penetrate the ground is mainly dependent on the position of the ground surface relative to the tool bar to which the tilling apparatus is secured. If the ground which is being tilled is substantially flat, the position of the tool bar relative to the ground surface will generally remain substantially constant so that the fixed-tine tilling apparatus will till the ground to a substantially constant depth. However, if the ground is uneven and includes surface variations such as undulations, the position of the tool bar relative to the ground surface will vary and this wall cause variations in the depth to which the fixed-tine tilling apparatus tills the ground.

In contrast to fixed-tine tilling apparatus, the depth to which a parallelogram tilling apparatus tills the ground is not nearly as strongly influenced by the position of the ground surface relative to the tool bar to which the parallelogram tilling apparatus is secured. This is because, unlike a fixed-tine tilling apparatus, a parallelogram tilling apparatus is free to move through a predetermined range of movement relative to the tool bar which it is secured to. This controlled range of movement is provided by parallel arms of the apparatus which are hinged relative to the toolbar and the tines or other tilling tools of the apparatus so that the arms are able to pivot relative to the bar and the tines and thereby cause the tines to move relative to the toolbar so as to compensate for variations in the position of the toolbar relative to the ground surface.

Fixed-tine tilling apparatus are suitable for use in tilling operations where tilling depth control is not particularly critical such as primary tilling operations involving the break-up of stubble after harvest where the depth of ground penetration of the tilling tool can be anywhere from 100 mm to 250 mm. Where the depth of penetration of the tilling tool is relatively deep such as in primary tilling of the aforementioned type, slight variations in the depth of penetration of the tilling tool are not critical because the tilling tool will still remove some topsoil and therefore partially complete the tilling operation.

Some tilling operations, such as those associated with the planting of some types of seeds, require very stringent control of the tilling depth. For example, when tilling ground in preparation for the planting of seeds such as millet or sorghum seeds, it is important that the tilling depth be within a certain range as millet and sorghum seeds can be spoiled or have a low germination rate if they are planted too deep or too shallow.

To achieve greater depth control, parallelogram tilling apparatus are used in preference to fixed-tine tilling apparatus. The tilling depth of parallelogram tilling apparatus is controlled by a depth-setting device such as a wheel or coulter disc which improves the depth control of the apparatus to a point where variations between the actual tilling depth achieved by using the apparatus and the desired tilling depth are almost negligible.

With profit margins in agriculture ever decreasing, and a significant shift in agriculture towards trying to improve moisture retention and increased utilisation, seed depth and placement has become a very important consideration for a majority of broad acre farming operations, and has significantly increased the demand for parallelogram tilling apparatus.

There are a variety of different types of parallelogram tilling apparatus on the market today, each having its own particular advantages and disadvantages.

Although the different types of parallelogram tilling apparatus are designed to perform similar tasks and meet similar objectives, they do so in different ways.

Janke® markets a parallelogram planting apparatus that includes a rubberised drum and coulter arrangement for depth control, and a plurality of springs to create various forces and pressures such as a down-force for pressing a tilling tool of the apparatus down into the ground, and a breakout pressure. The apparatus is very strongly built with large pivot pins and pivot bearing surfaces making the unit very long lasting and maintenance free. The coulter disc of the apparatus is able to cut through the heaviest of trashes so that the apparatus can easily be used for zero or minimum tillage operations.

The main problems with the Janke® apparatus from the point of view of a manufacturer is that the apparatus has a large number of components and requires a significant amount of labour to build which means that the apparatus has a high cost in comparison to fixed tine tilling apparatus. Also, because the apparatus has two springs for producing the down-force, and another two springs for producing the breakout pressure, this alone adds a significant amount to the cost of the apparatus even without taking the other factors into account.

From the point of view of a user, the Janke® apparatus performs well in most conditions but is limited in the types of tilling tools that it can use. At present, the apparatus is only able to use tines even though some users would like to be able to use other types of tilling tools such as a double-disc opener so as to increase their planting configuration options.

There are also problems associated with the down-force producing mechanism of the Janke® apparatus. The side springs of the apparatus which exert down-force on the coulter disc of the apparatus are renowned for breaking under conditions where the apparatus should perform satisfactorily. Moreover, the geometry of the side springs creates problems of variable down-force on the coulter disc with variations of up to 32% having been recorded in normal operating conditions. Although the apparatus has a swivel mechanism which allows the apparatus to pivot from side to side relative to the bar to assist the apparatus in taking tight corners and negotiating obstacles, the adjustment mechanism of the swivel mechanism is very difficult to adjust especially considering that if a plurality of planting apparatus are used, the adjustment mechanism of each individual apparatus would need to be adjusted one at a time.

Another parallelogram tilling apparatus which is currently available on the market is the Simplicity® Striker T M apparatus which, similarly to the Janke® apparatus, includes a coulter disc for depth control, but which, in contrast to the Janke® apparatus, has a walking beam system that is limited by a hydraulic cylinder to control down-force and breakout pressure. The design of the Simplicity® apparatus is very simple and has the advantage of independent movement between the coulter disc and the tine as a result of the simple walking beam design. From a manufacturing point of view, the Simplicity® apparatus is very simple to build and assemble owing to the apparatus having a relatively small number of components, and because it has components which perform a number of functions.

Although the Simplicity® apparatus has a simple design, the apparatus appears to be less robust compared to other parallelogram tilling apparatus on the market. Also, unlike the Janke® apparatus, the Simplicity® apparatus does not include a swivel mechanism. The Simplicity® apparatus appears to have the ability to handle stubble in a similar manner to the Janke® apparatus due to the presence of the coulter disc, but the travel of the coulter disc of the Simplicity® apparatus appears to be very limited which could prevent the coulter disc from clearing large obstacles.

The down-force produced by the Simplicity® apparatus seems to be quite variable due to the change of the angle of the hydraulic cylinder of the apparatus through the restricted range of motion thereof.

Yet another existing parallelogram tilling apparatus is the Excel® Agriculture Stubble WarriorTM which is somewhat similar to the Janke® apparatus.

The main difference between the Excel® and Janke® apparatus is that the Excel® apparatus is able to use a coulter disc, a rubber tyred wheel, or a double-disc opener to set the tilling depth. Also, the Excel® apparatus is able to incorporate a tine into the Nparallelogram of the apparatus together with a double-disc opener. Apart from these tbdifferences, the main advantage of the Excel® apparatus is that it is very simple and that it seems to be well built particularly in the areas of the apparatus that are prone to high stresses and strains.

Like the Janke® apparatus, the down-force and breakout pressure of the Excel® apparatus are produced with the aid of a number of springs. The down-force ¢€3 Cc spring of the Excel@ apparatus appears to produce a somewhat constant down-force but appears to be very difficult to adjust. The Excel® apparatus is also very

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cumbersome owing to the large tine head assembly of the apparatus and the fact that 1 0 the tine head assembly connects to the rest of the apparatus a long way back from the bar mount which is used to mount the apparatus to a toolbar of a prime mover or trailer. Another disadvantage of the Excel® apparatus is that, in contrast to the Janke® apparatus, it is not able to swivel relative to the toolbar to which it is mounted so that it is not as suitable for use in situations where tight corners are a problem.

Another parallelogram type tilling apparatus which is currently available is the DBS® precision seeder apparatus. The DBS® apparatus utilises a three slot system involving deep cultivation by a vertical blade followed by a closing tool which acts in a parallelogram configuration partially independent to the opening blade or tine. The parallel component of the apparatus deposits seed and fertiliser in the trench created by the tine. The apparatus has a hydraulic breakout on the tine, and a springloaded down-force on the closing parallelogram. The reason that the parallelogram is not fully independent of the tine is that the parallelogram is controlled by a trailing press-wheel. As the tine rips deeper, higher soil disturbance is created which causes the parallelogram to sink further into the soil and thereby significantly change the depth of the planted seed.

In contrast to the Janke®, Simplicity®, and Excel® apparatus, the DBS® apparatus is not a ground-following tilling apparatus as the depth of penetration of the tine of the DBS® apparatus is totally dependent on the height relative to the ground of the toolbar which the apparatus is secured to. This further affects the amount of soil disturbance produced by the apparatus and the penetration depth of the tine which both affect the seed depth.

The limited features of the DBS® apparatus means that the apparatus requires less moving parts compared to other more sophisticated apparatus, and this makes the DBS® apparatus simpler to manufacture compared to other apparatus.

However, unlike other more sophisticated tilling apparatus, the DBS® apparatus has very limited depth control.

It would be desirable to have a ground-tilling apparatus which has at least some of the advantages of the various prior art parallelogram type ground-tilling apparatus mentioned above, but which at the same time omits at least some of their disadvantages.

Summary of the Invention It is an object of the present invention to overcome, or at least ameliorate, one or more of the deficiencies of the prior art mentioned above, or to provide the consumer with a useful or commercial choice.

Other objects and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying illustrations, wherein, by way of illustration and example, a preferred embodiment of the present invention is disclosed.

According to a broad aspect of the present invention there is provided a ground-tilling apparatus comprising a front member, a rear member, at least one lower arm extending between and hinged relative to both the front and rear members, at least one upper arm extending between and hinged relative to both the front and rear members, wherein the front and rear members are able to pivot relative to the at least one lower arm and the at least one upper arm such that the rear member is thereby lowered or raised relative to the front member, a coupling member hinged relative to the at least one lower arm, a ground-engagable tilling tool secured relative to the coupling member, an extendable member extending between and hinged relative to the at least one upper arm and the coupling member such that the tilling tool is able to be lowered and raised by extending and retracting the extendable member, and a ground-following member coupled relative to the rear member such that the ground-following member is able to cause the rear member to be raised and lowered relative to the front member to thereby maintain the tilling tool at a substantially constant ground-tilling depth.

In contrast to the prior art apparatus which include a plurality of mechanisms for producing down-force and breakout pressure, and for lifting and lowering the tilling tool, the ground-tilling apparatus according to the present invention is able to perform all of these functions merely by appropriately extending and retracting the extendable member thereof. This greatly simplifies the overall design, manufacture and maintenance of the ground-tilling apparatus compared to other known depthcontrollable ground-tilling apparatus.

The ground-tilling apparatus may or may not be an agricultural groundtilling apparatus which is suitable for agricultural applications such as the tilling or ploughing of agricultural fields. However, in a preferred form, the ground-tilling apparatus is an agricultural ground-tilling apparatus which is specifically for use in agricultural applications.

The ground-tilling apparatus may have any suitable dimensions and have any suitable weight. It is preferred that the dimensions and weight of the apparatus are such that the apparatus is able to be towed by a prime mover such as a tractor either alone or in combination with other ground-tilling apparatus of the same or different type, or apparatus which are not ground-tilling apparatus.

In a preferred form, the dimensions of the ground-tilling apparatus are such that when a plurality of them are towed by a prime mover such that they are laterally spaced from each other, they are able to operate effectively while spaced 300 mm or more apart. In a particular preferred form, the dimensions of the ground-tilling apparatus are such that they are able to operate effectively while spaced at least 813 mm apart.

In a preferred form, the ground-tilling apparatus weighs between 50 kg to 150 kg. In a particular preferred form, the ground-tilling apparatus weighs approximately 85 kg.

The various components of the ground-tilling apparatus may be fabricated from any suitable material or combination of materials using any suitable fabrication process or processes.

The front member of the ground-tilling apparatus may be of any suitable size and shape. In a particular preferred form, the front member includes a pair of upstanding and parallel sub-members which are laterally separated from each other Nand which are joined by a pair of laterally separated joining sub-members. Each one b of the parallel sub-members preferably has a respective opening located adjacent a respective end thereof for receiving a pivot pin.

The rear member of the tilling apparatus may be of any suitable size and shape. In a particular preferred form, the rear member includes a pair of upstanding and parallel sub-members which are laterally separated from each other and which are joined by a joining sub-member. Each one of the parallel sub-members preferably has a respective opening located adjacent a respective end thereof for receiving a Ipivot pin.

The at least one lower arm may be of any suitable size and shape.

Preferably, the at least one lower arm is an elongate member. In a particular preferred form, the tilling apparatus includes a pair of elongate and parallel lower arms that are joined together by a joining member. Each lower arm preferably has a respective opening located adjacent a respective end thereof for receiving a pivot pin.

The at least one upper arm may be of any suitable size and shape.

Preferably, the at least one upper arm is an elongate member. In a particular preferred form, the tilling apparatus includes a pair of elongate and parallel upper arms. Each upper arm preferably has a respective opening located adjacent a respective end thereof for receiving a pivot pin. It is preferred that each upper arm has a plurality of holding slots for hinging the extendable member relative to the upper arms.

The lower and upper arms may or may not be parallel with respect to each other. In a preferred form however, the lower and upper arms are substantially parallel with respect to each other and are able to pivot relative to the front and rear members such that they remain parallel with respect to each other.

The lower and upper arms may be hinged relative to the front and rear members in any suitable manner or combination of manners. In a preferred form, the lower and upper arms are hinged relative to the front and rear members by pivot pins.

In a particular preferred form, a single pivot pin hinges two lower arms relative to the front member, and a single pivot pin hinges the lower arms relative to the rear member. Also, in the preferred form of the tilling apparatus, a single pivot pin hinges two upper arms relative to the front member, and a respective pivot pin hinges each upper arm relative to the rear member.

The coupling member may be of any suitable size and shape. In a preferred form, the coupling member is generally Y-shaped and has a first branch hinged relative to the at least one lower arm, and a second branch hinged relative to the extendable member. The coupling member may be hinged relative to the at least one lower arm and the extendable member in any suitable manner or combination of manners. In a preferred form, the coupling member is hinged relative to the at least one lower arm by a pivot pin which may or may not also pivot the at least one lower arm relative to the rear member. The coupling member is preferably hinged relative to the extendable member by a pivot pin.

The ground-engagable tilling tool may be any suitable tilling tool or combination of tilling tools and may be of any suitable size and shape. In one preferred form, the tilling tool is in the form of a tine. In another preferred form, the tilling tool is in the form of a double-disc tilling tool. In yet another preferred form, the tilling tool is in the form of a Wiese knife. It is preferred that the tilling tool is aligned with the ground-following member.

The extendable member may be of any suitable type and may be of any suitable size and shape. In a preferred form, the extendable member is in the form of a hydraulic or pneumatic cylinder including a cylinder portion and a ram portion which is extendable and retractable with respect to the cylinder portion by varying the pressure of a hydraulic fluid or air in the cylinder portion. If the extendable member is in the form of a hydraulic or pneumatic cylinder, it is preferred that the cylinder portion of the hydraulic or pneumatic cylinder is hinged relative to the at least one upper arm, and that the ram portion of the hydraulic or pneumatic cylinder is hinged relative to the coupling member.

The extendable member may be hinged relative to the at least one upper arm in any suitable manner or combination of manners. In a preferred form, the extendable member includes a pair of pivot pins secured thereto and extending therefrom that are each received by a respective holding slot in the upper arm or arms such that the extendable member is thereby able to pivot relative to the upper arm or arms.

It is preferred that the tilling tool is lowered and raised by respectively extending and retracting the extendable member.

The location at which the extendable member is able to pivot relative to the at least one upper arm is preferably able to be adjusted so that the maximum downforce which can be exerted on the tilling tool by the extendable member can be varied by adjusting the location of the pivot. It is preferred that the location at which the extendable member is able to pivot relative to the at least one upper arm is able to be adjusted in discrete increments. The extendable member is preferably pivoted relative to the at least one upper arm by a pair of pivot pins which extend from the extendable member, and which are each received by a selected respective one of a substantially vertical array of holding slots of the upper arm or arms. Preferably, the maximum down-force which is able to be exerted by the extendable member on the tilling tool decreases the higher the holding slot which receives a pivot pin of the extendable member is. In a particular preferred form, when the pivot pins are received by the uppermost holding slots of the array, extending and retracting the extendable member causes the coupling member to pivot relative to the at least one lower arm such that the tilling tool moves in a direction which is opposite to the direction it would move if the pivot pins were received by any of the lower holding slots. Preferably, when the pivot pins are received by the uppermost holding slots of the array of holding slots, extending and retracting the extendable member causes the coupling member to pivot relative to the at least one lower arm such that the tilling tool is respectively lifted and lowered.

The ground-following member may be of any suitable type and may be of any suitable size and shape. Also, the ground-following member may comprise one or more ground-following members. The ground-following member may, for example, be a coulter disc, a wheel, or a combination of wheels and a double-disc tilling tool. The ground-following member is preferably secured relative to a leg member, and the leg member is preferably secured relative to the rear member of the tilling apparatus.

A swivel member is preferably hinged relative to the front member such that the tilling apparatus is able to pivot from side to side relative to the swivel member. It is preferred that the swivel member is hinged relative to the front member by a vertical pivot pin. Preferably, the amount by which the apparatus is able to pivot from side to side relative to the swivel member is able to be adjusted.

Preferably, the tilling apparatus includes at least one clamp member for clamping the swivel member to a toolbar of a prime mover such as a tractor, or a toolbar of a trailer. The clamp members are preferably secured to the swivel member by one or more nut and bolt assemblies.

The tilling apparatus may include a press-wheel which trails the tilling tool such that the press-wheel is able to press down on the ground tilled by the tilling tool and thereby close a slit or trench formed in the ground by the tilling tool. The press-

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wheel is preferably aligned with the tilling tool and the ground-following member. In

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Sa preferred form, the press-wheel is secured relative to a leg member, and the leg

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10 member is preferably hinged relative to the rear member. The leg member is preferably downwardly biased by a coil spring.

The extendable member is preferably able to lift and hold the tilling tool and the ground-following member above the ground so that neither the tool nor the member are able to disturb the ground. In particular, the extendable member may be able to automatically lift and hold the tilling tool and the ground-following member above the ground when being transported or when otherwise not required for tilling such as in some planting operations.

Brief Description of the Illustrations In order that the invention may be more fully understood and put into practice, a preferred embodiment thereof will now be described with reference to the accompanying illustrations, in which: Figure 1 is a perspective view of a tilling apparatus according to a first preferred embodiment of the present invention; Figure 2 is an enlarged perspective view of a portion of the tilling apparatus depicted in figure 1 without the press-wheel assembly and coupling member; Figure 3 is a perspective view of a tilling apparatus according to a second preferred embodiment of the present invention; and Figure 4 is a perspective view of a tilling apparatus according to a third preferred embodiment of the present invention.

(Detailed Description of the Illustrations Referring to figures 1 and 2, a tilling apparatus 20 according to a first preferred embodiment of the present invention includes a front member 21 comprising a pair of laterally separated and upstanding parallel sub-members 22 which are joined together by joining sub-members 23, and a rear member 24 comprising a pair of laterally separated and upstanding parallel sub-members which are joined together by a perpendicular joining sub-member 26.

A pair of laterally separated and parallel elongate lower arms 27 extends between the front member 21 and the rear member 24. The lower arms 27 are joined 10 together by a joining member 28. The lower arms 27 are hinged at one end to a lower end of the front member 21 by a pivot pin 29, and at an opposite end to the lower end of the rear member 24 by a pivot pin 30 so that the lowers arms 27 are able to pivot relative to the front member 21 and the rear member 24.

A pair of laterally separated and parallel elongate upper arms 31 extends between the front member 21 and the rear member 24. The upper arms 31 are hinged at one end to an upper end of the front member 21 by a pivot pin 32. The other end of one of the upper arms 31 is hinged to an upper end of one of the sub-members 25 of the rear member 24 by a pivot pin 33, and the other end of the other upper arm 31 is hinged to an upper end of the other sub-member 25 of the rear member 24 by a pivot pin which is separate from the pivot pin 33.

The upper arms 31 are parallel with respect to the lower arms 27 and are able to pivot relative to the front member 21 and the rear member 24 in a similar manner to the lower arms 27. When the lower and upper arms 27, 31 pivot relative to the front and rear members 21, 24, the lower arms 27 and the upper arms 31 remain parallel to each other, and the rear member 24 is raised and lowered with respect to the front member 21.

A swivel member 34 is hinged relative to the front member 21 by a vertical pivot pin 35 which is secured relative to the joining sub-members 23 of the front member 21 by nuts 36 such that the swivel member 34 is able to pivot from side-toside relative to the front member 21 as well as the rear member 24 and the arms 27, 31.

The swivel member 34 is able to be clamped to the toolbar of a prime mover Nsuch as a tractor, or the toolbar of a trailer by a pair of clamping members 37 that are tsecured to the swivel member 34 by a plurality of nut and bolt assemblies 38.

A generally Y-shaped coupling member 39 is hinged relative to the lower arms 27 of the apparatus 20 by the pivot pin 30 so that the coupling member 39 is able to pivot relative to the lower arms 27.

A ground-engagable tilling tool in the form of a tine 40 is secured relative to a lower end of the coupling member 39.

An extendable member in the form of a hydraulic cylinder 41 is located Ibetween the upper arms 31 and extends from the upper arms 31 to the coupling member 39. Hydraulic cylinder 41 includes a cylinder 42 which is hinged relative to the upper arms 31 by a pair of pivot pins which extend outwardly from opposite sides of the cylinder 42 and which are each received in one of the holding slots 43 of a respective adjacent upper arm 31. Hydraulic cylinder 41 also includes a ram 44 which is able to be extended and retracted relative to the cylinder 42 by varying the pressure of a hydraulic fluid in the cylinder 42, and which is hinged relative to the coupling member 39 by a pivot pin 45. The coupling member 39 is able to be pivoted relative to the lower arms 27 by extending and retracting the ram 44 of the hydraulic cylinder 41 relative to the cylinder 42 thereof so as to thereby lower and raise the tilling tool 40 relative to the ground.

Apparatus 20 also includes a ground-following member in the form of a coulter disc 46 which is journaled to an axle 47 and which is aligned with the tine Axle 47 is secured to a leg member 48 which is detachably secured relative to the rear member 24 such that the ground-following member 46 is able to cause the rear member 24 to be raised and lowered relative to the front member 21 such that the tine 40 is thereby able to be maintained at a substantially constant tilling depth. In particular, the leg member 48 is secured to a welded box-shaped adapter with a pin and three set-screws to locate and hold the leg member 48 in place. The adapter is secured to the rear member 24.

A press-wheel 49 is journaled to an axle 50 which is secured to the end of a leg member 51. Leg member 51 is hinged relative to the rear member 24 by the pivot pin 30 so that the press-wheel 49 is able to be raised and lowered relative to the rear member 24. A bracket member 53 is secured to and extends upwardly from the leg member 51, and a connecting rod 54 extends between and is secured to the bracket member 53 and a projecting portion 55 which extends from the rear member 24. The connecting rod 54 extends through a compressible coil spring 56 such that the spring 56 is biased against upward movement of the press-wheel 49 relative to the rear member 24. The press-wheel 49 is aligned with both the tine 40 and the coulter disc 46. The press-wheel 49 functions to press against the ground over which the coulter disc 46 and tine 40 pass so as to thereby close the slit or trench in the ground which is formed by the coulter disc 46 and the tine The hydraulic cylinder 41 is able to be selectively operated to lower the tine 40 into the ground to the desired depth, and to raise the tine 40 to such an extent that it is lifted clear of the ground. The down-force and breakout pressures which the tine is subjected to are largely generated or produced by the hydraulic cylinder 41. The maximum down-force and breakout pressures which the tine 40 is able to be subjected to can be varied by inserting the pivot pins of the cylinder 42 of the hydraulic cylinder 41 into lower or higher holding slots 43 of the upper arms 31. The higher the slots 43 that the pivot pins of the cylinder 42 are inserted into, the lower the maximum downforce which the cylinder 41 can subject the tine 40 to, and vice versa.

If the pivot pins of the cylinder 42 of the hydraulic cylinder 41 are inserted into any of the holding slots 43 apart from the uppermost slots 43, the geometry of the apparatus 20 is such that extension of the ram 44 of the cylinder 41 will cause the tine to be lowered relative to the rear member 24. If the pivot pins of the cylinder 42 are inserted into the uppermost holding slots 43, the geometry of the apparatus 20 is such that extension of the ram 44 of the cylinder 41 will cause the tine 40 to be raised relative to the rear member 24 to such an extent that the tine 40 is lifted and held above the ground. If a plurality of apparatus 20 are secured relative to a toolbar and it is only desired to use every second (say) apparatus 20, the feature just described enables the tines 40 of the apparatus 20 which are not used to be readily lifted clear of the ground.

The hydraulic cylinder 41 is able to exert a relatively constant down-force to the tilling tool 40 even while the parallelogram formed by the front member 21, rear member, lower arms 27, and upper arms 31 is moving through a predefined range of motion. This means that the apparatus 20 is able to till all of the ground of a field to a substantially uniform depth.

It has been found with the apparatus 20 that for various breakout pressures ranging from 350 lb to 850 Ib, when the angle of the coupling member 39 varies from its down position by 00 to 400, the down-force of the tilling tool 40 varies by less than 7%.

The hydraulic cylinder 41 is able to force the tilling tool 40 into the ground from a position where it is initially above the ground, and is able to lift the tilling tool above the ground so that it is unable to disturb the ground.

The breakout angle of the apparatus 20 has been limited to 200 (this contrasts with a standard angle of 50') so that the apparatus 20 is able to satisfactorily fit between a 813 mm bar spacing. This was partly achieved by reducing the size of the press-wheel 49 and the components securing the press-wheel 49 to the rear member 24.

The breakout pressure of the apparatus 20 is adjustable up to 455 kg. This is achieved by utilising a 2" bore diameter hydraulic cylinder 41 operating at a system pressure of 1200 psi. This pressure is produced by a variable pressure accumulator similarly to other hydraulic systems which are available.

Apparatus 20 is designed to fit on a 30" underframe machine that is more than suitable for trash clearance, and when combined with the coulter arrangement and the high location of the main moving components, the apparatus 20 is suitable for maximum trash flow throughout the entire machine.

By utilising 1" and main pivot pins and very heavy duty long lasting glass injected fibre bushes, the apparatus 20 has a long working life and requires relatively little maintenance.

The amount by which the swivel member 34 is able to pivot relative to the front member 21 is able to be varied by a respective adjusting bolt 57 which is screwed into a respective threaded opening in each sub-member 22 of the front member 21 such that the threaded portion of each bolt is able to contact the swivel member 34 and thereby limit the pivoting movement thereof.

Figure 3 depicts a tilling apparatus 60 according to a second preferred embodiment of the present invention. Apparatus 60 is identical to the apparatus except that the apparatus 60 does not include the press-wheel 49 and related components which secure the press-wheel 49 to the rear member 24 and coupling member 39 of the apparatus 20. Moreover, apparatus 60 has a double-disc 61 groundengagable tilling tool secured to the coupling member 39 rather than the tine 40 of the apparatus 20. The double-disc 61 is aligned with the coulter disc 46.

Figure 4 depicts a tilling apparatus 70 according to a third preferred embodiment of the present invention. Apparatus 70 is identical to the apparatus except that the apparatus 70 has a pair of rubberised depth-setting wheels 71 and a double-disc 72 ground-engagable tilling tool in place of the coulter disc 46 of the apparatus 20. In addition, apparatus 70 has a Wiese knife 73 secured to the coupling member 39 rather than the tine 40 of the apparatus 20. Wiese knife 73 is a special type of tine arrangement which is adapted to insert fertiliser separately from seed in a single-pass planting operation.

Throughout the specification and the claims, unless the context requires otherwise, the term "comprise", or variations such as "comprises" or "comprising", will be understood to apply the inclusion of the stated integer or group of integers but not the exclusion of any other integer or group of integers.

Throughout the specification and claims, unless the context requires otherwise, the term "substantially" or "about" will be understood to not be limited to the value for the range qualified by the terms.

It will be appreciated by those skilled in the art that variations and modifications to the invention described herein will be apparent without departing from the spirit and scope thereof. The variations and modifications as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth.

It will be clearly understood that, if a prior art publication is referred to herein, that reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

Claims (15)

1. 2. The tilling apparatus of claim 1, wherein the coupling member is generally Y-shaped and includes a first branch hinged relative to the at least one lower arm, and a second branch hinged relative to the extendable member.
2. 3. The tilling apparatus of claim 1 or claim 2, wherein the ground-engagable tilling tool is a tine.
3. 4. The tilling apparatus of claim 1 or claim 2, wherein the ground-engagable tilling tool is a double-disc tilling tool. The tilling apparatus of claim 1 or claim 2, wherein the ground-engagable tilling tool is a Wiese knife.
4. 6. The tilling apparatus of any one of the preceding claims, wherein the extendable member is a hydraulic or pneumatic cylinder and includes a cylinder portion and a ram portion which is able to be extended and retracted relative to the cylinder portion.
5. 7. The tilling apparatus of claim 6, wherein the cylinder portion is hinged relative to the at least one upper arm, and the ram portion is hinged relative to the coupling member.
6. 8. The tilling apparatus of any one of the preceding claims, wherein the extendable member includes at least one pivot pin, and the at least one upper arm includes at least one holding slot for receiving the at least one pivot pin such that the extendable member is able to pivot relative to the at least one upper arm.
7. 9. The tilling apparatus of claim 8, wherein the at least one upper arm includes a plurality of holding slots. The tilling apparatus of claim 9, wherein the plurality of holding slots are arranged in a substantially vertical array.
8. 11. The tilling apparatus of any one of the preceding claims, wherein the ground- following member is a coulter disc.
9. 12. The tilling apparatus of any one of claims 1 to 10, wherein the ground- following member is a wheel.
10. 13. The tilling apparatus of any one of claims 1 to 10, wherein the ground- following member includes at least one wheel and a double-disc tilling tool.
11. 14. The tilling apparatus of any one of the preceding claims, wherein the ground- following member is secured relative to a leg member which is secured relative to the rear member. The tilling apparatus of any one of the preceding claims, wherein the apparatus further comprises a swivel member hinged relative to the front member.
12. 16. The tilling apparatus of claim 15, wherein the apparatus further comprises at least one clamp member for clamping the swivel member to a toolbar.
13. 17. The tilling apparatus of any one of the preceding claims, wherein the apparatus further comprises a press-wheel secured relative to the rear member.
14. 18. The tilling apparatus of any one of the preceding claims, wherein the extendable member is operable to cause the tilling tool to be lifted and held above the ground.
15. 19. The tilling apparatus of any one of the preceding claims, wherein the tilling tool is able to be lowered and raised by respectively extending and retracting the extendable member. A tilling apparatus substantially as herein described with reference to figures 1 and 2, or figure 3, or figure 4 of the illustrations. DATED this 4 t h day of August 2006 LIMTHONO PTY. LTD. 002 208 826) PRIME GRAIN PTY. LTD. 002 264 799) By their Patent Attorneys CULLEN CO.