AU711084B2 - Stubble cutting device - Google Patents

Description

Im/UU/U 1 28/5/91 Regulation 3.2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: STUBBLE CUTTING DEVICE The following statement is a full description of this invention, including the best method of performing it known to us STUBBLE CUTTING DEVICE The present invention relates, generally to agricultural equipment, and in particular, to a device for cutting stubble in fields to facilitate subsequent ploughing of the fields by tyned machinery.

In fields planted with crops such as wheat, there remains a covering of stubble on the field after harvesting of the crop. This stubble must be cleared before the field can be ploughed to enable seeding of the next crop.

It is therefore now common for stubble to be turned back into the ground rather than being burnt. This leads to a reduced need for fertilisers as plant nutrients are replaced in the soil. There is also a decrease in the amount of soil erosion as the stubble assists in holding the top soil together. Finally, humus is placed in the soil improving the fertility of the soil and thereby also reducing fertiliser requirements.

However, there is a problem in that not all plant machinery is capable of 15 working in such fields. That is, if the cut sections of stubble are too long, this *creates problems with tyned machinery in that blockages occur between the tynes, due to the long sections of stubble gathering around the leading edge of o. each tyne as it moves through the soil. It has been found for example, that in some areas cut sections of approximately 30 cm cause such problems. This 20 also leads to uneven sowing.

It has been found that if the stubble can be cut into a manageable size whereby the length of the stubble is such that tyned machinery is capable of moving through the field without substantial blockages, then the above problem is largely overcome.

25 It is therefore an object of the present invention to provide an improved device for cutting stubble.

With this in mind, there is provided a device for cutting stubble including at least one set of cutting means rotatably mounted about a first rotational axis, the at least one set of cutting means including a lower cutting means and an upper cutting means spaced apart from the lower cutting means, wherein the spacing of the cutting means is adapted for cutting the stubble into preferred lengths. Conveniently each cutting means can be a blade.

As the cutting means or blades are spaced apart, the stubble can be cut into preferred lengths of a manageable size which enables tyned machinery to move through the field without substantial blockages.

The lower and upper cutting means or blades of each blade set may be staggered such that the upper blade is located forward of the lower blade in the direction of rotation of the blade set.

In an alternative arrangement the upper and lower blade of each blade set may be at least substantially located in a common plane with said first rotational axis.

In a preferred arrangement, the lower blade may be pivotally mounted about a pivot axis at least substantially normal to the first rotational axis. A resilient means may be provided to return the lower blade to its normal working position after displacement thereof. The resilient means may be a coil spring, although other resilient means are also envisaged.

15 With the lower blade being displaceable away from the normal working position of the lower blade. This enables the lower blade to move away from its working position when the lower blade contacts a hard object such as a rock to thereby limit damage to the device.

In an alternative embodiment each cutting means can be formed from a 20 chain capable of cutting the stubble. For example, it has been found that a five inch long 3/8 high tensile chain has been suitable in some areas.

The chain has the same function as a blade and works to cut the stubble into manageable lengths. When the stalk has dried and become brittle the use of a chain can be just as effective as a blade, and has the added advantage that 25 pivoting of the lower cutting means is usually not required. Although it can be included if desired.

In a further embodiment each set of cutting means can be formed from a combination of a blade and a chain or some other cutting means.

Whilst various cutting means can be used this invention will be further described by use of cutting blades only.

The device preferably also includes suction means for lifting the stubble prior to cutting. The stubble must be substantially upright before it can be cut.

However, a large proportion of the stubble is compacted to the ground by the wheels of various farm machinery, and in particular, the harvester during harvesting. By lifting the stubble, this enables more efficient cutting of the stubble.

The device preferably includes a rotating frame rotatable about the first rotational axis. A plurality of the set of blades may be supported on the rotating frame. Each blade set preferably includes an upper blade, mounted on the rotating frame, and an arm member rotatably mounted to the rotating frame, the arm member being rotatable about said pivot axis. The lower blade is mounted to the free end of said arm member. A resilient means may be provided between the arm member and the rotating frame to maintain the arm member in a position which supports the lower blade in its normal working position, the resilient means allowing deflection of said arm member when the lower blade contacts a hard object.

15 The suction means may include at least one fan blade mounted on the 0 rotating frame. When the rotating frame is rotating, the at least one fan blade produces a suction to lift compacted stubble. A plurality of said fan blades may preferably be provided.

Preferably the suction means also includes a cowling designed to 0. 20 provide an improved uplift by controlling the direction of the air. In this regard a 0 cowling is provided which extends downwardly from the rotating frame to a depth substantially equal to, or just below the bottom edge of the at least one fan blade.

Such a cowling limits escape of air due to centrifugal forces, and 25 improves the uplift caused by the suction generated by the fan blades. Whilst it is convenient for the cowling to extend to the bottom edge of the fan blades, this depth is not essential, and the cowling may extend to a depth that is practical for its location of use.

The present invention will be more readily understood from the following description of preferred arrangements of the device as illustrated in the accompanying drawings.

It is to be appreciated that other arrangements according to the present invention are envisaged, and consequently the particularities of the accompanying drawings are not to be understood as superseding the generality of the preceding description.

For example, the cutting blades could be mounted about a rotational axis that is parallel to, rather than perpendicular to the ground. Of course in such an arrangement the suction means, if provided, would have to be rotatable about a second axis.

Figure 1 shows a section of the preferred arrangement according to the present invention, including a fan blade, and a set of blades with the lower blade pivotally mounted.

Figure 2 shows an alternative arrangement of pivotally mounting the lower blade. The upper blade has been omitted for clarity.

Figure 3 shows another alternative arrangement of pivotally mounting the lower blade. Again the upper blade has been omitted for clarity.

Figure 4 shows yet another alternative arrangement whereby the lower blade is staggered with reference to the upper blade.

Figure 5 shows a further embodiment having a cowling or skirt.

Referring now to the Figures, the stubble cutting device provides a circular frame that is capable of rotating around a central point. Note that a circular frame is not essential to the invention and a series of members extending from the central point could equally be used. Displaced around the circumference of the frame are sets of blades Each set consists of an upper blade (2a) and a lower blade although each set need not be limited to two blades, with the cutting faces of each blade facing in the direction of rotation so as to cut the stubble. Preferably the blades are connected in such a way that they can be easily replaced by the farmer. This can be achieved by having the blades (2a and 2b) attached to arm members (2c and 2d) capable of supporting each blade (2a and 2b). In such a configuration only the blades need to be replaced when required and not the whole assembly.

The lower blade (2b) is vertically displaced from the upper blade (2a) a distance to ensure that the stubble is cut into manageable lengths. Ideally, the blades can be staggered as shown in Figure 4, alternatively the blades can substantially be in the same vertical plane as shown in Figure 1. The only requirement being that each set is capable of cutting the stubble into lengths of a manageable size. The required vertical displacement will vary to suit the conditions. For example, it has been found that for areas around York, Western Australia, where the average length of the stubble after harvesting is approximately 45 cm, ideally the blades are displaced approximately 15 cm apart with the lower blade configured to cut the stubble approximately 15 cm above the ground. Such a configuration results in cut sections of approximately cm, and well below the 30 cm mark at around which length tyned machinery does not work effectively. The vertical displacement is maintained by the lower arm member (2c) being attached to a shaft extending vertically from the lower arm member (2c) towards the upper arm member (2d).

In the arrangement of Figure 4, it is preferable that the blades are staggered such that the upper blade comes into contact with the stubble first, 15 followed by the lower blade. Again this horizontal displacement may vary according to local conditions, however, it has been found that the system o achieves desirable results by having the upper blade located approximately 23 cm forward of the lower blade.

In a preferred system the shaft is supported by a sleeve which 20 allows pivotal movement about a pivot means which may extend from the sleeve generally from the opposing end to the shaft to enable the lower blade (2b) to deflect upwardly about the pivot means upon contacting a hard ""**object such as a rock. By deflecting upwardly the lower blade (2b) allows the hard object to pass under the blades, thus decreasing the likelihood of 25 breakages to the lower blade To ensure that the lower blade (2b) returns to its original position a resilient means such as a spring, is provided. The resilient means is connected from the lower blade (2b) or pivot means to a fixed point in front of this position usually on the frame The requirement being that the resilient means allows the lower blade (2b) to be deflected by hard objects, and is capable of returning the lower blade (2b) to its normal working position once the object has passed. This system works by the resilient means being stretched, however, the resilient means could also work by compression, provided it was located in a suitable position behind the pivot means It will also be appreciated by the person skilled in the art that other methods may be employed in place of the resilient means. For example, a counter weight located on the blade portion. What is important is that the deflected blade be returned to its normal operating position following deflection by a solid object. Similarly, the lower cutting means or blade could be mounted at an angle relative to the rotational axis.

In order to lift the stubble to assist the cutting process, a number of fan blades can also be displaced around the frame The fan blades are shaped and fitted in such a way as to cause a substantial updraft which causes crushed stubble to be lifted. For example, if the diameter of the rotor, or distance of the blades from the rotational axis of the stubble cutter is approximately So 1.5 metres, then the fan blades are preferably 360 mm by 130 mm.

The updraft can be further improved by providing a skirt or cowling (8) 15 which extends downwardly from the frame to the lower edge of the fan blades to thereby control the direction of the updraft. The cowling and frame could be formed from a single component. The cowling will be provided in such a way that it will not interfere with the workings of the blades or resilient means 20 The complete system can be assembled in a number of ways, such as, using a central hub with supporting members extending therefrom, rather than a circular frame Similarly the types of blades, and how they are fixed can be achieved in any number of ways. The important features are the twin set of °blades which may be in vertical alignment or alternatively staggered. It is also preferable that the lower blade is capable of deflecting away from hard objects. In a further improvement fan blades are provided to ensure the majority of the stubble is capable of being cut.

Claims (11)

1. A stubble cutting device including at least one set of cutting means rotatably mounted about a first rotational axis, the at least one set of cutting means including a lower cutting means and an upper cutting means spaced apart from the lower cutting means, wherein the spacing of the cutting means is adapted for cutting the stubble into preferred lengths, and wherein said lower cutting means is pivotally mounted.

2. A stubble cutting device as claimed in claim 1 wherein said upper cutting means and said lower cutting means are substantially located in a common plane with said first rotational axis. o

3. A stubble cutting device as claimed in claim 1 wherein said upper cutting S means is located forward of said lower cutting means relative to the direction of movement of said cutting means set.

4. A stubble cutting device as claimed in any preceding claim wherein said 9999 *••99 upper cutting means and said lower cutting means respectively include a cutting blade. A stubble cutting device as claimed in any one of claims 1 to 3 wherein said upper cutting means and said lower cutting means respectively include a length of chain.

6. A stubble cutting device as claimed in any one of claims 1 to 3 wherein said set of cutting means includes a combination of a cutting blade and a length of chain.

7. A stubble cutting device as claimed in any preceding claim wherein said lower cutting means is pivotally mounted about a pivot axis at least substantially normal to said first rotational axis. 8

8. A stubble cutting device as claimed in claim 7 including a resilient means adapted to return said lower cutting means to its normal working position after any displacement thereof.

9. A stubble cutting device as claimed in 8 wherein said resilient means includes a coil spring. A stubble cutting device as claimed in any preceding claim including a suction means, wherein said suction means includes at least one fan blade mounted on a rotating frame.

11. A stubble cutting device as claimed in claim 10 further including a cowling adapted to provide an improved uplift by controlling the direction of the air. 0. o: 9*99 t99o to o12. A stubble cutting device as claimed in claim 11 wherein said cowling extends downwardly from said rotating frame to a depth substantially equal to a bottom edge of said at least one fan blade. to

13. A stubble cutting device as claimed in any preceding claim wherein said at least one set of cutting means is located approximately 1.5 metres from said 0 first rotational axis. 9 0

14. A stubble cutting device as claimed in any one of claims 10 to 13 wherein said at least one fan blade is approximately 360 mm by 130 mm. A stubble cutting device as herein before described with reference to any one of the embodiments shown in the accompanying drawings. DATED this 20th day of July 1999 JOSEPH PATRICK NAUGHTON WATERMARK PATENT TRADEMARK ATTORNEYS 4TH FLOOR, "DURACK CENTRE" 263 ADELAIDE TERRACE PERTH W.A. 6000 AUSTRALIA S a. a o. a a *o