AU718187B3 - A rake assembly - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A PETTY PATENT Name of Applicant(s): Actual Inventor(s): Address for Service: Invention Title: KENNETH ARTHUR HARDWICK DOUGLAS ARTHUR HARDWICK KENNETH ARTHUR HARDWICK DOUGLAS ARTHUR HARDWICK CULLEN CO., Patent Trade Mark Attorneys, 240 Queen Street, Brisbane, Qld. 4000, Australia.

A RAKE ASSEMBLY The following statement is a full description of this invention including the best method of performing it known to us.

THIS INVENTION relates to a rake assembly which can be used to clear a path or paths through surface debris on a field. In particular, the present invention is directed towards clearing a path or paths through a blanket of sugar cane trash on a cane field.

The present invention will be described with particular reference to clearing paths through a blanket of trash on a sugar cane field. However, it will be appreciated that the rake assembly may be used to clear a path through surface debris other than cane trash and no limitation is intended thereby.

Traditionally, sugar cane crops were burnt prior to harvesting.

Such burning removed the foliage from the sugar cane stalks. This was considered desirable as the presence of foliage interfered with sugar cane processing. It was therefore unnecessary to devise methods for removing the foliage before processing. However, in recent times, the practice of harvesting has moved away from burning. This recent practice has caused or resulted in the development of harvesters which are able to defoliate the cane stalks. The defoliated material, which is known as trash, is typically exhausted from the harvester. The trash is generally blown from the harvester away from the cane rows to be harvested and towards the harvested ground. This produces a substantially uniform layer of trash on the harvested ground which is known as a trash blanket When cane is harvested, the cane stem is cut close to the soil level without uprooting the sugar cane stools or clusters of stems.

Subsequent crops are obtained through germination of the stool to produce ratoons. Typically, cane fields yield up to five ratoon crops from a single planting. Good ratoon growth is important for the yield of a ratoon crop.

However, ratoon growth is inhibited by damp cool conditions. The presence of the trash blanket contributes to these undesirable conditions for ratoon growth.

A new sugar cane crop can also be obtained by destroying the existing stool, cultivating the ground and replanting. This is generally done after about four or five ratoon crops. The presence of the trash blanket interferes with cultivation of the cane field.

Because of the above difficulties, caused by the presence of the trash blanket, it is generally considered desirable to remove the trash blanket after harvest. Typically, the trash is destroyed by burning. Trash removal adds to time or labor costs and the burning creates pollution. Also, the trash blanket is a valuable source of plant nutrients and it would be desirable to be able to utilize this nutrient value for cane production. However, because of the above difficulties associated with the presence of the trash blanket, this has to date, not been possible.

It is therefore an object of the present invention to provide an assembly and method which may at least partially overcome the above disadvantages or provide the public with a useful choice.

According to a first broad from of the invention, there is provided a rake assembly adapted to be attached to and pushed or towed by a pushing or towing vehicle over a ground surface which is substantially covered with surface debris, the assembly including at least one rake unit, the at least one rake unit including a pair of finger wheel rakes which are at an angle to each other and in use, when the assembly is pushed or towed over the surface, the at least one rake unit clears a path through the surface debris by moving the debris to one or both sides of the cleared path one wheel rake moving debris to one side of the path and the other wheel rake moving debris to the other side of the path..

The rake assembly can be either pushed or towed. In one embodiment of the invention, the assembly is pushed before a vehicle such as a tractor. The tractor may also be towing a cultivator or other suitable agricultural implement. Generally, the rake assembly mounted to the front of the tractor clears one or more path to allow the cultivator or other implement to cultivate, fertilize or plant the cleared path. It can be seen that such an arrangement allows cultivation of the freshly cleared path in a single pass of the tractor.

3 According to a further broad form of the invention, there is provided a method of working an agricultural field having a layer of surface thereon, the method including mounting a rake assembly according to the first broad form of the invention to a vehicle, mounting an agricultural implement for working the field to the rear of the vehicle and driving the vehicle along the field such that the rake assembly clears at lest one path and the agricultural implement works the at least one cleared path.

The term "working the field" as used in the above embodiment, includes any form of working a field or ground surface as used in agriculture and includes planting, fertilizing, cultivating or applying pesticides or other chemicals.

The rake assembly of the present invention includes one or more rake units which can clear a path by pushing the surface debris to one side. Typically, this allows the surface debris to be pushed into rows alongside the cleared paths. In cases where the surface debris has a nutrient value, it is desirable that the debris be left in a field and not removed. This is in contrast to conventional rake assemblies which are designed to remove surface debris from a site.

The rake unit may include one or more rake members.

The rake member for use in the assembly of the invention is typically of the wheel rake type. The wheel rake is suitably rotatably mounted to a support arm at an angle to the direction of travel. When pushed or towed, the wheel rotates and pushes the raked material to one side. A particularly preferred rake member is a finger wheel rake which has fingers or tynes mounted about the wheel rim and in the present specification and claims, the term "finger wheel rake" refers to such a rake.

Typically a rake unit includes a pair of rake wheels which, when in use, one rake wheel pushes trash to the left and the other rake wheel pushes the trash to the right side in the direction of travel.

The rake assembly of the present invention can include one or more rake members. The number of rake members may depend upon the number of paths which are desired to be cleared with a single pass of the pushing or towing vehicle. It will be appreciated that the number of paths to be cleared will depend on the particular application. Typically, for use in sugar cane fields, the assembly can clear two parallel paths.

The assembly of the invention may be used to clear paths for a cultivator prior to cane replanting. Alternatively, the assembly may be used to clear trash from the stools to facilitate ratooning. Still further, the assembly may be used to clear surface debris from between the cane rows (interows) to facilitate water flow through the interows for flood irrigation.

By way of example only, the present invention will now be described with reference to the following figures in which: Figure 1 is a schematic front view of a preferred rake assembly of the present invention mounted to the front of a tractor; and, Figure 2 is a plan view of the assembly of Figure 1.

Figure 1 illustrates a preferred rake assembly 11 of the present invention mounted to a hydraulic ram 12 on the front of a tractor 13. The hydraulic ram allows the assembly to be lifted or lowered as required. The tractor 13 also has a rotary hoe (not shown) mounted to the rear.

The rake assembly has a main frame arm 15 (more easily illustrated in Figure Two pairs of opposed secondary arms 16, 17, and 18, 19 extend forward at an angle of 450 from the main frame arm 1-5. Towards the end of each secondary arm is slidably mounted a sleeve 20, 21, 22, 23.

The position of the respective sleeves on the secondary arms can be fixed by pins. To each sleeve 20, 21, 22, 23 is pivotally mounted a rake arm 24, 26, 27 by a pivot pin attached at 900 to the direction of travel, indicated by arrow A. To each rake arm is rotatably mounted a finger wheel rake 28, 29, 31. The rake wheels have curved wire fingers 32 extending from the rim.

The front left 24 and rear right 26 rake arms are parallel to main arm 15. The front right 28 and rear left 31 rake arms are at an angle of 45 to the main arm Each rake wheel is inclined at an angle of 450 to the direction of travel. The rake wheels are mounted to the rake arm such that this angle can be varied if desired. The front right 28 and the rear left 31 rake wheels are angled such that their front face faces the direction of travel. The front left 29 and rear right 30 rake wheels have their rear face directed towards the direction of travel.

When the assembly is pushed forwards, the front rake wheels 28, 29 are pushed so as to rotate in an anti-clockwise direction and discharge surface debris or cane trash to the right when viewed in the direction of travel.

The rear wheels 30, 31 counter-rotate and discharge material to the left. In this way, the pairs of front and rear wheels each clear a path behind them as the rake assembly is pushed forwards. It can be seen that the width of each cleared path can be adjusted by sliding the sleeves 20, 21, 22, 23 along the secondary arms, 16, 17, 18, 19.

The paths cleared by the rake wheels can then be cultivated by the rotary hoe which is being towed by the tractor.

When used in a cane field, an operator can cultivate either the cane row or the interow. When the cane row is cultivated, the cane stools are destroyed for replanting. If the operator chooses to destroy or cultivate the cane row, he aligns the front wheels of the tractor with the cane rows, lowers the rake assembly and drives forward. The rake assembly clears the cane rows to allow the following rotary hoe to destroy the cane stools and cultivate the ground.

The cleared, cultivated rows can then be fertilized as required.

The fertilizer can easily be spread by tynes, discs or rotary hoe without interference by residual trash. The field is then ready for replanting.

It can be seen that by pushing the trash to each side of the cleared row, the trash is left in uniform strips along the ground. The trash can then decompose to release the nutrients.

After sugar cane is planted, it is common practice to shape the cane row with a plant cane plough or "pig". This shaping covers the trash lying in the interow with soil which facilitates decomposition.

The rake assembly 11 can also be provided with a three point linkage to allow it to be mounted to the rear of a tractor. In this way, the rake assembly can be used to direct the trash from cane stools after harvest. This allows the sun to reach the stool and also minimizes water retention about the stools. Excess moisture and cooler temperatures inhibits ratooning.

It can be seen that the rake assembly of the present invention can be used to clear paths through a cane trash blanket. The cleared trash is formed into substantially uniform trash rows between the cleared rows. In the embodiment which uses pairs of counter rotating wheel rakes which transfers trash to both sides of the cleared path, the trash rows are of a substantially uniform thickness. Thus, the trash can remain in the cane field without adversely affecting ratooning, cultivation or irrigation. Considerable savings in time and costs can accordingly be made.

By using the rake assembly of the present invention, the nutrient value of the trash blanket can be retained. This can reduce the amount of chemical fertilizers applied to the field which can reduce costs still further.

For example, it is estimated that a cane trash blanket is equivalent to about 240 kg of urea per hectare. It can be seen that where the trash has been formed into uniform rows, the resultant composting or breakdown of the trash results in a substantially uniform distribution of nutrients throughout the field.

This is generally considered desirable. The uniform trash distribution can also minimize the areas in which the trash is of an excessive depth. Where this occurs, there may be insufficient aeration of the trash resulting in anaerobic decomposition of the trash as opposed to aerobic composition.

This may be undesirable.

Still further, the trash blanket can reduce water loss in a field.

Also, by being able to avoid the necessity of trash removal by burning, it is possible to harvest and replant a sugar cane crop in the same day.

It will be appreciated that various changes and modifications can be made to the invention as described and claimed without departing from the spirit and scope thereof.

Claims (3)

1. A rake assembly adapted to be attached to and pushed by pushing a vehicle over a ground surface which is substantially covered with surface debris, the assembly including a pushing arm having its trailing end adapted to be attached to a pushing vehicle and at least one finger wheel rake unit, the at least one rake unit having a pair of rake wheels which are at an angle to each other and in use when the assembly is pushed over the surface, the at least one rake unit clears a path through the surface debris by moving the debris to both sides of the cleared path, one rake wheel moving debris to one side of the path and the other rake wheel moving debris to the other side of the path.

2. The assembly of claim 1, wherein the rake wheel in a respective rake unit are staggered in the direction of travel.

3. The assembly of claim 1 or claim 2, substantially as hereinbefore described with reference to the figures. DATED this 3 rd day of February 2000 Kenneth Arthur HARDWICK and Douglas Arthur HARDWICK By their Patent Attorneys CULLEN CO.