Great Western Corporation Pty Ltd v Grove Hill Pty Ltd
[2001] FCA 423
At a glance
Source factsCourt
Federal Court of Australia
Decision date
2001-04-17
Before
Kiefel J
Source
Original judgment source is linked above.
Judgment (27 paragraphs)
REASONS FOR JUDGMENT 1 On 15 May 1997 the applicant Great Western Corporation Pty Ltd was granted Australian Petty Patent No 678130 for an invention entitled "Improvements in or in relation to a Row Cultivator". The provisional application was filed on 22 December 1993 ("the priority date"). On 26 August 1999 it was granted Australian Patent No 705201 ("the standard patent"). The patent was now entitled "A Tool for a Row Cultivator". The inventor named on the patents was Mr Peter Mansur. The invention was and is marketed as the "Cleansweep" product. 2 Mr Mansur's family were seed crop farmers in the United States of America and he has been involved in cotton farming in Australia. He has experience in row cropping and row cultivation. He and other members of his family have been involved in the development of farming equipment for some time. 3 Row cropping refers to plants grown in rows which are wide enough to allow a tractor to drive through. The space between the rows is known as a furrow. The land may be flat between the plant beds, or hills, or may contain channels, in the case of irrigated land. Whilst there are a number of steps in the production of crops grown in rows, Mr Mansur lists seven as usual. Row cultivation (or "inter row cultivation" as it is also called) refers primarily to the killing of weeds in the furrows between rows of plants after planting. It can also be utilised for the aeration of the soil or warming the soil for seedlings prior to planting. It applies to the cultivation of both flat beds and grooved furrows. 4 Row cultivation, in the sense of weed eradication, was achieved by using a series of tools which were pulled through each furrow. The tools used included, in sequence, two discs, two knives and an "Alabama", a shovel-like tool. The discs would break up the soil and the knives would follow and cut the weeds. This was referred to by the applicant's witnesses as a "traditional rig" or set of tools. Extra knives might also be added. It was accepted by most witnesses that these tools and their combination were commonly employed, although farmers could be expected to use any number of combinations, and a lesser number of tools might be used in narrower furrows. The basic premise remained. General use prior to the invention commonly involved a number of tools on a number of tool-carrying shanks. 5 A "row cultivator" refers to the equipment used in row crop cultivation and comprises both the tool-carrying system and the tools attached to it. It may be a number of transverse tool bars with tools fixedly mounted to each tool bar, or a transverse tool bar with tools mounted onto a parallelogram arrangement, which provides for independent height adjustment. 6 Generally speaking, tools in common use in row cultivation before the priority date included sweeps and the Alabamas mentioned, although they were not utilised at the front of a traditional rig; cutting knives and friction trip assemblies. The latter refers to a mechanism which tilts on a centre pivot when the front of the tool to which it is attached hits an obstruction in the soil. The extent to which combinations of the tools were employed is a matter taken up by the respondent in connection with a number of issues. 7 The patents explain some of the problems associated with row cultivation: "One disadvantage arises where cutter blades are employed behind a tool. Typical tooling for cultivating row crops consists of five vertical shank assemblies per row of crop with a tool comprising either "L" shaped knives or a single disc attached to the end of the shank. Each tool's position can be independently adjusted vertically and horizontally. The main problems with this type of arrangement are:- (i) the difficulty in adjusting the shank assemblies; and (ii) the narrow knives or discs allow weeds to bend around the tooling if the weed is not struck "dead-centre. The present cutter blade arrangements are inefficient." 8 An additional disadvantage is identified in the standard patent, but it is not presently relevant. Although there was much evidence put forward by the respondent to show that the difficulties in the "traditional rig" were overstated, the evidence generally supported the problems identified. The fact that some farmers might not all be as efficient or competent as those teaching in the area would not seem to detract from this. 9 The specification states that those disadvantages are sought to be alleviated: "…by providing a row cultivator having a transverse tool bar and a plurality of tool carrying shanks mounted on and projecting downwardly from the tool bar, each shank having a pair of plates mounted to the shank on opposite sides of the shank and forming a lower shank section, the lower shank section having a forwardly projecting portion fitted with a leading blade and a pair of rearward cutting blade attachment means having respective cutting blades attached thereto so as to be spaced rearwardly from and separate of the leading blade, the leading blade being followed by the pair of cutting blades, the cutting blades being adapted to travel just below soil level to sever weeds on either side of the leading blade, the cutting blades having respective leading edges diverging rearwardly and outwardly on opposite sides of the leading blade." 10 The preferred embodiment is described: "The tool preferably includes a lower shank section in the form of a blade carrier unit secured to the shank, the carrier unit having a forward leading blade attachment means and a rearward cutting blade attachment means, the rearward cutting blade attachment means preferably comprising a pair of spaced vertical plates receiving a cutting blade carrier unit in the form of an inverted generally T-shaped plate. Each cutting blade is preferably tapered, having a broad forward cutting edge portion located behind the inside the periphery of the leading blade. Each cutting blade preferably has a forward portion located within the shadow of the leading blade." 11 Reference is then made to the drawings accompanying the specification. I will not set out the explanation given of them in the specification. Parts of that discussion will be dealt with at later points in these reasons. The first two drawings show a side view of an overall assembly of the frame and tool bar. Figures 3 and 4 assume greater relevance in the proceedings and are here set out. 12 The claims of the petty patent, and claims 1 to 3 of the standard patent, are in these terms: "THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A row cultivator having a transverse tool bar and a plurality of tool carrying shanks mounted on and projecting downwardly from the tool bar, each shank having a pair of plates mounted to the shank on opposite sides of the shank and forming a lower shank section, the lower shank section having a forwardly projecting portion fitted with a leading blade and a pair of rearward cutting blade attachment means having respective cutting blades attached thereto so as to be spaced rearwardly from and separate of the leading blade, the leading blade being followed by the pair of cutting blades, the cutting blades being adapted to travel just below soil level to sever weeds on either side of the leading blade, the cutting blades having respective leading edges diverging rearwardly and outwardly on opposite sides of the leading blade. 2. A row cultivator according to claim 1 wherein the pair of plates are pivotally mounted on the shank so that the inclination of the cutting blades can be adjusted. 3. A row cultivator according to claim 1 including means for changing the inclination of the blades." 13 Of the additional claims in the Standard patent, claims 4, and 9 to 13 inclusive are relevant to infringement: "4. A tool for a row cultivator, the tool comprising: an elongated shank having an upper shank section and a bifurcated lower shank section pivotally coupled to the upper shank section, the lower shank section comprising leading blade attachment means projecting in a forward direction from the shank, and a plurality of cutting blade attachment means physically separated from the leading blade attachment means in a rearward direction from the leading blade attachment means; a leading blade for cultivating a furrow, said leading blade being mounted to the leading blade attachment means of said shank, and having a rear end; and a pair of cutting blades, adaptable to travel just below a soil level to sever weeds on either side of the leading blade, the pair of cutting blades having respective forward ends and leading edges diverging rearwardly and outwardly on opposite sides of a line passing through the leading blade, and being secured to the respective cutting blade attachment means such that the rear end of the leading blade is physically separated from respective front ends of the cutting blades. … 9. A tool according to Claim 4, wherein each cutting blade is tapered, having a broad forward cutting edge portion located behind and inside a periphery of the leading blade. 10. A tool according to Claim 4, wherein each cutting blade has a forward portion located within a shadow of the leading blade. 11. A tool according to Claim 4, including means for changing an inclination of the blades. 12. A tool according to Claim 4 wherein the lower shank section comprised interfitting plates, said cutting blade attachment means comprising a pair of lobes for separate attachment of the respective cutting blades to the lower shank section. 13. A row cultivator employing a tool according to any one of claims 4 to 12."