The proceedings were brought as an application for leave to appeal a Declaration and Orders that were made in 2022 confirming the finding that Airco Fasteners Pty Ltd had infringed patent claims, with reasons for the Orders outlined in the Illinois Tool Works Inc v Airco Fasteners Pty Ltd judgement.2 The respondent, Illinois Tool Works Inc, was the patentee and the claims in question related to an in-can fuel cell metering valve, which is used in combustion tools.
The appeal raised two issues pertaining to whether the primary judge erred in determining that the combustion tool fuel cell supplied, imported, and sold by Airco. This included firstly finding that the combustion tool has ‘a fuel metering chamber disposed in close proximity to said closure’ (close proximity integer), and secondly, that the device has ‘a valve body having a second end opposite said fuel metering chamber located within said container’ (second end opposite integer).3
In the 2022 hearing, Justice Rofe construed the patent claims by referring to the terms ‘close proximity integer’ and ‘second end opposite integer.’ Airco argued that the term ‘opposite’ comprised different meanings throughout the document, and ought to have been construed to mean the ‘other end’ of the valve body.4 Airco similarly argued that Justice Rofe construed the term ‘proximity’ incorrectly, highlighting that ‘proximity’ indicated a requirement of closeness, which it argued that its devices did not include since the fuel metering chamber was furthest away from the closure.5
The appeal was dismissed since it was found that the trial judge’s construction analysis on the claims was correct despite Airco’s contention that the description of these terms conflicted with expert evidence they had adduced.
As a result of this decision, the Full Federal Court has affirmed long standing principles of patent construction and emphasised the importance of drafting patent specifications with caution. The decision further highlights that expert evidence cannot usurp judicial construction of a patent specification.
1 Airco Fasteners Pty Ltd v Illinois Tool Works Inc  FCAFC 7.
3 Ibid 4.
4 Ibid 34.
5 Ibid 37.