This is a short note to report on a successful interlocutory application seeking a declaration that a patent amendment amounted to an abuse of process. The Federal Court in Kutti Bay Investments Pty Ltd v Rattlejack Innovations Pty Ltd [2026] FCA 422 has found that patent amendment applications can be an abuse of process if they seek to overcome earlier judicial decisions in relation to related patents. While such amendments can be permissible (for example, to overcome novelty-destroying prior art), they cannot be deployed to construe the patent in a manner that directly contradicts earlier judicial findings.
Background
In 2024, Kutti Bay Investments Pty Ltd (formerly Jusand Nominees Pty Ltd) sued 4 respondents for infringement of 3 standard patents relating to a safety system for use in mining. These standard patents share a priority document with the 3 innovation patents previously litigated in Jusand Nominees Pty Ltd v Rattlejack Innovations Pty Ltd [2022] FCA 540 and the appeal in Jusand Nominees Pty Ltd v Rattlejack Innovations Pty Ltd [2023] FCAFC 178 (which upheld the trial decision). In the Jusand proceedings, the Court held that:
- the asserted claims were invalid for lack of sufficiency and support – the patents gave no guidance in making a safety system from materials other than steel (where the claims were not so limited), and
- the respondents’ products did not infringe, because of findings on claim construction.
As part of the current proceeding, Kutti Bay applied to amend the standard patents to:
- insert a new statement concerning the common general knowledge relating to suitable materials to overcome the s 40 findings, and
- otherwise amend the specification and the claims to overcome the construction findings.
Findings
The respondents sought, and the Court granted, a declaration that the amendment application was an abuse of process to the extent it sought to overcome the Jusand decisions. Although it is not inherently an abuse of process to attempt to overcome earlier judicial decisions (such as amendments which might overcome prior art citations), the circumstances of this case meant that there was such an abuse.
Kutti Bay characterised most of the amendments as correcting ‘obvious mistakes’ (pursuant to s 102(3)(a) of the Patents Act, which is the one exception to the prohibition on broadening amendments which enlarge the scope of the invention claimed). It relied on 3 new expert witnesses. The Court noted:
[Two experts] were asked to identify ‘the types of skilled persons working in the Field’ before they were given the Patents to read. … [T]he Field as provided to the experts differed from the Field of the Invention set out in the Patents. Both experts then elided their identification of the skilled persons working in the Field into the person skilled in the art before they had read the Patents.
This was then used to found the experts’ opinion that the mistakes the amendments were designed to correct were obvious.
The Court’s overall findings were underpinned by the following observations:
The Innovation Patents and the Patents share the same priority date. They also share the same description of the Field of the Invention and the Background of the Invention. No substantive difference has been identified between the specifications of the Innovation Patents and the specifications of the Patents which might justify the new experts’ different understanding of the invention disclosed and claimed in the Patents. For the purposes of the Abuse Application, there is no material difference between the specifications of the Innovation Patents and the Patents.
As a consequence, the Court found no basis to depart from the findings in the Jusand proceedings regarding the skilled person or common general knowledge.
For there to be an ‘obvious mistake’, the error and the appropriate correction must be clear on the face of the specification, without relying on extraneous evidence beyond what is required to equip the court with the knowledge of the skilled person. The additional expert evidence was extensive and was inconsistent with Kutti Bay’s evidence and admissions made in the Jusand proceedings. The observation in the judgment that ‘mental contortions [would be] required for the Court to accept the existence of an obvious mistake in the specification’ is a succinct summary of why the obvious mistake argument was rejected.
In light of the above, the amendment application as it was framed and insofar as it relied on correcting ‘an obvious mistake’ was found to constitute an abuse of process. The Court concluded:
The prosecution of such an application would bring the administration of justice into disrepute, as in order to find the existence of an obvious mistake, the Court must accept that the construction of the new experts is correct, and that the Court was led astray in its original construction by the obvious mistake on the face of the specifications.
It will be interesting to see what comes next. Regardless, the judgment provides a neat summary of the general principles of abuse of process and the scope of obvious mistake.
