Delegate Covers Some Key Patent Principles

On 8 November 2007, the Delegate of the Commissioner of Patents handed down Go 4 Mining Pty Ltd v CMTE Development Limited [2007] APO 37.

This case is useful because the Commissioner refers to a number of principles that have shaped Australian patent practice.

Clarity of Claims

The opponent, CMTE, said that the words "said outer boom sheave being supported by a boom sheave support arm to one side of a longitudinal axis of said excavator boom..." rendered claim 1 unclear. The Delegate called that feature "X".

The Delegate disagreed and said that it simply means that the axis does not pass through the sheave. The Delegate considered the other known constraints and decided that one of the possible interpretations would lead to an unlikely construction.

The lesson is that the claims are to be interpreted in the shoes of a person skilled in the art and applying common sense.

Fair Basis

CMTE said that there was no real and reasonably clear disclosure of X, which appears only in the claims and consistory clauses (i.e. paragraphs in a summarizing portion of the specification).

The High Court considered Fair Basis in Lockwood Security Products Pty Ltd v Doric Products Pty Ltd [2004] HCA 69. The test is:

(a) whether the claim travels beyond or is inconsistent with the disclosure of the specification as a whole; and

(b) whether there is a real and reasonably clear disclosure of the claimed invention in the specification.

The Delegate was unable to "detect anything in the specification that is inconsistent with respect to this feature". He also said that the drawings provided the necessary "real and reasonably clear disclosure".


The Delegate referred to some old classic cases when setting out the basic rules for novelty testing as follows:

To deprive a claim of novelty, the prior art document must:

(a) clearly teach all the essential features of the claim; and

(b) provide "clear and unmistakable directions" to do what is claimed.

It became necessary for the Examiner to assess which features of the claim were essential. He cited the well-worn British case of Catnic Components v Hill & Smith [1982] RPC 183. The judges in that case concluded that a feature is essential to a claim if:

(a) it was essential to the working of the invention or if it materially affected the way in which the invention worked; or

(b) the applicant or patentee regarded the feature as essential.


This matter is worth reading if only as a reminder of some of our basic principles.


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