A common idiom employed in patent claims is to define an element of the invention in terms of its function. For example, a claim might recite an apparatus including a part ‘A’, and part ‘B’, and ‘means for fastening the part A to the part B’.
The purpose – under Australian law – of this so-called ‘means-plus-function’ language is to define the invention as broadly as possible. The patent specification might describe a number of different mechanisms for joining the two parts, e.g. nails, screws, and rivets.
But there may be other ways to achieve the necessary connection, some of which the inventor has failed to think of, some of which might be unknown to the inventor, and some of which might not even have been developed at the time of filing the application. By using broad, functional, language to define the fastening mechanism, the inventor gains the benefit of capturing all of these alternatives within the scope of the claim.
However, as a Full Bench of the Federal Court of Australian recently reminded everyone, there is a price to be paid, and a risk that is taken, through such broad claiming. In Garford Pty Ltd v DYWIDAG Systems International Pty Ltd  FCAFC 6, the court confirmed that ‘[a] claim to an apparatus for a particular purpose is a claim to an apparatus that is suitable for that purpose …. To establish infringement of such a claim it is not necessary for the patentee to establish that the apparatus is intended to be used for that purpose. The patentee need only show that the apparatus is suitable for that purpose’ (emphasis added).
Of course, what is true when assessing infringement after the date of the patent is also true when assessing novelty and inventive step based on information published before the priority date of the patent. And, unfortunately for the patentee, Garford, the Full Court disagreed with the primary judge, and found that the prior art disclosed an element of Garford’s patent claims expressed in means-plus-function form, namely ‘a feed means [suitable] for supplying a multi-strand cable from a rotatable supply reel’ (at ).
There is nothing new in this, from a legal perspective. It has long been established in Australian law that, when used in a patent claim, the word ‘for’ means only ‘suitable for’ and not, for example, specifically ‘adapted’ or ‘configured’ for the function. It is, however, a handy reminder that claiming broadly is a double-edged sword.
But this decision also got me thinking about the implications for applicants operating in multiple jurisdictions, because the way in which means-plus-function language is treated is not the same everywhere. The scope of claims using this format may be quite different, for example, in the US when compared with Australia, which has implications for both infringement and validity. And while means-plus-function claiming is unobjectionable in itself in Australia, a European examiner might refuse to allow a claim in this form if it is able to be expressed in more concrete terms.