First published in EPLAW, December 2019

This judgment from the Patents Court (Her Honour Judge Clarke sitting as deputy) considers the application of the law on infringement by equivalents.

The case was heard under the Shorter Trials Scheme which applies to trials that can be heard in four days or less and aims to save costs. The Defendant had argued previously for the case to be taken out of the scheme on the basis of its complexity, the nature of disclosure needed and the likely length of the trial. The judgment of HHJ Pearce from 10 October 2018 refusing that application can be found here.

Background

Excel-Eucan Limited, the Claimant (“Excel”), holds two UK patents, GB 2 489 116 (“GB 116”) and GB 2 523 562, which relate to a product called the Link-Tail. The Link-Tail is an ammunition bag for holding linked rounds of ammunition on a piece of webbing or material so that the ammunition can be fed easily into a machine gun. Source Vagabond Systems Limited, the Defendant (“Source”), manufactures and sells ammunition bags to the Ministry of Defence (“MoD”) in the UK.

The parties had previously entered into a licence agreement for Source to manufacture and sell the Link-Tail to the MoD in the UK. However, Source went on to develop a separate ammunition bag which it claimed was not developed from the Link-Tail and did not fall within the scope of the claims of Excel’s patents.

The action included a dispute over an alleged breach of the licence agreement, as well as a claim by Source for a declaration of non-infringement (DNI) covering its new ammunition bag (the “2017 Bag”) with respect to GB 116. Validity was not in issue in these proceedings because Source commenced separate revocation proceedings before the UKIPO against both patents in 2018. The parties agreed therefore that the Judge should approach the DNI application on the assumption that GB 116 was valid.

Infringement by equivalence

The Supreme Court in Actavis UK Limited & Ors v Eli Lilly and Company [2017] UKSC 48 (“Actavis”) set out a two stage approach to assessing infringement:

  1. does the variant infringe any of the claims as a matter of normal interpretation; and, if not,
  2. does the variant nonetheless infringe because it varies from the invention in a way or ways which is or are immaterial?

The parties agreed that the 2017 Bag did not fall within the scope of claim 1 of GB 116 on the basis of its “normal” interpretation (stage (i) above), because it did not have “an openable closure extending substantially from the first end to the second end” which was a feature of claim 1. Excel contended, however, that the 2017 Bag constituted an immaterial variant which nonetheless infringed claim 1 by equivalence. HHJ Clarke therefore applied the reformulated Improver Questions with the following answers.

Does the variant achieve substantially the same result in substantially the same way as the invention i.e. the inventive concept revealed by the patent? Yes

Excel argued, and the Judge accepted, that the inventive core of GB 116 was its “plug and play” functionality such that the ammunition can be fed into the firearm without the need to remove it first from the bag. The 2017 Bag was considered by the MoD to be substitutable for the Link-Tail bag and this supported the Judge’s finding that the variant bag achieved the same result as the Link-Tail. The Judge then considered whether the different methods for loading the bags achieved the result in substantially the same way. Since the opening of the bag did not dictate the way the ammunition was positioned in the bag and since the patent was not limited to only one method for loading the bag, the different methods were considered substantially the same by the Judge.

HHJ Clarke also observed that Source’s argument that the invention should be defined by reference to the claims placed too much emphasis on the words of the claims, making the argument “circular”; the whole point of the doctrine of equivalence is to look beyond the wording of the claims to find the inventive core.

Source sought to rely on comments made by the IPO Hearing Officer and by Excel during prosecution in order to demonstrate the importance of the openable closure feature. HHJ Clarke applied the test from Actavis in order to assess whether this was a case where it would be helpful to have reference to the file history of the patent. She held that the file history neither unambiguously resolved the point nor would it be contrary to the public interest to ignore the contents of the file and therefore it did not assist.

Would it be obvious to the person skilled in the art reading the patent at the priority date, but knowing that the variant achieves substantially the same result as the invention, that it does so in substantially the same way as the invention? Yes

The Judge held that it would have been obvious to the skilled person that the way the ammunition was loaded in the variant bag could also have been used with the bag of the invention. Earlier she had noted that the way the ammunition would sit in the bag (brass-on-brass in a concertina formation) would be the same regardless of using a horizontal or vertical method of loading.

Would such a reader of the patent have concluded that the patentee nonetheless intended that strict compliance with the literal meaning of the relevant claim(s) of the patent was an essential requirement of the invention? No

The Judge had already held when answering the first question that this was not a case where it was appropriate to have regard to the file history, noting the test in Actavis. She held that the openable closure would not have been considered by the skilled person to be an essential requirement of the invention.

Given the responses to the questions, HHJ Clarke held that the 2017 Bag would infringe and refused the DNI.

The remaining issues related to the terms of the licence, Excel’s request for an inquiry as to damages for breach of the licence agreement and costs.

A copy of the decision can be found here.