Always give your best (method)
Published on 19 Sep, 2017
Sandvik Intellectual Property AB v Quarry Mining & Construction Equipment Pty Ltd  FCAFC 138
- Applicants should include the best method(s) of performing the invention known at the time of filing a patent application, withholding better or superior embodiments or features can result in invalidity of the granted patent.
- Novelty destroying prior use does not always need to be corroborated by contemporaneous documentary evidence.
- Experts need to be carefully selected as an unsuitable expert will be less persuasive on inventive step issues.
- Claims are invalid for inutility where they include embodiments that are not useful.
This is a decision of the Full Federal Court of Australia (FFC) on an appeal from a judgement at first instance on the validity of Australian Patent Number 744870 (the Patent) in the name of Sandvik Intellectual Property AB (Sandvik) and its alleged infringement by Quarry Mining & Construction Equipment Pty Ltd (Quarry). The Patent and claims were directed to an extension drilling system for drilling holes to insert cable bolts in underground mines.
At first instance, it was held that claims 1 to 4, 6 and 7 of the Patent were not infringed and were invalid on the grounds of failing to describe a best method of performing the invention, lack of novelty, lack of inventive step and inutility. Sandvik appealed on all grounds.
The appeal decision
In respect of best method, the claims of the Patent did not define a water seal. However, evidence indicated that a water seal was a “real issue that needed to be overcome” for the invention to work. The Patent had only described a horizontal type seal member, whereas at the time of filing of the Patent, Sandvik had developed a superior seal member having upper and lower sections.
Sandvik submitted that the best method requirement should be assessed against the claimed invention or having regard to the “promise” of the invention relative to the problem to be solved. The FFC disagreed with both submissions, holding that the best method relates to the invention as described in the Patent. On this basis, the embodiments of the invention as described (not as claimed) omitted the superior seal member. Thus, the Patent was invalid for not meeting the best method requirement.
On novelty, three witnesses for Quarry provided evidence of invalidating prior use based on their personal recollection of a system 25 years before the priority date. No supporting evidence was provided, such as drawings, photographs, samples or documents. The FFC held that the absence of supporting evidence did not render the prior use evidence unreliable and referred to the trial judge’s opinion that the witnesses were credible under examination and cross-examination. Thus, the claims of the Patent in suit were also invalid for lack of novelty.
Sandvik was successful on the inventive step ground. The FFC held that the trial judge gave too much weight to one of Quarry’s experts, where that expert was shown not to be aware of information the parties had agreed was common general knowledge in the art and had mischaracterised other information as being common general knowledge when it in fact was not.
Dependent claim 4 recited that an extension rod could have a hexagonal or round cross-section that is driven by a chuck or an adaptor. However, evidence showed that if the extension rod had a round cross-section, it could not be driven either way to make the invention work. Accordingly, the trial judge held it lacked utility. On appeal, Sandvik sought to rely on a person skilled in the art would construe the claim using the principle of purposive construction in order to exclude this non-working embodiment. The FFC held that the proposed purposive construction could not overcome the plain and unambiguous meaning of the words in the claim. Thus, claim 4 was invalid for inutility.
This case provides a warning to applicants to ensure that the description of embodiments in a patent specification is updated prior to filing, especially when the application is claiming priority to an earlier patent application. Sandvik’s failure to include the superior sealing member rendered the Patent invalid even the sealing member was not claimed.
The case also demonstrates the importance of witnesses and experts. A credible witness can enable prior use evidence to invalidate a patent even where it is not corroborated by other contemporaneous documentary evidence. Similarly, an expert shown not to be a suitable person skilled in the art will undermine any inventive step arguments relying on that expert’s evidence.
The finding of inutility of claim 4 demonstrates that Applicants should be careful in drafting claims that include within their scope embodiments that do not work; otherwise the entire claim will be rendered invalid.