The importance of semantics


Muhammed Vally

South Africa’s Supreme Court of Appeal was confronted with an interesting case in Mantella Trading 310 v Kusile Mining, where the disputed issues, outside of the expected ones of patentability and infringement, concerned sufficiency.

The respondent, Kusile, had convinced the court of first instance that the patent, directed to ventilation systems for mining operations, was liable to revocation on the basis of lack of inventive step. On subsequent appeal, the court disagreed. 

Kusile raised the following grounds in support of its claim for revocation (brought in reaction to a claim for infringement):

The claims of the patent were not based on matter disclosed in the patent specification;

The claims were otherwise unclear; and

The patent failed to sufficiently describe, ascertain and where necessary illustrate and exemplify the invention and the manner in which it is to be performed, thereby preventing the skilled addressee from performing the invention. 

Many of the arguments on appeal (including that of inventive step) revolved around the words “rigid material” as used in the specification. In relation to the ground of insufficiency, without any specification-based dictionary for the term (and also without any special meaning derivable from the industry), the Supreme Court concluded that the phrase must be given its ordinary grammatical meaning. 

Three expert witnesses offered testimony. This was done in order to construe the claims purposively, meaning these must not be read in isolation but instead be read in the context of the whole of the specification. A court’s understanding of the specification through an expert’s eyes would also answer the ground of lack of clarity. 

Meanings that are consistent with that of the overall specification are meanings to be accepted as demonstrative of the intention of the author (and through it the patentee) at the time of drafting.  A dictionary having several meanings of a word provides a guide to its interpretation, bearing in mind its context in the specification.

The court also described who the skilled addressee is. In summary he or she is someone who is expected to bring reasonable intelligence to bear on the language of the specification, and who, while not required to struggle unduly with it, is to make the best of it and not adopt an attitude of studied obtuseness. 

"When a witness, particularly one testifying in support of obviousness, uses words such as 'imaginative' and 'creative', it tends instead to support a conclusion of inventiveness and hence patentability."

On the basis of expert testimony, the court ruled against the sufficiency arguments. 

Infringement was an admitted issue, as the court took account of the fact that the infringing articles bore similar materiality to the patent claims. Having copied the very feature that was attacked as being insufficient (or insufficiently worded) in the writer’s view probably assisted the court in holding against the insufficiency argument.  

Turning now to deal with lack of inventive step, the court noted that the invention was a simple one that brought together known elements in achieving its result. The court of first instance held that its very simplicity contributed to its invalidity, and although it cautioned itself against a hindsight argument of invalidity, upheld revocation.

It reasoned that even though different methods were employed between the cited prior art and the invention subject of present scrutiny, these methods achieved the same effect, which the court saw as a ground confirming revocation. While this appears at face value to be a decision against the existence of the doctrine of equivalents, no explicit argument was raised in this regard. 

In dealing with the question of obviousness, the court relied on the well-known test of obviousness, which essentially is represented by four questions, namely to identify the inventive step, to define the state of the art, to identify the differences between the invention and the state of the art, and to quantify such difference with regards to obviousness. Using this test, the judges of appeal disagreed with the findings of the lower court.

When a witness, particularly one testifying in support of obviousness, uses words such as “imaginative” and “creative” its use tends instead to support a conclusion of inventiveness and hence patentability, irrespective of simplicity. What further assisted the appeal court to maintain its position in favour of inventive step was that the patented article fulfilled a long established need in the field and enjoyed commercial success. 

The judgment is a sound one and its reasoning represents a comprehensive list of questions one would have to answer, whether as patentee or applicant, for revocation. It is therefore a recommended read for future or current patent litigants in the South African context. 

Muhammed Vally is a patent director at DM Kisch. He can be contacted at:

Muhammed Vally, DM Kisch, Mantella Trading 310 v Kusile Mining, patent, patent infringement,