(American Heritage Dictionary sv "support".) No inconsistencies exist between the wording of the specification and
these definitions and if it be borne in mind that support can be vertical or lateral, more need not be said about the
meaning of "selfsupporting".
Another term in claim 1 that conveniently can be dealt with at this stage, is to be found in integer (j). That
integer states that the selfsupporting properties may be provided by additional welded stiffening zones "if
desired". The appellant's case is that because of these words the claim does not sufficiently and clearly define the
subject matter for which protection is claimed and is for that reason invalid. MacArthur J held that the effect of the
option given by the words is to reduce integer (j) to an inessential integer. The result of his finding is that the
monopoly covers not only a filter with, but also one without additional welded stiffening zones. Put differently, the
claim can be divided notionally into two claims. Mr Franklin for the appellant attacked the finding and relied upon the
reasoning of Van Dijkhorst J in Ian FraserJohnston v GI Marketing CC 1993 BP 461 (CCP) at 477FG. He held that an
integer in a dependent claim which is "preferably provided" renders the claim unclear because one does not know
whether the integer is part of the claim. (This judgment was confirmed on appeal, but the finding on this aspect of
invalidity was not in issue: GI Marketing CC v FraserJohnston 1996 (1) SA 939 (A) 942FG.)
There is little, if anything, to be gained by comparing the use of similar terms in different contexts to find the
meaning or effect of one of them. Nor is there any justification for enquiring whether Van Dijkhorst J's judgment
was, in the
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circumstances of that case, correct or not. The question remains whether integer (j) renders this claim uncertain or
unclear. In my judgment it does not and I fully agree with MacArthur J that the formulation used merely indicates
that the integer is inessential in the sense described.
Infringement
To prove infringement, the patentee relied upon the evidence of Mr Reuvers who said that he found all the integers
of claim 1 in the appellant's product. I have already mentioned that the appellant admitted that it had copied the
patentee's commercial product. The appellant sought to establish that neither its product nor that of the patentee
fell within the scope of claim 1 because, so it was said, the selfsupporting properties of both filters were derived
from the nature of the filtering material and not from the weld (integer (g)) or the spacer elements (integer (h)). To
establish the proposition and to gainsay Reuvers' evidence, the appellant relied upon experiments conducted by
Messrs Couchman and Mostert.
Reuvers' evidence is subject to the criticism that his opinion that the selfsupporting property of the appellant's
product was derived from the weld and the spacers was not supported by reasons. His testimony can be read to
mean that because the pocket is selfsupporting and has welds and spacers, the selfsupport derives from the
welds and spacers. If he intended to say so, he was mistaken. The specification does not promise,
View Parallel Citation
nor is it a scientific fact, that welds and spacers used on filter pockets of a suitable material inevitably produce a
filter with selfsupporting properties.
On the other hand, I have some difficulty in appreciating the relevance of the appellant's experiments. A filter
element without spacers was made of the same material as the allegedly infringing filter, but instead of being
welded the pockets were sewn some distance from their edges and a blanket stitch was sewn around the border
formed. Weights were attached to both elements and the resistance of the experimental model to sagging was
compared to that of the appellant's commercial product. The latter gave way under less weight than the former.
From this one can deduce that a filter pocket with the particular stitch on the particular material has greater self
supporting properties than one with welds and spacers. That does not prove that the selfsupporting characteristic
of this product is not the consequence of the welds and the spacers, whether assisted by the nature of the material
or not. As counsel for the appellant repeatedly and correctly stressed, if the selfsupporting ability derives from
something in addition to the welds and spacers, infringement is not avoided. In view of Couchman's concession that
the welds and spacers, to a limited extent, support the appellant's filter element laterally, having regard to the
principle just stated and the meaning of "selfsupporting" dealt with earlier, it follows that the court below correctly
found for the patentee on the question of infringement of claim 1.
Claim 5, according to Mr Moldow, an expert called by the appellant, was also infringed and I did not understand
Mr Franklin for the appellant to seriously contend otherwise. This claim differs from claim 1 inasmuch as it does not
require the pockets to have a selfsupporting property provided by welds and spacers although the pockets are
welded and have spacers. These, according to the specification, are for stiffening and stabilising the pockets and to
provide optimum inflow conditions. The welds, the specification says, provide a proper seal and nothing more. It is
unnecessary to dwell any further on the subject
Page 246 of [1998] 1 All SA 239 (A)
because it was not shown that MacArthur J had erred in holding this claim to have been infringed.
Invalidity general
I have disposed of "ambiguity" of claiming while dealing with the interpretation of the specification. Inutility, lack of
novelty and lack of subjectmatter (obviousness) remain. It is trite that each objection must be considered in