United Kingdom
Catnic Components Limited and another v Hill and Smith Limited [1982] RPC 183 (HL) D
Improver Corporation and others v Remington Consumer Products Limited and others FSR [1990] 181 F
Southco Inc and another v Dzus Fastner Europe Ltd [1990] RPC 587
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Judgment
PLEWMAN JA
This is an appeal against an order by Roux J, sitting as Commissioner of Patents, in a matter concerning an alleged
infringement of a patent. The appellants are the registered joint proprietors of South African Letters Patent 90/2427
in respect of an invention entitled "Pressure Resistant Bag". They acquired this by an assignment from the original
patentees. The respondent manufactures and sells a competing product. Appellants applied in the court a quo on
notice of motion for a permanent interdict restraining the respondent from selling or offering its product for sale and
for an order for the delivery up of any infringing bags. The Commissioner dismissed the application with costs but
granted leave to appeal to this Court.
The patent was granted with effect from 27 February 1991. It was applied for by appellants' predecessors in title
in March 1990, claiming priority from three prior patent applications. It seems, however, that the respondent, too,
had been active in the field for some years. The affidavits filed in support of the notice of motion are of a somewhat
perfunctory nature. This may have had an influence on the response thereto by the respondent. There was
(unusually for patent litigation) no challenge to the validity of the patent. In the result there is on the record no
evidence in which the prior art is discussed in any depth. Perhaps more importantly, there is not any evidence to
show that the patent, when viewed through the eyes of the skilled addressee, should be read in any manner which
would give the words of the claims a meaning other than their primary meaning. This is an aspect to which I shall
return.
Page 545 of [1999] 2 All SA 543 (A)
In its commercial embodiment the patent takes the form of a bag used in the support systems employed
underground in mines. Mine support bags are fitted in or into packs of timber support in excavated stopes or other
underground working places. The bags are filled under pressure to wedge the timber supports into position. There
are two systems in use. In one system (known as the "weeping system") the bag is of a porous woven material
and is filled with grout. The water in the grout passes through the bag while the solids remain behind and set to
provide solid support. In the other system (the "nonweeping system") the bag is impervious to liquid and a
chemically reactive mix is pumped into the bag which hardens by chemical action to provide the support.
The specification is (fortunately) not a technically complex document. The general description of the invention in
the specification reads:
"This invention relates to a flexible bag which is resistant to damage from high internal pressure such as would be caused by
filling the bag to a high pressure with a liquid, grout or the like and to damage caused by loads and/or shock loads imposed
on the outside of the bag when the bag is filled with air or liquid under pressure."
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The consistory clause reads:
"A pressure resistant bag according to the invention includes a first bag which is made from an airimpervious plastics
material, an envelope which is made from a reinforced flexible material and in which the first bag is located, a second bag
which is made from reinforced flexible material in which the envelope is located and a filler arrangement which is attached to
the first bag and passes through apertures in the envelope and second bag. Conveniently, the first bag is made from an
unseamed tube of plastics material with the ends of the tube sealed to provide a closed bag.
Further according to the invention the envelope is in the form of an openended tube in which the first bag is located.
Preferably, however, the envelope is made from a woven plastics material with the weft threads of the weave conveniently
being circumferential in the tube and of a higher tensile strength than the warp threads.
In the preferred form of the invention the sealed ends of the first bag are transverse to the tube axis of the envelope and
are located on the inside of and adjacent the open ends of the envelope with the end portions of the envelope together with
the sealed end portions of the first bag being folded back on to an outer surface of the tube with the first bag and envelope
being so located in the second bag."
In infringement proceedings one is concerned only with the invention claimed. The patent has twenty claims but
what is in dispute between the parties can be dealt with having regard only to the main claim. Indeed, only one
integer is in dispute and in that regard it is, in the main, the bearing one phrase has on the construction of that
claim that must be debated. The claim may, for convenience, be set out as having the following integers:
"(i)
A pressure resistant bag including
(ii)
A first bag which is made from an airimpervious plastics material
(iii)
An envelope which is made from a reinforced flexible material and in which the first bag is located