Nampak Products Ltd and Another v Man-Dirk (Pty) Ltd

• Jurisdiction: South Africa
• Judge: Vivier JA, Howie JA, Schutz JA, Plewman JA, Melunsky AJA
• Judgment Date: 26 March 1999
• Citation: 1999 (3) SA 708 (SCA)
• Docket Number: 162/97
• Hearing Date: 05 March 1999
• Counsel: C Puckrin (with him M Jansen) for the appellants L Bowman (with him Brahm Du Plessis) for the respondent
• Court: Supreme Court of Appeal

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 C registered joint proprietors of South African Letters Patent No 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 D 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, E 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 F 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.

In its commercial embodiment the patent takes the form of a bag used G 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 H 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 'non-weeping 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 I 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.' J

Flewman JA

The consistory clause reads: A

'A pressure resistant bag according to the invention includes a first bag which is made from an air impervious 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 B 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 open ended tube in which the first bag is located. Preferably, however, the envelope is made from a woven plastics material with the weft C 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 D 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...