The first appellant manufactures a 'swivel holster' for handheld firearms, which both appellants sold in South Africa. The respondents are joint registered proprietors of South African Patent ZA 98/6778 entitled 'A Lockable Holster'. The respondents sued the appellants in the Court of the Commissioner of Patents, claiming that the swivel holster infringed their patent and seeking consequential relief including an interdict, delivery up for destruction, and an inquiry into damages. The appellants filed a counter-claim contending that the patent was invalid as the invention was not patentable under s 25 of the Patents Act 57 of 1978 and should be revoked. The court a quo found in favour of the respondents, dismissing the counter-claim, declaring the patent valid, and granting an interdict and other relief. The appellants appealed against the order granting relief for infringement, but did not challenge the dismissal of their counter-claim or the declaration of validity.
The appeal succeeded with costs. Paragraph (c) of the order of the court a quo was set aside and substituted with an order dismissing the plaintiffs' (respondents') claims flowing from the alleged infringement of South African Patent ZA 98/6778, with the parties ordered to bear their own costs in the court below. The portions of the order relating to the counter-claim and the validity of the patent (paragraphs (a) and (b)) were not challenged on appeal and remained standing.
For patent infringement to be established, the allegedly infringing article must contain each and every essential integer of the patent claim as purposively construed. When interpreting patent claims, a purposive construction must be applied having regard to the full context and background including the specification, to determine what a person skilled in the art would understand the claim to mean. A 'camming surface' is a surface at which motion is imparted to convert one kind of motion or displacement to another kind through a specially designed profile - a surface designed to block motion rather than convert motion does not constitute a camming surface. Where the language of a patent claim specifies particular elements acting in a particular relation to one another as essential features, there is no infringement of the monopoly unless each and every one of such elements is present in the allegedly infringing article and such elements also act in relation to one another in the manner claimed. The function of claims in a patent is to limit and not extend the patentee's monopoly - what is not claimed is disclaimed.
The court made observations about the expert evidence regarding whether the appellants' holster could deform under extraordinary force to cause the locking lug to act as a cam. The court stated that even if such deformation could occur, it would be irrelevant to the process of interpreting the patent to decide whether a part should be viewed as a camming surface. The issue is whether the holster as designed infringes the patent, not how individual parts might operate if the holster is deformed through extraordinary force. This suggests that hypothetical scenarios involving extraordinary circumstances beyond the normal design parameters are not relevant to patent infringement analysis. The court also noted, without deciding, that it was unnecessary to determine which expert's view was correct regarding whether deformation could cause the locking lug to rotate sufficiently to act as a cam.
This case provides important guidance on the interpretation of patent claims in South African law, particularly regarding the application of purposive construction and the requirement that all essential integers of a claim must be present for infringement to be established. The judgment emphasizes that patents must be interpreted purposively to extract the essential elements of the invention, having regard to the full context and background including the specification, to decide what a person skilled in the art would understand the claim to mean. The court reinforced the fundamental principle that infringement requires the presence of 'each and every one of the essential integers' of a patent claim - similarities between products are insufficient if even one essential integer is absent. The case also clarifies the definition and function of 'camming surfaces' in patent law, establishing that a surface designed to block motion rather than convert motion from one direction to another does not constitute a camming surface. The judgment demonstrates the limits of patent monopolies and the importance of clear claim drafting, reiterating the principle that 'what is not claimed is disclaimed'.