Patent strategies are vital for businesses and a balance must be found between cost-effectiveness and the highest possible level of protection. It is often advantageous to file a provisional patent application for an invention's numerous different components, which could be new inventions in themselves and – instead of linking separate components to a single invention – could qualify for separate patent protection.
Unity of invention is a basic rule of patent law. While a lack of unity is not grounds for the revocation of a patent, the Patent Act states that a patent may be granted only for a single invention. If a patent application contains several inventions not linked in any way, there would be a lack of unity. The filing of a divisional patent application therefore offers the applicant the option of obtaining patent protection for different inventions originally disclosed in a single patent application (the main or parent application), without risking invalidation by virtue of anticipation. Divisional applications can be filed at any time before the parent application is accepted, and must then be antedated to a date no earlier than that on which the parent application was filed. Patent term extensions are impossible and the divisional application will expire at the same time as the parent application. Filing of continuation or continuation-in-part applications is also not provided for, although the law does provide for the filing of a patent of addition.
The Patent Act does not specifically exclude cascades of divisional applications (ie, the filing of a divisional application on the basis of another divisional application). However, the legislation is unclear on whether a divisional application filed on the basis of a parent divisional application can be antedated to the first parent application's lodgement date, which may introduce a risk of invalidation by virtue of anticipation. The direct parent application must still be pending for a second divisional application to be filed.
When filing a divisional application, it must concern the matter disclosed in the parent application. The description cannot include matters that were not disclosed in the parent application. In general:
- the body of the divisional application's specification will be the same as that of the parent application; and
- the divisional application's claims will be a sub-set of those in the parent application and cannot exceed the original disclosure.
Acceptance of a patent application generally occurs 12 months after the filing of a national phase application (or 18 months after the filing of a complete application). Even once the Patent Office has accepted an application, it can be withdrawn and delayed to allow the applicant to consider possible amendments and the filing of a divisional application.
The Patent Act does not specifically exclude double patenting, but the legislation's intention is to divide the claims of a parent application by removing some of the claims and including them in the divisional application. However, South Africa is not an examining country and double patenting may thus occur when the divided parts of the claim are not removed from the parent application.
The filing of a divisional patent application can open up the options for patent strategy, in order to pursue patent protection in a more targeted and comprehensive manner. To obtain a higher degree of protection, applicants must have a clear understanding of the optimal timeframe for filing a divisional application and claiming amendments to their parent application.