In most countries, patent law distinguishes between different categories of patent claims. Article 52 of the Federal Law on Patents for Inventions ("LPI") contains a list of different categories of patent claims. Effectively the law differentiates between method claims  and product claims.

This fundamental distinction is not a mere theory: On one hand the protection granted by a patent depends on the category of the patent claim. On the other hand Article 67 LPI states the for practice important presumption that, if the patent concerns a method for the manufacture of a new product, every product of the same composition shall be presumed to have been made according to the patented method until proof to the contrary has been provided.


Example of a claim of the depicted invention of Rieter AG, Winterthur, as given in the Figure: "... ring spinning machine ..., characterised in that, a threshold value for the yarn hairiness is predetermined...". Patent claims are the core of every patent. They define the scope of protection of a patent.