Mechanical inventions are generally considered suitable for patent applications.
If the invention required practical difficulties to be first overcome with some ingenuity, or it provides some advantage, then it can be argued that the invention is suitable for a patent application.
Generally, mechanical inventions are a combination of features. If there is an actual or potential working interrelationship between the features, then the combination of features is considered suitable for patent applications. However, if there is no interworking relationship between the features then the invention is considered to be a mere collocation and is not patentable.
For example, it was stated in the British case British Celanese Ltd. v Courtaulds Ltd. 52 RPC 171:
“it is accepted as sound law that a mere placing side-by-side of old integers so that each performs its own proper function independently of any of the others is not a patentable combination, but that where the old integers when placed together have some working interrelation producing a new or improved result then there is patentable subject-matter in the idea of the working interrelation brought about by the collocation of the integers.”