Home > Insights > Spare parts and patent infringement: Guidance from The Supreme Court
9 April, 2013

The Supreme Court has recently issued their judgement on the case between Schütz (UK) Limited (Schütz) and Werit UK Limited (Werit) concerning the legitimacy of manufacturing replaceable parts which are part of a patented product.

Case background
The case concerns a patent relating to intermediate bulk containers (IBCs). An IBC is designed to carry liquids in tough transport conditions. Each IBC is formed of a bottle and a supporting cage. The main claim of the patent included both the bottle and the supporting cage of the IBC. However its inventive concept related to how the bars of the cage were welded together. The bottle was not a particularly important feature of the claim.

Werit manufactured replacement bottles for use in these cages once the original Schütz bottle inside a cage had been damaged or corroded in use.

The main question which The Supreme Court had to decide on, was whether the action of re-bottling the patented IBC amounted to ‘making’ the patented product, and thus infringed the patent. The Supreme Court has ruled that it did not.

Test for infringing act
To help with this type of assessment, The Supreme Court has introduced a ‘subsidiary part’ test, which can be summarised as follows: if a part within a patented article can be considered to be subsidiary, then it can be replaced without infringement of the patent.

The Supreme Court has identified several factors which it found useful to consider when deciding whether a part can be classified as a subsidiary part:

a) whether the part in question is included within the inventive concept of the patented article, or has a function which is closely connected with that concept;

b) whether the replaced part is a free-standing item of property with respect to the rest of the patented article. In other words, whether the replaced part is fastened or connected to the rest of the article; and

c) what the life expectancy of the part being replaced is expected to be. For instance, if one would expect that a part should be replaced several times during the lifetime of a patented article, this might reinforce the notion that this part is a subsidiary part.

Given that the bottle was freestanding within the IBC, and was not related to the inventive concept of the patent in question (which was directed to the structure of the IBC cage), The Supreme Court deemed that the bottle from the IBC was a subsidiary part. Thus the act of re-bottling the IBC was found not to constitute ‘making’ the patented IBC.

This new test from The Supreme Court provides an interesting contrast to another recent case, United Wire and Screen Repair Service, which also provided guidance on what acts constituted ‘making’ the patented product. The facts of this case concerned patented vibrating filter screens which were used to remove drilling fluid from vibrating sifting machines. Each screen was made up of a mesh and a supporting frame which were connected together. The defendants in this case were engaged in removing the mesh from the frame, cleaning the frame, replacing the mesh with a new one and adhesively attaching the new mesh to the cleaned frame. In this case, the defendant’s actions were considered to constitute ‘making’ the screen, largely because there was more interaction between the mesh and frame during the replacement operation.

This decision from the Supreme Court is important for both original manufacturers of products with replaceable components and spare part manufacturers, since the decision provides guidance as to what will and will not be an infringement.

For original manufacturers, it is important that they think about how to prevent unwanted copies of any replaceable component within that product from being made or marketed.

Ideally patent protection should be sought for this component on its own. However, this is often not possible if there is nothing patentable in the component. In this case, a patent should be directed as much as possible towards how the replaceable component and main product interact since this may help establish that the replaceable component is part of the inventive concept, such that its replacement constitutes ‘making’ the patented product.

The position should be considered as early in the design stage as possible to try to engineer some features into the replaceable component, or its interaction with the rest of the product that can form the basis of a patent claim to prevent third party supply of the replaceable component.

Original manufacturers should also consider supplementing any patent protection concerning the replaceable component with other forms of intellectual property, for instance Registered Design protection.

For spare part manufacturers, The Supreme Court has made it clear that what constitutes ‘making’ the product depends very much on the facts of each case. Thus, before any spare parts are manufactured, it is important that the spare part be carefully considered to determine whether it can be classified as a subsidiary part.

For further information, please contact the Engineering and Designs group or your usual Boult Wade Tennant adviser.