Chocolate teapots and nuclear bombs: Whole range sufficiency of mechanical inventions (T 0149/21)

A question that confuses discussions on sufficiency is whether certain sufficiency tests are applicable to only certain types of invention. However, according to the established case law of the EPO, the underlying test for sufficiency is consistent, regardless of the type of invention. The test is always whether there is substantiated doubt that a skilled person would be able to perform the invention in view of the disclosure of the application as filed and common general knowledge (CGK). A recent decision from the Boards of Appeal (T 0149/21) confirmed that "whole range sufficiency", i.e. that a skilled person should be able to perform the invention of the whole scope of the claim, should not be considered specific to the fields of chemistry and medical use. If there is doubt with regards to a broadly claimed feature, then more evidence is needed to overcome this doubt, regardless of the technical field. 

Basic Sufficiency 

Rolling mills

In order to be sufficiently disclosed under Article 83 EPC, a detailed description of at least one way of carrying out the invention must be given in the application (Rule 42(1)(e) EPC). An objection of insufficiency requires there to be serious doubts, substantiated by verifiable facts, that the skilled person would be able to work the invention. In many cases, the sufficiency bar is low and can be satisfied by providing a single example falling in the scope of the claim in the application as filed.

However, for certain types of invention there may be a higher level of underlying doubt about whether the invention can be worked by a skilled person. These inventions include those relating to therapeutic uses and those involving broadly claimed features, such as a broad range of parameter values, functional features, or a broad genus of compounds. In such cases, there may be a high level of underlying doubt that a skilled person would be able to work the invention across the full scope of the broadly claimed feature (CLBA, II-C 5.4) ("whole range sufficiency"). Additional evidence is therefore required to meet the sufficiency standard requirement for these types of invention. 

Taking account of unknown unknowns (T 0149/21)

The patent in question in T 0149/21 (EP2630545) claimed a method for reducing the energy consumption of a rolling mill. Claim 1 particularly claimed a method including the step of identifying a fault leading to an unplanned pause of the rolling mill. The fault is then communicated to a control device. The control device anticipates the duration of the unplanned pause in rolling, depending on the nature of the fault, and powers down certain components of the mill as appropriate in order to save energy. 

At Opposition, the Opposition Division was satisfied that the sufficiency requirement was met in view of the single example provided in the application as filed. Particularly, the application as filed described a control device that had a database of common faults (and their associated delays) that it could use to identify a fault and anticipate the expected duration of the pause in rolling. The application as filed provided an example whereby faults were identified and inputted into the control device by a user. 

However, the claim was not limited to the faults specified in the database of common faults, or to a method in which the faults were manually identified. The broad language of the claim covered automatic detection of all possible faults, including those which were unknown (the unknown unknowns). On appeal, the Opponent argued that the claim was not sufficiently disclosed over the whole scope of the claims, particularly with regards to these unknown faults. 

Whole range sufficiency and chocolate teapots

The first question for the Board of Appeal was whether "whole range sufficiency" was a test specific to the chemical field. The Board of Appeal noted a recent decision implying that "over the whole scope of the claim" did not necessarily apply to inventions outside of the chemistry field. Particularly, it was suggested in T 1983/19 that "whole range sufficiency" could not be transferred to the mechanical field because almost every mechanical claim could be said to cover any number of impractical and non-working embodiments. This argument recalls the "chocolate teapot" thought experiment discussed by Mr Justice Birss (as then was) in Illumina v MGI ([2021] EWHC 57 (Pat), IPKat), whereby a claim to a new teapot may be construed as including within its scope the impractical and non-working embodiment of a chocolate teapot. 

For the Board of Appeal, the chocolate teapot problem is easy to overcome if it is remembered that a skilled person will use the direction of the application as filed and their common general knowledge (CGK) to interpret and carry out the claimed invention and exclude non-working embodiments. A skilled person would already know from CGK that a chocolate teapot would not function as a teapot (EPO Guidelines for Examination, F-III, 5.1). Mr Justice Birss (as then was) solved the chocolate teapot problem by finding that the invention only needs to be disclosed over the whole scope of the claim with respect to features relevant to the core inventive concept of the claimed invention (IPKat). The Board of Appeal also noted that there were many cases outside the chemical field which had applied the "whole range sufficiency" test, including those in the fields of electrical engineering (T 1542/12, T 2210/16, T 1306/17), physics (T 2305/14,  T 1921/19, T 0222/17) and mechanics (T 1905/10, T 2431/11).

Airplanes and nuclear bombs

The Patentee in the present case argued that it would be excessive to require the invention to be sufficiency disclosed with respect to all the unknown unknowns falling under the scope of the claim, and that it should be sufficient for one example to be provided in the application as filed. The Patentee argued that it would be absurd to require the application to show that the invention could be worked by a skilled person with respect to any kind of fault, e.g. a nuclear bomb or an airplane crashing into the rolling mill (equivalents to the "chocolate teapot" scenario). 

However, whilst the Board of Appeal agreed that in many cases one example may be sufficient, the bar might be higher for broadly claimed inventions. Particularly, it may be necessary to provide more evidence in cases of a broad claim in order to ensure the patent bargain was met (r. 3.6, T 0435/91). The Board of Appeal dismissed the Patentee's nuclear bomb argument, on the grounds that a skilled person would not consider these embodiments technically reasonable. The potential for the chocolate teapots is thus not an argument against a requirement of whole range sufficiency in the mechanical field.

With respect to the claim in question, the Board of Appeal also noted that there were many types of less extreme faults that would fall under the claim but for which the skilled person would not know how to work the invention. Furthermore, the claim covered within its scope automatic detection of faults, and from the disclosure of the application as filed, a skilled person would not know how to program the control device in order to facilitate this automatic detection. 

The Board of Appeal thus found that the claimed invention was not sufficiently disclosed, and that the patent as granted was invalid. 

Final thoughts

Attentive readers may have noticed that this post has not yet mentioned "plausibility". As demonstrated above, it is possible to discuss the issue of "sufficiency over the whole range of a claim" without having to use the term "plausibility" (IPKat). However, given that the whole range sufficiency test is equivalent to the whole range "plausibility" test, the present case can also be said to confirm that plausibility is relevant to the sufficiency of invention in the mechanical field. Furthermore, the Board of Appeal in the present case confirmed the established case law that whole range sufficiency may be applied to broadly claimed inventions in the mechanical field. Interestingly, the US Supreme Court in the recent decision on enablement in Amgen v Sanofi also took great pains to emphasise that the law of enablement of broadly claimed inventions was originally derived from, and continues to apply, to the mechanical field (IPKat). 

Further reading

• Kymab caught the mouse as sufficiency strengthened by UK Supreme Court in Regeneron battle ([2020] UKSC 27) (June 2020)
• Shining the light on insufficiency (T 1285/15) (August 2020)
• Illumina v MGI Part 1: Mr Justice Birss on sufficiency, DNA sequencing and chocolate teapots (Feb 2021)
• US Supreme Court decision in Amgen v Sanofi: The European Perspective (May 2023)
• Sufficiency of broad functional genus and first medical use claims in Europe (T 0424/21) (Oct 2022)
• Plausibility demystified - a review of EPO case law before G 2/21