T 345/09 – Not Enough

Even in the mechanical arts, one single example will not always be enough for establishing sufficiency of disclosure, as the present decision shows.

All four opponents filed appeals against the decision of the Opposition Division (OD) maintaining the opposed patent in amended form.

Claim 1 of the main request on file read (in English translation):

1. Process for the manufacture of a part with very high mechanical properties obtained after shaping by quenching when cooling, shaped by stamping of a strip of rolled steel sheet and more particularly hot rolled and coated with zinc or a zinc based alloy zinc ensuring protection of the surface and the steel, wherein:

• the steel sheet is cut to obtain a steel sheet blank,
• the steel sheet blank is hot stamped to obtain the part,
• an alloyed intermetallic compound is provided on the surface before the stamping, ensuring protection against corrosion, against steel decarburization, which intermetallic compound may provide a lubrication function, said compound being obtained by transforming the coating into an intermetallic alloy by raising the temperature beyond 700°C,
• the excess material from the steel sheet required for the stamping operation is trimmed. (the underlined parts correspond to amendments with respect to claim 1 as maintained by the OD)

The Board dealt in detail with the question of whether the invention was sufficiently disclosed (A 100(b) and A 83):

*** Translation of the French original ***

[3] According to claim 1 of all the requests, the claimed process results in “very high mechanical properties” […]. Therefore, first of all the question has to be answered which mechanical properties have to be considered for the invention and which values they have to be attain in order to be qualified as “very high” according to claim 1 of all the requests.

“Very high”

[3.1] The [opponents] have pointed out that claim 1 and the description of the patent do not provide clear information on that topic. They mention “very high mechanical properties” (paragraph [0004]) “high mechanical properties” (paragraph [0014], which does not concern the invention according to the patent any more, and paragraph [0021] in the context of quenching). Also in the context of quenching, [the description] mentions “high hardness and high surface hardness of the coating” in paragraph [0005]. No values for these properties are mentioned at all, with the exception of the breaking strength (résistance à la rupture) (1500 MPa) in figure 1.

The Board is of the opinion that these aspects do not need to be discussed because the invention is not sufficiently disclosed, for the following reasons.

Which mechanical properties?

[3.2.1] By amending claims 1 and the descriptions of all the requests (“very high mechanical properties obtained after shaping by quenching when cooling” … “in order to undergo quenching … by which said high mechanical properties are obtained”), the [patent proprietor] wanted to limit the claimed “very high mechanical properties” to those obtained at the end of the process, after quenching. The mechanical properties obtained before quenching, after hot rolling, even if “very high” did not play any role.

The Board cannot accept this argument because the patent as granted already claimed this result before the quenching in claim 1 and in the relevant parts of the description (paragraphs [0004], [0010] and [0020]). According to claim 2 of the patent as granted and to paragraphs [0005] and [0021] the high mechanical properties were also obtained by quenching.

In this context the argument of the [patent proprietor] according to which it was already implicit in the process of claim 1 of the patent as granted that the process included quenching and that claim 2 only added the value for one of these mechanical properties (hardness) cannot be accepted either because this distinction was clearly present in the patent as granted and is even underlined by the amendments of the description which the [patent proprietor] had to propose in order to eliminate it.

Also, the argument of the [patent proprietor] according to which the claimed process only concerned “press hardening” cannot be endorsed because none of the claims 1 on file does contain any indication that the quenching was carried out in the press.

[3.2.2] As a consequence, the opposed patent affirms in its paragraphs [0010] and [0020] that high (or increased) resistance to abrasion, wear and fatigue is obtained after the treatment consisting in raising the temperature, but before the stamping and even before the quenching. By alloying the coating with the steel, this treatment ensures not only a high hardness of the coating (paragraph [0015]) but also good lubricant properties (paragraphs [0021] and [0023]).

The quenching has to result (paragraph [0005]) in high hardness of the steel and of the coating and in high breaking strength (1500 MPa, figure 1).

As the process requires a sheet of rolled steel to be hot stamped, it is also obvious that the deformability (e.g. ductility and a certain resistance to rupture) before the stamping step constitutes one of these high mechanical properties, see also figure 1 showing a breaking of 500 MPa before stamping.

For all those mechanical properties – with the exception of the hardness of the coating of the rolled steel sheet after stamping – there is no example in the opposed patent. Even for this hardness (600 HV 100 g) the steel composition, which is important for forming an alloy with the rolled zinc (or zinc-based [alloy]) which then forms the coating.

[3.2.3] In consideration of the above, nine mechanical properties are referred to. Even taking into account the fact that there is a relationship between the hardness of the steel and its tensile strength (which is not identical to the breaking strength mentioned in the opposed patent, see above), in order to satisfy the requirements of A 83 there are still eight mechanical properties to be established by trials to be conducted by the skilled person in order to carry out the invention.

Parameters to be taken into account in the process steps

[3.3] The sole example of a final product in the opposed patent deals with corrosion resistance, which, however, is not a mechanical property.

In order to remedy the absence of relevant examples regarding the above-mentioned mechanical properties, which are essential to the invention, the skilled person would have to carry out a certain number of trials in order to establish what the invention is.

In such a case, when the question of whether the invention is sufficiently disclosed within the meaning of A 83 is to be answered, one has to establish whether the skilled person has to make an excessive effort when carrying out those trials, over the whole range covered by claim 1. It is also necessary to establish the parameters that are to be taken into account for those trials.

[3.3.1] The composition of the steel forming the sheet, which has to alloy with the zinc that is rolled onto the sheet in order to form the coating having the above-mentioned high mechanical properties, is one of the essential parameters. According to the sole example 1 of the patent the composition by weight of the steel (given in %) is as follows: carbon: 0.15 to 0.25; manganese: 0.8 to 1.5, silicon: 0.1 to 0.35; chrome: 0.01 to 0.2; titanium: less than 0.1; aluminium: less than 0.1; phosphor: less than 0.05, sulphur: less than 0.03; boron: 0.0005 to 0.01 (see paragraph [0022]). The example for a heat treatment by heating to 950°C does not mention this steel composition at all.

The claims 1 of all the requests do not give any indication on the steel composition; in view of the fact that quenching is needed following the hot shaping, the [patent proprietor] has also argued that that a carbon content between about 0.15 to 0.8 % by weight – which range is greater than the range given in the description of the patent – essentially determines the quenchability.

The steel composition and in “particular at least the content in carbon, in elements which are able to form carbides (i.e. manganese, molybdenum, vanadium, tungsten, niobium and titanium) and in boron have an influence on the quenchability. R1 [Guy Murry, “Transformations dans les aciers”, Techniques de l’ingénieur; traité matériaux métalliques, 1998; vol. MD1, dossier M1115], which is, as noted by the [patent proprietor] a compilation of general knowledge in the field of quenching steels when cooling them, shows these influences […].

As a consequence, at least the elements C, Mn, Mo, V, W, Nb, Ti and B of the steel composition correspond to at least eight parameters that have an influence on the quenchability and, therefore, on the mechanical properties of this steel after quenching when cooling.

The Board is of the opinion that even for such a carbon content of 0.8 % by weight, the opposed patent does not inform the skilled person allowing him to determine how to adapt the other components of the steel, not to mention carbon contents between 0.25 and 0.8 % by weight, which would still have to be included in the trials, assuming that claims 1 of all requests are indeed at least directed at steels that are hardenable by quenching.

[3.3.2] The trials on different steel compositions also have to take into account the zinc percentage that is to be used because claims 1 of all requests also refer, not only to a coating with 100 % of zinc but also to a coating with an “zinc based alloy”, as argued by [opponent] 03, i.e. having a zinc percentage of above 50 %.

[3.3.3] As some of the above-mentioned mechanical properties (coating hardness, lubrication function, resistance to abrasion) that are necessary for the stamping step have to have their origin in the heating step resulting in a coating alloy, the above-mentioned trials also have to be repeated for different temperatures above 700°C, as claimed. The Board can accept that the skilled person, when carrying out those trials, will not go beyond temperatures which are detrimental to the coating or which can destroy it, contrary to the argument of [opponent] 04 based on B11. However, the range of temperatures to be taken into account would still have to extend to at least 950°C, mentioned in paragraphs [0023] and [0024], for obtaining the austenitization of the steel mentioned therein.

As the deformability during stamping is also one of the properties mentioned, the influence of the temperature to which the rolled sheet is heated on its deformability also has to be part of the trials to be carried out.

In view of the result of the assessment of sufficiency of disclosure […] it is not necessary to consider the question regarding the temperature of the heat treatment in the range between 700°C and the AC1 point of the Fe-C system, i.e. 723°C, or the question of whether an Fe-C-Mn alloy can be transformed at a temperature of 700°C or not.

Moreover, the trials have to be repeated for different durations during which the high temperature is applied, because figure 1 mentions a duration of between 2 and 10 minutes and the example at 950°C mentions a duration of 5 minutes, as well as for different speeds at which the temperature is increased (°C/s) during that step. These two parameters have an influence on the austenitization of the steel, which is also influenced by the steel composition […].

[3.3.4] This composition of the rolled steel in its state of total or partial austenitization, following the heating step at a temperature beyond 700°C also determines the final structure after the quenching step. As a matter of fact, the trials necessary for establishing the sufficiency of disclosure also have to take into account the search for this relationship. It is clear that quenching after partial austenitization results in any case in mixes of, for instance, ferrite + perlite + bainite or ferrite + bainite + martensite. This implies that the mechanical properties of a steel resulting from such a treatment are different from those of a steel obtained from a process including complete austenitization.

[3.3.5] As far as the quenching step is concerned, it is clear that the cooling speed and the final temperature determine the final mechanical properties of the rolled sheet and of the above-mentioned coating, i.e. the hardness of the steel vs. tensile strength. […] These parameters also have to be part of the trials to be carried out.

[3.3.6] As a consequence, the number of parameters to be observed is of at least fourteen.

Conclusions

[3.4] In view of the mechanical properties (eight or even nine) and the parameters to be followed (fourteen), in combination with the ranges to be applied to those parameters and the repetition of the trials – which are necessary for some of the mechanical properties that have to be guaranteed before and after quenching – all of it being required for carrying out the invention, the Board can only conclude that the skilled person is faced with a research programme that is so broad that it represents an excessive effort. Consequently, the description of the invention underlying claims 1 of all the requests […] is insufficient and the requirements of A 83 are not fulfilled.

It is noted that the above conclusion does not depend on the question of whether the skilled person has the required knowledge for carrying out these trials. The Board can accept that R1 represents the general knowledge of the skilled person in this technical field. The conclusion is based on the quantity of properties and the parameters to be observed therein, the ranges to be applied and the repetitions to be carried out for the different steps of the process. […]

The patent is revoked.

Should you wish to download the whole decision (in French), just click here.

The file wrapper can be found here.

NB: Le blog du droit européen des brevets also comments this decision (here).