In a recent post we have seen a decision examining the credibility that a given problem had indeed been solved. Once it is established that the problem has been solved, it remains to be demonstrated or at least made credible that the claimed features are at the origin of the effect.
[4.2.5] The Board agrees with the Respondents that the extruders used in the examples of the patent in suit show improved efficiency when compared with those of D2.
There is however no evidence that this improvement is due to the distinguishing feature of the claim, namely the number of thread starts. On the contrary the comparison between experiments 10 and 11 discussed above undisputedly question that this is the case.
[4.2.6] In addition to the results in the patent, the Respondents relied during the oral proceedings on paragraph  of the specification in order to establish that an increase of performance has been achieved. According to this paragraph it was possible to dramatically increase the performance of an extruder when used in the manufacture of ice cream by:
(a) operating with a pitch angle which is outside what has been used up until now in the manufacture of ice cream,
(b) operating with screws which have more than one thread start, whereas up until now screws with only one thread start have been disclosed, and
(c) operating with extruders which are much shorter than what has been used up until now.
[4.2.7] The Board notes: that feature (a) is not a distinguishing feature of the claimed extruder; that the results in the Table of the patent question the affirmation of the Respondents that feature (b) is responsible for the increased performance of the extruder; and that feature (c) is not a feature of the subject-matter of Claim 1 of the main request.
With respect to feature (b) the Board notes furthermore that, in the absence of supporting evidence, an improved performance of an extruder having a screw with more than one thread start over an extruder with a single threaded screw is not per se credible, because given the complexity of the parameters influencing the rheological properties in an extruder, this feature by itself can in all probability not be assumed to influence the cooling performance in the desired fashion independently of other parameters.
The Board thus concludes that an improvement of the efficiency of the extruder relating to the distinguishing feature of the invention is not derivable from the patent in suit.
Reformulation of the problem and its solution
[4.3.1] In view of the above, an improvement of the energy efficiency of the extruders according to Claim 1 cannot be acknowledged as the objective technical problem underlying the invention as claimed in the main request. As a consequence, the problem has to be reformulated in a less ambitious manner, not involving such improvement.
[4.3.2] The objective problem can thus be reformulated as the provision of further screw extruders for the manufacture of ice cream.
[4.3.3] It is not disputed that this less ambitious problem is solved by the claimed single screw extruders having between 2 and 6 thread starts according to Claim 1 as it is an alternative design when compared to that of D2.
[4.4.1] The question which remains to be decided is whether this solution involves an inventive step, that is to say, if in view of the reformulated problem the claimed subject-matter is obvious or not.
[4.4.2] In the absence of an improvement of the efficiency of the extruder, the use of a screw extruder with more than one thread start is regarded by the Board as obvious for the skilled person and therefore lacking inventive step.
[4.4.3] The reason for this conclusion is that it is undisputed that multiple thread starts are well known in the design of screw extruders (see, for instance, D40). Moreover extruders with multiple thread starts have already been used in the manufacture of ice creams, for instance in Example 1 of D7.
[4.4.4] As this finding was not disputed by the Respondents, who even admitted during the oral proceedings that if the improvement of the efficiency of the extruder was not accepted, there was no inventive step in the use of a screw with multiple thread starts, no further comments are needed.
[4.5] For the reasons set out above the subject-matter of Claim 1 of the main request lacks inventive step.
Normally this less-ambitious-problem situation precedes the revocation of the patent for lack of inventive step. In the present case, however, the third auxiliary request (claiming a screw extruder with a screw having between 2 and 6 thread starts and a screw length/screw diameter ratio of between 2 and 10) was found to involve an inventive step, not because it solved a more ambitious problem, but because use of such screws was not known or suggested in the prior art.
To read the whole decision, please click here.