Germany: lack of inventive step due to accepted disadvantage (FCJ X ZR 50(16 – Belt tightener)

In Germany, too, it has become established to assess the inventive step on the basis of the problem-solution approach. Advantages of the invention on the one hand and disadvantages in the prior art, on the other hand play a central role. It is assumed that the skilled person would like to avoid known disadvantages. The FCJ has recently addressed the following question: Can a solution be considered non-obvious and therefore inventive if it involves foreseeable disadvantages?

The claim of the patent in suit concerns a "belt tensioner drive", which consists essentially of two worm gears connected in series. Each of the two worm gears has a 90 ° deflection, so that the drive axle and output shaft of the belt tensioner drive are ultimately parallel to each other.

The nullity attack is based mainly on two references: one (D3) shows the exact same sequence of two worm gears in a retractor. However, this gear is used for the purpose of a certain loosening of the belt. Compared to the patent in dispute, the prior art just differed with respect to the purpose.

The other reference (D2) concerns a belt tensioner, but with a combination of crown gear and worm gear. That is, while the invention used a worm gear in the first place, the citation instead used a crown gear.

The German Federal Patent Court annulled the patent. It is known to the person skilled in the art that crown gear drives have the disadvantage that they produce noises. At the same time it will be clear to the person skilled in the art that other deflection gears, such as e.g. worm gears do not have this disadvantage. The skilled person, therefore, had reason to look for transmission solutions that do not have the disadvantage. Since the citation D2 already envisaged a worm gear as the second gearbox, it was quite possible to expect from a person skilled in the art that he would also use a worm gear as the first gearbox.

By contrast, the patent proprietor appealed to the Federal Court of Justice (FCJ). However, the FCJ confirmed that the patent in suit is not inventive. In its reasoning, the FCJ inter alia states the following.

The advantage of the worm gear, namely a self-locking against a torque from the belt reel to the electric motor, is known from the seatbelt tensioner.

In addition, the D3 shows the person skilled in the principle of using two worm gears as 90 ° -gear box in order to achieve a low noise parallel arrangement of belt reel and electric motor. The skilled person can recognize that the arrangement of an electric motor, two worm gears and a belt reel, can achieve the function of a belt tightening. All you have to do is to change the electric motor to create a different direction of rotation and thus a belt tightening instead of a slack.

Since the skilled person was aware of the disadvantageous noise development of crown gear drives, he had reason to further develop the belt tensioner known from D2 in such a way that the noise emissions are reduced. For this he received suggestions in the prior art according to D3, how such an improvement could be realized concretely.

The proprietor's objection namely that the use of two instead of just one worm gear results in a higher gear reduction and therefore the patented application was not obvious, does not apply. The fact that the electric motor has to rotate higher in two worm gears, is not at all mentioned in the patent. Such an issue is neither addressed in any way as a difficulty, nor is it stated in the patent how this disadvantage should be overcome. Obviously the patent tacitly accepts this disadvantage.

If the solution proposed by the inventor ignores the existing disadvantages or difficulties and simply accepts them, then it can not be argued that the person skilled in the art would have recognized these difficulties and would not have considered using the corresponding disadvantageous solution.

As a further objection to the obviousness of the invention, the patent proprietor has submitted the following: The need for a self-locking effect is mentioned in the cited prior art and it is addressed by proposing various other measures differing from the use of a second worm gear. It was therefore obvious for the expert to choose one of these other measures for noise reduction.

This objection does not apply according to the FCJ as well. If several alternatives are considered by the skilled person to solve a problem, several of them may be obvious. In this case, it is fundamentally irrelevant which of the solution alternatives is considered by the skilled person to be the first one (that is, the more obvious one).