T 0882/14 03-05-2016

Claim 1 as granted

1. Novelty (Article 100(a) EPC, Article 54(3) EPC)

1.1 Document D1 constitutes state of the art under Article 54(3) EPC and is prejudicial to the novelty of the subject-matter of claim 1.

1.2 D1 shows a vehicle having a braking system (Figure 1, description page 9) comprising a braking demand input device ("Bedienelement 2") as further specified in two embodiments. In the first embodiment, the input device is realised by an operating panel ("Bedientafel", see description page 3, second paragraph, to page 4, fifth paragraph; also defined in claims 2 to 9), whereas the second embodiment relates to a hand brake handle for inputting a driver braking demand (description page 4, last paragraph onwards; also claims 10 to 15).

As regards the embodiment with an operating panel, the opposition division held that the amount of extra braking force was not predetermined but rather set by the operator in accordance with circumstances, and that the operating panel did not correspond to the braking demand input device but to a further input device. The board does not share this view.

1.3 The vehicle according to D1 (page 1, first paragraph; also claim 1) comprises an electronic braking control unit (integrated in the modulator 1 in Figure 1) and a switch implicitly connected to the electronic braking control unit, in order to activate a so-called "Fertiger-Bremsfunktion", which causes the brake actuator assembly to apply a low level braking force, i.e. corresponding to the contested patent in which the switch is defined by the same function. Therefore, features (f) to (i) are known from D1. According to a first embodiment in D1 (see pages 3, 4; also claims 2 to 9), an operating panel allows the driver to enter - via number keys - a desired braking pressure (i.e. a driver's braking demand deviating from the standard brake pressure which would be otherwise applied), which is received by the electronic braking control unit controlling the brake actuator assembly, as required by features (a) to (e). The operating panel also comprises arrow keys which allow the driver to increase sequentially the braking pressure controlled by the electronic control unit as described above, i.e. to increase the low level braking force. The term "sequentially" used in combination with the arrow keys implies that the brake pressure might be increased "in steps", i.e. by a predetermined amount as required by feature (j).

1.4 The board therefore finds that the operating panel in D1 represents a braking demand input device within the meaning of claim 1. Claim 1 does not contain any limitation to only one single operating option, since it specifies a braking demand input device which is at the same time operable by a driver to generate a braking demand signal and also to modify the brake operation signal so as to increase the low level braking force by a predetermined amount. Both the number and arrow keys in D1 formed part of the same device, so the board does not agree with the respondent that separation of functions in D1 made the two sets of keys two different devices. Moreover, due to the braking demand input device of feature (a) and the associated function according to features (b) to (e) remaining rather unspecific, the wording of granted claim 1 does not rule out that the braking demand input device performs the same function as specified later by features (f) to (i), i.e. the "Fertiger-Bremsfunktion" providing a low level braking force, and also the function of modifying the low level braking force as required by feature (j).

Auxiliary request

2. Admissibility

Independent claim 1 of the auxiliary request results from a combination of claims 1 and 2 as granted, which is not open to an objection under Article 84 EPC, and no ground for opposition under Article 100(c) EPC was raised against the granted patent. Moreover, an adapted version of the description was filed during the oral proceedings. The board therefore considers the auxiliary request admissible. This was, in fact, not disputed.

3. Sufficiency of disclosure

The appellant raised several objections under Article 100(b) EPC against claim 1 as granted, which were maintained with regard to claim 1 according to the auxiliary request.

3.1 A first objection relates to feature (d) ("which generates an appropriate brake operation output signal..."), in particular with regard to the term "appropriate". According to paragraph [0016] of the patent specification (page 5 of the application as filed), the braking demand signal is transmitted to the ECUs of the electronic brake system "which use the information stored in their memory to generate an appropriate electrical brake operation output signal", i.e. the skilled reader would understand that the braking demand signal represents an input to the ECUs which generate, according to an algorithm, a command value or output signal for actuating the brakes. The term "appropriate" merely expresses that the brake operation output depends on or takes into account the braking demand signal, which corresponds to how conventional, prior art, electronic braking systems operate. Accordingly, it is not left open "in relation to what" the signal is "appropriate", as alleged by the appellant. Moreover, feature (d) also recites "for what" the signal is "appropriate" or "suitable for", namely "for transmission to at least one brake actuator".

3.2 In the board's judgment, the use of the indefinite article for the "brake operation output signal" in features (d) and (h) is justified already by the fact that both signals are generated in response to different inputs to the electronic braking control unit, i.e. either in response to the brake pedal forming the braking demand input device (feature (a) viewed together with the characterising feature) or in response to operation of the switch (feature (f)). Even assuming that the brake operation output signal was transmitted via a single output port of the control unit, the board agrees with the respondent that "signals" are - in contrast to a device - of transient character varying in time, so that the indefinite article "a" is correctly used in features (d) and (h) to denote the transmission of two different signals or information values to the brake actuator assembly.

As regards the term "the brake operation signal" in feature (i), which deviates from the term "a brake operation output signal" mentioned previously, and use of the definite article, the board cannot see that the skilled person would not be able to implement the invention on the basis of the disclosure of the specification as a whole. Paragraph [0018] of the patent specification describes that the operation of the switch causes a brake operation output signal to apply a low level braking force, so a clear link exists between features (h) and (i). Therefore, on a reasonable interpretation of claim 1 in light of the disclosure of the specification, it can be excluded that "the brake operation signal" of feature (i) might represent a third signal different from the signals defined in features (d) and (h). Moreover, as already set out above, the brake operation output signals according to features (d) and (h) are not identical, transmitted either in response to operation of the brake pedal or operation of the switch. Therefore, the board cannot identify any reason to assume that no emergency braking as described in paragraph [0021] would be possible, as alleged by the appellant, in particular because operation of the brake pedal still allows the driver to override application of a low level braking force.

An objection to omission of the term "output" in the term "the brake operation signal" of feature (i) amounts to a clarity objection to a granted feature, which is not admissible (cf. decision G 3/14).

3.3 Contrary to the assertion of the appellant, it is clear from the patent specification as a whole, and also from the wording of feature (j) itself, that it must be possible to modify the low level braking force. As set out above, the low level braking force according to feature (i) is disclosed as being linked to the brake operation output signal of feature (h).

3.4 The term "low level" in claim 1 represents a relative term characterising the braking force which was already present in claim 1 as granted, so an objection with regard to clarity is not admissible (G 3/14).

Moreover, on the basis of the disclosure in the patent specification (see paragraph [0004]), the skilled person would know how to carry out the invention. The low level braking force is provided to counteract the reaction force of the road-laying machine, i.e. to prevent speeding up of the vehicle when the road-laying machine is in operation. Such definition of the low level braking force by its result to be achieved takes into account that the actual value of the low level braking force has to be determined dependent on the type of vehicle and its mass. The board does not see any reason to doubt that the claimed invention is sufficiently disclosed to enable a skilled person to put it into practice without undue burden or experimentation.

3.5 The appellant alleges that the objective to be achieved by the invention to maintain vehicle speed at a constant level would not be reached by increasing the low level braking force under certain driving conditions, in particular when running up a slope, under head wind conditions, or when the vehicle load decreased during the asphalt-laying operation, where the braking force had to be reduced to maintain a constant vehicle speed. However, since the claimed invention is only concerned with the problem of speeding up (see paragraph [0004] of the patent specification), the board finds that driving situations which would lead to a vehicle slowing down, i.e. relating to a different problem, are irrelevant when it comes to the assessment of sufficiency of disclosure.

3.6 Since the wording of claim 1 does not recite any parameters or ranges, the board finds that there is no issue with carrying out the invention over the whole range claimed, as alleged by the appellant. The skilled person has at least one embodiment available in the description of the patent specification, and the board has no doubt that on this basis the subject-matter of claim 1 is disclosed in a manner sufficiently clear and complete for it to be carried out. Moreover, the invention is not simply specified by the problem to be solved, i.e. maintaining the vehicle speed at a constant level. The mere fact that the invention as defined by the wording of claim 1 might not work satisfactorily under all driving conditions, as discussed above, is not a matter of sufficiency of disclosure. It simply means that further improvements of the claimed invention might be conceivable.

4. Inventive step

4.1 Starting from document D8 as the closest prior art, the features of the pre-characterising portion of claim 1 are known from D8. This was not disputed.

4.1.1 The problem to be solved can be regarded as providing a vehicle with improved comfort of operating the braking system in order to maintain a constant vehicle speed. Even if the board were to follow the appellant's argument that the skilled person would have considered D9 or D4, since these documents also mention the problem of improving the operating comfort, it would not be convinced that starting from D8 the skilled person would have arrived at the claimed subject-matter in an obvious manner.

4.1.2 As a matter of fact, both D9 and D4 show a service brake and a separate sustained action brake, e.g. in form of a retarder or an engine brake, which are controlled - in common - by operating the brake pedal, whereas D8 shows that the service brake, controlled via the brake pedal, might be used to implement the function of a road finisher brake, which requires a separate switch to be operated in advance.

4.1.3 According to D9, the sustained action brake is activated by slightly tipping the brake pedal, and a retarder braking force can be increased by a predetermined amount by operating the brake pedal for a longer time. The board has serious doubts whether the skilled person would combine this teaching with the road finisher brake disclosed in D8, which does not rely on a separate retarder but on the vehicle's service brake.

Even assuming that the skilled person were to have taken the teaching of D9 into account, the board finds that the skilled person would then have applied the control of a low level braking force as taught by D9, i.e. the brake pedal would be used for activating and also for modifying the low level braking force. However, this would result in a braking system which does not require an additional switch to initiate transmission of a brake operation output signal to the brake actuator assembly, as required by features (f) to (h) of claim 1. Irrespective of whether the skilled person would also dispense with the additional sustained action brake used in D9 for providing a low level braking force, the skilled person therefore would not arrive at the subject-matter of claim 1 according to the auxiliary request, which clearly distinguishes between two input devices, namely a brake pedal (feature (a) and characterising feature) and a switch (feature (f)).

4.1.4 For the same reasons as set out above, a combination of D8 with D4 would not lead to the subject-matter of claim 1, and it can be left open whether D4 discloses that a low level braking force is increased by "a predetermined amount". According to D4, an additional deceleration - determined by the number of consumer circuits ("Verbraucherkreis") to be added - could also be provided by tipping the brake pedal, without requiring a separate switch which causes the electronic braking control unit to transmit a brake operation output signal to the brake actuator assembly.

4.1.5 The board therefore concludes that, even assuming that the person skilled in the art would consider taking into account the teaching of D9 or D4 when starting from D8 as the closest prior art, he would not arrive in an obvious manner at the subject-matter according to claim 1.

4.2 Starting from document D4 as the closest prior art, the parties agreed that D4 does not show a low level braking force applied by the brake actuator assembly as specified in feature (i). Moreover, as argued by the respondent, D4 does not disclose a switch as required by features (f) to (h), i.e. a switch which is operable to transmit a signal to the electronic braking control unit which causes the electronic braking control unit to transmit a brake operation signal to the brake actuator assembly.

Since the low level braking force in D4 is not provided by the brake actuator assembly, but by switching on the compressor, i.e. an additional consumer circuit, the problem to be solved by the distinguishing feature is considered to be to provide an alternative mechanism for applying a low level braking force.

D8 shows a low level braking force applied by the service brake in order to prevent a road finisher from departing from the vehicle. However, the board is not convinced that the skilled person would be tempted to apply this very specific operation of the service brakes with low braking forces, which is only permitted for low speed conditions and which has to be authorised by operating a switch, to a system controlling and limiting vehicle speed as known from D4. The speed limitation in D4 is not restricted to low vehicle speeds, so it cannot be guaranteed that the service brake could be operated with minimal wear of the friction linings.

Therefore, the board concludes that the subject-matter of claim 1 according to the auxiliary request is also inventive over a combination of D4 with D8.

4.3 Dependent claims 2 to 5 concern particular embodiments of claim 1 and are therefore likewise allowable.

5. The board comes to the conclusion that the claims according to the sole auxiliary request are found to meet the criteria of patentability. Moreover, the description has been brought into conformity with the amended claims.