T 0472/11 12-06-2013

1. The appeal is admissible.

2. Background

The patent concerns a sawing apparatus of a forest machine, as used in industrial tree harvesting, and which features a rotatably mounted chainsaw, with a chain guided about a guide bar under the action of a drive gear about which chainsaw can also rotate. The main idea is to use a safety system in the form of a protective wall fastened to the holder that holds the guide bar and which will therefore rotate with the saw. In the event of chain breakage this wall has the function of guiding the chain end in a controlled manner to prevent it whipping around (and causing damage or injury), specification paragraphs [009],[0010] and [0014].

3. Main Request : Added subject-matter

3.1 Claim 1 of the main request is based in first place on granted claim 5 directed to a sawing apparatus with the safety system. Amendments have been made to differentiate the claimed apparatus from that of prior art held to destroy novelty in the decision under appeal. Apart from structure and function, they specify in particular that the protective wall extends across a sector area angle of "180° or less .... starting from a point where the saw chain (6) meets the drive gear (4) and at which sector area the saw chain (6) bends around the drive gear (4)".

3.2 The only passage in the originally filed application that specifically mentions the value of 180° is the second paragraph of page 8 of the application as published which is identical to paragraph [0021] of the patent specification. The passage reads as follows:

"[The] wall 9 covers an area located at a point where the saw chain 6 is approaching the drive gear 4, meets said drive gear 4 and is curvedly positioned on top of the same. The wall 9 covers a sector area of approximately 90° to 100° starting from the meeting point, at which sector area the saw chain 6 bends around the drive gear 4. .... Together with the extension 10, the size of the sector area is approximately 110°. The aforementioned sector area is the most advantageous one, but it can be extended towards the upper side of the drive gear 4, wherein it covers an angle as wide as 180°. At the same time, however, the travel of sawdust is hindered."

The "meeting point" is that point "where the saw chain 6 .... meets the drive gear 4, see the immediately preceding sentence in the cited paragraph. "Extension" 10 refers to the part shown in figure 1 curving downwardly at and away from the lower end of the curved wall 9, see also in the bridging paragraph of pages 9 and 10 of the as filed description (specification paragraph [0023]), first sentence.

3.3 Though the above passage is not entirely unambiguous, what is unambiguously clear is that there is a "most advantageous" sector area or angle subtended by the protective wall, and that this most advantageous sector area can be extended "towards the upper side" i.e. upwardly to a value of 180° (penultimate sentence). In that case however "travel of sawdust" - taken to be out of the chain saw - is hindered (last sentence), so that this upper range of sector area values is less advantageous. The corollary of 180° as upper limit on an upward extension from the advantageous sector area angle is that the latter is a lower limit of a range of values. That range extends from the lower most advantageous value to increasingly less advantageous values up to 180°. This is the information that the skilled person derives clearly and unambiguously from the above passage disclosing the value of 180°.

The particular value of the lower limit, which is "afore-mentioned" in the sentence mentioning 180°, must follow from the preceding lines. It is thus either "approximately 90° to 100°" , mentioned several lines earlier as measured from the meeting point, or "approximately 110°" as stated in the sentence that immediately precedes it. There, however, it includes the extension part 10, which is positioned to the right of the meeting point in figure 1, and is thus measured from a different point. The cited passage is ambiguous in this regard. It is thus unclear which of the two values is meant. In addition, it is unclear whether the value of 180° is to be measured from the meeting point, or, if the sentence in which it is mentioned refers to the immediately preceding one (the more likely reading), whether it is to include the extension part 10 to the right of that point.

3.4 The amendment mentioned in section 3.1 above has no clear basis in the application as filed.

Firstly, the requirement "180° or less" sets no lower limit as compared to the original disclosure in the passage discussed above, which does. Vis-à-vis that original disclosure this amendment to claim 1 adds arrangements in which the protective wall has a sector area angle below the advantageous lower limit value of 90° from the meeting point or 110° with extension part.

Secondly, it states in an unambiguous and definitive manner that the value of 180° or less is to be measured from what corresponds to the meeting point. As noted above, the relevant passage is ambiguous in this regard. The more likely reading indeed points to the value including the extension part. This amendment adds information which has no clear and unambiguous basis in the original disclosure and thus extends beyond it.

3.5 There is no direct and unambiguous disclosure in the application documents of angles that are than less 90° or 110°, whatever the case may be, and that may even approach 0°. The Appellant cites lines 50 to 52 of the specification paragraph [0016], (identical to the paragraph bridging description pages 4 and 5 of the filed and published application), which states: "Thus, its size [i.e. of the protective wall] can be kept as small as possible and .. covers a smaller sector-shaped area...". This sentence should be read in the broader context of paragraph [0016], which discusses the advantages of having the protective wall move along with the rotating guide bar. It is "always in the correct position" in relation to the saw chain and guide bar, the movement of which can be "rather wide". The implication is that the wall can be dimensioned to cover a smaller angle than if it also had to allow for that wide angle. Naturally, its angular extent must still be large enough for it to fulfil its primary function of preventing the whip-like movement of broken chain. "As small as possible" is to be understood in that limited context, and certainly does not offer a basis for angle values approaching 0° where clearly there would be no protective effect.

As to claim 9 (as filed and as granted) also cited by the Appellant, this defines an even narrower angular range with a lower limit of 100° and up to 120°. This does not provide any basis for the absence of any lower limit, let alone that the value of 180° should be measured from the meeting point.

3.6 The Board concludes that the amendments to claim 1 of the main request add subject-matter that extends beyond the original disclosure, contrary to the requirements of Article 123(2) EPC.

4. Auxiliary Request 1 : Admissibility

4.1 Auxiliary request 1 was first filed at the oral proceedings before the Board, well after filing of the grounds of appeal. The request thus amounts to an amendment to the appellant's case in the sense of Article 13 of the Rules of Procedure of the Boards of Appeal. Under paragraph (1) of that article the Board has discretion in admitting such amendments. It shall exercise that discretion "in view of inter alia the complexity of the new subject-matter submitted, the current state of the proceedings and the need for procedural economy". Indeed any amendments that the parties cannot reasonably be expected to deal with without an adjournment should not be admitted, Article 13(4) RPBA.

An approach frequently adopted by the Boards when exercising their discretion in admitting amendments filed shortly before or in the course of oral proceedings can be summarized as follows: unless good reasons exist for filing amendments so far into the procedure - this may be the case when amendments are occasioned by developments during the proceedings -, they are only admitted at such a late stage if they are clearly or obviously allowable, see the Case Law of the Boards of Appeal, 5th edition, 2006, sections VII.D.14.2.1 and 14.2.3 and the case law cited therein. This means that it must be immediately apparent to the Board, with little or no investigative effort on its part, that amendments successfully address the issues raised without giving rise to new ones, see for example T 0087/05, reasons 2.

4.2 The last but one feature of claim 1 of auxiliary request 1 is amended with respect to that of the main request by adding the value of 90° and specifying that the angle of 180° includes an extension at the first end of the protective wall. The claim however retains the wording that the angle of 90° to 180° starts from the meeting point of chain and gear. Not only do the amendments not address the second point mentioned in section 3.4 above, in conjunction with the inclusion of the extension the claim now allows for an arrangement where the protective wall with extension starts from the meeting point. In reference to figure 1 of the patent this corresponds to a configuration in which the element 9 is rotated clockwise until the downwardly curved end of the extension 10 lies directly below the meeting point, i.e. on the dashed vertical line in the figure. There is no apparent basis in the original disclosure for such an embodiment.

4.3 Not only do the amendments to claim 1 of the auxiliary request fail to fully address the issue of added subject-matter noted in relation to claim 1 of the main request, they appear to give rise to further objection under that heading. The request is therefore not clearly allowable. For this reason the Board decided to use its discretion not to admit this request in the proceedings, pursuant to Article 13(1) RPBA.