T 1556/06 24-06-2008

Reasons for the Decision

1. The appeal is admissible.

2. Patent as granted

2.1 Document E7 can undisputedly be regarded as an appropriate starting point for the assessment of inventive step. It discloses a method of friction stir welding comprising using a rotating friction stir welding tool to weld a workpiece comprised of a friction stir weldable material (see Fig. 2 on page 42).

The subject-matter of claim 1 differs from this known method by simultaneously removing excess heat produced by the use of the friction stir welding tool,

whereby the removal of heat produces a smoother weld surface, without machining the weld surface, at a faster rate.

2.2 The technical effect of the method step of simultaneously removing excess heat produced by the use of the friction stir welding tool is, as stated by claim 1 itself, that of producing a smoother weld surface, without machining the weld surface, at a faster rate. As pointed out by the appellant/opponent, the latter definition of claim 1 is a relative expression and does not constitute, in the absence of specific terms of reference, any clear limitation for the claimed subject-matter. According to the description of the patent in suit (see par. [0005]), the step of removing excess heat prevents the softened material from adhering to the rotating pin and shoulder of the friction stir welding tool. Adherence of material would cause a rough weld surface or even render continuing the weld impossible (see col. 1, line 52 to col. 2, line 6, of the patent in suit). Therefore, the above-mentioned relative expression of claim 1 is to be read to imply that the step of removing excess heat allows for an increase in the welding rate whilst obtaining a satisfactory weld surface.

Accordingly, the objective technical problem solved by the distinguishing features can be seen in how to increase the welding rate whilst obtaining a satisfactory weld surface.

2.3 The skilled person faced with the problem of increasing the welding rate would immediately appreciate that this would involve increasing the heat input to the workpieces. The skilled person would also appreciate that, for a given friction stir welding tool, an increase of the heat input to the workpieces would result in increased heat input to the tool itself: not all the additional heat generated by the friction between the tool and the workpieces would be taken up by the workpieces but a part thereof would be taken up by the tool itself. The skilled person would then obviously recognise that at high welding rates, and thus high heat input, overheating of the tool would present a problem and thus when increasing the heat input would obviously consider providing additional means for dissipating the heat taken up by the tool, in particular cooling means. It is indeed well known in the general field of metal joining processes to cool welding tools in order to prevent overheating. This is in particular exemplified by E1, which relates to the neighbouring technical field of friction welding by means of friction wheels (see col. 1, lines 22 to 42). According to E1 the friction wheels are cooled to prevent overheating (see col. 4, lines 39 to 42). Therefore, the skilled person would obviously consider modifying the method of friction stir welding according to E7 by cooling the tool, thereby arriving at a friction stir welding method in which, in accordance with the wording of claim 1 of the patent in suit, excess heat produced by the use of the friction stir welding tool is simultaneously removed. Since the skilled person would increase the welding rate only by as much as would still allow a satisfactory weld to be obtained, in particular a satisfactory weld surface, in doing this he would necessarily arrive at a method according to claim 1 of the patent in suit.

2.4 Even assuming that the feature of claim 1 according to which the removal of heat produces a smoother weld surface, without machining the weld surface, at a faster rate, should be read to mean that by removing excess heat a weld surface is obtained which is smoother than the weld surface which is obtained when carrying out a "reference" method, namely a friction stir welding method carried out under same conditions but without removing heat and at a slower rate, the above conclusion remains unchanged. As submitted by the appellant/patent proprietor during the oral proceedings before the Board, a weld surface which is produced when removing heat is always smoother than a weld surface obtained under the same conditions but without removing heat, independently of the workpiece material. Therefore, for the same welding rate, a friction stir welding method in which heat is removed always leads to a smoother weld surface than the same friction stir welding method in which heat is not removed. Clearly, this result will be unchanged if the welding rate is only slightly reduced and the cooling is carried out efficiently. In the absence of any specific indication, the welding rate for the reference method can be arbitrarily defined. Accordingly, for the method of friction stir welding according to E7 modified by cooling the tool, it is always possible to find a reference friction stir welding method in which the tool is not cooled and the welding rate is slightly lower and which produces a weld surface which is less smooth.

2.5 Therefore, the subject-matter of claim 1 as granted does not involve an inventive step (Article 100(a) and 56 EPC).

3. Patent as maintained

3.1 The documents E9 to E12 filed in the appeal proceedings

These documents were said by the appellant/opponent to have been filed in response to the amendment made to the patent in the amended form allowed by the opposition division, consisting of introducing into claim 1 the feature taken from the description according to which the workpiece is comprised of a non-extrudable aluminium alloy.

Documents E9 and E10 show that hard aluminium alloys of the 2000 and 7000 series can be extruded (E9: page M651-2; E10: page 3, first par.). According to the patent in suit, non-extrudable alloys are exemplified by the 2024, 7075, 2014 and 2090 alloys, i.e. alloys belonging to the 2000 and 7000 series. Since E9 and E10 are relevant in assessing the meaning of the feature "non-extrudable aluminium alloy", they effectively constitute a reaction to the amendment made. For this reason the Board decided that E9 and E10 were not to be disregarded for reasons of late-filing.

Since E11 relates to an extrusion die and as such is not prima facie relevant to the claimed subject-matter, and E7 discloses essentially the same subject-matter of E12 and is not more relevant than the latter (E7 and E12 in fact have many passages in common), the Board decided pursuant to Article 114(2) EPC not to admit E11 and E12 into the proceedings.

3.2 Clarity

The amendment made by including in claim 1 the term "non-extrudable aluminium alloy", which is taken from the description of the patent in suit (see e.g. col. 1, line 45), introduces a lack of clarity, contrary to Article 84 EPC. Although it is generally known that some aluminium alloys are easier to extrude than others (see in particular E9, page M651-2, last paragraph, where it is stated that there are soft alloys which are well suited for the extrusion process and hard alloys which are less suited), there is no recognized standard for classifying aluminium alloys as "extrudable" and "non-extrudable". In fact, alloys of the series 2000 and 7000, which are included in the examples of non-extrudable aluminium alloys given in the patent in suit (see col. 1, lines 48, 49 and col. 4, line 20), can be extruded, as shown by documents E9 (page M651-2) and E10 (page 3, first paragraph), it being noted that E9 refers in general to a method of manufacturing a workpiece by extrusion. A skilled person might possibly classify an aluminium alloy as "extrudable" or "non-extrudable", as submitted by the appellant/proprietor. However, he would do so on a subjective basis and not on an objective basis. Accordingly, since it is not clear what aluminium alloys can be regarded as being "non-extrudable" on an objective basis, the claim does not clearly define the matter for which protection is sought (Article 84 EPC).

4. Auxiliary requests

The auxiliary requests filed with the letter dated 23 May 2008 constitute an amendment to the appellant/patent proprietor's case after it filed its grounds of appeal and therefore pursuant to Article 13(1) of the Rules of Procedure of the Boards of Appeal may only be admitted and considered at the Board's discretion.

4.1 Auxiliary requests I to IV

4.1.1 Claim 1 according to auxiliary requests I to IV includes the feature of (the wording added is in italics) reducing the degree of adherence between the tool and the softened material by simultaneously removing excess heat produced by the using of the friction stir welding tool. The wording added is taken from the description of the patent in suit (see col. 3, line 56 to col. 4, line 3).

During the oral proceedings the appellant/patent proprietor submitted that the intended result, namely the achieving of a smoother weld surface at a faster rate, was the direct result of the step of removing excess heat. In fact, the disclosure of the patent in suit does not allow any different conclusion. As stated in par. [0005] of the description (lines 36 to 38), "excessive heat causes the softened material to adhere to the rotating pin and shoulder of the friction stir welding tool…". It is therefore not clear what further limitation is introduced into claim 1 by including the above-mentioned wording. This applies to claim 1 of all requests I to IV.

4.1.2 In view of this, the Board decided not to exercise its discretion pursuant to Article 13(1) RPBA to admit the auxiliary requests I to IV.

4.2 Auxiliary request V

4.2.1 Compared to claim 1 as granted, claim 1 is restricted to friction stir welding of a workpiece made of one of the alloys 2024, 7075, 2014 and 2090. Since E7 already discloses friction stir welding of workpieces made of the aluminium alloy 2014 (see page 43, left col., 3rd and 4th par.), the subject-matter of claim 1 is distinguished from the method of E7 by the same distinguishing features as with claim 1 as granted. Therefore, the subject-matter of claim 1 of this request appears to lack an inventive step for the same reasons given above in respect of the subject-matter of claim 1 as granted (see point 2 of this decision).

4.2.2 Since claim 1 is prima facie not allowable for the same reasons as for claim 1 as granted, the Board decided not to exercise its discretion pursuant to Article 13(1) RPBA to admit the auxiliary request V.

4.3 Auxiliary request VI

Claim 1 of this request is amended over claim 1 as granted by including the feature taken from the description (see col. 6, lines 48 to 58 of the patent in suit) according to which the removal of excess heat consists of cooling by a coolant flow, wherein the coolant flow is controlled to avoid overcooling. As already explained above in respect of claim 1 as granted, the skilled person would consider it as obvious to cool the friction stir welding tool used in the method according to E7. Considering that cooling using a coolant flow is a matter of normal design procedure and as such an obvious feature, and that the fact that cooling should not be so intense such as to interfere with the welding process appears to be self-evident, the amendments made do not appear prima facie such as to introduce inventive subject-matter over that of claim 1 as granted. On this ground the Board also decided not to exercise its discretion pursuant to Article 13(1) RPBA to admit also the auxiliary request VI.

4.4 Auxiliary request VII

4.4.1 Auxiliary request VII includes claims 1 to 3 only. It constitutes a clear limitation of the patent in the form as maintained by the opposition division since these claims 1 to 3 correspond to claims 7 to 9 as maintained. The Board does not see any reasons not to admit this request. Nor did the appellant/opponent object to its admissibility.

4.4.2 In contrast to independent claim 1 of the patent as maintained, which is directed to a friction stir welding method, claims 7 to 9 as maintained are directed to a friction stir welding tool, whereby claims 7 and 9 are independent claims. The opposition division stated that the first auxiliary request met the requirements of the EPC, but gave reasons as regards inventive step only for claim 1. Since claims 7 and 9 as maintained define inter alia specific cooling means for the friction stir welding tool, it is not possible to directly apply to these claims the arguments of inventive step given in respect of claim 1.

4.4.3 It follows from the above that the issue of inventive step of claims 1 and 3 of the auxiliary request VII essentially represents a fresh case. Under these circumstances the Board considers it appropriate, in accordance with Article 111(1) EPC, to remit the case to the opposition division for further prosecution. By this means both appellants have the opportunity to have the case further examined with respect to inventive step without loss of an opportunity to appeal.

5. Reimbursement of the appeal fee

5.1 Rule 103(1) EPC provides for reimbursement of appeal fees in a case where the Board of Appeal deems an appeal to be allowable, if such reimbursement is equitable by reason of a substantial procedural violation. In the present case the appeal of the patent proprietor has not been allowed, and therefore reimbursement of the appeal fee cannot be ordered.

5.2 Notwithstanding the above conclusion, the Board considers it appropriate to clarify the issue of the alleged substantial procedural violation.

5.2.1 It is not in dispute that the purpose of the PowerPoint presentation was only to enable the patent proprietor better to present its arguments, not to give evidence.

5.2.2 Article 116 EPC guarantees a party the right to oral proceedings. The basic purpose of such oral proceedings is to give the party an opportunity to present its argument orally (T 1110/03, para. 3.2). As established by Boards of Appeal case law, a refusal to allow a party to present its arguments orally is thus capable of amounting to a substantial procedural violation.

5.2.3 However, the essence of an oral presentation is in the Board's view just that: presentation of arguments by word of mouth. A PowerPoint presentation is not by itself an oral presentation in this sense. Decision T 1110/03, mentioned by the appellant/patent proprietor, explains some of the ways in which it differs from and is inferior to an oral presentation.

5.2.4 In the Board's view, Examining and Opposition Divisions, and Boards of Appeal, have a discretion as to the way oral proceedings are conducted, particularly having regard to the need for procedural economy and fairness to the parties. This discretion enables the competent tribunal to allow a party to use flip charts, PowerPoint presentations, etc., as an aid to oral presentation, or to refuse to allow the use of such means.

5.2.5 Any discretion must, of course, be exercised in a judicial manner and having regard to the interests of justice, particularly, in the present context, having regard to the right of a party to present its arguments orally.

5.2.6 It is perhaps possible to imagine a case in which a party would objectively be unable to present its arguments adequately without the aid of a PowerPoint presentation. Usually, however, the presentation of materials by a PowerPoint presentation is simply an alternative way of presenting written materials or drawings and, as such, belongs to the written stage of the proceedings (see T 1110/03, para. 3.2). Indeed, T 1122/0l (also cited by the appellant/patent proprietor) makes it clear that the content of a PowerPoint presentation should have been notified in advance of the hearing. This means that usually a party will be fully able to present its arguments orally by reference in the ordinary way to such materials or drawings. The refusal to allow a party to supplement its arguments by reference to a PowerPoint presentation therefore usually cannot amount to a substantial procedural violation because the party's right to present its arguments orally will not have been violated.

5.2.7 In the present case, the patent proprietor was given the opportunity to present its arguments orally, and indeed did so. The nub of the grounds of appeal is that if the appellant had been allowed to give a PowerPoint presentation, one of the prior art documents (E8) would not have been incorrectly interpreted by the Opposition Division. However, nothing in what was submitted by the appellant/patent proprietor explains how a proper understanding of E8 could have been obtained only with the help of the PowerPoint presentation as opposed to a normal oral presentation with reference to the patent and prior art.

5.2.8 In conclusion, the Opposition Division had a discretion to allow or not allow the patent proprietor to use a PowerPoint presentation. There is nothing to suggest that this discretion was exercised against the patent proprietor incorrectly, in particular in such a way as to infringe its procedural rights arising under the EPC, in particular Article 116 EPC. Accordingly, no substantial procedural violation was made by the Opposition Division.

6. Apportionment of costs

It is clear that additional costs will be occasioned by a remittal. However, the Board cannot see an abuse of procedure in the appellant/patent proprietor's behaviour: the seventh auxiliary request corresponds to the patent in the form maintained by the opposition division, amended only by way of deletion of the method claims 1 to 6 in reaction to the objections raised by the appellant/opponent and the Board during the appeal proceedings (see in particular above point IV). Therefore, there are no reasons of equity which in accordance with Article 104(1) EPC would justify a different apportionment of costs. The appellant/opponent's request cannot therefore be allowed.