T 1102/13 09-03-2017

Summary of Facts and Submissions

I. European patent No 1 974 101 (in the following: "the patent") concerns a sheet pile in double-T form which has a V-shaped groove for coupling to a connection profile.

II. The patent as a whole was opposed by opponents 1 and 2 on two grounds of Article 100(a) EPC (lack of novelty and lack of inventive step).

III. The opposition division decided to reject the oppositions.

IV. This decision was appealed by both opponents (here appellants 1 and 2).

V. With the summons to oral proceedings, the Board sent a communication pursuant to Article 15(1) of the Rules of Procedure of the Boards of Appeal (RPBA) indicating its preliminary opinion of the case.

VI. Oral proceedings before the Board were held on 9 March 2017, for the course of which reference is made to the minutes. As announced by letter of 9 January 2017, duly summoned appellant 2 was not present at the oral proceedings. Despite being duly summoned, appellant 1 failed to appear.

VII. Requests

The appellants requested in writing that the decision under appeal be set aside and the patent be revoked.

The patent proprietor (here respondent) requested that the appeals be dismissed (main request), alternatively, that the patent be maintained in amended form on the basis of one of the sets of claims filed as auxiliary requests 1 and 2 with letter of 27 November 2013.

VIII. Claims of the patent proprietor's main request (claims as granted)

Independent product claim 1 is directed to the following subject-matter (the feature breakdown was relied on in the decision under appeal and used by all parties):

1.1) Steel sheet pile in double-T form, comprising

1.2) a web and

1.3) two flanges,

1.3.1) wherein each flange has an inner side facing the web, an outer side facing away from the web, and two longitudinal edges; and

1.3.2) a coupling means for a connection profile is provided along at least one longitudinal edge of at least one flange end,

characterized in that

1.4) the coupling means is formed by a milled groove,

1.4.1) which extends in the outer side of the flange along the at least one longitudinal edge and

1.4.2) has a substantially V-shaped cross section

1.4.3) with an opening width (b) lying within the range (0.5·e) <= b <= (1.5·e) and

1.4.4) with a depth (t) lying within the range 10 mm <= t <= (0.5·e),

1.5) where (e) is the thickness of the flange in the direct vicinity of the groove.

Independent method claim 15 is directed to the following subject-matter:

15.1) Method for producing a sheet pile in accordance with any one of the preceding claims comprising the steps of:

15.2) hot-rolling a double T-profile

15.3) comprising a web and two flanges, wherein each flange has an inner side facing the web, an outer side facing away from the web, and two longitudinal edges;

characterized by

15.4) incorporating by a milling operation, subsequently to said hot-rolling step, a groove into the outer side of at least one of said two flanges, along at least one of said longitudinal edges,

15.5) said groove having a substantially V-shaped cross section with an opening width (b) lying within the range (0.5·e) <= b <= (1.5·e) and a depth (t) lying within the range 10 mm <= t <= (0.5·e), where (e) is the thickness of the flange in the direct vicinity of the groove.

IX. Cited evidence

In the statements setting out the grounds of appeal, and in the reply to them, the parties relied, among others, on the following documents which were filed in the opposition proceedings and are cited in the decision under appeal:

E1: WO 2005/038148 A1

E2: DE 10339957 B3

E3: DE 613 210 C

E5: US 2,018,625 A

E7: DE 10 2007 015 455 Al

E12: European Standard DIN EN 10248-2, "Warmgewalzte Spundbohlen aus unlegierten Stählen - Teil 2: Grenzabmaße und Formtoleranzen", 1995

E13: Extract from catalogue "Peiner Stahlspundwände - Peiner Stahlpfähle", PREUSSAG STAHL AG, with imprint "12.94", pages 7, 8 and 18

E17: Baer, O., "Stählerne Kastenspundbohlen: Untersuchungen über ihre technische und wirtschaftliche Eignung", TH Braunschweig, Peine, 1953

E18: DE 42 05 455 Cl

E19: DE 197 17 200 A1

E20: EP 0 790 093 Al

E21: WO 2007/137747 A1

E27: Extract from catalogue "Steel Sheet Piling - General catalogue - Edition 2003", ProfilARBED S.A., pages 46a and 47a

E28: Braun, H. et al., "Fachkunde Metall", Verlag Europa-Lehrmittel, 52nd edition, 1996, pages 166 to 171

In the statement setting out the grounds of appeal, appellant 1 submitted and referred to the following document for the first time:

E30: DE 659 442 C

In addition, appellant 1 reiterated its request made at the hearing before the opposition proceedings to hear Mr Ingolf Ehms as technical expert to provide evidence of the general knowledge of the skilled person.

X. The arguments of the parties, insofar as relevant for the present decision, can be summarised as follows:

(a) Consideration of E7, E19 to E21, E27, E28 and E30 in the proceedings

Appellants' case:

The opposition division decided not to admit any of documents E7, E19 to E21, E27 and E28 into the proceedings. However, these documents must be taken into consideration when assessing inventive step because they document common general knowledge in the relevant field of sheet piles, in particular the fact that milling is a well-known manufacturing process, the absence of any technical prejudice against milling, the fact that a V-shaped groove is easily milled, and the fact that so-called RZD, RZU and RH connection profiles were well-known in the art. E30 also documents that it is common general knowledge that, after hot-rolling sheet piles, the flash or excess metal can be trimmed off by milling.

(b) Request to hear Mr Ehms in the appeal proceedings

Appellant 1's case:

The opposition division decided not to admit any oral submission from Mr Ingo Ehms because appellant 1 had failed to indicate, in advance of the oral proceedings, Mr Ehms' professional function and qualification to speak. The appellant now submits that Mr Ehms is head of the department Patents & Licensing at Salzgitter Mannesmann Forschung GmbH, Duisburg. It is requested that he be heard as technical expert to provide evidence of common general knowledge in the relevant field of sheet piles.

Respondent's case:

The opposition division correctly decided not to admit any oral submission by Mr Ehms. In addition it is not comprehensible why he could not submit a written statement instead of making oral submissions.

(c) Main request - Novelty

Appellant 1's case:

The subject-matter of claim 1 is anticipated by the steel sheet pile disclosed in E1.

Respondent's case:

The appellants had expressly withdrawn the ground of lack of novelty during the oral proceedings before the opposition division, so that it constitutes a fresh ground of opposition in the appeal proceedings. Since the patent proprietor does not approve the discussion of this ground, it cannot be considered in the appeal proceedings, pursuant to G 10/91.

(d) Main request - Inventive step

Appellant 1's case:

The subject-matter of claim 1 is rendered obvious by the common general knowledge in the field of sheet piles. The skilled person, who starts from a steel sheet pile in double-T form with bare flanges and seeks to provide a flange end with means for coupling to a connection profile of the RZ type, as marketed by the respondent (see E27), knows two alternative solutions: either working a coupling groove into the flange end (see e.g. E1, E3, E13) or forming a wedge-shaped coupling bead on the flange end (see e.g. E1, E2, E18). He would choose the first alternative because it is less complicated and expensive. E3 teaches that it is common practice to mill coupling grooves in flange ends. E30 confirms that, following rolling of sheet piles, milling is standard operation, in particular to trim off the flash or excess metal. Moreover, it is common practice to weld the connection profile to the flange end, after it has been connected to it (E1, E18), and milled surfaces are known to be well suited for welding. In light of this, the skilled person would consider milling a coupling groove in the flange end, as required by feature (1.4). When doing so, he would inevitably mill a symmetric V-shaped groove, as shown in E1 (figure 4), as this would further reduce costs and effort while easing welding with the connection profile.

The width and depth of the V-shaped groove are dictated by the geometry of the profile RZ to be coupled to the groove. In particular, the profile RZD 16 (see E27, page 46a) has a clamp-shaped lock part with an inwardly curved strip which is suitable for overlapping the outer flank of the V-shaped groove of a sheet pile on a height of at least 4 mm, as required by European standard EN 10248 (see E12, table 15, form 4), and at most 15.6 mm, while the flange end of the sheet pile may not exceed a thickness (emax) of 36.19 mm. Hence, the maximum possible depth of the V-shaped groove is tmax= 15.6 mm, which lies between 10 mm and (1.5·emax), as required by feature (1.4.4). From figure 4 of E1 it is clear that, in the coupled condition, the inwardly curved strip of the profile RZD 16 makes an angle of approximately 45° with the outer side of the sheet pile flange. Therefore, the symmetric V-shaped groove is approximately an isosceles right triangle and b=2·t. Hence, the maximum possible width of the V-shaped groove is bmax= 31.2 mm, which is comprised between (1.5·emax) and (2·emax), as required by feature (1.4.3). These two dimensional requirements are still satisfied if some play is foreseen between the curved strip of the profile RZD 16 and the outer flank of the V-shaped groove, or if the angle for the curved strip (i.e. 45°) has a tolerance of ± 5°. Thus, given the geometry of the profile RZD 16 and the minimum locking overlap required by European standard EN 10248, the skilled person would inevitably arrive at features (1.4.3) and (1.4.4).

Alternatively, should the skilled person start from E3, he would also arrive at the subject-matter of claim 1 in an obvious manner. E3 discloses features (1) to (1.3.2) of claim 1. Contrary to the opposition division's view, figure 1 of E3 discloses also that the coupling means is formed by a V-shaped groove as required by features (1.4) to (1.4.2). The subject-matter of claim 1 thus differs from E3 only by the features that the groove is formed by milling (feature (1.4)) and that its width and depth meet the requirements of features (1.4.3) and (1.4.4). The step of milling the groove is rendered obvious by the teaching of E3 that it is known to hot-roll steel sheet piles in double-T form and subsequently mill coupling grooves in the flange ends (see page 1, lines 52 to 57 of E3). As shown above, the groove width and depth as defined in features (1.4.3) and (1.4.4) are dictated by the geometry of the connection profile RZ 16 which is to be coupled to the V-shaped groove.

As a further alternative, should the skilled person start from E1, the subject-matter of claim 1 would also lack an inventive step. As ruled by the opposition division, claim 1 differs from E1 only by the feature that the groove is formed by milling (feature (1.4)) and by feature (1.4.3). As explained above, the first distinguishing feature is a standard manufacturing option for the skilled person. In fact, E1 discloses that a coupling groove can be rolled or milled in the flange end of a sheet pile (page 2, line 10). In addition, the groove shown in figures 3 and 6 of E1 comprises sharp edges and the skilled person knows that such a groove can be formed only by machining, in particular by milling. Finally, as shown above, feature (1.4.3) is dictated by the geometry of the profile RZD 16.

The same arguments apply, mutatis mutandis, to the subject-matter of method claim 15.

Appellant 2's case:

The opposition division held that the subject-matter of claim 1 differs from E1 by the feature that the groove is formed by milling (feature (1.4)) and by the groove width defined by feature (1.4.3). However, feature (1.4.3) cannot distinguish the claimed sheet pile from that disclosed in E1, for the following reasons. It is stated on page 7, lines 6 and 7 of E1 that the thickness e* of the flange in the direct vicinity of the groove is 1.5 to 4.0 times, preferably 2 times, larger than the thickness e of the flange at the bottom of the groove. In figure 4 of E1, the groove flanks make an angle of approximately 45° with the flange surface and thus the groove is approximately an isosceles right triangle. When (1.5·e) <= e* <= (2·e), it is then inevitable that the groove width b is such that (2/3·e*) <= b <= (e*). This takes away the novelty of the range (0.5·e*) <= b <= (1.5·e*) defined in feature (1.4.3). Thus, claim 1 differs from E1 only in that the coupling groove is formed by milling.

This distinguishing feature is only one out of a limited number of obvious well-known alternatives, which the skilled person would apply to form the groove in the flange. In fact, it follows from the application as filed that the groove can be rolled or milled into the flange of the sheet pile and that, when the sheet pile is produced by hot-rolling, the machining steps of milling, planing and grinding are equally valid alternatives to form the groove in the completed sheet pile. This is confirmed by document E3 (page 1, lines 52 to 57): it describes sheet piles in double-T form having mutually engaging coupling grooves and projections in the flange ends, which are produced by milling or planing. E5 also suggests forming the coupling groove by machining the sheet pile (column 1, lines 11 to 16). Post-published document E7 proves that, before the priority date of the patent, there was the idea of milling the coupling groove and no prejudice existed against it.

In conclusion, the subject-matter of claim 1 lacks an inventive step.

The same arguments apply, mutatis mutandis, to the subject-matter of method claim 15.

Respondent's case:

Contrary to the appellants' view, E1 does not disclose a coupling means formed by a narrow V-shaped groove incorporated in the outer face of the flange by a milling operation, after hot-rolling of the double-T steel pile. Rather E1 only discloses a coupling means formed by a wedge-shaped bead 20 protruding from the outer face of the flange end 21. The wedge-shaped bead is produced when hot-rolling the sheet pile and is later trimmed to the desired height by using a cutting torch (figure 6 of E1). The grooves shown in figures 3 and 4 of E1 are by-products of the reinforcement of the central part of the flange with an extra material thickness 24; they do not constitute coupling grooves in the sense of the claim. E1 is silent as regards the groove width and it does not mention any specific value for the angle of the groove flanks. An angle of 45° cannot be scaled from the schematic drawings in figures 3 and 4 of E1 since no exact dimensions can be derived from such drawings. Thus, the sheet pile defined in claim 1 differs from that disclosed in E1 by all the features recited in the characterising portion of claim 1.

These distinguishing features are closely interrelated and have the effect that coupling means warranting a reliable coupling are provided in a easy, cost-efficient and precise manner. In particular, milling produces uniform coupling grooves along the whole length of the flange, with small dimensional and shape tolerances. Since the groove is V-shaped and relatively narrow, it is easy and simple to mill it into the hot-rolled sheet pile. Vice versa, the groove being a milled V-shaped groove, has small manufacturing tolerances and may be very narrow.

The technical problem to be solved can thus be formulated as how to produce improved coupling means in a simple, economic and precise manner.

The claimed solution is not rendered obvious by the cited prior art and common general knowledge.

E3 and E5 would not motivate the skilled person to mill a coupling groove into the flange end instead of hot-rolling a wedge-shaped bead on the flange end, as taught in E1. In fact, E3 teaches away from milling a coupling groove because it states that it is a complicated and very expensive operation to form interlocking grooves or protrusions in flange ends by milling (page 1, lines 52 to 57). E5 teaches only that "generally in the prior art, ... metallic pilings have been provided with complicated designs of interlocking terminal edges which, due to their design, either were formed by very difficult rolling operations or by machining" (column 1, lines 11 to 16 of E5).

Contrary to appellant 1's view, the claimed geometry of the coupling groove is not a direct consequence of the shape of the connection profile RZ, let alone that of the profile RZD 16. In fact, the profile RZ has originally been designed to be pushed over a flange end with its wedge-shaped bead, a positive connection being produced between the flange end and connection profile (see E1 figure 1; E27). It is neither disclosed nor suggested in the cited prior art that a positive connection be produced between the inwardly curved strip of the profile RZ and a narrow groove in the flange outer side, as in the claimed invention (see drawings).

Finally, as evidenced by post-published document E7, even if the groove of E1 were milled, it would not be necessarily be milled to a narrow V-shape as required in claim 1. In particular, in figure 1b of E7, the groove 16 is wide and its shape does not match that of the inwardly curved strip of the connection profile 18.

The claimed subject-matter thus involves an inventive step when starting from E1.

The same arguments apply if the skilled person were to start from E3, alternatively from a sheet pile with bare flanges, as argued by appellant 1. In particular, like E1, E3 discloses a coupling means formed by a wedge-shaped bead protruding from the outer face of the flange end (figure 1), and it fails to disclose a coupling means formed by a groove in the flange end.