T 456/10 – See The Big Picture

A reminder on how (not) to interpret drawings …

The patent proprietor filed an appeal against the decision of the Opposition Division (OD) to revoke the opposed patent.

Claim 1 as granted read:

Eccentric screw pump having an inner casing (2) made from wear-resistant and resilient material in a single-part or multi-part cylindrical housing casing (1); wherein an inner surface (3) of the casing (2) or the inner casing (2) is designed spirally with predetermined pitch direction and pitch length on its side (3) pointing inwards; having a helical or spiral rotor (6, 8) inserted with pretension in the casing in a first axial position (z1) and with radial eccentricity (9) and mounted (15, 16) on the drive side in this position and having the same pitch direction (7) as the stator (2); characterised in that an outlet opening (5) of the stator (2) is expanded starting from its end-face end on a piece of the axial conveying length radially outwards on its entire periphery so that an end-face edge (24), which rotates in pump operation, of the rotor end (23) placed close to the outlet opening - preferably for wear-related axial displacement (19; Δz) of the rotor - can be rotated in contact-free or released (G) manner with respect to the inner surface (3) of the stator.

The OD had found claim 1 as granted to lack novelty over document D0 and in particular over figure 1 of this document.

The Board disagreed:

*** Translation of the German original ***

[2.1.1] Document D0 concerns a stator for eccentric screw pumps the inner coating 2 of which can be readily and simply replaced […]. This result is obtained by means of a coating that is manufactured separately and which is used together with a casing (Mantel) that is divided lengthwise and the parts of which can be connected with each other in a non-permanent (lösbar) way […].

[2.1.2] Figure 1 shows a partial longitudinal section of the eccentric screw pump.

One can discern a gap on the left end-face, between the lower part of the rotor 4 and the coating 2 of the stator. Therefore, at the lower part of this end-face also, the rotor 4 is not in contact with the inner surface of the coating 2. However, one can see from figure 2 that the lower part of this end of the rotor 4 is in contact with the inner surface of the coating 2, i.e. that there is no gap.

[2.1.3] It clearly follows from page 1, lines 60-75 of the description that all figures show one and the same eccentric screw pump. Therefore, figure 2 is a front view of the stator according to figure 1 and should, therefore, show what the skilled person sees in figure 1 when looking at the pump from the left hand side. As figures 1 and 2 are intended to show the same eccentric screw pump but diverge in view of the above mentioned gap, the Board notes that the figures contradict each other in this respect.

[2.2] According to the established case law of the Boards of appeal, the technical disclosure of a document that forms part of the state of the art has to be considered as a whole (see T 56/87). The individual sections of a document must not be considered separately from the other parts but have to be seen in the overall context (see T 312/94).

[2.2.1] For this reason alone figure 1 cannot be used (gewürdigt) in isolation from the remainder of the document and in particular from figure 2.

[2.2.2] The fact that figures 1 and 2 show the same eccentric screw pump also hinders [the skilled person from using figure 1 in isolation] . In case the skilled person would try to find out which drawing is correct, he would not find any information in the description simply because the gap is not mentioned there. This is not surprising because the gap has nothing to do with the above mentioned purpose (see [2.1.1]).

[2.2.3] Therefore, the characterising feature of claim 1 – i.e. that a gap has to be provided on the left end-face, between the lower part of the rotor 4 and the stator 1,2, such that the lower part of the rotor 4 is not in contact with the inner surface of the coating 2 – does not follow unambiguously, for the skilled person, from the overall context of document D0 (see T 153/85 [headnote 3]).

[2.3] According to the established case law of the Boards of appeal, a document forming part of the state of the art is novelty destroying only if the subject-matter of the invention is disclosed in it directly and unambiguously (see e.g. T 511/92).

As the overall context of document D0 does not allow the skilled person to understand without doubt which of the two figures is correct, the distinguishing feature cannot be considered to be unambiguously disclosed.

Therefore, the subject-matter of claim 1 is novel within the meaning of A 54(1)(2) EPC 1973 over the disclosure of document D0.

Should you wish to download the whole decision (in German), just click here.

The file wrapper can be found here.