Saturday, 19 February 2011

T 1225/08 – Drawing The Line

This decision deals with an appeal filed by the patent proprietor against the revocation of its patent by the Opposition Division (OD).

Claim 1 on file before the Board (which corresponds to claim 1 as granted) read:
A method of optically scanning a vehicle wheel, in particular a motor vehicle wheel, in which in a measuring step a wheel location is sensed by means of a light beam emitted by a light source and reflected to a position-sensitive receiver and the spacing of the sensed location relative to a reference location is measured from the directions of the emitted beam and the reflected beam, wherein for successive measuring steps the emitted beam and the position-sensitive receiver are pivoted synchronously about a common axis in a measuring plane which intersects the rim surface of the motor vehicle wheel at an obtuse or approximately right angle and which is below the horizontally arranged wheel axis, characterised in that the contours of the inward side, which is directed towards the wheel axis, of the wheel rim and of the radial wheel disc portion are ascertained from the measured spacings of adjoined wheel locations.

The decision contains an interesting paragraph on how to interpret a drawing of the closest prior art, document E4a, which is the international application published as WO 96/07880.

** Translated from the German **

[3] Document E4a discloses a method for balancing a wheel by means of balance weights, wherein the inner outline of the wheel rim is scanned and the scanned values are transmitted to a calculator. The calculator determines the inner outline of the wheel rim from the scanned values and then the optimized values and positions of the balance weights from the computed outline of the wheel rim […].

[3.3.1] Document E4a discloses several devices for determining the inner outline of the rim (Figures 1 to 4),

(Click to enlarge)
wherein the device disclosed in connection with Figure 3 is provided with a pivotally mounted distance meter.

In this embodiment the distance between the pivotally mounted distance meter and the respective point addressed at the outline of the rim is detected, and then the outline of the rim of the wheel is determined […].

Figure 3 shows a distance meter 6 mounted in a pivoting drive 9 and a dashed line 7 that extends from the distance meter to the wheel rim. According to the description of document E4, te distance meter depicted in Figure 3 may be “a mechanical, optical, ultrasonic or electrical (inductive or capacitive) distance meter.” […]

In its decision the OD endorsed the opinion of the [opponent] according to which
  • an optical distance meter necessarily contains a light source and a receiver, and
  • it follows from document E4a, and in particular its Figure 3, that the receiver consists in a position sensitive receiver and that the light beam emitted by the light source as well as the receiver are synchronously pivoted around a common axis.
However, Figure 3 is a merely schematic drawing of a pivotally mounted distance meter, which is to represent not only an optical but also, as explained above, a mechanical, ultrasonic or electrical (inductive or capacitive) distance meter. In such a simplified, undifferentiated and merely schematic representation, which is to comprise so different embodiments, the dashed line 7 extending from the distance meter to the wheel rim can also be understood to be a merely schematic representation of the distance or the connecting line between the distance meter and the respective point addressed at the outline of the rim, respectively. As a consequence, the skilled person implementing the optical embodiment mentioned in document E4a would understand the dashed line in Figure 3 to be merely the scanning direction of the optical distance meter, and would not take it as a hint that in such an implementation the dashed line is to represent a light beam that is emitted from a distance meter and that is reflected back to the distance meter by the rim.

It follows that document E4a does not disclose how the rotatable optical distance meter is to be equipped and which optical measurement principle is to be used. It also follows that the parts of the document E4a which deal with an optical implementation of the pivotally mounted distance meter do not teach the skilled person that the distance meter in such a configuration has to be a position sensitive receiver and that in addition to an optical receiver a light source that pivots in the same way as the receiver, or something of that kind.

In particular, the disclosure of document E4a does not exclude a pivotable optical receiver functioning with a stationary light source or without any scanning (antastend) emitted light beam (e.g. when a pivotable distance meter based on image acquisition is used).

Therefore, the Board is of the opinion that – in contrast to the understanding of the [opponent] and of the OD – document D4 does not directly and unambiguously disclose that the optical implementation of the pivotable distance meter comprises a position sensitive receiver functioning with a scanning (antastend) light source, and even less so that – as claimed – the emitter is pivoted together with the beam emitted by the light source synchronously about a common axis.

Therefore, all those features are novel over document E4a.

Finally, the Board maintained the patent as granted.

Should you wish to download the whole decision, just click here.

To have a look at the file wrapper, click here.