Interpretative Spotlight: “surface protection”

The Opposition Division maintained the patent in amended form. Both the patent proprietor and the opponent filed an appeal.

Claim 1 of the main request was identical with claim 1 of the patent as granted and read:

1. Ball joint consisting of a joint housing (l), which is open at least on one side and has a housing recess (2), a joint pin (4), which is mounted in the housing recess (2) with its joint bal1 (3) provided with a surface protection and whose pin portion projects out of a housing opening (18), a bearing shell (5), which is disposed between the joint housing (1) and the joint bal1 (3), and a locking ring (7), which closes the housing recess (2) of the joint housing (1) and secures the bearing shell (5) disposed therein in the joint housing (1) and substantially follows the outer contour of the bearing shell(5) with its inner contour through a bevel or a formed radius, characterised in that the locking ring (7) to be inserted in the joint housing (1) is fixed in position in the joint housing (1) and comprises a sealing lip (17), lying against the joint bal1 (3) under an elastic preload, on the side of the housing opening (1 8) through which the pin portion of the joint pin (4) projects out of the joint housing (1).

Claim 1 of auxiliary request 1 had the additional feature that “the joint ball (3) has an extremely small (äußerst geringe) surface roughness as a consequence of the surface protection treatment.”

Claim 1 of auxiliary request 2 further specified that “the maximum surface roughness (Ry) of the joint ball is between 1 and 5 μm.”

** Translation from the German **

Main request

[3] The [patent proprietor] contests that the joint ball [of document E1] is provided with a surface protection […].

The wording of the claim “provided with a surface protection” does not further specify the nature of the surface protection and, therefore, has to be interpreted broadly. In its paragraph [0016] E1 discloses a lubricant which is applied to the joint ball. This necessarily reduces the friction between the joint ball and the bearing shell, which in its turn results in reduced wear. Therefore, the joint ball according to E1 can be said to be provided with a surface protection. […]

The auxiliary request was rejected for lack of clarity as the relative feature extremely small (äußerst gering) was found not to have any generally accepted technical meaning. The Board then deals with the second auxiliary request. Document E3 was found to be the closest prior art.

Auxiliary request 2

[6.5] The [patent proprietor] has submitted that the expression “provided with a surface protection” was to be interpreted as the subsequent application of a protective layer onto the joint ball and that processes which only resulted in a surface treatment, such as polishing or rolling were not covered by this expression. However, it was not able of indicating a passage in the opposed patent where the application of such a protective layer onto the joint ball was disclosed but derived this interpretation only from its own understanding of the verb “provide” (versehen).

As there is no explanation of what the expression “provided with a surface protection” means in the context of the invention and as neither the description nor one of the figures disclose a protective layer hat is applied to the joint ball, this expression cannot be limited to a protective layer but has to be interpreted broadly.

The skilled person knows that a reduced surface roughness results in a lower friction coefficient, which has a positive effect on the wear behaviour. When he/she wishes to obtain that the joint elements wear as little as possible, he/she would obviously consider to reduce the surface roughness of the joint ball as much as possible, e.g. by rolling, polishing or lapping. The thereby reduced wear results in protection for the surface. Therefore, a treatment of the joint ball which results in a reduction of the surface roughness has to be considered as a surface protection treatment within the meaning of the impugned patent which provides the joint ball with a surface protection.

The patent was revoked.

If you wish to read the whole decision (T 1313/08, in German), you download it here.