December 2025 Summary
Since the EPO’s Enlarged Board of Appeal issued decision G1/24, it has become clear from the number of recent decisions of EPO Technical Boards of Appeal that the description is not, in practice, being used to narrow the interpretation of otherwise clear claim language. (See our earlier article reporting T1999/23, T 1561/23, and T 2027/23)
In a further development, T1849/23 has become the first case where clear claim language is broadened by definitions and/or embodiments provided in the description.
Background
T 1849/23 concerned an appeal filed by Alois Kober GmbH, the Opponent, against the Opposition Division’s decision to maintain Lippert Components Inc.’s European patent EP 3166825. The patent relates to a trailer oscillation and stability control device that detects and controls the dangerous swaying of a trailer. Claim 1 as granted specified a device including an accelerometer and “an angular rate sensor (16) positioned and configured to measure rate of angular trailer deflection about a hitch pivot point (18)”.
The Opponent argued that claim 1, as granted, lacks novelty over the prior art as it discloses a yaw rate sensor on the trailer. In response, the Patentee asserted that the claimed features 1) “absolute yaw rate” and 2) “the rate of angular trailer deflection about the hitch pivot point” were distinct physical quantities. As such, the Patentee argued that the claim excluded a simple yaw rate sensor.
The Opposition Division sided with the Patentee and concluded that the prior art does not disclose this feature.
T 1849/23 – Appeal
During the appeal, the Board first conceded that the Patentee’s strict interpretation of the claim could be justified when the claim is read in isolation. However, the Board subsequently referred to G1/24 and proceeded to consult the description when interpreting the claims.
Upon consulting the description, the Board found that the only specific implementation of the sensor disclosed in the entire patent was a “gyroscope sensor”, i.e., a sensor for measuring the yaw rate. The description itself, in the preferred embodiments, described the sensor as a “raw angular rate sensor, i.e. a sensor measuring absolute yaw rate”.
As the description used the terms “angular rate sensor… about a hitch pivot point” and “gyro” (yaw rate sensor) interchangeably, the Board concluded that the claim could not be strictly construed as the Patentee submitted and decided that the claim must be construed in a broader manner.
As a result, this broader construction was found to encompass the yaw rate sensor disclosed in prior art and granted claim 1 was found to lack novelty.
Take Home Message
It is thus shown that a broader interpretation could be imported from the description into otherwise clear claim language, contrary to other recent appeal decisions that do not permit narrowing of otherwise clear claim language.
In view of T 1849/23, to avoid accidentally capturing unforeseen prior art, applicants should carefully consider whether to include broader definitions in the description and ensure the examples do not unintentionally broaden the claim language beyond the intended scope.
