VPG Systems UK Ltd v Air-Weigh Europe Ltd

For inventive-step analysis, the skilled person is identified by reference to the technical field and practical use of the invention. The court may define the inventive concept to streamline the Pozzoli SpA v BDMO SA analysis, but may instead compare the prior art with the claim as a whole. Commercial attractiveness is not part of the statutory obviousness inquiry, although technical attitudes and prejudices may be relevant. A patent claim directed to measuring vehicle loading through an inclinometer or accelerometer mounted on a single suspension component lacks inventive step where the prior art makes that adaptation obvious.

The claimant owned a patent for an on-board system indicating the loading state of a vehicle. The defendant admitted infringement if the patent were valid, but challenged claims 1 and 7 for lack of inventive step over three items of prior art. The principal prior art was Rothoff, which disclosed an accelerometer arranged in relation to a vehicle hub to detect loading-related angular displacement, but used the resulting signal to control vehicle suspension rather than to display the vehicle’s load.

The central issues were the construction of “suspension component”, whether claim 1 required a minimum level of accuracy, and whether the claimed adaptation of the prior art was obvious.

1. Construction. “Suspension component” was construed purposively. It included any component outside the chassis, body and drive train which was susceptible to angular variation relative to the vertical or horizontal when the vehicle was loaded and could therefore accommodate the claimed inclinometer or accelerometer. A non-rotating part of a hub assembly could fall within the term.
2. Accuracy. Claim 1 required the sensory output device to be suitable for indicating the vehicle’s loading state. The skilled person would therefore expect the system as a whole to possess sufficient sensitivity for that function, although the limitation was modest and did not exclude commercially unattractive systems.
3. Inventive-step framework. The structured approach in Pozzoli SpA v BDMO SA was applicable. The court identified the skilled person as a designer of on-board weighing systems working for a specialist supplier to the automotive industry. The inventive concept was the use of an inclinometer or accelerometer mounted on a single suspension component to generate a signal used to indicate the vehicle’s loading state.
4. Commercial prejudice or the commercial attractiveness of the proposed system was irrelevant to obviousness. Technical attitudes and prejudices within the skilled person’s field could be considered. The distinction reflected Hallen Co v Brabantia (UK) Ltd and the treatment of technical prejudice in Dyson Appliances Ltd v Hoover Ltd.
5. Rothoff disclosed an accelerometer detecting loading-related angular displacement, including through camber change, and permitted modification of its position and type. Its failure expressly to use the signal to inform a user of the vehicle’s load was the only material difference after construction. The skilled person would have considered it obvious to adapt Rothoff using the common general knowledge of load displays. The alleged weaknesses concerning camber, hub attachment, accuracy and the wording of Rothoff would not deter that adaptation.
6. The other cited prior art added little. Hi-Tech Scales supported the obvious use of an inclinometer, and the QG30 datasheet disclosed an obvious inclinometer to use. Claims 1 and 7 were therefore invalid for lack of inventive step over Rothoff.

First-instance decision. The judgment does not state any subsequent appellate history.