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    (Whirlpool Europe BV v BSH Bosch; Chancery Division; 19 September 2001)

    Whirlpool had patented a device for detecting an imbalance in loads in washing machines. The patent described the use of a tachogenerator to detect time varying changes in the speed of the washing machine drum prior to its spin cycle caused by the requirement for greater power to lift an unevenly distributed load fixed at a certain position by centrifugal force. Bosch successfully argued before the hearing officer that the prior art apparent from a Philips patent indicted that the Whirlpool was void for being obvious.

    The prior art indicated that, although the single embodiment in Philips related to the use of a tachogenerator to indicate imbalances in machine loads due to changing power requirements, the specification included its use for detecting time varying imbalances by ‘measurement of a characteristic of the drum’.

    The High Court agreed with the examiner in finding that the Whirlpool patent was invalid for obviousness. The prior art in the Philips’ patent ‘clearly encompassed’ use of a tachogenerator to detect time varying characteristics in a washing machine drum. According to the court, that answer would ‘stare in the face’, any person skilled in the art. Any manufacturer of washing machines would appreciate that a tachogenerator could be used to detect variations in the speed of the drum as an indicator of an imbalance. The hearing officer had, therefore, been right to revoke the patent.

    “Intellectual Property Newsletter” November 2001