US Patent 7668327 Hearing aid with a volume wheel

A hearing aid (1), fitted with an aperture (4) in a wall of a case (2, 3) receiving an adjustment wheel (5) which can be rotated from the outside by finger action around an axis of rotation (6) configured parallel to the wall (2), the adjustment wheel (5) driving a continuously adjustable electric volume control (7, 8), is characterized in that the adjustment wheel (5) rests in such manner at a shifting element (10) mounted in the case (2, 3) that a switch (13) shall be actuated when said wheel (5) is driven against a spring force (14) in the direction of shifting (17, 18, 19, 20).