A medicament inhaler (10) comprising: a mouthpiece (24) for inhalation by a patient； a delivery passage (34) for directing a flow (150) of air induced by inhalation through the nozzle； a channel (52) extending from the delivery passage； a reservoir (14) for containing a medicament, the reservoir having a dispensing port (44) connected to the channel； a cup (98) received in the channel and mobile between the dispensing slit and the delivery passage； a cup spring (104) requesting the cup towards one of the dispensing port and the passage； and a fork (68) movable between three positions and including a ratchet (106) adapted to engage the cup and prevent movement of the cup from the dispensing port (44) of the tank (14) to the passage (34) of delivery when the fork is in the first and second of the three positions, and allow said movement of the cup when the fork is in a third of the three positions, including the fork (68) in addition, a push bar (108) adapted to return the cup (98) from the delivery passage (34) to the dispensing port (44) after the movement of the fork (68) from the third to the first position； wherein the medicament inhaler further comprises at least one mobile cam (70) that includes three successive cam surfaces (90, 92, 94)； and a spring (69) requesting the fork against the cam such that the movement of the cam causes the fork to successively engage the cam surface and move the fork between the three fork positions.Un inhalador (10) de medicamento que comprende: una boquilla (24) para inhalación por un paciente； un pasadizo (34) de entrega para dirigir un flujo (150) de aire inducido por inhalación a traves de la boquilla； un canal (52) que se extiende desde el pasadizo de entrega； un depósito (14) para contener un medicamento, teniendo el depósito una lumbrera (44) de dispensación conectada al canal； una copa (98) recibida en el canal y móvil entre la rendija dispensadora y el pasadizo de entrega； un resorte (104) de copa que solicita la copa hac
