IMPROVEMENTS IN AND RELATING TO A DOSING MECHANISM FOR A MEDICAMENT DELIVERY DEVICE

摘要

The present invention relates to a medicament delivery device such as an injector for self-administration of a medicament. There is a need to display the amount of the dialled dosage of medicament on the rotatable knob in figures sufficiently large and clear to be legible by those users having a degree of impaired vision. There is disclosed a dose dial mechanism for a medicament delivery device having a housing (4), the dose dial mechanism comprising a dose dial element (6) having a first thread (40) for engagement with the housing (4) and a dial sleeve member (8) having a second thread (48 ) for engagement with the housing (4) in which the dial sleeve member (8) is coupled to the dose dial element (6) so as to allow relative axial movement and inhibit relative rotational movement therebetween, and in which the pitc h of the second thread (48) is different from the pitch of the first thread (4 0) so as to cause a different axial displacement of the dial sleeve member duri ng axial displacement of the dose dial element.