Drive assembly and medication delivery device

摘要

A drive assembly suitable for a medication delivery device comprises a housing, a drive member, a piston rod, a rotation sleeve, a guide member and a biasing member. The rotation sleeve is arranged to be displaced in a distal direction when the drive member is displaced in the distal direction by mechanical interaction of the drive member and the rotation sleeve with the rotation sleeve and the drive member both being guided axially by the at guide member. The biasing member exerts a force on the rotation sleeve acting in the proximal direction, said force being transformed into a rotational movement of the rotation sleeve. The rotational movement of the rotation sleeve being transformed into a rotational movement of the piston rod.

主权项

1. A drive assembly suitable for a medication delivery device, the drive assembly comprising:
a housing having a proximal end and a distal end, an axis running between the proximal end and the distal end; a drive member being axially displaceable with respect to the housing for delivering a dose of a medication; a piston rod which is rotatable with respect to the housing; a rotation sleeve which is rotatable and axially displaceable with respect to the housing; a guide member having at least one guide track extending axially, the rotation sleeve being arranged to releasably engage the at least one guide track; and a biasing member, wherein the rotation sleeve is arranged to be displaced in the distal direction when the drive member is displaced in the distal direction by mechanical interaction of the drive member and the rotation sleeve with the rotation sleeve and the drive member both being guided axially by the at least one guide track as long as the rotation sleeve engages the at least one guide track, and wherein the biasing member is biased during distal movement of the rotation sleeve, the biased biasing member exerts a force on the rotation sleeve acting in the proximal direction, said force being transformed into a rotational movement of the rotation sleeve with respect to the housing and a proximal movement of the rotation sleeve with respect to the drive member after the rotation sleeve has disengaged the at least one guide track, the rotational movement of the rotation sleeve being transformed into a rotational movement of the piston rod with respect to the housing.