Patent ID: 8672898
Filing Date: 2014-03-18
Classification: A61M

Abstract:
1. A dose setting device for use in combination with an injection device comprising a fluid-filled reservoir and a drive member having an external thread that engages an axially fixed component within the device having an internal thread, wherein the drive member is adapted to expel a dose of fluid from the reservoir, the dose setting device being adapted for repetitive injection of individually set doses of fluid from the reservoir, the dose setting device comprising: a housing a spring mounted in the housing, wherein the spring acts to store a force for use in creating relative rotational motion between the drive member and the axially fixed component; a dose setting assembly mounted in the housing and connected to the spring, the dose setting assembly comprising a dose setting member being rotatable in a manner to set and adjust the size of a dose, the manner consisting of rotating the dose setting member in a first rotational direction to set the size of the dose and merely rotating the member in a second and opposite direction to reduce the size of the dose, when dose size reduction is necessary, wherein when the dose setting member is rotated in the second direction to reduce the size of a set dose, no drug is expelled from the device, wherein selectively reducing the size of the set dose consists solely of rotating the dose setting member in a second direction opposite that of the first direction a first direction and wherein rotating in the first direction is against the bias of the spring and results in the storage of energy in the spring for later use in expelling a drug from the reservoir, wherein during dose setting and adjusting the dose setting member does not move axially, a releaseable latch adapted to retain the dose setting member in the set position against the bias of the spring, wherein release of the latch causes the spring in the dose setting assembly to drive the drive member to thereby expel a set dose from a fluid-filled reservoir in the injection device when the dose-setting device is used in combination therewith, the force for expelling the set dose being provided by the spring, wherein release of the latch causes the spring to induce a relative rotational motion between the drive member and the axially fixed component having the internal thread thereby driving the drive member in a distal direction, and wherein numbers are printed along a helical line to form a scale on an external surface of a rotatable skirt so that only a portion of the numbers pass through a window in the housing during the setting of a dose, during dose size reduction without expulsion and during expulsion of a dose during injection from the fluid-filled reservoir, when the skirt rotates.