Dose setting mechanism and medicament delivery device comprising ihe dose setting mechanism
A dose setting mechanism for a medicament delivery device, which dose setting mechanism comprises, a tubular member 10 having a longitudinal track 18 of a predetermined length; a dose drum 40 , coaxial with the tubular member 10 , and being axially and rotationally movable relative to the tubular member 10 ; a stop member 90 , axially movable but rotationally locked relative to the tubular member 10 , and further being in an axially slaved connection with the dose drum 40 ; wherein said stop member 90 comprises a track follower 98 in engagement with the longitudinal track 18 , such that rotational movement of the dose drum 40 relative to the tubular member 10 may cause a maximum axial displacement of said dose drum 40 and said stop member 90 , relative to the tubular member 10 , corresponding to said predetermined length.
1. A dose setting mechanism for a medicament delivery device, the dose setting mechanism comprising:
a tubular member defining an outermost housing comprising a dose window, where the tubular member has a longitudinal track positioned on an inside surface of the tubular member;
a dose drum that is positioned inside and coaxial with the tubular member and axially and rotationally movable relative to the tubular member, where the dose drum comprises a proximal end surface;
a threaded plunger rod positioned inside and coaxial with the dose drum; and
a stop member comprising a distal circumferential end surface that is axially movable relative to the tubular member and rotationally locked relative to the tubular member during dose delivery of a dose of medicament, wherein the distal circumferential end surface of the stop member abuts and has an axially slaved connection with the proximal end surface of the dose drum,
wherein the stop member comprises a track follower extending radially outward from an outer surface of the stop member and is slidably engaged with the longitudinal track on the inside surface of the outermost housing, and
wherein rotation of the proximal end surface of the dose drum engages the distal circumferential end surface of the stop member to cause a tactile and audible feedback signal during dose setting.
2. The dose setting mechanism of claim 1 , wherein the dose drum has a threaded connection with the tubular member.
3. The dose setting mechanism of claim 2 , wherein the track follower is a radial protrusion in engagement with the longitudinal track such that rotational movement of the dose drum causes a rotationally locked axial movement of the stop member relative to the tubular member.
4. The dose setting mechanism of claim 1 , wherein a length of the tubular member is defined by a distance between an initial position of the track follower relative to the longitudinal track and a distal end wall of the longitudinal track.
5. The dose setting mechanism of claim 4 , wherein the stop member is in the axially slaved connection between the initial position and the distal end wall.
6. The dose setting mechanism of claim 5 , wherein abutment of the track follower against the distal end wall prevents the dose drum from further axial displacement.
7. The dose setting mechanism of claim 1 , further comprising:
a dose drum follower and a dose blocker sleeve,
wherein the dose drum follower is axially and rotationally connected to the dose drum.
8. The dose setting mechanism of claim 7 , further comprising a blocking ring, wherein the dose blocker sleeve is in a second threaded connection with the threaded plunger rod.
9. The dose setting mechanism of claim 8 , wherein the blocking ring is fixedly connected to the threaded plunger rod.
10. The dose setting mechanism of claim 7 , wherein the dose blocker sleeve is axially movable relative to the dose drum follower and rotationally locked relative to the dose drum follower.
11. The dose setting mechanism of claim 7 , wherein the dose drum follower comprises radial holding elements configured to interact with a slanting ledge of the dose drum.
12. The dose setting mechanism of claim 11 , wherein the dose drum follower further comprises a proximal support ring configured such that the stop member is distally biased against a proximal end surface of the dose drum by the proximal support ring through interaction between the radial holding elements and the slanting ledge.
13. The dose setting mechanism of claim 12 , wherein the proximal end surface of the dose drum comprises a first undulating surface.
14. The dose setting mechanism of claim 13 , wherein the distal circumferential end surface of the stop member is a second undulating surface configured such that rotation of the dose drum relative to the stop member causes the tactile and audible feedback signal.
15. The dose setting mechanism of claim 11 , wherein the radial holding elements are arranged with slanting proximal and distal surfaces.
16. The dose setting mechanism of claim 7 , wherein the stop member is positioned radially outside an elongated half-tubular sleeve of the dose drum follower.
17. The dose setting mechanism of claim 16 , wherein the elongated half-tubular sleeve connects a proximal support ring with a distal forked sleeve of the dose drum follower.
18. The dose setting mechanism of claim 17 , wherein the distally forked sleeve comprises distally extending arms that comprise holding elements, and wherein the distally extending arms are resilient in a radial direction.
19. The dose setting mechanism of claim 7 , wherein a proximally directed force applied to the dose drum follower causes distal bias on the stop member by a support ring to be released.
20. The dose setting mechanism of claim 1 , wherein rotational movement of the dose drum relative to the tubular member causes a maximum axial displacement of the stop member, relative to the tubular member.