Power pack assembly
A power pack assembly for a medicament delivery device is presented having a housing extending along a longitudinal axis and having a proximal and a distal end, a container carrier unit arranged longitudinally and bi-directionally movable in relation to the housing, a plunger pusher releasably connected to the container carrier unit, and an actuator unit connected to the plunger pusher, wherein the actuator unit is configured to drive the plunger pusher in a sequence in which the plunger pusher and the container unit are moved together distally relative to the housing until a virtual distal stop is met. Proximal movement of the plunger pusher causes the container carrier unit to interact with a proximal stop element of the housing whereby the plunger pusher is released from the container carrier unit and the plunger pusher continues to move proximally a further distance.
1 . A power pack assembly for a medicament delivery device comprising:
a housing base extending along a longitudinal axis (L) and having a proximal end near a dose delivery site and a distal end opposite the proximal end;
a container carrier unit arranged longitudinally and bi-directionally movable in relation to the housing base;
a plunger pusher releasably connected to the container carrier unit;
a resilient member arranged on the proximal end between the housing base and the container carrier unit, the resilient member being configured to exert a pulling force on the container carrier unit towards the proximal end; and
an actuator unit connected to the plunger pusher,
wherein the actuator unit is configured to drive the plunger pusher in a sequence in which the plunger pusher and the container carrier unit move together distally in relation to the housing base followed by a proximal movement, provided by the resilient member, until the container carrier unit interacts with a proximal stop element of the housing base whereby the plunger pusher is released from the container carrier unit, and the plunger pusher continues to move proximally a further predetermined distance.
2 . The power pack assembly according to claim 1 , wherein the plunger pusher is releasably connected to the container carrier unit by a coupling element, and wherein the coupling element is fixedly or integrally connected to the container carrier unit.
3 . The power pack assembly according to claim 2 , wherein the coupling element comprises a flexible member.
4 . The power pack assembly according to claim 3 , wherein the housing base comprises a track which is configured to force the flexible member to be in contact with the plunger pusher until the container carrier unit interacts with the proximal stop element of the housing base such that the flexible member is allowed to flex and thereby release the plunger pusher from the container carrier unit.
5 . The power pack assembly according to claim 3 , wherein the flexible member comprises a ledge which contacts with the plunger pusher.
6 . The power pack assembly according to claim 1 , wherein the actuator unit is configured to regulate the exerted force of the resilient member on the container carrier unit.
7 . The power pack assembly according to claim 1 , wherein the actuator unit comprises a driving force element and a lead screw, wherein a first end of the lead screw is connected to the driving force element through a gearbox, and wherein a second end of the lead screw is connected to the plunger pusher.
8 . The power pack assembly according to claim 7 , wherein the driving force element is a motor.
9 . The power pack assembly according to claim 8 , wherein the power pack assembly further comprises an electronics set, which comprises a controller configured to control the motor.
10 . The power pack assembly according to claim 9 , wherein drive the plunger pusher and the container carrier unit are together distally moved in relation to the housing base until a distal stop is met, and wherein the distal stop is a programmable stop condition in the controller such that the distal movement of the plunger pusher and the container carrier unit is stopped when the stop condition has occurred.
11 . The power pack assembly according to claim 1 , wherein the plunger pusher further comprises a rod element.
12 . The power pack assembly according to claim 1 , wherein the medicament delivery device further comprises a secondary sensor configured to detect an event of the medicament delivery device, and wherein the event is the stop condition of the controller.
13 . The power pack assembly according to claim 1 , wherein the resilient member may comprise of a band spring, constant force spring, ribbon, or resilient wire.
14 . A power pack assembly for a medicament delivery device comprising:
a housing extending along a longitudinal axis (L) and having a proximal end near a dose delivery site, a distal end opposite the proximal end, and a track;
a container carrier unit arranged longitudinally and bi-directionally movable relative to the housing;
a plunger pusher comprising a transition portion, where the plunger pusher is releasably connected to the container carrier unit;
a resilient member arranged on the proximal end between the housing and the container carrier unit, the resilient member being configured to exert a pulling force on the container carrier unit towards the proximal end; and
an actuator unit operatively connected to the transition portion,
wherein the actuator unit moves the plunger pusher axially such that the container carrier unit moves axially distally relative to the housing followed by proximal movement, provided by the resilient member, of the plunger pusher and the container carrier unit until the container carrier unit contacts a proximal stop on the housing whereby the plunger pusher disengages from the container carrier unit and continues to move proximally a further predetermined distance.
15 . The power pack assembly of claim 14 , wherein the actuator unit comprises a lead rod operatively engaged with the transition portion.
16 . The power pack assembly of claim 15 , wherein the lead rod comprises screw threads and rotates relative to the plunger pusher and is axially fixed to the housing.
17 . The power pack assembly of claim 15 , wherein a releasable connection between the container carrier unit and the plunger pusher is a coupling element comprising a flexible member.
18 . The power pack assembly of claim 15 , wherein the lead rod is moved by a motor axially fixed relative to the housing.
19 . The power pack assembly of claim 15 , wherein the plunger pusher further comprises a pushing portion that engages with and axially moves a plunger rod relative to a medicament container positioned in the container carrier unit when the lead rod is rotated and the plunger pusher disengages from the container carrier unit.
20 . The power pack assembly of claim 14 , wherein the actuator unit is configured to regulate the exerted force of the resilient member on the container carrier unit.