US 11,766,519 B2
Drug delivery mechanism
Sudeshna Dutta Ray, Thousand Oaks, CA (US); Scott R. Gibson, Granada Hills, CA (US); Daniel Eduardo Groszmann, Belmont, MA (US); Mehran Mojarrad, Thousand Oaks, CA (US); Robert Allen Dees, San Diego, CA (US); Jonathan Dean Johnson, San Marcos, CA (US); and Antonio S. Murcia, Oceanside, CA (US)
Assigned to AMGEN INC., Thousand Oaks, CA (US)
Appl. No. 16/961,762
Filed by AMGEN INC., Thousand Oaks, CA (US)
PCT Filed Jan. 17, 2019, PCT No. PCT/US2019/013905
§ 371(c)(1), (2) Date Jul. 13, 2020,
PCT Pub. No. WO2019/143753, PCT Pub. Date Jul. 25, 2019.
Claims priority of provisional application 62/618,288, filed on Jan. 17, 2018.
Prior Publication US 2021/0060259 A1, Mar. 4, 2021
Int. Cl. A61M 5/315 (2006.01); A61M 5/20 (2006.01)
CPC A61M 5/31511 (2013.01) [A61M 5/2033 (2013.01); A61M 5/31583 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A delivery assembly for a drug delivery device, the delivery assembly comprising:
a reservoir having a tubular housing extending along a longitudinal axis and having a delivery opening at a distal end;
a plunger disposed within the reservoir in engagement with the housing;
a flexible plunger rod comprising a spring having a predetermined preload amount and being operably coupled to the plunger; and
a feeding mechanism coupled to the flexible plunger rod and configured to drive the flexible plunger rod along the longitudinal axis of the housing to drive the plunger towards the distal end, the feeding mechanism including a drive gear assembly having a central opening for the spring to extend therethrough, the central opening including a thread configured to engage the spring such that rotation of the drive gear assembly relative to the spring causes the spring to move longitudinally through the drive gear assembly,
wherein the thread includes a shim that is configured to extend between adjacent coils of the spring.