Dose delivery mechanism

Patent metadata

Field	Value
Publication number	US-2023398309-A1
Application number	US-202217837959-A
Country	US
Kind code	A1
Filing date	Jun 10, 2022
Priority date	Jun 10, 2022
Publication date	Dec 14, 2023
Grant date	—

Abstract

A dose delivery mechanism includes a piston rod and a nut. The piston rod forms an outer thread meshing with an inner thread of the nut, and during dose setting, the nut is rotated relative to the piston rod to advance the nut with respect to the piston rod by a first distance into a distal direction, an actuation member that is movable by a user to effect delivery of a set dose, and a housing. A second threaded connection is configured to cause the actuation member to travel a second distance into the distal direction during dose setting. The actuation member is coupled via the nut to the piston rod during dose delivery to advance the piston rod by the first distance into a proximal direction upon proximal movement of the actuation member by the second distance, and the second distance is less than 1.5 times the first distance.

First claim

1 . A dose delivery mechanism comprising:
a piston rod; a nut, the piston rod forming an outer thread configured to mesh with an inner thread of the nut, during dose setting, the nut configured to be rotated relative to the piston rod to advance the nut with respect to the piston rod by a first distance into a distal direction; an actuation member movable by a user to effect delivery of a set dose; a housing; and a second threaded connection configured to cause the actuation member to travel a second distance into the distal direction during dose setting, the actuation member coupled via the nut to the piston rod during dose delivery to advance the piston rod by the first distance in a proximal direction upon proximal movement of the actuation member by the second distance, the second distance is-less than 1.5 times the first distance.

2 . The dose delivery mechanism according to claim 1 , wherein the first distance essentially equals the second distance.

3 . The dose delivery mechanism according to claim 1 , wherein a driver, a dose sleeve and a snap element are configured to rotate relative to the housing during dose delivery, and are connected to the housing via exactly one threaded connection.

4 . The dose delivery mechanism according to claim 1 , further comprising a dose setting unit with a dose sleeve indicating the set dose being rotationally coupled to the actuation member during dose setting, the actuation member and the dose sleeve are rotatable to set a desired dose.

5 . The dose delivery mechanism according to claim 4 , wherein the dose delivery mechanism further comprises a driver, the driver exerting a force onto the nut to drive the piston rod during dose delivery and
the dose sleeve and the driver form one piece or are rotationally and axially rigidly connected to each other.

6 . The dose delivery mechanism according to claim 1 , further comprising a spring configured to act between the housing and the actuation member during dose setting.

7 . The dose delivery mechanism according to claim 6 ,
wherein the spring is configured to support moving the actuation member by a user to effect delivery of the set dose.

8 . The dose delivery mechanism according to claim 6 , wherein the spring is a torsion spring,
or the spring is configured to be tensioned during dose setting.

9 . The dose delivery mechanism according to claim 6 , wherein the spring is coupled to a piston rod guide configured to guide linear movement of the piston rod and a driver,
or the spring is arranged in a proximal part of the dose delivery mechanism.

10 . The dose delivery mechanism according to claim 1 , wherein the actuation member is rotationally fixed to the nut during dose setting and dose delivery.

11 . The dose delivery mechanism according to claim 1 , wherein a driver and the housing form the second threaded connection.

12 . The dose delivery mechanism according to claim 1 , wherein the housing has a longitudinal through opening with an out of round inside circumference corresponding to an out of round outer circumference of the piston rod, or
a ball bearing or a gliding element made of low-friction material is provided to reduce friction during dose delivery.

13 . The dose delivery mechanism according to claim 1 , wherein a speed of the actuation member and a speed of the piston rod during dose delivery are a same.

14 . The dose delivery mechanism according to claim 1 , wherein the piston rod is configured to be linearly guided in the housing or the piston rod is non-rotatably mounted to the housing.

15 . A dose delivery mechanism according to claim 1 ,
wherein the nut is configured not to rotate relative to the housing or the piston rod during dose delivery.

16 . The dose delivery mechanism according to claim 1 , further comprising a dose setting unit with a dose sleeve indicating the set dose being rotationally coupled to the actuation member during dose setting, the actuation member and the dose sleeve are rotatable to set a desired dose, and the dose sleeve and the actuation member are rotationally decoupled during dose delivery, so that the actuation member does not rotate during dose delivery.

17 . The dose delivery mechanism according to claim 4 , wherein the dose delivery mechanism further comprises a driver, the driver exerting a force onto the nut to drive the piston rod during dose delivery, and
the dose sleeve and the driver form one piece or are rotationally and axially rigidly connected to each other and the driver directly abuts the nut to drive the piston rod during dose delivery or the driver is forced to rotate relative to the housing during dose delivery.

18 . The dose delivery mechanism according to claim 1 , further comprising a spring configured to act between the housing and the actuation member during dose setting the spring being disposed between the housing and a dose sleeve or between the housing and a driver.

19 . The dose delivery mechanism according to claim 6 , wherein the spring is coupled to a piston rod guide configured to guide linear movement of the piston rod and a driver,
or the spring is arranged in a proximal end section of the dose delivery mechanism.

20 . The dose delivery mechanism according to claim 1 , wherein a driver and an inner portion of the housing arranged radially inside of a dose sleeve form the second threaded connection.

Assignees

• Medmix Switzerland Ag

Inventors

• Bechtold Herbert
• Costello Peter Calvin
• Focht Kenneth Allen
• Smith Daniel P

Classifications

• A61M5/31585 Primary

  performed by axially moving actuator, e.g. an injection button · CPC title

• A61M5/31551 Primary

  including axial movement of dose setting member · CPC title

• A61M5/31541

  Means preventing setting of a dose beyond the amount remaining in the cartridge · CPC title

• A61M5/24

  Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or carpules, e.g. automatic {(ampoules or carpules A61J1/06)} · CPC title

• A61M5/31591

  Single dose, i.e. individually set dose administered only once from the same medicament reservoir, e.g. including single stroke limiting means · CPC title