Autoinjector having needle shield triggering

Patent metadata

Field	Value
Publication number	US-2017143902-A1
Application number	US-201515318915-A
Country	US
Kind code	A1
Filing date	Jun 26, 2015
Priority date	Jun 27, 2014
Publication date	May 25, 2017
Grant date	—

Abstract

An autoinjector ( 100 ) for expelling a dose of a drug from a held cartridge ( 600 ) is described. A needle shield ( 350, 380 ) is axially movable relative to a base ( 200, 220 ) between an extended position and a collapsed position to operate a trigger lock ( 328, 388 ) configured for releasably maintaining a plunger ( 310, 400 ) in an initial axial position against the force of an actuator ( 330 ). One of the needle shield ( 350, 380 ) and the base ( 200, 220 ) defines one or more contact surfaces ( 382 ) each being resiliently slideable over a respective cooperating ramp surface ( 212 ) formed in the other of the needle shield ( 350, 380 ) and the base ( 200, 220 ) to provide a resistance to movement of the needle shield ( 350, 380 ) during needle shield displacement from the extended position towards the collapsed position. A high resistance to movement is obtained in a first stage of said needle shield displacement followed by a low resistance to movement in a second stage.

First claim

1 . An autoinjector for expelling a dose of a drug from a held cartridge, the autoinjector comprising:
a base, a needle that is fixedly mounted relative to the base a drug cartridge arranged relative to the base, the cartridge comprising:
an elongated body having a distal end and a proximal end and defining a central longitudinal axis, the body having a distally arranged outlet adapted for connection to the needle, and
a piston accommodated in the body, the piston configured for being driven axially in the distal direction to expel a dose of a drug through the outlet,
a plunger adapted for cooperation with the piston,
an actuator for providing a force and arranged to act on the plunger to drive the piston distally,
a needle shield axially movable relative to the base between an extended position and a collapsed position,

wherein the autoinjector defines a trigger lock configured for releasably maintaining the plunger in an initial axial position against the force of the actuator, the trigger lock being operated by the needle shield,
wherein one of the needle shield and the base defines one or more contact surfaces each being resiliently slideable over a respective cooperating ramp surface formed in the other of the needle shield and the base to provide a resistance to movement of the needle shield during needle shield displacement from the extended position towards the collapsed position, said one or more contact surfaces and the respective cooperating ramp surfaces creating a high resistance to movement in a first stage of said needle shield displacement followed by a low resistance to movement in a second stage of said needle shield displacement, and
wherein the trigger lock is configured for being operated for release of the plunger during said second stage of said needle shield displacement.

2 . An autoinjector as defined in claim 1 , wherein a needle shield spring acts to bias the needle shield towards the extended position.

3 . An autoinjector as defined in claim 1 , wherein a plunger thread component is associated with the plunger and the base defines a base thread component adapted for operatively coupling with the plunger thread component,
wherein prior to activation, the plunger thread component is operatively coupled with the base thread component and the trigger lock acts to prevent or limit relative rotation between the plunger thread component and the base thread component, thereby maintaining the plunger in the initial axial position, and
wherein the trigger lock is so configured that, as the needle shield is moved towards the collapsed position, the trigger lock is released enabling free relative rotation between the plunger thread component and the base thread component causing release of the plunger from the initial axial position and expelling the dose of the drug.

4 . An autoinjector as defined in claim 3 , wherein the trigger lock includes a first lock element that is axially movable as the needle shield moves from the extended position towards the collapsed position, wherein the first lock element and the plunger define respective cooperating lock geometries configured to, prior to activation, maintain a rotational retainment between the plunger thread component and the base thread component, the cooperating lock geometries being adapted to release said retainment to enable free rotation between the plunger thread component and the base thread component as the needle shield is moved towards the collapsed position.

5 . An autoinjector as defined as defined in claim 3 , wherein plunger is prevented from moving distally relative to the plunger thread component and wherein the plunger thread component is freely rotatable relative to the plunger.

6 . An autoinjector as defined in claim 3 , wherein the base thread component is fixedly disposed with respect to the base.

7 . An autoinjector as defined in claim 3 , wherein the base thread component is defined by a rotatable component that is axially fixed but rotatably mounted relative to the base, wherein the plunger thread component is prevented from rotating relative to the base, wherein the trigger lock includes a first lock element that is axially movable as the needle shield moves from the extended position towards the collapsed position, wherein the first lock element and the rotatable component define respective cooperating lock geometries configured to, prior to activation, maintain a rotational retainment between the rotatable component and the base, the cooperating lock geometries being adapted to unlock said retainment to enable free rotation between the rotatable component and the base as the needle shield is moved towards the collapsed position.

8 . An autoinjector as defined as in claim 7 , wherein the first lock element is prevented from rotating relative to the base and wherein the first lock element and the rotatable component define respective cooperating lock geometries configured to, prior to activation, maintain a rotational lock between the rotatable component and the first lock element, the cooperating lock geometries being adapted to unlock to enable rotation between the rotatable component and the first lock element as the needle shield is moved towards the collapsed position.

9 . An autoinjector as defined in claim 7 , wherein the plunger thread component is rotationally fixed relative to the plunger and the plunger is rotationally fixed relative to the base.

10 . An autoinjector as defined in claim 3 , wherein the plunger thread component is operatively coupled with the base thread component during an initial first axial displacement of the plunger and where the plunger thread component is released from being operatively coupled with the base thread component allowing the plunger to subsequently continue axial displacement in a second axial displacement.

11 . An autoinjector as defined in claim 3 , wherein an external diameter of the plunger thread component is larger than the internal diameter of a cylindrical section of the body of the cartridge.

Assignees

• Novo Nordisk As

Inventors

• Hansen Soeren Kjellerup
• Stefansen Mads Schenstroem

Classifications

• A61M5/3202

  Devices for protection of the needle before use, e.g. caps (A61M5/50 takes precedence; for infusion spikes A61M5/1626; protectors for sharps A61B50/3001) · CPC title

• A61M5/2033 Primary

  Spring-loaded one-shot injectors with or without automatic needle insertion (multishot dosing syringes A61M5/31525, needle insertion only A61M5/3287) · CPC title

• A61M2005/3267

  Biased sleeves where the needle is uncovered by insertion of the needle into a patient's body · CPC title

• A61M2005/2013

  triggering of discharging means by contact of injector with patient body · CPC title

• A61M5/50

  having means for preventing re-use, or for indicating if defective, used, tampered with or unsterile {(retractable needles or needle protectors with means for preventing re-use A61M5/321)} · CPC title