Automatic injection device with reset feature

• US 20020120235A1
• Filed: 01/02/2002
• Published: 08/29/2002
• Est. Priority Date: 01/05/2001
• Status: Active Grant

• Current Assignee: Novo Nordisk A/S
• Original Assignee: Novo Nordisk A/S
• Inventors: Enggaard, Christian
• Granted Patent: US 6,899,699 B2
• Time in Patent Office: Days
• US Class Current: 604/135
• CPC Class Codes: A61M 2005/202 cocking means, e.g. to bias the main drive spring of an injector
• CPC Class Codes: A61M 2005/2026 Semi-automatic, e.g. user activated piston is assisted by additional source of energy
• CPC Class Codes: A61M 2005/2407 from the rear
• CPC Class Codes: A61M 2005/2488 via rotation, e.g. threads or bayonet
• CPC Class Codes: A61M 2005/3126 Specific display means related to dosing
• CPC Class Codes: A61M 5/20 Automatic syringes, e.g. with automatically actuated piston rod, with automatic needle injection, filling automatically A61M5/142 , A61M5/46 take precedence; hypodermic projectiles F42B12/54
• CPC Class Codes: A61M 5/24 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 Class Codes: A61M 5/31501 Means for blocking or restricting the movement of the rod or piston A61M5/5013 takes precedence
• CPC Class Codes: A61M 5/31535 Means improving security or handling thereof, e.g. blocking means, means preventing insufficient dosing, means allowing correction of overset dose
• CPC Class Codes: A61M 5/31541 Means preventing setting of a dose beyond the amount remaining in the cartridge
• CPC Class Codes: A61M 5/3155 by rotational movement of dose setting member, e.g. during setting or filling of a syringe
• CPC Class Codes: A61M 5/31553 without axial movement of dose setting member
• CPC Class Codes: A61M 5/31583 based on rotational translation, i.e. movement of piston rod is caused by relative rotation between the user activated actuator and the piston rod
• CPC Class Codes: A61M 5/31593 Multi-dose, i.e. individually set dose repeatedly administered from the same medicament reservoir

Abstract

The present invention relates to a dose setting and expelling device comprising a drive member and a dose setting mechanism which simultaneously sets a given dose and stores the energy necessary for a subsequently driving the drive member in order to expel a dose of medicine from an injection device. According to the invention the dose setting mechanism allows adjustment in both directions, such that a given set dose can be reduced or cancelled by reversing the input motion, typically by rotating a setting member backwardly, this in contrast to the known devices which either requires an additional release mechanism or which cannot be reversed at all.

Claims

1. A dose setting device for use in combination with a fluid-filled reservoir, the dose setting device being adapted for repetitive injection of individually set doses of fluid from the reservoir, the dose setting device comprising:

a housing (10),

a drive member (30) adapted to expel a dose of medicine from the reservoir,

a spring means (70),

a dose setting assembly (40, 50, 60) mounted in the housing and connected to the spring means, the dose setting assembly comprising a dose setting member (50) being moveable in a first direction to a selected set position against the bias of the spring means, wherein movement of the dose setting member is accompanied by straining of the spring, and wherein the dose setting member is moveable in a second direction to selectively adjust the set dose,

a latch means (80, 90) associated with the housing to retain the apparatus in the set position against the bias of the spring means, and

the latch means being releasable to cause the drive member to expel the set dose from the syringe, the force for expelling the set dose being provided by the spring means.

2. A dose setting device as defined in claim 1, wherein the dose setting assembly further comprises a coupling member (60) in displaceable engagement with the dose setting member, the spring means acting on the coupling member, the coupling member acting on the dose setting member (50).

3. A dose setting device as defined in claim 2, wherein the dose setting member (50) and the coupling member (60) comprise mutually cooperating surfaces (54, 62) providing a coupling therebetween such that movement of the dose setting member in order to set a dose results in straining of the spring means.

4. A dose setting device as defined in claim 3, wherein one of the dose setting member (50) and the coupling member (60) is rotationally mounted on the drive member, the other being arranged in sliding, non-rotational engagement with the drive member.

5. A dose setting device as defined in claim 4, wherein the dose setting member (50) is rotationally mounted on a threaded portion of the drive member whereby 20 selectively setting a dose results in an axial movement of the dose setting member relative to the drive member, and the coupling member (60) is arranged in sliding, non-rotational engagement with the drive member, the spring means acting on the coupling member in a direction corresponding to the longitudinal axis of the drive member.

6. A dose setting device as defined in claim 5, wherein the threaded connection between the dose setting member and the drive member is of the non-locking type, and wherein the coupling (54, 62) between the dose setting member and the coupling member allows the dose setting member to be rotated in either direction, yet preventing the spring means to counter rotate the dose setting member.

7. A dose setting device as defined in any of claims 4-6, wherein the coupling (54, 62) is arranged between the cooperating surfaces of the dose setting member (50) and the coupling member (60), the coupling providing a resistance against rotation which is sufficiently to prevent the spring means to counter rotate the dose setting member, the resistance being easily overcome by a user rotating the dose setting member in either direction, whereby a user can selectively increase or decrease a dose setting.

8. A dose setting device as defined in any of claims 2-7, further comprising a threaded member (20) with a first internal thread, the drive member being a longitudinal drive member (30) having an external thread (31) corresponding to the first internal thread, the threads being non-locking having a pitch angle whereby axial movement of the drive member is obtained by an axial force applied to the drive member by the spring means.

9. A dose setting device as defined in claim 1, further comprising a threaded member (20) fixed in the housing and comprising a first internal thread, the drive member being a longitudinal piston drive member (30) having an external thread (31) corresponding to the first internal thread, the threads being non-locking having a pitch angle whereby axial movement of the piston drive member is obtained by an axial force applied to the piston drive member by the spring means.

10. A dose setting device as defined in claim 9, wherein the dose setting member (50) comprises a second internal thread (53), the dose setting member being rotationally mounted on the external thread (31) of the piston drive member, whereby selectively setting a dose results in an axial movement of the dose setting member relative to the piston drive member.

11. A dose setting device as defined in claim 10, wherein the dose setting assembly further comprises a coupling member (60) arranged in sliding, non-rotational engagement with the piston drive member, the spring means acting on the coupling member in a direction corresponding to the longitudinal axis of the drive member, the coupling member acting on the dose setting member (50).

12. A dose setting device as defined in claim 11, wherein the dose setting member (50) and the coupling member (60) comprise mutually cooperating surfaces (54, 62) providing a coupling therebetween such that rotation of the dose setting member in order to set a dose results in straining of the spring means as the coupling member is driven backwardly.

13. A dose setting device as defined in claim 12, wherein the threaded connection between the dose setting member and the piston drive member is of the non-locking type, and wherein the coupling (54, 62) between the dose setting member and the coupling member allows the dose setting member to be rotated in either direction, yet preventing the spring means to counter rotate the dose setting member.

14. A dose setting device as defined in claims 12 or 13, wherein the coupling (54, 62) is arranged between the cooperating surfaces of the dose setting member (50) and the coupling member (60), the coupling providing a resistance against rotation which is sufficiently to prevent the spring means to counter rotate the dose setting member, the resistance being easily overcome by a user rotating the dose setting member in either direction, whereby a user can selectively increase or decrease a dose setting.

15. A dose setting device as defined in any of claims 12-14, wherein the coupling between the dose setting member and the coupling member is provided by coupling parts having surfaces provided with sector shaped teeth (54, 62) having ramp shaped edges, the surfaces being forced against each other with the ramp shaped edges of the teeth on one surface abutting the ramp shaped edges of the teeth on the other surface, such that when the dose setting member is rotated in either direction, the teeth on the coupling parts will slide with their ramp shaped parts over each other, whereby the dosing member is axially displaced against the force of the spring and will jump back each time a top of the teeth is reached, the pitch of the toothing preferably being chosen so that a jump back takes place each time the dose setting is increased by a given dose unit.

16. A dose setting device as defined in any of claims 12-14, wherein the coupling is a frictional coupling provided between the cooperating surfaces, the necessary compression force between the surfaces being provided by the spring means acting on the coupling member.

17. A dose setting device as defined in claim 12 or 13, wherein the coupling can be selectively engaged and disengaged allowing the dose setting member to be rotated in either direction.

18. A dose setting device as defined in claim 17, wherein the coupling is an one-way ratchet mechanism comprising first and second ratchet members (125, 126) and which can be disengaged by relative axial movement between the first and second ratchet members.

19. A dose setting device as defined in any of the previous claims, wherein the latch means (80, 90) acts on the drive member.

23. An injection device for repetitive injection of individually set doses of a fluid from a reservoir, comprising:

a body adapted for receiving a cartridge containing a fluid to be injected, the cartridge defining the reservoir and containing a piston, and

a dose setting device as defined in any of the previous claims, the drive member acting on the piston in order to expel fluid from the cartridge.

24. An injection device for repetitive injection of individually set doses of a fluid from a reservoir, comprising:

a body comprising a reservoir containing a fluid to be injected, the reservoir containing a piston, and

a dose setting device as defined in any of the previous claims, the drive member acting on the piston in order to expel fluid from the reservoir.

20. A dose setting device for use in combination with a fluid-filled reservoir, the dose setting device being adapted for repetitive injection of individually set doses of fluid from the reservoir, the dose setting device comprising:

a housing (108),

a drive member (102) adapted to expel a dose of medicine from the reservoir in the syringe,

a spring means (106),

a dose setting assembly (101, 103) mounted in the housing and connected to the spring means, the dose setting assembly comprising a dose setting member (101) and a driving member (103) coupled to each other, the dose setting member being moveable in a first direction from an initial position to a selected set position against the bias of the spring means, wherein movement of the dose setting member is accompanied by straining of the spring means,

a first latch means (109) associated with the housing to retain the device in the set position against the bias of the spring means,

the first latch means being releasable to cause the drive member to expel the set dose from the syringe, the force for expelling the set dose being provided by the spring means, and

wherein the coupling is adapted to be selectively disengaged thereby allowing the dose setting member to be moved in a second direction to selectively adjust the set dose.

21. A dose setting device as defined in claim 20 comprising a second latch means (119) associated with the housing to retain the dose setting member in its coupled position,

the second latch means being releasable to allow the dose setting member to disengage from the driving means (103).

22. A dose setting device as defined in claim 20 or 21 wherein the spring means (106) is strained torsionally thus providing a rotating force on the dose setting member.

25. A method for infusing a flowable drug into a living subject is provided, comprising the steps of:

providing an injection device for repetitive injection of individually set doses of a drug from a reservoir, the injection device comprising a housing, a reservoir containing a drug to be injected and having an outlet means therefore, a drive member adapted to expel a dose of medicine from the reservoir, a spring means, a dose setting assembly mounted in the housing and connected to the spring means, the dose setting assembly comprising a dose setting member being moveable in a first direction to a selected set position against the bias of the spring means, wherein movement of the dose setting member is accompanied by straining of the spring, and wherein the dose setting member is moveable in a second direction to selectively adjust the set dose, a latch means associated with the housing to retain the injection device in the set position against the bias of the spring means, and the latch means being releasable to cause the drive member to expel the set dose from the reservoir, the force for expelling the set dose being provided by the spring means, the method comprising the further steps of;

establishing a flow connection between the outlet means and the subject,

selecting a dose by operating the dose setting member, and

releasing the latch means to cause the drive member to expel the set dose of drug from the reservoir.