Injector apparatus having a clutch to inhibit forward movement of the plunger

• US 9,415,165 B2
• Filed: 10/15/2010
• Issued: 08/16/2016
• Est. Priority Date: 10/16/2009
• Status: Active Grant

• Current Assignee: Owen Mumford
• Original Assignee: Owen Mumford
• Inventors: Cowe, Toby
• Primary Examiner(s): Berdichevsky, Aarti B
• Assistant Examiner(s): Zhang, Jenna
• Application Number:
  US13/639,167
• Publication Number:
  US 20130046249A1
• Time in Patent Office: 2,132 Days
• Field of Search: 604/207, 604/208, 604/211, 604/134, 604/135
• US Class Current: 1/1
• CPC Class Codes: A61M 2005/202 cocking means, e.g. to bias the main drive spring of an injector
• CPC Class Codes: A61M 2005/2407 from the rear
• CPC Class Codes: A61M 2005/2492 via snap connection
• CPC Class Codes: A61M 2005/3103 Leak prevention means for distal end of syringes, i.e. syringe end for mounting a needle
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/583 by visual feedback
• 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 5/2033 Spring-loaded one-shot injectors with or without automatic needle insertion multishot dosing syringes A61M5/31525, needle insertion only A61M5/3287
• 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 5/3129 Syringe barrels A61M5/3205 and A61M5/50 take precedence
• CPC Class Codes: A61M 5/315 Pistons; Piston-rods; Guiding, blocking or restricting the movement of the rod or piston; Appliances on the rod for facilitating dosing ; Dosing mechanisms
• CPC Class Codes: A61M 5/31536 Blocking means to immobilize a selected dose, e.g. to administer equal doses
• CPC Class Codes: A61M 5/31548 Mechanically operated dose setting member
• CPC Class Codes: A61M 5/31551 including axial movement of dose setting member
• CPC Class Codes: A61M 5/31553 without axial movement of dose setting member
• CPC Class Codes: A61M 5/31556 Accuracy improving means
• CPC Class Codes: A61M 5/31558 using scaling up or down transmissions, e.g. gearbox
• CPC Class Codes: A61M 5/31561 using freely adjustable volume steps
• CPC Class Codes: A61M 5/31575 using scaling up or down transmissions, e.g. gearbox
• 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 5/31585 : performed by axially moving actuator, e.g. an injection button

Abstract

An injector apparatus includes a housing (10¹, 10²) for a cartridge or syringe, a plunger (40) for cooperating in use with the cartridge or syringe to express successive doses, a dose setting arrangement (16, 20) to select a dose volume, and a drive mechanism (22, 24) releasable to advance the plunger in respective predetermined increments of magnitude to express the successive doses. The drive mechanism includes a drive spring (22) for imparting movement directly or indirectly to the plunger (40), and the dose setting arrangement includes a dose setting element (16) moveable in a dose setting routine to define a magnitude of an increment of movement of the plunger for a given dose. The drive mechanism further includes a clutch arrangement (56) operable during the dose setting routine to inhibit forward movement of the plunger and/or to isolate the dose setting element from the force of the drive spring.

Claims

1. An injector apparatus for use with a cartridge (12) or syringe to deliver a plurality of doses therefrom, the injector apparatus comprising:

a housing (101, 102) configured to receive the cartridge or syringe;

a plunger (40) configured to cooperate, in use, with the cartridge or syringe to express successive doses;

a dose setting arrangement (16, 20) to select a dose volume; and

a drive mechanism (22, 24) releasable to advance said plunger in respective predetermined increments of magnitude to express said successive doses,

wherein said drive mechanism includes a drive spring (22) for imparting movement directly or indirectly to said plunger (40), and

said dose setting arrangement comprises a dose setting element (16) moveable in a dose setting routine to define a magnitude of an increment of movement of said plunger for a given dose,

said drive mechanism further including a clutch arrangement operable to selectively engage and disengage the drive spring (22) to/from the dose setting element (16),

wherein the dose setting element (16) is configured to be operably moveable between a first position and a second dose-setting position,

the dose setting element (16), in the first position, being engaged to the drive spring (22) to rotate under the influence of the drive spring (22), and

a movement of the dose setting element to the second dose-setting position moves the clutch arrangement into engagement with the drive mechanism and disengages the dose setting element (16) from the drive spring (22) so that, when the dose setting element (16) is in the second dose-setting position, the clutch arrangement bears a load exerted by the drive spring (22) and said dose setting element (16) is freed from the load of the drive spring (22) such that a dose-setting movement of the dose setting element (16) in said second dose-setting position for said dose setting routine is not influenced by the drive spring (22).

2. The injector apparatus according to claim 1, wherein said dose setting element (16) is moveable angularly, and an angular position of the dose setting element (16) relative to the housing defines said increment of plunger movement.

3. The injector apparatus according to claim 2, wherein said clutch arrangement includes a clutch element (56) moveable between a disengaged position and an engaged position.

4. The injector apparatus according to claim 3, wherein said clutch element (56) is arranged within the housing to move axially with said dose setting element (16), and axial movement of said dose setting element from the first position to the second dose-setting position causes said clutch element (56) to inhibit forward movement of the plunger.

5. The injector apparatus according to claim 4, wherein said dose-setting element (16) and said housing (101, 102) include complementary abutments (62, 64) that, in a first mode, engage to prevent relative rotation of said dose setting element (16) relative to said housing when said dose setting element (16) is in said first position and, in a second mode, disengage to allow relative rotation of the dose setting element (16) relative to the housing when said dose setting element is in said second dose-setting position.

6. The injector apparatus according to claim 5, wherein upon moving said dose setting element (16) from said first position to said second dose-setting position, said clutch element (56) engages before disengagement of the complementary abutments (62, 64) on said dose setting element and said housing.

7. The injector apparatus according to claim 4, wherein returning said dose setting element (16) from said second dose-setting position to said first position, after having set a predetermined dose via a rotation of the dose setting element (16) relative to the housing while in said second dose-setting position, disengages the clutch element (56) and thereby releases the drive mechanism (22, 24) to cause said plunger (40) to advance by a predetermined increment corresponding to said predetermined dose.

8. The injector apparatus according to claim 3, wherein an operative movement of said clutch element (56) to said disengaged position moves said plunger against the load of the drive spring (22) to relieve a residual load between said plunger and said cartridge or syringe.

9. The injector apparatus according to claim 1, wherein said plunger (40) is threadedly engaged with an associated control element (24), whereby linear movement of said plunger is accompanied by rotation of one of the plunger and the control element, and a magnitude of the increment of movement is controlled by limiting said rotation.

10. The injector apparatus according to claim 9, wherein a stop surface (54), associated with said dose setting element (16), is adjustable on movement of said dose setting element to define an angular increment of movement for relative rotation between the plunger (40) and the control element (24) upon release of said drive mechanism.

11. The injector apparatus according to claim 10,

wherein an intermediate shuttle member (20) is threadedly engaged with said dose setting element (16) and is constrained to rotate with the rotatable one of the plunger (40) and the control element (24), and

wherein an extent of relative angular movement of the shuttle member (20) and the dose setting element is set by a relative position of the stop surface associated with the dose setting element.

12. The injector apparatus according to claim 1, wherein said drive spring (22) is a torsion spring.

13. The injector apparatus according to claim 1, wherein said drive spring (22) is a compression spring.

14. An injector apparatus for use with a cartridge (12) or syringe to deliver a plurality of doses therefrom, the injector apparatus comprising:

a housing (101, 102) configured to receive the cartridge or syringe;

a plunger (40) configured to cooperate, in use, with the cartridge or syringe to express successive doses;

a dose setting element (16) movable in a dose setting routine to select a dose volume; and

a drive mechanism (22) releasable to advance said plunger in respective predetermined increments of magnitude to express said selected dose volume,

said drive mechanism (22) including a drive spring (22) for providing motive force directly or indirectly to said plunger to advance said plunger, and

said drive mechanism further including a clutch arrangement, the clutch arrangement being movable between

a first position, in which a clutch element (56) of the clutch arrangement, operable between the housing and a drive shaft of the drive mechanism (22), frees the drive shaft to rotate relative to the housing, and the motive force of the drive spring (22) is transmitted to the dose setting element (16) and the drive shaft to urge the dose setting element (16) and the drive shaft to rotate, and

a second position, corresponding to said dose setting routine, in which the clutch element (56) of the clutch arrangement engages the drive shaft to the housing, such that the motive force of the drive spring (24) is transmitted via the clutch element (56) to the housing (10) and the dose setting element is free to rotate independently of the drive shaft and is free of influence by the motive force of the drive spring (22).

15. The injector apparatus according to claim 14, wherein the clutch arrangement is operable, in the second position, to inhibit forward movement of the plunger.

16. The injector apparatus according to claim 14, wherein a rotation of the dose setting element (16), when the clutch arrangement is in the second position, selects the dose volume expressed upon release of the drive mechanism.

17. The injector apparatus according to claim 14, wherein the dose setting element (16) is movable between a dose setting position and a rest position,

a movement of the dose setting element (16) from the rest position to the dose setting position causing the clutch arrangement to move to the second position, the dose setting element (16) being rotatable free of influence from the motive force of the drive spring (22) when in the dose setting position.