Electrically actuated injector

• US 8,491,531 B2
• Filed: 05/08/2009
• Issued: 07/23/2013
• Est. Priority Date: 05/09/2008
• Status: Active Grant

• Current Assignee: Owen Mumford
• Original Assignee: Owen Mumford
• Inventors: Marshall, Jeremy, Rolfe, Steven Mark Guy
• Primary Examiner(s): BOUCHELLE, LAURA A
• Application Number:
  US12/991,308
• Publication Number:
  US 20110166521A1
• Time in Patent Office: 1,537 Days
• Field of Search: 604/134, 604/135, 604/157, 604/187, 604/232
• US Class Current: 604/135
• 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 2205/505 Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• 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 5/2053 Media being expelled from injector by pressurised fluid or vacuum for infusion A61M5/145, A61M5/155
• 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 5/31595 Pre-defined multi-dose administration by repeated overcoming of means blocking the free advancing movement of piston rod, e.g. by tearing or de-blocking

Abstract

An injector 12 includes a plunger 17 for expelling drugs from a cartridge 10 which can be inserted into the injector 12. An actuator 27 is provided for operating an escapement mechanism 21 to control the movement of the plunger under a drive force and hence the expelled drug.

Claims

1. An injector for use with a drug cartridge (10) comprising:

a plunger (17) for movement in a direction for acting, in use, to expel a dose or part thereof from the cartridge;

a power source (23a) for acting on the plunger to move it in the direction;

an escapement (21) for acting on the plunger to hold it, and release it against the action of the power source (23a) to control the movement of the plunger in the direction; and

a piezoelectric actuator (27) for moving the escapement between ‘

release’ and

‘

hold’

positions;

wherein the piezoelectric actuator (27) is in the form of a sheet or beam and bends in response to applied voltage, and further comprises a mechanical amplifier (28) interconnecting the actuator and the escapement.

2. The injector as claimed in claim 1, wherein the plunger (17) has a longitudinal ratchet (19, 20) and the escapement includes a toothed member (24) arranged for movement transverse to the direction to engage with and disengage from the ratchet.

3. The injector as claimed in claim 2, wherein the plunger (17) has a pair of opposed ratchet teeth surfaces (19, 20) and the toothed member comprises a collar with respective toothed portions (26, 25) for engaging respective ratchet surfaces (19, 20).

4. The injector as claimed in claim 3, wherein the respective toothed portions (26, 25) of the collar are 180°

out of phase with each other.

5. The injector as claimed in claim 3, wherein the teeth on the respective ratchet surfaces (19, 20) are offset ½

pitch side to side.

6. The injector as claimed in claim 1, wherein the mechanical amplifier is a pivoted lever (28).

7. The injector as claimed in claim 1 further including a cartridge (10) and wherein time taken between release and recapture of the ratchet by the escapement (21) is greater than minimum time for expelling a drug from the cartridge.

8. The injector as claimed in claim 1, wherein the power source (23a) is a spring or an hydraulic motor.

9. The injector as claimed in claim 8, wherein the spring is a constant force spring (24).

10. The injector as claimed in claim 1 further including a control (30) for controlling the application of voltage to the piezoelectric actuator.

11. The injector as claimed in claim 10, wherein the control (30) is arranged to control the rate of movement of the plunger in the direction.

12. The injector as claimed in claim 11 including a touch-sensitive interface/display (13) for allowing the setting of dosage volume.

13. The injector as claimed in claim 1 further including a trigger switch (14).

14. The injector as claimed in claim 1, wherein the plunger (17) has a longitudinal ratchet (19, 20) and the escapement includes a toothed member (24) arranged for movement transverse to the direction to engage with and disengage from the ratchet.

15. The injector for use with a cartridge (10) comprising

a plunger (17) co-operable with said cartridge to move in a direction to expel a dose or part thereof,

a power source for acting on the plunger to move it in the direction,

an electrically activated escapement operable to alternately hold and release the plunger against the action of the power source to allow incremental driven advance of the plunger;

and

a piezoelectric actuator (27) for moving the electrically activated escapement between ‘

release’ and

‘

hold’

positions;

wherein the piezoelectric actuator (27) is in the form of a sheet or beam and bends in response to applied voltage, and further comprises a mechanical amplifier (28) interconnecting the actuator and the escapement.