Injection Device

• US 20080312606A1
• Filed: 05/27/2005
• Published: 12/18/2008
• Est. Priority Date: 05/28/2004
• Status: Active Grant

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: Cilag Gmbh International (Johnson & Johnson)
• Inventors: Harrison, Nigel, Habeshaw, Rosemary
• Granted Patent: US 8,343,110 B2
• Time in Patent Office: Days
• US Class Current: 604/218
• 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 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence
• CPC Class Codes: A61M 5/3202 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 Class Codes: A61M 5/3204 Needle cap remover, i.e. devices to dislodge protection cover from needle or needle hub, e.g. deshielding devices
• CPC Class Codes: A61M 5/326 Fully automatic sleeve extension, i.e. in which triggering of the sleeve does not require a deliberate action by the user

Abstract

An injection device is described. A syringe 114 is received within a housing, the syringe having a bore terminating at a forward end in a hypodermic needle 118 and at a rearward end in a flared opening 210 in which a bung 134a having a bore 206 surrounded by a skirt 208 is inserted. A drive element 134 has a forward end consisting of a substantially flat annular region 200 that bears upon the skirt 208 of the bung 134a and surrounds a conical middle region 202 that is received in the bore 206 of the bung 134a. An actuator advances the drive element 134 so as to advance the bung 134a and discharge the contents of the syringe through the needle 118. The opening 210 in the rear of the glass syringe is flared by being provided with a radius. The combination of the radius at the opening 210 and the projecting conical middle region 202 of the drive element allows misalignments of the two to be managed during automated assembly. This is because the conical middle region 202 either pass straight into the opening 210 of the syringe, or contact the radius, which guides them towards the centre of the syringe bore. The radius and the substantially flat annular region 200 and the central conical portion 202 of the drive element 134 are so shaped and dimensioned that axial misalignment between the syringe 114 and the drive element 134 during assembly of the injection device are corrected by, firstly, the conical middle region 202 of the drive element 134 riding up the radius to a point at which, secondly, the substantially flat annular region 200 also makes contact with and rides up the radius, to align the drive element 134 in the bore of the syringe 114.

Claims

1. An injection device comprising:

a housing;

a syringe received within the housing, the syringe having a bore terminating at a forward end in a discharge nozzle and at a rearward end in a flared opening in which a discharge piston having a bore is inserted;

a drive element having a forward end consisting of a substantially flat edge region that is adapted to bear upon the discharge piston of the syringe and surrounds a projecting middle region that is adapted to be received in the bore of the discharge piston; and

an actuator for advancing the drive element so as to advance the discharge piston and discharge the contents of the syringe through the discharge nozzle.

2. An injection device according to claim 1 in which the flared opening in the syringe and the substantially flat edge and projecting middle regions of the forward end of the drive element are so shaped and dimensioned that axial misalignment between the syringe and the drive element during assembly of the injection device are corrected by, firstly, the projecting middle region of the forward end of the drive element riding up the flared opening of the syringe to a point at which, secondly, the substantially flat edge region of the forward end of the drive element rides up the flared opening of the syringe to align the drive element in the bore of the syringe.

3. An injection device according to claim 2 in which the line formed by the intersection of the flared opening of the syringe and a plane that passes through the axis of the syringe bore possesses a radius of curvature of between 33% and 100% of the radius of the syringe bore.

4. An injection device according to claim 2 in which the line formed by the intersection of the flared opening of the syringe and a plane that passes through the axis of the syringe bore possesses a radius of curvature of between 1 mm and 3 mm.

5. An injection device according to claim 3 in which the said radius of curvature is an average radius of curvature.

6. An injection device according to claim 3 in which the said radius of curvature is a minimum radius of curvature.

7. An injection device according to claim 3 in which the said radius of curvature is greater than the maximum radial extent of the substantially flat edge region of the forward end of the drive element.

8. An injection device according to claim 7 in which the said radius of curvature is at least 50% greater than the maximum radial extent of the substantially flat edge region of the forward end of the drive element.

9. An injection device according to claim 7 in which the said radius of curvature is at least 70% greater than the maximum radial extent of the substantially flat edge region of the forward end of the drive element.

10. An injection device according to claim 1 in which the flared opening of the syringe is substantially a surface of revolution about the axis of the syringe bore.

11. An injection device comprising:

a housing adapted to receive a syringe having a bore terminating at a forward end in a discharge nozzle and at a rearward end in a flared opening in which a discharge piston having a bore is inserted; and

a drive element that is adapted to bear upon the discharge piston of the syringe; and

an actuator for advancing the drive element so as to advance the discharge piston and discharge the contents of the syringe through the discharge nozzle, the forward end of the drive element consisting of a substantially flat edge region surrounding a projecting middle region.

12. An injection device according to claim 11 in which the forward end of the drive element has a cross-sectional area in the range 6.5 mm² to 110 mm².

13. An injection device according to claim 12 in which the forward end of the drive element has a cross-sectional area of 27.3 mm²±

8%.

14. An injection device according to claim 11 in which the forward end of the drive element is substantially circular in cross-section.

15. An injection device according to claim 14 in which the forward end of the drive element has a radius in the range 1.45 mm to 5.9 mm.

16. An injection device according to claim 15 in which the forward end of the drive element has a radius of 2.95 mm±

4%.

17. An injection device according to claim 11 in which the substantially flat edge region of the forward end of the drive element accounts for between 25% and 50% of the total area of the forward end of the drive element.

18. An injection device according to claim 17 in which the substantially flat edge region of the forward end of the drive element accounts for 37±

3% of the total area of the forward end of the drive element.

19. An injection device according to claim 11 in which the substantially flat edge region of the forward end of the drive element is substantially annular.

20. An injection device according to claim 19 in which the inner diameter of the substantially flat annular region is 61±

2% of the outer diameter.

21. An injection device according to claim 11 in which the projecting middle region of the forward end of the drive element is substantially circular in shape.

22. An injection device according to claim 11 in which the projecting middle region of the forward end of the drive element tapers from the substantially flat edge region to a neb.

23. An injection device according to claim 22 in which the projecting middle region of the forward end of the drive element tapers at an average angle of between 35±

10°

to the longitudinal axis of the drive element.

24. An injection device according to claim 22 in which the projecting middle region of the forward end of the drive element is substantially conical or frustoconical.

25. An injection device according to claim 24 in which the conical or frustoconical region of the forward end of the drive element has an included cone angle of 65±

5°

.