Auto-pen for a two-chamber ampoule

• US 20060111666A1
• Filed: 09/01/2005
• Published: 05/25/2006
• Est. Priority Date: 09/02/2004
• Status: Active Grant

• Current Assignee: Ypsomed AG (Ypsomed Holding AG)
• Original Assignee: TecPharma Licensing AG (Ypsomed Holding AG)
• Inventors: Hommann, Edgar, Thompson, Ian, Scherer, Benjamin
• Granted Patent: US 7,815,598 B2
• Time in Patent Office: Days
• US Class Current: 604/89
• 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 5/2066 comprising means for injection of two or more media, e.g. by mixing
• CPC Class Codes: A61M 5/2448 comprising means for injection of two or more media, e.g. by mixing

Abstract

An injection device for use with a two-chamber ampoule, wherein the device includes a front casing part with which the two-chamber ampoule can be associated, a rear casing part, a threaded drive accommodated by the rear casing part, a piston rod which, during a blending movement, is moved by the threaded drive toward a dispensing end of the device and slaves at least a closing piston of the two-chamber ampoule in the process, wherein a spring element presses the piston rod toward the dispensing end during a delivery movement.

Claims

1. An injection device for use with a two-chamber ampoule, comprising:

a) a front casing part with which the two-chamber ampoule can be associated;

b) a rear casing part;

c) a threaded drive which is associated with the rear casing part; and

d) a piston rod which, during a blending movement, is moved by the threaded drive toward the dispensing end of the device and slaves at least a closing piston of the two-chamber ampoule, wherein a spring element presses the piston rod toward the dispensing end during a delivery movement.

2. The injection device according to claim 1, wherein the spring element is biased and the piston rod is released when at least one holding element is released.

3. The injection device according to claim 1, wherein the piston rod carries out an axial movement relative to the threaded nut during the delivery movement.

4. The injection device according to claim 3, wherein the piston rod is axially fixed relative to the threaded nut during the blending movement.

5. The injection device according to claim 2, wherein the at least one holding element engages with a hollow in the piston rod and is fixed relative to the piston rod during the blending movement.

6. The injection device according to claim 5, wherein the at least one holding element is pressed into the groove by the rear casing part during the blending movement, and in that the at least one holding means is thus moved relatively along the rear casing part.

7. The injection device according to claim 5, wherein the at least one holding element is pressed into a groove in the piston rod by a blocking element at a position of the piston rod which is reached at the end of the blending movement.

8. The injection device according to claim 7, wherein the blocking element protrudes through a window introduced in the rear casing part.

9. The injection device according to claim 7, wherein the blocking element is affixed to a triggering sleeve which at least partially encloses the rear casing part.

10. The injection device according to claim 7, wherein the at least one blocking element releases the at least one holding element by a translational or a rotational movement, such that each of them is pressed approximately radially outwards due to a force acting on the holding element.

11. The injection device according to claim 9, wherein during a delivery process, the at least one holding element is pressed into the window of the rear casing part, against the triggering sleeve slid over it.

12. The injection device according to claim 11, wherein an elastic element moves the triggering sleeve back to the position which the triggering sleeve had before the at least one holding element was released.

13. The injection device according to claim 11, wherein the front casing part and the rear casing part are detachably connected to each other.

14. The injection device according to claim 13, wherein the axial position of the at least one holding element relative to the threaded nut of the threaded drive is kept constant by a retainer.

15. The injection device according to claim 1, wherein the blending movement is transferred from the threaded drive onto the piston rod via a retainer.

16. The injection device according to claim 2, wherein the at least one holding element is at least one sphere.

17. The injection device according to claim 16, wherein a groove exhibits a depth corresponding at most to the radius of the at least one sphere, such that when an axial force is exerted on the piston rod, at least a force component acts radially outwards on the at least one sphere.

18. The injection device according to any one of claim 16, wherein a groove exhibits a width which is smaller than the diameter of the at least one sphere, such that when an axial force is exerted on the piston rod, at least a force component acts radially outwards on the at least one sphere.