Auto-injector apparatus

1. An auto-injector apparatus, comprising:

a flexible container containing a liquid medicament;

a needle communicated with the container;

a housing, the container being received in the housing;

a pump disposed in the housing and positioned to engage the flexible container and expel the medicament from the container through the needle upon relative movement between the pump and the container, wherein the pump contains a roller;

a main drive spring operably associated with the needle to extend the needle from a first needle position wherein the needle is completely received in the housing to a second needle position wherein the needle protrudes from the housing; and

a retraction spring operably associated with the needle to retract the needle back into the housing after the medicament is expelled from the container.

2. The apparatus of claim 1 , wherein: the main drive spring is operably associated with the pump to create the relative movement between the pump and the flexible container.

3. The apparatus of claim 1 , wherein: the housing further comprises a housing body having a housing interior and an opening, and a housing lid movably attached to the housing body, the lid being movable between a closed position closing the opening and an open position wherein the housing interior is accessible through the opening.

4. The apparatus of claim 3 , further comprising: a cocking linkage connecting the lid to the main drive spring and the retraction spring so that opening of the lid extends the main drive spring and the retraction spring.

5. The apparatus of claim 1 , further comprising: a container carriage reciprocally disposed in the housing, the container being received in the carriage so that the carriage, the container and the needle are movable together within the housing between first and second carriage positions corresponding to the first and second needle positions.

6. The apparatus of claim 5 , further comprising: a needle return chassis containing the needle; wherein the retraction spring of claim 1 is connected between the housing and the needle return chassis containing the needle; an interlock operably associated with the needle return chassis and the container carriage, the interlock releasing the needle return chassis after the pump expels the medicament from the container so that the retraction spring can withdraw the needle containing return chassis, the container carriage, the container and the needle to a safety position wherein the needle is fully received back in the housing.

7. The apparatus of claim 5 , wherein: the container carriage includes a roller track; and the roller is received in the roller track so that the roller is guided by the roller track as the roller rolls over the flexible container.

8. The apparatus of claim 7 , further comprising: a roller interlock between the roller and the container carriage to prevent the roller from rolling over the flexible container until after the main drive spring moves the needle to its second needle position.

9. The apparatus of claim 1 , wherein: the flexible container and the needle are connected together as part of a replaceable cartridge assembly replaceably received in the housing; and the pump and the main drive spring are connected to the housing for multiple use with sequential replaceable cartridge assemblies.

10. The apparatus of claim 1 , further comprising: a needle hub connected to the flexible container, the needle being attached to the needle hub and including a needle proximal end extending proximally from the needle hub; and a needle protection frame slidably connected to the needle hub, the needle hub being slidable relative to the frame from a first hub position wherein the frame extends proximally beyond the needle proximal end, to a second hub position wherein the needle proximal end extends proximally beyond the frame.

11. The apparatus of claim 10 , further comprising: a collapsible needle sheath supported by the frame and covering the needle to aid in maintaining sterility of the needle when the needle hub is in its first hub position relative to the frame.

12. The apparatus of claim 1 , wherein: the main drive spring comprises a coiled spring strip.

13. The apparatus of claim 1 , wherein: the housing comprises a closed single use housing having an interior inaccessible by a user without damage to the housing.

14. The apparatus of claim 13 , further comprising: the housing having a transparent window therein through which the flexible container is visible; and an opaque secondary container in which the housing is sealed.

15. The apparatus of claim 13 , further comprising: the housing having a transparent window therein through which the flexible container can be viewed; and a pull strip movable between a first position blocking the transparent window and a second position wherein the transparent window is unblocked so that the flexible container can be viewed prior to use.

16. The apparatus of claim 1 , wherein: the roller has a rotational axis, and the relative movement between the roller and the container is a relative longitudinal movement in a longitudinal direction transverse to the rotational axis, and the container is longitudinally fixed relative to the housing during at least part of the relative longitudinal movement between the roller and the container.

17. The apparatus of claim 1 , wherein: the roller includes two spaced co-axial roller portions; and the needle extends between the roller portions.