Auto injector with cartridge retention system

1. An auto injector for administering an injection of a medicament from a cartridge containing the medicament, the auto injector comprising:

a housing; and

a cartridge receiver with a cartridge receiver compartment configured to receive a cartridge assembly with at least one cartridge retention member when inserted through a cartridge receiver opening along a longitudinal axis; and

an ejector configured to support the cartridge assembly by being suspended to move along the longitudinal direction and being spring-loaded in the direction opposite of the receiving direction;

wherein the cartridge receiver compartment has a first section, at a first distance from the cartridge receiver opening, with inwardly extending first guide members that extend over first guide member angles and are spaced apart to form a passage at passage angles between the inward first guide members; wherein the inward first guide members form a first bore accepting the cartridge assembly when inserted through the cartridge receiver opening;

wherein one or more of the first guide members has a face that faces away from the cartridge receiver opening and forms a concave shape with a slope portion, at slope angles, leading towards a retention portion at or about a bottom portion of the concave shape;

wherein the cartridge receiver compartment has a second section with an annular shape, at a second distance from the cartridge receiver opening, and with second guide members with first faces that are inclined about a radial axis to the longitudinal axis and angularly arranged to extend at least partly over passage angles and first guide member angles;

wherein the second guide member has second faces that are inclined about a radial axis to the longitudinal axis and are arranged alternately with the first faces;

wherein the first faces and the second faces are inclined towards a greater distance from the cartridge receiver opening in a direction of rotation being either a clockwise or anticlockwise direction;

wherein the first faces and the second faces are separated by first riser portions; and

wherein the first riser portions are angularly positioned at or within the first guide member angles.

2. The auto injector according to claim 1 , wherein the first guide members have a first guide face that faces the cartridge receiver opening and forms a convex pointing shape with an apex directed towards the cartridge receiver opening.

3. The auto injector according to claim 1 , wherein the first section and the second section maintains a fixed angular position with respect to each other.

4. The auto injector according to claim 1 , wherein the first section and the second section are integrally formed with the cartridge receiver to form a single piece.

5. The auto injector according to claim 3 ,

wherein one or more first riser portions are angularly arranged at slope angles; and

wherein one or more first riser portions are angularly arranged between the retention angle and a centre of passage angles in a direction of rotation being either a clockwise or anticlockwise direction.

6. The auto injector according to claim 4 , wherein one or more of the first faces and the second faces are divided into sections separated by a second riser portion.

7. The auto injector according to claim 5 , wherein a first guiding member has an eject face that is inclined towards the cartridge receiver opening at angles beyond the retention angle in a direction of rotation being either a clockwise or anticlockwise direction.

8. The auto injector according to claim 1 , wherein the second guide members are configured as a first set of steps with treads that are inclined about the radial axis and a second set of steps with treads that are inclined about the radial axis;

wherein the treads of the first and second steps are inclined towards greater distance from the cartridge receiver opening for a clockwise or anticlockwise direction of rotation;

wherein the treads of the first set of steps are arranged more proximal to the cartridge receiver opening than the treads of the second set of steps; and

wherein the first set of steps are alternately arranged with the second set of steps; with riser portions between the steps, forming an annular member comprised by the second section.

9. The auto injector according to claim 3 , wherein the one or more first guide members and the second guide members are configured and angularly aligned such that:

upon insertion, the cartridge retention member passes the passage in a longitudinal direction, lands on a first section of the first face, by rotation follows the first face out over a second riser portion to a second section, and

upon ease of an insertion force, the cartridge retention member travels to the retention portion via the slope portion.

10. The auto injector according to claim 5 , wherein the one or more first guide members and the second guide members are configured and angularly aligned such that:

upon release, the cartridge retention member leaves the retention portion and lands on the first section of the second face, by rotation follows the second face out over a second riser portion to a second section; and

upon ease of a force, the cartridge retention member travels to the eject face, wherefrom a the cartridge retention member is guided towards the cartridge receiver opening via a passage.

11. The auto injector according to claim 1 , wherein the ejector comprises an ejector lock that is operative by one or more of rotation, translational movement or axial movement to move to a position where movement of the ejector is restricted in the direction of insertion.

12. The auto injector according to claim 1 , wherein the elongated ejector is configured with:

an ejector support face for supporting the cartridge or cartridge assembly, a longitudinal ejector slot extending towards the ejector support face from an ejector rest portion; and

an ejector lock supported for turning at least a fraction of a revolution and maintained in a fixed longitudinal position relative to the housing; wherein the ejector lock has a ejector lock support portion that is configured to align with and slide along the longitudinal ejector slot at a first angle and to be brought to align with the ejector rest portion at a second angle.

13. The auto injector according to claim 1 , wherein the ejector comprises an ejector rod configured with one or more ejector cut-outs to form one or more ejector cogs between the ejector cut-outs; and wherein the ejector lock is configured with one or more ejector lock cogs between one or more ejector lock cut-outs, respectively.

14. The auto injector according to claim 13 , wherein one or more of the cut-outs and the cogs have a substantially rectangular shape.

15. The auto injector according to claim 1 , comprising a plunger rod operative by movement along the longitudinal axis to exercise a pressing force on a cartridge accommodated in the cartridge assembly.

16. The auto injector according to claim 15 , wherein the plunger rod is accommodated in the ejector to be longitudinally displaceable.

17. The auto injector according to claim 15 , wherein the ejector lock comprises an ejector lock guide pin configured to engage with a plunger rod track provided in the plunger rod, such that longitudinal movement of the plunger rod, at least over a predefined range, inflicts a turning of the ejector lock about the longitudinal axis.

18. The auto injector according to claim 17 , wherein the plunger rod track comprises at least one track portion that guides the ejector lock guide pin from a first angle to a second to turn an ejector lock from the first angular position to the second angular position.

19. The auto injector according to claim 1 comprising an operational module configured to:

engage the plunger rod to move along the longitudinal axis to exercise a pressing force on a cartridge accommodated in the cartridge assembly; and

engage an ejector lock by one or more of rotation, translational movement or axial movement to move to a position where movement of the ejector is restricted in the direction of insertion.