Multi-stroke delivery pumping mechanism for a drug delivery device for high pressure injections

1. A dual-chambered drug delivery device, comprising:

a cartridge having a first chamber for storing a medicament;

a second chamber in fluid communication with said first chamber;

a dose setting member for setting a medicament dose to be injected at an injection site;

a needle communicating with said second chamber for sequentially injecting portions of the medicament dose into the injection site;

a ratchet linearly movable between a first ratchet position and a second ratchet position by rotation of said dose setting member, said second ratchet position corresponding to the medicament dose being set; and

a rack movable by said ratchet when said ratchet is moved from said second ratchet position to said first ratchet position.

2. The dual-chambered drug delivery device according to claim 1 , wherein

upward movement of the dose setting member moves said ratchet upwardly from said first ratchet position to said second ratchet position.

3. The dual-chambered drug delivery device according to claim 1 , wherein

said rack has a movable rack member and a carriage, said movable rack member having a first rack position and a second rack position, said movable rack member moving said carriage when said movable rack member is moving toward said second rack position.

4. The dual-chambered drug delivery device according to claim 3 , wherein

said movable rack member moves up a ramp to move from said first rack position to said second rack position.

5. The dual-chambered drug delivery device according to claim 1 , wherein

said rack is connected to a cam wheel, such that movement of said rack rotates said cam wheel.

6. The dual-chambered drug delivery device according to claim 5 , wherein said cam wheel is connected to a piston such that rotation of said cam wheel reciprocatingly moves said piston, an upward stroke of said piston draws a portion of the medicament dose into said second chamber from said first chamber and a downward stroke of said piston expels the portion of the medicament dose.

7. A dual-chambered drug delivery device, comprising:

a cartridge having a first chamber for storing a medicament;

a second chamber in fluid communication with said first chamber;

a dose setting member for setting a medicament dose to be injected at an injection site;

a needle communicating with said second chamber for sequentially injecting portions of the medicament dose into the injection site;

a ratchet movable between a first ratchet position and a second ratchet position by rotation of said dose setting member, said second ratchet position corresponding to the medicament dose being set; and

a rack movable by said ratchet when said ratchet is moved from said second ratchet position to said first ratchet position; wherein

in said second ratchet position, said ratchet is accessible outside a remaining portion of said dual-chambered drug delivery device.

8. A dual-chambered drug delivery device, comprising:

a cartridge having a first chamber for storing a medicament;

a second chamber in fluid communication with said first chamber;

a dose setting member for setting a medicament dose to be injected at an injection site;

a needle communicating with said second chamber for sequentially infecting portions of the medicament dose into the injection site;

a ratchet movable between a first ratchet position and a second ratchet position by rotation of said dose setting member, said second ratchet position corresponding to the medicament dose being set; and

a rack movable by said ratchet when said ratchet is moved from said second ratchet position to said first ratchet position; wherein

said rack has a movable rack member and a carriage, said movable rack member having a first rack position and a second rack position, said movable rack member moving said carriage when said movable rack member is moving toward said second rack position; and

when said carriage engages teeth connected to said ratchet, further medicament doses are prevented from being set.

9. A dual-chambered drug delivery device, comprising:

a cartridge having a first chamber for storing a medicament;

a second chamber in fluid communication with said first chamber;

a dose setting member for setting a medicament dose to be injected at an injection site;

a needle communicating with said second chamber for sequentially injecting portions of the medicament dose into the injection site;

a ratchet movable between a first ratchet position and a second ratchet position by rotation of said dose setting member, said second ratchet position corresponding to the medicament dose being set; and

a rack movable by said ratchet when said ratchet is moved from said second ratchet position to said first ratchet position; wherein

said rack has a movable rack member and a carriage, said movable rack member having a first rack position and a second rack position, said movable rack member moving said carriage when said movable rack member is moving toward said second rack position; and

said cartridge is pressurized by a compression spring engaging a stopper disposed in said cartridge.

10. The dual-chambered drug delivery device according to claim 9 , wherein

a force from said compression spring moves said cartridge to pierce a septum of the cartridge.