Cartridge interface assembly with driving plunger
A cartridge interface assembly including a driving plunger including an outer shaft, and a driver including an inner shaft, the inner shaft mating with an intermediate shaft, the intermediate shaft mating with the outer shaft, so that the shafts are movable telescopically with respect to one another, wherein rotation of the driver causes the driving plunger to advance in a direction away from the driver.
1. A combination cartridge and cartridge interface assembly comprising:
a rotationally immobile cartridge having an inner cylindrical surface, a first stopper slidingly inserted in the cartridge, a distal end and a substance therein for administration to a subject;
a cartridge interface assembly comprising:
a driving plunger comprising a first shaft; and
a driver comprising a second shaft, said second shaft mating with said first shaft, so that said shafts are movable telescopically with respect to one another, wherein rotation of said driver causes said driving plunger to linearly advance in a direction away from said driver, the arrangement being such that on insertion of the cartridge interface assembly in the rotationally immobile cartridge, the driving plunger is in complementary anti-rotation friction relation with the inner cylindrical surface, said complementary anti-rotation friction relation being the only force impeding rotation of the driving plunger with respect to the cartridge such that rotation of said driver causes said driving plunger to linearly advance only towards the distal end until the driving plunger abuts against the stopper whereupon the driving plunger urges the stopper towards the distal end for metering substance from the cartridge.
2. The combination according to claim 1 , wherein said driver comprises a gear wheel.
3. The combination according to claim 1 , wherein said second shaft is threadedly received inside a hollow portion of said first shaft.
4. The combination according to claim 1 , further including an intermediate shaft threadedly received inside a hollow portion of said first shaft, said second shaft being threadedly received inside a hollow portion of said intermediate shaft.
5. The combination according to claim 1 , wherein said driving plunger is at a distal end of said first shaft.
6. A method for interfacing between a driver and plunger slidingly disposed in a rotationally immobile cartridge, the method comprising:
providing a rotationally immobile cartridge having an inner cylindrical surface, a first stopper slidingly inserted in the cartridge, a distal end and a substance therein for administration to a subject
inserting a cartridge interface assembly in the rotationally immobile cartridge, said cartridge interface assembly comprising a driving plunger comprising a first shaft, and a driver comprising a second shaft, said second shaft mating with said first shaft, so that said shafts are moveable telescopically with respect to one another; and
rotating said driver to cause said driving plunger to linearly advance distally in said cartridge until abutting said plunger, the arrangement being such that on insertion of the cartridge interface assembly in the rotationally immobile cartridge, the driving plunger is in complementary anti-rotation friction relation with the inner cylindrical surface, said complementary sealing anti-rotation friction relation being the only force impeding rotation of the driving plunger with respect to the cartridge such that rotation of said driver causes said driving plunger to linearly advance only towards the distal end until the driving plunger abuts against the stopper whereupon the driving plunger urges the stopper towards the distal end for metering substance from the cartridge.