Automatic pharmaceutical dispensing syringe

A pharmaceutical dispensing syringe, for use with a needle assembly and a cartridge of the type having a cartridge barrel, an open end, a needle end to which the needle assembly is mountable, a piston within the barrel and a flowable pharmaceutical within the barrel between the piston and the needle end, the needle assembly having a tip, the syringe comprising:

• a main barrel having a proximal end, a distal end and a hollow interior sized to house the cartridge therein, the tip of the needle assembly extending past the distal end;
• a user manipulatable cap rotationally mounted to the proximal end of the barrel;
• a dosing screw, including dosing screw threads, housed within the main barrel and rotationally driven by the cap, the dosing screw being coupled to the cap to permit relative axial movement therebetween;
• a piston driver threadably coupled to the dosing screw threads and having a distal driver end continuously engaging the piston;
• means for biasing the piston driver towards the piston;
• and
• means for preventing the piston driver from rotating within the main barrel so that rotary motion of the cap causes rotary motion of the dosing screw which causes relative axial motion between the dosing screw and the piston driver.

A pharmaceutical dispensing syringe, for use with a needle assembly and a cartridge of the type having a cartridge barrel, an open end, a needle end to which the needle assembly is mountable, a piston within the barrel and a flowable pharmaceutical within the barrel between the piston and the needle end, the needle assembly having a tip, the syringe comprising:

• a main barrel having a proximal end, a distal end and a hollow interior sized to house the cartridge therein, the tip of the needle assembly extending past the distal end;
• a user manipulatable cap rotationally mounted to the proximal end of the barrel;
• a dosing screw, including dosing screw threads, housed within the main barrel and rotationally driven by the cap, the dosing screw being coupled to the cap to permit relative axial movement therebetween;
• a piston driver threadably coupled to the dosing screw threads and having a distal driver end engaging the piston;
• means for biasing the piston driver towards the piston;
• means for preventing the piston driver from rotating within the main barrel so that rotary motion of the cap causes rotary motion of the dosing screw which causes relative axial motion between the dosing screw and the piston driver;
• an outer sleeve slidably mounted over the main barrel movable between a safe position, at which the outer sleeve covers the tip of the needle assembly, and a use position, at which the tip of the needle is exposed;
• a brake pad housed with a window formed between the main barrel and the outer sleeve for movement between a brake applied position, at which the brake pad frictionally secures the piston driver to the main barrel, and a brake released position, at which the brake pad substantially releases the piston driver from the main barrel;
• and
• a brake actuator element which keeps the brake pad in the brake applied position until the outer sleeve is at the use position.

A method for automatically dispensing a desired dose of liquid pharmaceutical from a cartridge, of the type having a body with an open end, a needle end, a piston within the body and a flowable pharmaceutical within the body between the piston and the needle end, through the needle of a needle assembly fluidly coupled to the body, the method comprising the steps of:

• providing a main barrel having a proximal end, a distal end and a hollow interior sized to house the cartridge therein;
• sliding an outer sleeve slidably mounted over the barrel from a use position, with the needle being exposed, to a safe position, with the outer sleeve enclosing the needle, to compress an injection spring captured between the outer sleeve and the main barrel;
• securing the injection spring when the outer sleeve is in the safe position;
• securing a piston driver to the main barrel to prevent relative axial movement therebetween;
• placing a distal end of the outer sleeve against a patient;
• rotating a cap mounted to the proximal end of the barrel to compress a dosing spring;
• releasing the injection spring;
• driving the main barrel, cartridge and needle assembly in a distal direction so to inject the needle into a patient;
• releasing the piston driver after the needle is injected into the patient;
• and
• driving the piston driver against the piston to force the desired dose of pharmaceutical within the cartridge through the needle and into the patient.

A pharmaceutical dispensing syringe, for use with a needle assembly and a cartridge of the type having a cartridge barrel, an open end, a needle end to which the needle assembly is mountable, a piston within the barrel and a flowable pharmaceutical within the barrel between the piston and the needle end, the needle assembly having a tip, the syringe comprising:

• a main barrel having a proximal end, a distal end and a hollow interior sized to house the cartridge therein, the tip of the needle assembly extending past the distal end;
• a piston driver having a distal driver and engagable with the piston;
• means, operably coupled with the piston driver, for selecting a dose of the pharmaceutical to be dispensed through the needle assembly;
• first driving means for driving the tip of the needle assembly into a patient;
• and
• second driving means, separate from the first driving means, for driving the piston driver against the piston a selected distance, corresponding to the selected dose, after the first driving means has driven the tip of the needle assembly into the patient.