Automatic hypodermic syringe

Claim 1

A HYPODERMIC SYRINGE OF THE TYPE COMPRISING A CARTRIDGE HOLDER ADAPTED TO RETAIN A MEDICATION CONTAINING CARTRIDGE, SAID CARTRIDGE HAVING A PISTON MOVABLE LONGITUDINALLY THEREOF TO EXPEL THE MEDICATION THEREFROM, AN INJECTOR GUN HAVING A BARREL WITH AN END WALL AND MEANS FOR COUPLING THE BARREL WITH THE CARTRIDGE HOLDER AND A PLUNGER MOVABLE LONGITUDINALLY THEREOF, DRIVE MEANS WITHIN THE INJECTOR GUN FOR URGING THE PLUNGER TO PROJECTED POSITION FOR ENGAGEMENT WITH THE PISTON AND TRANSPORT THEREOF ALONG THE LENGTH OF THE CARTRIDGE, DETENT MEANS HOLDING THE PLUNGER AGAINST MOVEMENT, RELEASE MEANS OPERATIVE ON SAID DETENT MEANS TO RELEASE THE PLUNGER TO THE ACTION OF THE DRIVE MEANS, AND SAID MEANS FOR COUPLING THE BARREL WITH THE CARTRIDGE HOLDER COMPRISING A QUICK DETACHABLE COUPLING BETWEEN THE HOLDER AND THE END OF THE BARREL WHICH COUPLING MAINTAINS THE HOLDER AND INJECTOR GUN IN LONGITUDINAL ALIGNMENT, THE LENGTH OF THE PLUNGER BEING SUCH THAT IT EXTENDS BEYOND THE BARREL END IN BOTH THE PROJECTED AND WITHDRAWN POSITIONS OF THE PLUNGER, AND MEANS ON THE PLUNGER ENGAGING THE END WALL OF THE BARREL TO LIMIT THE PROJECTING MOVEMENT OF THE PLUNGER SO AS TO PREVENT COMPLETE EXPULSION OF THE PLUNGER FROM THE BARREL.