Multi-dose needle-less hypodermic jet injection device

Abstract

Abstract 959,397. Hypodermic syringes. A. ISMACH. Oct. 26, 1960 [Dec. 14, 1959], No. 36830/60. Heading A5R. A needleless hypodermic syringe has a rear chamber 10 and a forward medicament chamber 39, a piston 12 movable rearwardly in the rear chamber against a bias by hydraulic fluid directed into the rear chamber, a plunger 36 reciprocable in the forward chamber and responsive to movement of the piston and means for releasing hydraulic fluid from the rear chamber. Hydraulic fluid normally circulates continuously from a pump (not shown) through a normally open loading valve 78. On depressing a cocking trigger 74 mounted on a handle-grip 21, the valve 78 is closed so that hydraulic fluid flows through a conduit 87 to open a check valve 82 and thence into the rear chamber 10. The fluid moves the piston to compress a spring 16. The plunger 36 which is detachably secured to the piston is moved rearwardly so that medicament is drawn from a bottle 58 into the forward chamber 39. On releasing the cooking trigger, hydraulic fluid again circulates through the loading valve 78. On depressing a firing trigger 76, a release valve 86 opens and fluid flows from the rear chamber to the pump thus releasing the spring 16 so that the piston and plunger are projected to eject medicament through an outlet valve 44 and an orifice in a sapphire insert 46 in the syringe nozzle. The stroke of the piston and plunger, and thus the volume of medicament drawn into and ejected from the medicament chamber, may be adjusted by a screw 24 which adjusts the position of a thrust ballbearing 26 against which the spring abuts. The bottle 58 is supported on the body of the syringe. Medicament passes from the bottle to the medicament chamber by way of an extraction pipe 54, a check valve 48 and an inlet tube 52. Medicament in the bottle is replaced by air passing through a filter 60 and a tube 55 part of which is concentrically arranged inside the extraction pipe 54. Specifications 798,826 and 798,827 are referred to. Reference has been directed by the Comptroller to Specifications 798,826 and 798,827.

Inventors

No inventors recorded.

Bibliographic Details