GB705515A - Hypodermic jet injector - Google Patents

Abstract

705,515. Hypodermic injectors. SCHERER CORPORATION, R. P. March 19, 1951, No. 6520/51. Class 81(2) A hypodermic jet injector includes a body assembly holding an ampoule with a closure member therein, a primary and a secondary plunger slidable in said body so as to engage and propel the said closure member to discharge liquid from the ampoule, through an orifice therein, at two different sequential pressures, both of the plungers being propelled by spring means operable upon a nut slidable in said body assembly, there being a screw threaded in said nut with a releasable means for latching said screw against longitudinal movement and winding means for rotating said screw relative to said nut. As shown in Figs. 4 and 5, five springs 111, of which only one is shown, are spaced around a central screw 110 which engages in a threaded portion of a sleeve-shaped nut 100, the springs seating in one end in seats 103 formed in the nut 100 and at the other end against a partition 112 formed in the body of the device. Depression of a button 61 causes latch mechanism 54, 66 to release the portion 115 of the screw 110, which, together with nut 100, is propelled to the right, causing a primary plunger 80 to act on the closure member 73 of ampoule 72 so as to expel liquid therefrom at a high pressure. Continued movement of the nut 100 and screw 110 then forces a secondary plunger 90 against the closure 73 so that liquid continues to be expelled but at a lower pressure; at the end of the injection the parts assume the position shown in Fig. 10. To prepare for re-use a winding sleeve 40 is first rotated anti-clockwise until the rear portion of the screw is again held by the latch mechanism 54, 63, and then rotated clockwise so as to draw the nut 100 to the rear and compress the springs 111. Means are provided for varying the quantity of liquid injected and for varying the proportions injected at the higher and' lower pressures. Specification 681,098 is referred to.