GB764259A - Improvements in or relating to an assembly for a hypodermic injector - Google Patents

Abstract

764.259. Hypodermic injection devices. SCHERER CORPORATION, R. P. Jan. 31, 1955 [April 26, 1954], No. 2815/55. Class 81(2) A needleless injector has a plunger, having limited axial movement, mounted in an adjustable bearing member so that medicament can be ejected from an ampoule as a number of small injections, the plunger being advanced appropriately between doses. A bearing disc 50, Fig. 2 supports the plunger 40 by means of its stem 41, but the axial movement of the plunger is limited by its shoulder 44 and the face of a disc 43, secured to its inner end. The disc 50 cannot rotate relatively to the main body 10 but can be adjusted axially by turning an internally threaded sleeve 12 until the end of the plunger bears against the stopper 33 of the ampoule 31. When the striking member 66 is thrust against the disc 43 by release of the driving springs 64, the plunger 40 and stopper 33 are advanced a distance equal to the space 47. The disc 50 is then advanced a similar distance by the sleeve 12 prior to the subsequent use of the injector. Compression of the driving springs 64 is perfomed by rotating a screw 62 by means of a head 14, Fig. 1, and, since the screw engages threads 61 in a central extension of the head 66, Fig. 2, the latter is drawn towards the left. When the screw has been drawn back a sufficient distance a step 71, Fig. 1, is engaged by a rotatable latch 83 which is later released, for the injection, by a stud 80 bearing against a trip lever 25.