GB909898A - Improvements in or relating to a device for automatically effecting injections with a hypodermic syringe - Google Patents

Abstract

909,898. Surgical injection appliances. LEWIS, D. T. April 14, 1959 [April 17, 1958], No. 12622/59. Class 81 (2). An automatic hypodermic syringe has a single spring for first projecting a syringe carrier and then, by its continued movement, expelling the contents. The syringe 6 is held in a carrier 5 which has attached to it a releasable catch 22, normally engaging a recess 21 in a spring-loaded rod 14. When this rod is drawn back, as shown, the spring 29 is compressed against the interior of the casing 4. Release of the carrier 5 by a trigger assembly 3, 26 allows it to be driven forward so that the needle 8 is projected into the patient and, when it reaches the limit of its travel, the latch 22 is released by a cam surface 32. The rod 14 is then driven further by the spring 29, and, by means of a bridgepiece 16 and rod 17, it forces the plunger 10 inwards to expel the contents of the syringe.