GB805184A - Hypodermic assembly - Google Patents

Abstract

805,184. Hypodermic syringes. BECTON, DICKINSON & CO. Jan. 29, 1957, No. 3144/57. Class 81 (2). A hypodermic syringe comprises a casing which contains an ampoule closed at one end by a stopper and at the other end by a piston, the ampoule containing a hollow needle having an opening which is remote from the point and extends outside the ampoule beyond the piston, and means within the casing for projecting the needle through the stopper and piston so that the point extends from the ampoule and the opening is brought within the ampoule, whereafter the piston is moved to expel medicament through the needle. A transparent glass or plastic ampoule 27 having a rubber stopper 28 and a piston 29 is disposed in a polystyrene carrier 16. A hypodermic needle 30 is fixed in a plug 34 which is slidable in the rear of the carrier 16. The needle 30 extends through the ampoule piston 29, medicament in the ampoule 27 and the stopper 28, the needle point being located in a recess 31 in the stopper 28 and protected by a rubber layer 37 between the stopper 28 and a ring 36 which is fitted over the end of the carrier 16. An aperture 32 in the needle is located behind the piston 29. The carrier 16 is in the forward portion 11 of an aluminium outer easing. A spring 38 held compressed between arms 40 of a resilient metal mounting member is disposed in the rear portion 10 of the casing, the mounting member being held forwardly by a retaining sphere 48 so that portions 43 engage the bore of the casing and inwardly extending parts 41 of the mounting member prevent release of the spring 38. The sphere 48 is prevented from movement into a recess in the rear of the syringe by a safety-pin, the shaft 46 of which is gripped by narrow rear coils 45 of the spring 38. In use the safety-pin is removed and the syringe is pressed against the body so that carrier 16 moves rearwardly, thus pressing the spring mounting member rearwardly and moving the ball into the rear recess of the syringe. The portions 43 of the mounting member enter an enlargement 12 of the outer casing and spring apart so that the spring 38 is released. The spring 38 pushes forward the needle plug 34 and the needle 30, so that the aperture 32 enters the ampoule 27 and the needle 30 punctures the skin, and moves the piston 29 so that medicament is discharged from the ampoule 27 into the patient. In modifications, two springs arranged concentrically or in series may be used, one spring producing a sufficiently great thrust to dislodge the needle plug and the piston if they have slightly adhered during storage to the carrier or ampoule respectively. The ring 36 closing the forward end of the syringe may be replaced by a detachable cap and the carrier and ampoule may be made as a unit. A slot 63 (Fig. 10) may be provided in the ampoule stopper 60 through which is inserted a needle for filling the ampoule. The outer casing may be made in separable parts (not shown), the joints being covered by a sleeve of cellulose material.