GB138144A - Improvements relating to medical and dental syringes - Google Patents

Abstract

138,144. Ostrov, A. L. June 30, 1919. Syringes.-In a hypodermic syringe of the type adapted to be filled through a hollow piston-rod provided with one or more valves, the valves are adapted to be held open pcsitively against the action of one or more springs during the filling-operation. In the form shown, the syringe comprises a plain or graduated glass barrel 1 mounted within a fenestrated guard 2 terminating in a cap 11 formed with arms 12. The upper end of the barrel is closed by a plug 7 fitted with a non-return ball valve 10 and screwed to a nozzle 9. The piston comprises packing 26 secured between flanges on a member 4 consisting of two parts screwed together. The hollow piston-rod 5 is screwed to an extension of the member 4 and encloses a valve stem 14 surrounded by a sleeve 21 and fitted with valve members 13, 15. The valves are normally closed by a spring 22 surrounding the sleeve 21. The handle 6 is formed with a bore 18 normally closed by a pivoted cover 20. The syringe is charged from a bottle 23 fitted with an outlet pipe 24 fitting closely within the bore 18 and adapted to engage a ball 17, and so raise the valve stem 14 and open the valves, whereupon, on retracting the piston, liquid is sucked into the barrel. The valves are closed by the spring 22 immediately the nozzle 24 is withdrawn. In a modification, the valve member 15 is omitted. The nozzle employed is preferably that described in Specification 104,537. In dental work, a tubular projection extending considerably beyond the end cap is employed, so that the needle is sufficiently distant from the nozzle end of the springe to avoid placing the syringe in the mouth of the patient.