GB1327024A - Syringe gun - Google Patents

Abstract

1327024 Reciprocating pumps COOPER McDOUGALL & ROBERTSON Ltd 16 Sept 1970 [16 June 1969 6 June 19701 30304/69 and 27465/7 Heading F1A [Also in Division A5] A hand-actuated pump for dispensing measured doses of liquid e. g. vaccine for animals, comprises a bucket piston 3 with a valve 16 controlling flow through the piston rod 2 into the cylinder 1, and an outlet valve 9 on the cylinder. As shown, the outlet valve comprises a resilient disc, e. g. of rubber, supported by castellations 11 so as to close the port 7, and the inlet valve comprises a flexible flap 16 integral with the piston 3. Alternatively, the piston valve may be the same as the valve 9, Fig. 6 (not shown), and the outlet valve may comprise a resilient disc with peripheral holes or notches supported so as to be biased to close port 7, and forced away from port 7 by the delivery pressure, Figs. 7 and 8 (not shown). The piston stroke is set by a plate 19 which is slidable transversely of the cylinder to engage piston rod stop 17 in the position shown, and piston rod stop 18 when slid to the left, the piston rod and the plate aperture 20 being of rectangular cross-section. In Fig. 5 (not shown), the stroke is set by a sleeve adjustably screw threaded in a member secured to the upper end of the cylinder, the sleeve being movable axially of the cylinder to limit the outward movement of the piston which is spring-biased outwardly. Alternatively, stroke control may be effected by a projection on the piston rod engaging a slot in the cylinder, or a projection on a sleeve slidably clamped to the cylinder. Cylinder flanges 22 form finger grips, thumb pressure being applied to member 5 to effect the discharge stroke. A lock nut 13 secures a needle on outlet 12.