Variable-stroke reciprocating pumps

1,149,273. Linkwork; valves. NIPPON KIKAI KEISO KAISHA Ltd. 23 June, 1966 No. 28223/66. Headings F2K and F2V. [Also in Division F1] In a variable stroke pump having a crankshaft 1 rotatable with and axially adjustable relative to a rotary sleeve 8 with a worm wheel 10 engaged by a driving worm 11, a member 2 mounted on the crank 51 and fixed axially relative to the sleeve is coupled to a pumping plunger or a plunger actuating a pumping diaphragm through a body of liquid. The crank 51 may be circular, square or rectangular in cross-section and the corresponding aperture 54 in the disc-shaped member 2 may be at the centre of the member or eccentric. An overhung crank-shaft (1), Fig. 6 (not shown), may be provided. The lead screw 4 of the crank-shaft 1 may be rotated by a hand wheel 18 and/or an electric or pneumatic servomotor. A diaphragm pump may be provided with a reservoir (75), Figs. 13 and 14 (not shown), of actuating liquid which is placed in communication with its displacement liquid chamber (73) by means of a valve (84) in the reservoir. The valve (84) is coupled to a piston (77) actuated by liquid displaced by a plunger (89) operated by a cam (72) on the rotary driving sleeve (8) of the pump. Liquid may be fed to the circuit (88) of the piston operating plunger (89) through a ball valve (94) or a narrow passage (901), Fig. 17 (not shown), in the valve piston (77).