Hand operated metering pump - has adjustable locking ratchet which sets volume pumped and has two stage movement

摘要

The pump has a piston (2) reciprocating in a cylinder (1). The piston is on the end of a rod (3) which runs through a guide sleeve (5b) which itself terminates in a guide head (5a). A lever (8) pivoting on the end of the rod and sliding on the guide head (5a) enables the rod to be moved a fixed amount in the sleeve. The sleeve carries a ring (6) which trips over pivoting ratchet arms (7) on the inside of the casing (12). These arms fix the movement of the sleeve which carries the piston rod with it for the first stage displacement. They can be adjusted in position on the casing to vary the movement and thus alter the volume metered and pumped.