Pawl 2 is connected by turning pairs D to the rim of wheel 1, freely rotating about shaft A, and to plunger 4 which is connected by turning pair E to piston 5. Piston 5 reciprocates in fixed pump cylinder 6. Hooked member 3 is rigidly attached to and rotates with shaft A. When shaft A rotates clockwise, member 3 engages pawl 2 and wheel 1 begins to rotate, pulling piston 5 upward until the shank of pawl 2 runs against fixed pin B. This disengages the pawl from member 3, and plunger 4 together with piston 5 moves downward by gravity.