A liquid pumpjack. The 4-bar mechanism converts continuous rotation to reciprocating rotation that the cable drive converts to reciprocating translation of a pump piston.
The ball valves open and close automatically due to fluid pressure alteration in the space under the piston.
When the piston moves up, the lower valve opens, the upper valve closes. The outside liquid is sucked into the space under the piston. The liquid above the piston is pushed up.
When piston moves down, the lower valve closes, the upper valve opens. The liquid is pressed from the space under the piston into the space above the piston.