Movement No. 86 demonstrates a clever method of driving a reciprocating pump using continuous rotary motion. A wheel (A) sits loosely on a rotating shaft and is connected to the pump-rod via a rope. The shaft continuously rotates and carries a cam (C). On each revolution, the cam engages the hooked catch (B) fixed to the wheel, dragging the wheel around with it and winding up the rope — thereby lifting the pump-rod. When the tip of the catch strikes a fixed stationary stop, the catch is released, freeing the wheel. The weight of the pump bucket then pulls the rope back down, returning the wheel to its starting position and completing one pump stroke. This cycle repeats with every revolution of the shaft.
86. A method of working a reciprocating pump by rotary motion. A rope, carrying the pump-rod, is attached to the wheel, A, which runs loosely upon the shaft. The shaft carries a cam, C, and has a continuous rotary motion. At every revolution the cam seizes the hooked catch, B, attached to the wheel, and drags it round, together with the wheel, and raises the rope until, on the extremity of the catch striking the stationary stop above, the catch is released, and the wheel is returned by the weight of the pump-bucket.