Pushing Pistons

Various kinds of counterweight -- water and otherwise -- were attempted but found to be bulky and expensive. Required was a relatively simple design that would multiply the force of the plunger and steam power. The single sheave exited quickly and the double sheave with one at the cylinder and the other being pushed came into vogue. These occupied a reasonable amount of space and were provided with one or two pistons. Within a short time, valve functions were refined, operated from the car’s tiller cable and allowing the operator to change direction of travel. Limit switches at either end of the piston runway were arranged to shut off the water at the extent of the run. The pull type roped water hydraulic proved its worth for the moderate speed passenger elevators so many of which were being required by the spread of multi-level commercial buildings.