Hydraulic jigger

This was generated centrally and distributed by pipework, either around a dock estate, or across a city by the new hydraulic power networks.

The chain is looped several times lengthwise around the ram cylinder, running over a number of pulleys at each end.

As the cylinder had adequate power to begin with, and could simply be made larger in diameter when needed, this was not a significant limit on the jigger's force.

Loaded, heavy, lifts were made by the conventional cylinder, its diameter sized according to the maximum capacity.

[4][i] The basic jigger mechanism was used very widely, for a range of machines across dockyards, warehouses, railway yards and engineering workshops.

These could be moved around the quays as needed, and plumbed into outlets in the hydraulic mains with screwed pipe unions.

Bales of bulk products such as jute or cotton were made too large and heavy for dockers to lift by hand, and the jigger appeared at a time when cranes were still only in limited numbers.

[3] These were not accepted for passenger carrying though, until 1854 and Elisha Otis' invention of the safety brake, to prevent the carriage falling if the hoisting cable were to break.

The average acceleration for an aircraft was 1 g, with a peak of 2.5 g. After launching, the piston was decelerated within the cylinder by a conical protrusion entering a narrow choke ring, and the hydraulic resistance increasing as the flow area reduced.