grasshopper escapement: a standalone construct

The grasshopper escapement is a low-friction clock escapement invented by John Harrison in the early eighteenth century, in which two pivoted arms alternately catch and release the escape wheel with a kicking motion that reminded observers of a grasshopper's legs. Because the contacting parts move together at the moment of engagement there is almost no sliding friction, so the escapement needs little or no oil, a real advantage before good lubricants existed. Gould's The marine chronometer (first published 1923) describes Harrison's use of it. It is a distinctive but largely self-contained chapter of horological design.[1]

Unit

A near-frictionless clock escapement

Recovery means

Not applicable

Measured by

Judged by its very low sliding friction and near-oil-free running