Grasshopper escapement to Harrison were poor, messy and short-lived. This meant that conventional clocks had to be stopped frequently for cleaning and oiling. Using his clean and absolutely stable grasshopper escapement Harrison began a series of long-term investigations into the performance of clocks, leading to his invention of the gridiron pendulum which counteracted the effects of expansion and contraction with changing temperature. The performance of his improved clocks in turn gave him an accurate, convenient standard against which to test his marine timekeepers. Harrison developed the grasshopper escapement from a conventional anchor escapement which he built for a turret clock to go
Grasshopper escapement in the stable block at Brocklesby Park in Lincolnshire. This proved to be unreliable, needing repeated attention by which Harrison was inconvenienced, so around 1722 he modified the escapement by putting a hinge in the middle of each arm of the anchor. The hinged pallets both pointed the same way, opposing the rotation of the escape wheel. As the escape wheel pushes the pallet, the hinge moves away from the escape wheel. The pallet pivots about its contact point with the wheel as it pushes the anchor. At the same time, the other pallet is approaching the wheel. When it