Anchor escapement the anchor is aligned with the bending point of the spring. This arrangement results in a more stable pendulum support than simply suspending the pendulum directly from the anchor. The anchor is very tolerant of variations in its geometry, so its shape varied widely. In late 19th century, in Britain, the usual design was a 90° angle between the pallets, which meant locating the anchor pivot a distance of ≈ 1.4 times the escape wheel radius from the escape wheel pivot. In a grandfather clock, which had a pendulum which swung once per second, the escape wheel often had 30
Escapement patented it in 1782. The early forms had two escape wheels. The duplex escapement was difficult to make but achieved much higher accuracy than the cylinder escapement, and could equal that of the (early) lever escapement and when carefully made was almost as good as a detent escapement. It was used in quality English pocketwatches from about 1790 to 1860, In the duplex, as in the chronometer escapement to which it has similarities, the balance wheel only receives an impulse during one of the two swings in its cycle. The escape wheel has two sets of teeth (hence the name