Escapement spring made accurate timepieces possible, it has been estimated that more than three hundred different mechanical escapements have been devised, but only about 10 have seen widespread use. These are described below. In the 20th century, electric timekeeping methods replaced mechanical clocks and watches, so escapement design became a little-known curiosity. The earliest mechanical escapement from about 1275) was the verge escapement, also known as the crown-wheel escapement. It was used in the first mechanical clocks and was originally controlled by a foliot, a horizontal bar with weights at either end. The escapement consists of an escape wheel shaped somewhat
Mechanical watch the watch from its time source, the balance spring, watches could be built without a fusee and still be accurate. In the 18th century the original verge escapement, which required a fusee, was gradually replaced in better French watches with the cylinder escapement, and in British watches with the duplex escapement. Then in the 19th century both were superseded by the lever escapement which has been used almost exclusively ever since. A cheaper version of the lever, the pin lever escapement, patented in 1867 by Georges Frederic Roskopf was used in inexpensive watches until the 1970s. As manual-wound mechanical watches