Anchor escapement clocks. During the 19th century the deadbeat form gradually took over in most quality clocks, but the anchor form is still used in a few pendulum clocks today. The anchor escapement is reliable and tolerant of large geometrical errors in its construction, but its operation is similar to the old verge escapement, and retains two of the major disadvantages of the verge: The above two disadvantages were removed with the invention of an improved version of the anchor escapement: the deadbeat or Graham escapement. This is often erroneously credited to English clockmaker George Graham who introduced it around 1715 in
Lever escapement the escape wheel must recoil a small amount during the unlocking. The draw holds the lever against the banking pins during the detached portion of the operating cycle. Draw angle is typically about 11-15 degrees to the radial. Early lever escapements lacked draw (indeed some makers considered it injurious as a cause of extra friction in unlocking); as a result a jolt could result in the escapement unlocking. Most modern mechanical watches are jeweled lever watches, using manmade ruby or sapphire jewels for the high-wear areas of the watch. A cheaper, less accurate version of the lever escapement is used