Compound lever the force of pushing back the stick to the levers and they rub against the wheels, using friction to slow and eventually stop the train. These are everyday applications of this mechanism. A piano key is a compound lever of the first-class, since the fulcrum is between the weight to be moved and the power. The purpose of this lever is to translate a small movement (depression of the key) into a larger and fast movement of the hammer on the strings. The quality of the resulting tone depends on whether the final speed is brought about by gradual or
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