THE KEYLESS WORKS
Patek Philippe caliber 240-PS

The illustration reveals the beautifully crafted keyless works of the contemporary Patek Philippe caliber 240-PS. It was Antoine Philippe who, in 1841, developed the concept of the keyless works that is still in use today. Before that time, winding and hand-setting were done with a separate key. (1) The cover (or bridge). (2) The setting lever (pull piece). (3) The clutch return lever. (The clutch, winding pinion, and stem are removed in this photograph.)

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