The Winding Stem
Reference no 401
A clever invention by Patek Philippe in 1841 enabled one "button" to have the double function of both winding and setting the watch. The "button", mounted at the threaded end of the stem, is the winding crown. It serves the dual function of both winding the mainspring and, when necessary, setting the watch hands to the correct time.
The double function is achieved in a very clever way by letting a clutch wheel slide back and forth on the Winding Stem (401). The stem is square at the portion where the clutch wheel slides so the clutch wheel will turn when the stem is turned.
