Even Lange's patent drawings are things of beauty. This patent, which expired in September, 2016, discloses and claims a beautifully simple mechanism to zero a second hand while setting the time.
The basics of this mechanism is a cam-plate drive. The cam plate can be seen attached to the seconds stem. When the crown is pulled into the setting position the cam is driven by a spring-driven lever into the zero position. By using a heart-shaped cam, the mechanism will also hack - keep the second-hand at the zero position while the minute hand is being set.
For such a desirable feature, there are surprisingly few parts involved, and given that the patent on this mechanism has expired, I'd love to see to lower-end watch companies start to incorporate this into their watches.