While I have always appreciated the GS line and Spring Drive, this exercise/content was nice as it allowed me to consolidate my understanding.
When the mainspring unwinds, it moves the gear train, which in turn advances the hands of the watch. This process needs to be regulated so that the gear train and, therefore, hands advance at an accurate and meaningful pace to keep time.
In traditional mechanical watches, regulation is done by the hairspring / balance wheel, which beats at a predetermined set rate. This rate is translated via the escapement, which acts a “brake” on the gear train. It is this braking action that effectively regulates the system.
The Spring Drive replaces the escapement and oscillating balance wheel in favor of the Tri-Synchro Regulator. The Tri-Synchro Regulator consists of a glide wheel and quartz oscillator, which are connected by a circuit. The glide wheel is connected to the gear train, and, as in a traditional mechanical watch, if unregulated they would both rotate quickly and arbitrarily. However, the glide wheel’s rate of rotation is sampled via the circuit and is subsequently slowed down to 8 rotations per second, as determined by the quartz reference beat, via an electromagnet. Because the glide wheel is now regulated and is connected to the gear train, the hands advance purposefully for accurate time-keeping.