Mechanical clocks and watches use the spring as the power of the driving system, through a group of gears to drive the escapement governor; then the escapement governor controls the speed of the transmission system in turn; while driving the escapement governor, the transmission system also drives the pointer mechanism, the speed of the transmission system is controlled by the escapement governor, so the pointer can indicate the time on the dial according to certain rules. The upper dialing needle system is a mechanism for tightening the spring or pulling the pointer.