Seiko 9R65 Manual - Page 4

Spring Drive Mechanism ① Taste of a Mechanical Watch High accuracy equivalent to a Quartz Watch That is the concept of the Spring Drive. Let's start from the drive method of a watch. The method for driving a watch is divided into two types. They are mechanical type and quartz type. In a mechanical watch, the mainspring is wound and its unwinding power moves the hands. Amazing mechanism created by high quality workmanship, and admiration goes to skilled craftsmen with passion. You can feel the appreciation and personal touch of the craftsmen in the ticking sound. On the other hand, with quartz watches, the quartz is oscillated by a battery and the hands are turned by a motor. It is characterized by accuracy using state-of-the-art technology. What is the Spring Drive like? This is not a mechanical watch or a quartz watch. In one word, this is a"mechanical watch having accuracy equivalent to a quartz watch." The Spring Drive is a self-contained drive system that realizes accuracy equivalent to a quartz watch with only the power of the mainspring and has no battery, motor, or secondary battery. Accuracy of monthly rate of ±15 seconds (daily rate of ±1 second)※ equivalent to a quartz watch is achieved while using a mainspring. The Spring Drive is Seiko's proprietary mechanism which is made available only by SEIKO's unique combination of skills in both mechanical and electronic micro-engineering. Then, how could it be possible to achieve such a degree of accuracy? That is explained on the next page. ※ For Cal. 9R15, the average monthly rate is ±10 seconds (equivalent to daily rate of ±0.5 second). 4 Spring Drive Mechanism ② The power of the mainspring is regulated by electronic control. That is the essence of the Spring Drive. What controls the accuracy of a mechanical watch is the balance spring, a part of the speed-regulating unit, called the balance. This part influences the accuracy to some extent because it is made of metal which expands and contracts with changes in temperature. The Spring Drive is completely different from a mechanical watch in this speed-regulating unit. The Spring Drive is powered by a mainspring, but adopts an electronic speed-regulating unit comprising a generator, IC circuit, and crystal oscillator. In a little more detail, at the end of the train wheel that moves the hands, a series of speed increasing wheels with a rotor are provided. The unwinding power of the mainspring rotates the rotor, generating electricity in the coil to drive the crystal oscillator and IC. The IC controls the spinning speed of the rotor by applying and releasing the electromagnetic brake, while comparing the accuracy of the electric signals generated by the crystal oscillator and the spinning speed of the rotor. In addition, by making the energy transfer of the train wheel efficient and adopting an IC that drives with low power consumption and an amorphous core with low energy loss for the coil core part, power reserve of more than 72 hours far exceeding normal mechanical watches is realized. An unprecedented drive system which offers quartz accuracy. This is the Spring Drive. 5 English