Seiko

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Grand Seiko SBGE001 Spring Drive GMT

The Spring Drive is a watch movement that was developed by Seiko Epson through collaboration with Seiko Instruments and Seiko Holdings. To date, it is the only commercially available wristwatch embedded technology capable of truly creating a continuous movement of the second hand, instead of the traditional beats per time unit as seen in quartz or mechanical watches. It uses a mainspring, barrel, automatic winder and stem winding like in a mechanical watch to store energy. The conventional escapement is replaced with a device that Seiko calls a Tri-synchro Regulator to regulate the unwinding of the mainspring. The regulator controls the use of the three forms of energy used in the Spring Drive mechanism; the mechanical power of the mainspring, the electrical energy generated from this mechanical power, and the electromagnetic energy that governs the rotation of the glide wheel. The energy produced by the glide wheel is used to power a control circuit and quartz crystal oscillator, which in turn regulates the electro-mechanical braking of the glide wheel. The glide wheel’s speed is sampled 8 times per second (i.e. each time it makes a complete revolution around the regulator) and compared with the reference quartz signal by the circuit. A variable braking force is continuously applied to regulate the glide wheel’s frequency. This is the only movement with a time-only feedback (or phase-locked) loop in existence today. The Tri-synchro Regulator’s innovations result in a watch where the hands glide instead of ticking as in a conventional mechanical or quartz watch. This is because the movement never stops as in a traditional escapement; it is slowed to the proper speed by the brake. The movement is specified to 1-second accuracy per day. However, 1-2s per month is the norm. The quality of manufacturing and finishing is unsurpassed and sublimed. Using the best modern Japanese manufacturing technology can muster; Seiko also infused the traditional arts to make the end result something spectacular. The ancient art of Zaratsu “blade” polishing derived from the manufacturing the katana blade (or Samurai sword) has been utilized on the SBGE001.