Seiko’s Spring Drive Caliber 5R

SPRING DRIVE

The Ever-Lasting Watch

In 1977, a young Seiko engineer, Yoshikazu Akahane, endeavored to make his dream of “the ever-lasting watch” come true: a watch wound by a mainspring but with a precision that only the finest electronic watches of the time could deliver. It took him 28 years, countless setbacks and over 600 prototypes, but Akahane and his team finally succeeded and, in the process, invented new technologies in nearly every aspect of watchmaking. Thanks to these advances, in 2005 Seiko Spring Drive came of age with an unparalleled accuracy and durability, its unique gliding second hand expressing the natural and continuous flow of time.

Unparalleled Technology

One of the most innovative developments in watchmaking in 200 years, Spring Drive is an automatic mechanically driven movement that can achieve the accuracy of a quartz watch, +/- 1 second a day (+/-15 seconds per month). The functionality of Spring Drive starts at the mainspring like any mechanical watch, but it uses a very unique escapement system. Since Spring drive is mechanically powered, there is no battery, capacitor, or storage of electricity – any electricity generated is used immediately. This ground-breaking movement has around 100 more components than a standard automatic watch and has higher longevity because there is no collision or friction in the escapement.

Developed For High-intensity Timekeeping

While the motive power is in the mainspring, the traditional escapement is replaced with the tri-synchro regulator which uses electromagnetic energy to transmit power to the gear train, control the speed of the glide wheel and generate electricity to oscillate its own crystal. The result is enhanced stability, durability and precision, with increased shock- and temperature-resistance, and a power reserve of 72 hours. A perfect choice for high intensity timekeeping, Seiko Spring Drive watches have been worn both in space at the International Space Station and atop Mount Everest.

SPRING DRIVE

CALIBERS 5R65 AND 5R66

Winding mechanism	Automatic with manual winding mechanism
Power reserve	Approximately 72 hours
Accuracy	±1 seconds per day (±15 seconds per month)
Number of jewels	30 jewels
Features	Date calendar and power reserve indicator (5R65 and 5R66), GMT hand (5R66)