Seiko has been at the forefront of precision watchmaking for many decades. Amongst watchmakers, myself included, Seiko is known for its wonderful customer service, excellent value, and innovative products. For many people the name Seiko is synonymous with quartz technology, as it should be since they are the godfather of this know-how. But unknown too many is the role that Seiko has played in the advancement of mechanical timepieces. A prime example is the Seiko Diver’s Watch that is known for its reliability and performance under the most demanding of conditions. Many professional divers will wear nothing else while risking their lives in the ocean's depths.  

And so we come to the latest Seiko innovation, the Spring Drive. Although virtually all mechanical watches use a spring as a power source, the Spring Drive is extremely unique in that it dispenses with the 300+ year old idea of a mechanical escapement for the regulation of time. The result is a watch that avoids the age-old problems associated with mechanical escapements such as hairsprings, delicate balance wheels, pallet forks, and escape wheels (not to mention maintenance issues).   

The Seiko Spring Drive is a true mechanical watch - there is no battery to be replaced. At first glance you wouldn’t necessarily know this watch is anything exceptional, but after a closer look inside I’m sure you will agree that this is a true “Revolution in Time.”  

In this article you will be the first to see the inner workings of the Seiko Spring Drive. To be more precise, this is the world technical premier. You may click the images to view larger versions. Enjoy!

Please note that all watches and movements shown in this article are prototypes and not necessarily indicative of finished products.  

Why?  

So why is it that Seiko decided to develop a new generation of high-bred mechanical watches? First of all Seiko is a very technology driven company, always looking for better ideas and not afraid to try them. And let's not forget Seiko’s proud history of craftsmanship. Or maybe it’s the fact that the lever escapement, used in almost every mechanical watch for the past 200 years, is anything but perfect even after 200 years of constant development. And what’s wrong with the modern quartz watch? Well the quartz watch certainly lacks the romance of the mechanical watch, there is very little interaction between the watch and its owner other than changing the battery every year or so and adjusting for daylight savings time twice a year. Lets face it, quartz movements are ugly - how many times have you seen a display back on a quartz watch?!  

All in all I suppose it’s a combination of all these things and a desire to push the envelope... again.

How it Works 

I suppose a generality is in order to get things started. Most modern automobiles have speed control (cruise control). In which case the wheels of the automobile are controlled as not to spin too fast or too slow. With the Spring Drive the same basic technology is used to regulate the rate of the watch within 1 second per day. Believe me the Spring Drive technology is far more sophisticated than your cruise control!

A few technical notes might also be in order. The Seiko Spring Drive is an auto-wind mechanical watch that uses modern technology to regulate and measure time. It incorporates an auto winding mechanism and main spring similar to that of other mechanical movements. As mentioned earlier, a high tech system is used to regulate the measurement of time. Let’s have a closer look.

As shown above, the Spring Drive incorporates a newly developed main spring "A." This mainspring is made from an alloy developed by Seiko called Spron 510. This alloy makes the mainspring stronger, more flexible, and more resistant to corrosion. Seiko also applies a highly polish functional finishing to critical movement parts to reduce friction. This, combined with the use of Spron 510, results in a power reserve of 72 hours, which represents a 30% or 24 hour increase over other single barrel watches using standard mainsprings - a Seiko exclusive. This increased efficiency also allows for a simplified auto wind mechanism, reducing the number of components (reducing wear is always a good idea).

Main spring “A” is wound into barrel “B” with barrel arbor “C” inserted and capped with the barrel cap “D”. Attached to the outer end of the mainspring is the “bridle” “E” that slips on the inner diameter of the barrel much like the transmission of an automobile (excuse my continued reference to automobiles). If not for the bridle, the auto wind system could break the main spring by over winding, and/or damage the auto wind components.

A conventional “looking” auto winding mechanism is used to transfer wrist motion into mechanical energy by winding the mainspring. As shown above, eccentric rotor “A” is attached to rotor platform “B” at the center “C”.

From the bottom we can see the simplicity of the auto winding mechanism…

Unlike most modern auto winding mechanisms there are only three moving parts, excluding the eccentric rotor shown earlier. Seiko calls this the "magic lever" winding system. The center axle “A” transmits rotational energy from the eccentric rotor via an eccentric pin to the winding fork “B”. As the winding rotor is in motion, the winding fork either grabs or pushes the winding wheel “C” that is in direct connection with the main spring barrel. Due to the increased efficiency of the main spring, the Spring Drive auto winding system is as simple as possible, using 4 fewer components than usual.

Continue to Part 2 of the Article