The 1270P caliber – one of the latest, thinnest and a very beautiful automatic movement
In the beginnings, when I was young and inexperienced, I believed that automatic watches are a new thing, coming from the modern ages… I was terribly wrong! But then I started to discover watches older than me and much older than that with self-winding. The second surprise was the micro-rotor (explained later) – that I first discovered in Piaget some years ago and I thought to myself that is a good idea, at last, the modern miniaturization can find a solution for the big wing that covers almost half of the mechanism. And I was so wrong again, even worse than the first time. So I decided to find out a little bit more about it.
The automatic (self-winding) calibre permits the wounding of the mainspring through the motion of the wearer. This system makes possible that on a normal wear to skip the need of the manual winding and have enough energy in the spring for a continuous operation of the movement even if the watch is not used during the night or for a longer time (for those with great power reserve).
The history of the automatic / self-winding mechanism for watches is rich and since the first/true inventor is somehow hard to be recognized and the literature is vast I will give at the end some links and recommendations.
At the beginning of 1777, Abraham-Louis Perrelet used an oscillating weight mounted in a pocket watch (Montre a Secousses), with an up / down movement permitting a full winding in 15 minutes of walking. He later used this principle to invent the pedometer.
In the same period, Hubert Sarton presented another series of drawing based on the principle of a rotor, that seemed to be an improved version of Perrelet’s design.
Abraham-Louis Breguet improved Perrelet’s design and used it in his pocket watches.
In 1922 Leroy (L. Leroy and Cie) created the first automatic wristwatch for Sir David Salomons. Unfortunately, I didn‘t find very much information about it.
In 1923 John Harwood patented an oscillating winding weight which contained at the ends spring-loaded buffers, the system being closer to what we know today (rotor look alike). This system was known as ‘bumper’ watches and it only wounded at a clockwise movement.
This design was used by several companies and is usually met in the 40’s and 50′ automatic movements of Omega, Eterna, Movado, Jaeger-LeCoultre, Fortis etc
In 1955 Universal Geneve integrated into the Calibre 215 the first of-centric planetary rotor, a micro-rotor. The brain behind the patent n.329805 was Charles Gérald Genta.
Universal Geneve Caliber 215 with the micro-rotor
Heuer Caliber 11 with Buren micro-rotor used in Heuer Monaco
Fortis F2001-5 Automatic Alarm Chronograph
Now, automatic movements are required more by the regular users and pushed the development even more by creating the Automatic Quartz – a hybrid – a quartz movement powered by a micro electric generator actuated by a classical rotor mechanism and a capacitor as an energy store. This solution combines the beauty of the mechanical rotor (many times visible through the crystal back) with the precision of the quartz resonator without the environmental issues of batteries. This type of movement is named Auto-quartz (name used including by ETA).
One of the first manufacturers was Seiko (Kinetic movement).
Seiko Kinetic 5M42 calibre
The automatic movements are in any version a nice to have featured in any watch especially when this is visible through the back or even from the front (aesthetic reasons).
Some are considering this a complication, others don’t, so I guess it is a matter of taste. For me this is the most important feature of a watch.