Emperador Cushion-Shaped 700P


Words: Gisbert L. Brunner
Photography: Hersteller, Alexander Bauer, Gisbert L. Brunner
Graphics: Eric Klein, Gisbert L. Brunner

The Swiss Watch Company makes an impressive return to the tradition of ultra-slim mechanical movement with the calibre 700P

That Piaget understands ultra-slim mechanical movements was amply proven when the traditional manufacture, with studios in Geneva and La Côte-aux-Fées (Fairy Hill), produced the calibres 9P, 12P and 1208P, and once again in 2014 with a further world record by the name of 900P. Not so well known is the fact that in 1968 Piaget acquired an interest in the C.E.H. (Centre Electronique Horloger) in Neuchâtel in order to use the quartz calibre Beta 21 for its own watches, starting in 1970.

In 1976 the (then) family company presented the world’s slimmest quartz movement, the 7P – just 3.1 mm high. Before this turning point quartz watches represented just five per cent of the company’s range. But then things changed dramatically. King Quartz assumed sovereignty over ever larger domains in the Piaget collection, with women especially prizing the blend of comfort and precision.

piaget calibres


At that time, several technicians and engineers were engaged with hybrid technologies that aimed at bringing good old mechanics and modern electronics together in one unit.

A number of participants at the 47th Congress of the Swiss Chronometric Society in mid-October 1972 – Messrs. Jean Claude Berney and André Guignard from Bernard Golay S.A., Lausanne, Jean Pierre Golay from Record Watch S.A., Tramelan, as well as Roland Dubois from Les Assortiments Réunis, Le Locle – seized the opportunity to introduce their new joint development, which they had christened “µ quartz” (microquartz).

golay Microquartz 1972

In this calibre, a quartz module with the usual 32,768 hertz rate served a disc-shaped balance wheel which, together with its spiral, set the pace at 28,800 vibrations per hour. To this end, an electronic frequency divider (flip-flop function) reduced the 32,768 hertz quartz frequency to four hertz, a factor of 8,162. The battery-operated electronics sat atop a classically constructed mechanical movement. Released in an edition of 3,000, the watch was not exactly showered in success, with the price of quartz technology with digital displays or stepping motors for analogue timepieces having come down considerably in the meantime.

And so Berney went back to the drawing board. What he had in mind was a hybrid without anchor escapement and oscillation system. He registered his new invention with the Swiss Federal Institute of Intellectual Property for the ébauche trust Ebauches SA on 21 November 1972. One year later, on 20 November 1973, the patent application was registered with the American authorities. It was approved on 10 February 1976. The Swiss patent was published on 14 April 1978.

Berney patent 1972

So was it a coincidence that in 1977, Yoshikazu Akahane presented the idea of a quartz watch without a battery to his employer, Seiko? At the time the Japanese engineer spoke of a cyclist riding sloping streets at a constant speed, focussing on the pace-setter – a hopping rabbit. However, huge problems arose when the company tried to turn the idea into a technical reality. It would be a full 22 years bfore the patented “Spring Drive” technology would go into production in Japan. And then in 2004 it was joined by the automatic variant.

Seiko Spring Drive Automatic Calibre 9R66A

Seiko Spring Drive Automatik Calibre 9R66A

But to return to Piaget – the spiritus rector of the brand new calibre 700P, which by the way has very little in common with the 7P, is Eric Klein. As head of the Richemont movement workshop ValFleurier, the creative engineer was responsible for the creation of the first Panerai calibre. He and his technical team were also involved with the development of the Montblanc “Rieussec” chronographs.

Eric Klein

Eric Klein

As Klein recently explained to me at the presentation for the 700 P, he had long been preoccupied with the Berney construction, for which a patent was filed in 1972. “This is a Swiss invention, and we wanted to revive it.” One reason for the return was that the movement accuracy had now become feasible. Another was the longevity and ease of servicing. You won’t find a classic lubricant-dependent escapement, and less force minimises the bearing pressure.

The calibre 700P, developed over two years for a limited run of 106 units, came with accuracy lost of just one second a day. Piaget CEO Philippe-Léopold Metzger told me that officially, the white gold “Emperador Cushion-Shaped 700P” is limited to just 118 pieces. Because the numbers 4, 14, 24…and so on up to 114 will be missing, due to the idiosyncrasies of potential Chinese customers, the edition is further limited.

Apart from the power regulating component, everything works just as it does in traditional automatic movements from a technical perspective, just as it did for Messrs Berney and Akahane. A tension spring, whether manual or automatic, stores the propulsion energy in the usual way. The connected gear-train also obeys the age-old laws of watchmaking, by converting the slow barrel rotations into faster rotations that nonetheless require less energy. Uniformly rotating hands display the time on the watch face. The power regulator, on the other hand, comes across as innovative. In mechanical movements, the anchor escapement, balance wheel and balance spring subdivide time with constant oscillation at a precisely defined pace.

Both Berney’s innovation and Seiko-Epson’s intelligent “synchro-regulator” resemble, in the broadest sense, a modern tram with eddy current brakes. Driven by the tension spring, a small magnet rotor constantly moves in one direction. With Seiko it completes eight rotations every second. In the case of Piaget the frequency sets a pace of 5.33 times per second.

Piaget 700P Function

The ensemble of coils and magnet rotors performs two tasks. On the one hand, it generates energy for the quartz-driven electromagnetic brake. Piaget saves the voltage thus produced in a small capacitor. The power sets the quartz oscillating. On the other, it allows the small chip, from Zurich specialists Microdul, to do its job. The electronic circuit constantly compares the high quartz frequency (32,768 Hz) with that of the 16 hertz of the power regulator, divided by the flip-flop function. Where there are deviations, the electronics intervene to regulate and correct.

In the Piaget 700P, a gap of just 0.12 millimetres separates the six coils, four for the generator and two for the brake, and the 1.3 Tesla magnet rotors, made from an alloy of neodymium, iron and boron. This means that the tolerances in the assembly are tightly controlled. One movement takes the specialists involved one whole day.

Piaget 700P Function
Piaget 700P Function

With the very low edition and the high cost of development and production, the pleasure of being able to call the smart, luxurious “Emperador Cushion-Shaped 700P” your own doesn’t exactly come cheap. Philippe-Léopold Metzger mentioned a world price of 70,000 Swiss francs to me. And that doesn’t include country-specific taxes.

Philippe-Léopold Metzger
Piaget 700P

In the meantime, Eric Klein is already working on the next stage in the evolution of the multi-patented 700P. A temperature-stabilised quartz oscillator is set to reduce the movement deviation to just 10 seconds a year. And in this case, larger production runs and correspondingly lower prices are a distinct possibility.

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01 2016 The Red Bulletin

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