1980: true to its philosophy of always remaining at the forefront of the watchmaking industry, the Corum brand creates the Golden Bridge model, a watch featuring a remarkable and totally new “baguette” movement.
2011: having just celebrated its 30th anniversary, the Golden Bridge has become one of the pillars of the Manufacture, and an icon of Swiss watchmaking. Now available in a variety of models, it is the subject of two new variations that once again highlight its ultra-innovative
character.
Golden Bridge Tourbillon with sapphire bridge
To bring innovation to its iconic model, Corum chose to work on the baguette movement with tourbillon escapement. The work on its aesthetics began with a veritable technical tour de force. Part of the bridge of the CO213 movement – usually made entirely of solid 18-carat gold – has been replaced, at the tourbillon cage, by a transparent sapphire part. One of the major challenges of this operation was to ensure the coexistence of two materials with different hardnesses, rigidities and coefficients of expansion: sapphire and
gold. The stresses involved are all the greater for a baguette movement, and the difficulty to overcome is all the more obvious given that the sapphire bridge is only 0.6 mm thick. While one end of the sapphire plate has been screwed to the gold bridge in the usual way, the other, cut to a point, simply fits into the second part of the gold bridge, which has been machined into a V-shape.
Thanks to this new configuration, the flying tourbillon cage of the latest Golden Bridge, now held in place by a transparent piece of crystal, becomes perfectly visible and even more ethereal. Its key-shaped upper bridge, a Corum hallmark, and all the moving components of its silicon escapement can thus be admired. The solid gold dial, entirely guilloché by hand, is placed, contrary to watchmaking custom, not in front but behind the movement. It is openworked so that the CO213 caliber can also be seen from the back of the watch. The case of this Golden Bridge Tourbillon model offers maximum transparency, allowing the aerial movement to be admired from either side of the case middle. No fewer than four sapphire crystals are required to build a case – water-resistant to 30 meters –
that resembles a showcase containing a precious object. Such an exceptional timepiece is naturally subject to an extremely limited production run. Only 10 in white gold and 15 in 18-carat red gold will be offered to collectors and enthusiasts of this exceptional collection.
Ti-Bridge Power Reserve
The second novelty presented by Corum is the Ti-Bridge Power Reserve watch. The Ti-Bridge, with its distinctive titanium case and horizontal baguette movement held in place by four ruthenium-coated flanges, is a contemporary interpretation of the Golden Bridge spirit. This unique timepiece, a blend of sobriety, modernity and elegance, presents a perfect balance between design and technology. The hand-wound baguette movement that powers the latest Ti-Bridge – caliber CO107 – displays the hours, minutes and – a first for the collection – the power-reserve indication.
For this highly architectural watch, a linear display of such a function was essential.
To achieve this, the CO107 caliber is fitted with a satellite gear train, visible when the watch is viewed at an angle, in the 9 o’clock / 3 o’clock axis, but invisible when the Ti- Bridge is viewed from the front. This module has a number of special features, including a three-wheel differential system, including an eccentric “planetary wheel”. Depending on its direction of rotation, the latter rotates either around its own axis, or around the axis of the other two wheels, thus linking the barrel on the one hand, the winding stem on the other, to the power reserve indicator, all in a minimum of space. Another special feature developed for this caliber: the power-reserve indicator is mounted on a sliding toothed part made of nickel phosphate. The choice of this material, combined with a “LIGA” manufacturing process – from the German “LIthographie, Galvanik und Abformung” – akin to electroforming, results in a part with much more precise dimensions than those obtained through conventional mechanical machining. This guarantees the extreme precision of the power reserve indication, which in this case amounts to 3
days. The new Ti-Bridge Power Reserve features a grade 5 titanium case and titanium dial. The hour and minute hands, as well as the power reserve indicator, are coated with luminescent material for perfect readability in the dark. Mounted on a rubber strap fitted with a folding clasp with two safety push-pieces, the Ti-Bridge Power Reserve is offered in a limited series of 700 numbered pieces.
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