Arnold & Son apply Constant Force
The Constant Force Tourbillon timepiece belongs to the Royal Collection from Arnold & Son and was showcased at Baselworld in March, 2015
John Arnold, the founding father of the brand was on a continuous quest in search of the perfect precision mechanism for his timepieces. He believed; the more accurate the chronometer, the more precise the calculation of longitudinal, east and west, position was at sea. Arnold and his son mastered the technique to achieve this and were the first to develop and produce technically superior marine chronometers in substantial quantities. Now in 2015, precision chronometry is pushed even further with the Constant Force Tourbillon that features a patented constant force device with 60-second tourbillon and true beat seconds, also known as jumping seconds. The architecture of the movement is a homage to Arnold & Sons’ historic marine chronometers, which were first produced in 1770.
Similar to every Arnold & Son timepiece, the new 2015 edition is energised by an in-house built mechanism that has a power reserve of 90 hours. The mechanical hand-wound A&S5119 movement is housed in an 18-carat red gold case with anti-reflective sapphire crystal. Measuring 46mm in diameter, the Constant Force Tourbillon watch features two visible mainspring barrels and a constant force device at the top of the dial that provides optimal power to the tourbillon at the bottom of the dial by maximizing power consistency. The mainspring barrel is the source of the movement’s power, where instead of using just one mainspring barrel, which would produce considerably different amounts of torque between fully wound and nearly empty, the Constant Force Tourbillon has two symmetrical barrels in series that are positioned at 10:30 and 1:30. The first mainspring barrel powers the gear train, while the second barrel tops up the first whenever its torque output drops below optimal. This allows the power to the regulator to flow as smoothly and continuously as possible. Should the power from the mainspring drop at any time, the movement is designed to stop rather than running at lower, more inaccurate precision.
The constant force device rotates once per minute in increments of one second, almost mirroring the rotation of the continually rotating tourbillon cage. The bridges supporting the constant force regulator and tourbillon are also designed symmetrical, both horizontally with each other and vertically with the barrel bridges. However, although both the Constant Force and Tourbillon rotate, there is one significant difference; the former optimizes precision with the movement in a stable position in increments of one second, while the 60-second tourbillon reduces gravitational inaccuracies on the escapement by constantly rotating through 360°. The revolutionary concept of the Constant Force and Tourbilion is supported on an anthracite open dial that boasts a black outer ring with white indexes and red gold hour markers that are pointed to by red gold hour and minute hands. The Constant Force Tourbillon is a limited edition of 28 timepieces, complete with a hand-stitched brown bottier alligator leather strap and is water resistant to a depth of 30 metres.
