By Gordon Henderson
Horology, at its core, is all about the pursuit of accuracy through mechanical timepieces. In that pursuit, the development of systems that eliminate any stimuli that detract from precision is paramount. In one of its newest feats, Arnold & Son has combined two complications that play as a horological version of Batman & Robin against the more nefarious elements of the accuracy underworld. We are referring, of course, to the effects of gravity and subsequent loss of accuracy when a watch is unable to maintain a consistent energy output.
As part of the Royal Collection Line, Arnold & Son’s Constant Force Tourbillon is a tour d’ force. As constant force watches have been garnering a lot of attention recently, it is essential to understand that “constant force” essentially offers consistently released power (from the mainspring) to a timepiece so that it does not run too fast at the beginning of its winding or too slowly at the end of the winding. (Depending on where the mainspring is in its power cycle, the power delivered can sometimes be more or less than required. Without a regulating body in place, this can lead to inaccuracy over time—much like trying to drive a car at a consistent speed while the power from the engine constantly changes.)
The constant force escapement maximizes power consistency. In Arnold & Son’s Constant Force Tourbillon – the mainspring and barrel has been reconfigured (and doubled) to offer the solution. Essentially, the brand started with the design of the mainspring — the foundation of power delivery for the watch. The new system incorporates two mainspring barrels that are built symmetrically and are visible on the dial at the 10 and the 1:00 positions. The first mainspring barrel is responsible for powering the gear train, while the second backs up the first whenever the power dips bellow an optimal level. The backup ensures that the power provided to the watch remains consistent.
While the constant force mechanism addresses accuracy-related issues that stem from the transfer of power, the tourbillon addresses the accuracy-stealing effects of gravity. To power the tourbillon in this watch, Arnold & Son has also gone to great lengths to ensure that power delivery doesn’t lead to inaccuracy. Via a patented constant force mechanism, the mainspring barrel does not directly power the Tourbillon. Instead the mainspring powers a small hairspring, which in turns delivers a consistent amount of power to the Tourbillon once each second. The constant force mechanism makes a full rotation once per minute and is meant to visually parallel the rotation of the 60-second tourbillon. The same device also powers a true-beat second hand, a feature that is a staple of Arnold & Son watches. What’s unique about the mechanism is that if the power reserve dips below the optimal level, the movement will completely stop vs. running at a lower level of precision. This full-on commitment to accuracy also offers a robust 90 hours of power reserve.
The layout of the anthracite dial is founded on symmetry. The symmetrical design of the complexities of this watch even extends to the screws, which feature beveled and mirror polished heads, and are arranged in a symmetrical pattern. The 46mm 18-karat rose gold watch is created in a limited edition of just 28 pieces on a hand-stitched patina brown bottier alligator strap. The watch retails for $197,500.