De Bethune Innovations: The Triple Pare-Chute Antishock System
How De Bethune makes a star out of an unsung hero of watchmaking.
The antishock system is something most watch enthusiasts can go a lifetime without thinking about even once, but without it, modern wristwatches couldn’t exist (or at the very least, they’d be in for a service a lot more often). The purpose of an antishock system is to prevent damage to the steel pivots of the balance in case of an impact to the watch. The two balance pivots run in jeweled bearings and the pivots themselves are very thin, in order to reduce friction to a minimum. This however means that the pivots are rather fragile, which is a situation exacerbated by the mass of the balance itself. Especially in pocket watches, which generally have balances significantly heavier than those in modern wristwatches, even a relatively small shock can bend the balance staff or actually break it.
In order to address this problem, Breguet (who else) invented his “pare-chute” antishock system. The word means “to protect from falls” and was originally coined in the late 1700s to describe what today we still call the parachute – a device intended to allow for a controlled descent from a balloon (and of course later, an aircraft). The Breguet pare-chute had a couple of different purposes. One was of course to protect the balance pivots from impact. Breguet, according to George Daniels’ comprehensive The Art Of Breguet, originally came up with the idea because he was concerned about the jolting caused by the oscillations of the platinum winding weight in his perpetuelle (self-winding) watches.
The other consideration was to equalize the pressure on the balance pivots in the flat and vertical positions. Antishock mechanisms consist of a bushing that holds a jewel with a tiny hole in it for the balance pivot, on top of which sits a cap jewel held in place by a small, flat spring. The tip of the pivot is held against the cap jewel by the pressure of the two springs above and below the pivots, essentially floating in place. This tends to minimize the difference in rate between the horizontal and vertical positions – which is also what the tourbillon is supposed to do – and the system allows the balance pivots to be displaced slightly, both vertically and laterally, in the event of a shock, which helps to dissipate the energy of the impact.
The evolutionary pressure necessary for the next step in the evolution in antishock systems occurred with the advent of the wristwatch, which was much more exposed to hazards than the pocket watch. Even with a lighter balance, there was no getting around the fact that some sort of protection for the balance was necessary, and in 1929 Swiss watchmaker Fritz Marti patented what would later become known as the Incabloc antishock system.
The Incabloc system has subsequently been joined by dozens of other antishock mechanisms and although today the variety has dwindled somewhat, there are still a plethora of them. All of them are basically constructed around the same principle – a combination of pivot jewels and cap jewels, in a mobile mount, held in place by antishock springs. De Bethune’s Denis Flageollet, however, has come up with something extremely rare in modern watchmaking: a real innovation to the antishock mechanism, which is De Bethune’s Triple Pare-Chute system.
The triple pare-chute system consists of several distinct components. First, there is a conventional Incabloc style antishock system on the upper and lower balance pivots, which consists for both pivots of a bearing jewel and cap jewel, held in place by the antishock spring (the spring is hinged, so you can’t lose it, which given its minute size is a big plus). The upper pivot is in turn held in place by an elongated bridge, with cut-outs in it to increase its flexibility. At the end of each side of the bridge are two additional jewels which are held in place by additional anti-shock springs, which act as additional buffers against shock.
There are therefore three major anti-shock protection points – the Incabloc system, plus the two additional anti-shock springs and jewels.
The system exists in several different versions but all share the same basic architecture and basic principles. The triple pare-chute system is designed to provide an additional layer of shock protection but it is also designed to more rapidly re-center the balance in the event of a significant shock to the watch. This is an improvement not only in basic protection of the most delicate part of any mechanical watch – the balance pivots – but also an improvement to chronometry in general.
The logic behind the triple pare-chute system is convincing but of course, as with the De Bethune balances they are also very aesthetically compelling. This is one of the most absorbing things about De Bethune in particular and fine watchmaking in general. High quality watchmaking, from Breguet to De Bethune, lives or dies by the degree to which it is successful at achieving its technical goals. However, there need not be a dichotomy between achieving technical goals and creating something beautiful; indeed, I don’t think that the distinction would ever have occurred to Breguet nor do I think it really occurs to Denis Flageollet either. Breguet did not invent the pare-chute system just to have something pretty to put on top of the balance cock, but his system is very beautiful because in executing it he was exercising his innate good taste and applying high standards of craftsmanship. The same is true of the triple pare-chute system – it is effective functionally, and derives its natural beauty from the fact that it represents an ingenious technical solution taken to its logical conclusion.
For Part 1 of this series, see De Bethune Innovations: The Science Behind The De Bethune Balances.