Deep dive into natural and detent escapements of watches
The lever escapement is by no means the only arrangement for the regulating organs of the wristwatch. We look at just two largely historical forms here.
Sep 20, 2021 | By Luxuo Malaysia
This historical Breguet table clock exhibits all manner of clever mechanisms, including a constant force escapement and a detent escapement. In relatively immobile timekeepers, the detent escapement would have hit its stride. Image: Breguet
The story of the wristwatch escapement spins hard and fast, not always aiming for absolute precision. In presenting the basics of the beating heart of the mechanical calibre, we have only covered the basics. Considering that watch brands keep throwing research and development into this area, there will likely always be more to cover. No one expected the Zenith escapement when it was first announced, for example. Even in 2020, there is a new escapement in play, thanks to Seiko — but more on that specific development later. Believe it or not, there is more to cover in terms of escapement approaches already out there in the world.
In this story, we will be covering the natural escapement and the detent escapement. These two are somewhat related, which is why we opted to group them together. We will not be covering single-beat escapements overall, instead folding this type of regulating organ into the detent section. The reasons will become obvious once you get into the detent escapement, if you do not already know them.
As we previously noted in our coverage of the verge escapement, there were a few escapement ideas that preceded the Swiss lever, including a number that were in use before Christiaan Huygens pioneered the balance spring, ultimately perfecting it in 1675. We pause here for a moment to be clear that English scientist Robert Hooke (of Hooke’s Law) also has a claim to the balance spring but Huygens definitely had one built to his specifications.
While we pause to take stock, we also note that this story works best with an understanding of the basics of the escapement. A short summary is included here, for convenience.
The rest of this story is divided into a few parts, including the aforementioned sections on the two related escapements. We had planned to include a section on contemporary watches featuring these somewhat archaic and quite rare technologies, but it was not to be. It is a fact that these sorts of escapements are the rarest of all non-Swiss lever escapements out there.
As mentioned earlier, Grand Seiko is debuting an original escapement this year, but we will reserve that for our next story on escapement, when it can shine as the star of the show. To our knowledge, it is the only new type of escapement for 2020, a year that will definitely be the most unbalanced (so far) in the new millennium. It is important to note here that the new 9SA5 calibre features a dual-impulse escapement. So although it might remind some observers of variations on the detent escapement theme, it is most assuredly not that type of escapement.
A contemporary illustration of how the Earnshaw detent escapement works. Image: Cvetkovic, Stojicevic, Popkonstantinovic
We end this introduction with a note about pricing. Pioneering escapement technology is no easy matter, and the costs can be significant. Every press release about the development of such exotic regulators as the Girard-Perregaux Constant Escapement or the Zenith Oscillator implies tremendous research and development expense.
To illustrate this point, let us take a look at a specific example relevant to this story. The Urban Jurgensen 1140C, is an excellent case in point. This watch has a recommended retail price of EU48,100 in rose gold (excluding VAT). This contrasts with the 1140 RG Brown also in rose gold, which goes for EU28,200 (excluding VAT); this version has a regular Swiss lever escapement.
While there is no way to know if the difference in prices is down to the movement, you can certainly expect to pay a premium for special escapements. They are certainly worth more, being far from vanilla, but how much more depends on where you stand on the value such developments add.
Détente: the most reliable mechanical systems for watches