The ornate, double-dialed Grandmaster Chime dominated coverage of Patek Philippe’s 175th anniversary, which the brand marked last year. It is an amazing timepiece that makes a big statement. The watch we look at today is its counterpoint. With one dial and two hands, it appears to be the paradigm of simplicity, but it’s not.
The Patek Philippe Chiming Jump Hour is one of the timepieces Patek Philippe created to celebrate its 175th anniversary. Bearing Reference 5275P-001, it will be produced in a limited edition of 175 pieces, priced at SFr. 310,000. As the name indicates, this watch offers a jumping hour display with minutes and small seconds, and it strikes a single chime at the top of each hour. Let’s take a look at why this watch is much more than meets the eye.
1. Complexity and Rarity
The old adage about not judging a book by its cover was written for the Chiming Jump Hour. If you don’t think a watch that looks this simple can be complex, consider this number: 438. That’s how many parts there are in the movement. Remember, this watch displays hours, minutes, and seconds, and it strikes a single chime at the top of each hour. That’s it. Compare the parts count with (apparently) much more complicated Patek Philippe Caliber R TO 27 PS found in the Ref. 5539. That movement offers central hours and minutes, small seconds, a minute repeater and a tourbillon, and it contains 336 parts – 102 fewer than the Chiming Jump Hour. That gives you a sense of the 5275P’s hidden complexity. As we’ll discuss below, most of the complexity is due to the fact that all three time displays are of the jumping variety – a so-called “triple-jump” timepiece.
Now consider that this entirely new, highly complex movement, that took four years to develop and that has four patents, will be used exclusively in the Chiming Jump Hour, which is a limited edition of 175 pieces. That so much effort would be invested in a movement that will appear only once, in a limited-edition timepiece, is remarkable.
2. Energy Management
Striking and jumping complications are power-hungry, and this watch has four of them. Most repeating watches employ a second mainspring to power the strikes. Most jumping displays employ separate springs to store and release energy. Yet the Chiming Jump Hour has only a one mainspring, and a small spring for the jumping seconds. The chime, the jumping hours (displayed on a heavy disk), and jumping minutes are all powered by the lone mainspring, yet the power reserve is a healthy 48 hours.
Patek accomplished this with a combination of new and patented mechanisms, and with modern materials. Specifically, the lever and the wolf-tooth wheel in the jumping seconds system are made from Silinvar, Patek’s version of silicon. The material is extremely light and almost friction free, so it saps very little energy. We’ll discuss the springless-jumping displays in the next section. Patek’s achievement is such that even with a single mainspring, the Chiming Jump Hour offers a 48-hour power reserve. This is especially remarkable when you consider that at the top of each hour, the chime strikes while the hours, minutes and seconds jump simultaneously.
When the hands on a traditional watch circle the dial, you don’t even think about whether they all cross 12 at precisely the same moment. However when hands jump instantly, the eye will catch even a tiny discrepancy in the motion. To make sure the Chiming Jump Hour’s hands jump at precisely the same moment, Patek had to devise a new mechanism, and it is protected by another patent.
Patek says that the mechanisms it devised not only store the energy required to make the jumps, but they also synchronize the jumps. The fourth wheel (seconds hand) carries a snail cam that allows a ruby pallet to drop over the cam’s peak after each full revolution. Via a lever, this briefly releases the center wheel (minutes hand), allowing it to turn clockwise by six degrees concurrently with the fourth wheel. The center and fourth wheels advance at the same moment, so the seconds and minutes hands jump simultaneously.
This article was originally published on November 23, 2014, and has been updated.