Patek Philippe World Time Geneva Harbor 7131 (7131/175R-001)

GMT XXL - Summer 2009

After devoting its cover page and its special report to the Aquanaut in 2007 and to the Gondolo in 2008, this year's Swiss edition of GMT XXL is focusing on Patek Philippe chronographs: from the thinnest in the world (following page) to the most iconic, unveiling the engraved brand-new Patek Philippe Seal (see box).

After it was launched in January 2006, the Annual Calendar Chronograph Ref. 5960 in platinum instantly became a bestseller among Patek Philippe's complications. With its patented Annual Calendar and Patek Philippe's proprietary self-winding chronograph movement, it offers functions that are very useful in everyday situations. Now, this technical opus also comes in a case made of 18K rose gold and is engraved with the Patek Philippe Seal. Developed and manufactured in-house, the self-winding chronograph caliber addressed an expectation long harbored by many aficionados and collectors of Patek Philippe timepieces.

In addition to the normal time indication, the movement stands out with numerous features. It has a flyback column-wheel chronograph, a power-reserve indicator, an annual calendar with day, date, and month, and a day/night indicator. The winding power is generated by a unidirectional central rotor in solid 21K gold. With its classic column wheel and a vertical disk clutch, the movement combines the traditional chronograph control concept with a modern power transmission solution. It offers high functional reliability and eliminates the danger of hand bounce when the chronograph is activated. Because of its low-wear design and the absence of any negative influence on the rate accuracy of the watch, the chronograph hand can be used as a continuously running seconds hand without hesitation.

The patented Patek Philippe Annual Calendar is a full-function calendar that automatically recognizes months with 30 and 31 days and when kept running only needs to be corrected by hand once a year on March 1. It displays the day, date, and month in three apertures and controls the day/night indicator at 6 o'clock. On three concentric scales, it indicates elapsed minutes and hours while the chronograph is running. On the two outer scales, the longer red hand counts the minutes from 0 to 30 (red numerals) and from 30 to 60 (blue numerals), while the shorter blue hand keeps track of as many as 12 elapsed hours along the innermost scale. The day/night (am/pm) indication is a small round aperture that progressively changes its color from white (day) to dark blue (night) and vice-versa.

PERPETUAL CALENDAR CHRONOGRAPH REF. 5970

An iconic Patek Philippe complication since the 1930s and 1940s, the famous Perpetual Calendar Chronograph pursues its majestic evolution with the serenity of a multiple record-holder in sales orchestrated by the finest auctioneers. Presented in rose and white gold versions with a new 40 mm diameter at the 2004 Basel Show and in yellow gold in 2008, reference 5970 with its distinctive lugs appears this year in a platinum version, with an ebony-black dial. The broad bezel opening leaves even more room for the dial which now comes in black, thus providing space for a 1000-based tachometric scale arranged around the minute track, yet without reducing the clear read-off of the hours and the perpetual calendar indications.

WORLD THINNEST SPLIT-SECONDS CHRONOGRAPH REF. 5959

With the world-first presentation of the thinnest ever split-seconds columnwheel chronograph in 2005, Patek Philippe reaffirmed its supreme mastery of complications. Despite measuring just 5.25 mm thick, Caliber CH R 27-525 PS is endowed with all the signature features of traditional fine watchmaking. It is housed in a magnificent platinum case designed in the classic Officer watch style and measuring just 8.5 mm thick. This feat is due in particular to the distinctive construction of the minute counter which moves continuously forward instead of jumping after each complete minute, as is generally the case. The minute counter is driven by an intermediate wheel (a small toothed wheel that is part of the time-setting mechanism), which meshes with the cannon-pinion. This intermediate wheel has the same number of teeth as the cannon-pinion, which performs one revolution per hour; it therefore turns at the same speed, which makes it possible to feature a 60-minute dragging counter on the dial. The shaft of the minute counter crosses through the entire movement right through to the chronograph mechanism on the bridge side.

PATENTED TEETH PROFILE

Another exclusive feature of this movement is the fact that the chronograph mechanism wheels are fitted with patented tooth profiles. To transmit the energy from the fourth wheel to the chronograph wheel via an intermediate wheel, the normal solution is to use three finely toothed wheels with a triangular tooth profile. This profile is designed to reduce "clearance" or the play between the teeth. To avoid any shake of the chronograph hand, its driving wheel is slightly slowed down by means of a friction spring. The new tooth profile of the above-mentioned three wheels serves to guarantee optimally smooth operation of the chronograph.