Patek Philippe ultra-thin self-winding perpetual calendar


Ultra-thin self-winding perpetual calendar

A great classic reasserts its tradition
La Cote des Montres - December 28th, 2012

The ultra-thin self-winding Perpetual Calendar has ranked among Patek Philippe’s most popular complicated watches for many years. Now, the workshops are relaunching it in a format that emphasizes the brand’s heritage in perpetual calendars: the Ref. 5940 in an 18K-gold cushion-shaped case.

In the category of grand complications, which includes tourbillons, minute repeaters, or split-seconds chronographs, the perpetual calendar unquestionably offers the greatest everyday utility because it always indicates the correct date by taking into account the different durations of the months. Perpetual calendars were coveted complications in Patek Philippe pocket watches dating back to the 19th century. And when wristwatches became fashionable, the manufacture in Geneva was the first to miniaturize the ingenious calendar mechanism to such a degree that it would fit in cases for the wrist, which incidentally were much smaller then than they are today.

It was 1925 when Patek Philippe presented the world’s first wristwatch with a perpetual calendar. Watch No. 97’975 displayed the hours and the minutes from the center, the seconds in a subdial at 9 o’clock, and the moon phases at 3 o’clock. Its analog calendar indicated the date with a hand from the center, the day of the week at 12 o’clock, and the month at 6 o’clock, taking into account leap years but without actually displaying the 4-year cycle as is customary today. The calendar functions were implemented as instantaneously jumping displays – a particularly challenging degree of difficulty.


Ref. 5940. Ultra-thin perpetual calendar in a form case


Around this time, the Art Deco movement established itself in Europe. With its clear and creative style elements, it influenced the fine arts and architecture, furniture, and product design in a distinctive way that has lost none of its persuasive eloquence. Patek Philippe embraced the style as well. Not as a short-lived trend, however, but as a sustainable design philosophy that continues to manifest itself in the Gondolo collection. The class of so-called form watches includes all timepieces whose cases are not round. Form watches can be square, rectangular, or triangular as well as rhombus-, tonneau- and cushion-shaped. The still young and readily visible wristwatch soon acquired the status of a design accessoire and remains very much en vogue to this very day. At Patek Philippe, cushion-shaped watches were highly popular, and some models can now be admired in the showcases of the Patek Philippe Museum. Alongside the round Calatrava classics, the unique Golden Ellipse, and the inimitable, casually elegant Nautilus, they are envoys of Patek Philippe’s timelessly beautiful design language.

The cushion-shaped case experienced a first renaissance in 2010 with the ultra-thin split-seconds monopusher chronograph Ref. 5950 in stainless steel, and now, it stands in the limelight again with the new ultra-thin perpetual calendar Ref. 5940. With a length of 44.6 mm and a width of 37 mm, it features a very contemporary format with strong masculine appeal due to its modest height of merely 8.6 mm. In the high-tonnage presses at Patek Philippe’s workshops, the slender silhouette is literally wrought out of 18K-gold blanks with the traditional cold-forming technique, followed by numerous consecutive machining steps. Finally, long hours of manual work are invested in polishing each case to a mirror gloss. It has gracefully curved flanks that appear to melt into the seamlessly integrated strap lugs. The watch is delivered with a sapphire-crystal snap back, which allows the owner to observe the consummately finished movement at work, and with an interchangeable snap back in solid yellow gold.


Caliber 240 Q:

A legend for eternity  

The caliber 240 Q movement is a masterpiece of technology crafted in its entirety in the manufacture’s ateliers for complicated watches. Composed of 275 individual parts, it is only 3.88 high, despite the fact that it is self-winding. The basic movement launched in 1977, with a 22K-gold off-center mini-rotor recessed in the plate, already accounts for 2.53 mm. So merely 1.35 mm remain for the mechanical memory that spans an entire 4-year cycle and at the same time emulates the lunar orbit. The perpetual calendar always indicates the correct date, automatically taking into consideration the months with 31, 30, or 28 days, and the 29th of February in leap years. It does not need to be corrected until 2100, a secular year that omits the leap day pursuant to the rules of the Gregorian calendar. But this adjustment can be made quickly and easily, and thereafter, the watch will continue to display the correct date for the next 100 years, provided it remains wound without interruption. The moon-phase display is similarly accurate: it deviates from the true position of the moon by one day every 122 years, which is equivalent to a daily error of 0.002. And finally, the rate accuracy of the movement – responsible for timekeeping precision – is impressive as well. It ranges from -3 to +2 seconds per day as stipulated by the directives of the Patek Philippe Seal for all mechanical movements with diameters of over 20 mm. This beats the values required for officially certified chronometers.


A timelessly elegant face


This stunning rate accuracy is celebrated on a dial that deserves the attribute timelessly elegant in every respect. It has a grained, cream-colored surface that perfectly matches the gold hue of the case and is framed by a black transfer-printed railway-track minute scale that faithfully follows the contours of the bezel. Applied Breguet numerals as well as slender, leaf-shaped hands in gold indicate the time, accompanied by three subsidiary dials for the calendar displays. At 9 o’clock: the day of the week and the 24-hour dial. At 3 o’clock: the month and leap-year cycle. At 6 o’clock: the analog date and the moon phases. All indications are well organized and crisply legible, as is customary at Patek Philippe.

With its new Ref. 5940, Patek Philippe opens up a new chapter in perpetual calendars with the revival of the cushion-shaped case that looks as topical today as the 1920s and 1930s Art Deco showpieces in the Patek Philippe Museum that inspired it. The stately timepiece is worn on a matt black hand-stitched alligator strap with square scales and a prong buckle in 18K yellow gold.

Patek Philippe ultra-thin self-winding perpetual calendar

Men’s wristwatch with perpetual calendar in 18K yellow gold Reference 5940

Movement:Caliber 240 Q
Ultra-thin self-winding mechanical movement.
Perpetual calendar with analog displays for the date, day of the week, month, and leap-year cycle.
Moon phases.
Diameter:27.50 mm
Height:3.88 mm
Number of parts:275
Number of jewels:27
Power reserve:48 hours
Winding rotor:Recessed 22K gold minirotor, unidirectional winding
Frequency:21,600 semi-oscillations per hour (3 Hz)
Balance spring:Spiromax®
Functions:Two-position crown
– Pushed in: to wind the watch
– Pulled out: to set the time
Displays:Center hour and minute hands
Subsidiary dials:Day of week and 24-hour dial at 9 o'clock
Month and leap-year cycle at 3 o'clock
Date and moon phases at 6 o'clock
Correctors:At 9 o'clock: day of week correction
Between 11 and 12 o'clock: date correction
Between 12 and 1 o'clock: month correction
At 6 o'clock: moon-phase correction
Setting stylus in ebony and 18K yellow gold delivered with the watch.
Hallmark:Patek Philippe Seal
Case:Cushion-shaped case in 18K yellow gold, cambered sapphire glass.
Back:Sapphire-crystal snap back and interchangeable solid snap back in 18K yellow gold.
Water-resistant :30 meters
Case dimensions:Length x width 44.60 x 37.00 mm
Height:9.25 mm (overall)
Height:8.5 mm (back to glass)
Width between lugs:21 mm
Dial:Cream-colored, grained
Nine applied Breguet numerals in 18K yellow gold.
Leaf-shaped hour and minute hands in 18K yellow gold.
Day of week, month, and date hands in 18K yellow gold.
24-hour and leap-year-cycle hands in blued steel.
Strap:Alligator leather with square scales, hand-stitched, matt black, prong buckle in 18K yellow gold.