This is the recently designed Patek Philippe perpetual calendar with an original in-line display. The day, date and month appear in a large single aperture at 12 o'clock.
The design engineers at Patek developed a completely new self-winding movement 31-260 PS QL with an additional in-line display module, for which three patent applications have been filed. This highly sophisticated new caliber is housed in an elegant platinum case framing a vertical satin-finished blue dial with a black-gradient rim. The new movement not only delivers an original display, but it is also more legible and runs with greater reliability.
Patek Philippe has made perpetual calendar wristwatches dating back to 1925 but never in a straight-line format. Because of the mechanical complexity of this particular date arrangement, in-line calendar was reserved for extremely rare and one-of-a-kind pocket watches, such as the one numbered P-1450 from the 1970s that is now on display at the Patek Philippe Museum.
Putting an in-line perpetual calendar in a wristwatch is highly complex and requires many additional gears: Cal 31-260 which was developed for this watch with more than 500 moving parts. Patek uses a platinum microrotor in the new movement because the higher density of platinum over gold allows the automatic movement to wind more efficiently. To reduce friction and add efficiency the movement incorporates 55 jewels which is unprecedented for a calendar complication.
Ref 5236 is a blend of new and old: the case design harkens back to Ref 3448, which was Patek's first self-winding perpetual calendar, produced from 1962 to 1981. Compared to Ref 5140 and the vintage Ref 3448, Patek increased the case diameter from 37 mm to 41 mm for this model.
We are normally not a fan of large watches, but every millimeter of the larger case is functional: firstly, the dial has to be larger to accommodate the in-line date function with good legibility. Secondly, Patek used the extra room for a larger winding rotor and a more elaborate movement that is most pleasing to the eye. Compared to Cal 240Q seen in the previous references, there are now separate bridges and cocks for the escape wheel and balance wheel, which makes the machine look more intriguing.
This offering is factory complete and presents as an unworn watch. This package includes: Certificate of Origin dated 2021, Inner and Outer Boxes, Hang Tag, Spare Solid Back, Setting Stylus, and a Winding Box in Unused Perfect Condition.
Technical Data
Case Diameter: 41mm
Case Height: 11 mm
Movement: Cal 31-260 PS QL
Jewels: 55
Power Reserve: 48 hrs.
Frequency: 28,800
Hallmark: Patek Philippe Seal
