Calibre CHR 29-535 PS. The acronym CHR stands for CHronographe à Rattrapante, the French term for split-seconds chronograph. What a stunning beautiful and fascinating timepiece!
When Patek Philippe presented its calibre CH 29-535 PS, a chronograph movement based on classic principles – manually wound, column wheel, horizontal clutch – in 2009 it was already clear that some day, it would be followed by an advanced version with a split second mechanism. That debut took place in 2012: Patek Philippe launched the Ref. 5204 split-seconds chronograph with a perpetual calendar. Now, for the first time, the Ref. 5370 incorporates the calibre CHR 29-535 PS in its pure form without the added complication of a perpetual calendar.
Because it is focused exclusively on time measurement, the Ref. 5370 has a decidedly masculine face.
With the Ref. 5370, the Geneva based family owned manufacturer also extended its range of pure split-seconds chronographs with a two-pusher model, a stopwatch with two pushers for the basic start, stop, reset functions and an additional on/off button in the crown for the split-seconds function.
The calibre CHR 29-535 PS movement is of course developed and crafted in-house by Patek Philippe.
These are its basic technical features:
- Clutch wheels with patented tooth profiles boost efficiency in power transmission and reduce wear.
- The mesh depth of the clutch wheels is not adjusted with an eccentric next to the clutch lever; this is done much more precisely and easily with an eccentric column wheel cap at the outermost end of the clutch lever.
- Self-adjusting hammers in jewel bearings simplify the servicing procedure.
- The brake lever that stops the chronograph wheel is directly synchronized with the clutch lever.
- The slotted minute-counter cam coasts the chronograph and split-seconds hands to a stop ratherthan abruptly blocking them.
And these new features of the mechanical chronograph are joined by innovations dedicated exclusively to the rattrapante function:
- When lap times are stopped, a newly designed isolator uncouples the split-seconds wheel from the chronograph wheel to eliminate unwanted friction and prevent a degradation of balance amplitude while the split-seconds hand is immobilized.
- The split-seconds lever that positions a ruby roller between two flat heart cam shoulders keeps the chronograph and split-seconds hands precisely aligned as long as they are superposed.
No doubt these mechanisms are not only ingeniously designed but also lavishly finished by hand. Most steel parts are painstakingly chamfered and their surfaces straight-grained; the split-seconds clamps are polished. The magnificent interplay of bright glossy and lustrous silky areas is enhanced with contrasting golden hues and sparkling red bearing jewels, showcasing watchmaking artistry that can be admired through the sapphire-crystal case back. This quality of finissage is expressly mandated by the Patek Philippe Seal. One of the watch industry’s strictest set of directives, as is the extremely high degree of accuracy that only tolerates deviations ranging between +2 and -3 seconds per day.
The CHR 29-535 PS calibre is housed in a 41 mm platinum case with an in-house manufactured enamel dial. It is made out of white gold with genuine black enamel and features applied Breguet numerals in 18 carat white gold, white printed scales, a railway-track minute scale, tachymeter scale calibrated to 1000 meters, subsidiary seconds at 9 o’clock and a 30-minute counter at 3 o’clock.
The Patek Philippe Ref. 5370 is sold for 215.150 Euro including 19 % VAT.
>>> See more stunning pictures of the Patek Philippe Ref. 5370 split-seconds chronograph on page 2 >>>