rom the time of its founding in 1839, the Patek Philippe manufacture has made its mark as a virtuoso of chiming watches, whether those that strike automatically “in passing” (grande sonnerie, petite sonnerie) or those that strike on demand (repeaters). In 1989, on the occasion of the manufacture’s 150th anniversary, Philippe Stern, then company director, launched the great revival of the wrist-worn minute repeater by announcing the famous self-winding caliber R 27, the first movement of its kind designed and built entirely in the manufacture’s own workshops. Since then, the minute repeaters have steadily regained a privileged place in Patek Philippe’s product range; indeed they now constitute the largest collection of minute- repeater wristwatches in regular production. No fewer than a dozen timepieces offer this Grand Complication, alone or combined with other functions (grande and petite sonnerie, tourbillon, perpetual calendar, chronograph, World Time etc.).

To celebrate Philippe Stern’s 85th birthday, Thierry Stern (of the fourth generation of the Stern family, appointed president in 2009) decided to honor his father by creating a special edition of 30 watches, endowed with a completely new movement developed solely for this piece and never to be used again. A watch identified as Reference 1938, for the year of the honorary president’s birth. The choice naturally went to a minute repeater, Philippe Stern’s favorite complication, combined with an exclusive acoustic function: an alarm chiming the programmed time. This complex mechanism was one of the five acoustic functions and one of the two patented world firsts unveiled in 2014 for the manufacture’s 175th anniversary on the Grandmaster Chime Reference 5175, the most complicated Patek Philippe wristwatch (20 complications), equipped with the manually wound caliber 300 “GS AL 36-750 QIS FUS IRM”.Joining the regular collection in 2016 as Reference 6300, the Patek Philippe Grandmaster Chime unites a grande sonnerie, a petite sonnerie, a minute repeater, a date repeater chiming the date on demand and an alarm chiming the programmed time.

Taking this alarm function chiming a programmed time and integrating it into the emblematic caliber R 27 proved a formidable task. For Patek Philippe’s engineers, development of the new caliber R AL 27 PS self-winding movement meant fundamentally rethinking the minute repeater mechanism in order to accommodate the alarm. The challenge was to create a watch in which the minute repeater and the alarm chime on the same two classic gongs while retaining the system of a slide piece set into the left flank of the case, a prized visual signature of the Patek Philippe minute repeaters. This required that upon actuation of the slide, the movement be capable either of instantly striking the time displayed on the dial (in minute-repeater mode) or of putting the strike on hold until the time displayed corresponds to the programmed time (in alarm mode). Contrary to classic minute repeaters, where winding by means of the slide instantly releases the striking-work, the addition of an alarm system made it necessary to be able to disengage the strike-work barrel from the strike train (the quarter rack, the minute rack, the hour beak).

All these technical constraints called for the addition of 235 parts, including a lever and column wheel for selection of the chiming mode and a fusee device with a strike-work detent mechanism that temporarily disconnects the power source (the strike-work barrel drum) from the striking mechanism–a system usually reserved for grande sonnerie watches. In developing caliber R AL 27 PS its designers filed four new patents for mechanisms making it possible, notably, to switch with complete safety from one chiming mode to the other; to delay the alarm strike until the right moment; to ensure, in every case, the correct strike sequence of “hours, quarters and minutes”; and to guarantee that the strike-work barrel is always fully armed with each actuation of the slide –so that the watch can always, if necessary, sound up to 31 strikes for the alarm (12:58). Furthermore, the strike-work barrel was fitted with a slip bridle to avoid any excessive tension in the spring.

Here, as in all Patek Philippe complicated watches, technical complexity is allied with great ease of operation – a design philosophy that puts the user’s needs first. The push-piece integrated into the crown serves to select the chiming mode, which is displayed in a small bell-shaped aperture at 3 o’clock. When the watch is in minute-repeater mode (black bell) the user can actuate the repeater slide at any time to hear the chimes of the hours, quarters and minutes elapsed since the last quarter. When the watch is in alarm mode (red bell) the slide must be actuated again to wind the alarm (the bell changes from red to white). When the alarm has been actuated but has not yet sounded (white bell) it is possible to return to minute-repeater mode by pressing on the push-piece without this releasing the strike.

The 12-hour programmable alarm time is set from one quarter-hour to the next by means of the crown pulled out to the middle position and the Breguet-style centre alarm hand in rose gold pointing to the scale in powdered rose gold on the periphery of the dial. To allow the maximum number of chimes to be heard, the alarm of Reference 1938P-001 always strikes two minutes before the programmed time. Accordingly, if the alarm has been set for 3 o’clock, instead of three low-pitched strikes (which could easily go unnoticed) the watch will sound two low-pitched strikes, three double high-low strikes and 13 high-pitched strikes, making 21 strikes in total. A true musical interlude. Safety systems prevent any damage in the event of incorrect manipulation –such as successive attempts to arm the slide when the alarm has already been actuated, or adjusting the movement time when the watch is striking.

The tribute to Philippe Stern continues on the 18K gold dial with its portrait in Grand Feu white and grey miniature painting on enamel, on a ground of Grand Feu black enamel. A tiny picture built up in small deft touches – fruit of one of the precious rare handcrafts that the manufacture’s honorary president has taken such care to nurture. Applied Breguet-style numerals and Breguet-style hour and minute hands, all in white gold, contrasting with the rose gold of the alarm hand and scale, lend their elegance to the time display.

The platinum case, hand polished throughout, is 41 mm in diameter. With its straight lugs and screwed-in strap bars, it too recalls one of the creations dear to Philippe Stern, dating from 1989, when, on the occasion of the manufacture’s 150th anniversary, he launched the limited edition Reference 3960 – a timepiece in the “Officer’s” style reminiscent of the earliest wristwatches, which emerged at the turn of the twentieth century. Platinum has been chosen as the most noble of metals, but also because it represents the greatest acoustic challenge for a minute repeater when the aim is to obtain the true “Patek Philippe sound” beloved of connoisseurs. Like all Patek Philippe watches in platinum, Reference 1938P-001 has a diamond set into the caseband at 6 o’clock. The case is also endowed with a sapphire crystal back protected by a hinged dust cover bearing the hand-engraved inscription “A mon père, 85 ans de passion horlogère” (To my father, 85 years of watchmaking passion). The sapphire crystal provides a fine view of the particularly painstaking finish lavished on the new R AL 27 PS self-winding movement. The chamfered edges of the bridges and hammers are gilded. The 22K yellow-gold mini-rotor is rhodium plated with yellow-gold edges and adorned with a black-lacquered hand engraving reproducing Philippe Stern’s signature. The touch of elegance and comfort extends to the alligator leather strap in shiny black with a platinum fold-over clasp.

Patents for caliber R AL 27 PS

• Unidirectional coupling mobile (European patent EP4058853A1)

This unidirectional coupling system was designed to form the connection between the rack and the strike-work barrel drum when the strike-work barrel spring is being wound (actuation of the slide piece). On the way out, the rack winds the strike-work barrel, whereas as it returns, it disconnects from the barrel –thereby preventing the strike-work barrel spring from unwinding.

• Timepiece incorporating a minute repeater and an alarm, with reversible selection by the user (European patent EP4071560)

This system enables the user to choose between a “minute repeater” mode, where the watch strikes the displayed time directly after actuation of the slide piece, and an “alarm” mode, where the release of the striking work, after actuation of the slide piece, is placed on hold until the time indicated by the movement corresponds to the programmed time. This selection can be changed at will and the mechanism is designed to be insensitive to errors of manipulation.

• Timepiece with repeater and constant-travel slide piece (European patent EP4071561)

• Striking mechanism equipped with a delaying device (European patent EP4071562)

This mechanism ensures that the slide piece for the striking-work always travels the same distance when actuated, regardless of the striking mode selected (minute repeater or alarm) and the number of strikes to be struck, with no risk of breakage. In this way, the user knows that the striking mechanism always has sufficient “wind” once the slide piece reaches the end of its travel.

This system for synchronising the racks in striking mechanisms consists of a blocking lever designed to delay the fall of the minute rack until the quarter jumper has moved towards the surprise-piece (a safety device that prevents miscounting just before a new hour begins). It ensures that the strikes always occur in the right order – hours, quarters and minutes – and therefore that the watch always chimes the correct time.

TECHNICAL SPECIFICATIONS

Reference 1938P-001
30-piece limited edition

Movement: Caliber R AL 27 PS Self-winding mechanical movement. Minute repeater and 12- hour alarm striking the programmed time on the same two classic gongs. Small seconds.

Diameter: 30 mm

Height: 8.23 mm

Number of parts: 561

Number of jewels: 47

Power reserve: Min. 43 hours – max. 48 hours

Winding rotor: Mini-rotor in rhodium-plated 22K yellow gold hand-engraved with Philippe Stern’s signature, unidirectional winding.

Frequency: 21 600 semi-oscillations per hour (3 Hz)

Balance: Gyromax®

Balance spring: Spiromax® (in Silinvar®)

Balance spring stud: Adjustable

Functions: 3-position crown:
• Pushed home: manual winding
• Pulled out to middle position: setting of the alarm time in 15- minute steps
• Pulled out all the way: setting the time

Pusher: Pusher for selection of chiming mode set into the crown at 3 o’clock

Slide piece: To actuate the minute repeater and the alarm. Set into the left flank of the case.

Displays: With hands:
• Hours and minutes from the centre
• Small seconds at 6 o’clock
• 12-hour alarm from the center

By a bell-shaped aperture at 3 o’clock:
• Indication of chiming mode: “minute-repeater” mode (black), “alarm mode” (red), alarm actuated (white).

Hallmark: Patek Philippe Seal

Case:
• Platinum
• Brilliant-cut diamond (0.02 ct) set between the lugs at 6 o’clock Sapphire-crystal back protected by a hinged dust cover
• Not water-resistant; protected against humidity and dust

Case dimensions:
• Diameter: 41 mm
• Width (from 3 to 9 o’clock with crown): 48.16 mm
• Length (across lugs): 49.4 mm
• Total height (crystal to dust cover): 14.2 mm
• Width between lugs: 21 mm

Dial:
• Dial plate in 18K gold with portrait of Philippe Stern in Grand Feu white and grey miniature painting on enamel, on a Grand Feu black enamel ground
• Applied Breguet-style numerals in 18K white gold
• Breguet-style hour and minute hands in 18K white gold Breguet-style hand for the alarm time in 18K rose gold Baton-style small-seconds hand in 18K white gold
• Railway-track minute scale transfer-printed in white; small seconds dial and Patek Philippe logo transfer-printed in grey Rose-gilt powdered quarter-hour scale for the alarm time

Strap: Alligator leather, large square scales, hand-stitched, shiny black, with platinum fold-over clasp.