Breguet Ref: 7707/BA/13/286 In-line Perpetual Calendar Wristwatch

BREGUET : REF:7707BA/13/286

The House of Breguet presents the first wristwatch of its kind - an in-line perpetual calendar with instant change of year.

Faithful to the technical genius shown by its founder in the 18th century, the House of Breguet presented at Basel '97 a new men's watch fashioned in 18K gold, reference 7707BA/13/286. In its technical conception, this model is a salute to Abraham-Louis Breguet and the innovations this inventor brought to the world of horology two centuries ago.

This is the first wristwatch ever to feature an in-line perpetual calendar with instant change of year indication. This new movement allows all of the perpetual-calendar indications to be displayed on the same line on the dial in direct correspondence to the position of the various functions on the calendar plate.

This automatic 12-line caliber has 35 jewels, a straight-line lever escapement, a 22K gold oscillating weight and a ring-shaped monometallic balance wheel. The movement is visible through the transparent caseback. The model 7707 displays the day, date, month, year and leap year on a vertical line through the center of the silvered hand-guilloched gold dial. It is water-resistant to 30 meters.

The style of the 7707 is very classic and, despite the numerous functions, it gives a sense of refined elegance in keeping with the Breguet tradition. This wristwatch attests to the continuing spirit of the brand to perpetuate the heritage of its founder, a man who has given so much to the world of watchmaking.

BREGUET

HOW THE STRAIGHT-LINE PERPETUAL CALENDAR ACTUALLY WORKS

This calendar displays the days of the week, the date, the months and the leap-year cycle, as well as the hours and minutes. The specificity of this mechanism resides in the fact that all functions are arranged along a straight line and that it enables instantaneous year-change display.

• This model features two push-pieces. Pressing push-piece A advances all calendar displays by one day. Push-piece B enables individual correction of the days of the week. ........................................... .....................
• The hour wheel (1) meshes with the 24-hour wheel (2) to which the finger-piece (3) which moves the large lever (4) each day, is attached.. .
• Every 24 hours, the tip of the large lever moves the seven-pointed star-wheel bearing the days of the week disc.
• The 48-month feeler-spindle (5) which is part of the large lever (4) obtains indications on the duration of the respective months from the 48-month cam (6) which makes a complete revolution in four years, while the small pawl (7) attached to the lower part of the large lever moves the 31-toothed wheel (8) on a daily basis, bearing the date display.
• The overtaking cam (9) which is part of the 31-tooth wheel (8) moves the latter along by one, two or three days in the shorter months, by means of the large pawl (10) attached to the lower part of the large lever. ................
• The position of the large pawl (10) is determined by the profile of the 48-month cam (6), explored by the extremity of the 48-feeler-spindle (5).
• When the 48 feeler-spindle (5) falls into one of the notches of varying depths corresponding to months of 30, 29 or 28 days, the large pawl (10) makes contact with the catch of the overtaking cam (9), thereby moving the date display sharply forward to the first day of the following month. ..
• At this point, the finger-piece (11) which is part of the 31-day wheel (8) moves the month intermediate wheel (12) forward by one tooth, and this intermediate wheel in turn causes the 48-month wheel (13) fixed to the 48-month cam to move forward. .........................................................................
• The rotation of the 48-wheel (13) makes the year intermediate wheel (14) rotate, a movement which causes the month pinion (15) bearing the month display to rotate in its turn.
• We should now deal with the mechanism enabling the instant 4-year cycle display. The 4-year cam (16) is attached to the 48-month wheel and cam (6 & 13) and therefore completes a revolution every four years.
• The four-year lever (17) carries a feeler-spindle (18) which is maintained in permanent contact with the cam(16) by the lever release-spring (19). ..........................................................................
• The four-year pawl (20) is attached to the end of the lever (17) and is maintained in the correction position by its spring (21).
• The feeler-spindle (18) follows the curve of the cam (16) and at a given movement makes the four-year pawl (20) move by means of the lever onto the other side of the tooth on the four-year star-wheel (22).

On reaching the tip of the four-year cam, meaning December 31, the feeler-spindle unhooks and instantly drops down to recover its grip on the surface of the four-year cam. This movement is transmitted from the lever to the four-year pawl which immediately causes the four-year star (22) to move onward by a quarter turn.