The Origin of Today’s Automatic Chronographs

Vertical Clutch and Automatic Winding

Three automatic chronograph watches were released in 1969. Without a doubt, the one with the most lasting impact was the Seiko Caliber 6139. The combination of the compact automatic winding mechanism with a vertical clutch for more precise stopwatch measurement and a column wheel, which became widespread among high-end chronograph watches, is still favored by many watchmakers today.

No talk of 1969 would be complete without mentioning the Caliber 6139. This revolutionary movement had a fascinating background and a lasting influence.

61 5 Sports Speed-Timer: Released in May 1969 as the world’s first mass production automatic chronograph. Based on the 61 Series automatic winding movement, it was equipped with chronograph functions via a vertical clutch. The chronograph second hand took the place of a conventional second hand. In 1970, a 12-hour chronograph counter was added along with the Caliber 6138 movement. Automatic winding (Caliber 6139A). 21 jewels (later, 17-jewel versions were also made). 21,600 vibrations per hour. SS. Water resistant to 70 meters. (Seiko Museum collection)

 

An automatic chronograph was the dream of many watchmakers starting in the 1940s. Albert Piguet, the renowned watch designer for Lemania, had his doubts, however. “If you try to build an automatic chronograph, the case will end up being twice as thick,” he explained. The only way to raise the winding efficiency would be to make a large automatic winding mechanism. Building in a 12-hour counter and stop lever for the chronograph would also require a lot of space. Shrinking the automatic winding and chronograph mechanisms was essential to creating an automatic chronograph, but it was not until 1969 that this became possible.

Cal.6139: The Caliber 6139 movement added a vertical clutch and a 30-minute counter to the slim automatic winding Caliber 61 Series movement. The balance wheel was modified to a double-support assembly. The 61 Series, designed as a general-purpose automatic winding movement, was adopted in the Grand Seiko with extensive modifications and was intended to be manufactured later on automated lines. Outer diameter 27.4 mm, thickness 6.5 mm.

 

Removing the back cover reveals the Caliber 6139 movement with its automatic winding rotor. Ease of maintenance was a major feature of the 61 Series. The rotor could be removed simply by loosening the center screw. The two pushbuttons could also be removed together with the middle case.

 

Toshihiko Ohki, who had successfully created the hand-winding Crown Chronograph in 1964 at Suwa Seikosha (now Seiko Epson), was put in charge of developing the new chronograph. The automatic winding 61 Series he had designed on its base was adopted in the 61 5 Sports, which became a big hit. Buoyed by this success, Ohki at last set about designing an automatic chronograph.

At the time, Suwa Seikosha was making use of the Magic Lever, winding the mainspring with pawls as its automatic winding mechanism. The Magic Lever had the advantages of high winding efficiency, few parts and compactness, making it ideal for the automatic chronograph. However, it would need to be combined with a small chronograph mechanism.

Vertical clutch as viewed from an obliquely upper angle. This shows that, as of 1964, Seiko was forming even complex heart-shaped cams from stamped cutouts.

 

Once it was decided to base the design on the 61 Series movement with its center seconds train wheel, the adoption of a vertical clutch (friction wheel) was inevitable. This photo shows the vertical clutch placed on the fourth wheel. Visible at the top of the photo are the seconds chronograph wheel and the 30-minute counter wheel reset hammer. The barely visible protrusions on the top and bottom of the clutch are clamps for lifting the vertical clutch.

 

The automatic winding mechanism favored by Suwa Seikosha was the Magic Lever type, using pawls to wind the mainspring. Although the design had a large “dead angle (non-operation angle),” it used few parts, wound efficiently and, above all, was far more compact than the bidirectional automatic winding mechanisms of other makers. Caliber 6139 would likely not have come into existence without this automatic winding mechanism.

 

Nearly all mechanical chronographs branch the motive power to the chronograph mechanism by engaging a clutch at the fourth wheel, which rotates once per minute. Normally the fourth wheel is opposite the winding stem, and a horizontally sliding clutch is necessary for engaging with the centrally placed seconds chronograph wheel. In the case of the 61 Series automatic winding mechanism, however, which places the fourth wheel at the center, the horizontal clutch employed in conventional chronographs cannot be used. Ohki therefore chose to place the clutch that moves the chronograph directly on the fourth wheel. While his aim was uncertain, the vertical clutch, moving longitudinally, was clearly more compact than a horizontal clutch.

As Ohki recalled, “It was really a desperate situation. The problem was that there was no spring that would not bend in the direction of rotation (of the fourth wheel) and that would slacken on disengagement. So I came up with the idea of a special disk spring (for the vertical clutch).” In 1969, Suwa Seikosha completed Caliber 6139, an automatic chronograph movement with the Magic Lever and a vertical clutch. On May 21 of that year came the official release of the 61 5 Sports Speed-Timer. Judging by the release date, this was without doubt the world’s first mass-production automatic chronograph.

The Caliber 6139 movement became a landmark in the world of watches. In the mid-1980s, the 6139’s disk spring vertical clutch was adopted, with modifications, in the Caliber 1185 slim automatic chronograph of Swiss maker Frédéric Piguet. As this design was imitated by a succession of other firms, the Seiko vertical clutch became the global standard for automatic chronographs.

Stop, start and reset (from left to right). The layout of Caliber 8R48, with chronograph mechanism on the dial side, has ample room to spare. Furthermore, due to the compact vertical clutch, the “bending” of levers is kept to an absolute minimum, enabling stop levers to engage both 12-hour and 30-minute counters. The thickness, which is the disadvantage of a vertical clutch, is ingeniously minimized by having the vertical clutch engage the intermediate wheel of the offset seconds chronograph.

 

Continuing this tradition today are two automatic chronographs announced in 2019. Both the Seiko Automatic Chronograph 50th Anniversary Limited Edition and the Seiko Chronograph 55th Anniversary Limited Edition incorporate the automatic chronograph Caliber 8R48 movement made by Seiko Instruments. This movement mounts a chronograph module with vertical clutch on the dial side of the automatic winding 6R Series with Magic Lever.

Seiko Prospex Seiko Automatic Chronograph 50th Anniversary Limited Edition SRQ029 – An Automatic Chronograph 50th Anniversary Limited Edition based on the Caliber 6138 two-counter chronograph with 12-hour counter. Befitting a premium watch is the sapphire crystal, with a highly three-dimensional box shape. Automatic winding (Caliber 8R48). 34 jewels. 28,800 vibrations per hour. Power reserve approximately 45 hours. SS (diameter 41 mm, thickness 16 mm). Water resistance 10 bar. Limited edition of 1,000 watches worldwide. US$3,600. To be released December 7, 2019.

 

61 Chronograph: The design motif for the model “Prospex” is the so-called “Panda,” released in 1970. The narrow bezel design and thin hands and indexes led the way for 1970s design trends. Automatic winding (Caliber 6138B, movement diameter 27.4 mm, thickness 7.9 mm). 23 jewels. 21,600 vibrations per hour. (Seiko Museum collection)

 

Crown Chronograph: Seiko’s first wristwatch chronograph, released in 1964. It was designed by Toshihiko Ohki of Suwa Seikosha. He completed the work referring only to written materials. It was an orthodox design with a carrying-arm horizontal clutch and column wheel. Hand-winding (Caliber 5719A, movement diameter 27.6 mm, thickness 6.1 mm). 21 jewels. 18,000 vibrations per hour. SS. (Seiko Museum collection)

 

Seiko Presage Chronograph 55th Anniversary Limited Edition SRQ031: An homage to the Crown Chronograph. The basic structure is the same as the SRQ029. The Zaratsu polish is applied to the lug upper surface is also the same. As with the Crown Chronograph, however, it adopts a box-shaped crystal and the hair line finish on the dial are emphasized. Automatic winding (Caliber 8R48). 34 jewels. 28,800 vibrations per hour. Power reserve approximately 45 hours. SS (diameter 42.3 mm, thickness 15.3 mm). Water resistance 10 bar. Limited editions of 1,000 watches worldwide. US$3,300. To be released December 7, 2019

 

The reason Seiko adopted a vertical clutch in the first place was to reduce torque loss when starting and stopping the chronograph and prevent second hand jumping during chronograph operation, providing superior accuracy. It was this innovative thinking and technological wizardry that led to development of the world’s first mass-production automatic chronograph. Not to be forgotten is the additional advantage of the vertical clutch in that it enabled the chronograph mechanism to be made smaller than with a horizontal clutch.

Caliber 6139, combining a compact automatic winding mechanism and a vertical clutch, is the origin of today’s automatic chronographs. Without this movement, the history of the automatic chronograph would be completely different.

 

Timeline of Seiko Chronograph-Related Development

(D) means made by Daini Seikosha (current SII), and (E) by Suwa Seikosha (current Seiko Epson)

1941: Japan’s first pocket watch chronograph was developed and, adopted by the Japanese military as a type 1 luminous stopwatch (D)

1962: Aiming to become official timekeeper for the Tokyo Olympics, Seiko developed a new split-second stopwatch for athletic competitions (D) which won the approval of the Technical Committee of the IAAF in Belgrade, Yugoslavia (today’s Republic of Serbia)

1964: Served as the official timer for the Tokyo Olympics. The Seiko Crown Chronograph (Caliber 5719), incorporating a chronograph mechanism in the crown, went on sale in time for the Olympics (E). Following the Olympics, the Crown Chronograph Calendar (Caliber 5717), adding a date display to Caliber 5719, was released (E).

1968: The 61 5 Sports, aimed at the youth market, was a big hit (E)

1969: The 61 5 Sports Speed-Timer (Caliber 6139), with vertical clutch and column wheel, was developed as the world’s first mass-production automatic chronograph (E)

1970: The 61 Chronograph (Caliber 6138) appeared, adding a 12-hour counter to Caliber 6139, which previously had only a 30-minute counter (E). The 70 5 Sports Chronograph Week Data (Caliber 7017) was introduced as the world’s slimmest (at the time) automatic chronograph (D).

1971: The 70 5 Sports Speed-Timer (Caliber 7018)  added a 30-minute counter to Caliber 7017 (D)

1972: Served as the official timer for the Sapporo Winter Olympics. The 70 5 Sports Speed-Timer  (Caliber 7016) added 30-minute and 12-hour counters to Caliber 7017 (D).

1998: The Credor Power Reserve Chronograph (Caliber 6S74) was introduced as a hand-winding chronograph with power reserve display (SII)

1999: A limited-edition run of 25 watches of the Credor Chronograph skeleton model (Caliber 6S99) went on sale, celebrating 25 years of the Credor brand (SII). A second commemorative model, the Credor Pacifique Power Reserve Chronograph, saw a limited-edition release, it was based on Caliber 6S74 but used the automatic winding Caliber 6S77 (SII). The Credor Phoenix Chronograph was introduced with Caliber 6S78, eliminating the power reserve display of Caliber 6S77 (SII).

2000: The Credor Pacifique Power Reserve Chronograph 2000 (Caliber 6S77), equipped with a carbon fiber dial, was sold as a limited-edition release (SII)

2007: The first Grand Seiko chronograph appeared, incorporating the Spring Drive Caliber 9R8 Series and equipped with a chronograph mechanism combining a column wheel and vertical clutch (E)

2009: The automatic winding Caliber 8R28 incorporated a chronograph mechanism with a column wheel and vertical clutch on the dial side of Caliber 6R Series (SII)

 

More Information:

https://www.seikowatches.com/us-en/special/chronograph_historical/
https://www.seikowatches.com/us-en/products/prospex
https://www.seikowatches.com/us-en/products/presage