Seiko ?Prospex?: 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.
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)
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.
Cal.6139: The Caliber 6139 movement added a vertical clutch and a 30-minute counter to the slim automatic winding Caliber 61 Seri...
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A Week in Watches Ep. 79 – Swiss Leftovers
29-04-2024 05:06 - (
Luxury Watch )