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Caliber 9R86


Caliber 9R86

Spring Drive Caliber 9R86 may well be the world's most accurate spring-driven chronograph. It delivers a precision of ±15 seconds a month, or ±1 second a day and, equally importantly, measures elapsed time not to the nearest fraction of a second but exactly, thanks to the fact that the glide motion hands stop at the very instant that the button is pressed.
The 72 hour power reserve is maintained even if the chronograph is in operation.

Driving system Automatic with manual winding mechanism
Accuracy ±1 per day (±15 seconds per month)
Power reserve Approximately 72 hours
Jewels 50 jewels
Remarks Power reserve display function, Dual time function with 24-hour display, Stop watch、Quick correction function of time difference adjusting to a calender


Column wheel system for exact operation of the chronograph

A column wheel system is used to control the starting and stopping of the stopwatch. Its system ensures precise, error free control of the chronograph operation. The column wheel is designed to reduce stress on the clutch and lever, minimizing impact on the movement when the start/stop button is pushed.

The column wheel. The perfect start and stop mechanism
① When you press the START button, the end of the action lever rotates the pillar wheel to the right.
② The rotating column wheel causes the end of the start-stop lever on the pillar to fall between the pillars, causing two closed start-stop levers to open.
③ The clutch ring that is released by the two start-stop levers engages with a fourth gear wheel. (The fourth wheel is held against the clutch ring by the force of a spring.)
④ The second hand of the stopwatch starts to move.


A transmission system that ensures that the second hand does not jump when the START button is pressed

The vertical clutch system was created to prevent the second hand from jumping when the stopwatch START button is pressed. In the vertical clutch system, when the stopwatch START button is pressed, the start-stop lever opens, the fourth wheel and the clutch ring are engaged by the pushing force of the clutch spring, and the stopwatch begins to measure time.

The shuddering of the stopwatch that easily occurs with horizontal clutches is eliminated, and timekeeping is more accurate.


Greater accuracy

Achieving a level of stopwatch accuracy equivalent to the accuracy of the Spring Drive caliber itself would not have meant much if this accuracy were lost in the operation of the stopwatch. To minimize time measurement errors when the chronograph buttons are pressed, the operation of the buttons was made as precise as humanly possible. A two-step READY/START mode was adopted to ensure that the stopwatch operation would be error-free. It is the same mechanism as is used in Seiko’s hand held stopwatches for professional sports use. The chronograph enters READY mode when the push button is lightly pressed. A further press then starts the stopwatch.


Preventing operational error

The chronograph push-button uses a screw-lock mechanism. Turning the screw cover lowers a pipe inside, allowing the START button to be pressed. This newly developed mechanism prevents accidental operation of the button, resulting in more accurate time measurement.

What is the Spring Drive?

Spring Drive is a unique watch technology that combines the power derived from a mainspring with the high accuracy of an electronic watch. Like all other mechanical watches, Spring Drive uses the energy generated by the movement of the wearer’s wrist to move the hands, but it also uses this to create electrical energy that powers a unique regulator that is up to ten times more accurate than any traditional escapement.

The Tri-synchro regulator combines three types of power:

1. Mechanical power (to generate and store energy in a mainspring)
2. Electrical power (to activate an IC and quartz oscillator)
3. Magnetism (to apply a brake to the hands via a rotor/stator)

The combined operation of these three functions delivers one second a day precision and gives Spring Drive its unique signature, the elegant glide motion of the second hand as it moves around the dial, accurately, smoothly and silently.

Spring Drive combines the best elements of both mechanical and electronic watches. While three-hand versions have over 200 components, versions with more functions, such as the Spring Drive chronograph have well over 300, all of which are assembled by hand.