Constant Force Tourbillon

Reference: 1FCAR.B01A.C128R

Thanks for contacting us. We'll get back to you as soon as possible.


Limited Edition: 28 pieces
Case: 18-karat rose gold
Size: 46mm
Movement: hand-wound manufacture caliber A&S5119
Function: tourbillon, true beat seconds, constant force mechanism
Power Reserve: approximately 90 hours
Water Resistance: 30m
Dial: openworked
Caseback: sapphire crystal
Strap/Bracelet: hand-stitched alligator leather
Factory Warranty: two years


Its historical roots, aesthetic construction, and true-beat seconds ascribe the Arnold & Son Constant Force Tourbillon to the tradition of ultra-accurate marine chronometers.

A constant force involves inserting an energy-storage sub-system into the gear train just before the escapement. Supplied at regular intervals, this secondary reservoir produces extremely regular torque as it is released in consistent, small doses. It, therefore, differs from the barrels’ energy flow, which is delivered over a long period of time and naturally fluctuates. The balance spring thus receives an invariable source of energy, hence the name Constant Force.

The true-beat seconds is a consequence of this mechanism. As the constant force system is reloaded 60 times per minute, it is possible to display a second that jumps forward from marker to marker by simply attaching a hand to the winding wheel. Despite being a common feature of quartz watches, it remains a rare feat in mechanical timepieces.