Zoom in for a closer look, then drag or swipe to move around the image.
Our 3D model viewed at an angle, in real time. Each tourbillon cage turns once a minute while its balance wheel swings back and forth beneath the graphite dial.
Open full-size image (opens in a new tab)Duet Dual Tourbillon
A closer look at two tourbillons.
Duet explores a mechanism we love: the tourbillon, a rotating cage that carries some of a mechanical watch’s timekeeping parts. We’ve modeled two beneath an open graphite dial, with gold-toned gears and a blue mechanism connecting them.
Wear OS 6 or later
Duet is a design study and isn’t available to buy. You can explore the model and its moving parts here.
Compatibility & installationTwo cages in motion
Each cage turns once a minute. Inside, a balance wheel swings back and forth, recreating the movement that sets the pace of a mechanical watch.
The blue connection
Between the cages is a differential: a set of gears that averages their two inputs. We use that relationship to animate the connected parts.
A view beneath the dial
The dial runs diagonally from ten to four, leaving the gears and both tourbillons visible beneath the hands.
How the two tourbillons work.
A tourbillon is a rotating cage containing a balance wheel, its spring, and an escapement. In a mechanical watch, the balance swings back and forth while the escapement releases the gears a little at a time. Duet recreates two of these assemblies, each turning once a minute.
The blue mechanism between them is a differential: a set of gears that averages the two inputs. It connects to the hour and minute hands and the small seconds dial above the right tourbillon. Both balance wheels swing at three full cycles per second, with their beats offset from each other.
Seeing the mechanism beneath the dial.
We’ve cut the graphite dial diagonally from ten to four and left the center open around the hands. That gives you a view of the gold-toned gears, silver supports, and blue connections beneath it.
Read the minutes from the longer central hand and the hour from the shorter one. The pale dial at the upper right shows seconds. In the dimmed always-on display, the hour and minute hands and a few markers remain visible on black.
Inside Duet
See how the gears connect, with tooth counts and ratios.
Following the gears
Each cage has its own gear train, or series of connected gears, driven from a barrel. A barrel holds the mainspring in a physical watch; here it is part of the modeled mechanism. Each train also connects to the differential through a 108-tooth wheel, a 100-tooth relay, and a 108-tooth input wheel. The matching input and output sizes preserve a one-to-one ratio.
Inside the differential, paired planet gears combine the inputs. These gears sit in a rotating frame called a carrier. The carrier turns at the average of the two input speeds and passes that motion to the gears that drive the hands.
The separate seconds hand uses two pairs of bevel gears, which transfer rotation between shafts at an angle. They pass motion through a horizontal shaft and back up to the seconds dial. Their 54:18 and 30:20 ratios give a combined 4.5-to-one speed increase.
| Assembly | Relationship | What you see |
|---|---|---|
| Twin tourbillons | One cage turn per minute | Two rotating cages, each carrying a balance and escapement. |
| Balances | 3 Hz / six beats per second | Balance wheels swinging back and forth with offset beats. |
| Differential | Average of two inputs | Blue carrier and paired planet gears between the tourbillons. |
| Central hands | Minute hand: one hour per turn; hour hand: twelve hours per turn | The minute and hour hands above the open center. |
| Small seconds | 54:18 × 30:20 = 4.5:1 | A separate seconds hand, driven through two bevel pairs. |
Duet is a digital design study. Your watch supplies the time, and our gear model determines how the parts animate. The gallery includes both the full 3D model and artwork arranged for the watch display. In exploded views, we separate the parts and enlarge the gaps to show how they fit together.
Before you install
Will it work on my watch?
This study is designed for the platform listed here. It isn’t available to buy.
- Platform
- Wear OS 6 or later
- Format
- Watch Face Format 4
- Availability
- Engineering study
- Product type
- Digital watch face