DOCUMENTED BEFORE IMPLEMENTATION · 26 SEPTEMBER 2026
The mechanics
behind the model.
A teaching assembly based on documented principles. This is not a named caliber, a manufacturing drawing, or a physically validated movement.
Why the parts move this way
- Winding and running are different motions. The winding control turns the arbor. Once held, the arbor permits the spring to drive the barrel drum. The lid is removed in our cutaway. Horopedia: power source, sections 3–5 ↗
- The spring connects arbor and drum. The ribbon remains attached at both ends. Its changing shape is illustrative, not a calculation of spring stresses or constant blade length. Horopedia: mainspring ↗
- A wheel and its pinion share a shaft. Successive external meshes reverse direction and increase speed. Horopedia: counting and transmission ↗
- The escapement holds the whole train. Our wheel angles derive from the same release function, so every stage dwells together. Horopedia: Swiss lever escapement, sections 3 & 6 ↗
- The balance supplies the rhythm. The existing 4 Hz balance-and-spring illustration receives timed impulses in the teaching sequence. Horopedia: regulating organ ↗
From crown to spring
The crown and stem rotate together. In a real winding mechanism, a winding pinion and crown wheel transfer this rotation to the ratchet wheel on the barrel arbor. The click prevents reverse rotation. Our cutaway shows a schematic 12-leaf winding pinion, 24-tooth crown wheel and 48-tooth ratchet on the arbor. These are teaching counts. The crown wheel changes the rotation plane; the ratchet turns the arbor. Contrate face teeth are explanatory shapes, not validated contact profiles. Click geometry and the sliding/setting mechanism are omitted; anti-reversal is enforced by the model. Horopedia: winding mechanism ↗ · Crown wheel ↗ · Ratchet wheel ↗
Four visible crown turns represent one arbor turn in our chosen explanatory reduction. This ratio is not attributed to a real caliber. One activation fills the remaining demonstration charge; filling from empty takes fifteen seconds. On release, crown and arbor remain held while the barrel drum drives the train. In a real watch, winding can also occur while the watch runs; our lesson pauses the train to separate the two motions.
Calculated teaching ratios
These tooth counts are our chosen teaching set, not manufacturer specifications.
| Driver → driven pinion | Teeth / leaves | Ratio |
|---|---|---|
| Mainspring barrel → Center wheel | 96 / 12 | 8:1 |
| Center wheel → Third wheel | 80 / 10 | 8:1 |
| Third wheel → Fourth wheel | 75 / 10 | 7.5:1 |
| Fourth wheel → Escape wheel | 128 / 8 | 16:1 |
The 15-tooth escape wheel advances half a tooth per beat in this timing model. At eight beats per second, it averages 16 turns per minute. The chosen ratios give the fourth wheel one turn per minute, the center one per hour, and the barrel one per eight hours. These are arithmetic results for this assembly.
What the exhibit simplifies
- Gear counts, pitch spacing and signed angular ratios are calculated. Tooth profiles remain schematic; meshing contact, friction and backlash are not solved.
- The spring is a visual ribbon. Its torque, fatigue, thickness under contact, and conserved length are not simulated.
- The regulating organ reuses the first exhibition’s illustrative geometry. Draw, recoil, drop and safety action are not accurately modeled.
- The winding click acts as a constraint. The animated crown and stem show the winding input. The visible winding pinion and crown wheel transfer rotation to the ratchet above the barrel. Complete bearings, bridges, sliding pinion, setting parts and click geometry are omitted. The stem does not attach directly to the spring.
- The 90-second charge is a demonstration, not an actual power reserve.
- The 480× preview advances the train for inspection while holding demonstration charge. The balance, hairspring and fork move on a separate 1× display clock for visibility, while the train advances at 480×. This mixed-speed view does not represent synchronized tooth contact. Pause freezes both clocks; sound is suppressed. Selecting the balance returns to normal 1× playback.
Two layouts, the same train
The compact view folds the pathway around a circular plate. Each meshing pair keeps its calculated pitch distance, contact height and tooth phase. This is a teaching arrangement, not a reconstructed caliber or a manufacturing design. Rearranging it is a diagram transition, not a physical action a watch performs.
The Watch tabs use independent, labeled close-up clocks. They do not consume the main demonstration charge.
Verification standard
Automated checks cover each signed gear ratio, shaft speeds, locking, charge depletion, winding independence, spring attachments and pitch-center spacing. These checks support the stated teaching behavior; they do not replace inspection by a qualified watchmaker.
Horopedia’s English pages identify themselves as translations from French. We use the documented mechanical principles and avoid importing approximate efficiency claims or unsourced dimensions.