G. O. Guernsey’s patent escapement for watches
G. O. Guernsey’s patent escapement for watches. In this escapement two balance-wheels are employed, carried by the same driving-power, but oscillating in opposite directions, for the purpose of counteracting the effect of any sudden jar upon a watch or time-piece. The jar which would accelerate motion of one wheel would retard the motion of other. Anchor, A, is secured to lever, B, having an interior and exterior toothed segment at its end, each one of which gears with the pinion of balance-wheels.
Only the input is driven; every other part of this model moves by physics (MuJoCo), and its ratios are measured. Run it live, change its parameters, or switch the friction off to see the output stop.
- Modelled as
- Brown's face view, turned 60 degrees to his figure. A 30-tooth escape-wheel (the one driven joint, a constant torque from the mainspring) drives a dead-beat anchor A whose lever B carries, at its far end, two toothed segments: an exterior one (pitch radius 9) gearing with the pinion of one balance-wheel (pitch radius 1.5) and an interior one (pitch radius 7.2) gearing with the pinion of the other (pitch radius 1.2). Each balance has its hairspring (a joint spring). The anchor and the pinions are driven by tooth contact only, so the exterior mesh turns its balance against the anchor and the interior mesh turns its balance with it: the two balances always swing opposite ways.
- Measured
- The wheel steps half a tooth (0.1047 rad) per beat; the balances swing about 32 degrees with a period of 0.93 s; balance 1 follows the anchor at -6.0 and balance 2 at +5.85 (the shake in the teeth takes a little of the 6:1), and balance 2 follows balance 1 at -0.97; penetration stays under 0.1 mm.
- Notes
- The anchor's pallets are the dead-beat pallets of No. 289; Brown draws the segments as a single forked sector, here an exterior and an interior row of teeth on one arc; the balances' rims sit at two depths so that they can overlap as in the figure.
Film (MP4) · Still (PNG) · Spec (YAML) · Model (MJCF)
