A cylinder escapement
294 and 295. A cylinder escapement. 294 shows the cylinder in perspective, and 295 shows part of the escape-wheel on a large scale, and represents the different positions taken by cylinder, A, B, during an oscillation. The pallets, a, b, c, on the wheel rest alternately on the inside and outside of cylinder. To the top of cylinder is attached the balance-wheel. The wheel pallets are beveled so as to keep up the impulse of balance by sliding against the beveled edge of cylinder.
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
- This is No. 295's escapement, seen from above and to one side so the cylinder shows as a solid tube. The cylinder is the balance's axis, with the balance-wheel on its top. It is whole above and below, and at the level of the wheel's pallets a passage is cut away, leaving a little more than half of the tube (217°) between two lips. The escape-wheel's 15 wedges on their stalks pass through this passage. A wedge's point rests on the outside of the tube, goes in when the entry lip passes it and pushes that lip (the impulse), and rests on the inside. When the balance swings back, the point goes out under the exit lip with a second push, and the next point falls on the outside. The only input is a constant torque on the wheel (the mainspring). The balance is set going by hand: it is let go 2.2 rad from its rest.
- Measured
- The wheel goes 0.2094 rad per beat (half a tooth; 0.2094 expected) over 16 beats. The swing holds at 105°. The period is 1.040 s against the balance on its spring alone (1.034 s). The wheel never turns back more than 0.004 rad. The deepest contact is 0.32 mm.
- Notes
- Brown gives no sizes. The sizes are No. 295's. The whole parts of the tube above and below the passage are drawn but do not touch anything. The balance's mass is raised a little so that, with them, its inertia is the same as in No. 295.
Film (MP4) · Still (PNG) · Spec (YAML) · Model (MJCF)
