and thus we get the proper rate of speed for tappets five pick to the round.
Some loom makers use the wheel E as a change wheel. With a 24 wheel C and a 36 wheel E we get three picks to the round, thus—
| drivens | 90 × 36 | = 3 |
| drivers | 45 × 24 |
With a 24 wheel C, a 48 wheel E gives 4 picks,
With a 24 wheel C, a 60 wheel E gives 5 picks,
With a 24 wheel C, a 72 wheel E gives 6 picks.
Example.—Find the number of teeth for the wheel C on the bottom shaft to drive tappets seven picks to the round, wheel on tappets 63 teeth.
| 90 × 63 | = 18 wheel. Ans. |
| 45 × 7 |
Woodcroft’s tappets, as a rule, are driven directly from the crank-shaft. As these tappets are usually of a large circumference, a large wheel on them is of no disadvantage, although sometimes intermediate wheels are used.
If the tappets are twelve to the round, and the wheel on the tappets contains 192 teeth, a driving wheel of 16 teeth will be required on the crank-shaft.