Draw
The reliability of the modern lever escapement depends upon draw; the pallets are angled so that the escape wheel must recoil a small amount during the unlocking. The draw holds the lever against the banking during the detached portion of the operating cycle. Draw angle is typically about 15 degrees to the radial.
Early lever escapements lacked draw (indeed some makers considered it injurious as a cause of extra friction in unlocking); as a result a jolt could result in the escapement unlocking.
Read more about this topic: Lever Escapement
Famous quotes containing the word draw:
“Some hours seem not to be occasion for any deed, but for resolves to draw breath in. We do not directly go about the execution of the purpose that thrills us, but shut our doors behind us and ramble with prepared mind, as if the half were already done. Our resolution is taking root or hold on the earth then, as seeds first send a shoot downward which is fed by their own albumen, ere they send one upward to the light.”
—Henry David Thoreau (1817–1862)
“And the shuttle never falters, but to draw an encouraging conclusion
From this would be considerable, too odd. Why not just
Breathe in with the courage of each day, recognizing yourself as one
Who must with difficulty get down from high places?”
—John Ashbery (b. 1927)
“There are some who speak well and write badly. For the place and the audience warm them, and draw from their minds more than they think of without that warmth.”
—Blaise Pascal (1623–1662)