A practical course in horology by Kelly Harold Caleb

Author:Kelly, Harold Caleb
Language: eng
Format: epub, pdf
Tags: Clocks and watches
Publisher: Peoria, Ill., The Manual arts press
Published: 1944-01-24T04:00:00+00:00

Usually, moving one pallet is all that is necessary. The question may arise as to which pallet to move. This would depend largely on the condition of the draw, the drop locks, and the angular motion of the lever from the line of centers, for we shall soon learn that whenever a pallet is shifted for any reason all of the above conditions are altered.

SHAKE Shake is defined as that space separating the letting-ofif corner of the pallet from the heel of a tooth when the opposite pallet is locked at the lowest locking corner. Shake is similar to drop except that the examination for shake occurs at the time when the tooth is locked at the lowest locking corner of the pallet. When moving the lever away from its bank but not enough to unlock the escapement, it will be observed that a slight recoil of the escape wheel has taken place. This action lessens the space between the letting-off corner of the pallet and the heel of the tooth, showing that shake is always less than drop. If an escapement has no shake the watch will stop.

THE LIFT Modern escapements have a total lift of 83^ degrees. The amount of lift separately on tooth and pallet is designed in varying proportions in different makes of watches. The lift in a club-tooth escapement is a very complicated action and requires considerable study to understand it. It will be noticed that the lift does not function exactly the same on both pallets. On the receiving pallet the wheel moves up as also does the pallet and the pallet's locking corner moves with greater velocity than the letting-off comer. On the discharging pallet the condition is reversed and the wheel moves

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