Lever resistance (or load). It is common to call the input force "the effort" and the output force "the load" or "the resistance." This allows the identification of three classes of levers by the relative locations of the fulcrum, the resistance and the effort: These cases are described by the mnemonic "fre 123" where the fulcrum is in the middle for the 1st class lever, the "r"esistance is in the middle for the 2nd class lever, and the effort is in the middle for the 3rd class lever. The lever is a movable bar that pivots on a fulcrum attached to
Lever escapement the exit pallet, which transfers a clockwise impulse to the balance wheel's impulse pin via the lever fork, while pushing the lever up against the left banking pin. The escape wheel drops again until the entrance tooth locks on the entrance pallet now being held in place by the left banking pin via the lever. The balance wheel continues clockwise, again free from interference until it is pulled back by the balance spring to the center position. The cycle then starts again. Each back and forth movement of the balance wheel from and back to its center position corresponds to