Lever force F at a point "A" located by the coordinate vector r on the bar. The lever then exerts an output force F at the point "B" located by r. The rotation of the lever about the fulcrum "P" is defined by the rotation angle "θ" in radians. Let the coordinate vector of the point "P" that defines the fulcrum be r, and introduce the lengths which are the distances from the fulcrum to the input point "A" and to the output point "B", respectively. Now introduce the unit vectors e and e from the fulcrum to the point "A"
Lever escapement in alarm clocks, kitchen timers, mantel clocks and, until the late 1970s, cheap watches, called the "Roskopf", "pin-lever", or "pin-pallet escapement" after Georges Frederic Roskopf, who invented it in 1867. It functions similarly to the lever, except that the lever pallet jewels are replaced by vertical metal pins. In a lever escapement, the pallets have two angled faces, the locking face and the impulse face, which must be carefully adjusted to the correct angles. In the pin pallet escapement, these two faces are designed into the shape of the escape wheel teeth instead, eliminating complicated adjustments. The pins are located