File:VergeEscapementCycle.gif

English: Animation of a verge escapement, one of the ealiest types of clock escapements, creating a stepwise motion with a constant rotation angle per step. The escape wheel (green) is connected to clock's gear train and driven by a constant force. The verge (yellow) is connected to a foliot, a bar perpendicular to the axis of rotation with a high moment of inertia, and couples to the escape wheel via two pallets on its side. During a cycle, the escape wheel transfers momentum into the verge via one of the pallets, causing the verge to spin until the driven pallet looses contact with the wheel and the other pallet moves into the way of the teeth. As it is set to connect to the opposite side of the wheel, it moves towards the tooth, stopping it when they collide. The verge is then driven by the other pallet, causing it to spin in the other direction, moving the first pallet in the way of the teeth again, closing the cycle. Overall, the mechanism creates two discrete steps of half a tooth each during one period.

It should be noted that this is not an accurate representation of a verge escapement. The angle between the pallets in an actual verge escapement was 80° - 105°, not almost parallel as shown here. With the pallets placed as shown, both teeth would contact the pallets at the same time, jamming the escapement, and it would not turn.