The escapement
The escapement of a wheel clock is used to let the escape wheel turn further at certain time intervals. Thereby the time is "chopped up" and can be counted. If the rotation is transmitted via cogwheels in such a way that the minute hand turns once an hour, people save themselves counting.
The form of the inhibition serves to transfer so much energy into the periodic oscillation that it neither stops nor continues to oscillate. The anchor escapement shown in the animation shows that the anchor supports the movement of the pendulum to the right as well as to the left.
Graphics: CC license
The more finely the time is divided and how well the energy flow from the drive is designed to maintain the vibration, the better the accuracy of a watch. There are numerous types of escapement for mechanical watches.
Waag (beam balance, spoon balance, Foliot)
The "Waag" in its various performances is the early (14th century), as yet unfinished form of the gait control. In the case of the beam balance, the beam with the spindle is attached to a thread. The period of oscillation can be regulated by moving weights. The deflection was often limited by pig bristles. Two metal plates are attached to the spindle and engage the escape wheel.
Spindle escapement
The scales were replaced by the pendulum in the middle of the 17th century (Christiaan Huygens). It has a much higher accuracy, so that a minute hand made sense.
The crown wheel set in rotation by the weight moves the spindle and pendulum in one direction until the second lobe stops the movement and reverses it.
In 1675 Christiaan Huygens used a spiral spring as a clock in a pocket watch (Zakhorloge). This transferred the precision of the pendulum to the portable clocks.
Graphics: CC license Wikipedia
Anchor escapement
The anchor escapement is a hook escapement that was invented by Robert Hooke in 1676. An anchor-shaped hook, which is fixedly connected to the pendulum on a shaft above the escape wheel, controls the release of the escape wheel and keeps the movement of the pendulum going by the pressure of the teeth of the wheel.
Their higher precision replaced the spindle escapement.
Drawing: CC license Wikipedia
Grasshopper escapement
The grasshopper escapement was developed by John Harrison between 1722 and 1737. He used them in his marine chronometers H1, H2 and H3, with which he solved the longitude problem.
Graphics: CC license Wikipedia
On the next page you will find a film that explains the function of the escapement in the H1.
Animation: Manfred Göllner
The scissor escapement
(Amant escapement, pin escapement, Mannhard escapement)
The scissor escapement was invented by the French watchmaker Louis Amant in 1741 and improved by Jean André Lepaute in 1753. From around 1800 it often replaced the spindle or anchor escapement of the Comtoise, as it achieved a higher rate of accuracy.
Next page: Film
