Inhibitor pendulum

Inhibitor pendulum (Galilean inhibitor pendulum).

The Hemmpendel (also Galilean inhibition pendulum , named after Galileo Galilei ) is a special case of the string pendulum for which, for small deflections, the oscillation period

${\displaystyle T=2\pi {\sqrt {\frac {l}{g}}}}$

where is the length of the pendulum and the acceleration due to gravity . ${\displaystyle l}$ ${\displaystyle g}$

With the inhibiting pendulum there is a pin at a distance vertically below the suspension point, against which the thread of the pendulum hits when the pendulum swings through the lowest point (the position of equilibrium), e.g. This creates a pendulum with the length on the left . Because of the law of conservation of energy, the pendulum swings just as high on the left as on the right. And when it swings back, its potential energy has been completely converted into kinetic energy when passing through the equilibrium position. So the pendulum continues to swing on the right side as if it hadn't been bent. The total period of oscillation then results from the sum of the halves of the two partial periods of oscillation: ${\displaystyle a}$ ${\displaystyle l-a}$ ${\displaystyle T}$

${\displaystyle T\,=\,{\frac {T_{1}}{2}}+{\frac {T_{2}}{2}}\,=\,{\frac {\pi }{\sqrt {g}}}\,\left({\sqrt {l}}+{\sqrt {l-a}}\right)}$

Conclusion: The pen inhibits spatial movement without consuming kinetic energy. The path, which is shorter on the blocked side, is traversed at the same translation speed in every height position as the more sweeping path on the uninhibited side and is therefore earlier at the upper reversal point, which shortens the period of oscillation. However, a rigid pendulum would break or buckle on a rigid obstacle. See. Determination of the notched impact strength with a pendulum with a material sample to be tested, which is deformed in the test.

The drawing shown has a locking pin that is lower than the reversal points (pendulum end positions). The pendulum therefore swings higher than the restraint pin on the restrained side. A swing back of the pendulum ball on the same path is therefore not possible. The ball will describe a loop around the left turning point, approach the commuting path from the inside and get back on it with a jerk. Part of the impulse and the energy are suddenly used up, so the right end position can no longer be reached. This jolt can be experienced when swinging as a person on a swing with two ropes, in real terms even before the end positions reach the height of the suspension, shortly after reaching the turning point.