Buffer Collision & Kinetic Energy

Calculate impact forces, required buffer stroke lengths, and kinetic energy dissipation for runaway cranes.

Read the Crane Buffer Sizing Guide
kg

For Long Travel, this is the total Crane Bridge + Trolley + Hoist mass.

m/min
mm

Check your buffer catalog for the allowable stroke (usually 60mm - 200mm for polyurethane).

Impact Results

--
Joules (Kinetic Energy)
Impact Speed -
Average Force -
Peak Buffer Force* -

*Peak force assumes a polyurethane buffer where peak force is approx 2x the average force. Hydraulic buffers will have lower peaks.

Why Calculate Buffer Forces?

When an EOT crane hits the end stops of the runway beam, the entire kinetic energy of the moving mass must be absorbed by the buffers. If the buffers are under-sized, they will "bottom out", transferring infinite force into the end carriage and runway structure, leading to catastrophic structural damage.

The Physics:

  • Kinetic Energy (E) = ½ × Mass × Velocity²
  • Work Done (W) = Average Force × Buffer Stroke Distance
  • Since all Kinetic Energy must be converted to Work (E = W), the Average Force = Kinetic Energy ÷ Buffer Stroke.

By increasing the buffer stroke (using a longer buffer), you significantly decrease the impact force on your crane's wheels and end carriages.