Pendulum Brake

(Mechanical Overspeed Brake)

The pendulum brake is a purely mechanical safety device used in rescue boat and free-fall davit winch systems to prevent uncontrolled lowering caused by overspeed or drive failure. It operates independently of electrical or hydraulic power and provides automatic emergency braking.

Working Principle

The pendulum brake is driven directly by the winch drum or lowering shaft. During normal lowering, the rotational speed remains below the activation limit and the brake stays disengaged.

When the lowering speed exceeds the preset value:

Centrifugal force causes the pendulum weights to swing outward
The movement of the pendulum activates the brake mechanism
Friction linings engage with the brake drum or disc
The winch drum is smoothly decelerated and stopped

This ensures controlled stopping without shock loading on the wire rope or structure.

Main Components

Pendulum weights (centrifugal masses)
Brake shaft mechanically linked to the drum
Friction lining (asbestos-free, marine grade)
Brake drum or disc
Spring and linkage system for self-resetting
Speed adjustment mechanism (factory-set and sealed)

Key Features

Fully mechanical operation (no power required)
Automatic activation in overspeed conditions
Fail-safe design
Independent from service and holding brakes
Smooth braking to avoid dynamic load peaks

Design & Safety Requirements

Activation speed typically set to 1.3 – 1.5 times the nominal lowering speed
Capable of stopping 100% rated load plus safety margin
Designed to withstand repeated emergency operations
Tested under full load in accordance with class requirements

Advantages in Rescue Boat Applications

High reliability during blackout or system failure
Minimal maintenance
Proven solution for SOLAS-approved davit systems
Ensures compliance with LSA Code – overspeed protection requirements

Typical Applications

Rescue boat winches
Free-fall lifeboat winches
Gravity davits
Fast rescue boat davits