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TRUBLUE Auto Belay

The TRUBLUE Auto Belay depends on eddy current magnetic braking to arrest a climbing fall.

The TRUBLUE Auto Belay is a self-regulating belay device designed to protect a climber without the need of a partner. Unlike traditional belay devices that depend on friction to provide a braking force, the TRUBLUE Auto Belay is unique because there are no parts in contact within the braking system! 

trublue auto belay  

Eddy Current

Eddy currents are electrical currents that flow in closed circular loops. They are induced when anon-magnetic metal is moved within a magnetic field.

It can go both ways!
Electric currents ↔ Magnetic Fields
Can Generate = ↔

Lenz's Law

Lenz's Law states that an eddy current creates a second magnetic field that opposes the magnetic field that created it.

How the TRUBLUE Works.

  • Webbing is wrapped around a spool within the device.
  • When a force (a falling climber) pulls the webbing out of the device, aluminum rotor arms connected to the spool begin to spin above the xed magnetic plates
  • The non-magnetic aluminum rotor arms moving within the xed magnetic eld generate eddy currents.
  • According to Lenz’s Law, the eddy currents create an opposing magnetic field.
  • This opposing magnetic field acts as a braking force to regulate the rate at which the webbing is released or in other words, how fast the climber falls.

Spool Spool of Trublue auto belay; looks like a rotor.

Rotary Arms Rotary arms of auto belay with center resembling a triangular shape.

Magnetic Plates

Magnetic plates of auto belay that is circular in shape and holds the spool and rotary arms in place.

Spool, Rotary Arm and Magnetic Plate put together

Auto belay with the spool, rotary arm and magnetic plate put together