Small Avet Dog Mechanism

[mike1010]

More contact surface and the Avet "spring" grabs and pulls the actuator arm, the ABU is 100% friction.

Not sure I agree about the actuator arm.  It does not generate any force; that still comes all from friction.  The arm does direct that force to be effective, though.

The spring not the arm, the arm just transfers the force.

But it is still 100% friction, with the spring contributing to it just like the ears (which are springs) on the Ambassadeur dog.

[Keta]

Far more friction and the spring tightens around the hub as more force in put on it.

[mike1010]

Far more friction and the spring tightens around the hub as more force in put on it.

Sure, more friction, but I don't see the spring tightening around the hub.  When activated, the arm moves in against the hub, which may give the appearance of the spring tightening, but it isn't.

[Keta]

The "spring" is not really a spring,  it tightens on the hub as the hub turns.  The more turning the tighter it gets.  the ears on an ABU type AR are all friction.