Drum Brake

Drum brakes

Double leading edge
The drawbacks of the single leading edge style of drum brake can be eliminated by adding a second return spring and turning thepivot point into a second actuator.

Now when the brakes are applied, the shoes are pressed outwards at two points.

So each brakepad now has one leading and one trailing edge.

Because there are two brake shoes, there are two brake pads, which means there
are two leading edges.

Hence the name double leading edge.