Lesson 1/Learning Event 1
Two shoes can be mounted so that selfenergizing action is effective
on both. This is done by pivoting the shoes to each other and
leaving the pivot free of the brake shield. The only physical effort
required is for operating the first or primary shoe. Both shoes then
apply more pressure to the braking surfaces without an increase in
pressure on the brake pedal. The anchor pins are fitted into slots
in the free ends of the brake shoes. This method of anchoring allows
the shoes to move and expand against the drum when the brakes are
applied. The selfenergizing action of the primary shoe is
transmitted through the pivot to the secondary shoe. Both shoes will
tend to turn with the drum and will be wedged against the drum by one
anchor pin. The other anchor pin will cause a similar action when
the wheel is turning in the opposite direction.
Another type of brake shoe that has been used consists of two links
anchored together on the brake shield with the end of each link
pivoted to one of the brake shoes. This allows more even application
of the braking surface because of the freedom of movement for the
brake shoes. Each shoe is selfenergizing in opposite directions.
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