Brake disk 1 rotates about section 1 fixed axis C and has a wedge-shaped internal groove which is engaged by wedged braking shoe 3. Shoe 3 turns about fixed axis B. Disk 1 rotates freely counterclockwise. When it starts to rotate clockwise, it is braked by the jamming of the shoe in the groove of the disk. Shoe 3 is held in contact with the groove of disk 1 by flat spring 2.
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