An industrial brake for application to an electrically-driven shaft in the event of power supply shut-down. The braking thrust is infinitely adjustable within a predetermined range by screw adjustment of the angle between a pair of levers pivoted to a brake control member at a single pivot. The remote ends of the levers are pivoted to respective arms carrying brake shoes for application to the shaft. A coiled spring tends to pull the brake "on" but an electrically-controlled thrustor normally overcomes the spring force except when its power supply is shut-down.