| 摘要 |
A combined safety clutch and brake mechanism for a rotary lawn mower blade has a driven blade carrier with self-energizing centrifugal shoes biased to engagement with a driving drum. Brake drum segments fixed to the shoes are engaged by a brake band which physically forces the shoes to declutched position. To ensure reliable operation, the brake band is connected to a lever arm which is strongly biased to brake-ON position by a coil spring engaged about a guide rod and disposed along the movable end portion of the brake band, in a chordal position between the band and a surrounding protective bowl. The geometry of the lever arm and spring thrust line progressively reduces the force required to actuate the brake band to OFF position, relative to the spring force, as the lever arm is moved and the spring compressed.
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