| 摘要 |
An additional emergency brake apparatus is provided for an elevator installation which contains a car, counterweight, hoist ropes, drive sheave, motor, brake and elevator car safety. This additional emergency brake apparatus acts directly at the drive sheave and is intended to accomplish emergency braking in the upward direction of travel of the car, because in this travel direction the elevator car safety cannot be used for a number of reasons. A star-shaped brake element located at the shaft of the drive sheave is permanently pressed by a cup spring against an annular end surface of the drive sheave and normally rotates together with the shaft of the drive sheave. In the event of overspeed in the upward travel direction of the car, a tripping mechanism displaces an arresting bolt between the spokes of the star-shaped brake element, blocks the latter and thus produces an appropriate braking torque by means of braking plates bearing at the annular end surface. This braking torque can be greater by an order of magnitude than the braking torque which can be produced with the normal operating brake.
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