| 摘要 |
<p>The invention includes a brake system for a hydraulic ram (3) or another cylinder, that can be employed as an emergency brake for a lifting elevator. When actuated, the brake arms (27) contact the ram circumferentially to slow and stop the falling ram. The brake arms are preferably lined with accretable material that frictionally engages the ram to stop the downward motion of the ram. The brake system may be actuated by the loss of hydraulic pressure, by an electronic signal from a hydraulic pressure detector, by down overspeed sensor (40) or by an uncontrolled down motion detector. According to another aspect of the present invention, a controller, which is preferably a programmed control system, compares the actual motion of the elevator as sensed by a detector to a desired motion. Under certain conditions, if the actual motion differs from the desired motion, the controller actuates the brake. </p> |
