| 摘要 |
A safety brake device (1) for hydraulic elevators acts by arresting the axial movement of the elevator ram (3) with respect to the main hydraulic cylinder (5) of the elevator. The safety brake (1) utilizes two lever acting brake arms (27) lined with an accretable metal (31), for example annealed copper, as the friction material. When actuated, the brake arms (27) contact the ram (3) circumferentially to slow and stop the falling ram. The lining material (31) is machined inside the brake arms (27) to a diameter slightly less than the diameter of the ram (3), and when actuated, the accretable material (31) on the brake arms (27) contacts the ram (3) with sufficient frictional force to stop the downward motion of the ram (3). The safety brake (1) may be actuated by loss of hydraulic pressure, by an electronic signal from a hydraulic pressure detector, by down overspeed or by an uncontrolled down motion detector. In the case of the hydraulic pressure loss, reapplication of normal pressure in the hydraulic cylinder (5) will automatically reset the brake (1). The safety brake device (1) can also be configured for use as a safety brake on other hydraulic or pneumatic cylinders or for use as a safety brake on cable-actuated traction elevators.
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