Speed retarder

摘要

A speed retarder used in combination with a flexible member such as rope, cable, or chain to control the speed of the flexible member relative to the speed retarder. The speed retarder is particularly suited for use in applications where it is desirable to lower a load at a controlled rate of speed from a higher elevation to a lower elevation. Such applications include fire escape devices and safety backup devices for elevators. One specific embodiment of the speed retarder comprises a frame having an axle on which is mounted a pair of rollers each having a tapered surface around which a flexible member is trained and retained between the surfaces by means of guides. The wheels are mounted on the axle for combined rotary and outward sliding motion into brake pads carried by the frame outboard of the wheels. Tension on the flexible member combined with movement thereof causes the wheels to be forced outwardly into pressure engagement with the brake pads, thereby creating friction on the outsides of the wheels to slow the same and thus to retard the speed of the flexible member relative to the frame.