| 摘要 |
A stairway lift for use by an invalid or handicapped person has at the upper end of the stairs a drive sprocket, at the lower end of the stairs an idler sprocket, and a pair of tubular guides between the sprockets. An endless conveyor element in the form of a cable provided with a succession of closely spaced balls is displaceable within this guide and is connected to a carriage so that rotation of the drive sprocket can move this carriage up or down along the stairway. The idler sprocket is permanently connected to a centrifugal brake that stops displacement of the conveyor element whenever its speeds exceeds a predetermined maximum safe level. Furthermore the cable and the balls are relatively dimensioned so that the cable can transmit compressive forces to the idler sprocket and the brake in the event of cable rupture immediately above the carriage.
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