RETRIEVAL AND FALL ARREST SYSTEM FOR MANHOLE APPLICATIONS

摘要

A foldable hoist, fall-arrest and recovery system to be used in connectio n with a rectangular manhole guard having vertical posts at four corners of the guard including an upper structure having four elongated support members forming a pyramid shaped structure with the base of each of the support mem bers being securely mounted to the top of a post on the manhole guard and th e other ends of the support members being pivotally connected to an apex so that the upper structure can be folded for storage and shipment when disconn ected from the base and means connected at the apex for raising and lowering workers and/or cargo into and out of the manhole or for arresting the fall or recovering a worker.