. Material handling cyclopedia; a reference book covering definitions, descriptions, illustrations and methods of use of material handling machines employed in industry . ce and a movable jib. The jib carries atrolley or traveler which is racked across the jib by meansof a hand chain. The hoisting hook is rigidly fixed to thetrolley and the load is raised or lowered by moving thejib itself instead of moving the hook as on other typesof jib cranes. The jib is suspended by four chains, twoat each end, the chains from the outer end of the jib pass-ing over sheaves on the end of the inclined brace
. Material handling cyclopedia; a reference book covering definitions, descriptions, illustrations and methods of use of material handling machines employed in industry . ce and a movable jib. The jib carries atrolley or traveler which is racked across the jib by meansof a hand chain. The hoisting hook is rigidly fixed to thetrolley and the load is raised or lowered by moving thejib itself instead of moving the hook as on other typesof jib cranes. The jib is suspended by four chains, twoat each end, the chains from the outer end of the jib pass-ing over sheaves on the end of the inclined braces, and thechains from the inner end passing over sheaves on themast. All four of these chains are also used to suspendthe lifting-cylinder of the hoisting apparatus. They areconnected with the upper end of the cylinder, either beingattached directly to it or passing around sheaves securedto the top of it. The chains are arranged so that the cylin-der always tends to hang plumb regardless of the posi-tion of the load on the jib. The steam or air supply line is piped to a closed cylinderor pressure tank placed in any convenient location in the 174 HOISTING MACHINERY. CRANES 175 ground near the crane, or upon the crane itself. Fromthe bottom of this cylinder a pipe passes through the bedplate of the crane and connects with a U-shaped stuffing-box in the bottom of the mast. A control valve is placedin this pipe, near the ground cylinder within easy reachof the operator. The piston-rod of the lifting-cylinder is»hollow and its lower end is fastened to a projection ofthe bottom gudgeon of the mast pivot, the passage-waybeing continued through the gudgeon projection and con-necting with the stuffing-box in the mast. From thestuffing-box the passage-way leads out through the pipe inthe bed plate and connects with the ground cylinder. Theground cylinder is filled with water to within 12 or 18inches of the top, the space above the water being occu-pied by air. In this type of hoist the
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Keywords: ., bo, bookcentury1900, bookdecade1920, booksubjecthoistingmachinery
