Document reJGR3Qj84j2byNLX84BwBNg0

HOISTING APPARATUS AND CONVEYORS Fig 18*17. Some details for boom-indicating device that shows ihe safe load with the boom at any angle. Notes (1) Verify all dimensions of the crane before fabricating the Indicator. (2) After assembling the Indicator, ascertain from the manufacturer of the crane the radii at which each additional 1,000 pounds may be lifted safely. Raise or lower the boom to give the desired radius and paint the figures on the dial at the proper point. (3) Note that the boom radius is from the center pin of the crane, and not from the boom hinge pin. From Consolidated Edison Company of Now York and from "Handbook of Rigging "WE Rounagol (O 1950, McGraw-Hill Book Company) in safety, be must have an unobstructed view of the load book and the point of op eration at all tunes He must also be able to see ahead of the crane when it is traveling on the ground, whether the chassis is mov ing forward or backward On some cranes, visibility ahead is ob structed, and the operator must use extreme caution A crane operated after dark should have clearance lights Floodlights should illumi nate the area beneath the boom, and lights mounted on the underside of the boom are recommended A warning bell or hom is a necessary piece of equipment for a mobile crane Men should be kept beyond the range of the cab swing and out from under the boom and the load Locomotive and automotive cranes fre quently present a serious shear hazard be tween the side of the operator s cab near the counterweight and the side of the car body or chassis. Many a man has been lolled by being caught in this shear point Fig 18-18 shows one way of guarding this loca tion on a locomotive crane A guard consisting of two segments of metal attached one to each side of the cab and suspended in a horizontal position by chains is available commercially This guard completely covers the shear points m all positions of the cab Since legal restric tions ou the width of vehicles traveling on highways prevent use of such a guard on an automotive crane, other methods must be employed An alarm can be installed to sound when an operator first touches the slewing lever and before the crane begins to move, so the man has time to jump clear of the hazard Also, a bar gate can be installed, so placed that a man must move it to reach the box of tools, shackles, dips, and similar items that usually is located on the chassis Movement of the gate causes an alarm to sound in the crone cab, warning the operator not to slew the crane Mirrors can be placed so that the opera- J8-22