Farrow's military encyclopedia : a dictionary of military knowledge . osition ready for the next shot. Themarker for this target is provided with small disksmade of wood, tin, or iron, with hooks in the centerand each side of them, and painted to representcertain values. JIB-CBANE.—The mode of operating the hoistingand traversing mechanism of the larger sizes of theWeston jib-cranes is fully explained in the articleTrolleys. The details of the gearing whereby theseseveral motions are affected are as follows. Fig. 1is a cross-section taken at the foot of the mast of alarge jib-crane. A is the m
Farrow's military encyclopedia : a dictionary of military knowledge . osition ready for the next shot. Themarker for this target is provided with small disksmade of wood, tin, or iron, with hooks in the centerand each side of them, and painted to representcertain values. JIB-CBANE.—The mode of operating the hoistingand traversing mechanism of the larger sizes of theWeston jib-cranes is fully explained in the articleTrolleys. The details of the gearing whereby theseseveral motions are affected are as follows. Fig. 1is a cross-section taken at the foot of the mast of alarge jib-crane. A is the mast, to each side of whichis bolted a housing containing the gearing for oper-ating the two parts, X, and Y. of the main hoistingchain. Eacli of these housings is provided with ahorizontal shaft, revolving upon which is the wormwheel P, the hub of which covers the entire length or left hand housing, and its contained gearing, is thesame as that just described. Fig. 2, is a detail view of one of the chain wheels,R, with the chain guide, S, and stripper, V, showing. Hg. I. of the pin or shaft between its bearings. Over thehub of this wheel, is tlie pocketed clmin-wheel U,with tlucliain stripper V, and a chain guide. .S Thechain wheel is made separately from the worm wlicelto admit of easy removal and renewal when wornout. Heferring now to the right hand housing in thedrawing, () is the crank shaft extending through thehousing at riglit angles to the worm wheel shaft a-bove. Q is the worm, fitted upon the shaft, (), at itscenter, ami gearing into llie worm wheel, P. K. isaspur ])iiiii)ii, tittcil to one end of the shaft, (), and cap-able of sliding longitudinally tliereon. T isa smallguide sheave over which the slack of the chain fallsafter passnig aniiind the lower semi-circumfcniice ofthe chainwheel. K. The arrangement of the opposite
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Keywords: ., bookcentury1800, bookdecade188, booksubjectmilitaryartandscience
