Hand book of calculations for engineers and firemen : Relating to the steam engine, the steam boiler, pumps, shafting, etc. . resents a con-venient method in building-brick chimneys for steam plantswhich has been observed by theauthor, as used by Glasgow,Scotland, masons and crane at B enables theworkmen when the brick andmortar are raised, to swing itaround to the point where it is toFig. 11. be laid or to a platform near it. The lower cord of the rope C D is connected with a wheel andaxle ; in the illustration, it may be seen, that instead of thewheel and axle we might fasten a
Hand book of calculations for engineers and firemen : Relating to the steam engine, the steam boiler, pumps, shafting, etc. . resents a con-venient method in building-brick chimneys for steam plantswhich has been observed by theauthor, as used by Glasgow,Scotland, masons and crane at B enables theworkmen when the brick andmortar are raised, to swing itaround to the point where it is toFig. 11. be laid or to a platform near it. The lower cord of the rope C D is connected with a wheel andaxle ; in the illustration, it may be seen, that instead of thewheel and axle we might fasten a horse to the rope, or attach asweep to the top of the axis and join a team of horses to theend of it to expedite the work. The employment of this device, in sufficiently large chimneys,enables the builder to dispense with the use of scaffolding, theworkmen building into the corners of the chimney, as the workprogresses, a ladder of \ or \ inch round iron every fifteen inches,to enable them to go up and down in the interior of the a large expense is saved in cost of scaffold, and the risk isless for the 64 Hand Book of Calculations. THE PULLEY. Fast and loose pullies. These are shownin Fig. 12 where the movable block A car-ries the weight with a fixed counterpartB. Here the rope is attached by one endto the fixed block and is passed over themovable and fixed pullies from one to theother in succession, the power being ap-plied to the other end. This system isknown as fast and loose pulley blocks. The fixed end of the rope is sometimesfastened to the movable block. To find the power necessary to balancethe weight by the means of a system offast and loose pulleys. EtJLE 1. Divide the weight by the number ofropes by which it is carried; that is byFig. 12. the number of ropes which proceed from the movable block. The quotient is the power required to bal-ance the weight. cylinder cover weighing 1200 lbs. is lifted by a pair ofblocks of two sheaves each, t
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