. Steam shovel mining, including a consideration of electric shovels and other power excavators in open-pit mining . oal consumptiondue to the use of a boiler of large steam capacity, the ability ofthe dipper to take large boulders and full loads and its sim-plicity due to the elimination of the bail and the increased speedand ease of the manoeuvres making faster loading. In severeservice it was found that the earlier designs were not strongenough, so that when competing with the chain-type of shovel,the delays due to breakdowns were a serious strengthening the shovel to the ru
. Steam shovel mining, including a consideration of electric shovels and other power excavators in open-pit mining . oal consumptiondue to the use of a boiler of large steam capacity, the ability ofthe dipper to take large boulders and full loads and its sim-plicity due to the elimination of the bail and the increased speedand ease of the manoeuvres making faster loading. In severeservice it was found that the earlier designs were not strongenough, so that when competing with the chain-type of shovel,the delays due to breakdowns were a serious strengthening the shovel to the ruggedness of the chain-type, its advantages of design, fuel economy, extra lift, easeof operation and increased loading speed when working infavorable ground, recommend it to favorable attention. It may be mentioned that just prior to 1906 the Allis-ChalmersCompany of Milwaukee brought out a wire-rope shovel. This hadsome unique features including a scheme to relieve the weighton the boom and turntable by so leading the ropes that theworking strains are resolved into a lifting component, made THE POWER SHOVEL 29. 30 STEAM SHOVEL MINING effective at the foot of the boom, thus lessening the load on theturntable and reducing the strains and turning friction so thatthe swing is made more rapidly. To do this, the hoisting drumis geared directly to the engine, and from the drum the rope islead over a sheave, suspended from the A-frame, to a differentialdrum placed on the boom. This differential drum is made upof three concentric drums, one of large diameter in the centrecarrying the single rope from the hoist, and two drums of acommon smaller diameter, rigidly attached to both sides of theformer, carrying the twin ropes over the head sheave to the dip-per back. Their respective diameters are about 7 ft. and 3^ the rope on the hoisting drum causes the hoisting ropeto run off the large diameter of the differential drum, and thetwin ropes atached to the dipper to wind on the s
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Keywords: ., bookcentury1900, bookdecade1920, bookpublishernewyo, bookyear1920
