. The railroad and engineering journal . il entirely free. The cylinder incloses aniron piston, the rod of which has a rectangular section,thus preventing any rotary movement. At the lower endof this rod is carried a steel block, which forms the ham- Vol. LXIII, No. 2.] ENGINEERING JOURNAL. 61 mer proper and which strikes on an anvil fixed to the bed-plate. The cylinder B has its upper head of cast iron madewith a recess greater in diameter than that of the piston ;within this recess is placed a light plate which works freelylike a piston. Steam is admitted to this head above theplate, as show
. The railroad and engineering journal . il entirely free. The cylinder incloses aniron piston, the rod of which has a rectangular section,thus preventing any rotary movement. At the lower endof this rod is carried a steel block, which forms the ham- Vol. LXIII, No. 2.] ENGINEERING JOURNAL. 61 mer proper and which strikes on an anvil fixed to the bed-plate. The cylinder B has its upper head of cast iron madewith a recess greater in diameter than that of the piston ;within this recess is placed a light plate which works freelylike a piston. Steam is admitted to this head above theplate, as shown at M, and thus serves as an elastic cushion ishes in this reservoir. The capacity of the latter can beincreased by the addition of water. The steam which itcontains produces a counter-pressure and causes the pistonto ascend as soon as the exhaust-port above it is openedand the upper end of the cylinder placed in communicationwith the air. This steam is not exhausted, but acts as asimple spring to lilt the hammer after the down THE FARCOT DOUBLE ACTING HAMMER. to prevent any shock to the upper part of the cylinder, incase the stroke of the piston is prolonged too much. In this system the frame is made hollow, and it forms areservoir in which steam is kept at a constant pressure—•about two atmospheres—by means of a balanced valve,which admits fresh steam whenever the pressure dimin- The result of this arrangement is that the waste space inthe steam-chest and ports, which in other hammers occa-sions loss of steam, is dispensed with. The force of the blow is regulated by the pressure andby the duration of the admission of steam above the pis-ton ; this steam forces down the hammer, at the same time 62 THE RAILROAD AND [February, 1889. compressing the steam in the reservoir A, which ought tobe kept at a pressure at least three atmospheres belowthat of the boiler. As soon as the valve is left free it israised hy springs placed on the rod L, and, the steamabove the pi
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectrailroa, bookyear1887
