. Supplement to Spons dictionary of engineering, civil, mechanical, military, and naval. matter of great importance in hammers of this class to be able to vary the power of theblow without altering the speed, and this is effected in this hammer by means of the valve r, whichis placed at the bottom of the cylinder L. When r is closed, the air which is compressed under thepiston P absorbs the force exerted by the downward stroke of the hammer, without in any wayaffecting its speed. HAMMERS. 705 Alfred Davys power hammer is shown in Figs. 1424 to 1426; Fig. 1424 is a front elevation,Fig. 1425 a s
. Supplement to Spons dictionary of engineering, civil, mechanical, military, and naval. matter of great importance in hammers of this class to be able to vary the power of theblow without altering the speed, and this is effected in this hammer by means of the valve r, whichis placed at the bottom of the cylinder L. When r is closed, the air which is compressed under thepiston P absorbs the force exerted by the downward stroke of the hammer, without in any wayaffecting its speed. HAMMERS. 705 Alfred Davys power hammer is shown in Figs. 1424 to 1426; Fig. 1424 is a front elevation,Fig. 1425 a side elevation, and Fig. 1426 an enlarged view of the tup and its connections. Theshaft D is so arranged as to be capable of being raised bodily, so as to increase the distance betweenthe face of the tup C and of the anvil B; by which means the hammer may be caused to give anynumber of light or heavy blows without interfering with its speed, or it may be so far raised as to befree to oscillate without giving any blow. At the upper part of the standards A are two guides G, 1424. between which are placed the bearing blocks F, which carry the shaft D ; the blocks F being free toslide up and down between the guides G. To the rear guides are pivoted the levers H, which passthrough slots in G. At the back of these levers are fixed weights W sufficiently heavy to counter-balance and lift the hammer tup C and shaft D with their connections, and at their forward endsthe levers are connected by means of the rods I to the treadle K. The parts H, which pass throughthe guides G, are slightly rounded on their lower and upper edges. When the hammer is out ofgear, the levers H cause the blocks F to rise in the guides by theaction of the counterweights W ; and thus lift the driving shaft D, ^*^®- and with it the tup C, so that the latter will continue to oscillatewithout striking the face of the anvil. By pressing down thetreadle K, C will strike the object placed beneath it, the force o
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectenginee, bookyear1879
