08 TECHNOLOGY. 
Pl. 12, fig. 6, is a side view of a crane generally used in foundries ; jig. 7 
is a top view of the same. It is entirely of iron; the frame consists of two 
plates separated by cross-pieces and held together by screw-bolts, 4A; 8 is 
the post, c the stay, p the jib; the gudgeons, p p’, of the post turn on fric- 
tion rollers, as shown in fig. 8. The force is applied at the winches, 0, on 
the axle of the pinion, x, which drives the spur-wheel, m, on the axle of which 
is another pinion driving the spur-wheel x, which carries round the drum, t. 
On the axle of the pinion n is a ratchet-wheel, into which a catch or detent 
falls to prevent the load from descending when the power ceases to act. The 
chain passes from the drum over the pulleys, q, 1, and n, to the load. Besides 
the circular motion about the gudgeons, a rectilinear motion towards or 
from the centre can be given to the load in this crane by means of the 
following construction. The pulley, u, is attached to a small truck, e, which 
can be drawn along the track, t, by means of the rack, F; the latter is 
driven by the pinion, p, which is turned by means of the rope, m n, wound 
several times around the drum, g, on the axle of pP. 
Another crane of French construction, composed of wood and cast iron, 
and intended for raising very heavy loads, is represented on pl. 12, jig. 1 
being a view from behind, and jig. 2 a side view; jig. 8 shows the arrange- 
ment of the wheels on a larger scale. It is supported entirely at the lower 
end on the axis A, which is a hollow cast-iron cone (a section being partly 
shown in jig. 2) turning on a gudgeon, B, at the lower end, and at the top in 
an iron collar, c, which are fastened in a pier of solid masonry. The jib, £, 
and stay, Fr, are of wood; the drum, a, on which the chain, 7, is wound, and 
the wheelwork arms, @ a, which are attached to the post. The operation of 
the machinery is readily understood from the figure. In order to sustain 
the load when raised, and to allow it to descend slowly when desired, a 
small drum, 7, is attached to the spur-wheel, 5, having a ratchet-wheel and 
brake, as shown on a larger scale in jigs. 4 and 5. 
Pl. 12, fig. 9,is a drawing of a very ingenious crane in the machine-shop 
of Maudslay, in London, which is mounted on wheels in a room used for 
setting up large engines, and which serves for raising and transporting the 
heavier parts of the engines and for adjusting them in their positions. It 
has two arms, @Q, which are movable about the bolts, a a, and may be 
raised or lowered by means of the chains attached at 6d and wound around 
the drum, a, when it is desired to bring the load nearer to or further from 
the centre of the crane. The drum, A, turns with the cog-wheel, B, which 
is driven by an endless screw on the spindle, x, which also carries the 
wheel, p; the latter is driven by the pinion, r, when the spoke-wheel, a, is 
turned by hand. The load is raised at one arm only, while at the other a 
counterpoise is suspended, which descends as the load is raised, and vice 
versa, and serves to establish the equilibrium of the crane. The chains by 
which the load and counterpoise are suspended are attached to the arms at 
ec, and passing over the pulleys, m and 3, are wound over the drum, x, the 
axle of which rests in bearings at d, which are set into the post, r. The 
force is applied at the crank, 0, and turns the drum by means of the pinions, 
e and m, and the spur-wheels, n and 1; if lighter weights are to be raised 
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