SHOP TOOLS.
I 24
together. The machinery and ladle are carried by a cradle witha pivot fixed at the bottom of the ovlinder, on which the cradlehas a sligbt rocking movement. The ladle when full contains12 tons of Steel. A weight is adjusted so as to balance thecradle when the ladle contains half its Charge, or 6 tons of Steel.A revolving port on the top of the crane post conveys water toand from the cylinder. A stop is provided to preverit thecradle from drooping when the preponderance of weight is onthe ladle end, but if the bottom of the ladle be lowered upouanything unyielding, the frame simply liinges upwards on itspivot. The pipe conveying water to and from the cylinder isarranged so that the lower end terminates in a hole which isbored through the centre of the ram, the upper end also enter-ing the post to convey water through the top bearing.
It will be seen that provision has to be inade to balance thehalf weight of the Steel, which is not balanced by the counter-weight. To accomplish tliis, chains are led from each end ofthe girders forming the platform, over sheaves fixed on a strongframe at the top, and forming part of the crane post iminediatelyunder the top socket, so that the slieave frame can rotate hori-zontally with the crane post and cylinder. The two sets ofchains, after passing over their respective sheaves, descend to aheavy balance weight of annular form, surrounding the upperportion of the crane post, which acts as its guide. The point ofconnection of both sets of chains is the same, and is in a planepassing through the centre of gravity of the weight, so that itmay hang indifferently on eit her one or the other set of chains.The chains are a succession of flat steel links connected by pins.
If the ladle is half full, then the fixed counterweight balancesthis amount of steel, and the annular balance distributes itsweight equally between the two sets of chains, neutralising somuch of the dead weight of the platform, and so saving waterpressure in the cylinder. If the ladle is full, the half weighttends to bring down the ladle end of the platform, but is pre-vented (owing to its rigidity), without the opposite end beingraised to an equal extent. The depression of the ladle end,