The Construction of Cranes and Other Lifting Machinery ... by Edward Charles Robert Marks

Author:Edward Charles Robert Marks
Language: eng
Format: epub, pdf
Publisher: Technical Pub. Co., Ltd . [etc., etc.]
Published: 1904-03-25T05:00:00+00:00

n the usual donble or ram's horn shape, with a sbnckle I attached for couTenience in lifting lighter IohIb. The boiler Rmplojed ia Nicholson's pEiteut, and is 9ft. high fay 4ft. 6in. diameter, conatrncted from mild steel plates and carrying a working preesnre of 801b. per square inch, the hydraulic teat having been twice that amount. The boiler and the vhole of the engine work and gearing of the craue are so arranged as to occupy as little head room aa possible. In the illustration the et«am cylinders are shown horizontal, but in order to obtain greater compaetneaa, and facility of working, the two eogine cylinders of the 75 ton steam crane now under notice are arranged diagonally, having a diameter of 9hin. and allowing; a piston stroke of 14in. The transverse travelling motion consicta of bevel and spur wheels geared np to the axleg of the crab and controlled by double mctton cones; whilst the motion for travelling the whole crane longitudinaUy has bevel and spar gear with square cross shafts (having bearings attached to one of the girders, bnshed with white metal), and controUedalEO by large donble friction cones, which enable the crane to be travelled in either direction without stopping or reversing the engines ; they are of ample diameter, in order to give a good wearing surface, and are controlled bj; screw lever and light hand wheel. The two transverse girders and also the end carriages are bnilt I up in bos section with plates and angles, the girders being provided with steel rails to anit the wheels of the crab; tfa« ] end carriages are mounted upon doable-flanged steel-tyred I travelling wheels, set to a gauge or span of 50f r.. The crab is provided with gun-metal bearings, and all the principal axles and shafts are of mild steel ; steel pinions are also employed. The boiler is placed on one side and projecting beyond one of the cross girders, whilst the feed-water tank is secured on the opposite side of the crab and proJRcting beyond ' the other cross girder, tbaa obtaining a good distribution of ' the dead weight and mnre perfectly balancing the whole | machine. A powerful brake is placed upon the second motion | crab shaft, controlled by a screw !everand hand wheeL The whole of the crane motions are within easy reach and control of one man stationed on the platform attached to the crab.

Coming now to the second class of overhead steam I travellers in which the necessary motive power is supplied to J the machine from some external source, we find that two 1 systems are in general employment to e(i\ ct the transmission J of power from the source of sapply to the traveller itself, j The first of these systems that we shall notice is tboj

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