Scientific American Supplement, No. 312, December 24, 1881
The machine illustrated on first page has been constructed for Port Alfred Harbor, this being one of several harbors now being made by Sir J. Coode in South Africa. The pier for the construction of which the crane will be employed will consist of concrete blocks laid on what is known as the overend system. The blocks, being brought on trucks direct from the block yard to within the sweep of the machine, are raised by it, swung round, and accurately set, the machine being continually traveled forward as the work advances. The bottom blocks are laid on bags of concrete previously deposited by the crane out of boxes with flap bottoms.
The present machine has been specially designed throughout, and represents the most complete development which block-setting plant has yet attained.
The most striking features of the crane are, the great range of all the motions, the large radius, and the method of providing for the latter by a horizontal jib suspended from a king-post. It was at first intended to have a straight inclined jib, and to alter the radius by pivoting this round its lower end, as is commonly done; it occurred, however, to Mr. Matthews, M.I.C.E., representing Sir J. Coode, that the plan eventually adopted would be in many ways preferable; the crane was therefore constructed by Messrs. Stothert & Pitt with this modification, and as far as can be judged from the trial with proof load, the arrangements can hardly be surpassed for quick and accurate block-setting. In cranes with derricking jibs it is necessary to connect the derrick and hoisting gears in such a manner that a variation of the radius may not affect the level of the load; this plan answers sufficiently well for ordinary purposes, but for block-setting it is requisite to have extreme accuracy in all the movements and great quickness in changing from one to another; the arrangements adopted in foundry cranes, in which all the motions are entirely independent of one another, seems therefore more suited for this kind of work. Other not inconsiderable advantages are also secured by the adoption of the foundry crane type, the amount of clear headway under the jib being much increased, and the difficulty avoided of making a jib sixty feet long sufficiently stiff without undue weight.
Various
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SCIENTIFIC AMERICAN SUPPLEMENT NO. 312
NEW YORK, DECEMBER 24, 1881
AMERICAN ANTIMONY.
THE STEAM-ENGINE EMPLOYED FOR MANUFACTURING PURPOSES.
THE EVAPORATIVE CONDENSER.
STEAM NAVIGATION.
MARINE GOVERNORS.
LIGHT ENGINES AND BOILERS.
THE PERKINS SYSTEM.
ETHER ENGINE.
THE QUICKSILVER ENGINE.
LOCOMOTIVE ENGINES.
BRAKES.
MOTORS.
TRANSMISSION OF POWER.
COMPRESSED AIR LOCOMOTIVES.
HYDRAULIC TRANSMISSION OF POWER.
ELECTRIC TRANSMISSION OF POWER.
THE MANUFACTURE OF IRON AND STEEL.
BRIDGES.
MACHINE TOOLS.
THE SEWING MACHINE.
AGRICULTURAL MACHINERY.
PRINTING MACHINERY,
METAL TURNING.
ROTARY CUTTERS.
WOOD WORKING.
WHAT MAY WE EXPECT OF IT.
ON THE SUMMIT.
A MIDNIGHT OBSERVATION.
PLANT LIFE ON HERALD ISLAND.
INHABITANTS OF THE CLIFFS.
PHOTOGRAVURE.
PHOTOGRAPHIC PRINTING BY VAPOR—ATMOGRAPHY.
THE
Scientific American Supplement.
PATENTS.