Book-bot.com - read famous books online for free

Scientific American Supplement, No. 312, December 24, 1881 by Various
page 5 of 129 (03%)

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.

The principal dimensions of the crane are, total height of lift 46
DigitalOcean Referral Badge