An
iron house, of which the framing only is shown, extends from the
gearing right back to the boiler, forming a most spacious engine room
and stokehole. A separate donkey engine is provided for feeding the
boiler. The truck is furnished with legs under which packings can be
wedged so as to relieve the load on the wheels when block-setting. The
slings seen under the boiler are for hanging a concrete balance
weight; this will weigh about 20 tons. The weight of the crane itself
without load or ballast is about 80 tons. The crane was tested under
steam with a load of 19 tons with the most satisfactory results; the
whole machine appeared to be very rigid, an end often very difficult
to obtain with portable wrought-iron structures and live loads. The
result in the present case is probably greatly due to the careful
workmanship, and to the fact that the sides and ends of the plates are
planed throughout, so that the webs of the girders get a fair bearing
on the top and bottom plates.
The crane showed itself to be very handy and quick in working, the
speeds with 19 tons load, as actually timed at the trial, are: lifting
16 ft. per minute, racking motion 46 ft. per minute, slewing through a
complete circle 90 ft. diameter, four minutes, equivalent to a speed
at load of 60 ft.
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