IMPROVEMENTS IN FLOATING CRANES
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by the said Walter Hunter at the
Office of the Commissioners of Patents on the 28th July 1881.
WALTER HUNTER, of No. 202, Bow Road, in the County of Middlesex,
"IMPROVEMENTS IN FLOATING CRANES."
This Invention has for its object improvements in floating cranes.
For the purpose of lifting boilers into and out of stean ships, and for like or
other purposes, I construct a floating crane capable of raising many, say, 30 tons,
more or less, and of swinging such a load from one side to the other of the vessel
or float upon which the lifting apparatus is carried, the radius being as large as is
required, say, 45 or 50 feet. The vessel or float has a beam sufficient to form a
steady base, and is of a convenient length from bow to stern. On this vessel or
float I mount a turn table in a central position. The turn table carries the whole
of the crane gear and shear legs set at the requisite inclination. The turn table
also carries upon it a counterpoise which can be traversed by an engine provided
for the purpose, and fitted with screw gearing from and towards the centre of the
turn table. The movement takes place along guide rails provided for the purpose.
By shifting this counterpoise the float or vessel can be kept on an even keel or
nearly so whilst the load is lifted; and in swinging, as the load and the counterpoise
move together around the central pivot, but little change in the trim of the float or
vessel need result.
The vessel is propelled by twin screws driven by suitable engines, and the fore
part of the vessel is strengthened so that the weights lifted may be placed upon
the deck and transported to any desired spot.
The floating crane is very valuable for docks, as it prevents the necessity of
moving large ships from their berths. The crane can be moved alongside vessels,
and any weights removed from them without stopping any other operations, such
as loading or repairs, which may be proceeding at the time.
I also fit the crane, vessel with steam capstans, to afford greater facilities for
moving about a dock and moving alongside vessels.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Walter Hunter in the Great Seal Patent Office on the 28th January
1882.
"
WALTER HUNTER, of No. 202, Bow Road, in the County of Middlesex.
IMPROVEMENTS IN FLOATING CRANES."
This Invention has for it object improvements in floating cranes.
For the purpose of lifting boilers or other heavy weights into and out of steam
ships and for like or other purposes, I construct a floating crane capable of raising
many, say, 30 tons, more or less, and of swinging such a load from one side to the
other of the vessel or float upon which the lifting apparatus is carried, the radius of
the circle in which the lifting chain revolves being as large as is required, say, 45
or 50 feet, more or less. The vessel or float has a beam sufficient to form a steady
base, and is of a convenient length from bow to stern. On this vessel or float I
mount a turn table in a central position. The turn table carries the whole of the
crane gear and shear legs set at the requisite inclination. The turn table also
carries upon it a counterpoise which can be traversed by an engine provided for
the purpose, and fitted with screw gearing for moving the counterpoise from and
towards the centre of the turn table. The movement takes place along guide rails
provided for the purpose. By shifting this counterpoise the float or vessel can be
kept on an even keel or nearly so whilst the load is lifted; and in swinging, as
the load and the counterpoise move together around the central pivot, but little
change in the trim of the float or vessel need result.
The vessel is propelled by twin screws driven by suitable engines, and the fore
part of the vessel is strengthened so that the weights lifted may be placed upon
the deck and transported to any desired spot.
This floating crane is very valuable for docks, as it prevents the necessity of
removing large ships from their berths, and taking them to fixed shear legs for the
purpose of putting into them or taking out of them heavy weights.. The crane can
be moved alongside vessels, and any weights removed from them without stopping
any other operations, such as loading or repairs, which may be proceeding at the
time.
I also fit the crane.vessel with steam capstans, to afford greater facilities for
moving about a dock and moving alongside vessels.
In order that my said Invention may be most fully understood and readily
carried into effect, I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
may be
Figure 1 is a vertical section of my improved floating crane; Figure 2 is a plan
of the same with some of the. upper works removed. The hull, as will be seen, is
a float or barge like structure of sufficient beam to ensure stability, and of sufficient
displacement to support its own weight and that of the heaviest load it
designed to lift. It is fitted with twin screws, and these are driven by the
engines a, a. The engines on the port side can also be applied to driving the
capstans b, b, through an horizontal shaft which can be clutched at pleasure fast
with the crank shaft of the engine. Another clutch serves to connect and dis-
connect the propellor. The engines may or may not be fitted with a condensor.
c is the boiler by which the engines a and the other engines of the structure are
supplied with steam.
d is a post strongly built in the centre of the float, to serve as the pivot for the
turn table.

page_text: e is a circular guide rail laid on the deck of the float concentric with the pivot d,
and supported by a wrought iron cylinder the whole depth of the hull, and built in
with it.
fis the turning platform; it is built upon strong beams upon which the shear
legs are stept. 1, f¹, are wheels carrying the platform f and running upon the
guide rail e.
At the centre of the platform there is also a frame ƒ³ carrying
antifriction rollers arranged in a circle around the post or pivot d.
g is the steam pipe passing up through the pivot by another pipe jointed to it;
it supplies the two engines h and i carried upon the turning platform. g' is an
annular exhaust pipe conveying the exhaust steam to the condensor, there being
an air space between the steam and exhaust pipes.
, k, are the shear legs, they carry at their upper end sheaves l, around which
the lifting chain passes to the load to be raised in the usual way. k¹, k¹, are tie
bars connecting the head of shear legs with platform f. The framework of the
platform to which the tie bars are attached is so arranged, that the strains
induced by the varying position of the heavy counterpoise s, due to the different
weights lifted, are properly and evenly distributed through the whole structure.
There are two lifting chains, one a single chain for weights up to about 8 tons, and
the other reeved through blocks to lift heavy weights.
m is the windlass barrel upon which the lifting chain is wound in order to lift
the load. The barrel m has a worm wheel on its axis, and with this a worm
driven by the engines h engages, so that these engines supply the power for lifting
the load. They also serve another purpose, viz., to rotate the turning platform to
swing the load. For this purpose there is a bevilled wheel h¹ on the engine shaft
with which the wheels n¹, n², are always in gear; and at pleasure either of these
wheels can be made fast with its axis by a friction clutch. This axis, by a
bevelled pinion at its end drives the intermediate wheel o, and this, by the spur
gear indicated in the Drawing, drives the shaft p on which is a pinion driving a
wheel q. Two of the wheels f¹ supporting the turning platform carry rings of
teeth f, and with these pinions gear, and by means of these pinions the wheels are
rotated when the turning motion is required.
One of the pinions is on the axis of the wheel g, the other on the axis of a
similar wheel q¹ on the other side of the turning platform. The wheel q¹ is driven
by a pinion on the axis r which receives its motion through equal spur wheels
from the shaft p. The turning of the crane may also be effected by any other
suitable arrangement of gearing.
8 is a massive counterpoise which can be moved along guide rails to and from
the centre of the turning platform f. There is a separate engine i for traversing
the counterpoise; the crank shaft of this engine has two bevilled pinions upon it
engaging with corresponding wheels on the horizontal screws t, t, which work with
nuts fixed upon the counterpoise, or the screws may be driven from the engine by
any suitable gearing..
The turn table is roofed over to shelter the workmen from the weather and
protect the mechanism.
I claim my improved floating crane substantially as described, whether it be
worked by steam, hand, or other motive power.
In witness whereof, I, the said Walter Hunter, have hereunto set my hand
and seal, this Twenty-eighth day of January, in the year of our Lord One
thousand eight hundred and eighty two.
WALTER HUNTER. (L.S.)