IMPROVEMENTS IN DREDGING MACHINES
Year: 1877

page_text: LETTERS PATENT to John Keith Rennie and George Banks Rennie, both of
Holland Street, Blackfriars, in the County of Surrey, Engineers, for the In-
vention of "IMPROVEMENTS IN DREDGING MACHINES."
Sealed the 28th May 1878, and dated the 1st December 1877.
PROVISIONAL SPECIFICATION left by the said John Keith Ronnie and
George Banks Rennie at the Office of the Commissioners of Patents on the
1st December 1877.
JOHN KEITH RENNIE and GEORGE BANKS RENNIE, both of Holland Street, Black-
friars, in the County of Surrey, Engineers. "IMPROVEMENTS IN DREDGING
MACHINES."
This Invention has for its object the working of a bucket scoop for dredging
purposes by means of hydraulic power applied to the end of cranes or framework
projecting from the hull of a ship or vessel in which the machinery is placed. The
hull of the vessel which carries this improved dredging machine will be of suitable
size and form, made either of wood or iron, or a combination of them, and capable
of supporting one or more cranes or framework for lifting and lowering a bucket
scoop for excavating under water. The power for actuating the bucket scoop is
obtained by hydraulic pressure by means of a steam engine and boiler.
The steam machinery is so arranged as to work either hydraulic pumps for
supplying the necessary quantity of water to the accumulator under pressure, or it
may be disconnected from the pumps and adapted to work one or more screw pro-
pellers for moving the ship from place to place.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Jolin Keith Rennie and George Banks Rennie in the Great Seal
Patent Office on the 31st May 1878.
JOHN KEITH RENNIE and GEORGE BANKS RENNIE, both of Holland Stroet, Black-
friars, in the County of Surrey, Engineers. "IMPROVEMENTS IN DREDGING
MACHINES."
This Invention has for its object the working of a bucket scoop for dredging
purposes by means of hydraulic power applied to the end of cranes or framework
projecting from the hull of a ship or vessel in which the machinery is placed. The
hull of the vessel which carries this improved dredging machine will be of suitable
size and form, made either of wood or iron, or a combination of them, and capable
of supporting one or more cranes or framework for lifting and lowering a bucket
scoop for excavating under water The power for actuating the bucket scoop is
obtained by hydraulic pressure by means of a steam engine and boiler, or by steam
direct.
The steam machinery is so arranged as to work either hydraulic pumps for
supplying the necessary quantity of water to the accumulator under pressure, or it
may be disconnected from the pumps and adapted to work one or more screw pro-
pellers for moving the ship from place to place
And in order that our Invention may be clearly understood and readily practised
we will proceed to describe the Drawings hereto annexed.
Figure 1 shows a longitudinal section, and Figure 2 a plan of a floating vessel
having dredging apparatus mounted thereon, and arranged in accordance with our
Invention.
a is steam boiler; b, b, steam engines; c, c, hydraulic pumps; d, accumulator;
e, hydraulic cylinder for lifting or actuating bucket scoop by means of chains and
sheaves connected to bucket scoop; f, hydraulic cylinders for swinging cranc by
incans of chains connected with the wheel flat the base of the crane; g, bucket
scoop of iron or steel connected to a lever or arm g¹ of wood, iron, or steel, or con-
binations thereof, working between guide rollers h, h, being raised and lowered by
rack and pinion h', as shown, or otherwise. The bucket scoop 9 and arm g¹ are
supported by a wrought-iron or steel frame i, i, forming the jib of a crano moving
on pivots ¹, ¹, which are supported on a framing j. j. The boat is advanced of
moved forward by means of chains h, k, working over barrels or surging heads,
which are actuated by means of shaft and gearing in connection with the steam
engines.
The operation of the machine is as follows:-The boilers, engines, and pumps
when at work maintain the required pressure in the accumulator d, from which
pressure pipes are connected to the hydraulic cylinders e and f. The bucket
scoop is lowered to the required depth by means of the rack and pinion h'. The
valves in connection with the hydraulic cylinder e lift up the bucket scoop g by
means of the chains connected thereto, and, when raised to the required height, the
jib of the crane with the bucket scoop is swung either to the right or left by means
of the hydraulic cylinder f, and the contents of the bucket scoop are discharged by
releasing the bottom of the bucket, thus allowing the contents thereof to fall out
into a barge or on to an embankment. The crane is then swung into a central
position or thereabouts and the bucket lowered, and the same operation repeated,
the vessel being advanced by means of the advancing gear k, h, as the excavation
progresses. The same operation may be performed by taking chain direct to a
steam winch in lieu of being connected to hydraulic apparatus as previously
described.

page_text: Figures 3, 4, and 5 show an arrangement of apparatus for actuating a single
bucket scoop g without the intervention of hydraulic cylinders as previously
described. The manner of working is similar to that described, with the
exception that the bucket is raised and lowered by means of a chain worked on a
barrell actuated by a steam engine. This arrangement also shows means of
lowering the crane and framing on to the deck of the vessel so as to enable it to
pass under bridges with facility. This is effected by mounting the frame and jib
post on centres, 1, detaching the tension rods m, m, and lowering the frame in its
centres, as shown by dotted lines.
Having thus described the nature of our Invention for improvements in dredging
machines and the manner of performing or carrying the same into practice, we
would remark that we do not claim any of the parts separately, which are well
known and in common use, nor do we confine ourselves to the exact details herein
described, as the same may be varied without departing from our Invention, but
what we claim is,-
First. The improved arrangement and adaptation of hydraulic apparatus in com-
bination with a bucket scoop g mounted upon the hull of a ship or floating vessel
for dredging under water, substantially in the manner herein-before described with
reference to Figures 1 and 2 of the Drawings hereto annexed.
Secondly. We claim the improved arrangement and adaptation of a single
bucket scoop g mounted upon the hull of a ship or floating vessel, and actuated by
means of steam winches and chains for dredging under water, substantially in the
manner herein-before described and represented by Figures 3, 4, and 5 of the
Drawings hereto annexed
Thirdly. We claim the improved general arrangement and construction of
dredging machines for actuating a single bucket scoop g under water, substantially
in the manner herein-before described and represented in the Drawings hereto
annexed.
In witness whereof, I, the said George Banks Rennie, on behalf of myself
and the said John Keith Rennie, have hereunto set my hand and seal,
this Twenty-ninth day of May, in the year of our Lord One thousand
eight hundred and seventy-eight.