IMPROVE- MENTS IN DREDGING MACHINES
Year: 1868

page_text: LETTERS PATENT to Henry Oliver Robinson, of Glasgow, in the
County of Lanark, North Britain, for the Invention of "IMPROVE-
MENTS IN DREDGING MACHINES."
Sealed the 6th January 1869, and dated the 1st August 1868.
PROVISIONAL SPECIFICATION left by the said Henry Oliver Robinson
at the Office of the Commissioners of Patents, with his Petition,
on the 1st August 1868.
I, HENRY OLIVER ROBINSON, of Glasgow, in the County of Lanark,
North Britain, do hereby declare the nature of the said Invention of
"IMPROVEMENTS IN DREDGING MACHINES," to be as follows, that is to
say:-
This Invention relates to dredging operations as usually performed
for deepening rivers or for forming or deepening roadsteads, harbours,
canals, and docks.
In the ordinary dredging machine the operation is performed by a
revolving chain of buckets, which cut or dig into the material of the
bottom, and bring it up out of the water.

page_text: Under the present Invention the operation is performed by a spiral or
helical cutter placed in a cylinder, and either revolving in the cylinder or
otherwise fixed in it, and both revolving together. A tube is connected
to the cylinder, through which the material so cut or dug by the helical
cutter ascends up out of the water, and is received in punts or barges or
run out to the bank through a floating tube, as may be desired. When
the helical cutter revolves in the cylinder it is driven or worked by a
shaft, but when the helical cutter is fixed in the cylinder they are both
made to revolve together by suitable gearing. The cylinder with the
helical cutter is placed in a floating vessel in an inclined position, as in
the common dredger, and driven by a steam engine or other motor. The
action of the helice on the fluid material is to force it upwards through
the tube, but in order to ensure its ascent out of the water to any desired
height screw propellers are made to rotate within the tube, or the air
in the tube is exhausted by any of the usual modes. The helical cutter
or instrument thus constructed and placed is drawn or urged against the
bottom by a forward motion given to the vessel in the usual way.
The cylinder and helical cutter are made of suitable steel or chilled
iron.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Oliver Robinson in the Great Seal Patent
Office on the 30th January 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
OLIVER ROBINSON, of Glasgow, in the County of Lanark, North Britain,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of August, in the year
of our Lord One thousand eight hundred and sixty-eight, in the
thirty-second year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Henry Oliver Robinson,
Her special license that I, the said Henry Oliver Robinson, my
executors, administrators, and assigns, or such others as I, the said
Henry Oliver Robinson, my executors, administrators, or assigns, should
at any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might

page_text: make, use, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Inven-
tion for "IMPROVEMENTS IN DREDGING MACHINES," upon the condițion
(amongst others) that I, the said Henry Oliver Robinson, by an instru-
ment in writing under my hand and seal, should particularly describe
and ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Henry Oliver Robinson, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the accompanying
Drawings, and to the letters and figures, marked thereon, that is to
say:
My said Invention relates to dredging operations, as usually per-
formed for deepening rivers, or for forming or deepening roadsteads,
harbours, canals, and docks.
In the ordinary dredging machine the operation is performed by a
revolving chain of buckets, which cut or dig into the material of the
bottom and bring it up out of the water.
Under the present Invention the operation is performed by a spiral or
helical cutter placed in a cylinder, and either revolving in the cylinder
or otherwise fixed in it, and both revolving together. A tube is con-
nected to the cylinder, through which the material so cut or dug by the
helical cutter ascends up out of the water, and is received in punts or
barges, or run out to the bank through a floating tube, as may be
desired. When the helical cutters revolves in the cylinder it is driven
or worked by a shaft, but when the helical cutter is fixed in the
cylinder they are both made to revolve together by suitable gearing.
The cylinder with the helical cutter is placed in a floating vessel in an
inclined position as in the common dredger, and driven by a steam
engine or other motor. The action of the helice on the fluid material
is to force it upwards through the tube, but in order to ensure its ascent
out of the water to any desired height screw propellers are made to
rotate within the tube, or the air in the tube is exhausted by any of the
usual modes. The helical cutter or instrument thus constructed and

page_text: placed is drawn or urged against the bottom by a forward motion given
to the vessel in the usual way. The cylinder and helical cutter are made
of suitable steel or chilled iron.
And in order that my said Invention may be properly understood,
I now procced more particularly to set forth the system, mode, or manner
in or under which the same is or may be used or practically carried into
effect, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say:
A general design and arrangement of a vessel provided with the
improved dredging apparatus is shown at Figures 1, 2, and 3, Sheet 1
of the accompanying Drawings, of which Figure 1 is a longitudinal
section of the vessel showing the dredging apparatus as when engaged
in dredging operations.
Figure 2 is a plan of the same, in which the dredging apparatus is
shown raised to a horizontal position, this position being also shown
dotted at H, Figure 1.
Figure 3 is a transverse section of the vessel and part of the dredging
apparatus, which consists of a cutter or digger B formed of two helical
blades winding round an axis and rotating in the cylindrical chamber or
barrel L, which is connected to a tube A, and the latter is made of
suitable length to dredge to the maximum depth required. The shaft C
is driven by the geared wheels E and the steam engine E¹. The tube at
its upper end is formed with trunnions T, T, which work in bearings
and admit of the angle being varied to suit the depth, and also of raising
it out of the water when desired by the tackle G, Figure 1. The fluid
dredge is discharged through one of these trunnions, and in the opposite
trunnion is the bearing of the gear shaft. The helical blades B will
impel the fluid dredge upwards, but with a certain degree of rotatory
motion, which is however converted into direct upward motion by the
deflecting blades t, t, which also serve as arms to support the bearing
B' of the shaft C.
In order to elevate and force the fluid dredge the required height out
of the water (several kinds of rotatory pumps may be employed, but for
simplicity and non-liability to get out of order) a screw propeller of
suitable form, diameter, and pitch is preferred. An arrangement to
effect the purpose is shown in Figures 1 and 2 at D, where the tube 1s

page_text: enlarged to form a propeller chamber, and in which a two-bladed
propelier is shown at s with deflecting blades t above them, the arms
of which agam serve to carry a bearing for the shaft. When required
to elevate to a still greater height the diameter of the chamber and of
the propeller respectively is increased, or a second propeller chamber
is formed in the tube. When the deposit at the bottom or strata is
hard or very tenacious it becomes necessary that the cutter should
revolve more slowly; or when a considerable elevation is required to be
given to the fluid dredge, a different arrangement of the cutter and the
elevator from that above described is proposed to be made, viz., by
driving each of them at different speeds. This is effected by the mode
shown in Figure 4, where each has a separate shaft. The principal
shaft p, as before, drives the helical cutter. On the upper end of this
a spur wheel is placed, and on the upper end of the separate shaft c
which drives the screw elevator a pinion is placed of about one-thiru
the diameter of the wheel. The relative positions of the cylinder and
the chamber are modified to suit this, and the shaft of the cutter is
brought outside of and parallel to the tube by means of a slight bend
in it near the cylinder, all as shown at the said Figure 4, Sheet 1 of the
Drawings.
Figure 7 is an enlarged section of the cylinder above referred to
showing the helical cutter B and the deflecting blades t, and the bearing
of the shaft.
Figure 8 represents an enlarged section of the propeller chamber D
showing the screw propeller S.
Figure 9 shows an enlarged section of a modification of the helical
cutter tapering gradually to a point, and projecting outside the cylinder
so as to cut into and raise the material of the bottom in advance of the
cylinder when this may be desirable.
A third modification of the helical cutter is shown at Figure 10, where
the blades are shortened as much as possible to enable the apparatus to
operate the better on a tenacious mud or clay bottom, thus sacrificing
to some extent their impelling or elevating power.
Figure 11 shows a cutter of a design different from all of the others,
viz., in which a short cylinder or ring is formed or cast around the
blades which are also shortened, and it revolves with them in advance
of the fixed cylinder. The revolving cylinder is provided with a serrated
edge, which enables it to cut into the bottom.

page_text: In operating with the apparatus described in the preceding Specifi-
cation, the vessel is drawn forwards as in the ordinary dredging
apparatus by means of an anchor laid out in advance, the hawser of
which is wound in by the winch N placed in the bows, with another
similar anchor and hawser laid out at the stern to steady the vessel. The
dredging apparatus is then lowered by the tackle G, Figure 1, till the
cutter end of the cylinder touches the bottom, when the cutter is set
in motion and allowed to work its way gradually to the depth that will
yield the spoil or fluid dredge of the proper consistency or fluidity. As
a further appliance to facilitate the governing of the operation, a
trundle or roller O is fitted to the cylinder L, and travels in advance
of it on the bottom, as shown in Figure 5 and Figure 6. The depth to
which the cutter may dig, and the proportion of water admitted, are
controlled by this appliance, and may be regulated according to the
inclination of the tube by means of the adjusting screw e actuated from
the deck of the vessel.
On Sheet 2 of the annexed Drawings is represented a modification
of the mode of adjusting the length of the tube to the depth of water
at which the apparatus is required to work.
Figure 1 is a part longitudinal section, and Figure 2 is a part trans-
verse section, which show the tube made in two divisions, marked
respectively A and B, the upper one A being hung on trunnions as
before, but with a view only to the tube being raised out of the water
when required or when not at work, as shown at D, Figure 1, dotted.
When the apparatus is in operation the upper division of the tube lies
bedded in the well of the vessel in the position shown, and the angle
of it is never varied. The upper division of the tube A is bored out true
to receive the lower division B, which is turned on the outside to fit
easily into the former with a "stuffing box" y on the lower end of the
division A, which is thus adapted to slide up into A as in a telescope.
The sliding rods and chains shown at I and J lead over pulleys x, x, to
a winch E on deck, by which the tube may be shortened or elongated.
The driving gear F and steam engine F¹ are applied in the same manner
as with the apparatus shown on Sheet 1, excepting only that the shaft
K slides up through the eye of the wheel upon it in the degree or pro-
portion that the entire tube is shortened, as shown by the dotted pro-
jection upwards of the shaft at O, Figure 1.
C, Figures 1 and 2, shows a section and outside elevation of the cutter
and digger, and of the propeller chamber so arranged as that the latter

page_text: is immediately above the former. Figure 3 is an enlarged section of
the same in which a short helical cutter G is shown similar to that
on Sheet 1, Figure 10, with deflecting blades t, t, and bearing of the
shaft above. H is the screw propeller or elevator; w, w, are the
deflecting blades having the fixed bearing of the shaft situated between
them.
The operation of dredging with this apparatus is similar to that of
the apparatus shown on Sheet 1, except that the depth at which the
operation is carried on is regulated by clongating or shortening the tube
by the means shown instead of altering the angle of the tube as in the
latter. A regulating or adjusting trundle, as in Figures 5 and 6,
Shcet 1, may be used with it in like manner.
In place of employing a screw propeller for lifting the fluid dredge or
deposit other lifting apparatus or pumps may be used.
Having now described the nature of my said Invention, and the
manner in or under which the same may be used or practically carried
into effect, I would observe in conclusion that I make no claim to the
hull or barge in which the dredging apparatus is fixed; but what I do
consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent is,―
First. The general arrangement and combination of parts constituting
the dredging apparatus, as herein-before described and shown in the
accompanying two Sheets of Drawings, or the modification thereof
shown at Figure 4, Sheet 1.
Second. The use or employment of a helical or spiral cutter or digger
for the purpose of effecting dredging operations, as herein-before
described and shown in the accompanying Sheet of Drawings.
Third. The use or employment in combination with helical or spiral
cutters of a rotating screw propeller or other elevator for the purpose
of lifting the fluid dredge, as herein-before described and shown in the
accompanying Sheets of Drawings, or any mere modification thereof.
Fourth. The arrangement and construction of the revolving combined
cylinder and cutter with or without a serrated edge, as herein-before
described and shown at Figure 11, on Sheet 1 of the accompanying
Drawings.
Fifth. The employment of a trundle at the cylinder or lower end of
the dredger tube, as herein-before described and shown at Figures 5
and 6, Sheet 1 of the accompanying Drawings.

page_text: Sixth. The employment of a telescopic tube for the purpose of
adjusting the working depth of the helical or spiral cutter or digger,
as herein-before described and shown at Sheet 2 of the annexed
Drawings
In witness whereof, I, the said Henry Oliver Robinson, have here-
unto set my hand and seal, this Twenty-seventh day of January
One thousand eight hundred and sixty-nine.
HENRY OLIVER ROBINSON. (L.S.)