provements in Dredging Apparatus.
Year: 1894

page_text: COMPLETE SPECIFICATION
Improvements in Dredging Apparatus.
I JOHN CHARLES LANG of 10 Burnfield Terrace, Liskeard, Contractor, do
hereby declare the nature of this invention, and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:-
This invention relates to an improved dredging apparatus intended to provide
a means for scraping sand, mud and the like from water beds, in a more effective
and expeditious manner than has hitherto been done.
The mechanism I employ consists of a box like scraper or scoop mounted on
the end of a frame and drawn along the bed, scraping up the mud or sand.
This scraper is carried by a steam derrick crane with pulleys at the end and
middle of the gib, which pass ropes connected respectively to the rear end of
scraper frame and to the front of the scoop. Two pulling or winding barrels
are employed to work these lines.
A snatch block is employed fitted to the bottom or base of the crane, over
the pulley of which the second rope is passed when the scraper is in operation.
In order that the invention may be more clearly understood, reference is had to
the accompanying two sheets of drawings, in which
Fig. 1 shows the crane and the scraper ready for use, Fig. 2 shows it in operation
and Fig. 3 discharging its contents into a barge,
Fig. 4 is a plan and Figs. 5 & 6 are respectively a side and an end elevation of
the scraper.
The crane is similar in construction to those commonly in use, having a standard A
At the
and gib B carried on the bed plate C and supported in the usual manner.
end of the gib a pulley D is fitted and at about the middle a second pulley E over
which pulleys the wire ropes and e pass. The rope d is connected to the pulling
or winding barrel D', and e to the barrel E' fixed at the lower part of the crane
and revolved in the ordinary manner, winding up or paying out the rope. The
rope d passes also over the pulley at the top of the standard, aud e may instead
of passing direct from the barrel E¹ to the pulley E be taken over a pulley at the
top of the standard and thence to E as shown in dotted lines in Fig. 1.
The scraper Figs. 4, 5 and 6 is formed with a long frame F on one end of which
the scoop F is fitted, the scoop being of box form with open end, and having a
central rib or division f to give it greater strength forming two compartments, which
when used are filled by the sand or mud. As this scraper is drawn along the water
bed in a sloping position the scoop being at the front, the latter will scrape the
upper surface of the bed and carry the material away.
Chains or bridles and are fitted to the ends of the scraper to which the
ropes d and e are connected.
The apparatus is worked as follows:-
The scraper is let down vertically into the water by the rope d as shown in
Fig. 1 until it touches the bottom, the rope e also being paid out to permit
of this. The upper end is lowered until it takes up the position shown in
dotted lines in Fig. 1. It is then ready to be pulled in or dragged along the
bottom. To effect this, the rope e is drawn in at a short distance above the
water by a man by means of a rope e connected to e by a ring. The rope e is then
attached to the snatch block G which works centrally with the crane.
One being drawn in, the scraper will be dragged along the bottom at the
required angle and filled with the material on the surface of the bed. The

page_text: scraper is then raised to a horizontal position, as shown in dotted lines in Fig. 2
by releasing the rope e from the snatch block, and winding up both d and e
until the scraper is at the required level above the water. The material raised is
then emptied into the barge H (Fig. 3) or other suitable receptacle, by releasing
the rope e.
The scraper is now ready for the next operation, and is lowered again
as above described.
An alternative way of working is to reverse scraper, attaching rope
d to
chain and rope e to f¹. The snatch block is then secured to a mooring fixed
in advance of area to be dredged; it will thus be seen that the scraper can be
worked inwards or outwards as may be necessary.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. In a dredging apparatus the combination with a crane or like machine
having two winding drums with ropes, and two pulleys on the gib over which
the ropes pass, of a scraper, to the ends of which the ropes are attached, held
and dragged along the bed in a slanting position, substantially as and for the
purposes specified.
2. In a dredging apparatus the combination with a crane or other machine,
having two gib pulleys, ropes and winding drums, and a scraper attached to the
ropes at each end, of a snatch block fastened at the lower part of the crane or
to a mooring fixed in advance of area to be dredged, over which the palley rope
is drawn when the scraper is to be operated substantially as described and
shown and for the purposes specified.
3. The improved dredging apparatus, comprising a crane or other machine with
gib pulleys, standard pulley, winding drums and ropes and a snatch block and
a scraper carried by the ropes, constructed and operated substantially in the
manner described and for the purposes specified.
Dated this 31st day of July 1894
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.
GEO. H. RAYNER,
37, Chancery Lane, London, Agent for the Applicant.