Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Dredger
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1 The invention relates to a dredger havin~ a floatlng body
on which ~he lifting mechanism featuring a restraining wlnch
for a grab suspended on ropes is mounted.
Such dredgers are well known, which ~re employed to reclaim
sand and gravel rrom deep/large depressions. Clamp ~hell grabs
are used for dred~ing, whereby the opening and closing oper~tior
is either effected with the aid of ropes or e~feeted through an
hydraulic mechanism. The grab is suspended on a travelling
crab, which if3 desi~ned to be self-propelled, or which reatures
a rope drive. A liftine ~echanism for raising and lowering or
the grab i8 arranged on the travelling crab, being driven by
a rope winch.
Furthermore, dredgers are also known for which a lu~ing ~ib
and a lifting mechanism for a grab arranged on a ~ib are
mounted. Such drrdgers are primarily used tor more limited
output3/capacities and for ~pot~corlcentrated dredglng.
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The di~advanta~e Or these known dredgers exists in the fact that
during winching/lifting operations q relatively laree dead
load is placed upon the lifting mechanis~, since the grab ~P
constitutes about a third of the load to be lifted. As a resul~f
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1 a high consumption of energy is needed during lifting and the
lifting mechanism has to therefore be of a corresponding slze/
sturdy proportions~
It is the objective of the invention to provide for the ~reRtest
possible lifting cspacity~range in respect to the welght of the 8rab
during the raising Or the laad.
Thi~ task i8 resolved according to the invention by the ~act
that the grab i~ connected with a counter-weight via a rope
in a contrary lifting and lowering motion.
; 10 Further advantageous embodiments Or the invention are provided
for in claims 2 to lO.
; The invention has the distinct advantage that the lifting
¦ mechanism can be designed for a more limited loading ~i.e.
; ¦ ~reater efficiency)~which is of considerable importsnce,
p~rticularly, for large lifting distances, which, for such
dredgers, amount up to 100 metres.
The invention is explsined in deta~l in the following description
with the aid examples depicted in the drawings.
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They show:
Fig.l such a dred~er in olevation,
Fig.2 a plan view ~f Fig.l,
--- ~ f~ r ~mbodiment of such a ~Ir~L~r in
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1 simplified representation in elevation,
Fig.4 a plan'view of Fig~3
~ig.5 a further embodiment of the dredger in simpllfied
representation in elevation,
5 ' Fig.6 a plan view of Fig 5,
Fig.7 an additional embodiment in elevation,
Fig.a a plan view of Fig.7~
Fig.9 a furtl-er embodiment of the dredger in elevation,
Fig.10 a plan view of Fig.9,
10Fig.11 a dredger having a luffing jib in elevation and,
~ig.12 a further embodiment of the dredger in ~levation.
~he dredger depicted has a floating body 1, on which various
¦ structures are mounted, i.e. a cross beam 3 i3 supported on
girders 2, on which a traversing arm 4 is arranged for a
travelling crab 5. The travelling crab 5 is provlded with a
li~`ting mechanism 6, which has a restraining winch 7. A grab 8
is suspended on tha restraining winch 7, by which the grab ~ can
be raised or lowered through n rope 9.
A rope 10 is wound on the restraining winch 7 in a
2Q contra-d~rection and is guided at one of the ends of ~e cross
supports
beanl 3over a derlecting roller~pulley 11 and~a counter-wei~ht 12
where upon the rope 10 is guid~dover a return roller~pulley 13
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1 on the counter-weight 12 to an anchQrage 14 on the cros6 beam 3.
The heavier grab 8, heavier by approx. 20% in respect to the
during liftin8
counter-weight lZ is counterbalanced/by the counter-weight 12
which lower~falls at the sane time, and, conversely, only
limited braking forces act upon the lifting mechanism 6 during
the grab loweringoperation. On depositing the grab 8 on the bed/
bottorn of the ~ea, lake or similar, the lifting gear brakes
are closed, so that the grab can operate under its full weight
without being balanced. -
In the embodiment sho~n,an additional winding/winching faceis provided on the restraining winch 7 for the ropa ~0. One
can also arrange the rope 10 for the restraining winch 7 ~uch
directly
that the rope 10 wraps itself~on to the restraining winch 7
as it unwinds during the lowering of the grab 8.
Dy this design and arrangement of tbe counter-welght 12 the
¦ drive 15 even enables simpliricatlon of the denign to be
¦ effected for the travelling crab 5, whereby this drive in
arranged at the oppoBite end of the cros6 beam 3 in relstion
to the deflecting roller~pulley 11. The drive is efrected via
a rope 16, whereby a tensional force is produced during
movement in the direction towards the crab drive unit 15,
whiist in the opposite direction,the travelling crab 5 is
drawn away from the counter-weight and effect~ A braking ~ction
on the drive 15.
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; With the embodiment depicted in figures 3 and 4 the 8rab 8 i~
counterbalanced directly with the c~un~er~weight 12, by which
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1 the rope 10 is attached vla an additional deflectin~ rollertpulley 17
on the traYelling crab 5 to the grab 8. This arrangement can be used
without further ado for light-dredgeable material.
With the embodiment in accordance with figure~ 5 and 6 the travelling crab 5
iB provided with its own drive, for which the rope 10 is deflected via two
additional deflecting ro}lers/pulleys 18l 19 in each case at the end of the
cross beam 3 and is anchored to the other side Or the travelling crab 5.
The embodiment depicted in figure 7 and 8 i6 suitable for a four-rope grab
operation, whereby a furthel closing winch 20 is arranged on the travelling
crab 5 next to the restraining winch 7. The rope 10 for the counter-wei~ht
12 is arranged to the restraining winch 7.
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In addition, figures 9 and 10 show an embodiment, ~or which the counter-
weight 12 is separated~divide~ for hydraulic ~rab operation on a four rope
winch, and the respective part-welght is arranged to the restraining winch 7
or to the closing winch 20. In this case, the drive provided for the
travelling crab 5 can be retained/utilized in the design.
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For the embodiment for a dredKer represented in fig.ll a luffing jib 22
is mounted on a ~loating body 1, which operates in conjunction with a
chute~hopper 21. By a steep positioning of this jib 22 the grab 8 ,
suspended from the jib can be lowered -through the floating body 1 into the
water. ~he raising and lowering Or the grab 8 is effected via a rope 9 and
a lifting mechanism 6 with the restraining winch 7. Laterally from the
lifting mechanism 6 is fixed a support 23 on the rloating body 1, which has
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l ¦ a deflectin~ wheel/pulley 24. From this support 23 is suspended , by meann
Or a rope lO, a eounter-weight having e return roller/pullay 13, the rope beln
guided over this deflecting roller/pulley 24 and over another roiler/
pulley 25 on th~ most furthest end of the luffing jib 22 to the grab 8.
With this arrangement the rope 10 can be guided directly to the winch 7 and
be wound in a counter direction to the movement of the grab.
With the f~rther embodiment depicted in fig.l2 the counter-weight 12 i8
suspended directly from the lifting mechanism 6, whereby the rope lO of the
¦ counter-weight is wound on to the winch 7 in the manner illustrated.
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