Improved Screw-dredger.
Year: 1894

page_text: Date of Application, 3rd Feb., 1894-Accepted, 7th Apr.,
1894
Improved Screw-dredger.
I, JOSEF HAAS, of Vienna III, Haupt Strasse 72, in the Empire of Austria,
Engineer, 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 dredger consisting essentially of a tube in
which a screw is arranged for transporting or conveying the material loosened or
excavated by the tube, or by a suitably formed part of such tube (so called cutter
head), or by the screw itself, through such tube to a discharge channel.
I will now describe my invention with reference to the accompanying drawings,
in which :-
Fig. 1 shows the improved screw dredger in elevation, the enclosing tube being
shown in section.
Fig. 2 & 3 show in side elevation and plan views respectively one of the bearings
for the screw dredger.
Fig. 4 & 5 are side and plan views of the cutter-head.
Fig. 6 & 7 show in side elevation and plan views, the arrangement of the dredger
on a boat, for dredging rivers, harbours, etc.
Fig. 8-10 show in elevation, plan and end views, the arrangement of the dredger
on trucks or portable platforms.
Fig. 11 shows a stationary arrangement for the dredger.
Fig. 11 & 11 are detail sectional views of Fig. 11 on a larger scale.
Fig. 12 & 13 are sections of different kinds of screws.
Fig. 14 shows a drilled-formed screw used as a substitute for the cutter-head.
Fig. 15 & 16 are detailed sectional views of Fig. 11.
Fig. 17-20 show different devices in elevation and plan views for raising the
platforms.
Fig. 2 2 & 3^ are end and sectional front elevation and plan respectively of
the driving, break and releasing mechanisms.
As seen in Fig. 1, this improved dredger consists of a tube M in which a
screw S is arranged, and at the lower end of which a cutter-head L is secured.
This cutter-head L has several arms a which are formed like a ploughshare
and the lower ends of which are attached to a boss or nave, in which the
spindles of the screw S rotates. The screw S extends to the boss & consequently
the inner edges of the arms a are correspondingly cut away & only form spoon-
like extensions of the tube M. By means of the collars K, the upper end of
the tube M is rotably mounted on a collar ring C consisting of two parts. A
cog wheel 7 is mounted on the tube M above the collar ring C; above such
wheel the discharge channel D with cylindrical frame D' is provided, such
channel being secured to frames G by stays w (Fig. 2B & 3). The screw S
extends through the tube M to the channel D & likewise carries on its spindle
a bevel-wheel Z, so that by suitable gearing the screw and the tube can be
rotated (Figs. 3, 2A, 2B). Both the screw and tube may be rotated in the same
or in reverse directions. It is preferable that they rotate in the same direction
when it is desired to also raise dredging material of small grain, and in the reverse
direction when only a coarser or rougher material is to be lifted, in such manner,
that by the reverse rotation, an assortment of the smaller and lighter particles
from the larger and heavier ones is to be effected in the tube. In the latter case
the separation of the smaller particles would be considerably facilitated and assisted

page_text: if the screw threads were meshed or perforated like a sieve, instead of being solid,
in order that the small particles may fall through the holes. On account of the
reverse rotation, the material will be constantly dashed together, and the screw
will only work to raise the excavated material according to the difference in
velocity of the two rotations respectively.
The arms a, however, must be so placed that they convey all the excavated
material to the screw.
The operation of the dredger is as follows:-
The cutter-head L rotates with the tube M and on reaching the ground enters
same by means of its arms a and forces the loosened material into the openings or
interstices between the cutter-head owing to the peculiar plough-share like form
of such arms to the centre of the cutter-head. Inside the cutter-head is the
screw S whose lower threads are thus always covered with excavated material.
The tube rotates quicker than the screw S, so that the earth on the bottom thread
of the latter is easily pressed forward, i.e. the screw does not immediately raise all
the material as it is excavated. As the screw rotates in the sense of its thread the
material on its lowest thread is constantly raised and finally discharged into the
channel D.
The threads of the screw may be made integral with the tube M and allow the
spindles to pass through same; or the screw S may be secured to the walls of
the tube, and in like manner allow the passage of the spindles (Fig. 11B & 13).
In these cases the cutter-head is secured to the end of the spindle s.
If the screw
and tube be made of one piece, the spindle s may be dispensed with, and the cutter-
head secured to the tube M as previously shown. A section of such a tube is
shown in Fig. 12. The threads of the screw may also be formed like a drill
projecting beyond the end of the tube, in which case the cutter-head L also would
be dispensed with Fig. 14.
In either case the screw employed for raising or transporting dredged or
excavated material may have one or several threads or worms.
This screw dredger may be employed either for dredging rivers, harbours, or the
like, or for any kind of land excavations.
The
The dredger represented by Figs. 6 & 7, shows two series or rows of such
tubular dredgers, arranged at the head and stern of a boat, in such manner,
that the front row consists of shorter tubes M than the row at the stern.
depth of dredging is equal to the vertical lengths of both cutter-heads, if the
surface is even or regular. The arrangement of the rows of tubes being the
same, it will only be necessary to describe the operation and arrangement of
one row.
The dredger tubes M are mounted on a platform P in such manner that each
tube may be operated quite independently of the others. Each tube M rests in
the bearings L' L' (Fig. 3) with the aforedescribed collar ring C provided with
two pivots bb for this purpose.
Standards G G (Figs. 2 2B, & 3) are arranged on both sides of the collar-ring C,
and form the bearing for the driving mechanism. This driving mechanism (Fig. 2,
3, 2A, 2B, & 3) consists of the cog-wheel Z' loosely mounted on the pivot of the
collar-ring C and engaging with cog-wheel mounted with wheel or pinion Za
on a shaft Win said frame or standard G. Said pinion Z³ engages with the
bevelled wheel Z of the tube M and thus rotates the latter. The wheel Z²
engages with a wheel Z driving the shaft W2 and the pinion Z mounted on
same. This pinion Z engages the wheel Z of the spindle, and thus rotates the
latter. As the driving mechanism of the tube M and screw S is provided in
the standard G, and is derived from the wheel Z resting loosely on the pivot of
the collar-ring, the tube M may be fixed or set at any desired angle, without
interfering with the operation of the driving mechanism. Behind each tube a
driving shaft Ws driven from the main shaft W, is mounted, and by means of
wheel Z, the wheel Z' is rotated. In order that the tube M may be inclined
or tilted as desired, a cogged wheel R is securely mounted on the second

page_text: pivot 6 (Fig. 2B & 3A), which wheel engages with the cog-wheel R' adapted to
be slided on shaft W3; the wheel R has also 2 pawls p (Fig. 2), in order
that the tube may be fixed at any desired angle, either in a forward or backward
position.
The
When the shaft Ws is driven, the wheel R rotates until the wheel R' is disengaged;
it is therefore possible to raise the tube to any desired angle, above the water.
sinking of the tube M to the ground is effected by means of a brake device B
(Fig. 2 & 34), after the pawls p have been disengaged or released.
From the main shaft W, which may be driven by any suitable engine, the
shafts W³, and from these each tube M and screw S, are set in motion by the
aforedescribed driving mechanism. The dredging operation then takes place as
previously mentioned.
The advancing movement of the dredging boat is effected in the usual manner,
but such movement must be sufficiently great, to correspond to the engagement of
the cutter-heads with the ground. If a tube M during dredging comes in contact
with an obstacle-for instance, a block of stone-which it cannot pass, such tube
turns on the pivots bb, of the collar-ring C, rises, dredges over this obstacle, and,
after same is passed, sinks to the ground again. If the cutter-head comes in
contact with a still greater obstacle so that it cannot rotate, its belt will creep,
whereas the remaining tubes will continue to operate.
The material raised by the screw S falls into channels D. When it is required
to sort or separate the dredged material, the discharge channels (which are
perforated or meshed according to the size of the material desired) are conducted
over other channels which carry away the separated material, as shown, for instance,
in Figs. 6-10. In dredging river deposits, the dredged material, may, for
instance, be sorted in sand and rubble-stone, the latter being afterwards further
separated or assorted.
The dredger shown in Figs. 8-10 for excavating dry material consists only of
one row of dredger tubes M, arranged as with the dredger above described. All
the tubes are mounted on a platform P mounted on four trucks.
The dredgers may all be driven by means of one engine mounted either on one
truck or platform, or an engine may be mounted on each truck for operating a
corresponding number of tubes M. Sorting devices and disintegrators may also be
arranged on such platform as for dredging in water, and the excavated material
may be discharged at either one or both sides of the platform.
Both with this dredger for dredging in water and for earth excavations, slopes,
declivities, or escarpments may be dredged or excavated in accordance with their
angles of inclination. This is effected as follows:
If, for instance, the outer tubes are to excavate the slope, the outer tube at each
side (Fig. 8 & 10) is arranged at an angle corresponding to the angle of inclination
of the slope. The next inner tube is arranged at a somewhat greater angle than
the first, and so on till they cover the full width of the slope. This arrangement
of the tubes will be seen from the dotted lines in Fig. 10. To prevent the
excavation being uneven or step-like, spikes or teeth may be arranged on the
periphery of the tubes M in order that any unloosened earth may be torn up and
caused to fall down to the next lower tube (cutter-head), by which it is raised.
For effecting a regular excavation the spikes may also be provided on tubes
operating in a vertical position.
In the arrangement shown in Figs. 11 & 11^, the tube M dredges or excavates
at a fixed or constant angle of inclination. If it be required to excavate deeper
with this dredger, the tube M is arranged with flanges, so that it may be extended
or lengthened by inserting the required number of connecting pipes between the
pipes M & M² (Fig. 114); the threads of the screw need not extend through the
inserted tubes. The spindle s may be likewise lengthened or extended by inserted
parts (Fig. 11^).
If the screw S is connected with the walls of the tube in this arrangement and
thus rotates the same, the cutter-head is securely attached to the spindle s,

page_text: Fig. 11; the upper end of the spindle bears against a frame K (Fig. 16) on
the hub of which the bush or collar c is supported. This extensible tube may
however be so arranged that the angle of inclination can be altered, as in
Figs. 6-10; the cutter-head may likewise be dispensed with, and screws of the
kind shown in Figs. 14 & 11 employed.
The platform P carrying the dredger tubes may be arranged stationary, whether
the dredger be used for dredging in water or for land excavations, as shown, for
instance, in Figs. 6-10; or, for raising and lowering the platform, same may be
provided in well known manner with rack 28, & pinion » (Fig. 17 & 18) or with
worm gearing operating a screw spindle g, (Fig. 19 & 20).
With this dredger and suitable extensions of the discharge channels, the
material may be discharged over the sides of the boat or directly into dams.
By
employing correspondingly larger tubes, drains may also be excavated, in fact,
this dredger may be employed for any kind of excavations or dredging.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. An improved screw-dredger with cutter-head at its lower end, in which a
screw S with one or more threads is rotably arranged in a tube M carrying at
its lower end a cutter-head L and rotating more rapidly than the screw S the
loosened material being conducted to and raised by the screw on account of its
rotary velocity being different from that of the cutter-head, substantially as
-described and shown in the drawings.
2. A dredger of the kind described in Claim 1 in which a screw S is connected
with a tube, M within which screw a spindle s rotates carrying at its lower end a
-cutter-head L the screw and tube thus rotating simultaneously round the spindle s
with a velocity different from that of the cutter-head, substantially as described
and shown in the drawings.
3. In a dredger of the kind described in Claims 1 & 2, the arrangement of
-same on a stationary or adjustable platform by means of a collar ring C loosely
mounted on pivots bb the gearing wheels being mounted in a frame G of such ring
so that the motion of the main shaft W is transmitted to the shaft W³ of each
tube M and from a wheel Z' mounted loosely on pivot b to the wheels Z2 and 75
and through these to the tube and screw, such arrangement enabling (by means of
a wheel R loosely mounted on the secondary shaft Ws driving the wheel R mounted
on pivot 6) each tube being raised and lowered without being disengaged from the
wheels Zand, by means of the secondary shaft W³, put into and out of operation
independently of each other, substantially as described and shown in the drawings.
4. In a dredger of the kind described in Claims 1 and 2, the arrangement of
spikes or teeth on the tubes M and cutter-heads L for tearing up unloosened earth
and causing same to fall under the tubes, substantially as described and shown in
the drawings.
5. In a dredger of the kind described in foregoing claims, the arrangement of
such dredger on a stationary or adjustable platform in one or several rows, in such
manner that each succeeding row consists of longer tubes than the preceding one,
which dredger may be employed for dredging in dry or wet places, and is provided
with a platform for each individual tube or for each series of tubes, the depth of
-dredging or excavating being regulated by adjusting the tubes either individually
-or in series as required, substantially as described and shown in the drawings.
Dated this 3rd day of February 1001
E. P. ALEXANDER & SON,
Fels. Chartered Inst. Patent Agents,
19, Southampton Buildings, London, W.C.,
For the Applicant.
E. P. ALEXANDER & SON,
Fels. Chartered Inst. Patent Agents,
19, Southampton Buildings, London, W.C.,
For the Applicant.