Year: 1887

page_text: Date of Application, 9th Sept., 1887
Complete Specification Left, 9th July, 1888
Complete Specification Accepted, 17th Aug., 1888
ADOLPH VOGT of Kiel in the Empire of Germany Civil Engineer do hereby
declare the nature of this Invention to be as follows:-
The object of my Invention is to provide in dredgers such an arrangement that the
work is much facilitated and the dredger as a whole is much more efficient than
hitherto. One of the chief objections to dredgers as hitherto arranged is owing to the
fact that the same vessels which perform the dredging have also to act as conveyers of
the spoil to a considerable height and vice versa. Hence all the buckets should be of
heavy construction on the one hand to fit them to act efficiently or to the best
advantage upon the matter to be removed whilst on the other hand when they are
acting as carriers or elevators merely they should be as light as possible. It will be
seen that with the ordinary arrangement it is impossible to reconcile these opposite
requirements with each other and that a mean between the two has to be taken thus
combining the defects of too great weight when the buckets are elevating and too
little weight firmness and rigidity when the buckets are acting on the material to be
removed. According to my Invention I provide an arrangement whereby I separate
the functions of dredgers proper and of carriers or elevators the buckets of the
dredgers proper operating simply as dredgers to remove the earth or other matter and
the buckets of the carriers or elevators receiving the spoil from the dredgers proper
and acting simply as carriers or elevators of the spoil to the place of discharge.
Another defect in ordinary dredgers is the smallness of the revolving drum round
which these cumberous and heavy buckets have to move; this is suspended and allows
the buckets to touch the ground for too short a time to properly penetrate the matter
to be removed and fill themselves therewith and the mouths of these buckets being
large and massive their brims naturally offer great resistance to the ground or material
into which they have to penetrate and if this ground or material be at all hard and
stiff they penetrate with the greatest difficulty and frequently come up empty or only
partially filled. It of course requires an enormous power to force a portion of a
bucket so suddenly into stiff ground or material as to enable it to fill itself and as this

page_text: cannot be effected without each time communicating a severe shock and vibration to
the whole dredging frame drum and driving gear and constant jerks to the bucket
chains links and bearings constant breakages necessitating repairs are the natural
consequence which cause a great loss of time.
This Invention is also designed to overcome this objection.
In carrying out my Invention I employ a large wheel or drum with three divisions
and fitted to rotate on an ordinary floating dredger Pontoon. The central division of
this wheel is raised or of a conical figure in cross section and on it are mounted saddle
shaped primary diggers or scoops which on the outside are shaped like ploughs,
enabling them to loosen the soil with the least possible resistance, their bottoms being
placed at such an angle to the axis of the wheel that on each scoop arriving at a
certain position during its upward movement its contents will fall out and pass
towards the two side divisions of the wheel over which side divisions pass large chains
of buckets to receive and transport upwards the material which has so fallen out on
each side from the diggers passing round the central division of the wheel.
The said wheel is centred and works in bearings fixed on the inner sides of a
stirrup-shaped frame suspended near its upper part by circular hollow projections
fitting into rings or bearings forming the upper part of hydraulic rams and being
situated in an opening at the end of the beams forming the ladder on which the
transport bucket chain ascends.
The hydraulic Cylinders of the said rams are hinged on to the pontoon at the sides
of the wheel and have fastened to them a frame which acts as a guide to the movement
of the rams.
By this arrangement the entire wheel works in hydraulically suspended bearings
and can be raised and lowered with great ease whenever circumstances demand it.
The stirrup frame is free to swing or oscillate on its centre or point of support
which is situated excentrically to, or at a point above, the centre of the wheel so that
the latter is enabled to swing backwards and yield when meeting with undue resistance
and to advance as soon as this obstacle is overcome.
The large wheel can be driven by toothed gearing of which a couple of toothed
wheels work into the teeth of another pair of wheels on the axle shaft that carries the
large wheel. These toothed wheels are concentric with the cylindrical projections of
the stirrup frame as their axles pass through those projections. The transmission of
power from the motor to these two wheels is preferably effected by means of a chain
which can be easily lengthened or shortened to suit the higher or lower position of the
wheel.
In lieu of toothed gearing on the large wheel, chain gearing may be employed in
which case two or more chains are passed round two large chain wheels (which are
fixed concentrically the large wheel) and round a couple of small chain wheels the
axles of which are arranged concentrically with the axes of the stirrup.
Instead of the large wheel hereinbefore described a similar wheel of the same or of
similar construction to that of the large wheel may be used having its centre division
provided with indentations into which the links of a loose chain of saddle shaped
diggers fit which chain of diggers passes round a second but lower drum so that the
diggers scrape the bank of earth in front of them whilst ascending. For ground or
matter not offering much resistance this arrangement is suitable but for heavy soil
or matter the large and heavy dredging wheel with scoops as hereinbefore described
is preferable because when revolving its momentum greatly facilitates the overcoming
of local difficulties.

page_text: I ADOLPH VOGT of Kiel in the Empire of Germany Civil 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:-
The object of my Invention is to provide in dredgers such an arrangement that the
work is much facilitated and the dredger as a whole is much more effectual than
hitherto.
Bucket ladder dredgers as hitherto arranged have failed to produce such satisfactory
results as might have been expected from the progress that has been lately made in
the construction of machine tools in general.
A careful examination of the defects has shown that in order to remedy the same
the machine must be constructed on the principles hereinafter described with a view to
obtaining the following results namely.
1st. Separation of the dredging work proper from that of transporting or carrying
away the spoil.
2nd. Avoidance as far as possible in working on different descriptions of hard soil
of the shocks to which the long heavy bucket chains with many links and the ladders
or side frames of the same are usually exposed.
3rd. A simultaneous and continuous action of the dredging apparatus on as large
an area of ground as possible with a view to employing the mechanical power to better
advantage.
4th. Rendering the carrying vessels or receptacles as light as possible in order
to enable the material to be elevated to such a height as to admit of its being
delivered by means of water directly on to the high banks of the canal in course of
excavation.
And in order that the said Invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed sheets of drawings the same letters of reference indicating
corresponding parts in all the corresponding figures.
Figure 1 of the accompanying drawings represents in side elevation a dredging
machine constructed according to this Invention.
Figure 2 represents the machine in end elevation and Figure 3 is a similar view
with the scoops and bucket chains removed. Figure 4 shows the machine in plan
under the same conditions as in Figure 3.
Figures 5 and 6 represent a sectional elevation and a plan illustrating the method of
working the dredger and the arrangement for removing the spoil.
Figures 7 and 8 illustrate in side and end elevation respectively a modification of
the construction as hereinafter described.
Figures 9 and 10 drawn to a larger scale represent the dredger buckets and the

page_text: method of attaching the same to the chains as employed with the arrangement
illustrated in Figures 7 and 8. Figure 11 represents in section also on a
larger scale the upper driving drum on top tumbler (A Figures 7 and 8) employed
with this arrangement.
Referring to Figures 1 to 6 A is a large wheel the periphery of which is divided
into three divisions namely a central portion A' Figures 3 and 4 and two side
portions A¹. The projecting middle part A of the periphery is raised or of a rounded
or conical figure in profile as indicated in Figure 3 presenting inclines on both sides
and is provided with saddle shaped primary diggers or scoops S as represented in
Figures 1 and 2 which on the outside are shaped like tines with a ploughing action
or of suitable form for scraping away the soil from the bank with the least
possible resistance their bottoms being placed at such an angle to the axis of the
wheel that on each scoop arriving at a certain position during its upward movements
its contents will fall and pass towards the two side divisions A¹ of the wheel.
These two lateral divisions A¹ of the circumference of the wheel carry two bucket
chains or Jacob's ladder elevators provided with buckets p so arranged as to receive
the spoil discharged from the scoops S and elevate it to the upper part of the
dredger.
The wheel A is centred and works in bearings æ in a strong stirrup shaped frame b
suspended near its upper part by two hollow studs n fitting in or connected to an
extension of a hydraulic ram or piston working in a cylinder c Figure capable of
turning or rocking fore and aft of the pontoon B on hinges m. To impart the requisite
steadiness to the structure one or more beams L Figures 1 and 4 are connected to the
studs n at one end and at the other end to hinges or pins at the upper part of the
framework of the dredger in an inclined position so as to form a species of bucket
ladder for the chains of buckets p. By this arrangement or combination of the
hydraulic ram and bucket ladder the stirrup shaped frame and wheel A are enabled
to swing or oscillate upon the studs n as a centre this centre being situated
eccentrically that is to say at a point above the centre of the wheel so that the latter
is enabled to swing backwards and yield when meeting undue resistance and to advance
as soon as the obstacle is overcome. The centre n can also be raised or lowered by
the action of the hydraulic rams c which are connected to a frame f which acts
as a guide to the rams and imparts additional strength or firmness to the structure
being connected to the pontoon by the hinges m so as to rock or oscillate with the
rams. In order to lessen the lateral strain on the legs or side pieces of the stirrup
shaped frame b the studs or centres on which the wheel A rotates may be made hollow
for the reception of a strong shaft a Figure 1 passing through the centre of the wheel
and uniting the two ends of the frame b. The guides may also be connected together
at their upper extremities by a horizontal piece f¹ as indicated in Figures 2 and 3.
Motion is imparted to the wheel A from a suitable steam engine or other motor on
the pontoon by means of two endless belts or chains T driving pulleys or sprocket
wheels Figures 1, 2, 3 and 4 fixed on two shafts working in the hollow studs n
hereinbefore referred to. Each of these shafts is provided with a pinion or toothed
wheel gearing with corresponding teeth a' on the wheel A. The length of the belts
or chains T can be adjusted to suit the different positions of the dredging wheel.
In lieu of the toothed wheels r driving the large wheel a chain wheel may he
employed in which case endless or pitch chains are passed round two large chain
wheels fixed concentrically with the large wheel and round a couple of small chain
wheels arranged to rotate on the axis of the joint connecting the frame b to the
bucket ladders L in the same manner as the wheel r.
The two chains of buckets p Figure 1 work on ordinary top tumblers or drums p
arranged at the upper part of the dredger and having a positive motion imparted to
them from the engine in a similar manner to the large wheel. The spoil carried up by
the buckets either slides down inclined shoots on to the banks of the canal or is
carried to the required distance by means of water in long conduits or tubes such as
the conduits R provided with adjustable supports was represented in Figures 5 and 6
for example.

page_text: The action of this dredger is as follows:-The pontoon is moored in front of the face
of the cutting and the large wheel A is lowered to the bottom of the canal or cutting
so that nearly one fourth of the scoops on its periphery are brought in contact with
the earth as represented in Figure 1. The pontoon is so arranged as to be capable of
turning on a central vertical axis formed by a post d fixed by screws or otherwise to
the bottom of the canal and the large wheel rotates and acts on the bank or face of
the cutting with the scoops S as the pontoon rotates on the centre post d. This com-
pound movement has the effect of causing each scoop to move in a diagonal line on
the face of the bank and the two motions are so regulated or combined as to enable
each scoop to fill itself in describing about one fourth of a complete revolution of the
wheel A.
The scoops of this improved dredger unlike the scoops of ordinary dredgers which
have to fill themselves whilst they are applied to a relatively small surface of the
cutting, are thus caused to scrape a very long surface and their mouths are enabled to
act under much more favourable conditions as regards the digging action and at the
same time the strain on the machinery is equalized owing to the number of scoops
that are always caused to act simultaneously on the face of the bank or cutting,
moreover owing to the large extent of surface that can be operated on at a time by
the employment of wheels of sufficient breadth a considerably larger number of cubic
feet of stuff can be dredged up or removed than would be possible with a dredger as
heretofore constructed.
A further advantage of the improved dredger results from the method of suspending
the large wheel on the frame b, oscillating on a centre above the wheel so that the
latter is free to yield when the scoops meet with excessive resistance and thus auto-
matically adjust the depth of the cuts taken by the scoops in accordance with the
nature of the ground. Moreover in consequence of this method of suspending the
wheel A the pressure on the scoops is never more than a small fraction of its weight
so that the horizontal motion of the dredger which is produced by means of mooring
chains K as illustrated in Figures 5 & 6 (which represent a sectional elevation and a
plan of a cutting in course of formation with the improved dredger) can be readily
regulated so that all injurious friction between the wheel and the bank is effectually
prevented.
When the scoops S are filled they empty themselves in succession on reaching a
certain level and discharge their contents on each side of the central raised part of
the wheel into the buckets or elevators p.
As these elevators are simply required to convey the spoil and are in no way exposed
even to the very slight shocks or jerks that may occur in working the improved
dredger they are enabled to be made much lighter and consequently much longer
without disadvantage and to carry the spoil to a considerably higher level (say 70
or 80 feet) than is possible with dredgers as heretofore constructed.
Instead of the large wheel herein before described a small wheel or drum may be
employed having its central division arranged to receive a chain of digging scoops
according to the modified arrangement illustrated in Figures 7 and 8. According to
this modification the dredger is provided with an endless chain of scoops S which work
over two wheels or drums A and a². The periphery of the upper drum A is of the
form or profile indicated in Figure 11 being similar to that of the large wheel A in
the arrangement hereinbefore described with reference to Figures 1 to 6 but the
lower drum a² simply acts as a bottom tumbler for the scoop chain S being carried by
the swinging frame b so as to be raised and lowered together with the upper drum by
means of the hydraulic apparatus c. Suitable hoisting gear y is also provided for
adjusting the angle at which the scoops are to work the mouth pieces of the said scoops
being made of a hoe or tine like shape as indicated in Figures 9 and 10 similarly to
the scoops on the large wheel A in the other arrangements. The arrangement firstly
hereinbefore described with reference to Figures 1 to 6 is preferable for working on
hard or difficult ground the second arrangement (Figures 7 to 10) being more suitable
for light or sandy soil the principle of action being substantially the same in both
cases,

page_text: 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. In a dredger arranged and operating as hereinbefore described and claimed the
arrangement of the scoops upon the rounded or inclined periphery of a wheel (A
Figures 1 to 6) or upon a scoop chain (S Figures 7 to 11) working on drums or
tumblers (A a) the said wheel or chain being employed in combination with a bucket
chain or Jacob's ladder elevator for carrying away the spoil discharged from the
scoops substantially as hereinbefore described with reference to the accompanying
drawings.
2. In a dredger suspending the wheel carrying the scoops or the bottom tumbler
of a chain of scoops on a support (b) oscillating on an axis above the axis of the
wheel and connected to stays or bucket ladders L and to hydraulic rams or hoisting
gear hinged to the dredging vessel with the object of imparting elasticity to the
action of the dredger scoops and enabling the position of the latter to be adjusted
substantially as herein before described with reference to the accompanying drawings.
3. The arrangement of dredging apparatus in which a regular and smooth action
is obtained by causing the scoops to work in a circular or other curve upon the face
of the cutting or bank to be removed the entire machine and vessel being caused to
rotate on a fixed vertical axis and the scoops being caused to discharge their contents
into a bucket chain or Jacob's ladder elevator substantially as herein before described
with reference to the accompanying drawings.
4. The arrangements and combinations of parts constituting the improved dredging
apparatus substantially as hereinbefore described and illustrated in the accompanying
drawings.