Year: 1895

page_text: I, PHILIPPE JEAN BUNAU-VARILLA of No. 21 Boulevard Poissonnière, Paris
in the Republic of France, Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention relates to certain improvements in dredgers whereby I am enabled
to dispense with the chains usually employed for obtaining forward and backward
movement of the dredger.
I am also enabled to dispense with the necessity of any anchorage or point of
support beyond the dredger and also to avoid the use of anchors, which are the
cause of a serious loss of time entailed by casting and hauling them up.
My invention consists in providing means whereby the dredger can be caused to
advance or recede or turn on its axis (système de papillonnage) to any desired
extent.
In carrying out my invention I propose to form a well within the main axis of
the dredger and to insert in this well a shaft, said shaft passing through the dredger
and reaching to the bottom of the river, canal, dock or harbour.
I also form a second well containing a similar shaft in a line at right angles or
eccentric to the main axis of the dredger where it passes through the first shaft.
These shafts may be made of metal or of wood in which latter case they are
provided at their lower extremnities with a pointed metallic shoe, and are 80
constructed as to be capable of being raised and lowered by any suitable device.
To effect a forward (or backward) motion of the dredger I proceed in the
following manner :-
The dredger being so situated that its main axis makes a definite angle with the
direction in which it is proposed to advance, the eccentric or second shaft is lowered
until it reaches the river bottom or bed. The central shaft is then raised the
dredger being thus free to turn on its eccentric shaft. This it is caused to do by
means of one or more helices or screws having horizontal axes arranged at right
angles to the axis of the dredger and to be worked by an independent motor or
from the principal source of power.
The dredger is in this manner caused to turn on its new or eccentric axis until
the central shaft reaches the desired line of advance when this latter shaft is
lowered and the eccentric shaft raised, the dredger being now in position for a
further movement; the helix or screw is again set in motion and the dredger
caused to turn in a reverse direction upon this central shaft. The operation being
repeated, the dredger is caused to advance or retire or if continued in one direction
to turn to any desired angle.
This method permits of complete control over the various parts of the dredger
by means of electric motors one or more of which may if desired, be placed
directly over the axis of the helix or screw to impart movement thereto; the
change of motion at each alteration in position of the dredger is consequently
extremely easy.
And further, my improved dredger can be used in shallow or narrow waters or
where the banks are of a shelving nature.
Dated this Second day of August 1895.

page_text: -
Improvements in Dredgers.
I, Philippe JEAN BUNAU-VARILLA, of No. 21 Boulevard Poissonnière, Paris,
in the Republic of France, 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 certain improvements in dredgers whereby I am enabled
to dispense with the chains usually employed for obtaining forward and backward
movement of the dredger. I am also enabled to dispense with the necessity of
any anchorage or point of support beyond the dredger, and also to avoid the use
of anchors, which are the cause of a serious loss of time entailed by casting and
hauling them up.
My invention consists in providing means whereby the dredger can be caused to
advance or recede or turn on its axis or centre line-(système de papillonage)-to
any desired extent.
Upon the accompanying drawings,—
Figure 1 is a plan of my improved dredger, and
Figures 2, 3, 4, and 5 are plans on a reduced scale shewing the dredger in
successive positions of working.
In carrying out my invention I propose to form a well p upon the centre line or
'main axis of the dredger and to insert in this well a shaft extending through the
dredger to the bottom of the river, canal, dock or harbour. A second well o
containing a similar shaft is formed in a line at right angles, or eccentric to the
main axis of the dredger where it passes through the well p.
These shafts may be made either of metal, or of wood, in which latter case they
are provided at their lower extremities with pointed metallic shoes, and are so
constructed as to be capable of being raised and lowered by any suitable device.
The forward or backward movement of the dredger is effected in the following
manner :-
The dredger being so placed that its main axis makes a definite angle with the
direction in which it is desired to advance, the shaft in the well o is lowered until
it reaches the bottom or bed of the river. The shaft in the central well p being
then raised, the dredger is free to turn on the shaft in the eccentrically situated
well o.
This motion is imparted to the dredger by means of one or more helices
or screws a, b, mounted on horizontal axes arranged at right angles to the main
axis of the dredger, and worked either by an independent motor, or by power
transmitted from the principal motor.
In this manner the dredger is caused to pivot on its eccentric axis o until the
shaft in the central well p comes directly over the selected line of advance, when
this latter shaft is lowered and the eccentrically located shaft raised, the dredger
being then ready to take up a new position; the helix or screw is again set in
motion and the dredger caused to pivot in a reverse direction upon the shaft in the
central well p. The operation above described being repeated the dredger is
caused to advance or retire, or if continued in one direction, to turn to any desired
angle.
The foregoing arrangement and method of working enable complete control to
be exercised over the various parts of the dredger by means of electro-motors,
one or more of which may, if desired, be placed directly over the axis of the helix
or screw to impart motion thereto, the change of motion at each alternation in
position of the dredger being consequently greatly facilitated. The construction
described also allows the improved dredger to be advantageously employed in
narrow or shallow waters, or in channels where the banks are of a shelving nature.

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. A method of, and arrangement for propelling and working dredgers from side
to side without chains or anchors, consisting in the alternate use of two wells
provided with separate shafts as pivots, one well p situate on the centre line or
main axis of the dredger, and the other, o, outside the said axis; and in the
propulsion of the dredger around one or other of said pivots by means of one or
more helices or screws a, b, having their shafts placed at right angles to the centre
line of the dredger, said helices being operated directly by a mechanical or
electrical motor, or by power transmitted from the principal driving machine,
substantially as described.