Improvements in Caissons.
Year: 1892

page_text: Date of Application (in United Kingdom), 7th Sept., 1892
Complete Specification Left, 6th June, 1893-Accepted, 8th July, 1893
PROVISIONAL SPECIFICATION.
Improvements in Caissons.
I, JOHN FRANCIS O'ROURKE, Civil Engineer, of 22, William Street, New
York City, United States of America, do hereby declare the nature of this
invention to be as follows:-
My invention relates to improvements in caissons, such as are used in dredging
and preparing under-water foundations and structures, and the object of my
invention is to produce a caisson that has the advantages of the economy and
rapidity of work of the open caisson during the sinking of the same, while there are
no difficulties that prevent the excavation from being uniformly performed by
dredging and which when that method is interfered with by boulders or the solid
rock rising abruptly under one part of the bottom or from any other cause may be
casily converted by the introduction of a bell or its equivalent into a pneumatic
caisson having suitable means of ingress and egress for men and materials, so that the
caisson will have all the advantages of both the open and pneumatic caissons and
may be easily converted from one to the other. To this end my invention consists
in a convertible caisson, the construction of which will be hereinafter described.
The caisson is of the ordinary open kind having an inclined lower edge which
enables it to be driven down through the mud, silt, sand, and gravel, beneath the
water, and may be made in any suitable way and may be built up in sections in the
ordinary manner so as to make it of the necessary height. The caisson is adapted
to be used in the ordinary way as an open caisson and when it is to be converted
into a pneumatic caisson a roof or bell is used which is adapted to be lowered down
into the open caisson and has a depending flange which extends parallel with the
inner wall of the open caisson. The joint between the roof or bell and the open
caisson may be packed in any convenient way and I will here describe two
arrangements for the purpose. According to one arrangement, the flange of the
roof or bell is provided at intervals with supporting cleats through which extend:
bolts whose outer ends are received in sockets in the wall of the caisson, the inner
ends of the bolts being threaded and provided with adjusting nuts between which
and the cleats a suitable packing is inserted. Upon the inner ends of the bolts bear
screws carried in lugs, by slacking which the bolts may be quickly loosened when.
desired. Hydraulic presses supplied with power from above will be used whenever
it is desired to lower the bell and shaft without air within them. A packing is
placed at the lower edge of the flange of the roof or bell, between it and the
In the
adjacent wall of the open caisson, which is inclined inward at this point.
preferred form of packing however, between the flange and the wall are placed
expansible tubes which are connected with pipes adapted to connect with the
mechanism for supplying air to the dredging chamber or the tubes may be inflated
in any other way so as to effect a perfectly tight joint. The caisson may be:
provided with a number of chambers formed by partitions which terminate at their
lower ends in edges adapted to sink readily through the material beneath the water,
and the chambers formed between the partitions of the caisson have dredging

page_text: passages opening upward through the caisson. These passages may be closed by
bells or roofs which are similar to the bell or roof described above and opening
upward from these bells are shafts which serve as working shafts in the manner
already described and are provided with suitable locks at their lower or upper ends.
Three chambers may for example be provided, two of them arranged to be used as
pneumatic chambers, the bells being fastened in place above them and the other
chamber and its passage serving the purpose of an ordinary open caisson.
be seen that the arrangement described provides for using one or more chambers as
open caissons and one or more as pneumatic caissons, as circumstances require.
It will
The apparatus is used in the following way: The open caisson is sunk downward
through the mud, silt, sand, and gravel, by dredging from within and beneath it and
nsed as long as it conveniently can be as an open caisson and when the more solid
bottom is reached or the caisson strikes an obstruction the bell or bells as the case
may be and the shafts are lowered downward into the caisson and secured firmly in
place in the manner described, or by any other means that will properly connect the
bell or roof to the caisson. Compressed air is then forced downward into the
dredging chamber or chambers, thus forcing out the water and leaving the chamber
in condition for the men to work within it and the men and materials may be
lowered in the ordinary way through a passage provided for the purpose. When
the desired level is reached and all the work necessary to complete in air is done,
the men are withdrawn, the compressed air removed, the bell removed, and the
concrete lowered through the water and filled up within the open caisson to a point
where it is desirable to pump out the water and complete the structure. There
may be cases where only the sinking of the caisson is desired, as in the case of
sinking shafts.
The upper part of the caisson may be made in detachable sections like the sides
of an ordinary floating caisson for convenience in removal after the masonry is
built. I do not claim the construction of either the open caisson or the bell as a
part of my invention, as open caissons and diving bells have long been used
individually but the combination described and the convertible feature set forth
above is believed to be new.
Dated this 7th day of September 1892.
J. F. ROURKE,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.
COMPLETE SPECIFICATION.
Improvements in Caissons.
I, JOHN FRANCIS O'ROURKE, Civil Engineer, of 22, William Street, New York
City, United States of America, 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 :-
My invention relates to improvements in caissons, such as are used in dredging
and preparing under-water foundations and structures, and the object of my
invention is to produce a caisson that has the advantages of the economy and
rapidity of work of the open caisson during the sinking of the same, while there are
no difficulties that prevent the excavation from being uniformly performed by
dredging, and which, when that method is interfered with by boulders or the solid
rock rising abruptly under one part of the bottom, or from any other cause, may be
easily converted, by the introduction of a bell or its equivalent, into a pneumatic
caisson having suitable means of ingress and egress for men and materials, so that
the caisson will have all the advantages of both the open and pneumatic caissons
and may be easily converted from one to the other.
To this end my invention consists in a convertible caisson, the construction of
which will be hereinafter described and claimed,

page_text: Reference is to be had to the accompanying drawings, forming a part of this
Specification, in which similar figures of reference indicate corresponding parts in
all the views.
Figure 1 is a central vertical section of a caisson embodying my invention
shewing it provided with a single dredging chamber and with the bell or roor
secured in position in the open caisson;
Figure 2 is a plan view of the caisson shown in Figure 1
1 3
Figure 3 is an enlarged detail sectional view of one method of packing the joint
between the roof or bell and the sides of the open caisson;
Figure 4 is a central vertical section of a caisson embodying my invention and
having several dredging chambers therein, the view showing two chambers arranged
to operate as a pneumatic caisson and one chamber arranged for use as an open
caisson;
Figure 5 is an inverted plan of the caisson shown in Figure 4; and
Figure 6 is an enlarged detail sectional view of the preferred form of packing
which may be used with either form of caisson.
The caisson 10 is of the ordinary open kind having an inclined lower edge 11
which enables it to be driven down through the mud, silt, sand, and gravel beneath
the water and the caisson may be made in
any suitable way and may be built up in
sections in the ordinary manner so as to make it of the necessary height. As shown
in the drawings, it is provided with double walls braced by the cross-braces 12, but
the details of construction I do not claim as my invention.
The caisson is adapted to be used in the ordinary way as an open caisson, and
when it is to be converted into a pneumatic caisson, a roof or bell 13 is used which
is adapted to be lowered down into the open caisson and is provided with a
depending flange 14 which extends parallel with the inner wall of the open caisson.
The joint between the roof or bell and the open caisson may be packed in any
convenient way, and in Figures 3 and 6 I have shewn two means of properly
packing the joint. As shown in Figure 3, the flange 14 is provided at intervals
near the top and bottom with supporting cleats 15 through which extend bolts 16,
the outer ends of which are received in sockets 17 in the wall of the caisson 10
while the inner ends of the bolts are threaded and provided with adjusting nuts 18,
a suitable packing being inserted between the nuts and the cleats 15. Against the
inner ends of the bolts 16 bear screws 19 turning in lugs 20 by slacking which
screws the bolts may be quickly loosened when desired. Hydraulic presses,
supplied with power from above, will be used whenever it is desired to lower the
bell and shaft without air within them. A packing 20° is placed at the lower edge
of the flange 14 between it and the adjacent wall of the open caisson 10 which is
preferably inclined inward at this point, as shown in Figure 3. The preferred
form of packing is shown, however, in Figure 6. Here, the bolts 21 having nuts 22
extend through the flange 14 and enter the sockets 17 and between the flauge and
the adjacent wall of the caisson 10 are expansible tubes 23 which are connected
with pipes 24 adapted to connect with the mechanism for supplying air to the
dredging chamber, or the tubes 23 may be inflated in any other way so as to effect.
a perfectly tight joint.
In Figures 4 and 5 I have shewn an open caisson provided with a number of
chambers, these being formed by the partitions 28 which terminate at their lower
ends in edges adapted to sink readily through the material beneath the water, and
the chambers 29 formed between the partitions of the caisson have dredging
passages 29ª opening upward through the caisson. These passages may be closed
at their lower ends by bells or roofs 30 which are similar to the bell or roof
described above, except that they are smaller, and opening upward from these bells
are shafts 25 which serve as working shafts in the manner already described and
are provided with suitable locks 26 at their lower or upper ends. As shown in
Figure 4, two of the chambers 29 are arranged to be used as pneumatic chambers
the bells 30 being fastened in place above them, and the other chamber 29 and its
passage 29 serve the purpose of an ordinary open caisson, and it will be seen that

page_text: the arrangement described provides for using one or more chambers as open caissons
and one or more as pneumatic caissons, as circumstances require.
The apparatus is used in the following way-The open caisson 10 is sunk
downward through the mud, silt, sand, and gravel, by dredging from within and
beneath it and used as long as it conveniently can be as an open caisson and when
the more solid bottom is reached or the side edges of the caisson strike an
obstruction the bell or bells, as the case may be, and the shafts are lowered down-
ward into the caisson and secured firmly in place in the manner described, or by
any other means that will properly connect the bell or roof to the caisson.
Compressed air is then forced downward into the dredging chamber or chambers,
thus forcing out the water and leaving the chamber in condition for the men to
work within it, and the men. and. materials may be lowered in the ordinary way
through the passage 25. When the desired level is reached and all the work
necessary to complete in air is done, the men are withdrawn, the compressed air
removed, the bell removed, and the concrete lowered through the water and filled
up within the open caisson to a point where it is desirable to pump out the water
and complete the structure. There may be cases where only the sinking of the
caisson is desired, as in the case of sinking shafts.
The upper part of the caisson may be made in detachable sections like the sides
of an ordinary floating caisson for convenience in removal after the masonry is
built.
I do not claim the construction of either the open caisson or the bell as a part of
my invention, as open caissons and diving bells have long been used individually,
but the combination. described and the convertible feature illustrated and set forth
above is believed to be new:
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. The combination, with the open caisson, of a detachable bell or bells to fit
within the open caisson and provided with a suitable shaft or shafts, substantially
as described.
2. A convertible caisson comprising an open main caisson and a removable bell
or roof to fit within. the open caisson and provided with a suitable shaft, substantially
as described.
3. The combination of the main caisson, a detachable bell to fit therein, and the
inflatable packing tubes held between. the walls of the bell and caisson, substantially
as described.
4. The convertible caisson constructed. and arranged to operate substantially as
shown in the accompanying drawings.
Dated this 8th day of June 1859.
VLCC GIS that y
300 TO
1000.
J. F. O'ROURKE,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.