IMPROVEMENTS IN APPARATUS FOR EXCAVATING
Year: 1866

page_text: LETTERS PATENT to John Milroy, of Edinburgh, in the County of Mid
Lothian, North Britain, for the Invention of "IMPROVEMENTS IN
APPARATUS FOR EXCAVATING."
Sealed the 11th December 1866, and dated the 26th June 1866.
PROVISIONAL SPECIFICATION left by the said John Milroy at the
Office of the Commissioners of Patents, with his Petition, on the 26th
June 1866.
I, JOHN MILROY, of Edinburgh, in the County of Mid Lothian, North
Britain, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN APPARATUS FOR EXCAVATING," to be as follows, that is to say :-
This Invention relates to improved apparatus for excavating in a simple,
economical, and expeditious manner, and is more particularly designed for
making excavations on dry land or under water to receive cylindrical iron
casings to form piers, foundations, or pillars for supporting bridges and other
structures; it may also be used for sinking pits and wells, for dredging, and
for other similar purposes.
In the improved apparatus a series of spades or digging and lifting blades
are hinged to a horizontal framework with raised edges, into the interstices
of which they exactly fit when closed. The frame may be circular, square,
or polygonal in figure to suit the shape of the excavation to be made with it.
The spades are of a form varying with that of the frame and of the holo or

page_text: space to be excavated; generally they are in the shape of a triangle with a
piece cut off the apex. When the apparatus is lowered over the spot to be
excavated the spades are open, standing vertically or nearly so, and are pre-
vented from turning back too far by stops. The spades having settled into
the carth, or having been forced into it in the manner hercin-after described,
are drawn inwards, and earth with them, each into its own opening in the
frame, which thus in ascending forms a close vessel.
The various changes necessary to bring about the above results are effected
as follows: With the end of the main chain or rope, which is worked by
the engine or other hoisting machine employed to raise or lower the apparatus,
the excavator is attached by two sets of chains. The chains of set No. 1,
all of equal length, are each fixed to the back or outside of a spade or to the
frame, and after uniting are joined to the main chain a short way above its
junction with sct No. 2 by a length of single chain, which is looped up when
necessary by a monkey hook or otherwise. This set No. 1 when the con-
necting chain is looped up is brought into play in lowering the excavator,
and also serves, if attached to the spades, to keep them in a vertical position.
The chains of set No. 2, all of equal length, are each attached at one end to
the inside of a spade, and at the other to the end of the main chain; they
are for the purpose of pulling in the spades up to the frame with the earth
which they drag with them, and for raising the whole machine to the surface.
In lowering the excavator the connecting chain of set No. 1 is looped up and
suspended on a monkey hook (set No. 2 being thus quite slack) until the
excavator reaches the bottom, when the monkey hook is thrown out of gear
by means of a chain or otherwise. The chains of set No. 1 are thus thrown
loose, and on the hoisting being set about those of set No. 2 are brought into
play, draw in the spades, and raise the whole machine to the surface.
It is frequently necessary to insure the excavators being kept and forced down
at the moment when the spades are being drawn into their places in the frame.
This may be effected as follows:-Two chains are fixed to the excavator
on opposite sides to each other. Each chain passes under a pulley sunk at
a convenient distance from the bottom of the cylinder, well, or excavation, is
carried to the top, and passed over or attached to a capstan, crab, or winch.
When the machine has reached the ground sufficient strain put upon these
chains will force the spades into the ground, keep them there when being
drawn in, and secure their obtaining a hold of the earth. As soon as the
spades are drawn in the holding down chains are released, and the whole
machine is raised to a convenient height for emptying its contents into a wagon
or other receptacle for removal by allowing the spades to fall open. The frame

page_text: may also be held in the ground by a simple adjustment of weighs of
as may be found most suited to the character of the spot to be excavated.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Milroy in the Great Seal Patent Office on the
21st December 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
MILROY, of Edinburgh, in the County of Mid Lothian, North Britain, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of Junc, in the year of our
Lord One thousand eight hundred and sixty-six, in the thirtieth year of
Her reign did, for Herself, Her heirs and successors, give and grant unto
me, the said John Milroy, Her special licence, that I, the said John
Milroy, my executors, administrators, and assigns, or such others as I, the
said John Milroy, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times thereafter
during the term thercin expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN APPARATUS FOR EXCAVATING," upon the condition (amongst others)
that I, the said John Milroy, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that the said John Milroy, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement in writing, reference being had to the accompanying Drawings,
that is to say:-
My said Invention relates to improved apparatus for excavating in a
simple, economical, and expeditious manner, and the apparatus is more
particularly designed for making excavations on dry land or under water
within cylindrical iron or other casings to form piers, foundations, or pillars
for supporting bridges and other structures. The improved apparatus may
also be used for sinking pits and wells, for dredging, and for other similar
DumosAR

page_text: And in order that my said Invention, and the manner of performing the
same may be properly understood, I have hereunto appended two Sheets of
explanatory Drawings, to be hercin-after referred to, and representing a
convenient and practically successful modification of my improved apparatus.
Figure 1, on Sheet 1 of the Drawings, is a side elevation, partly in vertical
section, of the excavator, as the principal part of the improved apparatus may
bo termed, and Figure 2 is a plan thereof; Figures 3 and 4, on Sheet 2, are
vertical sections as taken at right angles to each other, showing by way of
example the manner of using the apparatus for excavating earth from within
cylindrical casings 3, supposed to be in process of being sunk for the purpose
of forming piers or foundations for a bridge, the operation being performed
without its being necessary to pump the water out of the casing. The same
reference numerals and letters are used to mark the same or like parts in all
the Figures.
In the improved apparatus a series of spades or digging and lifting blades 1
are hinged to a horizontal framework 2 with a raised rim, into the interstices
of which framework they exactly fit when closed. The frame 2 may be
circular, square, or polygonal in figure to suit the shape of the excavation to
be made with it, but in the modification represented in the Drawings it is
octagonal in plan. The spades 1 are of a form varying with that of the
frame 2; generally they arc in the shape of a triangle with a piece cut off the
apex, as represented in the Drawing, and they are hinged (in this example) to
the rim or outer sides of the frame, whilst they are formed with sides pro-
jecting inwards to enable them to take better hold of the earth. When the
apparatus is being lowered over the spot to be excavated the spades 1 are
open and hung vertically or nearly so, as shown in Figures 1 and 3. The
apparatus is lowered as far as it will go with the spades in the open vertical
position, and the spades having settled into the earth, or having been forced into
it in the manner herein-after described, are drawn inwards through the ground
and earth with them, each into its own opening in the frame 2, which is
thereby formed into a close vessel, and is drawn up in that condition with a
quantity of earth in or upon it. The bottom or narrow ends of the spades 1
are brought up against a ring forming the centre of the frame 2 and con-
nected by radial ribs to the outer part of the frame. A lining or packing of
yulcanised rubber is applied to the centre and to the radial ribs for the edges
of the spades to close upon to form a tight joint. The various changes
necessary to bring about the above results are effected by the means now
about to be described. With the end of the main rope or chain 4, which is
worked by an engine as indicated at 5 in Figure 3, or by some other hoisting

page_text: machine, and which is employed to raise or lower the apparatus, the excavator
is attached by two sets of chains A, B. The chains of set A, all of equal
length, are each fixed to the frame 2, and after uniting upon a ring are joined
to the main chain 4 a short way above its junction with the other set of
chains B by a length of single chain 6, which is looped up when the apparatus
is descending by a monkey hook 7, or otherwise. The set of chains A. is
represented as consisting of four chains; there may, however, be eight chains
in this set which may pass over the rim of the frame to points of attachment
on the backs or outsides of the spades 1. In this case the spades 1 must be
fitted with stops to arrest them in the vertical position, as when the chains A
are drawn tight they will otherwise turn them too far outwards. There are eight
chains of set B, all of equal length, and they are attached at their upper ends to
the end of the main chain 4. These chains B are for the purpose of pulling in
the spades 1 up to the frame 2 with the earth which they drag with them, and
for raising the whole machine to the staging above. When lowering the
excavator the connecting chain 6 of the outer set of chains A is looped up by
means of the monkey hook 7 (the chains of set B being thereby rendered
quite slack) until the excavator reaches the bottom. The monkey hook 7 is
then thrown out of gear by means of a rope 8, which slackens the outer set
of chains A, and upon the hoisting being set about the inner set of chains B
are brought into tension, draw in the spades 1, and raise the whole machine
to the surface.
It is frequently necessary to insure the excavators being kept and forced
down at the moment when the spades 1 are being drawn into their places in
the frame 2; this may be effected by means of two chains 9, shown in
Figure 3, and which are fixed to opposite sides of the frame 2; these chains 9
pass under pulleys held down within a convenient distance from the bottom of
the excavation, and thence up to winding axles 10 at the staging above.
These winding axles 10 are formed with enlarged drums and also with handles
for turning them by, and the holding-down chains 9 are hauled up quickly by
unwinding or drawing ropes off the drums, on which they are rewound by the
operation of drawing up the excavator. In the arrangement shown in
Figures 3 and 4 the bottom pulleys for the holding-down chains 9 are carried
by wooden spars or leaders 11, which are held inside the cylinders 3, being
kept apart at their lower ends by being there fixed to opposite sides of a
strong iron hoop, whilst their upper ends are fixed to the cylinder itself;
these spars or leaders 11 move downwards with the cylinders 3 as the excava-
tion proceeds. The chains 9 are hauled tight as the excavator descends, and
when it has reached the ground sufficient strain is put on them to force the

page_text: spades 1 into the earth to keep the frame 2 from rising whilst they are being
drawn inwards, and to insure their taking hold of the ground. As soon as
the workmen feel that the spades 1 are drawn close in, the holding-down
chains 9 are released, and the excavator is raised up to a height convenient
for emptying its contents. A lorry or wagon is moved beneath the excavator
for it to rest on; the outer set of chains A are then hooked up and the
excavator being raised a little the spades 1 fall open, discharging their contents
into the lorry, which is then removed, and the excavator is lowered again. In
some cases the frame 2 may be conveniently made sufficiently heavy to keep
down of itself, whilst the spades 1 are being drawn in, in which cases the
holding-down chains 9 may be dispensed with. The proportions and form of
the parts of the apparatus, and the special appliances used may be varied to
suit the character of the spot to be excavated in each case, whilst the
economical applicability of the apparatus will of course depend upon the
nature of the soil to be dealt with. Thus the centre of the frame 2 may be
held by inclined ribs at a lower level than the outer rim, and the spades 1 may
be concave or scoop-shaped. The spades 1 may also in some cases be formed
with prongs to facilitate their entrance amongst gravel.
Having thus particularly described my said Invention, and the manner in
which the same is to be performed, I have to state that I do not restrict
myself to the precise details herein described or delineated, but that what I
believe to be novel and original, and claim as the Invention secured to me by
the herein-before in part recited Letters Patent is, the constructing, arranging,
and working of excavating apparatus, substantially in the improved manner
herein-before described.
In witness whereof, I, the said John Milroy, have hereunto set my
hand and seal, this Twentieth day of December, in the year of our
Lord One thousand eight hundred and sixty-six.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
JOHN MILROY. (L.S.)