A NEW OR IMPROVED EXCAVATOR
Year: 1873

page_text: LETTERS PATENT to David Rowan, of the City of Glasgow, in the
County of Lanark, North Britain, Engineer, for the Invention of
"A NEW OR IMPROVED EXCAVATOR.”
Sealed the 13th March 1874, and dated the 11th November 1873.
PROVISIONAL SPECIFICATION left by the said David Rowan at the
Office of the Commissioners of Patents, with his Petition, on the
11th November 1873.
I, DAVID ROWAN, of the City of Glasgow, in the County of Lanark,
North Britain, Engineer, do hereby declare the nature of the said
Invention for "A NEW OR IMPROVED EXCAVATOR," to be as follows:-
This said Invention has reference to a new or improved construction
and arrangement of the parts of an excavator or excavating apparatus
for digging and lifting the earth and small stones and water out of the
hollow iron, brick, stone, concrete, or other cylinders or caissons while
sinking these for foundations, applicable also for the sinking of other
foundations, pits, or walls, and for dredging and other like purposes,

page_text: which excavating apparatus is more durable and acts more efficiently
than those at present in use. And the nature and novelty of this
Invention consist in making the outer shell of four or other number of
loose, movable, sectional, or segmental, curved or domed plates of sheet
iron or steel, jointed so as to form close abutting or overlapping joints at
their edge in a semi-spherical or bowl shape below and open above.
These sections or segments are plain on the outside, but on the inside
they are each strengthened by strong radial ribs at the centre of a
double angle iron or other equivalent shape by which they are jointed
near their upper open circular or spherical edges to the lower ends of a
corresponding number of strong bow-shaped sustaining arms (attached
to the lower end of a long hollow spindle) on which they each oscillate,
so that their lower points are drawn towards the vertical position to form
large sharp pointed or scoop-shaped diggers while being lowered into the
earth or material to be excavated by a link attached to each of the said
central ribs continued up as a short lever above its oscillating centre, which
links are all connected to a collar sliding loosely on the middle of the
outer hollow spindle for a short distance, sufficient to so tilt the diggers
before this collar, and a weighted box on it abuts against a fixed collar
on the top of this spindle to carry the whole excavator by a chain
attached by one or more shackles and links to the said sliding collar
while being lowered as stated, and they are tilted or drawn in and up
again into the spherical or bowl shape to dredge in and lift the material
they before dug into and grasped powerfully by the first action and
motion of a strong solid and central spindle (working loosely in the said
hollow spindle), connected at its lower end by long links jointed also
near the point of each said angle iron rib so as to act with a powerful
leverage in either pulling in or keeping out the said digging sections
(forming the shell of this excavator) by the whole weight of the hollow
spindle sustaining arms, weighted box, and excavator above the joints
near their points by which the whole is lifted through said links con-
nected to the lower end of the central spindle to the top of which the
lifting chain is attached some distance above the hollow spindle, and
which is slackened when the whole is carried by the lowering chain
attached to the sliding boss so that this heavy central spindle then acts
with the whole of its weight on its lower angled links in forcing the
diggers down into the earth, and outwards into their vertical position in
addition to the drawing action of the upper links attached to the scoop
şides above their oscillating centres, and to the lowering loose collar;

page_text: but it is to be understood that the lowering chain and weight might be
attached to the outer hollow spindle, direct, without the sliding collar and
the weight and upper links, although I prefer these to insure the opening
and closing of the sections of the excavator by the double action of drawing
and pushing. The said lifting and lowering chains are wound and
unwound by a chain barrel to each, to effect the purposes described, by
any ordinary motive power or hand crab or crab winch or crane, the
one chain being always left slack when the other is carrying the
excavator.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said David Rowan in the Great Seal Patent Office on
the 8th May 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID
ROWAN, of the City of Glasgow, in the County of Lanark, North
Britain, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of November, in the
year of our Lord One thousand eight hundred and seventy-three, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said David Rowan, Her special
licence that I, the said David Rowan, my executors, administrators,
and assigns, or such others as I, the said David Rowan, 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
therein 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 "A NEW OR IMPROVED
EXCAVATOR," upon the condition (amongst others) that I, the said David
Rowan, 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.

page_text: NOW KNOW YE, that I, the said David Rowan, 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
Sheet of Drawings, and to the letters and figures marked thereon, that
is to say:-
My said Invention has reference to a new or improved construction
and arrangement of the parts of an excavator or excavating apparatus
for digging and lifting the earth and small stones and water out of
the hollow iron, brick, stone, concrete, or other cylinders or caissons
while sinking these for foundations (either above or below water),
applicable also for the sinking of other foundations, pits, or wells,
and for dredging and other like purposes, which excavating apparatus
is more durable, and acts more efficiently than those at present or here-
tofore in use.
And in order that the nature, novelty, and mode of performing my
said Invention may be fully understood, I shall now proceed to describe
the several Figures on the Sheet of Drawings which I havo hereunto
appended for the purpose of showing the best modes and means I
am at present aware of for putting the Invention into effect or practice,
the same reference letters and numerals indicating the same or like
parts in all the Figures where shown.
---
Figures 1 and 2 are respectively a sectional elevation and a side
elevation at right angles to cach other, and Figures 3 and 4 are plans
or horizontal sections respectively taken on the lines 1 1 and
22 in Figure 1 to which they correspond, and all constructed
in accordance with and illustrative of one modification of my said
Invention, or construction and arrangement of the parts of my said
new or improved excavator.
Figures 5 and 6 are a sectional elevation and plan of a modification
of my said new or improved excavator, somewhat simpler in its con-
struction and action than that shown in Figures 1 to 4.
Referring to the Figures 1 to 4 inclusive this modification of my
Invention and excavator consists in making the outer shell for ex-
cavating and lifting the material of four or other number of loose
oscillating sections or segments of curved or domed plates A. of sheet
iron or steel jointed so as to form close abutting, or it might be

page_text: overlapping joints at their edges A³, and in a semi-spherical or bowl
shape below at A", and open above at A³, see Figures 1 and 4, where
the excavator is shown closed. These curved sections or scoop segments
A are preferably plain on the inside and outside, except where they
are each strengthened and carried by strong broad ribs B of wrought
iron, preferably riveted radially up the middle of the outside, and
carried up above the top to Bu, Figure 2 (but it might be up the
inside, and be of double angle iron, or other equivalent strong shape,
all so far in a usual manner), by which and where they are each
hinged or jointed in a new or improved manner as levers on the
inside of the upper open circular or spherical edges at C to the
extreme outer and lower ends of each of a corresponding number of
strong radial or bow-shaped sustaining arms D formed with a large
heavy eye or boss D¹ riveted or otherwise attached to the lower end
of the long hollow spindle E, or it might be without this spindle E,
as shown in Figures 5 and 6.
Each section A, B, oscillates on a joint pin at C passed through a
joint formed by the inner upper part of the two steadying ears Bч so
that their lower points A" are opened towards the vertical position to
form large sharp-pointed or scoop-shaped diggers (as shown in Figure 2
and indicated in dotted lines in Figure 1 in this modification and case),
while being hung and lowered into the earth or material Z to be
excavated (as seen in Figure 2) by an ordinary arrangement of single
winding chain at X above, connected below by two short coupling chains,
shackles, and links x, x, to an ordinary collar F and four common
angled links F, each attached at their lower end by a joint and joint
pin 0¹¹ to the upper part B" of each central strengthening rib B of the
new or improved lever sections A, B, continued up as a short back
lever B¹¹ and guiding ears above the new oscillating centre C, all so
that the raising of the links F¹ and their loose collar F carrying the box
or set of weights G on it, slide for a short distance on the middle of the
outer hollow spindle E before the top G¹ of the box or eye of the
weight G abuts against the fixed collar H on the top of the hollow
spindle E sufficient to turn or tilt the diggers A, B, on their said
fulcra C, while the whole excavator is being carried and lowered (by the
said chain at X, attached in this case to the said sliding collar F) into
the material Z to be excavated and removed, all as before stated and
shown in Figure 2. While the sections A, B, are being thus drawn to

page_text: their vertical digging position, as stated, on their new centres C through
the short upper back arms B" and lowering winding chain x, X, they
are themselves also pushed out to that position on these fulcra C as
levers of the first order, in a new or improved manner through the
slacking of the second ordinary winding chain Y attached by a shackle
to the top of the usual central bar or spindle I, made preferably solid
and heavy and connected in a new manner at its lower end I¹ to the
upper ends of as many new rigid links I² as there are sections A, B, as
four in this case, having the lower end of each connected by a joint
pin C¹ to the snug B¹ formed on the lower end of the strap B passed
through the body A of each section to the inside near the point at A",
thus making the sections A, B, levers which are tilted or pushed
downwards and outwards into the vertical digging position, as shown in
Figure 2, by the whole weight of themselves and that of the heavy bar I
acting on them through their new connecting links I as powerful levers
of the togle class, or vice versa ; when the whole is lifted by the chain Y
and the chain x, X, is slackened the sections A, B, are also powerfully
drawn in and up again into the closc spherical or bowl shape (as shown
in Figures 1 and 4) to dredge in and lift the material Z they had before
been dug into with a powerful grappling action, by the first lifting
motion of the said togle links or levers I* assisted by the whole weight
of the hollow spindle E, boss and arms D¹, D, and that of the
supplementary weights [G, thus grappling in the material Z to be
excavated, the weight of which and of the sections A, B, themselves
above and on the outside of the suspending joint C¹ near their points by
these improvements also assist the powerful closing of the sections.
From the foregoing description and reference to Figures 1 to 4 it will
be evident to engineers that the lowering chain x, X, might be attached
direct to the outer hollow spindle E or its collar H, or otherwise direct
to the boss D¹ of the arms D, without the use of the intermediate sliding
collar F, weights G, and upper outer links F¹, and when a supplementary
or greater weight was desired this might be attached to or formed on the
boss D¹ of the arms D; although in some cases, as for excavating stiff
earth or material, I prefer the use of these parts F, F¹, and G, as shown
in Figures 1 to 4, to further insure the opening and closing of the
sections A, B, of the excavator by the double action of drawing and
pushing, all as shown in Figures 5 and 6. Thus, then, the construction
and action of the simple modification of my said new or improved

page_text: excavator, shown in Figures 5 and 6, is otherwise substantially the same
as described in reference to Figures 1 to 4, that is, while the whole is
being hung or lowered by the coupling chains x, x, and its winding chain.
connected at X, and the chain Y is slackened, the sections A, B, are
6 forced open by their togle levers I³, and the weight of the central spindle
I, I, and their own weight, on their fulcra C, and the weight of the
excavated material inside when discharging the same (as indicated in
this open position in dotted lines in Figure 5) and the sections A, B, are
drawn up into the close position (when they have been lowered or sunk
into the material to be excavated by the whole weight of the apparatus)
by slacking the chains x, X, and slowly lifting on the chain Y, which
powerfully draws in the points of the sections by the new links or levers
I while they are being pressed down by their whole weight and that of
the boss and arm D', D, into and so as to grapple or scoop up the
5 material Z within the sections while they are being closed up into the
bowl shape by the whole weight of the sections A, B, and sustaining
arms and boss D, D', as shown in the sharp lines in Figures 5 and 6.
The said lifting or winding of either of the chains X or Y, and the
lowering or slacking of the chains Y or X, respectively, to effect the
O purpose described, may be effected by any ordinary motive power or
hand crab, or crab winch or crane used for other excavators of this class,
the one chain being always left slack when the other is carrying the
excavator.
t
Having thus described and particularly ascertained the nature of my
5 said Invention, and the manner in which the same is or may be used or
carried into effect, I wish it to be understood that I do not confine or
restrict myself to the precise details or arrangements which I have had
occasion to describe and delineate, as many variations may be made
therefrom without departing from the main or essential features thereof,
O neither on the other hand do I desire to claim the application to sectional
excavators of a central solid and hollow spindle, either with or without
a sliding weight, collar, and links, connected to the upper and outer
extremities of the sections or their connecting winding chains separately
or collectively by themselves (as these may have been in use heretofore)
5 except in combination with my said Invention or improvements as
herein specified, but what I consider novel and original, and therefor
claim as the Invention secured to me by the herein-before in part recited
Letters Patent is,-

page_text: First. The construction and arrangement of the parts of an excavator
and mode of actuating the same, all substantially in the two new or
improved modes, and for the purposes herein described and shown in the
accompanying Drawings.
Second. The construction of an excavator having its digging and t
lifting sections themselves fulcrummed as powerful levers, opened and
closed by links or levers jointed near their digging end and to the lower
end of a bar sliding through the spindle or the eye of the arms carrying
their fulcra, either with or without the sliding collar and weight F, G,
and links F¹ as desired, all substantially as and for the purposes herein 1
described or as shown in the accompanying Drawings.
In witness whereof, I, the said David Rowan, have hereunto set
my hand and seal, this Seventh day of May, in the year of our
Lord One thousand eight hundred and seventy-four.
Witness,
W. R. M. THOMSON,
Patent Agent,
Glasgow.
DAVID ROWAN. (L.S.)