PROVEMENTS IN EXCAVATING MACHINERY."
Year: 1861

page_text: PROVEMENTS IN EXCAVATING MACHINERY." A communication from abroad
by Messrs. Francis Burgess Scott. James Brayley, and John Beman Pitts,
all of the City of Buffalo. in the County of Erie and State of New York,
United States of America.
Sealed the 3rd December 1861. and dated the 29th June 1861.
PROVISIONAL SPECIFICATION left by the said William Clark at the
Office of the Commissioners of Patents, with his Petition, on the
29th June 1861.
1, WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex,
Engineer & Patent Agent, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN EXCAVATING MACHINERY," to be as follows:--
The purpose of these improvements is. more especially to adapt excavating
machinery to deep tile draining. They consist in a certain mode of applying
and operating a rotary spade wheel, whereby it is made capable of working
with its axis below the surface of the ground while driven by machinery above
the surface; also in certain improved means of cleaning and carrying away the
dirt from the spades after they have raised it above the surface of the ground;
1 S1

page_text: also in a certain construction of the framing of the machine to provide for the
raising and lowering of the spade wheel; also in certain means of guaging the
line of descent of the bottom of the trench or ditch dug by the machine; and,
further, in certain means of preventing the falling back into the trench or
ditch of the dirt which may fall from the spades after having been raised
above the surface of the ground.
The Invention is illustrated in the accompanying Drawing, in which Fig. 1
is a central longitudinal vertical section of a machine with my improvements;
Fig. 4 is a plan of the spade wheel and its supporting shields; Fig. 5 exhibits
a modification of pari of the machine. Similar letters of reference indicate
corresponding parts in the several Figures.
A is the spade wheel carrying the spades a, . held in its place by its axle b,
being supported in bearings in the ive shields B. B. which are secured to the
portion W of the framing of the machinery. The spade wheel is rotated by
bevil gears working in cogs attached to or formed upon its opposite sides;
gearing on one side only may be used, bui on each side is better, as the two
hold the wheel more firmly in place, and give it greater strength. In place of
the second bevil gear a small roller might be used on one side to steady the
spade wheel. Instead of bevil gears working into the sides. spur gears
working into spur teeth on the inferior of the rim of the spade wheel would
accomplish the same purpose, viz., allowing the said wheel to work in the trench
with its axis below the surface of the ground. The bevil gears are carried
by two shafts C', fitted to bearings provided in or secured to the portion W of
the framing, and these shafts are furnished with mitre gears E. E; F. F.
are corresponding mitre wheels fitted on a horizontal shaft F'. fitted to bearings
on the top of the part W of the framing. On the same shaft F' there is a
pulley G, which receives a belt K from a pulley H on a shaft H', arranged in
bearings at the junction of the portions W and W of the framing, and on
this shaft H there is another pulley, which receives a belt J from a pulley J
on the driving shaft J of the machine, which works in bearings supported in
the part of the framing. This shaft may be the crank shaft of the steam
engine. The boiler X for supplying steam to this engine is represented in
Figure supported on the portion W of the framing. The framing of the
machine is made in two parts W, W. to permit the raising and lowering of
the spade wheel, the said parts heing connected together at the top by a hinge
joint, indicated by c. c, to which the shaft. H forms a centre bolt, or which
may be otherwise so constructed that the said shaft is in line with the axis of
motion of the hinges which permits the raising & lowering of the part W,
which carries the spade wheel without slackening either of the belts K. Je,

page_text: To provide for the raising and lowering of the said part W, the said part W
has rigidly attached to it at opposite sides two curved racks I, into which gear
two pinions on the shaft d, fitted to bearings secured to the part W, and
worked by a hand crank or other suitable means. In Figure 1, the part W
of the frame is shown in red outline in an elevated position. To clear the
earth from the spades, as in their revolution with the wheel A, they severally
come up to the top clearers M, M, are attached to an endless chain M',
supported by sprocket wheels M, M², on two shafts e, e, supported in bearings
in the sides of a platform N, which rests on the bottom of the portion W of
the framing. This endless chain is above the reach of the spades, & the
clearers passing between the spades, carry the earth out along the bottom
and over the end of the platform N, and deposit it at a safe distance
The
from the spade wheel and the trench that is being dug by it.
position of the endless chain relatively to the spade wheel is not directly
across, but at such an angle that the clearers can pass between the spades
without coming in contact with them. The endless chain derives motion
from a spur wheel on one of the shafts C, C, gearing with a spur gear h
on a shaft i, on which is a bevil gear gearing with a bevil gear on
of the sprocket wheel shafts e, e. As in working in an adhesive soil the
clearers themselves would soon become clogged, each one is caused to rise
and fall before a scraper arranged across and attached to the endless chain
immediately in front of the clearer. To raise the clearers past the scraper
there is attached to the upper part of each a small roller, which on coming
near the place of discharge run up an inclined way attached to the platform N
until the clearer is raised sufliciently high to scrape itself with the scraper.
The rollers after passing the top of the inclination run in and along a guide to
keep the clearers in place in passing round the sprocket wheels; slotted bars
may be substituted for the scrapers, the clearers passing through the slots of
said bars.
one
The clearers, instead of being attached to an endless chain, might be attached
to a wheel, as shown in Fig. 5, in which case they could be raised and lowered
past the scrapers or through the slotted bars by the rollers or slides running in
a fixed cam groove p. Fig. 5, whose distance from the wheel is greater on one
side than the other, the said cam groove being the same to the wheel as the
inclined way is to the endless chain. To enable the machine to be moved
forward and held up to its work, there is provided for it a movable track T, T,
on which there are toothed racks T, T. in which the two large toothed
wheels U work, said wheels being moved to propel the machine by pinions.
V, V, on the centre shaft H, before described. The wheels U, U, are

page_text: attached to the portion W of the framing, so that they may not be raised on
raising the spade wheel. To keep the track from moving out of its place,
stakes are driven in the ground at each end. The wheels U. U. do not sup-
port the weight of the machine. as smooth faced wheels W W W We are
provided for this purpose. To provide for the backing and shifting of the
machine, the two centre wheels WW, are on axles which can be raised
and lowered by screws g. g. operating on sliding axle boxes. By lowering the
axles the machine is raised off the track. the weight being balanced or nearly
so on the two centre wheels, by which means the machine can be easily turned
or shifted. To prevent the falling back into the trench cut by the machine of
any loose dirt which may fall from the spades on their rising above the surface
of the ground, there is placed immediately before the spades a scraper fitting
nearly to the spades, as shown at r, r, in Fig. 1, and presenting in a vertical
direction a form something like an inverted letter V. This scraper is to be so
applied as to allow it to rise and fall freely, and always rest upon the surface
of the ground on opposite sides of the trench, notwithstanding variations in
the form of the surface, and as the said scraper moves forward with the
machine, it will throw the loose fragments to the right and left away from the
margins of the trench. The two sides of this scraper need not be connected
in front, as represented, but may be separate so that they could be set a little
nearer to or further from the sides of the spades. The earth is prevented
from getting into the spade wheel and clogging up the cogs in the sides
thereof by means of the two shields B, B; these shields are fitted to the
wheel within the rim thereof, their edges being flanged internally to fit into
channels in the sides of the wheel. Some kind of packing, such as india-
rubber or some material which will not cause much friction, may be used
between the wheel and the shields to exclude the fine loose particles of dirt.
In case of the spade wheel meeting with large stones, it will be necessary to
back the machine, and use a crowbar or other means of removing them, or in
case of large boulders, it may be desirable to elevate the portion W of the
framing, to raise the spade wheel high enough to pass over it, lowering the
wheel on the other side of it, and proceeding with the operation, leaving
the boulder to be removed by digging round it. The spade wheel when set
upright, and parallel with the sides of the machine and with the tracks, will cut
a parallel-sided trench of a width equal to that of the spades, but a ditch wide at
the top and narrow at the bottom may be cut by setting the wheel in an oblique
position. as illustrated by red outlines in Fig. 4. This may be done either by
setting the machine oblique to the axles of the wheels which support it on
the track, or by making a part of the frame to which the shields and spade

page_text: wheel are attached movable in such manner as to set the said wheel obliquely.
To cut a ditch much wider at the top, it will be desirable first to cut a parallel-
sided trench with the spade wheel in a direct position, the length of the track
laid down. then back the machine, set the machine obliquely. and run forward
again. By this means the earth is prevented pressing against the advance side
of the spade wheel when set obliquely.
In order that in excavating uneven ground the bottom of the trench may
not have a corresponding unevenness, the track may be made to constitute a
guage by grading or blocking its bed to bring it to the line of descent in
which it is intended that the drain shall run. that line being shown stakes
or marks placed according to a previous survey. To operate the machine, the
track is first laid, and the machine with the part. W elevated, as shown in red
outline in Fig. 1, set upon it, and the centre wheels W, W, are lowered
sulliciently to raise the wheels U. U, from the racks on the tracks. The
machine is then set in motion, and the spade wheel allowed to work its way
downward into the ground to the full depth desired before the machine moves
forward. On the proper depth having been arrived at, the centre wheels
WW are raised to let the teeth of the wheels U, U, into the racks on the
track, and the machine begins to move forward, and cut the trench or ditch.
As the machine advances, and leaves behind its track, which is made in
sections, the track is taken up and set down in front in the line marked out.
As the machine proceeds the spades bring up the dirt, which is cleared away
by the clearers operating as herein-before described. The trench made by
the machine will generally not be wide enough for a man to stand in, or work
standing within it, but the tiles can be laid in it with tongs, or with a bent
rod such as is now in common use for the purpose. The principal features
are.-
1st, the shields B. B, at the sides of the spade wheel.
2ndly, the use of clearers M, attached to an endless chain or wheel work-
ing between and in combination with the revolving spades for the purpose
specified.
Brdly, causing the clearers to clear themselves by a movement substan-
tially as herein described in relation to scrapers or slotted bars, such movement
being produced by inclined guides or cams.
4thly, the construction of the framing of the machine in two parts W, W
with hinge joints and centre shaft H' in line with said joints.
5thly, the combination with the excavating machine of a track T, T, and
toothed rack T, T. so employed as to serve as a gauge on the surface of the
ground to determine the line of descent of the bottom of the trench.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Clark in the Great Seal Patent Office on the
28th December 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I WILLIAM
CLARK, of 53, Chancery Lane, in the County of Middlesex, Engineer and
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of June, in the year of our Lord.
One thousand eight hundred and sixty-one, in the twenty-fifth year of
Her reign, did. for Herself. Her heirs and successors, give and grant unto me,
the said William Clark, Her special licence that I, the said William Clark,
my executors. administrators, and assigns, or such others as I. the said
William Clark. my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafier
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 "IMPROVEMENTS IN
EXCAVATING MACHINERY," a communication from abroad by Messrs. Francis
Burgess Scott. James Brayley, and John Beman Pitts, all of the City of
Buffalo. in the County of Erie & State of New York, United States of
America, upon the condition (amongst others) that I, the said William Clark,
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 per-
formed, 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 1. the said William Clark, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed. to be particularly described and ascertained in and by the following
statement, reference being had to the Sheet of Drawings hereunto annexed,
& to the letters and figures marked thereon (that is to say):-
The purpose of these improvements is more especially to adapt excavating
machinery to deep tile draining. They consist in a certain mode of applying
and operating a rotary spade wheel, whereby it is made capable of working

page_text: with its axis below the surface of the ground while driven by machinery above
the surface: also in certain improved means of cleaning and carrying away
the dirt from the spades after they have raised it above the surface of the
ground also in a certain construction of the framing of the machine tn
provide for the raising and lowering of the spade wheel; also in certain means
of guaging the line of descent of the bottom of the trench or ditch dug by
the machine; and, further. in certain means of preventing the falling back
into the trench or ditch of the dirt which may fall from the spades after having
heen raised above the surface of the ground.
The Invention is illustrated in the accompanying Drawing. in which Fig. 1
is a central longitudinal vertical section of a machine, according to this Inven-
tion: Fig. 2 is a plan of the same; Fig. 3 is a transverse section of the
same; Fig. 4 is a plan of the spade wheel, and its supporting shields: Fig. 5
exhibits a modification of part of the machine. Similar letters of reference
indicate corresponding parts in these several Figures.
A is the spade wheel, carrying the spades a, a, held in its place by its axle b,
being supported in bearings in the two shields B, B. which are secured to the
portion W of the framing of the machinery. This spade wheel is rotated by
bevel gears C. D. working in cogs attached to or formed in its opposite sides;
gear on one side only may be used. but one on each side is better, as the two
hold the wheel more firmly in place & give it greater strength. In place of
the second hevil gear a small roller might be used on one side to steady the
spade wheel. Instead of bevil gears working into the sides. spur gears
working into spur teeth on the interior of the rim of the spade wheel would
accomplish the same purpose, viz., allowing the said wheel to work in the
irench with its axis below the surface of the ground. The bevil gears C. D,
are carried by two shafts C'. D¹. fitted to bearings provided to or secured to
the portion W of the framing, and these shafts are furnished with mitre
gears E. E; F. F. are corresponding mitre wheels, fitted on a horizontal
shaft F fitted to bearings in the top of part W of the framing. On the same
shaft F there is a pulley G, which receives a belt K from a pulley H on a
shaft II. arranged in bearings at the junction of the portions W
and W of the framing. and on this shaft H there is another pulley H³,
which receives a belt J from a pulley J on the driving shaft. J' of the machine,
which works in bearings supported in the part W of the framing. This shaft
may be the crank shaft of a steam engine. The boiler X for supplying steam
to this engine is represented in Fig. & Fig. 2, supported on the portion W
of the framing. The framing of the machine is made in two parts W, W, to
permit the raising and lowering of the spade wheel, the said parts being con-

page_text: nected together at the top by a hinge joint indicated by c. c, in Fig. 2, 10
which the shaft H forms a centre bolt, or which may be otherwise so con-
structed that the said shaft is in line with the axis of motion of the hinges.
which permits the raising and lowering of the part W. which carries the spade
wheel without slackening either of the belts K. J. To provide for the
raising and lowering of the said part W, the said part W has rigidly attached
to it at opposite sides two curved racks I, into which gear two pinions 1¹ on a
shaft d fitted to bearings secured to the part W, and worked by a hand crank
or other suitable means. In Fig. 1, the part W of the frame is shown in red
outline in an elevated position. To clear the earth from the spades, as in their
revolution with the wheel A. they severally come up to the top clearers M, M.
are attached to an endless chain M' supported by sprocket wheels M². M². on
two shafts e, e, supported in bearings in the sides of a platform N. which rests
on the bottom of the portion W of the framing. This endless chain is above
the reach of the spades, and the clearers passing between the spades carry the
earth out along the bottom and over the end of the platform N. and deposit
it at a safe distance from the spade wheel and the trench that is being dug by
i. Fig. 2 shows the position of the endless chain relatively to the spade
wheel is not directly across, but at such an angle that the clearers can pass
between the spades without coming in contact with them. The endless chain
derives motion from a spur gear g on one of the shafts (". C, gearing with a
spur gear on a shaft i, on which is a hevil gear gearing with a bevil gear j
on one of the sprocket wheel shafts e. e. As in working in an adhesive soil
the clearers themselves would soon become clogged: each one is caused to rise
and fall before a scraper 1, arranged across and attached to the endless chain
immediately in front of the clearer, as shown in Fig. 3. To raise the clearers
past the scraper there is attached to the upper part of each a small roller m.
see Fig. 3. which on coming near the place of discharge run up an inclined
way R, attached to the platform N. until the clearer is raised sufficiently high
to scrape itself with the scraper. The rollers after passing the top of the
inclination R. run in and along a guide n. o, to keep the clearers in place in
passing round the sprocket wheels. Instead of the rollers m, m, slides might
be used for the same purpose. Slotted bars may be substituted for the
scrapers, the clearers passing through the slots of said bars. The clearers,
instead of being attached to an endless chain, might be attached to a wheel, as
shown in Fig. 5, in which case they could be raised and lowered past the scrapers
or through the slotted bars, by the rollers or slides running in a fixed cam
groove p, whose distance from the wheel is greater on one side than the other,
the said cam groove being the same to the wheel as the inclined way R is to

page_text: the endless chain. To enable the machine to be moved forward and held up
to its work, there is provided for it a movable track T, T, on which there are
toothed racks T¹, T', in which the two larger toothed wheels U work, said
wheels being moved to propel the machine by pinions V, V, on the centre
H', before described. The wheels U, U, are attached to the portion W of the
To
framing, so that they may not be raised on raising the spade wheel.
keep the track from moving out of its place, stakes are driven in the ground
at each end. The wheels U, U, do not support the weight of the machine,
as smooth-faced wheels W, W, W, W2, are provided for this purpose. To pro-
vide for the backing and shifting of the machine, the two centre wheels W³, W³,
are on axles, which can be raised and lowered by screws q, q, operating on
sliding axle boxes. By lowering the axles the machine is raised off the track,
the weight being balanced or nearly so on the two centre wheels, by which
means the machine can be easily turned or shifted. To prevent the falling
back into the trench cut by the machine of any loose dirt which may fall from
the spades, on their rising above the surface of the ground, there is placed imme-
diately before the spades a scraper, fitting nearly to the spades, as shown at
r, r, in Figs. 1 & 2, and presenting in a vertical direction a form something
like an inverted letter V. This scraper is to be so applied as to allow it to
rise and fall freely, and always rest upon the surface of the ground on opposite
sides of the trench, notwithstanding variations in the form of the surface, and
as the said scraper moves forward with the machine it will throw the loose
fragments to the right and left away from the margins of the trench. The two
sides of this scraper need not be connected in front as represented, but may be
separate, so that they could be set a little nearer to or further from the sides
of the spades; the earth is prevented from getting into the spade wheel, and
clogging up the cogs in the sides thereof, by means of the two shields B, B.
These sheilds are fitted to the wheel within the rim thereof, their edges being
flanged internally, as shown at s, s, in Fig. 3, to fit into channels in the sides
of the wheel. Some kind of packing, such as india-rubber, or some material
which will not cause much friction, may be used between the wheel and the
shields to exclude the fine loose particles of dirt. In case of the spade wheel
meeting with large stones, it will be necessary to back the machine and use a
crowbar or other means of removing them, or in case of large boulders; or it
may be desirable to elevate the portion W of the framing to raise the spade
wheel high enough to pass over it, lowering the wheel on the other side of it;
& proceeding with the operation, leaving the boulder to be removed by digging
round it. The spade wheel, when set upright and parallel with the sides of
the machine and with the tracks, will cut a parallel-sided trench, of a width

page_text: equal to that of the spades; but a ditch, wide at the top and narrow at the
bottom, may be cut by setting the wheel in an oblique position, as represented
by red outlines in Fig. 4. This may be done either by setting the machine
oblique to the axles of the wheels which support it on the track, or by making
a part of the frame to which the shields and spade wheel are attached movable,
in such manner as to set the said wheel obliquely. To cut a ditch much
wider at the top it will be desirable first to cut a parallel-sided trench with the
spade wheel in a direct position the length of the track laid down, then back
the machine, set the wheel obliquely, and run forward again. By this means
the earth is prevented pressing against the advance side of the spade wheel
when set obliquely.
In order that in excavating uneven ground the bottom of the trench
may not have a corresponding unevenness, the track may be made to con-
stitute a guage, by grading or blocking its bed to bring it to the line of
descent in which it is intended that the drain shall run, that line being
shown by stakes or marks placed according to a previous survey. To operate
the machine, the track is first laid and the machine with the part W
elevated, as shown in red outline in Fig. 1 set upon it, and the centre wheels
W3, W, are lowered sufficiently to raise the wheels U, U, from the racks on
the tracks. The machine is then set in motion, and the spade wheel allowed
to work its way downward into the ground to the full depth desired before the
machine moves forward. On the proper depth having been arrived at, the
centre wheels W³, W, are raised, to let the teeth of the wheels U, U, into
the racks on the track, and the machine begins to move forward and cut the
trench or ditch. As the machine advances and leaves behind its track, which
is made in sections, the track is taken up and set down in front in the line
marked out. As the machine proceeds, the spades bring up the dirt which is
cleared away by the clearers, operating as herein-before specified. The trench
made by the machine will generally not be wide enough for a man to
stand in, or work standing within it, but the tiles can be laid in it with
tongs or with a bent rod, such as is now in common use for the purpose.
Figs. 6, 7, & 8 represent this excavating machinery of a modified form,
adapted for trenching beyond its supporting rails. Fig. 6 is a side view of a
machine so arranged; Fig. 7, a transverse section of the same, both views
showing it in operation; & Fig. 8 is a section of one of the spades and a
portion of the wheel. Similar letters of reference indicate corresponding parts
in these three Figures.
A, B, is the framing of the machine composed of two principal portions A
and B, of which, for the sake of distinction, A may be termed the travelling

page_text: frame or carriage, and B, the swinging frame; the travelling frame or carriage
being mounted on wheels a, a', to run on a suitable track D, D, and the
swinging frame being arranged to swing at one side of the track D, D, on a
horizontal shaft C, which is arranged parallel with the axles r, r¹, of the
wheel t, t, in bearings b, b, on the travelling frame, and from which the move-
ments of all the working parts of the machine are derived. This shaft C is to be
driven by a steam engine or other motor carried on a platform A¹ of the travel-
line frame, the power either being applied directly to the said shaft, or as repre-
sented in the Drawing, transmitting through a band and two pulleys C¹, F¹,
from a shaft F, which constitutes the driving shaft of the machine; G is the
spade wheel carrying the spades d, d, and having its axle x supported in
bearings in two plates H, H, secured to the bottom of the swinging frame B, the
said plates having their inner faces within the rim of the spade wheel, and having
their outer faces at a distance apart, no greater or very little greater than the
width of the rim of the spade wheel, and less than the width of the spades, so that
they can enter into the trench cut by the spade wheel in the manner shown in
Fig. 2, and so permit the said wheel to enter into the trench past its axle, &
thus enable it to cut a trench of a depth considerably greater than half, say,
about equal to four-fifths of its diameter, or in other words enabling a deep
trench to be cut with a spade wheel of comparatively small diameter. To
provide for the rotary motion of the said wheel, it is constructed with the inner
portion of its rim narrower than the outer portion h, and with a series of
lateral mortises e, e, in the said narrower inner portion of its rim, for the
reception of the teeth of a pinion I on a shaft J, which is arranged to work
in suitable bearings in the swinging frame B, the said shaft deriving motion
through a pair of bevil gears K, L, from the shaft C. The mortises e, e, are
preferable to teeth, for the reason that they are not liable to be choked up; by
making the said mortices in the narrow inner portion of the rim of the wheel,
the gearing is brought within the plane of the outer side edges of the spades,
without which the spade wheel could not be made to enter the ground beyond
the circle of its toothed gearing. The pinion I operates above the bottom of
the swinging frame B, and always above the ground. The spade wheel is
supported on the opposite side to that on which the pinion is situated by an
antifriction roller attached to the frame B. The bevil gears K, L, by which
the spade wheel is driven, permit the raising and lowering of the said wheel by
the swinging movement of the frame B, the said gears always remaining in gear
as in the said movement; the gear L, on the shaft J moves round the gear K
The frame B is lowered and
on the shaft C, in arcs concentric therewith.
raised to allow the spade wheel to descend into the ground to the proper depth

page_text: to commence the cutting of the trench, and to raise the said wheel out of the
trench by means of a tooth sector M, secured firmly to the frame B, concentric
with the shaft C, and a pinion N on a shaft N¹ fitted to bearings on the
frame A. The shaft N is turned to raise & lower the frame B, by means of
a hand crank N firmly secured to it, and the frame is held up to prevent the
descent of the spade wheel any lower than is desired by means of a stop pawl f
applied to the pinion N. The spades may be secured to the wheel in various
ways, but I propose generally to make them as shown in Fig. 8, with tenons i,
fitting to mortices in the exterior of the rim of the wheels, and secure them by
keys, inserted transversely through the rim and tenon, and to provide
shoulders on the rim to support the spades at their backs. P, P¹, are arched
plates secured on the top of the lower part of the swinging frame B, one on
each side of the spade wheel G, and fitted to the sides of that portion of the
spade wheel which stands up within the said frame for the purpose of pre-
venting the dirt which is brought up above the surface of the ground by the
spades from falling over the sides of the upper part of the wheel. These plates are
made concave in their transverse section, as shown in Fig. 6, nearly fitting to
the spade d, d. The plate P nearest the side of the machine is made with a
spout Q, through which the dirt brought up from the trench by the spade
wheel is conveyed away from the said wheel in a direction lateral to the planes
of revolution thereof, the width of the said spout being nearly equal to the
distances between the spades d, d. R is a spade by which the dirt is pushed
out through the spout Q, and delivered upon the surface of the ground at one
side of the machine. This spade is attached firmly to or made with a long
straight stem R', which is arranged to work in a fixed slotted guide m, attached
to the upper part of the frame B, and the said scraper is connected directly
with a crank S' in a shaft S, which is arranged slightly oblique to the planes of
revolution of the spade wheel in bearings n, n, secured to the swinging
frame A. This shaft receives a rotary motion through two bevil gears S³, J²,
from the shaft J, before described, and by this motion the crank S' is caused to
give the spade R a combined longitudinal & oscillating movement, the
velocity of which is so timed by making the gearing of proper proportions that
the said spade is caused to pass through the spaces between the adjacent
spades d, d, as the said spaces are presented opposite the trough Q, by the slow
revolution of the spade wheel, and from thence through the trough Q, and so 3
caused to discharge the dirt from between the spades d, d. In order to keep
the spade R clean, there is attached to the upper part of the swinging frame A,
by arms p, p, a fixed scraper T, so arranged that the said spade in its upward
movement, after every discharge of dirt through the trough Q, passes in

page_text: contact with the said scraper. The arms p, p, should be somewhat elastic to
enable the scraper to scrape the spade R properly. To provide for the certain
and regular advance of the machine along the track D, D, in digging the
trench, the two rails composing the track have toothed racks s, s, at their
sides, and axle r' of the front wheels t, ', is furnished with two cogged
wheels a', a', gearing into the said racks. The said axles is also furnished with
a worm gear n, which gears with an endless screw on an upright shaft U,
which works in bearings in the frame B, and is geared by bevil gears U¹, C¹,
with the shaft C, and through these means the axler derives the necessary
slow rotary motion to effect the forward movement of the machine. To
set the machine in operation, the track D, D, is first laid in the direction
required, and set either level or at any inclination that may be desired for the
bottom of the trench, cutting down the surface of the ground or blocking up
the track when necessary. The machine having the swinging frame B raised
high enough to let the spades d, d, clear the surface of the ground, is then
placed upon the track and set in motion, and the spades d, d, commence
cutting into the ground while the machine moves slowly forward. Before the
machine has travelled far, the spades d, d, will have cut down to the full depth
desired, and the further descent of the swinging frame B, spade wheel, and
their appurtenances is prevented by letting the pawl fall into the pinion N.
As the machine continues travelling onward, the spades D, D, cut the trench
of uniform width, and with its bottom even and parallel with the surface of the
track D, D, which is thus made to constitute a gauge to the depth and level or
inclination of the bottom of the trench. As far as the dirt is brought up to
the top of the spade wheel is cleared out from between the spades d, d, by the
spade R, which deposits it on the ground by the side of the machine, and at
such distance from the trench that there is no danger of its falling back
thereinto. When the machine has run forward nearly to the end of the track
that has been laid down, two new rails are laid down in front, and the operation
may be continued for an indefinite distance with two sections of track taking
up the back one, and placing it in front as often as necessary. In case of the
spade wheel meeting with large stones it will be necessary to back the
machine, and use a crow bar or other means of removing them; or in case of
large boulders it may be desirable to elevate the portion W of the framing to
raise the spade wheel high enough to pass over it, lowering the wheel on the
other side of it, and proceeding with the operation, leaving the boulder to be
removed by digging round it.
The spade wheel, when set upright and parallel with the sides of the machine
and with the tracks, will cut a parallel-sided trench of a width equal to that

page_text: of the spades; but a ditch wide at the top and narrow at the bottom may be
cut by setting the spade wheel in an oblique position. This may be done
cither by setting the machine oblique to the axles of the wheels which support
it on the track, or by making a part of the frame B, to which the plates H, H,
and spade wheel are attached movable, in such manner as to set the said
wheel obliquely. To cut a ditch much wider at the top, it will be desirable
first to cut a parallel-sided trench with the spade wheel in a direct position
the length of the track laid down, then back the machine, set the wheel
obliquely, and run forward again. By this means the earth is prevented from
pressing against the advanced side of the spade wheel when the latter is set
obliquely To prevent any considerable quantity of earth from crowding in at
the sides of the wheel, the two plates K, K, may be so extended as to cover
the entire sides of the spade wheel, with the exception of the outer portion
of the rim thereof, & as before described & represented.
It will be observed, in reference to Fig. 7, that the frame B, carrying the
spade wheel G, the spade R, which clears the dirt from it and their appur-
tenances as arranged at one side of the travelling frame or carriage A, so that
the spade wheel digs the trench at one side of and not between the tracks,
which allows the two rails of the track to be united by cross ties, and so
kept at the correct breadth of guage for the machine to run upon, and which
also provides greater facility for adjustment.
Having described the nature of this Invention, and the manner of per-
forming the same, I declare that what I claim as the Invention to be
protected by the herein-before in part recited Letters Patent, is,-
First, supporting the axle of the spade wheel by plates disposed on each
side, and which fit within the said wheel in such a manner as to allow it to
enter into the trench beyond its axle as described, which plates, in some
cases, form shields at the sides of the spade wheel, as herein-before described.
Secondly, providing the said wheel with a series of mortises e, e, or other
system of gearing arranged within the planes of the sides of the rim of the said
wheel, as described.
Thirdly, the construction of the framing of the machine of two paris, the
one connected to the other by and hinged or swinging on the shaft from
which the several parts derive motion for the purposes & substantially as
herein set forth.
Fourthly, the employment, in combination with a spade wheel, of a
movable track D or T, so used as to constitute a guage to the level or
inclination of the bottom of the trench dug by the said wheel, substantially as
herein described.

page_text: Fifthly, the setting of the swinging frame which carries such spade wheel
and its appurtenances at one side of the travelling frame A; in such manner
that said wheel may operate on one side of the track or tramway, as herein
set forth.
Sixthly, the use of clearers M attached to an endless chain or wheel working
between and in combination with the revolving spades for the purpose
specified; also the employment, in combination with the spade wheel, of a
spade R, or other device, working across the said wheel to clear the dirt from
the spades attached to the wheel after they have brought it above the surface
of the ground, as herein-before described.
Seventhly, causing the clearers to clear themselves by a movement sub-
stantially as herein described in relation to scrapers or slotted bars, such
movement being produced by inclined guides or cams.
Eighthly, the combination of the scraper r, r, with the excavating wheel
substantially as and for the purpose described.
In witness whereof, I, the said William Clark, have hereunto set my
hand and seal, this Twenty-sixth day of December, in the year of
our Lord One thousand eight hundred and sixty-one.
Witness,
JAMES DAISH,
53, Chancery Lane, W.C.
W. CLARK. (L.S.)