IMPROVEMENTS IN DIGGING MACHINES
Year: 1879

page_text: LETTERS PATENT to Thomas Churchman Darby, of Pleshey Lodge, near
Chelmsford, in the County of Essex, for the Invention of "IMPROVEMENTS IN
DIGGING MACHINES.”
Sealed the 31st October 1879, and dated the 5th May 1879.
PROVISIONAL SPECIFICATION left by the said Thomas Churchman Darby
at the Office of the Commissioners of Patents on the 5th May 1879.
THOMAS CHURCHMAN DARBY, of Pleshey Lodge, near Chelmsford, in the County
of Essex. "IMPROVEMENTS IN DIGGING MACHINES."
In the Specification of a former Patent granted to me dated 3rd July 1877,
No. 2555, I described a digging machine in which a number of digging spades or
forks were mounted along one of the longer sides of the implement, and the
implement when at work was caused to nove sidewise over the land.
The spades or forks were carried by and worked in connection with supporting
and propelling legs, whilst the opposite side of the implement was supported on
wheels or rollers.
In order to facilitate the moving of such implements from one field to another or
along common roads I divide the tilling tools into sets, one set at each end of the
implement is mounted together with the propelling legs and supporting wheels in
connection with it on a carriage capable of pivotting below the body of the imple-
ment, so that when it is required to shift the implement from one place to another
the carriage (which has two legs and two wheels) is made to make a quarter turn,
so bringing the wheels in position to allow the implement to travel end foremost
instead of sidewise.
The pivots of the end carriages are set at an angle, so that the act of swivelling
round the carriages in the manner just described somewhat tilts the implement,
and lifts the feet and forks or spades which are at the centre of the implement
clear of the ground; the feet and forks of the end carriages are also lifted clear of
the ground. When all of the feet have been raised clear of the ground, the whole
weight of the implement rests on the four end wheels. One pair of end wheels can
then be driven by gearing from the engine to move the implement from place to
place, whilst the other pair of wheels at the opposite end of the implement may
be used for steering.

page_text: In order to control the amount of forward and backward movement given to
each of the propelling legs when the implement is at work in place of the fulcrums
of the several legs, being all connected together by a rocking bar as described in
the Specification above mentioned, each fulcrum is independent and moves up and
down with the leg, whilst at the same time the leg can be rocked upon it. To be
able to control the height of the fulcrum a vertical screw is fixed on each leg
capable of turning around the screw in a nut cylindrical on its exterior; the out
passes through and is coupled to the block in such manner that the nut can be
turned freely. Fixed on the nut is a pulley which can be revolved by an endless
chain or other mechanical means from a steering shaft, and by turning the nut the
fulcrum can be raised or lowered.
In order that the spits of land turned over by the spades may be divided into
short lengths, I form each spade with a broad chisel edge to cut the land at right
angles to the line of travel of the implement, and also with another edgo extending
behind and at right angles to it. Thus each time the spade enters the land to
separate and turn over a spit, it also makes a cut into the land in rear of the spit
in a line with the direction in which the implement is travelling.
In order to allow the digging forks or spades to be pressed vertically or at any
desired angle into the ground, and to cause them as they leave the ground to throw
over the spit of earth in rear of them, I connect the stem of each fork or spade to
the upper part of the leg, which works it by an expanding spring link. This link
consists of a rod jointed to the leg, and having around it a coiled spring. At the
extremity of the rod is a head against which one end of the spring bears. To the
stem of the fork or spade is jointed one end of a tube. The rod with the coiled
spring around it passes into the other end of the tube, and an end cover is then
screwed into this end of the tube and caused to compress the spring within it.
As the fork or spade enters the ground the link expands and the spring is
compressed, thereby allowing the fork or spade to enter in a straight line until a
stop arrests the expansion of the link. The spade or fork then resumes its curved
course, and so soon as the spit of earth behind it is thereby broken off the spring
expands and contracts the link, so causing the earth to be jerked over. In order
to prevent jar a cushion of vulcanized india rubber or other elastic cushion is
placed inside the tube between the head of the rod and the end of the tube. When
it is required to pulverize the land which is turned over by the spades or forks, I
place in rear of the digging forks or spades rotary harrows or discs, and drive these
from the main shaft of the digging implement.
In place of the spades or forks of a digging machine being moved up and down
with an eccentric motion as described in my former Specification, the stems of the
forks or spades may be jointed to a revolving wheel or frame, and be also coupled
to this frame by a spring, which yields when the point of the fork or spade enters
the ground and allows the spade or fork to enter a certain distance in a straight
line until a stop comes into action; the fork or spade then resumes its circular
motion and breaks off the spit of earth; the spring being so relieved jerks the earth
over.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Thomas Churchman Darby in the Great Seal Patent Office on the
5th November 1879.
THOMAS CHURCHMAN DARBY, of Pleshey Lodge, near Chelmsford, in the County
of Essex. "IMPROVEMENTS IN DIGGING MACHINES."
In the Specification of a former Patent granted to me dated 3rd July 1877,
No. 2555, I described a digging machine in which a number of digging spades or
tools were mounted along one of the longer sides of the implement, and the machine
when at work was caused to move sideways over the land.
The spades or forks were carried by and worked, by preference, in connection
with supporting and propelling legs, whilst the opposite side of the implement was
supported on wheels or rollers.
In order to facilitate the moving of such implement from one field to another or
along cominon roads, I, according to my present Invention, divide the tilling tools
into sets, one set at each end of the implement, together with two of the supporting
wheels, is mounted on a frame or carriage capable of pivotting below the body of
the implement, so that when it is required to shift the implement from one place to
another the carriage or frame with its digging tools and wheels is made to make a
quarter turn, so bringing the wheels in position to allow the machine to travel end
on instead of side wise. Before these are turned the wheels are all in a line on one
side of the implement, whilst the digging tools are along the other side. The
pivots of the end carriages are set at an angle, so that the act of swivelling round
the carriages in the manner just described somewhat tilts the implement, and lifts
the digging tools which are at the centre of the implement clear of the ground, the
tools of the end carriages are also lifted clear of the ground. When all of them
have been raised the whole weight of the implement rests on the four end wheels.
One pair of end wheels can then be driven by gearing from the engine to move the
implement from place to place, whilst the other pair of wheels at the opposite end
of the implement may be used for steering.
In order to control the amount of forward and backward movement given to
each of the propelling legs when the implement is at work, each fulcrum is inde-
pendent and moves up and down with the legs, while at the same time the leg
can be rocked upon it. A screw is fixed on each leg to which the fulcrum is
attached by a nut working on the said screw, which nut can be turned by hand or
otherwise.
When it is desired that the spits of land turned over by the spades, forks, or
tines should be divided into short lengths, I in some cases effect this by forming
each tine, spade, or fork with a broad chisel edge at right angles with the face of
each tine or spade, so that at every penetration of the tines or forks the land is cut
in the direction the machine is moving or at right angles to the work already
done.
To allow of the digging tools entering the ground vertically or at any desired
angle, and to cause them as they leave the ground to throw over the spit of earth
in rear of them, I connect the stems of each fork or spade to the upper part of the
leg which works it, or to other part of the machine by an expanding spring link.
This link I form, by preference, of a rod jointed to the leg or other part of the
machine and having a steel spring coiled around it; at the extremity of the rod is
a head against which one end of the spring bears. To the stem of the forks or
spades is jointed one end of a tube. The rod with the coiled spring around it
passes into the other end of the tube, and an end cover is then screwed into this
end of the tube, and caused to compress the spring within it.
As the fork or spade enters the ground the link expands or contracts, thereby
allowing the tools to enter in a straight line until a stop comes into play, which

page_text: Figure 1 is a side elevation of a digging machine in which the digging tools are
when at work ranged along one of the longer sides of the implement, and which is
forined with pivotting end frames or carriages as herein before described. In this
figure one of the end carriages is turned into position for road travelling, the other
frame is in position for digging. Figure 2 is an end view of the same with the
digging tools in position for digging.
A is an ordinary tubular boiler having a funnel or chimney at each end and
central fire box A¹, so that the top of the fire box shall not be uncovered with
water when working on a hill side. It is also advisable to arrange that the
exhaust steam from the engine shall issue from whichever funnel is the lower.
B is the crank shaft of a steam engine mounted upon the boiler as shewn. From
this shaft motion is given by intermediate gear to the digger shaft C; on this
shaft are eccentrics D carrying the legs and feet E, to which are attached the fork
heads F by the rocking beams G. H are spring links constructed as herein before
described; one end of each link is connected to the upper end of the stein of one
of the digging tools; and the other to the upper part of the leg E by which this
tool is carried. One of the links is shewn in section at Figure 1; H' is the stop;
and H2 an india rubber or other clastic pad to stop jar when the spring is suddenly
liberated.
Projecting downwards from the boiler A are fixed pivots or drums A", one near
each of its ends for the end frames or carriages to turn on. These pivots are set at
an angle as shewn at Figure 2, so that when the end carriages have each a quarter
turn given to them so as to shift them into position for road travelling, the boiler
and frame of the implement are tilted so as to lift the central set of propelling legs
and digging tools carried by it clear of the ground, and also to lift up the tools
and propelling legs carried by the end carriages.
When a quarter turn has been given to each end carriage the machine rests upon
the wheels only two at each end.
The tilting over of the frame and boiler of the implement when the end carriages
are brought into position for road travelling as above described, also brings the
weight of the implement more uniformly upon all the wheels than would be the case
if the boiler and frame were not thus tilted over.

page_text: In order that the end frames or carriages may be readily turned, I fix to each of
them a toothed are concentric with and at right angles to its pivot, into which arc
is geared a pinion or worm, which is carried by the frame of the machine, so that
by turning the pinion or worm the end frame can be caused to swivel around its
pivot. The arcs and pinions or worms for turning them are not shown in the
Drawings. When the end frames or carriages are turned into position for road
travelling the wheels of one carriage come into position to be driven by gearing
from the crank shaft of the engine. Any ordinary arrangement of gearing such as
is used in traction engines may be employed for the purpose, so that I have not
thought it necessary to shew in the Drawings any arrangement of gear for driving
the wheels. When the end carriages are turned into position for the digging tools
to be set to work, the lengths of the shaft C on the two end carriages are coupled
by any suitable couplings with the length of the shaft C which is carried by the
boiler; these couplings also are not shown in the Drawings.
I would state that it is not essential that the pivots of the end carriages should
be inclined as vertical pivots might be used, nor is it essential that the locking
carriages should carry any of the digging tools, as means might be provided for
lifting the digging tools clear of the ground, independently of the turning of the
locking carriages.
At Figures 1 and 2 is also shewn the manner herein before described for
controlling the amount of backward and forward movement given to the propelling
legs when the implement is at work. The pivots as will be seen project from
blocks, which can be caused to slide up or down the legs. Each leg carries a
screw; this screw may be fixed and a nut carried by the block, but free to be
turned, may screw on the screw as shewn, so that by turning the nut by hand or
otherwise the pivots of the leg may be raised or lowered. Or the screw might
turn and engage with a screw thread in the block.
The small amount of steering which the implement requires when at work, I
prefer to effect by applying a break to the wheels at one or other end of the
implement, so as to retard this end of the implement and cause the implement to
turn.
At Figure 3, I have shewn a revolving digger constructed in the manner herein-
before described.
In this machine the diggers are mounted at one end of the machine, similar
arrangements of digging mechanism might however if desired be arranged along
one of the longer sides of a machine caused to travel sidewise over the land when
digging.
The digging mechanism consists of a shaft which may be driven from the engine
in any suitable manner; on the shaft are discs or wheels to which are jointed the
stems of the digging tools; the stems of these tools are also connected by springs
to the discs or wheels, which springs tend to draw or force the tools inwards
towards the shaft, but when as the shaft revolves the tools enter the ground the
spring is compressed or extended, and allows the tool to move away from the shaft
and enter downwards into the ground in a straight line without being dragged
through it in the line of travel of the implement. When the stem of the tool is
stopped from turning by any suitable stop the tool is then again carried round
with the revolving shaft, and turns over the spit of earth in rear of the tool, and
as the spit of earth gets turned over the spring expands or contracts, and brings
the digging tool back to its normal position.
I prefer to use a spring link constructed in the manner shewn at Figure 3* for
coupling the ends of the stems of the digging tools with the disca or wheels on the
shaft, but springs and stops may be otherwise used in connection with the stems
of the tools to effect the same object.
Figure 4 shews another arrangement of digging machine in which springs and
stops are used as herein before described to permit the tools to pass downwards in
a straight line into the ground, and to then cause the spits of earth to be turned
and thrown over backwards by the tools. In this case spring links, such as shewn

page_text: at Figure 3*, are used for connecting the upper ends of the stems of the tools to
the frame of the implement, and the tools are moved up and down by eccentrics or
cranks C¹ on a shaft C driven from the engine, as in the arrangement shewn at
Figures 1 and 2.
The machine is also provided with locking end carriages and wheels, as shewn
in those Figures. When the machine is at work the locking carriages are turned,
so that the wheels are ranged along the opposite side of the implement to that on
which the shaft C is carried, and when in this position are geared with the crank
shaft of the engine or the shaft C, and so give the requisite travel to the
implement.
The machine when at work is supported on the side opposite to these driven
wheels by revolving discs or harrows K mounted on a shaft K', the end parts of
this shaft as also the end sets of the digging tools may be carried by arms pro-
jecting from the end pivotting carriages, so that when the pivotting carriages are
turned into position for road travelling, these parts of the shaft and the harrows
carried by it are moved to the ends of the machine. In this case the machine
when at work may be steered by applying breaks to one or other of the wheels.
The harrows might if desired be revolved by gearing from the engine, but in
most cases this is unnecessary.
Figures 6 and 7 shew a similar arrangement of machine, except that the digging
tools are at one end of the implement, and the boiler is a horizontal instead of a
vertical one; the axis also of the discs or barrows is made to project from a vertical
pivot which can turn in bearings in the frame of the implement, whilst the outer
end of the axis can be moved towards or away from the body of the implement by
winding up or unwinding a chain by which the two are connected together as
shewn, so that the machine may be steered by causing the axis of the harrows to
incline more or less to the machine, or other means might be adopted for turning
the axis of the discs or harrow on its vertical pivot so as to steer the implement.
At Figure 5, I have shewn an end view of a tine or spade made as hereinbefore
described with a blade extending back in rear of it to cut the land at right angles
to the line of travel of the implement.
Having thus described the nature of my Invention and the manner of performing
the same, I would have it understood that I claim,-
First. The construction of digging machines (in which the digging tools when
digging are ranged along one side of the implement) with end pivotting carriages
each provided with rollers or wheels, which when the implement is at work are
ranged along and support the opposite side of the implement to that along which
the digging tools are ranged, and when the machine is required to be moved end-
wise when out of work, are by turning the locking carriages brought into position
for then supporting both sides of the implement, and for allowing the machine to
travel end wise.
Second. The construction of such machines with supporting rollers or wheels
on one side of the locking carriages and some of the digging tools on the opposite
side of such carriages, so that these tools are brought crosswise of the machine
when the locking carriages are turned into position for road travelling.
Third. Setting the pivots of the pivotting carriages of such machines in an
inclined position, so that the boiler and frame of the machine are tilted and the
digging tools lifted from the ground when the locking carriages are turned into
position for road travelling.
Fourth. The arrangements of mechanism herein before described for controlling
the amount of backward and forward movement given to the propelling legs of
such digging machines as are propelled by legs.
Fifth. The employment of a spring link and stops, substantially as herein before
described for controlling the movement of the digging tools of digging machines to
allow of the tools entering the ground in a straight line, and afterwards to cause
the digging tools to detach and jerk over the spits of earth in rear of them.
Sixth. The construction of the spades, tines, or forks of digging machines with

page_text: cutting blades extending from them at the back to cross cut the spits of earth,
which are next to be turned over by the spades, tines, or forks.
Seventh. The construction of revolving diggers, substantially as herein before
described with springs and stops for controlling the action of the digging tools to
allow of the tools entering the ground in a straight line, and afterwards to cause
the digging tools to detach and jerk over the spits of earth in rear of them.
Eighth. The combination with a digging machine of revolving tines or harrows,
which serve as a support to one side or end of the machine when at work, and act
upon the land after it has been turned over by the digging tools so as to divide or
pulverize it.
Ninth. The combination with a digging machine of revolving tines or harrows
in the above manner, and which serve also as a means for steering the machine as
herein before described.
Tenth. The construction of digging machines, substantially as herein before
described,
In witness whereof, I, the said Thomas Churchman Darby, have hereunto
set my hand and seal, this First day of November, in the year of our Lord
One thousand eight hundred and seventy nine.
T. C. DARBY. (LS.)