IMPROVEMENTS IN TUNNELLING AND ROCK BORING MACHINERY, PART OF THE INVENTION BEING ALSO APPLICABLE TO OTHER PURPOSES
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by the said Frederick Bernard Doering
at the Office of the Commissioners of Patents on the 27th September 1881.
FREDERICK BERNARD DŒERING, of Trefriw, North Wales, Civil Engineer.
"IMPROVEMENTS IN TUNNELLING AND ROCK BORING MACHINERY, PART OF THE
INVENTION BEING ALSO APPLICABLE TO OTHER PURPOSES."
In constructing tunnelling machines according to my Invention, I mount by
means of brackets or otherwise a series of rock boring machines or drills, say 4,
more or less, around a central boring machine or drill which is carried at the end
of an arm preferably consisting of a strong steel tube.
This steel tube, which is accurately turned on its outer surface, is supported by
one, two, or more accurately bored castings, which are carried on a strong frame work
mounted on wheels. Each of these castings is fitted with suitable means, such as
a hydraulic ram or screw, for wedging or fixing the machine against the roof and
floor or sides of the tunnel. The steel tube or arm carrying the boring machines
is capable of being slowly moved round on its axis, and this motion may be
obtained with advantage by means of a worm wheel and worm attached to one of
the castings, and a key on the worm wheel taking into a slot in the tube. At the
back portion of the tube a screw takes into a nut which is rigidly attached to the
tube, and by means of this nut the tube with the boring machines or drills thereon
is advanced as required.
The boring machines or drills are either fitted with crossheads carrying chisels,
or they have a single chisel attached with or without a cross head. The drills
The
strike and rotate a portion of a circle with each stroke in the usual manner.
centre drill is fixed rigidly in the tube; the four outer ones are fixed on a pivot so

page_text: that they can be turned outwards when required to increase the size of the
heading, which may have become reduced through the wear on the outside edge of
the chisels.
In order to bore a circular tunnel the outer drills are all made the same size, and
bore or chip away equal areas, and their centres are all the same distance from the
centre of the carrying tube or arm. As the tube or arm is made to revolve slowly,
cach boring machine striking and turning in the usual manner, it is apparent that
a circular tunnel will be chipped out by this means. If however it is desired to
make an oval shaped heading, which is generally preferred, as requiring the romoval
of less material, the machines boring on the shorter axis of the oval are made
smaller, bore smaller areas, and their centres are closer to the centre of the carrying
arm than the machines working on the longer axis. The battery of drills in the
case of oval headings is made to move through only a portion of an arc instead of
a whole circle. When the carrying tube with the machines or drills on it has
through the medium of the worm and worm wheel been made to move to the limit
of the are on one side, it is slowly moved back again and to the same distance on
the other side, and so on backwards and forwards. An oval tunnel or heading is
thus cut out. Although in most cases it will be preferable to have a central boring
machine, as above explained, it is not necessary. For example, there may be two
boring machines placed at opposite sides of the centre, and 4 or other number of
other machines placed outside these two.
of
When a twisted bar inserted in the back of a piston of a rock drill or boring
machine is employed to effect the requisite turning of the boring tool, the power
the piston to turn the twist bar on the reverse stroke is dependent upon the
friction and inertia of the piston exceeding the friction and inertia resisting the
turning of the twist bar. This requires nice adjustment which is easily disturbed.
To make the turning of the tool a certainty I insert a second bar, which I will call
a check bar, into the back of the piston, not in the centre, but parallel to it; this is
cast in one piece with a crank and a shell or hollow shaft, fitting over and
concentric with the boss of the twist bar; a ratchet wheel is attached to this shell
and a paul takes into it. The twist bar has a ratchet wheel attached to its outer
end into which a paul takes to prevent backturning, as when used singly. When
the piston moves forward (or, if preferred, when it moves back ward) it is by
means of the straight bar, crank, and ratchet prevented from sliding on the grooves
on the twist bar without turning it, and consequently turns the twist bar. The
twist bar is now held in its new position by the ratchet and paul at the back of it.
On the return stroke of the piston it slides on the grooves of the twist bar without
turning the twist bar. The piston itself turns, as also the check bar, and the paul
attached to the check bar takes into a fresh tooth and prevents the piston and
check bar turning in a reverse direction on the next stroke.
In order to dispense with long air passages from the valve to the two ends of
the cylinder of the boring machine, I place a piston valve at each end of the
cylinder. Each valve has a central supply chamber in constant communication
with the air compressor or source of compressed air. The supply and exhaust of
the air to either end of the cylinder is effected by cach valve alternately enclosing
within its supply chamber an opening in the side of the main cylinder at right
angles to its axis, and then exposing this opening to the atmosphere. In order to
enable the spring packing rings of the piston valves to slide over the openings
before mentioned, which are at the ends of the main cylinder, and which exceed in
width the width of the spring packing rings, I chamber out a channel in the valve
casings all round internally opposite the passages into the cylinder ends, and fix
liners into the valve casings with holes perforated therein directly opposite the
channels, and which lead to the passages into the cylinder ends.
$
Hitherto it has been my practice to insert the piston into the advance cylinder
(that is to say, the cylinder which effects the gradual advance of the tool) from the
front or working end, which involves the attachment of a gland or cover through
which the piston rod passes. This gland is difficult to pack and forms a bad guide

page_text: for the piston rod of the advance cylinder, the result being loss of air through
leakage. To overcome this objection I now pass the piston and rod into the
cylinder through the back end, and insert a liner to hold the packing in position ;
and in order that the liner may be easily removed, I make it in one with or
otherwise attach it to the cylinder cover.
After the pressure of air has been exhausted from the back of the piston of the
advance cylinder, this piston and its paul may be brought back by means of a long
spiral spring.
In compressing the air for the boring machines or drills, it has been usual for
the air to enter the inlet valve of the compressor at the ordinary atmospheric
pressure. As a feeble pressure, say, up to 7 pounds above the atmosphere, more or
less, can be produced moro simply, and at a less first cost of apparatus by a steam
or other blower, I employ a blower for the first stages, with a compressing pump
for the latter stages of compression; I can thus reduce the size of the compressing
cylinder and still obtain the same results, and increase the capacity of existing
compressors at a moderate outlay.
For this purpose I cast or otherwise attach casings over the inlet valves of the
compressor, and connect these casings by suitable pipes to an air receiver, which I
fill with compressed air at a low pressure by means of the blower. When the steam
blowers-are-used-I-pass_the_air and steam through a cooling condenser in order to
precipitate the water. The condenser may be placed inside or outside-the-receiver.
When the inlet valves are in the piston-and-the-air-is-taken in through a hollow
tail piston rod, a hollow guard or cover is placed over this rod with a flange for
connecting to a receiver as in the previous case. The air compressor communicates
with the supply valves of the bering machine cylinders, as is understood.
Although this improved arrangement has been especially designed for producing
the necessary compressed air for my improved tunnelling and rock boring machines,
it can be employed for compressing air for other purposes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Frederick Bernard Doering in the Great Seal Patent Office on
the 27th March 1882.
FREDERICK BERNARD DOERING, of Trefriw, North Wales, Civil Engineer.
"IMPROVEMENTS IN TUNNELLING AND ROCK BORING MACHINERY, PART OF THE
INVENTION BEING ALSO APPLICABLE TO OTHER PURPOSES."
In constructing tunnelling machines according to my Invention I mount, by
means of brackets or otherwise, a series of rock boring machines or drills, say 4,
more or less, around a central boring machine or drill which is carried at the end
of an arm, preferably consisting of a strong steel cylinder.
This steel cylinder, which is accurately turned on its outer surface, is supported
by one, two, or more accurately bored castings which are carried on a strong frame-
work mounted on wheels. Each of these castings is fitted with suitable means,
such as a hydraulic ram or screw for wedging or fixing the machine against the
roof and floor or sides of the tunnel. The steel cylinder or arm carrying the
boring machines is capable of being slowly moved round on its axis, and this
motion may be obtained with advantage by means of a worm wheel and worm
attached to one of the castings, and a key on the worm wheel taking into a slot
in the cylinder. At the back portion of the cylinder a screw takes into a nut
which is rigidly attached to the cylinder, and by means of this nut the cylinder
with the boring machines or drills thereon is advanced as required.
The boring machines or drills may be either fitted with crossheads carrying
chisels, or they may have a single chisel attached with or without a crosshead.
The drills strike and rotate a portion of a circle with each stroke in the usual
manner. The centre drill is fixed rigidly in the cylinder; the four outer ones are
fixed on a pivot, so that they can be turned outwards when required to increase
the size of the heading, which may have become reduced through the wear on the
outside edge of the chisels.
In order to bore a circular tunnel the outer drills are all made the same size, and
bore or chip away equal areas, and their centres are all the same distance from
the centre of the carrying cylinder or arm. It is apparent that as the cylinder is
made to revolve slowly, each boring machine striking and turning in the usual
manner, a circular tunnel will be chipped out by this means. If however it is
desired to make an oval shaped heading, which is generally preferred as requiring
the removal of less material, the machines boring on the shorter axis of the oval
are made smaller, bore smaller areas, and their centres are closer to the centre of
the carrying arm than the machines working on the longer axis. The battery of
drills in the case of oval headings is made to move through only a portion of an
arc instead of a whole circle. When the carrying cylinder with the machines or
drills on it has, through the medium of the worm and worm wheel, been made to
move to the limit of the are on one side it is slowly moved back again, and to the
same distance on the other side, and so on backwards and forwards. An oval
tunnel or heading is thus cut out. Although in most cases it will be preferable
to have a central boring machine, as above explained, it is not necessary.
For
example, there may be two boring machines placed at opposite sides of the centre,
and four or other number of other machines placed outside these two.
Figures 1 and 2 represent a tunnelling machine constructed according to my
Invention, Figure 1 being a side elevation partly in section, and Figure 2 a view
of the front or working end.
A is a cylinder of steel or other material serving as a shaft, to which the
brackets B, B, B, B, are attached, forming a crosshead on the shaft A. Each of
these brackets supports a rock-drill cylinder C, C, C, C, each carrying a piston and

page_text: Those
boring tool with the usual arrangement for working the valve and turning tho
tool, but dispensing in most cases with the self acting advance motion.
cylinders are pivotted on the brackets at E, E, E, E, and are held in their required
positions by clamping screws, as shewn at F, F.
In a line with the centre axis of the cylinder or shaft A a rock-drill is also
placed and suitably attached to a projecting portion of the shaft A as shown. The
shaft A is supported and guided by the castings G, G, on the upper side of which
hydraulic cylinders and rams H, H, aro fixed, while the lower side is supported
by a carriage frame. If found necessary these hydraulic cylinders might be placed
in a horizontal position on each side of the supporting castings and increased in
number. A worm wheel I and worm K are attached to one of the castings G, and
a key L on the worm wheel I takes into a slot M on the shaft A, so that when the
worm K revolves the shaft A revolves also. At the binder part of the carriage
frame a bracket N carries a screw O which takes into a nut P in the shaft A, so
that when this screw O is turned by means of the wheel or handle Q, the shaft A,
with crosshead and drills, is made to advance or recede. The rock-drill pistons
have suitable cutters attached to them.
The Figures shew a machine arranged for boring an oval or oblong tunnel, i.c,
less in its width than in its height; this form is obtained by making the horizontal
arm of the crosshead shorter than the vertical arın, and placing the contres of the
rock-drills-on-this-horizontal-arm-closer-to-the_shaft A than the centres of the
-drills_on_the_longer_vertical arm; it is apparent also that the drills on the shorter
arm bore away sinaller areas than the drills on the longer arm. It is not-necessary-
that each bracket should be confined to carrying only one drill; according to the
size of the heading I may increase the number and size of the drills, as may bo
required. By means of the worm K and worm wheel I the centres of the drills
carried by the arms forming the crosshead can be moved through the arcs 20, x, y,
and, and by doing so slowly, the drills at the same time, striking and turning a
portion of a circle, will bore out a heading, as shewn in the Drawing. Where a
circular tunnel is required the vertical and horizontal arms are made the same
length, and the drills on each placed the same distance from the centre revolving
shaft carrying the drills, and if required a greater number of arms and drills may
be attached to the shaft A than are shewn in the Drawing, for instance, when
large tunnels or headings are to be bored.
I do not limit ny Invention to machinery for cutting horizontal tunnels or
headings; it may be arranged for cutting on an incline or vertical. In the latter
case it would probably be necessary to support the steel or iron castings guiding
the shaft A on two or more sides by an iron framing, to which framing suitable
attachments could be made for raising or lowering the machine. Further, instead
of a screw for advancing the shaft A a hydraulic piston or other suitable known
appliance may be employed. It would also be necessary to fix the frame
carrying the whole apparatus at several points by means of screws or hydraulie
rams.
In using this machine for shaft sinking, it may be necessary to make the centre
drill removable and independent of the other drills and crossheads, so as to be able
to bore in advance of the others, and to withdraw the drill (the shaft A being
suspended from its exterior surface instead of from the centre) so as to allow the
debris to be extracted from this hole by means of a sand pump or other appliance.
I claim under the part of my Invention herein before described,-
First. Constructing tunnelling machinery with a series of rock drills or boring
machines attached to a crosshead or brackets on a shaft or cylinder, which can be
made to turn on its axis, substantially as herein before described and represented in
the accompanying Drawings.
Second. In tunnelling machinery constructed in the manner referred to in the
first claim, I claim the use of a crosshead with one shorter axis and one longer one
as described, so as to bore oval or oblong tunnels or headings.
Third. The combination or arrangement of parts forming improved tunnelling

page_text: machinery, substantially as herein before described and represented in the accoin-
panying Drawings.
The next part of my Invention has reference to rock-drills or boring machines.
When a twisted bar inserted in the back of the piston of a röck-drill or boring
machine is employed to effect the requisite turning of the boring tool, the power of
the piston to turn the twist bar on the reverse stroke is dependent upon the friction
and inertia of the piston exceeding the friction and inertia resisting the turning of
the twist bar. This requires nice adjustment which is easily disturbed. To make
the turning of the tool à certainty I insert a second bar, which I will call a check
bar, into the back of the piston, not in the centre, but parallel to it; this is cast in
one piece with a crank and a shell or hollow shaft fitting over and concentric with
the boss of the twist bar; a ratchet wheel is attached to this shell, and a paul takes
into it. The twist bar has a ratchet wheel attached to its outer end, into which n
paul takes to prevent back turning, as when used singly. When the piston moves
forwards (or if preferred when it moves backwards), it is by means of the straight
bar, crank, and ratchet prevented from sliding on the grooves of the twist bar
without turning it, and consequently turns the twist bar.
The twist bar is now held in its new position by the ratchet and paul at the back
of it. On the return stroke of the piston it slides on the grooves of the twist bar
without turning the twist bar. The piston itself turns, as also the check bar, and
the paul attached to the check bar takes into a fresh tooth and prevents the piston
and check bar turning in a reverse direction on the next stroke.
In order to dispense with long air passages from the valve to the two ends of the
cylinder of the boring machine, I place a piston valve at each end of the cylinder.
Each valve has a central supply chamber in constant communication with the air
compressor or source of compressed air. The supply and exhaust of the air to
either end of the cylinder are effected by each valve alternately, enclosing within
its supply chamber an opening in the side of the main cylinder at right angles to
its axis, and then exposing this opening to the atmosphere. I connect the two valves
to each other by a rod which will serve as a handle or means of reversing and
starting the drill by hand in case of need. In order to enable the spring packing
rings of the piston valves to slide over the openings before mentioned, which are at
the ends of the main cylinder, and which exceed in width the width of the spring
packing rings, I chamber out a channel in the valve casings all round internally,
opposite the passages into the cylinder ends, and fix liners into the valve casings
with holes perforated therein directly opposite the channels, and which lead to the
passages into the cylinder ends. This arrangement is specially adapted for use
with compressed air, which being an expensive motor to produce, renders it
important to dispense with the loss occasioned by the use of long passages which
exist where the ordinary valve arrangements are employed. It also allows of the
port of the advance cylinder (which exhausts into the main cylinder) being placed
nearer to the end of the stroke of the hinder part of the main piston; the advantage
of this is that as the advance cylinder can be exhausted more quickly, the difference
of feed with a low pressure and a high pressure is not so great as when the inain
exhaust has to travel through a long passage, the tendency being with a high
pressure for the advance cylinder to exhaust, and thereby put itself into position
to work at a later period of the stroke of the main piston than with a low
pressure; a quicker exhaust reduces this tendency.
Hitherto it has been my practice to insert the piston into the advance cylinder
(that is to say, the cylinder which effects the gradual advance of the tool) from tho
front or working end which involves the attachment of a gland or cover through
which the piston rod passes. This gland is difficult to pack, and forms a bad guirle
for the piston rod of the advanced cylinder, the result being loss of air through
leakage. To overcome this objection I now pass the piston and rod into the
cylinder through the back end and insert a liner to hold the packing in position;
and in order that the liner may be easily removed I make it in one with or other-
wise attach it to the cylinder cover;

page_text: After the pressure of air has been exhausted from the back of the piston of the
advance cylinder, this piston and its paul may be brought back by means of a long
spiral spring.
Figure 3 is a longitudinal section; Figure 4 a transverse section, and Figure
an end view of a rock drill or boring machine embodying my improvements as
above described.
A is the twist bar with spiral grooves fitting into a bush in the back and centro
portions of the rock drill piston B and ordinarily used for giving the necessary
turning motion to the percussion drill. To the end of this bar outside of the
cylinder cover is fixed the usual toothed wheel C, into which a paul V takes to
prevent the turning of the bar when the piston is being turned by sliding on the
spiral grooves on the bar A; D is the other bar (which I have herein before called
the check bar) without spiral grooves taking into a hole in the the piston B
parallel to the central hole in which the twist bar works. This bar D is rigidly
attached by means of the crank E to the hollow shell F, fitting close to and
concentric with the back portion of the bar A. Where the shell passes outside
of the cylinder cover a ratchet wheel a is rigidly fastened, into which a
paul U takes to prevent the piston turning in any but one direction. It is
evident that when the piston makes its forward stroke it has a tendency to
move in the direction shewn by the spiral grooves on A, but is prevented doing so
by the straight bar D which held by the paul U taking into the wheel G, the
central spiral twist bar is therefore compelled to move in a direction from left to
right. The piston B on the return stroke is free to move in the direction indicated
by the spiral on A, and as it cannot turn the twist bar in a direction from right to
left it is compelled to turn from left to right. By this arrangement for every
double stroke of the piston the piston must turn a portion of a circle on the
forward stroke, the twist bar being turned, and on the back stroke the piston and
check bar turning. By reversing the position of the pauls and teeth of the ratchet
wheels, the piston would turn in the reverse direction and on the forward stroke..
H, H, are valve boxes placed at each end of the rock drill cylinder; H¹, H', are
the valves, and H is a rod which connects them as before described; I, I, are liners
in the valve cylinder; K, K, are recesses in the valve casing round the liners;
L, L, are perforations in the liners made of such a size as to allow the valve piston
rings to pass over without catching. The short passages M, M, at the ends of the
cylinder communicate directly with the main supply which enters the valve
chamber at N, N, and when the valve is reversed the exhaust takes place directly
into the atmosphere.
O is the advance cylinder; O', the piston, and P the piston rod for actuating the
advance nut T; Q, Q, are the ring packings and glands; R is a linor holding the
piston rod packing in its place, and rigidly fixed to the back cover; S is a rubber
buffer placed in the cover to receive the blow of the advance piston on the back
stroke.
I claim as improvements in rock drills or boring machines,―
First. The combination with the twist bar of a second or check bar and other
parts for the purpose of effecting the turning of the tool with certainty, sub-
stantially as hereinbefore described and represented in Figures 3, 4, and 5 of the.
accompanying Drawings.
Second. Constructing rock drills or boring machines with a piston valve at
each end of the cylinder, and with a port at each end at right angles to the
cylinder, the supply of the motive fluid to the ends of the cylinder and the exhaust
therefrom taking place in the manner set forth, and the valve casings having
chaunels and perforated liners, all substantially as and for the purposes hereinbefore
described and represented in Figure 3 of the accompanying Drawings.
Third. The packing of the piston rod gland of the advance cylinder from the
back end of the cylinder, and securing the packing in place by the cylinder
liner, substantially as hereinbefore described and represented in Figure 4 of the
accompanying Drawings,
.

page_text: The next part of my Invention has reference to air compressors for compressing
the air for the rock drills or boring machines.
In compressing the air for this purpose, it has been usual for the air to enter the
inlet valve of the compressor at the ordinary atmospheric pressure. As a feeble
pressure, say up to seven pounds above the atmosphere more or less, can be produced
more simply and at a less first cost of apparatus by a steam or other blower, I
employ a blower for the first stages with a compressing pump for the latter stages
of compression. I can thus reduce the size of the compressing cylinder and still
obtain the same results and increase the capacity of existing compressors at a
moderate outlay.
For this purpose I cast or otherwise attach casings over the inlet valves of the
compressor, and connect these casings by suitable pipes to an air receiver which I
fill with compressed air at a low pressure by means of the blower. Where steam
blowers are used I pass the air and steam through a cooling condenser in order to
precipitate the water. The condenser may be placed inside or outside the receiver.
When the inlet valves are in the piston and the air is taken in through a hollow
tail piston rod, a hollow guard or cover is placed over this rod with a flange for
connecting to a receiver as in the previous case. The air compressor communicates
with the supply valves of the boring machine cylinders, as is understood.
Although this improved arrangement has been especially designed for producing
the necessary compressed air for my improved tunnelling and rock boring machines,
it can be employed for compressing air for other purposes.
Figure 6 represents my improved arrangement of apparatus-for-compressing-air-;-
A is a Körting's or other suitable-blower-which-blows.air into a receiver B; if a steam
blower be used I employ a cooling condenser inside or outside this receiver in order
to precipitate the water; C is a pipe leading from the receiver B and terminating
in a breeches pipe D. The two legs or branches of this pipe communicate
respectively with inlet casings E, E, over the inlet valves F of the air compressor G;
H is one of the delivery valves.
I claim under this part of my Invention,―
3
The combination with air compressors (for compressing air for tunnelling or rock
boring machinery or other purposes) of a blower and an intermediate receiver in
communication with casings over the inlet valves of the compressor, so that the
con pressing cylinder shall receive the charge of air to be compressed at a higher
pressure than that of the atmosphere, substantially as herein before described and 3
represented in Figure 6 of the accompanying Drawings.
In witness whereof, I, the said Frederick Bernard Deering, have hercunto
set my hand and seal, this Twenty fifth day of March, One thousand
eight hundred and eighty two.
F. B. DŒRING. (L.S.)