IMPROVEMENTS IN MOTIVE- POWER, AIR-COMPRESSING, ROCK-BORING, AND OTHER APPARATUS TO BE USED IN QUARRYING AND MINING, AND ALSO IN PART APPLICABLE FOR OTHER PURPOSES
Year: 1876

page_text: LETTERS PATENT to Graham Stevenson, of Airdrie, in the County of Lanark,
North Britain, Engineer, for the Invention of "IMPROVEMENTS IN MOTIVE-
POWER, AIR-COMPRESSING, ROCK-BORING, AND OTHER APPARATUS TO BE
USED IN QUARRYING AND MINING, AND ALSO IN PART APPLICABLE FOR
OTHER PURPOSES."
Sealed the 1st September 1876, and dated the 2nd March 1876.
PROVISIONAL SPECIFICATION left by the said Graham Stevenson at the
Office of the Commissioners of Patents on the 2nd March 1876.
GRAHAM STEVENSON, of Airdrie, in the County of Lanark, North Britain
Engineer. "IMPROVEMENTS IN MOTIVE-POWER, AIR-COMPRESSING, ROCK-BORING
AND OTHER APPARATUS TO BE USED IN QUARRYING AND MINING, AND ALSO IN
PART APPLICABLE FOR OTHER PURPOSES."
This Invention comprises various improvements in machinery specially designed
for quarrying and mining, and is partly a development of the Invention described in
the Specification of Letters Patent obtained by the present applicant and dated
3 February 1875 (No. 387).
An important part of the present Invention relates to improved rock-boring and
coal-cutting apparatus to be worked by compressed air, and requiring motive-power
and air-compressing apparatus specially adapted for quarrying and mining opera-
tions, and having the parts simple and suited for rough and severe work, and not
liable to rapid wear or to get easily out of order.
The first part of the Invention relates to motive-power and air-compressing
apparatus, and comprises an arrangement in which a bed piece cast in a hollow
form to serve as a receiver for the compressed air has set over one end of it a pair
of steam cylinders, whilst a similar pair of air-compressing cylinders are set over
the other end, a horizontal crank shaft extending between the two with a fly wheel
on the middle of it. The two steam cylinders, which are single acting, are inclined
to each other so that a cylindrical valve chamber with a single oscillating valve is
conveniently got between their outer ends, and their lower ends open into a circular
chamber in which the cranks revolve. The cranks are at such an inclination to
each other as with the inclination of the cylinders to cause the two pistons to be
always at opposite parts of their strokes, and the connecting rods are jointed
directly to the pistons. The air cylinders are similarly placed and connected, and
the air enters their outer ends through spring valves, and passes through spring
[Price 10d.]

page_text: valves in the pistons to the closed space in which the cranks work, and thence into
the receiver. Or the valves may be arranged to act in the reverse way, in which
case the packing details of the piston may be fitted to a ring which is movable
relatively to the piston body to which the rod is jointed, and which ring closes or
opens a passage or passages through the piston accordingly as the piston moves in
one direction or the other.
In a modified arrangement the horizontal crank shaft is placed across the air
receiver, and is driven by two single-acting or double-acting steam cylinders set
horizontally on the air receiver, and each having an air compressing cylinder placed
in the same line and worked by the same piston rod.
In another arrangement three single-acting steam cylinders are placed at equal.
angles round a crank shaft, one of them being by preference vertical and their
inner ends are open to a closed, chamber in which the crank works. Separate
radially moving slide valves worked by a single eccentric distribute the steam to
the cylinders, or this may be done by oscillating valves in cylindrical valve
chambers, also all worked by one eccentric. Or a single non-rotating valve may
serve all three cylinders, such valve being applied to a port face in the central space
which may be termed the crank chamber and in which the fresh steam will in that
case be admitted.
A somewhat similar arrangement may also be adopted for the air compressor, but
with three piston chambers of square section instead of cylinders, and with spring
blade valves of the kind described in the earlier Specification herein-before referred
to, in the pistons and in the outer ends of the cylinders. The square piston
chambers with the spring blade valves may be combined in any convenient number,
or a single one may be used.
The motive power arrangements with three cylinders herein-before described are
advantageously applicable for directly driving, drilling, or boring spindles and the
like.
The second part of the Invention relates to percussive rock-boring apparatus, and
comprises an arrangement in which the piston is formed on a long tubular rod,
through which the boring rod is passed, and in which the latter can be shifted to
any extent. The boring rod is fixed to the piston rod by pinching pins screwed
through an enlarged part of the piston rod and entering small notches formed for
then in the boring rod. The piston rod being formed with enlargements at both
ends, the cylinder is made with movable half ends and stuffing boxes, which can be
got into their places after the piston rod is in the cylinder. If the piston strikes
either end the packing in the gland acts as a cushion and moderates the concussion.
The cylinder is fitted to slide on its supporting guide frame, which is provided with
a clump for attaching it to a tube or spar, and a screw held by the guide frame feeds
the cylinder along by an automatic movement, being also capable of being turned
by hand, either separately or whilst the automatic motion is working. A kind of
head fitted on the piston rod carries a two-armed lever, to one arm of which there is
jointed a pawl acting on ratchet teeth formed on the piston rod, whilst to the other
arm there is jointed a link which has its end held in an oblique groove in a plate
attached to and moving forward with the cylinder. As the piston makes its stroke
the oblique groove causes the lever to turn the rod. The valve of the cylinder,
which is an oscillating one, is in a cylindrical chamber parallel to the main cylinder,
and is moved by a quick screw acted on by a part of the piston rod head, but play
is allowed between certain of the details so that the valve is moved only at or near
the ends of the strokes. The parts acting on the valve also act on the feed screw
through a lever, pawl, and ratchet-toothed, internally-screwed tube. The feeding
and turning levers are made adjustable so that the lengths of their strokes can be
varied to suit different cases.
When a boring is to be put down to a great depth the lengths of the boring rod
are jointed to each other, cach joint being fitted with a steel spring tending to keep
the connection rigid when opened out. The rod lengths jointed together in this
way can be wound upon a large polygonal drum when they have to be drawn up

page_text: out of the bore. The piston rod and cylinder may be made large enough for the
joints of the boring rod to pass through or the rod may be held outside of the
cylinder by clamps attaching it to the ends of the piston rod. Any kind of boring
rod may be held in this way outside of the cylinder when the cylinder cannot be
got quite in line with the position in which the boring is to be made.
Or two boring bars may be worked by one cylinder, the piston rod being in that
case arranged to actuate a rocking shaft fitted with levers at each side of the frame,
bracket, or standard to which the cylinder is fixed, and which carries the rocking
shaft and also a second rocking shaft having levers on it to serve as guides to the
upper or outer parts of the boring bars.
When the boring tool is to work by rotation without percussion the power is
transmitted by a wire or other rope to a pulley mounted in a frame which is fixed
to or held against the rock. The boring rod or spindle passes through the boss of
the pulley, and is fed forward by means of a parallel screw spindle which moves a
block engaging between collars or nuts on the spindle. The pulleys for the wire or
other driving rope are made each with a shallow grooved wooden tread or rim
connected to the boss or centre by light wrought-iron spokes, which are in pairs set
wider apart at the boss than at the rim, and which are fixed to the boss by rings
shrunk over segmental parts formed on their inner ends.
Pulleys constructed as last described are suitable for wire or other ropes of various
sizes up to the largest employed for inining purposes, and the spokes may be formed
with horns projecting beyond the rim to keep the rope in its place.
In quarrying, the boring apparatus has frequently to be applied upon the vertical
face of a rock, in which case whilst the apparatus may be conveniently suspended
from the overhanging arm of a derrick fixed at the top of the rock, it is desirable
to have a firm hold of the rock face to withstand the resistance to the boring action.
For this purpose holes are first bored a short distance into the rock, and each is
tapped to receive a screwed bar, or a bar to which a cast iron or other screw is
fixed, one or more horizontal bars are then fixed on the screw-held bars so as to be
parallel to the rock face, and the supporting and guiding frame of the boring
cylinder is clamped upon the parallel bar or bars.
Bore holes made for blasting rock are advantageously enlarged or under cut at
some distance in from the mouths of the holes. For effecting this enlargement a
rotating boring bar is used and is fitted with one or two cutters jointed within a
recess near the point and arranged so as to be turned outwards by means of a
wedge or of a worm moved. by means of a rod passing along the bar which is made
tubular for the purpose.
For cutting coal or similar minerals one or more rotating boring bars are used being
mounted in an improved manner. In one modification a single boring bar is held
with several bearings by a jib, which projects out laterally from a truck, or as is
preferred from a slide frame fitted with screw feed gear on a long guide frame. The
bar is armed with cutters at all possible points between the bearings, and a slow
reciprocating motion is imparted to the jib, so that the cutters may at one time
work at parts opposite to which the bearings have been at another time. The
boring bar cuts with its side, and is fed along the guide frame in a direction at right
angles to itself, and it is driven from the crank shaft of a small engine.worked by
compressed air, or from a pulley driven by a rope transmitting motive power from a
distance.
In another modification of the coal cutting apparatus four or other convenient
number of the rotating, boring or cutting bars are mounted upon a jib, which is
fixed to the slide frame or truck whilst working, although it can be turned when
required into any desired position. Each bar is armed with cutters near its outer
end, and the bars project to different distances, so that the least projecting one of
any adjacent two cuts in advance of the other in the direction in which the slide
frame or truck moves. The bars have bearings at their cutting parts, such bearings
being on blocks fitted to slide on guides formed for them on the jib; and the bars
are driven by means of pinions on them, two of them in one direction by one spur

page_text: wheel, and the other two in the opposite direction by a second spur wheel gearing
with the first. Reciprocating motions are imparted to all the bars by means of
oblique sides on the driving spur wheels acting between flanges on the pinions.
With the described arrangements the motions of one pair of bars are balanced by
the opposite motions of the other pair, and the machinery can consequently be
driven at a high speed with little vibration or concussion.
The winding, hauling, or power-transmitting ropes used in quarrying and mining
operations are by this Invention made to be more durable and flexible than the
steel ropes, commonly used. The plaiting or hard twisting together of the wires or
strands in ordinary steel ropes causes them to injure and cut each other and leads
to rapid wear, which is avoided in the improved rope by laying the main wires
close together with a long or very slight twist. In one modification a core of hemp
or other suitable compressible material has laid on it a sheath of closely placed
wires twisted very slightly in one direction, and outside of this a second sheath of
wires slightly twisted in the opposite direction is put. There may be more than
two sheaths or layers of strong wire, but outside of all there is by preference put a
skin of fine flexible wire plaited together.
SPECIFICATION filed in pursuance of the conditions of the Letters Patent, and of
an Order of the Lord Chancellor, by the said Graham Stevenson in the Great
Seal Patent Office on the 18th September 1870.
"
GRAHAM STEVENSON, of Airdrie, in the County of Lanark, North Britain,
Engineer. IMPROVEMENTS IN MOTIVE-POWER, AIR COMPRESSING, ROCK-BORING,
AND OTHER APPARATUS TO BE USED IN QUARRYING AND MINING, AND ALSO IN
PART APPLICABLE FOR OTHER PURPOSES."
My said Invention comprises various improvements in machinery specially
designed for quarrying and mining, and is partly a development of the Invention
described in the Specification of Letters Patent obtained by me and dated
February 1875 (No. 387.)
An important part of the present Invention relates to improved rock-boring and
coal-cutting apparatus to be worked by compressed air, and requiring motive-power
and air-compressing apparatus specially adapted for quarrying and mining opera-
tions, and having the parts simple and suited for rough and severe work, and not
liable to rapid wear or to get easily out of order.
And in order that my said Invention and the manner of performing the same
may be properly understood, I now proceed to particularly describe the same,
referring where it appears necessary to explanatory Drawings, of which I hereunto
append five Sheets.
The first part of my Invention relates to motive-power and air-compressing
apparatus, and comprises an arrangement shown in end and side elevation in
Figures 1 and 2 on Sheet 1 of the Drawings, in which arrangement a bed piece 1,
cast in a hollow form to serve as a receiver for the compressed air, has set over one
end of it a pair of steam cylinders 2, whilst a similar pair of air compressing
cylinders 3 are set over the other end, a horizontal crank shaft 4 extending between
the two with a fly wheel on the middle of it. The two steam cylinders 2, which
are shown in vertical section in Figure 3 and are single acting, are inclined to each
other so that a cylindrical valve chamber 5 with a single oscillating valve is
conveniently got between their outer ends, and their lower ends open into a circular
chamber 6, in which the cranks 7 revolve. The cranks 7 are at such an inclination
to each other as with the inclination of the cylinders 2 to cause the two pistons to
be always at opposite parts of their strokes, and the connecting rods are jointed
directly to the pistons. The air cylinders 3 are similarly placed and connected, and
the air enters their outer ends through spring valves 8, shown in section in Figure 4,
and passes through spring valves 9 in the pistons 10 to the closed space 6 in which

page_text: the cranks work, and thence into the receiver 1. Or the valves may be arranged to
act in the reverse way, in which case the packing details of the piston may be fitted
as shown in Figure 5, to a ring 11, which is movable relatively to the piston body
10 to which the rod is jointed, and which ring closes or opens a passage or passages
through the piston accordingly as the piston moves in one direction or the other.
In another arrangement three single-acting steam cylinders are placed at equal
angles round a crank shaft, as shown in vertical section in Figure 6, one of them
being by preference vertical, and their inner ends are open to a closed chamber 6,
in which the crank 12.works. Separate radially moving slide valves worked by a
single eccentric may be used to distribute the steam to the cylinders; or this may
be done as shown by oscillating valves in cylindrical valve chambers 13, also all
worked by one eccentric.
A similar arrangement may also be adopted for the air compressor, but with three
piston chambers of square section instead of cylinders, and with spring blade valves
of the kind described in the earlier Specification herein-before referred to, in the
pistons and in the outer ends of the cylinders. The square piston chambers with
the spring blade valves may be combined in any convenient number or a single one
may be used.
The motive power arrangements with three cylinders herein-before described are
advantageously applicable for directly driving, drilling, or boring spindles and the
like.
The second part of my Invention relates to percussive rock-boring apparatus, and
comprises an arrangement in which the piston 14 is formed on a long tubular rod 15,
through which the boring rod 16 is passed, and in which the latter can be shifted to
any extent.
This arrangement is shown on Sheet 2 of the Drawings, Figure 7 being
a longitudinal section, and Figure 8 a plan, whilst Figures 9, 10, and 11 show details.
The boring rod 16 is fixed to the piston rod 15 by pinching pins 17 screwed
through an enlarged part of the piston rod and entering small notches formed for
them in the boring rod. The piston rod 15 being formed with enlargements at
both ends, the cylinder 18 is made with movable half ends and stuffing boxes,
which can be got into their places after the piston rod is in the cylinder. If the
piston strikes either end the packing in the gland acts as a cushion and moderates
the concussion. The cylinder 18 is fitted to slide on its supporting guide frame 19,
which is provided with a clamp 20 for attaching it to a tube or spar, and a screw 21
held by the guide frame feeds the cylinder along by an automatic movement being
also capable of being turned by hand, either separately or whilst the automatic
motion is working. The piston rod 15 has formed on it an acutely grooved or
fluted head or enlargement 22, which during a part of the stroke works in contact
with a short grooved guide 23, shown in Figures 7 and 10, so as to prevent the
piston rod from turning, excepting when near the back end of its stroke. The back
end of the enlargement 22 is formed with acute radial grooves, and engages with a
tubular piece 24, the inner end of which is similarly grooved as the piston approaches
the back end of its stroke. The tubular piece 24 is externally of a helical form or
shaped like a quick screw, and is capable of a short longitudinal movement in a
helical guide socket 25. The piston rod is continued through the tubular piece 24 in
the form of a thin tube 26, having a collar 27 fixed on its back end, which collar moves
the tubular piece 24 inwards, whilst the grooved enlargement 22 moves it outwards,
but from the play between the parts doing so only during the latter parts of the
strokes. As the piston approaches the back end of the stroke, the head 22, leaving
the guide 23, engages with the helical tubular piece 24, and forcing it outward is by
its action turned through a small angle, and with it the boring bar 16. On the
return stroke the head 22 leaves the helical piece 24, which is held back by a
frictional appliance 28, Figure 9, and engaging with the guide 23 is prevented
thereby from turning whilst delivering its stroke. The helical piece 24 in turning
acts by means of teeth 29 formed on it on a toothed boss 30 on the valve rod 31.
The valve 32 is an oscillating one working in a cylindrical chamber 33 parallel to
the main cylinder 18, and owing to the play between the helical piece or quick

page_text: screw 24 and the parts 22, 27, on the piston rod, the valve 32 is moved only at or
near the ends of the strokes. The parts acting on the valve also act on the feed
screw 21 through a lever 34, connected by a link 35 to a tubular boss 36, this
last by a lever and pawl 37 acting on a ratchet wheel formed on an internally
screwed tube 38, through which the screw 21 passes. The feeding action is made
adjustable so that the extent for each stroke of the piston can be varied to suit
different cases. When a boring is to be put down to a great depth the lengths
are jointed to each other in the manner shown in Figure 12, Sheet 3, each joint
being fitted with a steel spring 39, which tends to keep the connection rigid when
opened out. The rod lengths jointed together in this way can be wound upon a
large polygonal drum or frame when they have to be drawn up out of the bore.
The piston rod 15 and cylinder 18 may be made large enough for the joints of the
boring rod to pass through, or the rod may be held outside of the cylinder
when the cylinder cannot be got quite in line with the position in which the
boring is to be made. Or two boring bars 16 may be worked by one cylinder 18,
as shown in Figures 13 and 14, Sheet 3, the piston rod being in that case
arranged to actuate a rocking shaft, 40, fitted with levers 41 at each side of
the frame, bracket, or standard 42, to which the cylinder is fixed and which
carries the rocking shaft, and also a second rocking shaft 43 having levers
on it to serve as guides to the upper or outer parts of the boring bars 16.
When the boring tool is to be worked by rotation without percussion the
power is transmitted, as shown in Figures 15 and 16, Sheet 3, by a wire or other
rope 44 to a pulley 45 mounted in a frame 46, which is fixed to or held against the
rock. The boring rod or spindle 16 passes through the boss of the pulley 45, and
is fed forward by means of a parallel screw spindle 21, which moves a block
engaging between collars or nuts on the spindle 16. The pulleys for the wire or
other driving rope are made as shown in Figures 17 and 18, that is, each with a
shallow grooved wooden trend or rim 47 connected to the boss or centre 48 by
light wrought-iron spokes 49, which are in pairs set wider apart at the boss than
at the rim, and which are fixed to the boss by rings 50 shrunk over segmental
parts formed on their inner ends.
'
Pulleys constructed as last described are suitable for wire or other ropes of various
sizes up
to the largest employed for mining purposes, and the spokes may be
formed with horns 51 projecting beyond the rim to keep the rope in its place.
In quarrying the boring apparatus has frequently to be applied upon the vertical
face of a rock, in which case whilst the apparatus may be conveniently suspended
from the overhanging arm of a derrick fixed at the top of the rock, it is desirable
to have a firm hold of the rock face to withstand the resistance to the boring action.
For this purpose holes are first bored a short distance into the rock, as shown in
Figure 19, Sheet 4, and each is tapped to receive a screwed bar 52 or a bar 53, to
which a cast-iron or other screw 54 is fixed. One or more horizontal bars are then
fixed on the screw held bars so as to be parallel to the rock face, and the supporting
and guiding frame of the boring cylinder is clamped upon the parallel bar or bars.
The bars might also be fixed to the rock in either of the ways shown at 55 or 56,
in Figure 19.
Bore holes inade for blasting rock are advantageously enlarged or undercut at
some distance in from the mouths of the holes. For effecting this enlargement a
rotating boring bar is used, and is fitted with one or two cutters jointed within a
recess near the point, and arranged so as to be turned outwards by means of
a wedge or of a worm moved by means of a rod passing along the bar, which is
made tubular for the purpose. Figures 20 and 21 are sections as at right angles to
each other of a modification in which two cutters jointed within a recess at the end
of the boring bar are formed with bevil toothed segments, which are in gear with a
bevil pinion on a central rod 57. In the modification shown in Figure 22 a single
cutter is moved by a worm on an internal rod 57, and in the modification shown in
Figure 23 the internal rod 57 acts on the cutter by means of a wedge formed on
its end. Figure 24 on Sheet 4 is a plan, and Figure 25 is a vertical section of one

page_text: modification of my improved machine for cutting coal or similar minerals. In this
machine a rotating boring bar 58 is held with several bearings by a jib 59, which
projects out laterally from a truck, or as is preferred from a slide frame.60 fitted
with screw feed gear 61 on a long guide fraune 62. The bar 58 is armed with
cutters at all possible points between the bearings, and a slow reciprocating motion
is imparted to the jib 59 so that the cutters may at one time work at parts opposite
to which the bearings have been at another time. The boring bar cuts with its
side and is fed along the guide frame in a direction at right angles to itself, and it
is driven from the crank shaft 63 of a small two-cylinder engine worked by
compressed air, or from a pulley driven by a rope transmitting motive-power from
a distance. A pinion on the crank shaft 03 gears with a spur wheel 64 fast on a
shaft having on it a pinion, which through an intermediate wheel drives a long
pinion on the boring bar 58. The engine and working details are on a casting 65
fitted into the sliding frame 60, so that it can be turned by means of a worm and
worn wheel, and the jib 59 is formed with its inner end at a higher level than its
outer part and fitted to slide in guides in the casting 65. The jib is made to
reciprocate by a lever on a vertical rocking shaft 66 worked by an eccentric on the
crank shaft 63.
Another modification of my improved coal cutting apparatus is shown in plan in
Figure 26, Sheet 5, and partially in sectional side elevation in Figure 27. In this
arrangement for rotating, boring or cutting bars 67 are mounted upon a jib 68,
which is fixed to the slide frame 60 or truck whilst working, although it can be
turned when required into any desired position, being formed in one piece with a
circular frame 65, which is adjustable, in the slide frame 60, by a worm and worm
wheel and which carries the engine details. Each bar 67 is arined with cutters
near its outer end, and the bars project to different distances so, that the least
projecting one of any adjacent two cuts in advance of the other in the direction in
which the slide frame 60 or truck moves. The bars 67 have bearings at their
cutting parts, such bearings being on blocks 69 fitted to slide on guides formed for
them on the jib 68; and the bars 67 are driven by means of pinions on them, two of
them in one direction by one spur wheel 70, and the other two in the opposite
direction by a second spur wheel 71 gearing with the first. Reciprocating motions
are imparted to all the bars 67 by means of oblique sides on the driving spur wheels
70, 71, acting between flanges on the pinions. With the described arrangements
the motions of one pair of bars 67 are balanced by the opposite motions of the other
pair, and the machinery can consequently be driven at a high speed with little vibra-
tion or concussion.
The winding, hauling, or power-transmitting ropes used in quarrying and mining
operations are by my Invention made to be more durable and flexible than the steel
ropes commonly used. The plaiting or hard twisting together of the wires or strands
in ordinary steel ropes causes them to injure and cut each other and leads to rapid
wear, which is avoided in my improved rope by laying the main wires close together
with a long or very slight twist. In one modification shown in Figure 28, Sheet 3,
a core 72 of hemp or other suitable compressible material has laid on it a sheath 73
of closely placed wires twisted very slightly in one direction, and outside of this a
second sheath 74 of wires slightly twisted in the opposite direction is put. There
may be more than two sheaths or layers of strong wire, but outside of all there is by
preference put a skin 75 of fine flexible wire plaited together.
Having thus particularly described ny said Invention and the manner of perform-
ing the same, I have to state that I do not restrict myself to the precise details
herein described or delineated but that what I believe to be novel and original and
claim as the Invention secured to me by the herein-before in part recited Letters
Patent is
1. The arranging or combining together of motive-power and air-compressing
apparatus, substantially in the improved manner hercin-before described with
reference to Figures 1 to 6, of the accompanying Drawings.

page_text: 2. The combination of parts constituting the improved rock-boring apparatus
herein-before described with reference to Figures 7 to 11 of the accompanying
Drawings.
3. The jointing together of boring rod lengths, substantially in the manner
herein-before described with reference to Figure 12 of the accompanying Drawings,
and the winding of them upon a polygonal drum or frame, as herein-before
described.
4. The working of two reciprocating boring bars by means of one cylinder com-
bined with rocking shafts and levers, substantially as herein-before described with
reference to Figures 13 and 14 of the accompanying Drawings.
5. The working of a rotating boring bar when operating upon rock by apparatus
driven by a wire or other rope, and substantially such as herein-before described
with reference to Figures 15 and 16 of the accompanying Drawings.
6. The constructing of pulleys for wire or other ropes, substantially in the improved
manner herein-before described with reference to Figures 17 and 18 of the accompany-
ing Drawings.
7. The fixing of bars to a rock face for the purpose of supporting boring apparatus
by any of the appliances herein-before described with reference to Figure 19 of the
accompanying Drawings.
8. The enlarging or undercutting of bore holes for blasting rock by means of bor-
ing bars with cutters fitted so as to be expanded by an internal rod as herein-before
described with reference to Figures 20 to 23 of the accompanying Drawings.
9. The combinations of parts constituting the coal cutting machines herein-before
described with reference to Figures 24 to 27 of the accompanying Drawings.
10. The application in coal-cutting machinery of one or more revolving spindles
carried in several bearings on a jib, the same being armed with cutters between the
bearings and being made to reciprocate and operating substantially as herein-before
described.
11. The making of wire or compound ropes for winding, hauling, or power-trans-
mitting purposes in the improved manner herein-beforo described with reference to
Figure 28 of the accompanying Drawings.
In witness, whereof, I, the said Graham Stevenson, have hereunto set my hand
and seal, this Sixteenth day of September, in the year of our Lord, One
thousand eight hundred and seventy-six.
זגCRITICA
GRAHAM STEVENSON.
ON. (L..
(L.S.)