IMPROVEMENTS IN MACHINERY FOR DRILLING ROCK AND SUBSTANCES
Year: 1878

page_text: LETTERS PATENT to Martin Macdermott, of Scott's Chambers, Pudding Lane,
in the City of London, Architect, and George William Elliott, of Altrincham,
in the County of Chester, Mining and Mechanical Engineer, for the Invention
of "IMPROVEMENTS IN MACHINERY FOR DRILLING ROCK AND
SUBSTANCES."
OTHER
Sealed the 25th October 1878, and dated the 28th June 1878.
PROVISIONAL SPECIFICATION left by the said Martin Macdermott and
George William Elliott at the Office of the Commissioners of Patents on the
28th June 1878.
MARTIN MACDERMOTT, of Scott's Chambers, Pudding Lane, in the City of London,
Architect, and GEORGE WILLIAM ELLIOTT, of Altrincham, in the County of Chester,
Mining and Mechanical Engineer. "IMPROVEMENTS IN MACHINERY FOR DRILLING
ROCK AND OTHER SUBSTANCES."
This Invention has for its object improvements in machinery for drilling rock
and other substances.
In order to give a succession of blows to rock by a drill bar which has a recipro-
cating to-and-fro motion given to it, and also a rotating or turning motion, so that
the drill may not strike the rock in the same place at each blow, and in order also
to gradually feed forward the drill bar as the rock is penetrated, we arrange drilling
machinery in the following manner: -
The drill bar may be continuous, and formed with a cutting edge at one end; or it may
be formed at this end with a socket to receive a drill cutter, and along its rear end it
has a screw thread cut upon it. The bar passes freely through a tube, at the rear end of
which is a nut that screws on to the screw thread on the bar. The tube is capable of
sliding to and fro in a tubular bearing. Around this bearing, and around the tube
which projects forward from it is a coiled spring; this spring bears at one end
against a collar on the tubular bearing, and at the other end against a collar at the
front end of the tube. Near the rear end of the tube is another collar, against

page_text: which a cam or cams on a revolving shaft are caused to bear; these cams, as they
revolve, pross back the tube, and then, when the cams get clear of the collar, the
tube, together with the drill bar which it carries, is thrown forward with great
velocity by the spring, and the drill is so caused to strike the rock.
At the rear end of the tube thero is a ratchet wheel, through the centre of which
the drill bar can slide endwise, and there is a feather on the ratchet wheel projecting
into a groove formed along the drill bar capable of turning around the rear end of
the tube, and around the drill bar is an arm carrying a pawl or ratchet.
As the tube and drill bar reciprocate to and fro the end of the ratchet arm comes
at each backward and forward movement of the tube against an incline, the ratchet
wheel is thereby turned and carried round with it the drill bar, so causing the drill
at the next forward stroke to striko in a different place, and also as the drill bar
turns in the nut it moves forward through the tube, and so gives the necessary
forward feod to the drill.
In order to prevent the drill bar turning back during the backward movement of
the ratchet there is at the forward end of the tube a loose collar, through which the
drill bar can move endwise, but not turn, and this loose collar is gripped by a
friction pad carried at the forward end of the tube.
The incline can be set to any desired angle to vary the forward feed according to
the hardness of the rock that is being drilled. Should the incline be set to feed
forward the drill more rapidly than the rock is penetrated the length of stroke of
the drill bar is thereby lessened, and consequently the length of incline along which
the end of the ratchet lever travels, thereby reducing the distance through which
the ratchet rotates, and diminishing the amount of forward feed. The arrangement
is therefore partly self-adjusting and automatic.
The incline and the tubular bearing before mentioned are both carried by a
frame, which also carries bearings for the axis of the cams. The bearings are
cylindrical on their exterior and serve as trunnions, by which the machine is attached
to a frame or legs; thus the machine can be set to drill at any required angle, and
it can be retained at the required anglo by clamps gripping the trunnions. The cam
axis, which is also the axis of the whole apparatus, may be revolved by a crank
handle or otherwise.
Instead of the incline levers might bo used, the ratchet also need not necessarily
move to and fro with the tube.
The nut which screws on to the drill stem may be in a nut box connected to tho
rear end of the tube in such a manner that it can readily be attached or detached
from it, or the nut may be formed in two parts, each capable of sliding outwards in
the nut box so as to move away from the screw. In order to be able readily to
thus disengage the nut from the screw we form one part of the nut with sido
pieces which pass one on either side of the screw, the other part of the nut slides
between these side pieces.
The ends of the side pieces are connected by a cross bar, through which a screw
is screwed; one end of this screw is coupled to the part of the nut which lies between
the side pieces, and at the other end is a head, by which the screw can be turned.
By turning the screw the two parts of the nut move away from one another, and
both halves are compelled to move away from the screwed drill stem by reason of a
pin on the nut box entering grooves in the two parts of the nut. When one part
ins moved to the extent required it is stopped by the pin, and cannot move further,
consequently the other part is compelled to move also, and so both parts must, of
necessity, free themselves from the screwed drill stem. By thus releasing the nut
from the screw on the drill bar, the drill bar, after it has bored a hole in rock, can
be drawn back without its being necessary to sorew it back all the way through
the nut.
The ratchet wheel on the screw stem of the drill we prefer to enclose in a tubular
casing which carries the pawl in a recess in its interior, and an arm projecting from
the circular casing serves as the ratchet lever arm to be acted on by the incline. This
ratchet apparatus may be used for turning the bars or stems of revolving drills.

page_text: The arrangement of split nut can also be used with revolving and other drill bars
of rock drills where the drill bars have a screw thread cut on their exterior.
When hollw revolving drill bars carrying diamonds or other gems at their
cutting extremity are used we form a screw thread on the exterior of the tubular
drill bar, and also a longitudinal groove, and to revolve the drill bar and give to it
a slow forward feed we mount upon the bar a bevil toothed wheel, which is free
to slide endwise upon the bar, but is prevented from turning upon it by a feather
entering the groove in the bar. Bearing against the front of this bevil wheel is a
long nut fitting the tube, and having the out side turned to work freely in a guide.
The outside of the bush on the back part of the bevil wheel is also turned to work freely
in a guide, these two guides being part of the body of the machine. Working in connec
tion with this bevil wheel is another bevil wheel having its axis at right angles to the
axis of the tube and other bevil wheel, and securely fastened on the end of a spindle
passing through a boss on the body of the machine, and having a small belt, pulley,
or pinion wheel secured to the other end of it, and which is caused to revolve by
the prime mover, thereby rotating the bevil wheels and tube.
Screwed into a boss on the guide, in which the long nut works, and bearing
against a piece of leather which bears against the nut, is a thumb screw, by means
of which any desired amount of friction may be put on the nut to prevent it
revolving with the tube, and in proportion as the nut is prevented from revolving
the tube will be caused to advance through it and bear against the rock; but when
the pressure against the rock causes the nut to bear against the revolving bevil
wheel, so that the friction between the nut and bevil wheel and the nut and tube is
sufficient to overcome the friction, retarding the revolution of the nut, then the nut
will revolve also, and cease to cause the tube to advance until the cutters have
penetrated the rock, and so reduced the pressure against them until it is too small
to cause the nut to revolve, and the tube is again made to advance.
By this arrangement the pressure of the cutters against the rock may be
regulated to any desired extent by the friction put upon the nut, and that pressure
kept constant through variable degrees of hardness of rock.
The two guides in which the nut and the bush at the back part of the bevil
wheel revolve are connected by a hollow cone to the boss, in which revolves the
spindle carrying the other bevil wheel and belt pulley.
The outside of the cone fits into a clip, by which it is attached to the standard or
fraine of the machine. The clip being slack the boss and cone are free to revolve
in it round the axis of the spindle to any desired angle, and there secured by
tightening the clip, thus allowing the tube and cutters to be set to any angle
without altering the position of the pulley or pinion, the centre of motion being
round the axis of the spindle.
At the opposite end to the cutting end of the tube there is an india-rubber pipe
attached by a suitable coupling, so as to allow a supply of water to be forced up
the tube to the cutters and allow the tube to revolve without the coupling and pipe
revolving also.
By attaching a cord or chain to this coupling, and passing it over a small pulley
attached to the body of the machine and hanging on the cord a weight, according
to the desired pressure, the tube and cutters are caused to bear against the rock
with a constant pressure, thus making another form of feed arrangement. "In this
case the tube is not screwed and the nut not required, neither the boss on the back
of the bevil wheel, but the plain tube bears direct in the guides.
•
Instead of hanging a weight to the cord the end of the cord is secured to a small
drum, round which it is wound, and a friction arrangement on the main shaft or
driving wheel is caused to bear against the drum and bring a fixed strain on the
cord to pull the tube against the rock.
The necessary pressure of water is supplied by having a water-tight bag filled
with water, to which is attached the india-rubber pipe, and sufficient weight put
upon the bag to give the necessary pressure.
The driving pulley or wheel is attached to the standard of the machine by a
clamp and has a handle secured to the rim, by which it is turned.

page_text: In open quarry and mining work, where there are no facilities for fixing a
standard, we use a tripod stand formed of one main tube, to which the machine is
clamped, and two smaller tubes, forming the back legs or struts. The tubes have
points at the bottom ends and are attached at the top, so as to admit of being
opened out at the bottom independently of each other and a removable heavy
weight clamped on the bottom of each.
Another form of stand is made by having an upright tube, to which the machine
and gearing is clamped, and at the bottom attached by an universal joint to the
middle of a shorter tube at right angles to it, and to which is firmly fixed a
triangular platform on three short legs, so as to stand firmly on the ground.
Weights may be put upon this platform, or the workman may stand upon it, and
thus hold it sufficiently rigid to hold the machine, the thrust upon the rock being
very slight. Instead of having short legs to the triangular platform they may be
long ones, so as to raise it high enough to form a stool, whereon the workman may
sit, and thus hold it firm enough while the machine is being worked. These last three
arrangements are intended to be very light and portable, and to be used for drilling
small holes in very hard rock. Where larger holes are required and there is room
enough to work it the following stand is preferred:-A frame is made to form a
seat, upon which the workınan sits, the legs of the frame resting upon the ground
on three points. On each side of the frame is a boss forming the bearings for the
axis of the driving wheel, which is worked by a treadle on each side. On the
outside of each boss is fitted a radial arm, passing along each side of the wheel to
the outside of its circumference, and there joined together by a boss, to which the
body part of the drill is attached in such a manner as to allow the tube to turn
round to any angle at right angles to the axis of the driving wheel and there be
secured.
The radial arms are free to move round the bosses on the framework, and
consequently round the axis of the driving wheel, and are secured in any desired
position by a bolt passing through each arm, and sliding in a slot in a segment
attached to the frame.
By this arrangement a hole may be drilled at right angles to the axis of the
driving wheel in any direction within a semicircle, and without interfering with
the driving belt or gearing, whichever may be used, the weight of the man keeping
the machine sufficiently rigid, and by working the machine by treadling have his
hands free to attend to any part requiring his attention.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Martin Macdermott and George William Elliott in the Great Seal
Patent Office on the 28th December 1878.
MARTIN MACDERMOTT, of Scott's Chambers, Pudding Lane, in the City of London,
Architect, and GEORGE WILLIAM ELLIOTT, of Altrincham, in the County of Chester,
Mining and Mechanical Engineor. "IMPROVEMENTS IN MACHINERY FOR DRILLING
ROCK AND OTHER SUBSTANCES."
This Invention has for its object improvements in machinery for drilling rock and
other substances.
In order to give a succession of blows to rock by a drill bar which has a recipro-
cating to-and-fro motion given to it, and also a rotating or turning motion, so that
the drill may not strike the rock in the same place at each blow, and in order also
to gradually feed forward the drill bar as the rock is penetrated, we arrange drilling
machinery in the following manner :-
The
The drill bar may be continuous and forward, with a cutting edge at one end, or
it may be formed at this end with a socket to receive a drill cutter, and along its
rear end it has a screw thread cut upon it. The bar passes freely through a tube at
the rear end of which is a nut that screws on to the screw thread on the bar.
tube is capable of sliding to and fro in a tubular bearing. Around this bearing and
around the tube which projects forward from it is a coiled spring; this spring bears
at one end against a collar on the tubular bearing, and at the other end against a
collar at the front end of the tube. Near the rear end of the tube is another collar,
against which a cam or cams on a revolving shaft are caused to bear; these cams
as they revolve, press back the tube, and then when the canis get clear of the collar
the tube, together with the drill bar which it carries, is thrown forward with great
velocity by the spring, and the drill is so caused to strike the rock.
At the rear end of the tube there is a ratchet wheel through the centro of which
the drill bar can slide end wise, and there is a feather on the ratchet wheel projecting
into a groove formed along the drill bar. Capable of turning around the rear
end of the tube and around the drill bar is an arm or arms carrying a pawl or
ratchet.
As the tube and drill bar reciprocate to and fro the end of the ratchet arm comes
at each backward and forward movement of the tube against an incline, or is other-
wise caused to turn, the ratchet wheel is thereby turned, and carries round with it
the drill bar so causing the drill at the next forward stroke to strike in a different
place, and also as the drill bar turns in the nut it moves forward through the tube,
and so gives the necessary forward feed to the drill.
In order to prevent the drill bar turning back during the backward movement of
the ratchet, there may be at the forward end of the tube a loose collar through
which the drill bar can move endwise, but not turn, and this loose collar may be
gripped by a friction pad carried at the forward end of the tube, or other means
may be employed for impeding the drill bar from turning back.
The incline can be set to any desired angle to vary the forward feed according to
the hardness of rock that is being drilled. Should the incline be set to feed forward
the drill more rapidly than the rock is penetrated, the length of stroke of the drill
bar is thereby lessened, and consequently the length of incline along which the end
of the ratchet lever travels, thereby reducing the distance through. which the ratchet
rotates, and diminishing the amount of forward feed. The arrangement is therefore
partly self-adjusting and automatic.
The incline and the tubular bearing before mentioned are both carried by a frame
which also carries bearings for the axis of the cams. The bearings are cylindrical on
their exterior, and serve as trunnions by which the machine is attached to a frame
or legs, thus the machine can be set to drill at any required angle, and it can be

page_text: retained at the required angle by clamps gripping the trunnions. The cam axis,
which is also the axis of the whole apparatus, may be revolved by a crank handle
or otherwise.
Instead of the incline levers might be used, the ratchet also need not necessarily
move to and fro with the tube.
The nut which screws on to the drill stem may be in a nut box connected to the
rear end of the tube in such a manner that it can readily be attached or detached
from it, or the nut may be formed in two parts, each capable of sliding outwards in
the nut box, so as to move away from the screw. In order to be able readily to
thus disengage the nut from the screw we form one part of the nut with side pieces
which pass one on either side of the screw; the other part of the nut slides between
these side pieces.
The ends of the side pieces are connected by a cross bar through which a screw
is screwed, one end of the screw is coupled to the part of the nut which lies between
the side pieces, and at the other end is a head by which the screw can be turned.
By turning the screw the two parts of the nut move away from one another, and
both halves are compelled to move away from the screwed drill stem by reason
of a pin on the nut box entering grooves in the two parts of the nut. When
one part has moved to the extent required it is stopped by the pin and cannot
move further, consequently the other part is compelled to move also, and so both
parts must of necessity free themselves from the screwed drill stem. By thus
releasing the nut from the screw on the drill bar, the drill bar, after it has bored
a hole in rock, can be drawn back without its being necessary to screw it back all
the way through the nut.
The ratchet wheel on the screw stem of the drill we prefer to enclose in a tubular
casing which carries the pawl in a recess in its interior, and an arm projecting from
the circular casing serves as the ratchet level arm to be acted on by the incline.
This ratchet apparatus may be used for turning the bars or stems of revolving
drills.
The arrangement of split nut can also be used with revolving and other drill bars
of rock drills where the drill bars have a screw thread cut on their exterior.
When hollow revolving drill bars carrying diamonds or other gems at their
cutting extremity are used, we form a screw thread on the exterior of the tubular
drill bar, and also a longitudinal groove; and to revolve the drill bar and give to it
a slow forward feed we mount upon the bar a bevil-toothed wheel, which is free to
slide endwise upon the bar, but is prevented from turning upon it by a feather
entering the groove in the bar. Bearing against the front of this bevil wheel is a
long nut fitting the tube and having the outside turned to work freely in a guide.
The outside of the bush on the back part of the bevel wheel is also turned to work
freely in a guide, these two guides being part of the body of the machine. Working
in connection with this bevel wheel is another bevel wheel having its axes at right
angles to the axis of the tube and other bevel wheel, and securely fastened on the
end of a spindle passing through a boss on the body of the machine, and having a
small belt, pulley, or pinion wheel secured to the other end of it, and which is
caused to revolve by the prime mover, thereby rotating the bevel wheels and tube.
Screwed into a boss on the guide in which the long nut works, and bearing
against a piece of leather which bears against the nut, is a thumbscrew, by means
of which any desired amount of friction may be put on the nut to prevent it
revolving with the tube; and in proportion as the nut is prevented from revolving
the tube will be caused to advance through it and bear against the rock; but when
the pressure against the rock causes the nut to bear against the revolving bevel
wheel, so that the friction between the nut and bevel wheel and the nut and tube
is sufficient to overcome the friction retarding the revolution of the nut, then the
nut will revolve also and cease to cause the tube to advance until the cutters have
penetrated the rock, and so reduced the pressure against them until it is too small
.to cause the nut to revolve and the tube is again made to advance.

page_text: By this arrangement the pressure of the cutters against the rock may be regulated
to any desired extent by the friction put upon the nut, and that pressure kept
constant through variable degrees of hardness of rock.
The two guides in which the nut and the bush at the back part of the bevel
wheel revolve are connected by a hollow cone to the boss in which revolves the
spindle carrying the other bevel wheel and belt pulley.
The outside of the cone fits into a clip by which it is attached to the standard or
frame of the machine. The clip being slack, the boss and cone are free to revolve
in it round the axis of the spindle to any desired angle, and there secured by
tightening the clip, thus allowing the tube and cutters to be set to any angle
without altering the position of the pulley or pinion, the centre of motion being
round the axis of the spindle.
At the opposite end to the cutting end of the tube there is an india-rubber pipe
attached by a suitable coupling, so as to allow a supply of water to be forced up
the tube to the cutters and allow the tube to revolve without the coupling and pipe
revolving also.
By attaching a cord or chain to this coupling and passing it over a small pulley
attached to the body of the machine, and hanging on the cord a weight according
to the desired pressure, the tube and cutters are caused to bear against the rock
with a constant pressure, thus inaking another form of feed arrangement. In this
case the tube is not screwed and the nut not required, neither the boss on the back
of the bevel wheel, but the plain tube bears direct in the guides.
Instead of hanging a weight to the cord, the end of the cord is secured to a small
drun round which it is wound, and a friction arrangement on the main shaft or
driving wheel is caused to bear against the drum and bring a fixed strain on the
cord to pull the tube against the rock.
The necessary pressure of water is supplied by having a water-tight bag filled
with water, to which is attached the india-rubber pipe and sufficient weight put
upon the bag to give the necessary pressure.
The driving pulley or wheel is attached to the standard of the machino by a
clamp, and has a handle secured to the rim by which it is turned.
In open quarry and mining work where there are no facilities for fixing a
standard we use a tripod stand formed of one main tube, to which the machine is
clamped, and two smaller tubes forming the back legs or struts. The tubes have
points at the bottom ends, and are attached at the top so as to admit of being
opened out at the bottom independently of each other, and a removeable heavy
weight clamped on the bottom of each.
Another form of stand is made by having an upright tube to which the machine
and gearing is clamped, and at the bottom attached by an universal joint to the
middle of a shorter tube at right angles to it, and to which is firmly fixed a
triangular platform on three short legs, so as to stand firmly on the ground; weights
may be put upon this platform, or the workman may stand upon it, and thus hold
it sufficiently rigid to hold the machine, the thrust upon the rock being very slight.
Instead of having short legs to the triangular platform they may be long ones, so as
to raise it high enough to form a stool whereon the workman may sit, and thus
hold it firm enough while the machine is being worked. These last three arrange-
ments are intended to be very light and portable, and to be used for drilling small
holes in very hard rock. Where larger holes are required and there is room enough
to work it the following stand is preferred:-A frame is made to form a seat upon
which the workman sits, the legs of the frame resting upon the ground on three
points. On each side of the frame is a boss forming the bearings for the axis of the
driving wheel, which is worked by a treadle on each side. On the outside of each
boss is fitted a radial arm passing along each side of the wheel to the outside of its
circumference, and there joined together by a boss to which the body part of the
drill is attached in such a manner as to allow the tube to turn round to any angle
at right angles to the axis of the driving wheel and there be secured.
The radial arms are free to move round the bosses on the framework, and

page_text: consequently round the axis of the driving wheel, and are secured in any desired
position by a bolt passing through each arm, and sliding in a slot in a segment
attached to the frame.
By this arrangement a hole may be drilled at right angles to the axis of the
driving wheel in any direction within a semicircle, and without interfering with
the driving belt or gearing, whichever may be used, the weight of the man keeping
the machine sufficiently rigid, and by working the machine by treadling, have his
hands free to attend to any part requiring his attention.
Figure 1 shews a front elevation; Figure 2, a sectional side elevation; and
Figure 3, a plan view of a percussive drilling apparatus constructed according to
our Invention.
A is the drill bar carrying a drill cutter at one end, and a weight at its opposite
end. The bar has a screw thread cut upon it as shown. The bar also passes freely
through a tube B which carries a nut C; the screw thread on the bar screws
through this nut. The tube is free to slide to and fro through a tubular bearing D
forming part of a frame D'; from the opposite sides of this frame project trunnions,
which can be gripped and held by the fixed side standards E of the machine. The
frame, together with the tube and drill bar, can thus be set at any required angle, and
can then be locked at this angle by screwing up the bolts E, so causing the plates of
which the side standards are formed to grip and lock the trunnions; F is a coiled
spring around the tubular bearing D, and the end of the tube B which projects
from it. The spring at its ends bears against collars on the tubular bearing and
tube respectively.
On to the rear end of the tube B is screwed a collar B' of a rectangular form,
forming part of what we call the nut box; it slidos between guides on the frame D',
and is so prevented from turning; G, G, are cams which act against this collar;
they are carried by an axis H, which passes through the trunnions of the frame
1, and has fixed to it at its ends fly wheels carrying crank handles by which it can
bo revolved.
As before explained, the cams as they are carried round serve to press back the
collar B' and tube B, and when the cams get clear of the collar, the coiled spring F
throws the tube forwards. At the roar end of the nut box I is a short tube K,
through which the drill bar can slide endwise. The tube K is held up to the end
of the nut box by a loose split collar J, as shewn; there is also another similar
collar free to turn around its opposite end. At K' the tube has ratchet teeth
formed around it. Each of the loose collars J, J, has a short arm projecting from
it ; each arm carries a spring pawl, and the pawls engage with the the ratchet teeth
on opposite sides of the tube K, as seen at Figures 4 and 5, which shew these
parts separately. Each arm has also jointed to it a link L; the opposite ends of the
links are free to turn on universal joints at L'. It will thus be seen that as the
tube rises the collars I, 1', will be caused to turn in opposite directions, and the
pawl carried by one collar will be turning the tube K, whilst the pawl carried
by the other collar is slipping over the ratchet teeth upon it. As the tube is thrown
forward the effect is reversed, and the pawl which before was out of action now
comes into action and again turns the tube; thus the tube is caused to turn
continuously in one direction and turns the drill bar with it, as a feather carried by
the tube enters a longitudinal groove in the bar. The distance it is caused to turn
for each forward and backward movement of the rod can be varied by varying the
position of the joints L¹, so as to alter the angle at which the links work; these as
shewn at Figure are carried by a slotted plate M, which can be raised or lowered
and secured in any desired position to the frame D' by bolts M¹.
The above-described arrangement for effecting the forward feed of the drill bar
has the advantage that the feed is increased towards the end of the forward stroke
of the drill and the commencement of the backward stroke, thus enabling the feed
to become more self-adjusting. Since if the feed is too quick for the hardness of
rock being drilled and the drill bar is screwed through the nut too rapidly, the
stroke of the drill bar will be lessened, thus reducing that part of the stroke of

page_text: the links which gives the greatest amount of feed to the drill bar, and so forming a
very sensitive and almost self-regulating feed. The same link arrangement can also
be used when a single ratchet pawl is used in place of two, as above described.
When however one pawl only is used, provision must be made either by a friction
clip or otherwise for preventing the drill bar turning back when the pawl is not in
action to turn it forwards.
As before stated, inclines may be used instead of links; in this case the arm or
arms which carry the pawls come against and are driven by the inclinos in the
manner before explained.
Figures 6 and 7 show, as an illustration of this arrangement, a single arm and
pawl, together with one of the inclines for acting on this arm.
The nut Cis, as shewn in the Drawings, made in two parts, which can be moved
away from one another, and away from the stem of the drill, merely by turning a
small thumb screw.
The nut box and nut are shewn separately at Figures 8, 9, and 10; the manner
in which these parts are formed is herein-before fully described, and is also clearly
shewn by these Drawings.
In place of using a screw to move the two parts of the nut towards or away from
one another, a cam or equivalent mechanism might be used.
By forming the nut in the manner described, it can readily be detached from the
screw stem, and the drill bar can be at any time quickly drawn back out of the
holo that has been bored by it, or can be set in proper position for commencing
work.
Divided nuts, coupled together as above described, may be applied to other forms
of drilling machinery, and the nut may vary in form, according to the nature of the
machine in which it is used.
Another form of nut box is shewn at Figures 11 and 12.
Figures 13 and 14 shew a side elevation and plan in section of a diamond drilling
machine constructed according to our Invention.
A is the hollow drill bar, carrying diamonds or other hard gems at its cutting
extremity, as is well understood; it is caused to revolve by a sinall bevil wheel B,
through which the stem is free to slide, but by a groove and feather is prevented
from turning within it. The bevil wheel B can be driven by another bevil wheel C
on a shaft D, as shewn. The drill stem may be constantly pressed forward by a
weighted cord, as shewn, or in the manner herein-before described. The bearing of
the shaft D is coupled by a clamp E to an arm F, which may form part of any
suitable frame.
Figures 15 and 16 shew one of the diamond drills carried by a standard G, which
can be contracted in length or elongated, and so fixed between the floor and roof of
a mine in the manner well understood.
Figures 17, 18, and 19 shew a side elevation, end elevation, and plan of a
diamond drill, carried by a frame whereon the operator sits and works the drills by
treadles.
Figures 20 and 21 shew a side elevation and plan of another form of stand for
the diamond drill, arranged in the form of a chair with three legs, and whereon the
operator sits and works the drill by hand, as in the machine shewn at Figures 15
and 16.
The tubular upright is secured to the seat by a universal joint, and the drill can
be turned in any direction.
Having thus described the nature of the Invention and the manner of performing
the same, we would have it understood that we claim,—
'
First. The combined arrangement of drilling machinery, substantially as herein-
before described and illustrated at Figures 1, 2, and 3.
Second. The combined feeding forward and turning of the drill, by having the
drill bar screwed and working through a nut, and caused to turn a little at each
stroke by means of a ratchet actuated by any suitable mechanism.
Third. The combined feeding forward and turning of the drill, by having the drill

page_text: bar screwed and working through a nut, and caused to turn a little at each stroke
by means of a ratchet or ratchets actuated by a link or links, or an inclined plane
or planes, substantially as shown and described.
bar
Fourth. Arranging the nut through which the drill bar passes, so that the drill
may be withdrawn without unscrewing it all the way through the nut, either by
the split nut arrangement shewn, or making the nut readily detachable from the
tubular bearing or otherwise.
Fifth. So forming the two parts of the split nut that one part may slide inside
the other, and each part, together with a stop in the nut box, may form a fulcrum
by which the other part is separated from and brought in contact with the screw.
Sixth. Attaching the body of the machine to the frame or legs, so that it can
be turned round the axis of the driving shaft to any angle without moving the
frame or legs, and there held by the trunnions on the body of the machine. Also
arranging the guide bush on the body of the machine, so that a portion of it may be
inside the mainspring.
Seventh. The arrangement of feed for a rotative drilling machine, by having the
drill bar or tube screwed and passing through a nut, and retarding the revolution
of the nut by adjustable friction, thereby causing the drill bar or tube to pass
through it and bear against the material to be drilled, and arranging the nut to bear
against the driving pulley or wheel, so that when the pressure becomes excessive, it
may cause the nut to revolve, and thereby cease to force forward the drill.
Eighth. Attaching the body of the machine to the frame or stand, so that the drill
may be turned round to any angle at right angles to and round the axis of the
driving pulley or wheel.
Ninth. The arrangements of stool and treadle stands, substantially as herein-
before described and shown.
Tenth. The general arrangement and combination of parts of rotative drilling
machines, substantially as herein-before described and shown.
In witness whereof, I, the said Martin Macdermott, have hereunto set my hand
and seal, this Twenty-fourth day of December, in the year of our Lord One
thousand eight hundred and seventy-eight.
M MACDERMOTT
(1.0)