IMPROVEMENTS IN APPARATUS FOR DRILLING HOLES IN ROCKS AND OTHER HARD SUBSTANCES."
Year: 1873

page_text: LETTERS PATENT to Edmund Edwards, of 38, Southampton Buildings,
Chancery Lane, in the County of Middlesex, Engineer and Patent
Agent, for the Invention of IMPROVEMENTS IN APPARATUS FOR DRILLING
HOLES IN ROCKS AND OTHER HARD SUBSTANCES."

page_text: 26
the substance operated on as the depth of the hole being drilled
increases, and it relates more especially to that form of rock boring
apparatus for which I obtained Provisional Protection on my application
for Letters Patent for Improvements in the Construction of Engines
driven by Steam, Compressed Air, or other Elastic Fluid, or by Water
especially applicable to Rock Boring Engines," dated February 13th, 1878,
and numbered 541, but is also applicable to other rock boring engines.
In the Provisional Specification filed by me with my application for
Letters Patent above referred to, I described a screw working in a nut
or its equivalent, and by its partial rotation after each stroke of the
drill, causing the cylinder to advance forward upon the frame which
carries it.
My improved method of actuating such screw consists in forming
upon or attached to the cover of the outer one of the principal cylinder
of the apparatus a smaller cylinder at right angles to the latter, and
containing a piston. One end of this small cylinder communicates
directly by a passage formed in the cylinder cover with the outer end
of the large cylinder, and its other end communicates by a passage
formed in the cylinder cover, and upon or attached to the side of the
large cylinder with the inner end of the latter. By this arrangement,
as the steam or other fluid which drives the apparatus is admitted
alternately to each end of the large cylinder, the piston in the small
cylinder is simultaneously driven backwards and forwards.
Upon the outer end of the feeding screw already referred to, I form
a ratchet wheel having suitable teeth upon its face or circumference,
and I form a slot in the side of the small cylinder, through which an
arm carrying a pall or ratchet projects, one end of which arm turns
loosely upon the screw shaft, and the other end enters an annular groove
formed round the moveable piston. The ratchet or pall actuates the
teeth of the ratchet wheel when it is thus caused to reciprocate in the
method described, and the principal cylinder is thus fed forward as
required. An arm fixed to the piston may project through the slot, and
may carry a pall operating directly upon the teeth of the ratchet wheel
instead of the arrangement described; and friction plates or brakes,
which may be connected to the arm or pall, or adjusted by springs or
screws may be used to prevent the ratchet wheel from being moved too
far by the pill, or from recoiling after each impulse by the latter. The

page_text: small cylinder, instead of being fixed to or forming part of the cylinder
cover, may be removed to any convenient distance or position, the steam
or other fluid being brought to it through suitable pipes, and instead of
the piston in it being moved in one direction by the pressure of the
steam from the outer end of the cylinder, it may be moved in that
direction by a spring or weight, and only in the other direction by the
pressure of steam from the inner end of the cylinder (the latter being
the direction of its motion during which I prefer that it should aotuate
the ratchet wheel and screw).
By the arrangements described, greater simplicity of construction,
lightness, cheapness, and durability of parts are attained, than in such
apparatus as heretofore constructed.
Where rock of irregular harduess is being drilled it is important that
if the drill should take a stroke of too little penetration, the apparatus
should not then be advanced forward, but should retain its position until
sufficient penetration has been accomplished by successive strokes.
Where this regulation is required, I form a valve in the inner end of the
passage communicating with the inner end of the principal cylinder, and
I form a projection upon this valve, which enters the cylinder in such a
manner that it is struck by the piston of the cylinder, and the valve is
thereby lifted from its seat sufficiently to admit the steam (or other
fluid) to pass to the small cylinder and actuate its piston, and through
it the ratchet wheel and screw as already described.
If by reason of a blow of too little penetration of the drill the piston
in the principal cylinder does not advance sufficiently far to lift the
valve, the small piston remains motionless, and after that stroke the
apparatus is not advanced forward.
The accompanying Drawings are in illustration of my Invention.
Figure 1, Sheet I., is a longitudinal section of part of the apparatus
(shewn broken off); Figure 2 is an end view of the same.
Figure 3, Sheet II., is a sectional plan of the apparatus; and Figure 4
is a sectional plan upon a smaller scale, shewing a part of my improve-
ments applied to boring apparatus constructed according to my former
Provisional Specification already referred to.
a is the principal cylinder; b, one of the pistons working in it (both of
which are shewn in Figure 4), and c is the screw for feeding the cylinder

page_text: forward; d is the small cylinder attached to the cylinder cover e; and ✈
is the piston working in it, and having pieces of wood or other somewhat
elastic substance a, x, let into its ends to receive the force of any blow
against the ends of the cylinder d. The ratchet wheel 9 upon the
screw c is driven by the arm i and the pall k.
The outer end of the 5
arm i is shewn passing through a slot in the cylinder d, and entering the
annular groove / in the piston t, by which the arm is driven backward
and forward. m is a passage communicating with the outer end of the
principal cylinder through the cylinder cover e, and n is a passage com-
municating with its other or inner end, and having arranged in it the 1
valve o, a projection upon which is struck when necessary by the
piston b.
If the piston 6 does not travel sufficiently far to lift the
valve o, the steam is not admitted into the passage n, and the small
piston d consequently does not make a stroke.
P
A slight spring is shewn
for the purpose of keeping the valve o in its seat.
The dotted lines in Figure 4 shew another arrangement which I some-
times use for the same purpose, in which no valve is required. s is an
annular recess formed round the outer piston 61, and communicating by
the passage t formed in the piston rod with the steam space upon the
inner side of the piston b. The passage n, instead of being carried on to
the inner end of the cylinder and containing a valve (as shewn in the
Drawing) terminates in a port into the cylinder nearly opposite to the
annular recess s, shewn in dotted lines at v.
When the drill penetrates sufficiently for the piston 6¹ to bring the
recess & opposite the port v, the steam (or other fluid) has access to the
back of the small piston d, which accordingly makes its return stroke as
already described. If the piston 61 does not travel sufficiently far, the
port v remains closed, and the small piston remains unmoved. In this
arrangement I prefer to give the circular angular motion to the pistons
and drill by means of longitudinal helical grooves or recesses formed
upon the piston rod at the part w, and I make a catch or detent fitting
into a recess formed upon the cylinder with which the part w works, and
turning upon a centre parallel with the piston rod. The other end of
the catch or detent I connect to a small piston working in a short
cylinder at right angles to the piston rod, so that when the steam is
admitted to the end of the principal cylinder the small piston is forced
out and brings the catch or detent into contact with the helical grooves.
On the return stroke of the drill the catch or detent is removed from

page_text: the latter by a spring arranged above the small piston; or the catch or
detent may be formed upon the piston itself, and be put into operation
when the piston is forced down and released when the piston is forced
out, and it may operate upon a ring having notches at its circum-
ference, and having a tooth working in a longitudinal slot in the piston
rod; so that the latter may be turned when the ring is turned, though
the ring is allowed no longitudinal movement. This arragement may
be used in combination with the twisted bar already referred to, or in
such case a simple spring catch or detent fitting into the teeth upon the
ring described may be used.
In order to fix the drill to the piston rod or bar I make the latter
hollow for a sufficient depth, and near the outer end I cut a rectangular
slot partly or entirely through it. I fit a loop or clip into this slot,
through which the drill bar passes, and I tighten the loop by means of
a wedge driven between the loop and the piston bar, so that its
momentum has a tendency to tighten it at each stroke. The drill bar
may be made slightly smaller in diameter where the loop fits it,and
when necessary it may be drawn out and refixed, and a bar or stopping
piece may be temporarily placed below it in the piston bar.
SPECIFICATION filed in pursuance of the conditions of the Letters
Patent, and of an Order of the Lord Chancellor, by the said
Edmund Edwards in the Great Seal Patent Office on the 14th
October 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDMUND
EDWARDS, of 38, Southampton Buildings, Chancery Lane, in the County
of Middlesex, Engineer and Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventh day of April, in the year of our
Lord One thousand eight hundred and seventy-three, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Edmund Edwards, Her special licence that I,
the said Edmund Edwards, my executors, administrators, and assigns, or
such others as I, the said Edmund Edwards, my executors, administrators,
and assigns, should at any time agree with, and no others, from time to

page_text: time and at all times thereafter during the term therein expressed, should
and lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and
Isle of Man, an Invention for "IMPROVEMENTS IN APPARATUS FOR DRILLING
HOLES IN ROCKS AND OTHER HARD SUBSTANCES," upon the condition (amongst
others) that I, the said Edmund Edwards, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of
their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent
Office on or before the Fourteenth day of October One thousand eight
hundred and seventy-three.
NOW KNOW YE, that I, the said Edmund Edwards, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement and accompanying Drawings (that is to say): —
-
My Invention has for its objects improvements in the methods and
apparatus used for causing the drills in reciprocating rock boring engines,
as ordinarily constructed and used, to advance forward towards the
substance operated on as the depth of the hole which is being drilled i
increases; and it relates more especially to that form of rock boring
engine for which I obtained Royal Letters Patent, dated February 13th,
A.D. 1873, and numbered 541, but it is also applicable to other forms of
rock boring engines.
In the Specification filed by me as one of the conditions of the said
Letters Patent I have described a screw working in a nut or its equiva-
lent, and by its partial rotation after each stroke of the drill causing the
cylinder and piston or pistons which drive the drill to advance forward
upon the fixed frame which carries them.
The first part of my present Invention consists of an improved:
arrangement of apparatus for causing such screw to rotate. For this
purpose I form upon or attach to the cover of the outer end of the
principal cylinder of the engine a smaller cylinder at right angles to the
latter, and containing a piston which works freely but sufficiently steam-
tight within it.
One end of this small cylinder communicates directly
with the outer end of the cylinder by means of a passage formed in
the cylinder cover, and its other end communicates by means of a

page_text: passage, which passing through the cylinder cover is carried along or
attached to the side of the principal cylinder the other or inner end
of which it finally enters. By this arrangement as the steam or
other fluid which drives the apparatus is admitted alternately to each
end of the large cylinder the piston in the smaller cylinder is simul.
taneously driven backward and forward. An adjustable screw may be
fitted at one or both ends of the small cylinder to regulate the travel of
the piston. Upon the outer end of the feeding screw already referred
to, which causes the cylinder to advance forward, I form or fix a ratchet
wheel having suitable angular teeth formed upon its face or circum-
ference, and I make an opening or slot in the side of the small cylinder,
through which an arm carrying a pall or ratchet projects, one end of
the arm turning loosely upon the screw shaft, and the other end after
passing through the slot entering an annular groove formed round the
moveable piston. The ratchet or pall upon the moveable arm is arranged
so as to actuate the teeth of the ratchet wheel when moved in one
direction, and to pass over them when moved in the opposite direction.
As the small piston moves backward and forward in its cylinder as
already described it moves the arm with it, and the ratchet upon the
latter drives the wheel round to the extent of one tooth at each such
forward movement, and thus rotates the screw and advances the cylinder
and drill.
Instead of the arrangement described an arm fixed to the small piston
may project through the small slot and may carry a pall or catch
operating directly upon the teeth formed upon the circumference of the
wheel instead of through the intervention of a lever, and friction plates
or brakes which may be connected to the arm or pall and adjusted by
springs or screws may be used to prevent the ratchet wheel from being
moved too far by the pall, or from recoiling after each impulse of the
latter. Instead of a ratchet wheel and pall as described I sometimes
use a plain wheel and a friction tooth so arranged that in travelling in
one direction it passes freely over the edge of the wheel, but in travelling
in the other direction its friction grips the wheel and causes it to move
round. Sometimes I arrange the small cylinder so that a rod attached
to its piston passes through a stuffing box and carries at its outer end a
pall or ratchet which actuates the wheel as already described. The small
cylinder instead of being fixed to or forming part of the cylinder cover
may be removed to any convenient distance or position, the steam or

page_text: other driving fluid being brought to it through suitable pipes, and the
feeding screw being connected to the ratchet wheel by rods or other
suitable means. Instead of the piston in the small cylinder being moved
in one direction by the pressure of the steam admitted from the outer
end of the large cylinder it may be moved in that direction by a spring
or weight, and only in the other direction by the pressure of steam from
the inner end of the cylinder as above described (the latter being the
direction of its motion in which I prefer that it should actuate the
ratchet wheel and screw). By the arrangements described greater
simplicity of construction, lightness, cheapness, and durability of parts
are attained than in such apparatus as heretofore constructed.
It is sometimes important (especially if rock or other substance varying
in hardness is being drilled) that if the drill should make a stroke or cut
of too little penetration the cylinder and drill should not be advanced
forward after such stroke, but should retain its position until sufficient
penetration has been effected by a succession of strokes. Where such
regulation or retardation of the feed is required I fit a valve into a seat
formed or fitted in the inner end of the passage communicating from
the small cylinder to the inner end of the large cylinder, so that when
the valve is on its seat (upon which it is pressed by a spring) the steam
is prevented from passing into the passage. I form upon the valve a
projection which enters the cylinder in such a manner that it is struck
by the piston which drives the drill at the inner end of its stroke, and
the valve is thereby lifted from its seat sufficiently to admit the steam to
pass through the passage to the small cylinder, the piston in which it
actuates, and through it the ratchet wheel and feeding screw, as already
described. When by reason of a blow of too little penetration of the
drill the piston in the large cylinder does not advance sufficiently far to
lift the valve the small piston, together with the ratchet wheel and
feeding screw, remain motionless, and the cylinder and drill are not
advanced forward. Instead of a projection upon the valve the latter
may itself be of such a diameter that its edge projects into the cylinder
and is lifted by the piston, and sometimes I arrange the valve and seat
in a line at an angle to the bore of the cylinder, so that when the valve
is lifted sufficiently high the piston can pass it, and a space can thus be
left in the cylinder beyond the valve if required.
The accompanying Drawings are in illustration of my Invention.
Figure 1 Sheet I., is a longitudinal section of part of the cylinder

page_text: (shewn broken off) of a rock drilling engine having my improved
apparatus applied thereto; Figure 2 is an end view of the same, partly
in section.
Figure 3 is a sectional plan of part of the apparatus, shewing the valve
for regulating the amount of feed.
Figure is a sectional plan (upon a smaller scale) of part of a rock
drilling engine constructed according to the Specification of my Patent
dated February 13th, A.D. 1873, and numbered 511, already referred to,
and having my improved apparatus as above described applied to it.
The same letters of reference refer to corresponding parts in the
several Figures.
In Sheet II. Figure 5 is a longitudinal section of a rock drilling
engine of the same construction, having my improved apparatus applied
to it, and Figure 6 is a sectional plan of part of the same; Figure 7 is
an end view of the same from the back.
Figures 8 and 9 shew modified arrangements of the valve shewn in
Figure 3, Sheet I.
a is the large cylinder of the rock drilling engine;
6, 6, are the pistons working in it, and c is the screw for feeding the
cylinder forward; d is the smaller cylinder shewn attached to the
cylinder cover e, and f is the piston working in it, and having pieces of
wood or other sufficiently elastic substance let into its ends to receive
the force of any blow against the ends of the cylinder d. The ratchet
wheel g upon the screw c is driven by the arm i and the pall k.
In Figures 1, 2, and 3, Sheet I., the outer end of the arm i is shewn
passing through a slot in the cylinder d, and entering the annular
groove in the piston f, by which the arm is driven backward and
forward.
In Figures 5, 6, and 7, Sheet II., the ratchet wheel g is shewn having
teeth upon its edge which are driven by the pall which slides in a
transverse hole or recess in the piston f, and is forced out against the
ratchet wheel by a spring in the bottom of the recess. A handle is
shewn fixed to the pall and passing through a slot in the cylinder, so
that by it the pall k may be drawn out of gear with the ratchet wheel g
when required.
In Figures 1, 2, 3, 4, and 6 m is a passage through the cylinder
cover e communicating with the outer end of the cylinder a, and n is a

page_text: passage communicating with the other or inner end of the cylinder a
(as shewn in Figure 4), and having fitted in it upon a seat at its inner
end the valve o which is pressed down by a spring. The valve o has a
projection p (Figures 3 and 4) which is struck when necessary by the
piston b. If the piston b does not penetrate the rock sufficiently to lift
the valve o, steam is not admitted into the passage n, and consequently
the small piston d does not make a stroke.
Figure 8 shews the valve o arranged in a different manner, so as to be
inclined to the bore of the cylinder a. The edge of the valve o projects
into the cylinder sufficiently for the piston to lift it, but its angle of
inclination allows the edge of the piston to travel completely past it.
Figure 9 shews the valve o without any projection, but of sufficient
diameter itself to project into the cylinder a, and be lifted by the piston
in the latter.
The dotted lines in Figure 4, Sheet I., shew another arrangement
which I sometimes use for the same purpose, in which no valve is
required. 8 is an annular recess formed round the outer piston b¹, and
communicating by the passage t (formed in the piston rod) with the
steam space upon the inner side of the piston b. The passage n (instead
of being carried on to the inner end of the cylinder n, and containing a
valve) terminates in a port into the cylinder nearly opposite to the
annular recess, as shewn in dotted lines at v.
When the drill penetrates sufficiently for the piston 61 to bring the
recess s opposite the port v, the steam (or other fluid) has access to the
back of the small piston d, which accordingly makes its return stroke as
already described. If the piston 61 does not travel sufficiently far, the
port remains closed, and the small piston is not moved. In this
arrangement I prefer to give the circular angular motion which the
pistons and drill require to have at or between each stroke by means of
longitudinal helical grooves or recesses formed upon the piston rod at
the part w (Figure 5), and I make a catch or detent fitting into a recess
formed in the cylinder at the part within which the part w works, and
turning upon a pivot parallel with the piston rod. The other end of
this catch or detent I connect to a small piston working in a short
cylinder at right angles to the piston rod, so that when the steam is
admitted to the inner end of the principal cylinder the small piston is
forced out, and brings the catch or detent into contact with the helical

page_text: grooves. Un the return stroke of the drill the catch or detent is
removed from the helical groove by a spring arranged above the small
piston. Or the catch or detent may be formed upon the small piston
itself, and be put into operation when the latter is forced down, and
released when it is forced up, and it operates upon a ring having notches
at its circumference, and having a tooth working in a longitudinal slot
in the piston rod, so that the latter may be turned when the ring is
turned, though the ring is allowed no longitudinal movement. Or the
ring may be made without notches on its circumference, and may be
held firm merely by the pressure of the small piston upon it by means
of steam or springs. I prefer to use this arrangement in combination
with a twisted helical bar and ratchet wheel, arranged as described and
shewn in the Specification of my Patent dated February 13th, A.D.
1873, and numbered 541, already referred to.
A is a
Figures 10 and 11, Sheet II., are in illustration of this arrangement;
Figure 10 is a longitudinal section, and Figure 11, a transverse section
of the cylinder shewn in Figures 5 and 6. a is the cylinder; 6 is the
piston rod to which the drill is attached; a is a longitudinal groove or
keyway into which the tongue y upon the loose ring fits.
small cylinder containing the piston B, which is pressed against the
ring by steam admitted through the passage C, which communicates
with the other end of the cylinder a. The ring can turn round freely,
but it prevented from moving endways by a tongue upon the piston B,
and by the screw D which enter a groove formed in the edge of the
ring.
I sometimes allow the exhaust steam or air to escape from the
principal cylinder, where two pistons are used, by forming exhaust ports
through the cylinder immediately outside each piston when at the inner
end of its stroke. The piston then uncovers the exhaust port so formed,
and immediately uncovers it again on commencing its return stroke.
In order to fix the drill to the piston rod, which is made hollow for a
sufficient depth, I prefer to use the arrangement shewn in longitudinal
section in Figure 12, and in cross section in Figure 13, Sheet II., in
which E is the outer end of the piston rod; F is the drill fitting within
the rod E. A transverse slot G is made partly or entirely through the
piston rod E near its outer extremity, and into it is fitted the loop or clip
through which the drill passes and is tightened by means of the

page_text: wedge or key I which is driven between the loop H and the piston
rod E, so that its momentum has a tendency to tighten it at each stroke.
The drill bar is made slightly smaller in diameter where the loop fits
it, and when necessary it may be drawn out and refixed with or without
a temporary bar or stopping piece placed below it in the piston rod.
Having now described my Invention and the manner in which it is to
be performed, I claim,―
The combination of the wheel upon the feed screw of rock drilling
engines, with the supplementary cylinder and piston actuated as
described, and driving the wheel by means of a pall, substantially as 1
described and shewn in the Drawings.
Also, the methods of preventing the feed screw of rock drilling engines
from rotating too quickly where the penetration of the drill is insufficient,
substantially as described and shewn in the Drawings.
Also, the loose ring with a key working in a groove in the piston 1
rod of rock drilling engines in combination with a cylinder, piston, and
steam passage or spring, for the purpose of guiding the piston rod, and
the loose clip and wedge for attaching the drill to the piston rod, sub-
stantially as described and shewn in the Drawings.
Also, the method of allowing the exhaust steam to escape through:
ports uncovered by the pistons at the inner end of their stroke, sub-
stantially as described.
In witness whereof, I, the said Edmund Edwards, have hereunto
set my hand and seal, this Sixth day of October, in the year of
our Lord One thousand eight hundred and seventy-three.
EDMUND EDWARDS. (LS.)