IMPROVEMENTS IN THE CONSTRUCTION OF ENGINES DRIVEN BY STEAM, COMPRESSED AIR, OR OTHER ELASTIC FLUID OR
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 THE CONSTRUCTION OF
ENGINES DRIVEN BY STEAM, COMPRESSED AIR, OR OTHER ELASTIC FLUID, OR
Sealed the 9th May 1873, and dated the 13th February 1873.
PROVISIONAL SPECIFICATION left by the said Edmund Edwards at
the Office of the Commissioners of Patents, with his Petition, on
the 13th February 1873.
I, EDMUND EDWARDS, of 38, Southampton Buildings, Chancery Lane,
in the County of Middlesex, Engineer and Patent Agent, do hereby
declare the nature of the said Invention 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," to be
as follows:-
-
My improvements relate especially to apparatus intended for drilling
holes in rocks or other analogous hard substances by means of the force
of steam, compressed air, or other elastic fluid operating upon a piston
A

page_text: which is thus caused to reciprocate backwards and forwards within a
cylinder, and which has connected to it a metal drill.
The first part of my Invention relates to improved forms and
arrangements of valves and cylinders for the purpose of causing the
piston and drill described to reciprocate, by which improved forms and
arrangements there is less friction, greater simplicity of parts, and
increased cheapness in construction, and efficiency in working, with
greater durability of the apparatus.
The second part of my Invention relates to improved methods of
giving in rock drilling engines the required circular angular motion to
the drill at or after each stroke, and of feeding the drill forward as the
depth increases of the hole which is being drilled, and of fixing the
engine in its position when at work.
The body of the apparatus consists of the cylinder or cylinders in
which the piston or pistons herein-after described are caused to
reciprocate backwards and forwards in the usual way. This body of
the apparatus when used for rock drilling may be supported in a suitable
frame or stand so arranged that the direction of the hole which is to be
made by the drill may be varied, and also so that the body of the
apparatus or cylinder may be moved forward by degrees as the depth
of such hole increases.
In apparatus constructed as and for the purpose required it is found
advisable that the piston (which drives the drill) should be forced forward
with the full pressure of the steam behind it, but that for the purpose
of withdrawing the drill a less pressure in front of the piston is required,
and accordingly a piston rod of large diameter passing through a
suitable stuffing box or its equivalent is used, so that the effective area of
the front of the piston is considerably reduced.
One novel form of cylinder by which the same result is obtained
without the use of a stuffing box I construct as follows:- I take two
cylinders arranged in line with one another but of different diameters,
and I fit a piston into each cylinder, which pistons aro rigidly and
firmly attached together or they may be made of one piece. To the
piston in the smaller cylinder the drill is attached without the inter-
vention of a stuffing box. Steam (or other elastic fluid) is admitted
through a suitable passage which is kept constantly open between the
two pistons, and the space above the larger piston is made to

page_text: communicate alternately with the steam supply pipe and with the open
air or a discharge pipe. By this arrangement when steam is admitted
above the larger piston the pistons are forced down with a pressure
proportioned to the area of the smaller piston, and when the steam is
discharged from above the larger piston the pistons are forced up with
a pressure proportioned to the difference in area between the two
pistons.
In order to make the upper part of the large cylinder communicate
alternately with the steam supply pipe and with the open air I close the
upper part of the cylinder with a cylindrical valve or plug fitting steam
tight or nearly so, and moveable vertically in the cylinder for a short
distance, and I arrange this valve so that when it is at the top of its
stroke its lower edge uncovers a port in the cylinder which admits
steam, and when it is at the bottom of its stroke the steam port is closed
and an eduction port is opened through the body and circumference of
the valve.
The steam and eduction ports may be composed of a series of openings
round the entire circumference of the cylinder and valve. And in order
to actuate the valve described I use a tappet rod formed upon or
attached to the upper piston, and passing through a suitable aperture
in the valve, with or without a stuffing box or other means for
preventing the escape of steam. The valve is moved at the top and
bottom of its stroke by being struck by the tappets upon the rod.
Sometimes for the same purpose I close the top of the upper
cylinder and use a slide valve, covering ports, so arranged that when
moved in one direction a steam port is opened, communicating with
the top of the cylinder, and when struck in the other direction the
steam port is closed and an eduction port is opened instead, for the
purposes already described, and I work such slide valve by means of.
tappets upon or connected with the piston.
Sometimes for the same purpose I use a cylindrical slide valve fitting
into one or other of the cylinders between the two pistons, such
cylinder being made of sufficient length for the purpose. In this
arrangement I make the cylindrical slide valve fit steam tight or nearly
so at its upper and lower edges, but I make its remaining part of less
diameter, and I make the rod connecting the two pistons pass freely
through an opening in the centre of the valve, through which (or

page_text: through other openings in the valve) steam can communicate between
the parts of the cylinder above and below the valve. And I make the
supply steam pipe communicate with the cylinder either above or below
the valve, and I arrange tappets upon the pistons, or upon the rod
connecting them, which strike the valve at each end of the stroke.
When the valve is moved upwards at the end of the upstroke of the
pistons I arrange the valve so that its lower edge uncovers a port or
series of ports which communicate with the larger cylinder above the
piston, and steam passing through this port the pistons and drill
immediately descend, as already described, and at the bottom of their
stroke they strike the valve down so that its lower edge closes the port
or ports described, and travelling past them puts them in communication
with the part of the valve which is of less diameter, and also with
another port or series of ports in the cylinder which communicate
directly with the open air or with a discharge pipe and are always
covered by the part of the valve of smaller diameter in whatever
position it may be. The pistons then make their upstroke in the way
already described, and the reciprocation continues constantly.
The central valve need not be cylindrical but its face may form a
segment of a cylinder, or may be flat, suitable ports, as described, being
formed for it to work upon, either in the cylinder or connected
with it.
Sometimes instead of the arrangement described I use the following
modification:- I arrange the larger cylinder below the smaller one, and
I close its lower end through which the piston rod passes by means of
a stuffing box or analogous arrangement, and I make the upper end of
the smaller cylinder open, and by means of a valve of a similar description
to those already described I retain the steam constantly between the
two pistons but open a communication between the lower end of the
larger cylinder and the inlet supply pipe and the outlet alternately.
When steam is admitted beneath the large piston the pistons and drill
rise, and when it is allowed to escape the pistons and drill are forced
down.
Where an ordinary cylinder is to be used having a piston reciprocating
within it by the pressure of steam admitted alternately to each end of
1
T

page_text: a cylinder having within it a piston attached to a rod which works
through a stuffing box (or other analogous arrangement for the same
purpose) at the lower end of the cylinder. The upper end of the
cylinder above the piston is continued upwards of the same or greater
diameter, and in it is fitted steam-tight or nearly so a cylindrical
valve which works vertically in the cylinder. The cylindrical valve
is made in a manner somewhat similar to that already described, but
there is no communication between the parts of the cylinder above
and below it, and in its lower edge (which is made sufficiently wido
for the purpose) is formed a port or series of ports which pass through
the body of the valve to openings at its upper surface. A tappet rod
similar to that already described passes through the body of the valve,
but the passage of steam is prevented or nearly so (in this form of
apparatus) by accurate fitting or by a stuffing box or other analogous
arrangement for the same purpose. A steam supply pipe communi-
cates through the side of the cylinder with the part of the valve which
is of less diameter, as already described, in whatever position the valve
may be, and a port is also formed at the side of the cylinder communi-
cating between the lower end of the cylinder and the annular space,
of less diameter round the valve when the latter is at the lower part
of its stroke, and between the lower end of the cylinder and the port
in its lower edge when it is at the upper part of its stroke. Thus,
the lower part of the cylinder communicates with the steam pipe when
the valve is down, and with the outlet when the valve is up. Another
port (or series of ports) is formed which communicates between the
upper part of the cylinder (below the valve) and the annular steam
space round the valve when the latter is up, and the outlet or open
part of the cylinder above the valve when it is down. By the arrange-
ment described the rapid alteration of the position of the cylindrical
valve when it is struck at the top and bottom of the stroke causes
the required reciprocation of the piston and piston rod with the drill
attached.
Anthon

page_text: described to fit and work in the part between the two pistons, and I
arrange the valve so that when it is raised its lower edge passes and
opens a port formed on one side of the cylinder, and communicating
with the part above the upper piston, and when the valve is depressed
its upper edge passes and opens a similar port formed upon another
part of the cylinder, and communicating with the part below the lower
piston; and I form one or more inlet steam passages in a suitable part
of the side of the cylinder, so that the space between the two pistons
is kept constantly filled with steam, and I form one or more outlet
steam ports in the cylinder in such a position as to be always in com-
munication with the annular space round the valve in whatever position
the latter may be.
Sometimes I arrange the apparatus so that the steam may be
admitted through what has been described as the outlet port, and
may be discharged through what has been described as the inlet port,
and in such case the passage from the upper part of the cylinder above
the top piston must communicate with the port which is opened when
the valve is depressed, and the passage from the lower part of the
cylinder below the bottom piston must communicate with the port
which is opened when the valve is raised, instead of vice versâ, as
already described. The valve is raised and depressed at the ends of the
stroke by being struck by the pistons, or by projections upon the rod
which connects the two pistons together.
In the arrangements last described instead of each end of the cylinder
being made to communicate alternately with an inlet and an outlet
port, the steam may be kept constantly below the lower piston, and only
a method of making a communication between the upper end of the
cylinder and the inlet and outlet ports alternately need be provided
by means of a suitable valve of a kind analogous to those already
described. The operation of this form of apparatus is similar to that
of the apparatus first described, the lower side of the bottom piston
having an effective area less than that of the top of the upper piston,
in proportion to the area of the piston rod, which may be made of any
desired size and proportion. By the arrangements described the valves
and methods of working them in rock drilling machines are much
simpler, cheaper, and more durable, and work with less friction than
in such machines as heretofore constructed. Suitable stops may be
used to limit the travel of the valves.

page_text: The arrangements described may also be applied to the construction
of engines worked by the pressure of steam, air, gas, water, or other
elastic or non-elastic fluid, and used for other purposes than the
actuating of drills, such as the measurement of fluids passing through
them, or driving machinery.
The second part of my Invention relates to improved methods of
giving the requisite circular angular motion to the drill at or after
each stroke, and of feeding the drill forward as the depth of the hole
which is being drilled increases. When the rock or other hard sub-
stance which is being drilled is not perfectly homogeneous in hardness,
I prefer that the drill should be fed forward by hand instead of by
any self-acting mechanism, and as the presence of an attendant with
the machine is in all cases advisable no disadvantage is experienced
by such hand regulation of the feed. In such cases I prefer to use
a screw turning in a bearing connected to the outer frame of the
machine, the screw being connected to the cylinder in such a manner
that the latter is moved forward a sufficient distance in the frame
which carries it every time the screw is turned. Or instead of the
screw being turned round it may work in a nut supported by the
outer frame and made to turn as required, and thus to force the screw
and cylinder forward. Where however it is preferred to make the screw
or nut revolve by means of self-acting machinery, any of the methods
well known and practised for the purpose may be used, but the following
is a novel arrangement which I prefer to use :-I arrange the nut so
that it can revolve in a collar attached to the cylinder in a suitable
position, and I attach to the nut a bevil toothed wheel driven by
another bevil toothed wheel to which a ratchet wheel is attached;
and I form a sliding piece having a tooth or pall which acts upon
the ratchet wheel when the sliding piece is pushed backward, and
upon the sliding piece I form two projecting pieces which are struck
by a tappet connected with the piston, so that the sliding piece is
driven backward and forward by the reciprocation of the piston. If
from any cause any stroke of the drill penetrates the rock so slightly
that it is not advisable to feed the cylinder forward, the sliding piece
is not drawn sufficiently forward (at such blow of too little penetration)
for the pall to catch the next succeeding tooth of the ratchet wheel, and
accordingly when driven back it does not act upon the latter, and the
cylinder is consequently not propelled forward.

page_text: Another novel form of arrangement which I use for the same purpose
consists in carrying backwards a bar or ram connected to the cylinder,
and working in a hydraulic cylinder fitted with suitable valves, and
with a small plunger which at each stroke of the piston and drill is set
in motion by them so as to force a sufficient quantity of water into the
hydraulic cylinder, and thus propel the drill cylinder forward.
Sometimes instead of supporting the drill cylinder in guides only
allowing an end motion, I support it in tubular guides so arranged that
it can be turned round and at the same time forced forward (suitable
provision being made for the steam supply pipe). In this way, when
the screw is turned round the required feed is given, and at the same
time the circular angular movement required by the drill is given
(guides being provided to ensure the piston and drill turning as well as
the cylinder). Where such circular angular movement is required to be
greater than the circular angle through which the screw has to be
moved for the purpose of forcing the cylinder foward, I use a double
screw having upon one part of its length a screw of greater and opposite
pitch to that of a screw upon the other part of its length. And I make
one screw work through a fixed nut carried by the frame which supports
the cylinder, and the other through a nut connected to the cylinder.
By this arrangement the cylinder is drawn back by the finer pitched
screw a part of the space which it is forced forward by the coarser
pitched screw.
Sometimes in order to give the pistons and drill the necessary angular
circular motion round their centre I fit the circular valve already
described upon the central rod or bar so that neither can turn without
the other, and I form the exhaust ports in the valve with straight or
curved tangential apertures, so that the reaction of the steam during its
emission may cause the valve and with it the piston and drill to revolve
sufficiently, and I limit or regulate the amount of such revolution by
means of friction or other stops suitably arranged.
Or sometimes I make a bar preferably hexagonal or polygonal in
section, and having a spiral twist or circular in section, but having a key
way or feather fitted spirally upon it, and I make a corresponding nut
which I attach to the upper piston, and I fix the outer bar in such a
manner that when the piston rises it is caused to turn partially round as
the nut rises on the bar (which may enter a suitable hole bored in the

page_text: piston and piston rod), and I form a ratchet wheel upon the nut into
which a pall attached to the piston works, so that the piston may descend
without any circular motion being imparted to it, and where advisable
I form the piston rod between the two pistons (where two are used as
already described) or the piston rod outside the cylinder, into the form
in cross section of a ratchet wheel having its teeth made in the opposite
direction to those upon the nut, and I attach a spring pall which works
in such teeth to the cylinder, and I thus prevent the piston rod and drill
from turning backward.
Sometimes I form one or more spiral slots or feathers upon or
connected to the cylinder which guide a cross head fitted loosely upon
the tappet rod already described. Suitable ratchets working in one
another are fitted upon the cross head and upon the tappet bar, so that
when the piston rises it is made to turn partially round by the action of
the spiral guides upon the cross head, but when it falls the ratchets-
upon the tappet bar become disengaged from those upon the cross head,
and the piston descends without being turned round.
Sometimes I feed the cylinder forward by forming a toothed rack
upon the frame which supports it, and fitting a toothed pinion working
in such rack and carried by a spindle supported in bearings attached to
the cylinder. To the spindle is connected a tangent wheel driven by a
screw turned by hand, and the cylinder is thus fed forward as required.
I prefer to make the toothed rack so narrow transversely that the wheel
and spindle can be drawn endways until out of gear with it, or to make
the screw removeable from the tangent wheel, and the cylinder can be
then instantly removed from the frame in which it is supported.
In order to attach the frame which supports the cylinder to standards
by which the entire apparatus is carried, any of the methods well known
and practised may be used, but I prefer to use an arrangement con-
structed as follows:-The standards supporting the entire apparatus have
formed upon or attached to them a segment of a sphere of sufficient size
and diameter. Upon the frame supporting the cylinder is formed or
attached a bracket which rests upon the spherical segment, and consists
of three bearing surfaces, feet, or projections, equidistant or nearly so
from one another. A bolt connects the spherical segment and the three
bearing surfaces together, and is tightened or loosened as required by
means of a nut or key. By this arrangement the frame and cylinder

page_text: can be turned completely round in a plane parallel with that of the three
bearing surfaces, and it can also be sufficiently adjusted in either
direction laterally, as may be required. The spherical surface may
be made upon the frame, and the three bearing surfaces upon the
standards.
In order to make the piston rod pass steam tight through the lower
end of the cylinder where necessary in the different arrangements
described in the former part of my Specification, a stuffing box having
a moveable gland such as is ordinarily used in steam cylinders may be
used, or one or more grooves may be made surrounding the piston rod
in the opening in the cylinder through which the rod passes, and these
grooves may be made to contain metallic, leather, or other rings, which
serve as packing behind which steam may be admitted if necessary.
The upper end of the opening may be made tapering to admit the
rings.
I prefer, however, to make the stuffing box of the greatest diameter at
the end opening into the cylinder, and to fit into it from inside a collar
of leather, metal, or other suitable substance of sufficient flexibility
surrounding the piston rod against which it is pressed by the steam.
The lower or inner end of the collar may be flanged over and held in its
place by an internal ring and screws or bolts; or the collar may bo
flanged both above and below, and may be fitted in a recess into which
steam is admitted behind it.
Sometimes I make the stuffing box of a length somewhat greater
than the stroke of the piston, and I bore it out to fit the piston rod
round which I make one or more grooves into which metallic or other
packing rings are fitted, which work against the inside of the stuffing
box.
In some cases I make the piston rod of larger diameter where the
packing rings are fitted, so as to become in effect a supplementary
piston, which may be used instead of making the piston rod itself of
considerable diameter in order to reduce the effective area of the lower
side of the principal piston, as described in the first part of my
Invention.
In order to avoid the necessity for substituting a longer drill when the
full depth of hole has been made which the forward feeding arrangement
of the apparatus will allow, I sometimes make the piston rod hollow, and

page_text: I arrange the drill bar inside it, and attach them together by means of a
suitable screw, bolt, or clamp. When the cylinder has been fed forward
as far as possible I detach the drill bar and then bring back the cylinder
to its former position, the drill bar being at the same time withdrawn
from the hollow piston rod, and I then attach them together again and
recommence the operation of drilling.
Where my apparatus is used for the purpose of cutting coal in
collieries, I sometimes use one cylinder, but I prefer to use two or more
cylinders made in one casting or attached to the same frame, and
carrying drills which strike the coal (but to which it is not necessary to
give a circular angular motion). These cylinders are carried upon a
frame supported upon wheels or guides in such a manner that a
horizontal or vertical motion at right angles to the drills and parallel to
the face of the coal can be given to it. A sufficient number of drills are
used to make a cut of the depth required, each succeeding drill being of
greater length than the one immediately in advance of it. The drills
may have cutting edges of a width greater than the outer diameter of
the cylinders, so that the latter may themselves be made to follow the
drills into the cut as its depth increases.
The pistons in the cylinders may be actuated by the methods already
described, or by any other of the methods ordinarily used and practised.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edmund Edwards in the Great Seal Patent Office
on the 13th August 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDMUND
EDWARDS, of 38, Southampton Buildings, Chancery Lanc, 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 Thirteenth day of February, 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 licenco
that I, the said Edmund Edwards, my executors, administrators, and

page_text: 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 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 THE
CONSTRUCTION OF ENGINES DRIVEN BY STEAM, COMPRESSED AIR, OR OTHER ELASTIC
FLUID, OR BY WATER, ESPECIALLY APPLICABLE TO ROCK BORING ENGINES," upon
the condition (amongst others) that I, the said Edmund Edwards, my
executors or administrators, 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 within six calendar months next and
immediately after the date of the said Letters Patent.
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 improvements relate especially to apparatus intended for drilling
holes in rocks or other analogous hard substances by means of the force
of steam, compressed air, or other elastic fluid operating upon a piston,
which is thus caused to reciprocate backwards and forwards within a
cylinder, and which has connected to it a metal or other suitable 2
drill.
The first part of my Invention relates to improved forms and arrange-
ments of valves and cylinders for the purpose of causing the piston and
drill described to reciprocate, by which improved forms and arrange-
ments there is less friction, greater simplicity of parts, and increased 3
cheapness in construction and efficiency in working, with greater dura-
bility of the apparatus.
The second part of my Invention relates to improved methods of
giving in rock drilling engines the required circular angular motion to
the drill at or after each stroke, and of feeding the drill forward as the 3
depth increases of the hole which is being drilled, and of fixing the
engine in its position when at work.

page_text: The body of the apparatus consists of the cylinder or cylinders, in
which the piston or pistons herein-after described are caused to recipro-
cate backwards and forwards in the usual way. This body of the
apparatus when used for rock drilling may be supported in a suitable
frame or stand so arranged that the direction of the hole which is to be
made by the drill maybe varied, and also so that the body of the apparatus
or cylinder may be moved forward by degrees as the depth of such hole
increases.
In apparatus constructed as and for the purpose required it is found
advisable that the piston (which drives the drill) should be forced forward
with the full pressure of the steam behind it, but that for the purpose of
withdrawing the drill a less pressure in front of the piston is required,
and accordingly a piston rod of large diameter passing through a suitable
stuffing box is used, so that the effective area of the front of the piston
is considerably reduced.
One novel form of cylinder by which the same result is obtained
without the use of a stuffing box I construct as follows:-I take two
cylinders (shewn at a, b, in Figure 1, on the accompanying Drawing,
Sheet I.), arranged in line with one another but of different diameters;
and I fit a piston into cach cylinder, which pistons c, d, are rigidly and
firmly attached together, or they may be made of one piece. To the
piston in the smaller cylinder the drill is attached without the inter-
vention of a stuffing box. Steam (or other clastic fluid) is admitted
through a suitable passage e, which is kept constantly open between the
two pistons, and the space above the larger piston is made to communi-
cate alternately with the steam supply pipe f, and with the open air or
a discharge pipe at g. By this arrangement when steam is admitted
above the larger piston the pistons are forced down with a pressure pro-
portioned to the area of the smaller piston and when the steam is
discharged from above the larger piston the pistons are forced up
with a pressure proportioned to the difference in area between the two
pistons.
In order to make the upper part of the large cylinder communicate
alternately with the steam supply pipe and with the open air I close
the upper part of the cylinder with a cylindrical valve or plug / fitting
steam-tight, or nearly so, and moveable vertically in the cylinder for a
short distance; and I arrange this valve so that when it is at the top of

page_text: its stroke its lower edge uncovers a port i in the cylinder, which admits
steam, and when it is at the bottom of its stroke the steam port is closed,
and an eduction port j is opened through the body and circumference of
the valve.
The steam and eduction ports may be composed of a series of openings
round the entire circumference of the cylinder and valve, as shown.
And in order to actuate the valve described I use a tappet rod / formed
upon or attached to the upper piston, and passing through a suitable
aperture in the valve with or without a stuffing box or other means for pre-
venting the escape of steam. The valve is moved at the top and bottom
of its stroke by being struck by tappets or collars 1, 1, upon the rod.
Sometimes for the same purpose I close the top of the upper cylinder,
and use a slide valve, covering ports so arranged that when moved in
one direction a steam port is opened communicating with the top of the
cylinder, and when struck in the other direction the steam port is
closed, and an eduction port is opened instead for the purposes already
described; and I work such slide valve by means of tappets upon or
connected with the piston.
Sometimes for the same purpose I use a cylindrical slide valve fitting
into one or other of the cylinders between the two pistons, such cylinder
being made of sufficient length for the purpose. In this arrangement I
make the cylindrical slide valve fit steam-tight, or nearly so, at its upper
and lower edges, but I make its remaining part of less diameter; and I
make the rod connecting the two pistons pass freely through an opening
in the centre of the valve, through which (or through other openings in
the valve) steam can communicate between the parts of the cylinder
above and below the valve. And I make the supply steam pipe com-
municate directly with the cylinder either above or below the valve; and
I arrange tappets upon the pistons, or upon the rod connecting them,
which strike the valve at each end of the stroke. When the valve is
moved upwards at the end of the up stroke of the pistons I arrange the
valve so that its lower edge uncovers a port or series of ports which
communicate with the larger cylinder above the piston, and steam
passing through this port the pistons and drill immediately descend, as
already described; and at the bottom of their stroke they strike the
valve down, so that its lower edge closes the port or ports described,
and travelling past them puts them in communication with the part of

page_text: the valve which is of less diameter, and also with another port or series
of ports in the cylinder which communicate directly with the open air
or with a discharge pipe, and are always covered by the part of the
valve of smaller diameter in whatever position it may be. The pistons
then make their up stroke in the way already described, and the recipro-
cation continues constantly.
upon
The central valve need not be cylindrical, but its face may form a
segment of a cylinder (a portion being removed, so that the valve can
readily be removed from the central piston rod or tappet rod), or may be
flat, suitable ports as described being formed for it to work inside
the cylinder, or the valve and cylinder may be made as shewn in
Figures 12, 13, and 14, in which the steam inlet passage f is formed
directly opposite the outlet passage g, an opening o being made through
the valve, so that the outlet passage 7 may communicate through the
opening o with the space between the two pistons.
Sometimes instead of the arrangement described I use the following
modification:-I arrange the larger cylinder below the smaller one, and
I close its lower end, through which the piston rod passes by means of a
stuffing box or analogous arrangement, and I make the upper end of the
smaller cylinder open; and by means of a valve of a similar description
to those already described I retain the steam constantly between the two
pistons, but open a communication between the lower end of the larger
cylinder and the inlet supply pipe and the outlet alternately. When
steam is admitted beneath the large piston the pistons and drill risc, and
when it is allowed to escape the pistons and drill are forced down.
Where an ordinary cylinder is to be used having a piston reciprocating
within it by the pressure of steam admitted alternately to each end of
the cylinder, I use an arrangement of valve somewhat similar to the
cylindrical valve already described, as shewn in Figure 2. In this form
of arrangement I take a cylinder a having within it a piston 6 attached
to a rod c which works through a stuffing box (or other analogous
arrangement for the same purpose) at the lower end of the cylinder.
The upper end of the cylinder above the piston is continued upwards of
the same or greater diameter, and in it is fitted steam tight or nearly so
a cylindrical valve d which works vertically in the cylinder. The
cylindrical valve is made in a manner somewhat similar to those already
described, but there is no communication between the parts of the

page_text: cylinder above and below it, and in its lower edge (which is made
sufficiently wide for the purpose) is formed a port or series of ports e
which pass through the body of the valve to openings at its upper
surface. A tappet rod similar to that already described passes
through the body of the valve, but the passage of steam is prevented or
nearly so (in this form of apparatus) by accurate fitting or by a stuffing
box or other analogous arrangement for the same purpose. A steam
supply pipe f communicates through the side of the cylinder with the
part of the valve which is of less diameter, as already described in
whatever position the valve may be, and a port g is also formed at the
side of the cylinder communicating between the lower end of the
cylinder and the annular space of less diameter round the valve, when
the latter is at the lower part of its stroke and between the lower end of
the cylinder and the port in its lower edge when it is at the upper part
of its stroke. Thus the lower part of the cylinder communicates with
the steam pipe when the valve is down and with the outlet when the
valve is up. Another port % (or series of ports) is formed which com-
municates between the upper part of the cylinder (below the valve), and
the annular steam space round the valve when the latter is up, and the
outlet or open part of the cylinder above the valve when it is down. A
spring may be used to keep the valve down when the piston is rising.
By the arrangement described the rapid alteration of the position of the
cylindrical valve, when it is struck at the top and bottom of the stroke,
causes the required reciprocation of the piston and piston rod with the
drill attached.
Another arrangement which I adopt is to make the cylinder a (as
shewn in Figures 3, 4, 5, 17, and 18), of sufficient length to contain two
pistons b, b¹, of the same diameter connected together as in the arrange-
ment first described, but having the piston rod c passing at the lower
end through a stuffing box d or other analogous arrangement for the
same purpose. I make the cylinder sufficiently long to allow a cylin-
drical valve e, of a kind similar to those already described, to fit and
work in the part between the two pistons, and I arrange the valve as
shewn in Figures 17 and 18 on Sheet II., so that when it is raised its
lower edge passes and opens a port g formed on one side of the cylinder,
and communicating with the part above the upper piston b', and when
the valve is depressed its upper edge passes and opens a similar port /
formed upon another part of the cylinder, and communicating with the

page_text: part below the lower piston 6; and I form one or more inlet steam
passages i in a suitable part of the side of the cylinder, so that the space
between the two pistons is kept constantly filled with steam; and I form
one or more outlet steam ports k in the cylinder in such a position as to
be always in communication with the annular space round the valve e¹
in whatever position the latter may be. Figure 19 shews an end view
from the top of a cylinder constructed and arranged in this manner;
Figure 20 is a cross section of the same cylinder through the line c, d,
on Figure 17; and Figures 21 and 22 are cross sections of the same
cylinder through the lines e, f, and A, B, respectively, on Figure 17.
The valve in this arrangement is made split at one side (as shewn in end
view in Figure 25) so that the pressure of the steam may keep it tight
against the cylinder.
Sometimes I arrange the apparatus (as shown in Figure 3, Sheet I.)
so that the steam may be admitted through what has been described as
the inlet port g, and in such case the passage.h from the upper part of
the cylinder above the top piston must communicate with the port i
which is opened when the valve is depressed and the passage k from the
lower part of the cylinder below the bottom piston must communicate
with the port / which is opened when the valve is raised instead of vice
versâ as already described. The valve is raised and depressed at the ends
of the stroke by being struck by the pistons or by collars or projections
m, m', upon the rod which connects the two pistons together. The
central part of the valve may be omitted altogether, its outer circum-
ference being struck by the collars or projections upon the rod.
In the arrangements last described, instead of each end of the cylinder
being made to communicate alternately with an inlet and an outlet port,
the steam may be kept constantly below the lower piston, and only a
method of making a communication between the upper end of the
cylinder and the inlet and outlet ports alternately need be provided by
mcans of a suitable valve of a kind analogous to those already described.
The operation of this form of apparatus is similar to that of the apparatus
first described, the lower side of the bottom piston having an effective
area less than that of the top of the upper piston in proportion to the
area of the piston rod, which may be made of any desired size and pro-
portion. By the arrangements described, the valves and methods of
working them in rock drilling machines are much simpler, cheaper, and
B

page_text: more durable and work with less friction, and the action of the valves is
more instantaneous than in such machines as heretofore constructed,
whilst the ports and steam passages can be made larger ‍than usual.
The arrangements described may also be applied to the construction of
engines worked by the pressure of steam, air, gas, water (in which case
I use air vessels to continue the movement of the pistons after the
admission port is closed), or other elastic or non-elastic fluid, and used
for other purposes than the actuating of drills, such as the measurement
of fluids passing through them, or driving machinery, as shewn in
Figure 15, which represents a direct acting pumping engine, and
Figure 16, which represents a rotatory engine with an oscillating
cylinder. In addition to valves described and shewn, cut-off valves for
working such engines expansively may also be used. Suitable stops n
may be used to limit the travel of the valves.
Sometimes instead of the valves described I use a four-way cock for. 1
the purpose of admitting the steam alternately to each end of the
cylinders, and I make the aperture which forms the exhaust passage of
the four-way cock communicate directly with the space between the
pistons, and large enough to allow a rod or lever attached to the plug of
the cock to pass through it and to be struck backward and forward at 2
each end of the stroke by the pistons or by projections upon them.
'
The second part of my Invention relates to improved methods of
giving the requisite circular angular motion to the drill at or after each
stroke, and of feeding the drill forward as the depth of the hole which
is being drilled increases. Where the rock or other hard substance 2
which is being drilled is not perfectly homogeneous in hardness, I prefer
that the drill should be fed forward by hand instead of by any self-acting
mechanism, and as the presence of an attendant with the machine is in
all cases advisable no disadvantage is experienced by such hand regula-
tion of the feed. In such cases I prefer to use a screw, shewn at o in 3
Figures 4, 5, 9, 11, 17, 19, and 22, turning in bearings p, p¹, connected
to the outer frame q of the machine (or to the cylinder), the screw being
connected to the cylinder (or to the frame) by the nut r, which can be
thrown in out of gear with the screw, as shewn in Figures 9, 11, 17,
and 19, or by the screw tangent wheel z,'as shewn in Figure 4, in such a 3
manner that the cylinder is moved forward a sufficient distance in the
frame which carries it every time the screw is turned. Or, instead of

page_text: the screw being turned round it may work in a nut supported by the outer
frame, and made to turn as required, and thus to force the screw and
cylinder forward. Where, however, it is preferred to make the screw or
nut revolve by means of self-acting machinery, any of the methods well
known and practised for the purpose may be used, but the following is
an arrangement which I sometimes use:-I arrange the nut so that it
can revolve in a collar attached to the cylinder in a suitable position,
and I attach to the nut a bevil toothed wheel driven by another bevil
toothed wheel to which a ratchet wheel is attached, and I form a sliding
piece having a tooth or pall which acts upon the ratchet wheel when the
sliding piece is pushed backward, and upon the sliding piece I form two
projecting pieces which are struck by a tappet connected with the piston,
so that the sliding piece is driven backward and forward by the recipro-
cation of the piston. If from any cause any stroke of the drill penetrates
the rock so slightly that it is not advisable to feed the cylinder forward,
the sliding piece is not drawn sufficiently forward (at such blow of too
little penetration) for the pall to catch the next succeeding tooth of the
ratchet wheel, and accordingly when driven back it does not act upon
the latter, and the cylinder is consequently not propelled forward.
Another arrangement which I use for the same purpose consists in
carrying backwards a bar or ram connected to the cylinder and working
in a hydraulic cylinder fitted with suitable valves and with a small plunger
which at each stroke of the piston and drill is set in motion by them so
as to force a sufficient quantity of water into the hydraulic cylinder and
thus propel the drill cylinder forward, or the cylinder may be connected
to a supply of water under pressure to which a regulated admission can
be given as required.
Sometimes instead of supporting the drill cylinder in guides only
allowing an end motion I support it in tubular guides, so arranged that
it can be turned round and at the same time forced forward (suitable
provision being made for the steam supply pipe). In this way when the
screw is turned round the required feed is obtained and at the same time
the circular angular movement required by the drill is given (guides
being provided to ensure the piston and drill turning as well as the
cylinder). Where suchcir cular angular movement is required to be
greater than the circular angle through which the screw has to be moved
for the purpose of forcing the cylinder forward I use a double screw,
having upon one part of its length a screw of greater, and opposite pitch
B 2

page_text: to that of a screw upon the other part of its length. And I make one
screw work through a fixed nut carried by the frame which supports the
cylinder and the other through a nut connected to the cylinder. By this
arrangement the cylinder is drawn back by the finer pitched screw a
part of the space which it is forced forward by the coarser pitched screw.
Sometimes in order to give the pistons and drill the necessary angular
circular motion round their centre I fit the circular valve already
described upon the central rod or bar so that neither can turn without
the other, and I form the exhaust ports in the valve with straight or
curved tangential apertures so that the reaction of the steam during its
emission may cause the valve and with it the piston and drill to revolve
sufficiently, and I limit or regulate the amount of such revolution by
means of friction or other stops suitably arranged.
Or sometimes I make a bar, preferably square, hexagonal, or polygonal,
in section and having a spiral twist, as shewn at 8, in Figures 3, 6, and
17, or circular in section but having a keyway or feather fitted spirally
upon it; and I make a corresponding nut t, Figures 6, 7, and 17, which
I attach to the upper piston, and I fix the outer bar in such a manner
that when the piston rises it is caused to turn partially round as the nut
rises on the bar (which may enter a suitable hole bored in the piston and
piston rod), and I form a ratchet wheel upon the nut into which a
pall w attached to the piston works, so that the piston may descend
without any circular motion being imparted to it.
Sometimes I form one or more spiral slots or feathers, shewn at v, v,
in Figures 2 and 8, upon or connected to the cylinder, which guide a
cross head w fitted loosely upon the tapped rod already described.
Suitable ratchets a working in one another are fitted upon the cross head
and upon the tappet bar, so that when the piston rises it is made to turn
partially round by the action of the spiral guides upon the cross head,
but when it falls the ratchets upon the tappet bar become disengaged
from those upon the cross head and the piston descends without being.
turned round.
Where a bar or bars having a spiral twist are used as and for the
purpose described I make the spiral part end at a sufficient distance
from the outer end, and I make it then gradually become straight, or
nearly so, for the remainder of its length. In this way the circular
angular movement of the piston is gradually commenced and stopped,

page_text: and the possibility of the movement being continued too far is reduced,
and the apparatus is rendered more durable from the absence of shock.
Sometimes I feed the cylinder forward by forming a toothed rack upon
the frame which supports it and fitting a toothed pinion working in
such rack and carried by a spindle supported in bearings attached to the
cylinder; to the spindle is connected a tangent wheel, driven by a screw
turned by hand, and the cylinder is thus fed forward as required. I
prefer to make the toothed rack so narrow transversely that the wheel
and spindle can be drawn endways until out of gear with it, or to make
the screw removeable from the tangent wheel, and the cylinder can be
then instantly removed from the frame in which it is supported.
In order to attach the frame which supports the cylinder to standards
by which the entire apparatus is carried any of the methods well known
and practised may be used, but I prefer to use an arrangement con-
structed as follows, and shewn in Figures 9, 10, 17, 19, 23, and 24 : —
The frame q supporting the cylinder has formed upon or attached to it
a segment of a spheres of sufficient size and diameter. Upon the
standard t supporting the entire apparatus is formed or attached a
bracket which rests upon the spherical segment and consists of three
bearing surfaces, feet, or projections wo, w, wo, equidistant, or nearly so,
from one another; a bolt x connects the spherical segment and the three
bearing surfaces together, and is tightened or loosened as required by
means of a nut or key. By this arrangement the frame and cylinder
can be turned completely round in a plane parallel with that of the three
bearing surfaces, and it can also be sufficiently adjusted in either direction
laterally as may be required. The spherical surface may be made upon
the standard, and the three bearing surfaces upon the frame, as shewn
in Figures 17, 19, 23, and 24.
In order to make the piston rod pass steam-tight through the lower
end of the cylinder where necessary, in the different arrangements
described in the former part of my Specification, a stuffing box having
a moveable gland such as is ordinarily used in steam cylinders may be
used, or one or more grooves may be made surrounding the piston rod in
the opening in the cylinder through which the rod passes; and these
grooves may be made to contain metallic, leather, or other rings which
serve as packing behind which steam may be admitted if necessary.
The upper end of the opening may be made tapering to admit the rings.

page_text: Sometimes I make the stuffing box of the greatest diameter at the end
opening into the cylinder, as shewn at m, Figure 2, and I fit into it from
inside a collar n of leather, metal, or other suitable substance of
sufficient flexibility surrounding the piston rod, against which it is
pressed by the steam. The lower or inner end of the collar may be
flanged over and held in its place by an internal ring and screws or bolts.
Or the collar may be flanged both above and below, and may be fitted
in a recess into which steam is admitted behind it.
I prefer however to make the stuffing box of a length somewhat
greater than the stroke of the piston, as shewn at d in Figures 3, 4, 12, 1
15, 16, 17, and 18, and I bore it out to fit the piston rod round which I
make one or more grooves into which metallic or other packing rings y,
y, y, are fitted which work against the inside of the stuffing box.
In some cases I make the piston rod of larger diameter where the
packing rings are fitted so as to become in effect a supplementary piston, 1
which may be used instead of making the piston rod itself of considerable
diameter in order to reduce the effective area of the lower side of the
principal piston, as described in the first part of my Invention.
In order to avoid the necessity for substituting a longer drill when
the full depth of hole has been made which the forward feeding 2
arrangement of the apparatus will allow, I sometimes make the piston rod
hollow, as shewn in Figures 1, 2, 3, and 17, and I arrange the drill bar
inside it, and attach them together by means of a suitable screw, bolt,
or clamp. When the cylinder has been fed forward as far as possible, I
detach the drill bar and then bring back the cylinder to its former 2
position, the drill bar being at the same time withdrawn from the hollow
piston rod, and I then attach them together again and recommence the
operation of drilling.
Where my apparatus is used for the purpose of cutting coal in
collieries, I sometimes use one cylinder, but I prefer to use two or more 30
cylinders made in one casting or attached to the same frame, and
carrying drills which strike the coal (but to which it is not necessary to
give a circular angular motion). These cylinders are carried upon a
frame supported upon wheels or guides in such a manner that a
horizontal or vertical motion at right angles to the drills and parallel to 35
the face of the coal can be given to it. A sufficient number of drills are

page_text: used to make a cut of the depth required, each succeeding drill being of
greater length than the one immediately in advance of it.
The drills may have cutting edges of a width greater than the outer
diameter of the cylinders, so that the latter may themselves be made to
follow the drills into the cut as its depth increases.
The pistons in the cylinders may be actuated by the methods already
described, or by any other of the methods ordinarily used and practised.
Having now described my said Invention and the manner in which it
is to be performed, I claim, the arrangement of cylinders, pistons, and
valves and substitutes for stuffing boxes in reciprocating engines,
substantially as described and shewn in the Drawings.
Also the construction and arrangement of apparatus for giving the
pistons of such engines, a circular angular motion without shock,
substantially as and for the purposes described and shewn in the
Drawings.
Also the combination of such reciprocating engines with the methods
of clamping the cylinder at different angles, substantially as described
and shewn in the Drawings.
Also the method of gradually advancing the cylinders of boring
engines, substantially as described and shewn in the Drawings.
Also the hollow piston rod containing the drill, so that the latter can
be drawn out as required, substantially as described and shewn in tho
Drawings.
Also the arrangement of two or more cylinders, pistons, and cutting
tools for the purpose of cutting coal, substantially as described.
Also the general arrangement and construction of the machines or
apparatus, substantially as described and shewn in the Drawings.
In witness whereof, I, the said Edmund Edwards, have hereunto
set my hand and seal, this Thirteenth day of August, in the
year
of our Lord One thousand eight hundred and seventy-three.
EDMUND EDWARDS. (L.S.)