Improvements IN RECIPROCATING ENGINES
Year: 1874

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 RECIPROCATING ENGINES
PROVISIONAL SPECIFICATION left by the said Edmund Edwards at the
Office of the Commissioners of Patents, with his Petition, on the
30th September 1874.
I, EDMUND EDWARDS, of 38, Southampton Buildings, Chancery Lane,
5 in the. County of Middlesex, Engineer and Patent Agent, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN RECIPRO-
CATING ENGINES DRIVEN BY STEAM, COMPRESSED AIR, OR OTHER FLUID, AND USED
FOR DRILLING HOLES IN ROCKS, OR FOR OTHER PURPOSES, AND IN SUPPORTS FOR
SUCH ENGINES," to be as follows:-
-
0 This Invention relates to reciprocating engines in which a piston is

page_text: driven backward and forward in a cylinder by the force of steam, com-
pressed air, or other elastic or non-elastic fluid, the movement of the
piston in the cylinder being regulated by a valve set in motion by levers,
cams, projections, or the motive fluid itself, and consists, first, of new
and improved methods of constructing and arranging the valve so as to
be simpler and more effective and durable than in such engines as here-
tofore constructed and used.
My improvements are especially applicable to engines used for drilling
holes in rock or other hard substances, but they may also be applied to
steam hammers and other arrangements in which it is required that a
piston shall have a reciprocating movement backward and forward in a
cylinder. I take a piston of greater length than usual, and only fitting
into the cylinder at and near its ends, the intermediate part being of less
diameter. To one end (or both ends) of this piston I form or attach a
piston rod, which passes through a stuffing box (or its equivalent) in the
end or cover of the cylinder. And I form a port or passage at each end
of the cylinder, one end of such port or passage communicating with
the end of the cylinder and the other end forming an opening or port near
the centre of the cylinder, upon which a distributing slide valve of the
usual kind works in the usual way. I make these passages cross each
other, and between the two openings or ports so formed I form a third or
exhaust port, which opens directly into the cylinder in the hollow part
between the two ends of the piston, which hollow part has an exhaust
or discharge pipe leading from it, and is of such length that the exhaust
port is never covered by either end of the piston. I make the face upon
which the distributing valve works form part of the interior of a small
supplementary cylinder parallel to the principal cylinder, or in any other
convenient position; and I make the distributing valve in the form of
a slide valve of the kind ordinarily used and constructed, but having a
curved face to fit the interior of the small cylinder; and I make the
valve fit loosely upon a bar which connects together two small pistons
which fit into and work in the small cylinder, the ends of which are
closed. Steam or other driving fluid is admitted through a single
opening from a supply pipe into the smaller cylinder between the two
small pistons. The distance which the smaller pistons, with the dis-
tributing valve, can travel is such that in passing over it they move the
valve from one end of its stroke to the other, and no more. The bar is
made square, or of such shape that the valve cannot turn round upon it,

page_text: and the valve fitting loosely upon the bar is always pressed against the
face without causing undue friction upon the small pistons.
In order to actuate the small pistons, together with the distributing
valve, I make a port or passage at each end of the smaller cylinder, one
end of such ports opening into the ends of the smaller cylinder, and the
other end opening into the larger cylinder at points where they will be
uncovered by the large piston when it is required that the valve should
be reversed and the direction of motion of the large piston changed.
When the port is thus uncovered the steam (or other fluid) which is
driving tlie piston passes through it to the smaller cylinder and drives
the smaller pistons with the valve in the direction in which the principal
piston is moving, and the motion of the latter is accordingly instantly
reversed. Whilst this is taking place the small port at the other end of
the smaller cylinder communicates with the space between the ends of
the larger piston, and consequently with the exhaust passage or pipe.
Instead of the arrangement described the small ports may pass from
the ends of the smaller cylinder into the larger cylinder at the opposite.
ends, whilst the principal steam ports or passages communicate from the
valve face to the same ends of the larger cylinder respectively. The
face upon which the distributing valve works instead of being curved
and forming part of the smaller cylinder may be flat, separate cylinders
being formed for the two smaller pistons to work in.
The steam or other driving fluid may be admitted into the slide valve
through what has been described as the exhaust port, and may be dis-
charged through what, in the arrangement first described, was the inlet
supply pipe and in this arrangement it is not necesary that either the
principal ports or the small passages should cross cach other, but it is
necessary that the steam should be admitted through an independent
passage into the interior of the valve, and not through the space round
the principal piston, which must communicate with the discharge pipe
or with the open air. The slide valve must be held down to the face.
on which it works by a spring or other suitable means, or in this par-.
ticular arrangement a piston valve may be used.

page_text: In order to prevent the small pistons from striking the ends of the
small cylinder I make the rod connecting the smaller pistons pass
through one or both of the covers or ends of the smaller cylinder, with
or without stuffing boxes in the latter, and I arrange one or more
adjustable elastic buffers upon this rod outside the covers, which strike
against suitably arranged stops at the ends of the stroke of the valve,
so that the smaller pistons are prevented from striking the ends of the
smaller cylinder, and so that the valve may be worked by hand if
desired; and I make the rod square, or of such a shape that it cannot
turn round in a corresponding guide through which it passes, and the
slide valve is thus kept in its proper position in its cylinder.
Another arrangement which I sometimes adopt is as follows:-I make
a small opening or space through each of the smaller pistons, by which
a small quantity of the steam or air passes them and through the
passages already described into the space between the ends of the larger
piston. When either end of the larger piston reaches the end of its
stroke (near the centre of the cylinder) it closes the opening of one of
the passages described, and the steam or air accumulates behind the
smaller piston, with which such passage communicates, and immediately
drives the smaller pistons, and with them the valve, to the other end of
the smaller cylinder, the passage communicating with which is still open
to the space between the ends of the larger piston. I use this arrange-
ment together with those first described, and the large piston will then
work, however short its stroke may be. The slide valve may be arranged
in a chamber or steam chest separate from the cylinder which contains
the smaller pistons, and only one of the latter is then used, the ends of the
cylinder on either side of it being connected alternately with the steam
and with the exhaust passage in the way already described. In this
arrangement the slide valve is connected to the piston by a rod passing
through stuffing boxes.
Another part of my Invention consists in constructing and arranging
the supports for engines of the kind described so that they can be used
to work pumps, or to drive machinery, or for other purposes, as may be
required. For this purpose I arrange the inlet and outlet pipes upon
the engine opposite to one another, and in such a position as to form
trunnions, upon which the cylinder is supported in suitable bearings.
I arrange upon one part of the frame which carries these bearings a
crank shaft and crank, to which the piston rod of the engine can be

page_text: connected when desired; and upon another part of the frame I fix a
pump, to the plunger or ram of which the piston rod of the engine can
be connected when desired by moving the cylinder round upon the
trunnions into the proper position. When moved into other positions
the engine may be used as a hammer, or for other various purposes.
.
The supply and discharge pipes, which are connected to the trunnions,
may pass through suitable stuffing boxes, or may consist of sufficiently
flexible pipes. The arrangement described may be used for other forms
of cylinders as well as for that above described:
Where the arrangement first described is used for the purpose of
drilling holes in rock or other hard substance I prefer to use apparatus
for the purpose of feeding the drill forward as the depth of the hole
increases of the kind described in the Specification of Letters Patent
granted to me for improvements in apparatus for drilling holes in rocks
and other hard substances, dated April 7th 1873, and numbered 1280;
but instead of a valve (as therein described) for the purpose of admitting
steam or air behind the small supplementary piston described I prefer
to make the passage (which is described and shewn for the purpose) open
into the principal cylinder immediately above the principal piston when
the latter is in such a position that the drill has just struck the rock.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Edmund Edwards in the Great Seal Patent Office
on the 30th March 1875.
· 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 Thirtieth day of September, in the
year of our Lord One thousand eight hundred and seventy-four, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, 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 exc-

page_text: cutors, 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 RECIPROCATING ENGINES DRIVEN BY STEAM, COMPRESSED AIR, OR OTHER FLUID,
AND USED FOR DRILLING HOLES IN ROCKS, OR FOR OTHER PURPOSES, AND IN SUPPORTS .
FOR SUCH 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 par-
1
ticularly 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 1
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 Drawing (that is to
say):—
•
This Invention relates to reciprocating engines, in which a piston is 2
driven backward and forward in a cylinder by the force of steam, com-
pressed air, or other elastic or non-elastic fluid; and it consists, first, of
new and improved methods of constructing and arranging the valve
which regulates the movement of the piston, so as to be simpler and
more effective and durable than in such engines as heretofore constructed 2
and used.
My improvements are especially applicable to engines used for drilling
holes in rock or other hard substances, but they may also be applied to
steam hammers, and to other arrangements in which a piston has a recipro-
cating movement in a cylinder. I take a piston of greater length than 3
usual, and fitting into the cylinder at or near its ends, the intermediate
part being of less diameter. At one or both ends of this piston I form
or attach a piston rod passing through a stuffing box (or its equivalent)
in the end or cover of the cylinder, and I form a passage or port at each
end of the cylinder, one end of such passage opening into the cylinder, 3
and the other end forming an opening or port near the centre of the
cylinder, upon which a distributing slide valve of the ordinary kind

page_text: works in the usual way. I make these two passages cross each other,
and between the two ports, upon which the slide valve works, I form a
third or exhaust port opening directly into the cylinder, which has an
exhaust or discharge pipe leading from it in any convenient position.
I make the face, upon which the distributing valve works, form part of
the interior of a small supplementary cylinder parallel to the principal
one, or in any other convenient position; and I make the distributing
valve with a curved face fitting the interior of the small cylinder, which
has its ends closed, the valve fitting loosely upon a bar which connects
together two small pistons in the small cylinder. Steam or other driving
fluid is admitted from a supply pipe through a single opening into the
small cylinder. The bar upon which the valve fits is square, or of such
shape that the valve cannot turn round upon it, whilst the valve is itself
pressed against the face without causing undue friction upon the small
pistons.
In order to actuate the small pistons with the valve I make a small
port or passage at each end of the small cylinder, which passages pass
directly into the principal cylinder at points where they will be un-
covered by the large piston when it is required that the valve should be
reversed, and the direction of motion of the large piston changed.
When one of these passages is thus uncovered the steam (or other fluid)
passes through it, and drives the small pistons and valve in the direction
in which the large piston is moving, and the motion of the latter is thus.
reversed. At the same time the passage at the other end of the small
cylinder communicates with the space between the ends of the large
piston, and consequently with the exhaust or discharge pipe.
In order to prevent the small pistons from striking the ends of the
small cylinder, I make the rod connecting the pistons pass through onc
or both of the covers or ends of the smaller cylinder with or without
stuffing boxes in the latter; and I arrange one or more adjustable
elastic buffers upon this rod outside the covers, which strike against
suitably arranged stops at the ends of the stroke of the valve, so that
the small pistons are prevented from striking the ends of their cylinder,
and so that the valve can be moved by hand if required.
In the accompanying Drawing Figure 1 is a longitudinal section;
and Figure 2, a cross section; and Figure 3 a plan of this arrangement

page_text: applied to rock drilling apparatus; Figure 4 is an end view partly in
section; and Figure 5, a back end view.
a is the principal cylinder; and b, b', the ends of the large piston, the
part c between them being of less diameter; d is a piston rod attached
to the piston; e, e¹, are passages opening into the cylinder a, their other
ends after crossing each other forming ports opening into the small
cylinder f, in which the curved slide valve g works; is an exhaust
port between the other two, and opening directly into the cylinder a,
from which the exhaust steam is discharged at i. The slide valve g
fits loosely upon the square bar k, which connects together the two
small pistons 1, 1, which are shewn, having a rod or spindle passing
through a stuffing box o in one end of the cylinder f. The pas-
sages m, m³, communicate directly from the small to the large cylinder,
as shewn. is the supply pipe leading directly into the cylinder f
between the pistons 1, 1.
The action of the apparatus is as follows:-The piston and valve
being in the position shewn the steam passes through the passage e and
drives back the piston b, the steam at the other end of the cylinder a
passing through the passage e', the valve g, and the passage h into the
space between the pistons and ', whence it escapes through the dis-
charge pipe i. When the piston b has travelled sufficiently far to uncover
the passage m steam passes through the latter into the small cylinder f
and drives the pistons 1, 1, and valve g to the other end of their stroke,
and thus reverses the movement of the large piston until its end b'
returns far enough to uncover the passage m², through which the steam
passes, and drives the pistons 1, 1, and valve g back into the position
shewn in the Drawing, and so on continuously as long as steam or other
driving fluid is supplied through the pipe n.
Instead of the arrangement described I sometimes use a modification
in which the ordinary slide valve, loose upon the bar between the pistons
7, 1, remains the same, but the passages e, e¹, do not cross each other, and
the small passages m, m³, cross each other, the operation of the apparatus
being otherwise the same. The valve g may in either arrangement work
upon a flat instead of a curved face, and separate cylinders may be used
for the two smaller pistons 1, 1, to work in.
:
Figure 6 is a horizontal section through the small cylinder f. The
steam or other driving fluid may be admitted into the slide valve through

page_text: the exhaust port h, and may be discharged through the pipe n, and in
this arrangement it is not necessary that either the principal passages
e, e', or the smaller ones m, m', should cross each other, but it is necessary
that the steam should be admitted through an independent passage into
the port h, which must not communicate with the space between the
pistons and b¹, which must still be open to the discharge pipe or open
air, and serves as the outlet for the steam in the small passages m, m',
alternately. The slide valve g must be held down to the face on which
it works by a spring or other suitable means, or in this particular
arrangement a piston valve may be used.
Sometimes I make a series of holes from the small passages m, m³,
into the cylinder a, either of which holes may be opened or closed as
desired so as to vary the length of stroke of the pistons b, b'.
Figure 1 shews the bar which drives the slide valve g prolonged
through a stuffing box o, and working through a guide p, adjustable
rings or washers being fitted upon the bar to regulate the travel of the
valve. The guide p is made of such a shape as to prevent the bar from
turning round, as shewn in Figure 5.
Another arrangement which I sometimes use to regulate the move-
ment of the small pistons 1, 1, and the valve g is the following:-
-I
make a small opening through or round the pistons 1, 2, through which
the steam passes, and thence through the passages m, m³, to the exhaust
pipe. When one of the pistons 6 or b₁ has travelled far enough to cover
the opening m or m¹ the steam accumulates outside the piston / or / and
forces it together with the valve to the other end of the small cylinder f.
In this arrangement the ends of the passages m, m³, should pass into the
cylinder a near the centre of the length of the latter in order to prevent
the pistons b, b, from having too short a stroke. The slide valve may
be contained in a chamber or steam chest separate from the cylinder
which contains the smaller pistons 1, 1, and only one of the latter is
then used, the ends of the cylinder on either side of it being connected
alternately with the steam and with the exhaust passage in the way
already described, and the piston being connected with the valve by a
rod passing through stuffing boxes.
Where my Invention is used for the purpose of drilling holes in
rocks or other hard substances the drill is attached to the end of the
piston rod d, and it is desirable that between each stroke the pistons b, b¹,.

page_text: should turn partly rounⱭ. This may be elected in the way described
in the Specification of Letters Patent granted to me February 13th
1873, No. 541, or in any other convenient manner.
Where the cylinder and drill, constructed as above described, are to
be fed forward as the depth of the hole which is being drilled increases
by self-acting apparatus, I prefer to use the methods described and
shewn in the Specification and Drawing of Letters Patent granted
to me dated April 7th 1873, No. 1280. This arrangement, modified and
improved to suit my present Invention, is shewn in Figures 1, 2, 3, 4,
and 5, in which A is a small cylinder formed upon or attached to the
cylinder cover B, and having a piston and rod carrying a ratchet or
pall C, which actuates the wheel D upon the feeding screw t. One end
of the cylinder A is connected by the passage 3 with an opening into
the principal cylinder a near its further end, and the other end of the
cylinder A is connected by the passage 4 with an opening into the
cylinder a at a point where it is uncovered by the piston 6 when
the drill bas penetrated sufficiently into the rock (or other substance)
for the cylinder to be fed forward. If the drill does not penetrate
sufficiently the passage 4 will not be uncovered and the piston and
ratchet will not make their return stroke in the cylinder A, and conse-
quently after the next stroke of the drill the cylinder a is not fed
forward in the cradle or carriage v.
The next part of my Invention relates to improvements in constructing
and arranging the supports used for carrying engines of the kind above
described, or of analogous kinds, so that they may be used to drive
machinery, or to actuate hammers, or pumps, or other suitable apparatus
as may be desired. For this purpose I arrange the inlet and outlet pipes
upon the cylinder opposite to one another, and in such positions as to
form trunnions upon which the cylinder is supported in suitable
bearings. Upon one part of the frame which carries these bearings a
crank shaft and crank are arranged, revolving in suitable bearings, so
that the piston rod of the engine can be connected to the crank when
desired, and used for driving any kind of hoisting or other machinery.
At another part of the frame a pump may be fixed, to the plunger or
ram of which the piston rod may be connected when disengaged from
the crank, the cylinder being turned round upon its trunnions into the
proper position for the purpose. In another position the piston rod may

page_text: be connected to a hammer, the cylinder being fixed in its proper position
by keys or bolts.
When moved into other positions the engine may be used for other
purposes as desired.
The supply and exhaust pipes from the cylinder may be connected to
the trunnions by suitable stuffing boxes, or by lengths of sufficiently
flexible pipe. This part of my Invention may be applied to other forms
of cylinders as well as those above described. Figure 7 is in illustration
of this arrangement, shewing an elevation of one form of arrangement
in which the cylinder may be applied to turning a shaft and fly wheel,
driving a pump, or working a hammer, as may be desired. a is the
cylinder shewn, of a kind similar to those above described. b is the
framework, which may be made of any suitable form, and supports the
cylinder a in the bearings c. At d are arranged in the frame bearings for
a crank shaft g, to the crank pin of which the piston rod working in the
cylinder a can be connected. At e is shewn a pump, supported by the
framework b, and arranged so that the piston rod of the cylinder a can
be connected to it when required. In the Drawing the cylinder a is
shewn fixed in a vertical position by the fastening i, and having its
piston rod attached to a hammer head f. When it is desired to drive
the crank shaft g and fly wheel h, the piston rod is detached from the
hammer head f, and is connected to the crank pin, the cylinder a
being turned round in the bearings c which support it, and on which it
oscillates whilst driving the crank shaft, which it will do in either
direction.
Having now described my Invention, and the manner in which it is to
be performed, I claim,-
The methods of actuating the pistons of reciprocating engines by
means of an ordinary slide valve fitting loose upon a bar connecting
two pistons, between which the driving fluid is admitted through a single
opening, the pistons being actuated by the alternate opening and closing
by the principal piston of passages arranged for the purpose, substantially
as described and shewn in the Drawing.
Also the method of regulating the stroke of the slide valve, and of
working it by hand when required, substantially as described and shewn
in the Drawing.

page_text: Also the method of regulating the supply of the driving fluid to the
apparatus for feeding forward the feed screw when used for drilling holes,
so that no additional valve is required, substantially as described and
shewn in the Drawing.
Also the methods of arranging frames to support engines actuated by
steam, compressed air, or other elastic or non-elastic driving fluid, so
that such engines may be used for different purposes at different times,
substantially as described and shewn in the Drawing.
In witness whereof, I, the said Edmund Edwards, have hereunto
set my hand and seal, this Twenty-seventh day of March, in
the year of our Lord One thousand eight hundred and seventy-
five.
EDMUND EDWARDS. (L.S.).