IMPROVEMENTS IN APPARATUS FOR DRILLING HOLES IN ROCKS OR OTHER HARD SUBSTANCES, AND IN MACHINERY FOR COMPRESSING AIR FOR THE PURPOSE OF ACTUATING SUCH APPARATUS, PARTS OF WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO OTHER PURPOSES."
Year: 1877

page_text: «
LETTERS PATENT to Edmund Edwards, of 40, 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
OR OTHER HARD SUBSTANCES, AND IN MACHINERY FOR COMPRESSING AIR
FOR THE PURPOSE OF ACTUATING SUCH APPARATUS, PARTS OF WHICH
IMPROVEMENTS ARE ALSO APPLICABLE TO OTHER PURPOSES."
PROVISIONAL SPECIFICATION left by the said Edmund Edwards at the
Office of the Commissioners of Patents on the 20th July 1877.
66
EDMUND EDWARDS, of 40, Southampton Buildings, Chancery Lane, in the County
of Middlesex, Engineer and Patent Agent. IMPROVEMENTS IN APPARATUS FOR
DRILLING HOLES IN ROCKS OR OTHER HARD SUBSTANCES, AND IN MACHINERY FOR
COMPRESSING AIR FOR THE PURPOSE OF ACTUATING SUCH APPARATUS, PARTS OF
WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO OTHER PURPOSES."
The first part of my Invention consists of improved methods of constructing and
arranging the mechanism by which the piston is made to reciprocate backward and
forward in the cylinder of rock-boring machines. For this purpose I take a cylinder
of suitable length and diameter, and provided with ends or covers in the usual way.
In this cylinder is fitted a piston, which can work freely backward and forward
from end to end, and a piston rod is formed upon or attached to one or both ends of
the piston and passes through stuffing boxes in the cylinder cover. To the outer
end of the piston rod a drill is attached in the usual way. The piston is made of
considerable length, and its centre is turned of less diameter so as to form an
annular groove, the edges of which taper gradually down from the full diameter of
the piston to that of the annular groove. Upon one side of and parallel to the
cylinder I form or attach a smaller supplementary cylinder, and upon one side of
this smaller cylinder I form three ports or openings, the two outer ones communi-
cating through a suitable passage each with one end of the main cylinder, and the
centre one communicating with the opening through which the compressed air or
Price 6d 1

page_text: other elastic fluid used to operate the piston is discharged. Upon the inside of the
smaller cylinder and against the ports in its side is fitted and works a slide valve of
the usual construction, by which the motor fluid can be admitted to either end of
the principal cylinder alternately. This slide valve is driven by a longitudinal bar
fitted against its back and having at each end an opening or joint fitting the outer
ends of two bent or bell-crank levers, the inner ends of which project into the
principal cylinder. These levers pass through a longitudinal slot communicating
between the two cylinders, and are pivotted upon transverse pins passing across the
same slot, and the two inner ends of the levers are turned towards each other (or in
opposite directions), and each end where it enters the principal cylinder is rounded,
so that when the valve is at one end of its stroke the rounded end of the lever at
the same end is lifted out of the large cylinder into the slot between the two
cylinders, whilst the rounded end of the other lever is depressed a sufficient distance
into the principal cylinder. When the valve is at the other end of its stroke the
relative position of the inner ends of the two levers is reversed.
The size of the annular groove, already described, round the piston is so propor-
tioned that when the piston is at one end of its stroke the rounded inner end of the
bell-crank lever at the opposite end has just been raised out of the annular groove
by the tapered edge of the latter, thus reversing the valve, and, by the same move-
ment, depressing the rounded inner end of the other lever into the annular groove.
When the piston reaches the other end of its stroke the contrary action takes place,
and the position of the valve is again reversed and the action of the apparatus
continues as long as compressed air or other motor fluid is supplied to the interior
of the smaller cylinder through a suitable pipe.
The slide valve may be arranged to work upon a flat face instead of upon the
inside of a supplementary cylinder, in which case I form a back and top to the
chamber in which the valve works out of a separate piece bolted or screwed to its
place.
The novel method of actuating the piston, as described, may be applied to cylinders
used for other purposes as well as to drilling holes, as, for instance, to working
hammers, pumps, or machinery of different kinds.
Another part of my Invention consists of improved methods of constructing and
arranging apparatus for compressing air to be used for actuating apparatus of the
kind just described, or other apparatus used for similar purposes, by which improved
methods such machinery is made more simple, durable, and effective than has here-
tofore been the case. I take two compressing cylinders arranged side by side and
open at their upper ends. Each cylinder is provided with a piston or plunger which
fits as nearly air-tight as possible, but can work freely from end to end of the
cylinder. These pistons may be fitted, if desired, with packing rings or packing in
the usual way. The cylinders are fixed vertically upon a suitable bed plate or
foundation, and I arrange round them a cistern containing cold water, the level of
which is kept, preferably, slightly above the upper edges of the cylinders, so that
when the pistons are made to descend water enters the cylinders above them during
the first part of their stroke. Or water may be supplied above each piston through
a small supply pipe, the level of the water in the cistern being in this case slightly
below the upper edges of the cylinders. Upon the same bed plate or foundation I
arrange frames, preferably of iron, which carry in their upper parts bearings in
which revolves a strong shaft having fitted upon it two excentrics fitted with straps
and connecting rods, the lower ends of which are jointed to the piston in the
cylinder. Or they may be jointed to rods attached to the pistons and working
through guides. I arrange the connecting rods so that their length can be adjusted
for the purpose of bringing the pistons to the bottom of the cylinders at each stroke,
and thus reducing the waste of air or other fluid which is being compressed. Upon
the revolving shaft I fix one or more heavy fly wheels and a driving pulley or wheel
by which the shaft can be driven by any convenient power; or sometimes I fix upon
it a crank which is driven by a steam cylinder (either horizontal or vertical) in the
usual way.

page_text: The two excentrics are arranged opposite to one another, so that when one piston
is at the top the other is at the bottom of its stroke. Between the two cylinders,
or adjoining them at their lower ends, I arrange a four-way cock, fitted with a plug
and having four openings, two of which (opposite to each other) open into the lower
ends of the two cylinders respectively, whilst of the other two one is connected to
a pipe through which the air or other elastic fluid which is to be compressed is
supplied, whilst the other is connected to a pipe through which the compressed air
or other fluid is delivered, and I arrange as close as possible to this last opening a
valve opening outwards, but kept in its seat by a spring in order to prevent the
return of the air or other fluid so delivered. I connect the plug of this four-way
cock to the revolving driving shaft, already described, by means of bevel toothed
wheels and shafts in such a manner that it is made to revolve continuously, but only
makes one revolution whilst the driving shaft makes two. I prefer to make the
parts of the revolving plug which cover the openings in the four-way cock somewhat
wider than the said openings so as to reduce the liability to leakage past the former,
and I arrange the position of the plug so that when either piston is at the bottom
of its stroke the opening into the cylinder from the fourway-cock is just closed.
The action of the apparatus is as follows:-The driving shaft being made to
revolve when one piston is at the bottom of its stroke, as described, the plug in the
cock revolves at the same time, and after the piston has risen for a short distance
the plug opens a communication to the inlet pipe through which air is admitted
into the cylinders. When the piston arrives at the top of its stroke the inlet
opening is shut, and when the piston has descended for a short distance the passage
into the delivery pipe is open and the air is compressed until its pressure is sufficient
to open the valve, already described, through which it is forced into delivery pipes,
or a reservoir, until the piston has reached the bottom of its stroke, the revolving
plug having then made one half of a complete revolution. Precisely the same series
of operations takes place in the other cylinders.
The object of the delivery valve described is to prevent the full pressure of the air
from the reservoir or delivery pipes from coming upon the pistons during their
descent until the air has been compressed to a pressure greater and therefore
sufficient to open the valve.
By the novel arrangements described, the apparatus can be driven at a very great
speed, there being no inlet and outlet valves of the usual kind, and the cylinders and
pistons are kept cool in the way described. A small quantity of water may be
admitted into the inlet pipe with the air if required.
Instead of the fourway-cock and revolving plug, as described, which I prefer, I
sometimes use an ordinary slide valve working upon a face having three ports, and
driven by an excentric upon the driving shaft above, the air being admitted through
the centre port into the back of the slide valve and being discharged into a pipe
communicating with the chamber in which the slide valve works, this pipe being
provided with a delivery valve similar to that already described. Each of the end
ports in the slide valve face communicates by as short a passage as possible with
the lower end of one of the pump cylinders already described. Or cylindrical plug
valves worked by an excentric and having suitable openings may be used.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edmund Edwards in the Great Seal Patent Office on the 19th
January 1878.
EDMUND EDWARDS, of 40, Southampton Buildings, Chancery Lane, in the County
of Middlesex, Engineer and Patent Agent. "IMPROVEMENTS IN APPARATUS FOR
DRILLING HOLES IN ROCKS OR OTHER HARD SUBSTANCES, AND IN MACHINERY FOR
COMPRESSING AIR FOR THE PURPOSE OF ACTUATING SUCH APPARATUS, PARTS OF
WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO OTHER PURPOSES."
The first part of my Invention relates to the mechanism by which the piston is
made to reciprocate backward and forward in a cylinder by the pressure of steam,
compressed air, or other elastic fluid, for the purpose of actuating drills for boring
holes in rock or other hard substances. It consists of improved methods of con-
structing, arranging, and actuating the valves by which such reciprocation is effected.
I take a cylinder of suitable length and diameter, and provided with ends or covers
in the usual way.
In this cylinder is fitted a piston which can work freely back-
ward and forward from end to end, and a piston rod is formed upon or attached to
one or both ends of the piston, and passes through stuffing boxes or their equivalents
in the covers. To the outer end of the piston rod a drill is attached in the usual
way. The piston is made of considerable length, and its centre is of less diameter
than its ends, so as to form an annular groove or recess, the edges of which taper
gradually down from the full diameter of the piston to that of the groove. Upon
one side of the cylinder, and parallel to it, I make or attach a smaller supplementary
cylinder, and upon one side of this smaller cylinder I form three ports or openings,
the two outer ones communicating through a suitable passage, each with one end of
the main cylinder, and the centre one communicating with the opening through
which the steam, compressed air, or other driving fluid is discharged. Upon the
inside of the smaller cylinder, and against the ports in its side, is fitted and works
a slide valve of the usual construction, by which the motor fluid can be admitted to
either end of the principal cylinder alternately. This slide valve is driven by a
longitudinal bar fitted against its back, and having at or near each end an opening
or joint fitting the outer ends of two bent or bell-crank levers, the inner ends of
which project into the principal cylinder. These levers pass through a longitudinal
slot or opening communicating between the two cylinders, and they are pivotted
upon transverse pins passing across the same slot. The two inner ends of the levers
are turned toward each other (or in opposite directions), and each end where it
enters the principal cylinder is rounded, so that when the valve is at one end of its
stroke the rounded end of the lever at the same end is lifted out of the large
cylinder into the slot between the two cylinders, whilst the rounded end of the
other lever is depressed a sufficient distance into the principal cylinder. When the
valve is at the other end of its stroke the relative positions of the two levers is the
reverse of that just described.
The size of the annular groove round the piston is so proportioned that when
the piston is at one end of its stroke the rounded inner end of the lever at the
opposite end has just been raised out of the groove by the inclined or tapered edge
of the latter, thus reversing the valve, and by the same movement depressing into
the groove the rounded inner end of the other lever. When the piston reaches the
other end of its stroke the contrary action takes place, and the position of the valve
is again reversed, and the action of the apparatus continues as long as compressed
air or other motor fluid is supplied to the interior of the smaller cylinder through a
suitable pipe.
In the accompanying Drawings Figures 1 and 2 are in illustration of this part of
my Invention, Figure 1 being a longitudinal section and Figure 2 a transverse
section of the apparatus.
a is the principal cylinder; bis the piston; c, the piston rod; and e is the annular
groove round the piston; f is the smaller cylinder, having three ports g, h, i, in its

page_text: side, g communicating with one end of the cylinder a through the passage g', h com-
municating with the other end of a through the passage h', and i communicating
with a discharge pipe or opening; k is the slide valve, driven by the bar l, which is
actuated by the bent levers m, m', pivotted upon the pins n, n', and passing through
the slot o. The bar is shewn working in guides in the ends of the smaller
cylinder f. The slide valve may be arranged to work upon a flat face instead of
upon the inside of a supplementary cylinder, in which case I form a back and top
to the chamber in which the valve works of a separate piece, bolted or screwed to
its place.
The novel method of actuating the piston and valve, as described, may be applied
to cylinders used for other purposes as well as to drilling holes, as for instance, to
working hammers, pumps, or machinery.
I claim, the combination of a piston having an annular groove with inclined
edges with a slide valve, actuated by two bent levers having their inner ends pro-
jecting alternately through a slot in the cylinder into the groove in the piston, their
outer ends being jointed to a slide valve, or to a bar carrying a slide valve, sub-
stantially as and for the purpose described, and shewn in the Drawing.
Another part of my Invention relates to machinery or apparatus for compressing
air to be used for actuating apparatus of the kind just described, or other apparatus
used for similar or other purposes, and consists of improved methods of constructing
and arranging the several parts of such machinery or apparatus, by which improved
methods it is made more simple, durable, and effective than has heretofore been the
case. I take two compressing cylinders, arranged side by side, and open at their upper
ends. Each cylinder is fitted with a piston or plunger, which fits as nearly air
tight as possible, but can work freely from end to end of the cylinder. These pistons
may be fitted, if desired, with packing rings or packing in the usual way. The
cylinders are fitted vertically upon a suitable bed plate or foundation, and I arrange
round them a cistern containing cold water, the level of which is kept preferably at
such a height that when the piston is at the bottom of its stroke the water enters
it or the cylinder above it. Or water may be supplied above each piston through a
. small supply pipe, the level of the water in this case being slightly below the upper
edges of the cylinders. Upon the same bed plate or foundation I arrange frames of
iron or other suitable material, carrying in their upper parts bearings, in which
revolves a strong shaft having fitted upon it two excentrics with straps and con-
necting rods, the lower ends of which are jointed to the pistons already described.
Or they may be jointed to rods attached to the pistons and working through
guides. I arrange the connecting rods so that their length can be adjusted for the
purpose of bringing the pistons as nearly as possible to the bottom of the cylinders
at each stroke, and thus reducing the waste of air or other fluid which is being
compressed. Upon the revolving shaft I fix one or more heavy fly wheels and a
driving wheel or pulley, by which the shaft can be driven by any convenient power,
or sometimes I fix upon it a crank which is driven by a steam cylinder (either
vertical or horizontal) in the usual way.
The two excentrics are arranged in positions opposite to each other, so that
when one piston is at the top the other is at the bottom of its stroke. Between
the two cylinders, or adjoining them at their lower ends, I arrange a four-
way cock fitted with a plug and having four openings, two of which (opposite
to each other) open into the lower ends of the two cylinders respectively,
whilst of the other two one is connected to a pipe through which the air or
other fluid which is to be compressed is supplied, and the other is connected
to a pipe through which the compressed air or other fluid is delivered, and I prefer
to arrange as close as possible to this last described opening a valve opening out-
ward, but kept in its seat by a spring, for the purpose hereinafter described. I
connect the plug of the four-way cock, so arranged, to the revolving driving shaft
by means of toothed wheels and shafts in such a manner that it is made to revolve
continuously, but only makes one revolution whilst the driving shaft makes two.
I prefer to make the parts of the revolving plug which cover the openings in the

page_text: four-way cock, somewhat wider than the said openings so as to reduce the liability
to leakage past the former, and I arrange the position of the plug so that when one
of the pistons is at the bottom of its stroke the opening into the cylinder from the
four-way cock into the delivery pipe is just closed.
In the accompanying Drawings Figure 3 is a longitudinal section, and Figure 4 a
sectional plan of a machine constructed according to this part of my Invention.
is the foundation plate; b, 61, frames having bearings c, c¹, in which the shaft d
revolves, carrying a fly wheel; e, e¹, are two air compressing cylinders; f is a
cistern of cold water, surrounding the cylinders; g, g¹, are the pistons, worked by
connecting rods h, h¹, actuated by excentrics i, i, upon the shaft (shewn in front
view in Figure 5); k is the four-way cock, having the plug and four openings
x, x1, x2, and x³. In the outlet passage ³ is arranged the check valve n (shewn
in section in Figure 6). The plug is connected to the driving shaft
wheels and shaft m, so as to revolve at half the speed of the shaft d. In Figure 4
the plug is shewn in four different positions.
l
by the
The action of the apparatus is as follows:-The driving shaft & being made
to revolve, one piston being at the bottom of its stroke, the plug also
revolves, and when the piston has risen for a short distance opens a communi-
cation to the inlet pipe and opening a, through which air is drawn into the
cylinder from x². When the piston reaches the top of its stroke the inlet'
opening 2 closes, and after the piston has descended for a short distance the
outlet passage 23 opens, and the air is compressed until it opens the valve n,
through which it passes into a delivery pipe or a receiver until the moment when
the piston reaches the bottom of its stroke, when the opening x³ closes, the
plug having then made one half of a complete revolution. A similar series of
operations takes place in the other cylinder, the openings 2 and 3 being closed at
the top and bottom of the stroke. The valve prevents the full pressure of the
air in the receiver or delivery pipe from coming under the descending pistons until
they have compressed the air sufficiently to open the valve, but it may be omitted
if desired. The apparatus may be used for exhausting or rarifying instead of com- (
pressing, in which case the valve n is not needed, nor is the water cistern required.
In Figure 7 a modified arrangement of my improved apparatus is shewn in
longitudinal section, a receiver for the compressed air forming part of the apparatus.
a is a strong vertical cylinder (preferably of wrought iron), the lower part of
which forms a receiver, whilst its upper part c forms the water cistern in which
the cylinders e, e¹, are fixed. The shaft d revolves in bearings f, f¹, fixed to the
cistern c.
The remainder of the apparatus is similar to that already described.
o is a delivery pipe from the receiver b. The shaft d may be driven by any
suitable power.
Figure 8 is a vertical section, and Figure 9 an end view of a modified form of
my improved apparatus where great pressure is required. a is a strong foundation
plate (preferably of wrought iron) having bolted or rivetted to it the plates which
form the cistern b. To these plates are bolted or rivetted the bearings c, c¹, in
which the very strong shaft & revolves; this shaft has two cranks e, e', formed upon
it by which (instead of by excentrics) the connecting rods h, h¹, drive the plungers
g, g, which fit the cylinders i, i¹. The four-way cock k is fixed between the
cylinders, and its plug is made to revolve by a tangent toothed wheel m fixed
upon its axis and driven by the counter shaft n, which also drives the crank shaft d
by means of the spur wheels o, o¹. The number of teeth upon the different wheels
and endless screw are so proportioned that the plug & revolves at one-half the speed
of the shaft d, which is driven by any convenient power.
I prefer to arrange a check or relief delivery valve (not shewn in the Drawing)
in the same way as in the arrangements before described.
Instead of delivering the compressed air into a receiver, whence it is withdrawn
and used, a second set of apparatus (of properly proportioned size) similar to that
described may take it and still further compress it, and so on as often as may be
desired.

page_text: A small quantity of water may be admitted into the inlet pipe with the air if
desired, and a double-acting cylinder may be used having at each end a cock with
a revolving plug. Or, instead of a four-way cock in the arrangements described, an
ordinary slide valve may be used working upon a face having three ports, and
driven by an excentric upon the driving shaft above, the air being admitted through
the centre port into the hollow of the slide valve, and being discharged into the
chamber in which the slide valve works, and thence into a pipe provided with a
relief delivery valve similar to those already described.
Each of the end ports in the slide valve face communicates by as short a passage
as possible with the lower end of one of the pump cylinders already described.
Or cylindrical plug valves worked by excentrics and having suitable openings may
be used.
By the use of my improved apparatus, as described and shewn, the pumps may
be driven at a very great speed, there being no inlet and outlet valves of the usual
kind.
Having now described my Invention, and the manner in which it is to be per-
formed, I claim,-'
The combination of the cylinders and pistons, or cylinder and piston, with the
four-way cock having a plug made to revolve continuously, substantially as and for
the purpose described, and shewn in the Drawing.
Also the combination of two single-acting cylinders and pistons standing in a
cistern of cold water, and actuated by two excentrics or cranks upon a driving
shaft with a four-way cock having a revolving plug, substantially as described, and
shewn in the Drawing.
Also the combination of the four-way cock, as described, with the delivery valve,
substantially as and for the purpose described, and shewn in the Drawing.
Also the general arrangement of apparatus for compressing or exhausting elastic
fluids, substantially as described, and shewn in the Drawing.
In witness whereof, I, the said Edmund Edwards, have hereunto set my
hand and seal, this Eighteenth day of January, in the year of our Lord One
thousand eight hundred and seventy-eight.
FDMUND EDWARDS
1
EDMUND EDWARDS
(L.S.)