IMPROVEMENTS IN MACHINERY OR APPARATUS FOR TUNNELLING OR FORMING GALLERIES IN MINES, QUARRIES, AND OTHER PLACES
Year: 1870

page_text: LETTERS PATENT to Thomas Frederick Henley, of Pimlico, in the
County of Middlesex, for the Invention of "IMPROVEMENTS IN
MACHINERY OR APPARATUS FOR TUNNELLING OR FORMING GALLERIES IN MINES,
QUARRIES, AND OTHER PLACES."
Sealed the 13th January 1871, and dated the 26th August 1870.
PROVISIONAL SPECIFICATION left by the said Thomas Frederick
Henley at the Office of the Commissioners of Patents, with his
Petition, on the 26th August 1870.
I, THOMAS FREDERICK HENLEY, of Pimlico, in the County of
Middlesex, do hereby declare the nature of the said Invention for
***IMPROVEMENTS IN MACHINERY OR APPARATUS FOR TUNNELLING OR FORMING
GALLERIES IN MINES, QUARRIES, AND OTHER PLACES," to be as follows:-
The object of my Invention is to excavate tunnels, galleries, or passages
in mines, quarries, or other situations by means of a machine or appa-
ratus which may be driven by steam, compressed air, atmospheric
pressure, or other motive power.

page_text: My Invention consists of a tool holder or head adapted for receiving
chisels or tools suitable for cutting rock. This tool holder is combined
with an arm or shaft; the two together for the purposes of this
description are called the ram head and ram shaft, or collectively the
ram. This ram is mounted by suitable connections on a main frame
or base plate, which is fitted with wheels or skids and guide rollers for
the purpose of advancing or withdrawing the machine, as may be
required. The said ram is made to receive a fore and aft movement of
percussion from any suitable motor simultaneously with a horizontal
motion to the right or left, and vice versa, by means of mechanical
arrangements which may be described as follows :—
At the front end of the machine, and as nearly as possible to the ram
head, I place a ball or spherical body underneath the ram shaft, which
ball is borne upon a plane surface provided for the purpose. Upon this
ball the ram is free to move horizontally in any direction to and fro and
laterally. The to-and-fro motion of percussion is given by the power as
aforesaid, the lateral travel is provided for, and the intervals or spaces
between the blows of the ram and its chisels are regulated by means of a
ratchet movement or equivalent contrivance operating during the back
stroke of the ram. The ram moves in the arc of a circle on a main
centre point placed at the back end of the ram arm or shaft. The ram
head or tool holder is of sufficient breadth to hold one or several rows of
chisels placed vertically, and the breadth of the gallery depends on the
lateral motion given by the ratchet or other arrangement as aforesaid.
The ram head is the same height as the tunnel or gallery to be excavated.
By these dispositions abundant room is provided for a man to get at the
front of the machine for changing chisels or otherwise. The central
chisels of the ram head are arranged in a lower line than those at the
sides in such manner that during the operation of the machine a channel
is cut of greater depth in the middle of the tunnel than at the sides. The
portion left at the side walls serves to carry the bearing wheels or skids
of the base plate, and the deeper portion forms a channel in which an
endless chain of scrapers is made to move slowly by suitable wheelwork,
so as to bring out to the rear the debris of rock produced by the action
of the machine.
This machine is calculated to dispense with the use of explosives in
rock tunnelling; it is continuous in its action, or only requiring to be
stopped for the purpose of changing the chisels; it removes its own

page_text: debris as produced, and possesses the advantage of forming a rectangular
gallery as distinct from a circular opening, thus admitting of the direct
employment of a steam generator at the tunnel face. In its general
character it represents the application of thic principle of the steam
hammer to rock tunnelling.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Frederick Henley in the Great Seal Patent
Office on the 25th February 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
FREDERICK HENLEY, of Pimlico, in the County of Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of August, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Thomas Frederick Henley, Her special licence
that I, the said Thomas Frederick Henley, my executors, administrators,
and assigns, or such others as I, the said Thomas Frederick Henley, 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 MACHINERY OR APPARATUS FOR TUNNELLING OR FORMING GALLERIES IN MINES,
QUARRIES, AND OTHER PLACES," upon the condition (amongst others) that I,.
the said Thomas Frederick Henley, 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 Thomas Frederick Henley, 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

page_text: and by the following statement thereof, reference. being had to the
Drawings hereunto annexed, that is to say::-
The object of my Invention is to excavate tumels, galleries, or
passages in mines, quarries, or other situations by means of a machine or
apparatus which may be driven by steam, compressed air, atmospheric
pressure, or other motive power.
My Invention consists of a tool holder or head adapted for receiving
chisels or tools suitable for cutting rock. This tool holder is combined
with an arm or shaft; the two together for the purposes of this
description are called the ram head and ram shaft, or collectively the
ram. This ram is mounted by suitable connections on a main frame or
base plate, which is fitted with wheels or skids and guide rollers for the
purpose of advancing or withdrawing the machine as may be required.
The said ram is made to receive a fore and aft movement of percussion
from any suitable motor simultaneously with a horizontal motion to the
right or left, and vice versa, by means of mechanical arrangements
which may be described as follows:-
At the front end of the machine, and as nearly as possible to the ram
head, I place a ball, or balls, or spherical bodies underneath the ram
shaft, which ball or balls are borne upon a plain surface provided for the.
purpose. Upon these balls the ram is free to move horizontally in any
direction to and fro and laterally. The to-and-fro motion of percussion
is given by the power as aforesaid, the lateral travel is provided for, and
the intervals or spaces between the blows of the ram and its chisels are
regulated by means of a ratchet movement or equivalent contrivance
The ram moves in the are
operating during the back stroke of the ram.
of a circle on a main centre point placed at the back end of the ram, arm,
or shaft.
The ram head or tool holder is of sufficient breadth to hold
one or several rows of chisels placed vertically, and the breadth of the
gallery depends on the lateral motion given by the ratchet or other
arrangement as aforesaid. The ram head is the same height as the
tunnel or gallery to be excavated. By these dispositions abundant
room is provided for a man to get at the front of the machine for
changing chisels or otherwise. The chisels may be of any suitable
form; their cutting faces may be placed vertically, horizontally, or
diagonally, or shaped into points diamondwise, all the dispositions to be
decided upon according to circumstances and the nature of the rock or
material to be operated upon. The central chisels of the ram head are

page_text: arranged in a lower line than those at the sides, in such manner that
during the operation of the machine a channel is cut of greater depth in
the middle of the tunnel thair at the sides. The portion left at the
side wall serves to carry the bearing wheels or skids of the base plate,
and the deeper portion forming a channel in which an endless chain of
scrapers is made to move slowly by suitable wheelwork so as to bring
out to the rear the debris of rock produced by the action of the machine.
Scrapers are likewise provided at the lower part of the ram for
facilitating the withdrawal of the debris from the rock face..
This machine is calculated to dispense with the use of explosives in
rock tunnelling; it is continuous in its action, or only requiring to be
stopped for the purpose of changing. the chisels;. it removes its own
debris as produced, and possesses the advantage of. forming a. rectangular
gallery as distinct from a circular opening, thus facilitating the direct
employment of a steam generator at the tunnel face.;. in. its general
character it represents the application of the principle of the steam
hammer to rock tunnelling.
The particular machine shown in the annexed Drawings is intended
for cutting a gallery 4 ft. wide by 5 ft. high, this being a convenient size
for many purposes; it consists of a massive cast-iron bed plate mounted
on six wheels, and carrying near one end the steam or compressed air
cylinder, and at the other the traversing gear by which the head is made
to traverse to and fro laterally. The head is shown as made in one piece
with a shaft, and when this system of construction. is adopted it is.
intended to make it of Mac Haffie's malleable cast iron or of mild steel ;.
the shaft may, however, be in some cases made of wrought iron and
bolted or keyed to the head. The head extends the full depth of the
gallery, and is 1 ft. 8 in. broad at the widest part; its shape in plan being
shown in Figure 2. In the face of the head are formed five grooves of a
kind of dovetail section, as shown in the Figure just referred to, the ribs.
on the sides of the grooves forming the dovetail being,.however,, removed
for a depth about 12 in. from the top of the head. The grooves receive
the chisels, which are made in 12. in. lengths, and which are inserted
(the head been drawn back from the face of the rock) at the upper part
of the grooves, where the ribs are absent and dropped into their places..
The upper lengths are held in their places by bolts.
Referring to Figure 2 it will be seen that the chisels are each made
with four cutting edges, so that there are altogether twenty rows of

page_text: cutting edges in the width of the head. Each of the outer rows of
chisels stops short 4 in. from the bottom of the head, and thus the latter
is made to cut a gallery having a step or ledge 4 in. high by 4 in. wide
at each of its lower corners. These ledges, which are shown in Figures 3,
4, and 5, serve to support the machine, the wheels on which the latter is
carried travelling on these ledges, and being thus kept clear of the
débris. The chisels may be made of steel or of wrought iron with steel
faces, but for many kinds of rock they will serve perfectly well if made
of a much cheaper material, namely, chilled cast iron; from their
cutting faces being straight they can be very readily ground, and when
they are chilled castings they will require no fitting to the grooves in
the head. The shaft, formed in one piece with the head or keyed to the
latter, is furnished with a spherical end, which abuts-against-a-wrought-
iron cup placed at the bottom of the front trunk of the piston, and
which is held firmly in its place by a suitable gland. This gland is
made in three pieces, namely, two halves of gun metal fitting the sphere,
and an outer ring of wrought iron holding these halves together. The
gland is tightened by bolts furnished with countersunk collars, so that
they serve also to attach the wrought-iron cup to the piston, and the
whole arrangement is such that the thrust of the piston when delivering
a blow throws no strain upon the bolts, the latter merely having to draw
the ram back on the return stroke. At a short distance from the head
the shaft is provided with a pair of lateral projections or lugs hollowed
on their under sides where they bear upon a pair of spheres which roll on
a suitable table formed on a base plate, and which carry almost the
entire weight of the shaft and head. The spheres are, in fact, so situated
that when the machinc is at half stroke they are almost directly under
the centre of gravity of the combined head and shaft, and thus the
piston is relieved of any excessive pressure which might cause it to wear
unduly. The two spheres are 1 ft. 5 in. apart laterally from centre to
centre, and they thus form a tolerably wide base, and serve to keep the
head from canting. At a short distance from the lugs just mentioned
the shaft has a swell formed on each side of it, as shown in the plan,
Figure 2, this portion of it fitting between a pair of guides cast on a
carriage, which is moved to and fro laterally by the traversing gear.
This gear is clearly shown by Figures 1, 2, and 3; it consists, in the first
place, of a lever, the upper end of which enters a recess in the under side
of the ram shaft, this recess being curved to an arc struck from the
centre of the spherical end formed on the shaft where the latter is

page_text: attached to the piston. The lever just mentioned is fixed on a rocking
shaft, which extends partially across the machine beneath the base plate,
and which carries two other levers, which are coupled, as shown in
Figure 1, to another pair of levers which oscillate on a second shaft, and
each of which carries a pawl gripping a wheel with a groove in its
periphery, the arrangement being similar to that known as Worssam's
silent feed motion. The shaft on which the V groove wheels are fixed
has a double-threaded worm formed on it, and this worm drives a worm
wheel fixed on a short vertical spindle, as shown in Figure 1. At the
upper end of this spindle is a pinion, which gears into a mangle rack on
the under side of the carriage by which the ram shaft is guided, and
thus imparts to this carriage, and consequently to the shaft, the to-and-
fro motion of which I have already spoken. The pawls which I have
mentioned are set to grip their wheels during the return stroke of the
ram, and it is during this return stroke consequently that the lateral
feed is given. The rate of this lateral feed can be altered by varying the
proportions of the levers according to the nature of the materials on
which the chisels have to operate. In the case of the machine shown in
the Drawings the parts are so proportioned that when the ram is making
the full length strokes of 6 inches the head will traverse from one side
of the gallery to the other in 66 strokes, and as the widths of the gallery
and ram head are 48 inches and 20 inches respectively this corresponds
to a feed of ±
= = 0.424 in. per stroke. If the ram is
worked with shorter strokes the feed per stroke will be proportionally
less.
48
20
66
28
66
Referring to Figure 1 it will be seen that the piston, which is 2 ft. 2 in.
in diameter has a trunk formed on each side of it, that on the front side,
or the side next the face of the rock to be operated upon, being 16 feet,
and that on the other side 19 inches in diameter.
The effective area
exposed by the piston is thus 329.87 square inches on the former and
2474 square inches on the latter side, or, say 330 and 247 square
inches respectively. The hind end of the cylinder is placed in direct
communication with the valve chest by a port of ample size, as shown in
Figure 1, so that the hind side of the piston is at all times subjected to
the full pressure of steam or air which exists in the valve chest. The
other end of the cylinder however has the steam or air admitted to it
and released from it by a multiported slide valve, of the mode of working
which I shall speak presently. The hind side of the piston being always

page_text: exposed to the pressure of the steam there is a constant tendency to
drive the ram against the rock, except at such times as the steam is
admitted to act on the larger area of the front side of the piston. This
arrangement is much preferable to one in which the steam is admitted
to each side of the piston alternately, as it enables the steam to be
effectively used expansively, and it saves much waste of steam when
working with short strokes. This will be clearly understood if it is
remembered that there is really no steam used in the hind end of the
cylinder (except that lost by condensation), the steam merely flowing
into that end of the cylinder and back again into the valve chest at each
stroke, and in fact forming a kind of steam spring which exerts a
constant pressure tending to force the ram forward. Again the quantity
of steam admitted to the front end of the cylinder is merely that
necessary to force the piston back the required distance, and thus give
the stroke required, and thus the amount of steam used becomes less as
the length of stroke is reduced. _On_the_other_hand-if-the-steam was
admitted to and exhausted from each side of the piston alternately there
would be a great waste of steam when working with short strokes, on
account of the large clearance spaces which would then exist, and the
steam used to fill these spaces.
Suppose the machine to be worked by steam or compressed air
supplied at such a pressure that an effective pressure of 100 lb. per
square inch can be obtained in the cylinder. In the machine shown the
total weight of the ram and its chisels, together with the piston, valve
rod, and other reciprocating parts is about 8,900 lbs., and inasmuch as by
far the greater part of this weight is carried by a pair of spheres on
which the ram shafts rest, 10 per cent. of this weight, or say 890 lb.,
may be taken as a fair allowance for friction, even including that of the
glands and piston. The effective area of the hind side of the piston
being 247 square inches there will be a constant pressure of 100 × 247.5
=24,750 lb. tending to force the piston forward whenever the steam is
exhausted from the other side. Deducting from this total pressure
890 lb. as the amount required to overcome the friction 24,750-890=
23,860 lb., available for putting the mass into motion and giving the
blow. This pressure is equal to =2.68 times the weight of the
23,860
8,900
reciprocation parts, and the velocity imparted to them by it will thus be
equal to that which they would acquire in falling from a height equal to
2.68 times the length of the stroke. If the machine is working with its

page_text: 8900
full stroke of six inches the velocity acquired will thus be due to a fall
of 0.5×2.68=1.34 ft. or 9.26 ft. per second. Again, the aggregate
length of the cutting edges exposed by the chisels is 1168 inches, and the
weight of the reciprocating parts being 8,900 lb., there is thus a mass
in motion of 8-7.62 lb. per inch of length of cutting edge. In other
words, when the machine is working in the manner I have just supposed,
each inch of cutting edge will have to resist a blow equal to that
produced by a weight of 7.62 lb. falling through a height of 1.34 feet.
This strain is about equal to that which would be produced on the
cutting edge of a jumper bar 14 inches in diameter, and 26 inches long,
if the bar was let fall from the height just mentioned. The above
calculation is made on the assumption that the force of the blow is
distributed equally over the whole length of cutting edge exposed by the
chisels, but of course in practice this would not be the case, and the
chisels would from inequalities in the rock be occasionally exposed to far
greater resistances at some points that at others. Under such circum-
stances it might perhaps be advisable to moderate the force of the blow
either by reducing the length of the stroke or throttling the supply of
steam or air, but this is a point which would have to be decided by
practice. The resistances to be overcome during the return stroke are
the friction and the pressure of the steam against the hind side of the
piston, or 890+24,750=25,640 lb. in all. The effective area of the
front side of the piston being 330 square inches, there is thus required a
mean effective pressure of
25,640 77-7 lb. per square inch throughout the
stroke.
330
With steam of an initial pressure of 100 lb. per square inch, or
say 115 lb. per square inch above a vacuum, the mean pressure just
mentioned would be given by about a two-fold expansion. In the
machine the port leading to the front end of the cylinder opens into the
latter about in. from the cover, this space being left to allow of a
cushion of steam or air being shut in by the piston in the event of the
latter being accidentally driven an undue distance forward from the ram
not meeting with the expected resistance, the cushion of air or steam
thus shut in protecting the cylinder end from impact with the piston.
Owing to this arrangement the total clearance spaces at the front end of
the cylinder amount to probably 500 cubic inches; and if the machine is
working with a 6 inch stroke the steam would consequently have to be
cut off at about 2 in. of that stroke to obtain a two-fold expansion.
Inasmuch however as the release will take place before the end of the

page_text: stroke, and will thus reduce the mean effective pressure during the
latter, it will probably be necessary to continue the admission until
nearly half stroke, in order to obtain the desired mean effective pressure
on the piston. During the early part of the return stroke the pressure
on the front side of the piston will be considerably in excess of that on
the opposite side, and this excess of pressure will be employed in putting
the reciprocating mass into motion, and storing up momentum which
will be given out again during the latter part of the stroke when the
pressure on the back will be in excess of that on the front of the piston.
There will be a considerable difference in the manner in which the
piston will move during the two strokes. During the return stroke the
parts will be put gradually into motion, and brought gradually to a state
of rest, while during the forward stroke the motion of the ram will be
gradually accelerated, and it will strike the rock when moving at its
greatest velocity. In order that this latter action may be obtained
perfectly it is necessary-that-the-admission-of-the-steam to the front end
of the cylinder (for causing the return stroke) should be delayed as
much as possible, and the valve gear, which I shall now proceed to
describe, provides for this.
.
Figures 8, 9, 10, show the slide valve and its attachments on an
enlarged scale, the three views respectively showing the ports full open
to steam, just closed, and full open to exhaust. It will be seen from
these views that the valve is able to give a large port opening for either
the admission or discharge of steam with a very short travel, the
admission and discharge each taking place through three ports which are
uncovered simultaneously. The valve spindle passes through a stuffing
box at the hind end of the valve chest, and is attached to a cross head
working on a suitable guide, the pin of this cross head passing through a
slotted link of the form shewn. The upper end of this slotted link is
coupled to one end of a pair of radius links, the other ends of which fit a
on studs projecting from a block which can be raised or lowered between
guides by means of a screw, as shewn. The lower end of the slotted
link on the other hand is coupled to the end of a lever keyed on a
rocking shaft extending across the hind end of the machine, this shaft
carrying also a pair of curved arms or levers which hang down and are a
coupled to the piston by a valve rod with a spherical end, in the manner
shown in Figure 1. It will be seen by tracing out this arrangement
that as the piston moves to and fro it will impart an up-and-down
-

page_text: movement to the slotted link, and the curved slot of the latter acting on
the pin of the valve spindle cross head will give to the valve the motion
required. When the block carrying the studs on which the radius liuks
oscillate is at its middle position an up-and-down motion of the slotted link
through a range of 3 in. produces the motion of the valve required for a
complete double stroke of the piston. In order to give the slotted link
this amount of up-and-down motion and at the same time enable the
stroke of the piston to be varied, the curved arms to which the valve rod
is attached are provided with holes at different distances from the
rocking shaft, as shown. By passing the pin which couples the valve
rod to the curved arms through one or the other of these holes the
length of the stroke can be varied at pleasure, it being merely necessary
that the distance from the centre of this pin to the centre of the rocking
shaft should bear the same proportion to the length of the arm giving
motion to the slotted link that the desired length of the stroke bears to
the necessary up-and-down motion of that link.
Provision is made for enabling the admission of steam against the
front of the piston to be delayed to as late a point in the forward stroke
as possible, and this provision, which is of especial use when working
with short strokes, I shall now explain.
Referring to Fig. 1 it will be seen that the curved arms on the rocking
shaft are not coupled rigidly to the valve rod, by which motion is given
to them. The coupling pin passes through a hole in a kind of sleeve
which encircles the valve rod at that point, and also through a long
slotted hole in the valve rod itself; and it follows from this arrangement
that any motion given to the curved arms must be transmitted by the
sleeve just mentioned. At each end of the sleeve and interposed
between it and collars fixed on the valve rod are india-rubber discs, as
shown in Fig. 1, that at the outer end merely serving to reduce the shocks
on the parts, while the pair on the inner side enable the opening of the
steam port leading to the front end of the cylinder to be delayed in the
manner I shall now explain, premising that the slotted link is so shaped
that any opening given to the front ports before the end of the forward
stroke remains until a considerable portion of the return stroke has been
accomplished. Suppose that the valve gear is so set that when the
machine is working slowly, say, making eight or ten strokes per minute,
the valve only very slightly opens the front ports for steam by the time
the blow is struck, and thus the return stroke is made gradually. If

page_text: with things so arranged the steam is turned on so as to produce a rapid
forward stroke, the curved arms on the rocking shaft will during this
stroke acquire considerable momentum, and on the motion of the piston
being arrested by the ram coming into contact with the rock they will
continue their forward motion for a short distance, moving the sliding
sleeve on the valve rod, and compressing the india-rubber rings against
which that sleeve bears. The effect of this will be to give an extra
upward movement to the slotted link, and consequently cause the valve
to uncover the ports to a greater extent for the admission of steam,
and thus an ample supply of steam will be admitted for causing the
return stroke to be made promptly, and this notwithstanding that the
commencement of the admission was delayed almost until the blow was
struck. The shorter the stroke with which the machine is being worked
the more effectively will the curved arms be able to cause by their
momentum the extra opening of the valve in the manner I have
described (as_the_shorter-the-stroke-of-the-piston-the-less will be the
distance between the point of attachment of the valve rod to the curved
arms and the rocking shaft), and it is really with short strokes that this
action will be most required. There is a peculiarity in the movement
of the slotted link which enables the stroke of the machine to be
varied within certain limits while at work without altering the point
at which the valve rod is coupled to the curved arms on the rocking
shaft.
Referring to Figs. 7, 8, and 9 it will be seen that the motion is given
to the valve not merely by the inclination of the sides of the slot in the
slotted link, but by the fact that the latter link is from the manner in
which it is hung transported horizontally for a certain distance during its
up-and-down movement. Referring now to Fig. 11 it will be seen that
by lowering the block carrying the studs on which the radius links
oscillate, the drawing forward of the upper end of the slotted link
during its downward stroke is delayed, and this is equivalent to decreas-
ing the steepness of the inclined side of the slot, and produces a later
cut off of the steam, and consequently a lengthened stroke. By raising
the block carrying the centres for the radius links an opposite effect is
of course produced. This mode of adjustment is useful in cases where
from unsuspected circumstances the stroke of the machine has to be
altered suddenly. Before leaving the cylinder and its connections there
is one other point on which I must say a few words. To diminish the.

page_text: chance of knocking out a cylinder end the ports have been made to so
enter the cylinder that the piston may pass them and shut in a cushion
of air or steam. If this occurrence took place in the course of regular
working, the steam or air thus shut in would exert sufficient force
to return the piston past the ports again, but it is possible that in
adjusting the machine or just at starting, the piston might get past
one of the ports and no means be at hand to get it back again. To
avoid the delay which such an occurrence might cause the cylinder is
fitted with pipes and cocks placed as shown in Figs. 1 and 2, so that
thic steam can be admitted from the valve chest to the extreme ends
of the cylinders, beyond the ports, thus enabling the piston to be readily
driven back again in the event of its passing the ports as above
supposed. The means provided for removing the debris is an important
feature in the machine. Across the front end of the machine there
is carried in suitable bearings a square shaft, and on this shaft are
placed a number of "rag" wheels as shown. At the back of the
machine is placed another transverse shaft, similarly provided, and
over the rag wheels on these two shafts are placed a series of endless.
chains of the well-known Vaucanson pattern so largely used on the
continent. The shaft at the hind end of the machine, carries, besides
the rag wheels a ratchet wheel which is driven by two pawls carried
by a rod which passes upwards and is coupled to a short arm pro-
jecting from the valve gear rocking shaft. The pawls just mentioned
are so arranged that one acts on the upward and the other on the
downward stroke of the rod carrying them, and thus an almost con-
tinuous motion is imparted to the rag wheel shaft, and consequently
to the chains passing over it. The chains droop on to the floor of the
gallery, and they form a kind of coarse moving web which will sweep
the débris from the front to the back of the machine, where it can
readily be removed. The bringing of the débris under the action of
the chain will be facilitated by the jets of water which will be made to
play upon the face of the rock while the chisels are acting upon it.
These water jets will probably suffice to keep the ledges at the bottom
corners of the tunnels clear of the débris, but if necessary brushes can
be attached to the ram to assist in performing this work. The moving
of the machine forward is effected by hydraulic jacks applied at the
rear end, as shewn in Fig. 6, and it is steadied by a series of. rollers pro-
jecting slightly from the sides of the framing, as shewn in Figs. 1, 2, 3, 4,
and 5, these rollers bearing against the sides of the gallery. The

page_text: machine may be driven either by compressed air or steam, and it will
depend upon the circumstances under which it is used which method of
working will be most desirable. The shape of the gallery made by
the machine offers great facility for the introduction of a steam boiler,
and Fig. 7 shows the manner in which such a boiler can be arranged
near the machine without interfering with the free removal of the débris.
The boiler there shewn is of the locomotive pattern, and has a barrel
2 ft. 6 in. diameter, by 6 ft. 9 long, and a fire-box casing 4 ft. 7 in.
long, by 2 ft. 6 in. wide, and 3 ft. 9 in. deep. This boiler would have
sufficient surface to convert thirty cubic feet of water per hour into steam
at a pressure of say 120 lb. per square inch. This quantity of steam
would be amply sufficient to drive the machine continuously at the rate
of 120 full length strokes per minute. The waste gases from the boiler
would be passed into a suitable air tube, from which they would be
exhausted by a fan situated at the mouth of the gallery or at any
other convenient point. The-boiler-it-will-be noticed is mounted on
wheels so that it can be casily moved forward on temporary rails laid
down as shewn in Figs. 6 and 7. I may mention that I propose to
employ tunnelling machines constructed on my plan for the formation
of tunnels of much larger size than that for which the particular
machine illustrated is adapted as I consider that such machines might
be employed to driving side by side a pair of galleries, each 14 feet high,
by 10 feet wide.
And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim as my
Invention,-
-
Firstly. The general construction and arrangement of machinery or
apparatus for tunnelling and forming galleries in mines, quarries, and
other places of a square or corresponding shape, substantially as described
and shown in the accompanying Drawings.
Secondly. I claim the employment of a tool holder of the form shown
and the mode of actuating the same, whether such be acted upon by
steam, compressed air, or other motive agency for the cutting of stone,
rock, or other material when forming tunnels, galleries, or other places,
substantially as shown and described.
Thirdly. I claim supporting cutting tool or tool head of tunnelling
or quarrying machines, upon spherical bodies, substantially as described
and shown.

page_text: Fourthly. I claim the special arrangement of mechanism for main-
taining a to and fro lateral movement of the cutting tool in combination
with the percussive action in such machines, substantially as described
and shown.
Fifthly. I claim the method of operating the mechanism for cutting
off the supply of motive agency in machines for tunnelling and quarrying
purposes whether employed in the machines before described or in other
machines of a similar construction.
Sixthly. I claim the employment of an articulated scraping apparatus
of the form shown and described for withdrawing the debris from the
front of the machine when cutting a square or correspondingly shape
tunnel or gallery.
And, lastly, I claim the means of facilitating an uninterrupted cutting
of tunnels and galleries by the introduction of an engine and cutting
apparatus complete in an opening of square or corresponding shape in
the manner herein-before described and shown in the accompanying
Drawings.
In witness whereof, I, the said Thomas Frederick Henley, have
hereunto set my hand and seal, this Twenty-fifth day of February
in the year of our Lord One thousand eight hundred and seventy-
ona