IMPROVEMENTS IN MACHINERY OR APPARATUS FOR DRIVING OR EXCAVATING TUNNELS OR GALLERIES AND FOR SINKING SHAFTS OR PITS
Year: 1876

page_text: LETTERS PATENT to John Dickinson Brunton, of Kentish Town, in the County
of Middlesex, for the Invention of "IMPROVEMENTS IN MACHINERY OR
APPARATUS FOR DRIVING OR EXCAVATING TUNNELS OR GALLERIES AND FOR
SINKING SHAFTS OR PITS."
Sealed the 8th December 1876, and dated the 20th June 1876.
PROVISIONAL SPECIFICATION left by the said John Dickinson Brunton at
the Office of the Commissioners of Patents on the 20th June 1876.
JOHN DICKINSON BRUNTON, of Kentish Town, in the County of Middlesex.
"IMPROVEMENTS IN MACHINERY OR APPARATUS FOR DRIVING OR EXCAVATING
TUNNELS OR GALLERIES AND FOR SINKING SHAFTS OR PITS."
My Invention relates to that description of machinery or apparatus for driving
or excavating tunnels or galleries and for sinking shafts or pits, in which one or
more sets of circular cutters (each mounted on a separate axis) is or are arranged
around a centre or centres revolving round a fixed centre which coincides with the
axis of the tunnel, gallery, or pit to be formed, such cutting discs, by their rotation
on their own axes as their common centre revolves round the fixed centre, cutting
away the rock or other strata against which they are caused to act.
The Invention consists chiefly of improvements upon a former Invention in
respect of which I obtained Letters Patent bearing date July 5th, 1866, No. 1784,
such improvements having reference more particularly to the construction of the
working parts and to the mode of imparting motion to the travelling wheels and to
the cutters, to the mode of collecting and removing the debris produced, and also to
a means for excluding dust from the working parts.
According to my present Invention I construct the cross head (described in the
Specification of my said former Letters Patent) which carries the cutter chucks
with its opposite ends angled or skewed in reverse direction to the axis of the
tunnel (for example) to be driven or formed, and I mount the chucks thereon at a
corresponding angle, whereby the cutters will be caused to act upon the rock or
other strata during only one half of the revolution of the chucks upon their arbors.
The portion of the chuck arbor which enters the chuck is made eccentric to the
portion contained in the cross head, for the purpose of admitting of the chuck being
adjusted by means of a lever, and gearing as the cutters become less in diameter by

page_text: wear, and also to allow of a small amount of variation in the diameter of the
tunnel to be formed.
The arbor when adjusted is secured in the required position by means of a sliding
bolt engaging with the teeth of the gearing. The cutters consist of a disc or
annular piece of steel secured between two cheeks, one of which is provided with
an internal screw thread fitting a corresponding thread formed on one of two
journals, with which the other cheek is provided.
The inner periphery of the steel cutting disc is bevelled, and is caused by the
screwed cheek to bear against a correspondingly bevelled projection formed on or
fitted to the other cheek, the screwed cheek serving as a nut to maintain the steel
cutting disc in position. The under side of the screwed cheek is provided with a
spring catch or detent which engages with ratchet teeth or recesses formed in the face
of the other cheek, and prevents the former from becoming loose or accidentally
turned in the wrong direction. A hole is provided in the screwed cheek for the
introduction of a suitable instrument to disengage the spring catch from the teeth
or recesses when it is required to remove the cutting disc.
The journals of the cutter are fitted to rotate in brasses carried by boxes mounted
or secured to the cutter chucks by means of wedges having teeth or serrations
engaging with a spring detent fitted to the body of the chuck, but which may be
disengaged therefrom when required by means of a key or handle fitted into the
spindle which carries the detent. In the ends of the boxes I fit steel back centre.
pins which enter the opposite ends of an opening or chamber formed in the interior
of the journals for containing lubricated material, and serve to receive the thrust or
pressure of the cutters when at work.
When a positive motion is imparted to the cutters, as described in the Specification
of Letters Patent granted to me bearing date the 25 February, 1875, No. 702, I
exclude dust from the gearing by the employment of a blast of air at a low pressure,
which is admitted into the interior of the hollow screw shaft which effects the
forward motion of the machine through an opening formed therein, and surrounded
by a hollow ring or collar communicating with the air-supply pipe. The air is
conducted along the hollow screw shaft through passages in the cross head into the
cutter chucks, thence through passages in the chucks into chambers formed in the
centre of the face of the chuck by a plate which encloses the gearing at that part,
from which chamber it then passes through other conduits to the face of the cutters
beneath a cap or cover fitted to or formed on the chucks, and finally escapes
between the edge of the cap and the face of the cutter. The positive motion may
be imparted to the cutters from the wheel which drives the chucks by mounting on
the boss of such wheel another wheel in gear with a pinion keyed on a spindle
which works in bearings in the cross head. This spindle carries another wheel
in gear with a corresponding wheel mounted on another spindle, which also works
in bearings in the cross head. On the outer end of the latter spindle there is keyed
a strap pulley carrying a strap which passes round a pulley keyed on one end of a.
spindle extending through the chuck arbor, and carrying at its opposite end a bevel
wheel in gear with three pinions (or any other number requisite, according to the
number of cutters which the chuck carries) on the spindles, of which there are
keyed other bevel pinions which drive bevel wheels fitted to or formed on the
cutters.
If required the blast of air may be employed when the positive motion is not.
used, or when such motion is obtained otherwise than by gearing. In order to
regulate the traverse of the cutters according to the degree of hardness of the rock
or other strata upon which they are caused to act I impart a rotatory motion to the
nut through which the screw shaft works, and regulate the speed of such motion
by means of change wheels, whereby any required forward traverse of the screw
shaft at each complete revolution may be obtained, whilst if it is required to
traverse the screw to an extent equal to the pitch of the screw at each revolution
this object may be effected by removing a portion of the gearing, and fixing the
nut by means of a key so as to prevent it from rotating.

page_text: The debris is removed from the front of the machine when at work by a rotating
'drum having attached thereto a number of scoops so arranged as that when the
drum rotates the scoops raise the debris from the bottom of the tumel and discharge
it over a plate into a shute with which it is provided for the purpose of conducting
it on to an endless travelling apron for conveying it to the rear of the machine.
The endless apron is supported upon rollers carried in a suitable frame, and is
actuated by means of chains and chain wheels, belts, or gearing, which impart
motion to carrying rollers provided with teeth or projections engaging with bars of
wood fixed to the back side of the endless apron. In order to remove any of the
debris which may gain access to the interior of the endless apron I arrange therein
a trough and an archimedian screw, which receives and conveys such debris
through an opening in the supporting frame into the tunnel by the side of the machine.
The whole of the cutting mechanism, together with the engine for imparting
motion thereto, is carried on a strong frame mounted on running wheels, on the
axles of which there are keyed worm wheels driven by means of worms mounted
on horizontal shafts actuated by the engine which drives the cutting mechanism.
When the cutting mechanism is in action the wheels employed for transmitting
motion from the engine to the shafts carrying the worms are thrown out of gear,
and the worms are maintained in motion by means of a small air engine of just suffi--
cient power to actuate them and to cause them to follow the motion of the running
wheels so as to prevent the jamming action which would be liable to take place if
no motion were imparted to the gearing. When however it is required to move
the machine to and fro the cutter mechanism is thrown out of gear by means of
clutches provided for the purpose, and the wheels for transmitting motion from the
engine to the running wheels are brought into gear, whereby the required travelling
motion will be obtained.
My improved apparatus for sinking shafts or pits consists of a peculiar arrange-
ment of machinery, whereby a frame keyed on the lower end of a screw shaft and
carrying a cutter chuck and cutters is caused to rotate by means of a worm mounted
on the frame and travelling around a stationary or non-rotating worm wheel. In
carrying out this part of my Invention I mount the cutter chuck in a bracket
projecting from the rotating frame or carriage, and impart motion thereto around
its own axis by means of a spur wheel with which it is fitted gearing on to a cor-
responding wheel keyed on the lower end of a spindle extending through the
hollow screw shaft. This spindle carries at its upper end a bevel wheel in gear
with a bevel pinion keyed on the driving shaft, which is mounted on a frame fixed
to the sides of the shaft or pit, and receives motion from an air engine or other
prime mover. To the under side of the fixed frame there is secured a long boss or
collar, having hinged thereto three arms extending upwards in an inclined direction
with their outer ends abutting against the interior of the shaft or pit so as to
constitute a point of resistance for carrying the machine downward as the cutting
proceeds.
The screw shaft engages in a nut which is maintained stationary by being keyed
to the long boss or collar last described, and such screw shaft is caused to rotate
and at the same time impart an orbital as well as a descending motion to the chuck
in the following manner:- -The spur wheel keyed on the lower end of the spindle
which passes through the screw shaft is caused to gear with a corresponding wheel
fast on the lower end of a spindle which works in bearings in the frame or carriage
supporting the cutter chuck, and carries at its upper end a bevel pinion in gear with
a bevel wheel mounted on a horizontal shaft in the same carriage. On this shaft
there is keyed a worm, which as the former rotates is caused to travel round a
stationary worm wheel connected by means of a clutch to the nut through which
the screw shaft works. The worm in travelling round the stationary worm wheel
carries with it the frame or carriage upon which it is mounted, and which by being
keyed into the lower end of the screw causes the latter to rotate in the stationary
nut, and advance forward to an extent equal to the pitch of the screw at each
revolution.

page_text: The rotatory motion of the screw shaft may be suspended when required by
simply uncoupling the clutch which connects the stationary worm wheel with the
fixed nut, when the cutter chuck will continue to rotate on its own axis without
receiving either an orbital or descending motion.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Dickinson Brunton in the Great Seal Patent Office on the 18th
December 1876.
JOHN DICKINSON BRUNTON, of Kentish Town, in the County of Middlesex.
"IMPROVEMENTS IN MACHINERY OR APPARATUS FOR DRIVING OR EXCAVATING
TUNNELS OR GALLERIES AND FOR SINKING SHAFTS OR PITS."
My said Invention relates to that description of machinery or apparatus for
driving or excavating tunnels or galleries, and for sinking shafts or pits in which
one or more sets of circular cutters (each mounted on a separate axis) is or are
arranged around a centre or centres revolving round a fixed centre which coincides
with the axis of the tunnel, gallery, or pit to be formed, such cutting discs by their
rotation on their own axis as their common centre revolves round the fixed centre,
cutting away the rock or other strata against which they are caused to act.
The Invention consists chiefly of improvements upon a former Invention in
respect of which I obtained Letters Patent, bearing date July Fifth, One thousand
eight hundred and sixty-six, No. 1784, such improvements having reference more
particularly to the construction of the working parts and to the mode of imparting
motion to the travelling wheels and to the cutters, to the mode of collecting and
removing the debris produced, and also to a means for excluding dust from the
working parts.
And in order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for that purpose shall refer
to the several Figures on the annexed four Sheets of Drawings, the same letters of
reference indicating corresponding parts in all the corresponding Figures.
Figure 1, Sheet 1, of my Drawings represents a longitudinal sectional elevation
of a tunnelling machine constructed according to my Invention; Figure 2 is a
corresponding plan of the same; Figure 3 is a transverse section taken along the
line 1, 2, in Figure 1; Figure 4 is a similar section taken along the line 3, 4,
Figure 1; and Figures 5 to 25, Sheets 1, 2, and 3, are details and modifications
which will be herein-after referred to.
Figure 26, Sheet 4, represents an elevation of an apparatus suitable for sinking
shafts or pits; Figure 27 is a vertical section of the same; Figure 28, a plan; and
Figure 29, a horizontal section, all corresponding to Figure 26.
Referring to Figures 1, 2, 3, and 4, Sheet 1, A, A¹, represent two strong cast-iron
beams mounted upon running wheels B, B, and connected together at or near their
ends by carriages or standards C, C, carrying the driving mechanism for actuating
the cutters D and for propelling the machine forward as the work proceeds. The
cutters D are fitted to rotate in bearings E in chucks F (two of which are by
preference employed) mounted on opposite ends of a cross head G keyed on the front
end of a hollow screw shaft H, which works in bearings I in the carriages C, C¹.
The chucks F (each of which carry by preference three cutters) are mounted upon
arbors K, and are each formed or fitted with a toothed wheel L, gearing with a
spur wheel M keyed on one end of a shaft N which works in bearings or brasses O
fitted in the interior of the hollow screw shaft H. The shaft N extends through
the hollow screw shaft H and carries at its end, opposite to that which carries the
wheel M, another spur wheel P which gears with a pinion Q carried on the shaft R
of a three cylinder air or other motive power engine S securely bolted on to the
beam A. Upon starting the engine S motion will be transmitted through the
gearing Q, P, shaft N, and spur wheel M to the chucks F, causing them to rotato

page_text: and carry with them the cutters D, the peripheries of which by reason of the
cutter axes being arranged at an angle to the axis of the tunnel (as shewn will be
caused to rotate against the surface of the rock or other strata and to chip or cut
pieces therefrom.
In addition to the axial motion imparted to the chucks they also receive an
orbital motion around the shaft N which is obtained in the following manner :—
Upon the hollow screw shaft H, carrying the cross head G, there is keyed a worm
wheel T in gear with a worm U fitted to or formed on a vertical shaft or spindle V
which works on bearings W, X, (Figure 3) on the carriage or standard C, and the
upper end of which carries a bevel wheel Y fitted loosely on the shaft, but caused
to rotate therewith when required by means of a clutch Z actuated by a lever a.
The bevel wheel Y gears with a bevel pinion b keyed on one end of a transverse
horizontal shaft c working on bearings d in the carriage C, and carrying at its
opposite end a spur wheel e in gear with a spur pinion e¹ mounted on a short
spindlef. This spindle is carried in brackets or arms g, g, attached to. the carriage C
and to the beam A¹, and on it there is also keyed a strap pulley h, round which
passes a strap i leading from another strap pulley k fast on one end of a horizontal
shaft which works in bearings m on brackets formed on the rear ends of the
beams A, A', a bevel wheel n being keyed on the opposite end of the shaft which
gears with a bevel pinion o keyed on the engine shaft R. The chucks thus travel
in a circular path round the shaft A, causing the cutters D to act upon the whole
surface (except a small core in the centre) of the end of the tunnel or gallery in
course of formation, against which surface they are maintained in contact by the
screw shaft H passing through a nut p. This nut is maintained stationary, that is
to say, is prevented from receding on a longitudinal direction by means of two
telescopic arms q hinged to the opposite sides thereof, and bearing at their outer
extremities against the interior of the tunnel in an inclined direction towards the
back of the machine, the arms being placed horizontally or nearly so and adjusted
and fixed at the required inclination by means of the nut r. When the screw
shaft H has passed through the nut p, that is to say, when the machine has worked
or cut its way into the rock or other strata to a distance equal to the length of the
screw spindle H, or at an earlier period, if necessary, the nut p is caused to travel
along the screw to the front end thereof by operating the gearing t (herein-after
fully described) by means of the crank handle 8, and is fixed in that position by
the arms q, the same operation being repeated as often as necessary.
The debris is removed from the front of the machine by means of six or any
other suitable number of scoops u, rivetted or otherwise secured to a rotating drum
or centre piece v which elevate and deposit it upon an endless travelling apron w,
by which it is conveyed to the rear of the machine. The drum v is provided with
a collar or long boss a fitted to rotate on a smooth prolonged portion of the hollow
shaft H between the carriage C and the cross head Ĝ. On this boss there is keyed
or cast a worm wheel y which gears with a worm z, carried on a horizontal shaft
or spindle one which works in bearing 2 on the carriage C, and carries at its outer
end a spur pinion 3 in gear with a spur wheel 4 on another short spindle 5, which
also carries another spur pinion 6 in gear with a spur wheel 7 keyed on the shaft c.
It will thus be seen that when the machine is at work the drum v and the scoops u
will be caused to rotate and elevate the debris which collects in front of the
machine. The back ends of the scoops u are open and work in contact with a
metal segmental plate 8 attached to the inner ends of the beams A, A¹, over which
plate the debris is discharged by the scoops in their ascent into a spout or shute 9,
by which it is conducted on to the endless travelling band or apron w. This band
is supported upon rollers 10, 11, working in bearings in a frame 12 which is sup-
ported on arms 13, fitted with running wheels 14 to facilitate its motion with the
machine as it works its way into the rock or other strata.
Motion is imparted to the apron w from the horizontal shaft 1 in the following
manner-The shaft carries a strap pulley 15, over which passes a strap 16 to a
pulley 17, keyed on a horizontal shaft or spindle 18, which works in bearings on

page_text: •
the under side of the frame 12. This spindle carries at its outer ends two chain
wheels 19, 19, one of which carries a chain 20, passing round a chain wheel 21,
keyed on one end of the roller B which works in adjustable bearings 22 in the
rear end of the frame 12, whilst the other wheel 19 carries another chain 23, which.
passes round a pulley 24 on the axle of the roller 10 situate at about the centre of
the frame 12.
By the combined action of these chains the apron w is caused to travel evenly
throughout its length, thereby ensuring the debris being conveyed to the rear of
the machine where a truck or other receptacle may be arranged to receive it; 25 is
a roller carried on a bracket attached to the frame 12, and caused to bear upon the
edge of the apron w for the purpose of maintaining it in contact with the rollers 11
at that part.
In order to keep the machine firmly down when at work planks of wood, not
shewn in the Drawing, are placed between the roof of the tunnel and the rollers 26,
carried on the upper ends of the projecting arms 27 of the carriages C, C¹, along
which planks the rollers travel as the cutting proceeds.
In addition to the forward motion of the machine obtained by means of the.
screw shaft H and the fixed nut p, as herein-before described, an independent
motion thereof is obtained in the following manner: To each of the 3 forward
running wheels B, on both sides of the machine, there is keyed a worm wheel 28,
with which gear worms 29 carried on two longitudinal spindles 30 mounted in
bearings in the two beams A, A. Each of these spindles carries on one end thereof
a worm wheel 31 in gear with worms 32, carried on a transverse shaft 33, mounted
in bearings in brackets m³, formed on the back ends of the beams A, A¹. This
shaft is actuated from the shaft by the wheels 34, the motion of which is trans-
mitted through the worms and worm wheels 32, 31, 29, and 28, to the running
wheels B, thus enabling the machine to be travelled to and fro, as required, without
operating the cutters by simply throwing the pinion Q out of gear with the spur
wheel P by means of the clutch 35 which connects the pinion with the engine
shaft R, and also by uncoupling the clutch z from the wheel Y.
In order to keep the worms 29 free on the worm wheels 28 during the time that
the machine is at work so as to prevent any jamming action, I throw the wheels 34
out of gear and connect the shaft 33 to a small air engine of just sufficient power to
maintain the worms 29 rotating and following the motion of the worm wheels 28.
Having thus described the general arrangement and mode of operating the appa-
ratus, I shall now proceed to describe the construction of the most important parts
thereof.
Figure 5, Sheet 1, is a sectional view of one of the disc cutters D; Figure 6 is a
plan, and Figure 7 a sectional detail of the same. The cutter consists of an annular
piece of steel D, having its outer periphery bevelled in order to form a cutting edge,
as shewn at a, its inner periphery being also slightly bevelled, as shewn at b, for the
purpose of insuring its being held steadily and firmly against a corresponding
inclined or bevelled surface c, formed on a disc A. The latter disc is provided with
journals B projecting from both sides thereof, one of which has a screw thread a'
formed on it for the reception of a screwed disc or washer C, between which washer
and the disc A the cutting disc D is securely held. The inner periphery of the
cutting disc D may be so arranged as to bear direct against the projection portion d
of the disc A if desired, but I prefer to interpose a ring of wrought iron or other
suitable metal between the disc D and the projection d, as shewn at e.
In the surface of the projecting portion d there are formed a number of indents
or ratchet teeth g, with which a spring detent n (Figure 7) attached to the screwed
disc or washer C is caused to engage in the process of screwing it down on to the
cutter D. This epring detent prevents the washer from being accidentally loosened
or turned backwards, but it may be removed when required by inserting any
suitable instrument into an aperture i, and raising the spring detent out of contact
with the teeth.
The journals B, B, rotate in brasses fitted in malleable iron blocks E, Figures 8

page_text: and 9, Sheet 1, in which there is screwed a hardened steel centre pin k, which
enters an opening / formed in and extending through the journals for containing
lubricating material; these centre pins serve at the same time as plugs for closing
the lubricating chamber and as a means of receiving the thrust of the cutters.
The blocks E are provided with recesses or grooves m, m, which fit on to corre-
sponding projections or ribs n formed on the cheeks of the chucks F (one of which
is shewn in front elevation in Figure 10, and in vertical section in Figure 11,
Sheet 2), and the said blocks are held securely in the chuck by means of a wedge o
retained in position by a spring detent p, which engages with ratchet teeth q formed
on the wedge o, but which may be disengaged from the teeth by means of a key
fitting a square on the end of the spindle r, upon which the detent is mounted, in
order to admit of the removal of the wedge. The chuck F, represented by Figures
10 and 11, Sheet 2, which is constructed to carry 3 cutters (but may be constructed
to carry any other desired number), is mounted on an arbor & carried in one end of
the cross head G, and that portion of the arbor 8 on which the chuck F rotates is
made eccentric with the portion contained in the cross head in order to enable the
position of the cutters to be adjusted as they become reduced in diameter by wear,
and also to admit of a small amount of variation in the size of the tunnel.
8
This adjustment is effected by means of a worm wheel t (Figures 11 and 11,
Sheet 2) keyed on to the portion of the arbor which projects behind the cross head,
and engaging with a worm t¹ (Figure 1) fitted to or formed on a spindle supported
in lugs on such cross head. The spindle is actuated by means of a key or handle,
so as to rotate the worm wheel and with it the arbor 8 to any desired extent, after
which the wheel and the arbor are retained in their adjusted position by means of a
sliding piece u (Figures 11 and 11a), which is caused to engage with the teeth of
the wheel t, and is firmly screwed to the back of the cross head.
Figure 12, Sheet 2, represents an end view of the cross head G, on reference to
which it will be seen that the ends G1, G2, are angled or skewed in opposite
directions and that the centres 35 and 36 of the bearings for the two chuck arbors
are also angled or skewed to correspond, whereby the chucks are arranged in a
position askew or oblique to the axis 37, in order to prevent the cutters from
coming into contact with the face of the tunnel during the back half of the
revolution of the chuck. The teeth of the wheel on the chucks, and also the teeth
of the wheel by which they are driven, are so constructed as to admit of the adjust-
ment of the chuck and the cutter, as before mentioned, and are skewed to correspond
with the skew or angle of the chuck.
Figure 13, Sheet 2, is a sectional plan of the stationary nut, herein-before referred
to, through which the screw shaft passes as the cutters work their way into the
rock or other strata, and Figure 14 is an end view of the same. A is the nut
provided with an internal screw thread A¹, and surrounded by a collar B having
lugs C, C, formed thereon, to which the arms q are hinged. These arms (of which
only one is shewn) are made telescopic, the outer extremity of the adjustable portion
being made to abut against the interior (usually the sides) of the tunnel, and to
constitute the point of resistance from which the screw as it works in the nut
carries forward the whole of the machine. From the collar B projects a bracket D.
carrying at its outer end a spindle E, on one end of which there is keyed a spur
wheel F in gear with a corresponding wheel G keyed or formed on the nut A
whilst the other end of such spindle carries another spur wheel H in gear with a
wheel I mounted on the screw shaft. The wheel I is made in two parts (for
the convenience of changing) connected together by bolts or pins passing through
lugs 38 (Figure 13ª) projecting from the sides of the periphery of the two portions
of the wheel. On the interior of one portion of this wheel there is provided a
projection or tongue x which enters a longitudinal slot formed in the screw shaft,
by which means as the screw rotates it carries with it the wheel I, whilst at the
same time the screw is free to traverse through the wheel. The wheel in its
rotation transmits motion through the wheels H, F, and G, to the nut A, the speed
of rotation of which, relatively to the speed of rotation of the screw shaft, will be

page_text: in proportion to the size of the wheels H and I, which constitute change wheels, by
the removal of which and the substitution of others of a different proportion the
amount of the forward traverse of the screw shaft at each revolution may be varied
as required. When it is desired that the traverse of the screw shaft at each
revolution shall be equal to the pitch of the screw the wheels H, I, are removed
and the nut A is prevented from rotating by being made fast with the collar B by
means of a key or bolt, or by any other suitable means.
Figure 15, Sheet 3, is a back elevation on an enlarged scale of a portion of the
delivery drum v, with its scoops u and the over-fall plate 8 illustrated by Figures 1
and 2, Sheet 1, and Figure 16, Sheet 3, is a sectional plan of the same.
The
drum v is composed of iron plates rivetted together in a conical form and bolted to
a centre piece, consisting of a boss and arms (cast in two parts for convenience)
with a worm wheel thereon, as herein-before described. To this drum there are
bolted six, or any other convenient number of scoops u of a curved tapering trough
shape and arranged at an angle of, say 45° to the axis of the tunnel, the edges of
which scoops, as the drum rotates, scrape the interior of the tunnel and collect the
debris from the bottom, whilst their back ends, which are open, work in contact
with the over-fall plate 8, as before mentioned. This plate extends upwards on
one side to about the height of the centre of the tunnel, so that as soon as the
scoops rise above the end of the plate the debris will slide out of the back end of
the scoops into a spout or shute A formed on the back of the plate, by which it is
conducted on to the endless apron w, and thence conveyed to the rear of the
machine.
The delivering endless apron w is composed of tarred canvas (similar to that
employed for the sails of ships) with its edges strengthened by cords strongly sewn
thereto. To the back of the apron are attached bars of wood 39, 39, as shewn in
the enlarged detail, Figure 17, Sheet 2, secured by means of screws and washers or
otherwise, and arranged at a suitable distance apart, to gear with the teeth a of the
driving roller B₁ and the drum 10. This band is supported on two series of
rollers 11, as herein-before described and shewn in Figure 1, the upper series being
supported in metal beams b attached to the interior of the carrying frame 12, as
shewn in Figures 18, 19, and 20, Sheet 2, whilst the lower series are supported in
bearings c secured to the under edge of the frame 12; passages d are made through
the frame 12 leading to the journals of the lower series of rollers for the introduction
of lubricating material to ensure the free rotation of the rollers, other passages e
being also made at an angle through the sides of the frame for the introduction of
oil into a chamber provided at the back of the metal beams b, in which the journals
of the upper series of rollers rotate, whereby the said journals are maintained in a
perfectly lubricated condition.
The front ends of the side beams of the supporting frame 12 are fitted with
terminal castings or shoes f, in which the lower supporting roller 11a has its
bearing. The axis of this roller carries a spur pinion g, as shewn in Figure 19,
Sheet 2, in gear with a spur wheel h, which is keyed on one end of a transverse
shaft i, carrying an archemedian screw k, the latter being caused to rotate in a
trough situate within the endless apron w, and in contact with the roller 11ª.
The object of this arrangement is to catch any of the debris which may find access
to the interior of the apron, and prevent it from being carried perpetually round
and round the roller 11ª by conducting it after it has passed once round 11a and
fallen into sidewise through an opening m in the beams into the tunnel by the
side of the machine.
The gearing g, h, is protected by an enclosing guard or cover n, and round the
lower end of the frame 12 there is fitted another guard n¹ composed of sheet iron,
and which is made to extend from one side of the frame to the other, so as to
protect that portion of the apron whilst the hopper-like form of the shute or spout
A (Figures 15 and 16), Sheet 3, causes the debris to be deposited in the middle
thereof.
{ The framing 12 is supported at its rear end by the arms 13, as herein-before

page_text: described, whilst it is further supported at about the middle and at the lower end
by wrought-iron straps connnected to the side beams A, A¹, Figures 1, 2, 3, and 4
Sheet 1.
Figure 21, Sheet 3, is a vertical section, shewing a modified construction of the
cross bead, and an arrangement for imparting a positive motion to the cutters.
Figure 22 is a back elevation of the same; and Figures 23, 24, and 25 are details
of portions of the apparatus.
A is the cross head, carrying at its opposite ends the cutter chucks B, one only
being shewn in my Drawings mounted on the eccentric arbor C; D is the central
wheel keyed on the spindle or shaft (not shewn in these Figures), which extends
On the boss of this
through the screw shaft H, and drives the two chucks B.
wheel there is keyed a spur wheel E in gear with a pinion F carried on one end of
a shaft or spindle G, which works in bearings in the cross head A, and is provided
with a spur wheel H gearing with a spur wheel H keyed on another shaft I, also
working in bearings in the cross head A. On the outer end of the shaft I there is
keyed a belt pulley K carrying a belt L, which passes round and drives a pulley M
fast on one end of a spindle N. This spindle extends through the chuck arbor C,
and carries at its opposite end a bevel wheel O in gear with three bevel pinions P
(one only being shewn in my Drawings) mounted on spindles which work in
bearings in the chuck B, and carry at their opposite ends other similar wheels Q in
gear with wheels R fitted to or formed on the inner plate of each of the three
cutters S. It will thus be seen that in lieu of the cutters being caused to rotate on
their axes only by their frictional contact with the rock or other strata being
operated upon, as in the arrangement first herein-before described, they receive a
positive rotatory motion from the central wheel D, their speed of rotation being
capable of variation when required by changing the belt pulleys K and M. The
chuck arbor C may be adjusted for the purpose of regulating the position of the
cutters with reference to the diameter of the tunnel by means of a spur wheel T
mounted on the end of the arbor C, and actuated or turned by means of a lever U
engaging with the teeth of the wheel T, a sliding bolt V also engaging with the
teeth, being employed for the purpose of retaining the arbor in its adjusted position
in a similar manner to the sliding piece u, Figures 11 and 11ª, in the arrangement
first herein-before described.
The wheels O, P, are protected from dust and injury by being enclosed by a
plate W screwed to the face of the chuck B, and the wheels Q and R are similarly.
protected by a cap X formed on the face of the chuck.
In order to more effectually exclude the dust from the working parts of the chucks
I employ a blast of air at a low pressure, which is introduced into the interior of
the screw shaft H carrying the cross head through an opening Y, Figure 23, com-
municating with a collar Z to which the air supply pipe a is connected. The air
thus admitted is conducted from the interior of the screw shaft through passages b,
Figure 21, formed in the cross head A into the space c between the plate W and
the face of the chuck, whence it passes through the passages d into or beneath the
cap X, and finally escapes between the face of the cutter and the rim or edge of the
cap X.
Figure 26, Sheet 4, represents an elevation of a machine constructed according to
my Invention, and intended more particularly for sinking shafts or pits in a vertical
or nearly vertical direction; Figure 27 is a vertical section; Figure 28, a plan;
and Figure 29, a horizontal section of the same, all corresponding to Figure 26.
A, A, are disc cutters constructed in a similar manner to those herein-before
described, and mounted in a chuck or holder B, which is supported in a bracket C
projecting from a carriage D keyed on the lower end of the hollow screw shaft E.
The chuck B has an axial motion imparted thereto by means of a spur wheel F
gearing with a corresponding wheel G keyed on the lower end of a spindle H, which
spindle extends through the hollow screw shaft E, and carries at its upper end a
bevel wheel I in gear with a corresponding bevel wheel K keyed on the driving
shaft L. The shaft L is mounted in bearings in a frame M fixed by means of

page_text: screws O to the interior of the shaft or pit, and is driven from an air engine or
other suitable prime mover by means of a strap passing round the pulley N. To
the under side of the frame M there is secured a long boss or collar P having hinged
to its lower end three arms Q, which extend upwards in an inclined direction, and
abut at their outer ends against the interior of the shaft or pit, so as to constitute
à point of resistance for carrying the machine forward as the cutting proceeds.
The screw shaft E works in a nut R maintained stationary by being keyed fast to
the under side of the collar or boss P, and the rotatory motion of such shaft and the
consequent planetary motion of the chuck is obtained in the following manner:-
In gear with the spur wheel G keyed on the lower end of the spindle H is a spur
wheel S fast on a vertical shaft T, which also carries a bevel pinion U in gear with
a bevel wheel U¹ keyed on a shaft V supported by the carriage D. On the shaft V
there is keyed a worm W, which as the spindle V rotates is caused to travel round
a stationary or non-rotating worm wheel X fitted to or formed on the lower end of
a sleeve or long boss Y; this boss surrounds the prolonged portion a of the nut R,
and is connected thereto by a clutch Z adapted to slots formed therein. so as to
admit of the clutch with the sleeve descending as the work proceeds. The worm W
în travelling round the wheel X carries with it the carriage D and the chuck B,
whereby the latter receives an orbital motion round the shaft or spindle H, in
addition to its axial motion, whilst at the same time the screw shaft E will by
reason of its connection with the carriage D be caused to rotate in the fixed nut R,
and will descend to an extent equal to the pitch of the screw at each complete
revolution, the worm wheel X with its sleeve Y also descending by gravity to the
extent allowed by the descent of the carriage.
If for any reason it becomes necessary to prevent the screw shaft from rotating,
and consequently from making any forward motion, this object may be effected by
simply uncoupling the clutch Z from the sleeve Y, which will then be caused to
rotate by the worm W, the latter together with the frame D, remaining stationary,
whilst the chuck with its cutters will continue to work on its own axis without
receiving either an orbital or an advancing motion.
Having now described and particularly ascertained the nature of my said Inven-
tion, and the manner in which the same is or may be used or carried into effect, I
would observe in conclusion that what I consider to be novel and original, and
therefore claim as the Invention secured to me by the herein-before in part
recited Letters Patent is,-
First. The general construction, arrangement, and combination of machinery or
apparatus for driving or excavating tunnels or galleries, substantially as herein-
before described and illustrated by my Drawings.
Second. The general construction, arrangement, and combination of machinery
or apparatus for sinking shafts or pits, substantially as herein-before described and
illustrated by my Drawing.
Third. The mode of securing the cutting disc between two other discs by screwing
one on to the other, and retaining the screwed disc in position by means of a spring
catch and ratchet_teeth or recesses, substantially as herein-before described and
illustrated by my Drawings.
Fourth. Providing steel centre pins in the malleable iron bars carrying the
cutting discs for the purpose of closing the lubricating chamber, and of receiving
the thrust of the cutters when at work, substantially as herein-before described and
illustrated by my Drawings.
Fifth. Securing the boxes in which the cutters are mounted to the rotating
chucks by means of wedges provided with notches or serrations engaging with a
spring detent, substantially as herein-before described and illustrated by my
Drawings.
Sixth. Mounting the chucks which carry the cutters upon eccentric arbors, sub-
stantially as and for the purpose herein-before described and as illustrated by my
Drawings.
-
Seventh. The application and use of a collecting or receiving trough and an

page_text: archemedian screw in the interior of the delivery apron for the purpose of carrying
away any of the debris which may enter therein, substantially in the manner
herein-before described and illustrated by my Drawings.
Eighth. The peculiar mode of imparting a positive rotatory motion from the
boss of the wheel which drives the chucks to the disc cutters when the chucks are
mounted upon eccentric arbors, substantially as herein-before described and illus-
trated by Figures 21, 22, and 25, Sheet 3, of my Drawings.
Ninth. The mode or method of excluding dust from the working parts of the
cross head and chucks by the employment of a blast or current of air which is
caused to circulate therethrough, substantially as herein-before described and illus-
trated by my Drawings.
Tenth. Imparting a travelling motion to the machine from the engine shaft when
the cutting mechanism is out of action by means of gearing, and maintaining the
gearing employed for propelling the machine in motion during the time that the
cutting mechanism is in operation, substantially as and for the purposes herein-
before described and as illustrated by my Drawings.
In witness whereof, I, the said John Dickinson Brunton, have to this my
Specification set my and hand seal, the Fourteenth day of December, One
thousand eight hundred and seventy-six.