IMPROVEMENTS IN TUNNELING AND EXCAVATING APPARATUS
Year: 1881

page_text: LETTERS PATENT to Albert Livingstone Blackman, of the City of Nashville,
State of Tennessee, United States of America, but temporarily of Southampton
Buildings, in the County of Middlesex, Gentleman, for an Invention of
.
PROVISIONAL SPECIFICATION left by the said Albert Livingstone Blackman
at the Office of the Commissioners of Patents on the 16th August 1881.
ALBERT LIVINGSTONE BLACKMAN, of the City of Nashville, State of Tennessee,
United States of America, but temporarily of Southampton Buildings, in the County
of Middlesex, Gentleman. "IMPROVEMENTS IN TUNNELING AND EXCAVATING
APPARATUS."
This Invention relates to the apparatus employed for tunneling or excavating
for railways, canals, or other works in which large quantites of sand, gravel, soil,
or other material have to be removed.
.
The Invention consists of the arrangement and combination of parts forming the
apparatus hereinafter described; by which tunneling or excavating may be rapidly,
safely, and economically carried out.
•
In the apparatus employed for tunneling a conical shaped boring head is used
provided with suitable cutting blades secured by arms to a hollow shaft which is
supported in bearings carried by the bed plate. Within said hollow shaft revolves
a shaft carrying a screw conveyer, for purposes hereinafter described, both of the
shafts being driven from a steain or other engine by means of suitable gearing.
When the machine is forced ahead, which may be accomplished by suitable
gearing, and the boring head revolves, the cutting blades will cut or tear away the
earthy substances with which they come in contact, the earth cut being forced by
the act of removal into and through a throat or channel and into the hollow shaft,
through which it is continuously carried by means of the screw conveyer, which
delivers it at the rear end of the hollow shaft into a suitable chute, from which it
may be conveyed in buckets travelling on an endless rope running over sheaves to
A

page_text: an elevator or other delivery point; said rope may be kept taught as the machine
advances by means of pulley and weights analogous to those employed in some
hydraulic and other lifts.
The screw conveyer is preferably driven at a higher speed of rotation than the
boring head in order that the hollow shaft and its connected throat or channel may i
be kept clear and free from clogging.
The operation of the machine, as before described, will bore or excavate a
cylindrical or partially cylindrical hole or channel of a size corresponding to the
diameter of the cutting head in any kind of earthy deposit not too hard to resist
the action of the cutter or cutters, the material cut being rapidly and automatically 1
removed and deposited in the rear of the machine, as before described.
A hollow cylindrical follower of a diameter slightly less than the boring head is
provided for the purpose of resisting downward or lateral pressure of the earth
surrounding the bore, and holding it in place until the masonry or iron plate lining
of the tunnel or excavation can be advanced to that point, it being intended that 1
the operation of lining shall generally keep pace with the boring, and that the
lining shall or may be put together inside of the follower, which is carried forward
on rollers fixed to the rear end of the boring head. The lining being put together
within the follower, it is requisite to prevent water or mud from entering the rear
of said follower, and thus penetrating into the lined tunnel; this end I attain by 2
securing within the follower a rubber, leather, or other suitable packing, which is
kept against the lining sections by means of a ring or pipe of rubber placed beneath
it, and secured in a suitable groove. The track upon which the machine rests and
runs is made in short sections, which are successively brought forward as the
machine advances, and laid down before it on the lining. In forming tunnels the
lining is preferably of cast iron, made in sections bolted together so as to form
a continuous and rigid tube, or brick work may be used for such lining. A
convenient manner of placing and securing these sections in position is as
follows:-
The upper plates or brick segments are raised and held in position until bolted:
or secured to the lining already finished by means of levers fastened to a collar
revolving freely on an eccentric, which in its turn revolves freely on the hollow
shaft. The section to be raised may be secured to the end of one of the levers.
When the required force is applied to the lever it will revolve the collar, which
with the eccentric will carry the section up to the required position, and hold it
there until permanently secured. The joints may be made water tight by means
of suitable packing.
The boring head being of a larger diameter than that of the lining it is necessary
to so construct it that its diameter may be reduced when obstructions to the
forward progress of the machine are encountered, or when from other causes it may
be desired to withdraw it. In order to enable this to be done a part of the shell
of the conical head toward the larger or rear end consists of plates overlapping at
their junction, and hinged at their forward ends to the fixed part of the head.
Toggle bars jointed at the rear ends of the plates, and a sliding sleeve pressed
forward or withdrawn by set screws working in a collar on the hollow shaft, are
convenient forms of apparatus by which the desired end may be accomplished, as
when the screws are turned backward the sleeve will be free to move and the edges
of the overlapping plates will be contracted.
The open throat or channel leading to the hollow shaft is constructed in two
parts, the upper having one end fastened to one of the plates of the boring head,
and its lower end sliding freely in the second section when the boring head is being
collapsed or expanded.
When boring tunnels of any considerable length the outside engine which drives
the excavator may also drive a suitable exhaust fan at the mouth of the shaft, the
ventilating pipes being made collapsable or telescopic for the purpose of extending
as the machine advances, the smoke and exhaust steam from the engine driving
the boring machine being conducted into said ventilating pipes..

page_text: A convenient method of bringing forward.sections of the lining or track is by
means of a tramway supported on one side of the bed plate of the machine.
A method of removing rock or other hard substances that may be encountered is
as follows:-
The boring machine is withdrawn from the heading, and strong circular bulk-
heads consisting of plates in the form of sections of a circle are binged to the lining
in order that the boring machine may be forced past them, but when closed they
are secured also by suitable side and back braces. An ordinary drilling machine
is then employed, the drill shafts of which pass through ball socket joints formed
in the bulkhead, in order that the loles may be drilled at any desired angle. The
drill shafts to the rock or other obstruction preferably pass through suitable tubes,
which remain in position after the drills have been withdrawn, in order that the
cartridges or charges may be pushed through them directly into the holes. This
arrangement of bulkheads protects the machinery from the effects of the explosion
or blasting, and also acts as an efficient check to water and mud in case these
should be encountered in large quantities.
For ordinary excavating on land or under water the apparatus undergoes but
slight modifications, being still formed with a rotary cutting face, hollow shaft,
screw conveyer bearings, and driving gear, as before described, the earth being
carried to the rear of the machine, and then delivered to.an elevator or other delivery
point.
"
A convenient method of delivering the excavated material I have found to be by
means of one or more hinged elevators supplied with endless chains and the
ordinary buckets which take the material as delivered by the screw conveyer. and
deposit it at the desired angle upon an overhead bank or other point of delivery.
A vibrating motion may be imparted to the machine, in order that it may cut a
groove in the earth of a greater width than the diameter of the cutting head.
For this purpose the bed plate of the machine is supported upon rollers which
rest on the lower bed plate which travels on the track.
Horizontal rollers are secured to the upper bed plate, and bear against the inside
of a ring secured to the lower bed plate, and having as a common centre a
supporting shaft, which maintains the relative positions of the two bed plates
horizontally, but permits the upper one to vibrate freely about the centre of the
supporting shaft. The oscillating motion is imparted to the upper bed plate, and
consequently to the cutting head by means of a crank pin, link, and gearing. The
side to side movement should be slow, as it is for the purpose of cutting a greater
width than the diameter of the cutting head, and at the same time leaving the
bottom of the cutting flat in cross section.
When using the excavating machine as a dredger it may be placed upon a boat,
and is operated in the ordinary manner, the only modification necessary being
the arrangement of parts, so that the cutting head may be raised or depressed,
depending upon the depth of the water or cutting to be made. In this arrange-
ment the hollow shaft has for its rear bearing a suitable collar having trunnions
turning freely in pillow blocks. A strong bracket projects from the collar, and
carries bearings for the screw conveyer shaft with its gears, all of which, as also
the further gear, being adapted to permit the cutting head to be raised or lowered
while at work. Although I have only described one cutting face as being employed
at a time, it is evident that two or more may be employed conjointly.
When using the apparatus for tunneling or excavating, the entire machine is
automatically pushed forward and kept to its work by means of a ratchet rail,
with which suitable gearing engages. When dredging or excavating from a boat
the forward motion may be imparted by means of ropes or chains secured at one
end to anchors ahead of the boat, the other ends of said ropes or chains after
passing over suitable pullies being wound upon winch drums.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Albert Livingstone Blackman in the Great Seal Patent Office on the
7th February 1882.
ALBERT LIVINGSTONE BLACKMAN, of the City of Nashville, State of Tennessee,
United States of America, but temporarily of Southampton Buildings, in the County!
of Middlesex, Gentleman. “ IMPROVEMENTS IN TUNNELLING AND EXCAVATING
APPARATUS.”
This Invention relates to the apparatus employed for tunneling or excavating
for railways, canals, or other works in which large quantities of sand, gravel, soil,
or other material have to be removed. The Invention consists of the arrangement
and combination of parts forming the apparatus hereinafter described, by which
tunneling or excavating may be rapidly, safely, and economically carried out. To
clearly explain the Invention and how the same may be practically carried into
effect, reference is made to the accompanying Drawings and letters of reference
marked thereon. Fig. 1 represents a side elevation, partially in section of a tunnel
boring machine in position for boring a cylindrical tunnel T in earth D, shewn in
vertical section. This form of machine is not intended for boring rock but is
adapted for earth wet or dry; A is a conical shaped boring head having a cutting
blade C, which is in connection with the hollow shaft B; A is supported by
arms, and hollow shaft B has bearings on the stands a, a', which rest on bed
plate C. A steam engine e secured to the bed plate C drives shaft el, having
pinion g' and gear wheel n fast upon it. A screw conveyor C¹ on shaft S extends
along the bore of the hollow shaft B, and has bearings 6111 in small end of boring
head, and also on stand a¹¹. When the boring head revolves in the direction of
the arrow (Fig. 3), the blade el will continue to cut or tear the earthy matter in
contact with it when the machine is forced ahead by the revolution of the feed
gear 81 (Fig. 3), meshing with the rack q on railway t, gear & being driven by
worm & on shaft e³, and worm gear 8 on counter shaft. The wheels o, o, having
bearings under the bed plate turn freely on track t as the machine is pushed along,
and support its entire weight. By means of the set screws, as shown, the machine
may be set to grade. The earth removed by the cutting blade is continuously
forced by the act of removal into the throat t', and along the channel d into the
hollow shaft B, from which it is continuously carried by the revolutions of the
screw conveyor C', and forced out of rear end of shaft B, where it falls. upon the.
chute u, seen in Fig. 10, with the end broken away. Conveyor C' is driven by
gear n on engine shaft e¹, meshing with gear m on shaft S, and may have a higher
speed of revolution than that of the boring head to ensure the rapid expulsion of
the soil cut away, and prevent clogging of the throat t¹ and channel d¹. The
operation of the machine as above described will bore a cylindrical hole of any
desired size, equal to that of the diameter of cutting head in any kind of earthy
deposit not too hard to resist the action of the cutter or cutters, and the material
cut away by the process will be rapidly removed from the hollow shaft and
deposited automatically at the rear end of the machine, thence to be carried
outside of the hole so bored, as hereinafter described. A hollow cylindrical
follower C (Figs. 1, 4, 8) of a diameter slightly less than that of the boring head
is provided for the purpose of resisting downward or lateral pressure of the earth
surrounding the bore, and holding it in place until the masonry or iron plate
lining of the tunnel is advanced to that point, it being intended that the operation
of lining the bore shall keep pace with that of boring, and that additions to the
extension of the lining shall always be made inside of the follower. Follower Cu
is drawn along by. the rollers 6¹¹ (Figs. 1 & 4) fixed on the end of boring head, and

page_text: bearing against flange d" of the follower, which by this means is drawn along with-
out revolving. The track supporting the machine rests on the lining of the tunnel,
as seen in Figs. 10, 11. & 12. The track is in short sections, which are successively
brought from the rear as the machine advances, and are laid down before it on the
lining, which in these Drawings is shown made of cast iron sections bolted together,
forming a continuous and rigid tube. A method of placing these cast iron sections
in position is shown in Figure 8, where an end view of follower 011 is represented
with several upper sections or plates bolted together inside the follower. The upper
plates are raised and held in position until bolted in the lining already finished by
means of levers k", ", fast on collar y¹¹ which revolves freely on eccentric yll,
which also revolves freely on hollow shaft B; a section or plate may be secured to end
of lever kl by passing pins through holes in the flange of such section and into
the ends of crossbar on the end of the lever k¹¹, Figs. 1 & 8. When the required
force is applied to freo the end of lever k" it will revolve collar y¹¹ until the other
end of said lever carries the plate to the required position for the roof or sides of
the tunnel lining. The eccentric y" is then turned about shaft B far enough to
thrust the plate against the inside of the follower and hold it in the desired
position until bolted to the sections already permanently in place. The method of
making a joint between the inside of the follower and outside of plate I to prevent
the passage of water between the two surfaces is shown in Fig. 9, where a part of
the boring head with the follower is shown in section; ¹¹ is a wide ring of rubber
or leather, or other suitable material secured to the inside of follower by screws or
rivets, and having part of its width free to press against the outside of plates I
when the flexible tubular ring all is expanded by internal pressure of air or water
against it. Ring 11 may be made of solid rubber, and its elasticity will cause it
to press the packing all and keep it tight. Ring all is retained in its place by a
groove in the follower, as shewn in the Drawing. The boring head being of a
diameter greater than that of the lining, it is necessary to so construct it that its
diameter may be reduced when obstructions to the forward progress of the machine
are encountered, or when from other causes it may be desired to draw it backward
through the tunnel. This is effected in the following manner:-A part of the
shell of the conical head A toward the larger or rear end, consists of plates of
shewn in the different views, Figs. 2, 3, 4, & 5, overlapping at their junction and
hinged at their forward ends to the fixed part of the head at h¹ (Figs. 1, 3, 5).
Toggle bars 61 jointed at the rear end of plates c¹ and also to the sliding sleeve l,
hold the several plates c' outward when sleeve is pressed forward by the screws (
working in collar n¹ fast on shaft B. When screws are turned backward, the
sleeve will be free to move backward also, and the edges of the plates c'
sliding freely by each other will allow the head to be contracted to the outlines,
shown by dotted lines in Figs. 1 & 2, and in full lines in Fig. 3. The shell of
follower C may be made in sections of convenient size held together by bolts, and
when the head is to be contracted the sections may be unbolted and contracted or
removed out of the way. Channel d' is constructed in two parts, the upper one dil
having its sides fastened to one of the plates c¹ and sliding or telescoping freely
on d when the boring head is being collapsed or expanded. The plates c¹ are
rigidly held together when the head is in the latter condition by bolts, as at e¹¹, Fig. 5.
Figs. 2, 3, 4, 5, & 6 are different views of the machine; Fig. 7 shews a curved
form of channel d³, presenting an easy entrance to the material removed by the
cutter; Fig. 10 shews section of a tunnel lined with cast iron plates I, ventilating
pipes P, P, P", connected with the exhaust fan G at the mouth of shaft R' and
with the boring machine by arm on stand a¹ for the purpose of extending
pipe P as the boring machine advances, P being lengthened as required by sections
coupled to its rear end introduced through rear end of the larger pipe P
permanently fixed in its position. The exhaust steam from engine e passes out by
pipe p', and the smoke from engine C passes into pipe P by means of pipe " and
is drawn out of the tunnel by exhauster G. Steam is furnished to the engine e by

page_text: pipe p from the boiler of the locomotive C attached to the rear end of the boring
machine bed. Rollers i, i, (Figs. 10 & 11) support pipe P, so that it may be freely
drawn forward; engine H drives exhauster G and elevator E; an endless rope g
passes around a sheave f¹ secured to the boring machine bed and around the two
guide sheaves f" about the sheave suspended by a rope over sheave it on top
of frame K, having at one end the heavy weight j for keeping an even tension on
the travelling rope g. When the machine advances g is lengthened as required.
Elevator E is of the ordinary construction; it takes the excavated earth dumped
by the buckets & into the receiver J and raises it to hopper F, from which it may
be delivered into cars, as at o². Buckets & receive their load from the chute u
(Figs. 10 & 12) and travel on rope g, which rapidly carries them to be emptied
at J, rope g being supported at intervals by the sheaves f fastened to the tunnel
lining, as shown in Fig. 12, which is a cross section of the tunnel and shews the
rear end of the machine; Fig. 12 also shews a method of carrying the lining
sections past the machine to the forward end of tunnel, one section being represented
as suspended from the tramway f¹ fastened to the bed of the machine; Fig. 11
shews the rear end of the machine with stands a¹ and a¹¹ removed and a tramway
supported on one side of bed plate C of the machine, which allows track sections
already passed over by the machine to be brought from the rear to be laid in front
with but little labour; Fig. 13 shews a method of removing rock which may
incidentally obstruct the advance of the boring machine. The boring machine
having been withdrawn from the heading of tunnel the strong circular bulkhead V,
consisting of plates in form of sections of a circle 2, Fig. 14, secured by strong
hinges h to the iron lining I of the tunnel, and further secured against external
pressure by the braces; 71 is used to prevent the entrance of water and mud, as
well as to shield the workmen and machinery from the effect of the explosives used
in blasting the rock to be removed; D' is a diamond drilling machine of the
ordinary construction resting upon the track t and adjustable to drill holes in
rock R at any required angle. The drill shafts w³ pass through the ball joints v
in bulkhead V, which arrangement allows this adjustment to be readily made, and
at the same time water, as at W, would be prevented from entering the tunnel in
the rear of the bulkhead while the rock R is being pierced with holes wll to receive
.the cartridges v¹. The tube wis used when a body of water or mud (Fig. 13)
intervenes between the rock and the bulkhead, the tube being passed through one
of the ball joints in the bulkhead and the outer end held against the rock after
the hole has been drilled. The drill shaft is then withdrawn, the tube remaining
in position until the cartridge has been pushed through it into the hole in the rock
with the wire w" attached to it. Tube w is then withdrawn and the cartridge
exploded. Wires wll leading from the cartridges may connect them with an
electric machine for the purpose of exploding them. When the operation of the
machine has been stopped and machine itself withdrawn from the heading if water
has been encountered the bulkhead V is secured in front of it in manner as
already described, the boring head A is contracted, and the machine is drawn
backward, the hinged plates of the bulkhead freely swinging to allow of its passage
(Figs. 15 & 16) to the rear, while when accomplished the plates of the bulkhead
are closed together and secured in place by the braces, the bulkhead presents
· an effectual barrier against water flooding the tunnel, as seen in Figs. 13 & 14.
Fig. 16 shows the contracted boring head having just passed the bulkhead to the
rear with the bulkhead plates closed and secured by braces vl. The plates s¹ can bo
swung either outward or inward, as seen in Fig. 16, their various positions being
shewn by dotted lines in order that the boring machine may pass the bulkhead either
forward or backward, as shewn by its different positions also in dotted lines;
Fig. 15 shows the bulkhead plates partially open with an end view of boring head
pressing them open as in the act of advancing or withdrawing through the bulk-
head; Fig. 32 shows cross sections of a cast iron lined double tunnel complete with
railway t. The method of joining the plates or sections I by flanges and bolts is

page_text: clearly shown in this and in Fig. 33, which is a view of a longitudinal section or
lining seen from the inside. When applying my Invention for open excavating or
from the surface of the water as is customary in dredgers, the same general principle
and form of apparatus is employed, the arrangements of parts being slightly
modified as hereinafter described; Fig. 17 shows a side elevation of the excavator,
the cutting head A being in section to show inside passages d leading to the
conveyor C in hollow shaft B. c, cl, are cutting blades firmly secured to face of
head A. When the engine e transmits motion to shaft B through the intervention
of pinion g² on shaft e¹ engaging with gear b on shaft B, the head will revolve, and
by the action of the feed pinion g' engaging "with the rack 9 secured to track t,
will be forced against the bank of earth D, when the projecting cutters will
rapidly cut away the earth in contact with them, and the earth so removed will be
forced through the throat t¹ into the passages d', and along the bore of the hollow
shaft B by the revolutions of the conveyor c¹. Pinion q¹ is driven by worm
gear on the upright shaft m², which in turn is driven by the worm a' on
shaft e¹¹. The operation of the machine as described will remove to the rear end
of the conveyer c¹ a body of earth from the bank D equal to the area of the
part of the face of cutting head in contact with it, multiplied by the distance
passed over by the machine in removing it. Friction rollers z, z, Figs. 17 and 21,
support the forward end of the conveyor shaft 8, allowing it to turn freely without
destructive abrasion by gritty particles. In order that the machine may cut a
groove in the earth of a width greater than the diameter of the cutting head
when required a vibratory motion from side to side may be given to the head as
shewn by the dotted lines (Fig. 18), and which is effected as follows:-The bed plate o
is supported upon the rollers y', which rest on the lower bed plate cll having the
wheels o bearing on the track t. Horizontal rollers y fast on frame c bearing
against the inside of the ring 7111 secured to the lower bed plate and having a
common centre on the shaft m' which maintains the relative positions of the two
bed plates horizontally, while permitting bed plate c to vibrate freely about the
centre of shaft m'; Fig. 19 shows a view of forward end of bed plates c, clll, with
the mechanisin for vibrating the same. On shaft ell worm s¹ near forward end
of the bed plates drives worm gear K having a slot, as seen in Figs. 18 and 19,
for the purpose of varying the stroke of the crank pin connected by link K' to
bedplate cat v™¸ As worm gear K revolves, the crank pin being connected to
the unyielding lower bed plate cli by the link K¹, will by its alternate pulling and
thrusting cause the bed plate c to oscillate from side to side on the rollers y'. The
vibration thus produced is intended to be very slow, and has for its object to cause
the machine to cut a width greater than the diameter of the head, and at the same
time leave the bottom of the cutting flat in its cross section for a width equal to
the sweep of the head from side to side, as seen at M, Fig. 26. Two bucket
elevators of the usual construction E¹, E¹, Figs. 22 & 23, supported by the frame K
on the rear end of bed plate c are driven by the gears x, x, from the pinion g" on
shaft e¹, and take the earth from the hopper and raise it to be deposited at the
required height, as in Figs, 26 and 27 at D¹ Either or both elevators may be
inclined at any convenient angle, as at E", Fig. 23. Figs. 24 and 25 show a
double excavating machine intended for shallow cuttings; Figs. 27 and 28 represent
a gang of excavators cutting a canal M and depositing the material D¹ along the
edges by means of the elevators E¹ and the belt conveyors C". The dotted line M,
Fig. 27, shows the bottom of the canal when the machines have taken a second
cut; Figs. 29, 30, & 31 show the excavating machine placed upon a boat or scow X
so as to be used for digging or dredging under water. The boat is anchored by
means of the cables 26 and the anchors 28, and warped or pulled ahead while the
machine is at work by the winches 14, around which the cables are passed. Said
winches are driven from the enginee through the intervention of the bevel gears 12,
13, & 23, and the shafts 24 & 25. If preferred spuds can be used to moor and
hold the scow up to the work while the machinery is at work instead of the

page_text: winches and cables. The boiler y supplies steam to the engine e.
The only parts
in these several views requiring special description are those relating to the
arrangement for raising and lowering the head A, so that it may operate at greater
or less distances from the surface of the water 31, as illustrated by the positions
of the head at A, or in the dotted lines at D. Shaft B has for its rear bearing the
collar 20 having trunnions 17 turning freely in the pillow blocks 18. A strong
bracket 19 projects from collar 20 carrying bearings for the shaft S with its gear 16,
and for a short shaft on which gears 10 & 15 are secured friction rollers & inter-
posed between the face of the collar 20 and the gear b fast on shaft B receive the
thrust of the head A when it is at. work. Gear 9 drives both shaft B through
gear b, and shaft S through gears 10, 15, & 16, its centre, coinciding with the centre
of the trunnions 17, therefore admits of the free vibration of shaft B about the
centre line of gear 9 and trunnions 17. Shaft B is supported at its outer end by
the journal box 32, which slides up and down between the curved guides O strongly
secured to the body of the boat. The geared segment 5 secured to the journal box
is moved up and down by the revolution of the pinion 4 in mesh with it, said
pinion being fast on a short shaft having bearings secured to the curved guides O, O,
and having the chain wheel 3 fast on one end. An endless chain 7 passes around
chain wheel 3, and also around the smaller chain wheel 8 fast on a short shaft
turning in bearings secured to the deck of the boat, and having ratchet wheel 22
and the drum 21 fast on it. The drum may be turned by a bar inserted in one
of the holes in its face, when movement will be given, the wheel 3 and pinion 4
thus operating the geared segment and raising or lowering the head A as desired,
the ratchet and pawl 22 holding the small chain wheel stationary at other times.
The head may also be raised and lowered by power from the engine.
Having thus described the nature of my Invention, and how the same may be
practically employed, what I claim and desire to secure by Letters Patent is,-
1st. In a tunneling or excavating apparatus the application and use of a rotary
hollow boring head made upon the general principles of a spiral augur or screw, as
and for the purposes set forth.
2nd. In a tunneling or excavating apparatus the combination of the rotary boring
head with hollow shaft and screw conveyor for carrying the excavated material
to the rear of the machine as described.
3rd. In a tunneling or excavating apparatus a rotary cutting head so arranged
as to admit of its diameter being increased or diminished without adding to or
removing any part of said head, substantially as specified.
4th. In a tunneling or excavating apparatus the combination with rotary boring
head of a non revolving follower, preferably drawn forward with and by the said
boring head, as and for the purposes set forth.
5th. In a tunneling or excavating apparatus the combination with the boring
head of the cutting blades with channel and throat, substantially as and for the
purposes set forth.
6th. In a tunneling or excavating apparatus the combination with boring head
of the feed mechanism for operating said head, substantially as described and set
forth.
7th. In a tunneling or excavating apparatus the combination with boring
machine of the mechanism for erecting and placing the lining, substantially as and
for the purposes set forth.
8th. In a tunneling or excavating apparatus the combination of the boring head
with a bulkhead composed of hinged plates as shewn, said bulkhead being secured
to the tunnel lining, as and for the purposes set forth.
9th. In a tunneling or excavating apparatus the combination of one or more
revolving heads (Figs. 24 & 25), and one or more hollow shafts and screw conveyors
with double bed plates and mechanism for imparting vibratory movement to the
upper bed plate, as shown and for the purposes described.
10th. In a tunneling or excavating apparatus the combination with boring head,

page_text: hollow shaft, and screw conveyor, of mechanism for imparting vertical motion to
said boring head and connected parts, as and for the purposes set forth.
In witness whereof, I, the said Albert Livingstone Blackman, have hereunto
set my hand and seal, this Thirtieth day of December, in the year of our
Lord One thousand eight hundred and eighty one.
Signed, sealed, and delivered
in the presence of
PHILIP M. JUSTICE,
14, Southampton Bdgs.,
Chancery Lane,
London.
ALBERT L. BLACKMAN. (L.S.)