IMPROVEMENTS IN TUNNELLING MACHINERY
Year: 1881

page_text: LETTERS PATENT to Thomas English, of Hawley, near Dartford, in the
County of Kent, for an Invention of "IMPROVEMENTS IN TUNNELLING
MACHINERY."
PROVISIONAL SPECIFICATION left by the said Thomas English at the
Office of the Commissioners of Patents on the 5th December 1881.
THOMAS ENGLISH, of Hawley, near Dartford, in the County of Kent.
“IMPROVEMENTS IN TUNNELLING MACHINERY."
In the Specification to Letters Patent granted to me on the 25th October 1880,
No. 4347, 1 described tunnelling machinery in which a revolving boring head
mounted on a double framing is advanced along with the upper framing, and when
it has made a certain advance, it, with the upper framing, is held stationary while
the lower framing is advanced a corresponding distance, so that the tunnel is thus
bored step by step onwards. In employing machinery of this kind for boring a
large tunnel I find it advantageous to bore in the first place a heading of only
such moderate size as will admit conveniently the machinery and the workmen
attending it, and to enlarge the tunnel behind the machinery as the heading
advances. For this purpose according to my present Invention I invert the
machine, that is to say, turn it end for end and fix on its shaft a larger boring
head with tools capable of cutting the annulus of material extending beyond the
bore for the first heading. When two machines are employed in the same tunnel,
the first is kept at work cutting the heading at sonic distance in front of the
second, which enlarges the tunnel by cutting out the annulus. In order in this
case to provide for removal of debris from the front machine without interfering
with the action of the binder machine, I arrange in the framing of the latter a
continuously travelling chain of buckets, which receiving the debris made by the
front machine deliver it into the enlarged tunnel at the larger boring head, from
which place it can be removed by trucks or otherwise. In order to avoid inter-
ference of the hinder boring head with the pipe which conveys the compressed
0.1....מ

page_text: air to work the machinery of this head as well as that in front of it, I connect the
air supply pipe to a swivel union at the centre of the large boring head, and from
this union I make a communication either by boring the shaft or by carrying a
bent pipe past the boss of the boring head to a hollow stationary sleeve fitted with
stuffing boxes on the revolving shaft, from which sleeve the air is conducted by
pipes to the engines that work either or both machines. In some cases instead of
employing two separate machines, as above described, I mount both boring heads
on one framing fitting the bore of the smaller heading, the smaller head being in
front of the framing and the larger head behind it.
When this arrangement is adopted it is preferred to drive the two heads in
opposite directions so as to reduce the liability of the machine to turn round within
the heading.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas English in the Great Seal Patent Office on the 3rd June
1882.
16
THOMAS ENGLISH, of Hawley, near Dartford, in the County of Kent.
'IMPROVEMENTS IN TUNNELLING MACHINERY."
In the Specification to my Patent dated the 25th October 1880, No. 4347,
I described tunnelling machinery in which a revolving boring head mounted on a
double framing is advanced along with the upper framing, and when it has made
n certain advance, it, with the upper framing, is held stationary while the lowor
framing is advanced a corresponding distance, so that the tunnel is thus bored stop
by step onwards. In employing machinery of this kind for boring a large tunnel
I find it advantageous to bore in the first place a heading of only such moderate
size as will admit conveniently the machinery and the workmen attending it, and
to enlarge the tunnel behind the machinery as the heading advances. For this
purpose, according to my present Invention, I invert the machine, that is to say,
turn it end for end and fix on its shaft a larger boring head with tools capable of
cutting the annulus of material extending beyond the bore for the first heading.
When two machines are employed in the same tunnel, the first is kept at work
cutting the heading at some distance in front of the second which enlarges the
tunnel by cutting out the annulus. In order in this case to provide for removal
of debris from the front machine without interfering with the action of the hinder
machine, I arrange in the framing of the latter a continuously travelling chain of
buckets, which receiving the debris made by the front machine deliver it into the
enlarged tunnel at the larger boring head, from which place it can be removed by
trucks or otherwise.
In order to avoid interference of the hinder boring head with the pipe which
conveys the compressed air to work the machinery of this head as well as that in
front of it, I connect the air supply pipe to a swivel union at the centre of the
large boring head, and from this union I make a communication either by boring
the shaft or by carrying a bent pipe past the boss of the boring head to a hollow
stationary sleeve fitted with stuffing boxes on the revolving shaft, from which
sleeve the air is conducted by pipes to the engines that work either or both
machines.
Fig. 1 of the accompanying Drawings represents a longitudinal section of part
of a tunnel, Fig. 2 represents a transverse section, and Fig. 3 a plan shewing the
boring machine according to my Invention applied to enlarge the bore of the
tunnel from the smaller diameter A to the larger diameter B. The bore A having
been previously effected by the machine working with a head of smaller diameter,
as described in my previous Specification above referred to, a similar machine
inverted as shewn in the Drawings and provided with a large boring head C is
fixed in the bore already made, and its head C bores out the annular material
surrounding the smaller bore. As the smaller boring machine is at work in the
smaller part of the tunnel beyond A, I provide for supplying the compressed air to
work it and for removing the debris of its boring as follows:-On each side of the
central boss of the large boring head I fit an air chamber D and E communicating
by passages F through the boss. The pipe G which supplies compressed air enters
the revolving chamber D through a stuffing box, and the chainber E, which is
stationary, is fitted in a stuffing box attached to the revolving boss of C. From
the chamber E two pipes H and I lead backwards, the one pipe H conveying air
to work the adjacent machine, and the other pipe I being continued along the

page_text: tunnel to supply the machine which effects the smaller boro beyond A. The debris
from the front or farther advanced machine is brought back from it by trucks or
otherwise and discharged upon a shelf K which projects beyond the end of the
rear machine, and buckets L on a continuously travelling chain receive the material
and convey it back under the machine, finally delivering it on to a shoot M, along
which it descends, being caused by the revolution of the arms C to fall into the
enlarged part of the tunnel, whence it can be removed.
Having thus described the nature of my Invention, and in what manner tho
same is to be performed, I claim as improvements on tunnelling machinery, anch as
is described in the Specification to my Patent of the 25 October 1880, No. 4347,
above referred to,-
First. In combination with an enlarged boring head, the pipes G, H, and I, and
the communicating air chambers D and E, arranged and operating substantially as
and for the purpose set forth.
Second. In combination with the tunnelling machine in its inverted position,
the shelf K and the travelling chain of buckets L, substantially as and for the
purpose set forth.
In witness whercof, I, the 'said Thomas English, have hereunto set my hand
and seal, this Thirty-first day of May, in the year of our Lord One
thousand eight hundred and eighty two.