Improvements in Shields for use in Tunnelling.
Year: 1890

page_text: Date of Application, 12th May, 1890
Complete Specification Left, 12th Feb., 1891-Accepted, 14th Mar.,
1891
PROVISIONAL SPECIFICATION.
Improvements in Shields for use in Tunnelling.
I, JAMES JOHN NOBBS, of Park Crescent Mews, Crescent Road, Clapham, in
the County of London, Miner, do hereby declare the nature of this invention to be
as follows:-
My invention relates to shields for use in tunnelling, and has for its object to
provide a shield which can be more readily applied and used than shields as
heretofore constructed.
According to my invention the shield, instead of being arranged to be moved
forward bodily as the driving of the tunnel proceeds, is adapted to be moved
forward in sections and for this purpose the shield consists essentially of a series
of bars which are fitted to overlap each other at the edges so as to form a kind
of lagging. The said bars are supported internally by means of ribs formed in
sections so that they can be readily connected and placed in position. One of
the said ribs is formed with a series of cross-ribs to form a kind of lattice, each
opening of which is provided with a door for affording access to the different parts
of the face of the tunnel as required. The said bars are
adapted to be driven
forward independently of each other and in order to facilitate the operation each
of them may be provided with a screw lug against which the head of a hydraulic
ram may be caused to operate.
Dated the 12th day of May 1890.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Shields for use in Tunnelling.
1, JAMES JOHN NOBBS, of Park Crescent Mews, Crescent Road, Clapham, in
the County of London, Miner, do hereby declare the nature of this invention,
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:—
My invention relates to shields for use in tunnelling all kinds of strata, and has
for its object to provide a shield which can be more readily applied and which
affords greater safety than shields as heretofore constructed.
According to my invention the shield, instead of being arranged to be moved
forward bodily as the driving of the tunnel proceeds, is adapted to be moved
forward in sections, and for this purpose the shield consists essentially of a series
of steel bars or piles which are fitted to overlap each other at the edges so as to
form a kind of lagging, and which are supported internally by a sectional rib or
ribs or by frames closed at one end and provided with means for affording access to
the different parts of the strata to be tunnelled. The said bars or piles are adapted to
be driven forward independently of each other and, in order to facilitate the
operation, each of them is provided with a lug or stud against which the head
of a hydraulic ram or of an ordinary jack may be caused to operate.
To enable my invention to be fully understood I will describe the same with
reference to the accompanying drawings, in which :-
Figure 1 is a rear view of the shield constructed according to my invention:
Figure 2 is a horizontal section on the line a, Figure 1; and,
Figure 3 is a vertical longitudinal section on the line y y, Figure
1
:

page_text: Figure 4 represents a front view of the various sections of the rib or frame or
the shield slightly separated; and,
Figures 5 and 6 are views, drawn to a larger scale than the figures hereinbefore
described, of one of the piles:
Figure 7 is a sectional view on the line, Figure 6, and drawn to a larger
scale than the said Figures 5 and 6:
Figure 8 is a view similar to Figure 1 illustrating a modification of my
invention; and,
Figure 9 is a longitudinal vertical central section of the same.
", u indicate the piles of my improved shield, the edges of which are rabbeted or
grooved, as indicated most clearly in Figures 5, 6 and 7, so that they will rest one
upon the other, and cach of which, on the underside is provided with a dovetailed
groove a' and with a series of slots a², a², part of the length of each of which is
also of a dovetail shape to receive the dovetailed shank of a stud a³ for a purpose
hereinafter described; the forward end of each pile is also sharpened or bevelled,
as indicated in Figures 5 and 6, to enable it to be pushed through the strata.
b, c, d, e, f, and
are the sections of the rib upon which the said piles are
supported, which sections form parts of frames b', c', d', 'f, and g' respectively,
the said frames being of such shapes (for instance, as shewn most clearly in
Figure 4) that, when fitted together, as shewn in Figure 1, they will be in
contact with one another, and which are of such width that the interior of each
frame forms a chamber in which the workmen can operate. The front ends of
these frames are closed by plates h, and doors, h, and in the said plates and doors
are formed holes i, i closed by plugs, .. On the sections are keys 2, 2 which
engage the grooves a¹ of. the piles a, a. j, j are openings in the doors ', ' of
the frames ', e', which openings are closed by sliding doors j', j'. I sometimes
apply similar openings in the doors of the other frames. Between the frames ', ' and
the frame, and between the frames f', d'and the frame e' are plates k, which
can be operated in the manner hereinafter described, the said plates k, k being
rabbeted at their edges so as to more or less support one another.
The operation of the apparatus herein before described is as follows :-
Assume the same to have been fixed in position, as shewn in Figure 2, so
that the front of the shield is in close proximity to the material to be removed:
now the piles in contact with, say, the sections b, g, e are pushed forward by
means of hydraulic jacks acting against the studs a³, any obstructions, such as
stones, to the forward movement of the piles being pushed out of the way by
means of bars inserted through the holes i or j. The doors ', ' of the
frames, are then opened so that the material in front of the same can
be removed to the desired extent. The said frames are then pushed forward and
the same operation is repeated for the lower half of the shield, that is to say,
the piles are driven forward and the material then removed from the front of the
lower sections to allow the same to be moved forward. These operations are
repeated from time to time as the work proceeds.
When working in soft treacherous ground push forward the plates k, before
opening the doors h¹. so that the material in front of the frames, and f, d is
confined; and in cases where it would be dangerous to open the said doors, I
remove the material through the openings j, j to a sufficient extent to render the
-opening of the doors safe.
To enable the plates k, k to be pushed forward they are provided with slots
and studs similarly to the piles a, a.
The lower and upper cross-beams 2 and 2 of the frames and e¹ respectively
and the. floor of the frame ¹ are made removable so that, if required, more
room is obtained for operating in the said frames.
As the cutting of the tunnel proceeds brickwork is applied, as indicated; the
space around the brickwork, formerly occupied by the piles a, a, being filled
with grouting in a well known manner.

page_text: It will be obvious that this order of procedure, as regards the movement of
the various parts of the apparatus may be varied according to circumstances.
When working in safe ground sometimes support the piles upon a rib or
ribs, the sections of which or each of which are bolted together, so that the
said rib or ribs may be moved forward bodily, or if it is only necessary to
support the roof. I dispense with the side and bottom sections, and mount the
upper section upon a frame or carriage l, as shewn in Figures 8 and 9, which
carriage is adapted to run upon a movable platform m made in sections, the
section of the said platform over which the frame last passed being taken to
the front of the apparatus so that the frame, when moved forward, will again
run onto it.
In the apparatus first described and also in the modification thereof suitable
rollers are provided, for instance, as indicated in dotted lines by the letters n, n for
reducing, as much as possible, the friction between the various frames whilst
being moved.
The chief advantages of my invention, in addition to that of being enabled to
move forward the parts of the shield independently, are that no timber is
required to support the piles, and that the ribs or frames carrying the said
piles can be advanced without the necessity of temporarily supporting the said
piles.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that I make
no separate claim to the use of piles (sometimes called needles) as I am aware
that such piles are well known and have been in use for many years, but what
I claim is
1. A tunnelling shield having a series of piles mounted upon a sectional ring
or sectional ribs, the sections of which are so arranged that each one may be
moved forward independently of the others, substantially as described.
2. In a tunnelling shield having a series of piles as described, carrying the
said piles upon the supporting ring by means of dovetailed lugs or studs entering
corresponding grooves in the piles.
3. The improved tunnelling shield hereinbefore described and illustrated in the
accompanying drawings.
Dated the 12th day of February 1891
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.