IMPROVEMENTS IN MACHINERY EMPLOYED IN FORMING TUNNELS AND GALLERIES IN ROCKS
Year: 1868

page_text: LETTERS PATENT to Herbert Newton Penrice, of Witton House, near
Norwich, for the Invention of "IMPROVEMENTS IN MACHINERY
EMPLOYED IN FORMING TUNNELS AND GALLERIES IN ROCKS."
Sealed the 21st July 1868, and dated the 8th May 1868.
PROVISIONAL SPECIFICATION left by the said Herbert Newton:
Penrice at the Office of the Commissioners of Patents, with his
Petition, on the 8th May 1868.
I, HERBERT NEWTON PENRICE, of Witton House, near Norwich, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN.
MACHINERY EMPLOYED IN FORMING TUNNELS AND GALLERIES IN ROCKS," to be
as follows:-
This Invention has for its object improvements in tunnelling
machines.
For tunnelling in rock or hard. material I employ a head or frame
of nearly the same diameter as the tunnel to be produced and armed

page_text: IDIS nead is by compressed an working in a
cylinder or otherwise caused to move to and from the working face
striking it at each stroke, and the head or frame being slowly rotated
during the operation a circular tunnel or hole is gradually chipped
away.
So far the arrangement is not new, but my present Invention consists
in the peculiar construction of this head and its cutting teeth. In
place of making the head or frame with numerous arms each carrying
but a comparatively small length of cutting edge the head or frame is
now formed as a strong disc of east metal which is divided into four or
other number of broad arms with radial sides by a corresponding
numbers of spaces being left in it of sufficient size for a workman to
pass from one side of the disc to the other when it is in the tunnel. On
the face of the disc are a number of broad concentric grooves the
sides of which are somewhat undercut; into each such groove a number
of cutters are fitted so as to present concentric rings of V form cutting
edge. Each cutter consists of a short bar of steel suitably curved and
ground away to the required bevil on one edge. Some of the cutting
rings are ground on the convex side others on the concave.
In setting
the rings of cutters into their places in one of the grooves in the disc,
one ring is arranged around the outer side of the groove or that which
is the further from the centre of the disc, and another ring is arranged
around the inner side of the groove; these rings have their cutting
edges turned outwards or away the one from the other, and the cutters
are tapered or inclined on the side which is in contact with the side of
the groove to correspond to the undercut of the side. Two rings of
cutters being thus arranged the other two rings are
groove, one in contact with each of the rings first arranged and with its
cutting edge turned away from it; 'there is now a space left in the
centre of the groove, it 'tapers inwards from the cutting edges to the
bottom of the groove, the cutters last placed being inclined on the 'faces
which are opposite the one to the other; into this taper space a ring
wedge made up in sections like the cutters is introduced; these sections
are furnished with screw stems passing through the disc from the bottom
of the groove and receiving screw nuts beyond. At the outer circum-
ference of the disc 'there is an additional cutting ring edge, the outer
cutter in the exterior groove being made with two concentric cutting
placed in the

page_text: edges, the outer one projecting beyond the edge of the disc so as to clear
a way for it. In the centre of the disc is a chisel-like cutter with a cross
form cutting edge, and next to this is a ring cutter which may be made in
one piece outside this again. The cutters are arranged and held in the
manner already described, except that here close into the centre of the
disc the cutting rings and the ring wedge are complete, and the stems of
the sections of the ring wedge are held by cotters in place of by screw
nuts which here could not readily be applied. Each cutting ring in
passing from the centre to the circumference is set back so that the end
or working face of the tunnel or hole is always a conical hollow, thus
increased facility is afforded to the material to break away between the
ring grooves produced by the cutters.
In this arrangement it will be seen that the length of edge which
produces each groove is proportional or nearly so to the length of the
groove, so that every part of the edge has as nearly as possible the same
amount of work thrown upon it, and the cutting edges of each ring are
practically continuous from side to side of the broad arms or portions
of the disc.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Herbert Newton Penrice in the Great Seal Patent
Office on the 7th November 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HERBERT
NEWTON PENRICE, of Witton House, near Norwich, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighth day of May, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Herbert Newton Penrice, Her special
licence that I, the said Herbert Newton Penrice, my executors, adminis
trators, and assigns, or such others as I, the said Herbert Newton
Penrice, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter.
during the term therein expressed, should and lawfully might make,

page_text: use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN MACHINERY EMPLOYED IN FORMING TUNNELS AND GALLERIES
IN ROCKS," upon the condition (amongst others) that I, the said Herbert
Newton Penrice, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent. Office within six calendar
months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said Herbert Newton Penrice, do
hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement thereof, that is to say :-
This Invention has for its object improvements in tunnelling
machines.
For tunnelling in rock or hard material I employ a head or frame
of nearly the same diameter as the tunnel to be produced and armed
with cutting edges. This head is by compressed air working in a
cylinder or otherwise caused to move to and from the working face
striking it at each stroke, and the head or frame being slowly rotated
during the operation a circular tunnel or hole is gradually chipped
away.
So far the arrangement is not new, but my present Invention
consists in the peculiar construction of this head and its cutting teeth.
In place of making the head or frame with numerous arms each
carrying but a comparatively small length of cutting edge, the head
or frame is now formed of a strong disc of cast metal which is divided
into four or other number of broad arms with radial sides by a corres-
ponding number of spaces being left in it of sufficient size for a work-
man to pass from one side of the disc to the other, when it is in the
'tunnel. On the face of the disc are a number of broad concentric grooves,
'the sides of which are somewhat undercut. Into each such groove a
number of cutters are fitted so as to present four concentric rings of
V form cutting edge. Each cutter consists of a short bar of steel
suitably curved and ground away to the required bevil on one edge.

page_text: Some of the cutting rings are ground on the convex side others on
the concave. In setting the rings of cutters into their places in one
of the grooves in the disc, one ring is arranged around the outer side
of the groove or that which is the further from the centre of the disc,
and another ring is arranged around the inner side of the groove,
these rings having their cutting edges turned outwards or away the
one from the other, and the cutters are tapered or inclined on the
side which is in contact with the side of the groove to correspond to
the undercut of the side. Two rings of cutters being thus arranged,
the other two rings are placed in the groove, one in contact with
cach of the rings first arranged and with its cutting edge turned
away from it. There is now a space left in the centre of the groove;
it tapers inwards from the cutting edges to the bottom of the groove,
the cutters last placed being inclined on the faces which are opposite
the one to the other. Into this taper space a ring wedge made up
in sections like the cutters is introduced; these sections are furnished
with screw stems passing through the disc from the bottom of the
groove and receiving screw nuts beyond. At the outer circumference
of the disc there is an additional cutting ring edge, the outer cutter
in the exterior groove being made with two concentric cutting edges
the outer one projecting beyond the edge of the disc so as to clear a
way for it. In the centre of the disc is a chisel-like cutter with a
cross form cutting edge, and next to this is a ring cutter which may
be made in one piece outside this again. The cutters are arranged and
held in the manner already described, except that here close into the
centre of the disc the cutting rings and the ring wedge are complete
and the stems of the sections of the ring wedge are held by cotters
in place of by screw nuts which here could not readily be applied.
Each cutting ring in passing from the centre to the circumference is set
back so that the end or working face of the tunnel or hole is always a
conical hollow; thus increased facility is afforded to the material to
break away between the ring grooves produced by the cutters.
In this arrangement it will be seen that the length of edge which
produces cach groove is proportional or nearly so to the length of
the groove, so that every part of the edge has as nearly as possible
the same amount of work thrown upon it, and the cutting edges of
cach ring are practically continuous from side to side of the broad
arms or portions of the disc.

page_text: The annexed Drawing shows the cutter head or frame of a tunnelling
machine thus constructed. The machine itself may be essentially a
cylinder mounted horizontally on wheels and a sleigh and containing
a piston worked to and fro by compressed air or steam and at the
same time slowly rotated, the piston rod and cutter head being cast
in one picce.
The machine is also provided with suitable apparatus for feeding it
up to the working face as the rock is broken down. Such machines
are now well known as they have been previously used by me.
'
Figure 1 is a front view and Figure 2 is a transverse section of the
head or cutter frame which forms the subject of my present Patent.
a, a, is a massive disc cast by preference in bronze or steel in one
piece with a piston rod of great strength; a¹, a', are eccentric grooves
formed in it with undercut sides; b, b, are the segments of cutting
rings arranged in these grooves; c are the wedges by which they are
retained with their screw stems c¹ and nuts c, and these nuts are
locked by screws having conical heads which enter into conical
notches in the edges of the nuts when such screws are screwed in
as is also shewn in Figure 3; 6' is the outermost cutting ring, which
is double edged; d is the cutter to bore the central hole; e, the ring
cutter surrounding it, and which is one piece; 62 are the segments
of cutting rings arranged around it so as to form complete rings; care
the segments of the ring wedge which hold them, the stems of the
wedges are drawn up by a cotter c³. Where the cutting rings are
not complete but divided by the spaces in the disc the cutting edges
on the leading edge of each arm should stand out a slightly less
distance from the face of the disc than on the following side, so that
the leading corners may not be exposed to undue wear.
Having thus described the nature of my said Invention and the
manner of performing the same, I would have it understood that what
I claim is, the constructing machinery for tunnelling and forming
galleries in rocks with a working head having broad radial arms
receiving cutters presenting concentric rings of cutting edges and so
arranged that the length of cutting edge in each ring is proportional
or nearly so to the length of the circular groove which the edge
produces.

page_text: I also claim the constructing machinery for tunnelling and forming
galleries in rocks with a working head arranged substantially as above
described.
In witness whereof, I, the said Herbert Newton Penrice, have
hereunto set my hand and seal, this Fourth day of November,
in the year of our Lord One thousand eight hundred and sixty-
eight.