IMPROVEMENTS IN APPARATUS FOR SPLITTING ROCKS AND OTHER MASSES
Year: 1869

page_text: LETTERS PATENT to Horace Lear Bolger, of 64, Arthur Road, Brixton,
in the County of Surrey, Engineer, and Joseph Meekin, of Milton
Road, Dulwich, in the County of Surrey, Tunnelling Engineer, for
the Invention of "IMPROVEMENTS IN APPARATUS FOR SPLITTING ROCKS
AND OTHER MASSES."
Sealed the 22nd December 1869, and dated the 1st October 1869.
PROVISIONAL SPECIFICATION left by the said Horace Lear Bolger
and Joseph Meekin at the Office of the Commissioners of Patents,.
with their Petition, on the 1st October 1869.
We, HORACE LEAR BOLGER, of 64, Arthur Road, Brixton, in the
County of Surrey, Engineer, and JOSEPH MEEKIN, of Milton Road,
Dulwich, in the County of Surrey, Tunnelling Engineer, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN APPARATUS FOR
SPLITTING ROCKS AND OTHER MASSES," to be as follows:-
Our Invention has for its object the construction of apparatus for the
purpose of splitting rock, coal, minerals, timber, and other masses of
material. For this purpose we drill, bore, jump, or otherwise pierce
a round hole in the mass to be split, and introduce into it the apparatus,

page_text: which we proceed to describe. This apparatus consists of a conical or
taper screw formed on a rod or mandril of steel, iron, or other suitable
material, and of a nut which is divided into two or more segments, also
of a cylindrical step with a pivot hole therein for receiving the point of
the conical screw or mandril. We introduce into the hole first the
pivot step, then the split nut, and into this we insert the small end of
the screwed mandril. We turn the mandril round by a wrench, ratchet,
or other convenient means and thus screw it into the split nut. Its
taper form causes the nut to expand as the screw advances, and the
expansion of the nut puts a splitting strain on the sides of the hole,
and this pressure causes the segments of the nut to be held firmly
within the hole, so that they cannot turn round or move longitudinally.
When the screw has so far advanced that its end bears against the
pivot step which prevents it from advancing farther, the screw being
still turned round tends to drag the nut forwards, but it being securely
held within the hole cannot move without drawing with it the mass of
material in front of it. Thus besides the tranverse splitting strain
caused by the expansion of the nut there is also a longitudinal dragging
strain tending to detach the mass into which the hole is pierced from
the mass behind.
We sometimes employ the apparatus without the step when the
bursting strain is sufficient for the purpose required.
Another form of our improved apparatus is the following:-We use
a cylindrical screwd mandril of equal diameter throughout fitted to a
solid nut, which is tapered on the outside, and which may be hexagonal,
square, or of any other polygonal form, so as to render it incapable of
turning round within a socket which surrounds it; this socket is
cylindrical outside, inside it is of a form adapted to the exterior of the
taper nut, and it is divided into two or more segments. In employing
this apparatus we first put into the hole a pivot step like that already
described; we then insert the screwed mandril with its nut and divided
socket, the small end of the nut being directed outwards. On turning
the screwed mandril, the end of which bears against the step, the nut is
drawn forwards or outwards, and on account of its taper form it expands
the divided socket enclosing it. Thus a bursting strain is produced,
which tends to split the mass, and at the same a dragging strain is
applied to it tending to detach the portion containing the hole from that
behind it

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Horace Lear Bolger and Joseph Meekin in the
Great Seal Patent Office on the 19th March 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, HORACE
LEAR BOLGER, of 64, Arthur Road, Brixton, in the County of Surrey,
Engineer, and JOSEPH MEEKIN, of Milton Road, Dulwich, in the County
of Surrey, Tunnelling Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of October, in the year of
our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto us, the said Horace Lear Bolger and Joseph Meekin,
Her special licence that we, the said Horace Lear Bolger and Joseph
Meekin, our executors, administrators, and assigns, or such others as we,
the said Horace Lear Bolger and Joseph Meekin, our executors, adminis-
trators, 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, 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 APPARATUS
FOR SPLITTING ROCKS AND OTHER MASSES," upon the condition (amongst
others) that we, the said Horace Lear Bolger and Joseph Meekin, our
executors or administrators, by an instrument in writing under our, 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 we, the said Horace Lear Bolger and Joseph
Meekin, do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
Our Invention has for its object the construction of apparatus for the
purpose of splitting rock, coal, minerals, timber, and other masses of
material. For this purpose we drill, bore, jump, or otherwise pierce a
round hole in the mass to be split, and introduce into it the apparatus,

page_text: which we proceed to describe. This apparatus consists of a conical or
taper screw formed on a rod or mandril of steel, iron, or other suitable
material, and of a nut which is divided into two or more segments,
also of a cylindrical step with a pivot hole therein for receiving the
point of the conical screw or mandril. We introduce into the hole
first the pivot step, then the split nut, and into this we insert the small
end of the screwed mandril. We turn the mandril round by a wrench,
ratchet, or other convenient means, and thus screw it into the split nut;
its taper form causes the nut to expand as the screw advances, and the
expansion of the nut puts a splitting strain on the sides of the hole,
and this pressure causes the segments of the nut to be held firmly
within the hole so that they cannot turn round or move longitudinally.
When the screw has so far advanced that its end bears against the pivot
step which prevents it from advancing farther, the screw being still
turned round tends to drag the nut forwards, but it being securely held
within the hole cannot move without drawing with it the mass of
material in front of it. Thus besides the transverse splitting strain
caused by the expansion of the nut there is also a longitudinal dragging
strain tending to detach the mass into which the hole is pierced from
the mass behind.
We sometimes employ the apparatus without the step when the
bursting strain is sufficient for the purpose required.
Another form of our improved apparatus is the following:-We use a
cylindrical screwed mandril of equal diameter throughout fitted to a
solid nut, which is tapered on the outside, and which may be hexagonal,
square, or any any other polygonal form, so as to render it incapable of
turning round within a socket which surrounds it. This socket is
cylindrical outside; inside it is of a form adapted to the exterior of the
taper nut, and it is divided into two or more segments. In employing
this apparatus we first put into the hole a pivot step like that already
described. We then insert the screwed mandril with its nut and
divided socket, the small end of the nut being directed outwards. On
turning the screwed mandril, the end of which bears against the step,
the nut is drawn forwards or outwards, and on account of its taper form
it expands the divided socket enclosing it. Thus a bursting strain is
produced which tends to split the mass, and at the same time a dragging
strain is applied to it tending to detach the portion containing the hole
from that behind it.

page_text: DESCRIPTION OF THE DRAWINGS.
Fig. 1 represents an apparatus constructed according to our Invention.
a is the mandril having a taper screw formed on it at one end; b is
the nut, which is made in two parts, as represented on a larger scale in
Fig. 2; c is the pivot step in which the pivot end of the screw a bears.
The taper screw as it advances into the divided nut expands it, as
indicated by the dotted lines, so as to put a splitting strain on the sides
of the hole and to cause the nut to be held firmly in the hole. The
continued turning of the screw after the pivot end has begun to bear
against the step throwing a forward strain on the nut causes it to detach
and drag with it a mass of the substance in front of it.
Fig. 3 represents another form of the apparatus. d is the mandril
screwed throughout part of its length but not tapered; e is the nut,
hexagonal, square, or of any other polygonal form, so as to render it
incapable of turning within the socket f. The nut is tapered outside,
and the socket is tapered inside and divided into two or more segments,
as represented on a larger scale in Fig. 4. g is the pivot step. When
the screwed mandril d is turned, its end resting in the pivot step g, the
nute is caused to advance within the socket f, and so to expand the
socket, which acts by side pressure and forward drag as the split nut in
Fig. 1.
Having thus described the nature of our Invention, and in what
manner the same is to be performed, we would have it understood
that we do not confine ourselves to the precise details or proportions
represented in the Drawings, as these may be varied to suit different
conditions in the masses to be acted on.
In witness whereof, I, the said Horace Lear Bolger, have hereunto
set my hand and seal, this Sixteenth day of March, in the year
of our Lord One thousand eight hundred and seventy.
(Witness),
GEORGE MESSENGER.
H. L. BOLGER. (L.s.)