IMPROVEMENTS IN ROCK-BORING APPARATUS
Year: 1881

page_text: LETTERS PATENT to Martin Macdermott, of 25 & 26, Pudding Lane, in
the City of London, Architect, and William Glover, of the Albert Iron
Works, Saint James' Road, Bermondsey, Engineer, for an Invention of
"IMPROVEMENTS IN ROCK-BORING APPARATUS.”
PROVISIONAL SPECIFICATION left by the said Martin Macdermott and
William Glover at the Office of the Commissioners of Patents on the 17th
September 1881,
MARTIN MACDERMOTT, of 25 & 26, Pudding Lane, in the City of London,
Architect, and WILLIAM GLOVER, of the Albert Iron Works, Saint James' Road,
Bermondsey, Engineer. "IMPROVEMENTS IN ROCK-BORING APPARATUS."
In the Specification of the Letters Patent granted to the said Martin Macdermott,
and dated 2nd of July 1877, No. 2542, and in the Specification of the Letters Patent
granted to the said Martin Macdermott and George William Elliott, and dated
28th June 1878, No. 2598, are described improved machines for boring in rock
by hand-power. Now in making these machines and in working them practically
we have discovered that by the alteration and modification of certain details
thereof great advantages may be gained, and these improvements and modifications
form the subject of our present Invention.
In the Specification dated 2nd July, A.D. 1877, No. 2542, above referred to, is
described a brake mechanism or arrangement contained within a cast-metal box
which we find it advantageous to modify in the following manner :-
Instead of a box suspended & attached to the standard of the apparatus and
consisting of about ten separate pieces, we have, suspended and attached in the
same way as therein described, a cast iron or other metal plate having on the
upper part thereof a tube which forms part of the same casting as the plate, and
through which tube the main screw of the machine is passed. To the back of
this plate is attached a small handle, the object of which will be hereafter explained.
Part of the cast plate consists of a hollow boss projecting from it at right angles.
On this boss we bang loosely a second piece, also of cast metal, which forms at

page_text: once a wheel gearing with the screw (already described as passing through a tube
at the top of the first piece), the cover of the brake and the cavity for receiving
the brake. This piece is formed as to its outer edge or periphery as a worm or
gearing wheel, and is made hollow at the back to receive a brake or expanding
ring or spring of metal, which brake ring is made to expand by means of a wedge
actuated by the small handle at the back already referred to. The external surface
of this wheel-casting has in the centre a tubular projection which serves to hang
it on the boss of the cast plate, and between the periphery and tubular projection
last described it carries four spurs, more or fewer, to afford leverage for a bar
used in withdrawing the screw. By this arrangement the number of pieces
used in the former arrangement (as described in the Specification of 2nd July
1877, No. 2542, for the same purpose) is reduced by about one-half.
The second part of our Invention refers to improvements and modifications
of apparatus described in the Specification already referred to, dated 28th June
1878, No. 2598, and more especially to the form and disposition of the cams
by means of which the blow is delivered by the machine. The cams therein
described and hitherto used are made so as to lift the opposing weight over
a convex surface, the load increasing as the radius of the cam becomes longer.
The "plate-cam" which forms the subject of this part of our Invention is so
devised that the weight is lifted along a concave surface towards the centre of its
own revolving axis and not from such centre as in former cams. The advantage
of the plate-cam over the old cam is that when it is acting against an increasing
'load, such as a spring in tension, the lift begins at the end of the cam or at its
longest radius, consequently when the tension or load is least, and as it revolves
the tension of the spring or the load increases while it is being drawn towards the
centre of the cam along a surface with continually diminishing radius until it is
released and the blow delivered. Another advantage is that more lifts can be
obtained in one revolution with the plate-cam than with the ordinary cam.

page_text: .
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Martin Macdermott and William Glover in the Great Seal Patent
Office on the 17th March 1882.
MARTIN MACDERMOTT, of Scott's Chambers, 25 & 26, Pudding Lane, in the
City of London, Architect, and WILLIAM GLOVER, of the Albert Iron Works,
St. James' Road, Bermondsey, London, S.E., Engineer. "IMPROVEMENTS IN ROCK-
BORING APPARATUS."
In the Specification of the Letters Patent granted to the said Martin Macdermott,
and dated 2nd July 1877, No. 2542, and in the Specification of the Letters Patent
granted to the said Martin Macdermott and George William Elliott, and dated
28th June 1878, No. 2598, are described certain improved machines for boring in
rock by hand power. Now in making these machines and in working them
practically we have discovered that by the alteration and modification of certain
parts and details thereof great advantages may be gained.
These improvements
and modifications form the subject of our present Invention.
In the Specification, dated 2nd July 1877, No. 2542, above referred to, is
described a brake arrangement or mechanism contained within a cast metal box
which we find it advantageous to modify in the following manner :-
Instead of a box suspended and attached to the standard of the apparatus and
consisting of about ten separate pieces, we have suspended and attached in the
same way as described in the Specification of the Patent last referred to, a cast
iron or other metal plate, as shewn at Figures I., II., & III. of the accompanying
Drawings, Figure I. being a front elevation; Figure II., a section of the same (with
the attached parts superadded); and Figure III., a side elevation. This plate has
on the upper part thereof a tube 1 which forms part of the same casting as the
plate, and through which tube the main screw of the machine is passed. To the
back of this plate is attached a small handle 2, Figure III., the object of which will
be hereafter explained. Part of this cast plate consists of a hollow boss 3 projecting
from it at right angles. On this boss we hang loosely a second piece, also of cast
metal, shewn in section at Figure II., and in elevation at Figure VI., and inarked 4,
which forms at once a wheel gearing with the screw (already described as passing
through a tube at the top of the first piece), the cover of the brake and the cavity
for receiving the brake. This casting is formed as to its outer edge or periphery
as a worm or gearing wheel 4ª, and is made hollow at the back to receive a brake
or expanding ring or spring of metal 5, which brake ring is made to expand by
means of a wedge actuated by the small handle 2, Figure III., at the back already
referred to, the wedge being driven in between the split or discontinuous ends of
the ring or spring, see Figures IV. and V., where front and side elevations 5 of this
brake ring are shewn with the wedge which serves to expand it 5 in position.
The external surface of this wheel-casting, see Figures II. and IV., has in the centre
a tubular projection 4b, which serves to hang it on the boss of the cast plate; and
between the periphery and the tubular projection last described it carries four
spurs or projections b, b¹, 61, 6111, Figures VI., the same being more or fewer, to
afford leverage for a bar used in withdrawing the screw, as shewn at Figure VI.
By the entire arrangement above described the number of pieces used in the
former arrangement for the same purpose as described in the Specification of the
2nd July 1877, No. 2542, is reduced by about one-half.
The second part of our Invention refers to improvements and modifications of
apparatus described in the Specification already referred to and dated 28th June
1878, No. 2598, and more especially to the form and disposition of the cams, by
means of which the blow is delivered by a machine employed to disintegrate stone

page_text: or mineral, &c. by impact, and to parts in connection therewith. The cams therein
described and those hitherto used for a like purpose are made so as to lift the
opposing weight over a convex surface, the load increasing as the radius of the
cam gets longer.
The "plate-cam" which forms the subject of this part of our Invention is shewn
at Figures VII. and VIII., and is so devised that in action the weight is lifted along
a concave surface towards the centre of its own revolving axis and not from such
centre as in the former cams. The advantage of the "plate-cams" over the old
cams is that when it is acting against an increasing load, such as a spring in
tension, the lift begins at the end of the cam or at its longest radius, consequently
when the tension or load is least, and as it revolves the tension of the spring
or the load increases while it is being drawn towards the centre of cam along a
surface with continually diminishing radius until it is released and the blow
delivered. Another advantage is that more lifts can be obtained with one revolution
on its axis by the "plate-cam" than with the ordinary cam.
Figure VII. is a front elevation of the improved "plate-cam" shewing three
projecting cams cast on the plate and marked 7, 71, 71, along the concave surfaces
of which the weight is lifted successively, it being understood that the number
of cams may be increased or diminished; Figure VIII. is a side elevation of the
same.
In witness whereof, we, the said Martin Macdermott and William Glover,
have hereunto set our hands and seals, this Fifteenth day of March, in the
year of our Lord One thousand eight hundred and eighty two.