IMPROVEMENTS IN CUTTING, BORING, GRINDING, AND PULVERIZING STONE AND OTHER HARD SUBSTANCES
Year: 1870

page_text: LETTERS PATENT to Alfred Vincent Newton, of the Office for Patents,
66, Chancery Lane, in the County of Middlesex, Mechanical
Draughtsman, for the Invention of "IMPROVEMENTS IN CUTTING, BORING,
GRINDING, AND PULVERIZING STONE AND OTHER HARD SUBSTANCES."-A com-
munication from abroad by Benjamin Chew Tilghman, of Phila-
PROVISIONAL SPECIFICATION left by the said Alfred Vincent Newton
at the Office of the Commissioners of Patents, with his Petition, on
the 3rd November 1870.
I, ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery
Lane, in the County of Middlesex, Mechanical Draughtsman, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN CUTTING,
BORING, GRINDING, AND PULVERIZING STONE AND OTHER HARD SUBSTANCES," to be
as follows:
In the Provisional Specification filed by me, August 1st 1870, No. 2147,
an Invention was described for cutting and grinding stone, metal, glass,

page_text: and other hard substances by means of a stream of sand driven rapidly
against them by a jet of steam, air, water, or other suitable gaseous or
liquid medium. Experiment has, however, shewn that in certain cases
the requisite velocity may conveniently be imparted to the sand by
other means.
3
Now the present Invention consists in cutting and grinding stone,
metal, glass, and other hard or solid substances by means of a stream of
sand to which the requisite velocity has been given by the direct appli-
cation of mechanical force, such as, for example, the blow or impact
of a solid body moving with sufficient velocity, or the centrifugal or
tangential force derived from rapid rotation, or the force of gravity
obtained by letting the sand fall from a sufficient height.
SPECIFICATION in pursuance of the conditions of the Letters Patent,.
filed by the said Alfred Vincent Newton in the Great Seal Patent
Office on the 3rd May 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Mechanical Draughtsman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Third day of November, in the year
of our Lord One thousand eight hundred and seventy, in the thirty-
fourth year, of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alfred Vincent Newton, Her
special licence that I, the said Alfred Vincent Newton, my executors,
administrators, and assigns, or such others as I, the said Alfred
Vincent Newton, 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, 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 CUTTING, BORING, GRINDING, AND PULVERIZING
STONE AND OTHER HARD SUBSTANCES," being a communication to me from
abroad by Benjamin Chew Tilghman, of Philadelphia, in the State of
Pennsylvania, United States of America, upon the condition (amongst

page_text: others) that I, the said Alfred Vincent Newton, my executors or adminis-
trators, 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 per-
formed, 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 Alfred Vincent Newton, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the Drawing hero-
unto annexed, and to the letters and figures marked thereon (that is to
say):
:-
In the Provisional Specification filed by me August First, One thou-
sand eight hundred and seventy, No. 2147, an Invention was described
for cutting and grinding stone, metal, glass, and other hard substances
by means of a stream of sand driven rapidly against such substances by
a jet of steam, air, water, or other suitable gaseous or liquid medium.
Now experience has proved that in certain cases the requisite velocity
may conveniently be imparted to the sand by other means than those
just indicated, and it is to the use of new means for attaining the desired
end that the present Invention relates.
The improvements consist in cutting, grinding, or engraving stone,
metal, glass, and other hard or solid substances by means of a stream of
sand used as a projectile to which the requisite velocity has been given
by the direct application of mechanical force, such as, for example, the
blow or impact of a solid body moving with sufficient velocity, or the
centrifugal or tangential force derived from rapid rotation, or the force
of gravity obtained by letting the sand fall from a sufficient height.
The following is a description of the means for carrying the Invention
into effect. A disc or drum of any convenient size and material having
at its circumference a number of blades or paddles is made to revolve
preferably on a vertical axis with suitable velocity. Streams of sand
are let fall so as to be struck by the blades, and are projected tangentially
outwards with a velocity proportionate to that of the disc or drum.
In the accompanying Drawing the diagram Fig. 1 illustrates this
arrangement of apparatus. A being a hopper containing the sand,

page_text: and B the rotating propeller. The objects to be ground are held or
moved in the path of the projected sand until sufficiently cut. If
the striking faces of the blades or paddles are covered with caoutchouc
the grains of sand will be less broken by the shock. By the term
sand in this Specification I mean small grains or particles of any hard
substance of any degree of fineness of which common quartz sand
is a type. The same applications of the projected sand to the cutting,
grinding, or engraving of stone, metal, glass, and other hard or solid
substances may be made as has been described in the final Specification
of my Patent No. 2147 above referred to. As the blow or impact
of sufficient velocity between the grains of sand and the object to be
cut is the efficient agent of cutting it is evident that the effect will
be produced if the object itself moving with sufficient velocity be
made to strike upon the grains of sand in a state of comparative
rest, or if part of the required velocity be given in opposite directions to
cach, but I generally prefer to give the velocity to the sand as being
more manageable and convenient. The requisite velocity may also be
imparted to the sand in a gradual manner by centrifugal force. One
method is to arrange a number of straight or curved tubes like the
spokes of a wheel, having small openings at their outer ends, while their
inner ends communicate with a tube in the centre supplying the sand.
The wheel being made to revolve with suitable speed the sand is projected
from the holes at the circumference with a proportionate velocity, and
the objects to be ground are held or moved in the path of the sand.
This arrangement is illustrated in the Drawing at Figures 2 and 3;
Fig. 2 being a side view, and Fig. 3 a cross section of the centrifugal
apparatus. A revolving hollow disc or flat hollow wheel with apertures at
its circumference and a supply of sand in the centre may be substituted
for the hollow spokes. A stream of sand let fall from a height through
the open air spreads out and scatters widely and acquires only a moderate
velocity which owing to the resistance of the air remains nearly constant
instead of increasing in proportion to the height traversed. It has been
found that if a stream of sand is let fall through a vertical tube of
'suitable diameter open at both ends the contained column of air is soon
set in rapid motion and the velocity of the sand continues to increase
in proportion to the height traversed. By means of a tube of sufficient
height the requisite velocity can thus be imparted to the sand to enable
it to cut or grind hard substances. If a stream of sand be made to fall
from a closc vessel through a close vertical tube of sufficient length open

page_text: at the bottom the air will gradually be driven out by the falling sand
and an approximate vacuum can be obtained. If a stream of sand be
made to fall through a vertical tube open to the air at the top and the
falling sand and air be received into a suitable close vessel below a jet
or current of compressed air can be obtained.
I would remark that it is not intended to limit the Invention to the
use of any precise arrangement of machinery or apparatus for imparting
the desired velocity to the sand by the application of mechanical force
as it will be evident to any engineer that these details may be greatly
varied.
Having now set forth the nature of the Invention of "Improvements
in Cutting, Boring, Grinding, and Pulverizing Stone and other Hard
Substances," as communicated to me from abroad by my foreign corre-
spondent, and explained the manner of carrying the same into effect,
I wish it to be understood that under the above in part recited Letters
Patent I claim, the cutting, grinding, and engraving stone, metal,
glass, and other hard or solid substances by sand used as a projectile to
which the requisite velocity has been given by the direct application of
mechanical force or by gravity as above explained.
In witness whereof, I, the said Alfred Vincent Newton, have here-
unto set my hand and seal, the Third day of May, in the year
of our Lord One thousand eight hundred and seventy-one.