IMPROVEMENTS IN GRINDING MILLS
Year: 1860

page_text: LETTERS PATENT to Thomas Neal, of Saint John Street, Smithfield, in
the County of Middlesex, Engineer and Machinist, for the Invention of
"IMPROVEMENTS IN GRINDING MILLS."
PROVISIONAL SPECIFICATION left by the said Thomas Neal at the
Office of the Commissioners of Patents, with his Petition, on the
29th October 1860.
I, THOMAS NEAL, of Saint John Street, Smithfield, in the County of Mid-
dlesex, Engineer and Machinist, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN GRINDING MILLS," to be as follows:-
These improvements relate to the manner of working the stones between
which the material or substance is ground.
In ordinary horizontal grinding stones the top stone revolves, that is to say,
is the runner, and the bottom one is fixed or at rest. My improvements
consist in making the bottom stone the runner, and the top one fixed. The
bottom stone is fixed to a suitable fixing, made of metal or other suitable
material, through the boss or thimble of which passes or slides freely the
upright shaft, which may be squared, keyed, or grooved, the boss or thimble
of the fixing being made accordingly. The boss or thimble of the fixing is

page_text: supported at its lower extremity by a bearing in which it revolves, and, by
means of screws, levers, and other suitable contrivances in connection there-
with, the bottom stone may be thrust or forced with any desired pressure
against the top or fixed one, according to what the nature or peculiarity of the
substance or material to be ground may require.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Neal, in the Great Seal Patent Office on the 29th
April 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
NEAL, of Saint John Street, Smithfield, in the County of Middlesex, Engineer
and Machinist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of October, in the year of our
Lord. One thousand eight hundred and sixty, in the twenty-fourth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Thomas Neal, Her special licence that I, the said Thomas Neal,
my executors, administrators, and assigns, or such others as I, the said
Thomas Neal, 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 GRINDING MILLS," upon the condition (amongst others) that I, the said
Thomas Neal, 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 Thomas Neal, do hereby.declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly, described, and ascertained in and by the following
statement.:-
These improvements relate to the manner of working the stones between
which the material or substance, is ground.
In ordinary horizontal grinding stones the top stone revolves, that is to say,

page_text: is the runner, and the bottom one is fixed or at rest. My improvements
consist in making the bottom stone the runner, and the top one fixed. The
bottom stone is held in a suitable fixing or cast-iron pan, through the centre
of the boss or thimble of which passes or slides freely the upright shaft, which
drives or causes the said stone to revolve. The part of the shaft passing
through the thimble may be squared, keyed, or grooved, the boss or thimble
of the fixing or cast-iron pan being made accordingly. The boss or thimble
of the fixing may be supported at its lower extremity by a bearing in which
it revolves, and by means of screws, levers, and other suitable contrivances in
connection therewith. The bottom stone may be thrust or forced with any
desired pressure against the top or fixed one, according to what the nature or
peculiarity of the substance or material to be ground may require; or a
fixing or cast-iron pan carrying the bottom stone may be fixed on the upright
shaft, in which case, to allow the rising and falling of the said shaft, the usual
bevel wheel thereon is held by the framework of the mill, and the part of the
shaft passing through the eye of the said wheel is made as in the other case
when passing through the centre of the boss or thimble of the fixing or cast-
iron pan, as herein-before described.
And that the Invention may be fully understood I will proceed to describe
the Sheet of Drawings hereunto annexed, and forming part of this Speci-
fication, in which Fig. 1' represents a side elevation; Fig. 2 is a front elevation
of the same; Fig. 3, a longitudinal section through the line X, Y, in Fig. 4';
and Fig. 4, a plan of a stone-grinding mill constructed according to my
Invention. In each of the above Figures the same letters of reference indicate
like
parts.
:
A is the tap and fixed stone, which is held by a cast-iron frame or pan W,
in which it is fixed by wedges. The frame or pan W rests upon and is bolted
to four cast-iron columns N, N1, N2, N3, which are bolted to the foundation
plate P. The bottom stone or runner C is securely held by wedges driven
between its outer circumference and the inside of the fixing or cast-iron pan B,
and is fixed on the upright shaft E by key and bolt, and receives a rotatory
motion from the bevel wheels D and E. K, K', are the fast-and-loose pulleys,
carried by a shaft Z. When the driving strap or belt is thrown on the fast
pulley, motion is imparted to the mill through the bevel wheels D and 'E,
which impart a rotatory motion to the 'bottom stone C. The upright shaft F
is supported at its lower extremity by a footstep or gun metal bearing G,
which slides freely in the fixing J, bolted to the foundation plate P. The
said footstep or bearing G (and consequently the upright shaft F and bottom
stone C) is raised or lowered by turning the hand wheel H to the right or left

page_text: accordingly. A screw I is fixed to said hand wheel, which presses against. the
.bottom of the footstep or bearing, G. On turning up the screw I, the shaft
and bottom stone are raised, and on drawing the screw back it falls as the
weight of the shaft and stone bring it back. This movement is to permit the
adjustment of the stones so that a proper distance may be between them for
grinding any material according to its nature and requirements, or for
grinding coarse or fine. When once the proper distance is decided upon; the
set screw Q is tightened against the footstep or bearing G, to prevent its
further movement. The rising or falling of the shaft F does not disturb the
position of the bevel wheel D, which has no other motion but that of a
rotatory motion. This is accomplished in the following manner:-The boss R
of this bevel wheel D is made sufficiently long to form a neck S with a collar
at the upper extremity, which revolves between gun-metal steps fixed in the
framework M of the mill. The part of the shaft which passes through the
eye of the boss R slides freely therein, and is provided with or has fixed on
it a key or keys which slide in a groove or grooves cut in the eye of the
said boss; thus the wheel D transmits a rotatory motion to the upright shaft
F, and yet permits it to rise and fall independently.
The funnel or hopper L is to hold the material to be ground, which passes
thence into the eye U of the top and fixed stone, whence it is gradually
drawn in between the stones and ground. As the unground material rests
upon the runner C, which has rotary motion, it acquires a centrifugal force,
which tends to draw it between and through the stones, and thus keep up an
equal and regular supply of material. As the material is discharged at the
outer circumference of the stones, it may be taken off by a scraper T, which
rests against and rises and falls with the bottom stone. The shoot T is bolted
to the fixing which holds the top stone, and serves as a stay and guide for the
scraper. This arrangement dispenses with the tub which is used in ordinary
mills for grinding certain materials of a pasty nature, such as printing ink,
white lead, and divers colors. When grinding dry materials a tub or pan,
which fits closely round the pan carrying the bottom stone, is used to prevent
the dust flying about, and inside the tub is a brush which takes off the ground
material, and directs it to the shoot T. By using the cast-iron pan B to
hold the stone, no strain is put on the stone but that necessary to grind
the material; the stones may therefore be used when much thinner than by the
ordinary means.
Having now described and ascertained the nature of the said Invention,
and the manner of carrying the same into practical effect, I would have it
understood that I do not confine myself to the precise details herein

page_text: described and shewn, as the same may be departed from without altering
the nature of my Invention, but what I do claim is,-
Firstly, the mode of constructing the pan or fixing for holding and securing
the stones, as herein-before described and shewn.
Secondly, the general arrangement and construction of stone-grinding mills,
substantially as herein-before described.
In witness whereof, I, the said Thomas Neal, have hereunto set my
band and seal, this Twenty-ninth day of April, in the year of our Lord
One thousand eight hundred and sixty-one.
Witness,
JOSEPH WILLCOCK,
Patent Agent,
89, Chancery Lane,
London.
(L.S.) THOMAS NEAL.