IMPROVEMENTS IN AND RELATING TO MILLSTONES OR DISCS FOR GRINDING CORN AND SIMILAR MATERIALS
Year: 1884

page_text: I, HENRY HARRIS LAKE of the firm of Haseltine, Lake & Co, Patent Agents,
Southampton Buildings, London in the County of Middlesex, do hereby declare the
nature of said invention for "IMPROVEMENTS IN AND RELATING TO MILLSTONES OR
DISCS FOR GRINDING CORN AND SIMILAR MATERIALS" to be as follows:-
This invention relates to the stones and grinding discs used in mills for grinding
corn and similar materials.
In grinding corn or other grain it is important to prevent the same from passing
too rapidly between the grinding surfaces of the said stones or discs.
The natural formation of millstones tends to prevent the too rapid passage of the
grain as the said stones consist of a porous or rough material. Also with metallic
grinding discs, and particularly with those discs having furrows formed by high
ribs, this condition is partially fulfilled, as the said ribs offer a certain amount of
opposition to the passage of the corn or the like. The ribs, however, which
separate the grooves or furrows form a grinding surface. When the grain falls
from these ribs into the grooves or furrows it passes from between the grinding
surfaces much too rapidly.
The object of this invention is to prevent the corn or similar material from
passing too rapidly between the stones or discs.
In carrying the said invention into practice I provide the millstones or grinding
discs with a number of small teeth, transverse grooves, or the like, so that the grain
is retained for a sufficient length of time between the grinding surfaces. According
as it is desired to operate upon the husks of corn or other grains by grinding,
tearing, cutting or decorticating, the serrations on the grinding surface and in the
grooves are made sharp or blunt.
It is sometimes advantageous to dress some of the ribs or grinding surfaces in a
different manner from the others.
Owing to the different natures of the materials to be ground and also in order to
obtain the requisite quality of ground material, it is not only necessary that the
stones should be dressed differently but also that the serrations should be arranged
at different angles to each other.

page_text: •
An arrangement of grooves which is very advantageous is to place some of the
said grooves transversely and others angularly to the ribs so that the grain
is crushed in one groove and ground in another.
The surfaces of French millstones are so dressed, that the husks of the grain are
scarcely broken, which is due to the fact that the grain is not cut in the grooves
the section of which presents a right angle triangle, but is ground therein by
tearing and crushing: The hypothenuse of this triangle is level with the grinding
Burface. The direction in which the said millstones rotate is such that the deepest
parts of the grooves are in front so that the grain is crushed or ground between
two oblique surfaces.
The grinding surfaces are provided with main longitudinal grooves which are
preferably arranged as in French millstones in which are a number of sharp
metallic grooves of various depths forming a series of rows in close proximity.
The said grooves may be sharpened on one side only. In small stones angular
spaces must be formed in order to obtain a thorough filling up of the grooves; in
these spaces are formed transverse grooves as above described. In large millstones
the peripheries of which have a small curvature, the curve of the metallic grooves is
such that the angular spaces may be dispensed with.
By making the main grooves deep, a larger quantity of grain passes between the
stones than would otherwise be the case whereby a correspondingly increased
quantity of material is ground.
A great defect found in mill-stones revolving vertically is that the upper portion
of the revolving stone does not correspond exactly with that of the other stone
placed opposite thereto.
This defect according to the present invention is obviated by means of a wheel
which is adapted to guide or keep in place the revolving stone.
Dated this 1at day of February 1884
HASELTINE, LAKE & Co.,
For the Applicant.

page_text: I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co, Patent Agents,
Southampton Buildings, in the County of Middlesex do hereby declare the nature
of my invention for "IMPROVEMENTS IN AND RELATING TO MILLSTONES OR DISCS
FOR GRINDING CORN AND SIMILAR MATERIALS" and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement :—
This invention relates to discs for grinding corn or similar materials and
comprises the improvements hereinafter described.
These improvements are illustrated in the accompanying drawing the various
figures of which are hereinafter referred to.
One of the most important conditions in grinding generally, and especially in the
reducing operations by means of mills with discs or between discs, is to prevent the
grain from passing too rapidly between the grinding discs.
The natural formation of millstones tends to prevent this as they consist of a
porous, rough material. It is different, however, with metallic grinding discs, and
particularly with those the grinding surfaces of which are composed of single
metal strips placed on edge, the latter usually presenting a smooth surface. The
said strips, which project, form ribs and thereby offer a certain amount of resistance
to the movement of the grain between the discs. The intermediate pieces, however,
which separate and secure the strips in position and form the grinding surface do
not interfere with the passage of the grain.
It is over these intermediate pieces that the grain passes to the peripheries of the
discs. The speed with which the grain passes over these pieces may, according to
the amount of grinding required, be varied by providing the said intermediate
pieces with small teeth, transverse grooves, cutting edges or the like.
In Figure 8, a, b, c, d, indicate different forms of roughening for these intermediate
metallic portions.
According as a complete grinding, tearing, cutting or emptying of the husks
is required, the surfaces of the intermediate pieces receive one or other of these
forms.
It is sometimes advantageous, as for instance with the form c Figure 8, to
additionally roughen the surfaces either entirely or partially. The different natures
of the materials to be ground, and also the desired quality of the product, demand
not only a difference in the roughness generally, but also a great variation, in the
angle at which the transverse grooves or cutting edges are arranged to each
other as shewn at x, y and z, in Figure 1. The arrangement is often the most
advantageous, in which the several grooves differ both as regards form and angle,
so that the grain is cut in one groove and ground in the next.
The surface of a French millstone is so formed that, in the grinding operation,
the breaking of the husks is avoided as much as possible. This is due to the fact
that the grains are not cut but ground in the grooves, the transverse section of each
of which represents a right-angled triangle, the side 8, t of which corresponds to
the grinding surface in cross-section.
The direction in which the said millstones rotate is such that the deepest portion
of each groove is in front, so that the grain is smashed or ground between two
oblique surfaces as shewn in Figures 2 and 5. The grinding surfaces are provided
with longitudinal grooves which are formed by means of a pick.
These grooves, as well as the surfaces of the French millstones generally, are
accurately imitated in my improved grinding disc, in which a number of metal

page_text: strips, sharpened at the upper edges and having different heights, are placed side
by side in suitable succession and thus form the annular grinding surface of the
grinding disc. The said strips may be sharpened on one side only as shown in
Figures 6, 9 and 10.
In small discs, wedge-shaped intermediate pieces r are inserted in order to
provide a complete filling for the annular grinding surface. These wedge-shaped
pieces are roughened in the manner herein before described.
In a very large grinding disc the periphery of which has only a small curvature,
the curve of the metal strips can be such that the wedge-shaped intermediate pieces
may be dispensed with, in which case the section shewn in Figure 5 is obtained.
The graduations or differences in the heights of the various small strips can be
made greater towards the interior as shewn at v, win Figures 2 and 3, the grains
passing in this case with greater ease between the discs and being ground more
equally than otherwise.
A very great defect with mills having vertically revolving discs is that the work
done by the upper portions of the grinding discs is too small as compared with that
done by the lower portions.
This defect is considerably diminished by means of a throwing device provided
with a number of arms or vanes as shewn at L, Figures 1 and 7, which device is
connected to the revolving disc. The curve of the said arms or vanes is nearly the
same as that of the strips of the grinding discs.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
First. In grinding discs which are composed of small metal strips placed on edge,
roughening the surfaces of the intermediate pieces by forming therein transverse
grooves, teeth or the like.
Second. The imitation of the so-called French mill-stone by the arrangement of
small metal strips sharpened upon their edges and stepped in the direction of the
rotation of the discs.
CAL
1004