IMPROVEMENTS IN MILLS FOR CRUSHING, SPLITTING, AND GRINDING VEGE- TABLE AND MINERAL SUBSTANCES
Year: 1875

page_text: LETTERS PATENT to Samuel Corbett, of Wellington, in the County
of Salop, Agricultural Implement Manufacturer, for the Invention
of "IMPROVEMENTS IN MILLS FOR CRUSHING, SPLITTING, AND GRINDING VEGE-
TABLE AND MINERAL SUBSTANCES."
Sealed the 5th May 1876, and dated the 30th November 1875.
PROVISIONAL SPECIFICATION left by the said Samuel Corbett at the
Office of the Commissioners of Patents, with his Petition, on the
30th November 1875.
I, SAMUEL CORBETT, of Wellington, in the County of Salop, Agri-
cultural Implement Manufacturer, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN MILLS FOR CRUSHING, SPLITTING, AND
GRINDING VEGETABLE AND MINERAL SUBSTANCES," to be as follows:-
My Invention consists of the improvements herein-after described
in mills for crushing, splitting, and grinding vegetable and mineral
substances.
My Invention relates, first, to an improved construction of the
grinding or cutting faces or surfaces of the mill, and to the means for

page_text: conveying the substances to be crushed, split, or ground to the said
grinding or cutting faces or surfaces.
According to my Invention I form the grinding surfaces of the mill
of two flat discs of chilled cast iron, or white metal, or other hard metal
or alloy, between which surfaces the matter to be ground is fed. Instead
of feeding the substance to be ground through the centre or eye of the
cutting or grinding plates or discs as usual, I feed the said substance
through the back of the fixed cutting or grinding plate and frame of the
mill on one side of the said mill by means of rectangular openings made
in the said cutting or grinding plate and back, the said openings being
situated about midway between the centre and the circumference of the
said plates. By this arrangement the material to be ground is fed to the
grinding surfaces of the mill at those parts of the moveable plate of
the mill which are travelling at a much quicker speed than those parts
situated near the centre of the said moveable plate, whereby the material
is broken up much quicker than in mills of the ordinary kind, and
damper grain may be ground in mills constructed according to my
Invention than in mills of the ordinary kind.
I prefer to make the flat ridges or furrows on the plates or grinding
surfaces in a radial direction instead of making them curved as usual.
My Invention consists, further, of an improved apparatus for feeding
the grain or other material to be ground, and screening the said grain or
material prior to its passing to the grinding surfaces of the mill. For
these purposes I provide the feeding spout of the mill with a plate or
screen which screens or retains any foreign substance which may be
mixed with the material to be ground; for example, pieces of iron,
stones, straw, or sticks, which said foreign substances tend to choke or
injure the mill. I give a reciprocating motion to the feeding spout by
means of an excentric or cam on the main driving shaft of the mill.
Mills constructed according to my Invention are simple in con-
struction and economical in use, and very durable; and the plates or
grinding surfaces can be easily replaced when necessary by an unskilled
workman.

page_text: VI
filed by the said Samuel Corbett in the Great Seal Patent Office
on the 23rd May 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SAMUEL
CORBETT, of Wellington, in the County of Salop, Agricultural Imple-
ment Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of November, in the
year of our Lord One thousand eight hundred and seventy-five,
in the thirty-ninth year of Her reign, did, for Herself, Her heirs
and successors, give and grant unto me, the said Samuel Corbett,
Her special license, that I, the said Samuel Corbett, my executors,
administrators, and assigns, or such others as I, the said Samuel
Corbett, 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 "IM-
PROVEMENTS IN MILLS FOR CRUSHING, SPLITTING, AND GRINDING VEGETABLE and
MINERAL SUBSTANCES," upon the condition (amongst others) that I, the said
Samuel Corbett, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly 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 Samuel Corbett, 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 thereof, that is to say :-
My Invention consists of the improvements herein-after described
in mills for crushing, splitting, and grinding vegetable and mineral

page_text: My Invention relates, first, to an improved construction of the
grinding or cutting faces or surfaces of the mill, and to the means for
conveying the substances to be crushed, split, or ground to the said
grinding or cutting faces or surfaces.
According to my Invention I form the grinding surfaces of the mill
of two flat discs of chilled cast iron, or white metal, or other hard metal
or alloy, between which surfaces the matter to be ground is fed. Instead
of feeding the substance to be ground through the centre or eye of the
cutting or grinding plates or discs as usual, I feed the said substance
through the back of the fixed cutting or grinding plate and frame of the
mill on one side of the said mill by means of rectangular openings made
in the said cutting or grinding plate and back, the said openings being
situated about midway between the centre and the circumference of the
said plates. By this arrangement the material to be ground is fed to the
grinding surfaces of the mill at those parts of the moveable plate of
the mill which are travelling at a much quicker speed than those parts
situated near the centre of the said moveable plate, whereby the material
is broken up much quicker than in mills of the ordinary kind, and
damper grain may be ground in mills constructed according to my
Invention than in mills of the ordinary kind.
I prefer to make the flat ridges or furrows on the plates or grinding
surfaces in a radial direction instead of making them curved as usual.
My Invention consists, further, of an improved apparatus for feeding
the grain or other material to be ground, and screening the said grain or
material prior to its passing to the grinding surfaces of the mill. For
these purposes I provide the feeding spout of the mill with a plate or
screen which screens or retains any foreign substance which may be
mixed with the material to be ground; for example, pieces of iron,
stones, straw, or sticks, which said foreign substances tend to choke or
injure the mill. I give a reciprocating cross motion to the feeding
spout by means of an eccentric or cam on the main driving shaft of the
mill.
Mills constructed according to my Invention are simple in con-
struction and economical in use and very durable, and the plates or
grinding surfaces can be easily replaced when necessary by an unskilled
workman,

page_text: Having explained the nature of my Invention, I will proceed to
describe with reference to the accompanying Drawings the manner in
which the same is to be performed.
Figure 1 represents in side elevation; Figure 2 in plan, a portion
5 being removed; and Figure 3 in cross section taken on the line a, a, of
Figure 1, a mill for crushing, splitting, or grinding vegetable and mineral
substances containing my improvements.
Figure 4 is an end elevation of the hopper and feeding and screening
spout taken at the feeding slide end of the mill; and Figure 5 is a
section of the arrangement for accurately adjusting the rotating grinding
plate or surface the required distance from the fixed grinding plate or
surface.
Figure 6 represents a vertical section of the mill case and the fixed
and rotating grinding plates or surfaces drawn to a larger scale; and
Figure 7 is a front elevation of the fixed grinding plate; and Figure 8
is a part of the same detached.
Figure 9 represents in cross section, and Figure 10 in plan a portion
of a mill provided with an arrangement for breaking down the grain or
other substance before it reaches the grinding surfaces of the mill.
The same letters of reference indicate the same parts in the several
Figures of the Drawings.
b is the hopper of the mill, and c is the feeding slide of the same.
The position of the said slide cis adjusted so as to regulate the feed by
means of the lever & pivotted to the hopper at d², and connected to the
slide by the pin and slot at . On the hopper is a series of holes at d
a short distance apart, into one of which holes a peg d³ on the lever d
drops and thereby fixes the position of the said hopper slide. Below the
hopper is the feeding and screening spout for feeding the grain or
material to the mill and screening it prior to its passing to the grinding
surfaces of the mill. The said spout is marked e, and the perforated
plate or screen fixed in the said spout is marked f. The combined spout
and screen e, f, has a reciprocating cross or rocking motion given to it,
the said spout working at one end on the bracket g, and at the other
end in the trough on the fixed case of the mill (see Figure 1). The
cross reciprocating or rocking motion is given to the combined feeding

page_text: spout and screen e, f, by the cam i on the driving shaft of the mill,
the said cam i acting alternately on the opposite arms of the fork m, m,
fixed to the bottom of the said spout e (see Figures 1 and 3). As the
grain or material passes from the hopper bit falls on to the screen f
which retains any foreign substance which may be mixed with the
material, such as stones, straws, pieces of iron, and the like, which tend
to choke or injure the mill. The screened wheat or material passes
down the spout to the grinding surfaces n, p, of the mill, n being the
fixed grinding surface, and p the rotating grinding surface. The said
grinding surfaces are made of nearly flat discs of chilled cast iron, or
white metal, or other hard metal or alloy. The rotating grinding
surface p is fixed on the shaft driven by the driving pulley 9 or by
hand. In the fixed grinding plate or surface 12 is a rectangular opening ",
and in the back plates of the casing of the mill is a similar opening s²,
as best seen in Figure 6. The openings 7, 82, are situated about midway
between the centre and the circumference of the grinding plates n, p, as
represented. The grain or material as it leaves the feeding spout e
enters between the fixed and rotating plates or surfaces n, p, at the said
openings s³, 1, so that the material is fed to those parts of the moveable
plate which are travelling at a much quicker speed than those parts
situated near the centre of the said moveable plate, and the material is
thereby broken up much quicker than in mills where the grain is fed
through the eye or centre of the plate.
I make the flat ridges or furrows on the grinding plates n, p, in the
manner best seen in Figure 7, that is to say, I make the said ridges or
furrows in a nearly radial direction instead of making them curved as
usual, the said ridges or furrows converging or becoming narrower as
they approach the edges of the grinding plate or surface.
For the purpose of facilitating the breaking down or reduction of the
grain or material immediately it enters the mill and before it reaches
the grinding part of the mill, I make an opening at t, t (sco Figure 7),
in the fixed grinding plate n and a similar opening in the case s, and I
fix in the said openings a removeable cutting block u (shown separately
in front and side elevation in Figure 8), which block is fixed in its
place by screw pins passed through the cars u², u³, into the casing of
the mill. The ridges or furrows in the cutting block u are coarser and

page_text: stronger than those in the grinding plates n, p, so that the grain or
material as it first enters the mill is acted upon by the rotating plate p
and the strong cutting block u and thereby broken up or reduced. By
this preliminary breaking up or reduction of the grain or material the
subsequent crushing, splitting, or grinding is much facilitated.
The detachable cutting block u may when worn be replaced at a small
cost without taking the mill to pieces, and cutting blocks with ridges
or furrows of different degrees of fineness may be used in the same
mill at the option of the user to suit the material being crushed, split, or
ground. Or instead of using the detachable cutting block u the pre-
liminary breaking up of the grain or material may be effected by the
arrangement represented in Figures 9 and 10. In this arrangement I
use a fluted roller fixed on the rotating shaft of the mill in con-
junction with an adjustable concave fluted surface to, the said parts v, w,
being situated in a small barrel or case a fixed to the plate a² of the
case containing the principal grinding surfaces. The fluted surface to is
jointed to the frame of the mill at w³, and is kept to its work by the
jointed rod w³ acted upon by the coiled spring w³, so that the said
surface w is permitted to yield when any hard substance is introduced
between the two surfaces 10, v. The position of the concave fluted
surface w is adjusted by the turning of the hand wheel w³, and is fixed
by the lock nut 20º. The grain or material from the hopper & passes
between the fixed and rotating fluted surfaces v, w, by the action of
which it receives a preliminary breaking up or reduction, the said grain
or material passing through the opening at z in the end plate a* of the
mill, and through a similar opening in the fixed grinding plate to the
two principal grinding surfaces to be split, crushed, or ground.
b
The position of the moveable or rotating grinding plate or stirface
with respect to the fixed plate or surface n is adjusted and the said
plate permitted to yield when any hard substance is introduced between
the said plates by the arrangement of parts represented in Figures 1, 2,
and 5. A cross piece at the end of the mill carries a central eye 2
formed into a screw box and side eyes 3, 3; these side eyes 3, 3, slide
upon the pins 4, 4, fixed to the frame of the mill, and are pressed home
by the coiled springs 5, 5. In the central eye 2 a vertical slot is made
in which a piece 7 having top and bottom plates works the said piece 7

page_text: carrying a screw 8, the said screw working in the screw box in the
central eye 2.
The back of the piece 7 bears against the end of the
driving shaft 7, see Figure 5. When the hand wheel 10 of the screw 8
is turned the piece 7 is made to slide in one or other direction, and by
bearing on the end of the shaft the position of the moveable plate t
carried by the said shaft may be adjusted. The parts are fixed in their
adjusted position by the lock nut 11 moved by the hand lever 12. When
any hard substance is introduced between the grinding surfaces of the
mill the cross pioce 4, 2, 4, yields, and the moveable plate separates
from the fixed plate, and the grinding surfaces are prevented from being 1
injured.
Having now described the nature of my Invention, and the manner
in which the same is to be performed, I wish it to be understood that I
do not limit myself to the precise details herein described and illustrated,
as the same may be varied without departing from the nature of my
1
Invention; but I claim as my Invention of improvements in mills for
crushing, splitting, and grinding vegetable and mineral substances,―
First. The construction and arrangement of the parts herein-before
described and illustrated in the accompanying Drawings for feeding the
grain or material to be operated upon to the grinding or cutting 2
surfaces of the mill, that is to say, through openings made in the back
of the case of the mill and the fixed cutting or grinding plate or surface,
the said openings being situated about midway between the centre and
circumference of the cutting or grinding plates or surfaces, substantially
as and for the purpose described and illustrated.
2
Secondly. The addition to or combination with the fixed cutting or
grinding plate or surface of the mill of a separable cutting block for
breaking up or reducing the grain or material as it first enters the mill,
as herein-before described and illustrated in Figures 6, 7, and 8 of the
accompanying Drawings; also the arrangement or combination of the 3
parts herein-before described and represented in Figures 9 and 10 for
breaking up or reducing the grain or material before it reaches the
grinding or cutting surfaces of the mill.
Thirdly. The construction and arrangement of the parts and the

page_text: mills, herein-before described and illustrated in the accompanying
Drawings.
In witness whereof, I, the said Samuel Corbett, have hereunto set
my hand and seal, this Sixteenth day of May, in the year of our
Lord One thousand eight hundred and seventy-six.
Witness,
RICHARD SKERRETT,
Clerk to George Shaw,
Birmingham.
SAMUEL CORBETT. (L.S.)