IMPROVEMENTS IN MILLS FOR GRINDING COFFEE AND OTHER SUBSTANCES.
Year: 1874

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
--
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN MILLS FOR GRINDING COFFEE AND OTHER SUBSTANCES.".
A communication from abroad by Eugène Anduze, of Orleans,
France.
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 20th March 1874.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN MILLS FOR GRINDING COFFEE AND
OTHER SUBSTANCES," to be as follows:-
This Invention relates to improvements in mills for grinding coffee,
pepper, and other substances, the chief advantages of which are, that, —
-
1st. The foreign matters often found mixed with coffee and pepper,.
such as small stones and wood, are ground without difficulty..
01
mi.
11

page_text: 3rdly. It can suffer no injury from nails, which are often contained in
coffee imported in barrels, as in the event of one getting into the mill its
working would be stopped until the obstruction is removed, which may
bo readily effected by simply separating the discs to allow the nail to
fall out.
4thly. The mill will work equally well in the one or the other direction.
5thly. A larger product is obtainable than with any other kind of mill
of a uniform quality, the coffee being as finely granulated as desired
without being reduced to powder.
:
C
6thly. The mill will remain efficient for a very considerable time 1
without needing repairs, the toothed dises meshing closer with cach
other as they wear in working, so that the regularity of the grinding is
not impaired.
The mill consists of two grinding discs or cones, one fixed and the
other rotary. Each is furnished on its grinding face with projecting
teeth disposed in concentric circles, and with alternate spaces in some
cases, the teeth being generally quadrangular and segmental in form at
the base, and converging towards the centre, the width, length, and
height of the different circles of teeth diminishing from the centre
towards the circumference. These grinding surfaces mesh together, and
in one arrangement intended for use in grocery and other establishments
the discs are disposed vertically, the movable disc being keyed on a
horizontal axis worked by a winch handle, and the discs being enclosed
in a suitable box or casing provided with a hopper, from which the
berries are fed to the grinding discs. In this arrangement the teeth are
quadrilateral and angular or pyramidal in form. The berries pass from
the hopper through an opening in the fixed disc, and are first broken by
the coarser teeth near the centre, and then reduced by the finer teeth
nearer the circumference, the fineness to which it is ground being
regulated by adjusting the movable disc closer or not to the fixed one.
:
In another arrangement the grinding surfaces are worked horizontally,
being mounted on a vertical axis, and are of conical form to facilitate
the delivery of the ground material. The fixed cone is hollow, and lias
teeth on its internal surface, the movable cone having teeth on its
external surface, and working in the fixed cone.
The coffee berries are introduced at openings in the fixed conc, which
is fixed to the bottom of the hopper.. In this arrangement the teeth

page_text: near the centre of the fixed cone are of squared form with parallel ends,
against which the coffee berries become lodged. The revolving cone is
also armed with teeth, which are bevelled to a projecting central acute
angle at the one end, and terminate in two lateral angles at the opposite
end. The exterior circles of teeth in both cones have inclined sides
meeting at an apex or ridge, as in the other arrangement.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 19th September 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date tlic Twenticth day of March, in the year
of our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alexander Melville Clark, Her special
licence that I, the said Alexander Melville Clark, my executors, adminis-
trators, and assigns, or such others as I, the said Alexander Melville
Clark, my executors, administrators, and assigns, should at any timo
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 MILLS FOR GRINDING COFFEE AND OTHER SUBSTANCES," a
communication to me from abroad by Eugène Anduze, of Orleans,
France, upon the condition (amongst others) that I, the said Alexander
Melville Clark, my exccutors or administrators, by an instrument in
writing under my, or their, or one of their hands and scals, 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..

page_text: NOW KNOW YE, that I, the said Alexander Melville Clark, 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 two accompanying
Sheets of Drawings, and to the letters and figures marked thereon
(that is to say)—
This Invention relates to improvements in mills for grinding coffee,
pepper, and other substances. The principal advantages of these improved
mills are,
-
1st. The foreign matters often found mixed with coffee and pepper, 1
such as small stones and pieces of wood, are ground without any
difficulty.
2ndly. The mills may be readily taken to pieces and put together
again.
3rdly. It is not liable to be injured by the nails frequently found in 1
coffee imported in barrels, for should one get into the mill its working
would at once be stopped before any damage could be done. The
obstruction can readily be removed by simply separating the discs a
short distance to allow it to fall out.
4thly. The mill will work equally well in cither direction.
5thly. A larger product is obtainable than with any other kind of mill
of a uniform grade, the coffee being as finely granulated as may be
desired without being reduced to an impalpable powder.
2
6thly. The mill will remain efficient for a very considerable time with-
out needing repairs, the grinding dises meshing closer with each other as 2
they wear in working, so that the regularity of the grinding is not
impaired.
The mill consists of two grinding discs or cones, one fixed and the
other rotary. Each is furnished on its grinding face with projecting.
teeth, which mesh with those on the other, cach being disposed in con- 3
centric circles, those nearest the centre being alternated with spaces.
The teeth are generally quadrangular in form at the base, with the ends
inclining towards the centre of the disc; the dimensions of the teeth
diminishing from the centre towards the circumference.
In order that the Invention may be more readily understood I have 35

page_text: ustrated it in the accompanying Drawings, in which the precise form
of the teeth will be readily seen.
Figure 1 shows a vertical section of a mill intended for use in grocery
and other establishments, the discs being represented in elevation..
Figure 2 shows face views of the two grinding discs.
Figure 3 shows the discs in section in their working position.
A is a flat circular casing enclosing a pair of cast-iron discs B, C, of
which the former is fixed and forms one side of the casing, whilst the
other is keyed on a horizontal spindle D turning in bearings in the disc B
at one end, and in the casing A at the other. The stationary disc B has
an aperture E above the centre, provided with a spout surmounted by a
hopper H, in which the coffee berries and other substances are placed to
be fed to the grinding discs through the said spout and aperture. The
one disc is made flat, the other being slightly dished, as shown,.or both
may be similarly dished in order to accommodate teeth of a greater
height in the inner circles near the centre of the discs than those in the
outer circles. a, a, a, represent the different rings of teetli, which are
more or less alike in form. It will be seen that the teeth in the inner
circles are considerably larger and coarser than those in the outer circles.
The former are A shaped in cross section, their inclinéd sides meeting
in a central ridge, and they have triangular shaped ends inclining
inwards, as shown clearly by the shaded teeth of disc B, Figure 2. The
finer teeth in the outermost circles are pyramidal in form, their inclined
sides and ends meeting in a apex, as shown. Thus between each two
rings of teeth there is a sort of V shaped groove corresponding to the
form of the tecth of the other disc which move in it, the two thus
meshing together, as shown in Figure 3. The height of the teeth, and
consequently the depth of the groove in which they run, gradually
diminish from the centre outwards, the teeth in the innermost circle
being about twice the height, more or less, of those in the outermost
circle, so that the substances passing through the mill will be gradually.
granulated or reduced to small fragments.
It will be seen that the teeth in all the circles, except that at the
circumference, are alternated with vacant spaces of a variable length:
disposed as shown. F, hand wheel, by which the mill is operated, but in.
the case of large mills this might be replaced by a band pulley driven
from a steam engine or other motor. The pulverized or granulated

page_text: substances escape at the edges of the discs, and are collected by the
casing A, and fall into a receptacle G at bottom provided for the purpose.
To regulate the degree of fineness of the product washers are interposed
between the nut or collar on spindle D and the adjacent bearing in order
to bring the discs into closer proximity as desired.
In order to augment the product the innermost circle of coarse teeth
on both discs might be omitted to more readily admit the berries or other
substances to be ground.
Figure 4 is a central vertical section of a coffee mill for domestic use:
In this case the grinding discs or concs are on a vertical axis.
Figure 5 shows face views of the two cones; and Figure 6 shows
similar views of two cones with teeth of different shape.
The same letters of reference are used to indicate similar parts to those
before described, so that a particular description of cach will be un-
necessary.
B is a hollow or female conc, furnished with teeth and fixed in tho
bottom of a conical hopper H by screws or otherwise. C is the malo
cone corresponding to the interior of conc B, and also furnished with
similar teeth, which mesh together, as seen in the section. The conc C
is keyed on the spindle D, which passes up through a bearing in the a
cover I, and is provided with a handle F, and adjusting washer or screw
or other means of regulating the distance between the cones. A is tho
casing in which the working parts are enclosed. A hinged lid, not
shown, is provided in the lid I for introducing the substances to be.
ground. The fixed cone B has apertures B¹, Figure 5, around the 2
central bearing of the spindle D to admit the substances between the
cones.
It will be seen. that the teeth do not stand out perpendicular to the
surface of the cone on which they are formed, but the centre line of cach
is in a vertical direction, that is to say, perpendicular to the base of the
cone, but they may be otherwise arranged. The teeth differ somewhat
in form from those of the mill first described, but their shape will be
readily understood from the Drawing. They are alternated with spaces,
except in the outermost circle on the cone C and the two outermost
circles on conc B, and each circle forms with the next a V groove in
which the teeth of the outer.conc work.

page_text: In Figure 6 the larger teeth of the fixed cone have flat vertical ends,
against which the berries lodge, and are crushed by the teeth of the
movable conc, which are bevelled to a central salient angle at the one
end and a receding angle at the opposite end.
In Figures 1 and 2 the mill shown is drawn to about half size, and in
Figures 3 and 4 full size, but the dimensions may be varied in both cases
according to requirements...
Having described the nature of the Invention, and the manner of
performing the same, I declare that what I claim as the Invention to be
protected by the herein-before in part recited Letters Patent is,-
1st. In a mill for grinding coffee and other substances a pair of
grinding discs when provided with teeth of the form shown disposed in
concentric circles or series graduated from the centre outwards, the two
discs meshing together and operating, all substantially as herein set
forth.
2ndly. A mill consisting of a pair of cones constructed and arranged
as described when furnished with graduated teeth of the form and
arrangement substantially as herein shown and described, the two concs
meshing together and operating as herein explained.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Eighteenth day of September,
in the year of our Lord One thousand eight hundred and seventy-
four.
Witness,
HARRY SWALES,
53, Chancery Lane,
London.
A. M. CLARK. (L.S.)