IMPROVEMENTS IN MILLS FOR CRUSHING, GRINDING, AND OTHER PURPOSES
Year: 1866

page_text: LETTERS PATENT to William Clark, of 53, Chancery Lane, in the
County of Middlesex, Engineer and Patent Agent, for the Invention of
"IMPROVEMENTS IN MILLS FOR CRUSHING, GRINDING, AND OTHER PURPOSES."—
A communication from abroad by Jean Baptiste Bernard, Charles Laurent,
Emile Peugeot, and Jules Peugeot, Manufacturers, all. of 29, Boulevart
St. Martin. Paris.
Sealed the 6th October 1866, and dated the 13th April 1866.
PROVISIONAL SPECIFICATION left by the said William Clark at the
Office of the Commissioners of Patents, with his Petition, on the 13th
April 1866.
I, WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex,
Engineer and Patent Agent, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN MILLS FOR CRUSHING, GRINDING, AND OTHER PURPOSES," to
be as follows:-
These improvements refer to mills with toothed metallic cones and concaves
or cylinders, as herein-after described. The framing or box in which the
mechanism is located consists of two parts, the lower part A which is secured
on a bench, table, or any suitable bed plate, and the upper part or cap B
formed with a hopper a. The bed plate is represented at Figs. 1, 2, and 3,

page_text: Sheet 1, in longitudinal vertical section, side elevation, and plan. The two
parts A and B are connected longitudinally, and the lower part has bearings
at both ends, between which is fitted the socket of the part A, which is
likewise formed with a bearing in connection with the two before mentioned.
These bearings receive two conical pins which connect together and secure
the parts of the framing; any other suitable connection may however be
adopted, such as a vertical connection, for instance, but I prefer the above
arrangement, which is entirely new and has the advantage over the bolt
connections of facilitating the taking to pieces of the parts when required.
This mode of longitudinal connection has the further advantage of serving
as bearings for the shaft and preventing its playing and getting loose. Up
to this time the cutting surfaces or concaves, either cylindrical or conical,
of portable and other mills have been made of plates, which are rolled and
soldered or brazed without any break in them. I have contrived and claim
as this Invention such improvements in their manufacture as to obtain as an
industrial result a notable saving in hand labour and considerable reduction in
the cost of manufacturing these machines.
The annexed Drawing, Sheet 3, shows the improvements in mill concaves.
Fig. 4 shows in the flat the iron or steel rectangular plate, cut according to
the required sizes for manufacturing the concave; Fig. 5 shows a plan of a
concave formed by rolling out the plate represented at Fig. 4, the two ends
of which are to be simply juxtaposed, but not fixed together, to produce the
continuous form b, shown likewise in Fig. 6, which is an elevation of the
same.
1--
Figs. 7 and 8 show a new arrangement of the teeth, which up to this time
have consisted only of two sorts, the large ones for roughing and the small
ones for finishing. I have introduced an intermediate range, and a greater
number of sets might even. be added. The object of this arrangement is to
progressively prepare the corn or other grain when it is intended to be reduced
to a very fine pulverulent state. Fig. 7 shows the concave opened out, and
Fig. 8 shows the same coiled and forming the cylinder.
I therefore claim as being part of this Invention the construction of mill
concaves in the manner described, whatever may be the form of the said
concaves, either cylindrical, conical, or cylindro-conical, and also with interme
diate sets of teeth.
7
I will mention specially a new arrangement of these concaves which consists
in boring the framing externally to a diameter somewhat more (from one
to three twenty-fifths of an inch) than the external diameter of the concave,
'so that the latter instead of being confined rigidly in the framing may be set

page_text: somewhat loosely for the purpose herein-after mentioned. Whatever care
may be taken in the manufacture of the cutting parts as they are rendered
very hard the tempering imparts slight eccentricity to them. Should, therefore,
the concave be rigidly fitted in its framing when fine grinding is requisite, and
the parts are in close proximity, there would result a friction of the parts
against each other which would affect their duration, while the concave if
somewhat loosely fitted can move and yield to the impulse of the cone; this
arrangement is more particularly claimed. The grooved cones are made
of the forms shown at Figs. 9, 10, and 11, Sheet 3, all of them being concave
at the upper part but of various forms at the lower part. Thus, 1st, the cone
Fig. 9 is convex towards the lower part, which receives the small teeth of the
concave; 2ndly, Fig. 10 is convex likewise down to the lower part, which
receives the small teeth; this lower part has the form of a truncated cone;
instead of being concave as the foregoing one; 3rdly, the cone Fig. 11 is the
same as Fig. 10 as regards its upper and lower parts, but it differs therefrom
in that between the lower part of the frustrum and the convex part there is
an intermediate concave portion. Each of these forms of cone yield satisfactory
results, and may be applied to all sorts of grinding purposes. I would observe
however that when it is intended to produce very fine flour it is preferable as
regards production and readiness of discharge to employ cones of the forms
represented at Figs. 9 and 11, as such concavities are calculated to afford in some
measure in the grinding action, or facility of expansion, whereby obstructions are
prevented. In general should this concavity be intermediate, as at Fig. 11, and
the lower part of the cone terminate in a frustrum the powder or flour obtained will
be of a more regular grain, as the grinding action will take place on a constant
centre, especially if a certain length is given to the fine toothing of the'
frustrum, but as this difference is hardly perceptible it is preferable to make
the concavity in the lower part, as at Fig. 9.
Figs. 12 and 13, Sheet 3, represent a finished cone formed as above
described; its upper part is' formed with helical teeth, the pitch of which
decreases as the diameter of the cone increases: These cutters are intended
to first roughly bruise the corn or other seed, leaving the fine teeth to finish
it afterwards, as above' mentioned, with reference to the concave. I may'
likewise form intermediate teeth, as at Fig. 14, but whatever may be their'
number or the set of the teeth, closer or wider apart, their pitch may vary
between 027 at a minimum and 081 at a maximum of the breadth of the'
periphery of the cone. The large teeth represented at Fig. 12 are about
four inches by two inches in diameter, and a' little more than seven inches in
circumference, which gives a length nearly equal to 048 of the circumference,

page_text: but I may in certain cases vary this rule by extending them from two inches (or
a minimum length of 048) to six inches, the maximum limit of 081; this
rule is applicable to cones of every size. It is obvious that there can be no
rule for the size of the cones, or for the distance apart of the large and small
teeth, as it depends, first, on the number that it is intended to form as regards
the size of the cones, and, secondly, on the nature and size of the grain and
other conditions. As regards the concavities to be formed in the cones with-
out giving any rule as to their relative extent and depth I may remark that
they will always produce a satisfactory effect as regards their ready grinding,
action, and for this reason it may prove of advantage in certain cases to have
several sets on one cone, which new arrangement I claim in the construction
of such cones.
For cones, the lower part of which is of the form of a,
frustrum, I will observe that the inclination of the said frustrum should not
be overlooked, and that the nearer it is to the perpendicular (the perpendicular
could not be used except at the cost of being deprived of the facility of setting
the finishing teeth of the cone and concave closer or wider apart) the better
I have found in practice.
it will prove for the ready delivery of the material.
that this inclination should not be more than nineteen degrees, which relatively
to the horizontal line formed by the bottom or base of the cone will describe an
angle of seventy-one degrees. The inclination of the frustrum may vary between
these outside limits for a cone of the size represented. The frustrum should be
perfectly parallel with that part of the concave against which it acts, for the
more perfect the parallelism the more regularly will the grinding be effected.
As the lower part of the cone is exposed to a more rapid wear from the cutting
surface, being set much finer, it may be made of a separate piece, so as to be
able to replace it when necessary. Fig. 14, already mentioned, and Fig. 15,
which is a horizontal projection of the same seen from beneath suffice to
indicate this arrangement, which is applicable to all the cones whatever may
be their form; at the lower part c, c, are supporting pins; d, d, set screws to
secure the adjustable part to the body of the cone. Not only as already
alluded to should the set apart and pitch of the helical teeth and also the set
apart of the fine toothing be regulated more or less according to the friability
of the substances to be ground, but for the same reason it may be found
desirable to vary the upper diameter of the cone relatively to its lower diameter.
In general, to obtain a good result, it is preferable not to exceed the limits
delineated in the red and blue lines at Fig. 10, which limits will vary of course
in a like proportion for cones of either larger or smaller size than those repre-
sented whenever the proportion of the height and diameter is maintained
but should the proportions between the said parts be changed, in other words

page_text: should cones be made, the length and diameter of which differ in their pro-
portions to those of the specimens represented, it might perhaps be suitable to
modify more or less the limits indicated by the red and blue lines. This
will merely be an alteration determined by practice without there being
any deviation from the improvement claimed as regards the form of the
cones.
I therefore claim, as far as concerns the system of toothed cones before
described, 1st, their general form, and principally their upper convexity;
2ndly, the circular convexities; 3rdly, the frustrum-shaped base within the
limits of inclination as described; 4thly, the helical teeth within the limits for
the pitch of the thread; 5thly, the forming of intermediate teeth; 6thly, the
connection within the same limits between the lower and upper diameters of
the cone; 7thly, the capability of removing the lower portion of the cone so
as to enable it to be replaced by another when worn out.
From the foregoing description of the mechanism it is obvious that the best
means have been adopted to make it work under the best possible conditions,
but whatever care may be taken in its construction it is easy to understand
that such mechanism, consisting of a single toothed cone and concave, will be
subject to considerable strain at the part occupied by the fine teeth relatively
to that of the large teeth. In order to partially relieve this part of the cone
I may employ.cones of a greater length than those shown, so as to be able to
multiply. the intermediate teeth and concavities and impart more progress to
the grinding action, but such cones would be more expensive, and the same
result may be attained by fixing two cones, and consequently two concaves end
to end; each pair having cutting surfaces as before.
Figs. 17 and 18, Sheet 4, show an elevation and section of this latter
arrangement, which will be readily understood without further explanation,
since the coupled parts shown are of the same construction as in the arrange-
ment previously described. Fig. 19, Sheet 4, represents a shaft provided
with a single toothed cone; this shaft is provided with regulating washers
and pallets or agitators. Fig. 20 shows the same mounted in position in a
mill on a smaller scale. It is further requisite to regulate the size of the
mealy particles, especially when cereal matters are acted upon. To this end
the driving shaft is provided at both ends with a key for wedging between it.
and the frame a set of metallic washers f. By removing either one or more:
of the said washers from one side and placing them on the other the shaft is.
slightly moved longitudinally the thickness of a washer, and consequently the
cone is shifted relatively to the concave, which remains stationary. I have
also. contrived. to increase the feed, and consequently the produce of mills.

page_text: with horizontal shafts by means of pallets secured to the driving shaft. These
pallets or agitators 6 are intended to agitate and raise the material, and cause
it to pass more abundantly between the two cutting parts than when left
undisturbed in its recipient. It will be understood that if the action of the
agitator is important for the corn or other seed or grain, it will be much more.
so in the finishing operation, for in this state the substance is more inert and,
stationary than in the form of grain.
This improvement therefore fulfils a most important and useful function.
which I claim as part of the Invention. One or more agitating pallets may
be applied, in which case they may be arranged in the manner of a screw on
the shaft. The base of the cone may likewise be provided with a supple-
mental pallet h, intended to prevent the sinking and obstruction of the ground
substance which might adhere to the periphery of the concave and driving
shaft.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Clark in the Great Seal Patent Office on the
12th October 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CLARK, of 53, Chancery Lane, in the County of Middlesex, Engineer and
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of April, in the year of our Lord
One thousand eight hundred and sixty-six, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said William Clark, Her special licence that I, the said William Clark, my
executors, administrators, and assigns, or such others as I, the said William
Clark, 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 MILLS,
FOR CRUSHING, GRINDING, AND OTHER PURPOSES," a communication to me from
abroad by Jean Baptiste Bernard, Charles Laurent, Emile Peugeot, and Jules,
Peugeot, Manufacturers, all of 29, Boulevart St. Martin, Paris, upon the con-
dition (amongst others) that I, the said William Clark, my executors or adminis-
trators, by an instrument in writing under my, or their, or one of their

page_text: 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 William Clark, do hereby declare the
nature of the 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, reference being had to the Sheets of Drawings hereunto annexed,
and to the letters and figures marked thereon (that is to say) :-
These improvements relate to mills with toothed metallic cones and
concaves or cylinders, as herein-after described. The framing or box in
which the mechanism is located consists of two parts, the lower part A which.
is secured on a bench, table, or any suitable bed plate, and the upper part or
cap B, which is provided with a hopper a. The framing and bed plate are
represented at Figures 1, 2, and 3, Sheet 1, in longitudinal vertical section,.
side elevation, and plan. The two parts A and B are connected longitudinally,
the lower part being provided with bearings at each end, in which is fitted
the socket of the part A, which is likewise formed with a bearing in con-
nection with the two before mentioned. These bearings are connected by
two taper pins C, C, which thus secure the parts of the framing together,
any other suitable connection may, however, be adopted, such as a vertical
connection, for instance, but I prefer the above arrangement which is entirely.
new, and has the advantage over a bolt connection of facilitating the taking.
to pieces of the parts when required. This mode of longitudinal connection.
has also the further advantage of serving as bearings for the shaft, and
prevents its playing and getting loose. Up to this time the cutting surfaces:
or concaves, either cylindrical or conical, of portable or other mills have been
made of plates, which are stamped, rolled, and soldered or brazed without
any break in them, and according to this Invention I make such improve-
ments in their manufacture as to obtain a notable saving in hand labour and.
considerable reduction in the cost of manufacturing these machines.
Sheet 1 of the annexed Drawings shows the improvements in mill
concaves.
Figure 4 shows in the flat the iron or steel rectangular plate cut according
to the 'required sizes for manufacturing the concaves. Figure 5 shows a
plan of a concave formed by coiling the plate. represented at Figure 4, the
two ends of which are to be simply juxtaposed at point 6, but not fixed.
together to produce a continuous form, as shown likewise in Figure 6, which

page_text: is an elevation of the same concave. Figures 7 and 8 show a new arrange-
ment of the teeth or cutting surfaces, which up to this time have consisted
only of two sizes, the larger for roughly grinding, and the smaller for finishing
the grain under treatment; according to these improvements I introduce an
intermediate row or a still greater number of rows might even be used.
The object of this arrangement is to progressively prepare the corn or other
grain when it is intended to be reduced to a very fine pulverulent state.
Figure 7 shows the concave opened out, and Figure 8 shows the same coiled
and forming the cylinder; I therefore claim, as being part of the Invention,
the construction of mill concaves for grinding corn and all kinds of grain, in
the manner described, whatever may be the form of said concaves, either
cylindrical, conical, or cylindro-conical, and also the application of intermediate
sets of teeth.
A further improvement in the arrangement of these concaves consists in.
boring the framing externally to a diameter somewhat. greater (from one
to three twenty-fifths of an inch) than the external diameter of the concave,.
so..that. the latter instead of being confined rigidly. in the framing may
be set somewhat loosely for a purpose I will now mention, for whatever care
may be taken in the manufacture of the cutting parts as they are rendered
very hard, this hard tempering often. 'imparts a slight eccentricity to them.
Should, therefore, the concave be rigidly fitted in its framing when fine
grinding is requisite, and the parts are. in close proximity, there would result
a friction of the parts against each other. which would affect their wear, whilst
the concave if somewhat loosely fitted can move and yield to the impulse of
the cone; this arrangement is more particularly claimed.
The grooved cones are of solid metal of the forms shown at Figures 9, 10,
and 11; Sheet 2, all of them being concave at the upper part, but of various
curved forms at the lower part. Thus, 1st, the cone, Figure 9, is convex
towards the lower. part bearing the small teeth which is slightly concave;
2ndly, Figure 10. is convex. likewise down to the lower part, which is also
similarly provided with small teeth, and is of the form of a truncated cone
instead of being concave as in the foregoing; 3rdly, the cone, Figure 11, is
similar to Figure. 10 as regards the form of its upper and lower parts, but
differs therefrom in having between the lower part of the frustrum and the
convex part an intermediate concave portion. Each of these forms of cones
gives satisfactory results, and may be applied to all sorts of grinding purposes.
I would observe, however, that when it is intended to produce very fine flour
it is preferable as regards production and readiness of discharge to employ.
cones of the forms represented at Figures 9 and 11, as such concavities are

page_text: calculated to afford in some measure to the grinding action a facility of
expansion whereby all choking or obstructions are prevented. In general
should this concavity be intermediate, as at Figure 11, and the lower part of
the cone terminate in a frustrum the powder or flour obtained will be of a
more regular grain, as the grinding action will take place in a constant centre, :
especially if the fine toothing of the frustrum covers any considerable extent;
but as this difference is hardly perceptible, it is preferable to make the con-
cavity in the lower part as at Figure 9 to avoid choking. Figures 12 and 13,
Sheet 2, represent a finished cone of the form above described; its upper part
is provided with helical teeth, the pitch of which decreases as the diameter of
the cone increases. These cutters are intended to first distribute and roughly:
bruise the corn or other grain, leaving the fine teeth to finish it afterwards. As
above mentioned with reference to the concaves I may likewise form intermediate
teeth, as at Figure 14, but whatever may be their number, or the set of the:
teeth closer or wider apart, their length may vary between at a minimum.
and of the breadth of the cone. The large teeth represented at Figure 12
are about four inches in length by two inches in diameter, and a little more than
seven inches in circumference, which gives a length nearly equal to 10% of the
circumference; but the above rule I may vary in certain cases, extending the
limit from two inches or a minimum length to six inches, as a maximum,
or This rule is applicable to cones of all sizes. It is obvious that there
can be no rule for the size of the cones, or for the distance apart of the large
and small teeth, as it depends first on the number that it is intended to form
as regards the size of the cones, and, secondly, on the nature and size of the
grain and other conditions. As regards the concavities to be formed in the
cones, without giving any rule as to their relative extent and depth, I may
remark that they will always produce a satisfactory effect as regards their
ready grinding action, and for this reason it may prove of advantage in certain
cases to have several sets on one cone, and which new arrangement I claim
in the construction of such cones. For cones, the lower part of which is of
the form of a frustrum, I will observe that the inclination of said frustrums
should not be overlooked, and that the nearer to the perpendicular (the.
perpendicular could not be used except at the cost of being deprived of the
facility of setting the finishing teeth of the cone and concave closer or wider
apart) the better it will prove for the ready delivery of the material. I have
found in practice that this inclination should not exceed nineteen degrees, which
relatively to the horizontal line formed by the bottom or base of the cone will de-
scribe an angle of seventy-one degrees. The inclination of the frustrum may vary
between those extreme limits for a cone of the size represented. The frustrum

page_text: should be perfectly parallel with that part of the concave against which it
acts, for the more perfect the parallelism the more regularly will the grinding
be effected. As the lower part of the cone is exposed to more rapid wear,
since the cutters are set much finer, it may be made of a separate piece, so
as to be able to replace it when necessary. Figure 14, already mentioned,
and Figure 15, which is a horizontal projection of the same seen from
beneath, suffice to indicate this arrangement, which is applicable to all the
cones whatever may be their form at the lower part. c, c, are carrying pins;
d, d, set screws to secure the adjustable part to the body of the cone. Not
only, as already alluded to, should the set apart and length of the helical teeth
and also the set apart of the fine toothing be regulated more or less according
to the size and friability of the substances to be ground, but for the same
reason it may be found desirable to vary the upper diameter of the cone
relatively to its lower diameter. In general to obtain a good result it is
preferable not to exceed the limits delineated in red and blue lines at
Figure 16, which limits will vary of course in a like proportion for cones of
either larger or smaller size than those represented whenever the proportion
of the height and diameter is maintained, but should the proportions between
said parts be changed, in other words, should cones be made, the height and
diameter of which differ in their proportions to those of the specimens repre-
sented, it might perhaps be suitable to modify more or less the limits indicated
by the red and blue lines. This will merely be an alteration dictated by
practice without there being any deviation from the improvement claimed as
regards the general form of the cones.
I therefore claim, as far as concerns the system of toothed combs before
described, 1st, their general form, especially the convexity of the upper part;
2ndly, the circular concavities; 3rdly, the frustrum shaped base within the
limits of inclination before given; 4thly, the helical teeth within the limits for
the length of the thread before indicated; 5thly, the forming of intermediate
teeth; 6thly, the connection within the same limits between the upper and
lower diameters of the cone; 7thly, the capability of removing the lower
portion of the cone so as to enable it to be replaced when worn out.
From the foregoing description of the mechanism it is obvious that the
best means have been adopted to make it work under the best possible
conditions; but whatever care may be taken in. its construction it will be
readily understood that such mechanism, consisting of a single toothed cone
and concave, will be subject to considerable strain at the part occupied by the
fine-set relatively to that of the large teeth. In order to partially relieve this
part of the cone I may employ cones of greater length than those shown, so as

page_text: .I
to be able to multiply the intermediate teeth and cavities and impart more
progress to the grinding action; but such cones would be more expensive,
and the same result may be attained by fixing two cones, and consequently
two concaves end to, end, each pair having varied cutting surfaces as before.
Figures 17 and 18, Sheet 2, shows an elevation and section of this latter
arrangement, which will be readily understood without further explanation,
since the coupled parts; shown are of the same construction as in the
arrangement previously described: Figure 19; Sheet12, represents a shaft
provided with a single toothed cone: This shaft is also provided with regu-
lating washers and pallets or agitators.; Figure 20 shows the same mounted
in position in a mill on a smaller scale. It is further requisite to regulate the
size of the particles under treatment, especially when cereal matters are acted
upon. To this end the driving shaft is provided at both ends with a key for
wedging between it and the frame a set of metallic washers f. By removing
either one or more of said washers from one side and placing them on the
other the shaft is slightly moved longitudinally, the thickness of one or more
washers, and consequently the cone is shifted relatively to the concave which
remains stationary. I have also contrived to increase the feed and..con-
sequently the produce of the mills with horizontal shafts by means of pallets
secured to the driving shaft. These pallets or agitators) bare intended to
agitate and raise the material and cause it to pass more abundantly between
the two cutting parts than when left undisturbed in its recipient. It will be
understood that if the action of the agitator is an assistance in the reduction
of the corn or other seed or grain it will be much more so in the finishing
operation when the matters are again passed through the mill, for in this
state the substance is more inert than in the form of grain. This improvement
therefore fulfils a most important and useful function, which I claim as part
of the Invention; one or more stirrers or pallets may be applied, in which
case they may be arranged in the manner of a screw on the shaft. The base
of the cones may likewise be provided with a pallet h, intended to prevent any
accumulation of the ground substance which might adhere to the periphery of
the concave and driving shaft.
Having described the nature of this Invention, and the manner of performing
the same, I declare that what I claim as improvements in mills for crushing
and grinding to be protected by the herein-before in part recited Letters
Patent is,-
First, the peculiar arrangement of the whole of the parts, and particularly
the framing and the method of fixing the same by means of conical pins, as
herein-before described.

page_text: Secondly, the new and, improved construction of the concave, formed with
teeth as described.
Thirdly, the form and construction of the cones, provided with concave
surfaces and spiral or helical teeth, combined and arranged in the manner.
described and as represented in the Drawings.
Fourthly, the arrangement of two pairs of grinding surfaces on the same
shaft, each pair having a peculiar cut, as and for the purpose specified. :
Fifthly, the various modes of feeding the mills by means of agitators, as also:
the modes of regulating the grinding action, all as before described.
In witness whereof, I, the said William Clark, have hereunto set my
hand and seal, this Eleventh day of October, in the year of our Lord
One thousand eight hundred and sixty-six.
17:
Witness,
JAMES DAISH,
53, Chancery Lane,
London.
W. CLARK.
L.B.