IMPROVEMENTS IN GRINDING AND PULVERIZING GUMS, GUM RESINS, AND OTHER DRUGS, AND ARTICLES OF SIMILAR CHARACTER
Year: 1853

page_text: LETTERS PATENT to Richard Archibald Brooman, of the firm of
Robertson, Brooman, and Co., of 166, Fleet Street, in the City
of London, Patent Agents, for the Invention of "IMPROVEMENTS IN
GRINDING AND PULVERIZING GUMS, GUM RESINS, AND OTHER DRUGS, AND
ARTICLES OF SIMILAR CHARACTER."-A communication.
Sealed the 20th September 1853, and dated the 12th April 1853.
PROVISIONAL SPECIFICATION left by the said Richard Archibald
Brooman at the Office of the Commissioners of Patents, with
his Petition, on the 12th April 1853.
I, RICHARD ARCHIBALD BROOMAN, of the firm of Robertson, Brooman,
and Company, of 166, Fleet Street, in the City of London, Patent
Agents, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN GRINDING AND PULVERIZING GUMS, GUM RESINS, AND OTHER
DRUGS, AND ARTICLES OF SIMILAR CHARACTER," to be as follows:-
This Invention consists in an improvement in the mills commonly
used for grinding gums, gum resins, and other drugs, or articles of
similar character, whereby such substances may not only be dis-
integrated with great rapidity, but the required impalpable powder is

page_text: produced at one operation, thus obviating the necessity of submitting
the matter to the usual additional process known as dusting. The
construction is as follows:-A circular bed stone is made of granite or
other suitable material, rising in the centre, in the form of a cone, as
shown at (a). This conical form is employed for the purpose of en-
abling the advancing edge of the muller (which has a plane surface) to
pass over or mount upon the material submitted, instead of pushing
that away, as would be the case where both surfaces plane. The
bed stone, thus formed is firmly fixed upon a suitable frame, and sur-
rounded with a curb of wood (b), as usual in the class of mills known
as chasers. A shaft (c) passes through a suitable opening in the bed
stone, and is made to revolve by appropriate connexion with any first
motor. Upon the bed stone are placed one or more "mullers" (d),
which are of granite or other suitable material. The face in contact
with the bed stone is a circular plane, of a diameter rather less than a
radius of the bed stone, and the muller is diminished in size towards
the upper end, in order that it may not come in contact with the curb,
in the manner shown in Fig. 1. In the centre of the upper end of the
muller a hole (e) is drilled, extending downward nearly to the face, and
at right angles with that. In this hole a spindle is firmly fixed, and
upon this the muller revolves in the ends of an arm (f), extending from
the shaft c. The arm is placed a short-distance above the muller, in
order that when the feed may happen to be too abundant the muller
may be permitted to rise over it. Upon one of the arms (f) is placed a
lever, standing in a vertical position, or nearly so, as seen at (g). It has
play upon a pin (g); and upon the head of the spindle is an adjustable
screw, the head of which works into a cranked arm of the lever (y), as
shown. The lever strikes against a pin projecting from a vibrating
rod k, imparting to that a motion similar to that of the usual damsel or
beater employed for regulating the feed in mills of this class. The
curb may be of any height suitable to the substance to be reduced,
and the whole is enclosed in a tight casing. The operation will be
thus Rotary motion being given to the shaft, the mullers are driven
round by the spindles, and bear upon the bed stones only on the line of
a radius, the bed receding from the face of the muller on both sides in

page_text: a curve, as seen in figure Fig. II., (which is a section on the line (x, x,) of
Fig. I.; and as, by reason of the conical form of the bed, the flat surface
of the muller is more nearly in contact with the bed on the outer position,
as at (m), than on the inner, at (n), the onward motion of the muller causes
it to revolve upon the spindle. A simple forward movement would
bave the effect only of rubbing the substances introduced between the
stones; but, as a point on the periphery of the face of the muller will
describe a hypocycloid upon the material on the bed stone, that will
then be also ground or cut. Although in the mills in common use the
particles of many substances are obtained light enough to rise over the
curb, as rhubarb, &c., they are yet susceptible of further disintegration
by the simple operation of the duster. In this machine the muller is
constantly assuming a new line of bearing on the conical surface of the
bed stone, and the substances between are reduced by a rotating grind-
ing motion on the line of contact. If the material be supplied too
rapidly and accumulated beneath the muller, that will rise, the spindle
moving upward through the arm (f), causing the upper end of the
lever (g), to be thrown toward the centre, and in this position it will
pass the pin on the vibrating rod without touching it; and thus the
feed would cease for a time.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Richard Archibald Brooman, in the Great Seal
Patent Office, on the 12th October 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
RICHARD ARCHIBALD BROOMAN, of the firm of Robertson, Brooman,
and Company, of 166, Fleet Street, in the City of London, Patent
Agents, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twelfth day of April, in the year of
our Lord One thousand eight hundred and fifty-three, in the sixteenth
year of Her reign, did, for Herself, Her heirs and successors, give and.
grant unto me, the said Richard Archibald Brooman, Her special
licence that 1, the said Richard Archibald Brooman, my executors,

page_text: administrators, and assigns, or such others as I, the said Richard
Archibald Brooman, 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 AND PULVERIZING GUMS,
GUM RESINS, AND OTHER DRUGS AND ARTICLES OF SIMILAR CHARACTER,"
(communicated to me by a foreigner residing abroad,) upon the con-
dition (amongst others) that I, the said Richard Archibald Brooman,
by an instrument in writing under my hand and seal, should particu-
larly 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 Richard Archibald Brooman,
do hereby declare the nature of the said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement thereof, reference being had
to the drawings hereunto annexed, that is to say:
This Invention consists of improvements in the mills commonly used
for grinding gums, gum resins, and other drugs, or articles of similar
character, whereby such substances may not only be disintegrated with
great rapidity, but the required impalpable powder be produced at one
operation; thus obviating the necessity of submitting the matter to the
usual additional process known as "dusting."
The construction of the improved mill is represented in Figures 1,
and 2, of the drawings annexed, and is as follows:-A circular bed
stone is made of granite or other suitable material, rising in the centre
in the form of a cone, as shewn at a. This conical form is employed
for the purpose of enabling the advancing edge of the muller, which
has a plane surface, to pass over or mount upon the material submitted,
instead of pushing that away, as would be the case were both surfaces
plane. The bed stone thus formed is firmly fixed upon a suitable
frame, and surrounded with a curb of wood b, as usual in the class of

page_text: mills known as "chasers."
A shaft, passes through a suitable open-
ing in the bed stone, and is made to revolve by appropriate connection
with any first motor. Upon the bed stone are placed one or more
"mullers" d, which are composed of granite or other suitable material.
The face in contact with the bed stone is a circular plane, of a diameter
rather less than a radius of the bed stone, and the muller is diminished
in size towards the upper end, in order that it may not come in contact
with the curb, in the manner shewn in Figure 1. In the centre of the
upper end of the muller a hole e, is drilled, extending downward nearly
to the face, and at right angles with it. In this hole a spindle is firmly
fixed, and upon this the muller revolves in the ends of an arm f, ex-
tending from the shaft c. The arm is placed a short distance above the
muller, in order that when the feed happens to be too abundant the
muller may be permitted to rise over it. Upon one of the arms f, is
placed a lever, standing in a vertical position, or nearly so, as seen
at g. It has play upon a pin g'; and upon the head of the spindle is
an adjustable screw, the head of which works into a cranked arm of the
lever g, as shown. The lever strikes against a pin projecting from a
vibrating rod k, imparting to that rod a motion similar to that of the
usual damsel or beater employed for regulating the feed in mills of this
class. The curb may be of any height suitable to the substance to be
reduced, and the whole is enclosed in a tight casing.
The operation of the mill is as follows:-Rotary motion being given to
the shaft, the mullers are driven round by the spindles and bear upon the
bed stone only on the line of a radius, the bed receding from the face of
the muller on both sides in a curve, as seen in Figure 2, which is a sec-
tion on the line x, x, of Figure 1; and as, by reason of the conical form
of the bed, the flat surface of the muller is more nearly in contact with
the bed on the outer portion, as at m, than on the inner, at n, the
onward motion of the muller causes it to revolve upon the spindle. A
simple forward movement would have the effect only of rubbing the
substances introduced between the stones; but, as a point on the peri-
phery of the face of the muller will describe a hypocycloid upon the
material on the bed stone, the material will then be also ground or
cut. Although in the mills in common use the particles of many sub-

page_text: stances, as rhubarb, &c., are obtained light enough to rise over the
curb, they are yet susceptible of further disintegration by the simple
operation of the "duster." In this machine the muller is constantly
assuming a new line of bearing on the conical surface of the bed stone,
and the substances between are reduced by a rotating grinding motion
on the line of contact.
If the material be supplied too rapidly and accumulated beneath the
muller, that will rise, the spindle moving upward through the arm f,
causing the upper end of the lever g, to be thrown toward the centre;
and in this position it will pass the pin on the vibrating rod, without
touching it, and thus the feed would cease for a time.
And having now described the nature of the said Invention, and in
what manner the same is to be performed, I declare that what I
claim is, the construction of a mill in which the grinding surfaces
shall consist of a plane or planes operating upon a cone, as set forth;
also, the lever g, in combination with the muller, for the purpose
of regulating the feed; the whole being constructed and operating
substantially as set forth.
In witness whereof, I, the said Richard Archibald Brooman, have
hereunto set my hand and seal, this Seventh day of October,
One thousand eight hundred and fifty-three.
R. A. BROOMAN.
(L.S.)