IMPROVEMENTS IN COFFEE MILLS
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by Charles Frederick Clark and
George Bruerton at the Office of the Commissioners of Patents,
with their Petition, on the 6th June 1872.
We, CHARLES FREDERICK CLARK, Ironfounder, and GEORGE BRUER-
TON, Engineer, both of Wolverhampton, in the County of Stafford, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
COFFEE MILLS," to be as follows :-
Our Invention has for its object the more easy and accurate regulation
of the distance between the grinding surfaces in that kind of mill,
crdinarily known as a coffee mill, in which grinding is effected by means
of a serrated cone working within a hollow cone similarly serrated. The
adjustment between the surfaces of the cones in mills so constructed
(and which may be applied to grinding other substances as well as
coffee) is ordinarily effected by means of a screw, against the end of
which the spindle carrying the inner cone is supported in such a manner
that by tightening the screw the surfaces of the cones are made to
approach, and the substance which is being ground is reduced to a fine
powder, whilst by loosening the screw the surfaces of the cones are
withdrawn from each other and a coarse powder is produced. By
this arrangement, as ordinarily constructed, considerable difficulty is
experienced in adjusting the screw described, and our Invention consists
of improved methods of adjusting the spindle of the inner cone described,

page_text: so as to regulate the distance between the surfaces of the cones as
desired. For this purpose we arrange a lever under the inner cone,
one end of which lever turns upon a centre attached to a suitable point
in the frame of the mill, and the other end is jointed to a bar which
passes up through a hole in the top of the mill, and has its upper
extremity screwed and fitted with a thumbscrew. This lever is so
arranged that the spindle of the inner cone rests upon it at a point
between the hinge described and the screwed bar, and in this manner
by tightening the thumbscrew the inner cone is raised and the grinding
is finer, whilst if the thumbscrew is loosened the inner cone is lowered
and the grinding is coarser.
Sometimes instead of a lever as just described we use a screw turning
in a cross bar which is fixed across the bottom of the outer cone. But
instead of turning this screw in the usual way (which is found very
inconvenient) by means of a screwdriver, we fit or attach a lever to the
head of the screw and we bring up the other end of this lever through a
suitable curved opening in the body of the mill. By this arrangement
the screw can be turned, and thus the inner cone raised or lowered by
moving the outer end of the lever, which can be fixed in any desired
position by means of a thumbscrew.
Sometimes we use the same arrangement of lever and thumbscrew,
but instead of a screw supporting the inner cone we use a moveable pin
or bearing having inclined planes working against corresponding inclined
planes formed upon a cross bar which supports it. In this manner the
pin or bearing is raised or lowered by moving the end of the lever which
is fitted or attached to it.
Sometimes for the purpose of tightening or loosening the screw which
supports the pin of the inner cone we make bars or wings to the head
of the screw, and we make an opening in the bottom of the mill
sufficiently large to admit the hand or fingers for the purpose of
adjusting the screw. By this method the screw can be adjusted by
hand without any screwdriver or other tool, after removing the drawer
which is usually fitted into the lower part of such mills to receive the
ground substance.
The accompanying Drawings are in illustration of our Invention.
Figure 1 is a section of an ordinary hand coffee mill with the handle
removed, shewing our apparatus attached. A is the body of the mill;

page_text: B is the outer serrated grinding cone; and C is the inner serrated cone
fixed upon the spindle D which works in the bearing E at its upper
end, and in the cross bar F at its lower end; G is the lever turning
upon a hinge H and supporting the spindle D at the point L. The other
end of the lever G is connected to the bar K, the upper end of which is
screwed, and after passing through a hole in the top of the mill is fitted
with a thumbscrew L. When the lever G is raised by means of the
thumbscrew L the inner cone C is raised and the grinding is fine, and
when the lever G is lowered the cone C is lowered and the grinding is
coarse.
In Figure 2 the pin D of the inner cone C is supported by a screw G
working through the cross bar F. To the head of the screw a lever K
is fitted, the end of which is shewn bent up and working against a
slot M (shewn in Figure 4) formed in the upper part of the mill which
is made circular in plan. A thumbscrew N works in the slot and is
fitted into the end of the lever, which can thus be fixed in any desired
position. We make the head of the screw G polygonal in plan, as
shewn in Figure 3, so that the lever K can be fitted upon it in any
required position.
In Figures 5, 6, and 7, the pin D of the inner cone C is shewn
supported by the bearing G which works in the cross bar F, upon which
inclined planes are formed, as shewn in plan at Figure 6. To the upper
part of the bearing G a lever K (shewn in plan from below at Figure 7)
is attached, having inclined planes corresponding to those upon the
bar F. The lever K can be regulated and fixed with a thumbscrew in
the same way as that shewn in Figures 2, 3, and 4,
In Figure 8 the pin D of the inner cone C is shewn supported by a
screw G in the same way as in Figure 2, but the screw is arranged as
a thumbscrew, so that it can be regulated by the fingers or hand
introduced through the large opening W in the bottom of the mill,
the drawer S being removed when necessary to allow access to the
screw.