IMPROVEMENTS IN APPARATUS FOR SHARPENING OR DRESSING MILLSTONES
Year: 1880

page_text: LETTERS PATENT to Peter Jensen, of 33, Chancery Lane, London, for an
Invention of "IMPROVEMENTS IN APPARATUS FOR SHARPENING OR DRESSING
MILLSTONES." A communication from abroad by Patrick Graham, of
Stockholm, Sweden, Engineer.
PROVISIONAL SPECIFICATION left by the said Peter Jensen at the Office
of the Commissioners of Patents on the 23rd November 1880.
.
PETER JENSEN, of 33 Chancery Lane, London. "IMPROVEMENTS IN APPARATUS
FOR SHARPENING OR DRESSING MILL STONES." (A communication from abroad
by Patrick Graham, of Stockholm, Sweden, Engineer.)
The Invention herein described refers to the use of one or more toothed, ribbed,
ridged, or pointed discs or rings (of steel, chilled cast iron, or other suitable
material) which rotate with, or on, or between the mill stone or stones to be
sharpened, on or with one or more spindles, spokes, or arms extending from a ring
or boss at the central part or eye of the stone or stones, and so arranged that when
the stones are rotated, or the apparatus is caused to rotate on or between the stone
or stones, and necessary pressure being applied, the teeth, ridges, ribs, or points of
the disc or discs are pressed into the stones, and thus dress or sharpen the grinding
surfaces of same.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Peter Jensen in the Great Seal Patent Office on the 23rd May
1881.
"IMPROVEMENTS IN APPARATUS
A communication from abroad
PETER JENSEN, of 33, Chancery Lane, London.
FOR SHARPENING OR DRESSING MILL STONES."
by Patrick Graham, of Stockholm, Sweden, Engineer.
The Invention herein described refers to the use of one or more toothed, ribbed,
ridged, or pointed discs or rings (of steel, chilled cast iron, or other suitable
material) which rotate with, or on, or between the millstone or stones to be
sharpened, on or with one or more spindles, spokes, or arms extending from a ring
or boss at the central part or eye of the stone or stones, and so arranged that
when the stones are rotated, or the apparatus is caused to rotate on or between the
stone or stones, and necessary pressure being applied, the teeth, ridges, ribs or
points of the disc or discs are pressed into the stones, and thus dress or sharpen the
grinding surfaces of same.
And in order that this Invention may be more fully understood, I will now
proceed to describe the same with reference to the accompanying Drawings.
Figure 1 is a plan, and Figure 2 a side view, about full size, of an apparatus in
its simplest form, and especially suitable for sharpening or dressing mill stones up
to about twenty inches diameter where means usually are provided for regulating
the pressure with which the two millstones are pressed together. Figure 3 is a
vertical section, or it may be taken to represent a horizontal section, through a
pair of millstones having the sharpening apparatus inserted between them ready
for work.
a is the ring or boss placed at the centre or eye of the millstones; three spindles b
are screwed equidistantly into the ring a; and c, c, c, are a number of steel or
chilled iron or other hard rings or cutters, in this case shown with a number of
teeth all round. When the apparatus is placed between the two stones, and one of
the stones is slowly revolved, the apparatus is revolved therewith, and pressure
being applied the teeth on the rings c are pressed into the stones, which are thus
dressed or sharpened on their grinding surfaces. The ring a may be made in 2
halves, as will be presently described with reference to another form of this
apparatus.
Figure 4 is a plan, and Figure a part side view of an apparatus more especially
suitable for stones of more than 20 inches diameter; Figure 6 is a plan, and
Figure 7 a vertical section through a scroll plate which forms one part of this
apparatus. In this form of apparatus the steel rings c are so few in number as to
dress only small portions of the stones if revolved in circles round the centre of
the stone; but in order that the whole face of the stones may nevertheless be
sharpened or dressed the rings c receive a feed or motion in the radial direction,
while they are simultaneously made to traverse round the centre of the stone as in
the first described apparatus. For this purpose the spindles b are held in frames d,
in this case three in number. The frames d can slide in dovetail guides a¹ formed
on a ring a which can turn freely on the ring or flange e¹ of the scroll plate e,
Figures 6 and 7. The frames & have each a tooth or lug d' which work each in a
spiral groove formed in the scroll plate e, which latter is fixed by set screws or
other suitable means to the millstone spindle. As the sharpening rings or cutters c
and c¹ are revolved by contact with one of the revolved millstones, the lugs d
while moving in their spiral grooves of the scroll plate e will carry the frames &
with spindles b and sharpening cutters c, c¹, with them, and bring the latter
gradually nearer to or further from the centre of the millstone (according as the
scrolls are right handed or left handed).

page_text: The rings or cutters c, c¹, are by preference of different form (as shewn), more
especially if the stones are intended for grist grinding. c² is a roller or castor on
each spindle 6 in order to give it better support. The ring a and the scroll plate e
are held together by means of a cover plate f and screws f¹.
Figure 8 is a plan, and Figure 9 side view in section of another form of
apparatus; Fig. 10 is a plan of the scroll plate; Fig. 11 is section of same;
and Figure 12, plan of the scroll plate cover. In this arrangement, which is
specially suitable for the largest millstones, there are shown five spindles b which
are held in bosses a¹ of the ring a capable of sliding radially therein and gearing
with their lugs d' into the spiral grooves in the scroll plate e, which as in the
former case is fixed upon the millstone spindle while the ring a (with spindles or
spokes b having the ring cutters c and c¹ freely revolving thereon) is revolved
between the stationary stone and the revolved stone. The action is the same as in
the last described form of apparatus. By referring more particularly to Figures 8,
10, and 12 it will be observed that the ring a and the scroll plate e are made in
two halves held together by two screws a² and c³ respectively. By this means
the whole apparatus can be inserted and placed in position for work between a
pair of millstones without lifting one entirely off, but by simply raising it a few
inches.
The forms of apparatus described previously may also be constructed in two
halves for the same purpose.
The ring cutters c, c', though here supposed to be of steel or chilled cast iron,
may be of any suitable form, construction, and material, or combination of same
whatever. Figures 13, 14, and 15 show three different forms of ridge cutters.
They may also be set in centres, or arranged to revolve freely in any other suitable
way.
And having thus described and ascertained the nature of this Invention
communicated to me from abroad, I declare that I claim,—
Firstly. The application of revolving ring cutters for the purpose of sharpening
or dressing millstones in the manner substantially as described.
Secondly. An apparatus having ring cutters free to revolve on or with spindles,
or between centres arranged in or on a central ring or frame caused to revolve
under pressure on a millstone or between two millstones, one of which is revolved
against the other, substantially as described.
Thirdly. An apparatus having the general features set forth in claim 2, and in
which the ring cutters while freely revolving describe paths varying in the distance
from the centre of the millstones, substantially as described.
Fourthly. The combinations of parts forming the apparatus herein specially
described with reference to the accompanying Drawings.
In witness whereof, I, the said Peter Jensen, have hereunto set my hand and
seal, this 23rd day of May, in the year of our Lord One thousand eight
P. JENSEN. (L.S.)