CERTAIN IMPROVEMENTS IN THE METHOD OR PROCESS OF GRINDING METALLIC ARTICLES, AND IN THE MECHANISM CON- NECTED THEREWITH
Year: 1869

page_text: LETTERS PATENT to William Mitchell, of Manchester, in the County of
Lancaster, for the Invention of "CERTAIN IMPROVEMENTS IN THE METHOD
OR PROCESS OF GRINDING METALLIC ARTICLES, AND IN THE MECHANISM CON-
NECTED THEREWITH."
Soaled the 23rd November 1869, and dated the 24th May 1869.
PROVISIONAL SPECIFICATION left by the said William Mitchell at
the Office of the Commissioners of Patents, with his Petition, on
the 24th May 1869.
I, WILLIAM MITCHELL, of Manchester, in the County of Lancaster,
do hereby declare the nature of the said Invention for "CERTAIN IM.
PROVEMENTS IN THE METHOD OR PROCESS OF GRINDING METALLIC ARTICLES, AND IN
THE MECHANISM CONNECTED THEREWITH," to be as follows:-
My Invention relates more especially to the grinding of metal
castings, but also may be employed for the purpose of grinding
sharpening edge tools, files, or similar articles, and the improvement
consists in applying to the periphery of a revolving disc made of metal,
wood, or other suitable material a continuous stream of sand and water

page_text: which is contained in a vessell or receptacle from which it is caused
to flow through an opening or valve during the time the disc is revolving,
the said valve being closed, and the flow of sand and water is cut off
during the time the disc is not in motion. This may be effected by
connecting the levers actuating the valve to the ordinary stop motion
of the grinding disc.
Another arrangement of applying the sand and water to the periphery
of the disc may he accomplished by placing the mixture in a trough
underneath the disc, in such a position that the disc will be allowed
slightly to dip therein, whereby it will be constantly transferred to the
periphery of the same whilst revolving, the said sand and water during
the time the dise is revolving being kept in a state of agetation. The
sand and water may also if required be fed separately on to the periphery
of the disc so as to comingle or mix together prepantory to their being
brought into contact with the metallic articles submitted to the periphery
of the disc for grinding. In lieu of sand pulverized flint, quartz, or
other similar materials may also be employed with advantage, the use
of sand or pulverized materials being discontinued so soon as the outer
roughness of the casting is reduced, the finishing or completing of the
grinding being effected upon the damp surface of the periphery of the
disc
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Mitchell in the Great Seal Patent Office
on the 24th November 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
MITCHELL, of Manchester, in the County of Lancaster, send greeting.
WHEREAS Fler most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of May, in the year of our
Lord One thousand eight hundred and sixty-nine, No. 1593; in the
thirty-second year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said William Mitchell, Her special
license that 1, the said William Mitchell, my executors, administrators,
and assigns, or such others as I, the said William Mitchell, my
executors, administrators, and assigns, should at any time agreo
with, and no others, from time to time and at all times thereafter

page_text: "
during the term therein expressed, should and lawfully might make,
usc, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"CERTAIN IMPROVEMENTS IN THE METHOD OR PROCESS OF GRINDING METALLIC
ARTICLES, AND IN THE MECHANISM CONNECTED THEREWITH,' upon the con-
dition (amongst others) that I, the said William Mitchell, my execu-
tors or administrators, by an instrument in writing under my hand
and scal, or their, or one of their 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 Mitchell, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement and accompanying Drawings, that is to
say
My Invention relates more especially to the grinding of metallic
castings but also may be employed for the purpose of grinding or sharpeu-
ing edge tools, files, or similar articles, and the improvement consists in
applying to the periphery of a revolving disc made of metal, wood, or
other suitable material a continuous stream of sand and water, which
is contained in a vessel or receptacle from which it is caused to flow.
through an opening or valve during the time the disc is revolving, the
said valve being closed and the flow of sand and water cut off during
the time the disc is not in motion. This may be effected by connecting
the levers actuating the valve to the ordinary stop motion of the
grinding discs.
Another arrangement of applying the sand and water to the periphery
of the disc may be accomplished by placing the mixture in a trough
underneath the disc in such a position that the disc will be allowed
slightly to dip therein, whereby it will be constantly transferred to
the periphery of the same whilst revolving, the said sand and water
during the time the disc is revolving being kept in a state of agitation.
The sand and water may also if required be fed separately on to the
periphery of the disc so as to commingle or mix together preparatory to
their being brought into contact with the metallic articles submitted
to the periphery of the disc for grinding. In lieu of sand pulverized

page_text: flint, quartz, or other similar minerals may also be employed with ad-
vantage, the use of sand or pulverized minerals being discontinued so
soon as the outer roughness of the casting is reduced, the finishing or
completing of the grinding being effected upon the damp surface of the
periphery of the disc..
In order that the Invention may be better understood in detail, I
have hereunto attached a Sheet of Drawings illustrating, as an example,
one arrangement and construction of grinding disc and apparatus in
connection therewith, that will uniformly distribute, according to the
velocity of the disc, whilst revolving a stream of sand and water to the
surface thereof to be employed for grinding metallic articles. Similar
letters of reference being marked upon corresponding parts on all the
Figs. alike.
Fig. 1 represents a side elevation of the grinding disc, shewing
the trough containing the sand and water in section, and Fig. 2,
represents an end elevation of the same. In these Figs a, a, represents
the disc, which may be composed of metal, wood, or other material
but what I more particularly prefer is a disc, the periphery of which
or other surface thereof is covered over with a thick coating of a com-
position containing emery or other grinding substance b; this disc is
mounted in bearings supported on the framing c. The sand and water
mixture d is contained in the trough e into which the lower periphery
of the disc a is immersed; the agitation of the liquid when the disc is
in motion is increased or diminished according to the velocity at which
the disc revolves through the medium of the agitator f, actuated by a
crank, stud, or other equivalent on the spindle of the disc, thus when
rough grinding is required the accelerated speed of the disc causes in-
creased agitation, and a consequent increased supply of sand to the peri-
phery of the grinding disc, but when finishing off after grinding the speed
is reduced so as to be adapted to the requirement of the articles under
the operation of grinding. Although I have only shewn and described
one arrangement of supplying sand and water to the periphery of a
grinding disc or wheel it will readily be understood that the supply of
sand and water to the periphery or other surfaces of a grinding disc
to be employed as a grinding medium may be effected in various ways,
the arrangement herein shewn and described being the best I have
hitherto found, and which has been employed for grinding cutters and
other portions of agricultural implements

page_text: Having now described the nature of my said Invention, together
with the method of carrying the same into practical effect, I wish it to
be distinctly understood in conclusion that I claim, the novel employ-.
ment, use, and adaption of sand and water to the periphery of a
revolving disc or wheel to be employed therewith, as a medium for
grinding metallic articles in contradistinction to stone as now employed
for the same purposes, as herein-before described, set forth, and fully
illustrated in the Drawing attached.
In witness whereof, I, the said William Mitchell, have hereunto,
set my hand and seal, this the Twenty-third day of November, in
the year of our Lord One thousand eight hundred and sixty-
nino.
Witnessed by
THOMAS WRIGLEY,
Agent to the Petitioner,
20, Cross Street,
Manchester.
WILLIAM MITCHELL. (L.S.)