IMPROVEMENTS IN MACHINERY FOR GRINDING EMERY AND OTHER MATERIALS
Year: 1858

page_text: LETTERS PATENT to Robert Bruce Goldsworthy, of the City of Man
chester, Emery Manufacturer, for the Invention of "IMPROVEMENTS IN
MACHINERY FOR GRINDING EMERY AND OTHER MATERIALS."
Sealed the 15th October 1858, and dated the 10th May 1858.
PROVISIONAL SPECIFICATION left by the said Robert Bruce Golds-
worthy at the Office of the Commissioners of Patents, with his Petition,
on the 10th May 1858.
I, ROBERT BRUCE GOLDSWORTHY, of the City of Manchester, Emery Manu-
facturer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN MACHINERY FOR GRINDING EMERY AND OTHER MATERIALS," to be as.
follows:-
My Invention consists, first, in weighting the upper part of a pair of mills
with a loose weight or weights; by this means the weight can be regulated
to suit the quality of emery or other material, and the degree of finerness to
which it has to be ground, whereas when the weight is cast with the upper
part of the mill, as now customary, no variation in the weight can be effected.
Secondly, in making the teeth of the mills with a cutting edge, set at right
angles, or nearly so, to the plate of the mill, and a bevelled edge to give
strength to the teeth; also, in an improved mode of placing the teeth on
the plate.
I find in practice that the best arrangement for the teeth on the plate is

page_text: to place them in radial lines from the centre, and in lines parallel to the said
radial lines, but modifications of the mode of placing the teeth may be
suggested by further experiments. The object aimed at is to break or cut
the emery or other material into fine pieces without pulverizing it or reducing
it to dust.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Bruce Goldsworthy in the Great Seal Patent Office
on the 8th November 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
BRUCE GOLDSWORTHY, of the City of Manchester, Emery Manufacturer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of May, in the year of our Lord One
thousand eight hundred and fifty-eight, in the twenty-first year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Robert Bruce Goldsworthy, Her special licence that I, the said Robert
Bruce Goldsworthy, my executors, administrators, and assigns, or such others
as I, the said Robert Bruce Goldsworthy, 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 MACHINERY FOR GRINDING EMERY AND OTHER MATERIALS," upon
the condition (amongst others) that I, the said Robert Bruce Goldsworthy, my
executors or administrators, by an instrument in writing under my, 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 per-
formed, 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 Robert Bruce Goldsworthy, 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 (that is to say):-
The nature of my said Invention consists, first, in the application of a loose
weight or weights to the upper part of a pair of grinding mills, for the

page_text: purpose of being able to regulate the weight thereof according to the sizes of
the emery or other material to be ground.
Secondly, in an improved mode of shaping the teeth of the mills used in
grinding emery and other materials.
And, lastly, in an improved mode of placing or arranging the teeth on the
grinding plates of the mills used in grinding emery and other materials.
And in order that my Invention may be fully understood and readily carried
into effect, I will proceed to describe the means pursued by me, reference being
had to the accompanying Sheet of Drawings and to the figures and letters
marked thereon.
Fig. 1 is an elevation, partly in section, of two pairs of grinding mills, to
which my improvements are applied; Fig. 2 is a plan of the same, shewing
my improved mode of placing or arranging the teeth on the plates of the
mills; and Fig. 3 is a detached view on an enlarged scale, shewing the
improved shape of the teeth of the mills. a is the foundation plate supported
on pillars or otherwise as may be most convenient; to this plate are fixed the
bottom or stationary mills b, b; c, c, are the upper or revolving mills. The
mills may be of the usual construction, or they may be made with teeth
according to our improvements, which will be hereafter described. To the
upper mill or grinding plate c is bolted the loose weight d, which is either cast
in the form of a ring or in segments; this weight with the upper mill are
carried round by the universal balanced rinde e, as shewn in the Drawing, or
by a fixed rinde bolted to the top plate or upper mill; the rinde e is fixed to
the spindle f, which is driven in the usual manner by spur and bevel gearing,
or by a strap and pulleys; the lower end of the spindle f works on the upper
end of the lower spindle g, which may either be stationary, as shewn in the
Drawing, or made to revolve. The grinding mills are surrounded by the
casing h, in which is an opening i for the ground emery or other material to
escape through; the mills are fed by the hopper j in the usual manner.
My improved mode of shaping the teeth of the mills is shewn in Fig. 3;
on referring to this view, it will be seen that the top surface of each tooth is
flat, and the face of the cutting edge marked k is at right angles to the plate b;
the back of the tooth is bevelled off to give strength. These teeth, which are
of the same shape in both the lower and upper mills, are placed in lines
radiating from the aperture in the centre, as shewn in Fig. 2, and then in
lines parallel to the said radial lines; and I place the teeth on the mills in
such wise that when the mills are placed the one above the other for working,
the lines of the teeth shall correspond with each other; (that is to say,) the
teeth on the upper plate would fit in the spaces between the teeth on the

page_text: lower plate. By means of these improvements, the emery when ground is sharp
and keen at the edges, and very little dust is produced in the operation of
grinding, whereas when emery is ground by the machinery hitherto employed,
a considerable quantity is ground to dust, and the edges of the emery are
rounded off, and are thus rendered less effective in use.
The advantages resulting from making the upper grinding mill with a loose
weight are, that the weight of the upper mill can be regulated to the size and
hardness of the emery or other material to be ground, whereas when the
weight is cast with the mill, as now customary, no variation can be made;
there is also a considerable saving in metal, as the same weight can be screwed
or bolted to any number of grinding plates.
Having thus stated the nature of my Invention, and described the
manner of carrying the same into operation, I declare that I claim as of
my Invention,-
First, the application of a loose weight or weights to the upper plate of mills
used in grinding emery and other materials, as described.
Secondly, the improved mode of shaping the teeth of such mills, as shewn
and described in reference to Fig. 3.
And, lastly, the improved mode of placing or arranging the teeth of such
mills, as shewn and described in reference to Fig. 2.
In witness whereof, I, the said Robert Bruce Goldsworthy, have here-
unto set my hand and seal, the Sixth day of November, in the year of
our Lord One thousand eight hundred and fifty-eight.
Witness,
H. B. BARLOW,
Manchester.
ROBERT BRUCE GOLDSWORTHY. (L.S.)