IMPROVEMENTS IN DRESSING MILLSTONES AND IN THE MACHINERY OR APPARATUS EMPLOYED THEREFOR
Year: 1868

page_text: LETTERS PATENT to James Graham Walker, of Bonnington Steam
Mills, Bonnington, in the County of Mid Lothian, North Britain,
for the Invention of "IMPROVEMENTS IN DRESSING MILLSTONES AND IN
THE MACHINERY OR APPARATUS EMPLOYED THEREFOR."
Sealed the 28th October 1868, and dated the 6th May 1868.
PROVISIONAL SPECIFICATION left by the said James Graham Walker
at the Office of the Commissioners of Patents, with his Petition, on
the 6th May 1868.
I, JAMES GRAHAM WALKER, of Bonnington Steam Mills, Bonnington,
in the County of Mid Lothian, North Britain, do hereby. declare the
nature of the said Invention of "IMPROVEMENTS IN DRESSING MILLSTONES
AND IN THE MACHINERY, OR APPARATUS EMPLOYED THEREFOR," to be as follows,
that is to say:-
This Invention specially relates to an arrangement of mechanism to
be employed in dressing millstones whereby that operation is performed
in a much more rapid and effectual manner than by the means for
effecting it hitherto employed.

page_text: The mechanism consists of a horizontal slide upon which a saddle
travels carrying a cross slide, and to this the cutting mechanism is
attached. The cross slide carries a lever, the outer end of which is
formed into a holder for retaining the tool by which the faces of the
millstones are dressed. At the rear end or part of the slide a revolving
shaft is placed which carries a cam, and a small engine is fixed to the
apparatus by which the shaft is driven, so that by the revolution of the
cam a reciprocating motion in a vertical plane is given to the lever;
and as the tool falls the necessary dressing cut is effected, springs or
weights being placed to act upon the lever, so as to increase the intensity
of the blow. The depth of the cut is regulated by one or more set
screws, and the arrangement of slides placed at right angles enables all
the lines of dressing to be made parallel and similar.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Graham Walker in the Great Seal Patent
Office on the 5th November 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
GRAHAM WALKER, of Bonnington Steam Mills, Bonnington, in the
County of Mid Lothian, North Britain, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of May, in the year of
our Lord One thousand eight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said James Graham Walker, Her special
license that I, the said James Graham Walker, my executors, adminis-
trators, and assigns, or such others as I, the said James Graham
Walker, my executors, administrators, or 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 DRESSING MILLSTONES AND IN THE MACHINERY OR APPARATUS
EMPLOYED THEREFOR," upon the condition (amongst others) that I, the

page_text: said James Graham Walker, by an instrument in writing under my
hand and seal, 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 James Graham Walker, 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, reference being had to the accompanying
Drawings and to the letters and figures marked thereon, that is to
say:-
My said Invention specially relates to an arrangement of mechanism
to be employed in dressing millstones, whereby that operation is per-
formed in a much more rapid and effectual manner than by the means
for effecting it hitherto employed.
The mechanism consists of a horizontal slide upon which a saddle
travels carrying a cross slide, and to this the cutting mechanism is
attached. The cross slide carries a lever, the outer end of which is
formed into a holder for retaining the tool, by which the faces of the
millstones are dressed. At the rear end or part of the slide a revolving
shaft is placed which carries a cam, and a small engine is fixed to the
apparatus by which the shaft is driven, so that by the revolution of the
cam a reciprocating motion in a vertical plane is given to the lever, and
as the tool falls the necessary dressing cut is effected, springs or weights
being placed to act upon the lever so as to increase the intensity of the
blow. The depth of the cut is regulated by one or more set screws and
the arrangement of slides placed at right angles enables all the lines of
dressing to be made parallel and similar.
And in order that my said Invention may be properly understood
I now proceed more particularly to set forth the system, mode, or manner
in or under which the same is or may be used or practically carried into
effect, reference being had for the sake of more complete elucidation to the
accompanying Drawings, and to the letters and figures marked thereon,
that is to say:-

page_text: Figure 1 is a plan, Figure 2 a side elevation, and Figure 3 a
transverse section of a millstone dressing machine according to this
Invention.
The machine consists of a sole plate A, on which there is cast or
fixed a slide B fitted with a compound or double saddle, the under
part C of which serves as a slide for the upper part D, which carries a
small engine E actuated by steam or compressed air for the purpose of
rotating the shaft F; the saddle D also carries a lever G, one end of
which is formed into a holder to receive the dressing tool or pik H; the
other end is situated under the shaft F and actuated by the cams or
wypers a, so as to elevate the ends of the lever carrying the pick H, by
the fall of which the necessary dressing cut is effected; for the purpose
of increasing the intensity of the blow two spiral springs bare fitted on
the columns I under a cross head c, by which they are compressed when
the lever G is actuated by the cams a, and when relieved from the
pressure of the cams the springs 6 expand and force up the end of the
lever, thereby causing the pick H to fall with greater force. In
operating with the machine the compound saddle carrying the dressing
mechanism is traversed to and fro longitudinally by a screw J working
in a nut d, and a transverse motion is given to the upper saddle D by a
screw K working in a nut e. The screw J is operated by a handle L and
the screw K by an index wheel M which is turned by the catches fand g,
these being set so as to move the saddle D in a transverse direction a
distance equal to the space between the grooves in the millstone, and
the depth of these are regulated by the set screw N. The machine is
fastened on the millstone by a spindle or bolt passing through the
centre of the sole plate A.
Having now described the nature of my said Invention, and the
manner in which the same is or may be used or practically carried into
effect, I would observe, in conclusion, that what I consider novel and
original, and therefore claim as the Invention secured to me by the

page_text: Second. The propelling of the lever which carries the pick by means
of a revolving cam and the producing of the blow of the pick lever by
means of a spiral spring, as herein-before described.
In witness whereof I, the said James Graham Walker, have here-
unto set my hand and seal, this Second day of November, One
thousand eight hundred and sixty-eight.
J. G. WALKER. (L.S.)