IMPROVEMENTS IN APPARATUS FOR DRESSING MILISTONES."
Year: 1868

page_text: LETTERS PATENT to Robert Scott, of Edinburgh, in the County of
Mid Lothian, North Britain, for the Invention of "IMPROVEMENTS IN
APPARATUS FOR DRESSING MILISTONES."
PROVISIONAL SPECIFICATION left by the said Robert Scott at the
Office of the Commissioners of Patents, with his Petition, on the
29th April 1868.
I, ROBERT SCOTT, of Edinburgh, in the County of Mid Lothian,
North Britain, do hereby declare the nature of the said Invention of
"IMPROVEMENTS IN APPARATUS FOR DRESSING MILLSTONES," to be as follows,
that is to say :-
This Invention, which relates to an improved arrangement of
mechanism to be used for dressing millstones, consists of a horizontal
bed or table upon which a saddle travels, and which is propelled back-
wards and forwards upon the bed or table by the revolution of a screw
passing through a nut. The saddle carries a cross slide, at one end
of which a perpendicular pillar is fixed carrying the block which con

page_text: stitutes the tool holder, this being movable upwards and downwards
upon the pillar. A cam is so placed that by its revolution it lifts
the tool holder, and as soon as it is out of contact with the holder
the latter falls and the dressing tool or chizel impinges upon the surface
of the stone which is being dressed. To increase the force of the blow
thus struck a spring is applied which presses the tool downwards, and
the pressure produced by the spring is adjustable by means of one
or more set screws. In using the apparatus it is placed on the surface
of the stone about to be dressed, and to increase steadiness is supported
on three legs. The movements necessary for actuating the mechanism
may be produced by manual labour or other motive power.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Scott in the Great Seal Patent Office on
the 28th October 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
SCOTT, of Edinburgh, in the County of Mid Lothian, North Britain,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of April, 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 Robert Scott, Her
special license that I, the said Robert Scott, my executors, adminis-
trators, and assigns, or such others as I, the said Robert Scott, 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 APPARATUS FOR DRESSING MILLSTONES," upon the condition
(amongst others) that I, the said Robert Scott, 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

page_text: 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 Robert Scott, 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, which relates to an improved arrangement of
mechanism to be used for dressing millstones, consists of a horizontal
bed or table upon which a saddle travels, and which is propelled back-
wards and forwards upon the bed or table by the revolution of a screw
passing through a nut. The saddle carries a cross slide, at one end
of which a perpendicular pillar is fixed carrying the block which con-
stitutes the tool holder, this being moveable upwards and downwards
upon the pillar. A cam is so placed that by its revolution it lifts the tool
holder, and as soon as it is out of contact with the holder the latter
falls and the dressing tool or chizel impinges upon the surface of the
stone which is being dressed. To increase the force of the blow thus
struck a spring is applied which presses the tool downwards, and the
pressure produced by the spring is adjustable by means of one or more
set screws. In using the apparatus it is placed on the surface of the
stone about to be dressed, and to increase steadiness is supported on
three legs. The movements necessary for actuating the mechanism may
be produced by manual labour or other motive power.
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 to the accompanying Drawings.
and to the letters and figures marked thereon, that is to say :-
Figure 1 is a side elevation of a millstone dressing machine according
to this Invention; Figure 2 is a front elevation of the machine; and
Figure 3 is a plan of the same; on all the Figures similar parts are
indicated by corresponding letters of reference.
The machine consists of a sole plate A. (shown in elevation in Figures
1 and 2. and in half plan on Figure 3) which is fixed by a bolt or

page_text: spindle B passing through the eye of the millstone C. On each side
of the sole plate A a slot D is formed at any point in which the
slide E. may be fixed, so that the machine may be adjusted to dress
any "quarter" of the stone within the range of the slide E without
changing the position of the sole plate A. The slide E is fitted with
a saddle F, which is moved to and fro longitudinally by the screw H,
and the standard G rests upon and is moved in a transverse direction
by a screw fitted in the saddle F. The vertical bar I to which the
tool holder J is attached slides in the bearings K fixed on the front
of the standards G and is actuated by a three-throw cam L fixed on
the cross shaft M. The amount of lift given to the sliding bar I is
regulated according to the hardness of the stone being dressed by raising
or lowering the stud N in the slot O. The antifriction rollers Pare
formed of leather or other suitable material to deaden the concussion
occasioned by the cam L in lifting the bar I. The force of the blow
given by the fall of the bar I may be adjusted by tempering the
pressure of the spring T by means of the set screw U, and the con-
cussion caused by the fall of the bar I is deadened by an elastic
cushion R against which the horn Q strikes; by this means also the
pick p is prevented from giving a double blow by the recoil of the
bar I. The machine is actuated by a band V passing round the
drum W and the flanged pulleys X, Y. The pulley X is hung upon
a weighted bell-crank lever Z, by which means a uniform degree of
tension on the band V is obtained. The drum W is rotated by a
handle a on the axis of the spur wheel 6 which gears into the pinion c.
The standards d, e, which carry the drum W are bolted to the
flanches f, g, fixed to the slide E.
The mode of operating with the machine is as follows:-The sole
plate A is fixed to the millstone C by the bolt B, and the slide E is set
parallel to the "roads" or grooves in the "quarter" of the stone which
is to be operated upon. The drum W is now revolved by an attendant
turning the handle a, while another attendant turns the screw H by the
handle to cause the pick p to travel across the face of the stone.
When one "road" or groove has been cut the standard G is moved
forward by turning the screw G¹ to the next "road" or groove. In
order that a uniform space may be preserved between the grooves in the
stone a segmental slot bracket j, Figures 1 and 2, is fixed to the back of
the saddle F, in which stop pins i are fitted which regulate the travel of
the handle k which turns the screw G. In dressing certain parts of the

page_text: stone the pick p may be set at an angle by means of the pinching screws 7,
and while the machine is being shifted from one "quarter" to another
of the stone, the sliding bar I is thrown out of gear by pushing
forward the lever m and resting the stud N on the horn n.
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 herein-before in part recited Letters Patent is, the arrangement of
machinery or apparatus for dressing millstones as herein-before described
and shown in the accompanying Drawings, or any merc modification
thereof.
In witness whereof, I, the said Robert Scott, have hereunto set
my hand and seal, this Twenty-fourth day of October, One
thousand eight hundred and sixty-eight.