Improve- MENTS IN APPARATUS FOR GRINDING AND POLISHING CIRCULAR SAWS AND KNIVES OR DISCS OF METAL
Year: 1871

page_text: LETTERS PATENT to John Wilkinson, of Bethnal Green Road, in the
County of Middlesex, Saw Maker, for the Invention of “Improve-
MENTS IN APPARATUS FOR GRINDING AND POLISHING CIRCULAR SAWS AND
KNIVES OR DISCS OF METAL."
Sealed the 18th August 1871, and dated the 24th February 1871.
PROVISIONAL SPECIFICATION left by the said John Wilkinson at the
Office of the Commissioners of Patents, with his Petition, on the
24th February 1871.
I, JOHN WILKINSON, of Bethnal Green Road, in the County of
Middlesex, Saw Maker, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN APPARATUS FOR GRINDING AND POLISHING
CIRCULAR SAWS AND KNIVES OR DISCS OF METAL," to be as follows:-
--
My Invention relates to an improved arrangement of apparatus for
grinding and polishing circular saws, and circular knives or discs of
metal, by which the grinding operation may be regulated with great
accuracy.

page_text: The chief feature of my Invention consists in so disposing the stone
or grinding wheel in relation to the surface to be ground that the portion
of the stone or wheel, which is in contact with or is acting on said
surface, shall always move by the rotation of the stone or wheel radially
towards or away from the centre of said saw or disc, whereby unequal
wear of the grinding surface is avoided.
-
In carrying out my Invention, I secure the saw or disc as usual
against a chuck or flat face plate attached to the rotating head of a lathe.
The grinding or polishing is performed by a grindstone or emery (or
other) wheel, which is fitted on a spindle, mounted to rotate in a suitable
slide rest. This slide rest is made in two parts, the upper one in which
the grinding stone or wheel is mounted being capable of moving over
the lower part to or from the surface to be ground, against which the
stone or wheel is maintained by means of springs or counterweights.
The upper part of the slide rest (which may be made capable of adjust-
ment according to the diameter of the stone) is fitted with a friction
roller, which is also kept up against a fixed stop or guage by the force
of the springs, this gunge serving to regulate the grinding, and so
determine the form to which the surface is to be reduced or ground.
For this purpose the surface of the stop or guage is made of the exact
form to which it is desired to bring the surface of the saw or disc, that
is to say, it is made to correspond to a radial section of a saw or disc
of the desired form, which may either be a flat or bevelled convex,
concave, or dished surface. By traversing the slide rest the grinding
stone or wheel is caused to operate on a zone of the surface to be ground
nearer to or farther from the centre, and the friction roller is also caused
by the same movement of the slide rest to travel along the shaped
surface of the guide or pattern against which it is maintained by the
springs as before mentioned or by counterweights. The grinding stone
or wheel is thus caused to follow the line or surface of the guage or
pattern, and reproduce the form of the same on the surface of the saw
or disc, which may thus be accurately ground to any required pattern
and of uniform thickness. Power may be applied by band or other
gearing to rotate both the chuck carrying the disc to be ground and
the grinding stone or wheel.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Wilkinson in the Great Seal Patent Office
on the 24th August 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
WILKINSON, of Bethnal Green Road, in the County of Middlesex, Saw
Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fourth day of February, in the
year of our Lord One thousand eight hundred and seventy-one, in the
thirty-fourth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Wilkinson, Her special licence,
that I, the said John Wilkinson, my executors, administrators, and
assigns, or such others as I, the said John Wilkinson, 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, usc, 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 GRINDING AND POLISHING CIRCULAR SAWS AND KNIVES OR DISCS OF METAL,"
upon the condition (amongst others) that I, the said John Wilkinson,
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 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 John Wilkinson, 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 Sheet of Drawings
hereunto annexed, and to the letters and figures marked thereon (that
is to say):
My Invention relates to an improved arrangement of apparatus for
grinding or surfacing saws and circular knives or discs of metal, by
which the grinding operation may be regulated with great accuracy.
The chief feature of my Invention consists in so disposing the stone
or grinding wheel in relation to the surface to be ground that the

page_text: portion of the stone or wheel which is in contact with or is acting on
said surface shall always move by the rotation of the stone or wheel
radially towards or away from the centre of said saw or disc, whereby
unequal wear of the grinding surface is avoided.
In carrying out my Invention I secure the saw or dise as usual against
a chuck or flat face plate attached to the rotating head of a lathe. The
grinding or polishing is performed by a grindstone or emery (or other)
wheel, which is fitted on a spindle mounted to rotate in a suitable slide
rest. This slide rost consists of two principal parts, the upper one in
which the grinding stone or wheel is mounted being capable of moving
over the lower part to or from the surface to be ground, against which
the stone or wheel is maintained by means of springs or counterweights.
This upper part of the slide rest (which may be made in two portions so
as to be capable of adjustment according to the diameter of the stone)
is fitted with a friction roller which is also kept up against a fixed stop
or guage by the force of the springs or weights, this guage serving to
regulate the grinding, and so determine the form to which the surface
is to be reduced or ground. For this purpose the surface of the guage
is made of the exact form to which it is desired to bring the surface of
the saw or disc, that is to say, it is made to correspond to a radial section
of a saw or disc of the desired form, which may either be a flat, bevelled,
convex, concave, or dished surface. By traversing the slide rest the
grinding stone or wheel is caused to operate on a zone of the surface to
be ground nearer to or further from the centre, and the friction roller is
also caused by the same movement of the slide rest to travel along the
shaped surface of the guide or pattern against which it is maintained by
the springs or weights, as before mentioned. The grinding stone or
wheel is thus caused to follow the line or surface of the guage or pattern
and reproduce the form of the same on the surface of the saw or disc,
which may thus be accurately ground to any required pattern and of
uniform thickness. Power may be applied by band or other gearing to
rotate both the chuck carrying the disc to be ground and the grinding

page_text: rest B, to which stone rapid rotary motion is imparted by bevel gearing
from shaft C also mounted in B, and driven by band gearing from an over-
head shaft. The stone or wheel A, whether placed horizontally as
shown, or otherwise, must in any case be so disposed in relation to the
surface to be ground or polished that the spindle of the stone or wheel
shall be both parallel with said surface and at right angles to a radial
line drawn from the centre of the saw or surface through the point of
contact with the periphery of the stone or wheel; or in other words, so
that the portion of the periphery of the stone or wheel in contact with
the surface to be ground shall always move radially towards or away
from the centre of the said surface. D is the saw or metal disc the surface
of which is to be ground or polished. It is firmly secured or clamped
by a central bolt and plate to a chuck in the form of a flat face plate E,
attached to the spindle 1 mounted to rotate in bearings in a fixed
headstock G rising from the bed H of the machine and driven by band
gearing through the medium of fast and loose pulleys H³ or preferably
by a worm shaft gearing with a worm wheel on spindle F. Slow rotary
motion is thus imparted to the saw or disc D so as to continually present
a fresh surface to the stone as the grinding or polishing progresses. The
slide rest B consists of two principal parts B and K, the upper part
being made in two portions B and B' fitted or dovetailed together so
as to be capable of adjustment by means of a screw bolt I working
through a collar fixed to an extension in rear of B' and received in a
corresponding nut fitted into a hole at the rear end of part B, so that
the latter may be set permanently nearer to or further from the surface
of the saw D according to the diameter of the stone A, the screw I being
operated by a turning key or handle fitted on its squared end. The
part B' is fitted in guides in K which consists of a rectangular frame in
which the part B, B', is capable of being slid bodily towards and from
the saw or disc D. A friction or guide roller L is mounted on B¹ at the
end nearest the face plate E, which roller is caused to work against a
fixed guide or templet M, being maintained against the same by strong
metal springs N in frame K bearing against the rear end of the slide
rest B, B¹, carrying the stone A which is thus kept up to its work by
the pressure of said springs. This templet M is an exemplar or pattern
of the exact form to which it is desired to reduce the surface of the saw
or disc, its edge, against which the roller L works, being straight,
inclined, or curved (convex or concave) according as the surface of the
-saw is to be plane, bevelled, convex, or concave. The slide or frame Ķ

page_text: is supported on an elevated bed or platform O, placed parallel to the
surface of the saw D and upon which the grinding or polishing apparatus
is capable of being traversed across the face of the saw or disc, thereby
causing the stone A to act on a zone of its surface nearer to the centre or
to the circumference, as the case may be. In this traversing movement
the roller L runs along the curved or other face of the templet M and so
guides the stone A as to reproduce the form of the pattern on the
surface of the saw or disc, which is thereby ground with the greatest
accuracy. The templet M is secured by screw bolts and nuts P to a
fixed standard or support R placed in front of the plate E. The bolts P
pass through slots in the templet or guage M to admit of the latter
being adjusted by means of set screws S so as to regulate the thickness
of the saw with the greatest nicety. In order to admit of this adjust-
ment of the pattern M it is necessary to remove the pressure of the
springs N which is effected by means of a screw Z working through
a collar in the end of frame K into a nut fixed in the end of B',
whereby the springs may be compressed. The platform O has bevelled
edges which are accurately planed and fitted into corresponding slides
on the under side of frame K, so as to permit of the grinding apparatus
being freely traversed as before described and yet maintained at all
times equally up to its work, either by the pressure of the springs as
shown, or by counterweights.
The traverse of the grinding apparatus may bo effected automatically,
and at a slow speed by means of a guide screw Q, mounted beneath
the platform of O and extending from one side of the machine to the
other beneath the slide rest B and working in a screw box or nut Q'
fixed to tho under side of frame K. This shaft is driven alternately in
either direction by bevel gear from a vertical shaft T operated from a
horizontal shaft U provided with reversing gear V actuated by means
of a lever W pivoted at W¹ and weighted, as shown, to ensure its prompt
action, said lever being thrown over to the ono side or the other by a
sliding rod X moving in fixed guides on bed O, and operated by a
projecting lug on the slido rest K itself, which, when it arrives at either
end of its traverse comes in contact with an adjustable scrow collar X'
on rod X, and throws over the lever W to the other side. By fixing
the collar X' less or farther apart the extent of traverse and consequently
the amount of surface acted upon by the stone or wheel A can be
limited as desired. Shaft U is driven by bevel gear from another

page_text: shaft Y which is rotated at a reduced speed by means of a train of spur
gearing, as shown, from the main or driving shaft F.
Having described the nature of my Invention, and the manner of
performing the same, I declare that what I claim as my Invention
to be protected by the herein-before in part recited Letters Patent
is,—
1st. In machines such as those above described I claim applying the
grindstone or polishing or grinding wheel to the surface of the saw or
disc, so as to grind or work in a radial direction thereon as herein-
before described and illustrated in tho Drawings and for the purpose
specified.
2ndly. I claim the use of a templet or pattern for regulating and
guiding the grinding apparatus in combination with springs or weights
to maintain the said apparatus against the templet and up to its work
against the surface to be ground substantially as herein-before set forth
and shown in the Drawings.
In witness whereof, I, the said John Wilkinson, have hereunto
set my hand and scal, this Twenty-third day of August, in
the year of our Lord One thousand eight hundred and seventy-
onc.