IMPROVEMENTS IN MACHINERY OR APPARATUS FOR GRINDING SAWS
Year: 1869

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn
-
Fields, in the County of Middlesex, Gentleman, for the Invention
of "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR GRINDING SAWS."-
A communication from abroad by Henry Disston, of Philadelphia,
United States of America
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents, with his Petition, on
the 23rd November 1869.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR GRINDING
SAWS," a communication from abroad by Henry Disston, of Philadelphia,
United States of America, to be as follows:-
This Invention relates to a peculiar combination and arrangement of
machinery or apparatus for grinding saw blades and reducing them to

page_text: the desired taper, so as to leave them thicker at the cutting edge than at
the back, and thinner at the end or point than near the handle.
According to this Invention it is proposed to combine with a grind-
stone a segment having a concave face, against which the blade is held
between two set screws, one of such screws being adjustable by means of
a spring lever for facilitating the fixing and removal of the blade. This
segment receives an up-and-down movement from suitable reversing,
driving, or actuating gear, consisting of pulleys driven alternately by
open and crossed straps shifted as required by being acted upon by
adjustable stops on the segment itself. Four rods are attached, one to
each corner of the segment, and these rods are connected to bosses on a
rocking shaft, which constitutes the centre upon which the segment
moves up and down. The proper angle of the segment for a given
taper of blade is obtained by suitable adjusting nuts on the ends of the
four segment rods. The grindstone is brought up to its work as fast as
it wears by means of two screw spindles, which work through nuts
carried on the sliding bearings which support the grindstone spindle,
and a scroll cam serves to impart a limited to-and-fro, lateral, or end
motion to the grindstone when in operation. A grindstone driver con-
sisting of a number of toothed discs turning on a sliding rod or spindle
is brought into action when required for the purpose of dressing the
surface of the stone, such discs being always brought up to their work
by screw threads formed on the same screw spindles which control the
position of the grindstone, but the pitch of the said threads should be
double that of the threads which act upon the grindstone bearings.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 21st May 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN HENRY
JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of November, in the
year of our Lord One thousand eight hundred and sixty-nine, in the
thirty-third year of Her reign, did, for Herself, Her heirs and successors,

page_text: give and grant unto me, the said John Henry Johnson, Her special
license that I, the said John Henry Johnson, my exccutors, adminis-
trators, and assigns, or such others as I, the said John Henry Johnson,
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 MACHINERY OR APPARATUS FOR GRINDING SAWS," a com-
munication to me from abroad by Henry Disston, of Philadelphia, United
States of America, upon the condition (amongst others) that I, the said
John Henry Johnson, my executors or administrators, 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 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 Henry Johnson, do hereby
declare the nature of the 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 :-
The said Invention relates to a peculiar combination and arrangement
of machinery or apparatus for grinding saw blades and reducing them to
the desired taper, so as to leave them thicker at the cutting edge than.
at the back, and thinner at the end or point than near the handle..
According to this Invention it is proposed to combine with a grind--
stone a segment having a concave face, against which the blade-is-held:
between two set screws, one of such screws being adjustable by means of
a spring lever for facilitating the fixing and removal of the blade. This
segment receives an up-and-down movement from suitable reversing,
driving, or actuating gear, consisting of pulleys driven alternately
by open and crossed straps shifted as required by being acted upon by
adjustable stops on the segment itself. Four rods are attached, one to
cach corner of the segment, and these rods. are connected to bosses on a-
rocking shaft, which constitutes the centre upon which the segment
moves up and down. The proper angle of the segment for a given-

page_text: taper of blade is obtained by suitable adjusting nuts on the ends of the
four segment rods. The grindstone is brought up to its work as fast as
it wears by means of two screw spindles, which work through nuts
carried on the sliding bearings which support the grindstone spindle,
and a scroll cani serves to impart a limited to-and-fro, lateral, or end
motion to the grindstone when in operation. A grindstone dresser con-
sisting of a number of toothed discs turning on a sliding rod or spindle
is brought into action when required for the purpose of dressing the
surface of the stone, such discs being always brought up to their work
by screw threads formed on the same screw spindles which control the
position of the grindstone, but the pitch of the said threads should be
double that of the threads which act upon the grindstone bearings.
And in order that the said Invention may be fully understood I
shall now proceed more particularly to describe the same, and for that
purpose shall refer to the several Figures on the annexed Sheet of
Drawings, the same letters of reference indicating corresponding parts
in all the Figures.
Figure 1 of the Drawings is a side view of the improved saw grinding
machine with one of the frames removed; Figure 2 is a plan view of
Figure 1; Figure 3 is a vertical section of part of the machine taken
along the line 1-2 (Figure 2); Figure 4 is a transverse vertical section.
taken along the line 3-4 (Figure 2); Figure 5 is an inside view of the
segment shewing the saw blade in its proper position; and Figure 6 is
an edge view of the same detached.
A and A' are the opposite side frames of the machine, connected
together at suitable points by the cross bars a, a, a; B is a driving
pulley secured to the shaft C, on which are two loose pullies B¹ and B³,
one on each side of the pulley B, the said shaft C turning in the opposite
frames of the machine. A belt shifter D is arranged to slide in staples b
on the opposite side frames, and is furnished with the usual belt guides.
On the shaft C is a pinion c, which gears into a cog wheel E¹ on a
shaft E, the journals of which revolve in suitable boxes on the opposite
side frames A and A'. On this shaft E is a pulley F, to which is secured
one end of a belt E of gutta percha or other suitable material, the other
and of which is secured to the lower end of the segment G, the latter
being connected to a rock shaft H by the four rods d, d, d, d, and the
centre of this shaft coinciding with the centre of the segment. One end
of each of the rods d passes through a lug e, there being one lug on

page_text: each corner of the segment (see Figure 5). The segment G consists of a
plate strengthened by the ribs g and the end pieces g¹. The saw blade
to be ground is placed against the concave face of the segment G, and is
held securely in its place by the set screws h and h', the latter being
attached to a moveable plate i, which is held in position by the bell-
crank lever i¹, one arm of which is acted on by a spring secured to the
edge of the segment. The projecting ends of the set screws h and h¹
are bevelled to correspond to a bevel made on each end of the saw, so
that however thin the latter may be ground it cannot escape from the
projecting ends of the set screws. On one side of the segment there is
cut a groovej (see Figure 6) adapted to the reception of adjustable
dogs le, k³, and l, and to the dog is hinged an L-shaped catch ³, the
object of which will be rendered apparent hereafter. Passing through
projections 1, ', on the inside of the frame A' is a rod I having two
projections m and m³ (Figure 5), the former of which is inserted into an
opening in the belt shifter D, the end of the other arm m' being so
situated as to be in the range of the dogs / and k³. A. grindstone J is
secured to a shaft J', which turns and is permitted to have a limited end
movement in boxes and n', one end of this shaft having a driving
pulley K, and on the other end a scroll cam wheel L and a pulley L',
which can revolve together independently of the shaft. On the box n¹
there is an arm o having a bent end which projects into the groove of
the scroll cam wheel L. The boxes n and n' are attached to slides on
the opposite side frames of the machine, and have projections with
internal screw threads adapted to those on a shaft N. Each of these
screw shafts turns on a projection q on the frames, and each has a bevel
wheel q' gearing into a similar wheel on a shaft P, which is provided
with a suitable hand wheel I, and which turns in projections on the
ends of the side frames. Q is a stone picker or dresser, consisting of a
series of wheelss which have pointed teeth, and which are hung loosely
upon a stationary spindle Q', and are enclosed in a box or casing situated
in the rear of the grindstone. This spindle passes through guides 8, 8,
which are adjustable one on each frame of the machine, and one end of
the spindle is provided with an appropriate handle t, and is prevented
from turning by a key in one of the adjustable guides fitting into a
groove on the spindle. These adjustable guides are connected to slides
by screw rods u, which are bolted to projections on the said slides R,
there being a nut on each side of the projection, so that the boxes S and
slides R may be adjusted from and towards cach other at pleasure. The
'

page_text: screw shafts N pass through the said projections v, the latter having
internal threads adapted to the threads of the shaft.
The operation of this machine is as follows:-By pressing upon the
long arm of the spring lever ¹ the projecting end of the set screw /³
may be raised sufficiently to allow a saw blade to be laid against the
face of the segment, the lower bevelled end of the screw being inserted
beneath the bevelled projecting end of the set screw h. As soon as thic
saw blade is thus adjusted the pressure upon the lever i¹ is withdrawn,
the pin is depressed by the spring, its bevelled head fitting against the
bevilled end of the saw blade, which is thus securely held between the
two set screws. Two driving belts are used, one crossed and the other
straight, in connection with the pulleys B, B', and B, these belts being
guided by the projections on the shifter D. Supposing the straight
driving belt to be turning the pulley B in the direction of its arrow
(Figure 1), the belt Es must be unwound from the pulley F, and con-
sequently the segment G must move downwards by its own weight in the
are of a circle of which the shaft H is the centre, the saw blade being
subjected to the action of the grindstone during this movement. When
the adjustable dog & comes in contact with and moves the arm m' on the
rod I the arm m will so operate the belt shifter as to transfer the straight
belt on to a loose pulley and the cross belt on to the fast pulley B; hence
the motion of the shaft C must be reversed, and the segment must
commence its upward vibration until the plate & strikes the arm m³,
when the position of the belt will be again reversed and the segment
will descend, and this vibration is continued until the saw has been
completely ground. While the dogs and are used to operate tho
arm m the catch is thrown back, as seen in Figure 6, so as to be
beyond the range of the said arm m³, but should it be necessary to
impart a shorter vibrating movement to the segment G the catch is
moved forward, and serves the purpose of a dog to reverse the movement
of the segment while the latter is rising. When the stone becomes worn
and requires dressing an attendant grasps the handle t of the spindle Q',
and slides the latter backwards and forwards in the guides 8, 8, thereby
causing the sharp teeth of the discs 81, 81, to act on the stone and hack
or dress the same. The screw threads of the portions of the shaft N
which control the position of the stone are one-half the pitch of those
threads of the same shaft which control the position of the dressing
apparatus; hence as the grindstone wears away and is moved by the said

page_text: screw shafts towards the segment G the dressing device is simultaneously
moved, and to such an extent as to be always in a proper position for
acting on the stone.
One of the most important features of this Invention is the mode of
adjusting the segment so that any desired taper may be imparted to the
saw, this adjustment being effected by the nuts f, f, which serve to
secure the outer ends of the rods d to the segment. It will be readily
seen that by the turning of these nuts and thereby altering the position
of the segment in respect to that of the grindstone the saw blade may
be so reduced as to be thicker at the cutting edge than at the back, and
so as to be thicker near the handle than at the end.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used
or carried into effect, I would observe in conclusion that what I consider
to be novel and original, and thereforo claim as the Invention secured
to me by the herein-before in part recited Letters Patent is,-
First. The combination with a grindstone J of a segment G for
holding a saw blade on its concave surface, to which segment a vibrating
motion in the arc of a circle is imparted by the mechanism described, or
any equivalent to the same for the purpose specified.
Second. The combination of the rock shaft H, rods d, d, segment G,
and the nuts ff, or their equivalents for adjusting the said segments on
the rods.
Third. The combination of the reversible pulley F, belt or band E,
and segment G.
Fourth. The combination of the segment, its set screw h, the sliding
piece i, with its set screw ', and spring lever i', the whole being arranged
for the retention and release of the saw blade, substantially as and for the
purpose herein set forth.
Fifth. The combination of the segment G and its adjustable dogs k
and with the devices herein described, or their equivalent, for shifting
the driving belts.
Sixth. The grindstone dresser, composed of a number of discs 81, 8¹,
with pointed teeth adapted to the sliding spindle Q', and operating
substantially as and for the purpose herein set forth.
Seventh. The screw shafts N, N, having threads of different pitches,
those of one pitch controlling the position of the grindstone, and those

page_text: of the other pitch controlling the position of the dressing device, all
substantially in the manner and for the purpose herein set forth.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification, set my hand and scal, this Twentieth day of
May One thousand eight hundred and seventy.
J. HENRY JOHNSON. (L.S.)