IMPROVEMENTS IN MACHINERY FOR SHARPENING AND SETTING SAWS
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the Office
of the Commissioners of Patents on the 7th April 1880. A communication
from abroad by George Wilson Dudley and Russel Freedom Way, both of
Waynesboro, Augusta County, State of Virginia, United States of America.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN MACHINERY FOR SHARPENING AND
SETTING SAWS." [A communication from abroad by George Wilson Dudley and
Russel Freedom Way, both of Waynesboro, Augusta County, State of Virginia,
United States of America.]
This Invention relates to a novel construction of saw filing and setting machine
designed especially for saws, having a straight row of teeth, and it comprises
features of improvement as follows-1st. In the peculiar construction and
arrangement of devices for imparting an elastic cutting stroke to the file. 2nd.
Means for raising the file on the back stroke. 3rd. A peculiar construction of
guide for holding the outer end of the file frame against lateral displacement, and
determining the depth of cut. 4th. Means for shifting the angular position of the
saw to give alternate incline to the edge of the teeth. 5th. Clamping and holding
devices for the saw. 6th. Means for adjusting the saw to an angular or straight
position. 7th. Means for locking and holding the saw in position. 8th. The
peculiar construction and arrangement of the saw set. 9th. Means for adapting the
feed wheel to the different sizes of teeth of different saws. 10th. The double
adjustment of the wrist pin connecting with the file driving connection rod, to
adapt the device to longer or shorter files, all as hereinafter fully described.
According to this Invention, the saw carrying devices are arranged between two
parallel bars mounted upon the top of a suitable framework, and having attached to
them a frame projecting horizontally at right angles which carries the file driving
devices, and which will in practice be supported by an additional leg or brace which
may be made to connect with or form a part of the main supporting frame. The
file is of the ordinary 3 corner shape, and is held at its outer end in a rotary
thimble in the pendent right angular end of the file bow, and at its other end is
similarly held in a revolving head arranged upon the outer end of the file bar.
Rising from the end of the file bar is a strap or socket, in which is slid the inner
end of the file bow, which latter is adjustably retained by a set screw so that any
length of file can be accommodated. To allow any one of the edges of the file to
be brought into action, the head is made to revolve, and is provided with bolt

page_text: holes, into which a bolt is forced to hold the file against turning on its axis. By
means of these devices, the ordinary corner file may be adapted to and used with
the machine. To render the pressure of the file on the saw clastic, or to cause it to
have the yielding pressure of the wrist, the file bar has a jointed section, and an
upper and rearwardly extended arın, between which and the jointed section is
interposed a rubber spring which has always a tendency to force the file down
against the saw, and yet causes it to ride over the teeth with a yielding movement.
The file bar has a reciprocating motion imparted to it by means of a connecting
rod which is attached to a wrist pin on a wheel keyed to a horizontal shaft which
is driven from a main shaft, with which it is connected by gearing. The latter
shaft is rotated by a hand crank or by power. In order to raise the file on its
back stroke the-jointed-section of the file bar is provided with guide pieces which
slide in a groove in parallel swinging guide bars which are loosely connected by
links at one end to a cross shaft arranged upon a frame, and at the other end
loosely connected to the lower ends of arms which are rigidly connected to a shaft
also journalled in said frame. On the advance movement of the connecting rod the
swinging guides are at their lowest point to allow the file to rest on the saw, but
on the backward movement the said swinging guide bars are swung upwardly to
allow the file to pass over the teeth of the saw without cutting. To accomplish
this movement, one of the cross shafts of the said bars is provided with a rigid arm
which extends to the driving wheel, and has a friction roller at its end which enters
a cam groove in the side of said wheel. As one portion of the cam groove is farther
from the centre of the wheel than the other portion the travel of the roller therein
causes the arm to rock the shaft, which acting through the rigid arms sustaining
this end of the swinging guide bars gives the lift to the file bar when retreating.
For holding the saw while being operated upon two elongated jaws are
provided. The jaws are pivoted at their ends at a point centrally between the
same to upward projections rising from a support or carriage. To the outer edges
of the jaws are also pivoted links which are also at their lower ends pivoted to each
other, so that by throwing the lower joint of these links upward, the said links act
as toggles to cause the two jaws to clamp the saw. To effect this movement an
angular piece is made to connect with the toggle joint through a slot in the
projection from the carriage, and is bent over the projection and provided with a
set screw.
For opening the jaws the angular piece may be thrown off the projection so as
to unlock the toggle joint, or the same result may be obtained by releasing the set
screws which would allow the piece and toggle joint to descend together. The set
screws at each end are designed mainly however to adapt the jaws to different
thicknesses of saws.
For defining the depth of the cut of the file a right angular piece is secured to
the outer bar of the frame of the machine, and is made to rest upon one of the jaws.
This piece fulfils several functions; first, when the file has cut as deep into the
saw as is required the outer end of the file frame strikes the piece and stops further
cutting action; secondly, by being made grooved upon its upper surface it receives
and guides the outer end of the file frame against lateral displace!nent, ensuring
uniform teeth; thirdly, by abutting against the jaws it acts as a braco to resist
the strain upon the saw carriage caused by the advancing movement of the
file.
In filing the saw every alternate tooth should be filed at a reverse angle, and for
this purpose the position of the saw holding device is changed at every tooth. To
accomplish this result the inner sides of the top bars of the frame are inclined each
way from the middle so as to leave the space between the same diverging each way
from the centre. Between these bars I place a guide frame arranged to oscillate
about a central vertical axis. This guide frame is of rectangular shape and has
grooves upon the inside of its longitudinal bars to receive lugs on the saw carriage,
so that while the saw carriage travels intermittingly in the framo to effect the feed
the said frame is at every tooth swung horizontally into an angular position to the

page_text: file, which is the reverse of that which it maintained for the preceding tooth. In
securing these several movements the oscillating frame is mounted upon a support
which terminates below in a vertical rock shaft stepped or pivoted on a cross bar of
the main supporting frame and held in position by a bearing in a bracket. From
this rock shaft there projects at right angles the rock arm whose outer extremity is
connected by a connecting rod with a disc fixed upon a shaft and receives an
intermittent motion by a pinion and segmental gear on the main crank shaft.
It will thus be seen that through the instrumentality of the connecting rod and
rock arm the guide frame has an intermittent horizontally oscillating movement
which causes the file to cut each tooth at an angle reverse to that immediately
preceding it.
After the saw has been thrown into a position to be cut it is necessary that it
should be firmly held in such position. For this purpose a second disc is fixed
upon the shaft, the same being perforated to receive a spring actuated locking stud
which when the guide frame is at its limit of movement rests in one of the holes of
the disc to lock the parts against further movement. When the position of
the parts is to be shifted again, an offsetting projection on a gear wheel on the
main crank shaft strikes the locking bolt and withdraws it from the perforated
disk, after which the segmental gear effects the movement of the oscillating
frame.
In some cases it is not necessary to give a reversely inclined cut to the alternate
saw teeth, but the filing is required to be down always at right angles, and to this
end the connecting rod of the saw adjusting [device is connected to its disc by a
wrist pin which is adjusted in a slot in said disc. This slot leads through the
centre of the disc so that the wrist pin may be adjusted to a position directly on
the centre of the said disc. When in such position it is obvious that no motion is
communicated to the connecting rod, and the shifting devices are held stationary
with the saw clamping jaws at right angles to the file.
For feeding the saw clamping jaws along as the teeth are successively filed a
toothed rack bar is connected to the bottom of the saw carriage, and a pinion is
made to engage therewith, which pinion is fixed upon a shaft journalled in bearings
beneath the frame and provided with a worm wheel ongaging with a worm on a
shaft at right angles to the first, and an intermittent motion is given to effect the
feed as follows: A pinion is fixed upon the end of the worm shaft, and with this
engages a segmental gear wheel fixed upon the same end of the shaft operating the
saw shifting devices, so that when said shaft is turned the diametrical sets of teeth
on the segmental wheel alternately rotate the worm gear, and through the
instrumentality of the rack and pinion advance the saw with a step by step
movement. To lock the saw at each step of its movement so as to prevent it from
advancing from the action of the file the toothed segments of the wheel are made
sufficiently long, with respect to the segment of its driving wheel, as to cause the
segments to linger in mesh with the pinion at the end of each feed step, and as the
shaft bearing the segmental wheel is locked by the locking devices for the saw
shifter, it is obvious that the saw also is locked at the end of each advance
movement.
For saws of different sizes of teeth a corresponding different range of movement
must be given to the feed, and for this purpose I construct the segmental wheel in
sections placed side by side, which sections have an independent movement on their
common axis, and which are securely held to any adjustment that may be given
them by means of a set screw. The toothed segments of each of these sections are
exactly of the same number and size of teeth, and when all of their teeth are
parallel or in registration the length of the compound segment is at its shortest,
and this adjustment is adapted to the finest toothed saw. When, however, a saw
of larger tooth is to be filed the sections of the segmental wheel are turned one
upon the other so that the length of the segment of the wheel is increased. This
it will be seen gives an increased throw to the feeding devices and allows any
desired adjustment to be obtained. To permit the saw carriage to be run back

page_text: after it has been fed forward as far as it can go, I may use either a spring clutch
for connecting the worm wheel to its shaft, or I may locate the end of said shaft in
a movable bearing, so that the worm wheel may be lifted out of gear with the
worm.
In adapting this machine to different lengths of stroke different lengths of file
are used, and to enable the machine to receive the same a double adjustment of the
connecting rod to the drive wheel is required, first, in order to give an increased
range of stroke the wrist pin which retains the connecting rod is made adjustablo
in a slot in the drive wheel to or from the centre, and as an increased crank throw
is thus provided at one end of the rod and a longer file at tho other it is obvious
that the rod must be shortened in order to cause the file to move from heel to point
over the saw without running over-the-same. I therefore make the wrist pin not
only adjustable in the slot of the drive wheel but adjustable also in a slot of tho
pitman to increase or diminish its length according to circumstances.
For setting the teeth of the saw in the same operation of filing I provide a frame
which embraces the saw clamping jaws and is screwed to the oscillating frame
below. Upon the frame on each side of the path of the saw are hinged_horizontal
seats, which are raised or lowered by set screws at their outer edges. Upon these
binged seats are pivoted the horizontally swivelling setting wheels whose peripheries
are notched to correspond to the desired set, and the notches in which mesh
together, so that when the saw passes between them by the movement of the
carriage a set is given to the teeth alternately in opposite directions. Those
setting wheels are detachable, and a series of the same are provided corresponding
to different sizes of teeth, any of which may be used as circumstances may require.
By tightening the set screws the hinged seats are raised, and the wheels carrying
the same are thrown tighter against the saw teeth to give more or less set, or to
adapt the device to different thicknesses of saw blade.