IMPROVEMENTS IN FILE CUTTING MACHINES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by the said Paul Ewens at the Office
of the Commissioners of Patents on the 8th February 1883.
PAUL EWENS of Cheltenham in the county of Gloucester " IMPROVEMENTS IN
FILE CUTTING MACHINES
"
For cutting the teeth of files, machines have been employed, constructed and
arranged generally as follows. A longitudinally sliding bed carrying the filo
blank is advanced gradually under a chisel which is raised in opposition to a
spring by a cam, and suddenly let go, so that it strikes the blank, and thus cuts
tooth after tooth of the file as the blank advances.
My invention relates to improvements in machines of this kind whereby I
obtain greater simplicity and uniformity of action and facilities for varying the
cut applied to different files and to different parts of the same file. I make the
bed of a section somewhat more than a semicircle and fit it to slide in a trough
guide of corresponding form, which trough is mounted on a vertical axis, so that
the bed can be turned to various angles horizontally so as to cut obliquely the
blank fixed upon it. I hold the blank in position by engaging its tang between
two roughened cheeks hinged upon the bed in such manner that a strain applied
to withdraw the tang from between them, causes them to grasp it more tightly.
In order to release the tang, I make the hinge pin of one of these cheeks eccentric
so that it can be turned into such a position as to withdraw the cheek. The
blank is held down on the bed by rollers of wood or other suitable material,
which rollers are mounted on levers that are pressed by weights or springs, and
can be released when the blank is to be removed. Above and across the bed is
mounted, in stationary bearings, the main shaft of the machine which is caused to
revolve by any convenient motor. On this shaft is fixed the cam, which, as the
shaft revolves, raises, in opposition to a spring, the box holding the chisel and, at
a certain point in its revolution, releases the box, permitting the spring to force
it down so that the chisel strikes the blank and cuts the tooth of the file. The cam

page_text: for this purpose, instead of being single, acting once in a revolution, may have
three or more protuberances, so as to act three or more times in a revolution.
The chisel box with its connection is guided in a frame which can be turned
round the shaft as an axis, and can be set in various attitudes, thus directing
the stroke of the chisel more or less obliquely on the blank. The force of
the spring can be a little varied by an adjusting screw, but as this force
requires to be considerably less when the chisel is cutting the narrower parts of
the file, I connect a clamp box attached to the spring to the link of an eccentric
which is turned partly round step by step by-ratchet and pawl or equivalent
mechanism, while the blank moves under the chisel, so as to increase or diminish
the force of the spring according as a wider or narrower part of the blank is
presented for the blow. For the purpose of advancing the blank, I provide a
feed screw working in a half or divided nut attached to the bed and I cause this
screw to turn step by step by means of a ratchet and pawl operated by levers
worked by a cam on a secondary shaft, which is geared by change wheels to the
main shaft, so that, according to the gearing selected the gauge of tooth may be
varied as desired. The feed levers and gearing are so arranged as to allow for
-the bed being turned towards various angles horizontally as above described. For
-bringing back the bed, the divided nut is disengaged from the screw, so that the
bed can be rapidly drawn along its guide.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Paul Ewens in the Great. Seal Patent Office on the 8th August
1883.
PAUL EWENS of Cheltenham in the County of Gloucester
FILE CUTTING MACHINES
"
"IMPROVEMENTS IN
For cutting the teeth of files, machines have been employed constructed and
arranged generally as follows. A longitudinally sliding bed carrying the file,
blank is advanced gradually, under a chisel which is raised in opposition to a
spring by a cam, and suddenly, let go so that it strikes the blank and thus cuts
tooth after tooth of the file as the blank advances. My invention relates to
improvements in machines of this kind, whereby I obtain greater simplicity and
uniformity of action and facilities for varying the cut applied to different files and
to different parts of the same file. I make the bed of a section somewhat more
than a semicircle and fit it to slide in a trough guide of corresponding form,
which trough is mounted on a vertical axis so that the bed can be turned to
various angles horizontally so as to cut obliquely the blank fixed upon it. I hold
the blank in position by engaging its tang between two roughened cheeks hinged
upon the bed in such manner that a strain applied to withdraw the tang from
between them causes them to grasp it more tightly
In order to release the tang, I make the hinge pin of one of these cheeks
eccentric, so that it can be turned into such a position as to withdraw the cheek.
The blank is held down on the bed by rollers of wood or other suitable material,
which rollers are mounted on levers that are pressed by weights or springs, and
can be released when the blank is to be removed. Above and across the bed is
mounted in stationary bearings the main shaft of the machine which is caused to
revolve by any convenient motor. On this shaft is fixed the cam, which, as the
shaft revolves, raises in opposition to a spring the box holding the chisel, and at a
certain point in its revolution, releases the box, permitting the spring to force it
down so that the chisel strikes the blank and cuts a tooth of the file. The cam
for this purpose, instead of being single, acting once in a revolution, may have
three or more protuberances, so as to act three or more times in a revolution.
The chisel box with its connections is guided in a frame which can be turned
round the shaft as an axis and can be set in various attitudes, thus directing the
stroke of the chisel more or less obliquely on the blank. The force of the spring
can be a little varied by an adjusting screw, but as this force requires to be con-
siderably less when the chisel is cutting the narrower parts of the file, I connect
a clamp box attached to the spring to the link of an eccentric which is turned
partly round step by step by ratchet and pawl'or equivalent mechanism while the
blank moves under the chisel, so as to increase or diminish the force of the spring
according as a wider or narrower part of the blank is presented for the blow.
For the purpose of advancing the blank, I provide a feed screw working in a half
or divided nut attached to the bed and I cause this screw to turn step by step by
means of a ratchet and pawl operated by levers worked by a cam on a secondary
shaft which is geared by change wheels to the main shaft, so that according to the
gearing selected, the gauge of tooth may be varied as desired. The feed levers and
gearing are so arranged as to allow for the bed being turned to various angles
horizontally, as above described. For bringing, back the bed, the divided nut is
disengaged from the screw, so that the bed can be rapidly, drawn along its
guide.

page_text: DESCRIPTION OF THE DRAWINGS
Fig 1 is a side elevation, Fig. 2 is an end elevation, and fig. 3 is a plan of a file
cutting machine embodying my improvements; Fig. 4 is a side view and Fig. 5 is
a section, and fig. 6 is a front view of the chisel box and the mechanism for
working it; fig. 7 is a front view and fig. 8 a side view of the clamp box and
eccentric for varying the force of the spring; fig. 9 is a section of the circular bed
and trough in which it is fitted with the mechanism for varying its inclination;
fig. 10 also shews in section the circular bed and trough and the rollers for holding
down the blank; Fig 11 is a plan of the same; Fig. 12 is a side view and fig. 13 a
plan of the cheeks for holding the tang of the file blank. In all these figures the
letters of reference indicate similar parts. A is the main shaft of the machine, on
which is fixed the cam B which in fig. 5 is shewn to have three protuberances, so
as to effect three cuts in each revolution of the main shaft. Each protuberance acts
successively on the shoulder of the chisel box C so as to raise it in opposition to the
spring D, which, when the cam escapes, forces the box and the chisel down so as to
effect the cut. The chisel box C is fitted to slide in a frame or cradle E which can
be turned more or less round the shaft A as an axis, as indicated by the dotted
lines in fig. 4, the direction of the blow of the chisel being thus varied. The
cradle E, when set, is held in position by bolts passed through slotted holes e in
stationary side cheeks F formed on the bearings of the shaft A. The spring passes
through a clamp box G and can be strained therein more or less by a screw g; but
the clamp box itself has an eye embracing an eccentric H fixed upon a spindle h on
which is a ratchet segment I. On the main shaft A is fixed a tooth cam i which,
when the ratchet teeth of I are presented towards it, moves these one by one as
the shaft revolves, so lowering the clamp box G step by step, and farther straining
the spring D as the cuts of the chisel take effect on a broader part of the file blank.
The bed K on wbich the file blank is laid to be cut is of cylindrical form, fitting in
the trough L, so that by means of the setting screw k and the spring k¹ it can be
canted a little to one side or the other, so as to bring the surface of the file blank
level to receive the cut of the chisel. As the bed K travels to and fro along the
trough L, the screw k and spring kl are provided with antifriction rollers, as shewn
in fig. 9. The file blank to be cut has its tang T. inserted between the roughened
cheeks M which are pivotted on the bed and pressed towards each other by an
elastic band m, so that any effort of the tang to withdraw itself causes the cheeks M
to grasp it more firmly. One of the cheeks M is pivotted on an eccentric pin
which can be turned by a handle so as rapidly to withdraw the cheek and release
the tang T. The body of the blank is held down by rollers N mounted on levers
which are pivotted on the sides of the trough L. Under the short ends of the
levers are inclined springs P fitted to be slid along the trough L by means of
screws p. On turning these screws in one direction by turning a wheel O to which
both of them are geared, the inclined springs P can be advanced under the short
arms of the roller levers so as to cause the rollers to bear tightly down on the blank
beneath them. On reversing the screws p, the pressure of the rollers N on the file
is relieved, so that the file can be withdrawn.
The movement of the bed K is effected by means of a screw working in a part
nut fixed to the bed K. This screw is moved by bevil gear R from a spindle
and ratchet wheel S worked by a pawl moved by an eccentric on a countershaft U,
The arm connecting the eccentric strap to the pawl lever is made with a joint at u
so that when the trough L is turned more or less round on the foundation of the
machine the connection to the feed ratchet may be maintained.
Having thus described the nature of my invention and in what manner the
same is to be performed, I claim as my improvements in file cutting machines-
"
First: The combination of roughened pivotted cheeks for holding the tang of the
file blank with rollers for pressing down the body of the blank and their levers and
inclined springs, substantially as herein described.

page_text: Second Fitting the chisel box in a frame or cradle which can be turned more or
less round the main shaft, substantially as and for the purposes herein set forth.
Third: The combination of the clamp box for the spring, and its eccentric and
ratchet segment with the toothed cam, for varying step by step the force of the
spring, substantially as herein described.
Fourth: The herein described gear for working the feed screw, admitting of the
turning of the bed to various angles.
In Witness whereof I the said Paul Ewens have hereunto set my hand and
seal this fourth day of August in the year of our Lord, One thousand, eight hundred
and eighty-three.