IMPROVEMENTS IN CUTTING ATTACHMENTS FOR SEWING MACHINES
Year: 1876

page_text: LETTERS PATENT to Lyman Luther Barber, of Boston, in the County of
Suffolk, and State of Massachusetts, U.S. of America, for the Invention of
"IMPROVEMENTS IN CUTTING ATTACHMENTS FOR SEWING MACHINES."
COMPLETE SPECIFICATION filed by the said Lyman Luther Barber at the
Office of the Commissioners of Patents on the 30th June 1876.
LYMAN LUTHER BARBER, of Boston, in the County of Suffolk, and State of
Massachusetts, one of the United States of America. "IMPROVEMENTS IN CUTTING
ATTACHMENTS FOR SEWING MACHINES,"
This my Invention relates to that class of attachments for leather sewing
machines which are operated by the power of the machine, and trim the edges of the
material being sewed in a line parallel with the stitches and simultaneously with
the stitching operation. The Invention has for its object to produce a cutting
attachment of this class, which is adapted to trim and evenly finish edges of any kind
of stock, whether firm or spongy, and of any outline, whether curved, straight, or
tortuous, without interruption; to cut and trim holes isolated from the edge of the
stock without cutting through the same; to be readily disconnected from its driver
and thrown out of and returned to its operative position without being detached
from the machine; and to be adjusted so as to have the wear of its cutting edgo
compensated for. To these ends my Invention consists mainly in a trimming knife
adapted to oscillate or reciprocate in a line substantially parallel with the line of
the feed of the machine, and trim the edge or edges of the stock being stitched in
a line parallel with the row of stitches, the side of the knife working against or in
rubbing contact with the respective edges of the presser foot and a projection on
the throat plate or bed of the machine, these edges being flush with each other and
compressing and holding the stock at the point where it is acted on by the cutter.
The Invention consists in detail in the peculiar form of the knife and the presser
foot, the mechanical means for operating or driving the knife, and the provision of
means for readily disconnecting it from its driver and for adjusting it so as to com-
pensate for the wear of its cutting edge, all of which I will now proceed to de-
scribe.
On the accompanying Drawings Figure 1 represents a plan view of my Invention

page_text: "
as applied to a "Howe sewing machine; Figure 2 represents a section through
line x, x, Fig. 1; Figure 3 represents a section through line y, y, Fig. 1.
Figure 4 represents a plan view of my Invention as applied to a "Singer" sewing
machine; Figure 5 represents a section through line z, z, Fig. 4.
Figure 6 represents a perspective view of the knife and its shank.
Figures 7, 8, 9, and 10 represent modifications of the form of the knife; and
Figures 11, 12, and 13 represent a modification in the manner of operating the knife.
Similar letters of reference in the several Figures refer to like parts.
On the said Drawings A represents the bed of any of the ordinary sewing
machines; C represents the knife or trimmer, which is formed on or attached to
the end of a shank or lever C, this shank resting horizontally on the bed of the
machine, and being pivoted thereto at b. The knife C is preferably formed by
turning up one end of the shank C¹, substantially at right angles with the body of
the shank, and sharpening one edge of this turned portion. The shank C¹ is
adapted to be oscillated on its pivot by connections with the driving shaft of the
machine to be herein-after described, and thus oscillate or reciprocate the knife C in
a line, substantially parallel with the direction of the feed.
J represents the presser foot of the machine, which is so formed on its lower side
as to have only a limited bearing on the stock over the feed and opposite the needle,
like a roll presser (which latter may be used instead if desired) and has an orifice for
the passage of the needle. The presser foot is provided with a flat surface or tread
where it bears on the stock, and back of this tread it is rounded or inclined up-
wardly on the bottom, and cut away or rounded inwardly at the side next to the
knife, for a purpose which will appear herein-after.
Under the presser foot is a projection p, which is formed on the throat plate or
other portion of the bed, and forms a raised bed or bearing for the stock under the
presser foot. The edges of the presser foot and projection, which are adjacent to the
knife or trimmer, are flush with each other, and the knife and its shank are so
located that when the latter is reciprocated one side of it shall work in rubbing
contact with the flush edge of the presser foot and projection. The stock being
stitched and trimmed is held between the presser foot and projection in such position
that when the knife makes a forward movement it will effect a cut in the stock
parallel with the line of stitches being formed, the knife being so adjusted as to
move forward between the movements of the feed, so as not to obstruct the latter,
and while the needle is depressed the shank or strongest part of the needle trans-
fixing the stock and preventing it from being displaced by the horizontal pressure
of the knife. The stock is supported and held on both sides by the flush edges of
the presser foot and projection, and the knife working in rubbing contact with said
edges cuts the stock close to the point where it is supported and held. The lightest
and most spongy stock is thus enabled to be trimmed without being notched or
rendered uneven at the trimmed edge.
The shape of the knife C may vary for different kinds of work; for instance, it
may be straight or curved at its cutting edge, and vertical or inclined, as shown in
Figures 8, 9, and 10. The blade may be formed to cut rounded or other shaped
edges by grooving, beveling, or otherwise forming the edge. One of these modifica-
tions of the blade is shown in Fig. 7, where the blade is grooved on one side, so as
to form a rounded edge.
For general use I prefer to make the outer side of the knife vertical, the cutting
edge notched or shaped, and the back inclined or rounded from the shank C¹ to
the upper end or point of the cutting edge, both the back and edge terminating in this
point, as shown in Figures 6, 9, and 10. This form of cutting edge is best adapted
for trimming and evenly finishing leather which is soft and spongy, like glove
leather or kid, the stock being presented to the knife at the re-entrant angle of its
cutting edge, and compressed by the two inclines, which in moving against the stock
exert an inward pressure from the opposite sides towards the center of the stock,
the latter being thus compressed or turned in at its corners or edges, and prevented
from being burred at the trimmed edge. The rounded back of the knife in connec-

page_text: tion with the rounded bottom and side of the presser foot facilitates the turning of
the stock during the operation, the edge of the stock back of the cutting edge of
the knife sliding easily up the inclined back when the stock is turned from right to
left, the rounded bottom and recessed side of the presser foot leaving a space
between the knife and the presser foot, in which the stock may rise or move freely.
I am thus enabled to trim a sharp angle or an abrupt curve, whether re-entrant
or salient, without liability of unduly stretching or tearing the stock.
Power may be communicated to the shank C¹ and knife C by various mechanical
means, said means varying with the make of the machine.
In Figures 1, 2, and 3 I have shown suitable means for driving the knife from the
shaft I of a "Howe" or other machine having a horizontal main shaft. These
means consist of the following elements, viz. :-A face cam H on the shaft I; a lever
G pivoted to a hanger F¹ on the under side of the bed A, and provided with a stud
and friction roll i, which engages with the groove of the face cam; a slide D,
which is jointed to the upper end of the lever G, and is provided with a pin d,
which projects upwardly through a slot in the bed A, and enters an orifice o in the
end of the shank C¹ opposite the knife C, the slide being supported by a horn or
rest e.
These elements are operated by the rotation of the shaft I in such manner
as to oscillate the shank C' and its knife C in a minute segment, as will be readily
understood. In a "Singer" or other machine having a vertical main shaft, as shown
in Figures 4 and 5, the elements which drive the shank and knife are simply a face
can Land a lever K, the latter being pivoted at 2 to the under side of the bed, and
provided at one end with a stud, which engages with the groove of the face cam,
and at the other with a pin d, which engages with the shank of the knife and
operates it, as before described.
It is often necessary to discontinue the use of the cutter temporarily and stitch
without trimming, as in sewing a strap into a boot or shoe, or in sewing and trim-
ming a second seam after sewing and trimming the edge. To enable this to be done
expeditiously, and without detaching the knife from the bed of the machine, I make
the shank C¹ flexible between its pivot and the end that engages with the pin d of
the driver, and provide this end with an upwardly projecting handle G¹. I am thus
enabled at any time to raise the rear end of the shank so as to disengage it from
the pin d, and turn the shank in its pivot or fulcrum b, so as to throw the knife out
of place and make it inoperative.
If desired the same effect may be produced by adapting the pin d to be de-
pressed below the shank, in which case a spring should be employed to hold the pin
up with a yielding pressure when it is engaged with the shank. Instead of making
the rear end of the shank flexible the shank may be made in two parts, hinged to-
gether, so as to enable the rear end to be raised.
As the cutting edge of the knife becomes worn away by use it is necessary to
move it forward to compensate for the wear and preserve the proper relation of the
cutting edge to the metallic edges against which it works. I have shown two
methods of accomplishing this, one adapted to the class of machines shown in
Figure 1, and the other to the class shown in Figure 4. The former method con-
sists in moving the hanger F¹ transversely with relation to the shaft I (by means of
a slot and a set screw f), thus adjusting the lever G, slide D, pin d, and shank C¹, 80
as to bring the knife C forward. The other method consists in pivoting the shank
C¹ to a plate C³, which is secured to the bed of the machine by a screw I¹ passing
through a slot J¹ in said plate. The plate C2 is adjustable in a line parallel
with the direction of the feed, and is thus adapted to move the shank and knifo
forward.
My Invention is applicable to any ordinary Howe machine, and to any other
popular machine with but little alteration of the machine, the ordinary screw-hole a
of the throat plate B serving to receive the fulcrum 6 of the shank C¹, while the
gage-hole, somewhat elongated, serves to receive the pin d that connects the shank
to the driving mechanism.
The construction and operation of the knife and shank is such as to present no

page_text: obstruction under the arm of the machine to the work, which is consequently
enabled to be turned freely.
My Invention is applicable to so-called wax thread machines, or where a hook or
barb needle and awl are used, as well as to other sewing machines, it being applied
in like manner to be operated by a lever or shaft, and the knife brought near to
work in the side curve of the presser foot, as ordinarily formed for the usual siding
or stitching gage. In this case the knife, oscillating laterally and in a plano
parallel with the work, does not interfere with the thread guide, or the knife may be
hung so as to be oscillated laterally from the arm of a sewing machine, or otherwise
arranged on a sewing machine as preferred to oscillate or reciprocate laterally on the
machine, substantially parallel with the direction of the feed.
A modification of my Invention is shown in Figures 11, 12, and 13, in which the
knife is provided with a short shank, which is rigidly attached to a slide K¹ which
may be an ordinary shuttle cover. This slide is adapted to move in a plane abso-
lutely parallel with the direction of the feed, and is operated by a lever M, which
is pivoted to the under side of the bed A, and is connected with an arm or slide D¹,
which extends through an aperture ordinarily formed in the rim or flange A¹ of
the bed, and is jointed to the lever G, the latter being arranged as before described,
and oscillated by the face cam H, the knife being caused to reciprocate in a direct
line instead of a minute segment of a circle, as when the shank C¹ is oscillated on
a pivot. In either case the result is the same, it being immaterial whether the
knife moves in a straight line and in a plane which is absolutely parallel with
the direction of the feed, as in the modification last described, or in a minute
arc of a circle, which is substantially parallel with the direction of the feed, as first
described.
Having thus fully described the nature, construction, and operation of my Inven-
tion, I wish to secure by Letters Patent and claim,―
1st. A sewing machine knife or trimmer having a cutting edge which projects
upwardly from the bed of the machine, and is adapted to oscillate or reciprocate
in a path substantially parallel with the direction of the feed, substantially as de-
scribed.
2nd. A knife or trimmer C projecting upwardly from the bed of the machine, and
adapted to oscillate or reciprocate in a direction substantially parallel with the
direction of the feed, combined with the presser foot J and projection p, the two
forming flush clamping edges close to and substantially parallel with the path of the
knife, substantially as described.
3rd. The knife or trimmer C formed on or attached to the end of the horizontal
shank or lever C1, and adapted to be oscillated, substantially as described.
4th. The knife or trimmer C having the shaped cutting edge and the rounded
or inclined back, said back and edge terminating at one point, substantially as shown
and described.
5th. The presser foot J rounded upwardly on the bottom and inwardly on the
side back of its tread or bearing surface, combined with the knife C, having the
rounded or inclined back, substantially as described, for the purpose specified.
6th. In combination with the operative mechanism of a sewing machine, a
trimmer constructed substantially as described, and adapted to be swung in a
horizontal plane, into and out of its operative position, and be thereby connected
with or disconnected from its driver, substantially as set forth.
7th. The shank C¹, having the orifice o, combined with the pin d of the driving
mechanism, substantially as described.
8th. The knife C and shank C¹ combined with the pin d and slide D, adapted
to be reciprocated horizontally by the power of the machine, substantially as de-
scribed.
9th. The knife C and shank C¹ combined with the pin d and lever K, adapted
to be oscillated horizontally by the power of the machine, substantially as described.
10th. The shank C¹ of the knife C, combined with the laterally adjustable plate
C², substantially as and for the purpose specified.

page_text: 11th. The laterally adjustable hanger F¹ combined with the lever G, slide D, pin
d, and shank C, substantially as and for the purpose specified.
In witness whereof, I, the said Lyman Luther Barber, have hereunto set my
hand and seal, this Tenth day of June 1876, A.D., at Boston, Massachusetts,
in the U.S. of America.
Witnesses,
CHARLES F. BROWN,
GEO. E. BEATTY.
LYMAN LUTHER BARBER. (LS.)