Improvements in Hem-stitch Sewing Machines.
Year: 1899

page_text: Date of Application, 23rd Aug., 1899-Accepted, 9th Dec., 1899
[Communicated from abroad by THE SINGER MANUFACTURING COMPANY, of New
York, United States of America, Sewing Machine Manufacturers.]
Improvements in Hem-stitch Sewing Machines.
I, JOHN KING MACDONALD, Manager of The Singer Manufacturing Company,
Kilbowie, Dumbartonshire, do hereby declare the nature of this invention and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
This invention relates to a machine for doing that class of hem-stitch work
known as "spoke-stitching" and in which two lines of stitches are formed, one
at each side of the row of openings forming the hem-stitch work; the object
of the invention being to provide a strong and durable machine, for doing the
class of work referred to, which is simple in construction and which is adapted
for rapid operation.
In the accompanying drawings Fig. 1 is a side view, partly in vertical section,
of the improved machine, and Fig. 1 is a detail view of a part of the operating
mechanism of the thread-dividing spur. Fig. 2 is a bottom view of the machine.
Fig. 3 is a detail plan or top view of the cam for operating the thread-dividing
spur. Fig. 4 is a front end view of the machine, partly in section and with
the face-plate removed. Figs. 5 and 6 are detail views, from opposite sides
of the needle-carriers and connected parts, the thread-dividing spur also being
shown. Fig. 7 shows the block or cross-head attached to the lower end of the
needle-bar and in which the needle-carriers are pivotally mounted. Fig. 8 is
a detail view of the needle-carriers removed from said block. Fig. 9 is an
enlarged cross-section of the thread-dividing spur and needles, with the latter
closed against said spur and Fig. 10 is a detail plan view of the thread-dividing
spur and the arm on which it is formed.
A denotes the work-plate and B the bracket-arm of a sewing machine which,
in its general construction, is that of one of the well-known styles of Singer
machines, and which need not therefore, be very particularly described. C is
the driving-shaft journalled in the upper part of the arm B and having, as
usual, at its forward end a crank connected by a pitman & to the needle-bar D).
The shaft C is provided near its rear end with a bevel gear c meshing with a
similar bevel gear e at the upper end of a vertical shaft E journalled in the
vertical portion of the arm B and carrying at its lower end a crank-disc e¹2
connected by a pitman el to an arm e² of a rock-shaft e³ having a second arm e
engaging a crank-arm on the shuttle-operating rock-shaft e carrying the
shuttle driver e to operate the oscillating shuttles 8. This shuttle-operating
nechanism is that of the well-known Singer overseaming machine excepting
that in the present instance two closely placed shuttles are employed instead
of one, as heretofore, in this style of machine.
The shaft E is provided, beneath the work-plate, with a gear-wheel e meshing
with a larger gear-wheel F journalled on the stud F and which performs one
otation to three rotations of the shaft E and of the driving shaft C, said gear-

page_text: wheel F being provided with a cam groove f¹ entered by a pin or roller-stud fª
carried by one arm of a bell-crank lever f³ the other arm of which engages
the feed lever f pivoted on an adjustable fulcrum f with which the feed-
regulating bar f is provided; the feed-dog f being attached to or connected
with the forward end of said feed lever in the usual or any well-known manner.
The crank-disc e2 is provided in its upper face with a cam groove 9 entered
by a pin or roller-stud carried by one arm of a bell-crank lever G to the other
arm of which is jointed the rear end of a pitman g' connected at its forward
end to a lever 3 pivoted in a projection or bracket on the shuttle race *.
The forward end of the lever extends beneath a vertically reciprocating rod g
having an arm or offset portion g6 at its upper end and which arm or offset por-
tion is provided with the thread-dividing prong or spur g. The rod g³ is pre-
ferably forced downward by a coil-spring 98 interposed between a portion of
the shuttle race (in which the bearing for said rod is formed) and the milled
head of a screw tapped in the lower end of said rod. A slight adjustment
between the rod 95 and its operating lever g is preferably provided by means
of the screw 912 against a head on the upper end of which the abutting milled
head rests. This adjustment permits of a slight variation, vertically, of
the spur g to bring it into proper operating position relative to the other
parts, or to compensate for any slight differences of construction, should such
occur in different machines. The arm or offset part go of the rod is formed
as a thin blade and is arranged between the two shuttles so that said arm and
the spur g serve partly as a thread separator between the two needles and
shuttles, the small depending fin or rib m on the plate m¹ also serving partly
as a thread separator. The spur g' is recessed for the reception of the needles,
when the latter are closed together as shown more clearly in Fig. 9. Fig. 1
represents the arm or part 96, with its spur, in front of one of the shuttles es,
the other shuttle (which would occupy a position in front of or toward the
observer from said arm g) being removed.
The shaft C is provided with a bevel gear c¹ meshing with a larger bevel
gear with which the cam-disc H is provided, these gears being so proportioned
that the said cam-disc makes one revolution to each three revolutions of the
driving shaft. The cam groove h of the disc H is entered by a pin or roller-
stud at or near the upper end of a lever h² pivoted at h³ to the bracket-arm B.
said lever being provided with a groove which receives an adjustable slide at
the rear end of the pitman h, said slide being secured in any desired position
of adjustment, in the usual manner, by the thumb-nut h. The pitman his
connected at its forward end to a lug or projection i on a swinging frame I
pivoted in the head 6 of the bracket-arm on the centre-screws b¹. The swinging
frame I is provided with a vertical rod on which is fitted a slide having a
stud entering a head of an arm attached by a screw to the pivoted needle-
carrier, said needle-carrier having a notch or slot entered by a tooth or pro-
jection with which a second pivoted needle-carrier is provided. The
needle-carriers, (to which the needles are secured by set screws (³) are
formed with pivot studs entering bearings in a block or cross-head d
attached to the lower end of the needle-bar D; said carriers being secured in
their bearings in said block or cross-head by screws 8. The tooth or projec-
tion is preferably formed on a small plate & (shewn at Fig. 6,) adjustably
secured to the needle-carrier ³, so that by a slight change of position of said
tooth, when necessary, the vibrating positions of the needles may be equalized
so that they will both have the same degree of inclination when their points
are closed against the thread-dividing spur g7.
Attached to the block or cross-head, by a screw k, is a small bracket or
plate provided at its lower end with a socket for the reception of an awl
or pricker having a bent or offset shank portion, the said awl or pricker being
held in its socket by the set-screw 3. The lower or working portion of the
said awl or pricker is arranged in front (in the line of the feed of the work)

page_text: of the thread-dividing prong or spur g a distance just equal to the length of
the movement of the work by the feed. If the length of the feed be varied
the position of the working portion of the awl or pricker can be varied to cor-
respond by loosening the set screw slightly and turning the said awl or
pricker in its socket, the cranked or offset portion of the shank of the said
awl or pricker permitting the working portion thereof to be swung towards
and from the vertical plane of reciprocation of the thread-dividing spur with-
out appreciably disturbing the alignment of the said working portion of the
said awl or pricker with said spur. The awl or pricker serves, as will be
understood, as an initial thread-divider to form holes in the fabrics and which
holes will be entered and enlarged, after the next feeding movement of the
work, by the thread-dividing spur 97 previous to the entrance of the needles.
This awl or pricker, although a desirable feature of the improved machine,
is not indispensable in the successful operation thereof, and might, therefore,
be omitted without departing from the essence of the invention.
From the connection of the needle-carriers &, ³, with the grooved cam h,
as hereinbefore described, it will be apparent that said needle-carriers will be
vibrated (through the lever h², pitman h, swinging frame I and arm 5, which
arm is connected through the slide 3 to the rod 2 carried by said swinging
frame) to move the needles from and towards each other to the separated and
closed positions shown by full and dotted lines, respectively, in Figs. 5 and 6.
As the cam-disc H performs one revolution to each three revolutions of the
driving shaft, and consequently to each three vertical reciprocations of the
needles and each three oscillations of the shuttles, the needle-carriers will be
vibrated once to every three stitches formed by each needle and shuttle. The
grooved cam h is so formed that the needles will be in their separated positions
in making one stitch and in their closed positions when making two stitches.
Owing to the geared connection herein before described of the feed cam-wheel F
with the driving shaft it will be understood that the feed-dog will, in the pre-
sent machine, be operated to feed the work once for each three stitches, or once
for each three vertical reciprocations of the needle-bar; and this feeding move-
ment is, in this machine, timed to occur between the two reciprocations of the
needle-bar performed when the needles are in their closed positions. A differ-
ently timed feed might, however, be employed, as, for example, an ordinary hem-
stitch feed, which moves the work forward twice and backward once, and thus
a different "spoke-stitch" seam might be formed, without otherwise changing
the machine.
The thread-dividing spur, which is arranged adjacent to the vertical paths
of the needles when the latter are in their closed positions, performs one recipro-
cation at each vertical reciprocation of the needles, and is so timed as to rise
through the work as the needles are descending so that its point will be above
the work before the points of the needles enter the latter, and thus when the
needles are in their closed positions they will be partly housed in and thus
guided by the recesses or grooves formed in the opposite sides of said spur for
their reception, the said spur descending, before the needles rise, so as to leave
the hole in the fabric free for the drawing of the needle threads when the
shuttles are expanding the needle loops and so that said spur will be disengaged
from the work when the latter is fed.
When the thread-dividing spur rises it passes upward in the hole which has
been preferably previously made by the awl or pricker, the hole being enlarged
and the divided threads being held apart by the said spur and by the needles
while the stitches are being formed, the threads of the stitches which pass
through the holes in the work, or between the divided threads of the fabrics,
being anchored into the body of the fabrics when the needles descend in their
separated positions.
The work performed by the improved machine is similar to that made in the
machine shown in U.S. Patent to Gegauf, No. 592,088, dated Oct. 19, 1897, as

page_text: "
illustrated in Figs. 5 and 6 of the drawings of said patent. In the use of the
Gegauf machine, however, only straight, or approximately straight, hem-stitch
or spoke-stitch seams can be made, owing to the fact that the needles are
arranged one behind the other in the line of the feed of the work, and conse-
quently sharp corners cannot be turned, as is necessary, for example, in hem-
stitching handkerchiefs, square tidies, etc., as can be done with the improved
machine herein described. It has been found, moreover, that by arranging the
thread-dividing spur beneath the throat-plate or work-plate a more convenient
and more reliably operating mechanism is provided, in that said spur does not
interfere with the needles to prevent the proper running of the needle threads
as the latter are drawn down by the shuttles, and said spur also serves to guide
the needles as they descend; and by constructing the machine with a simple
and positively operated needle-vibrating mechanism higher speed and more
durability are attained than with the Gegauf construction. The invention,
therefore, is not to be understood as being limited to the details herein shown
and described, as these may be varied widely without departing from the spirit
of the invention.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. In a sewing machine the combination with a needle-bar and its operating
mechanism, of two needle-carriers movably connected with said bar and pro-
vided with needles, mechanism for operating said carriers to move the said
needles from and towards each other, loop-taking devices co-operating with
said needles, a thread-dividing spur arranged beneath the work-plate of the
machine and adjacent to the paths of descent of said needles, means for operat-
ing said spur to cause it to rise through the work before the descending needles
enter the latter, an awl or pricker arranged above the work-plate in front of
said spur in the line of feed of the work, and a work-feeding mechanism.
2. In a sewing machine the combination with a needle-bar and its operating
mechanism, of two needle-carriers movably connected with said bar and pro-
vided with needles, mechanism for operating said carriers to move the said
needles from and towards each other, loop-taking devices co-operating with
said needles, a thread-dividing spur arranged beneath the work-plate of the
machine and adjacent to the paths of descent of said needles, means for operating
said spur to cause it to rise through the work before the descending needles
enter the latter, an awl or pricker arranged above the work-plate in front of
said spur in the line of feed of the work, and a work-feeding mechanism timed
to move the work forward once for each three vertical reciprocations of said
needle-bar.
3. In a sewing machine the combination with a needle-bar and its operating
mechanism, of two needle-carriers movably connected with said bar and pro-
vided with needles, mechanism for operating said carriers to move the said
needles from and towards each other, loop-taking devices co-operating with
said needles, a thread-dividing spur arranged beneath the work-plate of the
machine and adjacent to the paths of descent of said needles, means for operating
said spur to cause it to rise through the work before the descending needles
enter the latter, an awl or pricker arranged above the work-plate in front of
said spur in the line of feed of the work, and a work-feeding mechanism timed
to move the work forward once for each three vertical reciprocations of said
needle-bar, said operating mechanism for said needle-carriers being timed to
cause the needles to be separated at one descent of the needle-bar and to be
closed together at the next two descents thereof, the closed descents of the
needles occuring just before and just after the feeding movement.
4. In a sewing machine the combination with the driving shaft thereof and
a needle-bar operatively connected with said shaft, of two pivoted and con-

page_text: nected needle-carriers reciprocating vertically with said bar and one of which
carriers is provided with an operating arm, as 2, needles mounted in said car-
riers. a cam-disc, as H, geared to said shaft to rotate one to each three revolu-
tions of the latter, connections between said arm and cam whereby said arm is
vibrated to move the said needles towards and from each other, a thread-dividing
spur arranged beneath the throat-plate of the machine, mechanism for recipro-
cating said spur vertically, and a feeding mechanism for advancing the work.
5. In a sewing machine the combination with a needle-bar and its operating
mechanism, of two pivoted needle-carriers reciprocating vertically with said
bar and having a toothed connection with each other so as to be reversably
vibrated, one of said carriers being provided with an operating arm, needles
mounted in said carriers, means for vibrating said arm to move the said needles
from and towards each other, a thread-dividing spur located beneath the work-
plate or throat-plate and adjacent to the paths of descent of said needles, mech-
anism for reciprocating said spur vertically to cause it to rise through the goods
before the needles enter the latter, and a feeding mechanism for advancing the
work.
6. In a sewing machine, the combination with the driving shaft and the needle-
bar operatively connected therewith, of two pivoted needle-carriers having a
toothed connection with each other and one of which is provided with an operat-
ing arm, as, needles mounted in said carriers, and a cam geared to said shaft
and operatively connected with said arm so as to move the said needles towards
and from each other at intervals.
7. In a sewing machine, the combination with the driving shaft thereof and
a needle-bar operatively connected with said shaft, of a cam, as H, geared to
said shaft, two pivoted needle-carriers reciprocating vertically with said bar
and having a toothed connection with each other, one of said carriers being
provided with an operating arm as , a movable frame as I, to which said arm
is connected and which, in turn, is with said cam, to be operated thereby,
needles mounted in said carriers, loop-taking devices co-operating with said
needles, a work-feeding mechanism, a thread-dividing spur located beneath the
work-plate or throat-plate of the machine adjacent to the paths of descent of
said needles, and means for reciprocating said spur vertically to cause it to
rise through the work before the needles enter the latter.
8. In a sewing machine, the combination with two needles and means for
reciprocating the same vertically and for moving them towards and from each
other, and loop-taking devices co-operating with, said needles, of a thread-
dividing spur located beneath the work-plate or throat-plate of the machine
adjacent to the paths of descent of said needles, operating mechanism for recip-
rocating said spur vertically, a feeding mechanism for advancing the work,
and a vertically reciprocating awl or pricker above the work-plate located in
front of said spur and in the line of the feed, said awl or pricker being adjust-
able so that the distance of its working portion from the vertical path of move-
ment of said spur may be varied to correspond to different lengths of feed.
Dated this 22nd day of August
1899.
Dated this 2nd day of August
1899.
WALLACE FAIRWEATHER,
Of the Firm of Cruikshank & Fairweather,
Chartered Patent Agents,
62, Saint Vincent Street, Glasgow, Agent for the Applicant.