Improvements in Sewing Machines.
Year: 1892

page_text: Date of Application, 9th Aug., 1892-Accented, 17th Sept., 1892
COMPLETE SPECIFICATION.
[Communicated from abroad by THE SINGER MANUFACTURING COMPANY,
of New York, in the United States of America, Sewing Machine Manu-
facturers.]
Improvements in Sewing Machines.
I, ALEXANDER ANDERSON Manager of The Singer Manufacturing Company's
Works, Kilbowie, Dumbartonshire do hereby declare the nature of this invention
and in what manner the same is to be performed (as communicated to me) to be
particularly described and ascertained in and by the following statement :-
This invention which relates to sewing machines consists (1) of improvements
in the mechanism for operating the needle bar and (2) of an improved folding or
plaiting attachment for such machines, the improvements being applicable in con-
junction in the same machine or separately.
The first part of my invention relating to mechanism for operating the needle-
bars of sewing-machines, has for its objects the provision of simple means for
causing the needle-bar to travel faster during the lower half of its stroke than
during its upper half, whereby ample time is permitted in which to operate the
feed and take-up mechanisms, and also whereby thick fabrics may be sewed with
a short-stroke needle-bar as hereinafter more fully appears.
Other minor objects will appear in the course of this description.
In Sheet 1 of the accompanying drawings which illustrates the first part of my
invention
Figures 1 and 2 represent vertical sectional views of a portion of a sewing
machine showing the parts of my improvement in different positions; Figure 3 is
a detail sectional view showing the parts connecting the crank shaft to the needle-
bar and Figure 4 a sectional view showing the cam on the end of the driving
shaft.
Referring to the drawings by letters, a designates the driving shaft of a sewing
machine, which is journalled in the usual manner in the stationary arm 6 of the
machine. On the end of the shaft is rigidly secured a cam a' provided with a
straight groove all across its face, said cam rotating within a cavity & formed on
the end of the arm b. To an angular flange or depending portion 6 formed on the
end of the arm b, is secured, by means of screws c³, the face plate or head c,
which is made hollow to receive and enclose the parts that operate the needle
bar. The advantage of providing a face-plate or casing constructed as described,
and journalling the needle-operating mechanism therein, and removably securing
it to the outer end of the machine-arm, is that said casing and operating-mechanism
contained therein, may be removed when desired from the arm of the machine, for
cleaning or other purposes, without affecting the relation or adjustment of the
parts contained therein. It also facilitates the assembling of the parts when the
machine is first put together. Journalled in bearings in the side of the casing c,
near its upper end, is a horizontal shaft d whose axis is substantially parallel with,
but eccentric to, the axis of the main driving shaft, being journalled a little above
the centre of the latter. This shaft is bent into a crank-arm between its ends
and its ends are journalled in bearings d³, d³ formed in the casing c on both sides
of the said crank arm. This arm d' works within the casing c and is connected to
a vertical pitman e pivotally connected at its lower end to the upper end of a block
or cross head e sliding within the casing. This sliding cross-head may be of any
desired form but must fit closely within the hollow casing, the cavity of the casing
being the same shape as the cross-head in horizontal section, in order to provide a
bearing surface entirely encircling and bearing on the vertical sides of said cross-

page_text: head for a purpose that will hereinafter appear. The needle bar ell is secured within
a central socket, formed in this cross-head, by means of suitable set-screws tapped
in the cross-head, the needle-bar passing through the lower end of the casing
and being provided with the usual needle-holding devices.
The inner end of the crank shaft is journalled, for convenience of insertion and
removal, between a pair of removable rectangular bearing blocks d", said blocks
being fitted in the inner side of the casing c. The inner end of the crank-shaft is
provided with a radial arm which revolves within the cavity b¹ formed in the end
of the sewing machine arm and is provided with a wrist pin fat its end, said
wrist pin carrying a rectangular block f" which works in the face of the cam.
In operation, it will be observed, the rotation of the main-shaft through the
medium of the cam and crank shaft imparts the reciprocating movement to the
needle-bar, the block on the end of the radial arm sliding back and forth in
the groove in the cam, as is evident.
The essential features of this part of the invention consists in journalling the
needle-bar crank shaft eccentrically to the driving shaft whereby the needle bar
shall have an irregular movement imparted to it, moving quickly while passing
through the fabric and slowly during the upper part of its stroke.
It will be observed that when the crank-shaft is in the position shown in Fig. 1,
the needle-bar is at its lowest point of movement and the radial arm on the crank-
shaft and its sliding block are at their highest points, that is at the greatest distance
from the centre of the driving shaft, and when the crank shaft is in the position
shown in Fig. 2 the needle-bar is at its highest point and the sliding block is at its
lowest point and nearest to the axis of the driving-shaft. In this way the leverage
of the cam is augmented when the sliding-block is in the vicinity of its highest
point and decreased when in the vicinity of its lowest point, or limit, the result of
this necessarily being to move the needle-bar faster during the lower part of its
stroke than during the upper portion thereof. This moving the needle-bar slower
while the needle is above the fabric not only allows ample time in which to operate
the feed and take-up mechanisms without in the least reducing the speed of the
machine, but it also permits the use of a short stroke needle-bar in sewing through
thick fabrics, as is evident. This arrangement also permits the needle-bar to be
shortened, whereby its weight and liability to vibration, during operation, are
materially reduced.
It will also be observed that the crank-shaft has a bearing at each end and that
the pitman is connected to it between its two bearings, whereby greater durability
and better control of the needle-bar are obtained than could be secured by attaching
the pitman to the side of the needle-bar in the old way.
The pitman and needle-bar are connected to the cross-head in such a manner
that they are in the same vertical plane in all parts of the stroke, and when in the
the position shown in Fig. 3, are in direct vertical line with each other, whereby
the side thrust, due to the old manner of connecting the parts, is avoided.
The advantage of locating the cross-head e' within the casing c, and having it
bear on the vertical sides of the cavity of said casing, are obvious. The pitman e,
having a lateral as well as a reciprocating motion, would cause, if secured directly
to the needle-bar, a vibration or twisting of said bar, but being pivotally secured
to the upper end of the cross-head e', and this cross-head fitting within the cavity
of the casing and having the needle-bar secured to its lower end, the cross-head
will receive the thrust of the pitman, and the needle-bar will be moved up and
down with a perfectly steady motion. It also facilitates the construction, inasmuch
as a shorter and consequently much more rigid needle-bar may be used.
I do not confine myself to the exact construction of parts herein shown, as the
same may be readily varied without departing from the spirit of the invention in
the least.
The second part of my invention which relates to that class of sewing machin
attachments adapted to form folds or plaits in fabrics and to guide the same to the
stitch-forming mechanisms of sewing machines, has for its object to provide a

page_text: simple and convenient attachment, of the class referred to, whereby two reversely-
laid folds or plaits may be simultaneously produced in a piece of goods and may be
held and guided to a two-needle sewing machine which will thus simultaneously
stitch both folds or plaits.
In carrying this part of my invention into effect I provide, in connection with a
stationary guide or folder arranged centrally in front of the needles of the machine,
and having a top plate or part forming two overhanging guiding portions or edges,
two swinging plait-forming blades or knives arranged to enter beneath the over-
hanging portions or edges of the stationary guide and thus, in connection therewith,
to form two reversely laid plaits or folds which are properly held and guided to the
needles of the sewing machine. The swinging plaiting blades or knives are carried
by pivoted arms which are preferably so connected together that the movement of
one into or out of working position will cause a similar movement of the other.
In Sheet 2 of the accompanying drawings, which illustrate this part of my
invention,
Fig. 1 shows, in front side elevation, a portion of a sewing machine, with my
improvements applied thereto, the parts being in working positions.
Fig. 2 is a similar view but with the plaiting blades swung outward for the
insertion of the work.
Fig. 3 illustrates my device as seen from the front end of the sewing machine
head.
Fig. 4 is a plan view of the folding guide and plaiting blades with the latter in
the positions shown in Fig. 1.
Fig. 5 is a top view of the stop which holds the plaiting blades out of working
position, one of the plaiting-blade carrying-arms being shown in cross section.
Fig. 6 is a plan view of a modified form of my invention, with the parts in
working position and
Fig. 7 is a similar view with the plaiting blades swung aside for the insertion of
the work.
Fig. 8 illustrates this form of my invention as seen from the front end of the head
of the machine, and
Fig. 9 is a view looking from the front side of the sewing machine, of the plaiting
olades in the positions shown in Fig. 6.
Fig. 10 illustrates the work to be made by my device.
A denotes a portion of the arm of a sewing machine and B a part of the work-
plate thereof. Referring now more particularly to the preferred form of my
nvention shown in Figures 1 to 5 in Sheet 2 of the drawings, a denotes a plate or
mall bracket secured to the lower part of the depending portion or head A³ of the
rm A. and to the said plate or bracket are pivoted at their upper ends two arms or
evers C carrying at their lower ends the swinging plaiting blades c.
The arms C
re preferably connected together by intermeshing teeth d, formed thereon adjacent
o their pivots, and by a spring e, which has a tendency to force them together.
To limit the inward movements of the arms C under the stress of the spring e, so
s to hold the plaiting blades in proper working position, I preferably provide a
top device consisting, as herein shown, of a bar or projection interposed between
he said arms C and engaged by projections thereon consisting preferably of
djustable screws g arranged to abut against said bar or projection f
To hold the plaiting blades out of working position as shown in Fig. 2 when the
work is to be inserted, I provide a retaining arm H suspended from the plate a and
aving a shoulder at h which engages one of the arms C as shown in Figs. 2 and 5
nd thus holds said arm outward until it is released from said shoulder which is
one either by pressing the arm H inward (said arm being preferably a spring arm
r being spring-supported as by the spring hanger ³) or by springing the arm C
utward away from the retaining arm. When the arm C is swung outward it rides
p a slight incline at h¹ on the arm H until it comes opposite the shoulder / when
springs into engagement with said shoulder.
The needle bar I carries two needles i and the presser foot J is provided with

page_text: two holes for the passage of said needles, and arranged centrally in front of said
needles is the stationary guide K which co-operates with the plaiting blades c.
The said guide K is preferably attached to the work-plate B and, as herein shown,
said guide consists of a small block having vertical guiding faces on its opposite
sides, said block being surmounted by a plate & which overhangs the same on both
sides to form projections beneath which the plaiting blades extend in making the
reversely laid folds or plaits. The width of the plate k will determine the distance
between the plaits or folds m (Fig. 10) being made, and for varying the work
interchangeable plates of different widths will be provided. The plaiting blades,
as also the plate or top plate or portion of the guide K, are preferably formed with
rounded or bluntly pointed forward ends to assist in the formation of the folds or
plaits in the work as the latter is guided forward to the needles.
In the form of my invention shown in Figs. 6, 7, 8 and 9 of the drawings the
plaiting blades care carried by horizontal arms C₁ secured by vertical pivot
screws to a bracket a' attached to the head A' and which is shown as being
provided with a steadying portion or sleeve a² surrounding the presser bar J¹. The
arms C are shown as being provided with intermeshing teeth d', as in the preferred
form of my invention, and are connected by a coil spring e¹ which draws them
together until their inward movements are limited by stops arranged in front
of their pivots. When the said arms C¹ are thrown outward a little further
than shown in Fig. 7 the spring e will be slightly rearward of the centres of
the pivots of said arms and will then hold said arms separated, the outward
movements of said arms being limited by the stops f' rearward of the arms
which stops will then be in contact with each other.
In the use of try attachment the plaiting blades are swung outward, as shown
in Figs. 2 and 7, and a piece of fabric to have the reversely laid plaits formed
therein is then laid upon the stationary guide K and the plaiting blades are swung
inward thus forcing portions of the fabric beneath the overhanging edges of said
guide and forming two reversely laid plaits or folds. The work is then drawn
forward beneath the needles, and the presser foot being lowered the machine is
started when the work will be drawn forward by the feed of the machine and
the reversely laid plaits or folds of any desired length will be formed and
stitched, as will be understood. My device is particularly adapted for use in
forming the central plaits of shirt bosoms but may be employed for any other
kinds of work in which it is desired to simultaneously fold and stitch two
reversely arranged plaits.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be perforined, (as communicated to me), I
declare that what I claim is;
1. The combination of an arm of a sewing machine provided with a cavity, a
shaft journaled therein and carrying a cam at its end, said cam working in said
cavity, a frame or casing c secured on the end of the arm, removable journal
blocks d secured in an opening in the casing c adjacent to the cavity, a crank-
shaft journaled between said journal-blocks and carrying an arm engaging the cam,
and means connecting the needle-bar to the crank-shaft, substantially as described
with reference to Sheet 1 of the drawings annexed.
2. The combination of an arm b, a hollow frame or casing c secured on the end
of the arm, a crank-shaft removably enclosed in the upper end of the casing and
having its ends journaled in opposite sides thereof, means for operating this crank-
shaft, a cross-head e' sliding in the hollow-casing, a pitman e connecting the cross-
head to the crank-arm between its ends, and a removable needle-bar secured to said
cross-head in line with the pitman, substantially as described with reference to
Sheet 1 of the drawings.
3. In a sewing machine, the combination of the arm thereof, a driving-shaft
mounted in said arm, a hollow frame or casing c on the arm, a cross-head sliding in
said hollow-casing, the walls of the cavity entirely surrounding the cross-head and

page_text: bearing on all its vertical sides, means for connecting the cross-head to the driving-
shaft to cause said cross-head to have a reciprocating motion, a needle-bar connected
to the lower end of the cross-head and projecting through the casing and carrying
needle-holding devices at its lower end, substantially as described with reference to
Sheet of the drawings annexed.
4. In a plaiting attachment for sewing machines, the combination with a central
guide having overhanging edges, of two swinging plaiting blades, and pivoted arms
by which said blades are carried.
5. In a plaiting attachment for sewing machines, the combination with a central
guide having overhanging edges, of two swinging plaiting blades, and two connected
pivoted arms by which said blades are carried, said arms having intermeshing
portions so that a movement of one will cause a simultaneous movement of the
other.
6. In a plaiting attachment for sewing machines, the combination with a central
guide having overhanging edges, of two swinging plaiting blades, two pivoted arms
by which said blades are carried, a spring for forcing said arms towards each other,
and a suitable stop-device for limiting their inward movements.
7. In a plaiting attachment for sewing machines, the combination with a central
guide having overhanging edges, of two swinging plaiting blades arranged to enter
beneath said overhanging edges, two pivoted arms by which said blades are carried,
a spring for forcing said arms towards each other and adjustable stops for limiting
their inward movements and for determining the positions of the plaiting blades
relative to the overhanging edges of the said guides.
8. In a plaiting attachment for sewing machines, the combination with a central
guide having overhanging edges, of two connected swinging arms carrying plaiting
blades arranged to enter beneath said overhanging edges, and a retaining device to
hold the plaiting blades separated from each other.
9. The combination with the central guide K having overhanging edges, of the
pivoted arms C carrying the plaiting blades c arranged to enter beneath said edges,
said arms having the intermeshing teeth d and the stop-screws or projections g, the
stop-bar or projection interposed between said arms, and the spring e serving to
force said arms towards each other.
Dated this 8th day of August 1892.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.