Improvements in Sewing Machines.
Year: 1899

page_text: Date of Application, 23rd Aug., 1899-Accepted, 14th Oct., 1899
[Communicated from abroad by THE SINGER MANUFACTURING COMPANY, of New
York, United States of America, Sewing Machine Manufacturers.]
Improvements in 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 sewing machines and more particularly to hem-
stitch or openwork sewing machines of that class in which vertically reciprocating
piercers to divide or separate the threads of the woven fabric are employed in
connection with a vertically and laterally moving needle-bar and needle and
irregular feed; the invention having for its object to provide a machine of this
class which is simple in construction and positive and silent in operation, so
that it is capable of being run at high speed; as also to provide a machine in
which the piercer-bar is operated independently of the needle-bar so that the
piercer or piercers may descend in advance of the needle and may remain in
the work after the needle has risen, so as to avoid any danger of catching the
needle-thread on the point of the piercer adjacent to the needle.
In this improved machine, the upward, forward and backward movements of
the feed-bar are all positive and are preferably imparted to said feed bar from a
single rotating cam-wheel which also preferably imparts lateral movements to
the needle-bar and needle, while the needle and piercer bars are reciprocated
vertically, but independently of each other, from a single rotating crank-pin at
the forward end of a driving shaft journalled in the upper part of the bracket-
arm of the machine.
In the accompanying drawings Fig. 1 is a side view, partly in' vertical section,
of the improved machine, and Fig. 2 is a bottom view thereof. Fig. 3 is a
top view of the same, partly in horizontal section, and Fig. 4 is a' front end view
with the face-plate removed and with the presser-foot omitted for clearness of
illustration. Fig. 5 is a detail view of part of the operating mechanism of the
needle and piercer-bars. Fig. 6 is a detail perspective view of the double
crank from which the needle-bar and piercer-bars are operated, and Fig. 7 a'
detail view of part of the feed mechanism.
In the drawings A denotes the bracket-arm and B the work-plate of one style
of Singer oscillating shuttle sewing machine embodying the present improve-
ments. C is the driving shaft journalled in the upper part of the arm A and
provided at its forward end with a crank-disc c having a crank-pin c¹ which is
encircled by an eye formed at the upper end of a pitman d, the lower end of
which is connected to the needle-bar D so as to impart regular vertical move-
ments thereto in a well-known manner. The driving shaft C is provided with
a bevel-pinion e meshing with a bevel-gear el attached to or formed integral
with a cam-wheel E having a peripheral cam-groove 2 entered by a stud f
depending from the rear arm of an elbow lever F having a vertical fulcrum-

page_text: stud fitted in a suitable bearing in the bracket-arm A; the forward or trans-
verse arm of said lever having a groove fin which is adjustably secured, by
a set-screw f³, the rear end of a pitman f jointed at its forward end, at f³, to
the top of a swinging frame or gate d in which the needle-bar D has its bearings
and in which said needle-bar reciprocates vertically. The swinging needle-bar
frame or gate is pivoted on centre-screws 2 in the usual manner.
The crank-pin c¹ of the disc c is provided with an off-set ca extending inwardly
toward the shaft C and on which is formed a second crank-pin engaging a
cam-slot in a lever g pivoted at gl and provided with a stud 92 encircled by an
eye on the upper end of a pitman ³ jointed at its lower end to a block or
collar attached to the piercer-bar G. The connected crank-pins cl and c³
form a double crank, the primary crank-pin c¹ being directly connected to the
needle-bar, to impart a regular motion thereto, and being indirectly connected
to the piercer bar so that the latter may have irregular or differential movements,
owing to the fact that it is operated independently, (or measurably so, at least)
of the needle-bar.
The term "regular" as herein employed with reference to the reciprocating
movement of the needle-bar is intended to describe such a movement as the
needle-bar will receive by reason of a direct pitman connection with a regularly
rotating crank; or, in other words, a movement which is uniformly accelerated
from the time the needle-bar commences to descend or rise until it reaches its
maximum speed, and is then uniformly retarded to the end of its stroke. The
term "irregular or differential " as herein used and describing the movements
of the piercer-bar is intended to refer to reciprocating movements which are
not uniformly accelerated or retarded as are the movements of the needle-
bar, these irregular or differential movements of the piercer-bar permitting the
latter to descend in advance of the needle-bar and to rise with or after the
needle bar has risen.
The said piercer-bar is preferably provided at its lower end with an off-set
bracket or stock g³ to which one or more piercers 96 are secured by a suitable
set screw or screws. The piercer with which the needle d³ is, at times, in juxta-
position, is grooved on its side towards the needle, as is common with hem-stitch
machine piercers, so that the needle in descending into the holes in the fabric
formed by the piercer will be partly housed within the same so as to further
push aside or divide the threads of the fabric already displaced by the piercer.
When two or more piercers are employed they are arranged one behind the other
in the direction of the feed of the work and are spaced to coincide with the
length of feed. The above-described indirect or independent connection of the
piercer-bar with the needle-bar operating crank-pin admits of such a timing
of the piercer-bar, relative to the regularly-operated needle-bar, as will permit
the piercer-bar to be moved downward before the needle-bar, to cause the piercers
to pierce the work to divide the threads thereof, before the needle descends, and
so that the piercers may remain in the work, if desired, after the needle rises.
The cam-wheel E is provided in its front face with a cam-groove e entered
by a stud h carried by the upper arm of an elbow lever H the lower or horizontal
arm of which is preferably grooved for the adjustable connection thereto of the
upper end of a link h¹ connected at its lower end to an arm of the feed-
operating rock-shaft I having, near its forward end, arms between which the
feed-bar Jis pivotally mounted so as to be moved positively forward and back-
ward by virtue of the connections, just described, with the cam-groove e³.
The cam-wheel E has in its rear face a cam-groove e entered by a roller-
stud on the upper arm of a three-armed lever or rocker K pivoted
at to a part of the arm A, and to the lower arm of said lever K is
attached the upper end of a connecting rod m jointed at its lower end to an
arm n near the rear end of a feed-lifting rock-shaft N having near its forward
end an arm n¹ provided with a roller-stud on which the feed-bar J rests; a

page_text: spring n being, in the present instance, employed to press the said feed-bar
down against said roller-stud.
The shuttle operating mechanism preferably employed in the machine herein
shown and described is that of the well-known Singer "overseaming" machine
and comprises an oscillating shuttle (not shown) working in the shuttle-race O
and operated from a crank p on the driving shaft C through a pitman p and
rocker pa suitably connected to a short, transversely arranged, shuttle-operating
rock-shaft at the forward end of the machine; but as this shuttle mechanism
forms no part of the present invention it need not be further described.
The machine constructed as herein shown is organized from three-stitch pattern
hem-stitching, and in the formation of which three-stitch pattern the needle
descends twice in the body of the goods and once in the hem, with the feed so
timed that the goods will be fed backward between the first and second needle
punctures in the body of the goods, but will be fed forward between the second
needle puncture in the body of the goods and the puncture in the hem as also
between the puncture in the hem and the first puncture in the body of the goods.
This result is effected in the present instance by the particular forms of the
feeding cams and of the cams for moving the needle-bar laterally herein em-
ployed, and it will therefore be understood that the forms as also the timing
of these cams may be varied so as to produce any of the well-known hem-stitch
patterns which may be desired. Thus in the present instance the cam-wheel E
is geared to the driving shaft C so as to perform one revolution to each three rota-
tions of said shaft, while the needle-bar cam-groove e² of said wheel is constructed to
impart but one back and forth lateral movement to the swinging needle-bar
frame or gate at each rotation of said cam-wheel; the needle-bar being retained
in one of its lateral positions during about two thirds of the tinie occupied by
the rotation of said cam-wheel. Also the feeding and feed-lifting cam grooves e³
and e, respectively, of the said cam wheel are, in the present instance, so con-
structed and relatively timed that the feed bar will be moved back and forth
horizontally twice during each rotation of the said cam-wheel, while the said
bar will be raised and lowered but once during each rotation of said cam-wheel;
one of the backward movements of the feed-bar occurring while the said feed-bar
remains lifted so as to produce the backward feed heretofore referred to. We
do not therefore wish to be understood as limiting our invention to the particular
constructions and relative timing of the cams or other parts herein shown and
described, as the details of the invention may be varied widely, within the pro-
vince of mechanical skill, without departing from the essence 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 hem-stitch sewing machine, the combination with a suitable feeding
mechanism, of a needle-bar, means for moving said bar laterally, a rotating
crank-pin connected to said needle-bar to impart vertical movements thereto,
a piercer-bar, a pitman connected to said piercer-bar and an intermediate con-
nection between said crank-pin and pitman whereby irregular or differential
movements may be imparted to said piercer-bar from said crank-pin.
2. In a hem-stitch sewing machine, the combination with a suitable feeding
mechanism, of a rotating crank-pin, a needle-bar and means for moving the
same laterally, a pitman connecting said needle-bar with said crank-pin, a piercer-
bar, a vibrating operating device actuated by said crank-pin, and a pitman con-
necting said vibrating operating device with said piercer-bar; whereby the said
needle-bar is adapted to have regular vertical movements and the piercer-bar
irregular vertical movements, substantially as set forth.
3. In a hem-stitch sewing machine, the combination with a suitable feeding
mechanism, of a rotating double crank, a needle-bar operatively connected to
one part of said crank so as to have regular movements, a piercer-bar, and a

page_text: lever and pitman connecting said piercer-bar to the other part of said crank
so that said piercer-bar will be differentially operated.
4. In a hem-stitch sewing machine, the combination with a driving shaft
arranged about the work-plate, of a needle-bar operatively connected to said
driving shaft to be reciprocated vertically, a feed-bar arranged below the work-
plate, a swinging frame or gate in which said needle-bar is mounted, a single
rotating cam wheel or device above the work-plate and geared to said driving
shaft and provided with a needle-gate, cam and two feed cams, and connections
between said cams and said frame or gate and said feed bar, whereby said frame
or gate is moved laterally and the said feed bar is moved both horizontally and
vertically at proper intervals.
5. In a hem-stitch sewing machine, the combination with a needle-bar mounted
to move laterally and means for reciprocating said bar vertically, of a feed-bar
arranged below the work-plate and a common rotating device above the work-
plate connected to said feed-bar to operate the same both vertically and
horizontally and also connected to said needle-bar to impart lateral movements
thereto.
6. In a hem-stitch sewing machine, the combination with a driving shaft,
of a laterally movable needle-bar connected with said shaft to be reciprocated
vertically, a feed-bar below the work-plate, and a rotating, feed-operating device
above the work-plate geared to said driving shaft and connected with said feed-
bar to operate the same both vertically and horizontally, and also connected to
said needle-bar to impart lateral movements thereto.
7. In a sewing machine, the combination with the stitch-forming devices thereof,
and with a driving shaft to operate the same, of a feed-bar below the work-plate,
two rock-shafts also below the work-plate and connected with said feed-bar to
move the said feed-bar vertically and horizontally, and a rotating cam-wheel
above the work-plate geared to said driving shaft and provided with two cam-
grooves, and connections between the said cam-grooves and rock-shafts.
8. In a sewing machine, the combination with a stitch-forming mechanism
comprising a vertically and laterally reciprocating needle-bar and a driving
shaft from which said bar is operated, of a feed-bar two rock-shafts connected
with said feed-bar to move the latter both horizontally and vertically, and a
rotating cam-wheel geared to said driving shaft and provided with three cam-
grooves, and connections between said cam grooves and said rock-shafts and
needle-bar whereby said bar will be moved laterally at intervals and whereby
also the said shafts will be rocked to impart proper movements to said feed-bar.
9. In a sewing machine, the combination with the stitch-forming devices thereof
and a driving shaft for operating the same, of a feed-bar, means for moving
the same vertically, a rock-shaft connected to said feed-bar to move the same
horizontally, a cam geared to said driving shaft and an elbow-lever above the
machine work-plate and one arm of which is arranged to engage said cam and
the other arm of which is connected to said rock-shaft.
10. In a sewing machine, the combination with a driving shaft, of a hori-
zontally swinging needle-bar frame, a needle-bar mounted therein and connected
with said shaft to be reciprocated vertically, a feed-bar, two rock-shafts for
operating said feed-bar, a cam-wheel geared to said driving shaft and provided
with three cam-grooves, an elbow-lever operated from one of said cam-grooves
and connected with said needle-bar frame to swing the said frame horizontally,
a second elbow-lever operated from another of said cam-grooves and connected
with one of said feed-operating rock-shafts, and a three-armed lever or rocker
operated from the third one of said cam-grooves and connected with the other of
said rock-shafts.
11. In a hem-stitch sewing machine, the combination with a feeding mechanism,
of a stitch-forming mechanism comprising a horizontally swinging frame or
gate and a needle-bar mounted therein, of a rotating double crank-pin one part
of which is connected with said needle-bar to reciprocate the same vertically,

page_text: a piercer-bar, a lever provided with a slot entered by the other part of said crank-
pin and which lever is connected with said piercer-bar to reciprocate the same
vertically but in different time from said needle-bar.
Dated this 22nd day of August 1899.
WALLACE FAIRWEATHER,
Of the Firm of Cruikshank & Fairweather,
Chartered Patent Agents, 62, Saint Vincent Street, Glasgow,
Agent for the Applicant.