Improvements in Sewing Machines.
Year: 1889

page_text: Improvements in Sewing Machines.
I ELI WILLIAM BROADBENT of No. 261 Broadway, in the City and State of New
York, United States of America, Merchant's Clerk, 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:
One feature of my improvement consists in a hooked looper co-operating with a
needle, which looper is mounted on a rock shaft, and receives an oscillating or
reciprocating motion from the rock shaft; the rock shaft being longitudinally
movable. The rock shaft may be moved in one direction by a spring, and suitable
mechanism may be employed between the rock shaft and main shaft of the
machine, for imparting longitudinal movement to the rock shaft in the other
direction.
Another feature of my improvement consists in a guide below the needle plate
having a face approximately co-incident with the wall of the hole through which
the needle passes in the needle plate, but upon one side of said hole, in combination
with the hooked looper and rock shaft previously referred to. During the
movement of the rock shaft, the looper will be moved toward and from said
guide.
Another feature of my improvement resides in the feeder and, the means for
operating the same, which means comprise a main shaft, a second shaft, and
mechanism between the main shaft and second shaft for rotating the latter. Upon
the second named shaft is a crank. This crank engages a lever, on which is the
feeder. A spring moves the feeder in one direction and the crank in the other.
The second named shaft may be operated from the main shaft by an excentric on the
main shaft, an excentric rod connected with the looper shaft to operate the latter,
and a crank rod pivottally connected with the said excentric rod near one end, and
near its other end to a crank on the feeder shaft.
In the accompanying drawings,
Fig. 1 is a side elevation, parily in section, of a sewing machine embodying my
improvements.
Fig. 2 is an end elevation of the same, the parts being shown in the same relative
position.
Fig. 3 is a sectional view, in 'elevation, of the lower part of the mechanism as
shown in Fig. 1, certain of the parts being shown in a different position from that.
which they occupy in Fig. 1.
Fig. 4 is a detail view of a certain crank motion employed in the machine.
Fig. 5 is a detail view showing certain of the parts in a different position from
that which they occupy in Fig. 2.

page_text: Fig. 6 is a detail, partly in section, of a looper, and certain adjacent parts, the
same being shown in plan.
Similar letters of reference designate corresponding parts in all the Figures.
A designates the frame of the machine, and a a base piece therefor. The frame A
comprises an upright portion a¹, a lower arm a², an upper arm a³, and a head a*.
These parts may all be made integral with each other. Upon the arm a² is carried
a cloth plate a, provided with suitable apertures through which work the needle a
and a feeder E. This feeder is mounted upon, or forms a part of a lever G¹, which
lever is fulcrumed upon a pin or screw g, passing through a longitudinally extending
slot g of the lever, and engaging a portion of the frame.
The lever G' may
move freely along upon the screw g. J designates a shaft journalled in suitable
bearings on the frame A. Rotary motion is imparted to this shaft by means of a
'crank arm
J', which crank arm is pivottally connected near one end, to the upper
portion of an excentric rod D¹, deriving motion from an excentric D on a main
shaft a. The crank arm is connected near its other end to a crank J2 upon the
shaft J. When the excentric rod D¹ is moved up and down, longitudinal motion is
imparted to the crank arm J, of sufficient extent to cause the rotation of the crank J,
and consequently of the shaft J. A pin j, extending through a longitudinal slot 2 in
the rod J, guides the latter in its movement. Near the other end of the shaft J,
there is mounted thereon a crank J³, having a crank pin j³, which extends into an
opening in the lever G¹. The position and conformation of the opening in the
lever is such, that the rotation of the crank J³, causes not only an up and down
movement to be imparted to the feeder, but also a longitudinal movement to be
imparted thereto; in this instance, in a direction to feed the goods forward.
The crank pin 3 first contacts with the upper wall of the opening it, to raise the
feeder into feeding position, then, with the rear wall of said opening, to move the
feeder in a direction to feed the goods; then, with the lower wall of the opening, to
move the feeder downwardly, and thence again returns to its original position. The
return longitudinal movement of the feeder is effected by means of a spring J₁ con-
nected, near one end, to the lever G₁, and near its other end, to the frame of the
machine.
In order to regulate the length of stitch, or in other words, the range of longi-
tudinal movement of the feeder, have shown a stop I, having a cam surface i near
one end, arranged so, as to be brought to bear upon a, toe l, extending downwardly
from the lever G. By rotating the stop, the cam surface i may be caused to limit, to
a greater extent or less extent, the movement of the feeder in the direction in which
it is moved by the spring J. The stop may be locked in any desired position by a
set screw i².
B designates a presser foot mounted upon a presser bar b, which latter operates with
a yielding pressure, through the medium of a spring 61, in the usual manner. Thread
is supplied to the needle from a spool B₁, after passing through a tension device B² of
ordinary construction, and an eye b².
This machine is designed to sew a chain stitch, and in order to form a loop upon
the underside of the material being sewn, I provide a looper C. This looper has
imparted to it an oscillating motion about an axis, and also has a bodily longitudinal
movement in the direction of the length of the machine. It is provided with an
upwardly extending approximately straight, or bar like portion e, and, at its upper end,
with a hook c', extending at approximate, right angles to the direction of the length
of the portion c, and in the direction of oscillation of the looper. The hook portion c¹
is slightly off-set to one side, or toward the front end of the machine. The looper is
mounted upon a rock shaft D, which rock shaft is journalled, as shown at c and c³; in
the arm a of the frame. An oscillating or rocking motion is transmitted to the rock
shaft D by means of the excentric. rod D'. The excentric rod D' connects near its
lower end with a crank pin d, extending from a crank disc or segment. D³ rigidly
mounted upon the rock shaft D. When the main shaft a¹¹ is rotated, a rocking
motion is imparted to the rock shaft D, and consequently an oscillating or reciprocating
motion is imparted to the looper C.

page_text: The motion of the parts is so timed, that when the looper C has been moved to its
farthest extent in one direction, the needle has reached its lowest point, carrying
with it a loop of thread. At the moment of "dwell" of the needle, the return
movement of the looper C occurs, and the hook portion c¹ thercon enters the loop of
thread, and draws it forward. The needle then passes upwardly, and the forward feed
of the goods occurs. When the needle returns, on its down stroke, with another
loop of thread, it passes through the loop taken up by the looper, and the looper picks
up the loop just brought down by the needle, in the manner just described.
It is essential that the loop of thread brought down by the needle should be opened
out sufficiently to allow the looper to properly take up the loop, and also that the loop
should be opened out upon the proper side of the needle. It is further essential, that
the looper, after it has picked up the loop, should be brought into such a position,
that the needle, upon its next descent, will pass through the loop already picked up
by the looper. To accomplish the first of these, I provide a guide E extending
downwardly from the work plate a³, which guide has a vertical face, which is
coincident with the wall of the aperture through which the needle passes in its up and
down stroke, and which is toward the front end of the machine. When the needle
starts upon
its up-stroke, the guide E' maintains the thread close against the needle,
and prevents the opening out of the loop upon that side; all of the opening of the
loop, therefore, occurs upon the other side of the needle, or toward the rear, and is
therefore in a position to be readily taken up by the looper. It is to be borne in mind,
in this connection, that the looper travels upon one side of the needle only, that is,
upon the inner or rear side. The bodily longitudinal movement of the looper shaft
is for the purpose of bringing the loop thereon into a proper position' to be entered by
the descending needle.
The lengthwise movement of the rockshaft is accomplished in the following
manner :-
Upon the inner side of the crank disc or segment D³, is a cam surface d¹. Rigidly
mounted upon the frame A, is a cam d², having a cam surface d³, the cam surface of
which will be in the path of the crank disc or segment D³, when the latter is
reciprocated. The action of these two surfaces one against the other, causes the rock
shaft D to be moved longitudinally in one direction, the direction of such movement
being, in the example of my improvement shown, such as to move the looper C
away from the guide E. This movement occurs when the looper is being moved
into the position shown in Figs. 3, 5, and 6. In Fig. 3, it will be observed that the
cam surfaces d', d³, bave parallel portions in contact with each other. These parallel
portions are maintained thus in contact during that portion of the movement of the
fooper which occurs after the needle has taken the loop from the looper, and until
the looper has taken another loop off from the needle. When this last has occurred,
the longitudinal movement of the rock shaft D in the other direction occurs, the
parallel portions of the can surfaces d', d³, being no longer in contact. This move-
ment of the rock shaft is brought about by a coil spring F, surrounding the rock shaft,
and arranged in a suitable cavity f in the frame A. This coil spring abuts, near one
end, against the end wall of said cavity, and at the other, against a collar upon the
rock shaft. When the rock shaft D has been moved by the spring, the looper C will
be thrown into a position shown more clearly in Fig. 1, that is to say, the rear
portion of the hook will be brought into contact with the guide E'; the loop upon
the looper is therefore brought directly into the path of the descending needle, and
the latter passes readily through it. A "dwell" occurs at this point in the movement
of the looper, the same being occasioned by means of the slotted connection which
the excentric rod D' has with the crank pin d, as shewn more clearly in Fig. 1, and.
which admits of a considerable lengthwise movement of the excentric rod, without
imparting rotary motion to the shaft.
I have shown the lower portion of the excentric rod as provided with a longi-
tudinally extending cavity e, in which is arranged a coil spring e', acting upon a
pin e², which bears upon the crank pin d. This arrangement tends to hold the crank
disc or segment in close contact with a stop pin upon the cam d², while the

page_text: independent motion of the excentric rod occurs. The stop operates to prevent the
rotation of the crank disc or segment D³ too far in one direction.
29
It will be observed that the looper, having but a very short range of movement,.
forms but a very small loop, only sufficient, in fact, to enable the needle to pass through
it. Owing to this, no
"take up
is necessary on the machine, the movement of the
needle being sufficient of itself to form a tight stitch. The small size of the loop also
admits of the use of either coarse or fine thread, without any alteration of the
tension.
It is apparent that as the loop of thread does not have to pass over the looper, a
number of loopers may be arranged on the same rock shaft, and co-operate with a
number of needles.
Having now particularly described and ascertained the nature of the said Inven-
tion 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 reciprocating needle, of a rock
shaft, a hooked looper mounted thereon, and receiving an oscillating or reciprocating
motion from, the rock shaft, said rock shaft being longitudinally movable, and mechanism
for imparting motion to the rock shaft, substantially as specified.
2. In a sewing machine, the combination, with a reciprocating needle, of a main
shaft, a rock shaft, a hooked looper upon the rock shaft, deriving an oscillating or
reciprocating motion therefrom, a spring for imparting longitudinal movement to the
rock shaft in one direction, and mechanisin between the main shaft and the rock shaft
for imparting longitudinal movement to the latter in the other direction, substantially
as specified.
3. In a sewing machine, the combination with a reciprocating needle, of a plate
provided with an aperturo through which the needle will pass, a guide below said
plate, and having a face approximately coincident with the wall of said aperture upon
one side of the latter, a rock shaft, a hooked looper mounted upon said rock shaft,
and mechanism for imparting. .il longitudinal movement to said rock shaft, whereby
the looper will be moved toward and from said guide, substantially as and for the
purpose specified.
4. In a sewing machine, the combination with a shaft, of a crank on said shaft, a
lever provided with an aperture with which said crank engages, a feeder on said lever,
a main shaft, mechanism between the main shaft and the shaft first named, for
causing the rotation of the said crank, in order to move the feeder in one
direction, and a spring for moving the feeder in the other direction, substantially as
specified.
5. In a sewing machine, the combination, with a shaft, of a crank on said shaft, a
lever provided with an aperture with which said crank engages, a feeder on said lever,
another crank on the shaft, a main shaft, an excentric thereon, an excentric_rod, a
looper shaft operated from said excentric rod, a crank rod pivotally connected to said
excentric rod near one end, and a crank on the said shaft first named, with which said
rod is also connected, substantially as specified.
6. In a sewing machine, the combination, with a feeder, of a shaft, a crank on the
shaft for operating the feeder, a rock shaft, a looper on the rock shaft, a main shaft, an
excentric on the main shaft, an excentric rod operated by said excentric to rock the
rock shaft, and a crank rod operated from the excentric rod, to rotate the shaft first
named, substantially as specified.
Dated this 12th day of February 1889