IMPROVEMENTS IN SEWING MACHINES
Year: 1878

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for the Invention of
"IMPROVEMENTS IN SEWING MACHINES." A communication from abroad by
Job A. Davis, of Boston, Massachusetts, United States of America.
Sealed the 18th June 1878, and dated the 12th April 1878.
COMPLETE SPECIFICATION filed by the said William Robert Lake at the
Office of the Commissioners of Patents on the 12th April 1878.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "IMPROVEMENTS IN SEWING MACHINES." A
communication from abroad by Job A. Davis, of Boston, Massachusetts, United
States of America.
This Invention relates to a sewing machine wherein is employed a curved or
circular shuttle, having a rotary reciprocating motion in a circular race, and in
connection therewith to form the stitch is employed an eye-pointed needle, deriving
its motion from a crank.
The arm for imparting motion to the shuttle driver is also operated from a crank,
and the said machine may be driven rapidly and with less power than would be
the case if these motions were derived from cams.
In the accompanying Drawings,-
Figure 1 is a side elevation of this improved machine; Figure 2 is a plan or top
view; Figure 3 is an inverted plan; and Figure 4 is a front elevation of the
same.
Figure 5 is a longitudinal section on the line x, x, of Figure 3, representing
mechanism for driving the shuttle and feed, the shuttle being removed.
Figures 6, 7, 8, 9, and 10 are views of the shuttle and bobbin.
Figures 11 and 12 are plans with the work plate removed, showing the shuttle
and bobbin in different positions; Figure 13 is an inverted plan of the said work
plate.

page_text: A is the table or frame of the said machine; B is the standard ending in the
head C. It is secured to the table by a horizontal arm B' underneath the table,
which is bolted to the table at a and keyed at b.
D is the driving shaft supported in bearings l, l. It is driven by a combined
pulley and balance wheel E, by means of a crank F, which carries a connecting
rod G to vibrate the rocking lever H, pivotted to the standard at h to operate the
needle bar I through a link g in the ordinary manner. The needle i is secured to
the needle bar by a clamp, as shown.
J is the presser foot bar; j, the presser foot; K, the lifter attached to the presser
foot bar; and k, a spring attached to the standard and tending to force the presser
foot down upon the work, the force of the pressure being regulated by the adjusting
screw C.
Lis the take-up pivotted to the head, and operated downwards by a shoulder
formed by cutting out a portion of the needle bar, as shown at d, and lifted by a
roller e on the stud which connects the link g with the needle bar. A friction
spring keeps the take-up from falling by its own gravity.
S is the shuttle vibrating in a circular race bored in the table under the work
plate. The race is so bored out at the top as to afford an opening for the shuttle,
a circular ledge m being left on which one edge of the shuttle bears, and as the
shuttle moves this ledge acts to support the shuttle on the side opposite the part
supported and acted upon by the shuttle carrier.
The shuttle carrier T is a disc on the end of a vertical vibrating shaft n, the said
dise having an upward projection o curved to coincide with the periphery of the
disc, and formed to embrace the shuttle and work between its point and heel.
The shaft n has a pinion p and a set scrow q, as shown, and is vibrated by a
rack w, having a reciprocating motion in horizontal ways in a projection y under
the frame, the said reciprocating motion being imparted to the rack by a crank &
on the driving shaft and a link z¹. The crank s is attached to the driving shaft
by an adjustable hub 2 and by set screws.
When the crank z and the link ¹ are in line with each other and parallel with
the rack, which occurs at each extreme position of the rack, and when they are
approximately in these positions there is no practical movement of the shuttle
carrier and the shuttle is at rest.
V is the feed bar, having a projection with a roughened face working through a
slot in the table. The said feed bar is held in position against a collar s¹ on the
end of the shaft q', shown in dotted lines, and a projection p³ from the frame by an
adjustable clamp o¹. The feed bar is cut with a downward projection ¹, as shown,
to bear against an excentric pin n¹ on the collar s¹, the said collar being secured by
a set screw to the shaft q', which shaft has bearings in the projection y. A wedge
plate secured to the feed bar by a set screw, as shown, also lies against the pin n¹, 4
affording a means of adjusting the upward motion of the feed. The shaft q¹is
turned by a slotted crank m² rigidly connected with it, and also with the wrist pin
of the crank z, this wrist pin works in the said slot.
Y is a wire spring secured to the frame at projections A, k', and acting against
the rear end of the feed bar in two directions to throw the rough projection down- 4
ward and backward, while the excentric pin n' acts in two directions to carry the
roughened projection upward and forward.
The length of the feed movement is regulated by a steel lever Z, pivoted at j¹,
and acting against a shoulder i' on the feed bar to limit the distance, to which the
spring Y throws the feed bar backward.
The shuttle S may be considered as divided into two parts, namely, a case for
the bobbin and a hook ending in the shuttle point r, as shown. The said shuttle
has the peculiar shape shown in the Drawings; Figure 6 shews the bottom side,
and Figure 9 shews the top side of the same. From the point r on the bottom
side to the heels on the top side it is circular, from the heel to the point it is cut 5
away, as shown,
The part of the shuttle forming the bobbin case is cored out for the bobbin t,

page_text: which runs on a stud projecting from the back of the shuttle at the centre of the
bobbin case.
A pivotted arm or latch 1 serves to hold the bobbin in its case, and is
also used in creating a tension for the shuttle thread, the said arm pressing upon
the bobbin by the force of a spring 2 lying in a slot in the edge of the shuttle, and
adjusted by a screw 3. The bobbin thread passes out of a delivery slot 4 near the
heel, then up through a holo 6 in the heel and between the arm 1 and the bobbin
(where it receives its tension), finally leaving the shuttle by passing up through
the hole 5 in said arm, which is at the centre of the shuttle's rotation. The holo 5
is considerably larger than the diameter of the thread delivered by it for a purpose
to be described.
Figures 11 and 12 show the delivered shuttle thread in different positions of the
shuttle. The needle hole in the work plate is not shown in these Figures, but it
will be understood that in Figure 12 it is just above the heel of the shuttle, the
said needle hole, the hole in the heel of the shuttle, and the delivery hole 5 being
in line. The shuttle thread between the fabric and the delivery hole 5 is now at
its shortest length, and the shuttle has completed its backward movement.
In Figure 11 the shuttle has moved forward far enough for its point to enter the
loop of the needle thread. The needle is now at its lowest position, and so also
is the take-up, and the feed is at its most remote position from contact with the
fabric.
The machine continuing its motion the shuttle enters the loop of the needle
thread, and turns in that loop a little more than a full revolution. The needle
starts up just before the shuttle has entered its loop, but the take-up being down
the needle thread remains slack while the shuttle passes on through the loop,
which it forms by drawing thread from the eye of the needle, the adjustable finger c¹
bearing against the periphery of the shuttle to keep down the lower side of the
loop while the shuttle passes through.
The finger c¹ is fastened to the lower side of the table and extends into the
shuttle race, and the shuttle is provided with a groove 7 near the lower edge of its
periphery into which the said finger projects. When the shuttle enters the loop,
or immediately after its point enters the loop, the finger e¹ catches the needle
tbread and holds it while the shuttle passes on, thereby preventing the loop from
being caught and broken by the point of the shuttle in its rapid rotation.
The rocking lever H has an eye a¹ placed nearly opposite the thread-tension
device b¹. The thread from the spool c¹ passes through this eye, then around or
about the tension device, then through a hole in an arm d' screwed to the lower
part of the head, then through the hole at the end of the take-up L, and to and
through the eye of the needle.
As the needle bar completes its descent the eye a¹ draws on the thread between
the tension device and spool, and draws off enough thread for a succeeding stitch,
and holds it in suspension between the tension device and spool ready to be drawn
therefrom by the action of the needle and take-up, thereby relieving these parts
from the work of turning the spool, which requires always a varying amount of
power, according to whether the spool is full or partially wound with thread.
When the said needle bar reaches its lowest position the take-up is also at its
lowest position, but the needle bar starting up to form the loop the take-up does
not start at once, but waits until the needle is just leaving the fabric. The move-
ment of the take-up, owing to the shape of the lower edge thereof, is slow at first
and then of increasing rapidity until the needle bar completes its upward motion,
at which time the take-up has taken up all the slack of the needle thread and set
the stitch.
During the latter portion of the rising of the aforesaid take-up the feed com-
mences to move the fabric, and by the movement of the fabric the needle thread is
drawn at the point attached to the fabric out of the line of the needle, but the feed
continues to operate until the needle bar has slightly descended. It then starts on
its downward and backward movement, the needle continuing its descent and
bringing down with it the take-up to give slack for a new loop.

page_text: When the point of the shuttle enters the loop of the needle thread, the hole 6 in
the heel of the shuttle, the delivery hole 5 in the latch and the needle hole are in
line, or nearly so, and but a small amount of thread has been drawn from the
bobbin t of the shuttle. At the time this thread is drawn from the shuttle the
distance from the hole 6 in the shuttle heel to the needle hole in the line of the
thread though the delivery hole 5 is greater than at any other position of the
shuttle.
The heel of the shuttle in its backward motion approaches the needle hole, and
when the needle is completing its rising motion and the feed is commencing to act,
the distance between the hole 6 in the shuttle heel and the side of the delivery
hole 5 next the needle, plus the distance from the same side of the delivery hole to
the needle hole, is less than the distance from the hole 6 to the needle hole when
in the direct line above described; consequently a little slack thread is formed in
the shuttle thread ready to be taken up by the needle thread to the centre of the
fabric when the fabric is moved by the feed, this movement drawing the shuttle
thread with it.
In other shuttle machines the length of thread is drawn from the bobbin by the
action of the feed to a distance equal to that between the last stitch, and the needle
hole and the thread is often subjected to too much strain when drawn up to the
centre of the fabric, and is broken; whereas by this Invention I form a little slack
in the shuttle thread prior to the movement of the fabric by the feed, and when
the feed takes place the thread is not strained, for enough thread to allow the fabric
to be fed has been drawn off, and is held slack for this movement of the fabric.
The delivery hole 5 in the arm 1 is at or near the centre of motion of the shuttle,
yet the hole is of a diameter greater than the size of the largest thread; and as the
shuttle changes from the position in which its hole 6 is in the direct line, heretofore
described, to the position in which that hole is nearly under the needle hole, the
quantity of slack then in the shuttle thread is increased by a length equal to the
distance between what would be the exact centre of the hole, if of the exact size of
the thread and that side of the hole next the needle hole. This distance and the
length of the slack thread in practice is about one-half the diameter of the delivery
hole 5 in the shuttle latch. This hole should be enlarged beyond the size of tho
thread to form slack for the shortest stitch and thinnest fabric, and for any
particular class of sewing; this hole in the latch may be so proportioned to the
thickness of the fabric as to give the slack desired.
Instead of a large holo at the centre of rotation, a small hole properly located at
one side of that centre, distant from it half the diameter of the large hole, will
accomplish the desired result.
When the shuttle has made slightly more than a full revolution the needle and
take-up are assuming their highest positions, and draw off and pull up the loop
from the heel of the said shuttle.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I claim,
First. The shuttle provided with a hole in its heel in combination with the
latch provided with a thread-delivery hole in line with the centre about which the
bobbin turns, but at the side of said centre, and larger than the diameter of the
thread to form the slack in the shuttle thread, as and for the purpose set forth.
Second. The rotary reciprocating shuttle provided with a hole in the heel and
with a bobbin-holding latch, having a thread-delivery hole central with the axis
about which the shuttle turns, and with a peripherical groove, in combination with
a stationary finger and an eye-pointed needle to hold the loop of the needle thread
and prevent its being broken by the shuttle, as above described.
Third. The shuttle and bobbin in combination with the latch, adapted to hold
the bobbin in place and produce tension thereon and the spring, as above
described.
Fourth. The shaft D, provided with a crank to actuate the needle mechanism,

page_text: in combination with mechanism for operating the shuttle carrier, consisting of the
crank, the link, the rack and pinion, and the shaft n, all connected and operating
as above described.
Fifth. The arm and its oye adapted to draw off thread between the spool and
tension device, in combination with the needle bar and needle and take-up, adapted
to be operated as described by the slot in the needle and roller, as above set
forth.
Sixth. A sewing machine, in which are embodied the above specified novel
devices, arranged in combination with the other parts shewn in the accompanying
O Drawings, and operating to perform their various functions in the working of the
said machine, as herein set forth.
In witness whereof, 1, the said William Robert Lake, have hereunto set my
hand and seal, this Twelfth day of April, in the year of our Lord One
thousand eight hundred and seventy-eight.