IMPROVEMENTS IN SEWING MACHINES
Year: 1860

page_text: PROVISIONAL SPECIFICATION left by Alfred Vincent Newton at the
Office of the Commissioners of Patents, with his Petition, on the
15th November 1860.-A communication from abroad by Dwight Tracy,
of Worcester, in the State of Massachusetts, and United States of
America.
I, ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Mechanical Draughtsman, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN SEWING MACHINES," to be
as follows:-
This Invention relates to certain means of controlling the needle thread of
a sewing machine, whereby the quantity supplied to the needle is caused to be
always in proportion to the thickness of the cloth or other material being
sewn, and to the length of the feed movement, and a uniform tightness of
stitch is produced whatever variation may occur in the thickness of the
material, or however the feed movement may be varied, or whatever may be
the relative sizes of the needle and thread, obviating entirely the necessity of
any manual adjustment for the needle thread. It also relates to certain means
of controlling the shuttle thread, whereby it is caused to be drawn to a uniform
tightness in the cloth or other material, whatever may be the quantity of thread
on the bobbin, or from whatever part of the bobbin the thread may be drawn.
It further relates to the forming of a knotted stitch of peculiar character.
The apparatus for controlling the needle thread consists of two levers, which
are arranged at a short distance behind the rocking needle arm. One of

page_text: these levers, which from its carrying a switch for a purpose to be presently
explained, may be called the switch lever, has a limited horizontal movement
toward and from the needle arm, and transversely to the planes of motion
thereof on a fulcrum pin attached to the stationary arm of the machine.
A portion of this lever is bent downward in a curved form corresponding with
the arc described by the needle, and the so curved portion has in the side
nearest the centre of motion of the needle arm a curved groove, that is fitted
with a switch, which works on a pivot that attaches it to the lever. This
The
groove is intended to receive a pin carried by a stud on the needle arm.
switch is kept open at top by a spring bearing on its lower part. Below the
switch, and immediately below the opening of the groove, there is a wedge-
like projection on the front of the lever. The switch lever has attached to the
back of its upper part a small clamp, consisting of two small jaws set at a
short distance apart, one of the jaws being rigid and the other elastic, and a
tongue-like piece hinged to the lever below the jaws, so as to be capable of
pressing the needle thread between the jaws, and holding it there by the
pressure of the elastic jaw. The upper part of the tongue enters a fixed eye
attached to the stationary or supporting arm of the machine, and a small set
screw passed through the stationary arm bears against the tongue. The other
lever of the thread controller, which may be termed the take-up lever, consists
of a thin piece of plate metal, with a wire thread guide attached, and is
arranged between the needle arm and switch lever to move in planes parallel
with the planes of motion of the needle arm on a fixed pin, which attaches it
to the stationary arm. This take-up lever operates in combination with a
stop-piece attached to the switch levers. A stationary thread guide, having an
eye at its end, and secured to the stationary arm, completes the apparatus for
controlling the needle thread, whose operation is as follows:-The thread
passes from the spool between the tongue and jaws under the lower part of the
guide upward to and around the upper part of the guide, from whence it
passes to and through the eye of the take-up lever, and from thence to the eye
of the stationary guide, whence it descends to the needle. During the descent
of the needle arm the pin which it carries works in the switch of the switch
lever, but during the ascent of the needle arm it is caused to pass up outside
the switch owing to the lower part of the switch being closed. The pin as it
passes down the switch pulls forward the switch lever and opens the clamp,
but as the needle completes its descent the pin passes out of the switch, and
passing on the projection of the said lever below the switch forces back the
lever and closes the clamp again. The stud of the needle arm as it ascends
operates on the curved adjacent edge of the take-up lever, moving it towards

page_text: the spool, but in its descent it leaves that lever under the control of a friction
spring interposed between it and the switch lever, which should produce upon
it an amount of friction less than the friction produced on the thread by the
stationary thread guide. As the needle descends the friction of the spring
holds the take-up lever with sufficient force to keep the thread taut enough
for the eye of the needle to slide freely down it; but when the eye enters the
cloth and begins to take the thread double through it, the lever will be drawn
toward the thread guide until it strikes the stop on the switch lever, and is
prevented moving any further, when (the clamp still being open) the continued
descent of the needle draws off thread from the spool until its pin strikes the
projection before mentioned, pushes back the switch lever,. and- causes the
tongue of the clamp to effect the clamping of the thread. During the rise of
the needle and the extension of the loop of its thread by the shuttle the
take-up lever is allowed a further movement in the same direction, as above
explained, to give sufficient thread to enable the loop to be extended to a
proper size for the shuttle to pass through. As the needle continues to rise;
the lever is moved in the opposite direction, or toward the spool, and caused to
take up the slack thread, the thread still remaining clamped by the jaws and
tongue.
back part of
The shuttle thread is carried by a bobbin applied to the shuttle in the usual
manner, and the shuttle is furnished internally with a stationary guide bar;
running nearly the whole length of the bobbin. It is also provided with a
take-off lever and a clamping piece. The guide bar is attached to the back of
the shuttle, and the take-off lever is attached by a fulcrum pin to the top of
the shuttle. This lever has thread holes in one end, situate nearly opposite
the middle of the length of the bobbin, and has a fixed stop provided for its
other end within the shuttle, to prevent its moving too far inward. The
clamping piece is an elbow lever, which rocks on a fulcrum attached to the
top of the shuttle. One arm extends some distance along the
the shuttle, near the eye at which the thread leaves the shuttle.
thread passes from the bobbin back under the guide har over the bar to one
of the holes in the take-off lever, thence back round the fixed guide bar to
another eye in the take-off lever, and thence between the clamping piece and
the inside of the shuttle, and through the eye thereof. The quantity of thread
thus provided between the bobbin and the eye of the shuttle constitutes a
reserve from which the thread is taken to make the stitches without drawing
from the bobbin, the drawing of the thread from the bobbin being effected by
an operation independent of that of forming the stitch. On the front or flat
side of the shuttle race there are provided two stationary thin and nearly flat
The shuttle

page_text: pieces of metal, with bevelled edges, which project a short distance into the
race, and are at such a height that the top of the interior of the shell of the
shuttle will just pass over them in the movement of the shuttle; and notches
are provided in the shell, near the end of the shuttle, to enable it to pass over
the said pieces, which are arranged in such positions relatively to the length
of the raceway that the outer end of the clamping piece will just pass under
one or other of them as the shuttle arrives near the end of its movement in
either direction, and may thereby be depressed sufficiently to cause its back
part to clamp the thread against the interior of the shell close to the eye, so
that by the continued movement of the shuttle the stitch may be tightened
in a positive manner. The shuttle, however, moves far enough to leave the
clamp free again at the time its movement is completed. Near the pieces
which project into the raceway there are in the front of the raceway two
recesses, with oblique faces, so arranged that the free end of the take-off lever
is capable of entering one of them when the shuttle is at the end of its move-
ment in either direction.
The operation of the thread controller is as follows:-The shuttle having
passed through the loop of the needle thread, and arrived near the end of its
stroke in one direction, the outer end of the clamping piece passes under one
of the stationary projecting pieces which causes the clamping piece to act on
the thread, and clamp it close to the eye of the shuttle. The clamping takes
place just before any strain comes on the portion of the thread between the
eye and the cloth, and just before the loop. of the needle thread is drawn tight,
so that by the continued movement of the shuttle its thread may be drawn
tight at the same time as the loop of the needle thread. At the time of the
thread being thus drawn tight the take-off lever is lying nearly parallel with
the length of the shuttle, but as the shuttle in completing its movement
passes far enough for the clamping piece to be freed, the shuttle thread is
liberated from the clamp, and the draft produced upon it by the continued
movement of the shuttle causes a small portion of the thread that is between
the bobbin and the eye to be drawn out owing to the take-off lever having less
friction upon it than the bobbin. The quantity of thread thus drawn out is
only enough to be drawn into the cloth in making a stitch, but the feed now
taking place, while the shuttle is stationary, causes the drawing out of a further
portion equal to the length of the feed movement, thus completing the quantity
necessary to form a stitch. This drawing out of the thread draws the per-
forated end of the take-off lever into the shuttle, and causes the other end to
enter the recess in the race. During the return of the shuttle the clamping
piece is caused again to clamp the thread, and the projecting end of the

page_text: take-off lever coming in contact with and passing along the inclined side of
the recess while the thread is so clamped, is forced into the shuttle, causing the
other end to be moved outward, and to draw off as much thread from the
bobbin as has just previously been drawn out through the eye, the clamp
preventing the slack thread outside of the eye from being drawn in again.
The clamping piece is more especially applied to the shuttle with a view to
the production of the knotted stitch, which will now be described, and for
making the ordinary shuttle stitches the take-off lever can be used in com-
bination with the usual mode of producing friction on the shuttle thread by
passing it through a number of holes in the shell of the shuttle.
The means to effect the knotting of the needle and shuttle threads consists
principally of the clamping piece, one of the projecting pieces in the shuttle
race, and an elastic fork, working above the cloth; this fork is for the purpose
of entering and spreading loops of the shuttle thread, which are drawn up
through the cloth by the needle thread. The fork is attached to a slide,
which is fitted to slide horizontally in a slot in the stem of the presser. The
two prongs of the fork are elastic, and their inner sides turn outwards in an
upward direction from the lower edges, which remain in close contact when
no force is applied to separate them. The straight edges of the prongs
terminate in two short, sharp points, which are parallel on their inner sides
but bevelled in opposite directions on their outer sides, so as to be capable of
closing and operating together like a single point in entering the small loops
of shuttle thread, which are drawn up through the cloth. The upper parts of
the prongs serve to guide the loops of shuttle thread to the points. A pin
on the slide which carries the fork enters an upright slot in the lower end of
the switch lever before mentioned, by which the said fork is caused to receive
a short longitudinal movement parallel or nearly so with the feed movement
of the cloth. The points of the fork are directed forward or in the opposite
direction to the feed movement, and are so situated as to cross the path of the
needle in their movement, and when the presser is down upon the cloth, the
fork just rests on the upper surface of the same. During the whole of each
ascending movement of the needle, and during a portion of its descending
movement, the fork is stationary with its points some distance behind the
needle, but immediately after the descent of the needle commences, and before
the point of the latter arrives at the surface of the cloth, the fork is caused to
advance quickly by the movement of the switch lever to such a position that
the needle to enter the cloth must force apart and pass between its prongs.
The fork only remains in this advanced position till the needle has passed a
short distance through the cloth, and is then drawn back again. During each

page_text: descent of the needle following every second movement of the shuttle, the
points of the fork enter a loop of the shuttle thread, which has been drawn up
through the cloth by the tightening of the needle thread, owing to the clamping
piece not having been brought into operation, and the shuttle thread having
consequently been left slack while the needle thread was tightened. The
advance of the fork takes place simultaneously or nearly so with the feed
movement of the cloth in the opposition direction, and the loop is drawn
lengthwise over the surface of the cloth. The needle then descends between
the prongs of the fork, forces them apart, and so spreads the loop laterally and
passes through it. By the repetition of the above described operations a
series of knotted stitches is produced, two operations of the needle and a
movement back and forth of the shuttle being required to produce every
stitch.