Improvements in Shuttles for Sewing Machines.
Year: 1898

page_text: Improvements in Shuttles for Sewing Machines.
I, HARRIET RUTH TRACY, of 58, Brondesbury Villas, Maida Vale, in the County
of London, Gentlewoman, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention relates to sewing machines, and particularly to that class in which
a revoluble shuttle or loop-taker is employed, and in which the loop of the meedle-
thread is engaged by the loop-taker, and is carried entirely around the same to
enclose a second or lower thread to form a lock stitch; or in which one loop of a
needle-thread is engaged by the loop-taker and is carried through a preceding loop
to form a chain-stitch, or when also engaged with a lower thread, a lock-chain-
stitch.
In sewing machines of this class I have hitherto employed a revoluble loop-
taker or shuttle having three loop-engaging hooks, or one having two series of
three hooks each. In practical operation I find that a shuttle having this number
of hooks will operate satisfactorily where thin or medium thick fabric
is sewed, but, where heavy, thick fabric, cloth or other fabric is sewed, I
find that the loops of the needle thread will not be drawn up tightly against the
underside of the fabric, owing to the fact that the needle enters the fabric before
the loop is properly taken up and binds the resulting thread in the needle-opening,
resulting in the formation of a succession of loop-stitches or loops depending from
the underside of the fabric. If, to overcome this defect, the tension is increased,
the result will be either that the thread will break or that more thread. will be
drawn from the spool, the latter result tending to increase the size of these loose
loops.
The cause of this defect in the proper taking up of the loop of the needle-thread
is due to the fact that the needle reciprocates too rapidly with relation to the
rotation of the shuttle, or in other words, the shuttle does not rotate a sufficient
distance between the formation of the stitches to allow adequate time for the proper
taking up of the successive loops. In shuttles such as above referred to, having
three hooks, or two series of three hooks each, the shuttle makes but two-thirds of a
revolution to complete a stitch, so that the loop of the needle thread does not have
time to pass the vertical diameter of the shuttle, before the needle again begins to
descend to make a succeeding stitch, thereby leaving the loop of the shuttle in a
relaxed position when this succeeding stitch is begun, resulting in the formation
of the loose stitches or loops on the under side of the cloth above referred to.
It will be obvious that if the needle be so timed with reference to the shuttle
that the latter will have rotated sufficiently to take up the slack of the loop of the
needle thread before the needle enters the fabric to make a succeeding stitch and to
draw sufficient thread from the upper spool to make the stitch in any thickness of
cloth, that the formation of the loose loops will be entirely overcome, whether the
fabric be thick or thin.

page_text: '
To this end therefore my invention has for its object to effect the proper and
complete taking up of the loops of the needle before a succeeding stitch is formed.
With this object in view the invention consists in the combination with a
reciprocating eye-pointed needle, of a revoluble loop-taker, arranged adjacent to
the needle, the loop-taker being provided on its periphery with four hooks, by which
the succeeding loops of the needle thread are engaged, and the thread of each
preceding loop is taken up.
For forming a lock stitch the four loop-engaging hooks point in a direction to
engage the needle-thread loop, when the shuttle is revolved in one 'direction rela-
tive to the feed of the fabric to be sewn; to form a chain or a lock-chain stitch,
the said hooks are pointed and the shuttle revolved in the opposite direction relative
to this feed, and interchangeable shuttles are provided according to the stitch
desired to be formed. Or the two series of four hooks may be arranged on a single
shuttle.
In the accompanying drawings forming part of this specification, and in which
like. letters of reference indicate corresponding parts,
"
Figures 1, 2 and 3. are detached views of the shuttle and needle in operative
relation to. a piece of fabric during the formation of a lock stitch..
Figures 4 and 5 are similar views during the formation of a chain stitch; and
Figures 6 and
during the formation of a lock chain stitch.
Figure 8 is a perspective view of a four hook shuttle;
Figures 9 and 10 are a side and end view of a reversible shuttle having two
series of loop engaging hooks, and
Figures 11 and 12 are details of alternative forms of hook receiving and retain-
ing devices.
Referring to the drawings generally, A is the shuttle or loop-taker, comprising
a central receptacle A' forming the cop or bobbin receiving case, and an annular
or substantially annular needle receiving groove A2 (as shown in Figure 10) formed
in the periphery thereof at one side of the median line, which groove is adapted
for receiving the point of the needle during its reciprocation. Or instead of a
groove one side of the outer edge of the shuttle may be cut away, as shown in
Figure 8, in which case a throw-off" bar A³, is provided to prevent the back part
of the needle thread loop when engaged by a hook catching on the edge A* of the
bobbin case A'. The throw-off bar must be placed as close behind the hook as
possible, consistently with its avoiding contact with the needle when the latter
is in its lowered position.
The periphery of the looptaker is likewise provided with 4 or 8 loop-receiving
openings A, one wall or side of each opening terminating in a loop engaging
hook a, a, a2 etc., the other wall or side is formed with a blunt loop retaining pro-
jection b, directed outwards so as to guide the loop out of the path of the loop
engaging hook, and avoid any danger of the loop being caught in the same, before
it is drawn completely up to the fabric. The loop receiving openings A6 and their
retaining projections b may be varied in shape, the essential point is that the loop
should be retained during the major portion of a revolution of the shuttle but
readily released approximately on the completion of the revolution so as to be
drawn up close to the under side of the fabric.
The loop retaining projection b may be formed as shown in Figures 1 to 7, so as
to release the loop before the full completion of a revolution. It is sometimes,
however, desirable especially when thin fabric is being worked, to delay the release
of the loop until the revolution is fully completed, or even till after its completion;
in these cases the loop receiving opening A6 is so shaped that its projection b is
overlapped by the loop-engaging hook a, as shown in Figure 11: or it may even
take the form of a bar b¹ extending right across the loop receiving opening and
preferably curved outwards so as to carry the loop well out of the path of the loop
engaging hook as shown in Figure 12. Conveniently the bar 6 would be con-
tructed so as to be fixed in, instead of being formed integral with the rest of the
shuttle, and it is evident that it can be made adjustable, and the receiving open-

page_text: ing A likewise provided with a projection 6, so that the bar can be used when very
light fabric is to be worked, and removed for heavier fabric when an earlier release
of the loop is desirable.
The bobbin or cop case A' is provided with an opening or openings e c', and a
tension device 2 for the bottom thread, when such is employed.
i
The loop-taker or shuttle A is supported by rollers or other convenient device,
adjacent to an ordinary eye-pointed reciprocating needle, and receives rotary motion
through suitable mechanism not necessary to be shown.
In Figures 1, 2 and 3, a, a¹, a², a³, are the four loop-engaging hooks designed
to engage the loops of the needle thread as the same are brought down through the
cloth and the work plate of the machine, and bare the loop-retaining projections
designed to retain the loops of the needle thread until the same are carried around
the loop taker to enclose a lower or shuttle thread, and then brought to a position
approximately beneath the needle to form a lock-stitch. In order that each
succeeding loop of the needle thread formed may properly take up each preceding
loop, the loop taker is so arranged with reference to the needle that the loop taker
performs three-quarters of a revolution in each descent of the needle, and the
needle is so timed with reference to the rotation of the shuttle that the preceding
loop of the needle thread is taken up before the needle enters the fabric to make a
succeeding stitch. This timing of the needle with reference to the rotation of the
shuttle is found to be of great value, in that it allows ample time for the taking
up of each loop before a succeeding loop is taken, thereby preventing the forma-
tion of loops or loose stitches on the under side of the fabric.
In Figures 1, 2 and 3 the shuttle rotates in the direction indicated by the arrow
shown thereon, the work being fed in the direction of the arrow placed above it.
In Figure 1 the parts are shown in the positions assumed as the first loop of the
needle thread is engaged by one of the engaging hooks of the loop-taker.
In Figure 2 the first loop has been carried approximately three-fourths around
the loop-taker, a second loop of the needle thread being about to be engaged by
the loop taker, the needle having been drawn up through the cloth, the cloth fed,
and the needle driven down to form a second loop, and
1
Figure 3 shows a completed stitch, the second about to be drawn up into the
cloth, and the third loop shown engaged by the loop taker.
Figures 4 and 5 show the parts in two positions during the formation of a chain
stitch. In this case the loop engaging hooks a¹ a5 a6 a7 are on the right hand side
or wall of the receiving opening, and the loop engaging projections 6 on the left;
the shuttle being rotated, as indicated by the arrow in the opposite direction to
that shown in Figures 12 and 3 when forming a lock stitch; the work is fed in
the same direction in both cases.
Figure 4 shows the hook a engaging the second loop of the 'needle thread to
carry it through the first loop, which has been carried approximately three-
fourths around the loop-taker and is about to be released to be drawn up to the
cloth, and
Figure 5 shows a completed stitch, the loop of the second stitch carried partly
around the loop taker.
Figures 6 and 7 are similar views to Figures 4 and 5, but show the employment
of a lower thread to form the lock-chain stitch. In this case the relative move-
ments of the needle and shuttle are the same as in the formation of the chain stitch.
Instead of employing two interchangeable shuttles, one for forming a lock stitch
and the other for forming a chain or a locked chain stitch, I may employ a loop
taker or shuttle such as is shown in Figure 9, in which two series of loop engaging
hooks are provided, each series comprising four hooks, a a¹ a² a³ and a4 a5 a6 a7
respectively, the hooks of the same series being arranged equidistant relative to
each other, the hooks of the two series alternating with each other and pointing
in opposite directions, so that when the loop taker is revolved in the direction of
the arrow d, the hooks a a¹ a² a³ of one series, will engage the loops of the needle
thread to form one kind of stitch, say a lock stitch, and when revolved in the

page_text: opposite direction, as indicated by the arrow e, the hooks at a a a' of the other
series, will engage the needle thread to form a stitch of a different character say
a chain or locked chain stitch. The action of the loop-taker relative to the needle
is similar to that described with reference to Figures 1 2 and 3 when the shuttle is
revolved in the direction of the arrow d, the hooks a a¹ a² a³ then engaging the
needle thread, whilst when revolved in the direction of the arrow
hooks a¹ as a a² engage the needle thread in a similar manner to that shown and
described with reference to Figures 4, 5, 6 and 7.
e the
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. The combination with a reciprocating eye pointed needle of a revoluble loop
taker arranged adjacent to the needle, the loop taker being provided on its
periphery with four loop engaging hooks, by which the succeeding loops of the
needle are engaged and the thread of each preceding loop taken up the looptaker
being so timed with relation to the needle that a loop is entirely drawn up into
the cloth or fabric by the looptaker before the needle enters the fabric to make
another stitch substantially as described.
2. The combination with a reciprocating eye pointed needle of a revoluble loop-
taker arranged adjacent to the needle, the loop taker being provided with two
sets or series of loop engaging hooks, each set comprising four hooks the hooks of
one set being oppositely disposed relatively to the hooks of the other set, and each
-hook of each set having a separate and independent loop receiving opening con-
tiguous thereto substantially as described.
3. In a revoluble loop-taker for sewing machines a throw off bar A³ substantially
as and for the purpose described.
4. In a revoluble loop taker for sewing machines having a peripheral loop-
receiving opening forming the loop retaining projection on one wall of the open-
ing beneath and to one side of the loop engaging hook of the other wall of the
opening substantially as described with reference to Figure 11 of the accompany-
ing drawings.
5. In a revoluble loop taker for sewing machines having a peripheral loop-
receiving opening, a loop-retaining bar substantially as described.
Dated this 1st day of November 1898.
HARRIET RUTH TRACY.
Boult & Wade,
Agents for the Applicant.