Improvements in Sewing Machines.
Year: 1893

page_text: Date of Application, 12th June, 1893
Complete Specification Left, 10th Jan., 1894-Accepted, 17th Feb., 1894
PROVISIONAL SPECIFICATION.
Improvements in Sewing Machines.
I, ANNA SIEBERT, of Darmstadt, in the Empire of Germany, Gentlewoman,
do hereby declare the nature of this invention to be as follows :-
:―
This invention relates to improvements in the chain-stitch forming mechanism
used in the convertible lock-stitch' sewing machine forming the subject of previous
Letters Patent dated the 19th day of May 1891, No. 8580.
It has been found that the spur on the thread. looper hook impedes its motion,
and one improvement consists in dispensing with this spur and substituting therefor
a recess h made in the underside of the looper as shewn in Figures 1 and 2 of the
accompanying drawings so that the loop 6 of the needle thread lies in this recess
when it is spread so that the needle can pass through it.
In order to prevent the loop 6 slipping over the shoulder h¹, the looper H after
catching the loop b, that is to say when at about its middle position, remains
stationary until the thread is drawn tense by the usual mechanism and only then
continues its movement about the needle when the loop 6 has come against the
shoulder. This pause of the looper is effected by making the segment x-y
of
the cam concentric, as shewn in Figure 3.
In Figures to 6 another modification is shewn in which the looper H is bent
upwards and then obliquely downwards again. The loop is spread by the wide
rear bent-up portion of the looper H, and in order that the latter may not catch
the previous loop again a slightly bent-up offset B' is preferably provided on the
plate B which holds the preceding loop out of the way.
To allow for the upwardly-projecting bend of the looper, a recess A' is made in
the needle-hole plate, as shewn in Figures 7 and 8, to allow of ample room for the
free play of the looper and loop.
A further modification of the looper mechanism is shewn in Figures 9 to 12, in
which the looper H is duplex, the two looper hooks when in one position coming
close together, as shewn in Figure 11 and forming a single hook with a common
point. Directly the loop has been caught, the two hooks H H are moved apart on
their passage behind the needle, so as to spread the loop, as shewn in Figure 12.
The separation of the hooks is effected by mounting one of them upon a lever U
which strikes a stud V when the plate B is moved, the return movement being
produced by a spring k.
Figures 13 to 20 shew another form of looper differing in action both from that
in the previous Patent and the looper above described. This book does not itself
spread the loop, but catches and retains it, the spreading of the loop being effected
by a stud U provided preferably with a lip or flange projecting at one side. At
the forward movement of the looper H, one side of the loop catches against the
lug U and is thus spread by the notion of the looper hook H. On the return of
the hook the loop b is freed from the stud around which the book moves.
The dummy shuttle described in the previous Patent, for pushing the needle
thread loop into position to be caught by the looper, is dispensed with and in the
present arrangement the needle a only brings the thread slightly below the needle-
hole plate.
In order that the thread shall be caught with certainty by the looper H, the
needle a is turned to the right to the extent of about 45°, as shewn in Figures 16
and 19. The loop is thus formed directly beneath the needle hole plate A so that
the looper hook H, which lies directly below the latter, may catch the loop.

page_text: Figures 21 to 23 shew an improvement in the mechanism for imparting the
curvilinear motion to the looper carrier plate B. In order to impart to the looper
hook as rapid a motion behind the needle as possible so that it shall come to rest
as closely as possible behind the needle and the loop shall be as short as possible, a
second cam F¹ acting on the arm G¹ of a sliding rod connected to the looper
carrier B by means of a link H' moves the looper behind the needle, the return
movement being effected by a spring I. The plate B receives its to and fro motion
from a cam F as before.
The looper mechanism is thrown out of action by a lever M pivoted at L' when
moved to the dotted position N, Figure 22. The lever D is then held away from
the cam F, whilst the heel O on lever M acts on part P of arm G' and holds it
back from cam F¹, the looper hook being thus held stationary behind the needle
and out of action.
Dated this 12th day of June 1893.
ANNA SIEBERT,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.
Improvements in Sewing Machines.
I, ANNA SIEBERT of Darmstadt, in the Empire of Germany, Gentlewoman,
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 improvements in the chain-stitch forming mechanism
used in the convertible lock-stitch sewing machine forming the subject of previous
Letters Patent dated the 19th day of May 1891, No. 8580.
It has been found that the spur on the thread looper hook impedes its motion and
one improvement consists in dispensing with this spur and substituting therefor a
recess made in the underside of the looper, as shewn in Figures 1 and 2 of the
drawings accompanying the Provisional Specification, in which recess the loop 6 of
the needle thread lies when it is spread by the looper so that the needle can pass
through it. In order to prevent the loop 6 slipping over the shoulder ', the
looper H after catching the loop h, that is to say when at about its middle position,
remains stationary until the thread is drawn tense by the usual mechanism and
only then continues its movement about the needle when the loop 6 has come
against the shoulder. This pause of the looper is effected by making the
segment -y of the cam F concentric, as shewn in Figure 3. As in the previous
Patent referred to, the looper H is formed on a plate B which is guided by a stud
and slot C and is reciprocated through a lever D pivoted at E and held by a
spring G against cam F.
In Figures 4 to 6 another modification is shewn in which the looper H, formed
on plate B as before, is bent upwards and then obliquely downwards again. The
loop is spread by the wide rear bent-up portion of the looper H and in order that
the latter may not catch the previous loop again, an offset B¹ is preferably provided
on the plate B which holds the preceding loop out of the way, this offset being
slightly bent up as shewn in Figure 6 which is a cross-section on a-b Figure 4.
To allow for the upwardly-projecting bend of the looper, a recess A' is made in
the underside of the needle-hole plate A, as shewn in Figures 7 and 8, to allow of
ample room for the free play of the looper and loop.
A further modification of the looper mechanism is shewn in Figures 9 to 12 in
which the looper H is duplex, the two looper hooks when in one position coming close
together, as shewn in Figure 11, and forming a single hook with a common point.

page_text: Directly the loop has been caught, the two hooks H H are moved apart on their
passage behind the needle so as to spread the loop, as shewn in Figure 12. The
separation of the hooks is effected by mounting one of them upon a lever U which
is pivoted upon plate B so that the tail end of the lever U is caused to strike a
stud V, the return movement of lever U being produced by a spring k.
Figures 13 to 20 shew another form of looper differing in action both from that
in the previous Patent and the looper above described. This hook does not act
alone to spread the loop, but catches and retains it, the spreading of the loop being
effected with the aid of a stud U₁ provided preferably with a lip or flange projecting
at one side. At the forward movement of the looper H one side of the loop
catches against the lug U₁ and is thus spread by the motion of the looper hook H.
On the return of the hook the loop 6 is freed from the stud around which the hook
moves.
The dummy shuttle, described in the previous Patent, for pushing the needle
thread loop into position to be caught by the looper, is dispensed with and in the
present arrangement the needle a only brings the thread slightly below the needle-
hole plate.
In order that the thread shall be caught with certainty by the looper H, the
needle a is turned to the right, to the extent of about 45°, as shewn in Figures 16
and 19. The loop is thus formed directly beneath the needle hole plate A, so that
the looper hook H, which lies directly below the latter, may catch the loop.
Figures 21 to 23 shew an improvement in the mechanism for imparting the
curvilinear motion to the looper carrier plate B. In order to impart to the looper
hook as rapid a motion behind the needle as possible, so that it shall come to rest
as closely as possible behind the needle and the loop shall be as short as possible, a
second cam F', acting on the arm G' of a sliding rod connected to the looper
carrier B by a link H, moves the looper behind the needle, the return movement
being effected by a spring I. The plate B receives its to and fro motion from a
cam Fas before. The looper mechanism is thrown out of action by a lever M
pivoted at L when moved to the dotted position N, Figure 22. The lever D is
then held away from the cam F whilst the heel O on lever M acts on part P of
arm G' and holds it back from cam F', the looper hook being thus held stationary
behind the needle and out of action.
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 the sewing machine herein referred to, the improvement in the looper hook
which consists in providing the same with a recess in the underside terminated by
a shoulder in combination with means for making the looper pause at the middle of
its movement whilst the loop is drawn taut about it so as to prevent the loop
slipping over the hook, as specified.
2. In the sewing machine referred to, the looper formed with an upwardly bent
bow at the broad end and the point obliquely downwards, as specified with reference
to Figures 4 and 5, in combination or not with an upwardly inclined offset to hold
the preceding loop out of the way of the looper, as specified.
3. In the sewing machine referred to, a duplex looper formed of two hooks which
are brought together as one hook to engage the loop and caused to separate on
moving behind the needle so as to spread the loop open, one of said hooks being
formed on a lever pivoted on the carrier of the other hook, as specified.
4. In the machine herein referred to, the combination of a simple hook engaging
with the loop as described and a stationary stud having a laterally projecting lip or
flange with which stud the loop is engaged by the hook for the purpose of spreading
it and from which it is disengaged on its return movement, the needle being placed
in the position specified and carrying the loop only just below the needle hole
plate.
5. The combination, with the mechanism for imparting the longitudinal

page_text: reciprocating motion to the looper carrier, of the mechanism in substitution for the
curved guide lot and stud for imparting the lateral or curvilinear motion to said
carrier and moving the hook as quickly and closely as possible behind the needle,
as specified.
1004
ANNA SIEBERT,
By A. M. & Wm. Clark,
53, Chancery Lane, Loudon, Chartered Patent Agents.