Improvements in Chain-stitch Sewing-machines and Needles therefor.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements in Chain-stitch Sewing-machines and Needles
therefor.
I, FRIEDRICH JOHANN TROPE, of 36-37 Hohe Bleichen, in the City of Hamburg,
Germany, Merchant, do hereby declare the nature of this invention to be as
follows:-
The invention relates to apparatus for chain-stitch sewing, which is especially
intended for the sewing of coarser fabrics, such as sack-cloth, straw-cases for,
bottles and the like.
The apparatus comprises a needle so formed and operated as to be capable both
of acting as a needle and of taking the place of the loop-catcher and fabric-feeder.
The point of the needle, is, as in a crochet-needle, provided near its point with
a rigid-hook. Above the hook the needle-stem carries in a suitable slot a two-
armed lever, which is capable of moving about a pin fixed transversely in the
needle. A spring located in the slot tends to force the upper arm of the lever
somewhat out of the slot ad consequently to hold the lower arm of the lever
back in the slot, with the result that the mouth of the hook of the needle is open.
By means of a suitable mechanical driving device, the needle is, in this con-
dition, passed through a previously formed thread-loop and the fabric and drawn
out again, the sewing thread under which the hook has caught being carried
with it. In order that this may take place with certainty and, consequently,
that there shall be no missing stitches, the mouth of the needle hook is, during
the return of the needle, kept closed by the lever above referred to and for which
purpose the upper arm of the lever is forced against its spring into the needle-
slot, so that the lower lever-arm comes before and closes the mouth of the hook.
This movement of the lever is effected automatically by a special abutment,
for instance a small roller mounted in the machine frame close to the needle-stem
in such a position that it will be somewhat. above the lever when the needle
has passed through the fabric and assumed its lowest position. When the needle
is drawn up, the upper arm of its lever passes under the roller, and is by it forced
into the needle-slot, so causing the lower arm to move outwardly and close the
mouth of the hook. The lever remains in this position until the taken-up portion
of thread has been drawn through the fabric and the thread-loop.
The needle is then, by means of the driving mechanism of the machine, brought
into an inclined position, moving about an axis provided for the purpose, and
in this inclined position it again passes through the fabric. The upper arm of
the lever will however, in consequence of the inclined position given to the needle,

page_text: have come out of contact with the roller and the lower lever-arm will consequently
have moved into the slot in the needle and so uncovered the mouth of the needle
hook. Afterwards, the needle having, while in its depressed position, been
brought back into a vertical attitude, and thereby, acting as a fabric feeder, has
pushed the fabric forward, its hook again catches the thread and draws it upwards
through the fabric and the loop of thread as before.
Instead of holding back the lever from the mouth of the hook by a spring
during the descent of the needle through the fabric and during the ascent of the
needle holding it over the hook mouth by a stationary abutment, the arrangement
may, be reversed, a stationary abutment holding back the lever from the mouth
of the hook and a spring moving' and retaining the lever in the position in which
the mouth of the needle hook is closed.
Dated thi FAL
T
1004
COMPLETE SPECIFICATION.
Improvements in Chain-stitch Sewing-machines and Needles
therefor.
I, FRIEDRICH JOHANN TROPE, of 36-37 Hohe Bleichen, in the City of Hamburg,
Germany, Merchant, 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 chain stitch sewing machines and
needles therefor whereby such machines are rendered especially adapted for
sewing coarser fabrics, such as sack-cloth, straw-cases for bottles and the like.
The needle to be used in my improved sewing machine is so formed and
operated as to be capable both of acting as a needle and of taking the place of
the loop-catcher and fabric-feeder.
In the accompanying drawings,
Figure 1 is an end view, and
Figure 2-a side elevation of the improved sewing machine;
Figure 3 is a detailed view of the needle drawn to an enlarged scale and illus-
trating its operation;
Figure 4 is a plan of same;
Figures 5, 6 and 7 are detailed views, partly in section, of the improved needle.
Similar letters refer to similar parts throughout the several figures.
The point of the needle a is, as in a crochet-needle, provided with a rigid
hook a Above the hook the needle-stem carries in a suitable slot ba two-armed
lever c which is capable of oscillating or moving about a pin cl fixed transversely
in the needle. A spring d located in the slot 6 tends to force the upper arm of
the lever c somewhat out of the slot b and consequently to hold the lower arm
of the lever back in the said slot with the result that the mouth of the hook of
the needle is open.
The mechanical driving device for operating the needle consists, for instance,
of a rotating driving shaft i carrying an eccentric k. Around the latter is placed
a ring or strap to which is attached the needle carrier m into which the needle a
is fastened by any suitable means. Besides this the needle a is guided in a suitable

page_text: slot of a rocking bolt f movably journalled in the frame A of the machine. From
this arrangement it results that when the shaft i is rotated the needle a receives
not only a reciprocating up and down motion but also an oscillating movement
about its guiding pivot f, the purpose of which will be hereinafter described.
When the needle by its driving device is moved down it passes with its mouth
open (Fig. 6) through the previously formed loop h of the thread coming from
the feed roller h¹, and through the fabrics or the like. When the needle is drawn
out again, the sewing thread under which the hook a has caught is carried with
it. In order that this may take place with certainty and, consequently, that
there shall be no missing stitches, the mouth of the needle hook is, during the
upward movement or return of the needle, kept closed by the lever c, for which
purpose the upper arm of this lever is forced against its spring d into the slot b,
so that the lower lever-arm comes before and closes the mouth of the hook a
(see Fig. 7).
This movement of the lever c is effected automatically by a special abutment,
for instance a small roller e mounted in a suitable arm e¹ of the machine-frame
close to the needle-stem in such a position that it will be somewhat above the
lever c when the needle has passed through the fabric and assumed its lowest
position. When the needle is drawn up, the upper arm of its lever c passes
under or against the roller e, and is by it forced into the needle-slot b, so causing
the lower lever arm to move outwardly and close the mouth of the hook a².
The lever cremains in this position until the taken-up portion of the thread has
been drawn through the fabric and the thread-loop.
The needle a is then by means of the driving mechanism, in this instance by
the aid of the eccentric k, brought into an inclined position (see dotted lines
Fig. 3), moving or turning about the guide and pivot-bolt f provided for this
purpose. The upper arm of the lever c will, however, in consequence of the
inclined position given to the needle, have come out of contact with the roller e,
for which purpose the arm el carrying the said roller is open or slotted at its
respective sides (see Fig. 4) so that the needle can swing freely into the inclined
position. The lever c being no longer acted upon by the roller e will consequently
have moved its lower arm into the slot in the needle and so uncovered the
mouth of the needle hook. In this inclined position the needle with its hook
opened, is passed down through the thread-loop and the fabric. Afterwards, the
needle having, while in its depressed position, been brought back into a vertical
attitude, and thereby acting as a fabric feeder, has pushed the fabric forward
along under the presser foot n, its hook al again catches the thread and draws it
upwards through the fabric and the loop of thread as before.
Instead of holding back the lever c from the mouth of the needle through the
fabric and during the ascent of the needle holding it over the hook mouth by
a stationary abutment, the arrangement may be reversed, a stationary abutment
holding back the lever from the mouth of the hook and a spring moving and
retaining the lever in the position in which the mouth of the needle hook is closed.
Having now particularly described and ascertained the nature of the said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:-
1. The herein described improved sewing machine for sewing coarser fabrics
in which the passing of the thread caught by the needle through the fabric and
the thread loop is effected by means of a hooked needle that is provided with a
lever c which is caused by an abutment, spring or the like to close the hook of
the needle during its ascent and to leave the hook open during the descent of the
needle respectively, substantially as and for the purpose set forth.
2. In a sewing machine the combination of a reciprocating and oscillating
hooked needle having a lever arranged in a slot in its stem, with means for
operating the said lever in the manner described, substantially as and for the
purpose specified.

page_text: 3. My improved sewing machine as described and shown in the accompanying
illustrative drawings.
Dated this 5th day of August 1897.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.