Decorative stitch type and method of and apparatus for producing same

A new stitch type and a method of and an apparatus for making same in which the loop is passed through the fabric through one hole and is returned through another hole and then is passed around a thread supply eye so that the body of the loop engages a single strand of the thread which twists around this loop and is drawn into the second hole. Such pairs of holes are spaced along the seam so that on one side of the fabric the stitches are spaced apart, i.e. the thread is alternately visible and invisible whereas on the opposite side the thread is continuously visible.

FIELD OF THE INVENTION 
My present invention relates to a structurally effective decorative or 
ornamental stitch type, to a method of producing the new stitch type and 
to an apparatus or sewing machine mechanism for carrying out the method, 
i.e. for producing the new stitch type. 
BACKGROUND OF THE INVENTION 
It is known to produce stitches which are generally described as 
interlooped stitches, from a single thread by forming a loop and drawing 
this loop around adjacent portions to other stitches, in effect to form a 
chain or chain-like structure. 
The variety of such stitches is manifold and the present invention is 
particularly concerned with one class of such stitches in which the thread 
is alternately visible and invisible on one side of the fabric and appears 
to be visible continuously along the seam on the opposite side of the 
fabric, i.e. the one side of the fabric shows the thread in spaced apart 
stitches which do not appear to be interconnected at this side of the 
fabric. It is such a stitch type having thread loops reaching over to this 
side of the fabric and wherein the thread is alternately visible and 
invisible i.e. wherein the loops appear to be spaced apart without any 
connection, that is the concern of this invention. 
Two such stitch types, by way of example, are stitch type 104 (chain 
stitch) of the Federal Standard No. 751a and stitch type 209 (saddler and 
row stitch). Similar stitches are recognized in the German Industrial 
Standard DIN 61 400. 
In the formation of such stitches, on one side of the fabric there appears 
to be a free space between the successive stitches, a construction which 
has ornamental advantages and which gives the appearance of hand 
stitching. Such stitch types are widely used in the garment industry, 
especially when particularly esthetic or ornamental results are desired 
with a stitch seam which nevertheless is effective for the fixing of parts 
of the garment together or for other structural purposes. 
The chain stitch 104 is sewn with the aid of two mutually parallel 
juxtaposed needles, a factor which makes the passage of the seam around 
corners or with angular portions difficult to achieve neatly. 
Furthermore, the spacing between the holes in the fabric spanned by each 
visible stitch is fixed by the distance between the needles and thus 
either cannot be altered or can be altered only with considerable 
difficulty. In addition, the individual stitches formed by the loop which 
passes through one hole or piercing and a successive hole or piercing, is 
not locked within one of these holes or otherwise firmly anchored, but 
rather each loop is merely chained to the next loop on the underside of 
the fabric so that upon breakage or release of an end of the seam, 
raveling or loosening of the entire stitch seam may occur. In many ways, 
therefore, this stitch seam cannot be utilized for structural purposes, 
i.e. for holding two parts tightly together, but must be treated as a 
purely decorative stitch seam. 
Stitch type 209 has other disadvantages. Firstly, it must be formed with a 
yarn of limited length, generally 1.5 m, which limits the length of the 
seam which can be sewn. When the thread is expended, the sewing machine 
must be stopped and a new thread introduced in a highly time-consuming and 
inconvenient operation. 
In German Pat. DE No. 26 38 264, there is described an apparatus for 
forming stitch seams with the stitch type 209, but in the formation of 
such stitches there is always the danger that the fabric will be crimped 
or bunch up when tension is applied to the thread. This again is because 
the individual stitches are not truly locked together or secured. 
There are, of course, other stitch types in which the stitches are firmly 
locked against these disadvantageous phenomena, but such stitches do not 
have the esthetic appearance of stitch types 104 and 209. 
OBJECTS OF THE INVENTION 
It is, therefore, the principal object of the present invention to provide 
an improved stitch type wherein the stitches at one side of the fabric are 
spaced apart, utilizing a looped single thread, whereby the disadvantages 
of earlier stitch types with a similar appearance are obviated and, in 
particular, the stitches can be used for securing purposes as well as 
decorative elements, and the stitch seam can be formed without 
interruption of the sewing operation even for comparatively long seams. 
Another object of this invention is to provide an improved method of making 
the new stitch type referred to above whereby the danger of bunching of 
the fabric with the application of tension to the thread is excluded and 
the continuous sewing length is not limited by the factors mentioned 
above. 
It is also an object of this invention to provide an improved apparatus for 
producing the new stitch type and carrying out the aforementioned method. 
SUMMARY OF THE INVENTION 
These objects and others which will become apparent hereinafter are 
attained, in accordance with the present invention with a stitch type in 
which between pairs of holes formed in the fabric, a single strand of the 
continuous thread extends on one side of the fabric while from this side 
of the fabric at one hole of each pair a loop of the thread passes through 
the fabric over the other side thereof and back through the other hole of 
the pair, being looped around the single strand as it runs from a previous 
stitch to the first-mentioned hole of this pair and such that a bight or 
sinuous formation or twist is formed in the single thread at the second 
hole of this pair. 
Surprisingly the formation of this bight in the single thread serves to 
lock the stitches or retain them against raveling even if an end of the 
thread is raveled or the thread is cut or broken at some location along 
the seam, and while the fact that the loop passes around the single strand 
of the thread ensures, at least in part, a freedom from bunching or 
crimping even with the application of high levels of tension to the 
thread. It is important that the twisting of the loop and the single 
strand be effected at the second hole of each pair and it is even more 
advantageous when the twist is drawn into the second hole by the tension 
of the thread during sewing of the seam so as to lie close to but inwardly 
up the underside of the fabric. 
According to the invention, therefore, the thread forming the stitch type 
is passed in a single strand through the apex or bight of the returning 
thread loop so that it forms a shallow bight or twist, i.e. so that it is 
twisted with this loop. 
According to a method aspect of the invention, a thread portion protruding 
from a thread supply located at the side of the fabric which is to have 
the continuous stitch appearance, is clamped firmly and between the 
retained part and the thread supply, a loop of the thread is formed. This 
loop is drawn by an open-eye needle through the fabric to the other side 
thereof through the first of the holes of each pair of holes formed by the 
passage of the needle through the fabric, the thread loop is then returned 
to the first-mentioned side of the fabric by the needle on a new pass 
through the fabric to form the second hole of the pair and the loop now on 
the first-mentioned side is drawn around the thread supply to pass it over 
the single strand of the thread and the thread is tensioned or the loops 
are drawn tight so that sinuous bight or bend is formed in the single 
strand to define the aforementioned twist. 
An apparatus for the purposes described preferably includes the 
aforementioned needle which can be mounted on a needle bar at the opposite 
side of the fabric, a thread-loop catcher operated synchronously with the 
needle for drawing out the requisite length of thread from the supply, 
means, i.e. appropriate tools for inserting the thread into the eye and 
control means for controlling the thread during the formation of the loop 
and the movement of the loop in the manner described. A rotary or 
oscillating thread-loop catcher can be provided beneath the fabric to 
guide the thread loop around the entire thread supply, spool or bobbin and 
when the thread supply is a coil or bobbin, this thread-loop catcher may 
be a rotary member adapted to orbit the coil and preferably is rotatable 
about the axis thereof. 
When the thread supply is provided on a shuttle, the thread-loop catcher is 
so oriented that it can open the thread loop so that the shuttle can pass 
a single strand of the thread through this loop. 
Various control means for the loop can include fingers, hooks or the like 
for retaining and pulling the loop and can be pivotal and synchronized 
with the operation of the needle. 
An eye-closing member can be mounted with lost motion on the needle so that 
it is intercepted by the fabric as the needle passes through the latter to 
open the eye. This prevents accidental engagement of the fabric in the eye 
.

SPECIFIC DESCRIPTION 
FIGS. 1-9 show the formation of the new stitch type and will be used to 
elucidate not only the method of fabrication, but also the details of the 
structure of the new stitch type. 
However, reference should be made first to FIG. 14 which illustrates the 
new stitch type in highly diagrammatic form. 
The fabric workpiece has been represented at T and the upper surface T' can 
be considered to be the visible surface of a garment while the lower 
surface T" can be deemed to be an inner surface thereof. The stitch seam 
is formed by a single thread 1 which is stitched through the fabric 
workpiece. The latter can, of course, represent several layers which are 
stitched through by the seam and thus are mechanically held together by 
the row of stitches. 
In the formation of the row of stitches, a succession of holes will be 
formed in the workpiece by the sewing machine needle. These holes can be 
treated as paired. For example, one hole H' can be paired with a second 
hole H". The spacing between the holes of the pairs and the spacing 
between the pairs of holes can all be varied utilizing conventional 
stitching techniques because the hole spaces are not dependent upon two 
fixedly positioned needles. 
A loop 6 of the thread 1 extends from the underside T" through each hole 
H', passes over the upper surface T' and then passes back through the hole 
H" of the pair, the bight 8 of this loop then passing around a single 
strand 1' of the thread which can have a twist or sinuous bend 1" around 
the bight. This twist can be drawn into the bight. 
Consequently, on the upper side T' of the fabric, stitches S alternate with 
free spaces F at which the thread is not visible. On the opposite side of 
the fabric, in the region corresponding to the free spaces F, the single 
strand 1' bridges the stitches. 
Referring now to FIGS. 1-9 in some detail, it will be apparent that the 
ornamental seam to be sewn in the single layer or multilayer fabric T 
utilizes a single thread 1 which, in the usual manner, originates from a 
coil 2. On the exposed surface of the fabric, the ornamental seam is seen 
to consist of the thread 1 which is alternately visible and invisible on 
this side and which is continuously visible, i.e. appears to be 
uninterrupted on the underside. 
The coil 2 in the embodiment of FIGS. 1-13, is arranged in a manner known 
in the art in a rotating thread loop catcher comprising a coil support 3 
which is provided with hooks. The thread catcher or loop catcher of this 
member 3 orbits the axis of the spool 2 and has been shown at 7 in FIGS. 6 
and 7 although it has been omitted from the other Figures under discussion 
here for the sake of clarity. 
Alternatively (see FIG. 15) the coil 202 can be provided on a shuttle 203 
forming the coil carrier and which is reciprocated as represented by the 
shuttle actuators 203a and 203b in the direction of the arrow 203e and 
thereby caused to pass through a loop 1'" of the single thread 1. The 
passage of the shuttle through this loop will be seen to be analogous to 
the passage of the loop of the fixedly located coil 2. Alternatively the 
coil 2 can be accommodated in an oscillating coil support with hooks. When 
the shuttle is used, of course, the tip of the shuttle can catch and widen 
the thread loop and the additional hooks 203c and 203d need not be used. 
In the system of the invention the seam length is not limited commonly for 
any given garment because the machine can stitch a seam of a length 
corresponding to the entire thread supply on the coil 2 or 202. 
Interruption of the operation of the sewing maching during the formation 
of a seam is therefore not common. 
As can be seen from FIG. 1, moreover, the underside 104 with a laterally 
open eye 106 can be mounted on a needle bar on the head of the sewing 
machine which overhangs the fabric T and can be part of a sewing machine 
arm with the usual cam drive, the machine also having the usual dogs for 
advancing the fabric on a stitch plate which can support the fabric above 
the spool 2. 
The loop 6 of a previous stitch (FIG. 1) is gradually released by a finger 
118 on the upper surface of the fabric as a hook 121 engages the tread 1 
between the spool and the previous stitch to displace it in the direction 
of the arrow C and draw out a new loop on the underside of the fabric. The 
thread portion is thus held in place or retained by the previous stitch. 
When the formation of the seam is to be commenced, this thread portion is 
held in place by the fingers of the operator against the fabric or is 
clamped against the fabric by other means. 
When the needle 104 traverses the fabric (FIG. 2), it swings past a tool 
112 for inserting the thread 1 into the open eye of the needle. As the 
needle 4 is drawn upwardly (compare FIGS. 3 and 4), the thread 1 is pulled 
up to form a new thread loop on the side of the material T facing away 
from the coil 2 (FIG. 4). 
Then the material T is shifted in the direction of arrow A and the loop 6 
is engaged by the finger 118 which serves to draw out the loop as the hook 
121 returns in the opposite direction. The advance of the fabric in the 
direction of arrow A can be effected by the feed dogs or some other fabric 
transport mechanism (FIG. 5). 
The needle 104 then pierces the fabric (FIG. 6) to form the second hole H" 
of the pair, at a location spaced from the hole H' by a variable distance. 
At the same time the rotating gripper 7 or hook of the coil support, which 
orbits the axis of the coil or bobbin 2 as noted, enters the loop 6 
adjacent the needle 104 and spreads this loop while separating it from the 
eye of the needle. 
As the needle retracts, while hook 121 recedes to the left and the finger 
118 moves to the right, the gripper 7 sweeps the loop 6 around the entire 
coil 2 (FIG. 7) and the thread supply of this coil. 
Slack in the yarn may be taken up by a member P which can shift parallel to 
the fabric and closely overlies the latter. 
Once the loop 6 has been carried around the thread supply 2, the finger 118 
again draws the loop out above the fabric, thereby drawing the bight 8 
(FIG. 8) around the strand 1' between the hole H' and the thread supply. 
This completes the formation of the visible stitch portion 5. 
Following an additional feeding step in the direction of arrow A of the 
fabric T, the position shown in FIG. 1 is reached and the stitch-forming 
process can be repeated. 
As can be seen from FIG. 14, not only is the bight in engagement with the 
single strand 1' of the thread, but the sinuous 1" which engages over the 
bight 8 is twisted thereon so that the pulling up of the single thread or 
the pulling down of the loops to release the stitches is not possible. 
While tension on the thread may tighten the threads and compress the 
fabric, it will not cause serious bunching or crimping. It is, of course, 
advantageous for the twist to be drawn up slightly into the hole H" of 
each pair. 
As can be seen from FIG. 13, a sewing machine 101 comprises the usual arm 
102 of the machine frame and can have a needle bar (not shown) mounted 
thereon for vertical displacement in the usual manner. The dog and stitch 
plate are also not shown in this Figure. 
From FIG. 10 it will be apparent that the needle 104 has a pointed tip 105 
and laterally open eye 106, as well as a longitudinal groove 108 which 
crosses the mouth of the eye. A pressure part 109 of the needle can be 
mounted with lost motion thereon so that it is entrained upwardly by the 
needle but is intercepted by the upper surface of the fabric T as the 
needle pierces the fabric so that a tongue 107 guided in this groove 108 
is retracted from the mouth of the eye after the eye is disposed below the 
stitch plate 110. This prevents the eye 106 from catching in the fabric. 
From this illustration, moreover, it can be seen that the fabric T can 
consist of a plurality of layers which are sewn together. 
Referring now to FIGS. 11 and 13, it will be apparent that, in addition to 
the loop catcher 3, it also serves as the bobbin support and can be driven 
synchronously with the needle, the tool 112 below the stitch plate and 
fabric can comprise an arm 112a with a slot 112b for engaging the thread 
and carrying it across the needle to fit it into the eye. The arm 112a is 
pivotally mounted at 112c on a support 102a of the machine and can be 
angularly displaced synchronously with the needle movement via a rod 112d. 
Thus the operating rhythm of the tool 112 is synchronized not only with 
the needle 104 but also with the support 3. 
Below the fabric and the stitch plate, the hook 121 is carried on a control 
means represented generally at 114 and comprising an arm 120 which can be 
pivotally displaced about the shaft D synchronously with the needle and 
the coil support by means not shown. 
The arm 118 is carried by another control means 117 above the fabric and 
provided for controlling the thread loop during the formation of the 
stitch. This control means (FIGS. 12 and 13) comprises a clamp 119 or the 
arm 118 at the end of a lever 125. 
The lever 125 can be a double-arm lever fulcrummed on the machine frame 102 
and articulated at its arm opposite that provided with the clamp 119 to a 
lever 123 whose cam follower 116 rides in a cam 115 driven by the arm 
shaft (not shown) in the usual manner and is thus synchronized with the 
needle bar and the loop catcher 3. The lever 123 is in turn pivotally 
mounted at 123a upon the machine frame. 
The lever 123, the rocker 122 and the lever 125 together form a backgear 
lever mechanism which increases the pivotal range of the hook 118. The 
operation of the machine can be appreciated not only from FIGS. 9-13 but 
also with reference to FIGS. 1-9. 
For example, the hook 118 of the upper control means 114 holds the loop 6 
of the thread firmly (FIG. 1), and at the beginning of a new stitch 
forming the process with the fabric C in position, begins to move in the 
direction of arrow B under the control of the backgear lever mechanism 
operated by the cam 115. During this movement, the hook 120 pivots in the 
direction of arrow C with one phase of the angular oscillation of the 
shaft 130, thereby picking up the quantity of thread loop 6 released by 
the finger 118 (FIG. 2). 
In the position shown in FIG. 3, the finger 118 has competely released the 
thread loop 6 which is now engaged by the needle 104 and the thread loop 
is drawn by the inserter 112 into the open eye. Shortly before the needle 
has reached its lower dead-center position, the pressure part 109 has come 
to rest upon the fabric and is held back so that the continued movement of 
the needle effectively retracts the tongue 107 sufficiently to clear the 
eye and allow the insertion of the thread. 
The balance of the operation of the machine has already been described in 
connection with the formation of the stitches. It need only be mentioned 
that the coil 2 of the thread supply can be braked in the holder 3 so that 
only the amount of thread required is in each case withdrawn from the coil 
and the thread never significantly slackens. 
It should also be apparent that the system can work with a needle whose 
needle bar is reciprocated from the side on which the thread supply is 
located or with a double-pointed needle cooperating with two holding means 
which pass the needle between them from one side of the fabric to the 
other. The control means 114 is used to tighten the stitches as they are 
formed and thus to draw the twist somewhat into the hole H".