Sewing – Stitch forming – Chain or double chain
Reexamination Certificate
2002-06-10
2004-11-09
Izaguirre, Ismael (Department: 3765)
Sewing
Stitch forming
Chain or double chain
C112S122100
Reexamination Certificate
active
06814015
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a looper and a cutter drive mechanism for sewing machine, and more particularly to a looper and a cutter drive mechanism for sewing machine which can perform lock stitching and over-edge stitching integrally and further can perform such stitchings by changing over an operation which performs the over-edge stitching in the lock stitching by cutting a fabric edge and an operation which performs the lock stitching without cutting the fabric edge.
BACKGROUND OF THE INVENTION
Conventionally, as the most fundamental stitch formed by a sewing machine among stitches formed by joining a plurality of fabrics or the like, a lock stitching is known. In the lock stitching, when an upper thread which is made to pass through a needle is made to penetrate the fabric along with the vertical movement of the needle, by intercepting the upper thread with a loop-taker point of a rotary hook which accommodates a lower thread so that the upper thread and the lower thread are crossed with each other to form the lock stitching whereby a plurality of fabrics are securely joined along the stitch.
On the other hand, as the stitching which can prevent unraveling of peripheral portions of the fabrics or the like which are liable to be disintegrated, an over-edge stitching is known. In the over-edge stitching, depending on the number of threads for forming the stitch and the number of needles which perform an approximately vertical movement relative to a fabric surface, there have been known a single-needle two-thread over-edge stitching (U.S.A. Stitch standard: Stitch type 503), a single-needle three-thread over-edge stitching (U.S.A. Stitch standard: Stitch type 504), and further a two-needle five-thread stitching (U.S.A. Stitch standard: Stitch type 516) which combines a chain stitching and the over-edge stitching and is usually called an interlock.
However, in such an over-edge stitching, to form stitches, a thread is intercepted from side by two hook-shaped needles called loopers or looper threads which move horizontally are intercepted by needles. In this manner, since the looper threads do not cross in the direction perpendicular to the fabric surface with respect to the needle thread, it is impossible to securely join the fabrics as in the case of the lockstitching. That is, there arises a so-called “laughing” phenomenon in which when two fabrics joined by the over-edge stitching are opened, the stitching threads are exposed outside. Accordingly, in performing the over-edging after joining a plurality of fabrics, it is necessary to form the stitch (U.S.A. Stitch standard: Stitch type 517) by performing the lockstitch.
In such a stitch (U.S.A. Stitch standard: Stitch type 517), although it is desirable that the lockstitch portion and the over-edge portion are disposed as close as possible to each other, the lockstitch requires a rotary hook to accommodate a lower thread below the needle which performs the vertical movement, while the over-edge stitching requires loopers which move to cross a locus of the vertical movement of a needle which is provided separately from the needle of the lockstitching and hence, there naturally exists a limit with respect to the respective positions of the lockstitch portion and the over-edge stitching portion. In view of the above, sewing machines which can be used for both of the lockstitching and the over-edge stitching have been proposed in Japanese Patent Publication 15268/1981, Japanese Patent Publication 25145/1985, Japanese Patent Publication 25396/1986 and the like. However, all of the sewing machines disclosed in these publications are sewing machines which selectively use one of these functions and it has been impossible to perform the lockstitching and the over-edge stitching simultaneously in a state that the lockstitching and the over-edge stitching are disposed close to each other.
On the other hand, methods in which the lockstitching and the over-edge stitching can be performed simultaneously have been proposed as disclosed in Japanese Laid-open Patent Publication 113490/1980, Japanese Laid-open Patent Publication 136085/1980, Japanese Laid-open Patent Publication 146190/1980, Japanese Laid-open Patent Publication 122495/1988 and the like. However in these proposals, with respect to the over-edge stitching, since the loopers which cross the locus of the vertical movement of a needle and are provided separately from the lockstitching adopt the looper movement of the above-mentioned conventional over-edge stitching as their movement, the lockstitching requires a rotary hook to accommodate the lower thread below the needle which performs the vertical movement and the over-edge stitching requires the loopers which performs their movement such that the movement crosses the locus of the vertical movement of the needle provided separately from the lockstitching. Accordingly, there naturally exits a limit with respect to the positions of the over-edge stitching and the lockstitching and it has been difficult to perform the lockstitching and the over-edge stitching simultaneously in a state that the lockstitching and the over-edge stitching are disposed close to each other in terms of the mechanism of the sewing machine.
Further, a lockstitching/over-edge stitching attachment (manufactured by TOYO SEIKI KOGYO KABUSHIKIGAISHA, product name “RUBYLOCK”) which simultaneously performs the lockstitching and the over-edge stitching has been proposed (Japanese Patent Publication 2541601). As shown in
FIG. 27
, this attachment is used in a form that it is fixedly mounted on a fabric presser rod
1001
. A drive arm
1003
a
of a crank
1003
journalled in an attachment frame
1002
is driven by a needle rod (not shown in the drawing) which carries a needle
1011
. A driven arm
1003
b
rocks an upper looper drive plate
1005
supported on the attachment frame
1002
by way of a drive connection link
1004
. Due to the rocking of this upper looper drive plate
1005
, an upper looper
1007
supported on the attachment frame
1002
by way of an upper looper drive link
1006
is rocked. On the other hand, due to this rocking of the upper looper drive plate
1005
, a pin
1005
a
mounted on the upper looper drive plate
1005
in a protruding manner slides in and along a groove
1008
a
formed in a lower looper drive plate
1008
journalled in the attachment frame
1002
and rocks this lower looper drive plate
1008
. Due to this rocking of the lower looper drive plate
1008
, a lower looper
1010
journalled in the attachment frame
1002
is rocked by way of a lower looper drive link
1009
. In such an attachment structure, since the upper looper
1007
must intersect the needle
1011
on the upper surface of a fabric (not shown in the drawing), the upper looper
1007
is inclined in a left upward direction as seen from the fabric feeding and advancing direction. Further, since the lower looper
1010
must intersect the needle
1011
on the lower surface of the fabric, the lower looper
1010
is inclined in the left downward direction as seen from the fabric feeding and advancing direction. Further, the upper and lower loopers
1007
,
1010
are inclined such that the upper and lower loopers
1007
,
1010
interloop each other at a side of the fabric end of the fabric.
In the drawing, numeral
1014
indicates a needle stitching portion of the needle
1011
, numeral
1012
indicates a thread tension equipment and numeral
1013
indicates a looper thread take-up driven by the lower looper drive plate
1008
.
In the attachment having such a constitution, when the needle bar performs the upward and downward movement, the lockstitching is formed by the needle thread (not shown in the drawing) which passes through the needle
1011
and the lower thread (not shown in the drawing) accommodated in a rotary hook (not shown in the drawing). Simultaneously, the drive arm
1003
a
of the crank
1003
is driven by the needle bar and the driven arm
1003
b
rocks the upper looper drive plate
1005
by way of the drive connection link
1004
.
Izaguirre Ismael
Lorusso, Loud & Kelly
Suzuki Manufacturing, Ltd.
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