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(11) | EP 1 113 100 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Needle thread guide device for double chain stitch sewing machine |
| (57) A needle thread guide device for double ring stitch sewing machine is used for the
case that a double ring stitch is formed by forming a plurality of needle thread loops
below a fabric and allowing a looper to successively enter these needle thread loops.
The needle thread guide device has a cam (8c) which is formed at a location near a
thread receiving surface (8a) of a needle thread guide (8), so as to be integral with
the needle thread guide (8). The cam applies a tensile force, immediately before a
looper enters, to a needle thread loop (6Lr) of a left needle thread (6L) which the
looper enters finally in plural needle threads (6R, 6L) being received and supported
on the thread receiving surface (8a) of the needle thread guide (8), as a movable
needle thread take-up (3) rocks upward relative to rising movement of right and left
needles (1R, 1L) from a bottom dead point. With this construction, it is avoided that
the looper erroneously enters the plural needle thread loops, and a predetermined
stitch is therefore formed reliably without causing skip-stitch. |