US 7,458,326 B2Granted

Overlock sewing machine

AssigneeBrother Kogyo Kabushiki Kaisha

InventorsMatsuo Yamaguchi, Hiroki Hayashi

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Abstract

An overlock sewing machine including a main shaft rotated by a sewing machine motor; a vertically moving sewing needle and an overlooper and an underlooper respectively driven by the rotation of the main shaft; a single looper drive shaft forming overlock stitches in cooperation with the overlooper, the underlooper and the sewing needle and rotated by the rotation of the main shaft, shaft line thereof being arranged perpendicularly to the main shaft; and a swing generating member having first and second swing generating portions fixed to the looper drive shaft for swinging the overlooper and the underlooper respectively; a first and second swing link mechanisms, both of which extend perpendicularly to the looper drive shaft, swinging the overlooper and the underlooper by conveying the drive force generated by the first and second sewing generating portions.

Claims15

Dependent claims

An overlock sewing machine forming overlock stitches by swinging an overlooper and an underlooper in synchronization with a vertical movement of a sewing needle, the overlock sewing machine comprising:

a main shaft rotated by a sewing machine motor and vertically driving the sewing needle;
a looper drive shaft having a shaft line perpendicular to the main shaft and rotated by the rotation of the main shaft;
a swing generating member fixed to the looper drive shaft and having a first swing generating portion for swinging the overlooper and a second swing generating portion for swinging the underlooper;
a first swing link mechanism arranged in a direction perpendicular to the looper drive shaft and swinging the overlooper by conveying thereto a drive force generated by the first swing generating portion;
and
a second swing link mechanism arranged in a direction perpendicular to the looper drive shaft and swinging the underlooper by conveying thereto a drive force generated by the second swing generating portion,
wherein the first swing generating portion comprises a crank pin eccentric with respect to the looper drive shaft, and the second swing generating portion comprises an eccentric ring eccentric with respect to the looper drive shaft;
the swing generating member being integrally provided with the crank pin and the eccentric ring.

5 more elements

An overlock sewing machine forming overlock stitches by a swinging movement of an overlooper and an underlooper in synchronization with a vertical movement of a sewing needle, the overlock sewing machine comprising:

a main shaft rotated by a sewing machine motor and vertically driving the sewing needle;
a looper drive shaft having a shaft line perpendicular to the main shaft and rotated by the rotation of the main shaft;
a swing generating member fixed to the looper drive shaft and having a first swing generating portion for swinging the overlooper and a second swing generating portion for swinging the underlooper;
a first swing link mechanism arranged in a direction perpendicular to the looper drive shaft and swinging the overlooper by conveying thereto a drive force generated by the first swing generating portion;
a second swing link mechanism arranged in a direction perpendicular to the looper drive shaft and swinging the underlooper by conveying thereto a drive force generated by the second swing generating portion;
a switch mechanism switching the underlooper from a sewing position to a threading position which is outside a swing range at the time of sewing and in which threading of a threading eyelet in a distal end of the underlooper and a thread engagement to the thread engagement portion in a base end of the underlooper can be performed externally;
and
a returning mechanism automatically returning the underlooper from the threading position to the sewing position upon sewing start.

5 more elements

Dependencies are inferred from the claim text.