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Two-thread lock-stitch sewing machine with thread cutter

Imported: 24 Feb '17 | Published: 06 Jan '04

Johann Enns, Andreas Riffel

USPTO - Utility Patents

Abstract

A two-thread lock-stitch sewing machine with a thread cutter comprises a shaft which is parallel to the vertical axis of a shuttle and has a lever arm with a thread pulling knife disposed on it. The bobbin case in the shuttle has a holding finger which is directed toward a stitch hole and is held between two cams that are arranged on a rib. Formed between the cams and the workpiece bearing plate is an interspace which the lever arm passes through, together with the thread pulling knife projecting into a space between the motion travel of the sewing needle and the cams so that a thread cutting operation is enabled to be performed with very short thread tail pieces remaining on the lower side of the workpiece. The thread cutting operation excels by simple design and reliable operation.

Description

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an elevation of a sewing machine;

FIG. 2 is a plan view, on an enlarged scale, of a portion of the sewing machine in accordance with the arrow II of FIG. 1, with a lever arm of a thread cutter being shown in a swung-out position;

FIG. 3 is a view, corresponding to FIG. 2, with the lever arm of the thread cutter being shown in a swung-in position;

FIG. 4 is a perspective view of the lever arm shown in FIGS. 2 and 3;

FIG. 5 is a perspective explosive view of a workpiece bearing plate and a holding plate;

FIG. 6 is a view, rotated clockwise by 90°, in the direction of the arrow VI of FIG. 2 on the workpiece bearing plate and the holding plate in the mounted condition;

FIG. 7 is a perspective view of a bobbin case on an enlarged scale;

FIG. 8 is an enlarged illustration, in the direction of the arrow VIII of FIG. 2, of components that are essential for the invention, with portions of the components being shown in section; and

FIG. 9 is a perspective view of a one-piece component with a workpiece bearing plate and a holding plate.

Claims

1. A two-thread lock-stitch sewing machine, comprising:

2. A two-thread lock-stitch sewing machine according to claim 1, wherein the rib is formed as a bilaterally clamped support.

3. A two-thread lock-stitch sewing machine according to claim 2, wherein the plate (

47) and the bearing plate (

16) are provided with congruent drilled holes (

58,

59;

60,

61) for the reception of fastening screws (

14,

15).

4. A two-thread lock-stitch sewing machine according to claim 1, wherein the rib (

46′) is formed on the bearing plate (

16′).

5. A two-thread lock-stitch sewing machine according to claim 4, wherein the rib (

46′) is formed as a bilaterally clamped support.