Stitch line forming method

Patent metadata

Field	Value
Publication number	US-9879366-B2
Application number	US-201514753553-A
Country	US
Kind code	B2
Filing date	Jun 29, 2015
Priority date	Aug 4, 2014
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

While feeding an upholstery member, a sewing needle is reciprocated to form needle receiving holes, and an upper thread is passed through each needle receiving hole, caused to cross a lower thread, and pulled out of the needle receiving hole. The sewing cycle is repeatedly performed to form a stitch, so that stitches form a stitch line in a surface sheet. A direction of a force, which is generated by applying tension to the lower thread and which acts to rotate thread ends of a pair of adjacent stitches in each needle receiving hole about a crossing part of the upper thread and the lower thread, is defined as a rotation direction. The sewing needle is rotated in a direction opposite to the rotation direction to incline a diagonal line of the quadrangular shape forming the cross section relative to the feeding direction of the upholstery member.

First claim

The invention claimed is:

1. A stitch line forming method comprising:
preparing an upholstery member and a sewing machine, wherein the sewing machine has a sewing needle having a quadrangular cross section in a plane parallel to a plane of the upholstery member, the quadrangular cross section of the sewing needle has two pairs of opposite corners, the quadrangular cross section of the sewing needle defines a pair of imaginary diagonal lines inside the quadrangular cross section between respective pairs of the two pairs of opposite corners of the quadrangular cross section, an upper thread, a lower thread, and a feeding direction in which the upholstery member is fed, wherein the upholstery member has a back face and a front face opposite to the back face;
forming the stitch line, by performing a sewing cycle, in which, while the upholstery member is fed in the feeding direction, the sewing needle is reciprocated in a thickness direction of the upholstery member, and the sewing needle is positioned with respect to the feeding direction so that at least one of the imaginary diagonal lines between respective pairs of the two pairs of opposite corners of the quadrangular cross section of the sewing needle is inclined relative to a line extending in the feeding direction, to form needle receiving holes in the upholstery member,
wherein each one of the needle receiving holes has two pairs of opposing corners, and each one of the needle receiving holes has two diagonal lines between respective pairs of the two pairs of opposing corners, and the imaginary diagonal lines between respective pairs of the two pairs of opposite corners of the quadrangular cross section of the sewing needle correspond to the two diagonal lines between respective pairs of the two pairs of opposing corners of the needle receiving holes, at least one of the two diagonal lines of the needle receiving holes is inclined relative to the line extending in the feeding direction,
wherein, for each one of the needle receiving holes, the upper thread passes from the front face of the upholstery member to the back face of the upholstery member, the upper thread crosses the lower thread located on the back face of the upholstery member, the upper thread passes back to the front face of the upholstery member through the each one of the needle receiving holes, and the upper thread extends to the front face of the upholstery member from one of the two pairs of opposing corners corresponding to the one of the two diagonal lines which is inclined relative to the line extending in the feeding direction, for the each one of the needle receiving holes; and
applying a tension to the lower thread, the tensioned lower thread acts on the upper thread which extends from the one of the two pairs of opposing corners of the one of the two diagonal lines of each of the needle receiving holes, to reduce an inclination, relative to the feeding direction, of the one of the two diagonal lines of each of the needle receiving holes.

2. The stitch line forming method according to claim 1 , wherein the sewing needle is reciprocated with the one of the imaginary diagonal lines between respective pairs of the two pairs opposite corners of the quadrangular cross section of the sewing needle being inclined by an angle in a range from 10° to 20° relative to the feeding direction in which the upholstery member is fed.

3. The stitch line forming method according to claim 1 , wherein the upholstery member is formed only of the surface sheet.

4. The stitch line forming method according to claim 1 , wherein the upholstery member includes the surface sheet and a cushion layer laminated on a back face of the surface sheet.

5. The stitch line forming method according to claim 1 , wherein the quadrangular cross section of the sewing needle is at a distal end of the sewing needle where the quadrangular cross section passes through the upholstery member, and the quadrangular cross section is at an imaginary plane perpendicular to the axis of the distal end of the sewing needle.

6. The stitch line forming method according to claim 5 , wherein the quadrangular cross section of the sewing needle that passes through the upholstery member has a diamond shape.

7. The stitch line forming method according to claim 1 , wherein, during the forming of the stitch line, a plane of the quadrangular cross section of the sewing needle is parallel to a plane of the upholstery member.

8. The stitch line forming method according to claim 1 ,
wherein the quadrangular cross section of the sewing needle has a diamond shape, and the opposite corners of one of the two pairs of opposite corners of the quadrangular cross section of the sewing needle have acute angles,
wherein, for each one of the needle receiving holes, the opposing corners of the one of the two pairs of opposing corners have acute angles and are offset relative to the feeding direction, and the upper thread is located in the acute angles.

9. The stitch line forming method according to claim 1 , wherein in the step of forming the stitch line,
each of the imaginary diagonal lines between the respective pairs of the two pairs of opposite corners of the quadrangular cross section of the sewing needle is inclined relative to the feeding direction, and
wherein, for each of the needle receiving holes formed in the upholstery member, each of the opposing corners of the two pairs of opposing corners is offset relative to the feeding direction.

10. The stitch line forming method according to claim 9 ,
wherein the quadrangular cross section of the sewing needle that passes through the upholstery member has a diamond shape, and the opposite corners of one of the two pairs of opposite corners of the quadrangular cross section of the sewing needle have acute angles,
wherein, for each of the needle receiving holes formed in the upholstery member, the opposing corners of the one of the two pairs of opposing corners from which the upper thread extends have acute angles, and the upper thread is located in the opposing corners of the one of the two pairs of opposing corners which have acute angles.

11. The stitch line forming method according to claim 1 , wherein in the step of forming the stitch line, each of the needle receiving holes has four flat inner wall surfaces.

12. The stitch line forming method according to claim 1 ,
wherein in the step of forming the stitch line,
the at least one of the imaginary diagonal lines between the respective pairs of the two pairs of opposite corners of the quadrangular cross section of the sewing needle is inclined by an angle in a range from 10° to 20° relative to the line extending in the feeding direction, and
for each of the needle receiving holes formed in the upholstery member, the opposing corners of at least one of the two pairs of opposing corners are offset relative to the feeding direction, and the upper thread extends from the opposing corners which are offset relative to the feeding direction.

13. The stitch line forming method according to claim 8 ,
wherein in the step of forming the stitch line,
the at least one of the imaginary diagonal lines between the respective pairs of the two pairs of opposite corners of the quadrangular cross section of the sewing needle is inclined by an angle in a range from 10° to 20° relative to the line extending in the feeding direction, and
for each of the needle receiving holes formed in the upholstery member, the opposing corners of at least one of the two pairs of opposing corners are offset relative to the feeding direction, and the upper thread extends from the opposing corners which are offset relative to the feeding dir

Assignees

• Toyoda Gosei Kk

Inventors

• Toda Minoru
• Totani Chiharu
• Inagaki Ryota

Classifications

• D05B93/00

  Stitches; Stitch seams · CPC title

• D05B1/12

  Lock-stitch seams · CPC title

• D05B15/04 Primary

  for lock-stitch work (D05B15/08 takes precedence) · CPC title

• D05B1/08

  for making multi-thread seams · CPC title

• D05B1/00

  General types of sewing apparatus or machines without mechanism for lateral movement of the needle or the work or both · CPC title