Claims
- 1. A stitch forming mechanism for forming a flat seam in a workpiece formed of multi-layers of material comprising:
- two needles reciprocating in a vertical plane and each carrying a needle thread,
- a throat plate having a work supporting surface lying in a horizontal plane and having openings for passage of said needles therethrough,
- two loopers disposed beneath said throat plate for cooperation with said needles to form two parallel rows of stitches, each looper carrying a looper thread,
- a spreader operating above said throat plate for casting a cover thread into loops that lay on opposite sides of said two needles when said needles penetrate said workpiece, and
- a cover thread assist member connected to a mid portion of said spreader, and cooperating with said spreader to form said cover thread loops in a configuration for penetration, on both sides of said cover thread, by said two reciprocating needles.
- 2. The invention as set forth in claim 1 wherein said cover thread assist member is constructed of a hardened wire that is connected to said spreader by silver solder.
- 3. The invention as set forth in claim 2 wherein said hardened wire has a diameter of about 0.05 inches.
- 4. The invention as set forth in claim 1 in which said stitch forming mechanism further includes a thread guide plate fixed in a position closely overlying said spreader, and a thread eyelet mounted above said thread guide plate for movement with said needles vertically toward and from said thread guide plate, said thread guide plate having an arcuate shaped slot formed therein, said cover thread extending downwardly through said eyelet, through said arcuate shaped slot, across the path of said spreader and then down to the previous stitch, the combined motions of said spreader, said cover thread assist member and said eyelet relative to said arcuate shaped slot causes said cover thread to slide between positions at opposite ends of said arcuate shaped slot to thus direct said cover thread to follow a serpentine path between said two needles.
- 5. The invention as set forth in claim 4 wherein said cover thread assist member is constructed of a hardened wire that is connected to said spreader by silver solder.
- 6. The invention as set forth in claim 5 wherein said hardened wire has a diameter of about 0.05 inches.
- 7. A method of forming a stitch along and over the raw edge of a first workpiece that is laying in overlapped relationship to a second workpiece comprising the steps of:
- passing a first needle thread through the workpieces at points spaced along a line substantially parallel to said raw edge to form a first series of thread loops;
- passing a second needle thread through the second workpiece along the raw edge of the first workpiece and parallel to said first needle thread to form a second series of thread loops, said second needle leading said first needle and it's tip being elevated relative to the tip of said first needle such that said second needle penetrates the workpiece after penetration by said first needle;
- interlocking a first looper thread through said first series of thread loops;
- interlocking a second looper thread through said second series of thread loops; and
- laying a cover thread over the top surface of the workpiece such that said cover thread interlocks with each stitch formed by said first and second needle threads, the end of said cover thread that is not interlocked in stitches already formed being referred to as it's free end, wherein the invention comprises the steps of:
- (a) oscillating a spreader that has a free end and a mid portion through the stitch forming area during each stitch cycle, said spreader having a notch formed in said free end and a cover thread assist member connected to said mid portion,
- (b) engaging said cover thread with said spreader notch such that a loop is formed and moved to the area below said first needle;
- (c) passing said first needle thread through said loop;
- (d) engaging said cover thread with said cover thread assist member causing the free end of said cover thread to be carried toward and forward of said second needle such that said second needle penetrates the workpiece behind the cover thread.
- 8. A sewing machine for producing a stitch comprising two rows of closely and equally spaced stitches, each row of stitches formed from a needle thread and a looper thread, and wherein the mechanism for producing this stitch includes:
- a reciprocating needle bar;
- a throat plate having feed dog openings formed therein;
- a feed dog including material engaging portions adapted to extend through said feed dog openings to advance the material in the direction of material feed;
- a needle head mounting two needles, said two needles laying in a vertical plane and the point of the right needle being at a higher elevation than the corresponding point of the left needle;
- said needle head being secured to said needle bar such that said vertical plane of said needle head is at an acute angle to the direction of material feed;
- a looper rocker, mounted to pivot about an axis that is parallel to said direction of material feed, said looper rocker carrying two loopers, each arranged to cooperate with one of said needles and each having a looper point;
- the looper point, of the looper arranged to cooperated with the left needle, being spaced from the looper point of the looper arranged to cooperate with the right needle, by an amount corresponding to the spacing between the left and right needles; the point of the looper arranged to cooperate with the right needle is located in the vertical direction further from the looper rocker axis than the points of the loopers arranged to cooperate with the left needle;
- a spreader, having a notch formed at its free end and a cover thread assist member connected to a mid portion of the spreader, arranged to oscillate through the stitch forming area and contact and control a cover thread causing it to interlock with each stitch formed by said first and second needle threads.
- 9. The invention as set forth in claim 8 wherein the point of the looper that is arranged to cooperate with the right needle is elevated about 1/8 of an inch above the looper rocker axis than is the point of the loopers that is arranged to cooperate with the left needle.
- 10. The invention as set forth in claim 8 wherein said cover thread assist member is constructed of a hardened wire that is connected to said spreader by silver solder.
- 11. The invention as set forth in claim 10 wherein said hardened wire has a diameter of about 0.05 inches.
- 12. A sewing machine for producing a stitch comprising, two rows of closely and equally spaced stitches, each row of stitches being formed from a needle thread and a looper thread; and a cover thread interlaced with the two rows of stitches; wherein the mechanism for producing this stitch includes:
- a reciprocating needle bar;
- a throat plate having feed dog openings formed therein;
- a feed dog including material engaging portions adapted to extend through said feed dog openings to advance the material in the direction of material feed;
- a needle head mounting two needles, said two needles laying in a vertical plane and the point of the right needle being at a higher elevation than the corresponding point of the left needle;
- said needle head being secured to said needle bar such that said vertical plane of said needle head is at an acute angle to the direction of material feed;
- a looper rocker, mounted to pivot about an axis that is parallel to said direction of material feed, said looper rocker carrying two loopers, each arranged to cooperated with one of said needles and each having a looper point;
- the looper point, of the looper arranged to cooperated with the left needle, spaced from the looper point of the looper arranged to cooperate with the right needle, by an amount corresponding to the spacing between the left and right needles; and
- oscillating spreader mechanism, including a cover thread assist member that is connected to said oscillating spreader mechanism at a mid portion thereof, for assisting in casting said cover thread such that it is interwoven by the stitches formed by said two needles.
- 13. The invention as set forth in claim 12 wherein said cover thread assist member is constructed of a hardened wire that is connected to said spreader by silver solder.
- 14. The invention as set forth in claim 13 wherein said hardened wire has a diameter of about 0.05 inches.
- 15. The invention as set forth in claim 12 wherein said left and right row of stitches are each about 3/8 of an inch apart.
- 16. The invention as set forth in claim 12 wherein the point of the looper arranged to cooperate with the right needle is about 1/8 of an inch in the vertical direction further from the looper rocker axis than is the point of the loopers arranged to cooperate with the left needle.
- 17. The invention as set forth in claim 13 wherein the point of the looper arranged to cooperate with the right needle is about 1/8 of an inch in the vertical direction further from the looper rocker axis than is the point of the loopers arranged to cooperate with the left needle.
- 18. The invention as set forth in claim 16 wherein said cover thread assist member is constructed of a hardened wire that is connected to said spreader by silver solder.
- 19. The invention as set forth in claim 16 wherein said hardened wire has a diameter of about 0.05 inches.
- 20. The invention as set forth in claim 18 wherein said left and right row of stitches are each about 3/8 of an inch apart.
- 21. The invention as set forth in claim 1 wherein said cover thread assist member is constructed of a hardened wire that is adjustably connected to said spreader by screws.
- 22. The invention as set forth in claim 8 wherein said cover thread assist member is constructed of a hardened wire that is adjustably connected to said spreader by screws.
- 23. The invention as set forth in claim 12 wherein said cover thread assist member is constructed of a hardened wire that is adjustably connected to said spreader by screws.
- 24. A spreader mechanism for casting cover thread loops for use in a sewing machine that produces a stitch that includes a cover thread, said spreader mechanism comprising:
- an oscillating member having a generally arcuate shape;
- said oscillating member including a mid portion and a free end;
- a notch formed in said free end of said oscillating member; and
- a cover thread assist member connected to said mid portion of said oscillating member for cooperating with said oscillating member to form said cover thread loops.
- 25. The invention as set forth in claim 24 wherein said cover thread assist member is constructed of a hardened wire that is connected to said oscillating member by silver solder.
- 26. The invention as set forth in claim 24 wherein said cover thread assist member is constructed of a hardened wire that is adjustably connected to said oscillating member by screws.
CROSS-REFERENCE
The present application is a Continuation-in-Part application of Ser. No. 08/063,096 filed on May 17, 1993 that issued on Jan. 24, 1995 as U.S. Pat. No. 5,383,414, entitled APPARATUS FOR MAKING A THREE NEEDLE STITCH WITH COVER THREAD.
US Referenced Citations (5)
Foreign Referenced Citations (8)
Number |
Date |
Country |
510149 |
Oct 1930 |
DEX |
3346813C2 |
Jun 1984 |
DEX |
3639390C2 |
Feb 1987 |
DEX |
4000747C1 |
Jan 1990 |
DEX |
292872 |
Jun 1928 |
GBX |
294824 |
Oct 1928 |
GBX |
610365 |
Oct 1948 |
GBX |
709531 |
May 1954 |
GBX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
63096 |
May 1993 |
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