Method and apparatus for sewing mitered corners on a split needle bar sewing machine

• US 4,526,114 A
• Filed: 02/25/1983
• Issued: 07/02/1985
• Est. Priority Date: 02/25/1983
• Status: Expired due to Fees

• Current Assignee: Microdynamics Corporation (Microdynamics Group)
• Original Assignee: Microdynamics Corporation (Microdynamics Group)
• Inventors: Martell, Charles R., Leslie, Elmer N., Treadwell, Stephen S.
• Primary Examiner(s): Nerbun, Peter
• Application Number:
  US06/469,779
• Time in Patent Office: 858 Days
• Field of Search: 112/121.11, 112/121.12, 112/272, 112/275, 112/2, 112/315, 112/262.1, 112/163, 112/314
• US Class Current: 112/475.02
• CPC Class Codes: D05B 69/20 Control devices responsive to the number of stitches made
• CPC Class Codes: D05D 2205/085 combined with a display arrangement, e.g. touch sensitive control panel

Abstract

A semi-automatic split needle bar sewing machine (10) includes a sewing machine (12) which is driven by a motor (26) that drives a left needle (22) and a right needle (23). A presser foot (24) is operated by presser lift actuator (30). The needles (22) and (23) can activate in unison or independently by use of fall out actuators (41) and (43), respectively. A control chassis (50) includes a microprocessor controller (51) that is programmable through an input panel (44). An edge detector (40) detects the edge of the material to provide feedback for the microprocessor controller (51). The microprocessor controller (51) is operable to sew a decorative pattern with mitered corners by sensing the pivot point of the mitered corner and automatically disengaging one of the needles (22) or (23). The microprocessor controller (51) then continues single needle sewing around the apex of the mitered corner by counting a predetermined number of stitches and varying the length of the stitches such that the needle is in the correct position when the single needle sewing again arrives at the pivot point on the other side of the mitered corner. In this manner, it is not necessary for the operator to manually adjust the length of the stitches around the apex of the mitered corner.

Claims

1. A semi-automatic split needle bar sewing machine having multiple needles for sewing mitered corners on sewn products, comprising:

means for storing the parameters of a mitered corner such that the length of the outside seam between the inside corner and the apex of the mitered corner is predetermined;

means for calculating the number and the length of the stitches to be sewn in the outside seam of the mitered corner from the inside corner to the apex and from the apex to the inside corner such that the number of stitches on the outside seam on both sides of the mitered corner is equal;

means for determining the position of the inside corner of the mitered corner on the material relative to the material edge;

means for disabling one needle of the split bar needle on the inside seam of the mitered corner at the inside corner;

means for varying the length of the stitch being sewn; and

means for controlling and disabling means and said stitch varying means to automatically terminate double needle sewing at the inside corner and continue with single needle sewing of variable length stitches on the outside seam around the apex in accordance with the calculated values from said calculating means such that single needle sewing is terminated and double needle sewing begun after completion of the mitered corner.

2. The sewing machine of claim 1 wherein said determining means comprises at least one on/off sensor mounted ahead of the needles on the side from which the material is fed.

3. The sewing machine of claim 1 further comprising a material feed dog wherein said varying means comprises:

means for sensing the motor angle relative to the stitch displacement; and

means for controlling the material feed dog to control the amount of material fed under the stitching needle.

4. The sewing machine of claim 3 further comprising:

means for counting the number of stitches being sewn;

means for storing a predetermined number of stitches to be sewn for a given seam; and

said controlling means automatically terminating double needle sewing after said predetermined number of stitches is sewn thereby defining the position of the inside corner.

5. The sewing machine of claim 4 further comprising:

means for raising the presser foot on the sewing machine;

said controlling means automatically controlling said presser foot means to automatically terminate the sewing operation and raise the presser foot after a predetermined number of stitches are sewn between the pivot point and the apex of the mitered corner such that an operator can realign the material to complete the mitered corner.

6. A semi-automatic split needle bar sewing machine having multiple needles, a presser foot and a motor for sewing mitered corners in decorative and functional stitching on sewn products, comprising:

means for disengaging one of the needles of the split bar needle to discontinue double needle sewing on the inside seam at the inside corner of the mitered corner and allow only single needle sewing on the outside seam;

means for varying the length of stitches being sewn;

means for counting the number of stitches being sewn;

means for raising and lowering the pressure foot;

means for braking the motor and positioning the needle;

means for storing a profile for a plurality of mitered corners to define the relative position of the inside corner and the apex point of each mitered corner;

calculating means for calculating the length and number of stitches to be sewn in the outside seam of he mitered corner between the disengagement point at the inside corner and the apex of the mitered corner;

means for controlling the operation of the sewing machine to sew a mitered corner according to a selected one of said profiles by discontinuing double needle sewing at the inside corner of the mitered corner through control of said needle disengaging means and single needle sewing a number of stitches on the outside seam defined by said calculation means between the disengagement point and the apex on one side of the mitered corner and a number of stitches equal to the calculated number on said one side between the apex and the inside corner on the other side of the mitered corner with the stitch length varied to achieve the correct mitered corner in accordance with said calculation means;

said controlling means automatically braking the motor and positioning one of the needles down with the presser foot elevated at the apex of the corner; and

said controlling means automatically re-engaging the remaining needle at the inside corner on the other side of the mitered corner.

7. The apparatus of claim 6 wherein said means for controlling the length of stitches comprises:

means for sensing the angle of the motor in the sewing machine to determine the position of the motor with respect to the needle position and the feed dog position;

means for altering the amount of material fed by the feed dog; and

said controlling means controlling the operation of said altering means in response to said angle sensing means such that the amount of material being fed during the stitch can be altered to vary the length of the stitch.

8. The apparatus of claim 7 wherein said means for counting comprises a counter under the control of said means for controlling that senses said angle sensing means to determine the number of revolutions of the motor of the sewing machine.

9. The apparatus of claim 6 further comprising means for sensing a discontinuity in the material on the side from which the material is fed, said means for sensing mounted on the sewing machine such that said controller can determine the position of the inside corner with respect to said discontinuity according to said stored profile.

10. The apparatus of claim 9 wherein said sensing means comprises an on/off sensor.

11. The apparatus of claim 9 wherein said controlling means detects said discontinuity and varies the last double needle stitch before the inside corner.

12. The apparatus of claim 6 further comprising means for inputting said predetermined profile into said storage means.

13. The apparatus of claim 12 wherein said means for inputting is operable to modify said predetermined profile.

14. A method for sewing mitered corners on a split needle bar sewing machine, comprising:

automatically terminating double needle sewing by disengaging the inside needle at the inside corner of the mitered corner and allowing only single needle sewing on the outside seam;

calculating the length and number of stitches to be sewn on the outside seam between the disengagement point at the inside corner and the apex;

sewing the calculated number of stitches on the ouside seam to the apex of the mitered corner;

varying the length of the stitches in accordance with the calculated stitch length;

automatically terminating single needle sewing at the apex and allowing realignment of the material to sew the remaining side of the mitered corner;

sewing the calculated number of stitches upon resumption of single needle sewing to sew an identical number of stitches on the outside seam on the opposite side of the mitered corner from the apex to the point corresponding to the inside corner;

varying the length of the stitches in accordance with the calculated stitch length; and

automatically resuming double needle sewing by reengaging the inside needle when the calculated number of stitches on the outside seam has been sewn.

15. The method of claim 14 further comprising storing a profile that defines the relative position of the inside corner and the apex of the mitered corner in order to calculate the number of stitches to be sewn from the disengagement point to the apex and from the apex to the reengagement point during single needle sewing, the profile having the length of the stitches and the gauge between the needles stored therein.

16. The method of claim 14 wherein the steps of sewing the calculated number of stitches comprises counting the number of stitches between the inside corner and the apex by sensing the revolutions of the motor.

18. The method of claim 14 wherein the step of automatically terminating double needle sewing at the inside corner comprises:

detecting a discontinuity in the material from the feeding side of the presser foot to provide a reference point for determining the position of the inside corner relative to the material according to the profile;

counting a predetermined number of stitches from the point at which the discontinuity was detected; and

varying the length of the last stitch sewn prior to the inside corner.

19. The method of claim 14 wherein the step of automatically terminating double needle sewing comprises counting a predetermined number of stitches that defines the inside corner and terminating double needle sewing at the end of the last stitch.

17. The method of claim 17 further comprising modifying the predetermined profile to input the desired parameters for the mitered corner.

20. A method for sewing mitered corners on a split needle bar sewing machine for decorative and functional stitching of apparel products, comprising:

storing a profile containing the parameters of a desired mitered corner to be sewn with respect to the dimensions of the outside seam relative to the inside seam;

determining the relative position of the inside corner of the mitered corner with respect to the material edge;

automatically terminating double needle sewing at the inside corner by disengaging the inside needle and allowing only single needle sewing on the outside seam thereafter;

calculating the number of stitches and the length thereof for the outside seam between the disengagement point at the inside corner and the apex;

counting the number of stitches being sewn between the inside corner and the apex of the mitered corner on one side thereof;

varying the length of at least one of the stitches being sewn such that the overall length of the stitches is equal to the calculated value;

terminating single needle sewing at the apex and raising and lowering the presser foot to allow manual realignment of the material when the presser foot is raised;

counting the number of stitches sewn between the apex of the mitered corner and the inside corner on the other side of the mitered corner during single needle sewing from the apex to the inside corner;

varying the length of at least one of the stitches being sewn on the outside seam between the apex and the point at which the inside needle is proximate the inside corner on the other side of the mitered corner such that the outside needle is in the down position when the inside needle is proximate the inside corner wherein the correct mitered corner is achieved; and

automatically resuming double needle sewing at the inside corner by reengaging the inside needle.

22. The method of claim 20 wherein the step of determining the position of the inside corner comprises counting the number of stitches between initiation of the sewing operation and the inside corner as defined by the parameters stored in the profile.

23. The method of claim 20 wherein the step of determining the position of the inside corner comprises:

detecting the presence of a discontinuity in the material from the feeding side of the presser foot to provide a reference point for the needle with respect to the discontinuity; and

counting a predetermined number of stitches between the point of detection of the discontinuity and the inside corner, the terminating stitch having the length thereof varied.

24. The method of claim 23 wherein the discontinuity is the edge of the material.

25. The method of claim 20 wherein the step of automatically terminating double needle sewing comprises disabling the inside needle.

26. The method of claim 20 wherein the step of varying the length of the stitches between the inside corner and the apex during single needle sewing comprises varying the length of only the terminating stitch at the apex.

27. The method of claim 20 wherein the step of varying the length of the stitches being sewn during single needle sewing between the apex and the inside corner of the mitered corner comprises varying the length of the first stitch sewn from the apex and counting a predetermined number of equal length stitches such that the correct mitered corner is achieved.

28. The method of claim 20 wherein the step of counting stitches comprises sensing the angle of the motor to determine the occurrence of each revolution thereof.

29. The method of claim 20 further comprising initiating the sewing operation by pretacking.

21. A method for sewing mitered corners on a split needle bar sewing machine for decorative and functional stitching of sewn products, comprising:

individually inputting the parameters of the mitered corner on a keyboard for a desired mitered corner having a specified angle, needle gauge and stitch density between the seams;

determining the relative position of the inside corner of the mitered corner with respect to the material edge;

automatically terminating double needle sewing at the inside corner and allowing only single needle sewing thereafter;

counting the number of stitches being sewn between the inside corner and the apex of the mitered corner on one side thereof;

varying the length of at least one of the stitches being sewn such that that correct mitered corner is achieved;

terminating single needle sewing at the apex and raising and lowering the presser foot to allow manual realignment of the material;

counting the number of stitches sewn between the apex of the mitered corner and the inside corner on the other side of the mitered corner during single needle sewing from the apex to the inside corner;

varying the length of at least one of the stitches being sewn between the apex and the inside corner of the mitered corner on the other side thereof such that the correct mitered corner is achieved; and

automatically resuming double needle sewing at the inside corner.

30. A method for sewing mitered corners on a split needle bar sewing machine for decorative and functional stitching on sewn products, comprising:

inputting and storing parameters defining a profile for a desired mitered corner having an inside corner along the inner seam thereof and an apex on the outer seam thereof, the gauge of the needles, and the stitch density;

detecting the presence of a discontinuity on the material from the feeding side of the presser foot of the sewing machine to provide a reference point between the needle and the material;

determining the position of the inside corner with respect to the detected discontinuity according to the predetermined profile;

counting a predetermined number of stitches to the inside corner determined from a reference point stored in the predetermined profile, the last stitch of which is varied;

terminating double needle sewing at the inside corner by disabling the inner needle;

calculating the number of whole stitches having a length determined by the stored stitch density required to sew the seam from the disengagement point to the apex and the length of the last stitch such that the needle is in the down position at the apex;

counting the calculated number of whole stitches between the disengagement point and the apex of the mitered corner during single needle sewing on one side of the mitered corner and varying the length of the last stitch in accordance with the calculated length such that the correct mitered corner is achieved;

terminating single needle sewing at the apex of the mitered corner and raising and lowering the presser foot to allow manual realignment of the material for resuming single needle sewing;

counting a predetermined number of stitches between the apex and the point at which the inside needle is proximate the inside corner during single needle sewing on the other side of the mitered corner, the first stitch of which has the length thereof varied to equal the length of the last stitch on the first side and the remaining stitches sewn at full length such that and correct mitered corner is achieved; and

resuming double needle sewing by enabling the inside needle at the pivot point to end the pattern of the mitered corner.