Control system for sewing machine

In a semiautomatic sewing system including a sewing machine with a reciprocable needle for stitching material advanced in a feed direction and controls for operating said sewing machine, with means for counting stitches being sewn, and with sensors for detecting manipulation of the sewing machine controls, the improvement which comprises:

• means mounted in spaced relationship with said needle for detecting the material periphery following a seam;
• and
• a microprocessor controller with plural operational modes coupled to said sewing machine controls and responsive to said stitch counting means and said material detection means, said microprocessor controller in one mode being operable to record the operational sequence of said sewing machine controls as a function of stitch count and to compute the terminal number of stitches for each seam between detection of the material periphery and the end point of said seam;
• said microprocessor controller in another mode being responsive to said material detection means to operate said sewing machine controls and halt said sewing machine said terminal number of stitches after detection of the material periphery following the seam.

A semiautomatic sewing system, comprising:

• a sewing machine;
• said sewing machine including a reciprocable needle for stitching a seam in material advanced along a feed direction, and controls for operating said sewing machine;
• auxiliary means for performing a predetermined function associated with operation of said sewing machine;
• means for counting stitches being sewn by said sewing machine;
• means mounted in spaced relationship with said needle for detecting the material periphery following a seam;
• a microprocessor controller responsive to said stitch counting means and said material detection means, and being coupled to said sewing machine controls and said auxiliary means;
• said microprocessor controller having plural operational modes, and being operable in one mode to record the operational sequence of said sewing machine controls as a function of stitch count and to compute the terminal number of stitches for each seam between detection of the material periphery and the end point of said seam;
• said microprocessor controller in said one mode being further operable to record the operational sequence of said auxiliary means as a function of stitch count;
• said microprocessor controller in another mode being responsive to said material detection means to operate said sewing machine controls and halt said sewing machine said terminal number of stitches after detection of the material periphery following the seam;
• and
• said microprocessor controller in said other mode further being operable to control said auxiliary means.

A method of controlling seam lengths and end points sewn in material with a sewing machine, comprising the steps of:

• providing a sensor for detecting the presence of material a predetermined distance ahead of the needle of said sewing machine;
• storing a stitch count value X corresponding to a point near the end of each seam where a sensor status change should occur;
• storing a stitch count value Y corresponding to the total number of stitches in each seam, at least a portion of said stitch count value Y being manually entered and stored by actuation of a one-stitch switch;
• positioning the material for sewing under the needle of said sewing machine;
• starting the sewing machine;
• accelerating the sewing machine and operating the sewing machine at substantially constant speed over that portion of the seam where the stitch count value Y was manually incremented before stopping;
• counting the number of stitches sewn in each seam beginning with the first stitch in the seam;
• controlling auxiliary devices associated with the sewing machine as a function of stitch count;
• comparing the stitch count with the stored stitch count values;
• initiating countdown of Y-X stitches responsive to a status change in said sensor;
• and
• stopping the sewing machine upon completion of the countdown of Y-X stitches to complete each seam.

A method of controlling seam lengths and end points sewn in material with a sewing machine, comprising the steps of:

• manually operating said sewing machine and each auxiliary device to sew seams on a similar piece of material;
• sensing manual operation of auxiliary devices associated with the sewing machine to generate control input signals;
• storing the control input signals of said auxiliary devices as a function of stitch count;
• providing a sensor for detecting the presence of material a predetermined distance ahead of the needle of said sewing machine;
• storing a stitch count value X corresponding to a point near the end of each seam where a sensor status change should occur;
• storing a stitch count value Y corresponding to the total number of stitches in each seam;
• positioning the material for sewing under the needle of said sewing machine;
• starting the sewing machine;
• counting the number of stitches sewn in each seam beginning with the first stitch in the seam;
• controlling said auxiliary devices as a function of stitch count by generation of control output signals;
• comparing the stitch count with the stored stitch count values;
• initiating countdown of Y-X stitches responsive to a status change in said sensor;
• stopping the sewing machine upon completion of the countdown of Y-X stitches to complete each seam;
• and
• generating subsequent control output signals for said auxiliary devices responsive to stitch count.

A method of performing a sewing operation involving a series of seams with a sewing machine having a reciprocable needle for stitching material advanced in a feed direction and controls for operating the sewing machine, the method comprising the steps of:

• counting the number of stitches being sewn by the sewing machine;
• detecting an edge of material following a seam;
• storing a plurality of stitch counts corresponding to different seams in the sewing operation to be performed;
• generating first and second output signals in response to the detection of said material edge, said counted number of stitches and said stored plurality of stitch counts;
• stopping said sewing machine in response to said first output signal a preprogrammed number of stitches after detection of the material edge, said preprogrammed number of stitches corresponding to the stitch count stored for the particular seam being sewn;
• and
• performing control of the sewing machine in response to said second output signal.