Method and apparatus for automatic adjustment of thread tension

An apparatus for stitching fabric while automatically controlling tension applied to thread used in the stitching, comprising:

• first means for supplying information related to actual length of thread used for at least one stitch;
• a tensioning assembly for tensioning the thread that is used in stitching the fabric with the at least one stitch;
• and
• second means responsive to at least said first means for enabling stitching and for controlling said tensioning assembly, said second means including a plurality of processors and a first head stitching machine, said plurality of processors including a server processor and a first head control processor and in which said first head control processor operates with said first head stitching machine and inputs data to said server for use by said server processor in controlling stitching by said first head stitching machine;
• wherein said second means determines a value related to said desired thread length using a first factor related to desired thread length, with said value related to said desired thread length being dependent on at least one predetermined factor different from said first factor.

An apparatus for stitching fabric while automatically controlling tension applied to thread used in the stitching, comprising:

• first means for supplying information related to actual length of thread used for at least one stitch;
• second means for providing a first factor related to desired thread length, said second means including first display means for indicating a relationship between a top thread length and a bobbin thread length of at least one stitch;
• a tensioning assembly for tensioning the thread that is used in stitching the fabric with the at least one stitch;
• and
• third means responsive to said first means and said second means for enabling stitching and for controlling said tensioning assembly;
• wherein said third means determines a value related to said desired thread length, with said value related to said desired thread length being dependent on at least one predetermined factor different from said first factor.

A method for stitching at least a first stitch using thread, comprising:

• determining at least a first control output by a stitching control system using at least a desired length of said first stitch;
• applying said first control output to a tensioning assembly for adjusting tension of the thread to a first tension;
• stitching a first portion of said first stitch using said first tension;
• adjusting tension of the thread to a second tension, different from said first tension, while said first stitch is being stitched;
• and
• stitching a second portion of said first stitch using said second tension.

A method for stitching a pattern having at least a first stitch and a second stitch using thread, comprising:

• obtaining a first magnitude of a first factor related to each of the first and second stitches used by a stitching control system;
• determining a first control output by said stitching control system using at least said first magnitude of said first factor, said step of determining said first control output including providing to said stitching control system a value related to stitch speed;
• applying said first control output to a tensioning assembly for adjusting tension of the thread to a first tension;
• stitching the first stitch of the pattern having a first desired thread length using said first tension;
• determining a second control output using at least said first magnitude of said first factor, wherein said second control output is different from said first control output;
• applying said second control output to said tensioning assembly for adjusting the tension of the thread to a second tension;
• and
• stitching the second stitch of the pattern having a second desired thread length and in which the first and second desired thread lengths are different.

A method for stitching a pattern having at least a first stitch and a second stitch using thread, comprising:

• obtaining a first magnitude of a first factor related to each of said first and second stitches for use by a stitching control system, said step of obtaining said first magnitude of said first factor including inputting said first magnitude using operator input means;
• determining a first control output by said stitching control system using at least said first magnitude of said first factor;
• applying said first control output to a tensioning assembly for adjusting tension of the thread to a first tension;
• stitching said first stitch of the pattern having a first desired thread length using said first tension;
• determining a second control output using at least said first magnitude of said first factor, wherein said second control output is different from said first control output;
• applying said second control output to said tensioning assembly for adjusting tension of the thread to a second tension;
• and
• stitching said second stitch of the pattern having a second desired thread length and in which said first and second desired thread lengths are different.

An apparatus for stitching fabric while automatically controlling tension applied to thread used in the stitching, comprising:

• an operator input means including at least a first display means for indicating a relationship between top thread length and bobbin thread length;
• a tensioning assembly for tensioning the thread that is used in stitching the fabric;
• and
• a stitching control system responsive to said operator input device for enabling stitching and for controlling said tensioning assembly.

A method for stitching a pattern having a plurality of stitches, with each stitch including a top thread length and a bobbin thread length, comprising:

• providing a stitching control system;
• providing operator input means;
• inputting a first factor related to top thread length and bobbin thread length to said stitching control system using said operator input means;
• obtaining a ratio between said top thread length and said bobbin thread length by adjusting tension applied to the thread using a control output applied to a tensioning assembly;
• and
• stitching at least one stitch of the pattern.

A method for controlling thread tension when more than one thread is being stitched at one time, comprising:

• providing a plurality of stitching machines together having a number of heads, including a first head, each head for stitching thread in fabric;
• determining a desired thread tension based on stitching fabric by said first head;
• inputting information related to said desired thread tension based on said determining step;
• applying automatically said information to each of said number of heads after said inputting step;
• and
• stitching thread for each of said heads having said desired thread tension.

A method for stitching a pattern having at least a first stitch and a second stitch using thread, comprising:

• determining a first control output using a first stitch length modifier that has a value depending on a length of a first stitch;
• controlling a tensioning assembly using said first control output to provide a first tension associated with said first stitch, said controlling step including compensating for less tension in said first stitch due to said length thereof;
• stitching said first stitch having said first length;
• determining a second control output using a second stitch length modifier that has a value depending on a second length of a second stitch;
• controlling said tensioning assembly using said second control output to provide a second tension associated with said second stitch, said controlling step including compensating for increased tension in said second stitch due to said length thereof and with said second length of said second stitch being less than said first length of said first stitch;
• and
• stitching said second stitch having said second length after stitching said first stitch.