Thread supply device used in a sewing apparatus with a plurality of needles

A thread supply device used in a sewing apparatus having a plurality of needles and a looper mechanism, in which needle threads guided to the needles and a looper thread guided to the looper mechanism are cut by a thread cutting unit at a cutting position, which is off a thread supply path, after a sewing operation is finished but before the following sewing operation starts, the thread supply device comprising:

• a supply mechanism for forcibly supplying a plurality of needle threads, said supply mechanism including at least a pair of rollers for holding the needle threads and a motor for driving the rollers to feed the needle threads at a circumferential speed of the rollers;
• a stopping mechanism for stopping the needle threads from being supplied, said stopping mechanism including thread holding units respectively provided for the needle threads in an upstream portion from said supply mechanism in the thread supply path, each thread holding unit having an electromagnetic solenoid and a holding member for holding the thread between the electromagnetic solenoid and the holding member by use of a magnetic force generated by electrifying the electromagnetic solenoid;
• memory means for storing a predetermined length of each needle thread, which is required for a cutting operation;
• control means for reading out the predetermined length of each needle thread from said memory means and controlling said supply mechanism and said stopping mechanism so that each needle thread is supplied in a corresponding predetermined length;
• and
• wherein the motor has a rotary encoder for detecting a rotating amount of the motor and outputting the rotating amount as pulses, a number of which indicates a corresponding predetermined length stored in said memory means.

A thread supply device used in a sewing apparatus having a plurality of needles and a looper mechanism, in which needle threads guided to the needles and a looper thread guided to the looper mechanism are cut by a thread cutting unit at a cutting position, which is off a thread supply path, after a sewing operation is finished but before the following sewing operation starts, the thread supply device comprising:

• a supply mechanism for forcibly supplying a plurality of needle threads and a looper thread;
• a stopping mechanism for stopping the threads from being supplied by holding the threads;
• memory means for storing a first predetermined length of each needle and looper thread individually, which is required for a cutting operation, and a second predetermined length of the looper thread, which is required to prevent the looper thread from coming off from the looper mechanism when the following sewing operation starts;
• and
• control means for reading out the first predetermined length of each thread and the second predetermined length from said memory means, for controlling said supply mechanism and said stopping mechanism so that each thread is supplied in the first predetermined length, for controlling the thread cutting unit to cut the threads, and then for controlling said supply mechanism and said stopping mechanism so that the looper thread is supplied in the second predetermined length.

A thread supply device used in a sewing apparatus having a plurality of needles and a looper mechanism, in which needle threads guided to the needles and a looper thread guided to the looper mechanism are cut by a thread cutting unit at a cutting position, which is off a thread supply path, after a sewing operation is finished but before the following sewing operation starts, the thread supply device comprising:

• a supply mechanism for forcibly supplying a plurality of needle threads and a looper thread, said supply mechanism including at least a pair of rollers for holding the needle threads and a motor for driving the rollers to feed the needle threads at a circumferential speed of the rollers;
• a stopping mechanism for stopping the threads from being supplied, said stopping mechanism including thread holding units respectively provided for the needle threads in an upstream portion from said supply mechanism in the thread supply path, each thread holding unit having an electromagnetic solenoid and a holding member for holding the thread between the electromagnetic solenoid and the holding member by use of a magnetic force generated by electrifying the electromagnetic solenoid;
• memory means for storing a first predetermined length of each thread, which is required for a cutting operation, and a second predetermined length of the looper thread, which is required to prevent the looper thread from coming off from the looper mechanism when the following sewing operation starts;
• control means for reading out the first predetermined length of each thread and the second predetermined length from said memory means, for controlling said supply mechanism and said stopping mechanism so that each thread is supplied in the first predetermined length, for controlling the thread cutting unit to cut the threads, and then for controlling said supply mechanism and said stopping mechanism so that the looper thread is supplied in the second predetermined length;
• and
• wherein the motor has a rotary encoder for detecting a rotating amount of the motor and outputting the rotating amount as pulses, a number of which indicates a corresponding predetermined length stored in said memory means.

A thread supply device used in a sewing apparatus having a plurality of needles and a looper mechanism, in which needle threads guided to the needles and a looper thread guided to the looper mechanism are cut by a thread cutting unit at a cutting position which is off a thread supply path after a sewing operation is finished but before the following sewing operation starts, the thread supply device comprising:

• a supply mechanism for forcibly supplying a plurality of needle threads and looper thread, said supply mechanism comprising at least a pair of rollers for holding the thread and a motor for driving the rollers to feed the thread at a circumferential speed of the rollers, the motor having a rotary encoder for detecting a rotating amount of the motor and outputting the rotating amount as pulses;
• a stopping mechanism for stopping the threads from being supplied by holding the threads, said stopping mechanism comprising thread holding units respectively provided for the threads in an upstream portion from said supply mechanism in the thread supply path, each thread holding unit comprising an electromagnetic solenoid and a holding member for holding the thread between the electromagnetic solenoid and the holding member by use of a magnetic force generated by electrifying the electromagnetic solenoid;
• memory means for storing a first predetermined length of each thread, which is required for a cutting operation, and a second predetermined length of the looper thread, which is required to prevent the looper thread from coming off from the looper mechanism when the following sewing operation starts, the first and the second predetermined lengths each being defined by a number of pulses, the first predetermined length of each thread being different from one another;
• detecting means for detecting that the sewing operation is finished;
• a counter for counting the number of the pulses sent from the rotary encoder or the motor;
• and
• control means comprising a first control section for controlling the thread holding units to release the threads when said detecting means detects that the sewing operation is finished;
• a second control section for, when the number counted by said counter corresponds with the first predetermined length of each thread, controlling the corresponding thread holding unit to hold the thread;
• a third control section for, when all the thread holding units hold the threads, controlling the thread cutting unit to cut the threads;
• and a fourth control section for, after the threads are cut, controlling the thread holding unit which is holding the looper thread to feed the looper thread in the second predetermined length.