JPH0347879B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a first holding means in the front side in the needle thread supply direction and a first holding means in the front side in the needle thread supply direction so as to clamp the needle thread so that the needle thread cannot pass therethrough by action and to release the needle thread so that the needle thread can pass through by non-action. and a feeding body that acts to increase and decrease the needle thread path between the second holding means and both holding means at times other than when the needle thread is picked up by the thread take-up,
Regarding a needle thread supply device for a sewing machine that allows a necessary length of needle thread to be paid out in advance for each stitch formation, in particular, a detection device that detects the rotation angle of a rotating body that rotates in conjunction with the delivery of needle thread, In a type of needle thread that detects the amount of thread let out each time one stitch is formed, and when the amount reaches a set amount, the first holding means is activated to prevent the needle thread from being let out until the next stitch is formed. The rotating body of the device is arranged to engage the needle thread between the first and second holding means, and a third holding means that operates at the same timing as the first holding means is installed between the rotating body and the feeding body. It is characterized by

Conventionally, in this type of device, only the first holding means is deactivated at times other than when the needle thread take-up is taken up by the thread take-up, and the needle thread is retracted from the bobbin between the first and second holding means by the action of the feeding body. When the detection device detects that a certain amount of thread has been drawn in, the first holding means is activated, the second holding means is deactivated, and the needle thread is supplied to the thread take-up at the time when the needle thread take-up is to be taken up by the thread take-up. It is consumed in the seams. However, if the rotating body of the detection device is placed outside between both holding means, the necessary amount of yarn is drawn between both holding means, and when the first holding means becomes active, the rotating body will over-rotate due to inertia. As a result, slack is created between the first holding means and the bobbin winder, and when the next time the feed-out body is fed out, the slack is completely drawn in between both holding means and the rotating body begins to rotate. It is not possible to accurately supply the required amount of thread for each formation, and if the rotating body is simply placed between both holding means, the rotating body will be swung under the influence of the thread tightening when the thread take-up is taken up by the needle thread take-up. In particular, when the sewing machine is operated at high speed, the next stitch begins to be fed out while the rotating body is being swung, so the amount of thread actually fed out and the detected amount of thread may differ from each other. There were drawbacks such as the inability to accurately supply the required amount of yarn for each formation.

This invention aims to eliminate the above-mentioned conventional drawbacks.

Embodiments of the present invention will be described below with reference to the drawings.

About the machine configuration Although the sewing machine is not shown in detail, the sewing machine has a main shaft that rotates in conjunction with a drive source, a needle bar that fixes the sewing machine needle with needle thread T and moves up and down in conjunction with the main shaft, and a bobbin spool as a needle thread supply source. The main shaft supports the needle thread T between the needle and the sewing machine needle, and is linked to the main shaft so as to repeatedly pick up the needle thread T.
It is also a known device that includes a balance 1 that reciprocates between two positions according to a timing curve (scale balance curve) with the top dead center of the needle bar at 0° as shown in FIG.

The holding means 2 and 3 are arranged on the needle thread path between the thread take-up thread take-up and the thread take-up lever 1 at a distance from each other in the direction of supplying the needle thread from the thread take-up thread take-up to the thread thread take-up thread take-up lever 1, and are connected to electromagnets ( SOL.1) 4 and electromagnet (SOL.2) 5, and a pair of retaining plates 2 that are joined by excitation and separated by de-excitation.
a, 2b and 3a, 3b, and when these holding plates are joined, the needle thread T is held immovably, and when they are separated, the needle thread T is movably released.

The guide plates 6, 7 are spaced apart from each other on both sides of the needle thread path between the two holding means 2, 3, and are fixedly arranged vertically.
Openings 6a and 7a are formed in the middle, respectively. A long groove 8a is formed in the upper part 8 of the sewing machine frame so as to face the gap between the guide plates 6 and 7.

The feeding body 9 includes a rocking body 11 whose middle part is rotatably supported on a shaft 10 fixed to the machine frame, and a rocking body 11.
A protrusion made of a rubber material is supported in the upper part so as to be rotatable about an axis 12 parallel to the axis 10, and is always fixed to the oscillator 11 by a coil spring 13 stretched between the oscillator 11 and the oscillator 11. openings 6a, 7 of both guide plates 6, 7;
Place related within a. As shown in FIG. 4, the feeding arm 14 has an upper end surface 14a tilted downward to the right to form a T-shape at the upper end, with the right corner serving as a thread hooking part 14b. Also, as shown in FIG. 3, the feeding body 14 bends and enlarges the needle thread path between the two holding means 2 and 3 at times other than when the needle thread T is picked up by the thread take-up 1, as shown in FIG. In order to prevent the needle thread path from being bent when the needle thread T is picked up by The elastic force of the coil spring 16 stretched between the machine frame and the machine frame causes pressure contact. The strength of the coil spring 13 is set to be weaker than the tension of the needle thread T when both the holding means 2 and 3 clamp the needle thread T while the needle thread path is being bent by the feeding body 9, and the coil spring 16 is coil spring 1
Set it stronger than 3.

The base tension 17 is disposed between the bobbin winding and the holding means 2 so as to always provide a constant passage resistance to the needle thread T. The rotating body 18 is rotatable in proportion to the amount of needle thread T being fed out from the bobbin winding when the needle thread T is fed out from the bobbin winding in conjunction with the operation of the feeding body 9.
Place it between 3.

The base tension 19 as a resistance imparting device is similar to the base tension 17.

The holding means 20 is disposed on the needle thread path from the rotating body 18 to the feeding body 9, and is joined to the electromagnet 21 in such a way that the needle thread T cannot pass through when the electromagnet 21 is energized, and when the electromagnet 21 is energized, the needle thread T cannot pass through. It consists of a pair of holding plates 20a and 20b separated from each other to allow passage.

Regarding the configuration of the electric circuit The feeding detection device 27 generates one pulse every time the rotating body 18 rotates by a certain angle. The position detection device 28 is arranged in relation to the main shaft, and includes a section A that detects the rotation angle of the main shaft at which the previous stitch knotting is completed and the balance 1 starts to descend and generates a position signal H; and a section B that detects the rotation angle range from just before the beginning of a period other than the needle thread pick-up period to just before the end of that period and generates a position signal H. The counter 29 is reset by a position signal from part A of the position detection device 28, and counts clock pulses from the feedout detection device 27. The setting device 30 consists of a digital switch that is set using a dial, and is set according to the length of needle thread T required to form one stitch (which varies depending on conditions such as the thickness of the fabric, the width of the needle, and the feed pitch). This is used to set the length of the needle thread T to be fed out, and a different digital code is generated corresponding to the set length. This digital code is related to the number of clock pulses from the payout detection device 27 which correspond to the rotation angle of the rotating body 18 which is proportional to the payout amount.

Comparison circuit 31 compares the output values of counter 29 and setting device 30, and generates an H match signal when both match. The operating circuits 32 and 33 are opened to excite the electromagnets 4, 5, and 21 upon receiving an H signal, and demagnetize the electromagnets 4, 5, and 21 upon receiving a low level (hereinafter referred to as L) signal. Close the circuit.
The flip-flop FF is reset by the position signal from the A section of the position detecting device 28 to set the Q terminal output to L, and the coincidence signal from the comparator circuit 31 sets the Q terminal output to L.
Inverts the terminal output from L to H.

Note that is an inverter.

Regarding the operation: When the sewing machine is driven, the thread take-up 1 rises to pick up the needle thread T between the holding means 3 and the needle or stitch, and then descends to relax it, and this process is repeated. In addition, during a period other than the above-mentioned time when the needle thread take-up is performed by the thread take-up, the swinging body 11 of the feeding body 9 is moved clockwise in FIG. Return clockwise.

When the rocking body 11 moves forward, the feeding arm 14 also moves together with the rocking body 11 due to the elastic force of the coil spring 13, bending the needle thread T between the openings 6a as shown in FIGS. 4 and 5b, The needle thread path between the holding means 2, 3 is increased. Note that during this period, FF is reset by the output of section A of the position detection device 28, and the output of section B is H, so one electromagnet 4, 21 is demagnetized and the other electromagnet 5 is energized. Therefore, the holding means 2, 20 on the supply source side are connected to the needle thread T.
is released, and the holding means 3 on the feeding side holds the needle thread T so that it cannot pass through, so that as the oscillating body (feeding body 9) 11 moves forward, the length of the needle thread corresponding to the increase in the above-mentioned path increases. T is unwound from the spool between the holding means 2 and 3.

When the needle thread T is paid out from the bobbin by the above action, the rotating body 18 rotates counterclockwise in FIG.
As a result, the feedout detection device 27 generates a number of clock pulses proportional to the rotation angle. These clock pulses are counted by a counter 29, and the counted value is inputted to one input section of a comparator circuit 31. When the count value of the counter 29 matches the output of the setting device 30, a matching signal of H is output from the comparison circuit 31, and the Q terminal output of the FF changes from L to H.
Since the electromagnets 4 and 21 are energized, the holding means 2 and 20 clamp the needle thread T so that it cannot pass through, thereby preventing the needle thread T from being paid out from the spool. At this time, the other holding means 3 continues to hold the needle thread T since the output of the position detection device 28 does not change. Therefore, after the needle thread T of the length set by the setting device 30 is let out from the bobbin winder, the needle thread T is held by both holding means 2, 3, and 20 so that it cannot pass through. If the oscillator 11 is in the middle of forward movement, the tension of the needle thread T between the holding means 2 and 3 causes the coil spring 13 to be
is stretched, the feeding arm 14 remains at that position, and the feeding of the needle thread T is completed.

Next, during the period from just before the time when the needle thread T is picked up by the balance 1 to just before the end of that time, the output of the B portion of the position detection device 28 becomes L, and the electromagnet 5
is demagnetized, so the holding means 3 releases the needle thread T. As a result, the needle thread fed out between both holding means is pulled out to the side of the thread take-up as the thread take-up 1 rises during this period, and the holding means 2 and the needle thread T between the stitches are tensioned. Eyes tighten and knot.

Thereafter, the above operation is repeated every time the balance 1 makes one reciprocation.

In this example, basic data regarding the length of needle thread required for tying each stitch is set by manual operation of a digital switch.
The pre-stored thread amount data is stored in the storage device based on the data detected by an appropriate detection means of the set position of the needle swing adjustment means and cloth feed adjustment means, or the data detected by the amount of motion of the needle swing mechanism or cloth feed mechanism. The data may be read out and used as the basic data for the feeding length, or data obtained by calculation based on the detected data may be input to the comparison circuit 31 as the basic data for the feeding length, or it may be stored in the storage device. In a type of sewing machine that operates the needle oscillation mechanism or cloth feed mechanism based on the stored data, the thread amount data stored in advance is simply read out, or the data calculated from the stored data is used to calculate the feed length. Comparison circuit 3 as basic data
1 may be input. In addition to data related to needle swing and fabric feed, we also collect detection data from a fabric thickness detection device that uses a potentiometer to detect changes in the position of the presser foot due to fabric thickness, as well as information on the type of fabric, such as yarn and weaving method. Correspondingly, the feeding amount may be set by combining data obtained through experiments in advance.

In this embodiment, the needle thread T is fed out from the bobbin between the holding means 2 and 3 by the feeding body 9 which reciprocates in conjunction with the cam body 15, and the holding means 2 is always inactive and the holding means 3 is in operation. , the holding means 2 in relation to the fact that the required amount of yarn is paid out (coincidence signal)
is activated, the holding means 3 is made inactive in relation to the position signal of the B part of the position detecting device 28, and the amount of needle thread fed out is reduced by the rise of the thread take-up during the period in which the holding means 3 is inactive. In this example, as shown in the first embodiment described in the specification and drawings of Japanese Patent Application No. 57-82712,
A rotating feeding body is arranged between both holding means in place of the feeding body 9 of the present application, and a comparison circuit 31
The control circuit may be associated with the control circuit in such a way that the holding means 2 are activated and the holding means 3 are deactivated at the same time in connection with a coincidence signal from the control circuit.

As described above, in the present invention, the rotating body of the detection device is arranged so as to engage the needle thread between the first and second holding means, and the rotating body and the feeding body are arranged at the same timing as the first holding means. Since the configuration includes a third holding means that operates,
Even when the needle thread is being picked up by the thread take-up, the influence of the thread tightening is blocked by the third holding means and is not transmitted to the rotating body, and even if the sewing machine is operated at high speed, the rotating body rotates only when the thread is being fed by the feeding body. , it is possible to always accurately supply the required amount of thread for each stitch formation, and there is an effect that a stitch with good thread tightness can be obtained.

In the above embodiment, the third holding means 20 which operates at the same timing as the first holding means 2 is provided independently, but the needle thread from the bobbin to the rotating body 18 and the feeding body 9 from the rotating body 18 The first holding means 2 may be arranged on both paths of the needle thread toward the needle thread, and may be used in combination with the third holding means.

[Brief explanation of drawings]

FIG. 1 is a needle perspective view of the main parts, FIG. 2 is a block diagram of the electric circuit, FIG. 3 is a time chart, and FIGS. 4 and 5 are action explanatory diagrams.

Claims (1)

[Scope of Claims] 1. Disposed on the needle thread path between the thread take-up and the needle thread supply source so as to be spaced apart from each other at the front and the front in the needle thread supply direction, so that the needle thread cannot pass through due to action and the needle thread cannot pass through due to non-action. After changing the needle thread path between the first and second holding means 2 and 3 that allow the needle thread to pass through and increasing the length of the path at a time other than when the needle thread is picked up by the thread take-up. In order to minimize the time it takes for the needle thread take-up to take up the maximum amount of needle thread, the thread take-up unit 9 operates in synchronization with the thread take-up, engages the needle thread between the first holding means and the thread take-up body, and rotates the needle thread by letting it out. Rotating body 18 to be moved
A feed-out detection device 27 that generates a thread amount signal corresponding to the rotation angle, and a position detection device that detects a specific rotation angle of the main shaft corresponding to a time other than the time when the needle thread is picked up by the thread take-up and generates a position signal. 28, and a setting device 30 capable of generating a setting signal corresponding to the length of needle thread required to form one stitch in response to different sewing conditions, and a thread amount detection signal and a setting signal are compared to determine whether they match. a comparator circuit which generates a coincidence signal when the first holding means is always inactive, activated in relation to the coincidence signal and deactivated by a subsequent position signal, and the second holding means is always activated so that the coincidence occurs. a control circuit that is inactivated by a signal or a subsequent position signal and then activated after the end of the needle thread take-up period by the thread take-up; In the needle thread paying-out device, a third holding means 20 is provided between the feeding-out detection device and the feeding body, and the third holding means 20 is provided between the feeding-out detection device and the feeding body, and the third holding means 20 is provided between the feeding-out detection device and the feeding body, and the third holding means 20 makes it impossible to pass the needle thread through action and allows it to pass through the needle thread when inactive. A needle thread supply device for a sewing machine, characterized in that the operation of the first holding means is controlled via a control circuit at the same timing as the first holding means.