JP2008036218A - sewing machine - Google Patents

Abstract

A sewing machine includes a needle drive mechanism that drives a sewing needle up and down by a sewing machine motor, and a cloth that moves forward and backward in synchronization with the vertical movement of the sewing needle. A lower looper drive mechanism 20 having a lower looper 21 having an extending portion 21a inserted into the needle thread loop on the lower side, and an upper looper 11 for inserting the upper looper thread into the loop of the lower looper thread T are provided. The upper looper driving mechanism 10, the threading device 100 for threading the thread through the thread hole 21b of the lower looper 21, the thread tension device 30 for applying tension to the needle thread, the pressing mechanism (not shown) for pressing the fabric, and the above-described parts And a control unit 50 for controlling the driving of the motor. Then, by setting the upper end portion of the thread guide lever 121 of the threading device 100 to be a hook-shaped portion 121d that is bent in a substantially L shape, the needle thread can be easily approached when changing the thread.
[Selection] Figure 3

Description

  The present invention relates to a sewing machine, and more particularly, to a sewing machine including a threading device that passes a thread through a looper that forms a seam in cooperation with a sewing needle.

2. Description of the Related Art Conventionally, for example, in an edge overlock sewing machine, a double chain stitch sewing machine, or the like, a sewing machine including a threading device that passes a thread through a looper using pressurized air is known (for example, Patent Documents). 1). As shown in FIG. 12, the threading device in such a sewing machine has a thread guide lever 220 (see FIG. 14) whose one end moves in the vicinity of the swinging lower looper 210 substantially along the movement locus of the lower looper 210. And a yarn path pipe 221 supported by the yarn guide lever 220.
When a thread (hereinafter referred to as a lower looper thread) is passed through the lower looper 210, the thread discharge port 221a at one end of the thread path pipe 221 is aligned with the thread hole 210a of the lower looper 210, and then the thread path pipe The lower looper thread is inserted into the thread hole of the lower looper 210 by blowing pressurized air to the thread insertion port 221 b at the other end of the cover 221.
JP 2005-318932 A

  By the way, in the edge overlock sewing machine or the double chain stitch sewing machine, the lower looper thread may be changed to a colored thread or the like during the sewing. However, in the sewing machine having the threading device disclosed in Patent Document 1, when the lower looper thread is changed while the needle thread is stretched over the lower looper 210, the lower looper 210 is caught. It cannot be said that the loop of the needle thread (needle thread) does not pass through the gap between the thread guide member 220 and the lower looper 210 as shown in FIG. There has been a problem that it cannot be said that a yarn feed defect does not occur when the looper 210 is moved toward the tip side. Further, when the needle thread is sandwiched between the thread guide member 220 and the lower looper 210, the order of thread change occurs, and the state where the needle thread is applied to the lower looper 210 by cutting the needle thread once is released. There is a problem that the work is complicated.

  An object of the present invention is to facilitate the replacement of the looper yarn.

  In order to solve the above-mentioned problem, the invention according to claim 1 is inserted into a needle thread loop by a needle driving mechanism that drives a needle up and down by a sewing machine motor and by moving back and forth in synchronization with the vertical movement of the needle. A looper driving mechanism having a looper having an extension part with a thread hole formed at the tip, a yarn path pipe having one end as a thread insertion port, the other end as a thread discharge port, and a thread path through which a thread can be inserted And a yarn path pipe movement that moves the thread path pipe so that the thread discharge port is movable between a threading position that matches the thread hole of the looper and a retracted position that is away from the threading position. Means, an air blowing means that is disposed opposite to the yarn insertion port, and blows air to the yarn insertion port, and an air supply unit that supplies air to the air blowing unit, and the yarn path pipe includes the yarn passage pipe. Movably provided with the other end of the canal A thread-feeding portion that moves along the extending portion of the paper, and the needle thread that is passed over the looper when the yarn path moving means moves from the retracted position to the threading position. The sewing machine is characterized by being brought close to the tip side of the sewing machine.

  According to a second aspect of the present invention, in the first aspect of the present invention, the yarn gathering portion has a hook-shaped portion bent in a substantially L shape so as to pass above the looper. .

  The invention described in claim 3 is the invention described in claim 1 or 2, further comprising a thread tension device that applies tension to the needle thread, and the thread tension device is configured such that the yarn path pipe is moved from the retracted position. A tension release means is provided for releasing the tension of the needle thread in conjunction with the thread shifting portion when moved to the threading position.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the tension release means includes an actuator that releases the tension of the thread tension device, a detection means that detects movement of the yarn feeder, and the detection means. Control means for driving the actuator based on the detection of the tension to release the tension of the thread tension device.

  According to the first aspect of the present invention, when the yarn path tube is moved from the retracted position to the threading position by the yarn path tube moving means, the yarn guide portion is moved along the extending portion of the looper. That is, when the yarn path pipe is moved from the retracted position to the threading position, the thread gathering portion crosses the needle thread path of the needle thread that is stretched over the looper, so that the needle thread stretched over the looper is It can be brought close to the tip of the looper. Therefore, for example, when changing the thread of the looper, it is not necessary to cut the needle thread, and the thread of the looper can be changed easily. In addition, since it is not necessary to cut the needle thread or remove it from the looper when changing the thread, for example, even when sewing with a plurality of needles, the needle threads individually passed through each needle are arranged. The loop of the looper can be easily changed without considering the order.

  According to the invention described in claim 2, the invention according to claim 1 has a simple configuration by the yarn feeder having a hook-like portion bent in a substantially L shape so as to pass above the looper. The same effect can be obtained.

  According to the invention described in claim 3, in addition to obtaining the same effect as that of the invention described in claim 1 or 2, in particular, the yarn path pipe is moved from the retracted position to the threading position by the thread path moving means. When moved, the tension of the needle thread is released by the thread tension device in conjunction with the thread shifting section. Therefore, the needle thread can be pulled out freely when the yarn path pipe is moved from the retracted position to the threading position. That is, when changing the looper thread, the needle thread can be smoothly moved toward the tip side of the looper, so that the looper thread can be easily changed.

  According to the fourth aspect of the present invention, the same effect as that of the third aspect of the present invention can be obtained. In particular, when the movement of the yarn moving portion is detected by the detecting means, the control is performed based on the detection signal. The actuator of the thread tension device is driven by the means, and the tension of the needle thread is released. That is, the tension of the needle thread can be automatically released when the thread path pipe is moved from the retracted position to the threading position by the thread path moving means, so that the needle thread can be freely released when the thread is moved. Can be pulled out. Thereby, the yarn pulling of the looper can be easily performed.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS. In the present embodiment, an edge sewing machine will be described as an example of the sewing machine. The edge sewing machine includes a sewing needle that moves up and down, a lower looper 21 that allows the lower looper thread T to pass through a loop of the sewing thread that is passed through the sewing needle below the cloth that is to be sewn, and the lower looper thread T. The sewing machine includes an upper looper 11 through which an upper looper thread is inserted into the loop. The sewing machine performs edge stitching on the fabric by sequentially interlacing the thread with the sewing needle, the lower looper 21 and the upper looper 11.
In the following description, the vertical vertical direction is the Z-axis direction, and the longitudinal direction (left-right direction) of the arm portion of the sewing machine 1 in a state of being installed on a horizontal plane is the Y-axis direction, which is parallel to the plate surface of a needle plate (not shown). The longitudinal direction perpendicular to the Y-axis direction is taken as the X-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are assumed to be orthogonal to each other.

(Main components of the sewing machine)
FIG. 1 is a side view showing an overall configuration of a sewing machine 1 according to an embodiment of the present invention.
As shown in FIG. 1, the edge sewing machine (hereinafter simply referred to as a sewing machine 1) includes a needle driving mechanism (not shown) that drives a sewing needle (needle) up and down by a sewing machine motor 5 (see FIG. 10), and a sewing machine. A lower looper 21 having an extending portion 21a inserted into a loop of needle threads T1, T2 (see FIGS. 2 and 3) on the lower side of the cloth to be sewn by moving back and forth in synchronization with the vertical movement of the needle. A lower looper drive mechanism 20 provided with an upper looper drive mechanism 10 provided with an upper looper 11 for inserting the upper looper thread into the loop of the lower looper thread T, and a thread for passing the thread through the thread hole 21b of the lower looper 21. The threading device 100 includes a thread tension device 30 (see FIG. 9) that applies tension to the needle thread, a pressing mechanism (not shown) that presses the fabric, and a control unit 50 that controls the driving of the above-described units. Hereinafter, each part will be described in detail.

(Needle drive mechanism)
A needle drive mechanism (not shown) includes an upper shaft as a main shaft of a sewing machine that is rotated by a sewing machine motor 5, and a known transmission mechanism that converts the rotational movement of the upper shaft into a vertical movement by a rotary weight and a crank rod and transmits the movement to the needle bar 2. It has. Two sewing needles are held at the lower end of the needle bar 2, and the needle thread T1 is inserted into the sewing needle on the left side (left side in FIGS. 1 to 3) when viewed from the operator, The needle thread T2 is inserted. When the upper shaft is rotated by driving the sewing machine motor 5, the needle bar 2 is moved up and down through the transmission mechanism, and the needle bar 2 and the sewing needle reciprocate up and down.

(Upper looper drive mechanism)
The upper looper driving mechanism 10 includes an upper looper 11, an upper looper holding body 12 that holds the upper looper 11, and a support member that supports the upper looper holding body 12 so as to be capable of linearly moving and rotating around two axes. 13 and an operating mechanism 14 for reciprocating a connection point between the upper looper holding body 12 and two positions. The upper looper holding body 12 is a round bar, and holds the upper looper 11 at one end (upper end in FIG. 1). The upper looper 11 passes the rear of the movement locus of the lower looper 21, which will be described later, and inserts the upper looper thread, and moves the tip of the upper looper thread to the needle drop position of the sewing needle to sew the loop on the upper looper thread. The needle and needle thread T1, T2 are inserted.

(Lower looper drive mechanism)
The lower looper drive mechanism 20 is disposed below the throat plate (not shown), and is branched from a lower looper drive shaft 22 rotatably supported by the sewing machine frame M along the front-rear direction, and from a sewing machine main shaft (not shown). A transmission mechanism (not shown) that converts the rotational driving force into a reciprocating rotational driving force and applies it to the lower looper driving shaft 22, and a lower looper holding arm 23 that is fixedly mounted on the tip of the lower looper driving shaft 22 and swings. And a lower looper 21 held at the rocking end.
The lower looper drive shaft 22 swings the lower looper holding arm 23 by reciprocatingly rotating in synchronization with the sewing machine main shaft. As a result, the lower looper 21 moves so as to pass near the movement locus of the sewing needle on the lower side of the needle plate and behind the sewing needle. The lower looper 21 captures the loop of the needle threads T1 and T2 inserted through the lowered sewing needle, and inserts the loop of the lower thread (hereinafter referred to as the lower looper thread T) into the loop.

  Further, as shown in FIGS. 7 and 8, a thread hole 21b through which the thread discharged from the thread discharge port 112 of the thread passage pipe 110, which will be described later, is formed at the sword tip of the lower looper 21, that is, the tip of the extension part 21a. Has been. Further, a looper groove 21c is formed from the yarn hole 21b toward a portion facing the retracted position of the yarn discharge port 112. The looper groove 21c is used to prevent the yarn discharged from the yarn discharge port 112 from being pinched between the lower looper 21 and a yarn guide lever 121 described later and preventing the yarn guide lever 121 from rotating. It is.

(Thread tension device)
The thread tension device 30 includes a pair of thread tension plates 31 and 32 that are provided in the arm portion of the sewing machine frame M and apply tension to the needle threads T1 and T2 by sandwiching the needle threads T1 and T2, and one thread. A thread tension solenoid 34 as an actuator in this embodiment is provided that is connected to the tension tray 32 and moves the thread tension tray 32 relative to and away from the other thread tension tray 31.
The yarn tension solenoid 34 is connected to a control unit 50 described later, and is driven according to a control signal from the control unit 50. In this embodiment, the yarn tension solenoid 34 is driven by the control unit 50 based on an output signal from a detection sensor 130 described later, whereby the yarn path pipe 110 is moved from the retracted position to the threading position. At the same time, it functions as a tension releasing means for releasing the tension of the needle threads T1, T2 in conjunction with a hook-shaped part 121d, which will be described later, which is a yarn gathering part.

(Threading device)
Next, the threading device 100 in this embodiment will be described in detail.
The threading device 100 is for passing the lower looper thread T guided from the thread groove 6 formed in the sewing machine frame M through the thread hole 21b of the lower looper 21, and is provided below the needle bar 2. Yes.
As shown in FIG. 1, the threading device 100 has a thread passage tube 110 having a thread insertion port 111 at one end and a thread discharge port 112 at the other end and a thread path through which the thread can be inserted, The thread passage pipe is configured such that the outlet 112 can move between a threading position (see FIG. 3) that matches the thread hole 21b of the lower looper 21 and a retracted position (see FIG. 2) that is away from the threading position. 110, a moving mechanism 120 as a yarn path moving means, a detection sensor 130 for detecting that the moving mechanism 120 has moved from the retracted position, and a yarn insertion port 111. An air blowing unit 140 as air blowing means for blowing air and an air pump 150 as air supply means for supplying air to the air blowing unit 140 are provided.

(Thread guide means)
As shown in FIGS. 1 to 3, the yarn path pipe 110 is provided in parallel to a plane on which the lower looper 21 provided below the needle bar 2 swings. The yarn path pipe 110 is a tubular member that is curved in two places and is formed in a substantially U shape in a side view. As shown in FIG. 4, the yarn path pipe 110 functions as a thread insertion port 111 into which one end inserts a thread, and the diameter of the thread insertion port 111 is increased toward the end side. This is to facilitate the insertion of the lower looper thread T. Further, as shown in FIG. 5, the yarn path pipe 110 functions as a yarn discharge port 112 through which the other end discharges the yarn, and the end of the yarn discharge port 112 is bent at a substantially right angle. That is, the yarn path pipe 110 functions as a yarn guiding means for guiding the lower looper yarn T to the yarn hole 21 a of the lower looper 21.
The yarn path pipe 110 has a threading position (position shown in FIG. 3) where the yarn discharge port 112 matches the thread hole 21b of the lower looper 21, and a retracted position away from the threading position (position shown in FIG. 2). Are connected to a moving mechanism 120 that moves the yarn path pipe 110 so as to be movable between the two.

(Thread passage moving means)
The moving mechanism 120 supports the yarn path tube 110, and a thread guide lever 121 whose one end reciprocates between a threading position and a retracted position by swinging, and a thread that rotatably supports the thread guide lever 121. Switching the guide lever base 122, one end of the thread guide lever 121 and the thread guide lever base 122, and switching the position of the thread discharge port 112 between the threading position and the retracted position by swinging the thread guide lever 121 Lever 123.

The yarn guide lever 121 is formed from a long plate material, and is formed such that one end and the other end are curved in opposite directions. The thread guide lever 121 has a long hole 121a substantially at the center, and is locked to the thread guide lever base 122 through this long hole 121a. One end of the yarn guide lever 121 (the upper end in FIGS. 1 to 3) is attached so that one end of the yarn path pipe 110 penetrates from the front surface side to the back surface side. Function. Further, in the vicinity of the center portion of the yarn guide lever 121, the vicinity of the yarn insertion port 111 of the yarn path pipe 110 is bonded by an adhesive or solder. Further, a connecting hole 121 b for connecting to the switching lever 123 is formed at the other end of the yarn guide lever 121.
Furthermore, at one end (upper end) of the yarn guide lever 121 in the present embodiment, as shown in FIG. 5, a hook-like portion 121d is formed as a yarn feeder that moves along the extended portion 21a of the lower looper 21. ing.
The hook-shaped portion 121d is substantially L-shaped so as to pass above the extended portion 21a of the lower looper 21 when the yarn guide lever 121 is moved from the retracted position to the threading position by the yarn path moving means. It is bent into a shape. That is, this hook-shaped portion 121d functions as a thread shifting means for moving the needle threads T1, T2 stretched over the lower looper 21 in the present embodiment to the tip side (the right side in FIGS. 1 to 3) of the lower looper 21. .
In the hook-shaped portion 121d, the length H in the X-axis direction of the portion extending above the extending portion 21a of the lower looper 21 is longer than the width h of the extending portion 21a in the X-axis direction (h < H) is formed (see FIG. 8). And the position P2 of the front-end | tip of this hook-shaped part 121d is extended to the right side in FIG. 8 rather than the position P1 of the one end of the extension part 21a. In other words, the hook-shaped portion 121d is formed of all of the needle threads T1 and T2 that are above the extension portion 21a among the needle threads T1 and T2 that are stretched over the extension portion 21a of the lower looper 21 (this embodiment). Then, it is desirable that the length be 4).

The thread guide lever base 122 is made of a plate material and is detachably attached to the lower looper holding arm 23 that supports the lower looper 21. The lower looper holding arm 23 is connected to a lower looper shaft 22 that supports the lower looper 21 at one end and rotates the lower looper 21 at the other end. That is, the moving mechanism 120 is detachably attached to the lower looper 21, and the yarn path pipe 110 provided in the moving mechanism 120 is naturally detachably attached to the lower looper 21. Will be.
A fulcrum shaft 122a that protrudes toward the yarn guide lever 121 and serves as a fulcrum when the yarn guide lever 121 rotates is formed at one end of the yarn guide lever base 122. The fulcrum shaft 122a is formed as a fulcrum shaft 122a. It is latched by the long hole 121a. The other end of the yarn guide lever base 122 is formed with a rotating shaft 122b that supports the switching lever 123 so as to be rotatable.

  The switching lever 123 is made of a plate material and is provided between the yarn guide lever 121 and the yarn guide lever base 122. An insertion hole 123a for inserting the rotation shaft 122b is formed at one end of the switching lever 123, and when the rotation shaft 122b is inserted into the insertion hole 123a, the switching lever 123 is connected to the rotation shaft 122b. Is freely rotatable. Further, a connecting shaft 123b for connecting to the thread guide lever 121 is formed at the other end of the switching lever 123, and by inserting the connecting shaft 123b of the switching lever 123 into the connecting hole 121b of the thread guide lever 121. The switching lever 123 is rotatably connected to the yarn guide lever 121.

(Detection means)
The detection sensor 130 functions as a detection unit of the present embodiment that detects that the hook-shaped portion 121d that is a yarn moving portion has moved from the retracted position by detecting that the yarn guide lever 121 has moved from the retracted position. To do.
The detection sensor 130 is fixed in the bed portion of the sewing machine frame M so as to come into contact with one end of the yarn guide lever 121 when the yarn path tube 110 is disposed at the retracted position. Further, the detection sensor 130 is separated from one end of the yarn guide lever 121 when the yarn guide lever 121 is swung so as to move the yarn path pipe 110 from the retracted position toward the threading position. . That is, whenever the yarn path pipe 110 is located at the retracted position, the switch of the detection sensor 130 is turned on, and the thread guide lever 121 is turned off by swinging. An output signal from the detection sensor 130 is input to the control unit 50 described later. In other words, the detection sensor 130 can detect the movement of the hook-shaped portion 121 d that is a yarn guide portion provided at one end of the yarn guide lever 121.

(Air blowing means)
Attached to the air blowing unit 140 is a base 141 that is movable between a spraying position close to the yarn insertion port 111 and a standby position away from the spraying position, and is attached along the moving direction of the base 141. The air nozzle 142 for blowing air to the yarn insertion port 111 is provided. The air blowing unit 140 is arranged to face the yarn insertion port 111 and blow air to the yarn insertion port 111 when the yarn hole 21b of the lower looper 21 and the yarn discharge port 112 coincide with each other. It functions as a spraying means.
As shown in FIG. 1, the threading device 100 is threaded into the threading device 100 so that one end is opened outside the machine frame M and the other end is opened above the air nozzle 142 outlet. A yarn groove 6 is provided as yarn introduction means having a possible yarn path. Then, the lower looper thread T inserted from one end opened to the outside of the sewing machine frame M and pulled from the other end is inserted into the thread insertion port 111 by blowing air pressurized by the air blowing unit 140. The

(Air spray moving means)
Further, the threading device 100 is operated as an air blowing moving means for moving the air blowing unit 140 so as to be movable between a blowing position close to the yarn insertion port 111 and a standby position away from the blowing position. A lever 4 is provided (see FIG. 1).
The operation lever 4 is fixed to the base 141, and the base 141 is also moved along the Y-axis direction in accordance with the movement of the operation lever 4. The operation lever 4 is movably locked in a groove 8 formed in the sewing machine frame M, and the user can operate the air blowing unit 140 by operating the operation lever 4. .

(Air supply means)
The air pump 150 includes a telescopic hollow bellows portion 151 and a lever portion 152 that is connected to one end portion of the bellows portion 151 and compresses the bellows portion 151. The other end of the bellows portion 151 is connected to the air nozzle 142 via the air pipe 153.
That is, by operating the lever portion 152 to compress the bellows portion 151, the air in the bellows portion 151 is sent to the air nozzle 142 through the air pipe 153 and blown out from the air outlet at the tip. Yes.

(Sewing machine control system)
A drive source such as the sewing machine motor 5 and the thread tension solenoid 34, a sensor such as the detection sensor 130, the sewing machine starting pedal 15, and the operation panel 60 are connected to the control unit 50. FIG. 10 shows only the configuration necessary for the present invention, and the control unit 50 includes other driving sources, sensors, and the like.
The control unit 50 includes an MPU (Micro Processor Unit) 51, which is a microcomputer, a ROM (Read Only Memory) 52, a RAM (Random Access Memory) 53, and an EEPROM (Electrically Erasable and Programmable ROM) 54. Yes.

  The ROM 52 stores a control program for the edge sewing machine 1. The RAM 53 is a memory that provides a work area to the MPU 51. Various data relating to sewing are backed up in the EEPROM 54. The MPU 51 performs processing in accordance with a control program stored in the ROM 52.

  Further, the control unit 50 according to the present embodiment drives the thread tension solenoid 34 to detect the thread tension of the thread tension device 30 when the output signal from the detection sensor 130 detects that the thread change lever 21 has been swung. By loosening the plate 32 (31), control is performed to release the tension of the needle threads T1, T2. In other words, the control unit 50 releases the tension of the needle threads T1 and T2 in conjunction with the hook-shaped portion 121d that is the yarn shifting portion when the yarn path tube 110 is moved from the retracted position to the threading position. It functions as a tension release means.

(Threading method to looper by threading device)
Next, the operation of the threading device 100 will be described with reference to FIGS. 1 to 3, 6, and 8.
First, the flywheel 7 provided in the sewing machine frame M is rotated to move the lower looper 21 to the threading position. At that time, it is preferable that the sewing machine frame M and the flywheel 7 are provided with indices m1 and m2, respectively, and the lower looper 21 is arranged at the threading position when the indices m1 and m2 coincide with each other.
Here, before passing the yarn through the yarn hole 21b, as shown in FIG. 2, the yarn path pipe 110 is in a state of being disposed at the retracted position. In a state in which the yarn path pipe 110 is disposed at the retracted position, the hook-like portion 121d provided at the tip (upper end) of the yarn guide lever 121 is on the left side of the needle threads T1, T2 in FIG. It is in a state of being arranged at the last retracted position in the yarn shifting operation by 121d.

Next, when a press-up lever (not shown) is operated, the switching lever 123 is rotated in the A direction about the rotation shaft 122b of FIG. 2, and the thread guide lever 121 connected to the switching lever 123 is moved on the fulcrum shaft 122a. It is rotated in the A direction as the center. The hook-shaped portion 121d is moved from the retracted position toward the threading position. At that time, the swing of the yarn guide lever 121 is detected by the detection sensor 130 disposed so as to abut one end of the yarn guide lever 121, and an output signal thereof is input to the control unit 50. Then, the controller 50 drives the yarn tension solenoid 34 in a protruding direction according to the output signal. Thereby, one thread tension tray 32 is separated from the other thread tension tray 31, and the tensions of the needle threads T1, T2 are released. That is, since the needle threads T1 and T2 are in a free state with respect to the feeding direction, the needle threads T1 and T2 can be pulled out freely.
When the thread guide lever 121 is swung from the retracted position toward the threading position, the hook-shaped part 121d is moved along the extending part 21a of the lower looper 21 toward the right side in FIGS. By passing through the needle thread path of the thread T1, the needle threads T1 and T2 are brought closer to the distal end side of the extending portion 21a.

In addition, when the yarn guide lever 121 is rotated, the yarn path pipe 110 attached to the yarn guide lever 121 is also rotated in the A direction about the fulcrum shaft 122a. When the yarn path pipe 110 is rotated, the yarn discharge port 112 moves from the retracted position shown in FIG. 2 to the threading position shown in FIG. When the yarn guide lever 121 is disposed at the threading position, the yarn discharge port 112 of the yarn path pipe 110 matches the yarn hole 21 b of the lower looper 21.
Next, the user pulls out the yarn from a yarn piece (not shown) provided in the sewing machine 200, passes the lower looper yarn T through the yarn groove 6, and inserts the leading end of the passed lower looper yarn T into the yarn insertion port 111. To do.

Next, the operation lever 4 is moved in the direction B (see FIG. 1) along the groove 8 while maintaining the state where the yarn discharge port 112 of the yarn path pipe 110 is in the threading position shown in FIG. As shown in FIG. 6, the air nozzle 142 is brought close to the yarn insertion port 111.
Next, when the lever portion 152 is moved in the C direction (see FIG. 1), the bellows portion 151 contracts, and the air in the bellows portion 151 is compressed and flows through the air pipe 153 to the air nozzle 142. Then, the air that has flowed into the air nozzle 142 is blown to the yarn insertion port 111 with the flow velocity increased at the air outlet at the tip of the air nozzle 142.
The air blown to the yarn insertion port 111 passes through the yarn path pipe 110, blows out to the back side of the lower looper 21 through the yarn discharge port 112 and the yarn hole 21b. At this time, the yarn previously inserted into the yarn insertion port 111 also passes through the yarn path pipe 110 by air, and is guided to the back side of the lower looper 21 through the yarn discharge port 112 and the yarn hole 21b. Thereby, as shown in FIG. 8, the threading operation to the lower looper 21 is completed.

  Next, the user moves the operation lever 4 in the B ′ direction and moves the switching lever 123 in the A ′ direction. As a result, the thread passage pipe 110 can be retracted to the retracted position and can be sewn in a state where the lower looper thread T is passed through the thread hole 21b of the lower looper 21.

(Effect of embodiment)
As described above, according to the sewing machine 1 according to the present invention, when the thread guide tube 110 is moved from the retracted position to the threading position, the needle thread T1 in which the hook-shaped portion 121d is stretched over the lower looper 21. The needle thread T1 traverses the needle thread path of T2, and the needle threads T1 and T2 stretched over the lower looper 21 can be brought close to the tip side of the lower looper 21. Therefore, when changing the thread of the lower looper 21, it is not necessary to cut the needle threads T1 and T2, and the thread of the lower looper 21 can be easily changed. Further, since it is not necessary to cut the needle threads T1 and T2 or remove them from the lower looper 21 when changing the thread, for example, even when sewing with a plurality of sewing needles, each sewing needle is individually provided. The thread of the lower looper 21 can be easily changed without considering the arrangement order of the passed needle threads.

(Other)
The detection sensor 130 has a switch not only on one end of the thread guide lever 121 but also on, for example, the switching lever 123, a press-up lever that interlocks with the thread guide lever and the switching lever 123, or a connecting member that interlocks with these. You may arrange | position so that it may contact | abut.
As the detection sensor 130, a photo sensor or a pressure sensor may be used.
Further, a pulse motor may be applied as the actuator of the thread tension device 30.
In the present embodiment, the tension release means of the thread tension device 30 electrically detects the movement of the hook-shaped portion 121d by the thread change detection sensor 130, and the control unit 50 drives the thread tension solenoid 34 based on the detection signal. By doing so, the tension of the needle threads T1, T2 is released according to the movement of the hook-shaped portion 121d. For example, a press-up lever that raises the cloth presser interlocked with the thread guide lever 121 is operated. At this time, the tension of the needle threads T1 and T2 may be released by releasing the thread tension plates 31 and 32 of the thread tension device 30 via a link or the like mechanically interlocked with the lever (for example, FIG. 11).
In addition, the hook-shaped portion 121d may be, for example, an annular body that is inserted into the extension portion of the lower looper 21 and moves along the extension portion, or moves along the lower surface of the extension portion. It is good also as a shape which catches the lower part of the loop of the needle thread hung over the extension part by doing.

It is a side view showing the whole sewing machine composition concerning the present invention. It is a side view which shows the threading device (retreat position) in the sewing machine which concerns on this invention. It is a side view showing the threading device (threading position) in the sewing machine according to the present invention. It is a perspective view which shows the yarn path pipe (yarn insertion port) in the sewing machine which concerns on this invention. It is a perspective view which shows the yarn path pipe (yarn discharge port) and the yarn gathering part in the sewing machine which concerns on this invention. It is the schematic perspective view which showed the air spraying unit in the sewing machine which concerns on this invention. (A) is a perspective view of a lower looper through which a thread is passed by the threading device according to the present invention, and (b) is a VII-VII sectional view of (a). It is VIII-VIII sectional drawing of FIG. It is a schematic sectional drawing which shows the thread tension apparatus in the sewing machine which concerns on this invention. It is a block diagram which shows the structure of the control part in the sewing machine which concerns on this invention. It is a schematic diagram which shows the other example to which this invention is applied. It is a side view which shows the threading device (retracting position) in the conventional sewing machine. It is a side view which shows the threading device (threading position) in the conventional sewing machine. It is a perspective view which shows the thread | yarn guide lever in the conventional sewing machine.

Explanation of symbols

1 Sewing machine
2 Needle bar 4 Operation lever (Air spray moving means)
5 Sewing motor 6 Thread groove 8 Groove 10 Upper looper drive mechanism (looper drive mechanism)
11 Upper looper 12 Upper looper holder 13 Support member 14 Operation mechanism 20 Lower looper drive mechanism (looper drive mechanism)
21 Lower looper (looper)
21a Extension part 21b Thread hole 21c Looper groove 22 Lower looper drive shaft 23 Lower looper holding arm 30 Thread tension device 31, 32 Thread tension plate 34 Thread tension solenoid (actuator, tension release means)
50 Control unit (tension release means)
DESCRIPTION OF SYMBOLS 100 Threading device 110 Yarn path pipe 111 Yarn insertion port 112 Yarn discharge port 120 Moving mechanism (yarn path moving means)
121 Thread guide lever 121a Long hole 121b Connection hole 121d Wrinkle-shaped part (yarn gathering part)
122 Yarn guide lever base 122a Support shaft 122b Rotating shaft 123 Switching lever 123a Insertion hole 123b Connection shaft 130 Detection sensor (detection means)
140 Air spraying unit (air spraying means)
141 Base 142 Air nozzle 150 Air pump (air supply means)
M Sewing machine frame T Lower looper thread (lower thread)
T1 Left needle thread (needle thread)
T2 Right needle thread (needle thread)

Claims (4)

A needle drive mechanism that drives the needle up and down by a sewing machine motor;
A looper drive mechanism comprising a looper having an extension part in which a thread hole is formed at the tip inserted into the needle thread loop by moving forward and backward in synchronization with the vertical movement of the needle;
One end is a thread insertion port, the other end is a thread discharge port, and a thread passage pipe having a thread path through which a thread can be inserted,
A thread path moving means for moving the thread path so that the thread discharge port is movable between a threading position that matches the thread hole of the looper and a retracted position away from the threading position; ,
An air blowing means disposed opposite to the yarn insertion port, for blowing air to the yarn insertion port;
An air supply means for supplying air to the air blowing means,
The yarn path pipe has a yarn moving portion that is movably provided along with the other end of the yarn path pipe and moves along the extending portion of the looper. A sewing machine characterized in that, when moved to a position, the needle thread stretched over the looper is brought close to the tip side of the looper.   The sewing machine according to claim 1, wherein the yarn feeder has a hook-like portion bent in a substantially L shape so as to pass above the looper. It has a thread tension device that applies tension to the needle thread,
The thread tension device includes tension release means for releasing the tension of the needle thread in conjunction with the thread-feeding portion when the yarn path pipe is moved from the retracted position to the threading position. The sewing machine according to claim 1 or 2.   The tension release means includes an actuator for releasing the tension of the thread tension device, a detection means for detecting movement of the yarn pulling portion, and a tension of the thread tension device by driving the actuator based on detection of the detection means. 4. The sewing machine according to claim 3, further comprising control means for releasing

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