CN1492094A - Bottom thread unwinding device - Google Patents

Abstract

A bobbin thread unwinding device is a device for unwinding bobbin thread from a bobbin thread supply source to a machine shuttle. The bobbin thread unwinding device (2) is provided with: a right thread guide (6) that guides and passes the bobbin thread (1) supplied from the bobbin thread supply source, a bobbin thread that guides and passes through the right thread guide (6) and a feeder The left thread guide (5) of the shuttle, and the bobbin thread cam (4) that rotates so that the outer peripheral surface does not interfere with the bobbin thread between the right thread guide (6) and the left thread guide (5) to tension and loosen the bobbin thread at the prescribed timing . The right thread guide (6) has a thread hole (62a) for guiding and passing the bobbin thread supplied from the bobbin thread supply source, a thread clamp unit (7) for gripping the bobbin thread passing through the thread thread hole (62a) and adjusting its tension, Guide the lower thread passing through the tensioner unit (7) and pass it through the thread hole (63a). The right thread guide (6) is integrally movable relative to the lower thread cam (4). This bobbin thread unwinding device can easily adjust the bobbin thread pouring out amount.

Description

Bottom thread unwinding device

technical field

The present invention relates to a bobbin thread unwinding device which is arranged on a lockstitch chain stitch sewing machine or a double-thread chain sewing machine, etc., and supplies bobbin thread to a machine shuttle.

Background technique

On a lockstitch chain stitch sewing machine or a double-thread chain sewing machine, between the machine shuttle in the sewing machine base plate and the supply source of the bottom thread, as shown in Figure 6, a bottom thread unwinding device 100 is provided (for example, referring to Japanese Patent No. 2762680 Bulletin).

In the bobbin thread unwinding device 100 in FIG. 6 , there are provided: a bobbin thread guide base 101 having a notch 101 a extending in a direction intersecting with the bobbin thread path, and a thread gripper unit 102 that grips the bobbin thread I and adjusts its tension. , the first, second and third thread guides 103, 104, 105 that penetrate the bottom thread I and form the holes through which it passes, and the tensioning and loosening thread guides between the second and third thread guides 104, 105 Bottom thread 1 and the bottom thread cam 106 which is linked with the sewing machine driving source and can rotate.

The second thread guide 104 and the third thread guide 105 are disposed opposite to each other with the lower thread cam 106 in between, and are supported by the lower thread guide base 101 so as to be movable along the cutout portion 101a, respectively.

The upper part of the lower thread cam 106 is arranged in the notch 101a, and the lower thread path is changed by intersecting the outer peripheral part with the lower thread path when rotating.

The bobbin thread path is formed in the order of the first thread guide 103 , the thread clamp unit 102 , the second thread guide 104 , and the third thread guide 105 .

In the bobbin thread unwinding device 100 as described above, the second and third thread guides 104, 105 are moved along the notch 101a according to the type of machine thread, etc., and the relative position with the bobbin thread cam 106 is changed to adjust the direction of the bobbin thread. The bottom line I's down line amount.

However, in the bobbin thread unwinding device 100 as described above, when the relative position of the second thread guide 104 relative to the bobbin thread cam 106 is changed, the relative position of the second thread guide 104 and the thread gripper unit 102 is also changed. Therefore, the angle at which the lower thread I is bent by the thread gripper unit 102 changes, and the length of the lower thread I clamped by the thread gripper unit 102 changes as a result, so that the frictional resistance of the lower thread I on the thread gripper unit 102 occurs. Variety. Therefore, when adjusting the rewinding amount of the bobbin thread 1, it is necessary to also consider the change of the above-mentioned frictional resistance and adjust the thread tensioner button 102c, which takes a lot of time.

In addition, for example, when using a stretchable thread such as a woolen thread as the bobbin thread, in order to prevent the bobbin thread I from stretching when it is stretched and loosened by the bobbin thread cam 106, it must not pass through the thread clamp unit 102, and it must be passed through the first thread guide 103. leads to the second wire guide 104 . Therefore, when changing the position of the second thread guide 104 when the bobbin thread I of the machine shuttle should be adjusted, the positional relationship between the second thread guide 104, the first thread guide 103 and the thread clamp unit 102 must be paid attention to, so that The thread gripper unit 102 is made not to interfere with the lower thread I, so it takes time in this part.

Contents of the invention

The object of the present invention is to provide a bobbin thread unwinding device which can easily adjust the bobbin thread I rewinding amount.

In order to solve the above-mentioned problems, the bobbin thread unwinding device of the present invention 1, as shown in FIGS. The bottom thread cam 4 that rotates is set on the sewing machine M that forms stitches through the coordinated action of the machine needle and the machine shuttle, and the bottom thread I is poured out from the bottom thread supply source to the machine shuttle. It is characterized in that:

a first thread guide (for example, the right thread guide 6) that guides and passes the bobbin thread I supplied from the above-mentioned bobbin thread supply source, and

The second thread guide (for example, left thread guide 5),

The first thread guide 6 has a first hole (for example, thread hole 62a) for guiding and passing the bobbin thread I supplied from the bobbin thread supply source, and a bobbin thread I that passes through the first hole 62a to be held and adjusted. The tensioner unit 7 and the second hole (for example, thread hole 63 a ) through which the bobbin thread I is guided through the thread gripper unit 7 are relatively movable relative to the bobbin thread cam 4 as a whole.

The bobbin thread unwinding device according to the first aspect of the present invention includes a first hole for guiding and passing the bobbin thread supplied from the bobbin thread supply source, and a thread gripper for gripping the bobbin thread passing through the first hole and adjusting its tension. The unit, and the first thread guide that guides the lower thread through the tensioner unit and the second hole through which it passes, can move integrally with respect to the lower thread cam, that is, the first hole and the tensioner unit and the second The hole portion is integrally movable relative to the lower thread cam. Therefore, when the second hole is moved relative to the lower thread cam to adjust the amount of the bobbin thread unwound to the hook, the first hole and the thread tensioner unit move integrally with the second hole, and maintain the first and second holes. The relative position of the second hole and the tensioner unit. Therefore, when the second hole is moved relative to the lower thread cam, the bending angle of the lower thread on the thread clamp unit is not changed, and the length of the portion of the lower thread clamped by the thread clamp unit can be kept constant. Keep the frictional resistance of the lower thread on the tensioner unit constant. Therefore, unlike conventional ones, it is not necessary to adjust the thread tensioner unit in consideration of changes in the frictional resistance on the thread tensioner unit, and it is possible to easily adjust the amount of bobbin thread feeding to the hook.

The bobbin thread unwinding device of the present invention 2, as shown for example in Figures 1 to 5, is the bobbin thread unwinding device according to the present invention 1, characterized in that:

The tensioner unit 7 is deviated from the straight line connecting the first hole 62a and the second hole 63a.

According to the bobbin thread unwinding device according to the second aspect of the present invention, since the thread gripper unit deviates from the straight line connecting the first hole and the second hole, the bobbin thread does not pass through the thread gripper unit but passes from the first hole to the bottom thread. In the second hole, the thread clamp unit does not interfere with the lower thread. Therefore, for example, when using a stretchable thread such as a wool thread as the lower thread, the second hole can be moved relative to the lower thread cam without being limited by the position of the first hole and the thread clamp unit unlike conventional ones. That is, it is possible to easily adjust the bobbin thread feeding amount to the hook without being limited by the positional relationship between the first hole portion and the second hole portion and the thread tensioner unit.

Description of drawings

Fig. 1 is a perspective view of a sewing machine provided with a bobbin thread unwinding device of the present invention.

Fig. 2 is a top view of the bobbin thread unwinding device of the present invention.

Fig. 3 is a perspective view of the bobbin thread unwinding device and the auxiliary lower shaft of the present invention.

Fig. 4 is a partial view of the bobbin thread unwinding device of the present invention.

Fig. 5 is a perspective view of the right thread guide.

Fig. 6 is an explanatory diagram of a conventional thread unwinding device.

In the figure: 2-bottom thread unwinding device, 4-bottom thread cam, 5-left thread guide (second thread guide), 6-right thread guide (first thread guide), 7-thread clamp unit, 62a-thread hole (first hole), 63a-guide thread hole (second hole), I-bottom thread, M-sewing machine.

Detailed ways

Hereinafter, embodiments of the bobbin thread unwinding device 2 of the present invention will be described in detail with reference to the drawings.

The bobbin thread unwinding device 2 as an example of the present invention is inside the sewing machine M shown in FIG. A device for pouring out to a shuttle (not shown). In addition, the so-called machine shuttle is a device that cooperates with machine needles to form stitches.

The sewing machine M consists of a base plate 1 with a base plate surface, a vertical body part T standing up from the base plate right part 1a of the right side part of FIG. Head A poses. And the needle is omitted in Fig. 1 . In addition, in FIG. 1 , the front side is the operator's side, and the right side is the upstream side of the bobbin thread path.

The bottom plate 1 has a flat cube shape, and a concave portion 1b opened toward the operator's side and upward is formed at the center thereof. The right wall of the concave portion 1b is the left end wall portion 1c of the bottom plate right portion 1a. Furthermore, on the bottom plate 1, there is provided a hood C that is rotatable relative to the lower end of the bottom plate 1, and is used to open and close the recessed portion 1b. The upper surface of the hood C is configured to be flush with the floor surface when the hood C is closed. In addition, when the hood C is closed, an opening (not shown) is formed between the hood C and the bottom plate right portion 1a. This opening guides the bobbin thread I supplied from the bobbin thread supply source to the concave portion 1b.

In addition, a machine shuttle, a lower shaft (not shown) rotated by a sewing machine motor (not shown), and an auxiliary lower shaft 12 that rotates in the direction of the arrow in FIG. wait.

The lower shaft is a shaft that rotates synchronously with the upper shaft (not shown) that drives the needle bar. A sprocket (not shown) (hereinafter referred to as a lower shaft sprocket for convenience) is fixed to this lower shaft, and a timing belt ( not shown).

The auxiliary lower shaft 12 is provided on the operator's side of the chassis 1 and is substantially parallel to the lower shaft. The auxiliary lower shaft 12, as shown in FIG. 3, is rotatably supported by a right bearing 12a, a center bearing 12b, and a left bearing 12c, which are fixed to a frame at the right portion 1a of the floor. The sprocket 12f is fixed to the auxiliary lower shaft 12 thus rotatably supported, and the above-mentioned timing belt hung on the sprocket for the lower shaft is also hung on the sprocket 12f. Therefore, when the lower shaft rotates, the auxiliary lower shaft 12 is rotated by the lower shaft sprocket, the timing belt, and the sprocket 12f. In addition, the rotation transmission of the auxiliary lower shaft 12 from the lower shaft may be performed by gears instead of a timing belt.

In addition, slide retaining rings 12d, 12d are fitted on both sides of the center bearing 12b on the auxiliary lower shaft 12, and are fixed with screws 12e, 12e. Accordingly, the auxiliary lower shaft 12 is in a state where movement in the axial direction is restricted. The left end of the left bearing 12c protrudes from the left end wall 1c of the right bottom plate 1a, and the left end of the auxiliary lower shaft 12 protrudes further into the recess 1b than the left bearing 12c. The lower thread guide base 3 is attached to the left bearing 12c.

The lower thread guide base 3, as shown in FIGS. The wiring board 33 is formed.

The mounting part 31 has a hole 31a, and as shown in FIG. 3, the left bearing 12c protruding from the left end wall 1c is inserted into the hole 31a and fixed to the left bearing 12c with a base screw 31b.

The flat surface portion 32 is provided so as to protrude from the upper portion of the mounting portion 31 and has a substantially 9-shape when viewed from the side of the mounting portion 31 . The inclination of the upper surface of the flat surface portion 32 can be adjusted by loosening the base screw 31b and rotating the mounting portion 31 relative to the left bearing 12c.

The lead plate 33 has an elongated slit 33a in the center and is approximately U-shaped in plan view, and is fixed to the flat surface 32 with screws (not shown) while opening toward the operator. On the upper surface of the wire guide plate 33, the central wire guide 9, the left and right wire guides 5, 6, and the clamp unit 7 are disposed.

The central wire guide 9 is slightly F-shaped in plan view. In more detail, the central wire guide 9 has a substantially L-shaped fixing portion 9b fixed to the wire guide plate 33 by screws 9a, 9a, and a guide portion 9c that stands up from the fixing portion 9b and extends toward the operator. constitute. The guide portion 9c is disposed above the slit portion 33a, and has a long hole portion 9d extending between both ends thereof. The bobbin thread unwinding device 2 is provided in a state of sandwiching the guide portion 9c from the left and right.

As shown in FIG. 2 , the lower thread unwinding device 2 is provided in the recess 1 b of the bottom plate 1 . In addition, the bottom line I is shown as a thick line in FIG. 2 . On the path of the base line I, the upper right side in FIG. 2 is the upstream side, and the left side is the downstream side.

In this bobbin thread unwinding device 2, the left and right thread guides 5, 6 arranged on the left and right sides of the slit portion 33a of the bobbin thread guide base 3 engage (interfere) with the bobbin thread I between the left and right thread guides 5, 6 with the outer peripheral surfaces. The bottom thread cam 4 that can rotate constitutes.

The right thread guide 6 (first thread guide) guides and passes the bobbin thread I supplied from the bobbin thread supply source, and supplies it to the long hole portion 9d of the central thread guide 9 . This right thread guide 6, as shown in FIGS. The main body 61, the thread clamp unit 7 for clamping the lower thread I and adjusting its tension, the upright part 62 standing up from the right end of the right thread guide body 61, and the upright part 63 standing up from the left end of the right thread guide body 61 constitute.

The right wire guide body 61 is fixed on the upper side of the wire guide plate 33 by the screw 61b passing through the notch 61a, and the operator's side end, by loosening the screw 61b, the screw 61b can be moved along the gap within the range of the notch 61a. The part 33a moves.

On the upper surface of the right thread guide body 61, the thread gripper unit 7 is fixed. The thread clamp unit 7 is composed of a fixed thread clamping disk (hereinafter referred to as a fixed disk) 71a that is restricted from moving, moves in a direction of moving away from the fixed disk 71a, and clamps the lower thread I with the fixed disk 71a. Movable thread clamping plate (hereinafter referred to as movable plate) 71b, thread clamping spring 72 for pressing movable plate 71b relative to fixed plate 71a, thread clamping shaft 73 and thread clamping knob for adjusting the clamping force on bobbin thread I 74 constitute. This thread clamp unit 7 adjusts the power of clamping the bottom thread 1 with the method of rotating the thread clamp button 74 . In this embodiment, the right thread guide body 61 also serves as the fixing plate 71a.

The movable plate 71b is a rectangular plate abutting against the fixed plate 71a, that is, the right thread guide body 61 . Since the end of the movable disk 71b facing the operator is bent and separated from the right thread guide body 61, the bobbin thread I is easily caught between the movable disk 71b and the fixed disk 71a. A through hole (not shown) penetrating through the thread tension shaft 73 is provided at the operator's side end of the movable platen 71b. In addition, an anti-rotation leg 711 for preventing the rotation of the movable disc 71b is provided at the end portion of the movable disc 71b on the operator's side, and the anti-rotation leg 711 is fixed to the right thread guide body 61 .

The clamping shaft 73 protrudes from the right thread guide body 61 and passes through the through hole of the movable disk 71b. An external threaded portion (not shown) is provided on the outer peripheral portion of the thread clamping shaft 73 , and a thread clamping button 74 having an internal thread portion (not shown) on the inner peripheral portion is screwed to the front end of the thread clamping shaft 73 . In addition, the tension shaft 73 is inserted inside the tension spring 72 . The clamping spring 72 is located between the movable disc 71b and the clamping button 74, and is pressed by the movable disc 71b and the clamping button 74.

The upright portion 62 has a wire hole (first hole portion) 62a penetrating in the left-right direction. The guide hole 62a is a means for guiding the lower thread I supplied from the lower thread supply source to pass through the inside and supply it to the thread tensioner unit 7 .

The upright portion 63 has a wire hole (second hole portion) 63 a penetrating in the left-right direction and facing the long hole portion 9 d of the center wire guide 9 . The thread hole 63a is a device for guiding the bobbin thread I passing through the thread clamp unit 7 to pass inside and supply it to the long hole portion 9d of the center thread guide 9 .

The left thread guide 5 (second thread guide) is a device that guides the bobbin thread I passed through the long hole portion 9d of the center thread guide 9, passes it, and supplies it to the machine shuttle. The left thread guide 5, as shown in FIG.

The left thread guide body 51 is fixed to the operator's side end on the right side of the upper surface of the thread guide plate 33 by a screw 51b passing through the hole 51a. The hole portion 51 a extends along the slit portion 33 a of the lead plate 33 . Therefore, by loosening the screw 61b, the left guide body 51 can be moved along the slit portion 33a within the range of the hole portion 51a.

The upright portion 52 has a wire hole 52 a penetrating in the left-right direction and facing the long hole portion 9 d of the center wire guide 9 . The thread hole 52a is a device for guiding the bobbin thread I passed through the elongated hole portion 9d of the center thread guide 9 to pass inside and supply to the hook.

The bobbin thread cam 4 is a device that rotates to go in and out of the outer peripheral surface from the slit 33a of the bobbin thread guide base 3, thereby tensioning and loosening the bobbin thread I between the left and right thread guides 5, 6 at predetermined timing. The bobbin thread cam 4 is composed of half-moon-shaped plates 4a, 4b arranged side by side in a roughly half-moon shape, a connecting portion (not shown) for integrally fixing the two half-moon-shaped plates 4a, 4b to the auxiliary lower shaft 12, and the like. Attached to the end of the auxiliary lower shaft 12 protruding to the left from the left bearing 12c.

The half-moon plate 4a has an outer peripheral shape composed of a circular arc portion 4c and a straight portion 4e, and a penetrating auxiliary lower shaft 12 is provided near the straight portion 4e. This half-moon plate 4a is arranged on the right side with respect to the half-moon plate 4b. The half-moon plate 4b has an outer peripheral shape composed of a circular arc portion 4d and a straight portion 4f, and a penetrating auxiliary lower shaft 12 is provided near the straight portion 4f. The straight portion 4f of the half-moon plate 4b and the straight portion 4e of the half-moon plate 4a are arranged parallel to each other. A cylindrical hub 41 is fixed to the half-moon plate 4b. The hub 41 is embedded in the shaft end of the auxiliary lower shaft 12 and fixed on the shaft end with screws.

The connecting portion is integrated with the half-moon plates 4a, 4b, and separates the half-moon plates 4a, 4b in the axial direction of the auxiliary lower shaft 12 so as to face the guide portion 9c in the gap portion 33a of the guide plate 33. The side state is fixed on the auxiliary lower shaft 12. Therefore, the half-moon plates 4 a , 4 b are integrally rotated with the rotation of the auxiliary lower shaft 12 . In addition, due to the rotation of the half-moon plates 4a, 4b, when the straight portions 4e, 4f are approximately parallel to the lead plate 33, the straight portions 4e, 4f are located below the upper surface of the lead plate 33.

Next, the procedure for forming the above-mentioned bobbin thread unwinding device 2 will be described.

First, the lower thread guide base 3 is mounted on the left bearing 2 mounted on the auxiliary lower shaft 12 with the base screw 31b. Then, the lower thread cam 4 is fixed on the auxiliary lower shaft 12 with screws. Then, the half-moon plates 4a, 4b of the lower thread cam 4 are inserted into the slits 33a of the guide plate 33, and the guide plate 33 is fixed on the flat surface 32 with screws (not shown). Subsequently, the guide portion 9c is put between the half-moon plates 4a, 4b of the lower thread cam 4, and the center thread guide 9 is fixed to the guide plate 33 with the screws 9a, 9a. In addition, the left and right thread guides 5, 6 are mounted on the thread guide plate 33 with the screws 51b, 61b, and the thread clamp unit 7 is fixed on the right thread guide 6.

Next, the procedure for threading the lower thread I on the lower thread unwinding device 2 formed above will be described.

First, open the cover C to expose the lower thread cam 4. Then, turn the auxiliary lower shaft 12 by hand and make the linear portions 4e, 4f of the half-moon plates 4a, 4b of the lower thread cam 4 slightly parallel to the guide plate 33, so that the linear portions 4e, 4f are located below the upper surface of the guide plate 33 and The thread hole 62 a of the right thread guide 6 and the thread hole 52 a of the left thread guide 5 are made to face the long hole portion 9 d of the central thread guide 9 .

Then, maintaining this state, the bobbin thread I supplied from the bobbin thread supply source is supplied to the machine shuttle. Specifically, first, the bobbin thread I supplied from the bobbin thread supply source is passed through the inside of the threading hole 62a of the right thread guide 6 . Next, the lower thread I passed through the thread hole 62a passes between the movable disk 71b and the fixed disk 71a of the thread tensioner unit 7 . Finally, the bobbin thread I passed through the thread clamp unit 7 is passed through the thread hole 63a of the right thread guide 6, the long hole portion 9d of the central thread guide 9, and the thread hole 52a of the left thread guide 5 arranged in a straight line, and then supplied. to the shuttle.

The sewing machine M that has passed through the lower thread I on the lower thread unwinding device 2, the lower thread cam 4 is rotated by the driving of the sewing machine motor, and the arc portions 4c, 4d of the half-moon plates 4a, 4b are drawn from the slit portion 33a of the guide plate 33. At this time, the lower thread 1 is hung on the circular arc parts 4c, 4d, and due to the rotation of the lower thread cam 4, it passes through the end opposite to the operator's side on the long hole part 9d of the central thread guide 9. status of the department. Therefore, when the lower thread cam 4 rotates and the lower thread I is in a state of being hung on the circular arc portions 4c, 4d, the lower thread I is in a state of being pulled outward (tensioned).

Then, when the lower thread cam 4 is rotated and the arc portions 4c, 4d are in a state of sinking downward from the slit portion 33a, the path between the guide holes 63a, 52a is the shortest and the lower thread I is loosened (loose) and passed through the elongated hole portion. Manipulator side within 9d.

In this way, the lower thread unwinding device 2, due to the rotation of the lower thread cam 4, tensions and loosens the lower thread I at a predetermined moment, and the lower thread I that has been loosened in length is rewound to the shuttle. And, by moving the left thread guide 5 and the right thread guide 6 along the slit 33a within the range of the notch 61a or the hole 51a, that is, moving the thread holes 63a, 52a and the lower thread cam 4 relatively, the lower thread can be adjusted. The amount by which the cam 4 draws out the lower thread, that is, the amount by which the lower thread I is fed to the shuttle. Specifically, by moving the guide thread holes 63a, 52a toward the operator's side relative to the lower thread cam 4, the amount of the lower thread to be fed to the shuttle can be increased. In addition, by moving the thread thread holes 63a, 52a to the side opposite to the operator's side with respect to the lower thread cam 4, the amount of the lower thread to be fed out to the hook can be reduced.

According to the above-mentioned bobbin thread unwinding device 2, the right thread guide 6 has a gripper that guides the bobbin thread I supplied from the bobbin thread supply source to pass through the inner threading hole 62a, clamps the bobbin thread I passing through the threading hole 62a, and adjusts its tension. The thread guide unit 7 and the lower thread I guided through the thread gripper unit 7 pass through the inner thread hole 63a, and the right thread guide 6 can move integrally with respect to the lower thread cam 4. Therefore, when the thread hole 63a is moved relative to the slit portion 33a of the lower thread guide base 3 in order to adjust the amount of the bobbin thread unwound to the hook, that is, when the thread hole 63a is moved relative to the bobbin thread cam 4, the thread hole 62a and The tensioner unit 7 and the wire hole 63a move integrally, maintaining the relative positions of the wire holes 63a, 52a and the wire gripper unit 7 . Therefore, even when the thread guide hole 63a is moved relative to the lower thread cam 4, the bending angle of the lower thread I on the thread gripper unit 7 does not change, and the length of the lower thread I gripped by the thread gripper unit 7 can be maintained. Certain, therefore, can keep the frictional resistance of the bottom line 1 on the thread clamp unit 7 to be constant. Therefore, it is not necessary to adjust the thread gripper unit 7 in consideration of the change of the frictional resistance on the thread gripper unit 7 unlike conventional ones, so the amount of thread rewinding to the bobbin thread I of the shuttle can be easily adjusted.

In addition, since the thread clamp unit 7 deviates from the straight line connecting the thread hole 62a and the thread hole 63a, so when the bottom thread 1 passes through the thread hole 63a from the thread hole 62a without passing through the thread thread hole 63a, the thread grip unit 7 is not in contact with the thread hole 63a. Bottom line I interfere. Therefore, when a stretchable thread such as wool thread is used as the lower thread, the thread hole 63a can be moved relative to the lower thread cam 4 without being limited by the positions of the thread hole 62a and the thread clamp unit 7 unlike conventional ones. That is, it is possible to easily adjust the amount of the bobbin thread I fed to the hook without being restricted by the positional relationship between the thread guide holes 63a, 52a and the thread gripper unit 7 .

In addition, in the above description, it has been described that the tensioner unit 7 uses the tension spring 72 to press the movable disk 71b against the fixed disk 71a, but it is not limited to this, and an electric motor such as a solenoid or a voice coil motor can also be used. Drive mechanism.

In addition, it has been described that the shape of the movable platen 71b is formed into a rectangular plate shape, but other shapes may also be used. In addition, although it has been described that the anti-rotation leg 711 is provided on the movable platen 71b, the anti-rotation leg 711 may not be provided.

(invention effect)

According to the bobbin thread unwinding device of the present invention 1, even when the second hole portion moves relative to the bobbin thread cam, the bending angle of the bobbin thread on the thread gripper unit does not change, and the portion of the bobbin thread gripped by the thread gripper unit can be held. The length is constant, so that the frictional resistance of the bobbin thread on the thread tensioner unit can be kept constant. Therefore, unlike conventional ones, it is not necessary to adjust the thread tensioner unit in consideration of changes in the frictional resistance on the thread tensioner unit, and it is possible to easily adjust the amount of bobbin thread poured out to the hook.

According to the bobbin thread unwinding device of the present invention 2, the same effect as that of the present invention 1 can be obtained, so, for example, when using a stretchable thread such as a woolen thread as the bobbin thread, unlike conventional ones, it is not affected by the first hole. And the limitation of the position of the thread clamp unit, the second hole can be moved relative to the lower thread cam. That is, it is possible to easily adjust the feeding amount of the bobbin thread I to the hook without being limited by the positional relationship between the first hole portion and the second hole portion and the thread tensioner unit.

Claims (2)

1. A bobbin thread unwinding device, which has a bobbin thread cam that can press the outer peripheral surface against the bobbin thread and rotate to tension and loosen the bobbin thread at a predetermined moment, and is set at the place where the stitches are formed by the cooperative action of the needle and the shuttle. On the sewing machine, and the bottom thread is poured out from the bottom thread supply source to the machine shuttle, it is characterized in that: The first thread guide, the first thread guide has a first hole for guiding and passing the bobbin thread supplied from the bobbin thread supply source, and a clamping thread for clamping the bobbin thread passing through the first hole and adjusting its tension. and a second hole for guiding and passing the bobbin thread passed through the thread gripper unit; guiding and passing the bobbin thread supplied from the bobbin thread supply source, and a second thread guide disposed on a side closer to the shuttle than the first thread guide and guiding and passing the bobbin thread passed through the first thread guide to feed the shuttle, The first thread guide is integrally movable relative to the lower thread cam. 2 . The bobbin thread rewinding device according to claim , wherein the thread clamp unit deviates from a straight line connecting the first hole and the second hole. 3 .

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