JP5241192B2 - Lower thread tension adjustment device - Google Patents

Description

  The present invention relates to a bobbin thread tension adjusting device.

A bobbin case around which a lower thread is wound is accommodated in the sewing machine hook. As the hook rotates, the lower thread is fed out with a predetermined tension applied, and is entangled with the upper thread to form a seam.
The bobbin case is attached to the inner hook provided inside the outer hook, and a lower thread tension adjusting plate for adjusting the tension applied to the lower thread that is fed out is provided on the outer periphery of the bobbin case by a tension adjusting screw. It is attached so that the tension of can be adjusted. The tension adjustment screw can be screwed toward the center of the bobbin case. By screwing toward the center of the bobbin case, the gap between the bobbin case and the lower thread tension adjustment plate is reduced, so the tension applied to the lower thread is increased. be able to.
The tension adjustment screw loosens or tightens the bobbin thread tension adjustment plate with respect to the bobbin case by a screwdriver that can be moved back and forth between an engagement position that engages with the tension adjustment screw and a standby position that is separated from the engagement position. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 8-47590

  By the way, the hook is locked by a pressing member provided on the sewing machine frame, so that the rotation is prevented and the lower hook is fed out to the rotating outer hook. It is necessary to provide a gap for passing the upper thread between the inner hook and the gap between the inner hook and the pressing member. Therefore, the rotational position of the inner hook is not completely fixed. Therefore, even if the driver is engaged with the tension adjusting screw of the bobbin case attached to the inner hook, the position of the tension adjusting screw relative to the tip of the driver is not fixed due to the rattle of the inner hook, and both are engaged. This is a problem that the tension of the lower thread cannot be adjusted. In addition, the bobbin case housed in the inner hook also rattles in the inner hook, so there was a similar problem.

  Accordingly, the present invention has been made to solve the above-described problems, and can adjust the lower thread tension with a simple configuration even if the inner hook or the bobbin case is loose. An object is to provide an apparatus.

The invention according to claim 1 is provided on the outer periphery of a bobbin case accommodated in an inner hook provided rotatably with respect to the outer hook of the sewing machine, and the lower thread fed from the bobbin in the bobbin case is A lower thread tension applying portion that is sandwiched between the bobbin case outer peripheral surface and applying tension to the lower thread, and the lower thread tension applying portion is attached to the outer peripheral surface of the bobbin case and the lower thread tension applying portion is applied to the lower thread. A tension adjusting screw for adjusting the tension to be engaged, an engaging portion formed to be engageable with the tension adjusting screw so as to rotate the tension adjusting screw, and engaging the engaging portion with the tension adjusting screw. A moving means capable of advancing and retreating to an engaging position and a standby position separated from the engaging position, and a rotation driving means for rotating the engaging portion when the engaging portion is engaged with the tension adjusting screw. , With bobbin thread tension adjusting device Before the engagement portion approaches and engages with the tension adjusting screw, at least one of the inner hook and the bobbin case is rotated in contact with at least one of the inner hook and the bobbin case. A pressing mechanism that presses toward the door , and the pressing mechanism is in contact with at least one of the inner hook and the bobbin case in conjunction with the advancement and retraction of the engaging portion by the moving means, and this position. It has the elastic member which can advance and retreat between the positions isolated from the.

According to the first aspect of the present invention, the lower thread tension applying portion and the bobbin are obtained by moving the engaging portion closer to the tension adjusting screw by the moving means and engaging the tension adjusting screw, and then rotating the engaging portion by the rotation driving means. The gap with the outer peripheral surface of the case can be adjusted, and the tension applied to the lower thread can be adjusted.
Here, the lower thread tension adjusting device is provided with a pressing mechanism, and this pressing mechanism is at least one of the inner hook and the bobbin case before the engaging portion approaches and engages with the tension adjusting screw. Abut against one side and press at least one of the inner hook and the bobbin case in the rotational direction.
Thus, the inner hook and the bobbin case are positioned at predetermined positions by the pressing mechanism, and the engaging portion can be easily engaged with the tension adjusting screw with a simple configuration, and the tension of the lower thread can be adjusted. it can.

In addition , since the elastic member is interlocked with the advancement and retraction of the engagement portion, the drive source for the engagement portion and the elastic member can be made one.
Therefore, the number of parts can be reduced, and downsizing, weight reduction, and cost reduction can be achieved.

The invention according to claim 2 is provided on the outer periphery of a bobbin case accommodated in an inner hook provided rotatably with respect to the outer hook of the sewing machine, and the lower thread fed from the bobbin in the bobbin case is A lower thread tension applying portion that is sandwiched between the bobbin case outer peripheral surface and applying tension to the lower thread, and the lower thread tension applying portion is attached to the outer peripheral surface of the bobbin case and the lower thread tension applying portion is applied to the lower thread. A tension adjusting screw for adjusting the tension to be engaged, an engaging portion formed to be engageable with the tension adjusting screw so as to rotate the tension adjusting screw, and engaging the engaging portion with the tension adjusting screw. A moving means capable of advancing and retreating to an engaging position and a standby position separated from the engaging position, and a rotation driving means for rotating the engaging portion when the engaging portion is engaged with the tension adjusting screw. , With bobbin thread tension adjusting device Before the engagement portion approaches and engages with the tension adjusting screw, at least one of the inner hook and the bobbin case is rotated in contact with at least one of the inner hook and the bobbin case. A pressing mechanism that presses toward the front, and the pressing mechanism includes a contact portion that can advance and retract between a position that contacts at least one of the inner hook and the bobbin case and a position that is isolated from this position. It has the cylinder apparatus which has at the front-end | tip.

According to the second aspect of the present invention, the lower thread tension applying portion and the bobbin are obtained by moving the engaging portion closer to the tension adjusting screw and engaging the moving portion with the moving means, and then rotating the engaging portion with the rotation driving means. The gap with the outer peripheral surface of the case can be adjusted, and the tension applied to the lower thread can be adjusted.
Here, the lower thread tension adjusting device is provided with a pressing mechanism, and this pressing mechanism is at least one of the inner hook and the bobbin case before the engaging portion approaches and engages with the tension adjusting screw. Abut against one side and press at least one of the inner hook and the bobbin case in the rotational direction.
Thus, the inner hook and the bobbin case are positioned at predetermined positions by the pressing mechanism, and the engaging portion can be easily engaged with the tension adjusting screw with a simple configuration, and the tension of the lower thread can be adjusted. it can.
Further , since the cylinder device can be driven independently of the moving means, adjustment of the engagement position between the engagement portion and the tension adjusting screw and adjustment of the contact position between the inner hook or the bobbin case and the contact portion can be performed. Can be done separately and independently.
Therefore, as compared with the case to link a mobile device engaging portion and the elastic member as in claim 1, it facilitates the adjustment of the engaging position and the contact position.

According to a third aspect of the invention, the lower thread tension adjusting device according to claim 2, in conjunction with the advance and retreat of the engaging portion by said moving means, characterized in that for advancing and retreating the abutment.

According to the third aspect of the invention, since the cylinder device is interlocked with the advancement and retraction of the engagement portion, the operation control of the engagement portion and the cylinder device can be easily performed with one control system.

According to a fourth aspect of the present invention, in the lower thread tension adjusting device according to any one of the first to third aspects, for example, the engaging portion 4 engages with the tension adjusting screw 3 in FIG. The engaging position is on a straight line Y that intersects the axis O of the inner hook 12 within a range of 15 ° to 50 ° with respect to the vertical line X orthogonal to the axis O of the inner hook 12. To do.
Here, the axis O of the inner hook refers to the rotation axis of the inner hook, and in FIG. 12, it indicates a line extending from the front surface to the rear surface of the sheet.

According to the invention described in claim 4 , as shown in FIG. 12, the engaging position where the engaging portion 4 engages with the tension adjusting screw 3 is relative to the vertical line X perpendicular to the axis O of the inner hook 12. And on a straight line Y that intersects on the axis O of the inner hook 12 within a range of 15 ° to 50 °. Therefore, the tension adjusting screw 3 exists in a range where the lower end angle of the outer hook spring 11b when the outer hook 11 is stopped does not come into contact with the feed arm 30 that moves the feed dog 32, and the lower thread tension adjusting device. Can advance and retreat.
Therefore, by setting the lower thread tension adjusting device in the range of 15 ° to 50 ° described above, a general sewing machine or a shuttle can be used, and the cost can be reduced.

According to the first aspect of the present invention, the lower thread tension applying portion and the bobbin are obtained by moving the engaging portion closer to the tension adjusting screw by the moving means and engaging the tension adjusting screw, and then rotating the engaging portion by the rotation driving means. The gap with the outer peripheral surface of the case can be adjusted, and the tension applied to the lower thread can be adjusted.
Here, the lower thread tension adjusting device is provided with a pressing mechanism, and this pressing mechanism is at least one of the inner hook and the bobbin case before the engaging portion approaches and engages with the tension adjusting screw. Abut against one side and press at least one of the inner hook and the bobbin case in the rotational direction.
Thus, the inner hook and the bobbin case are positioned at predetermined positions by the pressing mechanism, and the engaging portion can be easily engaged with the tension adjusting screw with a simple configuration, and the tension of the lower thread can be adjusted. it can.

In addition , since the elastic member is interlocked with the advancement and retraction of the engagement portion, the drive source for the engagement portion and the elastic member can be made one.
Therefore, the number of parts can be reduced, and downsizing, weight reduction, and cost reduction can be achieved.

According to the second aspect of the present invention, the lower thread tension applying portion and the bobbin are obtained by moving the engaging portion closer to the tension adjusting screw and engaging the moving portion with the moving means, and then rotating the engaging portion with the rotation driving means. The gap with the outer peripheral surface of the case can be adjusted, and the tension applied to the lower thread can be adjusted.
Here, the lower thread tension adjusting device is provided with a pressing mechanism, and this pressing mechanism is at least one of the inner hook and the bobbin case before the engaging portion approaches and engages with the tension adjusting screw. Abut against one side and press at least one of the inner hook and the bobbin case in the rotational direction.
Thus, the inner hook and the bobbin case are positioned at predetermined positions by the pressing mechanism, and the engaging portion can be easily engaged with the tension adjusting screw with a simple configuration, and the tension of the lower thread can be adjusted. it can.
Further , since the cylinder device can be driven independently of the moving means, adjustment of the engagement position between the engagement portion and the tension adjusting screw and adjustment of the contact position between the inner hook or the bobbin case and the contact portion can be performed. Can be done separately and independently.
Therefore, as compared with the case to link a mobile device engaging portion and the elastic member as in claim 1, it facilitates the adjustment of the engaging position and the contact position.

According to the third aspect of the invention, since the cylinder device is interlocked with the advancement and retraction of the engagement portion, the operation control of the engagement portion and the cylinder device can be easily performed with one control system.

According to the fourth aspect of the present invention, the engaging position where the engaging portion engages with the tension adjusting screw is within the range of 15 ° to 50 ° with respect to the vertical line perpendicular to the axis of the inner hook. It is on a straight line that intersects on the axis. For this reason, the tension adjusting screw exists in a range where the lower end angle of the outer hook spring when the outer hook is stopped does not come into contact with the feed arm that moves the feed dog, and the lower thread tension adjusting device can be advanced and retracted. .
Therefore, by setting the lower thread tension adjusting device in the range of 15 ° to 50 ° described above, a general sewing machine or a shuttle can be used, and the cost can be reduced.

Hereinafter, the best mode of a lower thread tension adjusting device according to the present invention will be described in detail with reference to the drawings.
[Embodiment 1]
<Configuration of bobbin thread tension adjusting device>
As shown in FIGS. 1 and 2, the lower thread tension adjusting device 1 is provided in the vicinity of a sewing machine hook 10. The shuttle 10 is attached to a lower shaft (not shown) connected to a sewing machine motor (not shown). When the lower shaft rotates around the axis by driving the sewing machine motor, the shuttle 10 also rotates around the axis of the lower shaft. To do. The hook 10 includes an outer hook 11 attached to the lower shaft, and an inner hook 12 that is rotatably provided inside the outer hook 11. The outer hook 11 is formed with a sword tip 11a for catching an upper thread passed through a sewing needle. A bobbin case 13 is detachably attached to the inner pot 12 inside. Further, the rotation of the inner hook 12 around the lower shaft of the inner hook 12 is restricted by an inner hook press 14 as a rotation restricting member. Specifically, the inner hook 12 is formed with a recess 12a, and the inner hook retainer 14 is formed with a protrusion 14a that fits into the recess 12a so as to protrude toward the back with respect to the paper surface of FIG. The rotation of the inner hook 12 is restricted by fixing the inner hook retainer 14 in a state in which the protrusion 14a is fitted in the recess 12a. As shown in FIG. 3, the inner hook retainer 14 has a base end portion 14 b fixed to the sewing machine frame F.

  The bobbin case 13 accommodates a bobbin 15 around which a lower thread T is wound. On the outer periphery of the bobbin case 13, tension is applied as a lower thread tension applying portion for applying tension to the lower thread T by sandwiching the lower thread T fed from the bobbin 15 in the bobbin case 13 with the outer peripheral surface of the bobbin case 13. The plate 2 is attached to the bobbin case 13 by a fixing screw 13a and a tension adjusting screw 3.

  The tension adjusting screw 3 is formed so as to be able to be screwed into a screw hole formed on the outer peripheral surface of the bobbin case 13, and is screwed into the screw hole and rotated clockwise while passing through the tension applying plate 2. Thus, the tension applied to the lower thread T by the tension applying plate 2 can be adjusted. That is, by increasing the amount by which the tension adjusting screw 3 is screwed into the screw hole of the bobbin case 13, the gap between the outer peripheral surface of the bobbin case 13 and the tension applying plate 2 is reduced, and the tension applied to the lower thread T can be increased. . On the other hand, by rotating the tension adjusting screw 3 counterclockwise from the bobbin case 13, the pressing force of the tension applying plate 2 against the bobbin case 13 by the tension adjusting screw 3 can be weakened, and the tension applied to the lower thread T Can also be weakened.

In the vicinity of the hook 10, an engaging portion formed to be engageable with the tension adjusting screw 3 so that the tip end portion 4 a rotates a screw head of the tension adjusting screw 3 (for example, − (minus) shape). A driver 4 (-type) is provided. The driver 4 is disposed such that its axis is along the direction toward the rotation center of the bobbin case 13. The driver 4 is provided at a chuck 5b attached to a rotating shaft 5a of a pulse motor 5 as a rotation driving means for rotating the driver 4 about an axis at a base end thereof.
Here, the engagement position where the driver 4 engages with the tension adjusting screw 3 is on the axis O of the inner hook 12 within a range of 15 ° to 50 ° with respect to the vertical line X orthogonal to the axis O of the inner hook 12. It is preferable that it exists on the straight line Y which cross | intersects. That is, the tension adjusting screw 3 exists in a region R sandwiched between a straight line L1 that forms an angle of 15 ° with respect to the vertical line X and a straight line L2 that forms an angle of 50 ° with respect to the vertical line X. Just do it. This is arranged so as not to come into contact with other peripheral components when the driver 4 or the like is moved.

The pulse motor 5 can rotate the tension adjusting screw 3 by rotating the driver 4 when the tip portion 4 a of the driver 4 is engaged with the screw head of the tension adjusting screw 3. The pulse motor 5 is connected at its base end to a piston 6a of an air cylinder 6 as a moving means for moving the pulse motor 5 along the axis. The air cylinder 6 moves the driver 4 and the pulse motor 5 so that the front end portion 4a of the driver 4 can advance and retract to an engagement position where the tip 4a engages with the tension adjusting screw 3 and a standby position separated from the engagement position. It is moved along the axis. The air cylinder body is fixed to the sewing machine frame.
A frame 7 fixed to the pulse motor 5 is provided around the pulse motor 5. Before the driver 4 approaches and engages with the tension adjusting screw 3, the frame body 7 abuts on at least one of the inner hook 12 and the bobbin case 13 and at least one of the inner hook 12 and the bobbin case 13. An elastic member 8 is provided as a pressing mechanism that presses down in the rotation direction.
The elastic member 8 moves so as to be interlocked with the driver 4 and the pulse motor 5 by the air cylinder 6. Then, before the driver 4 approaches and engages the tension adjusting screw 3, the driver 4 abuts on the inner hook 12 to rotate the inner hook 12 in one rotation direction (for example, counterclockwise direction indicated by arrow A). Energize to.

The elastic member 8 is formed of an elastic metal spring material or the like. The elastic member 8 is formed so as to extend along the axial direction of the driver 4 and the pulse motor 5, and is fixed to the frame body 7. Since the elastic member 8 is provided on the frame body 7, the elastic member 8 moves toward a position eccentric from the axis of the driver 4, that is, in a direction shifted from the center of the bobbin case 13. The elastic member 8 moves so as to be able to advance and retreat between a position where the tip 8a abuts against the inner hook 12 and a position separated from this position.
The distal end portion 8 a of the elastic member 8 is curved so as to be deflected to the outside of the hook 10. The tip 8a of the elastic member 8 urges the inner hook 12 to rotate about its axis (counterclockwise) when it contacts the inner hook 12. Further, the distal end portion 8 a of the elastic member 8 is formed so as to protrude to the shuttle 10 side from the distal end portion 4 a of the driver 4. The distal end portion 8 a of the elastic member 8 is formed so as to contact the inner hook 12 before the driver 4 engages with the tension adjusting screw 3.
The elastic member 8 is formed and disposed so as to contact the side surface of the inner hook 12 when the hook 10 advances to the hook 10, but may be formed so as to contact the bobbin case 13. And the bobbin case 13 may be formed so as to contact both.

<How to adjust the bobbin thread tension>
Next, a method for adjusting the lower thread tension by the lower thread tension adjusting device 1 will be described.
As shown in FIG. 3A, when adjusting the tension of the lower thread T, the air cylinder 6 is driven, and the driver 4, the pulse motor 5, and the elastic member 8 are brought closer to the hook 10. Eventually, the elastic member 8 contacts the outer periphery of the inner hook 12 before the driver 4 contacts the tension adjusting screw 3.
When the elastic member 8 comes into contact with the outer periphery of the inner hook 12, as shown in FIG. 3B, the elastic member 8 is curved so that the tip end portion 8 a deviates outward. Bend. Then, the inner hook 12 is urged to rotate in the direction of arrow A in FIG.
Then, the inner hook 12 is prevented from rattling by one wall portion of the recess 12a coming into contact with the protrusion 14a by the urging force of the arrow A, and the tension adjusting screw 3 of the bobbin case 13 attached to the inner hook 12 is prevented. The position of is also fixed.
After that, as shown in FIG. 3C, the driver 4 is engaged with the screw head of the tension adjusting screw 3 so that the pulse motor 5 is driven in a state where the driver 4 is engaged with the screw head of the tension adjusting screw 3. And the driver 4 is rotated. Here, when the tension adjusting screw 3 is rotated so as to be screwed into the bobbin case 13, the tension applying plate 2 is pressed against the bobbin case 13 and the tension applied to the lower thread T can be increased. On the other hand, when the tension adjusting screw 3 is rotated so as to be removed from the bobbin case 13, the tension applying plate 2 is separated from the bobbin case 13, and the tension applied to the lower thread T can be reduced. At this time, since the inner hook 12 is urged by the elastic member 8 and is pressed against the inner hook retainer 14, rattling is suppressed and the bobbin thread tension can be adjusted accurately.
The driver 4 has its tip 4a engaged with the tension adjusting screw 3 of the inner hook 12 positioned by being urged by the elastic member 8 when the air cylinder 6 is driven to protrude. It is assumed that the position is adjusted in advance with respect to the shuttle 10.

<Effect>
Thus, according to the lower thread tension adjusting device 1, the driver 4 is brought close to the tension adjusting screw 3 by the air cylinder 6 to be engaged, and then the driver 4 is rotated by the pulse motor 5, thereby The clearance with the outer peripheral surface of the bobbin case 13 can be adjusted. Therefore, the tension applied to the lower thread T can be adjusted.
Here, the lower thread tension adjusting device 1 is provided with an elastic member 8, which is moved together with the driver 4 by the air cylinder 6, and the driver 4 approaches and engages with the tension adjusting screw 3. Before, it abuts against the inner hook 12 and urges the inner hook 12 to rotate about its axis.
Thereby, even if the inner hook 12 may rattle when the outer hook 11 rotates, the inner hook 12 is positioned at a predetermined position because it is biased by the elastic member 8. Therefore, the driver 4 can be easily and reliably engaged with the tension adjusting screw 3 with a simple configuration in which the elastic member 8 is provided, and the tension of the lower thread T can be adjusted.
As shown in FIG. 12, the engaging position where the engaging portion 4 engages with the tension adjusting screw 3 is within a range of 15 ° to 50 ° with respect to the vertical line X perpendicular to the axis O of the inner hook 12. And on the straight line Y intersecting on the axis O of the inner hook 12. Therefore, the tension adjusting screw 3 is sandwiched in a range where the lower end angle of the outer hook spring 11b when the outer hook 11 is stopped is not in contact with the feed arm 30 that moves the feed dog 32, and the lower thread tension adjusting device. 1 can advance and retreat.
Therefore, by setting the lower thread tension adjusting device 1 in the range of 15 ° to 50 ° described above, a general sewing machine or a shuttle can be used, and the cost can be reduced.

[Embodiment 2]
Next, Embodiment 2 of the present invention will be described. The difference between the second embodiment and the first embodiment is the pressing mechanism of the lower thread tension adjusting device. Therefore, the pressing mechanism and its operation will be mainly described, and the same components as those in the first embodiment are the same. The reference numerals are attached and the description is omitted.
<Configuration of bobbin thread tension adjusting device>
As shown in FIG. 4, the pressing mechanism of the lower thread tension adjusting device 50 according to the second embodiment includes an operation restricting member 20.
The movement restricting member 20 includes a fixing portion 21 provided on the frame body 7, a spring 22 as an elastic member connected to the tip of the fixing portion 21, a contact portion 23 connected to the tip of the spring 22, have. The fixed portion 21 and the contact portion 23 are formed of a material that is not elastically deformed by the pressing force of the air cylinder 6 against the inner hook 12. The motion regulating member 20 is formed so as to extend along the axial direction of the driver 4 and the pulse motor 5. When the spring 22 expands and contracts in the same direction, the contact portion 23 moves in a position deviated from the axis of the driver 4, that is, in a direction shifted from the center of the bobbin case 13. The front end portion 23 a of the contact portion 23 is formed so as to protrude toward the shuttle 10 side from the front end portion 4 a of the driver 4. The front end portion 23 a of the contact portion 23 is formed so as to contact the inner hook 12 before the driver 4 engages with the tension adjusting screw 3.

<How to adjust the bobbin thread tension>
Next, a method for adjusting the lower thread tension by the lower thread tension adjusting device 50 will be described.
As shown in FIG. 4A, when adjusting the tension of the lower thread T, the air cylinder 6 is driven to bring the driver 4 and the operation restricting member 20 closer to the hook 10. Eventually, the contact portion 23 contacts the outer periphery of the inner hook 12 before the driver 4 contacts the tension adjusting screw 3.
When the abutting portion 23 abuts on the outer periphery of the inner hook 12, as shown in FIG. 4B, the movement of the abutting portion 23 is blocked by the inner hook 12, and the spring 22 is contracted by the reaction force. The inner hook 12 is urged to rotate in the direction of arrow B in FIG. 4 by the elastic force when the spring 22 contracts.
Then, the inner hook 12 is prevented from rattling because one wall portion of the recess 12a is brought into contact with the protrusion 14a by the urging force of the arrow B. And the position of the tension adjusting screw 3 of the bobbin case 13 attached to the inner hook 12 is also fixed.

Thereafter, as shown in FIG. 4C, the driver 4 is engaged with the screw head of the tension adjusting screw 3 so that the pulse motor 5 is driven with the driver 4 engaged with the screw head of the tension adjusting screw 3. And the driver 4 is rotated. Here, when the tension adjusting screw 3 is rotated so as to be screwed into the bobbin case 13, the tension applying plate 2 is pressed against the bobbin case 13. Thereby, the tension | tensile_strength provided to the bobbin thread T can be increased. On the other hand, when the tension adjusting screw 3 is rotated so as to be removed from the bobbin case 13, the tension applying plate 2 is separated from the bobbin case 13. Thereby, the tension applied to the lower thread T can be reduced. At this time, the inner hook 12 is urged by the spring 22 connected to the proximal end side of the abutting portion 23 and is pressed against the inner hook retainer 14, so that the rattling is suppressed and the adjustment of the lower thread tension is accurately performed. Can be done.
In this case, the inner hook 12 may be urged by using air pressure or magnetic force instead of using the elastic force of the spring 22.

[Embodiment 3]
Next, a third embodiment of the present invention will be described. The third embodiment is different from the first embodiment in the presser mechanism of the lower thread tension adjusting device. Therefore, the presser mechanism and its operation are mainly described, and the same components as those in the first embodiment are the same. The reference numerals are attached and the description is omitted.
<Configuration of bobbin thread tension adjusting device>
As shown in FIGS. 5 to 7, the lower thread tension adjusting device 100 includes a frame body 7 fixed to the pulse motor 5 around the pulse motor 5. Before the driver 4 approaches and engages with the tension adjusting screw 3, the frame body 7 abuts both the inner hook 12 and the bobbin case 13 to bring both the inner hook 12 and the bobbin case 13 in the rotational direction. An elastic member 81 is provided as a pressing mechanism that presses down.

  The elastic member 81 is moved by the air cylinder 6 so as to be interlocked with the driver 4 and the pulse motor 5. As shown in FIGS. 6 and 7, before the driver 4 approaches and engages the tension adjusting screw 3, both the inner hook 12 and the bobbin case 13 are brought into contact with each other to rotate the inner hook 12 and the bobbin case 13. The inner hook 12 is urged to rotate in the counterclockwise direction indicated by the arrow C and the bobbin case 13 clockwise as indicated by the arrow D.

  The elastic member 81 is formed of an elastic metal spring material or the like. The elastic member 81 is formed so as to extend along the axial direction of the driver 4 and the pulse motor 5, and is fixed to the frame body 7. Since the elastic member 8 is provided on the frame body 7, the elastic member 8 moves toward a position eccentric from the axis of the driver 4, that is, in a direction shifted from the center of the bobbin case 13. The elastic member 81 moves so as to be able to advance and retreat between a position where the tip 81a abuts against the inner hook 12 and the bobbin case 13 and a position separated from this position.

  The distal end portion 81 a of the elastic member 81 is curved so as to be deviated to the outside of the hook 10. The elastic member 81 rotates the inner hook 12 about its axis (counterclockwise: direction C in FIGS. 5 to 7) when the tip 81 a contacts the inner hook 12 and the bobbin case 13. Energize. The elastic member 81 is attached so as to rotate the bobbin case 13 about the axis (clockwise: direction D in FIGS. 5 to 7) when the tip 81 a abuts against the inner hook 12 and the bobbin case 13. Rush. In other words, the elastic member 81 is formed so that the tip end portion 81 a can be brought into contact with both the inner hook 12 and the bobbin case 13 at a position sandwiched between the side face of the inner hook 12 and the side face of the bobbin case 13.

The distal end portion 81 a of the elastic member 81 is formed so as to protrude from the distal end portion 4 a of the driver 4 to the shuttle 10 side. The elastic member 81 is formed so as to bend in the vicinity of the distal end portion 81 a, and the bent portion comes into contact with the inner hook 12 and the bobbin case 13.
Thus, by forming the elastic member 81 so as to contact both the inner hook 12 and the bobbin case 13, both the inner hook 12 and the bobbin case 13 can be urged and pressed.

<How to adjust the bobbin thread tension>
Next, a method for adjusting the lower thread tension by the lower thread tension adjusting device 100 will be described.
As shown in FIG. 5, when adjusting the tension of the lower thread T, the air cylinder 6 is driven to bring the driver 4, the pulse motor 5, and the elastic member 81 closer to the hook 10. Eventually, as shown in FIG. 6, the elastic member 81 contacts the outer peripheral surfaces of the inner hook 12 and the bobbin case 13 before the driver 4 contacts the tension adjusting screw 3.

  When the elastic member 81 comes into contact with the outer periphery of the inner hook 12 and the bobbin case 13, as shown in FIG. 6, the elastic member 81 is curved so that the distal end portion 81 a deviates outward. It bends away from the bobbin case 13. Then, the inner hook 12 is urged to rotate in the direction of arrow C in FIGS. 6 and 7 by the elastic force when bent, and the bobbin case 13 is rotated in the direction of arrow D in FIGS. Energize. This is because the contact position between the elastic member 81 and the inner hook 12 is on the right side of the elastic member 81, and the contact position between the elastic member 81 and the bobbin case 13 is on the left side of the elastic member 81.

Then, the inner hook 12 is prevented from rattling because one wall portion of the recess 12a abuts on the protrusion 14a by the urging force in the direction of arrow C. On the other hand, the bobbin case 13 is prevented from rattling in the inner hook 12 by the urging force in the direction of arrow D.
Thereafter, since the driver 4 is engaged with the screw head of the tension adjusting screw 3, the pulse motor 5 is driven in a state where the driver 4 is engaged with the screw head of the tension adjusting screw 3, and the driver 4 is rotated. Here, when the tension adjusting screw 3 is rotated so as to be screwed into the bobbin case 13, the tension applying plate 2 is pressed against the bobbin case 13 and the tension applied to the lower thread T can be increased. On the other hand, when the tension adjusting screw 3 is rotated so as to be removed from the bobbin case 13, the tension applying plate 2 is separated from the bobbin case 13, and the tension applied to the lower thread T can be reduced.
At this time, since the inner hook 12 is urged by the elastic member 81 and pressed against the inner hook presser 14, the rattling is suppressed and the bobbin thread tension can be adjusted accurately. Further, since the bobbin case 13 is urged by the elastic member 81 and pressed against the inner hook 12, rattling is suppressed and the bobbin thread tension can be adjusted accurately.

<Effect>
Thus, according to the bobbin thread tension adjusting device 100, the driver 4 is brought close to and engaged with the tension adjusting screw 3 by the air cylinder 6, and then the driver 4 is rotated by the pulse motor 5. Thereby, the clearance gap between the tension | tensile_strength provision board 2 and the outer peripheral surface of the bobbin case 13 can be adjusted, and the tension | tensile_strength provided to the bobbin thread T can be adjusted.
Here, the elastic member 81 moves together with the driver 4 by the air cylinder 6, and comes into contact with the inner hook 12 and the bobbin case 13 before the driver 4 approaches and engages with the tension adjusting screw 3. The case 13 is urged to rotate about the axis.
Thereby, even if the inner hook 12 may rattle during rotation of the outer hook 11, the inner hook 12 is positioned at a predetermined position because it is biased by the elastic member 81. Further, even if the bobbin case 13 accommodated in the inner hook 12 may rattle, the bobbin case 13 is positioned at a predetermined position because it is urged by the elastic member 81.
Therefore, the driver 4 can be easily engaged with the tension adjusting screw 3 with a simple configuration of providing the elastic member 81, and the tension of the lower thread T can be adjusted.

[Embodiment 4]
Next, a fourth embodiment of the present invention will be described. The fourth embodiment is different from the first embodiment in the presser mechanism of the lower thread tension adjusting device. Therefore, the presser mechanism and its operation are mainly described, and the same components as those in the first embodiment are the same. The reference numerals are attached and the description is omitted.
<Configuration of bobbin thread tension adjusting device>
As shown in FIGS. 8 to 11, the lower thread tension adjusting device 200 includes a frame 7 fixed to the pulse motor 5 around the pulse motor 5. The pulse motor 5 is connected to the piston of the air cylinder 6. The main body of the air cylinder 6 is fixed to the sewing machine frame F. Further, before the driver 4 approaches and engages with the tension adjusting screw 3, the sewing machine frame F abuts both the inner hook 12 and the bobbin case 13 to rotate both the inner hook 12 and the bobbin case 13 in the rotational direction. A cylinder device 90 is provided as a pressing mechanism for pressing toward the front.

As shown in FIG. 8, the cylinder device 90 is fixed to the sewing machine frame F with nuts or the like. The cylinder device 90 is constituted by, for example, an air cylinder. The cylinder device 90 includes a cylinder 91 that is fixed to the sewing machine frame F, a piston rod 92 that is slidably provided in the cylinder 91, has a tip that extends outward from the cylinder 91 and retracts into the cylinder 91, It has.
In the cylinder device 90, a piston rod 92 is provided so as to be reciprocally movable linearly, and is disposed so as to contact the side surface of the inner hook 12 and the side surface of the bobbin case 13 on the movement path of the piston rod 92.
An abutting portion 92 a that abuts against the side surface of the inner hook 12 and the side surface of the bobbin case 13 is provided at the tip of the piston rod 92. The contact portion 92a is formed of, for example, a cap member made of a material such as rubber or resin that covers the tip of the piston rod 92.

The cylinder device 90 is driven to move in conjunction with the driver 4 and the pulse motor 5 by the air cylinder 6 to move the piston rod 92. That is, the air cylinder 6 and the cylinder device 90 are controlled by a single control device (not shown). Note that the cylinder device 90 and the air cylinder 6 do not necessarily have to be controlled in synchronism with one control device, and can be controlled separately.
The driving of the cylinder device 90 is controlled so that the piston rod 92 moves forward as the driver 4 moves forward, and the piston rod 92 moves backward as the driver 4 moves backward.

  In the drive control of the cylinder device 90, the abutting portion 92a provided on the piston rod 92 abuts both the inner hook 12 and the bobbin case 13 before the driver 4 approaches and engages the tension adjusting screw 3. Thus, the inner hook 12 and the bobbin case 13 are urged so as to rotate in the rotation direction (for example, the counterclockwise direction indicated by the arrow E and the bobbin case 13 indicated by the arrow G).

  The piston rod 92 of the cylinder device 90 reciprocates in a direction deviating from the center of the bobbin case 13. The piston rod 92 moves so as to be able to advance and retreat between a position where the abutting portion 92a at the tip thereof abuts the inner hook 12 and the bobbin case 13 and a position separated from this position.

  The cylinder device 90 is attached so as to rotate the inner hook 12 about its axis (counterclockwise: direction E in FIGS. 8 to 11) when the abutting portion 92a comes into contact with the inner hook 12 and the bobbin case 13. Rush. Further, the cylinder device 90 rotates the bobbin case 13 about the axis (clockwise: G direction in FIGS. 8 to 11) when the contact portion 92 a contacts the inner hook 12 and the bobbin case 13. Energize. That is, the cylinder device 90 is disposed so that the abutting portion 92 a can abut against both the inner hook 12 and the bobbin case 13 at a position sandwiched between the side surface of the inner hook 12 and the side surface of the bobbin case 13.

The abutting portion 92 a of the cylinder device 90 is disposed so as to protrude toward the hook 10 side from the tip end portion 4 a of the driver 4, and before the driver 4 engages with the tension adjusting screw 3, the abutting portion 92 a is in the middle. It is formed so as to contact the shuttle 12 and the bobbin case 13. Even if the abutting portion 92 a does not protrude toward the hook 10 side from the tip end portion 4 a of the driver 4, the timing of starting the movement of the piston rod 92 may be earlier than that of the driver 4.
Thus, by forming the abutting portion 92a so as to abut both the inner hook 12 and the bobbin case 13, both the inner hook 12 and the bobbin case 13 can be urged and pressed.

<How to adjust the bobbin thread tension>
Next, a method for adjusting the lower thread tension by the lower thread tension adjusting device 200 will be described.
As shown in FIG. 8, when adjusting the tension of the lower thread T, the air cylinder 6 and the cylinder device 90 are driven by the control device, and the driver 4, the pulse motor 5, and the piston rod 92 are brought closer to the hook 10. Go. 9, the contact portion 92 a provided at the tip of the piston rod 92 contacts the outer periphery of the inner hook 12 and the bobbin case 13 before the driver 4 contacts the tension adjusting screw 3.

  When the contact portion 92a contacts the outer periphery of the inner hook 12 and the bobbin case 13, as shown in FIGS. 9 and 10, the contact portion 92a rotates the inner hook 12 in the direction of arrow E in FIGS. The bobbin case 13 is pressed so as to rotate in the direction of arrow G in FIGS. This is because the contact position of the contact portion 92a and the inner hook 12 is on the right side of the paper surface of FIGS. 9 and 10 with respect to the axis of the contact portion 92a, and the contact portion 92a and the bobbin case 13 are in contact with each other. This is because the contact position is on the left side of the paper surface of FIGS. 9 and 10 with respect to the axis of the contact portion 92a.

Then, the inner hook 12 is prevented from rattling because one wall portion of the recess 12a comes into contact with the projection 14a by the pressing force in the direction of arrow E. On the other hand, the bobbin case 13 is prevented from rattling in the inner hook 12 by the pressing force in the arrow G direction.
Thereafter, as shown in FIG. 11, the driver 4 is engaged with the screw head of the tension adjusting screw 3, so that the pulse motor 5 is driven in a state where the driver 4 is engaged with the screw head of the tension adjusting screw 3. Rotate 4 Here, when the tension adjusting screw 3 is rotated so as to be screwed into the bobbin case 13, the tension applying plate 2 is pressed against the bobbin case 13 and the tension applied to the lower thread T can be increased. On the other hand, when the tension adjusting screw 3 is rotated so as to be removed from the bobbin case 13, the tension applying plate 2 is separated from the bobbin case 13, and the tension applied to the lower thread T can be reduced.

  At this time, since the inner hook 12 is pressed by the contact portion 92a and pressed against the inner hook presser 14, the rattling is suppressed and the bobbin thread tension can be adjusted accurately. Further, since the bobbin case 13 is pressed by the abutting portion 92a and pressed against the inner hook 12, rattling is suppressed and the bobbin thread tension can be adjusted accurately.

<Effect>
Thus, according to the lower thread tension adjusting device 200, the driver 4 is brought close to and engaged with the tension adjusting screw 3 by the air cylinder 6, and then the driver 4 is rotated by the pulse motor 5. Thereby, the clearance gap between the tension | tensile_strength provision board 2 and the outer peripheral surface of the bobbin case 13 can be adjusted, and the tension | tensile_strength provided to the bobbin thread T can be adjusted.
Here, the abutting portion 92 a advances by driving the cylinder device 90, and the driver 4 advances by driving the air cylinder 6. Then, before the driver 4 approaches and engages the tension adjusting screw 3, the contact portion 92 a contacts the inner hook 12 and the bobbin case 13 to rotate the inner hook 12 and the bobbin case 13 about the axis. Is pressed by the air pressure in the cylinder 91.
Thereby, even if the inner hook 12 may rattle when the outer hook 11 rotates, the inner hook 12 is positioned at a predetermined position because it is pressed by the contact portion 92a. Even if the bobbin case 13 housed in the inner hook 12 may rattle, the bobbin case 13 is positioned at a predetermined position because it is pressed by the contact portion 92a.
Therefore, the driver 4 can be easily and reliably engaged with the tension adjusting screw 3 with a simple configuration in which the cylinder device 90 is provided, and the tension of the lower thread T can be adjusted.

<Others>
The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the drive source is provided separately for the air cylinder 6 that moves the driver 4 toward the tension adjusting screw 3 and the pulse motor 5 that rotates the driver 4. The drive source to be rotated may be shared by one drive source.
In the above embodiment, the inner hook 12 is rotated in the A direction, the C direction, and the E direction and is positioned at a predetermined position by the inner hook press 14, but instead, the inner hook 12 is moved in the above direction. It is also possible to position by rotating in the opposite direction.

The figure which shows a hook and a bobbin thread tension adjusting device. (A) is sectional drawing of a shuttle, (b) is a figure which shows the structure of a bobbin case and a tension | tensile_strength provision board. FIG. 3 is a diagram illustrating a state of the lower thread tension adjusting device when adjusting the lower thread tension in the first embodiment. The figure which shows the state of the lower thread tension adjustment apparatus at the time of lower thread tension adjustment in Embodiment 2. FIG. The figure which shows the state before the movement start of the driver and elastic member at the time of tension | tensile_strength adjustment of the bobbin thread in Embodiment 3. FIG. The figure which shows the state during the movement of the driver and elastic member at the time of tension adjustment of the bobbin thread in Embodiment 3. FIG. The enlarged view which shows the state which the elastic member in Embodiment 3 is contact | abutting to the inner hook and the bobbin case. The figure which shows the state before the movement start of the driver and elastic member at the time of tension adjustment of the bobbin thread in Embodiment 4. The figure which shows the state during the movement of the driver and elastic member at the time of tension adjustment of the bobbin thread in Embodiment 4. The enlarged view which shows the state which the contact part of the cylinder apparatus in Embodiment 4 is contact | abutting to the inner hook and the bobbin case. The figure which shows the state after completion | finish of a movement of the driver and elastic member at the time of tension adjustment of the bobbin thread in Embodiment 4. The figure explaining the range of the engagement position where a driver engages with a tension adjustment screw.

Explanation of symbols

1 Lower thread tension adjusting device 2 Tension applying plate (lower thread tension applying part)
3 Tension adjusting screw 4 Driver (engagement part)
5 Pulse motor (rotational drive means)
6 Air cylinder (moving means)
8 Elastic member (pressing mechanism)
10 Hook 11 Outer Hook 12 Middle Hook 13 Bobbin Case 15 Bobbin 81 Elastic Member (Pressing Mechanism)
90 Cylinder device (pressing mechanism)
91 Cylinder 92 Piston rod 92a Contact part T Lower thread

Claims (4)

Provided on the outer periphery of a bobbin case housed in an inner hook provided rotatably with respect to the outer hook of the sewing machine, and the lower thread fed from the bobbin in the bobbin case is sandwiched between the outer peripheral surface of the bobbin case A lower thread tension applying portion for applying tension to the lower thread;
A tension adjusting screw that attaches the lower thread tension applying portion to the outer peripheral surface of the bobbin case and adjusts the tension that the lower thread tension applying portion applies to the lower thread;
An engagement portion formed to be engageable with the tension adjustment screw so as to rotate the tension adjustment screw;
Moving means for enabling the engagement portion to advance and retreat between an engagement position for engaging the tension adjusting screw and a standby position for isolating from the engagement position;
A lower thread tension adjusting device comprising: a rotation driving unit that rotates the engaging portion when the engaging portion is engaged with the tension adjusting screw;
Before the engaging portion approaches and engages the tension adjusting screw, it abuts on at least one of the inner hook and the bobbin case and turns at least one of the inner hook and the bobbin case in the rotation direction. the pressing hold-down mechanism Te provided,
The pressing mechanism is capable of moving back and forth between a position that abuts on at least one of the inner hook and the bobbin case and a position that is isolated from this position in conjunction with the advance and retreat of the engaging portion by the moving means. A bobbin thread tension adjusting device comprising an elastic member . Provided on the outer periphery of a bobbin case housed in an inner hook provided rotatably with respect to the outer hook of the sewing machine, and the lower thread fed from the bobbin in the bobbin case is sandwiched between the outer peripheral surface of the bobbin case A lower thread tension applying portion for applying tension to the lower thread;
  A tension adjusting screw that attaches the lower thread tension applying portion to the outer peripheral surface of the bobbin case and adjusts the tension that the lower thread tension applying portion applies to the lower thread;
  An engagement portion formed to be engageable with the tension adjustment screw so as to rotate the tension adjustment screw;
  Moving means for enabling the engagement portion to advance and retreat between an engagement position for engaging the tension adjusting screw and a standby position for isolating from the engagement position;
  A lower thread tension adjusting device comprising: a rotation driving unit that rotates the engaging portion when the engaging portion is engaged with the tension adjusting screw;
  Before the engaging portion approaches and engages the tension adjusting screw, it abuts on at least one of the inner hook and the bobbin case and turns at least one of the inner hook and the bobbin case in the rotation direction. Provided with a pressing mechanism
  The pressing mechanism includes a cylinder device having a contact portion at a tip thereof that can advance and retract between a position that contacts at least one of the inner hook and the bobbin case and a position that is isolated from this position. Lower thread tension adjusting device. The bobbin thread tension adjusting device according to claim 2 , wherein the abutting portion is advanced and retracted in conjunction with the advance and retreat of the engaging portion by the moving means. The engagement position at which the engagement portion engages with the tension adjusting screw is a straight line that intersects the axis of the inner hook within a range of 15 ° to 50 ° with respect to a vertical line orthogonal to the axis of the inner hook. The lower thread tension adjusting device according to any one of claims 1 to 3 , wherein the lower thread tension adjusting device is located above.

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