JP2008148831A - Thread tension guide of sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thread tension guide of a sewing machine which surely prevents the rear end part of a thread tension shaft from entering into a thread tension bracket even if a pressing load based on a driving solenoid and a driving shaft is applied to the thread tension shaft via a movable thread tension disk and a fixed thread tension disk, and constantly applying an appropriate tension to a needle thread in sewing. <P>SOLUTION: This thread tension guide of sewing machines is provided with the thread tension bracket 12, the thread tension shaft 13 mounted on the thread tension bracket 12 relatively non-movably in the axial direction, the movable thread tension disk 14 and the fixed thread tension disk 15 mounted at the front end side of the thread tension shaft 13, the driving shaft 20 mounted at the center of the thread tension shaft 13 relatively movably in the axial direction, and the driving solenoid 30 driving the driving shaft 20 forward and adjusting the thread tension via the movable thread tension disk 14. The thread tension shaft 13 is formed with a projection part 13c projecting from the rear end of the thread tension bracket 12 and is fixedly provided with a C-shaped retaining ring 21 lockable to the projection part 13c at the rear end of the thread tension bracket 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thread tension device for a sewing machine, and in particular, even if a movable thread tension plate is pressurized by a drive shaft that is attached to a central portion of a thread tension shaft so as to be relatively movable in the axial direction, the rear end of the thread tension shaft is The present invention relates to one configured to prevent entry into a thread tension table.

  Conventionally, various sewing machines such as a lockstitch sewing machine and a cycle sewing machine have been provided with a thread tension device that applies tension to the upper thread, and not only manually adjusting the tension of the upper thread but also using a drive solenoid. A thread tension device that can automatically adjust the tension of the thread has been put into practical use.

For example, a thread tension device for a sewing machine described in Patent Document 1 includes a thread tension base fixed to a sewing machine frame, a thread tension shaft that is mounted on the thread tension base so as not to be relatively movable in the axial direction, and a thread tension shaft. A press-side thread tension tray (movable thread tension tray) and a pressed-side thread tension tray (fixed thread tension tray) mounted on the front end side portion of the thread and a center portion of the thread tension shaft are mounted so as to be relatively movable in the axial direction. A drive shaft capable of pushing the movable thread tension plate forward and a thread tension solenoid (drive solenoid) for driving the drive shaft in the axial direction are provided. When the drive voltage is supplied to the drive solenoid, the drive shaft is driven forward, the center of the movable thread tension plate is pressed at the tip of the drive shaft, and the fixed thread tension plate is pressed through the movable thread tension plate. Thus, the tension corresponding to the driving force of the drive solenoid is applied to the upper thread between the two thread tension plates.
JP 2005-261629 A

  By the way, at the start of sewing and at the end of sewing, the movable thread tension plate is repeatedly pressed against the fixed thread tension plate by immediately pressing the upper thread between the two thread tension plates or by releasing the press immediately. During sewing, the movable thread tension tray is continuously pressed against the fixed thread tension tray, so that the pressing load acts on the thread tension shaft via the fixed thread tension tray, and eventually the thread tension base of the thread tension shaft. Therefore, due to repeated pressing loads, the mounting portion is loosened or loosened, the thread tension shaft is displaced relative to the thread tension base, and the rear end of the thread tension shaft is the thread. There is a case of entering the tuning stand.

  As described above, when the rear end of the thread tension shaft enters the thread tension table, the position of the fixed thread tension plate is shifted to a position relatively away from the drive solenoid, and the position where the upper thread is pressed accordingly. Therefore, it becomes impossible to apply an appropriate tension to the upper thread, and in order to maintain an appropriate tension, it is necessary to correct the drive voltage supplied to the drive solenoid to be higher than the initial setting value. As a result, when the same upper thread tension is applied between the same type of sewing machines, the value of the drive voltage supplied to the drive solenoid changes for each sewing machine.

An object of the present invention is to provide a rear end portion of the thread tension shaft within the thread tension stand even when a pressing load based on the drive solenoid and the drive shaft acts on the thread tension shaft via the movable thread tension tray and the fixed thread tension tray. A sewing machine that can reliably prevent entry and can always apply appropriate tension to the upper thread during sewing, and can easily remove the thread tension shaft when replacing a movable thread tension plate, etc. It is to provide a thread tension device.

  The thread tension device for a sewing machine according to claim 1 is a thread tension device for a sewing machine that applies tension to an upper thread, and a thread tension base fixed to a sewing machine frame and an axially movable immovable base mounted on the thread tension base. Thread tension shaft, movable thread tension tray and fixed thread tension tray mounted on the front end side portion of the thread tension shaft, and movable thread tension mounted on the central portion of the thread tension shaft so as to be relatively movable in the axial direction. A drive shaft capable of pushing the tray toward the higher thread tension side, and a drive solenoid for driving the drive shaft in the axial direction to adjust the thread tension via the movable thread tension plate; A protruding portion that protrudes from the rear end portion of the thread tension base, and is a restricting member having a diameter larger than that of the thread tension shaft, and can be locked at the rear end portion of the thread tension base. The restriction member is fixedly provided.

When the drive solenoid is activated at the start of sewing, the drive shaft moves in the axial direction, the tip of the drive shaft pushes the movable thread tension plate toward the higher thread tension plate, and the movable thread tension plate is pressed against the fixed thread tension plate. As a result, tension is applied to the upper thread supplied between the two thread tension plates.
By the way, at the time of sewing, the central portion of the movable thread tension plate is continuously pressed by the tip of the drive shaft, and the pressing load acts on the thread tension shaft through the fixed thread tension plate. Since the regulating member fixedly provided on the protruding portion is locked to the rear end portion of the thread tension base, the displacement or movement of the thread tension shaft is reliably regulated. Therefore, it is possible to prevent the rear end of the thread tension shaft from entering the thread tension table.

  A thread tension device for a sewing machine according to a second aspect of the present invention is the sewing machine according to the first aspect, wherein the regulating member is a C-shaped retaining ring having an inner circumferential portion mounted in an annular groove formed in the protruding portion of the thread tension shaft. It is characterized by that.

  According to a third aspect of the thread tension device for a sewing machine of the present invention, in the first aspect of the invention, the regulating member is a pin member that is mounted and fixed in a pin hole formed orthogonal to the axial direction in the protruding portion of the thread tension shaft. It is structured.

  A thread tension device for a sewing machine according to a fourth aspect of the invention is characterized in that, in the invention of the first aspect, the restricting member is constituted by a nut member screwed into a male thread portion of the protruding portion of the thread tension shaft. .

  A thread tension device for a sewing machine according to a fifth aspect of the present invention is the thread tension device for a sewing machine according to the first aspect, wherein a small diameter portion is formed at an end of the protruding portion of the thread tension shaft, and the regulating member is externally fitted to the small diameter portion. And an annular member fixed to the thread tension shaft.

  According to the first aspect of the present invention, the thread tension shaft is formed with a protruding portion that protrudes from the rear end portion of the thread tension base, and the protruding portion is a restricting member having a larger diameter than the thread tension shaft. Since the restricting member that can be locked at the rear end of the tension base is fixedly provided, the pressing load based on the drive solenoid and the drive shaft acts on the thread tension shaft via the movable thread tension tray and the fixed thread tension tray. In addition, the regulating member fixedly provided on the protruding portion of the thread tension shaft is locked to the rear end portion of the thread tension base, so that the displacement or movement of the thread tension shaft is reliably regulated. It is possible to reliably prevent the rear end from entering the thread tension table.

  Therefore, an appropriate tension can always be applied to the upper thread during sewing. In addition, the thread tension shaft can be easily removed when the movable thread tension plate or the like is replaced, and the replacement work of the movable thread tension tray or the like can be simplified.

  According to the invention of claim 2, since the regulating member is constituted by a C-shaped retaining ring having an inner peripheral portion mounted in an annular groove formed in the protruding portion of the thread tension shaft, the configuration of the thread tension device is simple. The manufacturing cost can be reduced, and the thread tension shaft can be easily assembled and removed.

  According to the invention of claim 3, since the restricting member is composed of a pin member mounted and fixed in a pin hole formed orthogonal to the axial direction at the protruding portion of the thread tension shaft, the configuration of the thread tension device Can be simplified and the production cost can be reduced.

  According to the invention of claim 4, since the restricting member is constituted by the nut member screwed into the male threaded portion of the protruding portion of the thread tension shaft, the restricting member can be firmly fixed to the protruding portion. The regulating member can be reliably locked at the rear end of the thread tension base.

  According to the invention of claim 5, a small-diameter portion is formed at the end portion of the protruding portion of the thread tension shaft, and the restricting member is configured by an annular member that is externally fitted to the small-diameter portion and is fixed to the thread tension shaft by the fastening member. Therefore, the restricting member can be firmly fixed to the protruding portion, and the restricting member can be reliably locked at the rear end portion of the thread tension base.

  The thread tension device of the sewing machine according to the present invention includes a thread tension base fixed to a sewing machine frame, a thread tension shaft that is mounted on the thread tension base so as not to be relatively movable in the axial direction, and a front end side portion of the thread tension shaft. A movable thread tension plate and a fixed thread tension tray, a drive shaft that is attached to the central portion of the thread tension shaft so as to be relatively movable in the axial direction, and that can move the movable thread tension plate toward the higher tension side, and a drive shaft. A drive solenoid for adjusting the thread tension through the movable thread tension plate by driving in the axial direction, and forming a protruding portion protruding from the rear end portion of the thread tension base on the thread tension shaft; A restriction member that is larger in diameter than the thread tension shaft and that can be locked at the rear end of the thread tension base is fixedly provided on the protruding portion.

Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the lockstitch sewing machine 1 includes a bed portion 2 that is partially placed on the work table T and that is mostly accommodated below the work table T, and a right end portion of the bed portion 2. A leg column part 3 rising upward, an arm part 4 extending leftward from the upper end part of the leg column part 3 and facing the bed part 2 are provided. The bed portion 3 is provided with a needle plate 5.

  The arm portion 4 has a needle bar driving mechanism for driving the needle bar 6 having the sewing needle 7 up and down with a driving force of a sewing machine motor (not shown), and a scale drive for driving the balance 8 for lifting the upper thread 9 up and down. A mechanism, a thread tension device 10 and the like are provided. Here, since the needle bar drive mechanism and the balance drive mechanism are known techniques, detailed description thereof is omitted here.

Next, the thread tension device 10 for adjusting the tension of the upper thread 9 in the middle of the upper thread supply path from the upper thread supply source through the balance 8 to the sewing needle 7 will be described.
As shown in FIGS. 1 and 2, the thread tension device 10 is provided on the arm portion 4 of the sewing machine frame, and this thread tension device 10 is provided on the front frame 4 a of the arm portion 4. A mechanism 11 and a drive solenoid 30 provided on the rear frame 4b of the arm portion 4 are provided.

  As shown in FIGS. 2 to 4, the thread tension mechanism 11 includes a thread tension shaft 13 that is mounted on the thread tension base 12 so as not to be relatively movable in the axial direction, and a movable that is mounted on a front end side portion of the thread tension shaft 13. A thread tension tray 14 and a fixed thread tension tray 15 and a drive shaft 20 mounted on the center of the thread tension shaft 13 so as to be relatively movable in the axial direction are provided.

  A forward holding cylindrical holding hole 4c is formed in the front frame 4a of the arm part 4, and a screw hole 4d is formed in the front frame 4a. The thread tension base 12 is mounted in the holding hole 4c, and the thread tension base 12 is fixed to the front frame 4a by a set screw 16 inserted into the screw hole 4d and screwed. When the set screw 16 is screwed when the thread tension base 12 is fixed, the tip surface of the set screw 16 presses the bottom surface of the annular groove 12d formed in the thread tension base 12 over the entire circumference.

  A slit groove 13 b is formed in the front portion of the thread tension shaft 13, and a male screw is formed on the outer peripheral surface of the front portion of the thread tension shaft 13. A circular insertion hole 15a is formed in the central portion of the fixed thread tension tray 15, and a pair of crescent shaped insertions having a bridging portion 14b introduced into the slit groove 13b in the central portion of the movable thread tension tray 14. A hole 14a is formed.

  A movable thread tension tray 14 and a fixed thread tension tray 15 are sequentially fitted into the front portion of the thread tension shaft 13 through insertion holes 14a and 15a from the front, and are fixed by a fixing nut 18 screwed to the tip of the thread tension shaft 13. The fixed thread tension tray 15 and the movable thread tension tray 14 are positioned. The fixed thread tension tray 15 is supported by the thread tension shaft 13 so as not to move with respect to the movable thread tension tray 14, and the movable thread tension tray 14 moves with respect to the fixed thread tension tray 15 via the drive shaft 20. It has a possible configuration.

  The thread tension shaft 13 is inserted into the bearing hole 12c of the thread tension base 12 and fixed to the thread tension base 12 by a set screw 17 screwed into the screw hole 12b of the thread tension base 12 so as not to be relatively movable. . Inside the thread tension shaft 13, an insertion hole 13 a for inserting the drive shaft 20 so as to be movable in the front-rear direction is formed. The thread take-up spring 19 has a coil spring 19a and a thread hooking portion 19b connected to the outer end of the coil spring 19a. It is accommodated in the hole 12a. This thread take-up spring 19 is prepared in advance with several types having different wire diameters depending on the thickness of the thread to be used, that is, different thread take-up spring forces of the thread hooking portion 19b. Therefore, when sewing, the thread take-up spring 19 suitable for the thread thickness to be used can be exchanged with another one. As will be described later, this attachment / detachment replacement is performed by removing the C-shaped retaining ring 21 that restricts the thread tension shaft 13 with respect to the thread tension base 12 from the thread tension shaft 13 and removing the thread tension shaft 13 from the thread tension base 12. This is done by pulling forward and taking out the set comprising the thread tension shaft 13, the thread take-up spring 19, the movable and fixed thread tension plates 14, 15 and the fixing nut 18 to the outside.

  In addition, a protruding portion 13 c that protrudes rearward from the rear side surface of the thread tension base 12 is formed at the rear end portion of the thread tension base 13 in a state of being inserted into the bearing hole 12 c of the thread tension base 12. The projecting portion 13c is formed with an annular groove 13d cut out over the entire circumference. The annular groove 13d has a C-shaped retaining ring 21 having a diameter larger than that of the drive shaft 20 (this corresponds to a regulating member). Is detachably mounted in a fitting manner. A disc-shaped washer 22 having a larger diameter than the C-shaped retaining ring 21 is fitted and supported on the peripheral surface of the thread tensioning base 12 between the C-shaped retaining ring 21 and the rear side surface of the thread tensioning base 12. The In a state where the C-shaped retaining ring 21 is mounted in the annular groove 13 d of the thread tension base 12, the pressing load based on the drive solenoid 30 and the drive shaft 20 is applied to the thread tension shaft via the movable thread tension tray 14 and the fixed thread tension tray 15. 13, since the C-shaped retaining ring 21 is securely received by the rear end portion of the thread tension base 12 via the washer 22 so as not to move backward, the displacement or movement of the thread tension shaft 13 is ensured. As a result, the rear end of the thread tension shaft 13 is surely prevented from entering the bearing hole 12 c of the thread tension base 12. In this case, since a washer 22 having a diameter larger than that of the C-shaped retaining ring 21 is interposed between the C-shaped retaining ring 21 and the rear side surface of the thread tensioning base 12, the thread tensioning base 12 is based on the pressing load. It is possible to stably receive the reaction force acting on the entire surface of the washer 22. The washer 22 is not always necessary, and even if the C-shaped retaining ring 21 is directly brought into contact with the rear side surface of the thread tension base 12, the reaction force can be reliably received and the restriction can be reliably achieved.

Next, the drive shaft 20 will be described.
As shown in FIGS. 3 to 5, the drive shaft 20 is inserted into the insertion hole 13 a of the thread tension shaft 13 and is mounted so as to be relatively movable in the axial direction within the insertion hole 13 a, and the movable thread tension tray 14 is moved to the front side. It is configured to be able to be pushed to the (thread tension stronger side).

  When the drive shaft 20 moves forward by the driving force of the drive solenoid 30, the tip of the drive shaft 20 comes into contact with the bridging portion 14 b of the movable thread tension plate 14, and the movable thread tension plate 14 faces the fixed thread tension plate 15. To push.

Next, the drive solenoid 30 will be described.
As shown in FIG. 2, the drive solenoid 30 is a general proportional solenoid provided in the rear frame 4b, and when a drive voltage is supplied from a control device (not shown), the output shaft 31 is forward (shaft). The thread tension is adjusted by changing the pressing force of the output shaft 31 against the movable thread tension tray 14 according to the drive voltage (drive current). A bolt hole having a male screw that is screwed into the stroke adjusting bolt 33 is formed in the tip side portion of the output shaft 31.

  A stroke adjustment bolt 33 is screwed into a bolt hole of the output shaft 31 and a fixing nut 33a is fastened to the stroke adjustment bolt 33 so that the protruding amount of the stroke adjustment bolt 33 from the output shaft can be adjusted and set. . An intermediate shaft 32 having a predetermined length is disposed between the stroke adjustment bolt 33 and the drive shaft 20. A portion protruding rearward from the rear frame 4b of the drive solenoid 30 is covered with a protective cover 34 made of synthetic resin, and a circular notch hole is formed at the center of the rear end surface of the protective cover 34. Yes.

Next, the operation and effect of the thread tension device 10 of the sewing machine 1 described above will be described.
When the drive solenoid 30 is actuated at the start of sewing, the drive shaft 20 is driven forward, the movable thread tension tray 14 is pushed forward at the tip of the drive shaft 20, and the movable thread tension tray 14 moves the fixed thread tension tray 15. By pressing, a pinching pressure is generated between the two thread tension plates 14 and 15, and tension is applied to the upper thread 9 supplied during this time.

  At the time of sewing, since the bridging portion 14b at the center of the movable thread tension plate 14 is continuously pressed by the tip of the drive shaft 20, the pressing of the movable thread tension plate 14 against the fixed thread tension tray 15 is maintained, and the upper thread 9 is pressed. Tension is continuously applied. Further, when the supply of the drive voltage (drive current) to the drive solenoid 30 is stopped at the end of sewing, the output shaft 31 is retracted backward (backward in the axial direction), and accordingly, the movable thread tension tray 14 of the drive shaft 20 is retracted. The pressing is released, and the application of tension to the upper thread 9 is released.

  As described above, the movable thread tension tray 14 is repeatedly pressed against the fixed thread tension tray 15 each time sewing is started, and the movable thread tension tray 14 is continuously pressed against the fixed thread tension tray 15 during sewing. The pressing load acts on the thread tension shaft 13 via the fixed thread tension plate 15, and eventually acts on the mounting portion (the bearing hole 12b and the set screw 17) of the thread tension shaft 13 with respect to the thread tension base 12. . However, in a state where the C-shaped retaining ring 21 is mounted in the annular groove 13 d of the thread tension base 12, the pressing load based on the drive solenoid 30 and the drive shaft 20 is threaded via the movable thread tension tray 14 and the fixed thread tension tray 15. Even if it acts on the tension shaft 13, the C-shaped retaining ring 21 is reliably received by the rear end portion of the thread tension base 12 via the washer 22, so that the forward displacement or movement of the thread tension shaft 13 is reliably regulated. Thus, the rear end of the thread tension shaft 13 is surely prevented from entering the bearing hole 12c of the thread tension base 12.

Therefore, it is possible to continuously apply the appropriate initial tension to the upper thread 9 at the time of sewing. Further, depending on the thickness of the thread to be used, when it is desired to replace the thread take-up spring 19 suitable for the other one, or the bridge 14b at the center of the movable thread tension plate 14 is deformed by repeated pressing action, etc. When it is desired to replace the movable thread tension plate 14 with a new one, the thread tension shaft 21 is removed by removing the C-shaped retaining ring 21 from the thread tension shaft 13 and pulling the thread tension shaft 13 forward from the thread tension base 12. 13, a thread take-up spring 19, movable and fixed thread tension plates 14 and 15, a fixing nut 18, etc. are taken out to the outside, and the fixing nut 18 is loosened and removed from the male thread of the thread tension shaft 13. 3, the thread take-up spring 19 and the movable thread tension plate 14 can be easily replaced. After replacement, the C-shaped retaining ring 21 is attached to the ring tension shaft 13 in an annular shape. Groove 13d It can be assembled by mounting.
After this assembling, it is possible to continuously apply an appropriate initial tension to the upper thread 9, and to perform a predetermined thread take-up action corresponding to the replaced thread take-up spring 19.

Next, a modified example in which the above embodiment is partially modified will be described.
1] In the above-described embodiment, as shown in FIG. 6, an opening is formed in the vicinity of the rear end portion of the protruding portion 13 c of the thread tension shaft 13 in a penetrating state in a portion orthogonal to the axial direction and avoiding the insertion hole 13 a. It is also possible to form a pin hole 13e, and fit and fix a pin member 40 as a restricting member having a length considerably longer than the diameter of the thread tension shaft 13 into the pin hole 13e. In this case, the configuration of the thread tension device 10 can be simplified and the production cost can be reduced.

  2] In the above embodiment, as shown in FIG. 7, a small-diameter male screw portion 13f having an insertion hole 13a is formed at the rear end portion of the protruding portion 13c of the thread tension shaft 13, and the male screw portion 13f An annular member 41 (which corresponds to a nut member) as a restricting member having a female screw portion 41a screwed to the male screw portion 13f on the inner peripheral surface and having a diameter considerably larger than the diameter of the thread tension shaft 13. May be screwed together. In this case, the annular member 41 can be firmly fixed to the protruding portion 13 a of the thread tension shaft 13, and the thread tension shaft 13 can be reliably locked at the rear end of the thread tension base 12.

  3] In the above embodiment, as shown in FIG. 8, a set collar 42 as a regulating member having a diameter considerably larger than the diameter of the thread tension shaft 13 is removed from the rear end portion of the protruding portion 13c of the thread tension shaft 13. In the fitted state, the set collar 42 may be fixed to the thread tension shaft 13 by screwing a set screw 42b into the screw hole 42a of the set collar 42.

  4] In the above embodiment, as shown in FIG. 9, a small-diameter portion 13g is formed at the rear end portion of the protruding portion 13c of the thread tension shaft 13, and the small-diameter portion 13g has a male screw portion 13h on its peripheral surface. At the same time, an insertion hole 13a is formed at the center. A hollow annular member 43 as a regulating member having a diameter considerably larger than the diameter of the thread tension shaft 13 is inserted and supported in the small diameter portion 13g. In addition, a nut (fastening member) 44 having a female screw portion 44a screwed to the male screw portion 13h on the inner peripheral surface is screwed to the rear side portion of the small diameter portion 13g. In this case, the annular member 43 can be firmly fixed to the protruding portion 13 c of the thread tension shaft 13.

  5] In the above embodiment, as shown in FIG. 10, a screw hole 13 i is formed in the axial direction at the rear end of the protruding portion 13 c of the thread tension shaft 13, and the diameter is considerably larger than the diameter of the thread tension shaft 13. A bolt 46 formed with an insertion hole 46a through which the drive shaft 20 is inserted at the center is screwed into the screw hole 13i through a hollow annular member 45 serving as a regulating member. It may be fixed to the shaft 13.

  6] In the above embodiment, as shown in FIG. 11, a hollow annular member as a regulating member having a diameter substantially larger than the diameter of the thread tension shaft 13 at the rear end portion of the protruding portion 13c of the thread tension shaft 13 A bolt 48 having a head 48b having a width dimension larger than the diameter of the protruding portion 13c of the thread tension shaft 13 is formed in the center with an insertion hole 48a through which the drive shaft 20 is inserted with the 47 being fitted and held. The annular member 47 may be fixed to the thread tension shaft 13 by screwing into the screw hole 13j of the thread tension shaft 13. 10 to 11, a headed pin is applied in place of the bolts 46 and 48 and a pin hole is formed in place of the screw holes 13i and 13j, and the headed pin is firmly fitted into the pin hole to form an annular shape. It is also possible to fix the members 45 and 47.

  7] In addition, the present invention includes such modifications as long as the present invention can be implemented in a form in which various modifications are added without departing from the spirit of the present invention.

It is a perspective view of the lockstitch sewing machine concerning the example of the present invention. It is a principal part vertical side view of the arm part of a lock stitch sewing machine. It is a disassembled perspective view of a thread tension mechanism. It is a principal part vertical side view of a thread tension mechanism. It is a principal part enlarged side view of a thread tension shaft and a C-shaped retaining ring. It is a principal part expanded side view of the thread tension axis | shaft and regulating member in a modification. It is a principal part expanded side view of the thread tension axis | shaft and regulating member in a modification. It is a principal part expanded side view of the thread tension axis | shaft and regulating member in a modification. It is a principal part expanded side view of the thread tension axis | shaft and regulating member in a modification. It is a principal part expanded side view of the thread tension axis | shaft and regulating member in a modification. It is a principal part expanded side view of the thread tension axis | shaft and regulating member in a modification.

Explanation of symbols

1 sewing machine 10 thread tension device 12 thread tension base 13 thread tension shaft 13c projecting portion 13d annular groove 13e pin hole 13f male threaded portion 13g small diameter portion 14 movable thread tension plate 15 fixed thread tension plate 20 drive shaft 21 C-shaped retaining ring 30 drive solenoid 40 pin member 41 annular member 42 set collar 43 annular member 44 nut 45 annular member 47 annular member

Claims (5)

In the thread tension device of the sewing machine that applies tension to the upper thread,
A thread tension base fixed to the machine frame,
A thread tension shaft mounted on the thread tension base so as not to be relatively movable in the axial direction;
A movable thread tension tray and a fixed thread tension tray mounted on the front end side portion of the thread tension shaft;
A drive shaft that is attached to the central portion of the thread tension shaft so as to be relatively movable in the axial direction, and is capable of pushing the movable thread tension plate to the thread tension stronger side;
A drive solenoid for driving the drive shaft in the axial direction and adjusting the thread tension via a movable thread tension tray;
The thread tension shaft is formed with a protruding portion that protrudes from the rear end portion of the thread tension base, and the protruding portion is a regulating member having a larger diameter than the thread tension shaft, and the rear end portion of the thread tension base The restriction member that can be locked with is fixedly provided,
A thread tension device for a sewing machine characterized by the above.   2. The thread tension device for a sewing machine according to claim 1, wherein the restricting member comprises a C-shaped retaining ring having an inner peripheral portion mounted in an annular groove formed in the protruding portion of the thread tension shaft. .   2. The thread tension of the sewing machine according to claim 1, wherein the restricting member is configured by a pin member that is mounted and fixed in a pin hole that is formed orthogonal to the axial direction at the protruding portion of the thread tension shaft. apparatus.   2. The thread tension device for a sewing machine according to claim 1, wherein the restricting member comprises a nut member screwed into a male thread portion of the protruding portion of the thread tension shaft.   A small-diameter portion is formed at an end of the protruding portion of the thread tension shaft, and the restricting member is formed of an annular member that is externally fitted to the small-diameter portion and is fixed to the thread tension shaft by a fastening member. The thread tension device for a sewing machine according to claim 1.

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