JP2005245557A - 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 allows adjustment of the tension of an upper thread according to the kind or thickness of a sewn object, thickness or elasticity of the thread, stitch, and the like, even if a user has no skill and experience. <P>SOLUTION: An adjusting member 9 of the thread tension guide 1 is turned and operated to increase and reduce the resilient force of a coil spring 7, the resilient force of the coil spring 7 presses the upper thread B held between a pair of thread tension discs 4 and 4, and tension imparted to the upper thread B is adjusted. Distortion of a distortion detector 5, which is caused when the upper thread B held in the pair of thread tension discs 4 and 4 is pressed, is detected by a distortion gauge 5A, and tension imparted to the upper thread B is calculated by a thread tension calculator 10 on the basis of detection information output from the distortion gauge 5A. The tension of the upper thread B, which is calculated by the thread tension calculator 10, is indicated as a tension value of the upper thread by a display device 11 so as to be visually recognized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  This invention adjusts the upper thread tension according to the type and thickness of the material to be sewn, the thickness of the thread, the elasticity of the thread, how to sew, etc., even if there is no skill and experience in sewing work with a sewing machine, for example. The present invention relates to a thread tension adjusting device for a sewing machine that can be used.

  Conventionally, as a method of adjusting the tension applied to the above-described upper thread, for example, the adjustment knob is rotated to increase and decrease the restoring force accumulated in the coil spring, and the pair of threads is recovered by the restoring force of the coil spring. The upper thread sandwiched between the tension plates is pressed to adjust the tension applied to the upper thread, but the amount of rotation of the adjustment knob and the restoring force of the coil spring are not necessarily proportional, depending on the experience and skill level of the operator Since the tension applied to the upper thread is different, it is difficult to adjust to the desired tension, and it is impossible to sew the article to be sewn in substantially the same state under substantially the same conditions.

  As a method for solving the above problem, for example, when the upper thread sandwiched between a pair of tension plates is pressed by a restoring force accumulated in a coil spring, the pressure applied to the tension plate is detected by a pressure sensor, and the pressure is detected. Although there is an upper thread tension adjusting device of the sewing machine disclosed in Patent Document 1 that displays the upper thread tension calculated by the tension calculating means on the display based on the pressure detected by the sensor, the axial pressure applied to the tension plate. Therefore, if the tension plate is tilted due to pinching of the upper thread, the pressure is not evenly applied to the pressure sensor and the pressure value varies, so the exact pressure applied to the upper thread It is difficult to detect and it is difficult to adjust to a desired tension.

JP-A-9-276577.

  In view of the above problems, the present invention detects a strain amount of a strain detection body, which is generated when an upper thread sandwiched between a pair of thread tension plates is pressed, with a strain gauge, and based on detection information output by the strain gauge. By displaying the upper thread tension calculated by the thread tension calculation means on the display means, depending on the type and thickness of the material to be sewn, the thickness of the thread, the elasticity of the thread, the sewing method, etc., even without skill and experience An object of the present invention is to provide a thread tension adjusting device for a sewing machine which can easily and easily adjust the tension of the upper thread.

  The present invention provides a sewing machine that presses an upper thread sandwiched between a pair of thread tension plates by a restoring force of a coil spring that is increased or decreased by a rotating operation of an adjusting member, and variably adjusts a tension applied to the upper thread. A tension detector that is interposed between the thread tension plate and the coil spring, and generates strain according to an increase and decrease in restoring force accumulated in the coil spring, and the strain detector Based on the strain gauge that detects the strain amount of the strain detector that is generated when the upper thread that is mounted and is sandwiched between a pair of thread tension plates is pressed, and the detection information that is output by the strain gauge, Yarn tension adjusting device for a sewing machine comprising yarn tension calculating means for calculating applied tension and display means for displaying the upper thread tension calculated by the yarn tension calculating means as a tension value readable by the human eye It is characterized by being.

  The above-described yarn tension calculating means can be constituted by, for example, a personal computer, a host computer, a control device including a CPU, a ROM, and a RAM. The display means may be a digital or analog display that converts the tension value that can be read by human eyes, such as numbers, letters, and symbols, or a display such as an indicator or a level gauge. Can be configured. In addition, for example, a sound type notification means (for example, a speaker or a buzzer) for notifying by a voice message, volume (large or small), timbre change, etc., for example, lighting, blinking, number of lighting, light brightness, change in emission color, etc. An optical notification means (for example, a light emitting element, a lamp, a lighting device, etc.) can also be used.

  That is, by rotating the adjusting member of the thread tension adjusting device, the restoring force accumulated in the coil spring is increased and decreased, and the restoring force of the coil spring presses the upper thread sandwiched between the pair of thread tension plates. The tension applied to the upper thread is adjusted to be substantially equal to the tension applied to the lower thread. In addition, the strain gauge detects the strain amount of the strain detection body that is generated when the upper thread sandwiched between the pair of thread tension plates is pressed, and is applied to the upper thread based on the detection information output by the strain gauge. The calculated tension of the upper thread is displayed on the display means as a tension value of the upper thread that can be read by human eyes.

  As an embodiment, the strain gauge can be attached to a portion where the strain of the strain detector is likely to generate strain. In addition, the strain detector to which the strain gauge is attached can be formed in a thickness and shape that can easily detect strain generated when the upper thread sandwiched between the pair of thread tension plates is pressed. Further, the strain detection body can be constituted by a ring interposed between the thread tension plate and the coil spring and a support piece formed on the peripheral edge of the ring. That is, the ring can be composed of one or both of a large-diameter ring and a small-diameter ring, and the support piece can be an opposing peripheral edge of the large-diameter ring and the small-diameter ring, an inner peripheral edge of the large-diameter ring, and an outside of the small-diameter ring. It can be formed either on the periphery or on the periphery.

  According to the present invention, the strain gauge detects the strain amount of the strain detection body generated when the upper thread sandwiched between the pair of thread tension plates is pressed, and based on the detection information output by the strain gauge. The upper thread tension calculated by the tension calculating means is displayed on the display means as the upper thread tension value that can be read by the human eye, so even if the thread tension plate is tilted, the distortion amount error that occurs in the strain detector is not detected. Compared with the method of detecting the pressure with the pressure sensor of Patent Document 1, the tension applied to the upper thread can be accurately and reliably calculated, and even if there is no skill and experience, The optimum tension can be adjusted according to the thickness, thread thickness, thread elasticity, sewing method, and the like. In addition, the tension value of the upper thread displayed by the display means is visually confirmed with the human eye, and the tension applied to the upper thread is adjusted, so one or a plurality of threads that are hung on one and a plurality of sewing machines. The work of adjusting the tension of the upper thread to substantially the same value can be performed easily and easily, and the work to be sewn is finished in substantially the same state under substantially the same conditions, so that the quality can be made uniform.

  According to the present invention, it is possible to easily and easily adjust the upper thread tension according to the type and thickness of the sewing object, the thickness of the thread, the elasticity of the thread, the sewing method, etc. The purpose is to detect the amount of strain of the strain detection body that occurs when the upper thread sandwiched between a pair of thread tension plates is pressed with a strain gauge, and with the thread tension calculation means based on the detection information output by the strain gauge This can be achieved by displaying the calculated upper thread tension on the display means.

  An embodiment of the present invention will be described in detail with reference to the drawings.

  The drawing shows a sewing thread tension adjusting device that can be variably adjusted to the tension of the upper thread according to the type and thickness of the item to be sewn, the thickness of the thread, the elasticity of the thread, the sewing method, etc. 1, 2, and 3, the thread tension adjusting device 1 for the sewing machine A includes a bottomed cylindrical main body member 2 that is embedded and fixed on the work side outer surface of the arm Aa that constitutes the sewing machine A. The pair of thread tension plates 4 and 4 and the strain detecting body 5, the spring receiving tray 6, the coil spring 7, the rotation feeling imparting plate 8, and the adjusting member 9 that are attached to the support shaft 3 projecting to the central portion on the opening side of the main body member 2. And a strain detector 5 that detects the amount of strain generated when the upper thread B sandwiched between the pair of thread tension plates 4 and 4 is pressed, and based on detection information output from the strain detector 5. A thread tension calculating device 10 for calculating the tension applied to the upper thread B; Composed of the display device 11 for readably displaying the tension applied to the upper thread B to the human eye.

  Further, the free end of the thread take-up spring 2b wound around the outer peripheral surface of the support shaft 3 inside the opening of the main body member 2 protrudes outside from a notch 2a formed on the outer peripheral surface of the main body member 2, and the thread take-up spring 2b. Appropriate tension is applied to the upper thread B hung on the free end of the thread so that unnecessary slack does not occur. Further, a plurality of yarn tension adjusting devices 1 can be provided on the arm Aa or the main body of the sewing machine A according to the number of the upper threads B hung on the sewing machine A.

  The support shaft 3 protruding toward the opening side of the main body member 2 fixes the base end of the support shaft 3 at the center of the bottom of the main body member 2 and protrudes outward from the opening portion of the main body member 2. A male screw portion 3a to which an adjusting member 9 described later is attached so as to be able to rotate forward and backward is threaded on the outer peripheral surface of the shaft 3 on the protruding side. Further, a groove portion 3b in which the entire length on the protruding side of the support shaft 3 is divided into a substantially bifurcated shape with respect to the axial direction is formed substantially parallel to the substantially axial direction of the support shaft 3.

  The pair of thread tension plates 4 and 4 interposed between the main body member 2 and the strain detector 5 are formed in a substantially disc shape having substantially the same size and shape when viewed from the side, 3 is formed at the center of the thread tension plate 4 so that the thread clamping surfaces of the pair of thread tension plates 4 and 4 face each other and protrude toward the opening of the main body member 2. It is attached to the outer peripheral surface of the support shaft 3 so as to be movable in the axial direction.

  As shown in FIG. 4, the strain detector 5 interposed between the pressing-side thread tension plate 4 and the spring receiving plate 6 is distorted in accordance with the increase and decrease of the restoring force accumulated in the coil spring 7. The large diameter formed of a stainless steel thin plate having a thickness of about 0.05 mm and formed in a size and shape substantially matching the contact surface of the thread tension plate 4 and the spring tray 6 A pair of support pieces 5c and 5c formed on the opposing peripheral edge portion of the large diameter ring 5a and the small diameter ring 5b, the ring 5a and the small diameter ring 5b formed in a size and shape that allows the support shaft 3 to be inserted. A foil-type strain gauge 5A, which is integrally connected in the radial direction and detects the amount of strain generated when the upper thread B sandwiched between the pair of thread tension plates 4 and 4 is pressed, is used as the strain of the strain detector 5. Is attached to one or both support pieces 5c.

  In addition, a part or the whole of the strain detector 5 is formed into a curved shape that is very similar to the thread tension plate 4 or the spring tray 6 or a shape that is substantially flat when viewed from the side surface. It is formed in a thickness and shape in which minute stress distortion generated when the upper thread B sandwiched between the thread tension plates 4 and 4 is pressed is remarkably easy to detect. In addition, the material is not limited to the stainless steel of the embodiment as long as it is a material in which distortion is likely to occur, and other materials can be used. In addition, the thickness of the strain detector 5 can be changed to approximately 0.05 mm or less and above.

  As shown in FIG. 5, the above-described strain gauge 5A has a grid 5Ab meanderingly connected to the grid 5Ab on a substantially central surface of a flexible base 5Aa formed of plastic such as polyimide resin. The gauge leads 5Ac and 5Ac are connected to a bridge circuit 10a (for example, a Wheatstone bridge circuit or the like) constituting the yarn tension calculating device 10 described later. In other words, the minute stress strain of the strain detector 5 generated when the upper thread B sandwiched between the pair of thread tension plates 4 and 4 is pressed is detected by the restoring force and elastic force accumulated in the coil spring 7. The detected information is output to the yarn tension calculating device 10. In the embodiment, the resistance R1 of the bridge circuit 11a is constituted by the strain gauge 5A. However, one or more of the remaining resistances R2, R3, R4 can be constituted by the strain gauge 5A, and strain detection is possible. Accuracy is improved.

  As another method for attaching the strain gauge 5A, for example, as shown in FIG. 6, the strain gauge 5A is attached to one or both support pieces 5c formed on the inner peripheral edge of the large diameter ring 5a constituting the strain detector 5. Alternatively, as shown in FIG. 7, a strain gauge 5A may be attached to one or both support pieces 5c formed on the outer peripheral edge of the small diameter ring 5b. The attachment position and the number of attachments of the strain gauge 5A can be changed as necessary.

  The coil spring 7 loaded between the aforementioned spring tray 6 and the rotation feeling imparting plate 8 has one end side large diameter portion received by the receiving surface of the spring tray 6 and the other end side small diameter portion defined by the rotation feeling imparting plate 8. In addition to being formed in a size and shape to be in contact with the end face, the other end side small diameter portion is bent into a shape that is locked to the groove portion 3b of the support shaft 3 so as not to rotate.

  The rotational feel imparting plate 8 interposed between the coil spring 7 and the adjusting member 9 has a bifurcated hole 8a into which the support shaft 3 is allowed to be inserted at the center of the rotational feel imparting plate 8. And the notch surface 8b engaged with the notch surface 9b of the adjustment member 9 mentioned later is formed in the end surface of this rotation feeling provision board 8 facing the notch surface 9b of the adjustment member 9. As shown in FIG.

  The adjustment member 9 attached to the end portion of the support shaft 3 is formed with a female screw portion 9a into which the male screw portion 3a of the support shaft 3 is screwed in the center portion of the adjustment member 9 in the axial direction. A notch surface 9 b engaged with the notch surface 8 b of the rotation feeling imparting plate 8 is formed on the end surface of the adjusting member 9 facing the notch surface 8 b of the rotation feeling imparting plate 8. In addition, the adjustment member 9 screwed to the male screw portion 3b of the support shaft 3 is provided so as to be able to rotate forward and backward in a direction in which the coil spring 7 is compressed and a direction in which the compression is released.

  The notch surfaces 8b and 9b described above have a substantially triangular shape formed on the notch surfaces 8b and 9b when the adjusting member 9 is rotated in the direction in which the coil spring 7 is compressed and the direction in which the compression is released. Appropriate rotational resistance is imparted by the engagement of the concavo-convex portions, and a notch sound is generated when the concavo-convex portions engage.

  As shown in FIGS. 1 and 8, the above-described yarn tension calculating device 10 uses the restoring force and elastic force accumulated in the coil spring 7 to remove the upper yarn B sandwiched between the pair of thread tension plates 4 and 4. A small strain amount of the strain detecting body 5 generated when pressed is detected by the strain gauge 5A, and based on detection information (resistance value) output from the strain gauge 5A, between the pair of thread tension plates 4 and 4 The display device 11 displays the tension applied to the upper thread B sandwiched between the upper thread B by calculation processing, and displays the calculated upper thread B tension as a tension value of the upper thread B that can be read by human eyes. Output.

  The above-described display device 11 is composed of, for example, a digital or analog display, and can read the tension of the upper thread B output from the yarn tension calculating device 10 with human eyes such as numbers, letters, symbols, and the like. Converted to a proper tension value and displayed. In the embodiment, the display device 11 is attached to the outer surface of the sewing machine A that can be read by human eyes. However, the display device 11 may be attached to a work table (not shown) on which the sewing machine A is installed and other display locations. . In addition, the display device 11 can be configured by a display such as an indicator or a level gauge.

  Further, as another method for replacing the display device 11, for example, a sound notification device such as a speaker or a buzzer, for example, an optical notification device such as a light emitting element, a lamp, or a lighting device is applied to the upper thread B. It is also possible to notify the tension. In other words, when the notification is performed by the sound notification device, the sound pattern information stored in advance according to the tension of the upper thread B is notified by, for example, a voice message, a volume (large or small), a change in timbre, and the like. On the other hand, when the notification is made by the optical notification device, the light pattern information stored in advance according to the tension of the upper thread B is notified by, for example, lighting or flashing, the number of lighting, the luminance of light, the change of the emission color, or the like. In addition, you may alert | report combining the display apparatus 11, a sound-type alerting | reporting apparatus, and multiple optical alerting | reporting apparatuses.

  The illustrated embodiment is configured as described above. Hereinafter, a method for adjusting the thread tension of the upper thread B by the thread tension adjusting device 1 attached to the sewing machine A will be described.

  First, as shown in FIG. 1, before starting the sewing operation, the upper thread B wound around the thread winding portion Af is inserted into the thread hooks Ag, Ag and the balance Ah attached to the arm Aa, and the thread tension adjusting device 1 is inserted. Is sandwiched between a pair of thread tension plates 4 and 4 and hung on the free end of the thread take-up spring 2b and inserted through the needle tip of the sewing needle Ae.

  Next, as shown in FIG. 2, the adjusting member 9 attached to the support shaft 3 of the yarn tension adjusting device 1 is rotated in a direction in which the restoring force accumulated in the coil spring 7 increases and decreases. The upper thread B sandwiched between the pair of thread tension plates 4 and 4 is pressed with the restoring force accumulated in the thread 7, and the tension applied to the upper thread B is applied to the lower thread (not shown). Adjust so that it is approximately equal to the tension.

  Further, as shown in FIG. 8, the strain gauge 5A detects the amount of strain of the strain detector 5 generated when the upper thread B sandwiched between the pair of thread tension plates 4 and 4 is pressed, and the strain gauge The detection information detected at 5A is output to the yarn tension calculating device 10. On the other hand, the yarn tension calculating device 10 calculates the tension applied to the upper thread B based on the detection information output from the strain gauge 5A, and can read the calculated tension of the upper thread B with human eyes. The tension value of the upper thread B is displayed on the display device 11 shown in FIG.

  Further, when the adjustment member 9 is rotated to increase and decrease the restoring force accumulated in the coil spring 7, the strain generated in the strain detector 5 changes, and according to the detection information detected by the strain gauge 5A, Since the tension value of the upper thread B is displayed on the display device 11, the type and thickness of the sewing product C, the thickness of the thread, and the thickness of the thread C are confirmed while visually confirming the tension value of the upper thread B displayed on the display device 11. The tension of the upper thread B can be variably adjusted according to the elasticity of the thread, the sewing method, and the like.

  In the sewing operation, the workpiece C is fed to the needle drop position on the throat plate Ac fixed to the feed base Ab of the sewing machine A, and the feed dog (not shown) is pressed down with the presser foot Ad attached to the arm Aa. The sewing needle Ae is swung in conjunction with the feed movement, and the upper thread B adjusted to the optimum tension is sewn to the sewn portion of the sewing product C and sewn in a desired sewing manner.

  As described above, the strain gauge 5A detects the strain amount of the strain detector 5 that is generated when the upper thread B sandwiched between the pair of thread tension plates 4 and 4 is pressed, and the strain gauge 5A outputs the detection. Since the tension of the upper thread B calculated by the thread tension calculating device 10 based on the information is displayed on the display device 11 as the tension value of the upper thread that can be read by human eyes, even if the thread tension plate 4 is tilted, the tension Compared with the method of detecting the pressure with the pressure sensor of Patent Document 1, the tension applied to the upper thread B can be accurately and reliably calculated, and the skill and experience are small. Even if there is not, it can adjust to the optimal tension according to the kind and thickness of the to-be-sewn product C, the thickness of the thread, the elasticity of the thread, the sewing method, and the like. In addition, since the tension value of the upper thread B displayed on the display device 11 is visually confirmed by the human eye and the tension applied to the upper thread B is adjusted, 1 applied to one and a plurality of sewing machines A The work of adjusting the tension of one or a plurality of upper threads B to substantially the same value can be performed easily and easily, and the workpiece C is sewn and finished in substantially the same state under substantially the same conditions to achieve uniform quality. be able to.

In the correspondence between the configuration of the present invention and the above-described embodiment,
The yarn tension calculating means of this invention corresponds to the yarn tension calculating device 10 of the embodiment,
Similarly, the display means corresponds to the display device 11,
The present invention is not limited to the configuration of the above-described embodiment.

The perspective view which shows the attachment state of a thread | yarn tension adjusting device. FIG. 3 is a longitudinal side view showing the internal structure of the yarn tension adjusting device. The perspective view which shows the expansion | deployment state of a yarn tension adjusting device. The top view which shows the attachment state of a strain gauge. The enlarged plan view which shows a strain gauge. The top view which shows the other attachment state of a strain gauge. The top view which shows the other attachment state of a strain gauge. A bridge circuit showing the circuit configuration of the strain gauge.

Explanation of symbols

DESCRIPTION OF SYMBOLS A ... Sewing machine B ... Upper thread C ... Sewing thing 1 ... Thread tension adjusting device 2 ... Main body member 3 ... Spindle 4 ... Thread tension plate 5 ... Strain detector 5A ... Strain gauge 5a ... Large diameter ring 5b ... Small diameter ring 5c DESCRIPTION OF SYMBOLS ... Supporting piece 6 ... Spring tray 7 ... Coil spring 8 ... Rotation touch provision board 9 ... Adjustment member 10 ... Yarn tension calculation apparatus 11 ... Display apparatus

Claims (4)

Adjusting the thread tension of the sewing machine that presses the upper thread sandwiched between the pair of thread tension plates with the restoring force of the coil spring that is increased or decreased by the rotating operation of the adjusting member, and variably adjusts the tension applied to the upper thread. A device,
A strain detector that is interposed between the thread tension plate and the coil spring, and generates strain according to an increase and decrease in restoring force accumulated in the coil spring;
A strain gauge that is mounted on the strain detector and detects the amount of strain of the strain detector that occurs when the upper thread sandwiched between a pair of thread tension plates is pressed;
Thread tension calculating means for calculating the tension applied to the upper thread based on the detection information output by the strain gauge;
A thread tension adjusting device for a sewing machine, comprising: display means for displaying the tension of the upper thread calculated by the thread tension calculating means as a tension value that can be read by human eyes. 2. The thread tension adjusting device for a sewing machine according to claim 1, wherein the strain gauge is attached to a portion where the strain of the strain detector is likely to generate strain. The strain detection body to which the strain gauge is attached is formed in a thickness and shape that makes it easy to detect significantly the strain that occurs when an upper thread sandwiched between the pair of thread tension plates is pressed. Thread tension adjusting device for sewing machine. The thread tension adjustment of the sewing machine according to claim 1, 2 or 3, wherein the strain detection body is composed of a ring interposed between the thread tension plate and the coil spring and a support piece formed on the peripheral edge of the ring. apparatus.

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