JP2009142368A - Thread tension guide of sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To arbitrarily select the linking/non-linking of a thread tension adjustment mechanism and a thread tension fine adjustment mechanism. <P>SOLUTION: In the thread tension guide 1 of a sewing machine including the thread tension adjustment mechanism 10 for simultaneously adjusting the thread tension of respective threads in the sewing machine for performing sewing using the plurality of threads by the drive of one drive source or a manual operation, the thread tension fine adjustment mechanism 30 for individually and finely adjusting the tension of the respective threads by the manual operation, and a reset mechanism 50 for restoring the tension imparted to the respective threads by the thread tension fine adjustment mechanism to a reference value, the operation of imparting the tension to the respective threads only by the thread tension adjustment mechanism and the operation of restoring the tension of the respective threads by the thread tension fine adjustment mechanism to the reference value by the reset mechanism in linkage with the operation of the thread tension adjustment mechanism when the thread tension adjustment mechanism is operated are alternately performed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thread tension device for a sewing machine that adjusts the tension applied to the thread of the sewing machine.

In order to form a beautiful seam and improve the quality of the sewing product, it is necessary to apply an appropriate tension to the thread. There is a thread tension device that adjusts the tension applied to the thread in order to give an appropriate tension to the thread.
For example, in an overlock sewing machine, since multiple threads are used, it is important to maintain the tension balance of each thread. A thread tension mechanism is provided for each thread, and appropriate tension is simultaneously applied to each thread. There is a thread tension device that can be used (for example, see Patent Document 1).
Some of these thread tension devices are provided with a fine adjustment mechanism for finely adjusting the tension applied to each thread.
The thread tension applied to each thread is first applied with a reference value according to the type of stitches by the thread tension mechanism. The reference value of the thread tension is set to, for example, a value according to a thread often used when sewing a selected seam, a center value of a thread tension range used for the selected seam, or the like.
If the expected stitch quality cannot be obtained with the thread tension reference value, the thread tension is adjusted from the reference value by the fine adjustment mechanism. For this reason, the fine adjustment mechanism is provided so that the reference value of the thread tension can be applied when it is located at the center (origin position) of the adjustment range. Further, since fine adjustment needs to be performed for each yarn, the adjustment can be performed independently of the yarn tension mechanism that applies the yarn tension to each yarn simultaneously.
The thread tension applied to each thread by the thread tension mechanism is set to be the reference value for thread tension when the fine adjustment mechanism is located at the center (origin position) of the adjustment range. In order to change the thread tension of each thread to make the reference value, which is the starting point of thread tension adjustment, the thread tension by the fine tension mechanism is changed at the same time as the thread tension is changed by the thread tension mechanism. It is necessary to restore (reset) the value.
Therefore, a mechanism is known that can reset the fine adjustment mechanism in conjunction with a change in the thread tension by the thread tension mechanism (see, for example, Patent Documents 2 and 3).

  Specifically, as shown in FIG. 13, in the thread tension adjusting device 100, when the operator operates the dial 101, the dial shaft gear 103 fixed to the dial shaft 102 rotates, and the cam shaft gear 104 and the cam shaft 105 are rotated. And the cam 106 rotates in conjunction with it. When the cam surface 106a of the cam 106 is in contact with the spring receiving member 107 and the cam 106 rotates and the cam surface 106a changes in the axial direction, the position of the spring receiving member 107 changes in the axial direction accordingly. Since the pair of plates 108 and 108 arranged symmetrically between the spring receiving member 107 and the spring receiving member 109 are pressed against the spring receiving member 107 by the spring 110 and the spring receiving member 109, the position of the spring receiving member 107 is changed. When changed, the pressure applied to the plate 108 by the spring 110 changes. By changing the pressure of the plate 108, the tension of the yarn sandwiched between the plates 108 changes. At this time, a plurality of similar mechanisms that share the cam shaft 105 operate simultaneously to set a plurality of yarn tensions simultaneously.

  Further, when finely adjusting the thread tension of each thread, when the operator rotates the fine adjustment dial 111, the intermediate gear 112 and the fine adjustment gear 113 rotate in conjunction with each other. The inner diameter of the fine adjustment gear 113 is a female screw and is screwed into a male thread portion cut by the thread tension shaft 114. Therefore, when the fine adjustment gear 113 rotates, the fine adjustment gear 113 itself moves in the axial direction. Become. As a result, the amount of compression of the spring 110 pressed against the spring receiver 109 and the plate 108 by the fine adjustment gear 113 changes, so that the pressure applied to the plate 108 changes and the yarn tension is adjusted.

In addition, each time the thread tension setting is switched, the protrusion disposed on the side surface of the cam 106 pushes up the contact portion b of the reset lever (upper) 115 and the reset lever (lower) 116, and the reset lever (upper) 115 · (Bottom) 116 operates in the d direction shown. At this time, if the fine adjustment dial 111 is not at the origin position, the reset lever (upper) 115 / (lower) 116 pushes the projection c of the fine adjustment dial 111 back to the origin position. The mechanism is reset to the home position. When the reset of the fine adjustment mechanism is completed, the reset levers (upper) 115 and (lower) 116 return to the state before the reset operation by the reset spring 117 with the contact portion b disengaged from the protrusion of the cam 106.
Japanese Utility Model Publication No. 4-130769 Japanese Patent Laid-Open No. 11-207071 Japanese Patent No. 2686188

  However, in the mechanism shown in FIG. 13, since the thread tension mechanism and the fine adjustment mechanism are always interlocked, even if it is not desired to reset the fine adjustment mechanism, the interlock between the thread tension mechanism and the fine adjustment mechanism is disconnected. I couldn't.

  The present invention has been made to solve the above-described problem, and an object thereof is to provide a thread tension device for a sewing machine that can arbitrarily select interlocking / non-interlocking between a thread tension mechanism and a fine adjustment mechanism. To do.

  According to the first aspect of the present invention, there is provided a thread tension adjusting mechanism that simultaneously adjusts the thread tension of each thread in a sewing machine that performs sewing using a plurality of threads by driving one drive source or by manual operation, and the tension of each thread. In a thread tension device of a sewing machine comprising: a thread tension fine adjustment mechanism that finely adjusts individually by manual operation; and a reset mechanism that returns a tension applied to each thread to a reference value by the thread tension fine adjustment mechanism. An operation of applying tension to each thread only with the adjustment mechanism, and a reference of the tension of each thread by the thread tension fine adjustment mechanism in conjunction with the operation of the thread tension adjustment mechanism during the operation of the thread tension adjustment mechanism. The operation of returning to the value is alternately performed.

According to the first aspect of the present invention, when the operation of applying tension to each thread is performed only by the thread tension adjusting mechanism, the thread tension adjusting mechanism and the thread tension fine adjusting mechanism are not interlocked, and the thread tension adjustment is performed. When performing the operation of returning the tension of each thread by the thread tension fine adjustment mechanism to the reference value by the reset mechanism in conjunction with the operation of the thread tension adjustment mechanism during the operation of the mechanism, the thread tension adjustment mechanism and the thread tension fine adjustment The mechanism is linked.
By alternately performing these operations, it is possible to arbitrarily select interlocking / non-interlocking between the thread tension adjusting mechanism and the thread tension fine adjusting mechanism.

  According to a second aspect of the present invention, in the thread tension device of the sewing machine according to the first aspect, the fine tension adjustment mechanism includes a fine adjustment dial that adjusts a tension applied to the yarn by a rotation operation, and the reset mechanism. Is a camshaft that is rotated by the operation of the yarn tension adjusting mechanism, a reset cam that is provided on the camshaft and that has a protrusion protruding outward, and an outer edge of the reset cam is sandwiched in two directions, respectively. And a reset lever whose one end is rotatably coupled and the other end is engaged with the adjustment dial. The reset lever is configured so that the protrusion is abutted by rotation of the reset cam. By touching, the fine adjustment dial is moved to return the tension of each thread by the thread tension fine adjustment mechanism to a reference value.

According to the second aspect of the present invention, when the cam shaft is rotated by the operation of the yarn tension adjusting mechanism, the reset cam is also rotated. Here, since the reset lever is provided on the outer edge of the reset cam, when the protrusion of the reset cam touches the reset lever, the reset lever rotates around one end and moves the fine adjustment dial to move the thread tension slightly. The tension of each thread by the adjusting mechanism is returned to the reference value.
Thus, the fine adjustment dial can be moved by moving the reset lever only when the protrusion of the reset cam comes into contact with the reset lever. Therefore, by setting the position of the protrusion, it is possible to arbitrarily select interlocking / non-interlocking between the thread tension adjusting mechanism and the thread tension fine adjusting mechanism.

  According to a third aspect of the present invention, in the thread tension device of the sewing machine according to the second aspect, when the fine adjustment dial is in a reset position, a contact with the reset lever formed on the fine adjustment dial is provided. The contact surface has a shape that is not located within the operating range of the lever.

According to invention of Claim 3,
After the fine adjustment dial is returned to the reset position by the reset lever, even if the reset levers move away from each other, they do not interfere with the contact surface of the fine adjustment dial. The assembly work becomes easy.

  According to a fourth aspect of the present invention, in the thread tension device of the sewing machine according to the second or third aspect, a speed reduction mechanism is provided that decelerates the drive of the thread tension adjusting mechanism and transmits the speed to the camshaft. To do.

  According to the fourth aspect of the present invention, the speed reduction mechanism decelerates the drive of the thread tension adjustment mechanism and transmits the reduced speed drive to the cam shaft, so that the thread tension adjustment mechanism and the cam shaft are driven by the same shaft. This eliminates the need to reduce the operating torque of the yarn tension adjusting mechanism and improve operability.

According to the first aspect of the present invention, when the operation of applying tension to each thread is performed only by the thread tension adjusting mechanism, the thread tension adjusting mechanism and the thread tension fine adjusting mechanism are not interlocked, and the thread tension adjustment is performed. When performing the operation of returning the tension of each thread by the thread tension fine adjustment mechanism to the reference value by the reset mechanism in conjunction with the operation of the thread tension adjustment mechanism during the operation of the mechanism, the thread tension adjustment mechanism and the thread tension fine adjustment The mechanism is linked.
By alternately performing these operations, it is possible to arbitrarily select interlocking / non-interlocking between the thread tension adjusting mechanism and the thread tension fine adjusting mechanism.

According to the second aspect of the present invention, when the cam shaft is rotated by the operation of the yarn tension adjusting mechanism, the reset cam is also rotated. Here, since the reset lever is provided on the outer edge of the reset cam, when the protrusion of the reset cam touches the reset lever, the reset lever rotates around one end and moves the fine adjustment dial to move the thread tension slightly. The tension of each thread by the adjusting mechanism is returned to the reference value.
Thus, the fine adjustment dial can be moved by moving the reset lever only when the protrusion of the reset cam comes into contact with the reset lever. Therefore, by setting the position of the protrusion, it is possible to arbitrarily select interlocking / non-interlocking between the thread tension adjusting mechanism and the thread tension fine adjusting mechanism.

  According to the third aspect of the present invention, after the fine adjustment dial is returned to the reset position by the reset lever, even if the reset levers are moved away from each other, they do not interfere with the contact surface of the fine adjustment dial. The adjustment of the operation range of the reset lever may be coarse, and the assembly work is facilitated.

  According to the fourth aspect of the present invention, the speed reduction mechanism decelerates the drive of the thread tension adjustment mechanism and transmits the reduced speed drive to the cam shaft, so that the thread tension adjustment mechanism and the cam shaft are driven by the same shaft. This eliminates the need to reduce the operating torque of the yarn tension adjusting mechanism and improve operability.

<Configuration of sewing thread tension device>
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiment, an overlock sewing machine that performs sewing using a plurality of threads will be described as an example.
As shown in FIG. 1, the thread tension device 1 of the sewing machine includes a thread tension adjusting mechanism 10 that simultaneously adjusts the thread tension of each thread of the sewing machine by one stepping motor, and individual fine adjustment of the tension of each thread manually. And a reset mechanism 50 for returning the tension applied to each yarn by the yarn tension fine adjustment mechanism 30 to a reference value.

(Thread tension adjusting mechanism)
As shown in FIGS. 1 to 3, the yarn tension adjusting mechanism 10 includes a stepping motor 11 provided on a base F, a motor gear 12 provided on an output shaft of the stepping motor 11 and rotating together with the output shaft, and the motor gear. And a yarn tension adjusting cam gear 14 provided so as to come into contact with a cam portion 13 a formed on the reduction gear 13.
The yarn tension adjusting cam gear 14 is supported by a yarn tension adjusting cam shaft 15 serving as a rotating shaft. The yarn tension adjusting cam shaft 15 is supported by the base F. The yarn tension adjusting cam shaft 15 is provided with a plurality of yarn tension adjusting cams 16 corresponding to each yarn. The yarn tension adjusting cam 16 is formed with a cam surface corresponding to the tension applied to each yarn. That is, the cam surface of the yarn tension adjusting cam 16 is formed such that the height in the axial direction of the yarn tension adjusting cam shaft 15 is different depending on the tension applied to each yarn. Accordingly, the yarn tension adjusting cam 16 functions as a height adjusting member that adjusts the height of the yarn tension adjusting spring 24 (described later). A reset gear 17 described later is provided at one end of the yarn tension adjusting cam shaft 15.

  The base F is provided with a thread tension shaft 21 parallel to the thread tension adjusting cam shaft 15. The thread tension shaft 21 is provided with a spring receiving member 22 in contact with the thread tension adjusting cam 16 corresponding to each thread tension adjusting cam 16. The spring receiving member 22 is formed in a cylindrical shape, and both ends thereof have a shape in which the diameter is increased. The spring receiving member 22 is formed with a contact protrusion 22 a that contacts the thread tension adjusting cam 22. The thread tension shaft 21 is provided with a biasing spring 23 between the base F and one end of the spring receiving member 22. The urging spring 23 is provided with a spring receiving member 22 in a compressed state, and the urging spring 23 presses the spring receiving member 22 with its restoring force. That is, the yarn tension adjusting cam 16 is pressed from the protrusion 22 a by the biasing force of the biasing spring 23.

  At the other end portion of the spring receiving member 22, a plate pressing block 25 is provided with a thread tension adjusting spring 24 interposed therebetween. The dish presser block 25 is provided with a dish 26 for applying tension to the yarn. An adjustment block 27 is provided at a position facing the dish pressing block 25. The adjustment block 27 is provided with a plate 28 at a position facing the plate 26. That is, tension can be applied to the yarn by the dish 26 and the dish 28.

(Thread tension fine adjustment mechanism)
As shown in FIGS. 1 to 3, the thread tension fine adjustment mechanism 30 includes a fine adjustment gear 31 that is provided on the thread tension shaft 21 and is movable with respect to the base F in the axial direction of the thread tension shaft 21. I have. The fine adjustment gear 31 is formed with a screw groove 31a that is screwed into a screw groove formed in the base F, and the axis of the thread tension shaft 21 is rotated by rotating the fine adjustment gear 31 around the thread tension shaft 21. Move in the direction. The fine adjustment gear 31 is rotatable with respect to the adjustment block 27, but is attached to the adjustment block 27 so that movement of the thread tension shaft 21 in the axial direction relative to the adjustment block 27 is restricted. Accordingly, the adjustment block 27 can move along the axial direction of the thread tension shaft 21 together with the fine adjustment gear 31 by the rotation of the fine adjustment gear 31, but the fine adjustment gear 31 is prevented from being detached from the adjustment block 27. ing. A fine adjustment dial 32 is connected to the fine adjustment gear 31 via a reduction gear (not shown). That is, the fine adjustment gear 31 can be rotated by rotating the fine adjustment dial 32 by manual operation.
The fine adjustment dial 32 is rotatably provided on the base F. The fine adjustment dial 32 is formed in a sectional view arc shape in which a part of a cylinder is cut out. When the fine adjustment dial 32 is at the position where the fine adjustment dial 32 is reset by the reset mechanism 50, the contact surface with the reset levers 53 and 54 formed on the fine adjustment dial 32 has the reset levers 53 and 54. It is formed in a shape not located within the operating range.

(Reset mechanism)
As shown in FIGS. 1 to 3, the reset mechanism 50 includes a reset cam shaft 51 provided on the base F, a reset cam 52 pivotally supported on the reset cam shaft 51, and an outer edge of the reset cam 52 from two directions. Reset levers 53 and 54, which are provided so as to be sandwiched, and whose one end portions are rotatably connected to each other and whose other end portions are engaged with the fine adjustment dial 32, are provided.
The reset cam shaft 51 is provided in parallel to the thread tension adjusting cam shaft 15 and the thread tension shaft 21. A reset gear 55 that meshes with the reset gear 17 is provided at one end of the reset cam shaft 51. The reset gear 55 has, for example, four times the number of teeth with respect to the reset gear 17 and is configured to have a gear ratio of 4. Since the reset cam shaft 51 is connected to the yarn tension adjusting cam shaft 15 of the yarn tension adjusting mechanism 10 via the reset gears 17 and 55, the reset cam shaft 51 is also decelerated by the rotation of the yarn tension adjusting cam shaft 15. Rotate in the state. That is, the speed reduction mechanism 40 is configured by including the reset gear 17 and the reset gear 55.

As shown in FIGS. 4 to 6, the reset cam shaft 51 is provided with a reset cam 52 having a protrusion 52 a that protrudes outward. The reset cam 52 is formed in a substantially disk shape when viewed from the front, and a protrusion 52 a is formed at a position facing the reset cam shaft 51.
The reset lever 53 is formed to cover the reset cam 52 from above and to extend toward the fine adjustment dial 32. A protrusion 53 a that contacts the outer edge of the reset cam 52 is formed on the outer edge of the reset lever 53 that faces the reset cam 52. The reset lever 54 is formed so as to cover the reset cam 52 from below and to extend toward the fine adjustment dial 32. A protrusion 54 a that contacts the outer edge of the reset cam 52 is formed on the outer edge of the reset lever 54 that faces the reset cam 52.
The protrusions 53 a and 54 a are always in contact with the outer edge of the reset cam 52, and move following the unevenness of the outer edge of the reset cam 52 as the reset cam 52 rotates. Thereby, the reset levers 53 and 54 come in contact with each other.
One end portions of the reset levers 53 and 54 are rotatably connected by a shaft member 56 and an E ring 57. The other ends of the reset levers 53 and 54 are formed so as to come into contact with the contact surface 32 a formed on the cut-out surface of the fine adjustment dial 32. The reset lever 53 and the reset lever 54 are connected by a spring 58 between one end and the other end, and are biased in a direction in which the other ends approach each other.

As shown in FIG. 4, since the protrusions 53a and 54a of the reset levers 53 and 54 are provided so as to contact the outer edge of the reset cam 52, the reset cam 52 rotates and resets as shown in FIG. When the projection 52a of the cam 52 and the projections 53a, 54a of the reset levers 53, 54 are in contact with each other, the reset levers 53, 54 have one end corresponding to the height of the projections 52a, 53a, 54a. Rotate to center.
Further, since the gear ratio between the reset gear 17 and the reset gear 55 is 4, the reset gear 55 rotates 1/4 while the reset gear 17 rotates once. By utilizing this, the yarn tension adjusting mechanism 10 and the yarn tension fine adjusting mechanism 30 are not always interlocked simultaneously.

  Referring to FIG. 6, before the operation of the thread tension device 1, the protrusions 52a of the reset cam 52 are arranged to face P1 and P3, respectively, and when the thread tension device 1 is operated from this state, When the thread tension adjusting cam shaft 15 enters the second rotation (when it starts to rotate from P2) and the fourth rotation (when it starts to rotate from P4), the protrusion 52a of the reset cam 52 and the protrusions of the reset levers 53 and 54 53a and 54a come into contact with each other, so that the reset levers 53 and 54 rotate against the urging force of the spring 58. The fine adjustment dial 32 is rotated by rotating the reset levers 53 and 54 so that the other ends of the reset levers 53 and 54 are separated from each other and come into contact with the contact portion 32a of the fine adjustment dial 32. With this series of operations, the tension applied to the yarn by the fine adjustment dial 32 can be returned to the reference value.

  Accordingly, when the yarn tension adjusting cam shaft 15 of the yarn tension adjusting mechanism 10 is rotated an odd number of times, the target tension can be applied to the yarn and the tension applied by the fine adjustment dial 32 can be returned to the reference value. First, when the thread tension adjusting cam shaft 15 is rotated an even number of times, the tension applied by the thread tension adjusting mechanism 10 is interrupted and the tension applied by the fine adjustment dial 32 is returned to the reference value (reset). it can. In other words, the operation of applying tension to each yarn only by the yarn tension adjusting mechanism 10 and the operation of the yarn tension adjusting mechanism 10 during the operation of the yarn tension adjusting mechanism 10 cause each yarn to be adjusted by the yarn tension fine adjusting mechanism 30. The operation of returning the tension to the reference value by the reset mechanism 50 is alternately performed.

<Description of Operation of Embodiment>
Next, the operation of the thread tension device 1 will be described.
When the stepping motor 11 is driven, the driving rotates the thread tension adjusting cam shaft 15 via the motor gear 12, the reduction gear 13, and the thread tension adjusting cam gear 14. The thread tension adjusting cam 16 is rotated by the rotation of the thread tension adjusting cam shaft 15, and the spring receiving member 22 extends along the axial direction of the thread tension shaft 21 due to the cam shape of the thread tension adjusting cam 16 that contacts the contact protrusion 22 a. Move. Due to the movement of the spring receiving member 22, the urging force applied from the thread tension adjusting spring 24 of the counter presser block 25 changes, so that the urging force between the tray 26 and the tray 28 also changes, changing the tension applied to the yarn. be able to. Further, by rotating the fine adjustment dial 32, the adjustment block 27 can be moved along the thread tension shaft 21, so that the height of the thread tension adjustment spring 24 is changed, and the tray 26, the tray 28, The urging force between the two can also be changed to finely adjust the tension applied to the yarn.
In the first rotation, the rotation of the yarn tension adjusting cam shaft 15 is transmitted to the reset cam shaft 51 via the reset gears 17 and 55. Therefore, the reset cam shaft 51 also rotates, and the reset cam 52 provided on the reset cam shaft 51 also rotates.
In the first rotation of the thread tension adjusting cam shaft 15, the protrusion 52a of the reset cam 52 and the protrusions 53a and 54a of the reset levers 53 and 54 do not come into contact with each other. The dial 32 does not move either. Therefore, the tension applied to the yarn by the fine adjustment dial 32 does not return to the reference value.

However, when the stepping motor 11 is further driven and the yarn tension adjusting cam shaft 15 tries to enter the second rotation, the protrusion 52a of the reset cam 52 and the protrusions 53a and 54a of the reset levers 53 and 54 come into contact with each other, and the reset lever 53 and 54 rotate so as to be separated from each other around the shaft member 56 at one end. As a result, the other end portions 53b and 54b of the reset levers 53 and 54 press the fine adjustment dial 32, and the fine adjustment dial 32 rotates in a direction to return to the origin position and is applied to the yarn by the fine adjustment dial 32. The tension returns to the reference value.
When the stepping motor 11 is further driven and the thread tension adjusting cam shaft 15 enters the third rotation, the protrusion 52a of the reset cam 52 and the protrusions 53a and 54a of the reset levers 53 and 54 do not come into contact with each other. 53 and 54 do not rotate, and the fine adjustment dial 32 does not move. Therefore, the tension applied to the yarn by the fine adjustment dial 32 does not return to the reference value.
When the stepping motor 11 is further driven and the yarn tension adjusting cam shaft 15 enters the fourth rotation, the protrusion 52a of the reset cam 52 and the protrusions 53a and 54a of the reset levers 53 and 54 come into contact with each other. 53 and 54 rotate so as to be separated from each other around the shaft member 56 at one end. As a result, the other end portions 53 b and 54 b of the reset levers 53 and 54 press the fine adjustment dial 32, and the fine adjustment dial 32 rotates in a direction to return to the origin position and is applied to the yarn by the fine adjustment dial 32. The tension returns to the reference value.
Thereafter, the above operation is repeated until the sewing is completed.

<Effects of Embodiment>
As described above, according to the thread tension device 1 of the sewing machine, when performing an operation of applying tension to each thread using only the thread tension adjusting mechanism 10, the thread tension adjusting mechanism 10 and the thread tension fine adjusting mechanism 30 are not connected. When the operation of the yarn tension adjusting mechanism 10 is performed in conjunction with the operation of the yarn tension adjusting mechanism 10, the operation of returning the tension of each yarn by the yarn tension fine adjusting mechanism 30 to the reference value by the reset mechanism 50 is performed. The yarn tension adjusting mechanism 10 and the yarn tension fine adjusting mechanism 30 are interlocked.
By alternately performing these operations, it is possible to arbitrarily select interlocking / non-interlocking between the thread tension adjusting mechanism 10 and the thread tension fine adjusting mechanism 30.

When the reset cam shaft 51 is rotated by the operation of the yarn tension adjusting mechanism 10, the reset cam 52 is also rotated. Here, since reset levers 53 and 54 are provided on the outer edge of the reset cam 52, when the protrusion 52a of the reset cam 52 touches the reset levers 53 and 54, the reset levers 53 and 54 are shaft members at one end. 56, the fine adjustment dial 32 is moved, and the tension of each thread by the thread tension fine adjustment mechanism 30 is returned to the reference value.
Thus, the fine adjustment dial 32 can be moved by moving the reset levers 53 and 54 only when the protrusion 52a of the reset cam 52 comes into contact with the reset levers 53 and 54. Therefore, by setting the position of the protrusion 52a, it is possible to arbitrarily select whether the yarn tension adjusting mechanism 10 and the yarn tension fine adjusting mechanism 30 are linked or not.

  Further, the speed reduction mechanism 40 decelerates the driving of the thread tension adjusting mechanism 10 and transmits the reduced speed driving to the reset cam shaft 51. Therefore, it is necessary to drive the thread tension adjusting mechanism 10 and the reset cam shaft 51 on the same axis. Thus, the operating torque of the yarn tension adjusting mechanism 10 can be reduced, and the operability can be improved.

<Others>
The present invention is not limited to the above embodiment. For example, the speed reduction mechanism is not limited to that shown in FIGS. 1 to 3, and as shown in FIG. 7, a small pulley 41 is provided on the thread tension adjusting cam shaft 15, and a large pulley 42 is provided on the reset cam shaft 51. You may comprise so that these pulleys 41 and 42 may be connected with the belt 43. FIG. Even in such a configuration, it is a matter of course that the pulleys 41 and 42 are designed so that the rotational speed of the yarn tension adjusting cam shaft 15 becomes 1/4 of the rotational speed of the reset cam shaft 51.

  Further, as shown in FIG. 8 (a), the reset levers 61 and 62 are rotatably connected at substantially the center thereof, and claw-like protrusions 61a and 62a are formed at one end portions of the reset levers 61 and 62, respectively. The protrusions 61 a and 62 a may be configured to contact the outer edge of the reset cam 52. Also in this case, as shown in FIG. 8B, when the protrusions 52a of the reset cam 52 and the protrusions 61a and 62a of the reset levers 61 and 62 are in contact with each other, the reset levers 61 and 62 are The fine adjustment dial 32 can be moved to contact the fine adjustment dial 32 and returned to the home position. The contact surface 32a with the reset lever formed on the fine adjustment dial 32 has a shape that does not fall within the lever operating range when the fine adjustment dial 32 is in the reset position.

  Further, as shown in FIG. 9A, the reset levers 63 and 64 are rotatably connected at one end thereof, and claw-like projections 63a and 64a are formed near the center in the longitudinal direction of the reset levers 63 and 64. However, the protrusions 63a and 64a may be configured to contact the outer edge of the reset cam 71. Even in this case, as shown in FIG. 9B, when the recess 71a formed in the reset cam 71 and the projections 63a and 64a of the reset levers 63 and 64 are in contact with each other, 64 moves and comes into contact with the fine adjustment dial 32 so that the fine adjustment dial 32 can be returned to the original position. The contact surface 32a with the reset lever formed on the fine adjustment dial 32 has a shape that does not fall within the lever operating range when the fine adjustment dial 32 is in the reset position. Further, since the reset cam 71 is formed with a recess 71a instead of the protrusion, the other ends of the reset levers 63 and 64 need to cross each other.

  Also, as shown in FIG. 10A, the reset levers 65 and 66 are rotatably connected at one end thereof, and claw-like projections 65a and 66a are formed near the center in the longitudinal direction of the reset levers 65 and 66. However, the protrusions 65 a and 66 a may be configured to contact the outer edge of the reset cam 72. The reset cam 72 has two convex portions on the outer edge. Also in this case, as shown in FIG. 10B, when the projection 72a formed on the reset cam 72 and the projections 65a and 66a of the reset levers 65 and 66 are in contact with each other, the reset lever 65 , 66 move to contact the fine adjustment dial 32, and the fine adjustment dial 32 can be returned to the origin position. Conversely, when the recess 72b formed in the reset cam 72 and the projections 65a and 66a of the reset levers 65 and 66 are in contact with each other, the reset levers 65 and 66 do not move and the fine adjustment dial 32 moves. I will not let you. The contact surface 32a with the reset lever formed on the fine adjustment dial 32 has a shape that does not fall within the lever operating range when the fine adjustment dial 32 is in the reset position.

  Further, as shown in FIG. 11 (a), reset levers 61 and 62 having the same shape as the example shown in FIG. The portions 61a and 62a may be formed, and the protrusions 61a and 62a may be configured to contact the outer edge of the reset cam 72 having the same shape as the example shown in FIG. The reset cam 72 has two convex portions on the outer edge. Also in this case, as shown in FIG. 11B, when the projection 72a formed on the reset cam 72 and the projections 61a and 62a of the reset levers 61 and 62 are in contact with each other, the reset lever 61 , 62 move to contact the fine adjustment dial 32, and the fine adjustment dial 32 can be returned to the original position. Conversely, when the recess 72b formed in the reset cam 72 and the protrusions 61a and 62a of the reset levers 61 and 62 are in contact with each other, the reset levers 61 and 62 do not move and the fine adjustment dial 32 moves. I will not let you. The contact surface 32a with the reset lever formed on the fine adjustment dial 32 has a shape that does not fall within the lever operating range when the fine adjustment dial 32 is in the reset position.

  12A, reset levers 63 and 64 having the same shape as the example shown in FIG. 9 are rotatably connected at one end thereof, and claw-like protrusions are located near the centers of the reset levers 63 and 64. The parts 63a and 64a may be formed, and the protrusions 63a and 64a may be configured to contact the outer edge of the reset cam 72 having the same shape as that shown in FIG. The reset cam 72 has two convex portions on the outer edge. Also in this case, as shown in FIG. 12B, when the recess 72b formed in the reset cam 72 and the projections 63a, 64a of the reset levers 63, 64 are in contact with each other, the reset lever 63, 64 moves and comes into contact with the fine adjustment dial 32 so that the fine adjustment dial 32 can be returned to the original position. Conversely, when the convex portion 72a formed on the reset cam 72 and the projections 63a and 64a of the reset levers 63 and 64 are in contact with each other, the reset levers 63 and 64 do not move and the fine adjustment dial 32 is turned on. There is no movement. The contact surface 32a with the reset lever formed on the fine adjustment dial 32 has a shape that does not fall within the lever operating range when the fine adjustment dial 32 is in the reset position.

The perspective view of the thread tension device of a sewing machine. The side view of the thread tension device of a sewing machine. AA sectional drawing in FIG. FIG. 4 is a cross-sectional view taken along line BB in FIG. 3 and shows a state before the fine adjustment dial is operated. FIG. 4 is a cross-sectional view taken along line BB in FIG. 3 and shows a state after the fine adjustment dial is operated. It is BB sectional drawing in FIG. 3, and is a figure explaining operation | movement of a reset mechanism. The front view which shows the other example of the deceleration mechanism. (A) is a schematic diagram which shows the state before restoring the tension | tensile_strength in the other example of a reset mechanism, (b) is a schematic diagram which shows the state after tension release. (A) is a schematic diagram which shows the state before restoring the tension | tensile_strength in the other example of a reset mechanism, (b) is a schematic diagram which shows the state after tension release. (A) is a schematic diagram which shows the state before restoring the tension | tensile_strength in the other example of a reset mechanism, (b) is a schematic diagram which shows the state after tension release. (A) is a schematic diagram which shows the state before restoring the tension | tensile_strength in the other example of a reset mechanism, (b) is a schematic diagram which shows the state after tension release. (A) is a schematic diagram which shows the state before restoring the tension | tensile_strength in the other example of a reset mechanism, (b) is a schematic diagram which shows the state after tension release. (A) is a top view which shows the structure of the conventional thread tension apparatus, (b) is XX sectional drawing in (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thread tension device of sewing machine 10 Thread tension adjusting mechanism 11 Stepping motor (drive source)
30 Thread tension fine adjustment mechanism 32 Fine adjustment dial 40 Reduction mechanism 50 Reset mechanism 51 Reset cam shaft (cam shaft)
52 Reset Cam 52a Projection 53 Reset Lever 53a Projection 54 Reset Lever 54a Projection

Claims (4)

A thread tension adjusting mechanism that simultaneously adjusts the thread tension of each thread in a sewing machine that performs sewing using a plurality of threads by driving one drive source or by manual operation;
A thread tension fine adjustment mechanism that finely adjusts the tension of each thread individually by manual operation;
In a thread tension device of a sewing machine comprising: a reset mechanism that returns the tension applied to each thread by the thread tension fine adjustment mechanism to a reference value;
The operation of applying tension to each thread only by the thread tension adjusting mechanism, and the tension of each thread by the thread tension adjusting mechanism interlocking with the operation of the thread tension adjusting mechanism during the operation of the thread tension adjusting mechanism is reset. A thread tension device for a sewing machine that alternately performs an operation of returning to a reference value by a mechanism. The thread tension fine adjustment mechanism includes a fine adjustment dial for adjusting a tension applied to the thread by a rotation operation,
The reset mechanism is
A camshaft rotating by the operation of the yarn tension adjusting mechanism;
A reset cam provided on the camshaft and having a protrusion protruding outward;
A reset lever that is provided so as to sandwich the outer edge of the reset cam from two directions, one end of which is rotatably connected and the other end is engaged with the adjustment dial,
The reset lever is configured to return the tension of each thread by the thread tension fine adjustment mechanism to a reference value by moving the fine adjustment dial when the protrusion comes into contact with rotation of the reset cam. The thread tension device of the sewing machine according to 1.   The contact surface with the reset lever formed on the fine adjustment dial, when the fine adjustment dial is in a reset position, has a shape that is not located within the operating range of the lever. The thread tension device of the sewing machine according to 2.   4. The thread tension device for a sewing machine according to claim 2, further comprising a speed reducing mechanism that decelerates the driving of the thread tension adjusting mechanism and transmits the speed to the camshaft.

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