JPH0418552Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thread tension display device for a sewing machine, and particularly relates to an improvement in a drive mechanism that transmits rotational force of a thread tension knob to a display means to operate the display means. .

[Conventional technology]

Conventionally, as shown in, for example, Japanese Utility Model Publication No. 57-10300 or Japanese Utility Model Publication No. 60-8858, thread tension can be adjusted by changing a pair of thread tension discs and the thread clamping pressure by rotating a thread tension knob. A thread tension display device for a sewing machine is generally known, which adjusts the thread tension and displays the adjusted state of the thread tension using a display means operated by rotating a thread tension knob.

[Problem that the invention attempts to solve]

By the way, in an overlock sewing machine or the like in which stitches are formed by delicate intertwining of needle thread and looper thread, delicate adjustment of thread tension is required. For this reason, the conventional structure has been such that the thread tension can be adjusted by rotating the thread tension knob multiple times. On the other hand, it is more convenient for the user if the display means for displaying the adjustment state of the thread tension displays all adjustment states within the range of one rotation. Therefore, conventionally, a deceleration mechanism is provided between the thread tension knob and the display means to drive the display means at a reduced speed.

However, since the conventional speed reduction mechanism is composed of a gear mechanism including an internal gear and gears that mesh with the internal gear, there is a problem that the structure is complicated and the cost is high.

In addition, the gear mechanism cannot greatly change the reduction ratio without moving the center position of each gear, so when changing the reduction ratio and applying it to various sewing machines, you must not only replace the gears but also change the thread tension knob. It is also necessary to change the design of other parts such as the installation position of the machine, and there is also the problem that it is virtually impossible to change a part of a single device and apply it to various sewing machines.

The present invention was developed in view of the current situation, and has a simple structure, small size, and low cost, and can be used as a lockstitch sewing machine for home use that can adjust the thread tension within one rotation of the thread tension knob with the minimum necessary changes. Another object of the present invention is to provide a thread tension display device for a sewing machine which can also be applied to an overlock sewing machine in which thread tension is adjusted by rotating a thread tension knob multiple times.

[Means for solving problems]

The present invention includes a pair of thread tension discs that sandwich the thread, and a
A thread tension knob that adjusts the thread clamping pressure of both thread tension discs by a rotation operation exceeding one rotation; a driving member having a guide; an actuating member that engages with the guide and moves relative to the guide as the driving member rotates; The present invention is characterized by comprising a display means for displaying the adjustment state of the thread tension by relative movement of the members.

[Effect]

The thread tension display device for a sewing machine according to the present invention includes a drive member that rotates more than one rotation in conjunction with a thread tension knob, and a spiral guide provided on the drive member that engages with the drive member to rotate the drive member. The movement of the thread tension knob is transmitted to the display means via the actuating member which moves relatively along the guide as the thread tension knob moves. Therefore, it is possible to simplify the structure and reduce costs compared to conventional gear mechanisms that use gear mechanisms. In addition, by simply using drive members having spiral guides with different numbers of turns, the reduction ratio can be greatly changed without changing the positional relationships of other members, making it possible to apply the invention to various sewing machines.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 9.

FIG. 1 shows an example of a thread tension display device for a sewing machine according to the present invention.
A pair of thread tension discs 2a, 2 that sandwich a thread (not shown)
b, and the thread clamping pressure by these thread tension discs 2a, 2b is applied to the drive shaft 3 as shown in FIG.
Adjustment is made by rotating a thread tension knob 4 fixed to the outer end of the thread tension knob 4.

As shown in FIG. 1, the drive shaft 3 is rotatably inserted into a cylindrical fixed shaft 6 which is fixed through the face plate 5 of the sewing machine. That is, the fixed shaft 6 is inserted from the outside into the center hole 5a of the face plate 5 with the E ring 7 and the washer 8 attached as shown in FIG. It is fixed to the face plate 5 by screwing a nut 10 through it. and drive shaft 3
is inserted into this fixed shaft 6, and the nut 10
A retaining nut 11 attached to a portion protruding from the thread tension knob 4 prevents the needle from coming off the fixed shaft 6, and an elastic washer 12 interposed between the outer end surface of the fixed shaft 6 and the inner surface of the thread tension knob 4, The play in the axial direction of the drive shaft 3 is absorbed. Further, a drive member 13, which will be described in detail later, is fixed to the inner end of the drive shaft 3 so as to rotate together with the drive shaft 3.

On the other hand, on the outer periphery of the portion of the fixed shaft 6 that protrudes outward from the face plate 5, as shown in FIG.
4 and a spring receiving member 15 are each mounted so as to be slidable in the axial direction, and the thread tension plate 2
a, 2b and the thread pinching pressure release member 14 are
As shown in the figure, a rotation prevention piece 1 protrudes from the face plate 5.
6 prevents rotation. Further, as shown in FIG. 1, a thread tension nut 18 is screwed onto a male threaded portion 17 formed on the outer peripheral portion of the outer end side of the fixed shaft 6. A pair of thread tension discs 2a, 2
A coil spring 19 is interposed to apply a predetermined thread clamping pressure to b.

The spring receiving member 15 and the thread tension nut 18
For example, 15 or 12 grooves 15 are formed at equal intervals in the circumferential direction as shown in FIGS.
Predetermined grooves 15a and 18a of these grooves engage with ribs 4a provided, for example, three at equal intervals in the circumferential direction on the inner surface of the cap-shaped thread tension knob 4. As a result, the spring receiving member 15 and the thread tension nut 18 rotate together with the thread tension knob 4. Due to this rotation, the thread tension nut 18 is threaded along the male threaded portion 17 from the position of the E ring 20 attached to one end of the male threaded portion 17 to the position of the ring groove 21 provided at the other end. By changing the distance between the receiving member 15 and the thread tension discs 2a and 2b, the thread clamping pressure applied to the pair of thread tension discs 2a and 2b is adjusted. Note that this thread clamping pressure is released by sliding the thread clamping pressure release member 14 to the right in FIG. The thread tension discs 2a and 2b are designed to prevent the thread from getting caught between the thread tension plates 2a and 2b. This will be explained in detail later.

On the other hand, the drive member 13 fixed to the inner end of the drive shaft 3, which rotates together with the thread tension knob 4, has a disk portion 13a and one side of the disk portion 13a, as shown in FIGS. 3 and 4. A cylindrical portion 13 protruding from the plate surface of
A spiral groove-shaped guide 22 centered on the rotation center of the drive member 13 is provided on the other plate surface of the disc portion 13a. The drive member 13 is fixed to the drive shaft 3 with the cylindrical portion 13b facing the face plate 5, as shown in FIG. In addition, the cylindrical portion 13 on the inner surface of the face plate 5
As shown in FIGS. 1 and 5, two arcuate guide pieces 23 are provided at the portion corresponding to b to make sliding contact with the inner surface of the cylindrical portion 13b, thereby stabilizing the rotation of the drive member 13. ing.

As shown in FIGS. 1 and 6, an actuating member 24 is disposed at an inner position of the drive member 13 configured in this manner so as to be able to swing around its lower end as a fulcrum. , is engaged with the guide 22 of the drive member 13 via an engagement pin 25. The engagement pin 25 moves relatively along the guide 22 as the drive member 13 rotates, thereby swinging the operating member 24 left and right.

That is, the actuating member 24 is shown in FIG. 1, FIG.
As shown in FIGS. 7 and 8, a swing arm 24a whose lower end is swingably attached to a support shaft 26 provided on the inner surface of the face plate 5 via a locking nut 27.
and a scale plate support piece 24b integrally provided at the upper end portion of the swing arm 24a, and a sixth
As shown in FIG. 7 and FIG. 7, a support arm 28 that supports the engagement pin 25 is provided to protrude in the lateral direction, and the scale plate support piece 24b has, for example, 1 to 1 on the outer surface as shown in FIG. A scale plate 29 having a numeric scale 29a of 9 is provided. The lower end of this scale plate 29 is engaged with a swing guide piece 30 projecting in an L shape from the inner surface of the face plate 5, as shown in FIGS. 1 and 6, and guides the swing of the actuating member 24. It's becoming like that.

Further, on the portion of the face plate 5 corresponding to the scale plate 29, there is a numerical scale 2 as shown in FIGS. 1 and 9.
A display window 31 at 9a is opened so that the numerical scale 29a can be viewed from the outside of the face plate 5, and a pointer 32 in the shape of, for example, an inverted triangle is provided directly above the display window 31. . Then, this pointer 32 and the numerical scale 29 of the scale plate 29
a constitutes a display means 33 that displays the adjustment state of the thread tension.

Next, the operation of this embodiment will be explained.

As shown in FIG. 1, when the thread tension nut 18 is located at the right end in the figure of the male threaded portion 17 provided on the fixed shaft 6, the distance between the thread tension nut 18 and the spring receiving member 15 is at its maximum. Large, with a pair of thread tension discs 2
The yarn clamping pressure by a and 2b is at its weakest state.

In this state, the engagement pin 25 provided on the actuating member 24 is located at the outer end of the spiral groove-shaped guide 22, and the numerical scale 29a of the scale plate 29 indicates that the smallest scale number "1" is the pointer. It corresponds to 32.

In this state, when the thread tension knob 4 shown in FIG. Because
The spring receiving member 1 is rotated in accordance with the rotation of the thread tension knob 4.
5 and thread tension nut 18 will also rotate. Then, the thread tension nut 18 screws along the male threaded portion 17 to the left in FIG. .

When the thread tension nut 18 is screwed to the left in FIG. 1, the distance between it and the spring receiving member 15 becomes gradually narrower, and the pressing force exerted by the coil spring 19 gradually increases. Since the spring receiving member 15 and the thread clamping pressure release member 14 are slidable in the axial direction of the fixed shaft 6, the pressing force of the coil spring 19 is applied to the pair of thread tension discs 2a and 2b, and the force is increased. A pair of thread tension discs 2a,
The yarn clamping pressure by 2b will gradually increase. At this time, as the thread tension knob 4 rotates, not only the thread tension nut 18 but also the spring receiver member 15 rotates at the same time, so that the coil spring 19 does not twist and can perform stable expansion and contraction operations, and the rotating spring receiver The thread tension discs 2a, 2 are directly connected to the member 15.
Rather than pressing b, the structure is such that the pressure is indirectly applied via the thread clamping pressure release member 14 which is prevented from rotating, so that a stable pressing force is applied to the thread tension disc 2.
a, 2b. Therefore, the thread clamping pressure that corresponds to the amount of rotation of the thread tension knob 4 can always be obtained.

On the other hand, from the state shown in FIG.
When the drive shaft 3 is rotated clockwise in FIG. 9, the drive shaft 3 integrated therewith also rotates in the same direction, and the drive member 13 attached to its inner end also rotates counterclockwise in FIG.

When the driving member 13 rotates counterclockwise in FIG. Move to part. As a result, the actuating member 24 swings counterclockwise in FIG. 6, and the scale plate 29 integrated therewith also swings in the same direction.

When the scale plate 29 swings counterclockwise in FIG. 6, the scale number "1" initially corresponds to the pointer 32, but eventually the scale number "5" corresponds to the pointer 32, as shown in FIG. When the thread tension knob 4 is further rotated to move the engagement pin 25 to the inner end of the guide 22, the scale number "9" corresponds to the pointer 32.

Note that if the thread tension knob 4 is rotated counterclockwise in FIG. 9, the drive member 13 will be rotated clockwise in FIG.
The inner winding part of 2 gradually transitions to the outer winding part. As a result, the scale plate 29 moves to the ninth position.
Moving to the left in the figure, the smaller scale numbers on the numerical scale 29a will correspond to the pointer 32 one after another.

On the other hand, due to the counterclockwise rotation of the thread tension knob 4 in FIG. 9, the thread tension nut 18 is screwed to the left in FIG. expands, and the thread clamping pressure by the pair of thread tension discs 2a, 2b gradually decreases.

By the way, when changing the thread with the thread tension adjusted using the thread tension knob 4, it is also possible to completely remove the previous thread and attach the new thread to the sewing machine, but this method is cumbersome to operate. Therefore, normally, the previous thread is cut near the spool, a new thread is tied to this, the previous thread is pulled on the needle side, the knot with the new thread is guided to the position just before the needle, and then the previous thread is tied. The method used is to cut the thread and thread a new thread through the needle hole.

However, when changing the thread using this method, if strong thread clamping pressure is applied to the pair of thread tension discs 2a and 2b, the thread knot may
When passing between a and 2b, there is a risk that the thread may get caught in this part and break.

Therefore, in this embodiment, in such a case, the thread tension disc 2 is forcibly removed using the thread clamping pressure release member 14.
The yarn clamping pressure of a and 2b is released.

That is, once the thread knot has been guided to just before the thread tension discs 2a, 2b, the thread clamping pressure release member 14 is slid to the right in FIG. Then, the biasing force of the coil spring 19 is
Spring receiving member 15 and thread clamping pressure release member 14
Since the tension is applied to the thread tension discs 2a and 2b via the
The thread clamping pressure of the thread tension discs 2a, 2b is forcibly released, allowing the thread to pass through the knot without any hindrance.

Once the thread knot has passed, let go of the thread clamping pressure release member 14. Then, the thread clamping pressure releasing member 14 and the spring receiving member 15 slide back to their original positions due to the biasing force of the coil spring 19, and the same thread clamping pressure as before is applied to the thread tension discs 2a, 2b.

Therefore, by visually checking through the display window 31 which scale number on the numerical scale 29a corresponds to the pointer 32, the thread tension state can be easily grasped.

Further, the thread tension caused by multiple rotations of the thread tension knob 4 is displayed within a predetermined angular swing range of the scale plate 29 by a deceleration mechanism composed of the guide 22 and the operating member 24. , it is easy to check the adjustment status of the thread tension. Moreover, since the structure of the speed reduction mechanism is simple, it can be constructed inexpensively and compactly.

FIGS. 10 and 11 show another embodiment of the present invention, in which the actuating member 24 in the embodiment is shown in FIG.
Instead, an actuating member 34 that reciprocates by the forward and reverse rotation of the driving member 13 is used.

That is, as shown in FIGS. 10 and 11, the actuating member 34 has a structure in which a portion of a strip material corresponding to the driving member 13 is bent to form a bent portion 34a, and both ends thereof are connected to the face plate 5. It is supported in a reciprocating manner by a locking piece 35 provided on the inner surface.

Further, the bending portion 34a of the actuating member 34 is provided with an engaging pin 25 that engages with the guide 22, as shown in FIGS. 10 and 11.
The operating member 34 reciprocates in conjunction with the rotation of the operating member 34, and the right end portion of the operating member 34 in the figure is configured as a scale plate 29, and a portion of the face plate 5 corresponding to the scale plate 29 is provided with a display. A window 31 and a pointer 32 are provided to constitute a display means 33.

Note that, in other respects, the configuration is exactly the same as that of the previous embodiment.

Therefore, even if the reciprocating actuating member 34 is used, the same effects as in the embodiment described above can be obtained.

In both of the above embodiments, the pointer 32 is fixed and the scale plate 29 is movable. Good too. In addition, the scale of the scale plate 29 is the numerical scale 29
The scale is not limited to a, and may be a scale that displays the thickness of the cloth and the type of thread used in relation to each other, for example.

Furthermore, in both of the above embodiments, the driving member 13 having a four-turn spiral groove-shaped guide 22 is used, and the thread tension is adjusted by rotating the thread tension knob 4 four times. There are also sewing machines that adjust the thread tension at a rotation speed of less than 4 rotations. In this case, the driving member 13 in each of the embodiments described above may be used as is, but in this case the amount of movement of the actuating members 24, 34 will be reduced, and the display on the scale plate 29 will have to be changed. Therefore, in this case, for example, a driving member 13 having a guide that connects the inner end and outer end of the guide 22 in each of the above embodiments with the same number of turns as the number of rotations of the thread tension knob 4 may be used. Bye. As a result, not only the display on the scale plate 29 but also the operation member 2
The reduction ratio can be adjusted to the amount of rotation of the thread tension knob 4 without changing the positional relationship of other members such as 4, 34, etc. For this reason. By preparing a plurality of types of drive members 13, the other members can be used as common parts and can be applied to all types of sewing machines, making it possible to significantly reduce costs.

Further, in both of the embodiments described above, the case where the thread tension display device 1 is directly assembled to the face plate 5 has been shown, but the thread tension display device 1 may be made into a unit and then attached to the face plate 5. Further, the guide 22 is not limited to a spiral groove, but may also be a spiral protrusion.
The drive member 13 having the thread tension knob 2 does not need to be directly connected to the drive shaft 3, and may be installed at a remote location as long as it rotates in conjunction with the thread tension knob 4.

[Effect of idea]

As explained above, the present invention involves a thread tension knob that is rotated over one rotation, and a drive member that rotates over one rotation, and a spiral guide provided on this drive member. The movement of the thread tension knob is transmitted to the display means via the operating member that moves relative to the guide as the drive member rotates, so this is compared to the conventional system using a gear mechanism. As a result, the structure can be simplified and downsized, and costs can be reduced.

In addition, by simply changing the winding state of the spiral guide, the reduction ratio can be changed significantly without changing the shape, dimensions, or positional relationships of other parts. It can be applied to

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a thread tension display device showing an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along the - line of the first car,
Fig. 3 is a block diagram of the drive member seen from the guide side, Fig. 4 is a sectional view taken along the - line in Fig. 3, Fig. 5 is a block diagram of the face plate seen from the left side of Fig. 1, and Fig. 6 is a block diagram of the drive member as seen from the guide side. Fig. 1 is a left side view of the main parts, Fig. 7 is a configuration diagram of the operating member and scale plate seen from the right side of Fig. 1, Fig. 8 is a sectional view taken along the - line in Fig. 1 is a right side view of the main part of FIG. 1, FIG. 10 is a view corresponding to FIG. 6 showing another embodiment of the present invention, and FIG. 11 is a sectional view taken along the line -- in FIG. 1... Thread tension display device, 2a, 2b... Thread tension disc, 4... Thread tension knob, 5... Face plate, 13...
Drive member, 17...Male thread portion, 18...Thread tension nut, 19...Coil spring, 22...Guide, 24, 34...Operating member, 25...Engagement pin, 29...Scale plate, 31... ...Display window, 32...
Pointer, 33...display means.

Claims (1)

[Scope of Claim for Utility Model Registration] 1 a. A pair of thread tension discs that clamp the thread, b. A thread tension knob that adjusts the thread clamping pressure of both thread tension discs by rotating more than one rotation, and c. This thread. a driving member that rotates more than one revolution in conjunction with the adjustment knob and has a spiral guide centered on the center of rotation; an operating member that moves relative to the sewing machine; e display means that is formed between the operating member and a fixed part of the sewing machine and displays the adjustment state of the thread tension by relative movement of the operating member with respect to the fixed part; A sewing machine thread tension display device featuring: 2. The thread tension display device for a sewing machine according to claim 1, wherein the operating member is formed of a swinging member that swings as the drive member rotates. The thread tension display device for a sewing machine according to claim 1, wherein the actuating member is formed of a reciprocating member that reciprocates as the driving member rotates. The thread tension of a sewing machine according to claim 1 of the patent registration claim, wherein the display means is composed of a scale or a pointer provided on the operating member and a pointer or scale provided on a fixed part of the sewing machine. Display device.