JPH0519436B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is compatible with the sewing pattern in addition to the cloth to be sewn and the sewing thread to be sewn, and can set an appropriate thread tension by operating the selection operation section for each. It is related to sewing machines.

(Prior art) Sewing machines currently in general use use individual sewing conditions such as fabric, thread, pattern, feed amount, sewing method, and bobbin thread tension as data, and the sewing machine user adjusts the upper thread tension device to thread the upper and lower threads. Although there have been many proposals for automating the adjustment of the upper thread tension device, there are still no useful proposals regarding how to deal with the fabric and thread. It is.

(Problem to be solved by the invention) The type of fabric is determined step by step in advance, and sewing conditions are set based on the selection, and the upper thread tension is adjusted to the appropriate upper thread tension, and the intersection position of the upper thread and lower thread in the fabric is adjusted to suit the purpose of use. It is possible to adjust the thread tension to the heel position, but in addition to this, in order to prevent fabric shrinkage and thread jamming, the thread tension should be lowered overall for thin fabrics, and on the contrary, tightened for thicker fabrics, i.e., lower. It is necessary to set conditions including adjusting the thread tension, and it is also necessary to set the presser foot pressure appropriate for the type of fabric in terms of fabric shrinkage and feed.
In addition, in conventional sewing machines, stitch defects also occur when the fabric feed is stopped due to incorrect operation of the feed dog action disabling device, and the purpose of this sewing machine is to solve these and other problems in obtaining proper stitches. do.

(Means for Solving the Problems) In the present invention, in order to obtain appropriate stitches, the appropriate upper thread tension is determined by a selection device for the type of fabric, type of thread, and type of pattern, and a calculation process that calculates the output information from the operation. By providing a section and a section for setting the appropriate upper thread tension,
The bobbin thread tension is determined by setting the bobbin thread payout amount or bobbin thread tension corresponding to the fabric type, and by connecting this actuating unit and the fabric type selection device, the presser foot pressure is determined by the fabric type selection device and the presser foot that adjusts the presser foot pressure. The above-mentioned problems are solved by interlocking the pressure dial and by interlocking the feed dog disabling device with the cloth type selection device and displaying the display thereof.

(Function) With the above configuration, the cloth type, thread type, and pattern are displayed by operating the cloth type, thread type, and pattern type selection device, and furthermore, the appropriate upper thread tension is calculated by the calculation section, and the upper thread tension is adjusted. is set. Regarding the bobbin thread tension, depending on the fabric type selection, the bobbin thread payout amount or bobbin thread tension is set according to the fabric type. At the same time, the appropriate presser foot pressure is set by rotating the presser dial in conjunction with the cloth type selection.

(Example) An example of the present invention will be described in detail with reference to the drawings.
1 to 8 show a first embodiment of the present invention, and in FIG. 2, a pattern selection section 3, a cloth type selection section 4, and a thread type selection section 5 are provided on the surface 2 of the sewing machine frame 1. There are two selection sections, and the fabric type selection section 4 has an LED 6 that indicates the selection of lowering the feed dog by displaying "〓", an LED 7 which indicates thin material by displaying "Light", and a medium-weight material (regular) by displaying "Normal". LED indicating cloth)
8. LED 9 is provided to indicate thick material by displaying "hot", and these and presser foot pressure adjustment dial 10 are provided.
are electrically connected. As for the thread type, LED 11 indicates selection of fine thread by displaying "#100", LED 12 indicates selection of normal thickness thread by displaying "#50",
LED13 indicates thick thread selection by displaying “#30”;
LED indicating Katan thread selection by displaying "Katan"
14, and by pressing a yarn type selection button 15, selections can be made sequentially from the end. 16 is a pattern selection button.

Each of the above selection devices is connected to a thread tension calculation circuit that performs calculation processing.

The upper thread 17 is supplied to the needle through a pretensioner 18, a pressure plate 19 of an upper thread tension device, a thread folding portion 21 of a thread take-up cover 20, and a take-up thread 22. In Figure 3, 23 indicates upper thread tension.
It is a group of LEDs. 24 is the upper thread tension dial. 25
is a pointer, which is driven by the rotation of the upper thread tension dial.

Figure 1 shows the internal mechanism. Reference numeral 26 denotes a feed dog, and the feed dog is provided with a bridge portion 27 for reeling the bobbin thread 28. A lower shaft 37 is rotatably supported by a feed base 38 fixed to the sewing machine frame 1 in conjunction with a drive shaft (not shown) rotatably supported by the sewing machine frame 1. 43
is a feed shaft, which is rotatably supported by the feed base 38 parallel to the lower shaft 37. 35 is a vertical feed cam having a plurality of diameters and a plurality of eccentricities, and is fitted on the lower shaft 37, and has a key 3 attached to the lower shaft 37 inside as shown in FIGS.
The lower shaft 37 has a key groove 35a that fits into the lower shaft 37, and rotation is transmitted thereto so that the lower shaft 37 can move in the axial direction. A vertical feed arm 36 is fitted onto the feed shaft 43, is biased by the action of a spring 45, contacts the vertical feed cam 35, and rotates due to its eccentricity.
As shown in the figure, a feed base 4 to which the feed dog 26 is attached via rollers 41 attached to the upper and lower feed arms 36
It performs the vertical movement of 2. The vertical feed cam 35 includes a large cam portion 35b having an eccentric amount corresponding to the cloth type “hot” and “normal”, a small cam portion 35c having an eccentric amount corresponding to the cloth type “light”, and the lower shaft. 37, and the boundary between the large cam part 35b and the small cam part 35c is a tapered part 4 for facilitating axial movement with respect to the vertical feed arm 36 in contact with it.
0 is formed. Although the large cam portion 35b and the small cam portion 35c have different eccentricities, their outer diameters are set so that their maximum positions (as shown in Fig. 6, P) are the same. Feeding arm 3
6 have the same maximum inclination position, thereby keeping the uppermost position of the feed dog constant.

As shown in FIG. 5, the axial position of the vertical feed cam 35 is such that a driven lever 30, whose one end is pivotally mounted to the sewing machine frame, engages an upper cam portion 29 formed on a part of the presser foot pressure dial 10. A wire 31 is fastened to the other end of the driven lever 30. The wire 31 is connected to a vertical feed cam lever 34 whose one end is pivotally connected to the sewing machine frame 1 via intermediate gears 32 and 33.
It has been concluded. A spring 45 whose one end is fixed to the sewing machine frame 1 is engaged with the vertical feed cam lever 34, and is used to position the driven lever 30 that engages with the upper cam portion 29 of the presser adjustment dial 10 and the vertical feed cam lever 34. is being done.
The end surface of the vertical feed cam 35 is urged by a spring 46 and abuts and engages with the claw portion 34a of the vertical feed cam lever 34.

A lower cam 47 formed as a part of the presser foot pressure dial 10 is fitted into the sewing machine frame 1, and a presser bar 49 coaxial with the lower cam 47 and having a presser foot 48 at the bottom is fitted into the sewing machine frame 1. It fits loosely.
A presser spring 51 is installed between the presser bar plate 50 fixed to the presser bar 49 and the lower cam 47.
1 , a follower 53 is abutted and engaged with the lower cam 47 and has a protrusion 53 a that fits into a slide groove 52 a provided in a guide stand 52 fixed to the machine frame. A working end 55 of a slide volume 54 fixed to the guide stand 52 is fitted into a hole provided in the protrusion 53a, and the signal output of the slide volume 54 is transmitted through a fabric type LED circuit and a thread tension calculation circuit (both (not shown).

Next, the operation will be explained with reference to the block diagram of FIG. 8 and FIG. By rotating the presser foot pressure dial 10 against a thin cloth, the follower 53 that comes into contact with the lower cam portion 47 is restricted from rotating in the axial direction by the protruding portion 53a that fits into the slide groove 52a of the guide table 52. Moved. The protrusion 53a
A signal is outputted from the slide volume 54 to the cloth type LED circuit by the working end 55 that fits into the hole, and the cloth type LED lights up according to the output amount. When the follower 53 is in the upper position, the "light"
The fabric type LED 7 indicating `` is lit up, and a signal is output to the thread tension calculation circuit. Since the follower 53 is located above, the pressing force of the presser spring 51 between the follower 53 and the presser bar 50 is reduced, resulting in a low presser pressure.

Further, the position of the vertical feed cam 35 by the upper cam 29 of the presser foot pressure dial 10 is as shown by the dotted line in FIG. The vertical feed cam lever 34 is connected to the spring 4 through the vertical feed cam lever 34.
4, the small cam portion 35c of the vertical feed cam 35 is brought into a position where it engages with the vertical feed arm 36, and the rotation of the small cam portion 35c causes the vertical feed arm 36 to rotate as shown in FIG. The angle is β;
The roller 41 attached to the vertical feed arm 36
The feed table 42, to which the feed dog 26 is attached, moves up and down a little, and as a result, the amount of bobbin thread fed out by the bridge portion 27 of the feed dog 26 becomes large. The thread tension is set to low.

Regarding upper thread tension, in addition to selecting the cloth type, the LED is turned on by operating the thread type selection button 15 to select the thread type for the thread to be used, and this signal is output to the thread tension calculation circuit. In addition, by operating the pattern selection button 16 provided with a display pattern, the LED
is turned on to output a signal to the thread tension calculation circuit.

As a result, the thread tension calculation circuit performs calculations based on the output information of the cloth type, thread type, and pattern type.
The data is read from the storage section and the proper upper thread tension is displayed by lighting a part 23a of the upper thread tension display LED group 23 provided on the surface 2.

On the other hand, when the user rotates the upper thread tension dial 24 and aligns the pointer 25 with the lit LED 23a, an appropriate upper thread tension is set by the pressure plate 19 of the upper thread tension device.

Next, we will explain how to handle medium-weight cloth.

By rotating the presser foot pressure dial 10, the follower 53 that comes into contact with the lower cam portion 47 is located below the above-mentioned "light" display position, and the fabric type LED 8 indicating "normal" is displayed. When the light is turned on, a signal is output to the thread tension calculation circuit. Since the follower 53 is located lower than when "light" is displayed, the pressing force of the presser spring 51 between the follower 53 and the presser bar 50 increases, resulting in a medium presser pressure. Further, the vertical feed cam 3 is controlled by the upper cam portion 29 of the presser foot pressure dial 10.
5 is located at the upper cam 2 as shown by the solid line in FIG.
The driven lever 30 is in contact with a diameter of 9, and the vertical feed cam lever 34 is connected to the vertical feed arm 36 via the wire 31 and the large cam of the vertical feed cam 35 is biased by the spring 44. The portion 35b is in the engaging position, and as shown in FIG. 6, the rotation of the large cam portion 35b causes the vertical feed arm
The rotation angle becomes α, which reduces the vertical movement of the feed base 42 to which the feed dog 26 is attached via the rollers 41 attached to the vertical feed arm 36, thereby reducing the bridge portion 27 of the feed dog 26.
The bobbin thread payout amount is small, and the bobbin thread tension is set to be strong in accordance with the medium weight fabric selected.

Regarding upper thread tension, in addition to selecting the cloth type, the thread type LED is turned on by operating the thread type selection button 15 to select the thread type for the thread to be used, and this signal is output to the thread tension calculation circuit. Further, the user operates the pattern selection button 15 provided next to the displayed pattern to turn on the LED and output a signal to the thread tension calculation circuit. As a result, the thread tension calculation circuit performs calculations based on the output information of the cloth type, thread type, and pattern type, reads the data from the memory element, and displays the appropriate upper thread tension through the upper thread tension display LED provided on the surface 2.
This is displayed by lighting up part 23b of the group 23. In response, the user rotates the upper thread tension dial 24 to adjust the pointer 25 to the lighting LED 23b.
By adjusting the tension, an appropriate upper thread tension can be applied by the pressure plate 19 of the upper thread tension device.

Next, we will explain how to handle thick cloth.

The follower 5 comes into contact with the lower cam portion 47 by rotating the presser foot pressure adjustment dial 10.
3 is a position further below the above-mentioned "normal" display position, and the fabric type LED indicating "hot" lights up, and the follower 53 is located below the "normal" display position, so that the follower The pressing force of the presser spring 51 between the presser bar 53 and the presser bar 50 increases, and becomes strong presser pressure. Also, the vertical feed cam 35 is controlled by the upper cam 29 of the presser foot pressure adjustment dial.
As shown by the solid line in FIG. 5, the position is the same as in the case where the medium-thick material is selected as described above, and the vertical feed arm 36 is engaged with the large cam portion 35b of the vertical feed cam 35, and the vertical feed arm 36 is engaged with the large cam portion 35b of the vertical feed cam 35. The rotation angle of the feed dog 36 is α, the amount of bobbin thread fed out by the bridge portion 27 of the feed dog 26 is small, and the bobbin thread tension is set to be strong in response to thick cloth.

Next, selection of the lowered state of the feed dog will be explained. The follower 53, which rotates the presser foot pressure dial 10 and comes into contact with its lower cam portion 47, lowers the feed dog 26 when the "〓" is displayed at a position above the "Light" display position. LED6 indicating selection lights up.

Also, the upper cam 29 of the presser foot pressure adjustment dial 10
As shown in FIG. 5, the follower lever 30 comes into contact with the diameter of the upper cam 29, and the vertical feed cam lever 34 is moved via the wire 31 to the vertical feed arm 36 by the bias of the spring 44. The zero eccentricity position 35d of the vertical feed cam 35 becomes the engaged position, and as shown in FIG. 26 remains in a sunken position from the upper surface of the throat plate.

A second embodiment is shown in FIGS. 9 to 11. In this embodiment, as shown in FIGS. 9 and 10, the first
Unlike the above embodiment, the fabric type selection dial 56 is provided separately from the presser mechanism, and instead of displaying the appropriate upper thread tension, an upper thread tension device is used to automatically adjust the appropriate upper thread tension. 56 is linked to the bobbin thread payout amount adjustment mechanism as in the first embodiment.

There are three selection parts on the surface 2 of the sewing machine frame 1: a pattern selection part 3, a cloth type selection part 57, and a thread type selection part 5. The configuration is the same as the example, so it will be omitted. The cloth type selection section 57 has a dial shaft 67 rotatably supported on the machine frame 1, and an instruction line 56a outside the machine frame.
A cloth type selection dial 56 is fixed thereto. The fabric type selection dial 56 on the machine frame surface 2
Display 58 indicates the selection of lowering the feed dog by displaying "〓" around the , "Light" display 59 indicates the thin material, and "Normal" indicates the medium weight material (regular cloth). 60, a display 61 indicating "hot" indicating the thickness of the fabric type is clearly displayed, and the position of the fabric type selection dial 56 is determined by fitting the pin spring 63 and pin 64 into the hole 62 provided in the machine frame 1. A plurality of indentations 65 are provided on the back surface of the cloth type selection dial 56 at locations where the pins 64 come into contact, corresponding to the respective indications. The mechanism for adjusting the vertical movement of the feed dog 26 is the same as that of the first embodiment described above, and is omitted here, but the other end of the wire 66 fastened to the vertical feed cam lever 34 is fixed to the dial shaft 67. It is fastened to the feed switching arm 68. A rotary volume 69 is attached to the end of the dial shaft 67, and a signal output from the rotary volume 69 is input to a thread tension calculation circuit. Further, signal outputs from the thread type selection device 5 and pattern selection device 3 are also input to the thread tension calculation circuit.

Reference numeral 70 denotes an electromagnetic upper thread tension device, which is electrically connected to the thread tension calculation circuit, and has a structure in which the pressure applied to the two pressure plates 71 that sandwich the upper thread is variable depending on the amount of current applied thereto. It is something that you have.

Next, the operation will be explained based on FIG. For thin cloth, rotate the cloth type selection dial 56,
The indication line 5 of the cloth type selection dial 56 is displayed on the cloth type display "Light" 59 displayed on the surface 2 of the machine frame 1.
6a, the feed switching arm 68 fixed to the dial shaft 67 is rotated.
By rotating the vertical feed cam lever 34 via the wire 66 fastened to
Increase the vertical momentum of

As a result, the amount of bobbin thread fed out by the bridge portion 27 of the feed dog 26 becomes large, and the bobbin thread tension is set to be weak in accordance with the selected thin fabric type. The upper thread tension is determined by inputting a signal output from the rotation volume 69 to the thread tension calculation circuit by rotating the cloth type selection dial 56. Further, by operating the thread type selection button 15, the LED is turned on to select the thread type for the thread to be used, and this signal is output to the thread tension calculation circuit. To select a pattern, operate the pattern selection button 16 provided next to the displayed pattern to turn on the LED and output a signal to the thread tension calculation circuit. As a result, the thread tension calculation circuit performs calculations based on the output information from the cloth type, thread type, and pattern type selection sections.
Data is read from the storage section and a signal is output to the electromagnetic automatic upper thread tension device 70 so that the upper thread tension is properly adjusted.
The appropriate upper thread tension is set. In the case of medium-weight cloth or thick cloth in this embodiment, the feed dog lowering selection is performed by the cloth type selection operation as in the first embodiment, and the operation is the same, so the explanation will be omitted. .

A third embodiment is shown in FIGS. 12 to 14.

There are three selection parts on the surface 2 of the sewing machine frame 1: a pattern selection part 3, a cloth type selection part 4, and a thread type selection part 5. Since the configuration is the same as that of the embodiment, a description thereof will be omitted. The fabric type selection section 4 is provided with an LED 7 that indicates a thin fabric by displaying "Light", an LED 8 indicating a medium weight fabric (ordinary fabric) by displaying "Normal", and an LED 9 indicating a thick fabric by displaying "Hot". By pressing the cloth type selection button 83, the cloth type can be selected sequentially from the end, and the selection signal is connected to the thread tension calculation circuit. 23 is an upper thread tension display LED group. 24 is the upper thread tension dial. 25 is a pointer which is driven by the rotation of the upper thread tension dial. Figures 13 and 14 show the bobbin thread adjustment device;
A predetermined lower thread tension is set by adjusting the pressure on the lower thread tension spring 73 that presses the lower thread 28 between it and the lower thread tension stand 84.

The operating lever 77 is connected to a solenoid actuated by an electric signal from the cloth type selection device, and the rotating lever 81 is similarly connected to a step motor which is rotated by an electric signal from the cloth type selection device. The selection of the operating lever 77 is the first when there is no signal.
It faces the pin 78 of the cylinder 79 of the inner hook 72 at the position indicated by the two-dot chain line in FIG. 4 with a gap D for passing the needle thread loop therethrough. The inner hook 72 is a bobbin thread tension stand 8.
4 and the lower thread tension spring 73, and one end of a lever 76 that rotates about the lever pin 85 is in contact with the tip of the lower thread tension spring 73,
A small spring 86 is provided between this contact portion and the lever pin 85 so as to release the lever 76 from contact. The other end of the lever 76 is in contact with a ball 87 biased by a spring 75 fitted into the sliding cylinder 79. Reference numeral 80 is a stopper which is fitted into the inner pot 72 and slidable, and has a spring 88 inside thereof, and when there is no signal, its tip abuts against the cylinder 79 at the position indicated by the two-dot chain line in FIG.
The tip 81a of the rotating lever 81 has a gap B between it and the stopper pin 82 for passing the upper thread loop.
It is held open.

Next, the operation will be explained with reference to FIG. For thick cloth, selection is made by operating the cloth type selection button 83 to display "hot" and turn on the LED 9 indicating thick cloth. A signal resulting from this selection is output to the thread tension calculation circuit and lower thread tension adjustment circuit.
To adjust the upper thread tension, press the thread type selection button 1.
5, the thread type display LED is turned on to select the thread type for the thread to be used, and this signal is output to the thread tension calculation circuit. To select a pattern, operate the pattern selection button 16 provided next to the displayed pattern to turn on the LED, and the thread tension calculation circuit operates based on the output information from the fabric type, thread type, and pattern type selection sections. The calculation is performed, data is read from the storage section, and the appropriate upper thread tension is displayed by lighting a part 23a of the upper thread tension display LED group 23 provided on the surface 2. In response, the user rotates the upper thread tension dial 24 to cause the pointer 25 to turn on.
Appropriate upper thread tension is applied by the pressure plate 19 of the upper thread tension device by matching with the LED 23a. The bobbin thread is pressed in the direction of arrow A by the lighting of the LED displaying "hot" according to the fabric type selection and the signal output to the bobbin thread adjustment circuit, and the operating lever 77 is pushed in the direction of arrow A, pushing the pin 78, as shown in FIG. The cylinder 79 moves against the urging force of the spring 75 from the position shown by the two-dot chain line to the position shown by the solid line. At this time, the stopper 80 is moved to the position indicated by the solid line by the biasing force of the spring 88, and the position of the cylinder 79 is fixed. As a result, the pressure of the spring 75 on the lever 76 with the lever pin 85 as a fulcrum is greater than that of the small spring 86, and the lever 76 is rotated with the lever pin 85 as a fulcrum, thereby pressurizing the lower thread tension spring 73. Set the bobbin thread tension to "strong". In order to pass through the upper thread loop, the operating lever 77 pushes the cylindrical pin 78 to lock the cylinder 79, returns a little, and stops with a gap D between it and the cylindrical pin 49.

Next, in the case of a medium-weight item, by operating the cloth type selection button 83, a selection is made to display the cloth type of "normal" and turn on the LED 8 indicating the medium-weight item. A signal resulting from this selection is output to the thread tension calculation circuit and lower thread tension adjustment circuit. To adjust the upper thread tension, as in the case of thick materials, a signal is output to the thread tension calculation circuit by selecting the thread type and pattern type, and calculations are performed based on the output information and data is read from the storage section. The proper upper thread tension is displayed by lighting a part 23a of the upper thread tension display LED group 23 provided on the surface 2. The subsequent adjustments are the same. The adjustment of the bobbin thread tension is activated based on information from the fabric type selection, but for medium-weight fabrics, the bobbin thread tension should be at the same level as for thick fabrics, so the adjustment should be made at the same position as for the above-mentioned thick fabrics. Set the bobbin thread tension to "strong".

In the case of light fabrics, the fabric type button 83 is operated to display the fabric type of "light" and the LED 7 indicating light fabrics is selected to light up, and the output information from the thread type selection and pattern type selection is added to the thread tension calculation circuit. performs calculations, reads data from the storage section, and displays the appropriate upper thread tension by lighting up a part 23a of the upper thread tension display LED group 23 provided on the surface 2. Adjustment at this time is performed for thick and medium-sized materials. The same applies to thick materials.

To adjust the bobbin thread tension, the output signal from the cloth type selection device is input to the bobbin thread tension adjustment circuit, so that the operating lever 77 is pushed back in the direction opposite to arrow A by a connected solenoid. The rotation lever 81 is also rotated in the direction of arrow C by a step motor connected to the stopper pin 8.
2 to release the stopper 80, move the cylinder 48 back to the position indicated by the two-dot chain line, and release the spring 7.
Return the pressing force in step 5 to the initial state. In this state, the spring force of the small spring 86 acts stronger than the spring force of the spring 54 on the lever 76 with the lever pin 85 as a fulcrum, so the tip of the lever 76 is released from contact. Set the bobbin thread tension to "low".

(Effect) With the above configuration, the type of cloth, the type of thread,
By selecting the pattern type, the display for each selection and the automatic setting of the appropriate upper thread tension and lower thread tension corresponding to each selection information are obtained, and these and the setting of the appropriate presser foot pressure are obtained as a combination. Since countermeasures against seam defects such as seam shrinkage and seam elongation are also included, a more complete automatic thread tension sewing machine can be achieved.

In addition, the bobbin thread is adjusted by adjusting the bobbin thread payout amount, and the vertical amount of the feed dog that feeds out the bobbin thread is adjusted by using a top and bottom feed cam with a plurality of cam parts having different eccentricities, so that it can be adjusted to suit the type of fabric. In addition to the corresponding bobbin thread payout amount, the height of the feed dog was set to be constant at the top in this case, but it can be set to a value depending on the type of fabric.

In addition, the selection of lowering the feed dog, which may result in poor stitching due to an erroneous operation, is performed by the fabric type selection operation section, and the lowering of the feed dog is clearly indicated on the display, thereby making it possible to prevent erroneous operations.

[Brief explanation of the drawing]

The drawings relate to embodiments of the present invention, and FIG. 1 is a detailed view of the mechanism of the automatic thread tension sewing machine of the first embodiment, FIG. 2 is an external view, FIG. 3 is an enlarged view of a portion thereof, and FIG. FIG. 5 is a diagram of the lower thread adjustment mechanism, FIGS. 6 and 7 are explanatory diagrams of the vertical feed generating section, FIG. 8 is a block diagram of thread tension setting, and FIG. 9 is a diagram of the second embodiment. Fig. 10 is a detailed view of its mechanism, Fig. 11 is a block diagram of its thread tension setting, Fig. 12 is an external view of the third embodiment, Fig. 13 is a perspective view of its bobbin thread adjustment section, FIG. 14 is a partial sectional view of the same, and FIG. 15 is a block diagram of the thread tension setting, 4 and 56 are fabric type selection devices, and 10 is a presser foot pressure dial.

Claims (1)

[Claims] 1. It has a fabric type selection device and a calculation unit that calculates an appropriate upper thread tension based on the signal output from the selection device, and sets the upper thread tension based on the calculation result of the calculation unit.
Alternatively, the sewing machine that performs at least one setting of the bobbin thread tension based on the fabric type selection is characterized by having a presser foot pressure dial that adjusts the presser foot pressure in conjunction with the selection operation of the fabric type selection device. Automatic thread tension sewing machine.