JP2985257B2 - sewing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a sewing machine in which a lower thread is led out from a lower thread bobbin accommodated in a lower thread bobbin accommodating section provided in a bed portion. About.

(Prior Art) For example, in a household sewing machine, as shown in FIG. 10, a metal needle plate 3 is provided on an upper surface of a bed portion 1 of the sewing machine so as to face a sewing needle 2. The needle plate 3 is formed with a needle hole 4 through which the sewing needle 2 is inserted and a hole 5 for operating a feed dog, and a bobbin bobbin located in front of the needle hole 4 and opened and closed by a lid 6. An accommodation port 7 is formed.
Although not shown, a horizontal shuttle mechanism is provided in the bed portion 1 below the needle plate 3. The horizontal shuttle mechanism includes an outer shuttle having a blade point and rotating in the horizontal direction in synchronization with the vertical movement of the sewing needle 2, and a bed 1 in the outer shuttle.
The lower thread bobbin accommodating section and the tension generating section are provided in the inner shuttle so as to face the accommodation port 7. Further, as shown in FIG. 11, it is located on the upper surface of the bed 1 to the left of the needle plate 3,
A cutter 8 is provided.

In setting a new lower thread 9 before starting the sewing operation in such a sewing machine, the user firstly sets
The bobbin thread bobbin 10 (see FIG. 10) is fitted into the lower thread bobbin accommodating section of the inner hook through the accommodation port 7, and the bobbin thread 9 pulled out from the bobbin thread bobbin 10 is passed through the tension generating section. At this time, the leading end of the lower thread 9 is drawn out from the tension generating portion by a certain length. Next, the sewing needle 2 is moved up and down once by rotating a pulley (not shown) by hand, so that the lower thread 9 below the needle plate 3 is scooped by the upper thread and pulled out from the needle hole 4 upward. To The cutter 8 is used to cut off the leading end of the bobbin thread 9 pulled out from the needle hole 4 if necessary, if necessary, as shown in FIG. The lower thread 9 can be cut by pulling the tip side upward while pressing the base side of the lower thread 9 with a finger. Thus, the setting operation of the lower thread 9 is completed, and the sewing operation can be started.

(Problems to be Solved by the Invention) However, when setting the lower thread 9 as described above, particularly when pulling the lower thread 9 upward from the needle hole 4, the pulley is held while holding the tip of the upper thread with one hand. Since relatively complicated work such as rotation has to be performed, the work has been troublesome as a whole.

Actually, even if the lower thread 9 is not pulled out from the needle hole 4 upward, if the lower thread 9 has been pulled out from the tension generating portion for a predetermined length or more, the upper thread is lowered at the first stitch of the sewing start. By scooping the thread 9, sewing can be performed as it is.

However, when sewing is started without pulling out the lower thread 9 from the needle hole 4 as described above, if the length of the lower thread 9 pulled out from the tension generating portion is too short, the lower thread 9 is moved to the first stitch. Does not reach the needle hole 4 and a seam cannot be formed. Conversely, if the length of the bobbin thread 9 pulled out from the tension generating section is too long, the excess end of the bobbin thread 9 at the second needle forms a loop due to laying, causing troubles such as entanglement with the shuttle. There is a possibility that it will be.

In this regard, the lower thread 9 is set so as to pass through the needle hole 4 as described above, and if the lower thread 9 pulled out from the needle hole 4 is too long, the excess portion is cut off by the cutter 8. If this is done, the lower thread 9
Can be set with an appropriate drawing length. Therefore, in order to surely pull out the lower thread 9 by a length suitable for the sewing operation, the conventional method also has to perform a troublesome operation of pulling the lower thread 9 upward from the needle hole 4.

The present invention has been made in view of the above circumstances, and its purpose is to facilitate the work of setting the lower thread and to appropriately set the length of the lower thread pulled out from the tension generating portion at that time. It is to provide a sewing machine that can do.

[Structure of the Invention] (Means for Solving the Problems) In the sewing machine of the present invention, a cutting blade is provided on a bed portion, and a lower thread guided through a tension generating section is guided through a storage port to a cutting blade through a path of a predetermined length. A guide portion having a holding space having a side edge portion and a bottom that smoothly curves to the vicinity of the cutting blade inside the bed portion, and is located at least above the lower thread at the time of cutting the lower thread and held by the lower surface thereof A covering member constituting a ceiling of the space is provided, and the bobbin thread is pressed against the cutting blade by an operation of pulling the leading end side while the bobbin thread is guided by the guide portion, and the bobbin thread is cut off. The present invention is characterized in that the tensile force acting on the tension generating portion side of the lower thread by the cutting blade at the time of cutting is set to be smaller than the maximum static friction of the tension generating portion.

(Operation) According to the above means, the user guides the bobbin thread through the tension generating section to the cutting blade through the storage port to the cutting blade, and pulls the lower thread in this state, thereby cutting the bobbin thread into the cutting blade. Can be pressed and cut. In this case, the guide section guides the bobbin thread through a path of a predetermined length, so that the bobbin thread can always be set in a state where a fixed length is pulled out from the tension generating section. The bobbin thread is led out to the cutting blade through the storage port, so to speak, it is not necessary to pass through the needle hole, and the pulling blade acting on the tension generating portion side of the bobbin thread by the cutting blade at the time of bobbin thread cutting. Since the force is smaller than the maximum static friction of the tension generating section, there is no need to hold down the base side of the lower thread, and the lower thread can be easily cut using the resistance of the tension generating section. .

Moreover, at the time of this cutting, the bobbin thread is less likely to be entangled by being contacted and guided between the curved side edge and the bottom of the holding space and the lower surface of the covering member serving as the ceiling, and a reliable stitch can be expected from the first stitch.

Example An example of the present invention will be described below with reference to FIGS.

First, FIG. 5 shows the entire main body 11 of the sewing machine according to the present embodiment. Here, the main body 11 of the sewing machine is integrally provided with an arm 13 above a bed 12. A needle bar 15 on which a sewing needle 14 is mounted is provided at a distal end of the arm portion 13. The needle bar 15 is moved up and down by a drive mechanism (not shown). On the other hand, a metal needle plate 16 as shown in FIGS. 1 to 4 is provided on the upper surface of the bed portion 12 so as to face the needle bar 15. The needle plate 16 has a needle hole 16a through which the sewing needle 14 penetrates and a plurality of long holes 16b for operating a feed dog (not shown). A lower thread bobbin accommodating port 17 which is opened in a shape is formed. The housing opening 17 is opened and closed by a transparent slide lid 18 which is slidably inserted in the front and rear slide grooves 17a. In addition, this slide lid
In the closed state, as shown in FIG. 3, a minute gap is formed between the leading edge of the slide lid 18 and the inner edge 17b on the back side of the storage port 17. ing.

A cloth feed mechanism (not shown) for driving the feed dog in synchronization with the vertical movement of the needle bar 15 is provided in the bed portion 12, and the cloth feed mechanism is provided below the accommodation port 17 of the needle plate 16. A horizontal shuttle mechanism 19 which is located at a position and performs a sewing operation in cooperation with the sewing needle 14 while supplying a lower thread is provided.
As shown in FIG. 4, the horizontal shuttle mechanism 19 includes an outer shuttle 20 having a sword point 20a and rotating in the horizontal direction in synchronization with the vertical movement of the needle bar 15, and a bed portion in the outer shuttle 20. It comprises an inner pot 21 and the like provided in a detented state with respect to 12.
The inner hook 21 is provided with a cylindrical container-shaped lower thread bobbin storage section 22 having a shaft portion 22a, facing the lower thread bobbin storage port 17, and further provided on the front side of the lower thread bobbin storage section 22. A tension generator 23 is provided on the inner wall. Although not shown in detail, the tension generating portion 23 is configured by attaching a thread tension plate 23a and a thread tension spring 23b, both of which are arc-shaped, in an overlapping state. On the other hand, a pressing plate 24 made of, for example, plastic is attached to the lower surface of the needle plate 16 at the position of the accommodation port 17. The holding plate 24 is
It has a circular opening corresponding to the lower thread bobbin housing part 22,
The inner shuttle 21 is set in a state in which lifting and the like are prevented by the pressing plate 24. With this, the lower thread bobbin 26 formed by winding the lower thread 25 with the slide lid 18 opened is provided.
(See FIG. 4) is detachably fitted into the lower thread bobbin accommodating section 22 through the accommodating port 17. At this time, the lower thread bobbin 26 is
And is accommodated so as to be rotatable around the shaft portion 22a. The bobbin thread 25 led out of the bobbin bobbin 26 accommodated is passed between the thread tension plate 23a and the thread tension spring 23b of the tension generating section 23, and is appropriately pulled out by a frictional force therebetween. Resistance is given.

The horizontal shuttle mechanism 19 configured as described above is
Is rotated in the direction of arrow A (see FIG. 4) around the outer periphery of the inner hook 21, and a loop of an upper thread (not shown) formed below the needle hole 16 a is captured by the sewing needle 14 with the blade point 20 a. The thread loop is passed through the inner hook 21 and entangled with the lower thread 25 led out from the tension generating part 23, whereby a seam is formed.

Now, the needle plate 16 is provided with a thread cutting portion 27 for cutting the lower thread 25. As shown in FIG. 4, the thread cutting portion 27 is configured by arranging, for example, a plastic plate-shaped covering member 29 in a concave portion 28 formed in the needle plate 16.

That is, as shown in FIG. 4, the concave portion 28 is formed at a position on the left side of the needle hole 16a so as to be continuous with the inner edge portion 17b on the far side of the accommodation port 17. Further, the right inner edge of the concave portion 28 extends so as to gradually curve to the left toward the back. On the other hand, as shown in FIG. 6, the cover member 29 has a thin portion 29b integrally to the right of the thick portion 29a, and is formed in a stepped shape on the back side. The cutting blade 30 is mounted horizontally so that the cutting edge 30a faces rearward so as to be sandwiched between the tip portions of the thick portion 29a. The left edge of the thick portion 29a has a shape that matches the left inner edge of the recess 28, and the curved right edge of the thin portion 29b has a shape that is smaller than the curved shape of the right inner edge of the recess 28. It has a curved shape with a small turning radius. The cover member 29 is attached to the needle plate 16 by screwing a screw 32 (see FIG. 4) from below through a hole 28a formed in the concave portion 28 into a nut member 31 embedded and fixed in the thick portion 29a. ing. Thereby, between the curved right inner edge of the concave portion 28 and the curved right edge of the cover member 29, the cutting blade 3 is moved from the left side portion of the deeper inner edge 17b of the storage opening 17 to the cutting blade 3.
Guide groove with a bottom extending in a curved shape toward the cutting edge 30a of 0
33 are formed. As shown also in FIG. 7, a holding space 34 is formed between the recess 28 over the entire lower surface of the thin portion 29b so that the right side communicates with the guide groove 33 and is recessed to the left. That is, the holding space 34 has the concave portion 28 in which the covering member 29 is disposed as a bottom surface, and the left edge portion is the guide groove 33.
Is formed so as to extend straight from the open end of the cutting blade 30 to the cutting edge portion of the cutting blade 30, and the right side edge is close to the cutting blade 30 and forms a gentle curved shape which also serves as the right inner edge of the concave portion 28. The holding space 34 has a bottomed space shape that is located inside the bed portion 12 and communicates with the guide groove 33, and the lower surface of the thin portion 29b of the covering member 29 constitutes a so-called ceiling portion of the holding space 34. doing. The guide groove 33 and the holding space 34 constitute a guide section 35 according to the present invention.
At this time, the upper surface of the cover member 29 is a flat surface substantially flush with the upper surface of the needle plate 16, and the cutting blade 30 is provided at a position slightly lower than the surface.

After the lower thread bobbin 26 is set in the lower thread bobbin accommodating section 22 and the lower thread 25 is passed through the tension generating section 23 by the thread trimming section 27 as described above, the lower thread 25 is suitable for starting a sewing operation. The leading end can be cut in a state where only a short length is pulled out. That is, as shown in FIG. 1, the lower thread 25 led upward from the accommodation port 17 through the tension generator 23
The lower thread 25 is pressed against the cutting edge 30a of the cutting blade 30 by pulling the front end of the cutting blade 30 toward the cutting blade 30 in a state where it is guided to the cutting blade 30 by the guide groove 35. Be cut off. At this time, the guide groove 35 is
The lower thread 25 is always guided along a path of a predetermined length from 23 to the cutting blade 30. Here, the length l of the bobbin thread 25 guided and cut by the guide section 35 from the tension generating section 23 to the tip is a distance a from the tension generating section 23 to the needle hole 16a (seam).
(For example, 38 mm, see FIG. 2), the needle plate 1 of the blade point 20a of the outer hook 20
Assuming that the depth dimension from 6 is b (for example, 10 mm, see FIG. 9), a <l <a + 2b is set. In this embodiment, the thread cutting portion 27 is set so that 38 mm <l <58 mm, and the dimension l is, for example, about 48 mm.
It constitutes.

When cutting the lower thread 25, the lower thread is
The tensile force acting on the tension generating portion 23 side of the tension generating portion 25
It is set to be less than the maximum static friction of 23. In other words, as shown in FIG. 1, when the leading end of the lower thread 25 is pulled toward the near side, the lower thread 25 is pulled by such a force that the lower thread 25 is not pulled out from the tension generating portion 23.
The so-called sharpness or the like of the cutting blade 30 is set so that the cutting blade 30 is cut by the cutting blade 30.

Next, an operation procedure for newly setting the lower thread bobbin 26 in the lower thread bobbin accommodating portion 22 and starting the sewing operation in the above configuration will be described.

First, the user removes the lower thread bobbin 26 from the accommodation port 17 and removes the lower thread bobbin 26 from the accommodation port 17 in a state where the slide lid 18 is removed.
And set it. Next, the bobbin thread 25 pulled out from the bobbin bobbin 26 is passed through the tension generating section 23, and the leading end thereof is inserted into the accommodation port.
Pull upward from 17. At this time, the lower thread 25 is drawn out longer. Then, as shown in FIG.
The lower thread 25 is pivoted to the left as indicated by the arrow B while pinching the leading end of the lower thread 25 and slightly pulling the lower thread above the needle plate 16. Then, the middle part of the lower thread 25,
First, the guide groove 33 is hooked on the opening end portion, and a portion from the hooked portion toward the distal end is gradually guided into the guide groove 33. At this time, the lower thread 25 enters the holding space 34 from the guide groove 33, as shown in FIG. 7, and finally moves from the tip of the guide groove 33 as shown in FIG. It is guided so as to pass straight through to the deep portion of the cutting edge 30a. In this case, the lower thread 25 is guided into the holding space 34 and held in a state where it is prevented from coming off.
There is no danger of falling out. After this, as described above,
By pulling the lower thread 25 toward the near side so as to be folded at the cutting blade 30, the lower thread 25 is pressed against the cutting edge 30 a of the cutting blade 30 and cut. Thus, as described above, the lower thread 25 is pulled out from the tension generating part 23 by a length of about 48 mm,
Its tip is truncated. At this time, the tension generator
Since the lower thread 25 can be cut by the cutting blade 30 with a force that does not pull out the lower thread 25 from 23, there is no need to hold the base side of the lower thread 25 below the cutting blade 30. The lower thread 25 can be easily cut by utilizing the same.

At the time of cutting the lower thread 25, the end thereof is in contact guide between a gentle inner curved portion of the concave portion 28 which is a side edge portion of the holding space 34 and the bottom surface, and furthermore, the lower surface of the covering member 29 constituting the ceiling. Therefore, there is little risk of entanglement, and furthermore, it is difficult for the upper surface of the cover member 29 and thus the upper surface of the bed portion 12 to slip out. There is little danger.

Thereafter, the slide cover 18 is closed, and the bed 12 (the needle plate 1) is closed.
6) Set a work cloth (not shown) on the top and drive the sewing machine. Then, at the first stitch, the sewing thread 14 and the horizontal shuttle mechanism 19 cooperate to scoop the lower thread 25 that has been led out while giving an appropriate pull-out resistance from the tension generating section 23 by the cooperation of the upper thread loop. Thus, the sewing is performed. in this case,
The bobbin thread 25 is always guided by a guide section 35 along a path of a predetermined length and is cut.
mm) is larger than the distance a (38 mm) from the tension generating part 23 to the needle hole 16a (seam), so that the lower thread 25 can sufficiently reach the needle hole 16 at the first stitch, and the seam is formed reliably. can do. Since the lead length dimension 1 of the lower thread 25 is smaller than the length (58 mm) obtained by adding twice the depth dimension b (10 mm) of the point 20a from the needle plate 16 to the dimension a, A loop is formed below the needle plate 16 due to the laying of the surplus lower thread 25, and there is no occurrence of a trouble such that the lower thread loop is picked up and entangled by the sword tip 20a.

In addition, during this sewing operation, most of the thread cutting portion 27 except for the guide groove 33 is covered with the covering member 29 which is flush with the needle plate 16, so that the thread cutting portion 27 is smoothly caught without being caught. The work cloth can be sent to the cutting blade 30
Is provided at a position one step lower than the upper surface of the needle plate 16, so that the safety is excellent.

As described above, according to the present embodiment, the operation of setting the lower thread 25 is performed by passing the lower thread 25 through the tension generating section 23, and then pulling the lower thread 25 above the accommodation port 17 and turning the same through the guide groove 33, This is done by pulling it toward you and cutting it with the cutting blade 30. In this case, the guide portion 35 always guides the bobbin thread 25 to the cutting blade 30 along a path of a predetermined length, and the bobbin thread 25 is cut at a lead length l suitable for starting the sewing operation. ing. Therefore, unlike the conventional operation in which the lower thread 9 is pulled out from the needle hole 4 upward, the need to pass through the needle hole 16a is eliminated, and the setting of the lower thread 25 can be performed by an extremely simple operation. In addition, the length of the lower thread 25 from the tension generating portion 23 is not too long or too short, and the sewing operation can be started without any trouble. . Then, when cutting the lower thread 25 with the cutting blade 30, it is not necessary to hold down the base side of the lower thread 25 than the cutting blade 30, and the lower thread can be easily operated with only one hand using the resistance of the tension generating unit 30. Since 25 can be cut, the lower thread 9
The operation of cutting the lower thread 25 is simpler than that of the conventional method in which the lower side is pressed with the finger of one hand and the lower thread 9 is pressed against the cutter 8 with the other hand to cut.

In addition, in the present embodiment, in particular, the guide portion 35 is constituted by the guide groove 33 that extends in a curved manner and the holding space 34 that communicates with the guide groove 33 and holds the lower thread 25 in a retaining state. A series of extremely smooth operations, such as turning to the left and then pulling forward while slightly pulling the needle plate 16 in the depth direction above the needle plate 16, cut the lower thread 25 while being guided by the guide portion 35. In addition to this, there is little possibility that the end of the lower thread 25 immediately after the cutting is entangled, which is effective in securing an appropriate stitch from the first stitch at the start of sewing.

Further, in the present embodiment, the cover member forming the guide groove 33
Since the upper surface of 29 is flush with the needle plate 16, the work cloth can be smoothly fed, and the cutting blade 30 is provided at a position one step lower than the upper surface of the needle plate 16, so that the safety is excellent. Such advantages can be obtained.

The present invention can be implemented with appropriate modifications without departing from the scope of the invention.

[Effects of the Invention] As is apparent from the above description, according to the sewing machine of the present invention, the operation for setting the lower thread is facilitated,
At this time, there is an excellent effect that the length of pulling out the lower thread from the tension generating portion can be made appropriate.

[Brief description of the drawings]

1 to 9 show one embodiment of the present invention. FIG. 1 is a top view of a main part, FIG. 2 is a top view of a main part showing a state different from FIG. FIG. 4 is a perspective view of a needle plate, FIG. 4 is an exploded perspective view of a horizontal shuttle mechanism, FIG. 5 is a perspective view of a sewing machine main body, FIG. 6 (a) is a perspective view of a cover member, and FIG. FIG. 7 is a perspective view from the back side of the covering member.
FIG. 8 is an enlarged top view of a cutting blade portion, and FIG. 9 is a vertical side view showing a positional relationship between a needle plate and an outer shuttle along a line. 10 and 11 show a conventional example. FIG. 10 is a perspective view of a main part, and FIG. 11 is a perspective view of a main part showing a state of cutting a lower thread. In the drawing, 12 is a bed portion, 16 is a needle plate, 16a is a needle hole, 17 is a storage port, 19 is a horizontal hook mechanism, 20 is an outer hook, 20a is a sword point, 21 is an inner hook, and 22 is a lower thread bobbin receiving section. , 23 is a tension generating section, 24 is a presser plate, 25 is a bobbin thread, 26 is a bobbin bobbin, 27 is a thread cutting section, 28 is a concave section, 29 is a covering member, 30 is a cutting blade, 33 is a guide groove, and 34 is The holding space 35 indicates a guide.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 53-106146 (JP, U) JP-B 55-20876 (JP, B2) JP-B 61-10631 (JP, Y2) JP-B 61-106 8852 (JP, Y2) Jiko 56-54946 (JP, Y2) (58) Field surveyed (Int. Cl. ⁶ , DB name) D05B 65/00-65/02

Claims (1)

(57) [Claims] 1. A lower thread bobbin is detachably accommodated in a lower thread bobbin accommodating section provided in a bed section through an accommodation port on an upper surface of the bed section. In a configuration in which the lower thread is pulled out by the frictional force through a tension generating section provided in the storage section, a cutting blade provided in the bed section and a lower thread led out through the tension generating section are provided. A guide portion having a holding space having a side edge portion and a bottom, which is guided inside the bed portion by the path of a predetermined length through the accommodation port to the cutting blade, and has a gently curved side edge reaching the vicinity of the cutting blade inside the bed portion; A cover member that is located above the lower thread and constitutes a ceiling of a holding space at the lower surface thereof, and the lower thread is pulled by an operation of pulling the leading end of the lower thread while being guided by the guide section. The cutting blade is pressed against the cutting blade to enable the cutting, and the tension force acting on the tension generating unit side of the lower thread by the cutting blade at the time of cutting the lower thread is smaller than the maximum static friction of the tension generating unit. A sewing machine characterized by being set so as to be.