JP2985256B2 - 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 domestic sewing machine, when starting a sewing operation, a lower thread bobbin is accommodated in an inner hook, and a lower thread pulled out from the lower thread bobbin is provided in the inner hook. It is necessary to pass the lower thread through the tension generating section, and to draw the lower thread out of the required length from the tension generating section.

In this case, in the past, the lower thread was pulled upward from the needle hole of the needle plate to secure the required lead-out length.
In recent years, as shown in FIG. 10, a sewing machine provided with a lower thread cutter 3 on the upper surface of a bed portion 1 of a sewing machine, which is located on the left side of a needle plate 2, is provided. In this device, the lower thread 5 that has passed through a tension generating unit (not shown) is directly drawn upward from a lower thread bobbin accommodating port 4 provided on the front side of the needle plate 2 in a state where the lower thread 5 has been drawn out in advance. While holding the base of the lower thread 5 with a finger, the tip of the lower thread 5 is pulled so as to press the middle part of the lower thread against the lower thread cutter 3. It can be set. Thus, the setting of the lower thread 5 is completed without pulling out the lower thread 5 from the needle hole 2a of the needle plate 2, and when the driving of the sewing machine is started in this state, the sewing needle moves up and down. As a result, the upper thread scoops the lower thread 5 and becomes stitched, whereby a seam is formed on the work cloth and sewing is performed.

(Problems to be Solved by the Invention) However, as described above, the lower thread 5 is
In the case of cutting with, there is a disadvantage that a relatively troublesome operation using both hands such as holding the base side of the lower thread 5 with one hand and pulling the tip side with the other hand has to be performed. Further, since the lower thread 5 is pressed, if the slack of the lower thread 5 is large in a portion from the pressed position to the tension generating section, the length of the lower thread 5 after being cut out from the tension generating section is reduced. May be unnecessarily long.

Therefore, as shown in Japanese Patent Application No. 1-275374, filed by the present applicant, a sewing machine having a guide groove for guiding a lower thread to a cutting blade has been developed. As shown in FIGS. 11 and 12, the needle plate 2 has a bottomed guide groove 7 extending from the lower thread bobbin accommodating port 4 toward the cutting blade 6 so as to be curved leftward. It is formed. According to such a configuration, when the lower thread 5 pulled out upward from the storage port 4 through the tension generating section 8 is pinched at its tip and turned slightly to the left above the needle plate 2 and turned leftward. The middle part of the lower thread 5 is first hooked on the open end of the guide groove 7, and subsequently the guide groove 7 is sequentially moved from the hooked portion toward the distal end.
If guided inside, it is naturally guided to the cutting blade 6. In this case, since the guide groove 7 is curved and extends, with one hand,
Moreover, the bobbin thread 5 can be guided to the cutting blade 6 and cut by the smooth operation, and can be cut to a constant length by the guide groove 7 at all times.

However, in this case, when the lower thread 5 is swiveled to the left and passed through the guide groove 7 as described above, if the force for pulling the lower thread 5 to the left is too large, the lower thread 5 is There was a disadvantage that it deviated from 7. For this reason, there arises a problem that the lower thread 5 may not be cut well by one operation, and further improvement in reliability of operation is demanded.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sewing machine capable of facilitating the operation of setting a lower thread and improving the reliability of the operation. To offer.

[Structure of the Invention] (Means for Solving the Problems) In the sewing machine of the present invention, a cover member is disposed in a concave portion formed on an upper surface of a bed portion, a holding space is formed on a lower surface of the cover member, and a bed portion is formed. A cutting groove is provided, and a guide groove is provided on the upper surface of the bed portion, which communicates with the holding space, continuously extends from the storage port toward the cutting blade, and guides a lower thread derived from the storage port to the cutting blade, The holding space is characterized in that the bobbin thread passed through the guide groove is held in a state where it cannot be pulled out upward.

Further, it is desirable that the cover member is made of plastic and has a stepped shape on the lower surface to form a holding space between the cover member and the recess on the upper surface of the bed.

Furthermore, it is preferable that the holding space communicates with the opening along the direction in which the guide groove extends in a curved shape.

(Operation) According to the above-described means, the lower thread passing through the tension generating portion can be guided to the cutting blade through the storage port by the guide groove continuously extending from the storage port toward the cutting blade.
In this case, since the holding space communicating with the guide groove is formed on the lower surface side of the covering member, the bobbin thread is held by the holding space in a state where it cannot be pulled out upward, and in this state, the leading end side of the bobbin thread is pulled. Thereby, the lower thread can be pressed against the cutting blade and easily cut with one hand. In addition, since the lower thread after cutting in the holding space hardly comes out to the upper surface of the bed portion and does not enter the inside of the bed portion, the lower thread is less likely to be entangled with the movable member above the bed portion and the movable member inside the bed portion, The bobbin thread setting operation at the start of sewing is easy and reliable.

In this case, if the covering member forming the holding space is made of stepped plastic, there is an advantage that the lower thread slides well and can be easily manufactured.

Furthermore, by making the holding space open and open along the curved shape of the guide groove, the bobbin thread derived from the storage port can be easily inserted into the holding space by passing it through the guide groove so as to be hooked. With a simple operation, the retaining state can be ensured, and further improvement in workability can be expected.

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 curve leftward 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 the lower surface is formed in a stepped shape. And the thick part
The cutting blade 30 is mounted horizontally with the cutting edge 30a facing backward so as to be sandwiched between the distal end portions of the cutting blade 29a. The left edge of the thick portion 29a has a shape corresponding to the left inner edge of the recess 28, and the right edge of the thin portion 29b has the shape of the recess 28.
Has a smaller radius of curvature than the curved shape of the right inner edge portion. The covering member 29 includes a thick portion 29a.
A screw 32 is screwed into a nut member 31 embedded and fixed from below through a hole 28a formed in the concave portion 28 from below, and the nut member 31 is attached to the needle plate 16. Thus, between the curved right inner edge of the concave portion 28 and the curved right edge of the cover member 29, continuous from the left side portion of the inner edge 17b of the accommodation port 17 toward the cutting edge 30a of the cutting blade 30. A guide groove 33 having a bottom and extending in a curved shape is 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 a thick portion 29 with the concave portion 28 in which the covering member 29 is provided as a bottom surface.
The left edge portion having a stepped portion at the boundary between a and the thin portion 29b is formed so as to extend straight from the open end of the guide groove 33 to the cutting edge 30a of the cutting blade 30, and the right edge is The holding space 34 has a curved shape reaching the vicinity of the cutting blade 30 and also serving as the right inner edge of the concave portion 28, so that the holding space 34 is located inside the bed portion 12 and communicates with the opening along the curved extending direction of the guide groove 33. It has a bottomed space shape. 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 positioned at a position slightly lowered from that 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
Is guided to the cutting blade 30 by the guide groove 33 and the holding space 34, and the leading end thereof is folded back at the cutting blade 30 portion and pulled toward the near side, so that the lower thread 25 is It is pressed by 30a and cut. At this time, guide groove 33
The holding space 24 always guides the lower thread 25 along a path of a predetermined length from the tension generating section 23 to the cutting blade 30. Here, the length l from the tension generating portion 23 to the tip of the lower thread 25 to be cut
Is the distance from the tension generating portion 23 to the needle hole 16a (seam) (for example, 38 mm, see FIG. 2).
When the depth dimension from the needle plate 16 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.
Is composed.

Further, when cutting the lower thread 25, as shown in FIG. 1, when the tip of the lower thread 25 is pulled toward the near side, the lower thread 25 is pulled with such a force that the lower thread 25 is not pulled out from the tension generating portion 23. So that the lower thread 25 is cut by the cutting blade 30,
The so-called sharpness or the like of the cutting blade 30 is set.

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 previously drawn out longer. Then, as shown in FIG. 2, the lower thread 25 is pulled to the left as indicated by an arrow B while grasping the tip of the lower thread 25 that has been led out, and slightly pulling the lower thread above the needle plate 16. Turn. Then, the middle part of the lower thread 25 is first hooked on the opening end of the guide groove 33, and the portion from the hooked portion toward the distal end gradually becomes the guide groove.
Guided into 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, so that the guide groove
There is no danger of getting out of 33. Thereafter, as described above, the lower thread 25 is pulled toward the near side so as to be folded at the cutting blade 30, whereby the lower thread 25 is pressed against the cutting edge 30 a of the cutting blade 30 and cut. With this, as described above, the lower thread 25
The tip is cut off in a state where a length of about 48 mm is pulled out from the tension generating part 23. At this time, the lower thread 25 is cut by the cutting blade 30 by pulling the lower thread 25 with such a force that the lower thread 25 is not pulled out from the tension generator 23.
It is not necessary to hold the base side of the cutting blade 30 than the cutting blade 30, and the lower thread 25 can be easily cut with one hand using the resistance of the tension generating part 23.

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, by the cooperation of the sewing needle 14 and the horizontal shuttle mechanism 19, the loop of the upper thread scoops out the lower thread 25 which is led out while being given appropriate pull-out resistance from the tension generating part 23. The sewing is performed in view of this. In this case, since the lead length l (48 mm) of the bobbin thread 25 is larger than the distance a (38 mm) from the tension generating section 23 to the needle hole 16a (seam), the lower thread 25 is And the seam can be reliably formed. 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 pulling out the lower thread 25 passing through the tension generating portion 32 above the accommodation port 17 and turning the guide groove so as to be curved.
A series of extremely smooth operations with one hand, such as passing through 33, then pulling forward and cutting with the cutting blade 30, can be performed. Further, at this time, the holding space 34 is provided along the direction in which the guide groove 33 extends in a curved shape so as to communicate with the opening, and holds the lower thread 25 in a retaining state, so that the lower thread 25 easily enters the holding space 34, and Unlike the conventional bobbin thread 5 as shown in FIG. 11, which is likely to come off from the guide groove 7, the bobbin thread 25 is guided while being held in a state where it is prevented from coming off. Work can be performed reliably.

Moreover, the lower thread 25 after the cutting is held in the holding space in the same manner as before the cutting.
34, the guide groove 33 is curved, and the bed space
The lower thread does not easily get out of the upper surface of the bed portion 12 and is prevented from entering the inside of the bed portion 12 by the bottom surface of the concave portion 28, so that the lower thread is entangled with the movable member above the bed portion 12 and the movable member inside the bed portion 12. There is little danger, making a series of setting work very easy, and a proper stitch is secured from the first stitch at the start of sewing.

Further, in the present embodiment, the lower thread 25 is always cut at the derived length l suitable for starting the sewing operation, so that the derived length of the lower thread 25 from the tension generating portion 23 is reduced. The sewing operation can be started without any trouble, without being too long or too short.

Furthermore, in the present embodiment, the cover member 29 for forming the guide groove 33 and the holding space 34 is made of plastic and has a stepped lower surface side, so that the lower thread 25 in the holding space 34 can slide smoothly. And it can be easily manufactured. Moreover, since the upper surface 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 safety is improved. The advantage of being superior is also obtained.

The present invention is not limited to the above embodiment,
For example, the holding space 34 may be configured by forming the cover member 29 as a flat plate and forming a step on the concave portion 28 side of the needle plate 16, and the cover member 29 may be made of metal and the cutting blade may be integrally formed. Various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As is clear from the above description, according to the sewing machine of the present invention, the operation for setting the lower thread can be facilitated, and the reliability of the operation is improved. It has an excellent effect that it can be performed.

[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. FIG. 10 is a perspective view of a main part showing a conventional example, and FIGS. 11 and 12 are a top view and a view corresponding to FIG. 8 of a main part showing another conventional example, respectively. 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 2 shows a holding space.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-74286 (JP, A) JP-A-53-106146 (JP, U) JP-A-56-58976 (JP, U) Patent 2819685 (JP, A) B2) Japanese Patent Publication No. 56-20876 (JP, B2) Japanese Patent Publication No. 41-19786 (JP, B2) Japanese Utility Model No. 61-10631 (JP, Y2) Japanese Utility Model No. 61-8852 (JP, Y2) −54946 (JP, Y2) (58) Fields investigated (Int. Cl. ⁶ , DB name) D05B 65/00-65/02 D05B 65/00-65/06

Claims (3)

(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, and a lower thread led out from the lower thread bobbin is accommodated in the lower thread bobbin. A cover member disposed in a concave portion formed on the upper surface of the bed portion; and a lower surface of the cover member and the concave portion. And a cutting blade provided in the bed portion, the cutting blade communicates with the holding space in the bed portion, and is continuously provided from the housing port to the cutting blade on the upper surface of the bed portion. And a guide groove for guiding the lower thread drawn out of the storage port to the cutting blade, and the holding space holds the lower thread passed through the guide groove in a state where the lower thread does not come off. The feature is that Sewing machine. 2. The sewing machine according to claim 1, wherein said cover member is made of plastic and has a stepped shape on a lower surface side thereof, and a holding space is formed between the cover member and a concave portion on an upper surface of the bed portion. 3. The guide groove is provided on the upper surface of the bed portion so as to extend in a curved state from the accommodation port toward the cutting blade, and the holding space is opened along a direction in which the guide groove extends in a curved shape. 3. The sewing machine according to claim 1, wherein the sewing machine is configured to communicate with the sewing machine.