JPS61238290A - Yarn cutter of sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a thread cutting device for a sewing machine that cuts upper and lower threads connected to a workpiece cloth at the end of sewing.

(Prior Art) In the conventional thread cutting device of this type of sewing machine, a fixed blade, a movable blade, and a pressing member are provided below the throat plate, and when the movable blade moves forward, the tip of the movable blade cuts the thread. The bobbin thread that is paid out from the upper thread loop and the bobbin is handled in the recess, and when the movable blade moves back, the thread hook formed following the tip thread handling section is attached to the fabric side limb of the upper thread loop and When the bobbin thread is captured, the thread hook is cut simultaneously by the cooperation of the cutting blade provided near the inner depth of the recess and the fixed blade, and after the cutting, the needle side limb of the needle thread loop is cut. The movable blade and the bobbin thread are pressed toward the movable blade by the pressing member and are held between them.

(Problems to be Solved by the Invention) However, in this conventional thread cutting device, the pressing member and the movable blade are not connected to each other when the needle side limb of the needle thread ring and the lower thread on the bobbin side are aligned after cutting. Therefore, when the needle side limb of the needle thread ring is later removed from between the pressing member and the movable blade by a wiper device, the bobbin thread is also removed from between the pressing member and the movable blade. Sometimes I would fall out. This phenomenon tends to occur when the upper thread is thicker than the bobbin thread, and if the next sewing is started with the bobbin thread clamped in this way, the first stitch will be reliably formed. There was a problem that it was not done.

Structure of the Invention (Means for Solving the Problems) The present invention has been made by focusing on the above-mentioned problems. A needle 5 that passes through the needle plate 2 of the incense stick and moves up and down in a supported state, and a thread ring catcher that is rotatably supported around one axis below the needle plate 2 and is attached to a part of its outer periphery. 10a, and a bobbin 12 that is housed in the outer hook 10 with the bobbin thread T2 wound therein. Trap 7
a fixed blade 13 provided below the throat plate 2 on one side of the vertical movement path of the needle 5; a fixed blade 13 movably disposed adjacent to the fixed blade 13; Yarn handling part 15a and its tip yarn handling part 15'a
The thread hook formed subsequently has a recess 15b and a cutting edge 15c located near the inner inner part of the recess 15b,
As the bobbin thread T2 unwound from the cloth side limb Tw of the upper thread thread ring TL and the bobbin 12 moves, the thread hook is moved to the recess 1.
5b, and a movable blade 15 for cutting at the same time by cooperation of the cutting blade part 15c and the fixed blade 13, and a needle thread ring TL located adjacent to the movable blade 15 after cutting. A pressing member 16 for pressing and holding the needle side limb Tn and the bobbin thread T2 toward the movable blade 15, and when cutting both the threads T1 and T2 as the movable blade 15 moves, the thread hook is The thread acts on at least one of the needle thread T1 and the bobbin thread T2 so that the needle side limb Tn of the needle thread ring TL captured by the recess 15b and the bobbin thread T2 on the bobbin 12 side are separated. In addition, means 18 are provided.

(Function) Therefore, in the thread cutting device of the present invention, the needle thread ring T
With the needle side limb Tn of L and the lower thread T2 on the bobbin 12 side being separated, both threads Tl and T2 are cut, and these threads 'l'l and 'l'2 are attached to the pressing member 16. Even if the needle side limb Tn of the needle thread ring TL is pulled out after that, the bobbin 1
The bobbin thread T2 on the second side is not pulled out, and the bobbin thread T2 on the second side is not pulled out.
2 remains pressed and held between the pressing member 16 and the movable blade 15, and the fourth stitch can be reliably formed when the next sewing starts.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to FIG. 1.2.

Now, this embodiment is embodied in a two-needle needle feed sewing machine, and as shown in FIG. Long hole 2a
is formed. A feed dog 4 is disposed within the bed portion la so as to be movable in four feeds so as to be able to move up and down onto the work cloth support surface 3 of the bed portion la through the elongated hole 2a of the throat plate 2.
A pair of needle insertion holes 4a are formed approximately in the center thereof.

Above the feed dog 4, a pair of needles 5 is supported on an arm portion (not shown) of the sewing machine frame 1 so as to be movable up and down and swingable in the cloth feeding direction.

When the sewing machine is running, the needle 5 is moved downward while carrying the upper thread T1, passes through the presser foot 6, the work cloth W on the work cloth support surface 3, and the throat plate 2 in order, and passes through the needle of the feed dog 4. Insertion hole 4a
, the feed dog 4 is moved upward, and in this state, the needle 5 and the feed dog 4 are integrally moved rearward, and feed is applied to the work cloth W. There is.

A pair of thread ring catchers 7 are disposed in the bed part la of the sewing machine frame 1 below both sides of the feed dog 4, and a pair of thread ring catchers 7 are provided in the bed part la corresponding to the thread ring catchers 7 according to the present invention. A thread cutting device 8 embodying the above is provided respectively. Note that in FIGS. 1(a) to 1(d), only one of the yarn loop catcher 7 and yarn cutting device 8 is illustrated, and the description of the other one is omitted.

Therefore, first of all, the thread ring catcher 7 will be described in detail. An outer hook 10 is fixed to the upper end of a rotating shaft 9 that is rotatably supported around a vertical axis in the bed portion a, and a part of the outer circumference of the rotating shaft 9 is fixed to the upper end of the rotating shaft 9. is provided with a thread ring catcher 10a for catching the upper thread T1 and a protrusion 10b for temporarily retaining the upper thread thread ring TL.

An inner hook 11 is housed in the outer hook 10 in a stationary state, and a bobbin 12 with a bobbin thread T2 wound thereon is housed therein so as to be relatively rotatable. Then, by rotating the outer hook 10 of the thread loop catcher 7 in the clockwise direction in FIG. 1(a), a lock stitch is formed on the work cloth W in cooperation with the vertical movement of the needle 5. It is now possible to do so.

Next, regarding the thread cutting device 8, a fixed blade 13 is attached to the lower surface of the needle plate 2 by a screw 14 so as to be located on one side of the vertical movement path of the needle 5. A movable blade 15 is disposed in the bed portion la adjacent to the lower portion of the fixed blade 13 so as to be movable back and forth in the front and rear directions, and a thread handling portion 15a is formed at the tip thereof. Its tip thread handling part 15a
Subsequently, a recess 15b is formed on the side edge of the tip of the movable blade 15 on the side facing the needle 5, and the recess 15b is formed for threading.
A cutting edge part 15'c is provided on the upper surface of the movable blade 15 so as to be located near the inner inner part of the movable blade 15'.

When the movable blade 15 is moved forward, the upper thread thread ring TI is moved at the tip thread handling section 15a as shown in FIG. 1(a).

When the bobbin thread T2 unwound from the bobbin 12 is unwound and the movable blade 15 is moved back, the thread hook is attached to the fabric side leg of the upper thread loop TL in the recess 15b as shown in FIG. 1(b). The portion Tw and the bobbin thread T2 are captured, and then, as shown in FIG. 1(C), both the threads T1
, T2 are cut at the same time.

A pressing member 16 made of an elastic plate is disposed in the bed portion a of the sewing machine frame 1 so as to be located adjacent to the lower part of the movable blade 15, and is opposed to the thread loop catcher 7 at the tip thereof. A recess 16a is formed in the side edge on the side where the cover is opened. and,
In a state where the movable blade 15 is further moved back after cutting the thread,
As shown in FIG. 1(d), the needle side limb Tn of the needle thread ring TL and the lower thread T2 after cutting are pressed toward the lower surface of the movable blade 15 by this pressing member 16, and the pressing member 16 It is designed to be held between the movable blade 15 and the movable blade 15.

A notch recess 17 is formed on the side edge opposite to the recess 15b, and this notch recess 17 and the protrusion 10b on the outer periphery of the outer shuttle 10 allow the thread to be caught when cutting the thread. A means 18 is provided for separating the needle side limb Tn of the needle thread ring TL captured in the recess 15b from the bobbin thread T2 on the bobbin 12 side. In this embodiment, as shown in FIG. 1(b), as the movable blade 15 moves back, the needle thread ring TL moves from the needle 5 side to the notch recess 17, the protrusion tob and The thread hooks are sequentially locked in the recesses 15b and passed through a thread path different from the lower thread T2 on the bobbin 12 side, and in this state, the upper thread thread ring TL
6, it is pressed and clamped toward the movable blade 15. Further, after both threads T1 and T2 are cut due to the backward movement of the movable blade 15 from the above state, as shown in FIG. 1(d), the needle side limb Tn of the needle thread ring TL after cutting is released from the pressed and clamped state in response to the recess 16a of the pressing member 16, and only the bobbin thread T2 on the bobbin 12 side is held in the pressed and clamped state between the pressing member 16 and the movable blade 15. There is.

Incidentally, in a conventional thread cutting device that does not include the means 18, thread portions such as the cutout recess 17 on the movable blade 15 are shown with the same reference numerals in FIGS. 8(a) to 8(d). As the movable blade 15 moves back, the thread hook is cut with the needle side limb Tn of the needle thread ring TL captured by the recess 15b and the bobbin thread T2 on the bobbin 12 side drawn together. , is pressed and held between the pressing member 16 and the movable blade 15. Therefore, in this conventional device, the needle side limb Tn of the needle thread ring TL is then moved between the pressing member 16 and the movable blade 1 by a wiper device or the like.
When the bobbin thread T2 is pulled out from between the pressing member 16 and the movable blade 15, the first stitch cannot be reliably formed when the next sewing starts. There is.

However, in the thread cutting device embodying the present invention, as described above, the cutout recess 17 on the movable blade 15 and the outer hook 1
Since a means 18 is provided for the yarn that is tied to the protrusion 10b on the 0, as shown in FIGS. The needle side limb Tn of the captured upper thread thread ring TL is cut in a state separated from the lower thread T2 on the bobbin 12 side based on the locking by the notch recess 17 and the protrusion 10b, and the pressing member 16 and the movable blade 15. Therefore, when the needle-side limb Tn of the needle thread ring TL is subsequently pulled out by a wiper device or the like, there is no risk that the bobbin thread T2 will be pulled out from between the pressing member 16 and the movable blade 15, and the next sewing will be carried out. The first stitch at the start can be reliably formed.

It should be noted that the present invention is not limited to the configuration of the above-mentioned embodiments, and may be embodied, for example, in a sewing machine equipped with a thread loop catcher having an outer hook rotatable around a horizontal axis, It is also possible to change the structure of each part arbitrarily and embody it without departing from the spirit of the invention, such as by providing the cutout recess 17 on a member different from the movable blade 15.

Effects of the Invention As detailed above, in this invention, when the movable blade moves to cut both the upper and lower threads, the thread hook of the movable blade is connected to the needle side limb of the needle thread loop captured by the recess and the bobbin side. In order to separate the bobbin thread from the bobbin thread, a means was provided to separate the needle thread and the bobbin thread from the needle side limb of the needle thread loop and the bobbin thread. Both threads are cut in a state where they are separated, and these threads are pressed and clamped in a separated state between a pressing member and a movable blade, and then the needle side limb of the needle thread loop is pulled out. However, the bobbin thread is not pulled out at the same time, and the bobbin thread remains pressed between the pressing member and the movable blade. This has the excellent effect of being able to form stitches reliably.

[Brief explanation of drawings]

1(a) to (d) are partial plan views showing the thread cutting device of a sewing machine embodying the present invention in the order of operation; FIG. 2 is a partial sectional view of the sewing machine showing an enlarged portion of the thread cutting device; Third
Figures (a) to (d) are partial plan views showing a conventional thread cutting device in the order of its operation. 1a... Bed part, 2... Throat plate, 5... Needle, 7...
... Thread ring catcher, thread cutting device, 10... outer hook,
10a... Thread ring catcher, 10b... Protrusion, 12...
・Bobbin, 13...Fixed blade, 15...Movable blade, 15
a... Tip thread handling part, +, 5 b... Thread hook is concave part, 15c... Cutting blade part, 16... Pressing member, 17...
・Notch recess, 18...excess is means.

Claims (1)

[Claims] 1. A throat plate (2) attached to the bed portion (1a), and a needle (2) that passes through the throat plate (2) and moves up and down while carrying the upper thread (T_1). 5), and a thread ring catching beak (10a) which is rotatably supported around one axis below the throat plate (2) and is provided on a part of its outer periphery.
) and a bobbin (12) housed in the outer hook (10) with the bobbin thread (T_2) wound thereon.
and a thread loop catcher (7) for forming a stitch in cooperation with the needle (5), the sewing machine comprising: Throat plate (2
) and a fixed blade (13) provided below the fixed blade (
13), and is disposed movably adjacent to the tip thread handling section (15a), and a thread hooking recess (15b) formed following the tip thread handling section (15a) and its thread hooking recess (15b). and a cutting blade (15c) located near the inner inner part of the bobbin (12), which cuts the lower thread (T_2) unreeled from the cloth side limb (Tw) of the upper thread loop (TL) and the bobbin (12). As it moves, after being caught in the thread hooking recess (15b),
A movable blade (15) for cutting at the same time by cooperation of the cutting blade (15c) and the fixed blade (13), and a needle thread ring located adjacent to the movable blade (15) after cutting. a pressing member (16) for pressing and holding the needle side limb (Tn) of the (TL) and the bobbin thread (T_2) toward the movable blade (15); Both threads (T_1, T
When cutting _2), the needle side limb (Tn) of the needle thread loop (TL) captured by the thread hooking recess (15b);
A thread separating means (18) that acts on at least one of the upper thread (T_1) and the lower thread (T_2) is provided so that the lower thread (T_2) on the bobbin (12) side is separated. Features: Sewing machine thread cutting device. 2. The thread separating means (18) is connected to a notch recess (17) provided on the side edge of the movable blade (15) opposite to the thread hooking recess (15b), and the thread ring catcher (7). Outer pot (10
) a protrusion (10b) provided on the outer periphery;
Before thread cutting, the needle thread loop (TL) is connected to the needle (5).
) side, the bobbin (12) is sequentially locked in the notch recess (17), the protrusion (10b), and the threading recess (15b).
The needle thread ring (TL) is configured to be pressed and clamped by the pressing member (16) toward the movable blade (15) while being passed through a thread path different from that of the lower thread (T_2) on the side. A thread cutting device for a sewing machine according to claim 1.