JP2009000440A - Sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To favorably prevent the twining of a looper thread. <P>SOLUTION: This sewing machine includes a lower shaft 2, a looper operatively connected with the rotation of the lower shaft and swinging, two threading parts 11 and 12, two thread control cams 13 and 14 provided in the lower shaft 2 to bring the looper thread L laid across the two threading parts 11 and 12 into slide contact with their outer circumferential parts, and a thread guide member 15 provided between the two thread control cams 13 and 14, reciprocating the looper thread L coming into slide contact with the thread control cams 13 and 14 along a fixed route and having a long hole part 15a, wherein a notch 15b is formed in an inner edge part 15d on the lower shaft side of the long hole part 15a of the thread guide member 15. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sewing machine that performs sewing using a looper thread guided by a looper and includes a thread control device that controls the tension of the looper thread.

  A sewing machine that performs edge stitching and double chain stitching has a looper below the needle plate, and the looper thread that swings below the needle plate captures the loop of the upper thread guided by the sewing needle, and the looper thread that the looper guides Sewing is performed by repeating the operation of the sewing needle capturing the loop of L1. At this time, as a yarn control device that keeps the tension of the looper yarn L1 constant, two looper portions 111 and 112 as a route of the looper yarn L1 and a looper yarn that is provided on the lower shaft and passes between the threading portions. Two thread control cams 113 and 114 whose outer peripheral portion is in sliding contact with L1 and a long hole for passing a looper thread L1 provided between the two thread control cams and in sliding contact with the two thread control cams A sewing machine including a yarn control device 110 including a yarn guide member 115 provided with a portion 115a is widely used (see FIG. 13A).

FIG. 13 is an explanatory diagram showing the positional relationship between the conventional yarn control device 110 and the looper yarn L1. FIG. 13 (a) is an explanatory view showing the position of the looper thread L1 during normal sewing. FIG. 13B is an explanatory view showing the position of the looper yarn L1 in a state where the looper yarn L1 is wound around the shaft portion 102a of the gap formed between the two yarn control cams 113 and 114. FIG. .
As shown in FIG. 13 (a), the thread control device 110 connects the hole 111a of the threading part 111, the hole 112a of the threading part 112, and the elongated hole 115a of the thread guide member 115 to the looper thread L1. Is provided to pass through. Further, the looper (not shown) is provided on the side where the threading portion 111 is provided (left side in FIG. 13A), and the thread winding (not shown) as a yarn supply source of the looper yarn L1 is provided by the threading portion 112. It is provided on the provided side (the right side in FIG. 13A). Further, in accordance with the change in tension of the looper yarn L1 accompanying the swing of the looper, the yarn control cams 113 and 114 are in sliding contact with the portion of the looper yarn L1 located between the threading portions 111 and 112, and the looper yarn L1 is brought into contact with the looper yarn L1. The tension of the looper yarn L1 is maintained by applying the tension.

  By the way, during the sewing operation of the sewing machine using the thread control device 110, the looper thread L1 may cause thread breakage for some reason. The thread breakage often occurs on the looper side with respect to the threading part 111 in FIG. In this case, the looper yarn supply source end of the looper yarn L1 in which the yarn breakage has occurred winds around one of the lower shafts 102, particularly the shaft portion 102a between the two yarn control cams 113 and 114, and the lower shaft Along with the rotation of 102, a large amount of looper yarn L1 may be wound around the shaft portion 102a. The removal of the looper yarn L1 wound around the shaft portion 102a is very complicated, and it takes a lot of time to remove the looper yarn L1, which places a great burden on the operator and increases the efficiency of the sewing work. Reduce significantly. Further, when an operation of cutting the looper yarn L1 wound around the shaft portion 102a using a cutter or the like is performed at the time of the removal, the cutter is accidentally hit against the yarn control cams 113 and 114 at the time of the operation. Sometimes. In this case, in the sewing work performed after the scratch occurs, the looper thread L1 may be easily cut and wound by the looper thread L1 being caught on the scratch.

For this reason, a yarn cutting blade that operates so as to repeat contact and non-contact with the looper yarn L1 on the path of the looper yarn L1 closer to the yarn winding side than the yarn control cam 114 is provided, and the looper yarn L1 is wound. When this occurs, a configuration is known in which the blade contacts the looper yarn L1 to cut the looper yarn L1 (for example, Patent Document 1).
Japanese Utility Model Publication No. 3-55077

  However, in the conventional sewing machine according to Patent Document 1, when the looper yarn L1 is pulled out while the blade arranged substantially parallel to the loop of the looper yarn L1 is in contact with the looper yarn L1, the blade acts. It is configured. For this reason, depending on the thickness and material of the looper thread L1, the looper thread L1 may slide with respect to the blade, and the blade may not function sufficiently, so that thread trimming may not be performed. Therefore, when the cutting is not performed, a large amount of looper yarn L1 is wound, and there is a problem that the removal of the wound looper yarn L1 becomes very complicated. Further, since a blade for cutting the yarn is separately provided on the loop of the looper yarn L1, there is a problem that the design of the sewing machine is limited to provide an installation space for the blade. Further, the conventional sewing machine according to Patent Document 1 has a mechanism that operates so that the looper thread L1 is cut only when the looper thread L1 is wound by repeating contact and non-contact with the looper thread L1. Due to the complexity, the design of the sewing machine is complicated, and in addition, there is a problem that the configuration for thread trimming is expensive.

  In view of the above-described problems, an object of the present invention is to more appropriately prevent looping of a looper yarn.

  According to the first aspect of the present invention, there is provided a lower shaft that is rotated by the rotation of a sewing machine motor, a looper that swings in conjunction with the rotation of the lower shaft, two threading portions, and the two threading portions. Between the two thread control cams and the two thread control cams, which are arranged and the outer periphery cam provided on the lower shaft so that the looper thread crossing the two threading parts is in sliding contact with the outer periphery. A thread guide member provided with a long hole portion through which the looper thread that is slidably contacted with each of the thread control cams is inserted and reciprocating the looper thread along a predetermined direction, and the looper thread In the sewing machine that applies tension by changing the diameters of the two yarn control cams, the yarn guide member is an inner edge on the lower shaft side of two inner edge portions along the longitudinal direction of the elongated hole portion. Thread cutting means for cutting the looper thread in the middle of the section Characterized in that it obtain.

  According to a second aspect of the present invention, in the sewing machine according to the first aspect, from the outer periphery of the yarn control cam to the lower shaft on the looper yarn supply source side relative to the yarn control cam on the looper yarn supply source side. It is characterized by comprising a yarn catching member fixed to the sewing machine frame at a position between them and catching the end of the looper yarn.

  According to a third aspect of the present invention, in the sewing machine according to the first aspect, the first cylindrical portion that inserts the lower shaft into the side surface of the yarn control cam on the looper yarn supply source side on the looper yarn supply source side is integrally formed. And a cutting member that cuts the looper yarn with a blade portion disposed in proximity to the outer peripheral surface of the first cylindrical portion.

  According to a fourth aspect of the present invention, in the sewing machine according to the third aspect, a second cylindrical portion that is fixed to the sewing machine frame and passes through the lower shaft is provided, and one end of the second cylindrical portion is connected to the first cylindrical portion. It is characterized by being inserted inside the end of the cylindrical portion on the looper yarn supply source side.

  According to a fifth aspect of the present invention, in the sewing machine according to any one of the first to fourth aspects, the thread trimming means hooks the looper thread by a change in a diameter accompanying rotation of the thread control cam, and further the diameter It is a thread hook part which cuts the looper thread with the change of.

  According to a sixth aspect of the present invention, in the sewing machine according to any one of the first to fifth aspects, the thread trimming means is a concave portion provided in the inner edge portion.

  According to a seventh aspect of the invention, in the sewing machine according to any one of the first to fifth aspects, the thread trimming means is a convex portion provided on the inner edge portion.

According to the first aspect of the present invention, when the cut looper yarn is wound around the shaft portion of the gap formed between the two yarn control cams, the yarn trimming means cuts the looper yarn. At this time, the yarn trimming means is provided on the middle side of the inner edge portion which is the lower shaft side, out of the two inner edge portions along the longitudinal direction of the elongated hole portion provided in the yarn guide member. That is, the thread trimming means is provided so as to cut the looper yarn only when the cut looper yarn is wound around the lower shaft and one end of the looper yarn is pulled toward the lower shaft. As a result, the thread trimming means will not unnecessarily cut the looper thread during normal sewing work, and the looper thread cut for some reason will be generated in the shaft portion of the gap generated between the two thread control cams. Cut the looper thread only when it is wound. Therefore, the reliability of the sewing machine is further improved.
Further, the thread trimming means cuts the looper thread before a large amount of looper thread is wound. At this time, the end on the supply source side of the looper yarn cut by the thread cutting means is swept by the yarn control cam on the looper yarn supply source side of the two yarn control cams, and is not wound around the shaft portion again. Absent. As a result, the amount of looper yarn wound around the shaft portion becomes extremely small, and removal of the wound looper yarn becomes easy. Therefore, a conventional problem that a large amount of looper yarn is wound and the removal of the looper yarn becomes very complicated can be solved, and the reliability and comfort of the sewing machine are greatly improved.
Furthermore, since the thread trimming means is provided at the inner edge of the elongated hole provided in the thread guide member, there is no need to secure a separate member and blade installation space for fixing the blade as in the prior art. The degree of freedom in designing the sewing machine is further improved.
Furthermore, since the thread trimming means does not require a mechanism for repeating contact and non-contact with the looper thread as in the prior art, the configuration for cutting the looper thread becomes extremely simple, and the sewing machine In addition to being easier to design, it is possible to provide a sewing machine that can cut the looper yarn when the looper yarn is wound at an extremely low cost.
The thread trimming means is not limited to a blade shape. For example, as in the fifth aspect of the invention, a structure may be employed in which the movement of the looper yarn that moves along the inner edge portion on the lower shaft side is captured and blocked in the middle by the yarn control cam on the looper yarn supply source side. . Thus, the looper yarn can be torn by pulling the looper yarn by the lower shaft and the yarn control cam on the looper yarn supply source side, and as a result, the looper yarn functions.

  According to the second aspect of the invention, the yarn catching member is closer to the looper yarn supply source side than the outer circumference of the yarn control cam on the looper yarn supply source side, and is located between the outer circumference and the lower shaft. Is provided. That is, the end of the looper yarn that has fallen to the side surface of the looper yarn supply source side of the yarn control cam near the looper yarn supply source can be captured. As a result, it is generated between the side surface on the looper yarn supply source side of the yarn control cam on the yarn supply source side of the looper yarn and the bearing provided on the side surface side of the bearing that rotatably supports the lower shaft. It is possible to prevent the end portion of the cut looper yarn from being wound around the gap. Therefore, a problem that a large amount of looper yarn is wound around the gap and the removal of the looper yarn becomes very complicated can be solved, and the reliability and comfort of the sewing machine are greatly improved.

  According to the invention of claim 3, the first cylindrical portion is provided integrally with the yarn control cam on the side surface on the looper yarn supply source side of the yarn control cam on the looper yarn supply source side, and passes through the lower shaft. . That is, the first cylindrical portion is provided so as to cover the outer peripheral portion of the lower shaft 2 on the side surface side on the looper yarn supply source side of the yarn control cam. Accordingly, when the end portion of the cut looper yarn is positioned on the side surface of the yarn control cam on the looper yarn supply source side, the looper yarn is wound around the outer peripheral portion of the first cylindrical portion. Therefore, it is possible to prevent the looper yarn from being wound around the lower shaft. Further, at this time, the blade portion disposed in the vicinity of the outer peripheral portion of the cylindrical portion of the cutting member cuts the looper yarn wound around the first circumferential portion, so that a large amount of the looper yarn is formed on the outer peripheral portion of the first cylindrical portion. It is cut without winding around. Therefore, when the looper yarn breaks, the looper yarn is wound around the lower shaft in a large amount, and the problem that the removal of the looper yarn becomes very complicated can be solved, greatly improving the reliability and comfort of the sewing machine. To improve.

  According to the fourth aspect of the present invention, the end portion of the first cylindrical portion on the looper yarn supply source side is arranged so that the second cylindrical portion fixed to the sewing machine frame is inserted therein. For example, the end of the first cylindrical portion on the looper yarn supply source side has a lower shaft bearing inserted therein. That is, the outer peripheral surface of the lower shaft is completely covered with the first cylindrical portion and the second cylindrical portion between the side surface on the looper yarn supply source side of the yarn control cam on the looper yarn supply source side and the bearing. Become. Accordingly, it is possible to prevent the end portion of the cut looper yarn from being wound around the outer peripheral surface of the lower shaft between the side surface on the looper yarn supply source side of the yarn control cam on the looper yarn supply source side and the bearing. . Therefore, a problem that a large amount of looper yarn is wound around the gap and the removal of the looper yarn becomes very complicated can be solved, and the reliability and comfort of the sewing machine are greatly improved.

  According to the invention of claim 5, the thread trimming means is a thread hooking section for hooking the looper thread. In other words, when the cut looper yarn is wound around the lower shaft and one end of the looper yarn is pulled to the lower shaft side, the looper yarn is the inner edge of the lower shaft side of the elongated hole portion of the yarn guide member. It catches on the thread hook part provided in. At this time, the looper yarn uses the yarn hooking portion as a fulcrum, and the looper yarn wound around the shaft portion of the gap generated between the two yarn control cams is pulled by the rotation of the lower shaft, and the looper yarn supply The tensile force accompanying the change of the looper yarn path is received by sliding with the yarn control cam on the source side. That is, the looper yarn is pulled in two different directions with the yarn hooking portion as a fulcrum. As a result, the looper yarn is torn at the yarn hooking portion and cut. Therefore, since it is not necessary to process the thread trimming means into a blade shape, the thread trimming means can be provided at a lower cost.

According to the sixth aspect of the present invention, since the thread trimming means is a recess provided in the inner edge of the elongated hole provided in the thread guide member, the looper thread wound without cutting a separate blade or the like can be cut. It can be carried out.
Further, the thread trimming means can be provided without making a significant design change to the conventional thread control device. Therefore, the thread trimming means can be provided at a lower cost.

According to the seventh aspect of the present invention, since the thread trimming means is a convex portion provided at the inner edge of the elongated hole portion provided in the yarn guide member, the looper yarn wound without any additional blade or the like is cut. It can be performed.
Further, the thread trimming means can be provided without making a significant design change to the conventional thread control device. Therefore, the thread trimming means can be provided at a lower cost.

(Overall configuration of the embodiment of the sewing machine according to the present invention)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The sewing machine according to the present invention is a sewing machine that performs sewing using a looper thread L guided by a looper provided below a needle plate, and includes a thread control device 10 that controls the tension of the looper thread L. .

FIG. 1 is a perspective view showing a configuration of a yarn control device 10 provided in a sewing machine according to the present invention.
The sewing machine includes a lower shaft 2 disposed inside the bed portion of the sewing machine frame, and a sickle-like protruding portion that swings in conjunction with the rotation of the lower shaft 2 below a needle plate provided on the upper surface of the bed portion. A looper (not shown) having a loop, a spool (not shown) as a supply source of the looper yarn L guided by the looper, and a yarn control provided so as to be positioned on the looper loop L between the looper and the spool Device 10.

The sewing machine has an upper shaft arranged along the extending direction of the arm portion of the sewing machine frame, a sewing machine motor that rotates the upper shaft, and a sewing machine that is provided on the lower surface portion of the arm portion to hold the sewing needle. A needle bar that moves up and down, a vertical movement mechanism that connects the needle bar and the upper shaft, converts the rotational movement of the upper shaft into vertical movement and transmits it to the needle bar, and lowers the rotation of the upper shaft. A power transmission mechanism for transmitting to the shaft 2.
When the sewing machine motor rotates, the upper shaft rotates. The rotation of the upper shaft moves the needle bar up and down via a vertical movement mechanism. At this time, the upper thread that conducts through the hole at the tip of the sewing needle is guided to reciprocate up and down the needle plate as the needle bar moves up and down, and when the sewing needle descends and then rises, Form a loop below. Further, the rotation of the upper shaft is transmitted to the lower shaft 2 through the power transmission mechanism, and the lower shaft 2 is rotated. The rotation of the lower shaft 2 swings the looper. The looper has a hole through which the looper yarn L is passed at the tip of the sickle-shaped protrusion, and the looper yarn L is guided as the looper swings. At this time, when the sewing needle moves forward so that the protruding portion of the looper enters inside the loop of the upper thread formed by the sewing needle when the sewing needle moves up after being lowered, and swings so as to move backward from the advance position. The lowered sewing needle enters the loop of the looper thread L formed by the looper thread L. That is, the stitches are formed so that the upper thread and the looper thread L pass through the loops formed by the upper thread and the looper thread L alternately. In this way, sewing is performed as is well known.
Further, the rotation of the lower shaft 2 operates the yarn control device 10. The operation of the yarn control device 10 will be described later.

(Thread control device)
Next, the yarn control device 10 will be described in detail.
As shown in FIG. 1, the yarn control device 10 is fixed to the lower shaft and the threading portions 11 and 12 provided above the lower shaft 2 and provided with holes 11a and 12a serving as a route for the looper yarn L. Yarn control cams 13 and 14 which are supported and shielded between the threading portions 11 and 12 and whose outer periphery is in sliding contact with the looper yarn L passing through the holes 11a and 12a, and the yarn control cam 13 , 14 and a thread guide member 15 provided with an elongated hole portion 15a serving as a route for the looper yarn L, and a thread guide portion 11 and 12 and a thread guide member 15 for supporting the thread guide members 15 so as to be pivotable up and down. Moving part 16. Further, the sewing machine is fixedly held on the sewing machine frame and rotatably supports the lower shaft 2, and the looper thread L route provided on the sewing machine frame and derived from a bobbin as a supply source of the looper thread L. And a yarn catching member 20 (see FIG. 5) provided on the bearing 4 and covering the gap 2b formed between the yarn control cam 14 and the bearing 4 from the upper surface.

The threading portions 11 and 12 and the yarn guide member 15 are supported by the rotating portion 16. One end of the rotating part 16 is pivotally supported by the sewing machine frame, and the other end part is provided above the lower shaft 2 so as to be vertically rotatable. That is, the threading portions 11 and 12 and the thread guide member 15 are provided at the other end portion of the rotating portion 16, and the threading portions 11 and 12 and the thread guiding portion 15 are rotated by the vertical rotation of the other end portion of the rotating portion 16. The guide member 15 can be switched between a position at the time of use (position in FIG. 1) and a position at the time of non-use such as maintenance (see FIG. 7).
Further, as described above, the threading portions 11 and 12 are provided with the holes 11a and 12a serving as the looper yarn L path. Further, the thread guide member 15 is provided with a long hole portion 15a that becomes a path of the looper thread L. The looper yarn L led out from the yarn path portion 5 first passes through the hole portion 12a, then passes through the long hole portion 15a, and finally passes through the hole portion 11a and is led out to the looper. At this time, the looper yarn L is in sliding contact with the outer peripheral portion of the yarn control cam 14 between the hole portion 12a and the elongated hole portion 15a, and between the outer peripheral portion of the yarn control cam 13 between the elongated hole portion 15a and the hole portion 11a. Make sliding contact.

FIG. 2 is an explanatory diagram showing the positional relationship between the yarn guide member 15 and the lower shaft 2.
As shown in FIG. 2, the longitudinal direction of the long hole portion 15 a of the yarn guide member 15 when the rotating portion 16 is at the position in use is relative to the radial direction of the circle centering on the lower shaft 2. The lower shaft side end portion 15c of the guide member 15 is inclined to the upstream side in the rotational direction of the yarn control cams 13 and 14. At this time, the thread control cams 13 and 14 that rotate in accordance with the rotation of the lower shaft 2 have the inner edge portion 15e on the needle plate side of the elongated hole portion 15a as the upstream side, and the inner edge portion on the lower shaft side of the elongated hole portion 15a. Further, the rotation direction of the yarn control cams 13 and 14 rotating with respect to the yarn guide member 15 is set at a predetermined position of the inner edge portion on the lower shaft side of the long hole portion 15a of the yarn guide member 15. A notch 15b, which is a recess formed in a direction from the upstream portion toward the downstream portion, is provided. When the looper yarn L is wound around the shaft portion 2a between the two yarn control cams 13 and 14, the looper yarn L is caught and cut off. The notch 15b will be described later.

The thread control cams 13 and 14 have the same shape, and a part of the outer periphery has a large diameter part that is further away from the lower shaft 2 than the other part (small diameter part).
FIG. 3 is a perspective view showing the yarn control device 10 when the large diameter portions of the yarn control cams 13 and 14 are in contact with the looper yarn L. FIG.
The thread control cams 13 and 14 are cams having the lower shaft 2 as a rotation axis. The thread control cams 13 and 14 are provided so that the outer peripheral portions thereof are in sliding contact with the looper thread L as described above. Further, the yarn control cams 13 and 14 have a shape in which the diameter with respect to the rotation shaft changes. That is, when the yarn control cams 13 and 14 are rotated by the rotation of the lower shaft 2, the timing at which the small diameter portions of the yarn control cams 13 and 14 are in sliding contact with the looper yarn L (the state in FIG. 1), and the yarn control cams 13 and 14 The path of the looper yarn L changes along the elongated hole portion 15a of the yarn guide member 15 between the timing when the large diameter portion 14 is in sliding contact with the looper yarn L (state of FIG. 3).

At this time, the change timing of the diameter of the yarn control cams 13 and 14 with respect to the looper yarn L corresponds to the swing timing of the looper.
For example, when the looper moves backward with respect to the sewing needle, the distance between the looper and the thread control device 10 is shortened. At this time, the yarn control cams 13 and 14 operate so that the large diameter portion is in sliding contact with the looper yarn L. Accordingly, the looper yarn L from the hole portion 11a of the threading portion 11 to the looper is pulled by the yarn control cam 13, and tension is applied to the looper yarn L between the looper and the hole portion 11a. The thread L does not loosen. At this time, the yarn control cam 14 pulls the looper yarn L on the yarn path portion 5 side. As a result, the looper yarn L is pulled out from the spool as a supply source of the looper yarn L.
On the other hand, when the looper moves forward relative to the sewing needle, the distance between the looper and the thread control device 10 increases. At this time, the yarn control cams 13 and 14 operate so that the small diameter portion is in sliding contact with the looper yarn L. As a result, the looper yarn L pulled when the large-diameter portion of the yarn control cams 13 and 14 is in sliding contact with the looper yarn L is pulled by the looper instead of the yarn control cams 13 and 14, and tension is applied. The In this way, the tension of the looper yarn L corresponding to the swinging of the looper is maintained.

FIG. 4 is an explanatory view showing a route of the looper yarn L at the inner edge portion of the elongated hole portion 15a of the yarn guide member 15. FIG. 4A is an explanatory diagram showing a route of the looper yarn L before passing over the notch 15b. FIG. 4B is an explanatory diagram showing a route of the looper yarn L when passing over the notch 15b. FIG. 4C is an explanatory view showing the route of the looper yarn L after passing over the notch 15b.
During normal sewing operation, that is, when the thread breakage has not occurred, the looper thread L slides with the thread control cams 13 and 14 that rotate in accordance with the rotation of the lower shaft 2, so that the elongated hole portion of the thread guide member 15 is formed. The path for 15a is displaced. Specifically, the loop of the looper yarn L shown in FIG. 4A is displaced from the route of the looper yarn L shown in FIG. 4B to the route of the looper yarn L shown in FIG. . At this time, as shown in FIGS. 4A to 4C, the looper yarn L is displaced without being in contact with the inner edge portion on the lower shaft side of the elongated hole portion 15 a of the yarn guide member 15. That is, the looper yarn L when no yarn breakage occurs does not get caught in the notch 15b.
The looper yarn L passing through the long hole portion 15a is displaced along the path reciprocating along the longitudinal direction of the long hole portion 15a inside the long hole portion 15a by sliding with the yarn control cams 13 and 14. That is, the looper yarn L is displaced inside the elongated hole portion 15a so as to reciprocate in the left-right direction in FIGS.

(Looper yarn breakage and winding)
Next, the displacement of the looper yarn L until the looper yarn L is wound around the shaft portion 2a between the two yarn control cams 13 and 14 when the yarn breakage of the looper yarn L occurs will be described in detail.
FIG. 5 is an explanatory view showing the displacement of the looper yarn L when the yarn breakage of the looper yarn L occurs. FIG. 5A is an explanatory view showing the moment when the looper yarn L is cut on the looper side with respect to the threading portion 11 on the side close to the looper. FIG. 5B is an explanatory diagram showing the looper yarn L swept by the yarn control cam 13. FIG. 5C is an explanatory view showing a state in which the looper yarn L is wound around the shaft portion 2 a between the two yarn control cams 13 and 14.
As shown in FIG. 5A, in general, the thread breakage of the looper thread L often occurs closer to the looper than the thread control cam 13 during the sewing operation by the sewing machine. At this time, the end portion L1 of the looper yarn L on the looper yarn supply source side is swept by sliding with the outer periphery of the yarn control cam 13 as the lower shaft 2 rotates. At this time, the looper yarn L may fall between the yarn control cam 13 and the yarn guide member 15 as shown in FIG. In this case, as shown in FIG. 5C, the end portion L1 of the looper yarn L that has fallen between the yarn control cam 13 and the yarn guide member 15 is the shaft portion between the two yarn control cams 13 and 14. Wrap around 2a.

(Thread trimming means)
Next, a mechanism for cutting the looper yarn L wound around the shaft portion 2a by the notch 15b will be described in detail.
FIG. 6 is an explanatory diagram showing a route of the looper yarn L with respect to the elongated hole portion 15a of the yarn guide member 15 when the looper yarn L is wound around the shaft portion 2a between the two yarn control cams 13 and 14. FIG. 6A is an explanatory diagram showing a route of the looper yarn L before passing through the arrangement position of the notch 15b. FIG. 6B is an explanatory view showing a route of the looper yarn L caught in the notch 15b. FIG. 6C is an explanatory diagram showing a route of the looper yarn L that is pulled in two directions with the notch 15b as a fulcrum.
When the lower shaft 2 continues to rotate in a state where the looper yarn L is wound around the shaft portion 2a, the looper yarn L passes through the paths shown in FIGS. 6A to 6C with respect to the elongated hole portion 15a of the yarn guide member 15. Guided by the yarn control cam 14. That is, the looper yarn L led out from the threading portion 12 descends around the axis of the lower shaft 2 when the looper yarn supply end end L1 of the broken looper yarn L is wound around the shaft portion 2a. I take the. At this time, when the yarn control cam 14 and the looper yarn L are slidably contacted with the end portion L1 wound around the shaft portion 2a, the route of the looper yarn L is the inner edge of the elongated hole portion 15a of the yarn guide member 15 on the lower shaft side. Displaces so as to be in sliding contact with the part. Therefore, as shown in FIG. 6B, the looper yarn L that is displaced so as to be in sliding contact with the inner edge portion on the lower shaft side of the elongated hole portion 15a of the yarn guide member is caught by the notch 15b.

When the lower shaft 2 continues to rotate after the looper yarn L is caught in the notch 15b, the yarn control cam 14 further pulls the looper yarn L as shown in FIG. That is, the looper yarn L on the path from the notch 15b to the outer periphery of the yarn control cam 14 is pulled in the direction of the arrow A. On the other hand, as the lower shaft 2 rotates, the looper yarn L wound around the shaft portion 2a is urged to be further wound, so that the looper yarn L on the path from the notch 15b to the shaft portion 2a moves in the direction of arrow B. And pulled. Therefore, the looper yarn L is pulled in the direction of the arrow A and the direction of the arrow B with the notch 15b as a fulcrum, so that a very strong engagement force acts on the position of the notch 15b. Due to the tension, the looper yarn L is torn off with the notch 15b as a fulcrum and cut. Therefore, the notch 15b functions as a “thread hook” and a “thread cutting means”.
As shown in FIG. 2, the notch 15b is on the side of the notch 15b that locks the looper thread L so that the looper thread L caught on the notch 15b does not slide out of the notch 15b. It is desirable that the angle of the projecting portion 15f formed by the side portion and the inner edge portion 15d on the lower shaft side of the long hole portion 15a is greater than 0 degree and equal to or less than a right angle.

  Of the looper yarn L cut by the notch 15b, the end portion of the looper yarn L that is wound around the shaft portion 2a does not support the end portion, so that no tensile force is generated. Therefore, even if the lower shaft 2 continues to rotate, the looper yarn L wound around the shaft portion 2a is not tightened. Further, the length of the looper yarn L wound around the shaft portion 2a is the end portion of the looper yarn L cut by the notch 15b from the end portion L1 on the looper yarn supply source side when the yarn breakage of the looper yarn L occurs. It becomes only the length. Accordingly, even if the lower shaft 2 is rotated to some extent after the thread breakage of the looper thread L occurs during the sewing operation of the sewing machine, the amount of the looper thread L wound around the shaft portion 2a is small and the shaft portion The looper yarn L wound around 2a can be easily removed.

FIG. 7 is a perspective view showing the yarn control device 10 in which the rotation unit 16 is rotated upward.
When removing the looper yarn L wound around the shaft portion 2a, after the operation of the sewing machine is stopped, a lid portion (not shown) provided on the upper surface of the bed portion located above the yarn control device 10 is provided. As shown in FIG. 7, the rotating unit 16 is rotated upward to facilitate manual operation of each unit to the yarn control device 10. Thereafter, the looper yarn L wound around the shaft portion 2a by tweezers or the like is removed.
Of the looper yarn L cut by the notch 15b, the end portion L2 (see FIG. 8) on the looper yarn supply source side will be described later.

(Thread capture member)
Next, the yarn catching member 20 will be described in detail.
As shown in FIG. 5, the yarn catching member 20 is provided so as to cover the upper half of the gap 2 b formed between the yarn control cam 14 and the bearing 4 on the outer peripheral surface of the bearing 4. Further, the surface of the yarn catching member 20 is provided with a band-like raised along the arc of the outer periphery of the bearing 4, and when the end of the yarn falls on the surface, the end of the yarn is caused by frictional force. To capture. Further, the yarn catching member 20 is in contact with the side end of the yarn catching member 20 on the side of the yarn control cam 14 and the side of the yarn control cam 14 so that no gap is formed between the side of the yarn control cam 14. Has been appointed.

FIG. 8 is an explanatory diagram showing the path of the end portion L2 on the looper yarn supply source side of the looper yarn L cut by the notch 15b. In addition, Fig.8 (a) is explanatory drawing which shows the moment when the looper thread | yarn L was cut | disconnected by the notch 15b. FIG. 8B is an explanatory view showing the looper yarn L swept by the yarn control cam 14. FIG. 8C is an explanatory diagram showing a state in which the end portion L2 of the looper yarn L is captured by the yarn capturing member 20.
As shown in FIG. 8A, the end portion L2 on the looper yarn supply source side of the looper yarn L cut by the notch 15b is swept by the yarn control cam 14. At this time, as shown in FIG. 8B, the looper yarn L may fall into the gap between the yarn control cam 14 and the rotating portion 16. In this case, as shown in FIG. 8C, the end portion L <b> 2 that has fallen into the gap between the yarn control cam 14 and the rotating portion 16 falls on the upper surface portion of the yarn catching member 20. At this time, the end portion on the supply side of the looper yarn L is caught by the raised portions provided on the upper surface portion of the yarn catching member 20, and thereafter no longer moves. That is, the end portion on the supply side of the looper yarn L cut by the notch 15b is caught by the yarn catching member 20, so that it enters the gap 2b formed between the yarn control cam 14 and the bearing 4. No wrapping occurs. Therefore, the end portion L2 of the looper yarn L cut by the notch 15b is not wound again, and the looper yarn L in which the yarn breakage has occurred can be more easily processed.

Note that the end L1 on the looper yarn supply source side when the looper yarn L is broken is swept by the yarn control cam 14 without being wound around the shaft portion 2a, so that the yarn control cam 14 and the rotating portion 16 May fall into the gap between them. In this case, the end L1 is caught by the yarn catching member 20 and will not move thereafter. Therefore, the looper yarn L is not wound.
Further, the processing of the end portions L1 and L2 of the looper yarn L captured by the yarn capturing member 20 is performed in substantially the same manner as the processing of the looper yarn L wound around the shaft portion 2a. That is, after the operation of the sewing machine is stopped, a lid (not shown) provided on the upper surface of the bed located above the yarn control device 10 is opened, and the rotating unit 16 is moved upward as shown in FIG. It is made to rotate and the manual operation to each part to the thread control device 10 is facilitated. Then, the end portions L1 and L2 of the looper yarn L captured by the yarn capturing member 20 by tweezers or the like are removed, and the looper yarn L passes through the hole portion 12a, the long hole portion 15a, and the hole portion 11a again to return to the looper. The looper yarn L is guided by the operator so as to be led out.

(Effects of the sewing machine according to the above embodiment)
According to the above-described embodiment, when the cut looper yarn L is wound around the shaft portion 2a between the two yarn control cams 13 and 14, the notch 15b hooks the looper yarn L and cuts it. At this time, the notch 15b is provided on the middle side of the inner edge portion on the lower shaft side, out of the two inner edge portions along the longitudinal direction of the elongated hole portion 15a provided in the yarn guide member 15. That is, the notch 15b is provided so as to cut the looper yarn L only when one end of the looper yarn L is pulled to the lower shaft side by winding the cut looper yarn L around the lower shaft. . As a result, the notch 15b does not unnecessarily cut the looper yarn L during normal sewing work, and the looper yarn L cut for some reason is wound around the shaft portion 2a between the yarn control cams 13 and 14. The looper yarn L is cut only when Therefore, the reliability of the sewing machine is further improved.
Further, the notch 15b cuts the looper yarn L before a large amount of looper yarn L is wound with the rotation of the lower shaft 2. At this time, the end portion L2 on the looper yarn supply source side of the looper yarn L cut by the notch 15b is swept by the yarn control cam 14 and is not wound around the shaft portion 2a again. As a result, the amount of looper yarn L wound around the shaft portion 2a becomes very small, and the looper yarn L wound around can be easily removed. Therefore, the conventional problem that a large amount of the looper yarn L is wound and the removal of the looper yarn L becomes very complicated can be solved, and the reliability and comfort of the sewing machine are greatly improved.
Furthermore, since the notch 15b is provided at the inner edge portion of the elongated hole portion 15a provided in the yarn guide member 15, it is necessary to secure a member for fixing the blade and a space for installing the blade as in the prior art. As a result, the degree of freedom in designing the sewing machine is further improved.
Further, since the notch 15b does not require a mechanism for repeating contact and non-contact with the looper yarn L as in the prior art, the configuration for cutting the looper yarn L becomes extremely simple, and the sewing machine The sewing machine that can cut the looper yarn L when the looper yarn L is wound can be provided at an extremely low cost.

  Further, the yarn catching member 20 is provided at a position closer to the looper yarn supply source than the outer periphery of the yarn control cam 14 and between the outer periphery and the lower shaft 2a. That is, the end of the looper yarn L that has fallen to the side surface of the yarn control cam 14 on the supply source side of the looper yarn L can be captured. As a result, the looper yarn L that is cut with respect to the gap 2b formed between the side surface on the supply source side of the looper yarn L of the yarn control cam 14 and the bearing 4 of the lower shaft 2 provided on the side surface side. It is possible to prevent the end portion L2 from being wound. Therefore, it is possible to solve the problem that a large amount of the looper yarn L is wound around the gap 2b and the removal of the looper yarn L becomes very complicated, and the reliability and comfort of the sewing machine are greatly improved.

Furthermore, since the notch 15b is a recess provided in the inner edge of the elongated hole 15a provided in the yarn guide member 15, the wound looper yarn L can be cut without providing a separate blade or the like. Therefore, it is not necessary to secure a member for fixing the blade and a space for installing the blade as in the prior art, and the degree of freedom in designing the sewing machine is further improved. Further, the thread trimming means can be provided without making a significant design change to the conventional thread control device. Therefore, the thread trimming means can be provided at a lower cost.
Furthermore, since the notch 15b cuts the yarn by hooking the yarn, the inner edge of the notch 15b need not be processed into a blade shape. Therefore, the thread trimming means can be provided at a lower cost. Although the inner edge portion of the notch 15b functions as a thread trimming means without being processed into a blade shape, it is more desirable to process the inner edge portion of the notch 15b into a blade shape.

(Second Embodiment)
Next, a second embodiment different from the above-described embodiment will be described in detail. In addition, the same code | symbol is attached | subjected about the structure similar to the above-mentioned embodiment, and detailed description is abbreviate | omitted.
FIG. 9 is an explanatory diagram showing a configuration of a yarn control device 10A according to the second embodiment. FIG. 10 is an explanatory view of the configuration of the yarn control device 10A according to the second embodiment as viewed from the direction along the lower shaft 2.
As shown in FIGS. 9 and 10, the yarn control device 10A according to the second embodiment includes a cylindrical portion 14a provided integrally with the yarn control cam 14 on the side surface of the yarn control cam 14 on the looper yarn supply source side. The blade portion 21a is provided with a thread trimming knife 21 provided close to the outer peripheral portion of the cylindrical portion 14a.

In the sewing machine equipped with the yarn control device 10A, the end portion L1 of the looper yarn L caused by the yarn breakage of the looper yarn L that occurs closer to the looper than the yarn control cam 13 is formed by two yarn control cams 13, 14, the looper thread L is cut by the notch 15b provided in the inner edge 15d on the lower shaft side of the elongated hole 15a of the thread guide member 15 when the loop 2 is wound around the shaft 2a. This is the same as the yarn control device 10 of the embodiment.
Further, in the sewing machine equipped with the yarn control device 10A, the end portion L2 on the looper yarn supply source side of the end portion of the looper yarn L cut by the notch 15b is located in the gap between the yarn control cam 14 and the rotating portion 16. The yarn path in the case of falling is the same as that of the yarn control device 10 of the above-described embodiment. Further, the end portion L1 of the looper yarn L may be swept by the yarn control cam 14 without being wound around the shaft portion 2a and fall into the gap between the yarn control cam 14 and the rotating portion 16. It is the same as the device 10.

The cylindrical portion 14 a is a cylindrical member provided integrally with the yarn control cam 14 on the side surface of the yarn control cam 14 on the looper yarn supply source side. That is, the circumferential portion 14 a rotates with the rotation of the yarn control cam 14. Moreover, it is provided so that the bearing 4 may be inserted inside the cylindrical end part extended in the looper yarn supply source side. That is, the gap 2b generated between the yarn control cam 14 and the bearing 4 is located inside the circumferential portion 14a. Therefore, the cylindrical portion 14a functions as a “first cylindrical portion”. The bearing 4 functions as a “second cylindrical portion”.
As shown in FIG. 10, the thread trimming knife 21 has a blade portion 21a that is disposed in proximity to the circumferential outer periphery of the cylindrical portion 14a. The thread trimming knife 21 is fixedly supported on the sewing machine frame.

FIG. 11 is an explanatory view showing a mechanism in which the looper thread L wound around the cylindrical portion 14a is cut by the thread trimming knife 21. FIG.
The end portion L1 on the looper yarn supply source side when the looper yarn L is broken or the end portion L2 on the looper yarn supply source side of the looper yarn L cut by the notch 15b is shown in FIG. Similarly to (b), it may fall into the gap between the yarn control cam 14 and the rotating portion 16. In this case, the end portion L1 or L2 of the looper yarn L abuts on the outer peripheral portion of the cylindrical portion 14a. At this time, if the thread control cam 14 is rotating because the sewing operation by the sewing machine is continued, the looper thread L is dragged by the rotation of the circumferential portion 14a and is wound around the cylindrical portion 14a.

As shown in FIG. 11, the looper yarn L wound around the cylindrical portion 14a is wound along the circumferential outer peripheral portion of the cylindrical portion 14a. However, the looping of the looper yarn L proceeds to the outer peripheral portion of the cylindrical portion 14a. When it becomes so that it is wound twice, the looper yarn L wound so as to increase the thickness to the outside of the outer peripheral portion of the cylindrical portion 14a comes into contact with the blade portion 21a of the thread trimming knife 21, and the looper yarn L Is disconnected. Therefore, the thread trimming knife 21 functions as a “cutting member”.
Thereafter, the looper yarn L wound around the cylindrical portion 14a with tweezers or the like is removed.

  In other words, when the sewing machine equipped with the thread trimming device 10A causes the thread breakage of the looper thread L on the side closer to the looper than the thread control cam 13 during the sewing operation, the end L1 on the looper thread supply source side has two pieces. When wound around the shaft portion 2a between the yarn control cams 13 and 14, the notch 15b cuts the looper yarn L wound around the shaft portion 2a as in the above-described embodiment. Further, the end portion L2 on the looper yarn supply source side of the end portion of the looper yarn L cut by the notch 15b falls into the gap between the yarn control cam 14 and the rotating portion 16 and winds around the circular head portion 14a. For this purpose, the blade portion 21a of the thread trimming knife 21 cuts the looper thread L. Further, when the end portion L1 of the looper yarn L is swept by the yarn control cam 14 without being wound around the shaft portion 2a, falls into the gap between the yarn control cam 14 and the rotating portion 16, and is wound around the cylindrical portion 14a. In addition, the blade portion 21a of the thread trimming knife 21 cuts the looper thread L. This prevents a problem that the looper yarn L is wound around each part of the lower shaft 2 where the looper yarn L is likely to be wound, such as the shaft portion 2a and the gap 2b.

(Effects of the sewing machine according to the second embodiment)
According to the second embodiment, when the looper yarn L falls in the gap between the yarn control cam 14 and the rotating portion 16, the looper yarn L is wound around the outer peripheral portion of the cylindrical portion 14a. Further, the end of the cylindrical portion 14a on the looper yarn supply source side is arranged so that the bearing 4 is inserted inside thereof. That is, the gap 2b generated between the side surface of the yarn control cam 14 on the looper yarn supply source side and the bearing 4 is located inside the cylindrical portion 14a. As a result, the end portion L1 or L2 of the looper yarn L cut into the gap 2b can be prevented from being wound.
At this time, since the blade portion 21a of the thread trimming knife 21 cuts the looper yarn L wound around the circumferential portion 14a, the looper yarn L is cut without being wound around the outer peripheral portion of the cylindrical portion 14a. Therefore, when the looper yarn L breaks, the looper yarn L is wound around the gap 2b in a large amount, and the problem that the removal of the looper yarn L becomes very complicated can be solved. The characteristics are greatly improved.

(Other)
FIG. 12 is a side view showing the configuration of another embodiment of the yarn guide member.
The thread trimming means in the above-described embodiment and the second embodiment is a notch 15b as a recess provided in the inner edge of the elongated shaft 15a of the thread guide member 15 on the lower shaft side. Any mechanism can be used as long as it is capable of being hooked and cut by the looper yarn L that moves so as to be in sliding contact with the inner edge when it is wound around 2a. For example, as shown in FIG. 9, a convex portion 15 </ b> Ab provided on the inner edge portion on the lower shaft side of the elongated hole 15 </ b> Aa of the yarn guide member 15 </ b> A may be used. Of the configuration of the yarn control device using the yarn guide member 15A, the configuration other than the yarn guide member 15A is the same as that of the yarn control device 10 in the above-described embodiment. Further, in order to prevent the looper thread L caught in the recess 15Ab from slipping out of the recess 15Ab before being cut, the side of the recess 15Ab on the side where the looper thread L is locked and the bottom hole 15a It is desirable that the angle of the locking portion 15Af formed by the inner edge portion 15Ad on the shaft side is greater than 0 degree and equal to or less than a right angle.
Also in this configuration, as in the above-described embodiment, the convex portion 15Ab is a convex portion provided at the inner edge portion of the elongated hole portion 15Aa provided in the yarn guide member 15A, and therefore a separate blade or the like is provided. The looper yarn L that is wound without being caught can be hooked and cut. Therefore, it is not necessary to secure a member for fixing the blade and a space for installing the blade as in the prior art, and the degree of freedom in designing the sewing machine is further improved. Further, the thread trimming means can be provided without making a significant design change to the conventional thread control device. Therefore, the thread trimming means can be provided at a lower cost.

Further, the inner peripheral portion of the notch 15b of the yarn guide member 15 may be shaped like a blade. As a result, the looper yarn L caught in the notch 15b is more suitably cut.
Further, the side portion of the concave portion 15Ab of the yarn guide member 15A that engages the looper yarn L may be shaped like a blade. Thereby, the looper yarn L caught on the locking portion 15Af is more suitably cut. At this time, in addition to the side portion of the concave portion 15Ab on the side where the looper yarn L is locked, the inner edge portion 15Ad on the lower shaft side in the vicinity of the locking portion 15Af is also shaped like a blade, so that the looper yarn L is more suitably used. Can be cut off.

Further, the yarn catching member does not necessarily have to be provided on the outer peripheral surface of the bearing 4, and the position where the ends L1 and L2 of the looper yarn L can be caught so that the ends L1 and L2 of the looper yarn L do not fall into the gap 2b. If it is in. For example, the yarn catching member may be provided on the upper surface of the sewing machine frame that is fixed above and provided at a position that is always above the outer periphery of the yarn control cam 14 and above the gap 2b.
Further, in the above-described embodiment, the yarn catching member 20 catches the cut ends L1 and L2 of the looper yarn L by the strip-like raising along the arc of the outer peripheral portion of the bearing 4, but the yarn catching member Any configuration can be used as long as it can capture the end of the cut yarn. For example, the surface of the yarn catching member may be a material having adhesiveness.

It is a perspective view which shows the structure of the thread | yarn control apparatus with which the sewing machine by this invention was equipped. It is explanatory drawing which shows the positional relationship of a thread | yarn guide member and a lower shaft. It is a perspective view which shows the thread | yarn control apparatus at the time of the large diameter part of a thread | yarn control cam contacting the looper thread | yarn. It is explanatory drawing which shows the path | route of the looper thread | yarn in the inner edge part of the long hole part of a thread | yarn guide member. FIG. 4A is an explanatory diagram showing the route of the looper yarn before passing over the notch. FIG. 4B is an explanatory diagram showing a route of the looper yarn when passing over the notch. FIG. 4C is an explanatory diagram showing the looper yarn path after passing over the notch. It is explanatory drawing which shows the displacement of a looper yarn when the thread breakage of a looper yarn has occurred. FIG. 5 (a) is an explanatory view showing the moment when the looper yarn breaks on the looper side with respect to the threading portion closer to the looper. FIG. 5B is an explanatory diagram showing the looper yarn swept by the yarn control cam. FIG. 5C is an explanatory view showing a state in which the looper yarn is wound around the shaft portion between two yarn control cams. It is explanatory drawing which shows the path | route of a looper thread | yarn with respect to the long hole part of a thread | yarn guide member when a looper thread | yarn is wound around the axial part between two thread | yarn control cams. FIG. 6A is an explanatory diagram showing the looper yarn path before passing through the notch arrangement position. FIG. 6B is an explanatory view showing the route of the looper yarn caught in the notch. FIG. 6C is an explanatory diagram showing a route of the looper yarn pulled in two directions with the notch serving as a fulcrum. It is a perspective view which shows the thread | yarn control apparatus which rotated the rotation part upwards. It is explanatory drawing which shows the path | route of the edge part by the side of the looper yarn supply source of the looper yarn cut | disconnected by the notch. FIG. 8A is an explanatory view showing the moment when the looper yarn is cut by the notch. FIG. 8B is an explanatory diagram showing the looper yarn swept by the yarn control cam. FIG. 8C is an explanatory view showing a state in which the end portion of the looper yarn is caught by the yarn catching member. It is explanatory drawing which shows the structure of the thread | yarn control apparatus by 2nd Embodiment. It is explanatory drawing which looked at the structure of the thread | yarn control apparatus by 2nd Embodiment from the direction along the lower axis. It is explanatory drawing which shows the mechanism in which the looper thread wound around the cylindrical part is cut | disconnected by the thread trimming knife. It is a side view which shows the structure of the thread | yarn guide member in other embodiment. It is explanatory drawing which shows the positional relationship of the conventional thread | yarn control apparatus and a looper thread | yarn. FIG. 13A is an explanatory diagram showing the position of the looper thread during normal sewing. FIG. 13B is an explanatory diagram showing the position of the looper yarn in a state where the looper yarn is wound around the shaft portion of the gap formed between the two yarn control cams.

Explanation of symbols

2 Lower shaft 3, 4 Bearing 5 Thread path section 10 Thread control device 11, 12 Threading section 13, 14 Thread control cam 15 Thread guide member 16 Rotating section 20 Thread catching member

Claims (7)

A lower shaft that is rotated by the rotation of the sewing machine motor;
A looper that swings in conjunction with the rotation of the lower shaft;
Two threaders,
Two thread control cams that are arranged between the two threading parts and are outer peripheral cams provided on the lower shaft so that the looper thread across the two threading parts is in sliding contact with the outer peripheral part;
A yarn provided between the two yarn control cams and inserted with the looper yarn slidingly contacting each yarn control cam, and provided with a long hole portion for reciprocating the looper yarn along a predetermined direction. A guide member,
In a sewing machine that applies tension to the looper thread by changing the diameter of the two thread control cams,
The yarn guide member includes a yarn cutting means for cutting the looper yarn in the middle of the inner edge portion on the lower shaft side, out of two inner edge portions along the longitudinal direction of the elongated hole portion. Sewing machine.   The looper yarn supply source side is fixed to the sewing machine frame at a position closer to the looper yarn supply source side than the yarn control cam and from the outer periphery of the yarn control cam to the lower shaft. The sewing machine according to claim 1, further comprising a yarn catching member that catches the end portion.   A blade provided integrally with a first cylindrical portion through which the lower shaft is inserted on the side surface on the looper yarn supply source side of the yarn control cam on the looper yarn supply source side, and is disposed close to the outer peripheral surface of the first cylindrical portion. The sewing machine according to claim 1, further comprising a cutting member that cuts the looper yarn by a portion.   A second cylindrical portion that is fixed to the sewing machine frame and is inserted through the lower shaft is provided, and one end portion of the second cylindrical portion is inserted inside the end portion on the looper yarn supply source side of the first cylindrical portion. The sewing machine according to claim 3, wherein the sewing machine is arranged.   The thread trimming means is a thread hooking section for hooking the looper thread by a change in diameter accompanying rotation of the thread control cam and further cutting the looper thread by a change in diameter. To 4. The sewing machine according to any one of items 1 to 4.   The sewing machine according to any one of claims 1 to 5, wherein the thread trimming means is a recess provided in the inner edge.   The sewing machine according to any one of claims 1 to 5, wherein the thread trimming means is a convex portion provided at the inner edge portion.

Images