JP7481893B2 - sewing machine - Google Patents

Description

The present invention relates to a sewing machine equipped with a threading device for threading an upper thread through a needle hole provided at the tip of a needle.

For example, Patent Document 1 below is known as a sewing machine equipped with a threading device for threading the upper thread through an eye provided at the tip of the needle. As shown in Figures 2 and 4 of Patent Document 1, the threading device of Patent Document 1 is configured to allow threading by passing a hook-shaped member through the eye of the needle, hooking the upper thread on the hook, and pulling the hook-shaped member out of the eye. However, to thread the needle using this device, as shown in Figure 2 of the same document, the operator must hold the thread with one finger and press down a lever with the other. In other words, both hands must be used to thread the needle, which is cumbersome.

A threading device that solves these problems and improves workability has also been proposed. For example, in the following Patent Document 2, as shown in Figures 1-2 and 8-10 of the same document, the upper thread is hooked on the thread holding mechanism (70) in preparation for threading, and when the operating lever (47) is pressed down, the hook (32) passes through the needle hole in conjunction with this, and the thread holding mechanism guides the upper thread to the hook, where the upper thread is captured by the hook. After that, when the pressure on the operating lever is released and it moves upward, the hook comes out of the needle hole with the upper thread captured, and the upper thread is threaded. In other words, the threading device of Patent Document 2 is easy to use because threading can be performed by simply operating the operating lever, that is, by operating it with only one hand.

Japanese Patent Application Laid-Open No. 4-64386 JP 2006-158412 A Japanese Patent Application Laid-Open No. 8-173678

However, in the sewing machine of Patent Document 2, the upper thread is threaded on the thread holding mechanism, so as shown in Figures 1 and 2 of the same document, the thread holding mechanism is always in a state where it protrudes from the underside of the sewing machine cover (F). This makes it difficult to see the state of the needle sewing the fabric, and the gap to the needle plate becomes narrow, making it difficult to perform sewing work.

On the other hand, the above-mentioned Patent Document 3 shows a sewing machine in which the threading device is housed inside the sewing machine cover, and the sewing machine cover is provided with a groove for threading the internal threading device. However, providing a groove in the sewing machine cover impairs the cover's functions of protecting the internal structure and preventing dust from entering. In addition, simply threading the thread through the groove also poses the problem that it is difficult to determine whether the thread is correctly threaded through the threading device inside the groove. Furthermore, as shown in Figure 2 of the same document, this sewing machine also does not solve the problems of visibility and workability that are present in the sewing machine of Patent Document 2, because the part where the groove (12) is provided protrudes downward from the actual sewing machine cover (2).

In view of these problems, the present invention aims to provide a sewing machine that makes it easy to visually check the state of sewing the fabric with the needle, makes sewing work easy, and also makes it easy to thread the fabric.

The present invention provides a sewing machine equipped with a threading device which comprises a first thread holding portion and a threading hook which approach a needle hole at the tip of a needle from one side and the other side respectively while descending toward the needle hole, and which captures the upper thread held by the first thread holding portion which has approached the needle hole, thereby inserting the upper thread into the needle hole. The present invention provides a sewing machine equipped with a threading device which comprises a first thread holding portion and a threading hook which descend toward a needle hole at the tip of a needle while approaching the needle hole from one side and the other side respectively, and which comprises a second thread holding portion which is provided on a cover which covers the threading device and which holds the upper thread in a threading preparation stage , and which does not hold the upper thread in the threading preparation stage and which holds the upper thread and releases the upper thread from the second thread holding portion as the threading device descends, and which comprises a support body and a first thread holding body which is displaced between an open state in which it is separated from the support body and a clamping state in which it approaches the support body and can clamp the upper thread, and which is configured to displace from the open state to the clamping state as the threading device descends .

It is also preferable that the first thread holding portion is provided with a threading arm that comes into contact with the upper thread as the threading device descends, and that the threading arm and the first thread holding body displaced to the clamped state cooperate to form a horizontal portion on the upper thread.

The threading device preferably includes a rotating part that rotates the first thread holding part, and the horizontal part is moved to a position facing the needle hole by lowering and rotating the first thread holding part.

It is preferable that the holding force with which the second thread holding portion holds the upper thread is set to be weaker than the holding force with which the first thread holding portion holds the upper thread.

In the sewing machine of the present invention, the upper thread can be inserted into the needle hole by the first thread holding part and the threading hook provided in the threading device, making threading easy. In addition, a second thread holding part that holds the upper thread in the threading preparation stage is provided on the sewing machine cover that covers the threading device, and the above-mentioned first thread holding part clamps and holds the upper thread as it descends toward the needle hole when threading, and releases the upper thread from the second thread holding part, but is located above and does not hold the upper thread when the threading device is not in use, including the threading preparation stage. In other words, the area around the needle is not blocked during sewing, making it easier to see the sewing state and improving workability.

1 is an external view showing an embodiment of a sewing machine according to the present invention; FIG. 2 is a perspective view of the sewing machine shown in FIG. 1 with the face plate removed, showing the internal threading device and needle drive device. FIG. 3 is an exploded perspective view of the threading device and the needle drive device in FIG. 2 . 5A and 5B are enlarged perspective views showing the periphery of the tip of the support, in which FIG. 5A shows the state before the needle thread is held, and FIG. 5B shows the state after the needle thread is held. 5A to 5C are explanatory diagrams relating to a threading operation by the threading device. 6 is an explanatory diagram of a threading operation by the threading device performed subsequent to the state shown in FIG. 5 . 7 is an explanatory diagram of a threading operation by the threading device performed subsequent to the state shown in FIG. 6 . 8 is an explanatory diagram of a threading operation by the threading device performed subsequent to the state shown in FIG. 7 . 9 is an explanatory diagram of a threading operation by the threading device performed subsequent to the state shown in FIG. 8 .

An embodiment of the sewing machine according to the present invention will be described below with reference to the drawings. Note that the X, Y, and Z directions in the following description refer to the directions along the arrows X, Y, and Z shown in the drawings, with the left-right direction when the sewing machine 1 is viewed from the front being the X direction, the depth direction (front-back direction) being the Y direction, and the height direction (up-down direction) being the Z direction.

As shown in FIG. 1, the sewing machine 1 of this embodiment is equipped with a sewing machine cover 2, which is an exterior member that covers the entire sewing machine 1. The sewing machine cover 2 of this embodiment is equipped with a sewing machine cover main body 2a that mainly covers the right and central parts of the sewing machine 1, and a face plate 2b that mainly covers the left part of the sewing machine 1, and a groove-shaped thread path 2c is provided near the boundary between the sewing machine cover main body 2a and the face plate 2b. A thread spool support part 3 that supports a thread spool s is provided on the upper right side of the sewing machine cover 2, and a needle bar thread hook part 4, a needle 5 (having a needle hole 5a at the tip), a thread hook spring 6 (see FIG. 2), and a lower part of a lever 7 (a pressing part 7a to be described later) are provided on the lower left side of the sewing machine cover 2 in a state exposed from the face plate 2b. Note that the thread hook spring 6 of this embodiment has one end fixed to the lower surface of the face plate 2b with a screw or the like as shown in the figure, and the upper thread t from the thread spool s can be clamped between the other end and the face plate 2b. Although not shown in the figure, a thread cutting blade for cutting the upper thread t is provided near the threading spring 6.

When sewing cloth with the sewing machine 1, the operator must perform a threading operation in which the upper thread t is pulled from the thread spool s and passed through the needle hole 5a as a preparation step. Details will be described later, but in the sewing machine 1 of this embodiment, the operator passes the upper thread t from the thread spool s through the thread path 2c and then passes it through the needle bar threading section 4, and then the threading operation is performed by holding it between the threading spring 6 and the face plate 2b. In the following description, the threading spring 6 and the face plate 2b are collectively referred to as the second thread holding section h2. After that, when the lever 7 is pressed down, the threading device 9 acts on the needle drive device 8 (described later), and the upper thread t can be automatically passed through the needle hole 5a.

The configuration of the needle drive device 8 will now be described in detail with reference to Figures 2 and 3. Note that the exploded perspective view in Figure 3 is intended to explain the connections between the various parts, and does not strictly depict the assembly procedure. There are some parts shown as having been installed first, which will be installed later during assembly.

The needle drive device 8 of this embodiment includes a needle bar 10 that holds the needle bar threader 4 at its lower end and the needle 5 below the needle bar threader 4, a needle bar support 11 that supports the needle bar 10 so that it can slide up and down, and a threading positioning plate 12 that is fixed to the middle of the needle bar 10. The needle bar support 11 of this embodiment is formed by bending a metal plate into a predetermined shape, and a circular shaft hole 11a that penetrates the needle bar support 11 in the Y direction is provided at its upper part. In addition, an amplitude connecting part 11b that penetrates the needle bar support 11 in the Y direction is provided at the middle part of the needle bar support 11. A planar positioning part (needle drive device side positioning part) 11c is provided on the left side of the needle bar support 11. The threading positioning plate 12 includes a protrusion 12a that extends in the X direction and a groove part 12b located above the protrusion 12a and on the base side of the protrusion 12a.

The needle drive device 8 of this embodiment is equipped with an upper shaft 13 rotated by a motor (not shown) as a mechanism for moving the needle 5 up and down, and a crank portion 14 that is provided between the upper shaft 13 and the needle bar 10 and converts the rotational motion of the upper shaft into reciprocating linear motion. The needle bar 10 moves up and down as the motor rotates, thereby moving the needle 5 up and down. The sewing machine arm 15 is a frame member that corresponds to the skeleton of the sewing machine.

The needle drive device 8 also includes a cylindrical shaft 16 protruding from the sewing machine arm 15 in the Y direction as a mechanism for swinging the needle 5 left and right, and an amplitude mechanism (not shown) connected to the amplitude connection part 11b. The shaft 16 is inserted through the shaft hole 11a of the needle bar support 11 to rotatably support the needle bar support 11. When the amplitude mechanism is driven, the needle bar support 11 swings left and right around the shaft 16, so that the needle 5 also swings left and right via the needle bar 10 supported by the needle bar support 11. By combining the stitch formation by the up and down movement of the needle 5 and the swinging movement of the needle 5, zigzag stitching, pattern stitching, character stitching, etc. can be performed. The shaft 16 rotatably supports the threading device 9, which also rotates the first thread holding part h1 described later, so that the shaft 16 is sometimes referred to as the "rotating part" in this specification.

As shown in the partially enlarged view of FIG. 3, the threading device 9 is equipped with a hook-shaped threading hook 17 that is open at the bottom. Details will be described later, but the threading hook 17 captures the upper thread t after being inserted into the needle hole 5a, and then passes the upper thread t through the needle hole 5a by removing it from the needle hole 5a. The threading hook 17 is provided at one end (one end in the left-right direction in FIG. 3) of the threading body 18 shown in FIG. 3. The threading body 18 is fixed to the threading shaft 19, and in this embodiment, as shown in FIG. 3, the other end in the left-right direction is fixed to the lower end of the threading shaft 19. The threading shaft 19 is supported to be slidable in the vertical direction relative to the support body 20 and rotatable around the axis of the threading shaft 19, and is formed in a roughly cylindrical shape in this embodiment. The support body 20 is supported to be slidable in the vertical direction relative to the support base 21, and the support base 21 is supported to be rotatable on the shaft 16.

As described above, the threading shaft 19 is supported by the support 20 so that it can slide up and down and rotate. In this embodiment, the support 20 is provided with an upper bearing portion 20a and a lower bearing portion 20b with circular holes that support the threading shaft 19 (see the view of the arrow A in FIG. 3). As shown in FIG. 3, the threading shaft 19 is provided with a first compression spring 22. When the threading shaft 19 is supported by the support 20, the first compression spring 22 is interposed between the lower surface of the lower bearing portion 20b and the upper surface of the threading body 18, and biases the threading body 18 in a direction that moves it away from the support 20. When the threading shaft 19 is supported by the support 20, the retaining ring 23 attached to the threading shaft 19 is in a position that contacts the upper surface of the lower bearing portion 20b, and holds the threading shaft 19 against the support 20.

The support base 21 in this embodiment is a mechanism for rotatably supporting the shaft 16. The shaft 16 can be inserted through the support base 21, which has a circular shaft hole 21b that passes through a U-shaped bent portion provided at the top of the support base 21.

The threading shaft 19 also has cylindrical threading pins (front threading pin 19a and rear threading pin 19b) that protrude in the Y direction in FIG. 3. The front threading pin 19a penetrates the support base 21 in the thickness direction and is inserted into a slit portion 21a that extends along the longitudinal direction of the support base 21, and is further inserted into a cam hole 20c provided in the support 20. The cam hole 20c in this embodiment is approximately triangular in front view as shown in the partial enlarged view of FIG. 3, and has an upper inner surface 20c1, a lower inner surface 20c2, and a left inner surface 20c3 that extend linearly. The upper inner surface 20c1 and the lower inner surface 20c2 are inclined from top to bottom as they move from left to right. The rear threading pin 19b is linked to the protrusion 12a and groove portion 12b of the threading positioning plate 12, as will be described in detail later.

The support 20 is fitted with a thread holding plate 24 that can rotate around the X direction in FIG. 3. The thread holding plate 24 is sometimes referred to as the "first thread holding body" in this specification. As shown in FIG. 4(a), the thread holding plate 24 extends parallel to the YZ plane and the ZX plane, forming an L-shape in a plan view, and is biased by a torsion spring (not shown) in a direction in which the tip 24a is pressed against the back surface 20d of the support 20. The thread holding plate 24 is provided with a protrusion 24b that protrudes in the Y direction, and in the state shown in FIG. 4(a) (the state in which the threading body 18 described later is in the standby position), the protrusion 24b abuts against the support base 21 and inhibits rotation in the biased direction, so that there is a gap between the tip 24a and the back surface 20d (open state). The support 20 is also provided with a threading arm 20e that protrudes in the X direction, and a thread holding groove 20f that extends in the X direction below the threading arm 20e. As described below, the back surface 20d of the support 20, the threading arm 20e, the thread holding groove 20f, and the thread holding plate 24 hold the upper thread t during the middle stage of the threading operation, and in the following description, the back surface 20d, the threading arm 20e, the thread holding groove 20f, and the thread holding plate 24 are collectively referred to as the first thread holding portion h1.

The function will be described later, but the support 20 is provided with a flat needle receiving surface 20g extending in the vertical direction as shown in FIG. 4(a), an insertion hole 20h that crosses the thread holding groove 20f and extends in the Y direction, a first cam portion 20j provided on the surface of the support 20 as shown in FIG. 3, and a flat positioning portion (threading side positioning portion) 20k located on the right side of the support 20.

The threading device 9 further includes the slide base 25, tension spring 26, and lever 7 shown in FIG. 3, as well as a second compression spring (biasing member) 27 shown in FIG. 5.

The slide base 25 is formed by bending a metal plate into a predetermined shape, and is fixed to the sewing machine arm 15 and a bracket 28 that is immovable relative to the sewing machine arm 15 by screws or the like, as shown in FIG. 3. The slide base 25 has a rectangular slide hole 25a extending along its longitudinal direction, and a spring hook 25b for hooking one end (upper end) of the tension spring 26, and further has a planar second cam portion 25c that is located on the side of the slide base 25 and extends in the vertical direction, as shown in the view of arrow B in FIG. 3. The second cam portion 25c abuts against the first cam portion 20j described above.

The lever 7 is located at its lower part, and is exposed from the face plate 2b when assembled into the sewing machine 1 as shown in FIG. 1. The plate-shaped pressing part 7a is used to be pressed by the operator's finger when threading the needle, and the groove-shaped support connecting part 7b is provided on the upper back side of the plate-shaped pressing part 7a. The front side of the support 20 described above is provided with a cylindrical lever connecting part 20m protruding in the Y direction, and the support connecting part 7b is formed in a shape in which the lever connecting part 20m fits inside. The groove-shaped support connecting part 7b is shaped to extend along the X direction, and the lever connecting part 20m fits into the support connecting part 7b so as to be immovable in the vertical direction, but moves slightly in the horizontal direction (has play). Furthermore, the lever 7 is provided with a cylindrical spring receiving part 7c located at its upper part and protruding in the Y direction. After the spring receiving portion 7c is inserted through the slide hole 25a, it hooks the other end (lower end) of the tension spring 26, so that the lever 7 is biased upward by the tension spring 26.

As shown in FIG. 5, the second compression spring 27 biases the support base 21, which is rotatably supported by the shaft 16, toward the needle drive device 8. The second compression spring 27 is disposed in a compressed state, for example, between a fixed portion that connects to the sewing machine arm 15 and the left side surface of the support base 21, and biases the support base 21 toward the needle drive device 8 by the biasing force generated when the spring is restored to its original length.

Next, the threading operation of the sewing machine 1 of this embodiment will be described with reference to Figures 5 to 9. Note that in order to explain the interlocking state between the first cam portion 20j and the second cam portion 25c, Figures 5 to 9 show the second cam portion 25c in a simplified manner.

First, the threading operation performed as a preparation for the threading operation will be described with reference to Figures 1 and 5. The operator pulls out the upper thread t from the thread spool s set in the sewing machine 1, passes it through the thread path 2c, and then hooks it on the needle bar threading section 4, and then hooks it on the threading spring 6, so that the upper thread t is sandwiched between the threading spring 6 and the face plate 2b. As a result, the upper thread t is held by the second thread holding section h2, which is composed of the threading spring 6 and the face plate 2b. A thread cutting blade (not shown) is provided near the threading spring 6, and the upper thread t can be cut when it is hooked on the threading spring 6, so that the remaining thread length (the length of the upper thread t from the threading spring 6 to the cut end) can be shortened as shown in the partial enlarged view of Figure 5. In other words, Figures 1 and 5 show the state in which the threading operation is completed (threading preparation stage). In this state, the first thread holding section h1 is located directly above the upper thread t as shown in the figure. In addition, the thread holding plate 24 has a gap between the tip 24a and the back surface 20d because the protruding portion 24b is in contact with the support base 21. Although the threading device 9 is biased toward the needle drive device 8 by the biasing force of the second compression spring 27, as shown in the figure, in the threading preparation stage, the first cam portion 20j is in contact with the second cam portion 25c, and the needle drive device 8 and the threading device 9 are separated from each other. Note that FIG. 5 shows a state in which the lever 7 is not pressed down and the support 20 is in the uppermost position, and the position of the support 20 (threading device 9) at this time is referred to as the standby position. For the following explanation, the amount by which the support 20 has descended from the standby position, that is, the amount by which the lever 7 has been pressed down, is indicated by the symbol L in the figure, based on the position of the lever connecting portion 20m that connects to the lever 7.

After the threading operation is completed, the operator presses down the lever 7 to perform the threading operation. FIG. 6(a) shows a schematic diagram of the state in which the lever 7 is pressed down by a distance S2 from the state shown in FIG. 5 (where the lever 7 is at height L). As the lever 7 is pressed down, the support 20 also descends, and the upper thread t enters the gap between the tip 24a of the thread holding plate 24 and the back surface 20d of the support 20. As the support 20 descends, the support base 21 separates from the protruding portion 24b, and the thread holding plate 24 becomes rotatable toward the back surface 20d (clamped state). As described above, the thread holding plate 24 is biased toward the back surface 20d by a torsion spring (not shown), so the thread holding plate 24 rotates toward the back surface 20d of the support 20, and the upper thread t is clamped and held between the tip 24a and the back surface 20d. At this time, the upper thread t also comes into contact with the threading arm 20e as shown in FIG. 4B, is captured, and is guided to the thread holding groove 20f. The upper thread t is held by the support 20, the thread holding plate 24, the threading arm 20e, and the thread holding groove 20f so that a horizontal portion t1 is formed between the thread holding plate 24 and the threading arm 20e (in this embodiment, the upper thread t is also inserted into the thread holding groove 20f). Note that the "horizontal portion" of the upper thread t does not mean that a part of the upper thread t extends strictly horizontally, but is not limited to being horizontal as long as it is at an angle that allows the threading hook 17 to be captured by the threading hook 17 as described later. In this state, the upper thread t is held by the first thread holding portion h1 constituted by the thread holding plate 24 and the like, and is also held by the second thread holding portion h2 constituted by the threading spring 6 and the like, as shown in FIG. 6A. The force that holds the upper thread t in the second thread holding portion h2 (the biasing force of the thread hook spring 6 that presses the upper thread t against the face plate 2b) is weaker than the force that holds the upper thread t in the first thread holding portion h1 (the biasing force of a torsion spring (not shown) that rotates the thread holding plate 24 toward the back surface portion 20d). In other words, the upper thread t is easier to come off from the second thread holding portion h2 than from the first thread holding portion h1.

When the lever 7 is then pushed down by a distance S3 as shown in FIG. 6(b), the support 20 descends, separating the first cam portion 20j from the second cam portion 25c, and the connection between the first cam portion 20j and the second cam portion 25c is released. The threading device 9 rotates toward the needle drive device 8 by the biasing force of the second compression spring 27 and approaches it. The threading side positioning portion 20k of the support 20 and the needle drive device side positioning portion 11c of the needle bar support 11, which were described with reference to FIG. 3, come into contact when the threading device 9 approaches the needle drive device 8, as shown in FIG. 6(b), and the approaching threading device 9 and the needle drive device 8 can be connected in a predetermined positional relationship. In addition, the upper thread t held by the first thread holding portion h1 is guided to the vicinity of the needle 5 by the rotation of the threading device 9. In this state, the horizontal portion t1 of the upper thread t held by the first thread holding portion h1 is positioned in front of the needle 5 in a direction perpendicular to the needle 5. Incidentally, the path of the upper thread t from the needle bar threading portion 4 to the threading spring 6 shown in FIG. 6(a) is curved significantly downward because the support 20 descends in FIG. 6(b). That is, the amount of thread required between the needle bar threading portion 4 and the threading spring 6 increases, and the thread is pulled out from both the side where the thread spool s is located and the side where the threading spring 6 is located to compensate for the increased amount of thread. Here, the upper thread t is pulled out on the side where the thread spool s is located because the amount of thread on the thread spool s is abundant. On the other hand, the remaining thread is shorter on the side where the threading spring 6 is located, and the holding force of the second thread holding portion h2 to hold the upper thread t is weaker than the holding force of the first thread holding portion h1 to hold the upper thread t. Therefore, the upper thread t that was held by both the first thread holding part h1 and the second thread holding part h2 in the state shown in FIG. 6(a) is released from the second thread holding part h2 in the state shown in FIG. 6(b) and is held only by the first thread holding part h1.

In the state shown in FIG. 6(b), the front side threading pin 19a of the threading shaft 19 shown in FIG. 3 is located to the right of the cam hole 20c, and the rear side threading pin 19b is located above the protrusion 12a of the threading positioning plate 12. In addition, the threading hook 17 provided at the lower end of the threading shaft 19 via the threading body 18 is located away from the support body 20. The support body 20 is biased upward by the first compression spring 22 arranged between the lower surface of the lower bearing portion 20b and the upper surface of the threading body 18, and is at a height where the upper surface of the lower bearing portion 20b contacts the stop ring 23.

When the lever 7 is further pressed down to reach the distance S4 as shown in FIG. 7(a), the upper thread t, which has been guided to the vicinity of the needle 5 by the first thread holding portion h1, descends to the vicinity of the needle hole 5a. However, the threading shaft 19, which has descended the same amount in conjunction with the support 20 up to this point, is prevented from descending any further when the back side threading pin 19b abuts against the protrusion 12a of the threading positioning plate 12, as shown in the partial enlargement at the top of FIG. 7(a). The position at which the threading shaft 19 is prevented from descending is set so that the threading hook 17 and the needle hole 5a are aligned in the vertical direction. On the other hand, the support 20 can move downward while compressing the first compression spring 22, as shown in the partial enlargement at the bottom of FIG. 7(a). Therefore, the support 20 descends together with the lever 7 while leaving the threading shaft 19 behind, so that the cam hole 20c moves downward relative to the front threading pin 19a (the cam hole 20c is shifted downward relative to the front threading pin 19a). The amount of shift at this time is indicated by a distance I4 in FIG. 7(a). In this state, the first thread holding part h1 also moves downward by the distance I4 relative to the threading hook 17 fixed to the threading shaft 19 (the first thread holding part h1 is shifted downward relative to the threading hook 17). When the cam hole 20c moves downward relative to the front threading pin 19a, the upper inner surface 20c1 of the cam hole 20c presses against the front threading pin 19a, and the threading shaft 19 rotates so that the front threading pin 19a moves to the left (the threading shaft 19 rotates clockwise when viewed from above). Therefore, the threading hook 17 located on the back side of the needle 5 rotates in a direction approaching the needle 5.

7(b) shows a schematic diagram of the state in which the lever 7 is pushed down to a distance S5 and the support 20 reaches its lowest point (the support 20 is in the threading position). As the support 20 descends together with the lever 7, the upper thread t, which has been guided to the vicinity of the needle hole 5a, further descends beyond the needle hole 5a. Meanwhile, as the support 20 descends, the threading shaft 19 rotates further clockwise because the upper inner surface 20c1 of the cam hole 20c further presses against the front threading pin 19a. This rotation causes the threading hook 17 to pass through the needle hole 5a from the back side to the front side, and is further inserted into the insertion hole 20h (see FIG. 4(b)) provided in the support 20. In the state shown in FIG. 7(b), the first thread holding portion h1 has moved downward by a distance I5 relative to the threading hook 17 (the first thread holding portion h1 is shifted downward relative to the threading hook 17). In this state, the back side threading pin 19b enters and fits into the groove 12b provided at the base side of the protrusion 12a.

Figure 8(a) shows a schematic diagram of the state in which the operator releases the lever 7 after pushing it down to the lowest point, and the lever 7 is in the middle of returning to its original standby position due to the biasing force of the tension spring 26 (the lever 7 is at a distance S6). In this state, the lever 7 rises due to the biasing force of the tension spring 26 shown in Figure 3, and the support body 20 also rises accordingly, while the threading shaft 19 stops at that height because the back side threading pin 19b is engaged with the groove portion 12b. As a result, the vertical deviation of the first thread holding portion h1 from the threading hook 17, which was a distance I5 in Figure 7(b), is partially eliminated, and the front side threading pin 19a, which was located near the upper inner surface 20c1 in Figure 7(b), is now located near the lower inner surface 20c2. In addition, since the threading shaft 19 remains stationary and only the support 20 rises, the upper thread t (horizontal portion t1) held by the first thread holding portion h1 crosses the threading hook 17 and is captured by the threading hook 17.

8(b) shows a schematic diagram of the support 20 in a state where it has risen further than the position shown in FIG. 8(a) (the lever 7 is at a distance S7). As the support 20 rises further, the lower inner surface 20c2 of the cam hole 20c presses against the front threading pin 19a, and the threading shaft 19 rotates so that the front threading pin 19a moves to the right in front view compared to the state shown in FIG. 8(a) (the threading shaft 19 rotates counterclockwise when viewed from above). Therefore, the rear threading pin 19b comes out of the groove 12b, and the threading shaft 19 starts to rise in conjunction with the support 20, so that the vertical misalignment of the first thread holding portion h1 with respect to the threading hook 17 is eliminated. Also, as the threading shaft 19 rotates counterclockwise, the threading hook 17 also rotates in this direction and is pulled out of the needle hole 5a. Here, the upper thread t is hooked on the threading hook 17, so the upper thread t is pulled out of the needle hole 5a from the front side to the back side while still hooked on the threading hook 17, and the upper thread t is inserted into the needle hole 5a.

When the support 20 rises further and the lever 7 reaches the distance S8 shown in FIG. 9(a), the first cam portion 20j of the support 20 comes into contact with and rides on the second cam portion 25c, so that the threading side positioning portion 20k and the needle drive device side positioning portion 11c separate, and the threading device 9 rotates around the shaft 16 in a direction away from the needle drive device 8. With this rotation, the support 20 rises and moves away from the needle 5, so that the upper thread t between the threading hook 17 and the first thread holding portion h1 is greatly bent with the needle hole 5a as the bending point. In other words, the amount of thread required between the threading hook 17 and the first thread holding portion h1 increases. On the other hand, in the first thread holding portion h1, as the support 20 rises, the convex portion 24b of the thread holding plate 24 abuts against the support base portion 21 again, so that the thread holding plate 24 rotates in the opposite direction to the biased direction, and a gap is created between the tip portion 24a and the back portion 20d. In other words, the thread holding plate 24 is in an open state, and the upper thread t is released from its hold. Therefore, the upper thread t is released from the first thread holding portion h1.

Figure 9(b) shows a schematic diagram of the state in which the support 20 has risen further from the state shown in Figure 9(a) and returned to the standby position. As the support 20 rises further, the threading hook 17 further pulls up the upper thread t on the side where the first thread holding portion h1 is located, and all of the remaining thread, including the end of the upper thread t, passes through the needle hole 5a. As the threading hook 17 then rises, the upper thread t is also released from the threading hook 17, completing the threading operation.

In this way, according to the sewing machine 1 of this embodiment, the threading operation can be performed by simply pressing down the lever 7. In addition, as shown in FIG. 9(b), in the standby position, the first cam portion 20j of the threading device 9 is in contact with the second cam portion 25c and is separated from the needle drive device 8. In other words, even if the needle drive device 8 swings left and right around the shaft 16 during sewing, such as zigzag stitching, the threading device 9 does not move in conjunction with the needle drive device 8, so noise and vibration can be suppressed. In addition, since there is no need to thread the first thread holding portion h1 of the threading device 9 during the threading operation in preparation for threading, the standby position of the threading device when not in use can be provided inside the sewing machine cover. In other words, the state around the needle can be easily seen while the sewing machine is sewing, making it easier to perform the work.

Although one embodiment of the present invention has been described above, the present invention is not limited to the specific embodiment, and various modifications and alterations are possible within the scope of the spirit of the present invention described in the claims unless otherwise specifically limited in the above description. Furthermore, the effects of the above embodiment are merely examples of the effects resulting from the present invention, and do not mean that the effects of the present invention are limited to the above effects.

For example, in this embodiment, the first thread holding portion h1 is configured with the back portion 20d, the thread hook arm 20e, the thread holding groove 20f, and the thread holding plate 24 so that the upper thread can be reliably captured and held while forming the horizontal portion t1, but a different configuration is also acceptable. In order to capture and hold the upper thread while forming the horizontal portion t1, it is sufficient that the upper thread is supported at at least two points, and for example, the configuration may be the thread holding plate 24 (back portion 20d) and the thread hook arm 20e.

In addition, in this embodiment, the second thread holding portion h2 is provided on the face plate 2b, which is the sewing machine cover, but as long as the second thread holding portion h2 is exposed to the outside of the sewing machine, the member on which it is provided is not limited. Therefore, for example, if a portion of the sewing machine arm is exposed to the outside of the sewing machine, the second thread holding portion h2 may be provided on the exposed portion of the sewing machine arm.

In this embodiment, as shown in FIG. 1, the pressing portion 7a of the lever 7 is exposed from the underside of the panel 2b, but it may be configured to be exposed from another location. For example, a hole through which the lever 7 can move vertically may be provided on the left side surface of the panel 2b, and the pressing portion 7a may be exposed outside the hole. In this case, there is an advantage that the space below the panel 2b is wider, improving visibility. In addition, in this embodiment shown in FIG. 1, a part of the threading device 9 is exposed from the underside of the panel 2b, but this is not limited to the above, and the waiting position may be a position where the threading device 9 is completely stored inside the panel 2b.

The sewing machine 1 of this embodiment is configured so that threading can be done with one hand, but the above technology may be applied to a sewing machine configured so that threading can be done with both hands, as shown in the above-mentioned Patent Document 1, to embody the present invention. The sewing machine 1 of this embodiment has a needle drive device 8 and a threading device 9 that are separate, while the sewing machine shown in Patent Document 2 differs in that the needle drive device and the threading device are integrated as shown in Figure 2 of the same document (the mechanism for driving the hook (32) that performs threading is integrated with the needle bar up-down movement mechanism (13) that moves the needle up and down). However, even in a sewing machine such as the one in Patent Document 2, the above technology can be applied to embody the present invention. In other words, in this embodiment, after the first thread holding part h1 captures and holds the upper thread t by the sliding drive of the threading device 9, the horizontal part t1 of the upper thread t is moved toward the needle hole 5a by using the shaft 16 that rotates the needle drive device 8 as a rotating part that rotates the first thread holding part h1, but this movement can also be achieved by using an axis other than the shaft 16. For example, as in the sewing machine shown in Patent Document 2, an axis other than the shaft 16 can be used as the rotation axis of the rotating part, and the first thread holding part h1 can be configured to rotate around the Z direction as the rotation axis, and the horizontal part t1 can be moved toward the needle hole 5a.

In addition, the sewing machine 1 of this embodiment is equipped with a so-called manual threading device in which the threading device is operated by the operator pressing down on the lever 7, but this is not limited to this. For example, instead of using the lever 7, the threading device may be operated by a motor.

1: Sewing machine 2: Sewing machine cover (cover)
2b: Face plate (second thread holding portion)
5: Needle 5a: Needle hole 6: Thread hook spring (second thread holding portion)
16: Shaft (rotating part)
17: Threading hook 20: Support body 24: Thread holding plate (first thread holding body)
h1: first thread holding portion h2: second thread holding portion t: upper thread t1: horizontal portion

Claims (4)

A sewing machine equipped with a threading device comprising a first thread holding portion and a threading hook which approach a needle hole provided at the tip of a needle from one side and the other side while descending toward the needle hole, the threading hook passes through the needle hole and captures an upper thread held by the first thread holding portion approaching the needle hole, thereby inserting the upper thread into the needle hole,
a second thread holding portion provided on a cover covering the threading device and holding the upper thread in a threading preparation stage;
the first thread holding portion does not hold the upper thread in the threading preparation stage, and holds the upper thread and releases the upper thread from the second thread holding portion while the threading device is moving downward;
the first thread holding portion includes a support body and a first thread holder that is displaceable between an open state in which the first thread holder is separated from the support body and a clamping state in which the first thread holder is close to the support body and can clamp the upper thread;
The sewing machine according to claim 1, wherein the first thread holder is displaced from the open state to the clamping state as the threading device descends . the first thread holding portion includes a threading arm that comes into contact with the upper thread as the threading device descends;
2. The sewing machine according to claim 1 , wherein the thread hooking arm and the first thread holder displaced to the clamping state cooperate to form a horizontal portion in the upper thread. The threading device includes a rotation unit that rotates the first thread holding unit,
3. The sewing machine according to claim 2 , wherein the horizontal portion is moved to a position facing the needle hole by lowering and rotating the first thread holding portion. The sewing machine according to any one of claims 1 to 3, characterized in that the holding force with which the second thread holding portion holds the upper thread is set to be weaker than the holding force with which the first thread holding portion holds the upper thread.

Images