Top dressing mechanism and sewing machine

Abstract

To propose a top stitching mechanism which does not require work of removing from a sewing machine, and which does not impair workability even in the case where a double chain stitch without using a decorative thread is performed, and to propose a sewing machine.SOLUTION: A top stitching mechanism 2 includes an expansion / storage mechanism which is provided at a sewing machine 1, and which can switch between an expanded state where a top stitching is executed by making a spreader 14 cooperate with needles 4, 5, 6, and a storage state where it is separated from the needles 4, 5, 6.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a top cover mechanism provided in a double chain stitch sewing machine, and to a sewing machine equipped with this top cover mechanism. [Background technology]

[0002] Sewing machines capable of performing double chain stitches as specified by symbols 406, 407, etc. in JIS-L0120 have been known for some time. By attaching a top decorative mechanism to this sewing machine, it is possible to perform double chain stitches with top decorative threads (hereinafter referred to as "top decorative stitches") as specified by symbols 602, 605, etc. (the stitch with symbol 605 is shown in Figure 7) in which decorative threads are added to stitches such as symbol 406. Note that the hatched threads in Figure 7 are decorative threads.

[0003] However, in a sewing machine capable of performing the above-mentioned two types of double chainstitches, if a top cover mechanism is installed when performing double chainstitching without using decorative thread, the top cover mechanism located near the needle gets in the way and reduces workability. For this reason, the top cover mechanism is removed when performing double chainstitching without using decorative thread, and the top cover mechanism is installed when performing top coverstitching. Patent Document 1 proposes providing a matching mark to facilitate alignment when attaching a spreader as a top cover mechanism to the drive arm of the sewing machine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-212286 A Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, although the sewing machine of Patent Document 1 can simplify the work of aligning the top covering mechanism, the worker must perform the work while visually checking the matching marks, and the work itself is not eliminated. In addition, there is a risk of problems such as losing the top covering mechanism after removing it from the sewing machine or accidentally damaging it during storage.

[0006] In view of these problems, the present invention aims to provide a top cover mechanism that does not need to be removed from the sewing machine and does not impair operability even when performing double chain stitching without using decorative thread, and a sewing machine equipped with this top cover mechanism. [Means for solving the problem]

[0007] The present invention is a top cover mechanism provided in a double chain stitch sewing machine, comprising a spreader and top cover thread guide of, By moving them together in the same direction, A deployed state in which the needle cooperates with the sewing machine to perform a top stitch, and a deployed state in which the needle cooperates with the sewing machine to perform a top stitch. The spreader and the top cover thread guide It is characterized by having a deployment and storage mechanism that can be switched between a separated storage state and a remote storage state.

[0008] In such a top decoration mechanism, it is preferable that the deployment and storage mechanism includes an axis supporting the spreader and the top decoration thread guide, and that the spreader and the top decoration thread guide can be switched between the deployed state and the stored state by sliding along the axis. It is preferable that such an upper cover mechanism includes a transmission mechanism that transmits power from a main shaft that drives the needle to the spreader in the deployed state and blocks the power in the stored state.

[0009] In addition, in such an upper cover mechanism, it is preferable that the transmission mechanism includes an alignment mechanism that aligns the operation of the needle and the operation of the spreader with a predetermined timing when switching from the stored state to the deployed state.

[0010] It is preferable that such an upper cover mechanism includes a guide mechanism that moves the spreader in a predetermined position and along a predetermined path when switching between the deployed state and the stored state.

[0011] It is also preferable to provide an upper cover thread guide that is switchable between an expanded state in which the upper cover thread is guided to the spreader to perform upper cover stitching, and a stored state in which the upper cover thread guide is separated from the needle, in conjunction with the deploying and storing mechanism.

[0012] The present invention also relates to a sewing machine including any one of the top covering mechanisms described above. Effect of the Invention

[0013] According to the top cover mechanism of the present invention, by switching the spreader to the deployed state by the above-mentioned deploying and storing mechanism, top cover stitching can be performed without removing the spreader from the sewing machine. In other words, there is no risk of losing or damaging the spreader, and the work of attaching and detaching the spreader is no longer necessary, improving workability. In addition, when the spreader is switched to the stored state by the deploying and storing mechanism, the spreader can be separated from the needle, making it possible to perform double chain stitching without using decorative thread with good workability. [Brief description of the drawings]

[0014] [Figure 1] 1 is a perspective view showing an embodiment of a sewing machine provided with a top covering mechanism according to the present invention; [Diagram 2] FIG. 2 is a perspective view of the upper decoration mechanism shown in FIG. [Diagram 3] FIG. 2 is an exploded view of the top decoration mechanism shown in FIG. [Figure 4] 2 is an explanatory diagram showing the deployed and stored states of an upper decoration guide in the upper decoration mechanism shown in FIG. 1. [Diagram 5] 2A to 2C are explanatory diagrams showing the deployed and stored states of the spreader in the upper covering mechanism shown in FIG. 1. [Figure 6] 2 is an explanatory diagram regarding the operation of the top decoration mechanism shown in FIG. 1. [Figure 7] FIG. 13 is an explanatory diagram of a top decorative stitch. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of a top cover mechanism according to the present invention and an embodiment of a sewing machine equipped with this top cover mechanism will be described with reference to the drawings. In the following description, for convenience, the directions of right, left, front, rear, top, bottom, and X, Y, and Z will be described in the drawings.

[0016] FIG. 1 shows a sewing machine 1 that embodies the sewing machine according to the present invention. The sewing machine 1 is equipped with an upper cover mechanism 2 that embodies the upper cover mechanism according to the present invention. The arm 1a of the sewing machine 1 is provided with a main shaft 3 that is rotated by a sewing machine motor (not shown), and the bed 1b is provided with a lower shaft that is rotated by the sewing machine motor (not shown). The main shaft 3 is connected to the upper cover mechanism 2 (equipped with a spreader 14 described later) and needles (consisting of three needles, a first needle 4, a second needle 5, and a third needle 6 in this embodiment), and the lower shaft is connected to a looper mechanism (not shown) and a feed mechanism (not shown) provided on the bed 1b. The sewing machine 1 is also equipped with a first needle thread T1, a second needle thread T2, a third needle thread T3, a decorative thread T4, and a looper thread T5 that are wound around thread spools. The sewing machine motor rotates and the elements connected to the main shaft 3 and the lower shaft work together to form stitches with the first needle thread T1, etc., and sew together the cloth. The sewing machine 1 of this embodiment is capable of performing the top decorative stitch shown in Fig. 7, and is also capable of performing double chain stitch without using the decorative thread T4. The sewing machine 1 is provided with members such as a needle thread guide 21 around the third needle 6, etc.

[0017] The partially enlarged view of Fig. 1 shows a deployed state in which the spreader 14 has moved close to the third needle 6, etc., and when the sewing machine motor rotates in this state, top top stitching can be performed. The overall perspective view of Fig. 1 shows a stored state in which the spreader 14 has moved upward and away from the third needle 6, etc., and when the sewing machine motor rotates in this state, double chain stitching can be performed without using the decorative thread T4. In the top top stitching mechanism 2 of this embodiment, the deployed state can be switched to the stored state by pushing down the deployment lever 17, which will be described later. Also, when the deployed state is in the deployed state, the storage lever 18 can be pushed from the front to the rear to switch to the storage state.

[0018] FIG. 2 shows the top cover mechanism 2 and the main shaft 3 in a stored state. The top cover cam 7 is attached to the main shaft 3 and rotates together with the top cover mechanism 2. The top cover mechanism 2 also includes a base plate 8, which is fixed to a sewing machine frame (not shown). The top cover mechanism 2 also includes a long cylindrical top cover shaft 9, a plate-shaped connecting plate 10, and a short cylindrical follower pin 11. The base plate 8 supports the top cover shaft 9 so that it can rotate. As shown in the figure, one end of the connecting plate 10 is connected to the top cover shaft 9, and the other end of the connecting plate 10 is connected to the follower pin 11. The top cover shaft 9 is biased in the direction of the arrow A (clockwise from the perspective of going from above to below) by a spring (not shown), and the follower pin 11 is always in contact with the top cover cam 7. Therefore, the main shaft 3 rotates in response to the top cover cam 7, and the top cover shaft 9 swings in response to the rotation of the main shaft 3.

[0019] Fig. 3 is an exploded view of the top covering mechanism 2. The top covering mechanism 2 of this embodiment further includes a mechanism core 12, an top covering thread guide 13, a spreader 14, an upper connector 15, a lower connector 16, a deployment lever 17, a storage lever 18, and a shoulder screw 19. Note that for convenience of illustration, some parts such as a cover 20 are omitted in Figs. 3, 4, and 5.

[0020] The mechanism core 12 is formed into a generally hollow shape, and is inserted into the upper decorative shaft 9 and supported thereon so as to be rotatable and axially slidable. The mechanism core 12 also has a slide portion 12a protruding from the outer circumferential surface.

[0021] The upper decorative thread guide 13 has a hole into which the upper decorative shaft 9 can be inserted and is provided with a pair of support parts 13a spaced apart in the vertical direction. The distance between the support parts 13a is approximately the same as the overall length of the mechanism core 12. The upper decorative thread guide 13 also has a plate-shaped release part receiver 13b extending from the left side to the right side, and a positioning part 13c provided at the upper end of the release part receiver 13b and protruding from the front to the rear.

[0022] The spreader 14 has a hole into which the upper decorative shaft 9 can be inserted and is provided with a pair of support parts 14a spaced apart in the vertical direction. The distance between the support parts 14a is approximately the same as the length from the top surface of the upper support part 13a to the bottom surface of the lower support part 13a. The spreader 14 also has a spreader retraction cam follower 14b that protrudes from left to right.

[0023] The upper connector 15 has a short cylindrical shape, and its upper end is connected to the spreader 14 while being oriented in the vertical direction. In other words, the upper connector 15 operates integrally with the spreader 14. The lower end of the upper connector 15 is formed into a semi-spherical shape.

[0024] The lower connector 16 has a connection hole 16a that is connected to the lower end of the upper decoration shaft 9. The lower connector 16 and the upper decoration shaft 9 are attached with a predetermined angular relationship, so the rotation angle of the upper decoration cam 7 and the swing angle of the lower connector 16 are uniquely determined. The lower connector 16 also has a groove-shaped spreader angle setting cam portion 16b extending in the vertical direction on the radially outer side of the connection hole 16a. The groove width of the spreader angle setting cam portion 16b is approximately the same as the outer diameter of the upper connector 15. Above the spreader angle setting cam portion 16b, a pair of inclined portions 16c are provided that are inclined so that the distance between them becomes wider as they go from the bottom to the top.

[0025] The deployment lever 17 is formed in a roughly L-shape, and a plate-like portion 17a extending in the vertical direction is provided with a slide portion fixing hole 17b and a stepped screw slide portion 17c located below the slide portion fixing hole 17b. The plate-like portion 17a is also provided with a cylindrical rotation pin 17d that protrudes toward the right.

[0026] The storage lever 18 is provided with a pin hole 18a located in the center in the longitudinal direction and into which the rotation pin 17d can be inserted. The storage lever 18 is provided at its upper end with a positioning release portion 18b that protrudes from the rear toward the front.

[0027] The upper cover mechanism 2 includes springs (not shown) which respectively bias the upper cover thread guide 13, the spreader 14, the deploying lever 17, and the storing lever 18. The upper cover thread guide 13 is biased in the direction of arrow B (clockwise when viewed from above toward below), the spreader 14 is biased in the direction of arrow C (counterclockwise when viewed from above toward below), the deploying lever 17 is biased in the direction of arrow D (direction from below toward above), and the storing lever 18 is biased in the direction of arrow E (counterclockwise when viewed from right to left).

[0028] Here, the above-mentioned base plate 8 will be described. The base plate 8 of this embodiment has a pair of support parts 8a that have a hole into which the upper cover shaft 9 can be inserted and are spaced apart in the vertical direction. A slide groove 8c that passes through the plate-shaped part 8b located on the right side of the base plate 8 and extends in the vertical direction is provided. A spreader slide groove 8d that extends in the vertical direction is provided in the plate-shaped part 8b in front of the slide groove 8c. A spreader retraction cam part 8e that is inclined from the front to the rear as it goes from the top to the bottom is provided below the spreader slide groove 8d. An upper cover thread guide slide cam part 8f that extends in the vertical direction is provided at the front end of the plate-shaped part 8b. A stopper 8g that protrudes from the rear to the front is provided above the upper cover thread guide slide cam part 8f, and a positioning groove 8h that is formed by cutting the plate-shaped part 8b from the front to the rear is provided below the upper cover thread guide slide cam part 8f.

[0029] These members constituting the top decoration mechanism 2 can be assembled, for example, in the following procedure. First, the rotating pin 17d is inserted into the pin hole 18a to rotatably support the storage lever 18 relative to the deployment lever 17. The storage lever 18 is held in place by a retaining means (not shown) (for example, a fine groove is provided at the tip of the rotating pin 17d, and an E-ring is fitted in after the pin hole 18a is inserted). Then, the stepped screw 19 inserted into the stepped screw slide portion 17c is screwed into the base plate 8. The deployment lever 17 is thus supported so as to be movable up and down relative to the base plate 8.

[0030] In addition, when attaching the mechanism core 12, the upper decoration thread guide 13, and the spreader 14 to the base plate 8, the mechanism core 12 is sandwiched between the pair of supports 13a, and the pair of supports 13a is sandwiched between the pair of supports 14a, and then the upper decoration shaft 9, which has been inserted into one of the supports 8a of the base plate 8, is inserted into the support parts 14a, etc. When assembling the mechanism core 12, etc. to the base plate 8, the slide part 12a is inserted into the slide part fixing hole 17b by passing through the slide groove 8c. Then, the lower end of the upper decoration shaft 9 is inserted into the connecting hole 16a of the lower connector 16, and the lower connector 16 is attached to the upper decoration shaft 9.

[0031] In this assembled state, the mechanism core 12, the top cover thread guide 13, the spreader 14, the deployment lever 17, and the storage lever 18 are supported so as to move integrally in the vertical direction with respect to the base plate 8 and the top cover shaft 9. As described above, the deployment lever 17 is biased in the direction of the arrow D, so that the mechanism core 12, the top cover thread guide 13, the spreader 14, the deployment lever 17, and the storage lever 18 are positioned in the vertical direction as the positioning portion 13c presses against the lower end of the stopper 8g. The decorative thread guide 13 is biased in the direction of the arrow B, so that the positioning portion 13c presses against the top cover thread guide slide cam portion 8f, so that the spreader 14 is positioned in the circumferential direction. And the spreader 14 is biased in the direction of the arrow C, so that the spreader retraction cam follower 14b is inserted into the spreader slide groove 8d, so that the spreader retraction cam follower 14b is positioned in the circumferential direction. Here, a biasing force acts on the storage lever 18 in the direction of the arrow E, but since the storage lever 18 is covered with the cover 20 shown in Fig. 2, even in the biased state, it does not rotate excessively in the direction of the arrow E. Incidentally, the upper connecting body 15 is inserted into the spreader angle determining cam portion 16b of the lower connecting body 16 as described later, but is located above the lower connecting body 16 when the positioning portion 13c is pressed against the lower end of the stopper 8g.

[0032] Next, the stored state and the deployed state of the upper decoration mechanism 2 in this embodiment will be described. First, the stored state and the deployed state of the upper decoration thread guide 13 will be described with reference to Fig. 4. Note that Fig. 4 only partially shows the base plate 8 and the deployment lever 17. Fig. 4(a) shows the stored state, and Fig. 4(b) shows the deployed state.

[0033] In the stored state as shown in Fig. 4(a), the deploying lever 17 is biased in the direction of the arrow D. Therefore, the top cover thread guide 13, which moves vertically together with the deploying lever 17, is also biased in the direction of the arrow D. Therefore, the top cover thread guide 13 is stopped in the vertical direction with the positioning portion 13c pressing against the lower end of the stopper 8g. In addition, since the top cover thread guide 13 is biased in the direction of the arrow B, the positioning portion 13c is pressed against the top cover thread guide slide cam portion 8f.

[0034] When the deploying lever 17 is pressed down, the top cover thread guide 13, which moves up and down in conjunction with the deploying lever 17, moves downward with the positioning portion 13c pressed against the top cover thread guide slide cam portion 8f. When the positioning portion 13c reaches the positioning groove 8h, the positioning portion 13c fits into the positioning groove 8h by the biasing force in the direction of arrow B. In other words, since the top cover thread guide 13 is positioned in the up and down direction by the positioning portion 13c and the positioning groove 8h, even if the deploying lever 17 is released, the top cover thread guide 13 and the deploying lever 17 are maintained in the state in which they have moved downward (deployed state).

[0035] In this way, when the deployment lever 17 is pressed down to switch the upper covering thread guide 13 from the stored state to the deployed state, the upper covering thread guide 13 descends while maintaining an angle about the upper covering shaft 9, and rotates in the direction of arrow B when the positioning portion 13c fits into the positioning groove 8h. That is, as shown in the partially enlarged view of Fig. 1, the upper covering thread guide 13 is located in the vicinity of the third needle 6, etc. in the deployed state, but in the process of switching from the stored state to the deployed state, it descends while maintaining an angle rotated in a direction away from the third needle 6, etc., and therefore it is possible to avoid collision with the third needle 6, etc. and the needle thread guide 21, etc. provided in the vicinity thereof.

[0036] On the other hand, when switching from the deployed state to the stored state, the lower end of the storage lever 18 is pressed from the front to the rear as shown in Fig. 4(b). This action rotates the storage lever 18 in the opposite direction to the arrow E, and the positioning release portion 18b presses against the release portion receiver 13b of the top cover thread guide 13. This causes the top cover thread guide 13 to rotate in the opposite direction to the arrow B, and the engagement between the positioning portion 13c and the positioning groove 8h is released. Thereafter, the top cover thread guide 13 moves upward with the positioning portion 13c pressed against the top cover thread guide slide cam portion 8f by the biasing forces in the directions of the arrows B and D, and stops when the positioning portion 13c presses against the lower end of the stopper 8g.

[0037] When switching from the deployed state to the stored state in this manner, the upper decorative thread guide 13 rises after rotating in the opposite direction to the arrow B. That is, as shown in the partially enlarged view of Fig. 1, the upper decorative thread guide 13 in the deployed state located near the third needle 6 etc. moves away from the third needle 6 etc., and then rises while maintaining that angle, thereby making it possible to avoid collision with the third needle 6 etc. and the needle thread guide 21 etc. provided in the vicinity thereof.

[0038] Next, the stored state and deployed state of the spreader 14 will be described with reference to Fig. 5. Note that Fig. 5 only shows a portion of the base plate 8 and the deployment lever 17. Fig. 5(a) shows the stored state, and Fig. 5(b) shows the deployed state.

[0039] As described above, the spreader 14 moves vertically together with the deployment lever 17 and the like. In the stored state shown in FIG. 4(a), the deployment lever 17 and the like are stopped in a state in which the positioning portion 13c is pressed against the lower end of the stopper 8g by the biasing force in the direction of the arrow D. Therefore, the spreader 14 is also stopped in the vertical direction in the stored state shown in FIG. 5(a). In addition, in the stored state, the spreader retraction cam follower 14b is inserted into the spreader slide groove 8d, so the movement of the spreader 14 in the rotational direction is restricted. Note that, as described above, the spreader 14 is subjected to a biasing force in the direction of the arrow C, so the spreader retraction cam follower 14b is pressed against the front wall surface of the spreader slide groove 8d.

[0040] When the deployment lever 17 is pushed down, the spreader 14 moves downward in conjunction with the deployment lever 17 with the spreader retraction cam follower 14b inserted into the spreader slide groove 8d. An inclined spreader retraction cam portion 8e is provided below the spreader slide groove 8d, and the width of the groove increases from front to rear as it moves from top to bottom. That is, in the stored state shown in Fig. 5(a), the rotational movement of the spreader 14 is restricted, but in the deployed state shown in Fig. 5(b), the restriction on the rotational movement of the spreader 14 is released.

[0041] Incidentally, since the upper connector 15 is connected to the spreader 14, when the spreader 14 descends, the upper connector 15 also descends. Here, the lower connector 16 connected to the upper decorative shaft 9 is located below the upper connector 15. Therefore, when the spreader 14 descends, the upper connector 15 is inserted into the lower connector 16, and the lower end of the upper connector 15 fits into the spreader angle setting cam portion 16b. In this embodiment, the groove width of the spreader angle setting cam portion 16b and the outer diameter of the upper connector 15 are approximately the same, so that the upper connector 15 fits into the spreader angle setting cam portion 16b, and the spreader 14 swings integrally with the lower connector 16.

[0042] In addition, the upper cover shaft 9 to which the lower connector 16 is connected is always oscillating when the main shaft 3 is rotating, because the follower pin 11 is in contact with the upper cover cam 7 as shown in FIG. 2. For this reason, when the spreader 14 descends, the spreader angle determining cam portion 16b of the lower connector 16 may not be located directly below the upper connector 15. On the other hand, the lower connector 16 of this embodiment has a pair of inclined portions 16c above the spreader angle determining cam portion 16b that are inclined so that the distance between them becomes wider from the bottom to the top, so that when the descended upper connector 15 comes into contact with the inclined portions 16c, the spreader 14 rotates according to the inclined portions 16c, and the upper connector 15 moves toward the spreader angle determining cam portion 16b. In other words, the inclined portion 16c eliminates the angular misalignment between the spreader 14 and the lower connector 16, so that when the spreader 14 descends, the upper connector 15 can be smoothly fitted into the spreader angle setting cam portion 16b.

[0043] In this way, when the deployment lever 17 is pressed down to switch the spreader 14 from the stored state to the deployed state, the spreader 14 descends while maintaining an angle about the upper covering shaft 9, and rotates a predetermined angle at the point where the upper connector 15 and the lower connector 16 fit together. That is, as shown in the partially enlarged view of Fig. 1, the spreader 14 is located near the third needle 6 etc. in the deployed state, but in the process of switching from the stored state to the deployed state, the spreader descends while maintaining an angle rotated in a direction away from the third needle 6 etc., and therefore it is possible to avoid collision with the third needle 6 etc. and the needle thread guide 21 etc. provided in the vicinity thereof.

[0044] When the storage lever 18 is pressed to switch from the deployed state to the stored state as shown in FIG. 4(b), the spreader 14 rises due to the biasing force in the direction of the arrow D (see FIG. 5(b)), and the engagement between the upper connector 15 and the lower connector 16 is released. When the engagement between the upper connector 15 and the lower connector 16 is released, the spreader 14 rotates due to the biasing force in the direction of the arrow C until the spreader retraction cam follower 14b presses against the front wall surface of the spreader slide groove 8d. Note that even if the spreader 14 rises before the rotation is completed, the spreader retraction cam follower 14b comes into contact with the spreader retraction cam portion 8e and the spreader 14 rotates in the direction of the arrow C, so that it is possible to avoid collision with the third needle 6, etc. and the needle thread guide 21 provided around it, etc. Thereafter, the spreader 14 rises while maintaining that angle in a state in which the spreader retraction cam follower 14b is inserted into the spreader slide groove 8d, and switches to the stored state.

[0045] In this way, when switching from the deployed state to the stored state, the spreader 14 rotates in a direction away from the third needle 6, etc., and rises while maintaining that angle, thereby avoiding collision with the third needle 6, etc., or components installed around it.

[0046] When the top cover mechanism 2 is switched to the stored state, the top cover thread guide 13 and the spreader 14 move upward away from the third needle 6 and the like. In the stored state, the upper connector 15 is separated from the lower connector 16, so that the spreader 14 does not swing even when the main shaft 3 rotates. This allows the double chain stitching without using the decorative thread T4 to be performed with good workability. When the top cover mechanism 2 is switched to the deployed state, the top cover thread guide 13 and the spreader 14 move down to the vicinity of the third needle 6 and the like, and the upper connector 15 engages with the spreader angle determining cam portion 16b, so that the spreader 14 swings in synchronization with the rotation of the main shaft 3, allowing the top cover stitching shown in FIG. 7 to be performed. Here, the process of forming the top cover stitching shown in FIG. 7 will be described with reference to FIG. 6.

[0047] In FIG. 6, the first needle thread T1, the second needle thread T2, and the third needle thread T3 are respectively passed through the first needle 4, the second needle 5, and the third needle 6, the looper thread T5 is passed through a looper (not shown), and the decorative thread T4 is passed through the hole-shaped portion at the tip of the upper decorative thread guide 13. 6 shows a state in which the first needle 4, the second needle 5, and the third needle 6 have been moved to their uppermost positions, and the spreader 14 has been moved to its leftmost position. In this state, the tip of the spreader 14 captures the decorative yarn T4 and holds the captured decorative yarn T4 so as to cross the first needle 4, etc.

[0048] Thereafter, as the first needle 4 and the like descend as shown in the upper drawing of Figure 6, the third needle 6 passes behind the decorative thread T4. At this time, the spreader 14, which moves to the right, releases its hold on the decorative thread T4.

[0049] 6, the first needle 4 etc. move to the lowest position and cooperate with the looper mechanism and feed mechanism (not shown) to form a top decorative stitch while sewing in the decorative thread T4 with the first needle thread T1 etc. and the looper thread T5. At this time, the spreader 14 passes through the decorative thread T4 held by the top decorative thread guide 13 and moves to the rightmost position, to the lower right of the hole-shaped portion at the tip of the top decorative thread guide 13.

[0050] Thereafter, as shown in the lower drawing in Fig. 6, the first needle 4 etc. rises, and the spreader 14 moves to the left while capturing the decorative thread T4. Then, after the cloth is fed out by the feed mechanism, the first needle 4 etc. and the spreader 14 move to the position shown in the left drawing in Fig. 6. Thereafter, the above-mentioned process is repeated to perform the top decorative stitch shown in Fig. 7.

[0051] Although the embodiments embodying the present invention have been illustrated above, the present invention is not limited to the specific embodiments, and various modifications and changes 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 embodiments 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.

[0052] For example, in the upper decoration mechanism 2 of this embodiment, the "deployment and storage mechanism" in this specification is embodied as a configuration mainly consisting of the sliding structure of the spreader 14 by the upper decoration shaft 9 and the support part 14a of the spreader 14, and the upper decoration thread guide 13 is switched between the deployed state and the stored state in conjunction with the spreader 14 by the sliding structure of the support part 13a of the upper decoration thread guide 13 and the upper decoration shaft 9 and the structure in which the support part 14a sandwiches the support part 13a, but is not limited to the above embodiment, and another configuration may be added or replaced with an alternative configuration. For example, instead of a mechanism that slides up and down to switch between the deployed state and the stored state, the spreader 14 and the upper decoration thread guide 13 may be switched between the deployed state and the stored state by a mechanism that swings back and forth. Alternatively, the spreader 14 may be configured to slide up and down to switch between the deployed state and the stored state, and the upper decoration thread guide 13 may be configured to swing back and forth to switch between the deployed state and the stored state without being linked to each other. In addition, the "transmission mechanism" in this specification is embodied by the spreader angle determining cam portion 16b of the upper connecting body 15 and the lower connecting body 16, but is not limited thereto. For example, a member that moves up and down together with the deployment lever 17 may be provided, and when the deployment lever 17 rises, this member is interposed between the upper cover cam 7 and the follower pin 11 to separate the follower pin 11 from the upper cover cam 7, thereby switching the transmission of power from the main shaft 3. Also, a clutch may be provided between the upper cover shaft 9 and the lower connecting body 16, and when the clutch is activated, the lower connecting body 16 is oscillated by the power from the main shaft 3, and when the clutch is deactivated, the lower connecting body 16 is stopped. Also, two motors, one for moving the first needle 4 up and down and one for oscillating the spreader 14, may be provided, and the two motors may be driven in the deployment state, while the motor for oscillating the spreader 14 is stopped in the storage state.

[0053] In this embodiment, the outer diameter of the upper connecting body 15 and the groove width of the spreader angle setting cam portion 16b are approximately the same, and the upper connecting body 15, the spreader angle setting cam portion 16b, and the inclined portion 16c are configured to function as the "alignment mechanism" in this specification, but for example, the groove width of the spreader angle setting cam portion 16b may be made wider than the outer diameter of the upper connecting body 15 to function as the "transmission mechanism" and the "alignment mechanism" may be provided separately. The "alignment mechanism" may also be configured to include two motors, one for moving the first needle 4 etc. up and down and one for swinging the spreader 14, each of which is provided with an encoder for measuring the rotation angle, and the rotation angle of each motor is measured by the encoder to synchronize the two, thereby aligning the operation of the first needle 4 etc. and the operation of the spreader 14 to a predetermined timing.

[0054] In this embodiment, the "guide mechanism" in this specification is embodied by the spreader retraction cam follower 14b provided in the spreader 14, the spreader slide groove 8d provided in the base plate 8, and a spring that urges the spreader 14 in the direction of the arrow C, or the spreader retraction cam portion 8e, but is not limited to the above-mentioned embodiment, and for example, something equivalent to the spreader slide groove 8d or the spreader retraction cam portion 8e may be provided in the spreader 14, and something equivalent to the spreader retraction cam follower 14b may be provided in the base plate 8. Note that in this embodiment, in order to ensure the operation of the spreader 14, both the spring that urges the spreader 14 in the direction of the arrow C and the spreader retraction cam portion 8e are provided. However, if at least one of a spring that biases the spreader 14 in the direction of arrow C or a spreader retraction cam portion 8e is provided, the spreader 14 can be rotated in the direction of arrow C after the engagement between the upper connecting body 15 and the lower connecting body 16 is released.

[0055] In addition, although the top covering mechanism 2 in the present embodiment is stored inside the cover of the sewing machine 1 in the stored state, it may be stored outside the cover. For example, the front outer side of the arm portion 1a is not a place that impairs workability for the worker, and is not a place that is visually obstructive, so the top covering mechanism 2 may be configured to be stored in such a place. [Explanation of symbols]

[0056] 1: Sewing machine 2: Top decoration mechanism 3: Main shaft 4: First stitch 5:Second needle 6:Third needle 8: Base plate 8c: Slide groove 8d: Spreader slide groove 8e: Spreader retraction cam part 8f: Upper cover thread guide slide cam part 8g: Stopper 8h: Positioning groove 9: Top decoration scroll 10: Connecting plate 11: Follower pin 12: Mechanism core 12a: Slide section 13: Top cover thread guide 13a: Support part 13b: Release part receiver 13c: Positioning section 14: Spreader 14a: Support part 14b: Spreader retraction cam follower 15: Upper connection body 16:Lower connection body 16b: Spreader angle setting cam part 16c: Inclined part 17: Deployment lever 17b: Slide fixing hole 17c: Step screw slide 17d: Rotating pin 18: Storage lever 19: Shoulder screw

Claims

1. A top cover mechanism provided in a double chain stitch sewing machine, The top cover mechanism is provided with a deployment and storage mechanism that can switch between an deployed state in which the spreader and the top cover thread guide are moved integrally in the same direction to perform top cover stitching in cooperation with a needle, and a stored state in which the spreader and the top cover thread guide are separated from the needle.

2. The deployment and storage mechanism includes a shaft supporting the spreader and the upper decoration thread guide, The top cover mechanism according to claim 1 , wherein the spreader and the top cover thread guide are switched between the deployed state and the stored state by sliding on the shaft.

3. 3. The top cover mechanism according to claim 1, further comprising a transmission mechanism for transmitting power from a main shaft for driving the needle to the spreader in the deployed state and cutting it off in the stored state.

4. The top cover mechanism according to claim 3 , wherein the transmission mechanism includes an alignment mechanism that aligns the operation of the needle and the operation of the spreader with a predetermined timing when switching from the stored state to the deployed state.

5. The top cover mechanism according to any one of claims 1 to 4, further comprising a guide mechanism for moving the spreader in a predetermined position and along a predetermined path when switching between the deployed state and the stored state.

6. A sewing machine comprising the top covering mechanism according to any one of claims 1 to 5.

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