Material feeder in sewing machine

Abstract

The present invention addresses the problem of efficiently switching, changing or selecting a string-like material to be used for sewing. A material feeder (1) comprises: a bobbin placement device (2) for rotatably supporting each of a plurality of bobbins (21) around which a string-like material is wound, the bobbin placement device (2) corresponding to one sewing head; and a rotation drive device (3) for selectively imparting rotational motion to any of the bobbins (21). The selected bobbin (21) is rotated by the rotation drive device (3) to positively deliver the string-like material used for sewing from the bobbin (21). The rotary drive device (3) may include one rotary drive source (31) and a transmission mechanism (32) for selectively transmitting rotary motion based on the rotary drive source to any of the bobbins. This contributes to simplification, compactification, and cost reduction of the configuration. The transmission mechanism (32) may include a switching mechanism (33) that switches the transmission path of the rotational motion in order to selectively transmit the rotational motion based on the rotational drive source (31) to any of the bobbins.

Description

Material feeding device in a sewing machine

[0001] The present invention relates to a sewing machine that sews string-like materials such as tapes and cords onto a workpiece by lockstitch, and more particularly to a material supply device for supplying string-like materials to be sewn in a sewing machine.

[0002] Conventionally, there is a type of sewing machine known that includes a needle bar that is driven up and down, a sewing needle attached to the lower end of the needle bar, a rotating body assembled coaxially with the needle bar and freely rotating around its axis, a guide device attached to the rotating body that guides a string-like material (for example, a string-like embroidery material such as tape or cord) to the needle base position of the sewing needle, and a material supply device that supplies the string-like material to the guide device. The rotating body is rotated according to the direction of movement of the fabric based on embroidery data, and the orientation of the guide device is changed so that the direction of guidance of the string-like material to the needle base is appropriate, while sewing the string-like material to the workpiece (fabric) by lockstitch, or further, a zigzag mechanism is used to zigzag the guide device and sew the string-like material to the workpiece by zigzag stitch. As a material supply device for this type of sewing machine, a configuration is adopted that uses a large bobbin on which the string-like material is wound, in order to accommodate the use of large quantities of string-like material. In this case, the bobbin is actively rotated to ensure smooth unwinding of the string-like material from the bobbin (for example, Patent Document 1 or 2).

[0003] As shown in Patent Document 1 or 2, a material supply device using this type of rotation-driven large bobbin has a configuration in which one large bobbin is arranged corresponding to one sewing head, and a driving device for rotationally driving the bobbin is installed corresponding to the bobbin. Therefore, when replacing the bobbin to change the type of string-like material to be sewn, not only the bobbin replacement work but also the work of replacing the string-like material (removing the previous material and attaching the next material) in the guiding path of the string-like material from the bobbin to the guiding device must be performed, which has the problem of taking a lot of work. In addition, since such bobbin replacement work must be performed by temporarily stopping the sewing operation of the sewing machine, it is not suitable for automated work such as automatically changing the type of string-like material and continuing sewing while continuing the continuous sewing operation, and there is also a problem of poor production efficiency.

[0004] Japanese Patent Application Laid-Open No. 2005-144056, Japanese Patent Application Laid-Open No. 2007-159829

[0005] The present invention has been made in view of the above points, and an object thereof is to provide a material supply device that can efficiently perform switching, changing, or selecting of a string-like material to be sewn in a sewing machine.

[0006] A material supply device in a sewing machine according to the present invention is a material supply device for supplying a string-like material to be sewn in a sewing machine, and includes a bobbin arrangement device that rotatably supports a plurality of bobbins wound with the string-like material corresponding to one sewing head, and a rotation driving device that selectively imparts a rotational movement to any one of the bobbins, and is characterized in that the string-like material fed out from the selected bobbin is supplied to the corresponding sewing head as the bobbin rotates.

[0007] According to the present invention, a rotational drive device selectively applies rotational motion to one of a plurality of bobbins arranged in a bobbin placement device, and the string-like material unwound from the selected bobbin is supplied to the sewing head as the bobbin rotates. This provides the excellent effect of easily and efficiently changing or switching the string-like material to be sewn. In particular, even when the weight of the bobbin wound with the string-like material is heavy, the string-like material can be smoothly unwound from the bobbin. Therefore, in a material supply device suitable for using large bobbins, this provides the excellent effect of easily and efficiently changing or switching the string-like material to be sewn.

[0008] In one embodiment, the rotary drive device may include one rotary drive source and a transmission mechanism that selectively transmits the rotational motion based on the rotary drive source to any of the bobbins. This reduces the number of rotary drive sources that the rotary drive device must have, contributing to a simpler and more compact configuration, and also reducing manufacturing costs. In a further embodiment, the transmission mechanism may include a switching mechanism that switches the transmission path of the rotational motion in order to selectively transmit the rotational motion based on the rotary drive source to any of the bobbins.

[0009] There can be various variations in how the multiple bobbins are arranged in the bobbin arrangement device. The switching mechanism can be implemented in relation to how the multiple bobbins are arranged in the bobbin arrangement device. For example, the transmission mechanism may include an operating end for transmitting rotational motion based on the rotational drive source to the bobbins, and the switching mechanism may switch the transmission path of the rotational motion by displacing the operating end in an arc or curved shape. In another example, the transmission mechanism may include an operating end for transmitting rotational motion based on the rotational drive source to the bobbins, and the switching mechanism may switch the transmission path of the rotational motion by displacing the operating end linearly. The arrangement of the bobbins in the bobbin arrangement device may involve arranging the multiple bobbins in an arc or curved shape, or arranging the multiple bobbins in series.

[0010] A perspective view of a material supply device according to one embodiment of the present invention (first embodiment), viewed from the front. A perspective view of the material supply device according to the same embodiment, viewed from the rear. A right side view of the material supply device according to the same embodiment. A rear view of the material supply device according to the same embodiment. A view from the rear to illustrate the selective bobbin switching operation in the same embodiment. A view from the rear of a modified example of the first embodiment. A perspective view of a material supply device according to another embodiment of the present invention (second embodiment), viewed from the front. A front view of the material supply device according to the embodiment shown in Figure 7.

[0011] Figure 1 is a perspective view of the material supply device 1 according to one embodiment (first embodiment) as seen from the front, and Figure 2 is a perspective view of the material supply device 1 as seen from the rear. Figure 3 is a right side view of the material supply device 1, and Figure 4 is a rear view of the material supply device according to the same embodiment. Note that Figure 1 shows the rear side covered with a cover 5, but Figures 2 and onward show the rear side with the cover 5 removed. This material supply device 1 is installed above one sewing head (not shown) of a sewing machine, such as a lockstitch handle embroidery machine, and functions to supply string-like material to be sewn by the sewing machine to the sewing head.

[0012] The material supply device 1 includes a bobbin placement device 2 that rotatably supports a plurality of bobbins 21 wound with string-like material L, and a rotation drive device 3 that selectively imparts rotational motion to any of the bobbins 21. The figure shows an example in which three bobbins 21, each wound with a different string-like material L, are placed in the bobbin placement device 2, and the string-like material L drawn from each bobbin 21 is supplied to the sewing head below. As one bobbin 21 is rotated by the rotation drive device 3, the string-like material L is actively fed out from that bobbin 21 and supplied to the sewing head.

[0013] The bobbin placement device 2 includes a support plate (support section) 22 on which a plurality of bobbins 21 are placed, and a plurality of rotating bodies 23 that are individually connected to each bobbin 21 placed on the support plate 22, enabling the connected bobbins 21 to rotate as a whole. On the support plate 22, a rotating body 23 is rotatably held at each portion where each bobbin 21 is detachably installed. A pair of mounting members 4 are mounted upright on the sewing machine frame (not shown) in the direction directly above, and the support plate 22 is installed on the mounting members 4 with its front surface inclined at an appropriate angle so as to point diagonally upward.

[0014] One rotating body 23 includes a rotating plate 23a positioned on the rear side of the support plate 22, and a bobbin shaft 23b attached to the center of the rotating plate 23a, which rotatably penetrates the support plate 22 and protrudes to the front side. A stopper 23c is detachably attached to the tip of the protruding bobbin shaft 23b. The detachable mounting structure of the stopper 23c to the bobbin shaft 23b may be any structure such as fitting, screwing, or bolting. With the stopper 23c removed, the bobbin 21 can be attached to and detached from the bobbin shaft 23b from the tip side (from the front side of the support plate 22).

[0015] As shown in Figure 3 (side view), a stopper plate 23d is provided on the front side of the support plate 22, near the base of the bobbin shaft 23b, and the stopper plate 23d is rotatable together with the bobbin shaft 23b. As is known, the bobbin 21 has flanges 21a and 21b at both ends. When the bobbin 21 is mounted on the bobbin shaft 23b, the flange 21b closer to the front side of the support plate 22 abuts against the stopper plate 23d, and the flange 21a on the opposite side abuts against the stopper 23c attached to the bobbin shaft 23b, and the bobbin 21 is sandwiched between the two stoppers 23c and 23d, so that the bobbin 21 can rotate together with the bobbin shaft 23b.

[0016] As can be seen from Figure 3, the bobbin shaft 23b is upright with respect to the plane (front) of the support plate 22, so the axis of the bobbin 21 inserted into the bobbin shaft 23b is directed diagonally upward at an appropriate angle, corresponding to the inclination of the plane (front) of the support plate 22. This configuration, in which the axis of the bobbin 21 placed in the bobbin placement device 2 is directed diagonally upward at an appropriate angle, makes it easier for the operator to attach and detach the bobbin 21 from the tip (open end) side of the bobbin shaft 23b, improving operability during bobbin attachment and detachment work. Furthermore, if the axis of the bobbin 21 were directed vertically upward, the string-like material L wound on the bobbin 21 would easily unwind downward due to gravity. In contrast, the configuration in which the axis of the bobbin 21 is directed diagonally upward, as in this embodiment, has the advantage that the string-like material L is less likely to unwind due to gravity. Furthermore, the inclination of the flat surface (front) of the support plate 22 allows the actual area of ​​the flat surface (front) of the support plate 22 to be larger than the small area it occupies when viewed from directly above, which has the advantage of allowing more bobbins 21 to be placed on the support plate 22.

[0017] Referring to Figures 2 to 4, the rotary drive device 3 provided on the back side of the support plate 22 includes one rotary drive source (e.g., an electric motor) 31 and a transmission mechanism 32 that selectively transmits the rotational motion based on the rotary drive source 31 to one of the bobbins 21. The rotary drive source 31 is fixed to the back surface of the support plate 22 via a bracket 41. The transmission mechanism 32 broadly includes a mechanism for transmitting the rotational motion based on the rotary drive source 31 and a switching mechanism 33 for switching the transmission path of the rotational motion.

[0018] The mechanism for transmitting rotational motion based on the rotational drive source 31 will be described as follows: A drive pulley 32a is connected to the rotational output shaft 31a of the rotational drive source 31, and the rotation of the drive pulley 32a is transmitted to a driven pulley 32c via a transmission belt 32b. A drive roller 32d is attached to the rotational shaft of the driven pulley 32c, and the rotation of the drive roller 32d is configured to be transmitted to the rotating plate 23a of the rotating body 23. More specifically, an O-ring 23e made of a friction material such as rubber is fitted around the circumference of the rotating plate 23a, and as will be described later, the drive roller 32d is in close contact with the O-ring 23e of the rotating plate 23a of the rotating body 23 corresponding to one selected bobbin 21. As a result, the rotation of the driven pulley 32c is transmitted via the drive roller 32d to the O-ring 23e which is in close contact with the drive roller 32d, and the rotating plate 23a rotates together with the O-ring 23e, causing the rotating body 23 to rotate. In this way, the rotational motion based on the rotational drive source 31 is transmitted to the bobbin 21 via the rotating body 23. The drive roller 32d functions as the working end (or far end) for transmitting the rotational motion based on the rotational drive source 31 to the bobbin 21.

[0019] The switching mechanism 33 includes a swing arm 33a and an air cylinder 33b for switching the tilt angle of the swing arm 33a. The swing arm 33a has a pivot point at one end (lower end), and the other end (upper end) can swing in an arc shape around this pivot point. A link pin 33c is provided in the middle of the swing arm 33a, and the tip of the linear rod 33d of the air cylinder 33b is pivotally connected to this link pin 33c. A bearing portion is provided at the upper end of the swing arm 33a that pivotally supports the rotation axis of the driven pulley 32c and the drive roller 32d. The linear rod 33d extends and retracts in accordance with the extension and retraction control of the air cylinder 33b, tilting the swing arm 33a via the link pin 33c, and the tilt angle of the swing arm 33a is set (switched). In accordance with the inclination of the swing arm 33a, the drive roller 32d, which is supported on its upper end, is displaced in an arc shape (or curved shape).

[0020] In this embodiment, the three bobbins 21 are arranged on the support plate 22 at an angle forming a triangle (or in an arc or curve). The air cylinder 33b is of a type that can switch the linear position of the linear rod 33d to three positions. For convenience, these three positions will be called the right position, the center position, and the left position. Figures 2 to 4 show the state in which the linear rod 33d is set to the center position. In this state, the drive roller 32d is in close contact with the rotating plate 23a (O-ring 23e) of the centrally located bobbin 21, and the rotation of the drive roller 32d is selectively transmitted to the central bobbin 21. As shown in Figure 5(a), when the air cylinder 33b is extended and the linear drive rod 33d is set to the left position, the drive roller 32d comes into close contact with the rotating plate 23a (O-ring 23e) of the bobbin 21 located on the left side when viewed from the rear, and the rotation of the drive roller 32d is selectively transmitted to the left bobbin 21. As shown in Figure 5(b), when the air cylinder 33b is retracted and the linear drive rod 33d is set to the right position, the drive roller 32d comes into close contact with the rotating plate 23a (O-ring 23e) of the bobbin 21 located on the right side when viewed from the rear, and the rotation of the drive roller 32d is selectively transmitted to the right bobbin 21. In this way, the transmission path of rotational motion based on the rotational drive source 31 is switched by the switching mechanism 33, and one of the bobbins 21 is selectively rotated. In other words, in this example, the switching mechanism 33 switches the transmission path of the rotational motion by displacing the drive roller 32d (i.e., the working end) in an arc (or curved shape).

[0021] A control device (not shown) for controlling the rotary drive source 31 and the air cylinder 33b is provided attached to the sewing machine. This control device selects one bobbin 21 on which the string-like material to be sewn by the sewing head is wound by switching the position of the linear rod 33d of the air cylinder 33b. This control device also controls the sewing operation of the sewing head and appropriately controls the rotation of the rotary drive source to actively rotate the selected bobbin 21, thereby ensuring that an appropriate amount of string-like material L is actively fed out from the selected bobbin 21 as the sewing operation progresses.

[0022] As is well known, a sewing head is provided with a guide device (not shown) for guiding a string-like material L to the needle base position of a sewing needle (not shown), and further, a zigzag mechanism (not shown) may be provided to zigzag the guide device to facilitate zigzag sewing of the string-like material L. The material supply device 1 according to this embodiment is applicable to any configuration of guide device and / or zigzag mechanism. A preferred form of the guide device is to provide a guide member corresponding to each bobbin 21, pass each string-like material L drawn from each bobbin 21 through each guide member in advance, and adopt a novel configuration that includes a position switching mechanism to set one of the guide members corresponding to the selected bobbin 21 to a position where it can be sewn to the needle base position of the sewing head. In this way, the guide member to be set to the sewable position can be automatically switched by the position switching mechanism, improving operability. However, the material supply device 1 according to this embodiment can also be applied to a guide device that has only one guide member, as is conventionally known. In that case, when changing the string-like material L to be sewn, it is necessary to manually replace the string-like material L that is passed through the guide member with the string-like material L drawn from the newly selected bobbin 21.

[0023] As described above, the material supply device 1 according to this embodiment is configured such that rotational motion is selectively applied by the rotary drive device 3 to one of the plurality of bobbins 21 arranged in the bobbin placement device 2, and the string-like material unwound from the bobbin 21 is supplied to the sewing head as the selected bobbin 21 rotates. This provides the excellent effect of easily and efficiently changing and switching the string-like material to be sewn. In particular, even when the weight of the bobbin 21 wound with the string-like material is heavy, the string-like material can be smoothly unwound from the bobbin 21. Therefore, in a material supply device 1 suitable for using large bobbins, this provides the excellent effect of easily and efficiently changing and switching the string-like material to be sewn.

[0024] Furthermore, by adopting a configuration in which the rotary drive device 3 includes one rotary drive source 31 and a transmission mechanism 32 that selectively transmits the rotational motion based on the rotary drive source 31 to one of the bobbins 21, the number of rotary drive sources (e.g., electric motors) 31 that the rotary drive device 3 needs to have can be reduced, contributing to a simpler and more compact configuration, and also reducing manufacturing costs.

[0025] Figure 6 shows a modified version of the above embodiment (first embodiment) as viewed from the rear side of the support plate 22. This modified version consists of a configuration in which two bobbins 21 are arranged on the support plate (support part) 22. Therefore, the switching mechanism 33 only needs to be able to selectively switch the transmission path of rotational motion based on the rotational drive source 31 to either of the two bobbins 21 on the left or right, and thus the cylinder 33b only needs to be of a type that can switch the linear position of the linear rod 33d to two positions. In Figure 6, the state in which the air cylinder 33b is extended and the linear rod 33d is set to the left position is shown by a solid line, and the state in which the air cylinder 33b is retracted and the linear rod 33d is set to the right position is shown by a dashed line. In the state shown by the solid line, the drive roller 32d is in close contact with the rotating plate 23a (O-ring 23e) of the bobbin 21 located on the left side when viewed from the rear, and the rotation of the drive roller 32d is selectively transmitted to the left bobbin 21. In the state shown by the dashed line, the drive roller 32d is in close contact with the rotating plate 23a (O-ring 23e) of the bobbin 21 located on the right side when viewed from the back, and the rotation of the drive roller 32d is selectively transmitted to the bobbin 21 on the right side.

[0026] In the above embodiment (first embodiment) and its modifications, the switching mechanism 33 uses an air cylinder 33b as a driving means for switching the angle of the swing arm 33a, but is not limited to this. For example, a rotary electric motor may be used instead of the air cylinder 33b. In that case, for example, the mechanism may be configured to move the link pin 33c of the swing arm 33a left and right via a mechanism that converts the rotation of the rotary electric motor (which replaces the air cylinder 33b) into linear motion. As another example, the rotary drive source 31 may be provided on the upper end side of the swing arm 33a, and the rotary electric motor for angle switching may be provided on the lower end side (pivot point) of the swing arm 33a. That is, by swinging the upper end side of the swing arm 33a in an arc shape in accordance with the rotation of the rotary electric motor provided on the lower end side (pivot point) of the swing arm 33a, the drive roller 32d is made to come into close contact with the O-ring 23e of the rotating body 23 corresponding to one of the bobbins 21. On the other hand, a rotary drive source 31 is attached to the upper end of the swing arm 33a, and the rotary output shaft of the rotary drive source 3 is connected to the rotation shaft of the drive roller 32d, so that the rotational motion of the rotary drive source 3 is directly transmitted to the drive roller 32d. In this case, the drive pulley 32a, transmission belt 32b, and driven pulley 32c in the transmission mechanism 32 are unnecessary. This makes it possible to selectively switch the transmission path of the rotational motion based on the rotary drive source 31 to one of the multiple bobbins 21.

[0027] Figure 7 is a perspective view of a material supply device 1 according to another embodiment of the present invention (second embodiment), and Figure 8 is a front view thereof. In this embodiment, the bobbin arrangement device 2 includes a support shaft 24 as a support part for arranging a plurality of bobbins 21 in series. The support shaft 24 rotatably supports each of the plurality of bobbins 21 arranged in series and is detachably fixed to the mounting member 4. When replacing a bobbin 21, the support shaft 24 is temporarily removed from the mounting member 4, the used bobbin 21 is pulled out from the support shaft 24, a new bobbin 21 is inserted into the support shaft 24 in its place, and then the support shaft 24 is attached to the mounting member 4.

[0028] In this second embodiment, the rotary drive device 3 also includes a rotary drive source (e.g., an electric motor) 31 and a transmission mechanism 32 that selectively transmits the rotational motion based on the rotary drive source 31 to one of the bobbins 21. The transmission mechanism 32 includes a drive roller 32d coupled to the rotary output shaft of the rotary drive source 31, and may include, for example, an appropriate variable speed gear mechanism between the rotary output shaft and the drive roller 32d. The rotational motion based on the rotary drive source 31 is transmitted to the selected bobbin 21 by the drive roller 32d being in close contact with the flange 21a of the selected bobbin 21. The switching mechanism 33 that switches the transmission path of the rotational motion includes a rotary electric motor 33e, a ball screw 33f connected to the rotation shaft of the motor 33e and extending parallel to the support shaft 24, a pair of guide shafts 33g extending parallel to the support shaft 24, and a slide 33h slidably coupled to the guide shafts 33g and displaced linearly along the guide shafts 33g. Slide 33h is connected to the screw rod of ball screw 33f by a ball screw and is driven linearly in accordance with the rotation of ball screw 33f. A rotational drive source 31 is mounted on slide 33h, and the rotational drive source 31 and drive roller 32d are displaced linearly in accordance with the linear drive of slide 33h. That is, the drive roller 32d is the working end for transmitting rotational motion based on the rotational drive source 31 to the bobbin 21, and the switching mechanism 33 switches the transmission path of the rotational motion by linearly displacing the working end (drive roller 32d).

[0029] When switching the string-like material to be sewn, the motor 33e is rotated appropriately to linearly displace the rotary drive source 31 and drive roller 32d mounted on the slide 33h, positioning the drive roller 32d in close contact with the flange 21a of the bobbin 21 to be selected. With the drive roller 32d positioned in this way, the rotary drive source 31 is rotated appropriately in accordance with the progress of the sewing operation, causing the selected bobbin 21 to rotate in response to the rotation of the drive roller 32d, and an appropriate amount of string-like material L is actively fed out from the bobbin 21.

[0030] In each of the above embodiments, the material supply device 1 corresponding to one sewing head is equipped with only one rotary drive source 31 in the rotary drive device 3, but it is not limited to this. For example, a plurality of bobbins 21 arranged in the bobbin placement device 2 may be divided into two or more groups, and the rotary drive device 3 may be equipped with a rotary drive source 31 corresponding to each group individually, and a transmission mechanism 32 for each group to selectively transmit the rotational motion based on each rotary drive source 31 to any bobbin 21 belonging to the corresponding group. In that case, the material supply device 1 corresponding to one sewing head is configured to selectively drive only one rotary drive source 31 corresponding to one group. As an example, four bobbins 21 are arranged in the bobbin placement device 2 and divided into two groups of two bobbins 21, and the rotary drive device 3 can be configured to install two sets of combinations of rotary drive source 31 and transmission mechanism 32 as shown in Figure 6 for each group.

[0031] Furthermore, from another perspective, the method of installing the bobbin 21 in the bobbin placement device 2 shown in the first embodiment (see especially Figure 3) forms a structure in which the axis of the bobbin 21 inserted into the bobbin shaft 23b is directed diagonally upward at an appropriate angle, corresponding to the inclination of the plane (front surface) of the support part (support plate 22). This brings about the advantages described above, and can therefore be advantageously implemented even when a single bobbin 21 is placed in the bobbin placement device 2. An embodiment following such an alternative perspective can be summarized as follows.

[0032] A material supply device in a sewing machine according to a different perspective is a material supply device for supplying a string-like material to be sewn in a sewing machine, comprising a bobbin arrangement device that rotatably supports a bobbin on which the string-like material is wound, the bobbin arrangement device including a rotating body that detachably mounts the bobbin with the axis of the bobbin directed diagonally upward, and a support part that rotatably supports the rotating body, and a rotary drive device that imparts rotational motion to the rotating body.

Claims

1. A material supply device for supplying string-like material to be sewn in a sewing machine, comprising: a bobbin arrangement device that rotatably supports a plurality of bobbins wound with string-like material, corresponding to one sewing head; and a rotation drive device that selectively imparts rotational motion to one of the bobbins, wherein the string-like material unwound from the selected bobbin is supplied to the corresponding sewing head as the selected bobbin rotates.

2. The material supply device in a sewing machine according to claim 1, wherein the rotary drive device includes one rotary drive source and a transmission mechanism for selectively transmitting rotational motion based on the rotary drive source to one of the bobbins.

3. The material supply device in a sewing machine according to claim 2, wherein the transmission mechanism includes a switching mechanism for switching the transmission path of rotational motion in order to selectively transmit the rotational motion based on the rotational drive source to any of the bobbins.

4. The material supply device for a sewing machine according to claim 3, wherein the transmission mechanism includes an operating end for transmitting rotational motion based on the rotational drive source to the bobbin, and the switching mechanism switches the transmission path of the rotational motion by displacing the operating end.

5. The bobbin placement device includes a support section for arranging the plurality of bobbins, and a plurality of rotating bodies that are individually coupled to each bobbin placed in the support section, thereby enabling the coupled bobbins to rotate integrally, and the transmission mechanism is configured to transmit rotational motion based on the rotational drive source to the rotating body coupled to one selected bobbin, the material supply device for a sewing machine according to claim 2.

6. The material supply device for a sewing machine according to claim 2, wherein the bobbin placement device includes a support portion that rotatably supports the plurality of bobbins, each bobbin having a flange, and the transmission mechanism is configured to transmit rotational motion based on the rotational drive source to the flange of one selected bobbin from among the bobbins supported by the support portion.

7. A material supply device for a sewing machine according to any one of claims 1 to 6, wherein the plurality of bobbins are divided into two or more groups, the rotary drive device includes a plurality of rotary drive sources, each rotary drive source is associated with each group, and the rotary drive device further includes a group-specific transmission mechanism for selectively transmitting the rotational motion based on each rotary drive source to any bobbin belonging to the corresponding group, and is configured to selectively drive only the rotary drive source corresponding to one group.

8. The bobbin placement device includes a rotating body for mounting the bobbin with the bobbin's axis pointed diagonally upward, and a support part for rotatably holding the rotating body, the material supply device for a sewing machine according to any one of claims 1 to 6.

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