Material cutting device in sewing machine

Abstract

The present invention addresses the problem of: preventing the occurrence of fraying of fibers at a cut portion of a string-shaped material; and performing a stable cutting operation. A cutting unit (210) for cutting a string-shaped material connected to an object to be sewn includes a heating member (211) that heat-melts a cut surface of the string-shaped material. In one example, the heating member functions as a cutting member, a gripping member (220) that grips a string-shaped material connected to an object to be sewn from the supply side is provided, and the string-shaped material gripped by the gripping member is brought into contact with the heating member (211), thereby thermally severing the string-shaped material. Since the string-shaped material is thermally severed, heat-melted fibers cool and solidify, and fraying of a cut end is eliminated. As another example, a cutting device (320) for cutting a string-shaped material is provided, and a cut surface of the string-shaped material cut by the cutting device is brought into contact with the heating member (211) to be heat-melted. In addition, gripping parts that respectively grip an upstream side portion and a downstream portion of the cut string-shaped material are provided, and each portion is brought into contact with the heating member in a gripped state.

Description

Material cutting device in a sewing machine

[0001] The present invention relates to a sewing machine that sews a string-like material such as a tape or a cord to a sewing object by straight stitching, and particularly to a material cutting device for cutting the string-like material at the end of sewing.

[0002] Conventionally, a needle bar 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 rotatable about its axis, and a guide device attached to this rotating body to guide a string-like material (for example, a string-like embroidery material such as a tape or a cord) to the position of the needle tip of the sewing needle, and a material supply device for supplying the string-like material to the guide device are provided. The rotation of the rotating body is controlled according to the moving direction of the fabric based on embroidery data, and while changing the orientation of the guide device so that the guiding direction of the string-like material to the needle tip is appropriate, this string-like material is sewn to the sewing object (fabric) by straight stitching, or further, the guide device is zigzagged by a zigzag mechanism and the string-like material is sewn to the sewing object by zigzag stitching. A sewing machine of this type (for example, a straight stitch hand embroidery machine) is known.

[0003] In this type of sewing machine, it is also known to provide a cutting device that automatically cuts the string-like material at the end of sewing. For example, Patent Document 1 discloses a cutting device that hooks the string-like material by the advancement and retraction of a material hooking member and brings it to the position of a cutting blade for cutting. Further, Patent Document 2 makes a clamping member movable between a retracted position away from the sewing needle and a holding position approaching the sewing needle, holds the sewn string-like material by the clamping member in the holding position, and cuts the string-like material in the held state. In any of the cutting devices, the cutting of the string-like material is performed by a mechanical cutter or scissors. Therefore, although it varies depending on the material of the string-like material, it is common for the cut ends of the string-like material after cutting to have fiber fraying. When the diameter of the string-like material is thin, this fraying is not very noticeable, but when the diameter is thick, there is a problem that the fraying becomes noticeable and the appearance deteriorates as the fraying progresses due to contact.

[0004] Japanese Patent Application Laid-Open No. 4-163361, Japanese Patent No. 5766405

[0005] The present invention has been made in view of the above-mentioned points, and aims to provide a material cutting device for a sewing machine that prevents fraying of fibers at the cut point of a string-like material and further enables stable cutting operations.

[0006] The material cutting device for a sewing machine according to the present invention is a material cutting device for cutting a string-like material in a sewing machine capable of sewing a string-like material to a workpiece, and is characterized by comprising a cutting unit for cutting the string-like material connected to the workpiece, wherein the cutting unit includes a heating member for thermally melting the cut surface of the string-like material. According to the present invention, since the cut surface of the string-like material is thermally melted, the fibers of the cut surface that have been melted by the heat cool and harden, thereby eliminating fraying of the cut edge.

[0007] In one embodiment, the heating member is a heated cutting member, and the cutting unit may further include a gripping member for gripping a string-like material connected to the workpiece, and an operating device that brings the string-like material gripped by the gripping member into contact with the cutting member, thereby causing the string-like material to be heat-melted and cut by the cutting member. With this configuration, the string-like material is cut by heat-melting it with the heated cutting member, and the fibers that have melted due to the heat cool and harden after cutting, thus eliminating fraying of the cut end. Furthermore, since the string-like material is gripped by the gripping member and then brought into contact with the cutting member, the string-like material does not slip when it comes into contact with the cutting member, allowing for a stable cutting operation. In a preferred embodiment, the gripping member is positioned to grip the string-like material upstream (on the supply side) of the cutting position by the cutting member. As a result, the gripping member grips the material portion above the cutting position, and the gripping member can maintain its grip on the string-like material on the supply side even after cutting. Therefore, it is advantageous for processing the string-like material on the supply side after cutting (for example, retracting to a predetermined position or holding it). Furthermore, the operating device is configured to bring the string-like material into contact with the cutting member by rotating the gripping member relative to the cutting member while gripping the string-like material. As a result, the movement to bring the string-like material into contact with the cutting member can be performed with a simple rotation (pivot), resulting in a simple structure. In one embodiment, a guiding member is further provided, which is positioned downstream of the gripping position by the gripping member and is configured to contact the string-like material gripped by the gripping member downstream of the gripping position and guide the string-like material toward the cutting member. With this, the string-like material can be brought closer to the cutting member while being supported at two locations: not only the gripping point by the gripping member but also the guiding member below it. This makes it even more reliable to prevent the string-like material from slipping when it comes into contact with the cutting member, and allows for reliable thermal cutting of the string-like material in a stable position.

[0008] In another embodiment, the cutting unit may include a cutting device for cutting a string-like material connected to the workpiece, and the heating member may be configured to heat-melt the cut surface of the string-like material cut by the cutting device. In this case as well, since the cut surface of the string-like material cut by the cutting mechanism is heat-melted by the heating member, the fibers of the melted cut surface cool and harden, eliminating fraying of the cut end. In one embodiment, the cutting unit may further include a gripping part for gripping the string-like material connected to the workpiece, and the cutting surface may be configured to heat-melt by bringing the cut surface of the string-like material into contact with the heating member while the string-like material cut by the cutting device is gripped by the gripping part. With this configuration, since the string-like material is gripped by the gripping part and brought into contact with the heating member, the string-like material does not escape when it comes into contact with the heating member, and the cut surface can be heat-melted in a stable state.

[0009] A front view of a sewing machine to which a material cutting device according to one embodiment of the present invention is applied. A right side view of the sewing machine shown in Figure 1, with the material cutting device omitted for convenience. A left side view showing an enlarged view of the sewing head of the sewing machine shown in Figure 1, with the material cutting device omitted for convenience. A front view showing an even more enlarged view of the area surrounding the material guide device provided at the bottom of the sewing head of the sewing machine shown in Figure 1. A left side view of the area surrounding the material guide device shown in Figure 4. A partial cross-sectional left side view showing a partial cross-section of the area surrounding the material guide device shown in Figure 5. A partial cross-sectional front view showing a partial removal and partial cross-section of the area surrounding the material guide device shown in Figure 4. A perspective view showing a partial removal of the area surrounding the material guide device shown in Figures 4 to 6. A perspective view of the area surrounding the material guide device as seen from the opposite side of Figure 8. A schematic front view for explaining the shift operation (switching operation) performed when switching the string-like material to be sewn. A right side view showing an enlarged view of the sewing head of the sewing machine shown in Figure 1, clearly indicating a material cutting device according to one embodiment of the present invention, and showing the state in which the material cutting device is set to the retracted position. An enlarged perspective view of the material cutting device set in the retracted position, viewed from the upper right at an angle. A right side view showing an enlarged portion of the sewing head of the sewing machine shown in Figure 1, illustrating the state in which the material cutting device according to one embodiment of the present invention is set in the cutting position. An enlarged perspective view of the material cutting device set in the cutting position, viewed from the upper right at an angle, illustrating the state in which the gripping member is open. A bottom view of the main part of the material cutting device, viewed from the back. A plan view and a schematic front view illustrating the cutting operation by the material cutting device. A perspective view showing a modified example of the cutting unit in the material cutting device, with the main parts extracted and shown. An exploded perspective view of the main parts of the modified example of the cutting unit shown in Figure 17. A schematic front view illustrating the cutting operation by the cutting unit shown in Figure 17.

[0010] Figure 1 is a front view of a sewing machine to which a material cutting device 200 according to one embodiment is applied. As shown in Figure 11, the material cutting device 200 is located on the rear side and is therefore not shown in Figure 1, which shows the front side. Figure 2 is a right side view of the sewing machine shown in Figure 1, and for convenience, the part of the material cutting device 200 located on the rear side is omitted. Figure 3 is a left side view showing an enlarged portion of the sewing head H of the sewing machine shown in Figure 1, and for convenience, the part of the material cutting device 200 located on the rear side is omitted. Figure 11 is a right side view showing an enlarged portion of the sewing head H of the sewing machine shown in Figure 1, clearly showing the material cutting device 200 according to one embodiment of the present invention and showing the state in which the material cutting device 200 is set to the retracted position. This sewing machine is configured to sew a string-like material, guided to the needle base position by a material guide device 6, to a workpiece (for example, fabric). The material guide device 6 is installed below one of the sewing heads H of the sewing machine, such as a lockstitch handle embroidery machine (near the needle base position), and functions to guide the string-like material to be sewn by the sewing machine to the needle base position. The material cutting device 200 functions to cut the string-like material extending from the last sewing position (needle base position) to the material guide device 6 when a series of sewing operations on the string-like material is completed.

[0011] <Supplying the string-like material> As an example, multiple sewing heads H can be arranged at regular intervals on the front of the sewing machine frame M, but in this embodiment, for the sake of explanation, only one sewing head H is shown. Above the sewing head H, a material supply device 1 is provided for supplying the string-like material to the sewing head. As an example, the material supply device 1 includes a bobbin placement device 2 that rotatably supports multiple bobbins 21 on which string-like material L is wound, and a rotation drive device (not shown) 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 arranged in the bobbin placement device 2, and the string-like material L drawn from each bobbin 21 is supplied to the sewing head H below. As one bobbin 21, which is selectively given rotational motion by the rotation drive device (not shown), rotates, the string-like material L is actively fed out from the bobbin 21 and supplied to the sewing head H. For the sake of illustration convenience, the string-like material L is omitted from the diagram as appropriate, but multiple string-like materials L (three as an example) exist in parallel along the entire path from the material supply device 1 to the material guide device 6.

[0012] The bobbin placement device 2 includes a support plate 22 on which a plurality of bobbins 21 are arranged. A bobbin 21 is set on each of the plurality of bobbin shafts 23b erected on the support plate 22, and the bobbin 21 is fixed to the bobbin shaft 23b by a stopper 23c, so that the bobbin 21 set thereon rotates in accordance with the rotation of the bobbin shaft 23b. The stopper 23c is removable, and with the stopper 23c removed, the bobbin 21 can be attached to and detached from the tip side of the bobbin shaft 23b, thereby allowing the bobbin 21 set on the bobbin shaft 23b to be replaced. The support plate 22 is fixed to the sewing machine frame M via a pair of mounting members 4.

[0013] The above-mentioned rotary drive device (not shown) selectively rotates one bobbin shaft 23b, thereby rotating one bobbin 21 in the bobbin placement device 2 via the bobbin shaft 23b, and the string-like material L is actively fed out from the bobbin 21 as the bobbin 21 rotates. For example, each bobbin 21 is a large bobbin capable of winding a large amount of string-like material, thereby reducing the frequency of bobbin replacement due to the consumption of string-like material, and thus providing a configuration suitable for the use of large amounts of string-like material. In this case, actively rotating the bobbin 21 with the above-mentioned rotary drive device (not shown) contributes to the smooth feeding of string-like material from the large (heavy) bobbin 21.

[0014] Multiple pins 25 are erected horizontally at the lower part of the support plate 22, and the string-like material drawn from each bobbin 21 is distributed and passed through the pins 25 so that the string-like material does not interfere with each other. Multiple string-like materials (for example, 3) drawn in parallel from the material supply device 1 via the pins 25 are guided to the material guide device 6 below via the intermediate guide 7. As shown in Figure 2, the intermediate guide 7 includes a first roller 71, a reversing section 72, a second roller 73, a first guide hole 74, and a second guide hole 75. The first roller 71 consists of multiple rollers (for example, 3) corresponding to each string-like material, arranged side by side in a front view (see Figure 1), and similarly, the second roller 73 consists of multiple rollers (for example, 3) corresponding to each string-like material, arranged side by side in a front view (see Figure 1). The reversing section 72 consists of multiple holes (three, for example) corresponding to each string-like material, arranged side by side in a front view, with these holes oriented horizontally (see Figure 1). The reversing section 72 is fixed at an appropriate intermediate position on a vertically extending rail 76, and the height position at which the reversing section 72 is fixed can be appropriately changed by displacing it up or down along the rail 76.

[0015] The upper end of the rail 76 is cantilevered by a mounting member 4 and fixed to a cantilevered crossbar 77 that extends horizontally forward. A first roller 71 is attached near the base of the cantilevered crossbar 77 (towards the mounting member 4, i.e., towards the rear), and a second roller 73 is attached near the tip of the cantilevered crossbar 77 (i.e., towards the front) (see Figure 2). The first guide hole 74 is provided at the lower end of the rail 76 and consists of multiple holes (for example, 3) arranged side by side, corresponding to each string-like material, and these holes are oriented vertically (see Figures 1 and 2). Note that the multiple holes (for example, 3) of the first guide hole 74 can be seen in a plan view and are therefore not visible in Figures 1 and 2. The second guide hole 75 is provided further below the first guide hole 74 and consists of multiple holes (for example, 3) arranged side by side, corresponding to each string-like material, and these holes are oriented diagonally downward, generally pointing towards the area around the needle base position.

[0016] In the intermediate guide 7, each string-like material that has passed between the pins 25 moves downwards, touching the rear of the first roller 71, passes through the hole of the reversing section 72 from rear to front, moves upwards, is folded downwards by the second roller 73, passes through the first guide hole 74, and then passes through the second guide hole 75 to be guided to the material guide device 6 below (see Figure 2). By guiding the string-like material through the first roller 71, the reversing section 72, and the second roller 73 to the first guide hole 74 below, the movement path of the string-like material moving from top to bottom in front of the sewing head H is reliably formed in front of the sewing head H (so as not to be interfered with by the sewing head H).

[0017] A material guide device 6 is provided at the lower part of the sewing head H, around the vertically moving sewing needle 12. The material guide device 6 includes a swinging part (swinging lever 51) that performs a swinging motion to swing the string-like material to be sewn in a zigzag pattern, a guide part 61 that includes a plurality (for example, 3) of guide tubes (guide members) 61a for guiding the string-like material to the vicinity of the needle base position, and a shift mechanism 62 configured to associate one guide tube (guide member) 61a with the swinging part, and to transmit the swinging motion of the swinging part to the associated guide tube (guide member) 61a. As will be described in detail later, the shift mechanism 62 includes a cam part (cam plate 63) in which a cam path (cam groove 63a and connecting groove 63b) is formed, and an engaging part (roller 51b) that engages with the cam part (cam plate 63) and is relatively movable along the cam path, and is configured to associate one guide tube (guide member) 61a with the swinging part by moving the engaging part along the cam path. Each string-like material that passes through the second guide hole 75 of the intermediate guide 7 is inserted into the corresponding guide tube (guide member) 61a, exits the guide tube (guide member) 61a, and is guided to the needle base position. However, due to the correspondence of the guide part 61 (guide tube 61a) to the oscillating part (oscillating lever 51) by the shift mechanism 62, only one selected (associated) guide tube (guide member) 61a is set to the needle base position.

[0018] <Outline of the Sewing Head> As shown in Figure 3, the sewing head H is provided with a needle bar 11 that extends vertically in the axial direction. The needle bar 11 is driven to reciprocate vertically by the rotation of the sewing machine spindle 10. A sewing needle 12 is attached to the lower end of the needle bar 11. A support cylinder 13 is attached to the outer circumference of the needle bar 11. This support cylinder 13 is guided by the inner surface of a fixed sleeve 14 fixed to the lower part of the sewing head H, enabling relative vertical movement of the needle bar 11 and rotational movement of the needle bar 11 around its axis. In addition, an engagement ring 15 is fixed to the outer circumference of the upper end of the support cylinder 13, and a drive arm 17 that moves up and down by the drive of a motor 16 is engaged with the engagement ring 15.

[0019] A presser foot support 18 is fixed to the lower end of the support cylinder 13. The presser foot support 18 is formed in a bifurcated shape at its lower end, and a key groove 18a is formed on the outer surface of one leg, with its longitudinal direction extending vertically. A presser foot body (nipple) 19 is fixed to the other leg of the presser foot support 18. When the needle bar 11 moves up and down in accordance with the rotation of the spindle 10 to perform sewing, the drive arm 17 moves up and down in conjunction with this by the motor 16, and the presser foot body 19 moves up and down via the support cylinder 13 and presser foot support 18, thereby performing presser foot movement synchronized with sewing. As is well known, an upper thread is passed through the sewing needle 12, and a bobbin mechanism (not shown) is provided below the needle plate 20. A string-like material that emerges from the tip of the guide tube 61a and is guided to the needle base position is sewn to the workpiece (not shown, e.g., fabric) placed on the needle plate 20 fixed to the upper surface of the sewing machine table (not shown) by a lockstitch using the upper and lower threads. As is well known in embroidery machines, the workpiece is stretched over an embroidery hoop (not shown), which is positioned on the sewing machine table in an X-Y drivable state and is driven in the X-Y direction for each stitch (sew) according to the embroidery pattern (sewing pattern) data.

[0020] A rotating cylinder (rotating body) 8 is attached to the outer circumference of the fixed sleeve 14. The rotating cylinder 8 is mounted concentrically with the needle bar 11, and is only capable of rotational movement around the axis of the needle bar 11. A timing pulley portion 80 is formed on the outer circumference of the upper end of the rotating cylinder 8, and a timing belt 83 is stretched between this timing pulley portion 80 and a drive pulley 82 fixed to the rotating shaft 81a of the direction control motor 81. As a result, when the direction control motor 81 is driven and the drive pulley 82 rotates, the rotating cylinder 8 rotates via the timing belt 83 and the timing pulley portion 80. On the other hand, a key member 84 that engages with the key groove 18a of the presser foot support 18 is fixed to the lower end of the rotating cylinder 8. Therefore, the presser foot support 18 (and presser foot body 19) moves up and down in accordance with the up and down movement of the support cylinder 13, and rotates around the axis of the needle bar 11 in accordance with the rotation of the rotating cylinder 8. As will be described later, the rotational motion of the rotating cylinder 8 is ultimately transmitted to the guide section 61 of the material guide device 6. The direction control motor 81, which is the rotational drive source for the rotating cylinder 8, is driven and controlled according to the embroidery pattern (sewing pattern) data, and rotates the guide section 61 of the material guide device 6 around the axis of the needle bar 11 so that the guide section 61 of the material guide device 6 appropriately points in the sewing direction for each stitch. As can be seen from Figure 3, the guide section 61 and the presser foot 19 are arranged facing each other (on opposite sides) with the needle bar 11 in between, and both rotate together in accordance with the rotation of the rotating cylinder 8.

[0021] A swinging lever (swinging part) 51 is attached to the outer circumference of the rotating cylinder 8 via a mounting bracket. The swinging lever 51 is pivotably mounted on the rotating cylinder 8, with a lever pin 52 as the pivot point, allowing it to swing left and right in the axial direction of the needle bar 11. This swinging lever 51 extends downward from the position of the lever pin 52 (forming a relatively long leg), and also includes a short arm 51a that extends laterally from the position of the lever pin 52 (see Figures 4 to 8). A roller 51b is provided at the lower end of the swinging lever 51, facing outwards (see Figure 7). Through this swinging lever (swinging part) 51, a swinging motion for swinging the string-like material in a zigzag pattern is applied to the guide part 61 of the material guide device 6.

[0022] Furthermore, an interlocking member 53 is fitted to the outer circumference of the rotating cylinder 8 so as to be able to move up and down and rotate. A connecting body 54 is fixed to the interlocking member 53, and one end of the connecting body 54 engages with a vertically elongated engagement groove 8a formed on the outer circumference of the rotating cylinder 8 (see Figures 5 to 9). Due to this engagement, the interlocking member 53 rotates together with the rotating cylinder 8 as the rotating cylinder 8 rotates, but can move up and down independently of the rotating cylinder 8 in the vertical direction. A roller 55 is attached to the tip of the arm portion 51a of the swinging lever 51 (see Figure 4), and an interlocking groove 54a is provided at the other end of the connecting body 54, and the roller 55 engages with the interlocking groove 54a of the connecting body 54. As a result, when the interlocking member 53 moves up and down, the engagement of the connecting groove 54a of the connecting body 54 and the roller 55, which move up and down together, causes the arm portion 51a of the swinging lever 51 to move up and down around the lever pin 52 as a pivot point, and the downward-extending swinging lever 51 (leg portion) swings laterally (left and right) like a pendulum around the lever pin 52 as a pivot point.

[0023] As shown in Figures 1 and 2, a staggered swing motor 50 is provided, which is the drive source for staggering the string-like material. Although not shown in detail, the rotational motion of this staggered swing motor 50 is converted into vertical motion and transmitted to the lifting member 56 (see Figures 4 and 7), causing the lifting member 56 to move up and down. In Figures 4 and 7, only the lower part of the lifting member 56 is shown, and the portion extending upward is not shown. A fork portion 56a is formed at the lower end of the lifting member 56, which protrudes approximately horizontally toward the needle bar 11, and this fork portion 56a engages with a groove portion 53a formed on the outer circumference of the interlocking member 53 (see Figures 3 to 7). Therefore, when the interlocking member 53 and the connecting body 54 move up and down due to the up and down movement of the lifting member 56 in response to the rotation of the staggered swing motor 50, the up and down movement of the connecting body 54 is transmitted to the arm portion 51a of the swing lever 51 via the linkage groove and roller 55, and converted into a left and right swinging motion of the swing lever 51 via the lever pin 52. This mechanism from the staggered swing motor 50 to the swing lever 51 corresponds to a swinging mechanism (staggered swing mechanism) that generates a swinging motion for swinging the string-like material to be sewn in a staggered pattern.

[0024] <Material Guiding Device> Figure 4 is a front view showing an enlarged view of the peripheral portion of the material guiding device 6 shown in Figure 1, Figure 5 is a left side view of the peripheral portion of the material guiding device 6 shown in Figure 4, and Figure 6 is a partial cross-sectional left side view showing a portion of the peripheral portion of the material guiding device 6 shown in Figure 5. Figure 7 is a partial cross-sectional front view showing a portion of the peripheral portion of the material guiding device 6 shown in Figure 4, and in particular, the guide part 61 of the material guiding device 6 has been removed so that the shift mechanism 62 can be viewed from the front. Figure 8 is a perspective view showing a portion of the peripheral portion of the material guiding device 6 shown in Figures 4 to 6 with some parts removed, and Figure 9 is a perspective view of the peripheral portion of the material guiding device 6 seen from the opposite side of Figure 8. The details of the material guiding device 6 will be described below with further reference to these figures.

[0025] The guide section 61 includes an inclined section 61b in which a plurality of guide tubes (guide members) 61a (three as an example) are arranged in parallel in the horizontal direction, tilted diagonally downward toward the needle base position, and a vertical section 61c extending vertically upward from the upper center of the inclined section 61b. The inclined section 61b has holes for attaching the guide tubes 61a, and the guide tubes 61a are detachable. This allows the guide tubes 61a to be changed (replaced) depending on the thickness and cross-sectional shape of the string-like material used for sewing. The vertical section 61c of the guide section 61 engages with the oscillating section (oscillating lever 51) via a cam plate 63, as described later, and is oscillated laterally (left and right) in conjunction with the oscillating section (oscillating lever 51). Here, the oscillating lever 51 and the cam plate 63 are located inside (need side) of the vertical section 61c of the guide section 61, and a slider 61d is fixed to the outside of the vertical section 61c. The slider 61d is slidably coupled to a guide rail 58 that extends horizontally, allowing it to slide horizontally. The guide rail 58 is fixed to the lower end of the support bracket 57, as will be described later. This sliding coupling functions to convert the pendulum-like swinging motion of the swing lever 51, which has the lever pin 52 as its pivot axis, into a horizontal swinging motion (reciprocating motion) and transmit it to the guide section 61.

[0026] The shift mechanism 62 includes a cam plate 63 as a cam section on which cam paths are formed. As shown in Figure 7, the cam paths formed in the cam plate 63 (cam section) include a plurality of main paths (cam grooves) 63a (three in one example) and connecting paths (connecting grooves) 63b that connect each main path (cam groove) 63a. Hereinafter, the main paths will simply be referred to as cam grooves, and the connecting paths as connecting grooves. In the cam plate (cam section) 63, each cam groove 63a arranged in parallel consists of a vertically elongated opening, and the connecting groove 63b consists of a roughly horizontally elongated opening formed to connect the lower parts of each cam groove 63a. Each cam groove 63a is provided corresponding to each guide cylinder (guide member) 61a. The cam plate (cam portion) 63 is positioned upright parallel to the swing surface of the swing lever 51, on the outside of the swing lever 51 (opposite the vertical axis of motion of the needle bar 11), and the roller 51b, which is provided outward at the lower end of the swing lever 51, engages with the cam plate (cam portion) 63 and is assembled to be movable along the cam groove 63a and the connecting groove 63b. This roller 51b not only transmits the swinging motion of the swing lever 51 for staggered swing to the guide portion 61, but also functions as a component (engaging portion) in the shift mechanism 62. The cam plate 63 is fixed to the inside (needle side) of the vertical portion 61c of the guide portion 61 and is movable integrally with the guide portion 61. As mentioned above, a slider 61d is fixed to the outside of the vertical portion 61c of the guide portion 61 and is linked to the support bracket 57 via the guide rail 58. This link allows the guide section 61 and cam plate 63 to move up and down together when the support bracket 57 is raised and lowered by the material guide lifting mechanism 9, which will be described later. When sewing a string-like material, the material guide lifting mechanism 9 lowers the support bracket 57 to set the guide section 61 and cam plate 63 to the lowest position (sewing position). On the other hand, when not sewing a string-like material, the material guide lifting mechanism 9 raises the support bracket 57 to set the guide section 61 and cam plate 63 to the highest position (retracted position).

[0027] Thus, in the shift mechanism 62, the roller 51b (engaging part) engages with the cam plate 63 (cam part) and is movable along the cam groove 63a and the connecting groove 63b, and the cam plate 63 (cam part) is coupled to the guide part 61 and is configured to move up and down and left and right together. Here, the roller 51b (engaging part) is given left and right movement by the swing mechanism (staggered swing mechanism) via the swing lever 51, and the cam plate 63 (cam part) is given up and down movement by the material guide lifting mechanism 9 via the support bracket 57. The shift mechanism 62 displaces the cam plate 63 (cam part) and the roller 51b (engaging part) relatively in the vertical and horizontal directions by a combination of driving the cam plate 63 in the up and down direction and driving the roller 51b in the left and right (lateral) direction, thereby moving the roller 51b (engaging part) relatively along the cam groove 63a and the connecting groove 63b, and thereby moving the guide part 61 (guide cylinder 61a) in the up and down and / or lateral directions.

[0028] A specific example of the cam path (cam groove 63a and connecting groove 63b) formed in the cam portion (cam plate 63) will be further explained with reference to Figure 7. Multiple cam grooves 63a (main paths) are arranged in parallel, each extending in the vertical direction, and the connecting groove 63b (connecting path) is formed to connect the lower parts of each cam groove 63a (main path). Each cam groove 63a corresponds to each guide cylinder (guide member) 61a, and when the roller 51b (engaging part) engages with one of the cam grooves 63a (main path) and is positioned near its upper end, it is the state in which one guide cylinder (guide member) 61a corresponding to that cam groove 63a is selected, that is, the state in which the selected guide cylinder 61a is set to the needle base position (a state corresponding to the swing lever 51). In the example in Figure 7, the roller 51b is engaged with the central cam groove 63a, showing the state in which the central guide cylinder 61a is selected to be set to the needle base position. Furthermore, in the example shown in Figure 7, in order to smooth the relative lateral movement of the roller 51b along the connecting groove 63b when changing (i.e., shifting) the cam groove 63a with which the roller 51b should engage, the lengths of the left and right cam grooves 63a are made shorter than the length of the central cam groove 63a, and the connecting groove 63b that connects them is formed to consist of a combination of an inclined portion and a horizontal portion. Note that this inclined portion is not limited to a straight line and may be in the shape of a circular arc.

[0029] As shown in Figure 7, when the pivot lever 51 is in a vertical position (center position), the roller 51b is engaged with the cam groove 63a corresponding to one selected guide cylinder 61a, and the pivot lever 51 is in a vertical position, the roller 51b is not in contact with the uppermost end of the cam groove 63a, and there is empty space above the roller 51b in the cam groove 63a. This empty space takes into account that the height of the roller 51b increases somewhat when the pivot lever 51 swings from side to side like a pendulum. That is, when the cam plate 63 moves horizontally from side to side in response to the swing of the pivot lever 51, the height of the cam plate 63 (i.e., the height of the uppermost end of the cam groove 63a) does not change and remains at a constant height due to the engagement of the slider 61d and the guide rail 58, but smooth horizontal movement is ensured by allowing the somewhat elevated roller 51b to enter the empty space.

[0030] The shift mechanism 6 further includes a locking member 64 for locking the horizontal movement of the cam plate 63 (cam portion) while the roller 51b (engaging portion) is moving relative to the cam groove 63a and the connecting groove 63b. As shown in Figure 7, this locking member 64 is fixed to the rotating cylinder 8 in a state where it protrudes downward. On the other hand, a recess 63c is provided on the upper part of the cam plate 63, positioned opposite the locking member 64. When the support bracket 57 is raised by the material guide lifting mechanism 9 to set the guide portion 61 and the cam plate 63 to the uppermost position (retracted position), the locking member 64 fits into the recess 63c, locking the lateral movement of the cam plate 63.

[0031] When performing a zigzag stitch, the guide section 61 and the cam plate 63 are set to the lowest position (sewable position). For example, as shown in Figure 7, when the roller 51b is engaged with the central cam groove 63a, the central guide cylinder 61a of the guide section 61 is linked to the swing lever 51 (i.e., set to the needle base position), and stitching is performed on the string-like material guided to the needle base position by this central guide cylinder 61a. When the swing lever 51 is swung from side to side by the swing mechanism (zigzag swing mechanism) described above, the cam plate 63 moves horizontally from side to side via the roller 51b engaged with the central cam groove 63a. As a result, the guide section 61 moves horizontally from side to side around the central guide cylinder 61a engaged with the roller 51b, and zigzag stitching is performed on the string-like material guided by the central guide cylinder 61a set to the needle base position, following this horizontal movement. Furthermore, since the presser foot 19 is located on the opposite side of the guide section 61 with the needle base position in between, only the string-like material currently selected for sewing, guided by the central guide cylinder 61a set at the needle base position, is pressed against the workpiece (not shown) by the presser foot 19 as the needle 12 descends. Also, as will be described later, a material holding mechanism (material holding device) 100 is located on the opposite side of the guide section 61 with the needle base position in between, and any string-like material that has not been selected is held by a holding member 101 provided in this material holding mechanism (material holding device) 100.

[0032] Next, the shift operation (string material switching operation) performed by the shift mechanism 62 to switch the string material to be sewn will be explained with reference to Figure 10. Figure 10 is a schematic front view illustrating the shift operation (switching operation) performed by the shift mechanism 62 when switching the string material to be sewn. For convenience, only the relationship between the swing lever 51 and the cam plate 63 is shown, and the relative positional relationship of the guide part 61 is also shown in part for reference. As mentioned above, the guide part 61 moves horizontally and vertically integrally with the cam plate 63. Figure 10(a) shows the state in which the roller 51b is engaged with the central cam groove 63a, similar to Figure 7. Figure 10 shows the shift operation from the state in (a) where the central guide cylinder 61a corresponding to the central cam groove 63a is associated with the swing lever 51 (set to the needle base position), to the state in (d) where the left guide cylinder 61a corresponding to the left cam groove 63a is associated with the swing lever 51 (set to the needle base position).

[0033] First, as shown in Figure 10(b), the material guide lifting mechanism 9 raises the support bracket 57 to set the cam plate 63 (and guide portion 61) to its highest position. At this time, the cam plate 63 rises along the central cam groove 63a, guided by the roller 51b of the swing lever 51, until the roller 51b reaches the connecting groove 63b. In this state, the locking member 64 fits into the recess 63c at the top of the cam plate 63.

[0034] Next, as shown in Figure 10(c), with the cam plate 63 (and guide portion 61) set to the highest position, the swing lever 51 is swung to the left to a predetermined limit position. As a result, the roller 51b of the swing lever 51 moves to the left along the connecting groove 63b. During this leftward movement, the lateral movement of the cam plate 63 is locked by the locking member 64, preventing the cam plate 63 from moving in accordance with the lateral movement of the swing lever 51 (roller 51b), thereby allowing the roller 51b to move to the limit position to the left along the connecting groove 63b.

[0035] Next, as shown in Figure 10(d), while maintaining the leftmost limit position of the swing lever 51, the material guide lifting mechanism 9 lowers the support bracket 57 to move the cam plate 63 (and guide portion 61) to its lowest position. As the cam plate 63 descends, the lock on the cam plate 63 by the locking member 64 is released, and the cam plate 63 slides to the right along the connecting groove 63b, guided by the roller 51b, until the roller 51b engages with the left cam groove 63a. In this way, the shift operation (string material switching operation) by the shift mechanism 62 is completed, and the left guide cylinder 61a is linked to the swing lever 51 (set to the needle base position).

[0036] After the shift operation is completed, the machine enters a state where it is ready to sew onto the string-like material guided by the left-side guide cylinder 61a, which is set to the needle-start position. As described above, when the swinging lever 51 is swung from side to side by the swinging mechanism (zigzag swing mechanism), the cam plate 63 moves horizontally from side to side via the roller 51b engaged with the left-side cam groove 63a, and zigzag stitching is performed on the string-like material guided by the left-side guide cylinder 61a, which is set to the needle-start position, in accordance with this horizontal movement.

[0037] When setting the right-side guide cylinder 61a to the needle base position, the shift operation by the shift mechanism 6 can be performed in the same manner as described above (but in the reverse direction). For example, by raising the cam plate 63 (and guide portion 61) to the highest position from the state shown in Figure 10(d), the cam plate 63 slides to the left along the left-side cam groove 63a and connecting groove 63b, guided by the roller 51b, and is set to the same state as shown in Figure 10(c). Next, with the cam plate 63 (and guide portion 61) still set to the highest position, the swing lever 51 is swung to the right to a predetermined limit position, causing the roller 51b of the swing lever 51 to move relatively to the right along the connecting groove 63b. Next, while maintaining the rightward limit position of the swing lever 51, the material guide lifting mechanism 9 lowers the support bracket 57, moving the cam plate 63 (and guide portion 61) to its lowest position. As a result, the cam plate 63 slides to the left along the connecting groove 63b, guided by the roller 51b, until the roller 51b engages with the right-side cam groove 63a. In this way, the shift operation (string-like material switching operation) by the shift mechanism 62 is completed, and the right-side guide cylinder 61a, corresponding to the right-side cam groove 63a, is linked to the swing lever 51 (set to the needle base position).

[0038] To switch from a state where the left or right guide cylinder 61a is set to the needle base position to a state where the central guide cylinder 61a corresponding to the central cam groove 63a is set to the needle base position, the cam plate 63 (and guide part 61) is raised to the highest position, causing the roller 51b to descend relatively along the left or right cam groove 63a, and then move relatively to the center along the connecting groove 63b, setting it to the same state as in Figure 10(b). Then, by lowering the cam plate 63 (and guide part 61) to the lowest position, the roller 51b is engaged with the central cam groove 63a as shown in Figure 10(a). As a result, the central guide cylinder 61a corresponding to the central cam groove 63a is associated with the swing lever 51 (set to the needle base position).

[0039] In this embodiment, the guide section 61 includes a plurality of guide cylinders 61a (guide members), so that it can guide different string-like materials. Furthermore, the shift mechanism 62 is configured to associate one guide cylinder 61a (guide member) with the oscillating lever 51 (oscillating part) by relatively moving the roller 51b (engaging part) along the cam groove 63a and the connecting groove 63b (cam path). As a result, any one of the plurality of guide cylinders 61a (guide members) can be selected to associate with the oscillating lever 51 (oscillating part). By shifting the guide section 61 laterally, the selected guide cylinder 61a (guide member) is set to the needle base position, and the oscillating motion for staggered swing is transmitted to the guide cylinder 61a (guide member) set to the needle base position by the oscillating lever 51 (oscillating part). Therefore, when switching between string-like materials to be sewn, there is no need to change the string-like material to the guide device (guide member) as in conventional technology which has only one guide device (guide member), thus saving labor. Furthermore, since one oscillating mechanism (oscillating part) can be used for zigzag stitching of different types of string-like materials, zigzag stitching performed while switching between different types of string-like materials can be realized with a simplified configuration.

[0040] <Material Guide Lifting Mechanism> As shown in Figures 1 to 9 (especially Figures 8 and 9), the material guide lifting mechanism 9 includes a lifting plate 91 configured to move up and down along the axial direction of the needle bar 11, and a rotating ring 92 rotatably supported on the lifting plate 91 so as to be able to rotate around the axis of the needle bar 11, and configured to move up and down together with the lifting plate 91. As shown in Figures 1 and 3, an air cylinder 93 is fixed to the left side of the sewing head H as a drive source for moving the lifting plate 91 up and down, and a connecting rod 94 is connected to the lower end of a cylinder rod 93a that extends downward and retracts upward. The lower end of the connecting rod 94 is connected to a predetermined location on the upper surface of the lifting plate 91, and the lifting plate 91 moves up and down in accordance with the extension and retraction of the air cylinder 93.

[0041] As shown in Figures 8 and 9, the lifting plate 91 has an annular shape, with a rotating ring 92 positioned inside it, and the rotating cylinder 8 (rotating body) positioned in the central opening of the rotating ring 92. The lifting plate 91 has three notches 91a formed on its inside at approximately equal intervals, and guide rollers (bearings) 91b are provided in each notch 91a. The guide rollers 91b are rotatably pivoted on a support member 91c which is fixed to the upper surface of the lifting plate 91 with screws. The rotating ring 92 has an outer circumferential surface that protrudes in a circular arc shape in cross-section, and its outer circumferential surface fits onto the guide rollers 91b, thereby supporting it to rotate freely inside the lifting plate 91. A connecting member 92a is fixed to the upper surface of the rotating ring 92, and this connecting member 92a is provided with an inwardly opening, vertically elongated engagement groove 92c (Figure 9). A vertically elongated guide body 92b, fixed to the side surface of the rotating cylinder 8 via a mounting bracket, is slidably engaged with the engagement groove 92c of the connecting member 92a. As a result, the rotating ring 92 can move up and down relative to the rotating cylinder 8 (rotating body) and rotate together with the rotating cylinder 8 (rotating body).

[0042] A support bracket 57 extending downward is attached to the lower surface of the rotating ring 92. As described above, a guide rail 58 is fixed to the lower end of this support bracket 57, and a slider 61d is connected to the guide rail 58. As a result, in the material guide lifting mechanism 9, extending or retracting the air cylinder 93 causes the connecting rod 94, lifting plate 91, rotating ring 92, support bracket 57, and guide rail 58 to move down or up together, and the guide portion 61 and cam plate 63 move down or up together via the slider 61d connected to the guide rail 58. On the other hand, when the rotating cylinder 8 rotates, the rotating ring 92 rotates together due to the engagement of the guide body 92b and the connecting member 92a, and consequently, the guide portion 61 and cam plate 63 rotate via the support bracket 57, guide rail 58, and slider 61d. In summary, the material guide lifting mechanism 9 is configured such that a material guide device 6, including the guide section 61 and the cam plate 63, is mounted on a rotating ring 92, and the material guide device 6 rotates together with the rotating ring 92 and is raised and lowered by the lifting plate 91.

[0043] According to this embodiment, since a material guide lifting mechanism 9 is used that is configured to rotate and raise / lower the material guide device 6 independently, it is possible to provide a configuration suitable for rotating and raising / lowering the material guide device 6, which tends to become heavier when equipped with multiple guide cylinders 61a. The drive source of the material guide lifting mechanism 9 is not limited to an air cylinder 93, but may also be any other appropriate linear drive source, such as a combination of a rotary electric motor and a rotary-to-linear conversion mechanism (e.g., a ball screw), or a linear rail. Furthermore, if a drive source such as an electric motor that can arbitrarily control the stopping position is used as the drive source of the material guide lifting mechanism 9, it is advantageous because the lowest position of the guide section 61 can be variably set according to the thickness of the string-like material and / or the object to be sewn. In other words, the drive source of the material guide lifting mechanism 9 can be configured to arbitrarily adjust the height, including the highest and lowest positions of the lifting plate 91.

[0044] <Material holding mechanism> A material holding mechanism (material holding device) 100 disposed on the opposite side of the guide portion 61 across the vertical axis of movement of the sewing needle 12 includes holding members 101 for holding respectively the string-shaped materials guided by the guide cylinders (guide members) 61a, provided in parallel in association with the guide cylinders (guide members) 61a (see FIGS. 5 to 9). A slider 103 is fixed to the holding member 101 via a bracket 102. As shown in FIGS. 5 and 6, a support bracket 104 extending downward is attached to the lower surface of the rotary ring 92, and a guide rail 105 is fixed to the lower end of the support bracket 104. The guide rail 105 extends horizontally parallel to the guide rail 58, and the slider 103 of the holding member 101 is slidably coupled to the guide rail 105 so as to be slidable in the horizontal direction. The bracket 102 of the holding member 101 is connected to the cam plate 63 via a pair of left and right connecting members 106. Therefore, the material holding mechanism 100 moves integrally with the guide portion 61 (rotates, moves up and down, and moves horizontally) while maintaining the correspondence between each holding member 101 and the guide cylinder (guide member) 61a.

[0045] For example, the holding member 101 has a hook-shaped fiber surface on its lower surface, and is configured to hold the corresponding string-like material by pressing it against the hook-shaped fiber surface from below, thereby entangling it with the hook-shaped fiber surface. This structure, in which the string-like material is held on the lower side (hook-shaped fiber surface) of the holding member 101, is advantageous because it makes it easier to release the hold of the string-like material guided by the guide tube (guide member) 61a set at the needle base position. In other words, when sewing begins on a string-like material guided at the needle base position, even if the string-like material is held by the corresponding holding member 101, the hold by the holding member 101 can be automatically released when the string-like material guided at the needle base position is pushed downward by the presser foot 19 at the time of the first needle drop. On the other hand, string-like materials guided by other guide tubes (guide members) 61a that are not set at the needle base position remain held by their respective holding members 101, and since the material holding mechanism 100 moves integrally with the guide section 61 during sewing, the string-like materials that are not selected (not used) do not move irregularly and interfere with the sewing operation. The holding structure of the holding member 101 is not limited to a hook-shaped fiber surface, but any other arbitrary structure can be adopted. Furthermore, the material holding mechanism (material holding device) 100 is not limited to the illustrated example, but for example, the holding members 101 may be arranged near each guide tube (guide member) 61a and connected so that they move integrally with the guide section 61 (rotate, move up and down, and move horizontally), in which case the guide rail 105 and connecting members 106 etc. become unnecessary, resulting in a considerably simpler structure.

[0046] <Material Cutting Device> As shown in Figure 11, the material cutting device 200 is suspended from the sewing machine frame M via a mounting bracket 201 on the back side of the sewing head H. While the sewing head H is performing the sewing operation of the string-like material, the material cutting device 200 is set to the retracted position as shown in Figure 11. Figure 12 is an enlarged perspective view of the material cutting device 200 set to the retracted position, viewed from the upper right, showing the gripping member 220 of the material cutting device 200 in the closed state. When the sewing operation of the string-like material is completed and the string-like material connected from the guide part 61 of the material guide device 6 (the supply side of the string-like material) to the workpiece to be sewn below (for example, fabric) is cut, the material cutting device 200 is set to the cutting position as shown in Figure 13. Figure 14 is an enlarged perspective view of the material cutting device 200 set to the cutting position, viewed from the upper right, showing the gripping member 220 in the open state (before gripping the string-like material).

[0047] The material cutting device 200 is broadly divided into a cutting unit 210 and a lifting mechanism (moving device) 240. The cutting unit 210 includes a heating member 211 made of an electric heating wire material such as nichrome wire, a gripping member 220 for gripping a string-like material connected from the guide section 61 (supply side) to the workpiece, and an operating device 230 that performs an operation to cut (i.e., heat-seal) the string-like material gripped by the gripping member 220 with the heating member 211. In this cutting unit 210, the heating member 211 functions as a heated cutting member, so it will be referred to as the cutting member 211 from now on. The gripping member 220 is positioned above the cutting member 211 so as to grip the string-like material upstream of the cutting position of the cutting member 211, and is rotatable (pivotable) around a pivot portion 220a. The operating device 230 rotates the gripping member 220 relative to the cutting member 211 while gripping the string-like material L, causing the string-like material L gripped by the gripping member 220 to come into contact with the cutting member 211 and be heat-cut. The lifting mechanism (moving device) 240 is configured to move the cutting unit 210 between a retracted position (Figure 11) and a cutting position (Figure 13). The cutting position is near the needle base, while the retracted position is away from the needle base and located above it, so this movement is an oblique lifting motion.

[0048] The gripping member 220 includes a substantially L-shaped catching lever (first member) 221 pivotally assembled to a pivot portion 220a, and a linear rocking lever (second member) 222 pivotally assembled to the pivot portion 220a. The two are pivotable independently of each other. The actuating device 230 includes an air cylinder 231 and a link 233 connected to a linear motion rod 232 of the air cylinder 231. The tip of the link 233 is pivotally supported at one end of the catching lever (first member) 221. Thus, according to the extension and contraction of the rod 232 of the air cylinder 231, the catching lever 221 swings around the pivot portion 220a. When the rod 232 of the air cylinder 231 retracts, the catching lever (first member) 221 rotates counterclockwise in plan view, the catching lever (first member) 221 approaches the rocking lever (second member) 222, and the gripping member 220 is closed. By closing the gripping member 220, a string-shaped material can be gripped. On the other hand, when the rod 232 of the air cylinder 231 extends, the catching lever (first member) 221 rotates clockwise in plan view, the catching lever (first member) 221 moves away from the rocking lever (second member) 222, and the gripping member 220 is opened. The cutting member 211, the gripping member 220, and the actuating device 230 (air cylinder 231) are fixed to the base portion 212 and integrated as a cutting unit 210. In the illustrated example, the main body portion of the rocking lever 222 is located below the catching lever 221, and a clamping member 222a is fixed to the upper surface of the main body portion. This clamping member 222a is at the same height as the catching lever 221. By sandwiching the string-shaped material between the catching lever 221 and the clamping member 222a (rocking lever 222) at the same height when the gripping member 220 is closed, the string-shaped material is securely gripped.

[0049] Figure 15 is a bottom view of the main part of the material cutting device 200 (the cutting member 211 and the gripping member 220) as seen from the back, showing the gripping member 220 in a closed state. A guide lever (guide member) 213 is positioned on the back side, or below, of the capture lever (first member) 221 of the gripping member 220 (i.e., downstream of the gripping position of the string-like material by the gripping member 220). The guide lever 213 is assembled to the capture lever 221 via appropriate bosses so as to swing integrally with the capture lever 221 around the pivot portion 220a. The heated cutting member 211 is fixed to the back surface of the base portion 212 via a mounting member 214 at a position lower than the capture lever 221 and higher than the guide lever 213. The structure allows the cutting member 211 to pass between the capturing lever (first member) 221 and the guiding lever (guiding member) 213 when they rotate together.

[0050] As shown in Figure 15, a tension spring 215 is installed between one end of the swing lever (second member) 222 and an appropriate location on the back surface of the base member 212. The tension spring 215 is biased in the contraction direction, so it is contracted when unloaded. This tension spring 215 extends when the capture lever (first member) 221, which rotates counterclockwise in a plan view, comes into contact with the swing lever (second member) 222 and rotates further counterclockwise, allowing the swing lever (second member) 222 to rotate counterclockwise together with the capture lever (first member) 221. On the other hand, when the capture lever (first member) 221 rotates clockwise in a plan view (i.e., when the gripping member 220 opens), the restoring force of the tension spring 215 returns the swing lever (second member) 222 (rotates counterclockwise and returns to its original position).

[0051] For convenience, Figure 12 shows the gripping member 220 in a closed state, and Figure 14 shows the gripping member 220 in an open state. However, the opening and closing of the gripping member 220 can be arbitrarily controlled by the operating device 230 (air cylinder 231). That is, in the retracted position as shown in Figure 12, the gripping member 220 can be opened by extending the rod 232 of the air cylinder 231, as described above, and the gripping member 220 can be closed by retracting the rod 232. Similarly, in the cutting position as shown in Figure 14, the gripping member 220 can be closed by retracting the rod 232 of the air cylinder 231, as described above, and the gripping member 220 can be opened by extending the rod 232. Although not specifically shown, an electronic control device (including, for example, a microcomputer unit and program memory, etc.) for controlling the extension and retraction of the air cylinder 231 is attached to this sewing machine, and the opening and closing control of the gripping member 220 can be performed automatically.

[0052] The base portion 212 of the cutting unit 210 is connected to the lifting mechanism (moving device) 240 via a mounting bracket 216. The lifting mechanism (moving device) 240 includes an electric motor 241 for lifting and lowering, a drive arm 243 attached to the rotation axis 242 of the electric motor 241, and a combination of a linear guide portion 244 and a slider 245 for transmitting the movement of the drive arm 243 as a predetermined diagonal lifting motion to the cutting unit 210 (more specifically, the mounting bracket 216).

[0053] The electric motor 241 is fixed to the mounting bracket 201, and the linear guide section 244 is mounted to the mounting bracket 201 at an angle so as to guide a predetermined diagonal upward and downward movement. The slider 245 is slidably coupled to the linear guide section 244 and fixed to the mounting bracket 216 of the cutting unit 210 via appropriate spacers 248. The drive arm 243 has a guide groove (elongated hole) 243a formed therein, and the mounting bracket 216 is provided with a roller 217 that is slidably coupled to the guide groove 243a. Stoppers 244a and 244b are provided at both ends of the linear guide section 244 to prevent the slider 245 from overrunning.

[0054] As shown in Figures 12 and 14, the linear guide section 244 is attached to the mounting bracket 201 via a pair of swing arms 246a and 246b. One end (upper end) of each swing arm 246a and 246b is pivotably fixed to the mounting bracket 201, and the other end (lower end) is pivotably fixed to the linear guide section 244. An upper limit stopper 202a and a lower limit stopper 202b are also fixed to the mounting bracket 201, defining the upper and lower limits of the swinging motion of the swing arms 246a and 246b. Furthermore, a torsion spring 247 biased clockwise (downward direction) in a right-side view is provided at one end (upper end) of the upper swing arm 246.

[0055] As shown in Figure 12, when the material cutting device 200 is set to the retracted position, the upper swing arm 246a is in contact with the upper limit stopper 202a, and the drive arm 243 is swung to the far right. To lower the material cutting device 200 from this retracted position to the cutting position, the drive arm 243 is swung clockwise (to the left in the figure) by rotating the electric motor 241 clockwise. The clockwise swinging motion of the drive arm 243 drives the roller 217, which is slidably coupled to the guide groove 243a, diagonally downward, and as the swing arms 246a and 246b swing clockwise, the linear guide section 244 rotates clockwise as it descends, and the mounting bracket 216 is moved diagonally downward together with and along the linear guide section 244 via the roller 217. As a result, the cutting unit 210 attached to the mounting bracket 216 moves diagonally downward together with and along the linear guide section 244. Subsequently, when the swinging arm 246b contacts the stopper 202b, the rotational descent of the linear guide section 244 is stopped. However, due to the continued swinging motion of the drive arm 243, the mounting bracket 216, i.e., the cutting unit 210, descends further along the linear guide section 244. When the cutting unit 210 has descended to a predetermined cutting position, the rotation of the electric motor 241 is stopped, and the descent of the cutting unit 210 along the linear guide section 244 is stopped. As a result, the material cutting device 200 is set to the cutting position as shown in Figures 13 and 14. In order to allow the gripping member 220 to capture the string-like material at the cutting position, the gripping member 220 is opened before the material cutting device 200 begins to descend (or even during the descent).

[0056] As shown in Figure 14, when the material cutting device 200 is set to the cutting position, the lower swing arm 246b is in contact with the lower limit stopper 202b, and the slider 245 is in contact with the lower limit stopper 244b of the linear guide section 244, and the drive arm 243 is swung to the leftmost end. To raise the material cutting device 200 from this cutting position to the retracted position, the electric motor 241 is rotated counterclockwise, causing the drive arm 243 to swing counterclockwise (to the right in the figure). Due to the counterclockwise swinging motion of the drive arm 243, the cutting unit 210 moves diagonally upward together with and along the linear guide section 244, in the opposite manner to when it was lowered. After that, when the cutting unit 210 has risen to the retracted position, the rotation of the electric motor 241 is stopped, and the upward movement of the cutting unit 210 along the linear guide section 244 is stopped. As a result, the material cutting device 200 is set to the retracted position as shown in Figures 11 and 12. Although not specifically shown, an electronic control device (including, for example, a microcomputer unit and program memory, etc.) for controlling the rotation of the electric motor 241 is attached to this sewing machine, thereby enabling automatic control of the lifting and lowering (movement) of the material cutting device 200.

[0057] <Cutting Operation> When a series of sewing operations is completed in which a string-like material L guided by a selected guide tube 61a (guide member) is sewn to the workpiece, the string-like material L extending from the guide tube 61a (unsewn string-like material) is connected to the workpiece. The material cutting device 200 functions to cut the string-like material L that is connected to the guide tube 61a diagonally above the last sewing position on the workpiece at one point. Figure 16 is a plan view illustrating the cutting operation of the string-like material L by the material cutting device 200 in several steps. The cutting operation will be described below with reference to Figures 11 to 16.

[0058] Figure 16(a) shows the gripping member 220 and its surrounding parts in a state where the string-like material L has entered between the capture lever (first member) 221 and the swinging lever (second member) 222 of the open gripping member 220. Figure 16(b) shows the gripping member 220 and its surrounding parts in a state where the string-like material L is gripped by the closed gripping member 220. Figure 16(c) shows the gripping member 220 and its surrounding parts in a state where the string-like material L gripped by the gripping member 220 is in contact with the cutting member 211. Figure 16(d) shows the gripping member 220 and its surrounding parts in a state where the string-like material L has been cut by the cutting member 211. In parts (a) to (d) of Figure 16, the upper part is a plan view and the lower part is a schematic front view shown for reference.

[0059] When the series of sewing operations in which the string-like material L is sewn onto the workpiece is completed, the material cutting device 200 is set to the retracted position as shown in Figure 11. At this time, the rotational position of the guide cylinder 61a around the needle bar's vertical movement path (sewing completion position) is arbitrary, but as an example, it is assumed to be located in the front (left side in the figure) as shown in Figure 11. If the rotational position of the material guiding device 6, including the guide cylinder 61a, around the needle bar's vertical movement path is expressed as an angle with the front position being 0 degrees, then the left position can be expressed as 90 degrees, the back position as 180 degrees, and the right position as 270 degrees. Here, when cutting the string-like material, in order to avoid cutting the upper thread hanging from the sewing needle 12 and connected to the workpiece, the cutting operation is performed on the left or right side of the sewing needle 12 when viewed from the front. Therefore, when cutting string-like material, the material guide device 6, including the guide cylinder 61a, is set to a rotation position of 90 degrees (left side) or 270 degrees (right side), and the cutting position of the material cutting device 200 is set to the left or right side of the sewing needle 12 when viewed from the front. In the example shown in Figure 13 (right side view), the material guide device 6, including the guide cylinder 61a, is located on the opposite side of the material holding mechanism (material holding device) 100 that is visible in Figure 13, indicating that the material guide device 6 is set to the rotation position of 90 degrees (left side). Therefore, in this example, the cutting position of the material cutting device 200 is set to the left side of the sewing needle 12 when viewed from the front.

[0060] To cut the string-like material, the lifting mechanism (moving device) 240 is driven in the manner described above to lower the cutting unit 210, and the material cutting device 200 is set to the cutting position as shown in Figure 13. At this time, the material guide device 6 is rotated to a predetermined position of 90 degrees (to the left) from the sewing end position. As the cutting unit 210 descends, the gripping member 220 is in an open state as shown in Figure 14. Therefore, as shown in Figure 16(a), when the cutting unit 210 reaches the cutting position, the rising portion of the string-like material L, which connects from the last sewing position on the workpiece to the guide cylinder 61a diagonally above it, enters between the capture lever (first member) 221 and the swing lever (second member) 222 of the open gripping member 220.

[0061] In the state shown in Figure 16(a), the air cylinder 231 is driven to retract the rod 232 of the gripping member 220 in order to grip the string-like material L with the gripping member 220. As a result, the capture lever 221 is rotated counterclockwise in a plan view, and the string-like material L is clamped between it and the swing lever 222 (clamping member 222a), as shown in Figure 16(b). At this time, the guide lever (guide member) 213, which is rotated counterclockwise integrally below the capture lever (first member) 221, comes into contact with the portion of the string-like material L below the clamping position.

[0062] With the gripping member 220 gripping the string-like material L in this manner, when the rod 232 of the air cylinder 231 is further retracted, the capture lever 221 is rotated further counterclockwise, and together with this, the swing lever 222 is rotated counterclockwise against the tension spring 215. As a result, the gripping member 220 approaches the cutting member 211 while still gripping the string-like material L, and thus the string-like material L gripped by the gripping member 220 is brought closer to the cutting member 211. Then, as shown in Figure 16(c), the string-like material L gripped by the gripping member 220 comes into contact with the cutting member 211, and the thermal cutting of the string-like material L by the cutting member 211 begins.

[0063] Furthermore, during the process from the state shown in Figure 16(b) to the state shown in Figure 16(c) (and in subsequent processes), the guide lever 213, which is integrally rotated counterclockwise below the capture lever 221, contacts the portion of the string-like material L below the gripping position, actively guiding this portion of the string-like material L counterclockwise (towards the cutting member 211). Therefore, the string-like material L can be brought closer to the cutting member 211 while being supported at two points: not only at the gripping point by the gripping member 220, but also at the guide lever (guide member) 213 below (downstream). This prevents the string-like material L from slipping away when it comes into contact with the cutting member 211, and ensures that the thermal cutting of the string-like material L can be performed reliably in a stable position.

[0064] After the string-like material L, gripped by the gripping member 220, is brought into contact with the cutting member 211, the rod 232 of the air cylinder 231 is further retracted, causing the capture lever 221 to rotate further counterclockwise, and together with this, the swing lever 222 rotates counterclockwise against the tension spring 215. Therefore, as shown in Figure 16(d), the gripping member 220 passes through the cutting member 211 while still gripping the string-like material L, thereby completely thermally cutting the string-like material L. In this state, the string-like material L connected to the upper guide cylinder 61a remains gripped by the gripping member 220, but the end portion of the string-like material connected to the final sewing position below will fall freely as a result of the cutting. Here, since the cutting of the string-like material L by the cutting member 211 is thermal cutting, the fibers of the string-like material L that have been melted by the heat cool and harden after cutting, so no fraying occurs at the cut end.

[0065] After cutting the string-like material L in this manner, the material guide device 6 is rotated back to its predetermined position at the front (0 degrees). This sets the holding member 101 of the material holding mechanism 100 to its predetermined position at the rear (180 degrees) (a position on the lifting trajectory of the cutting unit 210). In this state, the lifting mechanism (moving device) 240 is driven in the manner described above to raise the cutting unit 210. During this raising process, the string-like material L, which extends from the guide cylinder 61a of the material guide device 6 and is gripped by the gripping member 220, becomes capable of being held by the holding member 101 of the material holding mechanism 100. At an appropriate point after the string-like material L is capable of being held by the holding member 101 of the material holding mechanism 100, the air cylinder 231 is extended in the manner described above. As a result, the gripping member 220 opens, releasing the grip on the string-like material L, and the released string-like material L is then held by the holding member 101 of the material holding mechanism 100. Finally, when the cutting unit 210 rises to the retracted position, the series of cutting operations is completed.

[0066] <Modifications of the Cutting Unit> In the above embodiment, the cutting unit 210 in the material cutting device 200 is configured to cut string-like material using a heating cutting member 211 exclusively. However, it is not limited to this, and it may be modified to cut string-like material using a mechanical cutting device (e.g., a cutting scalpel) and then heat-melt the cut surface with the heating member 211. For example, if the string-like material contains a material that is not easily heat-melted, such as rubber, in its core, using a mechanical cutting device in combination is preferable because it enables rapid cutting. Figure 17 is a perspective view showing the main part of the cutting unit 210 modified to include a mechanical cutting device 320 in this way. Figure 18 is an exploded perspective view of the main part of the cutting unit 210 shown in Figure 17.

[0067] In Figure 17, the cutting unit 210 includes a cutting device 320, a heating element 211, and the actuator 230, and is attached to the base portion 212 in the same way as the cutting unit 210 shown in Figure 14, etc. The shape and structure of the base portion 212 will be appropriately modified to differ from those shown in Figure 14, etc., depending on the specific structure of this modified example. In this modified example as well, the actuator 230 of the cutting unit 210 has an air cylinder 231 as its drive source, similar to Figure 14, etc., and the linear motion of the linear rod 232 of the air cylinder 231 is transmitted to the cutting device 320 as rotational motion via a link 233, but these related components are not shown in Figure 17. In Figure 17, the tip of the link 233 is pivotally supported at one end of a capture lever 305 which is bent in a roughly "L" shape (or boomerang shape). The capture lever 305 is pivotally assembled to a pivot portion 306 in its middle section.

[0068] The cutting device 320 includes a movable blade 321 and a fixed blade 322. The movable blade 321 is fixed to the back side of the other end of the capture lever 305 and is configured to pivot around the pivot portion 306 in accordance with the movement of the capture lever 305. The fixed blade 322 is fixed in a predetermined position on the base portion 212. When the linear rod 232 of the air cylinder 231 is extended, as shown in Figure 17, the movable blade 321 moves away from the fixed blade 322, and the space between the two blades of the cutting device 320 is opened. By retracting the linear rod 232 of the air cylinder 231, the capture lever 305 rotates counterclockwise in a plan view, and the movable blade 321 approaches the fixed blade 322, performing an operation to cut the string-like material between the two blades. As an example, the movable blade 321 is configured to rotate horizontally and cuts the string-like material between the two blades when extended vertically. This cutting separates the string-like material into an upper (upstream) portion and a lower (downstream) portion. The separated upstream portion of the string-like material is connected to the supply source, and the downstream portion of the string-like material is connected to the final needle drop point on the workpiece. The cutting operation performed by the cutting device 320 can be automatically controlled by the electronic control device (e.g., a microcomputer unit and program memory, etc.) for controlling the extension and retraction of the air cylinder 231.

[0069] As an example, the cutting unit 210 further includes first and second gripping parts 324 and 325 that grip the upstream and downstream portions of the cut string-like material, respectively. By bringing the cut surfaces of the upstream and downstream string-like material gripped by each gripping part 324 and 325 into contact with the heating member 211, the cut surfaces of the string-like material are heated and melted. As a result, the cut ends of the string-like material cool and harden after being heated and melted, preventing fraying of the material fibers at the cut ends, and thereby improving the quality of the finished product to which the string-like material is sewn.

[0070] The first gripping portion 324, which grips the upstream portion of the string-like material, is positioned on the upper surface of the base portion 212 and consists of a combination of an upper capturing member 324a and an upper receiving member 324b. The upper capturing member 324a is fixed to the upper surface of the other end of the capturing lever 305 and is configured to pivot around the pivot portion 306 in accordance with the movement of the capturing lever 305. That is, the upper capturing member 324a is located above the movable scalpel 321 and pivots together with the movable scalpel 321. The upper receiving member 324b is a substantially L-shaped member positioned on the upper surface of the capturing lever 305, with the shorter portion of the L-shape connected to the pivot portion 306 by key engagement, and the longer portion of the L-shape positioned opposite the upper capturing member 324a. As a result, when the upper capturing member 324a rotates counterclockwise together with the capturing lever 305 and the movable scalpel 321, the upstream portion of the string-like material L can be gripped between the capturing member 324a and the receiving member 324b.

[0071] The second gripping portion 325, which grips the downstream portion of the string-like material, is positioned on the lower side of the base portion 212 and, similar to the above, consists of a lower capturing member 325a and a lower receiving member 325b, but these are not shown in Figure 17 and are therefore shown in Figure 18. The lower capturing member 325a is configured to pivot around the pivot portion 306 in accordance with the movement of the capturing lever 305, and is configured so that when the capturing lever 305 rotates counterclockwise, the downstream portion of the string-like material L can be gripped between the lower capturing member 325a and the lower receiving member 325b.

[0072] The heating element 211, made of an electric heating wire such as a nichrome wire, is fixed in a horizontal position on the base portion 212. For example, the base portion 212 has a curved opening 307, over which the linear heating element 211 is stretched horizontally in the front-to-back direction. The upstream and downstream portions of the string-like material L, gripped by the first and second gripping portions 324 and 325, pass through the opening 307, allowing their cut surfaces to come into contact with the heating element 211.

[0073] Figure 18 is an exploded perspective view of the main part of the cutting unit 210. The fixing member 312 of the gripping portion 310 is fixed to the upper surface of the tip portion of the base portion 212 by a screw 312a, and further back, the fixing female 322 is fixed to the upper surface of the base portion 212, straddling the opening 307. The heating member 211 is positioned to the right of the fixing female 322, and the heating member 211 is fixed to the upper surface of the base portion 212, straddling the opening 307. That is, the heating member 211 is positioned to the right of the fixing female 322, somewhat away from it.

[0074] A movable female slit 321 is screwed to the lower surface (back) of the capture lever 305, and the capture lever 305 is placed so that the movable female slit 321 is in contact with the fixed female slit 322, and an upper receiving member 324b is placed on top of the capture lever 305. The capture lever 305, the movable female slit 321, and the fixed female slit 322 are provided with holes through which a pivot portion 306 passes. This allows the capture lever 305 and the movable female slit 321 to pivot around the pivot portion 306. The upper receiving member 324b is key-engaged to the upper part 306a of the pivot portion 306 via a keyhole 324c, and is able to rotate together with the pivot portion 306. The pivot portion 306, which has passed through the capture lever 305, the movable female slit 321, and the fixed female slit 322, passes through the opening 307 and reaches the lower side of the base portion 212.

[0075] A guide lever 326 is positioned below the base portion 212. The guide lever 326 has a hole 326a through which the pivot portion 306 passes, and can pivot around the pivot portion 306. The guide lever 326 is connected to the upper capture lever 305 via a spacer 327 and fixed to the capture lever 305 by a screw 326b. As a result, the guide lever 326 pivots together with the capture lever 305 around the pivot portion 306. The lower capture member 325a of the second gripping portion 325 is fixed to the guide lever 326, and a guide edge portion 326c is formed thereon, which has a wave-like recess shape suitable for guiding the downstream portion of the string-like material toward the lower capture member 325a.

[0076] A swinging lever 328 is positioned below the guide lever 326. The swinging lever 328 engages with the lower part 306b of the pivot 306 via a keyhole 328a located in its middle position, allowing it to rotate together with the pivot 306. The lower receiving member 325b of the second gripping part 325 is fixed to the upper surface of the front portion of the swinging lever 328. In this swinging lever 328, the lower receiving member 325b is positioned at approximately the same height as the lower capturing member 325a positioned on the guide lever 326. As a result, when the lower capturing member 325a rotates counterclockwise together with the capturing lever 305, the lower capturing member 325a approaches the lower receiving member 325b, allowing the downstream portion of the string-like material L to be gripped between the capturing member 325a and the receiving member 325b.

[0077] One end of a tension spring 329 is attached to the rear portion of the oscillating lever 328, and the other end of the tension spring 329 is fixed to an appropriate location on the back surface of the base portion 212. In addition, an opening 212a is provided in a predetermined location on the base portion 212, extending over an appropriate range to allow the tension spring 329 to enter. The tension spring 329 is biased in the contraction direction, so in the unloaded state it is contracted, and in that state the oscillating lever 328 is approximately parallel to the length direction of the heating member 211. When a load is applied that rotates the oscillating lever 328 counterclockwise, the tension spring 329 extends, and the oscillating lever 328 can continue to rotate counterclockwise. When the counterclockwise load on the oscillating lever 328 is removed, the tension spring 329 returns to its contracted state, and the oscillating lever 328 rotates clockwise and returns to its original state (neutral state).

[0078] The upper receiving member 324b, the fixed blade 322, and the lower receiving member 325b are arranged to substantially overlap in a plan view when in the neutral position. In contrast, the heating member 211 is positioned to the right of these, somewhat separated from them in a plan view. Therefore, when the capture lever 305 is rotated counterclockwise to cut the string-like material L, as described above, the movable blade 321 approaches the fixed blade 322, and the respective capture members 324a and 325a of the first and second gripping parts 324 and 325 approach the respective receiving members 324b and 325b, and the string-like material L is cut almost simultaneously with the first and second gripping parts 324 and 325 gripping the string-like material L. When the capture lever 305 is continuously rotated counterclockwise to bring the upper and lower cut surfaces of the cut string-like material L into contact with the heating member 211, a load is applied that causes the oscillating lever 328 to rotate counterclockwise, and the tension spring 329 stretches. In this way, each cut surface of the cut string-like material L approaches the heating member 211 and comes into contact with it, causing it to be heated and melted. Once each cut surface is in contact with the heating member 211, the linear rod 232 of the air cylinder 231 is extended, and the capture lever 305 is rotated clockwise. This releases the counterclockwise load on the oscillating lever 328, the tension spring 329 returns to its contracted state, and the oscillating lever 328 (and the lower receiving member 325b) rotates clockwise and returns to its original state (neutral state). As the oscillating lever 328 rotates clockwise, the pivot 306, which is key-engaged to it, also rotates clockwise, and the upper receiving member 324b, which is key-engaged to it, also rotates clockwise, returning them to their original state (neutral state). As described above,

[0079] <Cutting and Heat Melting Operation> Next, referring to Figure 19 in addition to the figures described above, the cutting and heat melting operation performed by the cutting unit 210 at the end of sewing the string-like material L will be explained. In order to cut the string-like material, the lifting mechanism (moving device) 240 is driven to lower the cutting unit 210, as described above, and the material cutting device 200 is set to a cutting position similar to the state shown in Figure 13. As the cutting unit 210 descends, the movable scalpel 321 of the cutting device 320 and the respective capturing members 324a and 325a of the gripping parts 324 and 325 are kept open as shown in Figure 17.

[0080] When the cutting unit 210 reaches the cutting position, the string-like material L, which extends from the tip of one guide cylinder 61a corresponding to the needle source position and is connected to the final needle drop point below, is positioned between the open movable blade 321 and the fixed blade 322 of the cutting device 320, and between the respective capturing members 324a, 325a and receiving members 324b, 325b of the respective gripping parts 324, 325. Figure 19 is a schematic front view illustrating the operation of the main parts of the cutting unit 210 in several steps in order to explain the cutting and heat melting operations performed by the cutting unit 210 at the cutting position.

[0081] Figure 19(a) shows the cutting unit 210 reaching the cutting position with the movable scalpel 321 of the cutting device 320 in the open position. In this state, the string-like material L extending from the tip of the guide cylinder 61a enters the space between the open movable scalpel 321 and the fixed scalpel 322, and the space between the respective capturing members 324a, 325a and the respective receiving members 324b, 325b of the respective gripping parts 324, 325.

[0082] When the cutting unit 320 reaches the cutting position as shown in Figure 19(a), the descent by the lifting mechanism (moving device) 240 is stopped. Next, the linear rod 232 of the air cylinder 231 is retracted, and the capture lever 305 is rotated counterclockwise. At this time, the guide lever 326, which is located below the base portion 212, is also rotated counterclockwise. As a result, the movable blade 321 of the cutting device 320 closes toward the fixed blade 322, and the respective capture members 324a and 325a of the first and second gripping portions 324 and 325 close toward the corresponding receiving members 324b and 325b. In the process of these closing, the string-like material L, which extends from the tip of a guide cylinder 61a associated with the needle source position and is connected to the final needle drop point below, is appropriately guided by the guide edge portion 326c of the guide lever 326 (see Figure 18), and can be securely gripped by the respective gripping portions 324 and 325.

[0083] Figure 19(b) shows the state in which the movable scalpel 321 holds the string-like material L between itself and the fixed scalpel 322, and almost simultaneously shows the state in which the capturing members 324a and 325a of the respective gripping parts 324 and 325 are gripping the upstream and downstream portions of the string-like material L between themselves and the corresponding receiving members 324b and 325b. The linear rod 232 of the air cylinder 231 is still in the process of being retracted.

[0084] As the linear rod 232 of the air cylinder 231 contracts further from the state shown in Figure 19(b), the capture lever 305 and the guide lever 326 rotate further counterclockwise, causing the movable blade 321 to pass through the fixed blade 322 and the string-like material L to be cut. At the same time, the upper capture member 324a grips the upstream portion of the cut string-like material L between itself and the upper receiving member 324b, and the upper receiving member 324b is rotated counterclockwise. This maintains the state in which the upper capture member 324a grips the upstream portion of the cut string-like material L between itself and the upper receiving member 324b, and as they rotate further counterclockwise, the cut surface of the upstream portion of the string-like material L approaches and comes into contact with the heating member 211. Similarly, with the lower capturing member 325a gripping the downstream portion of the cut string-like material L between itself and the lower receiving member 325b, the lower receiving member 325b is rotated counterclockwise (see Figure 18). This maintains the state in which the lower capturing member 325a grips the downstream portion of the cut string-like material L between itself and the lower receiving member 325b, and as they are further rotated counterclockwise, the cut surface of the downstream portion of the string-like material L approaches and comes into contact with the heating member 323. When the lower receiving member 325b is rotated counterclockwise, the swing lever 328 is also rotated counterclockwise, and as described above, the tension spring 329 is extended.

[0085] Figure 19(c) shows the state in which the upstream and downstream portions of the string-like material L, gripped by the respective gripping parts 324 and 325, are in contact with the heating member 211. From this state, the capture lever 305 and the guide lever 326 rotate further counterclockwise, and as the upstream and downstream portions of the gripped string-like material L pass by the heating member 211 while in contact with it and reach its right side, the contraction movement of the air cylinder 231 ends, and the rotation of the capture lever 305 and the guide lever 326 stops. In this way, the upstream and downstream cut surfaces of the cut string-like material L, gripped by the respective gripping parts 324 and 325, are heated and melted by the heating member 211 as they pass by the heating member 323 while in contact with it.

[0086] Subsequently, the linear rod 232 of the air cylinder 231 is quickly extended, and the capture lever 305 and the guide lever 326 are rotated clockwise. As the capture lever 305 and the guide lever 326 rotate clockwise, the counterclockwise load on the swing lever 328 is released, the tension spring 329 returns to its retracted position, and the swing lever 328 also rotates clockwise and returns to its original state (neutral state). At the same time, the pivot part 306 rotates clockwise due to key engagement of the lower part 306b of the pivot part 306 via the key hole 328a of the swing lever 328, and the upper receiving member 324b also rotates clockwise due to key engagement of the upper part 306a of the pivot part 306 via the key hole 324c of the upper receiving member 324b, returning to its original state (neutral state).

[0087] As the capture lever 305 and the guide lever 326 rotate further clockwise, the gripping portions 324 and 325 of the upstream and downstream portions of the cut string-like material L are released. This state is shown in Figure 19(d). As a result, the upstream portion of the string-like material remaining on the side of the guide cylinder 61a hangs down appropriately from the tip of the guide cylinder 61a. On the other hand, the downstream portion of the string-like material connected to the final needle drop point falls freely. Here, each cut surface of the cut string-like material L is melted by heat, and the fibers of the string-like material L that have melted due to the heat cool and harden after cutting, so that the cut ends do not fray.

[0088] Once the air cylinder 231 has finished retracting, the linear rod 232 of the air cylinder 231 is extended again. This causes the capture lever 305 to rotate counterclockwise, and the capture members 324a and 325a of the first and second gripping parts 324 and 325 close toward the corresponding receiving members 324b and 325b. As they close, the upstream portion of the string-like material L remaining on the guide cylinder 61a side is re-gripped between the capture member 324a of the first gripping part 324 and the receiving member 324b. This state is shown in Figure 19(e).

[0089] After cutting and thermally melting the string-like material L in this manner, the material guide device 6 is rotated back to its predetermined position at the front (0 degrees) as described above. This sets the holding member 101 of the material holding mechanism 100 to its predetermined position at the rear (180 degrees) (a position on the lifting trajectory of the cutting unit 210). In this state, the lifting mechanism (moving device) 240 is driven in the manner described above to raise the cutting unit 210. During this raising process, the string-like material L, which extends from the guide cylinder 61a of the material guide device 6 and is gripped by the first gripping part 324, becomes capable of being held by the holding member 101 of the material holding mechanism 100. At an appropriate point after the string-like material L is capable of being held by the holding member 101 of the material holding mechanism 100, the air cylinder 231 is extended in the manner described above. As a result, the capturing member 324a of the first gripping part 324 opens, releasing the grip of the string-like material L by the first gripping part 324, and the released string-like material L is held by the holding member 101 of the material holding mechanism 100. Finally, when the cutting unit 210 rises to the retracted position, the series of cutting and heat melting operations is completed.

[0090] In the embodiments described above, the material supply device 1 for supplying the string-like material is positioned above the sewing head H, and a large bobbin 21 can be used. However, the invention is not limited to this configuration, and the material cutting device 200 according to the present invention can also be applied to a configuration in which a small bobbin on which the string-like material is wound is positioned around the needle bar, and the string-like material is supplied to the needle base while being rotated appropriately around the needle bar axis.

[0091] Furthermore, in the above embodiment, the material guiding device 6 for guiding the string-like material to the needle base position includes a plurality of guide tubes (guide members) 61a, and is configured so that one of the guide tubes (guide members) 61a can be selected. However, the material cutting device 200 according to the present invention can also be applied to embodiments in which the material guiding device 6 includes only one guide tube (guide member) 61a. When applying the material cutting device 200 according to the present invention to embodiments in which only one guide tube (guide member) 61a is included, the material holding mechanism 100 may be omitted, and the gripping member 220 may remain gripping the string-like material L in the retracted position without releasing the grip of the gripping member 220 after the string-like material has been heat-cut (that is, the gripping member 220 may also function as a holding member).

[0092] Furthermore, in the above embodiment, the material guide device 6 (supply side of the string-like material) for guiding the string-like material to the needle base position is configured to swing in a staggered pattern. However, the material cutting device according to the present invention can be applied regardless of the material guide means used on the supply side of the string-like material.

Claims

1. A material cutting device for a sewing machine capable of sewing a string-like material to a workpiece, comprising a cutting unit for cutting the string-like material connected to the workpiece, wherein the cutting unit includes a heating member for heat-melting the cut surface of the string-like material.

2. The material cutting device for a sewing machine according to claim 1, wherein the heating member is a heated cutting member, and the cutting unit further includes a gripping member for gripping a string-like material connected to the workpiece to be sewn, and an operating device that brings the string-like material gripped by the gripping member into contact with the cutting member, thereby causing the string-like material to be heat-melted and cut by the cutting member.

3. The material cutting device for a sewing machine according to claim 2, wherein the gripping member is arranged to grip the string-like material upstream of the cutting position by the cutting member.

4. The material cutting device for a sewing machine according to claim 2, wherein the operating device is configured to bring the string-like material into contact with the cutting member by rotating the gripping member relative to the cutting member while gripping the string-like material.

5. A material cutting device for a sewing machine according to any one of claims 2 to 4, further comprising a guiding member positioned downstream of the gripping position by the gripping member, and configured to contact the string-like material gripped by the gripping member downstream of the gripping position and guide the string-like material toward the cutting member.

6. The material cutting device in a sewing machine according to claim 5, wherein the guiding member is configured to move in conjunction with the gripping member.

7. A material cutting device for a sewing machine according to claim 2, further comprising a guiding member positioned downstream of the gripping position by the gripping member, and configured to contact the string-like material gripped by the gripping member downstream of the gripping position and guide the string-like material toward the cutting member.

8. The gripping member comprises a first member and a second member, and is configured to grip the string-like material by introducing the string-like material between the first member and the second member with the space between them open, and then closing the space between the first member and the second member, and the operating device is configured to give the gripping member a movement to close the space between the first member and the second member, and then bring the string-like material gripped by the gripping member into contact with the cutting member, the material cutting device in a sewing machine according to any one of claims 2, 3, 4, and 7.

9. The material cutting device for a sewing machine according to claim 8, wherein the actuator is configured to provide the first member with a movement to open and close the space between the first member and the second member, and to provide the first member with a movement to bring the string-like material into contact with the cutting member, the second member is spring-biased in the opposite direction to the movement of the first member to bring the string-like material into contact with the cutting member, moves together with the first member against the spring force in response to the movement of the first member to bring the string-like material into contact with the cutting member, and is configured to be returned by the spring force when the first member moves in the opposite direction.

10. A material cutting device for a sewing machine according to any one of claims 2, 3, 4, and 7, further comprising a moving mechanism that integrally moves the gripping member, cutting member, and operating device between a cutting position near the needle base and a retracted position away from the needle base, wherein the gripping member grips the sewn-on string-like material at the cutting position.

11. A material cutting device for a sewing machine according to any one of claims 2, 3, 4, and 7, further comprising a holding member for holding the cut string-like material gripped by the gripping member, wherein the gripping member releases its grip on the string-like material when the holding member holds the cut string-like material.

12. The sewing machine has a plurality of guide members for guiding a plurality of string-like materials to the vicinity of the needle base position, and each guide member is provided with a holding member corresponding to each guide member for holding each of the string-like materials guided by each guide member, the material cutting device in a sewing machine according to claim 11.

13. The material cutting device for a sewing machine according to claim 1, wherein the cutting unit includes a cutting device for cutting a string-like material connected to the workpiece, and the heating member is configured to heat-melt the cut surface of the string-like material cut by the cutting device.

14. The material cutting device for a sewing machine according to claim 13, wherein the cutting unit further includes a gripping portion for gripping the cut string-like material, and is configured to heat-melt the cut surface of the string-like material by bringing it into contact with the heating member while the string-like material cut by the cutting device is gripped by the gripping portion.

15. The material cutting device for a sewing machine according to claim 14, wherein the gripping portion is configured to grip the upstream portion and the downstream portion of the cut string-like material, respectively.

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