Guide device for string-like material in sewing machine

Abstract

The objective of the present invention is to provide a slim and simple zig-zag swing structure that eliminates bulkiness. A guide tip part (26) that guides a string-like material T to a needle base position is held at a lower portion of a support (102). A slide part (101) is secured to one side of the support (102), and said slide part (101) can move horizontally by engaging a horizontal rail (100) secured to a lateral surface of a cloth presser (9). The support (102) has an engaging part (110) on the opposite side from the slide part (101). A pivot lever (drive member) (21) for zig-zag swinging of the string-like material (T) has a cam groove (21b) (engagement structure) so that the support (102) is made to reciprocate in the horizontal direction while said support is an engaged state, via said engaging part (110), that allows for movement up and down. Pivoting the pivot lever in order to perform zig-zag stitching causes the support to reciprocate in the horizontal direction via the cam groove and the engaging part. At the same time, the support moves up and down with the up-and-down motion of the cloth presser during the stitching operation.

Description

Guiding device for string-like material in sewing machine

[0001] The present invention is applicable to a sewing machine capable of zigzag stitching a string-like material such as tape, cord or heater wire onto fabric, and relates to a guide device for guiding the string-like material.

[0002] Sewing machines capable of performing a so-called zigzag stitch, in which a string-like material such as tape or cord is fed in a zigzag (back-and-forth or swinging) motion relative to a needle base and sewn onto a fabric (a sewing object), are known. Such sewing machines typically include a needle bar with a sewing needle at its lower end that is driven up and down, a presser foot that moves up and down at a predetermined timing synchronized with the up and down movement of the needle bar to press down on the fabric, and a guide device for guiding the string-like material to the needle base. The guide device includes a rotor that is assembled concentrically with the needle bar and is freely rotatable about its axis, and is configured to calculate the sewing direction relative to the fabric based on predetermined sewing data in conjunction with the rotor and control the direction of the rotor so that the tip of the guide that guides the string-like material to the needle base is always positioned ahead in the sewing direction. The guide device also includes a zigzag mechanism that causes the tip of the guide to reciprocate back and forth or swing to perform a zigzag stitch.

[0003] Japanese Patent Application Laid-Open No. 2003-144993 discloses a guide device including such a zigzag mechanism. The zigzag mechanism shown therein is configured such that one side of a support member consisting of a horizontally arranged rectangular frame is fixed to a presser foot, a swing lever that applies a driving force for zigzag stitching is disposed so as to penetrate the rectangular frame of the support member, and a mechanism for transmitting the swinging motion of the swing lever to the tip of the guide is provided on the other side of the support member, resulting in an overall bulky structure.

[0004] Japanese Patent Application Laid-Open No. 2010-220780

[0005] Generally, in sewing machines (e.g., embroidery machines) that sew any pattern by driving a holding frame that holds fabric (the sewing object), sewing cannot be performed in areas where devices and equipment installed around the sewing needle of the sewing machine head interfere with the frame edges, resulting in a certain range inside each frame edge of the holding frame being an unsewable area (dead space). In a zigzag mechanism such as the guide device disclosed in Patent Document 1, which has a bulky overall structure, this unsewable area (dead space) is created in an excess area due to the bulkiness, thereby reducing the sewable area of ​​the fabric held by the holding frame. Furthermore, a bulky zigzag mechanism also has the problem of being prone to loosening of screws in its components due to mechanical vibrations during sewing.

[0006] The present invention has been made in view of the above points, and aims to provide a guide device for a string-like material that is slim and has a simple configuration without being bulky.

[0007] The guide device of the present invention is a guide device for guiding a string-like material to the needle base position of a sewing needle in a sewing machine capable of zigzag stitching a string-like material on a workpiece, and comprises: a horizontally long rail configured to be fixed to the side of the cloth presser foot of the sewing machine; a support having a slide portion on one side that engages with the rail and is movable laterally, and an engagement portion on the opposite side to the slide portion; a drive member that moves the support back and forth laterally while engaging the support so that it can move up and down via the engagement portion; and a guide tip portion that is held by the support and moves together with the support; the string-like material is passed through the guide tip portion and guided to the needle base position, and when zigzag stitching is performed, the support is moved back and forth laterally by the drive member.

[0008] According to the present invention, the support member that holds the guide tip has a sliding portion on one side and an engaging portion on the other side, and engages with a rail fixed to the side of the presser foot via the sliding portion on the one side, and with a drive member that applies driving force for zigzag stitching via the engaging portion on the other side. This allows the zigzag-related mechanism near the guide tip that guides the string-like material to the needle base position to be slimmed down in terms of the arrangement direction of these components (e.g., the front-to-rear direction of the sewing machine). Furthermore, since there is no rectangular frame support member as in the above-mentioned prior art, the extra bulkiness caused by a rectangular frame is eliminated in terms of the reciprocating direction of the support member (e.g., the lateral direction as viewed from the front of the sewing machine), resulting in a slimmed down structure. Furthermore, the number of main parts is simplified to just three: the rail on the presser foot, the support member that holds the guide tip, and the drive member. Therefore, it is possible to provide a guide device with a simple and slim overall configuration, which does not require a support member made of a rectangular frame as in the above-mentioned prior art, and which is less bulky. This makes it possible to suppress or reduce the occurrence of unsewable areas (dead space) near each frame side of the holding frame that holds the sewing object (fabric), thereby contributing to ensuring a wider sewing area, and is expected to reduce the incidence of loosening of screws in each component due to the weight reduction and reduction in the number of components.

[0009] 1 is a front view showing an embodiment of a sewing machine head capable of zigzag stitching to which a string-like material guiding device according to the present invention is applied. FIG. 2 is a left side view showing a part of the sewing machine head shown in FIG. 1 cut away. FIG. 3 is a left side view showing an enlarged view of the lower part of the sewing machine head shown in FIG. 1, showing a state in which the cloth presser body is in the process of moving up and down during sewing operation. FIG. 4 is a left side view showing an enlarged view of the lower part of the sewing machine head shown in FIG. 1, showing a state in which the cloth presser body has risen to a standby position when sewing operation has stopped. FIG. 5 is a front view corresponding to FIG. 4, showing a state in which the cloth presser body has risen to the standby position.

[0010] FIG. 1 is a front view of an embodiment of a sewing machine head H capable of producing zigzag stitches and incorporating a string-like material guiding device according to the present invention. FIG. 2 is a side view of the sewing machine head H shown in FIG. 1, with a portion cut away. Note that a bobbin 33 around which a string-like material T is wound, shown in FIG. 2, is omitted from FIG. 1 for clarity. The sewing machine head H is provided with a needle bar 2 whose axial direction extends vertically. The needle bar 2 is driven to reciprocate vertically in response to the rotation of a sewing machine main shaft 1. A sewing needle 3 is attached to the lower end of the needle bar 2. A support tube 4 is attached to the outer periphery of the needle bar 2. The support tube 4 is guided by the inner circumferential surface of a fixed sleeve 5 fixed to the lower part of the sewing machine head H, allowing it to move up and down relative to the needle bar 2 and to rotate about the axis of the needle bar 2. An engagement ring 6 is fixed to the outer periphery of the upper end of the support tube 4. A drive arm 8, which moves up and down when driven by a motor 7, engages with the engagement ring 6.

[0011] As shown in FIG. 2 , a presser foot 9 is fixed to the lower end of the support cylinder 4. The presser foot 9 shown in this embodiment is a known type known as a "nipple" and includes a pair of legs (or side portions) 9a, 9b and a tapered tubular tip portion 9c formed by connecting the lower ends of the legs. The needle 3 passes through the space between the legs 9a, 9b, and the tip portion 9c has an opening for passing the needle 3. The presser foot 9 is moved up and down via the drive arm 8 and the support cylinder 4 in response to the drive of the motor 7, thereby performing a known presser function by moving up and down at a predetermined timing synchronized with the up and down movement of the needle bar 2. A key groove 9d extending vertically is formed in the side of the presser foot 9 (the leg portion 9a on the back side when viewed from the front). This key groove 9d is adapted to engage with a key member 17 attached to the lower end of the rotary cylinder 11, which will be described later. Due to the engagement of the key member 17 with the key groove 9d, when the presser foot 9 moves up and down in accordance with the up and down movement of the support tube 4, the rotary tube 11 does not move up and down, but when the rotary tube 11 rotates, the presser foot 9 rotates together with the rotary tube 11 about the axis of the needle bar 2. In this way, the presser foot 9 is controlled to move up and down via the support tube 4 in response to the drive of the motor 7, and its rotation is controlled via the rotary tube 11 in response to the drive of the motor 13, which will be described later. Reference numeral 37 denotes a well-known needle plate.

[0012] The sewing machine head H is provided with a guide device 10 for guiding the string-like material T to the needle base position of the sewing needle 3. The guide device 10 is configured to perform two types of guide functions: (1) a function for guiding the string-like material T so that the guide direction is appropriate in accordance with the movement direction of the sewn object (fabric) based on the sewing data (or embroidery data), that is, a function for guiding the string-like material T so that it is directed in the sewing progress direction (hereinafter referred to as the "normal guide function" for convenience), and (2) a function for guiding the string-like material T so that it is staggered in order to sew the string-like material T onto the sewn object (fabric) with a staggered stitch (zigzag stitch) (hereinafter referred to as the "staggered stitch function" for convenience).

[0013] First, the configuration related to the "normal guide function" will be described. As shown in FIG. 2, a rotatable cylinder 11 is attached to the outer periphery of the fixed sleeve 5. The rotatable cylinder 11 is attached concentrically with the needle bar 2 and is only capable of rotation about the axis of the needle bar 2. A timing pulley 12 is provided on the outer periphery of the upper end of the rotatable cylinder 11, and a timing belt 16 is wound between the timing pulley 12 and a drive pulley 15 fixed to a rotary shaft 14 of a motor 13. As a result, when the motor 13 is driven and the drive pulley 15 rotates, the rotatable cylinder 11 rotates via the timing belt 16 and the timing pulley 12. The key member 17 is fixed to the lower end of the rotatable cylinder 11 and engages with the key groove 9d of the presser foot 9 as described above. Meanwhile, a bobbin bracket 32 ​​is fixed to the outer periphery of the rotatable cylinder 11 via a bracket 20 and an arm member 31. A bobbin 33 around which a string-like material T is wound is rotatably supported by the bobbin bracket 32. The string-like material T unwound from the bobbin 33 is passed through the guide tip 26 held by the support 102 as will be described later, and guided to the needle base position.

[0014] Next, a configuration related to the "zigzag function" will be described. As shown in FIG. 2, an interlocking member 18 is fitted to the outer periphery of the rotating barrel 11 so as to be movable up and down and rotatable. As shown in FIG. 1, a connecting piece 19 is fixed to the interlocking member 18, and the connecting piece 19 engages with an engagement groove 11a formed on the outer periphery of the rotating barrel 11. As a result, the interlocking member 18 rotates integrally with the rotating barrel 11 as the rotating barrel 11 rotates. A swing lever 21 (drive member) is attached to the rotating barrel 11 via a bracket 20. The swing lever 21 is attached to the outer surface of the bracket 20 so as to be swingable left and right (laterally) around a lever pin 22 attached to the outer surface of the bracket 20 as a fulcrum. A cam groove (in other words, a groove or opening) 21b is formed in the vertical swing piece extending downward from the fulcrum. This cam groove (groove or opening) 21b functions as an engagement structure that engages with an engagement portion 110 of the support body 102 (described later) so as to be movable up and down. On the other hand, a roller 23 is attached to the tip of an arm 21 a extending laterally from the fulcrum (lever pin 22 ), and the roller 23 is engaged with a connecting groove 19 a of the connecting piece 19 .

[0015] As shown in FIG. 1 , a guide shaft 34 with a vertical (up-down) axis is fixed adjacent to the needle bar 2. A lifting member 35 is attached to the guide shaft 34. The lifting member 35 is guided by the guide shaft 34 and moves up and down along its axial direction by the driving force generated by the rotation of a zigzag motor 36 transmitted via a drive transmission mechanism (not shown). A fork portion 35a protruding substantially horizontally toward the needle bar 2 is formed on the lifting member 35, and this fork portion 35a engages with a groove 18a formed on the outer periphery of the interlocking member 18. Therefore, when the interlocking member 18 and the connecting piece 19 move up and down due to the up-and-down movement of the lifting member 35, the up-and-down movement of the connecting piece 19 is transmitted to the arm 21a of the swing lever 21 via the interlocking groove 19a and the roller 23 and converted into swing of the swing lever 21 via the fulcrum (lever pin 22). The swinging movement of the swing lever 21 serves as a driving source for zigzagging the string-like material T threaded through the guide tip portion 26 .

[0016] A horizontally elongated rail 100 is fixed to the side of the presser foot 9 opposite the key groove 9a (the leg 9b on the front side when viewed from the front) via an appropriate connecting member 120. A slide 101, which engages with the rail 100 and slides laterally (horizontally), is fixed to one side of a support 102. The support 102 is a vertically elongated member as shown in FIG. 1, and is configured to hold the guide tip 26 at its lower end via an appropriate connecting member 103. For example, the support 102 may have a simple shape such as a plate. The connecting member 103 may be appropriately bent as shown in FIG. 2 (or enlarged in FIG. 3) to provide an appropriate downward angle to the string-like material T extending from the guide tip 26. An engaging member 110 is provided on the other side of the support 102 (i.e., the side opposite the slide 101). The support body 102 is configured to be engaged with the swing lever 21 (driving member) so as to be movable up and down via the engaging portion 110. As an example, the engaging portion 110 of the support body 102 is formed of a roller-shaped protrusion that engages with the cam groove (groove or opening) 21b of the swing lever 21 (driving member) so as to be movable up and down.

[0017] With this configuration, the support 102 moves up and down through the engagement between the rail 100 and the slide portion 101 as the presser foot 9 moves up and down. At this time, the engaging portion 110 also moves up and down along with the support 102. However, because the engaging portion 110 moves up and down through the cam groove 21b, the up and down movement is not transmitted to the swing lever 21. FIG. 3 shows the guide device 10 in the sewing position, i.e., the presser foot 9 moving up and down during sewing. FIG. 4 shows the guide device 10 raised to the retracted position, i.e., the presser foot 9 raised to the standby position when sewing is stopped. FIG. 5 is a front view of the presser foot 9 raised to the standby position. As is well known, during sewing, the presser foot 9 moves up and down between predetermined top and bottom dead points. The height of the bottom dead point of the presser foot 9 can be variably adjusted by controlling the motor 7 depending on the thickness of the fabric being sewn and the type of string-like material T. As the height of the bottom dead point of the work presser foot 9 is changed, the height position of the bottom dead point of the guide tip 26 can also be automatically changed.

[0018] On the other hand, the lateral swinging motion of the swing lever 21 is transmitted to the support 102 as a lateral swinging motion due to the engagement between the cam groove 21b and the engagement portion 110. At this time, the support 102 makes a linear reciprocating motion in the lateral direction along the rail 100 via the slide portion 101. This linear reciprocating motion of the support 102 causes the string-like material T threaded through the guide tip portion 26 to oscillate in a zigzag manner.

[0019] Next, we will explain how to sew a string-like material T onto a workpiece by lockstitching using the sewing machine head H configured as described above. First, a bobbin 33 around which the string-like material T is wound is set in the bobbin bracket 32. The string-like material T is then unwound from the bobbin 33 and threaded through the guide tip 26 to the needle base (needle drop position) of the sewing needle 3. In this state, the workpiece (not shown) is controlled to move in the X and Y directions based on sewing data (or embroidery data) corresponding to a predetermined stitch pattern, and the needle bar 2 is driven up and down to perform a well-known lockstitch using the functions of the sewing needle 3 and the shuttle (not shown). During this process, the drive lever 21 is driven by the zigzag motor 36 to swing back and forth from the neutral position shown in FIG. 1 to the left and right. As a result, the string-like material T, which is guided by the guide tip 26 to the needle drop position of the sewing needle 3, is swung back and forth to the left and right of the needle drop position, for example, with each reciprocation of the needle bar 2 (each stitch). As a result, the string-like material T is successively sewn onto the workpiece by a zigzag stitch.

[0020] At this time, as the rotary cylinder 11 is rotated by the drive of the motor 13, the lever pin 22 is controlled so as to always be positioned in front of the sewing machine head H in the relative direction of travel based on the movement of the workpiece. The presser foot 9 is driven by the motor 7 to move up and down between predetermined top and bottom dead points at predetermined timing relative to the up and down movement of the needle bar 2, thereby fulfilling its function as a presser foot, and the guide tip 26 also moves up and down together with the presser foot 9. Eventually, when sewing of the string-like material T is completed, the motor 7 drives the presser foot 9 and the guiding device 10 (the guide tip 26) to the retracted position shown in Figures 4 and 5.

[0021] As described above, and as can be seen particularly from Figures 2 to 4, the support body 102 that holds the guide tip 26 has a slide portion 101 on one side and an engaging portion 110 on the opposite side, and engages with the rail 100 fixed to the side of the presser foot 9 via the slide portion 101 on the one side, and engages with the drive lever (drive member) 21 that applies the driving force for zigzag stitching via the engaging portion 110 on the opposite side, thus having an extremely simple and compact structure. As a result, the zigzag-related mechanism in the vicinity of the guide tip 26 that guides the string-like material T to the needle base position can be provided with a slim structure in terms of the arrangement direction of these components 100, 102 (101, 110), 21, i.e., the front-to-rear direction as viewed from the front of the sewing machine (the left-to-right direction in Figures 2 to 4). 1 and 5, the size occupied by the zigzag-oscillating mechanism near the guide tip 26 in the reciprocating direction of the support body 102, i.e., the lateral direction as viewed from the front of the sewing machine (left-right direction in FIGS. 1 and 5), is only the length of the rail 100, since there is no support member made of a rectangular frame as in the prior art, and in this respect, too, the structure is slim. Furthermore, the number of main parts is reduced to three: the rail 100 on the presser foot 9 side, the support body 102 holding the guide tip 26, and the drive lever (drive member) 21, resulting in a simplified structure. Therefore, a support member made of a rectangular frame as in the prior art is not necessary, and it is possible to provide a guide device 10 that is slim and has a simple structure overall, without being bulky. This makes it possible to suppress or reduce the occurrence of unsewable areas (dead space) near each frame edge of the holding frame (embroidery frame) that holds the sewing object (fabric), thereby contributing to ensuring a wider sewing area, and by reducing weight and the number of parts, the occurrence of loose screws in each component part, etc. can be reduced.

[0022] The structure for transmitting the swinging motion of the swing lever (driving member) 21 to the support 102 is not limited to the cam groove 21b and the roller-shaped protrusion engaging portion 110 shown in the above embodiment, and can be modified as appropriate. For example, the engaging portion 110 of the support 102 may be configured to be a vertically long block, and the cam groove 21b of the swing lever (driving member) 21 may be omitted, and instead a pair of rollers may be included that sandwich the block as the engaging portion 110 and engage with the block so that the block can move up and down. Even in such a modification, with the support 102 engaged with the swing lever (driving member) 21 so that the support 102 can move up and down, the support 102 can move back and forth laterally through the engagement between the pair of rollers and the vertically long block in response to the swing of the swing lever (driving member) 21.

[0023] Furthermore, the structure of the presser foot 9 is not limited to the "nipple" type shown in the above embodiment, but any other suitable structure may be adopted. The point is that the presser foot 9 only needs to have a structure to which a horizontally elongated rail 100 can be attached. In addition, the various components shown in the above embodiment can also be modified in various ways as required.

Claims

1. In a sewing machine capable of performing a zigzag stitch on a workpiece, a guiding device for guiding the string-like material to the needle base position of the sewing needle, a horizontally long rail configured to be fixed to the side surface of the presser foot of the sewing machine, a support having a slide portion engageable with the rail and movable in the horizontal direction on one side, and an engaging portion on the side opposite to the slide portion, a driving member for reciprocating the support in the horizontal direction in a state where the support is engaged with the engaging portion so as to be vertically movable through the engaging portion, a guide tip portion held by the support and moving together with the support, wherein the string-like material is guided to the needle base position through the guide tip portion, and the support is reciprocated in the horizontal direction by the driving member during a zigzag stitch.

2. The guiding device according to claim 1, wherein the driving member has a vertically long groove, and the engaging portion of the support includes a columnar protrusion that is vertically movably engaged with the vertically long groove, and the support is reciprocated in the horizontal direction through the engagement of the protrusion and the groove.

3. The guiding device according to claim 1, wherein the engaging portion of the support is composed of a vertically long block, and the driving member includes a pair of rollers that are vertically movably engaged with the block while sandwiching the block from the left and right, and the support is reciprocated in the horizontal direction through the engagement of the rollers and the block.

4. The guiding device according to any one of claims 1 to 3, wherein the support has a vertically long plate shape.

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