Needle bar driving device and eyelet buttonholing machine

Abstract

The invention provides a needle bar driving device, and relates to the technical field of sewing machinery, a needle bar is mounted on a driving arm, and the driving arm and the needle bar are relatively fixed on the axis of the needle bar through two check rings; the driving arm is provided with a notch used for containing the needle rod to rotate, the driving arm is provided with protruding blocks in an upward protruding mode and a downward protruding block in a downward protruding mode, the two check rings make contact with the arc-shaped faces of the protruding blocks respectively, and therefore different angles are allowed to be formed between the needle rod and the driving arm, and the needle rod conducts conical swing relative to the driving arm. During working, a driving arm of the up-down driving mechanism drives the needle rod to slide relative to the upper sleeve, and the swing driving mechanism drives the needle rod to perform conical swing by taking the upper sleeve as a rotation center, so that the needle rod simultaneously performs reciprocating up-down translational motion and conical swing; compared with a traditional cross universal joint structure, the structure is smaller in size, lighter in weight, smaller in motion inertia and capable of achieving higher motion speed.

Description

Technical Field

[0001] This invention relates to the field of sewing machinery technology, and more particularly to a needle bar drive device and a round-head buttonhole machine. Background Technology

[0002] Buttonhole machines are mainly used to process buttonholes in various garments. They are divided into flat-head buttonhole machines (straight buttonhole machines) and round-head buttonhole machines (phoenix buttonhole machines), and are further divided into those with and without finishing. They are a very important type of specialized equipment in garment machinery. Flat-head buttonhole machines are suitable for shirts and casual trousers, while round-head buttonhole machines are suitable for suits and jeans buttonholes.

[0003] The needle bar of a round-head buttonhole machine needs to swing left and right during the sewing process, and also needs to rotate in a circle (similar to the function of a universal joint), so that it can swing in any direction within a certain range.

[0004] When the sewing machine motor drives the spindle to rotate, the needle bar moves up and down through a crank transmission device consisting of crank rods that can be driven by the needle bar crank, while the needle swing mechanism moves, thereby forming a round-headed buttonhole stitch on the fabric placed on the feeding table.

[0005] Traditional round-head buttonhole machines have a complex structure for swinging and up-and-down movement, resulting in a large inertia that makes it difficult to achieve high-speed operation. Summary of the Invention

[0006] The core of this invention is to provide a needle bar driving device, which offers a novel structure for realizing reciprocating motion and conical oscillation. The structure is simpler, lighter, and reduces the moment of inertia to achieve higher motion speeds. The specific solution is as follows:

[0007] A needle bar drive device includes a housing, a needle bar, an up-and-down drive mechanism, and a swing drive mechanism;

[0008] A drive arm is mounted on the needle bar, and two retaining rings are fixedly mounted on the needle bar. The retaining rings fix the drive arm and the needle bar relative to each other on the axis of the needle bar. The drive arm has a notch for accommodating the rotation of the needle bar, and the drive arm has protrusions extending upward and downward respectively. The two retaining rings respectively cooperate with the arc-shaped surfaces of the protrusions so that the needle bar can swing conically relative to the drive arm.

[0009] The housing is provided with an upper sleeve for cooperating with the needle bar. The up-down driving mechanism enables the driving arm to drive the needle bar to slide relative to the upper sleeve. The swing driving mechanism drives the needle bar to swing in a conical motion around the upper sleeve as the rotation center.

[0010] Optionally, the drive arm is provided with a semi-enclosed notch, and the protrusion is located at the edge of the notch of the drive arm.

[0011] Optionally, the radial length of the protrusion is less than or equal to the wall thickness of the drive arm; the circumferential length of the protrusion is equal to the radial length of the protrusion.

[0012] Optionally, a washer is clamped between the retaining ring and the protrusion; the washer is provided with an arc-shaped groove for engaging with the arc-shaped surface of the protrusion.

[0013] Optionally, the side wall of the retaining ring is provided with a threaded hole for screwing in the tightening screw, the end of which can be pressed against the side wall of the needle bar to achieve tightening and fixation.

[0014] Optionally, the up-and-down drive mechanism includes a main drive shaft, a crank, and a connecting rod. The main drive shaft is used to drive the crank to rotate. A transmission pin is eccentrically provided on the crank. The transmission pin is rotatably connected to one end of the connecting rod, and the other end of the connecting rod is rotatably connected to the drive arm.

[0015] The housing is provided with a guide rail and a slider, the drive arm is hinged to the slider, and the slider can reciprocate along the length of the guide rail.

[0016] Optionally, the swing drive mechanism includes a transmission belt and a rotating block. The rotating block has an eccentrically arranged guide hole. The through direction of the guide hole is at an angle to the rotation axis of the rotating block. The needle bar is slidably inserted into the guide hole.

[0017] Optionally, the needle bar is provided with a flat rectangular section, which is used for sliding engagement with the rotating block.

[0018] Optionally, the upper sleeve includes an outer ring and an inner ring, the outer ring being fixedly mounted to the housing, and the inner ring being rotatably mounted to the outer ring;

[0019] The housing is provided with a recessed platform for accommodating and supporting the outer ring.

[0020] The present invention also provides a round-head buttonhole machine, including the needle bar drive device described in any of the above claims.

[0021] This invention provides a needle bar drive device. The needle bar is mounted on a drive arm, and the drive arm and the needle bar are fixed relative to each other on the axis of the needle bar by two retaining rings. The drive arm has a notch for accommodating the rotation of the needle bar, and the drive arm has protrusions extending upward and downward respectively. The two retaining rings contact the arc-shaped surfaces of the protrusions, thereby allowing different angles to be formed between the needle bar and the drive arm, so that the needle bar can swing conically relative to the drive arm. During operation, the up-and-down drive mechanism drives the drive arm to slide relative to the upper sleeve, and the swing drive mechanism drives the needle bar to swing conically with the upper sleeve as the center of rotation, so that the needle bar can simultaneously perform reciprocating up-and-down translational motion and conical swing. Compared with the traditional universal joint structure, this structure is smaller in size, lighter in weight, and has less moment of inertia, and can achieve higher movement speed. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is an isometric view of an assembly of a specific embodiment of the needle bar drive device of the present invention;

[0024] Figure 2 This is an exploded view of a specific embodiment of the needle bar driving device of the present invention;

[0025] Figure 3 This is a schematic diagram of a specific embodiment of the drive arm cooperating with the washer and retaining ring below.

[0026] The image includes:

[0027] 1. Housing, 11. Upper sleeve, 111. Outer ring, 112. Inner ring, 112. Guide rail, 12. Slider, 13. Needle bar, 2. Flat square section, 21. Up and down drive mechanism, 3. Main drive shaft, 31. Crank, 32. Transmission pin, 321. Connecting rod, 33. Swing drive mechanism, 4. Transmission belt, 41. Rotating block, 42. Drive arm, 5. Protrusion, 51. Arm fork structure, 52. Pin, 53. Retaining ring, 6. Washer, 61. Curved recess, 611. Threaded hole, 62. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solution of the present invention, the needle bar driving device and round-head buttonhole machine of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] This invention provides a needle bar driving device, including a housing 1, a needle bar 2, an up-and-down driving mechanism 3, and a swing driving mechanism 4; combined with Figure 1 As shown in the diagram, a schematic diagram of the needle bar drive device is presented. The housing 1 shown is a cut-out structure and not the complete housing structure. The specific structure of housing 1 can have different designs and is not limited to the form shown in the diagram. Housing 1 is the main supporting part of the entire needle bar drive device and can be composed of plates or rods. Other related structures are installed on housing 1.

[0030] A drive arm 5 is mounted on the needle bar 2. The needle bar 2 and the drive arm 5 can rotate relative to each other, but there is no relative displacement between them along the axial direction of the needle bar 2. Two retaining rings 6 are fixedly mounted on the needle bar 2. The two retaining rings 6 can be detachably or integrally fixed to the needle bar 2. There is no relative displacement or rotation between the retaining rings 6 and the needle bar 2. There is a certain gap between the two retaining rings 6 along the axial direction of the needle bar 2. The two retaining rings 6 are located above and below the drive arm 5, respectively. The upper retaining ring 6 presses on the upper part of the drive arm 5, and the lower retaining ring 6 presses on the lower part of the drive arm 5. The two retaining rings 6 clamp the drive arm 5 with each other along the axial direction. The two retaining rings 6 fix the drive arm 5 and the needle bar 2 relatively on the axial direction of the needle bar 2, keeping the drive arm 5 and the needle bar 2 in synchronous displacement along the axial direction of the needle bar 2; however, the needle bar 2 can oscillate conically relative to the drive arm 5.

[0031] The drive arm 5 has a notch for accommodating the rotation of the needle bar 2. This notch can be a complete closed annular notch or an incomplete open notch. Figure 2 As shown, the complete structure of the drive arm 5 is illustrated. Figure 2 The drive arm 5 shown here has a semi-circular open notch structure. The inner diameter of the notch is larger than the outer diameter of the needle bar 2. When the needle bar 2 swings relative to the drive arm 5, the notch creates enough space so that the drive arm 5 will not interfere with the needle bar 2.

[0032] The drive arm 5 has protrusions 51 extending upwards and downwards, that is, protrusions 51 are provided on the upper and lower surfaces of the drive arm 5, and the protrusions 51 protrude from the outer surface of the drive arm 5; combined with Figure 2 As shown, two protrusions 51 are respectively provided on the upper and lower sides of the drive arm 5, for a total of four protrusions 51. Of course, the number of protrusions 51 can also be arranged in other ways, and should not be limited to the form shown in the attached figure.

[0033] Two retaining rings 6 respectively mate with the arc-shaped surfaces of the protrusions 51. The retaining rings 6 can directly contact the surface of the protrusions 51, or other components can be provided between them to form an indirect mate. The protrusions 51 are provided with arc-shaped surfaces, and the retaining rings 6 can move spatially relative to the arc-shaped surfaces of the protrusions 51, so that the needle bar 2 can perform conical swing relative to the drive arm 5, and the center point of the conical swing coincides with the position of the upper sleeve 11.

[0034] The housing 1 is provided with an upper sleeve 11 for cooperating with the needle bar 2. The upper sleeve 11 is assembled on the housing 1 and limits the movement of the needle bar 2. The needle bar 2 can move along the axial direction relative to the upper sleeve 11 and can also swing relative to the upper sleeve 11. The needle bar 2 passes through the upper sleeve 11, and the part of the needle bar 2 above the upper sleeve 11 and the part below the upper sleeve 11 respectively perform conical swinging. Figure 2 As shown by the dotted line A, the position where the needle bar 2 coincides with the upper sleeve 11 does not move in the radial direction. The farther the needle bar 2 is from the upper sleeve 11, the greater the amplitude of the radial swing.

[0035] The up-down drive mechanism 3 can drive the arm 5 to slide the needle bar 2 relative to the upper sleeve 11. The swing drive mechanism 4 drives the needle bar 2 to make conical swing with the upper sleeve 11 as the rotation center. The needle bar 2 forms a superimposed motion state of reciprocating translation and conical swing.

[0036] The needle bar drive device provided by this invention mainly cooperates with the needle bar 2 through the drive arm 5, which can satisfy the superimposed motion of translation and conical oscillation of the needle bar 2. The drive arm 5 is an independent structure, which ultimately achieves matching with the needle bar 2 by relying on the protrusion 51 and its shape design. Compared with the traditional universal joint structure, which does not have the matching between multiple structures, this invention has the characteristics of smaller size, lighter weight, and smaller moment of inertia, and can achieve higher movement speed.

[0037] Based on the above solution, the drive arm 5 of the present invention is provided with a semi-enclosed notch, combined with Figure 3 As shown, the drive arm 5 includes a cylindrical main body structure, with a C-shaped open arm fork structure 52 at the end of the cylindrical main body. The arm fork structure 52 forms an open notch for accommodating the needle bar 2. A protrusion 51 is located at the edge of the notch in the drive arm 5, as shown... Figure 3 As shown, a total of four protrusions 51 are provided. Protrusions 51 are provided above and below the two ends of the arm fork structure 52. The two protrusions 51 on the upper edge are used to cooperate with the upper retaining ring 6, and the two protrusions 51 on the lower edge are used to cooperate with the lower retaining ring 6. Each protrusion 51 is provided with a curved surface, which can realize the swing of the retaining ring 6 relative to the drive arm 5.

[0038] Figure 3 The structure shown is a specific form. This invention does not exclude the provision of a completely closed annular structure for inserting the needle bar 2, in which case four protrusions 51 are also provided. Figure 3The open, arc-shaped notch design helps reduce weight and facilitates the assembly of the needle bar 2. If a closed ring structure were used, one end of the needle bar 2 would need to be inserted through the channel when installing it, making assembly more inconvenient; with the notch design, the needle bar 2 can be inserted horizontally, making assembly easier.

[0039] In one embodiment, the radial length of the protrusion 51 is less than or equal to the wall thickness of the drive arm 5, and the arm fork structure where the protrusion 51 is located adopts a semi-cylindrical shape and has a certain wall thickness. Figure 3 As shown, under normal circumstances, the radial length of the protrusion 51 is equal to the wall thickness of the semi-cylinder. The circumferential length of the protrusion 51 is equal to the radial length of the protrusion 51. The cross-section of the protrusion 51 is approximately square. It should be noted that the protrusion 51 itself has a certain curvature, which matches the inner and outer surfaces of the arm fork structure.

[0040] Combination Figure 2 As shown, a washer 61 is sandwiched between the retaining ring 6 and the protrusion 51. The washer 61 directly contacts the protrusion 51, and abuts against the arc-shaped raised surface of the protrusion 51. The washer 61 forms a gap between the protrusion 51 and the retaining ring 6. Figure 3 As shown, a through channel is provided in the center of the washer 61 and the retaining ring 6, which is used to insert the needle bar 2.

[0041] Combination Figure 3 As shown, a curved recess 611 is provided on the surface of the washer 61 that contacts the protrusion 51. The spherical surface of the protrusion 51 can be precisely embedded in the washer 61. The curved recess 611 of the washer 61 can form a smoother match with the protrusion 51, achieving a smoother swinging motion. The surfaces of the washer 61 and the retaining ring 6 that contact each other are flat, ensuring full contact and effective fit.

[0042] Combination Figure 3 As shown, the side wall of the retaining ring 6 is provided with a threaded hole 62 for screwing in a tightening screw. The end of the tightening screw (not shown in the figure) can be pressed against the side wall of the needle bar 2 to achieve a tight fixation. The tightening screw has an external thread, which is screwed into the threaded hole 62, so that the needle bar 2 and the retaining ring 6 can be fixedly assembled relative to each other. Multiple threaded holes 62 are provided on the side wall of the retaining ring 6, so only one tightening screw needs to be screwed in during use. It can be installed in any of the threaded holes 62, which is convenient for assembly in a confined space.

[0043] Combination Figure 1 , Figure 2As shown, the up-and-down driving mechanism 3 provided by the present invention includes a main drive shaft 31, a crank 32, and a connecting rod 33. One end of the main drive shaft 31 is connected to a rotary power device, such as a motor, and the other end is connected to the crank 32. When the main drive shaft 31 rotates, it drives the crank 32 to rotate, and the main drive shaft 31 and the crank 32 rotate synchronously. A transmission pin 321 is eccentrically arranged on the crank 32, and there is a radial distance between the crank shaft 32 and the transmission pin 321. When the crank 32 rotates, it drives the transmission pin 321 to perform a circular motion.

[0044] Transmission pin 321 is rotatably connected to one end of connecting rod 33, and the other end of connecting rod 33 is rotatably connected to drive arm 5, in combination. Figure 2 As shown, the transmission pin 321 is connected to the upper end of the connecting rod 33, and the lower end of the connecting rod 33 is rotatably connected to the drive arm 5. The connecting rod 33 serves as a transmission mechanism, converting the rotation of the crank 32 into the up-and-down movement of the drive arm 5.

[0045] like Figure 1 , Figure 2 As shown, a guide rail 12 and a slider 13 are provided on the housing 1. The guide rail 12 is vertically arranged, and the slider 13 is slidably mounted on the guide rail 12. The slider 13 can reciprocate along the length of the guide rail 12. The drive arm 5 is hinged to the slider 13, as shown. Figure 3 As shown, a cylindrical pin 53 is provided at the left end of the drive arm 5. The pin 53 is inserted into the slider 13, so that the drive arm 5 and the slider 13 move up and down synchronously. The main body of the drive arm 5 is cylindrical, and the cylinder is located between the pin 53 and the arm fork structure 52. This main body is hinged to the connecting rod 33, and the two can rotate relative to each other.

[0046] Combination Figure 1 , Figure 2 As shown, the swing drive mechanism 4 includes a transmission belt 41 and a rotating block 42. The rotating block 42 is rotatably mounted on the frame and can rotate around the shaft. A pulley is mounted on the rotating block 42 and can mesh with the transmission belt 41. The rotation of the rotating block 42 is driven by the movement of the transmission belt 41.

[0047] The rotating block 42 has an eccentrically set guide hole. The direction of the guide hole is at an angle to the axis of rotation of the rotating block 42. When the axis of rotation of the rotating block 42 is vertical, the guide hole is not vertical, and the needle bar 2 is slidably inserted into the guide hole. When the rotating block 42 rotates around the axis, it can drive the needle bar 42 to make a conical swing.

[0048] Combination Figure 2 As shown, the needle bar 2 is provided with a flat rectangular section 21, which is used for sliding engagement with the rotating block 42. The cross-section of the flat rectangular section 21 is not circular. One or two planes can be milled on the cylindrical section 21, or protrusions can be provided on the cylindrical section 21. The angle of the needle bar 2 is limited by the flat rectangular section 21 to prevent the needle bar 2 from rotating on its own.

[0049] Combination Figure 2 As shown, the upper sleeve 11 includes an outer ring 111 and an inner ring 112. The outer ring 111 is fixedly assembled to the housing 1, for example, by bolts or interference fit. The inner ring 112 is rotatably assembled within the outer ring 111, and the outer ring 111 and the inner ring 112 form a ball joint. The housing 1 is provided with a recessed platform for accommodating and supporting the outer ring 111, and the recessed platform structure facilitates the positioning of the upper sleeve 11.

[0050] The present invention also provides a round-head buttonhole machine, including the above-mentioned needle bar drive device, which can achieve the same technical effect.

[0051] A sewing needle is installed at the end of the needle bar 2, or a needle tip is set at the lower end of the needle bar 2 itself. Through the linear reciprocating translation of the needle bar 2 and the conical oscillation, stitches are formed on the fabric along a circular path.

[0052] This invention utilizes a drive arm 5, a retaining ring 6, and a washer 61 to form a cooperative structure, allowing the needle bar 2 to rotate freely and slide axially within the drive arm 5. It enables arbitrary positional adjustments in all five degrees of freedom, leaving only the vertical movement of the needle bar 2 limited by the retaining ring 6. This creates a universal oscillating needle bar drive structure. This invention differs significantly from existing solutions. It employs a single-sided pin shaft to drive a fork-shaped arm structure, which then uses the interaction of an arc and a plane to achieve arbitrary oscillation of the needle bar within a certain range. This design is simplified, lightweight, and significantly reduces high-speed inertia, enabling high-speed needle bar operation. Currently, the industry's highest speed of 2500 rpm is insufficient to meet market demands; this solution can increase the speed to 3000 rpm.

[0053] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A needle bar driving device, characterized in that, Includes housing (1), needle bar (2), up and down drive mechanism (3), and swing drive mechanism (4). A drive arm (5) is mounted on the needle bar (2), and two retaining rings (6) are fixedly mounted on the needle bar (2). The retaining rings (6) fix the drive arm (5) and the needle bar (2) relative to each other on the axis of the needle bar (2). The drive arm (5) is provided with a notch for accommodating the rotation of the needle bar (2). The drive arm (5) is provided with protrusions (51) protruding upward and downward respectively. The two retaining rings (6) respectively cooperate with the arc surface of the protrusions (51) so that the needle bar (2) can swing conically relative to the drive arm (5). The housing (1) is provided with an upper sleeve (11) for cooperating with the needle bar (2). The upper and lower drive mechanism (3) enables the drive arm (5) to drive the needle bar (2) to slide relative to the upper sleeve (11). The swing drive mechanism (4) drives the needle bar (2) to make a conical swing with the upper sleeve (11) as the rotation center.

2. The needle bar driving device according to claim 1, characterized in that, The drive arm (5) is provided with a semi-enclosed notch, and the protrusion (51) is provided at the edge of the notch of the drive arm (5).

3. The needle bar driving device according to claim 2, characterized in that, The radial length of the protrusion (51) is less than or equal to the wall thickness of the drive arm (5); the circumferential length of the protrusion (51) is equal to the radial length of the protrusion (51).

4. The needle bar driving device according to claim 1, characterized in that, A washer (61) is clamped between the retaining ring (6) and the protrusion (51); the washer (61) is provided with an arc-shaped groove for engaging with the arc-shaped surface of the protrusion (51).

5. The needle bar driving device according to claim 1, characterized in that, The side wall of the retaining ring (6) is provided with a threaded hole (62) for screwing in the tightening screw, and the end of the tightening screw can be pressed against the side wall of the needle bar (2) to achieve tightening and fixing.

6. The needle bar driving device according to claim 1, characterized in that, The up-and-down drive mechanism (3) includes a main drive shaft (31), a crank (32) and a connecting rod (33). The main drive shaft (31) is used to drive the crank (32) to rotate. A transmission pin (321) is eccentrically provided on the crank (32). The transmission pin (321) is rotatably connected to one end of the connecting rod (33), and the other end of the connecting rod (33) is rotatably connected to the drive arm (5). The housing (1) is provided with a guide rail (12) and a slider (13). The drive arm (5) is hinged to the slider (13). The slider (13) can reciprocate along the length direction of the guide rail (12).

7. The needle bar driving device according to claim 1, characterized in that, The swing drive mechanism (4) includes a transmission belt (41) and a rotating block (42). The rotating block (42) has an eccentrically arranged guide hole. The through direction of the guide hole is at an angle to the rotation axis of the rotating block (42). The needle bar (2) is slidably inserted into the guide hole.

8. The needle bar drive device according to claim 7, characterized in that, The needle bar (2) is provided with a flat square section (21), which is used for sliding engagement with the rotating block (42).

9. The needle bar driving device according to claim 1, characterized in that, The upper sleeve (11) includes an outer ring (111) and an inner ring (112). The outer ring (111) is fixedly mounted on the housing (1), and the inner ring (112) is rotatably mounted on the outer ring (111). The housing (1) is provided with a platform for accommodating and supporting the outer ring (111).

10. A round-head buttonhole machine, characterized in that, Includes the needle bar drive device as described in any one of claims 1 to 9.

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