Take-up mechanism of sewing machine

Abstract

The invention relates to a thread take-up mechanism of a sewing machine, a driving guide groove is formed in the middle of a thread take-up lever, the driving guide groove is a long-strip-shaped driving guide groove in the length direction of the thread take-up lever, a roller at the output end of a driving cam is contained in the driving guide groove, and the roller can roll in the driving guide groove in the length direction of the driving guide groove; one end part of the take-up lever is pivoted on the machine head shell through a pivoting part, the free end of the take-up lever penetrates out of a guide groove in the machine head shell, a thread guide hole is formed in the part, on the outer side of the machine head shell, of the free end, and the driving cam is connected with a needle bar driving device through a transmission mechanism; under the condition that the speed of the driving mechanism and the speed of the needle rod are not changed, the take-up and pay-off speed of the take-up mechanism can change along with the height change of the needle rod, especially the speed is gradually increased during final take-up, and equivalently, a tensioning action is generated on an upper thread, so that the stitched stitch is tight and more attractive.

Description

Technical Field

[0001] The invention relates to sewing machine technology, in particular to a thread taking-up mechanism of a sewing machine. Background Art

[0002] The thread taking-up mechanism of the existing sewing machine mainly includes a thread taking-up rod, the middle part of which is pivotally connected to the housing of the machine head, one end of the thread taking-up rod is connected to the driving mechanism, and the other end is provided with a wire hole; the thread feeding and releasing speeds of the existing thread taking-up mechanism change with the speed of the driving mechanism, and are synchronized with the speed of the needle bar. When the speeds of the driving mechanism and the needle bar are constant, the thread taking-up and releasing speeds of the thread taking-up mechanism are also constant. When this thread taking-up mechanism is used to sew a very thick workpiece, the resistance of the yarn after penetrating the workpiece is relatively large when it is recovered. The constant thread taking-up and releasing speeds of the existing conventional structure thread taking-up mechanism may cause the stitches to be relatively loose, not beautiful, and affect the quality of sewing. Summary of the invention

[0003] The purpose of the present invention is to provide a thread taking-up mechanism of a sewing machine. When the driving mechanism and the needle bar speed are constant, the thread taking-up and releasing speed of the thread taking-up mechanism will change with the change of the needle bar height, especially the speed gradually increases during the final thread taking-up, which is equivalent to a tensioning action on the opposite thread, thereby ensuring that the stitches of the sewing are tight and more beautiful.

[0004] To achieve the above purpose, the following technical solutions are adopted: A thread taking-up mechanism of a sewing machine comprises a machine head, wherein a thread taking-up mechanism is arranged inside the machine head, and the characteristics are as follows: the thread taking-up mechanism comprises a thread taking-up rod and a driving cam, a driving guide groove is provided in the middle of the thread taking-up rod, the driving guide groove is a long strip driving guide groove along the length direction of the thread taking-up rod, a roller at the output end of the driving cam is accommodated in the driving guide groove, the outer diameter of the roller matches the width of the driving guide groove, and the roller can roll in the driving guide groove along the length direction of the driving guide groove; one end of the thread taking-up rod is pivotally connected to the machine head housing through a pivoting portion, the free end of the thread taking-up rod passes through the guide groove on the machine head housing, a wire hole is provided on the outer part of the machine head housing at the free end, and the driving cam is connected to the needle bar driving device through a transmission mechanism.

[0005] The needle bar driving device is fixed on the outside of the machine head housing, and an active synchronous wheel and a needle bar driving cam are arranged on the output shaft of the needle bar driving device; the transmission mechanism includes a rotating shaft of the driving cam and a driven synchronous wheel on the rotating shaft, the rotating shaft is pivotally connected to the machine head housing and arranged parallel to the output shaft, and a driven synchronous wheel is also arranged on the rotating shaft of the driving cam, and the active synchronous wheel and the driven synchronous wheel are connected by a synchronous belt.

[0006] One end of the driving guide groove is close to the pivotal part of the thread take-up lever, and the other end of the driving guide groove is close to the middle part of the thread take-up lever.

[0007] The thread take-up lever is an arc-shaped structure or an L-shaped structure.

[0008] Since the present invention transfers the pivotal connection portion of the thread take-up lever from the original middle portion to the end portion of the thread take-up lever, and the driving end moves from the end portion of the thread take-up lever to between the two ends, and the position of the driving end changes at any time with the height of the needle bar, the linear speed of the wire hole at the free end of the thread take-up lever also changes with the position change of the driving end in the driving guide groove, thereby achieving a fast-later slow-later speed of releasing the thread, and a slow-later fast-later speed of winding up the thread, and finally producing a tightening effect when winding up the thread, so that the stitches are tight and more beautiful. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a structural schematic diagram of the machine head of the present invention; Figure 2 It is a schematic diagram of the internal structure of the machine head using the present invention; Figure 3 It is a structural schematic diagram of the present invention; Figure 4 It is a lateral structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0010] like Figure 1-4 As shown, a thread taking-up mechanism of a sewing machine comprises a machine head, wherein a thread taking-up mechanism is arranged inside the machine head, wherein the thread taking-up mechanism comprises a thread taking-up lever 2 and a driving cam 3, wherein a driving guide groove 21 is provided in the middle of the thread taking-up lever 2, wherein the driving guide groove 21 is a long strip-shaped driving guide groove along the length direction of the thread taking-up lever, and a roller 31 at the output end of the driving cam 3 is accommodated in the driving guide groove 21, wherein the outer diameter of the roller 31 matches the width of the driving guide groove 21, and the roller 31 can roll in the driving guide groove 21 along the length direction of the driving guide groove 21; One end of the rod 2 is pivotally connected to the machine head housing 1 through a pivot portion 22, the free end of the thread take-up rod 2 passes through the guide groove 11 on the machine head housing 1, and the free end is provided with a plurality of wire holes 23 on the outer side of the machine head housing, and the distances from each wire hole 23 to the pivot portion 22 are different; the thread take-up rod 2 is an arc structure or an L shape; one end of the driving guide groove 21 is close to the pivot portion 22 of the thread take-up rod, and the other end of the driving guide groove 21 is close to the middle of the thread take-up rod 2; the driving cam 3 is connected to the needle bar driving device 4 through a transmission mechanism.

[0011] The needle bar driving device 4 is fixed to the outside of the machine head housing 1, and an active synchronous wheel 42 and a needle bar driving cam 43 are arranged on the output shaft 41 of the needle bar driving device 4; the transmission mechanism includes a rotating shaft 32 of the driving cam 3 and a driven synchronous wheel 33 on the rotating shaft, the rotating shaft 32 is pivoted on the machine head housing 1 and arranged parallel to the output shaft 41, and the active synchronous wheel 42 and the driven synchronous wheel 33 are connected by a synchronous belt 34; the end of the rotating shaft 32 passes through the machine head housing 1, and a handle 35 is arranged at the end of the rotating shaft 32.

[0012] Since the present invention transfers the pivotal portion 22 of the thread take-up lever 2 from the original middle to the end of the thread take-up lever, and the driving end moves from the end to the middle of the thread take-up lever 2, the two ends of the thread take-up lever 2 are the pivotal portion 22 and the guide hole 23 respectively, and the position of the driving end on the thread take-up lever 2 changes with the change of the height of the wire hole 23 and the needle bar 5. In this way, on the one hand, the up and down swing amplitude of the thread take-up lever 2 can be increased to increase the length of the thread release and take-up, and on the other hand, the thread release and take-up speeds are also changed. For example, when the free end of the thread take-up lever 2 just starts to move downward, the roller 31 is in the position where the driving guide groove 21 is closest to the pivotal portion 22. At this time, the magnification of the thread take-up lever 2 is the largest, and the free end is relatively The needle bar 5 has the fastest speed. As the free end of the thread take-up rod 2 moves downward, the position of the roller 31 in the driving guide groove 21 gradually moves toward the middle of the thread take-up rod 2, and the movement speed of the thread take-up rod 2 relative to the needle bar 5 gradually slows down, and the thread releasing speed of the thread take-up rod 2 also slows down synchronously; when the free end of the thread take-up rod 2 moves to the lowest end and begins to reset upward, the speed of the thread take-up rod 2 resetting upward is just the opposite, that is, slow at first and then fast, so the thread taking-up speed is also a process of slow at first and then fast. This setting is for when the needle needs to release the thread quickly when sewing thick workpieces, which can prevent the surface thread from not keeping up with the speed of the needle, and when taking up the thread, it is first slow and then fast, and the final fast thread taking-up mainly tightens the surface thread.

[0013] The present invention arranges the thread take-up rod 2 into an arc structure or an L shape; the thread release and take-up speeds are nonlinear, and the final take-up speed is increased faster, with a better tightening effect; in this way, the stitches after sewing will not be loose but will be relatively tighter, and the stitches will be more beautiful.

[0014] In addition, the present invention has a plurality of wire holes 23 at the free end of the wire take-up rod 2 on the outer side of the head shell, and the distances from each wire hole 23 to the pivot portion 22 are different. Different wire holes 23 have different input linear speeds, and different positions of the wire holes 23 are used to adapt to workpieces of different thicknesses.

Claims

1. A thread take-up mechanism of a sewing machine, comprising a machine head, wherein the thread take-up mechanism is arranged inside the machine head, and characterized in that: The thread taking-up mechanism comprises a thread taking-up lever (2) and a driving cam (3). A driving guide groove (21) is provided in the middle of the thread taking-up lever (2). The driving guide groove (21) is a long strip-shaped driving guide groove along the length direction of the thread taking-up lever. A roller (31) at the output end of the driving cam (3) is accommodated in the driving guide groove (21). The roller (31) can roll in the driving guide groove (21) along the length direction of the driving guide groove (21). One end of the thread taking-up lever (2) is pivotally connected to the machine head housing (1) through a pivoting portion (22). The free end of the thread taking-up lever (2) passes through the guide groove (11) on the machine head housing (1). A wire hole (23) is provided on the outer part of the machine head housing. The driving cam (3) is connected to the needle bar driving device (4) through a transmission mechanism.

2. A thread take-up mechanism for a sewing machine as claimed in claim 1, characterized in that: The needle bar driving device (4) is fixed to the outside of the machine head housing (1), and an active synchronous wheel (42) and a needle bar driving cam (43) are arranged on the output shaft (41) of the needle bar driving device (4); the transmission mechanism comprises a rotating shaft (32) of the driving cam (3) and a driven synchronous wheel (33) on the rotating shaft, the rotating shaft (32) is pivotally connected to the machine head housing (1) and is arranged parallel to the output shaft (41), and the active synchronous wheel (42) and the driven synchronous wheel (33) are connected via a synchronous belt (34).

3. A thread taking-up mechanism for a sewing machine as claimed in claim 1 or 2, characterized in that: One end of the driving guide groove (21) is close to the pivotal portion (22) of the thread take-up lever, and the other end of the driving guide groove (21) is close to the middle of the thread take-up lever (2).

4. A thread taking-up mechanism for a sewing machine as claimed in claim 1, characterized in that: The thread take-up lever (2) is an arc-shaped structure or an L-shaped structure.

5. A thread taking-up mechanism for a sewing machine as claimed in claim 1, characterized in that: The outer diameter of the roller (31) matches the width of the driving guide groove (21).

6. A thread take-up mechanism for a sewing machine as claimed in claim 2, characterized in that: The end of the rotating shaft (32) passes through the machine head housing (1), and a handle (35) is provided at the end of the rotating shaft (32).

7. A thread take-up mechanism for a sewing machine as claimed in claim 1, characterized in that: A plurality of wire holes (23) are arranged on the free end of the wire take-up rod (2), and the distances between each wire hole (23) and the pivoting portion are different.

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