A thread taking-up mechanism for a sewing machine

Abstract

The present invention discloses a thread taking-up mechanism of a sewing machine, the technical scheme of which includes a main shaft and a casing on a sewing machine body, a thread taking-up rod and a needle bar being arranged on the main shaft, the thread taking-up rod extending out of the side wall of the casing and swinging back and forth in a curved trajectory, the needle bar extending out through the bottom of the casing and making reciprocating motion in the vertical direction, a needle being arranged at the protruding end of the needle bar; a thread clamp, a thread loosening hook and an adjusting frame are further arranged on the side of the casing where the thread taking-up rod extends out, the adjusting frame being arranged between the thread clamp and the thread taking-up rod, the thread loosening hook being connected to the main shaft through a transmission mechanism, the sewing thread being passed through the thread clamp, the adjusting frame, the thread taking-up rod and the needle in sequence, the present invention has a thread compensation function, which prevents the sewing thread from being too tight or too loose to cause unsightly stitches, and at the same time improves the needle insertion accuracy, and the thread amount is adjustable, which can assist the thread taking-up mechanism in controlling the thread amount, and can sew excellent and smooth stitches for fabrics of different thicknesses.

Description

Technical Field

[0001] The present invention relates to the technical field of sewing machines, and more particularly to a thread taking-up mechanism for sewing machines. Background Art

[0002] Currently, sewing machines are all equipped with a thread take-up mechanism. Existing thread take-up mechanisms generally have a long slot extending up and down on the sewing machine housing that allows a thread take-up lever to swing up and down. The thread take-up lever is driven by the main shaft of the sewing machine to swing back and forth within the slot. Simultaneously, the main shaft of the sewing machine also drives the needle to move up and down. The coordinated action of the needle and thread take-up lever achieves the thread take-up function. However, the above-mentioned prior art has drawbacks: the thread take-up mechanism has a fixed structure and cannot adapt well to both thin and thick materials. Specifically, when sewing thin and thick materials of different fabric thicknesses, the needle thread cannot be stably taken up; if the needle thread is taken up enough for thin materials, the needle thread will not be taken up tightly when sewing thick materials; if the needle thread is taken up enough for thick materials, the needle thread will be taken up too tightly when sewing thin materials, causing wrinkles on the thin materials. This prevents the formation of smooth and fine sewing seams, resulting in poor sewing quality. In addition, the existing thread picking mechanism is prone to pulling the needle when the needle moves up and down. That is, when the needle is in the stitching stage, the sewing thread is too tight, causing the needle to bend, resulting in errors in stitching and affecting the sewing quality. Summary of the Invention

[0003] In response to the shortcomings of the existing technology, the present invention provides a sewing machine thread take-up mechanism with a thread compensation function to prevent the sewing thread from being too tight or too loose, resulting in unsightly stitches. At the same time, the needle insertion accuracy is improved, and the thread amount is adjustable, which can assist the thread take-up mechanism in controlling the thread amount, and can sew excellent and smooth seams for fabrics of different thicknesses.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a sewing machine thread taking-up mechanism comprises a sewing machine body, the sewing machine body comprises a main shaft and a casing, the main shaft is provided with a thread take-up rod and a needle bar, the thread take-up rod extends out of the side wall of the casing, and swings back and forth in a curved trajectory, the needle bar extends through the bottom of the casing, makes reciprocating motion in the vertical direction, and is provided with a needle at the protruding end, characterized in that: the casing is also provided with a thread clamp, a thread loosening hook and an adjusting frame on the side where the thread take-up rod extends, the thread loosening hook is connected to the main shaft through a transmission mechanism, the adjusting frame is provided between the thread clamp and the thread take-up rod, a long slot hole is provided on the adjusting frame, the long slot hole is detachably connected to the casing by a screw, and the adjusting frame is also provided with two thread passing holes opposite to the thread loosening hook, the thread passing hole, the thread loosening hook and the needle are passed through the thread clamp, the thread passing hole, the thread loosening hook and the needle in sequence.

[0005] The present invention is further configured as follows: the transmission mechanism includes an eccentric cam, a wire loosening connecting rod, a wire loosening crank and a transmission shaft, the eccentric cam is connected to the main shaft, one end of the wire loosening connecting rod is connected to the eccentric cam bearing, and the other end is hinged to the wire loosening crank, one end of the transmission shaft is fixedly connected to the wire loosening hook, and the other end is connected to the wire loosening crank shaft.

[0006] The present invention is further configured as follows: a crank is provided on the main shaft, a thread take-up link and a needle link are provided on the crank, the thread take-up link and the needle link are respectively connected to the thread take-up link and the needle bar, the transmission mechanism includes a first link, a second link and a third link, the thread release hook is hinged to the first link, the third link is hinged to the thread take-up link, the first link and the third link are both hinged to the second link, and the hinge axis of the third link and the second link is eccentrically set.

[0007] The present invention is further configured as follows: the protruding end of the thread loosening hook is bent upward into a hook shape and is located below the sewing thread, so that the thread loosening hook can stably pick up the sewing thread when moving upward, and does not apply external force to the sewing thread when moving downward.

[0008] The present invention is further configured as follows: a through hole is further provided on the casing, the wire loosening connecting rod extends through the through hole, and the wire loosening crank and the transmission shaft are both arranged outside the casing.

[0009] The present invention is further configured as follows: the end of the thread loosening hook is in the shape of a hook bent downward, used for hooking the sewing thread, and is located above the sewing thread, so that the thread loosening hook can hook the sewing thread when moving downward, and does not apply external force to the sewing thread when moving upward.

[0010] The present invention is further configured such that: the line loosening hook swings back and forth up and down as the main shaft rotates.

[0011] In summary, the present invention has the following beneficial effects:

[0012] Compared with the prior art, the present invention is provided with a thread loosening hook and a transmission mechanism. When the main shaft rotates, the thread loosening hook cooperates with the needle bar and the thread take-up rod to move, hooks the sewing thread and pulls it, and releases the sewing thread when the needle is lowering the needle, so that the subsequent sewing thread on the thread take-up rod and the needle is in a relaxed state, so that the sewing thread will not over-tighten the needle, and solves the problem of the prior art that during the needle lowering stage, the sewing thread is too tight, causing the needle to bend, resulting in errors in needle lowering and affecting the sewing quality.

[0013] At the same time, the present invention also provides an adjusting frame, which is provided with a long slot hole, and a screw is provided in the hole to connect with the casing. The operator can change the position of the adjusting frame by adjusting the position of the screw in the long slot hole. After the position of the adjusting frame is changed, the position of the sewing thread passing through the thread hole on it will be changed, and the swing stroke of the thread loosening hook is fixed. After the position of the sewing thread is changed, the distance that the thread loosening hook can pull the sewing thread is changed, that is, the thread adjustment amount is changed. Therefore, the operator can change the position of the adjusting frame as needed to achieve the purpose of controlling the thread amount, and by controlling different thread amounts, the thread take-up rod is assisted in taking up the thread of fabrics of different thicknesses, solving the problem that the structure of the thread take-up mechanism in the prior art is fixed and cannot be adjusted, making it impossible to form smooth and excellent sewing lines on fabrics of different thicknesses. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the external structure of the thread take-up lever side of the first embodiment;

[0015] Figure 2 This is a schematic diagram of the external structure of the through-hole side of the first embodiment;

[0016] Figure 3 This is a schematic diagram of the internal structure of the first embodiment;

[0017] Figure 4 This is a schematic diagram of the transmission mechanism structure when the line release hook is in a low position in the first embodiment of the present invention;

[0018] Figure 5 This is a schematic diagram of the transmission mechanism structure when the line release hook is in a high position in the first embodiment of the present invention;

[0019] Figure 6 This is a schematic diagram of the external structure of the sewing machine body of the second embodiment;

[0020] Figure 7 This is a schematic diagram of the side wall structure of the casing of the second embodiment;

[0021] Figure 8 This is a schematic diagram of the internal structure of the second embodiment;

[0022] Figure 9 This is a schematic diagram of the second needle bar low point structure of this embodiment;

[0023] Figure 10 This is a schematic diagram of the needle bar high point structure of the second embodiment.

[0024] Figure numerals: 1. sewing machine body; 101. main shaft; 102. machine casing; 2. thread take-up lever; 3. needle bar; 4. needle; 5. thread clamp; 6. thread release hook; 7. adjustment frame; 701. long slot hole; 702. thread passing hole; 8. crank; 9. thread take-up connecting rod; 10. needle connecting rod; 11. first connecting rod; 12. second connecting rod; 13. third connecting rod; 14. eccentric cam; 15. thread release connecting rod; 16. thread release crank; 17. transmission shaft; 18. through hole. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below with reference to the accompanying drawings.

[0026] Example 1:

[0027] like Figure 1-5 As shown, the sewing machine comprises a main body 1, which comprises a main shaft 101 and a casing 102. A thread take-up lever 2 and a needle bar 3 are provided on the main shaft 101. The thread take-up lever 2 extends out of the side wall of the casing 102, and its extended end swings back and forth in a curved trajectory. The needle bar 3 extends through the bottom of the casing 102 and makes a reciprocating motion in the vertical direction. A needle 4 is provided at the extended end of the needle bar 3. A thread clamp 5, a thread release hook 6 and an adjustment frame 7 are further provided on the side of the casing 102 where the thread take-up lever 2 extends. The adjustment frame 7 is provided between the thread clamp 5 and the thread take-up lever 2. The thread-releasing hook 6 is located between the two threads and below the thread-taking rod 2. The thread-releasing hook 6 is connected to the main shaft 101 through a transmission mechanism. The sewing thread passes through the thread clamp 5, the adjustment frame 7, the thread-taking rod 2 and the needle 4 in sequence. Therefore, when sewing, when the needle 4 moves upward, the thread-releasing hook 6 drops, hooks the sewing thread passing through the two thread holes 702 and pulls it down. When the needle 4 moves downward, the thread-releasing hook 6 releases the sewing thread that has been pulled previously, allowing the sewing thread at the needle 4 to be in a relaxed state, and no pulling force is generated on the needle 4, thereby ensuring the accuracy of the needle position.

[0028] For further information, please refer to Figure 4 and Figure 5 The transmission mechanism includes an eccentric cam 14, a loosening connecting rod 15, a loosening crank 16 and a transmission shaft 17. The eccentric cam 14 is connected to the main shaft 101 axis, one end of the loosening connecting rod 15 is connected to the eccentric cam 14 bearing, and the other end is hinged to the loosening crank 16. One end of the transmission shaft 17 is connected to the loosening hook 6 axis, and the other end is connected to the loosening crank 16 axis. Therefore, during the rotation of the main shaft 101, the eccentric cam 14 rotates, driving the loosening connecting rod 15 connected to it by an eccentric bearing to perform linear motion in the direction perpendicular to the main shaft 101. The linear motion of the loosening connecting rod 15 drives the loosening crank 16 to swing, and the loosening crank 16 is connected to the transmission shaft 17 axis, converting the swing back into a small reciprocating rotation on the transmission shaft 17. Finally, the transmission shaft 17 transmits the torque to the loosening hook 6, so that the loosening hook 6 swings up and down at the far end to achieve reciprocating motion.

[0029] For further information, please refer to Figure 1 , a long slot hole 701 is provided on the adjusting frame 7, and the long slot hole 701 is detachably connected to the casing 102 by a screw. Two thread holes 702 are also provided opposite the adjusting frame 7, and the thread loosening hook 6 is located between the two thread holes 702. The design of the long slot hole 701 allows the adjusting frame 7 to have a certain adjustment space. You only need to loosen the screw and change the position of the long slot hole 7 and the screw to change the thread amount. It can be adjusted according to the thickness of the fabric to ensure that the sewing seam is smooth and beautiful.

[0030] Example 2:

[0031] Reference Figure 6 and Figure 7 , a thread clamp 5, an adjusting frame 7, a thread release hook 6, a thread take-up rod 2 and a needle 4 are provided on one side of the casing 102 at the head position of the sewing machine body 1. The sewing thread passes through the thread clamp 5 upward and then passes through the thread passing hole 702 on the adjusting frame 7, and the thread release hook 6 between the thread passing holes 702, and then continues downward to bypass the thread passing hook, pass through the thread take-up rod 2, and finally reaches the needle 4; a long slot hole 702 is provided on the adjusting frame 7, and a screw is passed through the long slot hole 702 to connect with the casing 102. When in use, the height position of the adjusting frame 7 can be changed according to the required thread amount. Because the sewing thread passes through the thread passing hole 702 on the adjusting frame 7, the adjusting frame 7 The height change causes the height of the sewing thread to change, and the upward lifting distance of the thread loosening hook 6 is fixed, and the end of the thread loosening hook 6 is a hook-shaped design, which will lift the sewing thread upward when it is upward, and will not affect the sewing thread when it is downward. If the height of the sewing thread becomes higher, the thread picking amount of the thread loosening hook 6 becomes smaller, thereby realizing the control and adjustment of the thread amount; the present invention realizes the adjustable thread amount through the thread loosening hook 6, solves the problem in the prior art that the sewing thread is too tight, causing the needle 4 to bend, and affecting the sewing accuracy. At the same time, the sewing machine can also adapt to fabrics of different thicknesses by adjusting the thread amount.

[0032] Further, the structure of the specific transmission mechanism inside the sewing machine body 1 is referred to Figures 8 to 10 When the main shaft 101 rotates, it drives the crank 8 at the end to rotate. The crank 8 is hinged with a thread take-up link 9 and a needle link 10, and the needle link 10 is hinged to the needle bar 3; the rotation of the crank 8 drives the thread take-up link 9 to move, and drives the thread take-up rod 2 and the third link 13 thereon to move. After driving the third link 13, the third link 13 drives the eccentrically hinged second link 12, and converts the rotation of the third link 13 into an up and down swing in an arc trajectory and transmits it to the first link 11. The first link 11 then controls the thread loosening hook 6 hinged to it to perform the thread taking action, thereby realizing the adjustment of the amount of sewing thread.

[0033] Further, refer to Figure 9 and Figure 10 ,exist Figure 9 When the needle 4 is in the low position, the thread release hook 6 is also in the low position and does not take up the thread. Figure 10 When the needle is in the high position, the thread-releasing hook 6 is also in the high position to pick up the sewing thread; through the action of the thread-releasing hook 6, the needle bar 3 and the needle 4, the sewing thread will not pull the needle during the needle placement process from the high position to the low position, ensuring accurate needle placement.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the design concept of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sewing machine thread take-up mechanism, comprising a sewing machine body (1), the sewing machine body (1) comprising a main shaft (101) and a housing (102), the main shaft (101) being provided with a thread take-up lever (2) and a needle bar (3), the thread take-up lever (2) extending out of a side wall of the housing (102) and swinging back and forth in a curved trajectory, the needle bar (3) extending through the bottom of the housing (102) and making a reciprocating motion in a vertical direction, and having a needle (4) provided at the extending end, characterized in that: The housing (102) is further provided with a thread clamp (5), a thread release hook (6) and an adjusting frame (7) on a side where the thread take-up rod (2) extends out. The thread release hook (6) is provided with a transmission mechanism and is connected to the main shaft (101). The adjusting frame (7) is provided between the thread clamp (5) and the thread take-up rod (2). The adjusting frame (7) is provided with a long slotted hole (701). The long slotted hole (701) is detachably connected to the housing (102) via a screw. The adjusting frame (7) is also provided with two thread passing holes (702) facing each other. The thread release hook (6) is located between the two thread passing holes (702). The sewing thread passes through the thread clamp (5), the thread passing hole (702), the thread release hook (6) and the needle (4) in sequence. The transmission mechanism comprises an eccentric cam (14), a line-loosening connecting rod (15), a line-loosening crank (16) and a transmission shaft (17); the eccentric cam (14) is connected to the main shaft (101) axis; one end of the line-loosening connecting rod (15) is connected to the eccentric cam (14) bearing, and the other end is hinged to the line-loosening crank (16); one end of the transmission shaft (17) is fixedly connected to the line-loosening hook (6), and the other end is connected to the line-loosening crank (16) axis; The main shaft (101) is provided with a crank (8), and the crank (8) is provided with a thread take-up link (9) and a needle link (10), and the thread take-up link (9) and the needle link (10) are respectively connected to the thread take-up rod (2) and the needle rod (3), and the transmission mechanism includes a first link (11), a second link (12) and a third link (13), the thread release hook (6) is hinged to the first link (11), and the third link (13) is hinged to the thread take-up link (9), the first link (11) and the third link (13) are both hinged to the second link (12), and the hinge axis of the third link (13) and the second link (12) is eccentrically arranged.

2. The thread take-up mechanism for a sewing machine according to claim 1, characterized in that: The protruding end of the thread loosening hook (6) is bent upward into a hook shape and is located below the sewing thread, so that the thread loosening hook (6) can stably pick up the sewing thread when moving upward and does not apply external force to the sewing thread when moving downward.

3. The thread take-up mechanism for a sewing machine according to claim 1, characterized in that: The housing (102) is further provided with a through hole (18), the wire-releasing connecting rod (15) extends through the through hole (18), and the wire-releasing crank (16) and the transmission shaft (17) are both arranged outside the housing (102).

4. The thread take-up mechanism for a sewing machine according to claim 1, characterized in that: The end of the thread-releasing hook (6) is in the shape of a hook bent downward, used for hooking the sewing thread, and is located above the sewing thread, so that the thread-releasing hook (6) can hook the sewing thread when it moves downward, and does not apply external force to the sewing thread when it moves upward.

5. The thread take-up mechanism for a sewing machine according to claim 1, characterized in that: The line-releasing hook (6) swings back and forth up and down as the main shaft (101) rotates.

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