Driving mechanism for thread trimming, thread loosening and presser foot lifting of sewing machine

Abstract

The utility model belongs to the technical field of sewing machines. The sewing machine solves the problem that in the prior art, a sewing machine is complex and tedious in structure. The driving mechanism comprises a driving motor installed on a machine shell, an output shaft of the driving motor is connected with a fixing frame, the machine shell is rotationally provided with a rotating shaft coaxial with the output shaft, and the two ends of the rotating shaft are fixedly connected with a thread loosening crank and a lifting crank respectively. The thread loosening crank is connected with the thread clamping device assembly through the thread loosening connecting rod, one side of the fixing frame is connected with a first roller which abuts against the top end of the thread trimming connecting rod in a pressing mode, when the driving motor rotates forwards, the first roller can drive the thread trimming connecting rod to move downwards, and the other side of the fixing frame is connected with a second roller which abuts against the thread loosening crank in a pressing mode, and when the driving motor rotates backwards. The second rolling wheel can push the thread loosening crank to swing so that the lifting crank can drive the presser foot lifting connecting rod to move upwards, and meanwhile the thread clamping device assembly loosens threads. The driving device has the advantages of simplifying the driving structure of the sewing machine and reducing the manufacturing cost.

Description

Technical Field

[0001] This utility model belongs to the field of sewing machine technology and relates to a drive mechanism for cutting thread, loosening thread, and lifting presser foot in a sewing machine. Background Technology

[0002] A sewing machine is mainly used for joining and splicing sewn pieces, suitable for various knitted and woven fabrics. Existing sewing machines include a thread-cutting assembly, a thread clamping assembly, and a presser foot lifting assembly. The thread-cutting assembly includes a first electromagnet installed at the tail of the machine head, a rotating shaft, a connecting rod, and a blade holder with a thread-cutting blade located in the machine head. The first electromagnet is connected to the blade holder via the rotating shaft and connecting rod, and its downward movement is achieved through the first electromagnet. The thread clamping assembly needs to be released during thread feeding; existing sewing machines use a second electromagnet installed on the machine housing to release the thread from the clamping assembly. The presser foot lifting assembly includes a third electromagnet installed at the tail of the machine head, a rotating shaft, a connecting rod, and a presser foot located in the machine head. The third electromagnet is connected to the presser foot via the rotating shaft and connecting rod, and its lifting action is achieved through the third electromagnet.

[0003] Existing stitching machines require multiple drivers to achieve thread cutting, thread loosening, and presser foot lifting, resulting in high hardware costs. Furthermore, the multiple drivers and related components occupy a significant amount of installation space, making the stitching machine's structure complex and cumbersome. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned problems in existing technologies by proposing a drive mechanism for thread cutting, thread loosening, and presser foot lifting in a sewing machine. The technical problem this invention aims to solve is how to simplify the drive structure of a sewing machine and reduce manufacturing costs.

[0005] The objective of this utility model can be achieved through the following technical solutions:

[0006] A drive mechanism for thread cutting, thread loosening, and presser foot lifting in a sewing machine. The sewing machine includes a machine housing and a thread cutting assembly, a presser foot lifting assembly, and a thread clamping assembly respectively disposed on the machine housing. The thread cutting assembly includes a thread cutting connecting rod sleeved with a compression spring and passing through the machine housing. The presser foot lifting assembly includes a presser foot lifting connecting rod sleeved with a tension spring and passing through the machine housing. The drive mechanism is characterized by including a drive motor mounted on the machine housing, a fixed frame connected to the output shaft of the drive motor, and a rotating shaft rotatably disposed on the machine housing, coaxial with the output shaft. The two ends of the rotating shaft are... The device is fixedly connected to a loosening crank and a lifting crank. The loosening crank is connected to the wire clamp assembly via a loosening connecting rod. One side of the fixing frame is connected to a first roller that presses against the top of the wire cutting connecting rod. When the drive motor rotates forward, the first roller can drive the wire cutting connecting rod to move downward. The other side of the fixing frame is connected to a second roller that presses against the loosening crank. When the drive motor rotates in reverse, the second roller can push the loosening crank to swing, so that the lifting crank drives the lifting foot connecting rod to move upward, while the wire clamp assembly loosens the wire.

[0007] The drive mechanism for thread cutting, thread loosening, and presser foot lifting in this sewing machine is achieved by mounting a first roller on the output shaft of the drive motor via a fixed bracket. This roller is used to perform the thread cutting action of the thread cutting component and a second roller is used to perform the thread loosening action of the thread clamping component. Simultaneously, the second roller drives a lifting crank via a rotating shaft to synchronously achieve the presser foot lifting action of the presser foot lifting component. These actions do not interfere with each other. Thus, the actions of thread cutting, thread loosening, and presser foot lifting are controlled by the forward and reverse rotation of a single drive motor. This achieves multi-functional distribution of a single power source, reduces redundant parts, simplifies the drive structure of the sewing machine, and significantly reduces the number of drive units, thereby reducing manufacturing costs.

[0008] In addition, using the first roller can reduce its friction with the wire-cutting connecting rod, and similarly, the second roller can reduce its friction with the wire-releasing crank, thus reducing noise and energy loss.

[0009] Specifically, when the sewing is completed and the thread needs to be cut, the drive motor drives the fixed frame to rotate forward. The first roller on the fixed frame overcomes the elastic force of the compression spring and pushes the thread-cutting connecting rod downward along the through hole in the machine housing. The cutter connected to the blade holder at the bottom of the thread-cutting connecting rod performs the thread-cutting action. Then, the drive motor drives the fixed frame to return to its original position. Under the action of the compression spring, the thread-cutting connecting rod drives the blade holder and cutter on it to return to their original positions synchronously. Then, the drive motor drives the fixed frame to rotate in reverse. The second roller on the fixed frame drives the thread-releasing crank to rotate. At the same time, the thread-releasing crank drives the thread clamp assembly to release the thread through the thread-releasing connecting rod. Simultaneously, the lifting crank drives the presser foot lifting connecting rod to move upward, realizing the presser foot lifting action. Then, the drive motor drives the fixed frame to return to its original position, the thread clamp assembly returns to its original position, and under the action of the tension spring, the presser foot lifting connecting rod and the presser foot on it return to their original positions.

[0010] In the aforementioned drive mechanism for thread cutting, thread loosening, and presser foot lifting in a sewing machine, a lifting crank is sleeved at the top of the presser foot lifting linkage. One end of the lifting crank is sleeved on the rotating shaft, and the other end is in an upward-curving arc shape, abutting against the lower end surface of the lifting crank. This allows the lifting crank to better drive the presser foot lifting linkage upward when it rotates.

[0011] In the aforementioned drive mechanism for thread cutting, thread loosening, and presser foot lifting in a sewing machine, the first roller, the second roller, and the upward-curved end of the lifting crank are all located on the same side of the rotating shaft, with the second roller and the first roller offset vertically. This allows the first roller to better drive the thread cutting linkage downwards, the second roller to better drive the thread loosening crank to rotate, the thread loosening crank to better drive the thread loosening connecting rod backwards, and the thread loosening crank to better drive the lifting crank to rotate, thus allowing the lifting crank to better drive the presser foot lifting linkage upwards during rotation.

[0012] In the aforementioned drive mechanism for cutting thread, loosening thread, and lifting presser foot in a sewing machine, the fixed frame has a socket hole with a notch along its edge, and the fixed frame is also equipped with fastening bolts that pass through both sides of the notch. This makes it easier to assemble and disassemble the fixed frame from the drive shaft of the drive motor.

[0013] In the aforementioned drive mechanism for thread cutting, thread loosening, and presser foot lifting in a sewing machine, the width of the thread loosening crank facing the sidewall of the second roller is greater than the thickness of the second roller. This allows the second roller to better drive the thread loosening crank to rotate, preventing them from disengaging.

[0014] Compared with existing technologies, the advantages of the drive mechanism for thread cutting, thread loosening, and presser foot lifting in this sewing machine are as follows: The drive mechanism for thread cutting, thread loosening, and presser foot lifting in this sewing machine has a first roller for cutting the thread of the thread cutting component and a second roller for loosening the thread of the thread clamping component, which are fixed on the output shaft of the drive motor. At the same time, the second roller drives the lifting crank through the rotating shaft to synchronously lift the presser foot of the lifting component. The two rollers do not interfere with each other. Thus, the actions of thread cutting, thread loosening, and presser foot lifting are controlled by the forward and reverse rotation of a single drive motor. This achieves multi-functional distribution of a single power source, reduces redundant parts, simplifies the drive structure of the sewing machine, and significantly reduces the number of drive units, thereby reducing manufacturing costs. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural diagram of the drive mechanism for cutting thread, loosening thread, and lifting presser foot of this sewing machine.

[0016] Figure 2 This is a three-dimensional structural diagram of the sewing machine's drive mechanism for cutting thread, loosening thread, and lifting presser foot after the machine casing has been removed.

[0017] Figure 3 This is an exploded view of the sewing machine's drive mechanism for cutting thread, loosening thread, and lifting presser foot after the machine casing has been removed.

[0018] Figure 4 This is a three-dimensional structural diagram of the drive mechanism fixing frame, first roller, and second roller of this sewing machine for cutting thread, loosening thread, and lifting presser foot.

[0019] In the diagram: 1. Housing; 2. Wire cutting assembly; 2a. Wire cutting connecting rod; 2b. Compression spring; 3. Presser foot lifting assembly; 3a. Presser foot lifting connecting rod; 3b. Tension spring; 3c. Presser foot; 4. Wire clamping assembly; 4a. Base frame; 4b. Wire loosening rod; 4c. Torsion spring; 4d. Rotating crank; 4e. Connecting rod; 5. Drive motor; 5a. Output shaft; 6. Fixing bracket; 6a. Socket hole; 6b. Notch; 6c. Fastening bolt; 7. Rotating shaft; 8. Wire loosening crank; 9. Lifting crank; 10. Wire loosening connecting rod; 11. First roller; 12. Second roller; 13. Lifting crank; 14. Blade holder; 15. Cutting blade. Detailed Implementation

[0020] The following are specific embodiments of the present invention, described in conjunction with the accompanying drawings, to further illustrate the technical solution of the present invention. However, the present invention is not limited to these embodiments. A drive mechanism for cutting thread, loosening thread, and lifting the presser foot of a sewing machine, as shown in the attached drawings. Figure 1-4 The sewing machine includes a housing 1 and a thread-cutting assembly 2, a presser foot assembly 3, and a thread clamping assembly 4, all respectively mounted on the housing 1. The thread-cutting assembly 2 includes a thread-cutting connecting rod 2a fitted with a compression spring 2b and passing through the housing 1. The presser foot assembly 3 includes a presser foot connecting rod 3a fitted with a tension spring 3b and passing through the housing 1. The drive mechanism includes a drive motor 5 mounted on the housing 1. The drive motor 5 is preferably a stepper motor. A fixing bracket 6 is connected to the output shaft 5a of the drive motor 5. A rotating shaft 7, coaxial with the output shaft 5a, is rotatably mounted on the housing 1. Thread slack is fixedly connected to both ends of the rotating shaft 7. The cable loosening crank 8 and the lifting crank 9 are connected to the cable clamp assembly 4 via the cable loosening connecting rod 10. One side of the fixing frame 6 is connected to a first roller 11 that presses against the top of the cable cutting connecting rod 2a. When the drive motor 5 rotates forward, the first roller 11 can drive the cable cutting connecting rod 2a to move downward. The other side of the fixing frame 6 is connected to a second roller 12 that presses against the cable loosening crank 8. When the drive motor 5 rotates in reverse, the second roller 12 can push the cable loosening crank 8 to swing so that the lifting crank 9 drives the lifting foot connecting rod 3a to move upward while the cable clamp assembly 4 loosens the cable.

[0021] Reference Figure 2Specifically, the top end of the lifting foot connecting rod 3a is fitted with a lifting crank 13, one end of the lifting crank 9 is fitted onto the rotating shaft 7, and the other end is in an upward-curving arc shape and abuts against the lower end surface of the lifting crank 13.

[0022] Reference Figure 2 More specifically, the first roller 11, the second roller 12, and the upward-curved end of the lifting crank 9 are all located on the same side of the rotating shaft 7, and the second roller 12 and the first roller 11 are staggered vertically.

[0023] In this embodiment, the fixing frame 6 preferably has a socket 6a, and the edge of the socket 6a has a notch 6b. The fixing frame 6 is also provided with fastening bolts 6c passing through both sides of the notch 6b. Preferably, the width of the loosening crank 8 facing the side wall of the second roller 12 is greater than the thickness of the second roller 12.

[0024] The following describes the working principle of the drive mechanism for thread cutting, thread loosening, and presser foot lifting of this sewing machine:

[0025] The wire clamp assembly 4 is an existing structure. Specifically, the wire clamp assembly 4 includes a base frame 4a mounted on the housing 1 and a wire loosening rod 4b rotatably and horizontally mounted on the base frame 4a. A torsion spring 4c is sleeved on the wire loosening rod 4b, with one end of the torsion spring 4c connected to the wire loosening rod 4b and the other end connected to the base frame 4a. A rotating crank 4d is sleeved on the wire loosening rod 4b, and the rotating crank 4d is connected to the wire loosening connecting rod 10 via a connecting rod 4e. The connection is as follows: the loosening connecting rod 10 drives the connecting rod 4e to move backward, causing the rotating crank 4d to drive the loosening rod 4b to rotate, thus loosening the wire in the wire clamp assembly 4. The torsion spring 4c can reset the rotating crank 4d, the connecting rod 4e, and the loosening connecting rod 10 through the loosening rod 4b. Specifically, under the action of the torsion spring 4c, the loosening rod 4b and the rotating crank 4d rotate in opposite directions, the wire clamp assembly 4 re-clamps the wire, and the connecting rod 4e moves forward, causing the loosening crank 4d to return to its original position.

[0026] When the sewing is finished and the thread needs to be cut, the drive motor 5 drives the fixed frame 6 to rotate forward. The first roller 11 on the fixed frame 6 overcomes the elastic force of the compression spring 2b and pushes the thread cutting connecting rod 2a downward along the through hole of the machine housing 1. The cutter connected to the blade holder at the bottom of the thread cutting connecting rod 2a performs the thread cutting action. Then, the drive motor 5 drives the fixed frame 6 to return to its original position. Under the action of the compression spring 2b, the thread cutting connecting rod 2a drives the blade holder 14 and the cutter 15 on it to return to their original positions synchronously. Then, the drive motor 5 drives the fixed frame 6 to rotate in reverse. The second roller 12 on the fixed frame 6 drives the thread loosening crank 8 to rotate. At the same time, the thread loosening crank 8 drives the thread loosening connecting rod 10 to move backward, and drives the rotating shaft 7 and the sleeve on the rotating shaft 7. The lifting crank 9 rotates synchronously (the rotating shaft 7 and the output shaft 5a of the drive motor 5 are coaxially arranged and have a gap between them, so that the output shaft 5a of the drive motor 5 will not directly drive the rotating shaft 7 to rotate). The loosening connecting rod 10 loosens the wire by rotating the crank 4d to drive the loosening rod 4b to rotate. The upward tilting end of the lifting crank 9 acts on the lifting crank 13 to drive the lifting foot connecting rod 3a to move upward, realizing the lifting foot action. Then, the drive motor 5 drives the fixing frame 6 to return to its original position. Under the action of the torsion spring 4c, the loosening connecting rod 10, the loosening rod 4b and the rotating crank 4d return to their original positions. Under the action of the tension spring 3b, the lifting foot connecting rod 3a and the pressure foot 3c on it return to their original positions.

[0027] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.

Claims

1. A driving mechanism for thread cutting, thread loosening and presser foot lifting of a sewing machine, the sewing machine comprising a machine housing (1) and a thread cutting assembly (2), a presser foot lifting assembly (3) and a thread clamping assembly (4) arranged on the machine housing (1) respectively, the thread cutting assembly (2) comprising a thread cutting connecting rod (2a) sleeved with a compression spring (2b) and penetrating through the machine housing (1), the presser foot lifting assembly (3) comprising a presser foot lifting connecting rod (3a) sleeved with a tension spring (3b) and penetrating through the machine housing (1), characterized in that, The driving mechanism comprises a driving motor (5) mounted on the casing (1), a fixed frame (6) connected to an output shaft (5a) of the driving motor (5), a rotating shaft (7) coaxial with the output shaft (5a) rotatably arranged on the casing (1), a line loosening crank (8) and a lifting crank (9) fixedly connected to two ends of the rotating shaft (7) respectively, the line loosening crank (8) being connected to the thread clamp assembly (4) through a line loosening connecting rod (10), one side of the fixed frame (6) being connected to a first roller (11) abutting against a top end of the thread cutting connecting rod (2a), and the first roller (11) being capable of driving the thread cutting connecting rod (2a) to move downward when the driving motor (5) rotates in a forward direction, the other side of the fixed frame (6) being connected to a second roller (12) abutting against the line loosening crank (8), and the second roller (12) being capable of driving the line loosening crank (8) to swing to drive the lifting crank (9) to drive the presser foot connecting rod (3a) to move upward and the thread clamp assembly (4) to loosen the thread when the driving motor (5) rotates in a reverse direction.

2. The thread trimming, loosening and presser foot lifting mechanism of a sewing machine according to claim 1, wherein A lifting crank (13) is sleeved on a top end of the presser foot connecting rod (3a), and one end of the lifting crank (9) is sleeved on the rotating shaft (7), and the other end thereof is in an upwardly curved shape and abuts against a lower end face of the lifting crank (13).

3. The thread trimming, loosening and presser foot lifting mechanism of a sewing machine according to claim 2, wherein The first roller (11), the second roller (12) and the upwardly curved end of the lifting crank (9) are located on the same side of the rotating shaft (7), and the second roller (12) and the first roller (11) are arranged in a staggered manner.

4. The thread trimming, loosening and presser foot lifting mechanism of a sewing machine according to claim 1 or 2 or 3, wherein The fixed frame (6) is provided with a sleeving hole (6a) having a notch (6b) on an edge thereof, and the fixed frame (6) is further provided with a fastening bolt (6c) penetrating through both sides of the notch (6b).

5. The thread trimming, loosening and presser foot lifting mechanism of a sewing machine according to claim 1 or 2 or 3, wherein The line loosening crank (8) is wider than the thickness of the second roller (12) in a direction facing the side wall of the second roller (12).

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