Upper differential adjusting mechanism of lockstitch sewing machine

Abstract

The utility model provides an upper differential adjusting mechanism of a lockstitch sewing machine, and belongs to the technical field of lockstitch sewing machines. The upper differential adjusting mechanism solves the problems that an existing upper differential adjusting mechanism is large in noise and not smooth enough. The upper differential adjusting mechanism of the lockstitch sewing machine comprises a crank and a tooth difference, one end of the crank is used for being connected with a driver, the other end of the crank is provided with a needle roller assembly, one end of the tooth difference is used for being connected with an upper feeding tooth, the other end of the tooth difference is provided with a sliding groove, the needle roller assembly comprises a needle roller bearing which is axially positioned and can rotate in the circumferential direction, and the needle roller bearing is embedded in the sliding groove. And the needle bearing can move along the groove wall of the sliding groove. The upper differential adjusting mechanism of the lockstitch sewing machine has the advantage of smooth transmission.

Description

Technical Field

[0001] The utility model belongs to the technical field of flat sewing machines, and relates to an upper differential adjusting mechanism of a flat sewing machine. Background Technique

[0002] The working principle of a flat sewing machine is that an electric motor drives the sewing needle to move up and down, and at the same time, it cooperates with the feed dog and the presser foot to convey the fabric. The bobbin and the bobbin case cooperate with each other to form a coil, and continuous stitches are formed by the interweaving of the sewing needle and the coil, so as to realize the sewing of the fabric.

[0003] When the flat sewing machine is working, it is necessary to adjust the speed and stroke of the upper feed dog to match different types of fabrics and sewing requirements. For example, a Chinese patent document discloses an upper differential feed adjusting structure for a sewing machine [Patent No.: 202021140864.0; Application Publication No.: CN212669985U], which includes a differential feed fork-shaped crank and an adjusting frame. The differential feed fork-shaped crank and the adjusting frame are respectively connected to the differential feed shaft and the upper differential feed dog structure. The adjusting frame includes a differential feed front crank, a sliding seat and a slider. The slider is arranged on the sliding seat and connected to the differential feed fork-shaped crank, and the sliding seat is adjustably sleeved on the differential feed front crank.

[0004] For the upper differential feed adjusting structure of this kind of structure, one end of the differential feed fork-shaped crank has a sliding groove, one end of the adjusting frame is fixedly connected with a cylindrical connecting rod, a slider is sleeved outside the connecting rod, the slider is square, and the slider is embedded in the sliding groove. When the slider moves along the sliding groove, the slider can rotate around the connecting rod. However, for the upper differential feed adjusting structure of this kind of structure, the contact area between the outer peripheral wall of the slider and the groove wall of the sliding groove is large, the friction force is large, and at the same time, the rotation of the slider around the connecting rod is not very smooth, and the noise is large, resulting in the transmission of the upper differential feed adjusting structure of this kind of structure not being smooth enough. Summary of the Invention

[0005] The purpose of the present utility model is to solve the above problems existing in the prior art, and provide an upper differential adjusting mechanism for a flat sewing machine, and the technical problem to be solved is how to make the transmission of the upper differential adjusting mechanism smooth.

[0006] The purpose of the present utility model can be realized by the following technical solutions: An upper differential adjusting mechanism for a flat sewing machine, including a crank and a tooth difference, characterized in that one end of the crank is used to be connected to a driver, the other end is provided with a needle roller assembly, one end of the tooth difference is used to be connected to an upper feed dog, the other end has a sliding groove, the needle roller assembly includes a needle roller bearing that can be axially positioned and circumferentially rotated, the needle roller bearing is embedded in the sliding groove, and the needle roller bearing can move along the groove wall of the sliding groove.

[0007] During operation, the driver drives the crank to swing reciprocally, causing the needle roller bearing to move back and forth along the groove wall of the sliding groove, thereby driving the differential to swing reciprocally, and ultimately achieving the forward and backward movement of the upper feed dog. This needle roller bearing is rotatable circumferentially and has a line contact with the groove wall of the sliding groove, with a small contact area, small friction, and low noise, enabling the reciprocating swing of the crank to be smoothly transmitted to the differential through the needle roller assembly, making the transmission of the upper differential adjustment mechanism smooth. The driver is a driving motor, and the forward and backward movement distance of the upper feed dog can be adjusted by adjusting the amplitude of the reciprocating rotation of the output shaft of the driver.

[0008] In the above-mentioned upper differential adjustment mechanism of a flat sewing machine, the needle roller assembly further includes a connecting rod and a locking member. The connecting rod is coaxially arranged with the needle roller bearing. One end of the connecting rod is connected to the needle roller bearing, and the other end passes through the crank and is locked with the locking member, so that the needle roller assembly is connected to the crank. This structure positions the needle roller bearing on one side of the other end of the crank, with a simple structure and convenient assembly.

[0009] In the above-mentioned upper differential adjustment mechanism of a flat sewing machine, the crank has a through hole, and the connecting rod passes through the through hole. The connecting rod has a clearance fit with the hole wall of the through hole. This structure does not lock the connecting rod and the crank, enabling the connecting rod to rotate relative to the crank, preventing jamming, and making the transmission of the upper differential adjustment mechanism smooth.

[0010] In the above-mentioned upper differential adjustment mechanism of a flat sewing machine, the locking member is a nut or a snap ring.

[0011] In the above-mentioned upper differential adjustment mechanism of a flat sewing machine, the sliding groove is U-shaped, the cross-section of the bottom of the sliding groove is semi-circular, and the groove walls on both sides of the sliding groove are parallel. This structure enables the depth of the sliding groove to be relatively short, and the space occupied by the differential is relatively small.

[0012] In the above-mentioned upper differential adjustment mechanism of a flat sewing machine, the opening of the sliding groove is arranged upward. This structure makes the lubricating oil in the sliding groove not easily fall off, improves the lubrication effect, and makes the transmission of the upper differential adjustment mechanism smooth.

[0013] In the above-mentioned upper differential adjustment mechanism of a flat sewing machine, there is a notch at the connection between the bottom and the wall of the sliding groove. When the needle roller assembly drives the differential to rotate, the connection between the bottom and the wall of the sliding groove bears the maximum force. The setting of the notch can avoid stress concentration, making the differential not easily damaged. At the same time, a certain amount of lubricating oil can be stored at the notch, improving the lubrication effect of the upper differential adjustment mechanism, thereby making the transmission of the upper differential adjustment mechanism smooth.

[0014] As another case, in the upper differential adjustment mechanism of a flat sewing machine as described above, the sliding groove is annular, the cross-sections of the bottoms of both ends of the sliding groove are semi-circular, and the groove walls on both sides of the sliding groove are parallel. This structure prevents the tooth difference from deforming during heat treatment.

[0015] Compared with the prior art, the upper differential adjustment mechanism of a flat sewing machine provided by the present utility model has the following advantages:

[0016] 1. The upper differential adjustment mechanism drives the tooth difference to swing through a needle roller bearing. The needle roller bearing is in line contact with the groove wall of the sliding groove, with a small contact area, small friction, low noise, and the needle roller bearing can rotate circumferentially and there is no jamming problem, making the transmission of the upper differential adjustment mechanism smooth.

[0017] 2. The notch of the upper differential adjustment mechanism is arranged upward, so that the lubricating oil in the sliding groove is not easily dropped, improving the lubrication effect and making the transmission of the upper differential adjustment mechanism smooth. Description of the Drawings

[0018] Figure 1 is the overall structural schematic diagram of the upper differential adjustment mechanism.

[0019] Figure 2 is the structural schematic diagram of the crank and needle roller assembly of the upper differential adjustment mechanism.

[0020] Figure 3 is the structural schematic diagram of the tooth difference of the upper differential adjustment mechanism.

[0021] In the figure, 1. Crank; 2. Tooth difference; 3. Driver; 4. Needle roller assembly; 41. Needle roller bearing; 42. Connecting rod; 43. Locking piece; 5. Upper feed dog; 6. Sliding groove; 7. Through hole; 8. Notch. Detailed Embodiments

[0022] The following are specific embodiments of the present utility model in combination with the drawings to further describe the technical solutions of the present utility model, but the present utility model is not limited to these embodiments.

[0023] As Figure 1 shown, the flat sewing machine includes a driver 3, an upper feed dog 5 and an upper differential adjustment mechanism. The upper differential adjustment mechanism includes a crank 1, a tooth difference 2 and a needle roller assembly 4.

[0024] As Figure 2As shown, one end of the crank 1 is connected to the driver 3, and the other end is provided with a needle roller assembly 4. Specifically, the needle roller assembly 4 includes a needle roller bearing 41, a connecting rod 42, and a locking member 43. The other end of the crank 1 has a through hole 7. One end of the connecting rod 42 is connected to the needle roller bearing 41, and the other end passes through the through hole 7 and is locked with the locking member 43. The connecting rod 42 is in clearance fit with the hole wall of the through hole 7. The connecting rod 42 is coaxially arranged with the needle roller bearing 41, and the needle roller bearing 41 is axially positioned and circumferentially rotatable. In this embodiment, the locking member 43 is a nut. In actual production, the locking member 43 can be a snap ring.

[0025] As Figure 3 shown, one end of the differential 2 is connected to the upper feed dog 5, and the other end has a sliding groove 6. In this embodiment, the sliding groove 6 is U-shaped, the cross-section of the bottom of the sliding groove 6 is semi-circular, the groove walls on both sides of the sliding groove 6 are parallel, the notch of the sliding groove 6 faces upward, and there is a notch 8 at the connection between the bottom and the groove wall of the sliding groove 6. In actual production, the sliding groove 6 is annular, and the cross-sections of the bottoms of both ends of the sliding groove 6 are semi-circular, and the groove walls on both sides of the sliding groove 6 are parallel.

[0026] The needle roller bearing 41 is embedded in the sliding groove 6. During operation, the driver 3 drives the crank 1 to swing reciprocally, causing the needle roller bearing 41 to move back and forth along the groove wall of the sliding groove 6, thereby driving the differential 2 to swing reciprocally, and finally realizing the forward and backward movement of the upper feed dog 5.

[0027] The specific embodiments described herein are merely illustrative of the spirit of the present utility model. Those skilled in the technical field to which the present utility model pertains can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, but will not deviate from the spirit of the present utility model or exceed the scope defined by the appended claims.

[0028] Although terms such as crank 1, differential 2, driver 3, needle roller assembly 4, needle roller bearing 41, connecting rod 42, locking member 43, upper feed dog 5, sliding groove 6, through hole 7, notch 8, etc. are used more frequently herein, the possibility of using other terms is not excluded. Using these terms is only to more conveniently describe and explain the essence of the present utility model; interpreting them as any additional limitation is contrary to the spirit of the present utility model.

Claims

1. An upper differential adjustment mechanism for a lockstitch sewing machine, comprising a crank (1) and a tooth difference (2), characterized in that: One end of the crank (1) is used to be connected to the driver (3), and the other end is provided with a needle roller assembly (4); one end of the tooth difference (2) is used to be connected to the upper feed tooth (5), and the other end has a sliding groove (6); the needle roller assembly (4) includes an axially positioned circumferentially rotatable needle roller bearing (41); the needle roller bearing (41) is embedded in the sliding groove (6), and the needle roller bearing (41) can move along the groove wall of the sliding groove (6).

2. The upper differential adjustment mechanism of a lockstitch sewing machine according to claim 1, characterized in that: The needle roller assembly (4) further comprises a connecting rod (42) and a locking piece (43); the connecting rod (42) is coaxially arranged with the needle roller bearing (41); one end of the connecting rod (42) is connected to the needle roller bearing (41), and the other end passes through the crank (1) and is locked with the locking piece (43), so that the needle roller assembly (4) is connected to the crank (1).

3. The upper differential adjustment mechanism of a lockstitch sewing machine according to claim 2, characterized in that: The crank (1) is provided with a through hole (7), the connecting rod (42) passes through the through hole (7), and the connecting rod (42) is clearance-matched with the hole wall of the through hole (7).

4. The upper differential adjustment mechanism of a lockstitch sewing machine according to claim 2, characterized in that: The locking member (43) is a nut or an open snap ring.

5. The upper differential adjustment mechanism of a lockstitch sewing machine according to claim 1, 2, 3 or 4, characterized in that: The sliding groove (6) is U-shaped, the cross section of the groove bottom of the sliding groove (6) is semicircular, and the groove walls on both sides of the sliding groove (6) are parallel.

6. The upper differential adjustment mechanism of a lockstitch sewing machine according to claim 5, characterized in that: The notch of the sliding groove (6) is arranged upward.

7. The upper differential adjustment mechanism of a lockstitch sewing machine according to claim 5, characterized in that: A notch (8) is provided at the connection between the groove bottom and the groove wall of the sliding groove (6).

8. An upper differential adjustment mechanism for a lockstitch sewing machine according to claim 1, 2, 3 or 4, characterized in that: The sliding groove (6) is annular in shape, the cross-sections of the groove bottoms at both ends of the sliding groove (6) are semicircular, and the groove walls on both sides of the sliding groove (6) are parallel.

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