Thickness adjusting mechanism of sewing machine

Abstract

The invention relates to the field of sewing machines, in particular to a sewing machine thickness adjusting mechanism which comprises a feed dog frame, an eccentric shaft and an adjusting structure, the eccentric shaft comprises a rotating rod and an eccentric rod, the rotating rod is used for being rotatably connected to a machine body of a sewing machine around the axis of the rotating rod, and the eccentric rod is fixedly connected to the rotating rod and connected to the feed dog frame; the adjusting structure is used for driving the eccentric shaft to rotate so as to adjust the height of the feed dog frame, under the condition that the adjusting structure drives the eccentric shaft to rotate to a set position D, the highest point of the motion trail of the feed dog frame is lower than the needle plate, and under the condition that the adjusting structure drives the eccentric shaft to rotate to a set position G, the highest point of the motion trail of the feed dog frame is higher than the needle plate. The eccentricity of the eccentric shaft is increased, so that the feed dog frame can be always lower than the needle plate to realize tight sewing; under the condition that close sewing is not needed, the feed dog frame is made to be higher than the needle plate, the height of the feed dog frame higher than the needle plate can be adjusted according to the thickness of cloth, and the larger the thickness of the cloth is, the higher the height of the feed dog frame is.

Description

Technical Field

[0001] The present application relates to the field of sewing machines, and in particular to a thickness adjustment mechanism for sewing machines. Background Art

[0002] A sewing machine is a machine that uses one or more sewing threads to form one or more stitches on the sewing material to interweave or sew one or more layers of fabric together.

[0003] The feeding process of the sewing machine mainly relies on the reciprocating elliptical motion of the feed dog rack: the feed dog rack continuously lifts and pulls the fabric on the needle plate, thereby continuously dragging the fabric to be processed to the head of the machine.

[0004] The existing announcement document CN217298210U discloses a feed dog lifting mechanism and a sewing machine, which adjusts the height of the feed dog frame (including the differential tooth frame and the frame assembly) through an eccentric shaft. When sewing materials of different thicknesses, the sewing machine needs to drive the eccentric shaft to rotate through the adjustment structure to change the height of the feed tooth frame. Summary of the Invention

[0005] In order to change the height of the feed tooth frame, the present application provides a thickness adjustment mechanism for a sewing machine.

[0006] The present application provides a sewing machine thickness adjustment mechanism that adopts the following technical solutions: A thickness adjustment mechanism for a sewing machine includes a feed tooth frame, an eccentric shaft and an adjustment structure. The eccentric shaft includes a rotating rod and an eccentric rod. The rotating rod is used to rotate around its own axis and is connected to the body of the sewing machine. The eccentric rod is fixedly connected to the rotating rod, and the eccentric rod is connected to the feed tooth frame. The adjusting structure is used to drive the eccentric shaft to rotate to adjust the height of the feed tooth frame. When the adjusting structure drives the eccentric shaft to rotate to the set position D, the highest point of the motion trajectory of the feed tooth frame is lower than the needle plate. When the adjusting structure drives the eccentric shaft to rotate to the set position G, the highest point of the movement trajectory of the feed tooth frame is higher than the needle plate.

[0007] By adopting the above technical solution, the eccentricity of the eccentric shaft is increased, so that the feed tooth frame can always be lower than the needle plate to achieve close seams; When close stitching is not required, the feed dog frame is made higher than the needle plate, and the height of the feed dog frame above the needle plate can be adjusted according to the thickness of the fabric. The thicker the fabric, the higher the height of the feed dog frame should be adjusted.

[0008] Preferably, the adjustment structure includes a driving source, a connecting rod, a slider, a latch and a locking member. There are two connecting rods, one of which is provided with a sliding groove, and the slider is slidably embedded in the sliding groove. The latch is connected to the other connecting rod, the latch is embedded in the sliding groove, and the latch abuts against the slider. The locking member is used to fix the position of the slider in the slide groove. The two connecting rods are respectively connected to the output shaft of the driving source and the rotating rod.

[0009] By adopting the above technical solution, the driving source drives one connecting rod to rotate, the two connecting rods are hinged, and the other connecting rod rotates accordingly, thereby driving the eccentric shaft to rotate.

[0010] When the sewing machine is stopped, the presser foot is usually raised so that the fabric can be placed between the presser foot and the needle plate. At this time, the feed dog bracket needs to be lowered below the needle plate to prevent the feed dog bracket from damaging the fabric.

[0011] The adjustment structure repeatedly drives the eccentric shaft to rotate, and friction and wear between the pin and the slider cause the hinge axis between the two connecting rods to shift; at this time, the position of the slider is adjusted to reset the hinge axis, which is conducive to the adjustment structure driving the eccentric shaft to rotate accurately.

[0012] Preferably, the locking member comprises an adjusting screw, The adjusting screw is threadedly connected to the connecting rod, the axis of the adjusting screw is parallel to the sliding direction of the slider, and the end of the adjusting screw contacts the slider.

[0013] By adopting the above technical solution, the position of the slider is accurately adjusted to achieve locking between the connecting rod and the slider.

[0014] Preferably, the adjustment structure further includes a stop block and an elastic member. The stop block is slidably embedded in the slide groove, and the stop block is located on the side of the latch away from the slider. The elastic member is connected between the connecting rod and the stop block, and the elastic member causes the stop block to contact the latch.

[0015] By adopting the above technical solution, the latch is always in contact with the slider, so as to adjust the hinge axis and reset it.

[0016] Preferably, the slider includes a contact block, a short connecting rod, a long connecting rod and an adjustment block. The long connecting rod and the short connecting rod are both located between the contact block and the adjustment block. One end of the long connecting rod is rotatably connected to the contact block, one end of the short connecting rod is rotatably connected to the other end of the long connecting rod, and the other end of the short connecting rod is rotatably connected to the connecting rod. The rotation axis A between the long connecting rod and the contact block, the rotation axis B between the long connecting rod and the short connecting rod, and the rotation axis C between the short connecting rod and the connecting rod: Axis A, axis B, and axis C are parallel to each other, axis A is perpendicular to the sliding direction of the contact block, and axis B is located between axis C and the adjustment block. The distance AB between axis A and axis B, the distance BC between axis B and axis C: the distance AB is greater than the distance BC, The adjusting block is used to drive the short connecting rod to rotate. The latch pin abuts against the contact block, and the locking member is used to fix the position of the adjustment block in the sliding groove.

[0017] By adopting the above technical solution, the displacement of the adjustment block causes the short connecting rod to rotate about axis C and displace axis B (the displacement of axis B along the sliding direction of the adjustment block is equal to the displacement of the adjustment block). The displacement of axis B causes the long connecting rod to rotate about axis A and displace axis A (the displacement of axis A is less than the displacement of axis B along the sliding direction of the slider). The displacement of axis A causes the contact block to displace (the displacement of axis A is equal to the displacement of the contact block). The displacement of the contact block is smaller than that of the adjustment block, which is conducive to precise adjustment of the hinge axis reset.

[0018] Preferably, distance AB:distance BC≤2:1.

[0019] By adopting the above technical solution, the smaller the value of the distance AB: the distance BC, the smaller the value of the contact block displacement: the adjustment block displacement, which is conducive to the precise adjustment of the hinge axis reset.

[0020] Preferably, the surface BC coincides with the axis B and the axis C, and the angle between the surface BC and the sliding direction of the contact block is less than 45°.

[0021] By adopting the above technical solution, compared with the angle greater than 45°, the displacement of the contact block in this solution: the displacement of the adjustment block is smaller, which is conducive to precise adjustment of the reset of the hinge axis.

[0022] Preferably, the surface AC coincides with the axis A and the axis C. There are two long connecting rods and two short connecting rods, and the two long connecting rods and the two short connecting rods are symmetrical about the plane AC.

[0023] The adoption of the above technical solution is beneficial to force balance and moment balance.

[0024] Preferably, the locking member comprises a locking bolt. The axis of the locking bolt is perpendicular to the sliding direction of the adjusting block. The locking bolt is threadedly connected to the connecting rod. The locking bolt is used to tighten the adjusting block.

[0025] By adopting the above technical solution, locking between the connecting rod and the slider is achieved.

[0026] Preferably, the adjustment structure includes a driving source, a long rod and a short rod. The long rod is connected to the rotating rod, The short rod is rotatably connected to the long rod. The short rod is connected to the output shaft of the driving source.

[0027] By adopting the above technical solution, the rotation angle of the output shaft of the driving source is greater than the rotation angle of the eccentric shaft, which is conducive to driving the eccentric shaft to rotate accurately.

[0028] In summary, this application includes at least one of the following beneficial technical effects: 1. Increase the eccentricity of the eccentric shaft so that the feed tooth frame can always be lower than the needle plate to achieve tight seams; 2. When close stitching is not required, the feed rack is made higher than the needle plate. The height of the feed rack above the needle plate can be adjusted according to the thickness of the fabric. The thicker the fabric, the higher the height of the feed rack should be adjusted. 3. The adjustment structure repeatedly drives the eccentric shaft to rotate, causing friction and wear between the latch and the slider, resulting in the deviation of the hinge axis between the two connecting rods. By adjusting the position of the slider, the hinge axis is reset, which helps the adjustment structure drive the eccentric shaft to rotate accurately. 4. The displacement of the contact block is smaller than that of the adjustment block, which is conducive to precise adjustment of the hinge axis reset; 5. The rotation angle of the output shaft of the driving source is greater than the rotation angle of the eccentric shaft, which is conducive to driving the eccentric shaft to rotate accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the thickness adjustment mechanism of the sewing machine in Example 1.

[0030] Figure 2 This is a cross-sectional diagram of embodiment 2, a thickness adjustment mechanism of a sewing machine.

[0031] Figure 3 yes Figure 2 Enlarged view of point A in the middle.

[0032] Explanation of the accompanying reference numerals: 1. feed tooth frame; 2. eccentric shaft; 21. rotating rod; 22. eccentric rod; 3. adjusting structure; 31. driving source; 32. long rod; 33. short rod; 34. connecting rod; 341. slide groove; 35. latch; 36. slider; 361. contact block; 362. short connecting rod; 363. long connecting rod; 364. adjusting block; 37. locking member; 38. stop block; 39. elastic member. DETAILED DESCRIPTION

[0033] The present application is further described in detail below with reference to the accompanying drawings.

[0034] The embodiment of the present application discloses a thickness adjustment mechanism for a sewing machine.

[0035] Example 1 Reference Figure 1 The thickness adjustment mechanism of the sewing machine includes a feed tooth frame 1, an eccentric shaft 2 and an adjustment structure 3.

[0036] The feed dog frame 1 is used to be connected to the body of the sewing machine, and the feed dog frame 1 performs reciprocating elliptical motion relative to the body to realize feeding.

[0037] The eccentric shaft 2 includes a rotating rod 21 and an eccentric rod 22. The rotating rod 21 is used to rotate around its own axis and is connected to the body of the sewing machine. The eccentric rod 22 is fixedly connected to the rotating rod 21, and the eccentric rod 22 is connected to the feed tooth frame 1.

[0038] The adjusting structure 3 is used to drive the eccentric shaft 2 to rotate so as to adjust the height of the feed tooth frame 1 .

[0039] When the adjustment structure 3 drives the eccentric shaft 2 to rotate to the set position D, the highest point of the motion trajectory of the feed tooth frame 1 is lower than the needle plate. When the adjustment structure 3 drives the eccentric shaft 2 to rotate to the set position G, the highest point of the motion trajectory of the feed tooth frame 1 is higher than the needle plate.

[0040] Increasing the eccentricity of the eccentric shaft 2 allows the feed rack 1 to always be lower than the needle plate to achieve close seams. When close seams are not required, the feed rack 1 is made higher than the needle plate, and the height of the feed rack 1 above the needle plate can be adjusted according to the thickness of the fabric. The thicker the fabric, the higher the height of the feed rack 1 should be adjusted.

[0041] The adjustment structure 3 includes a driving source 31 , a long rod 32 and a short rod 33 .

[0042] The driving source 31 may be a stepping motor or a servo motor. The motor housing of the driving source 31 is fixedly connected to the body of the sewing machine, and the output shaft of the driving source 31 is parallel to the rotating rod 21 .

[0043] The long rod 32 is connected to the rotating rod 21, and the long rod 32 is perpendicular to the rotating rod 21. The short rod 33 is connected to the output shaft of the driving source 31, and the short rod 33 is perpendicular to the output shaft.

[0044] The short rod 33 is also rotatably connected to the long rod 32. Specifically, the adjustment structure 3 further includes a connecting rod 34 and a latch 35.

[0045] There are two connecting rods 34 , which are connected to the short rod 33 and the long rod 32 respectively.

[0046] One connecting rod 34 is provided with a sliding groove 341 ; a latch 35 is connected to the other connecting rod 34 , and the latch 35 is embedded in the sliding groove 341 to achieve relative rotation between the short rod 33 and the long rod 32 around the latch 35 .

[0047] The adjustment structure 3 further includes a slider 36 , a locking member 37 , a stop block 38 and an elastic member 39 .

[0048] The slider 36 and the stopper 38 are both slidably embedded in the slide groove 341 , and the latch 35 is located between the slider 36 and the stopper 38 .

[0049] A locking member 37 is connected between the connecting rod 34 and the slider 36 to secure the slider 36 in the slot 341. An elastic member 39 is connected between the connecting rod 34 and the stopper 38 to force the stopper 38 against the latch 35, which in turn forces the latch 35 against the slider 36. The elastic member 39 can be a spring.

[0050] In this embodiment, the locking member 37 includes an adjusting screw, which is threadedly connected to the connecting rod 34 , with the axis of the adjusting screw parallel to the sliding direction of the slider 36 , and the end of the adjusting screw abuts against the slider 36 .

[0051] The implementation principle of the thickness adjustment mechanism of a sewing machine in an embodiment of the present application is as follows: the adjustment structure 3 repeatedly drives the eccentric shaft 2 to rotate, and friction and wear between the pin 35 and the slider 36 cause the hinge axis between the two connecting rods 34 to shift; at this time, the position of the adjustment slider 36 is adjusted to reset the hinge axis, which is beneficial for the adjustment structure 3 to drive the eccentric shaft 2 to rotate accurately.

[0052] Example 2 The difference between this embodiment and embodiment 1 is that Reference Figure 2 The slider 36 includes a contact block 361, a short connecting rod 362, a long connecting rod 363 and an adjusting block 364. The contact block 361 abuts against the latch 35, and the adjusting block 364 is located on a side of the contact block 361 away from the latch 35.

[0053] The long connecting rod 363 and the short connecting rod 362 are both located between the contact block 361 and the adjustment block 364. One end of the long connecting rod 363 is rotatably connected to the contact block 361, one end of the short connecting rod 362 is rotatably connected to the other end of the long connecting rod 363, and the other end of the short connecting rod 362 is rotatably connected to the connecting rod 34.

[0054] The rotation axis A between the long connecting rod 363 and the contact block 361, the rotation axis B between the long connecting rod 363 and the short connecting rod 362, and the rotation axis C between the short connecting rod 362 and the connecting rod 34: the axis A, the axis B, and the axis C are parallel to each other, the axis A is perpendicular to the sliding direction of the contact block 361, and the axis B is located between the axis C and the adjustment block 364.

[0055] The distance AB between axes A and B, and the distance BC between axes B and C, satisfy the following relationship: 1:1 < distance AB: distance BC ≤ 2:1. Plane BC coincides with axes B and C, and the angle between plane BC and the sliding direction of contact block 361 is less than 45°. Plane AC coincides with axes A and C. Two long connecting rods 363 and two short connecting rods 362 are provided, and the two long connecting rods 363 and the two short connecting rods 362 are symmetrical about plane AC.

[0056] The sliding adjustment block 364 is used to drive the short link 362 to rotate.

[0057] The locking member 37 is used to fix the position of the adjustment block 364 in the slide groove 341. In this embodiment, the locking member 37 includes a locking bolt, the axis of which is perpendicular to the sliding direction of the adjustment block 364. The locking bolt is threadedly connected to the connecting rod 34 and is used to tighten the adjustment block 364.

[0058] It should be noted that the structure of the feed tooth frame 1 itself, the structure of the eccentric shaft 2 itself, and the connection structure between the eccentric shaft 2 and the feed tooth frame 1 do not belong to the improvements of this application, and the drawings are only for illustration.

[0059] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A thickness adjustment mechanism for a sewing machine, characterized in that: It includes a feed tooth frame (1), an eccentric shaft (2) and an adjustment structure (3). The eccentric shaft (2) comprises a rotating rod (21) and an eccentric rod (22). The rotating rod (21) is used to rotate around its own axis and is connected to the body of the sewing machine. The eccentric rod (22) is fixedly connected to the rotating rod (21), and the eccentric rod (22) is connected to the feed tooth frame (1). The adjusting structure (3) is used to drive the eccentric shaft (2) to rotate to adjust the height of the feed tooth frame (1). When the adjustment structure (3) drives the eccentric shaft (2) to rotate to the set position D, the highest point of the movement trajectory of the feed tooth frame (1) is lower than the needle plate. When the adjustment structure (3) drives the eccentric shaft (2) to rotate to the set position G, the highest point of the movement trajectory of the feed tooth frame (1) is higher than the needle plate.

2. The thickness adjustment mechanism of a sewing machine according to claim 1, characterized in that: The regulating structure (3) includes a driving source (31), a connecting rod (34), a slider (36), a latch (35) and a locking member (37). There are two connecting rods (34), one of which is provided with a sliding groove (341), and the slider (36) is slidably embedded in the sliding groove (341). The latch (35) is connected to the other connecting rod (34), the latch (35) is embedded in the sliding groove (341), and the latch (35) abuts against the slider (36). The locking member (37) is used to fix the position of the slider (36) in the slide groove (341). The two connecting rods (34) are respectively connected to the output shaft of the driving source (31) and the rotating rod (21).

3. The thickness adjustment mechanism of a sewing machine according to claim 2, characterized in that: The locking member (37) comprises an adjusting screw, The adjusting screw is threadedly connected to the connecting rod (34), the axis of the adjusting screw is parallel to the sliding direction of the slider (36), and the end of the adjusting screw abuts against the slider (36).

4. The thickness adjustment mechanism of a sewing machine according to claim 2, characterized in that: The regulating structure (3) further includes a stop block (38) and an elastic member (39). The stopper (38) is slidably embedded in the slide groove (341), and the stopper (38) is located on the side of the latch (35) facing away from the slider (36). The elastic member (39) is connected between the connecting rod (34) and the stop block (38), and the elastic member (39) causes the stop block (38) to contact the latch (35).

5. The thickness adjustment mechanism of a sewing machine according to claim 2, characterized in that: The slider (36) includes a contact block (361), a short connecting rod (362), a long connecting rod (363) and an adjustment block (364). The long connecting rod (363) and the short connecting rod (362) are both located between the contact block (361) and the adjustment block (364); one end of the long connecting rod (363) is rotatably connected to the contact block (361); one end of the short connecting rod (362) is rotatably connected to the other end of the long connecting rod (363); and the other end of the short connecting rod (362) is rotatably connected to the connecting rod (34). The rotation axis A between the long connecting rod (363) and the contact block (361), the rotation axis B between the long connecting rod (363) and the short connecting rod (362), and the rotation axis C between the short connecting rod (362) and the connecting rod (34): the axis A, the axis B, and the axis C are parallel to each other, the axis A is perpendicular to the sliding direction of the contact block (361), and the axis B is located between the axis C and the adjustment block (364). The distance AB between axis A and axis B, the distance BC between axis B and axis C: the distance AB is greater than the distance BC, The regulating block (364) is used to drive the short connecting rod (362) to rotate. The latch (35) abuts against the contact block (361), and the locking member (37) is used to fix the position of the adjustment block (364) in the slide groove (341).

6. The thickness adjustment mechanism of a sewing machine according to claim 5, characterized in that: Distance AB: Distance BC≤2:

1.

7. The thickness adjustment mechanism for a sewing machine according to claim 5, characterized in that: The surface BC coincides with the axis B and the axis C, and the angle between the surface BC and the sliding direction of the contact block (361) is less than 45 degrees.

8. The thickness adjustment mechanism for a sewing machine according to claim 5, characterized in that: The surface AC coincides with the axis A and the axis C. Two of the long connecting rods (363) and two of the short connecting rods (362) are provided, and the two long connecting rods (363) and the two short connecting rods (362) are symmetrical about the plane AC.

9. The thickness adjustment mechanism for a sewing machine according to claim 5, characterized in that: The locking member (37) comprises a locking bolt, The axis of the locking bolt is perpendicular to the sliding direction of the adjustment block (364), the locking bolt is threadedly connected to the connecting rod (34), and the locking bolt is used to tighten the adjustment block (364).

10. The thickness adjustment mechanism of a sewing machine according to claim 1, characterized in that: The regulating structure (3) includes a driving source (31), a long rod (32) and a short rod (33). The long rod (32) is connected to the rotating rod (21). The short rod (33) is rotatably connected to the long rod (32). The short rod (33) is connected to the output shaft of the driving source (31).

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