Automatic adjusting mechanism for presser foot of sewing machine

Abstract

The invention relates to a sewing machine presser foot automatic adjusting mechanism which comprises a machine head shell, a machine needle rod and a presser foot rod are arranged on the machine head shell, the machine needle rod is connected with a driving main shaft through a crankshaft and a connecting rod, the upper portion of the presser foot rod is hinged to the output end of an adjusting lever, and a fulcrum in the middle of the adjusting lever is movably connected with a presser foot rod height adjusting mechanism. The presser foot rod height adjusting mechanism adjusts the height of the presser foot rod by changing the vertical position of a fulcrum in the middle of an adjusting lever, and the input end of the adjusting lever is movably connected with the swing driving mechanism. The swing driving mechanism is driven by the driving main shaft, the swing driving mechanism and the machine needle rod are driven by the driving main shaft, so that the machine needle rod and the presser foot rod are kept synchronous, the height of the presser foot can be adjusted, the swing amplitude of the presser foot can be adjusted, the height of the presser foot can be adjusted according to sewing materials with different thicknesses, and the sewing efficiency is improved. The swing amplitude of the presser foot can be adjusted according to multiple layers of sewing materials with different bulkiness, so that stitches are more matched with fabric materials, and the sewn stitches are more attractive.

Description

Technical Field

[0001] The invention relates to sewing machine technology, in particular to an automatic presser foot regulating mechanism for a sewing machine. Background Art

[0002] The presser foot swings synchronously with the needle machine when working. The presser foot swings up and down and cooperates with the teeth under the needle plate to push the fabric. Since the thickness of the fabrics sewn by the sewing machine is inconsistent, the current practice is to adjust the pressure of the presser foot. However, when sewing fabrics of bulky materials such as down jackets, the presser foot with this pressure adjustment method cannot be adjusted in height and swing amplitude because the thickness of the bulky fabrics after compression varies greatly compared to the natural state. This causes the stitches to not fit the material completely, the stitches are not beautiful, and the sewing effect is not ideal. Summary of the invention

[0003] The purpose of the present invention is to provide an automatic adjustment mechanism for the presser foot of a sewing machine, which can adjust the height of the presser foot and the swing amplitude of the presser foot. The height of the presser foot can be adjusted according to sewing materials of different thicknesses, and the swing amplitude of the presser foot can be adjusted according to sewing materials of multiple layers with different bulkiness, so that the stitches are more consistent with the fabric material and the sewn stitches are more beautiful.

[0004] To achieve the above purpose, the following technical solutions are adopted: A sewing machine presser foot automatic adjustment mechanism comprises a machine head housing, on which a needle bar and a presser foot bar are arranged, the needle bar is connected to a driving spindle via a crankshaft and a connecting rod, and is characterized in that: the upper portion of the presser foot bar is hinged to the output end of an adjusting lever, the fulcrum in the middle of the adjusting lever is movably connected to a presser foot bar height adjustment mechanism, the presser foot bar height adjustment mechanism adjusts the height of the presser foot bar by changing the upper and lower positions of the fulcrum in the middle of the adjusting lever, and the input end of the adjusting lever is movably connected to a swing amplitude driving mechanism; the swing amplitude driving mechanism is driven by a driving spindle, and the swing amplitude driving mechanism and the needle bar are both driven by the driving spindle, so that the needle bar and the presser foot bar remain synchronized.

[0005] The presser foot rod height adjustment mechanism includes a rocker arm, a lifting arm and a lifting motor. The connecting end of the rocker arm is hinged on the machine head housing, the driving end of the rocker arm is movably connected to the middle part of the adjusting lever, the middle part of the adjusting lever or the driving end of the rocker arm is also movably connected to the connecting seat, the lifting arm is longitudinally arranged, the connecting seat is arranged at the lower end of the lifting arm, the upper part of the lifting arm is connected to the driving motor arranged on the machine head housing, the driving motor drives the lifting arm to rise or fall, and then the lifting and lowering of the presser foot rod is realized through the rocker arm and the adjusting lever.

[0006] The upper part of the lifting arm longitudinally passes through the guide through hole of the head shell to keep the lifting arm longitudinally set, and a spring is set on the lower part of the lifting arm. The lower end of the spring abuts on the connecting seat, and the upper end abuts on the lower end of the guide through hole. The spring applies a downward force to the connecting seat; the side wall of the upper part of the lifting arm located above the guide through hole is provided with a tooth pattern, and the tooth pattern is meshed with the driving gear on the output shaft of the lifting motor.

[0007] The swing amplitude driving mechanism includes a swing amplitude driving shaft arranged in parallel with the driving main shaft, the output end of the swing amplitude driving shaft is movably connected to the input end of the adjusting lever through the output swing arm and the connecting rod, and the swing amplitude connecting seat is also fixedly connected to the swing amplitude driving shaft, the input end of the swing amplitude connecting seat is movably connected to the output end of the input swing arm, the input end of the input swing arm is hinged to the output end of the crank connecting rod, the hinged part is connected to the swing amplitude adjusting mechanism, the crank connecting rod is sleeved on the cam of the driving main shaft, and the swing amplitude adjusting mechanism can change the distance between the hinged part and the swing amplitude driving shaft.

[0008] The swing amplitude adjustment mechanism includes a swing amplitude drive motor and an adjustment seat. The adjustment seat is pivotally connected to the machine head housing, and the axial direction of the adjustment seat pivot is parallel to the driving main shaft. The swing amplitude drive motor drives the adjustment seat to rotate, and the output end of the adjustment seat is movably connected to the hinged part of the input swing arm and the crank connecting rod through the adjustment connecting rod.

[0009] The present invention can freely adjust the height of the presser foot rod through the lifting motor via the rocker arm, the lifting arm and the adjusting lever; on the other hand, since the movement amplitude of the crank connecting rod is fixed, and the swing amplitude driving motor changes the distance between the input swing arm and the hinged part of the crank connecting rod and the swing amplitude driving shaft through the adjusting seat and the adjusting connecting rod, the change in the distance between the hinged part and the swing amplitude driving shaft causes the crank connecting rod to drive the swing amplitude driving shaft to change the rotation angle, and then the swing amplitude driving shaft drives the adjusting lever to change the swing amplitude through the output swing arm and the connecting rod, thereby realizing the adjustment of the swing amplitude of the presser foot. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a schematic diagram of the internal structure of the present invention (I); Figure 3 It is a schematic diagram of the internal structure of the present invention (II); Figure 4 It is a schematic diagram of the internal structure of the present invention (III); Figure 5 It is a structural schematic diagram of the swing amplitude adjustment mechanism and the swing amplitude input mechanism of the present invention (I); Figure 6 It is a structural schematic diagram of the swing amplitude adjustment mechanism and the swing amplitude input mechanism of the present invention (II); Figure 7It is a structural schematic diagram of the presser foot rod height adjustment mechanism of the present invention; Figure 8 It is a structural schematic diagram of the swing amplitude driving mechanism of the present invention. Implementation

[0011] like Figure 1-8 As shown, an automatic presser foot adjustment mechanism for a sewing machine comprises a head housing 1, on which a needle bar 2 and a presser foot bar 3 are arranged, the needle bar 1 is connected to a driving spindle 5 via a crankshaft 4 and a connecting rod, the upper portion of the presser foot bar 3 is hinged to the output end of an adjusting lever 6, a fulcrum 61 in the middle of the adjusting lever 6 is movably connected to a presser foot bar height adjustment mechanism, the presser foot bar height adjustment mechanism adjusts the height of the presser foot bar 3 by changing the upper and lower positions of the fulcrum 61 in the middle of the adjusting lever, the input end of the adjusting lever 6 is movably connected to a swing amplitude driving mechanism; the swing amplitude driving mechanism is driven by the driving spindle 5, the swing amplitude driving mechanism and the needle bar are both driven by the driving spindle 5, so that the needle bar 2 and the presser foot bar 3 remain synchronized.

[0012] The presser foot bar height adjustment mechanism comprises a rocker arm 71, a lifting arm 72 and a lifting motor 73. The connecting end of the rocker arm 71 is hinged on the machine head housing 1. The driving end of the rocker arm 71 is movably connected to the middle part of the adjusting lever 6. The fulcrum 61 of the adjusting lever or the driving end of the rocker arm 71 is also movably connected to the connecting seat 74. The lifting arm 72 is longitudinally arranged, and the connecting seat 74 is arranged at the lower end of the lifting arm 72. The upper part of the lifting arm 72 longitudinally passes through the guide through hole of the machine head housing 1 to keep the lifting arm longitudinally arranged. The lower part of the lifting arm 72 is sleeved with a spring 75, the lower end of the spring 75 abuts on the connecting seat 74, and the upper end abuts on the lower end of the guide through hole. The spring 75 applies a downward force to the connecting seat 74; the upper part of the lifting arm 72 is provided with a tooth pattern on the side wall above the guide through hole, and the tooth pattern is meshed with the driving gear on the output shaft of the lifting motor 73. The driving motor 73 drives the lifting arm 72 to rise or fall, and then the lifting and lowering of the presser foot bar 3 is realized through the rocker arm 71 and the adjusting lever 6.

[0013] The swing amplitude driving mechanism includes a swing amplitude driving shaft 81 arranged parallel to the driving main shaft 5, the output end of the swing amplitude driving shaft 81 is movably connected to the input end of the adjusting lever 6 through the output swing arm 82 and the connecting rod, and a swing amplitude connecting seat 83 is also fixedly connected to the swing amplitude driving shaft 81, the input end of the swing amplitude connecting seat 83 is movably connected to the output end of the input swing arm 84, the input end of the input swing arm 84 is hinged to the output end of the crank connecting rod 85, the hinged part is connected to the swing amplitude adjusting mechanism, the crank connecting rod 85 is sleeved on the cam 51 of the driving main shaft 5, the swing amplitude adjusting mechanism includes a swing amplitude driving motor 91 and an adjusting seat 92, the adjusting seat 92 is pivotally connected to the machine head housing 1, and the axial direction of the pivot of the adjusting seat 92 is parallel to the driving main shaft 5, the swing amplitude driving motor 91 drives the adjusting seat 92 to rotate, and the output end of the adjusting seat 92 is movably connected to the hinged part of the input swing arm 84 and the crank connecting rod 85 through the adjusting connecting rod 93, and the swing amplitude adjusting mechanism can change the distance between the hinged part and the swing amplitude driving shaft 5.

[0014] When the present invention is working, the lifting motor drives the lifting arm to rise or fall, the lifting arm drives the rocking arm to swing up and down, the rocking arm drives the adjusting lever to move up and down, the lifting motor is controlled by the electronic control of the sewing machine, and the electronic control automatically controls the lifting height according to the set program for different fabrics, thereby realizing automatic adjustment of the height of the presser foot rod.

[0015] On the other hand, the present invention also adds a swing drive mechanism for the presser foot, which is driven by a driving spindle, thereby ensuring that the swing frequency of the presser foot is synchronized with the frequency of the needle bar; at the same time, the swing drive motor is used to drive the adjustment seat to rotate. When the adjustment seat rotates, the position of the hinged part of the input swing arm and the crank connecting rod can be changed by adjusting the connecting rod. The change in the position of the hinged part changes the distance between the hinged part and the swing drive shaft. Since the movement amplitude of the crank connecting rod is fixed, the change in the distance between the hinged part and the swing drive shaft changes the rotation angle of the crank connecting rod driven swing drive shaft. The distance between the hinged part and the swing drive shaft becomes larger, and the rotation angle of the swing drive shaft becomes smaller. Conversely, the distance between the hinged part and the swing drive shaft becomes smaller, and the rotation angle of the swing drive shaft becomes larger. Then, the swing amplitude of the swing drive shaft drives the adjusting lever through the output swing arm and the connecting rod, and the swing amplitude of the presser foot is also changed accordingly, thereby realizing the adjustment of the swing amplitude of the presser foot.

[0016] The swing amplitude of the presser foot is variable. When sewing bulky fabrics such as down, the swing amplitude of the presser foot is automatically adjusted according to the bulkiness. In conjunction with the electronic control of the sewing machine, the height and swing amplitude of the presser foot can be adjusted in real time.

Claims

1. A sewing machine presser foot automatic adjustment mechanism, comprising a machine head housing (1), a machine needle bar (2) and a presser foot bar (3) being arranged on the machine head housing (1), the machine needle bar (1) being connected to a driving spindle (5) via a crankshaft (4) and a connecting rod, characterized in that: The upper portion of the presser foot rod (3) is hinged to the output end of the adjusting lever (6); the fulcrum (61) in the middle of the adjusting lever (6) is movably connected to the presser foot rod height adjustment mechanism; the presser foot rod height adjustment mechanism adjusts the height of the presser foot rod (3) by changing the upper and lower positions of the fulcrum (61) in the middle of the adjusting lever; the input end of the adjusting lever (6) is movably connected to the swing amplitude driving mechanism; the swing amplitude driving mechanism is driven by the driving spindle (5); the swing amplitude driving mechanism and the needle rod are both driven by the driving spindle (5), so that the needle rod (2) and the presser foot rod (3) are kept synchronous.

2. The automatic adjustment mechanism for the presser foot of a sewing machine according to claim 1, characterized in that: The presser foot bar height adjustment mechanism comprises a rocker arm (71), a lifting arm (72) and a lifting motor (73); the connecting end of the rocker arm (71) is hinged on the machine head housing (1); the driving end of the rocker arm (71) is movably connected to the middle part of the adjustment lever (6); the fulcrum (61) of the adjustment lever or the driving end of the rocker arm (71) is also movably connected to a connecting seat (74); the lifting arm (72) is arranged longitudinally; the connecting seat (74) is arranged at the lower end of the lifting arm (72); the upper part of the lifting arm (72) is connected to a driving motor (73) arranged on the machine head housing (1); the driving motor (73) drives the lifting arm (72) to rise or fall, thereby realizing the lifting and lowering of the presser foot bar (3) through the rocker arm (71) and the adjustment lever (6).

3. The automatic adjustment mechanism for the presser foot of a sewing machine according to claim 2, characterized in that: The upper portion of the lifting arm (72) longitudinally passes through the guide through hole of the machine head housing (1) to keep the lifting arm longitudinally arranged. A spring (75) is sleeved on the lower portion of the lifting arm (72). The lower end of the spring (75) abuts against the connecting seat (74), and the upper end abuts against the lower end of the guide through hole. The spring (75) applies a downward force to the connecting seat (74). The upper portion of the lifting arm (72) is provided with a tooth pattern on the side wall above the guide through hole, and the tooth pattern is meshed with a driving gear on the output shaft of the lifting motor (73).

4. The automatic adjustment mechanism for the presser foot of a sewing machine according to claim 1, characterized in that: The swing amplitude driving mechanism comprises a swing amplitude driving shaft (81) arranged in parallel with the driving main shaft (5); the output end of the swing amplitude driving shaft (81) is movably connected to the input end of the adjusting lever (6) through an output swing arm (82) and a connecting rod; a swing amplitude connecting seat (83) is also fixedly connected to the swing amplitude driving shaft (81); the input end of the swing amplitude connecting seat (83) is movably connected to the output end of the input swing arm (84); the input end of the input swing arm (84) is hinged to the output end of a crank connecting rod (85); the hinged portion is connected to the swing amplitude adjusting mechanism; the crank connecting rod (85) is sleeved on a cam (51) of the driving main shaft (5); and the swing amplitude adjusting mechanism can change the distance between the hinged portion and the swing amplitude driving shaft (5).

5. The automatic adjustment mechanism for the presser foot of a sewing machine as claimed in claim 4, characterized in that: The swing amplitude adjustment mechanism comprises a swing amplitude drive motor (91) and an adjustment seat (92); the adjustment seat (92) is pivotally connected to the machine head housing (1), and the axial direction of the pivot of the adjustment seat (92) is parallel to the driving main shaft (5); the swing amplitude drive motor (91) drives the adjustment seat (92) to rotate, and the output end of the adjustment seat (92) is movably connected to the hinged part of the input swing arm (84) and the crank connecting rod (85) through the adjustment connecting rod (93).

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