Device for automatically adjusting stitch length and automatically lifting presser foot of sewing machine

Abstract

The utility model relates to the technical field of sewing equipment, and discloses an automatic stitch length adjusting and automatic presser foot lifting device of a sewing machine, which comprises a casing, a presser foot lifting mechanism C, a stitch length adjusting mechanism and a presser foot component, a motor is arranged on the casing, a cam is connected onto a rotating shaft of the motor, one end of the presser foot lifting mechanism C is a lifting roller, and the other end of the presser foot lifting mechanism C is a lifting roller. One end of the cam is a lifting roller, the other end of the cam is a presser foot lifting plate, the lifting roller is arranged above the cam and is in contact with the cam, the presser foot lifting plate is connected with the presser foot assembly, one end of the stitch length adjusting mechanism is provided with an eccentric wheel, the eccentric wheel is arranged on a rotating shaft of the motor, and the other end of the stitch length adjusting mechanism is connected with a feeding crank. The sewing machine can be driven by the motor to automatically adjust the stitch length and automatically lift the presser foot; the stitch length of the stitch of the sewing machine can be adjusted by setting the rotating angle of the motor; by setting the rotating speed of the motor, the sound is small and soft when the presser foot is automatically lifted, so that the sewing machine is more compact in structure and lower in cost.

Description

TECHNICAL FIELD

[0001] The utility model relates to sewing equipment technical field, concretely relates to automatic adjusting needle spacing and automatic lifting presser foot device of sewing machine. BACKGROUND

[0002] Most of the existing sewing machines use electromagnet as power source, and one electromagnet is needed to control the adjustment of needle spacing and automatic lifting of presser foot. When adjusting needle spacing, the needle spacing adjusting mechanism is driven by the extension and retraction of the electromagnet core. When lifting the presser foot, the lifting mechanism is driven by the extension and retraction of the electromagnet core. However, electromagnet has the disadvantages of unchangeable action speed and stroke, large noise, etc.

[0003] In the past two years, there has been a technology of lifting the presser foot by motor drive. However, the function is single, and one electromagnet is still needed to drive the adjustment of needle spacing, which is high in cost. In addition, since a large holding force is needed after the presser foot is lifted, a large power motor is needed to output, which is high in energy consumption. UTILITY MODEL CONTENTS

[0004] The technical problem to be solved by the utility model is the problem of large noise, unchangeable stroke and high cost of the power source for adjusting needle spacing and lifting presser foot.

[0005] In order to solve the above technical problem, the technical scheme of the utility model is to provide an automatic adjusting needle spacing and automatic lifting presser foot device of sewing machine, which comprises a machine shell, a lifting presser foot mechanism C, a needle spacing adjusting mechanism and a presser foot assembly. A motor is arranged on the machine shell. A cam is connected to the rotating shaft of the motor. One end of the lifting presser foot mechanism C is a lifting presser roller, and the other end is a presser foot lifting plate. The lifting presser roller is arranged above the cam and in contact with the cam. The presser foot lifting plate is connected with the presser foot assembly. One end of the needle spacing adjusting mechanism is provided with an eccentric wheel. The eccentric wheel is arranged on the rotating shaft of the motor. The other end of the needle spacing adjusting mechanism is connected with a feeding crank.

[0006] Optionally, the lifting presser foot mechanism C further comprises a lifting presser connecting plate, a ball, a connecting plate, a connecting top rod, a lifting presser lever, a lifting presser foot pull rod, a lifting presser foot front lever and a presser foot lifting plate. One end of the lifting presser connecting plate is hinged with the lifting presser roller. The ball is arranged on one end of the lifting presser connecting plate connected with the lifting presser roller, and the ball is hinged with the connecting plate. The connecting plate is a V-shaped plate placed horizontally, and the two ends of the opening are respectively hinged with the ball and the connecting top rod. The other end of the connecting top rod is hinged with the lifting presser lever. The other end of the lifting presser lever is hinged with the lifting presser foot pull rod. The other end of the lifting presser foot pull rod is hinged with the lifting presser foot front lever. The other end of the lifting presser foot front lever is hinged with the presser foot lifting plate. The other end of the presser foot lifting plate is connected with the presser foot assembly.

[0007] Optionally, the rotating center of the V-shaped connecting plate is hinged with a shaft position screw fixedly connected with the machine shell, the rotating center of the V-shaped connecting plate is the rotating center of the V-shaped connecting plate, and the rotating center of the V-shaped connecting plate is hinged with a lever shaft position screw fixedly connected with the machine shell, the rotating center of the V-shaped connecting plate is hinged with a lever screw pin fixedly connected with the machine shell, and the rotating center of the V-shaped connecting plate is hinged with a lever screw pin fixedly connected with the machine shell.

[0008] Optionally, the cam is composed of a circular arc segment concentric with the rotating center of the cam, a parabolic segment, and a curved surface segment connecting the circular arc segment and the parabolic segment.

[0009] Optionally, the presser foot assembly comprises a presser bar guide, a presser bar, a movable presser foot component, a presser bar shaft sleeve, a pressure adjusting spring, and a pressure adjusting screw, the presser bar guide is connected with the presser foot lifting plate, one end of the presser bar is connected with the presser bar guide, the other end of the presser bar passes through the presser bar shaft sleeve and is connected with the movable presser foot component, the presser bar shaft sleeve is fixed on the machine shell, the presser bar is slidable along the presser bar shaft sleeve, the lower end of the pressure adjusting spring is connected with the upper end of the presser bar, the upper end of the pressure adjusting spring is connected with the pressure adjusting screw, the upper end of the pressure adjusting screw is fixed on the machine shell, and the pressure adjusting spring is in a pressure state.

[0010] Optionally, a finger protector is arranged on the movable presser foot component.

[0011] Optionally, the eccentric wheel is hinged with an eccentric connecting rod below, the eccentric connecting rod is hinged with a swing plate seat below, the rotating center of the swing plate seat is hinged with a swing plate seat pin connected with the machine shell, the other end of the swing plate seat is hinged with a feeding short swing plate through a connecting pin, the other end of the feeding short swing plate is hinged with a feeding connecting rod and a feeding long swing plate through a connecting pin, the other end of the feeding connecting rod is connected with a feeding motor, and the other end of the feeding long swing plate is hinged with a feeding crank.

[0012] In summary, the sewing machine adopts a motor as a driving source for automatically adjusting the needle spacing and automatically lifting the presser foot, and the motor driving can realize the automatic adjustment of the needle spacing and the automatic lifting of the presser foot of the sewing machine; the rotating angle of the motor can be set to adjust the size of the stitch spacing of the sewing machine; the motor rotating speed can be set to make the automatic lifting and lowering of the presser foot be soft and low in sound; the operator can adjust the lifting speed of the presser foot according to the working rhythm and the lifting height of the presser foot according to the thickness of the sewing material, so as to improve the efficiency; the motor rotating speed can be adjusted to realize the soft lifting of the presser foot without damaging the easily damaged sewing material, and the motor can be used to adjust the needle spacing and lift the presser foot, so that the structure of the sewing machine is more compact and the cost is lower. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is a schematic structural view of the automatic needle spacing adjustment and automatic presser foot lifting device of the sewing machine.

[0014] Figure 2The utility model relates to an automatic needle spacing adjusting and automatic presser foot lifting device for a sewing machine.

[0015] Figure 3 The utility model relates to an automatic needle spacing adjusting and automatic presser foot lifting device for a sewing machine.

[0016] Figure 4 The utility model relates to an automatic needle spacing adjusting and automatic presser foot lifting device for a sewing machine.

[0017] Figure 5 The utility model relates to an automatic needle spacing adjusting and automatic presser foot lifting device for a sewing machine.

[0018] Figure 6 The utility model relates to an automatic needle spacing adjusting and automatic presser foot lifting device for a sewing machine.

[0019] Figure 7 The utility model relates to an automatic needle spacing adjusting and automatic presser foot lifting device for a sewing machine.

[0020] In the figure: 1, the casing; 2, motor; 3, cam; 4, lift pressure roller; 5, shaft position screw; 6, lift pressure connecting plate; 7, ball; 8, connecting plate; 9, rear lever shaft position screw; 10, connecting top rod; 11, lift pressure lever; 12, rear lever threaded pin; 13, lift pressure foot pull rod; 14, front lever threaded pin; 15, lift pressure foot front lever; 16, presser foot lifting plate; 17, presser bar guide frame; 18, presser bar shaft sleeve; 19, presser bar; 20, live presser foot part; 21, finger protector; 22, pressure adjusting spring; 23, pressure adjusting screw; 24, eccentric wheel; 25, eccentric connecting rod; 26, swing plate seat; 27, swing plate seat pin; 28, feeding short swing plate; 29, feeding connecting rod; 30, feeding long swing plate; 31, feeding crank; 32, connecting pin one; 33, connecting pin two. DETAILED DESCRIPTION

[0021] The following will be further explained in detail. Figures 1-7 The utility model will be further explained in detail.

[0022] The utility model discloses an automatic needle spacing adjusting and automatic presser foot lifting device for a sewing machine, referring to Figure 1, including the shell 1, the lifting presser foot mechanism C, the needle spacing adjusting mechanism and the presser foot assembly, the shell 1 is provided with the motor 2, the rotating shaft of the motor 2 is connected with the cam 3, one end of the lifting presser foot mechanism C is the lifting presser roller 4, the other end is the presser foot lifting plate 16, the lifting presser roller 4 is arranged above the cam 3 and is in tangential contact with the cam 3, the presser foot lifting plate 16 is connected with the presser foot assembly, one end of the needle spacing adjusting mechanism is provided with the eccentric wheel 24, the eccentric wheel 24 is arranged on the rotating shaft of the motor 2, the other end of the needle spacing adjusting mechanism is connected with the feeding crank 31.

[0023] In further embodiments, referring to Figure 3 and Figure 4 , the lifting presser foot mechanism C further comprises the lifting presser connecting plate 6, the ball 7, the connecting plate 8, the connecting top rod 10, the lifting presser lever 11, the lifting presser foot pull rod 13, the lifting presser foot front lever 15 and the presser foot lifting plate 16, one end of the lifting presser connecting plate 6 is hinged with the lifting presser roller 4, the rotating center of the lifting presser connecting plate 6 is hinged with the shaft position screw 5 which is fixedly connected with the shell 1, the ball 7 is arranged on one end of the lifting presser connecting plate 6 which is connected with the lifting presser roller 4, and the ball 7 is hinged with the connecting plate 8, the connecting plate 8 is a V-shaped plate which is horizontally arranged, the two ends of the opening of the V-shaped plate are respectively hinged with the ball 7 and the connecting top rod 10, the bending part of the V-shaped connecting plate 8 is the rotating center thereof, and the rotating center thereof is hinged with the lever shaft position screw 9 which is fixedly connected with the shell 1, the other end of the connecting top rod 10 is hinged with the lifting presser lever 11, the rotating center of the lifting presser lever 11 is hinged with the lever threaded pin 12 which is fixedly connected with the shell 1, the other end of the lifting presser lever 11 is hinged with the lifting presser foot pull rod 13, the other end of the lifting presser foot pull rod 13 is hinged with the lifting presser foot front lever 15, the rotating center of the lifting presser foot front lever 15 is hinged with the front lever threaded pin 14 which is fixedly connected with the shell 1, the other end of the lifting presser foot front lever 15 is hinged with the presser foot lifting plate 16, and the other end of the presser foot lifting plate 16 is connected with the presser foot assembly.

[0024] In further embodiments, referring to Figure 1 , the presser foot assembly comprises the presser rod guide 17, the presser rod 19, the movable presser foot part 20, the presser rod shaft sleeve 18, the pressure adjusting spring 22 and the pressure adjusting screw 23, the presser rod guide 17 is connected with the presser foot lifting plate 16, one end of the presser rod 19 is connected with the presser rod guide 17, the other end of the presser rod 19 passes through the presser rod shaft sleeve 18 and is connected with the movable presser foot part 20, the presser rod shaft sleeve 18 is fixed on the shell 1, the presser rod 19 can slide along the presser rod shaft sleeve 18, the lower end of the pressure adjusting spring 22 is connected with the upper end of the presser rod 19, the upper end of the pressure adjusting spring 22 is connected with the pressure adjusting screw 23, the upper end of the pressure adjusting screw 23 is fixed on the shell 1, the pressure adjusting spring 22 is in a compressed state, so that the movable presser foot part 20 is in a pressed state, and the finger protector 21 is arranged on the movable presser foot part 20.

[0025] In further embodiments, referring to Figure 2, eccentric wheel 24 below the articulated eccentric connecting rod 25, eccentric connecting rod 25 below the articulated swing plate seat 26, swing plate seat 26 rotating center hinge connected to the casing 1 on the swing plate seat pin 27, swing plate seat 26 the other end with the feeding short swing plate 28 through the connecting pin 32 hinge, feeding short swing plate 28 the other end with the feeding connecting rod 29 and feeding long swing plate 30 through the connecting pin 33 hinge, feeding connecting rod 29 the other end is connected with the feeding motor, feeding long swing plate 30 the other end with feeding crank 31 hinge.

[0026] In this embodiment, the cam 3 by a section with the center of the cam 3 concentric circle arc segment, parabolic segment and connecting arc segment and parabolic segment of the curved surface segment consists of, in the initial position, as shown in Figure 5 , the cam 3 as shown in Figure α angle position, eccentric wheel 24 as shown in Figure β angle position;

[0027] As shown in Figure 6 , when the work needs to be raised to the presser foot, the motor 2 spindle clockwise rotation λ angle, the cam 3 with the clockwise rotation λ angle, lifting the press roller 4 is lifted by the cam 3 to a certain height n, lifting the press plate 6 one end upward rotation, make the ball 7 with the connecting plate 8 upward rotation, through the connecting top rod 10 make lifting the press lever 11 the other end downward rotation, make the presser foot pull rod 13 with the presser foot front lever 15 rotation, thus make the presser foot lifting plate 16 rise, finally through the presser foot mechanism C with the presser foot 19 in the presser foot shaft sleeve 18 hole upward sliding, overcome the pressure of the pressure spring 22 to realize the presser foot action, the motor 2 reset, the presser foot 19 in the presser foot shaft sleeve 18 hole downward sliding to realize the presser foot down action;

[0028] As shown in Figure 7 , when the need to adjust the needle spacing, the motor 2 spindle counterclockwise rotation γ angle, eccentric wheel 24 with the counterclockwise rotation γ angle, through the eccentric connecting rod 25, swing plate seat 26 with the connecting pin 32 center of swing plate seat pin 27 to move a certain position, needle spacing adjustment action is completed connecting pin 32 position fixed, at this time the feeding eccentric wheel feeding connecting rod 29 is driven by the feeding motor up and down, and the feeding short swing plate 28 is hinged to the connecting pin 32, the other end of the feeding short swing plate 28 is hinged to the connecting pin 33, and the feeding long swing plate 30 is hinged to the feeding connecting rod 29 and the feeding long swing plate 30. The feeding connecting rod 29 moves up and down to drive the feeding short swing plate 28 to rotate up and down around the connecting pin 32. The connecting pin 33 also rotates up and down around the connecting pin 32 to drive the feeding long swing plate 30 to move and thus drive the feeding crank 31 to rotate. The feeding crank 31 rotates once for every stitch of the sewing machine. The feeding crank 31 can move the fabric forward. The greater the angle of rotation of the feeding crank 31, the greater the distance the fabric moves forward between each stitch, and the greater the needle spacing. By adjusting the position of the connecting pin 32, the angle of rotation of the feeding crank 31 can be adjusted, thereby achieving the purpose of adjusting the needle spacing.

[0029] When the feeding connecting rod 29 is at zero position (i.e. the middle position of the up and down moving distance), the angle between the feeding short swing plate 28 and the feeding long swing plate 30 is adjusted. When the feeding short swing plate 28 and the feeding long swing plate 30 are parallel, the up and down moving of the feeding connecting rod 29 drives the feeding crank 31 to rotate forward and backward with the same distance, and at this time, the needle pitch is zero. When the feeding connecting rod 29 is at zero position, the feeding short swing plate 28 and the feeding long swing plate 30 have an angle, and the feeding short swing plate 28 is above the feeding long swing plate 30. At this time, the up and down moving of the feeding connecting rod 29 drives the feeding crank 31 to rotate forward with a larger angle than that of rotating backward, and the needle pitch is increased. When the feeding connecting rod 29 is at zero position, the larger the angle between the feeding short swing plate 28 and the feeding long swing plate 30 is, the larger the difference between the angle of rotating forward and the angle of rotating backward of the feeding crank 31 driven by the up and down moving of the feeding connecting rod 29 is, and the larger the needle pitch is.

[0030] The cam 3 in the embodiment is a special-shaped cam. When the presser foot lifting action is performed, the cam 3 and the eccentric wheel 24 rotate simultaneously, and the presser foot lifting action and the needle pitch adjusting action are simultaneously performed. Since the presser foot lifting action is performed after the work is finished, the needle pitch adjusting action does not have an influence. When the needle pitch adjusting action is performed, the presser foot roller 4 moves on a section of the outer surface which is concentric with the rotation center of the cam, and the presser foot roller 4 will not be lifted, so that the presser foot mechanism will not be actuated, and the effect that only the needle pitch adjusting action is performed without the presser foot lifting action is achieved.

[0031] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. An automatic stitch length adjustment and automatic presser foot lifting device for a sewing machine, characterized in that, The device includes a housing (1), a presser foot lifting mechanism C, a stitch pitch adjustment mechanism, and a presser foot assembly. The housing (1) is equipped with a motor (2), and a cam (3) is connected to the shaft of the motor (2). One end of the presser foot lifting mechanism C is a presser foot lifting roller (4), and the other end is a presser foot lifting plate (16). The presser foot lifting roller (4) is located above the cam (3) and contacts the cam (3). The presser foot lifting plate (16) is connected to the presser foot assembly. One end of the stitch pitch adjustment mechanism is equipped with an eccentric wheel (24), which is located on the shaft of the motor (2). The other end of the stitch pitch adjustment mechanism is connected to a feeding crank (31).

2. The automatic stitch length adjustment and automatic presser foot lifting device for a sewing machine according to claim 1, characterized in that, The lifting foot mechanism C further includes a lifting connecting plate (6), a ball bearing (7), a connecting plate (8), a connecting rod (10), a lifting lever (11), a lifting foot pull rod (13), a lifting foot front lever (15), and a pressing foot lifting plate (16). One end of the lifting connecting plate (6) is hinged to the lifting roller (4). The ball bearing (7) is placed on the end of the lifting connecting plate (6) connected to the lifting roller (4), and the ball bearing (7) is hinged to the connecting plate (8). The connecting plate (8) is horizontal. The V-shaped structure is positioned so that a ball bearing (7) and a connecting rod (10) are respectively hinged at both ends of the opening. The other end of the connecting rod (10) is hinged to the lifting lever (11), the other end of the lifting lever (11) is hinged to the lifting foot pull rod (13), the other end of the lifting foot pull rod (13) is hinged to the lifting foot front lever (15), the other end of the lifting foot front lever (15) is hinged to the pressing foot lifting plate (16), and the other end of the pressing foot lifting plate (16) is connected to the pressing foot assembly.

3. The automatic stitch length adjustment and automatic presser foot lifting device for a sewing machine according to claim 2, characterized in that, The lifting and pressing connecting plate (6) is hinged at its rotation center with a shaft screw (5) that is fixedly connected to the housing (1). The bending point of the V-shaped connecting plate (8) is its rotation center, and a lever shaft screw (9) that is fixedly connected to the housing (1) is hinged at its rotation center. The lifting and pressing lever (11) is hinged at its rotation center with a lever threaded pin (12) that is fixedly connected to the housing (1). The front lever (15) of the lifting foot is hinged at its rotation center with a front lever threaded pin (14) that is fixedly connected to the housing (1).

4. The automatic stitch length adjustment and automatic presser foot lifting device for a sewing machine according to claim 2, characterized in that, The cam (3) consists of an arc segment concentric with the rotation center of the cam (3), a parabolic segment, and a curved surface segment connecting the arc segment and the parabolic segment.

5. The automatic stitch length adjustment and automatic presser foot lifting device for a sewing machine according to claim 2, characterized in that, The presser foot assembly includes a presser rod guide (17), a presser rod (19), a movable presser foot component (20), a presser rod bushing (18), a pressure adjusting spring (22), and a pressure adjusting screw (23). The presser rod guide (17) is connected to the presser foot lifting plate (16). One end of the presser rod (19) is connected to the presser rod guide (17), and the other end passes through the presser rod bushing (18) and is connected to the movable presser foot component (20). The presser rod bushing (18) is fixed on the housing (1). The presser rod (19) can slide along the presser rod bushing (18). The lower end of the pressure adjusting spring (22) is connected to the upper end of the presser rod (19). The upper end of the pressure adjusting spring (22) is connected to the pressure adjusting screw (23). The upper end of the pressure adjusting screw (23) is fixed on the housing (1). The pressure adjusting spring (22) is in a compressed state.

6. The automatic stitch length adjustment and automatic presser foot lifting device for a sewing machine according to claim 5, characterized in that, The movable presser foot component (20) is equipped with a finger guard (21).

7. The automatic stitch length adjustment and automatic presser foot lifting device for a sewing machine according to claim 1, characterized in that, An eccentric connecting rod (25) is hinged below the eccentric wheel (24), and a swing plate seat (26) is hinged below the eccentric connecting rod (25). A swing plate seat pin (27) connected to the housing (1) is hinged at the rotation center of the swing plate seat (26). The other end of the swing plate seat (26) is hinged to the feeding short swing plate (28) through connecting pin one (32). The other end of the feeding short swing plate (28) is hinged to the feeding connecting rod (29) and the feeding long swing plate (30) through connecting pin two (33). The other end of the feeding connecting rod (29) is connected to the feeding motor. The other end of the feeding long swing plate (30) is hinged to the feeding crank (31).

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