Automatic presser foot lifting mechanism of sewing machine

Abstract

The utility model provides an automatic presser foot lifting mechanism of a sewing machine, and belongs to the technical field of sewing machines. The automatic presser foot lifting mechanism solves the problems that an existing automatic presser foot lifting mechanism is low in stability and difficult to install. According to the automatic presser foot lifting mechanism of the sewing machine, the sewing machine comprises a machine shell, a pressing rod and a presser foot lifting part arranged at the lower end of the pressing rod, the automatic presser foot lifting mechanism comprises a lifting plate, an electromagnet fixed to the machine shell and a knee-controlled ejector rod capable of swinging, and the lifting plate is connected with the pressing rod and can drive the presser foot lifting part to move up and down. The upper end of the lifting plate is connected with a front lifting lever, the front lifting lever is rotationally connected to the machine shell, the electromagnet is connected with an electromagnet pushing connecting plate which is connected with the upper end of the front lifting lever and can drive the front lifting lever to rotate, the upper end of the knee-controlled ejector rod is connected with a rear lifting lever, and the machine shell is rotationally connected with the rear lifting lever. According to the automatic presser foot lifting mechanism of the sewing machine, the installation difficulty needed during connection is low, and installation is more convenient.

Description

Technical Field

[0001] The utility model belongs to the technical field of sewing machines and relates to an automatic presser foot lifting mechanism of a sewing machine. Background Art

[0002] The presser foot lifter of a sewing machine is either manually lifted or has a knee lift rod hinged on a lever, where the operator's knee acts on the knee lift rod to lift the presser foot.

[0003] For example, Chinese patent application [Authorization Announcement No.: CN109629127B] discloses a knee-rest presser foot lifting device for a sewing machine, the sewing machine includes a clamping rod and a small presser foot arranged at the lower end of the clamping rod, the clamping rod is sleeved with a clamping spring, the presser foot lifting device includes a front lifting lever that can drive the clamping rod to rise and a lifting pull rod that drives the front lifting lever to swing, the end of the lifting pull rod is connected to a lifting rear lever, the presser foot lifting device also includes an electromagnet that can drive the lifting rear lever to swing, a rotatable knee-controlled articulated shaft and a knee-rest plate that drives the knee-controlled articulated shaft to rotate, the output shaft of the electromagnet is connected to the middle part of the lifting rear lever through a pull rod crank, the end of the knee-controlled articulated shaft is connected to a rheostat, and the knee-controlled A limit frame is also connected to the articulated shaft, and a lifting assembly is provided between the limit frame and the rear lifting lever. The end of the lifting assembly is connected to the end of the rear lifting lever. The rheostat includes a shell, a connecting screw and a locking nut screwed on the connecting screw. The end of the knee-controlled hinge shaft is connected to one end of the connecting screw, and the other end of the connecting screw is fixed with an indicator needle. The shell is provided with a scale value, and the indicator needle corresponds to the scale value. When the knee-controlled hinge shaft changes and the sliding rod in the rheostat moves, the resistance R changes. According to I=U / R, it is concluded that the current I changes. The current is fed back to the electronic control of the sewing machine as a signal. The electronic control generates current to the electromagnet. The electromagnet generates thrust to drive the lifting rod to move.

[0004] The above structure uses an electromagnet as a knee-controlled power assist, but since the electromagnet is connected to the middle part of the rear lifting lever through a pull rod crank, and the front lifting lever of the clamping rod is connected to the lifting pull rod, and the end of the lifting pull rod is connected to the rear lifting lever, the pull rod crank of the electromagnet is directly connected to the rear lifting lever, and its force transmission path is long, resulting in low stability during the transmission process and great difficulty in installation. Utility Model Content

[0005] The purpose of the utility model is to solve the above problems in the existing technology and to propose an automatic presser foot lifting mechanism for a sewing machine. The technical problem to be solved by the utility model is: how to solve the problem that the existing automatic presser foot lifting mechanism has low stability and is difficult to install.

[0006] The purpose of the utility model can be achieved through the following technical solutions:

[0007] The lifting mechanism is characterized in that the upper end of the lifting plate is connected with a lifting front lever, the lifting front lever is rotatably connected to the casing, the electromagnet is connected with an electromagnet pushing connecting plate which is connected with the upper end of the lifting front lever and can drive it to rotate, the upper end of the knee-controlled push rod is connected with a lifting rear lever, the lifting rear lever is rotatably connected to the casing, one end of the lifting rear lever is connected with the upper end of the knee-controlled push rod, the other end of the lifting rear lever is connected with one end of the knee-controlled pull rod, and the other end of the knee-controlled pull rod is connected with the upper end of the lifting front lever and can drive it to rotate.

[0008] Working principle: when driving the presser foot lifter to move up and down, the existing knee plate is used to push the knee-controlled push rod laterally. When the knee-controlled push rod drives the front lifter to swing through the lifting rear lever and the knee-controlled pull rod, the front lifter is subjected to the force of the knee-controlled pull rod and drives the presser foot lifter to move up and down through the clamping rod. When used for a long time, the user often controls the presser foot lifter through his knee. In order to save effort, the present application also provides the use of an electromagnet to control the up and down movement of the presser foot lifter. It only needs to energize the electromagnet connected to the casing. The electromagnet is connected to an electromagnet-pushing connecting plate. The electromagnet-pushing connecting plate drives the front lifter to swing. At this time, the upper end of the front lifter is subjected to the pulling force of the electromagnet-pushing connecting plate, which makes the front lifter The lever is easier to swing, and the front lever is lifted to drive the presser foot to move up and down through the clamping rod, thereby realizing the up and down movement of the presser foot. The present application is achieved by providing an electromagnet to push a connecting plate and a knee-controlled pull rod. The electromagnet controls the up and down movement of the presser foot and the knee-controlled pull rod controls the up and down movement of the presser foot independently of each other. At this time, the action force of the electromagnet directly acts on the front lever through the electromagnet to push the connecting plate. Therefore, the action force of the electromagnet is directly transmitted to the front lever to be lifted. The force transmission path is shorter, which further improves the stability of the electromagnet's push. Moreover, the push of the electromagnet directly connects the electromagnet to push the connecting plate with the front lever to be lifted. Therefore, the installation difficulty required during the connection is lower, making the installation more convenient.

[0009] In the automatic presser foot lifting mechanism of the above-mentioned sewing machine, a waist-shaped hole is opened on the electromagnet pushing connecting plate, and the waist-shaped hole is arranged close to the lifting front lever. The lifting front lever has a connecting pin that passes through the waist-shaped hole and can slide along the waist-shaped hole.

[0010] The cooperation of the waist-shaped hole and the connecting pin ensures that when the knee-controlled pull rod is used, the movement of the lifting front lever will not affect the electromagnet, thereby preventing the electromagnet from being displaced by the lifting front lever when the electromagnet is not energized, thereby achieving an air avoidance effect.

[0011] In the automatic presser foot lifting mechanism of the above-mentioned sewing machine, the electromagnet has an output shaft, and the output shaft is connected to a fork-shaped crank that can swing under its drive. The casing is rotatably connected to a rotating shaft, one end of the rotating shaft is connected to the end of the fork-shaped crank, and the other end of the rotating shaft is connected to the electromagnet crank, and the electromagnet pushes the connecting plate to be connected to the electromagnet crank.

[0012] After the electromagnet is energized, the output shaft of the electromagnet extends out and drives the fork crank to rotate, the fork crank drives the rotating shaft to rotate, and the rotating shaft drives the electromagnet push plate and connecting plate to move through the electromagnet crank, thereby realizing the transmission of the electromagnet driving force and saving installation space.

[0013] In the automatic presser foot lifting mechanism of the sewing machine, the electromagnet pushes the middle part of the connecting plate to bend toward the direction of the knee control rod to form an escape portion, and the escape portion is located on one side of the knee control rod.

[0014] The setting of the avoidance part ensures that the electromagnet pushes the connecting plate without interfering with the casing, thereby playing an avoidance role and not affecting the installation and arrangement of other parts inside the casing. In addition, the strength of the electromagnet pushes the connecting plate can be enhanced by bending. The knee control rod and the electromagnet pushes the connecting plate at similar positions of the lifting front lever, which further improves the stability of the rotation of the lifting front lever.

[0015] In the automatic presser foot lifting mechanism of the above-mentioned sewing machine, the hinge between the electromagnet pushing the connecting plate and the lifting front lever is close to the hinge between the knee control rod and the lifting front lever, and the hinge between the lifting front lever and the casing is lower than the hinge between the electromagnet pushing the connecting plate and the lifting front lever and the hinge between the knee control rod and the lifting front lever.

[0016] The arrangement of this structure enables the electromagnet to push the connecting plate to quickly push and lift the upper end of the front lever, making the pushing of the electromagnet and the knee-controlled push rod more convenient, making the up and down movement of the presser foot lifter faster, and making the use of the automatic presser foot lifter mechanism more labor-saving.

[0017] In the automatic presser foot lifting mechanism of the sewing machine, the upper end of the clamping rod is fixedly locked with a presser rod guide frame, and the lower end of the lifting plate is slidably connected to the lower end of the presser rod guide frame.

[0018] The arrangement of this structure enables the lifting plate to drive the clamping rod to move via the clamping rod guide frame, and the clamping rod will not affect the position of the lifting plate when moving in the horizontal direction, thereby preventing the clamping rod from affecting the automatic presser foot lifting mechanism during normal use, ensuring that the presser foot can be lifted quickly while also ensuring that the normal use of the presser foot is not affected.

[0019] Compared with the prior art, the automatic presser foot lifting mechanism of the sewing machine has the following advantages: by providing an electromagnet pushing a connecting plate and a knee-controlled pull rod, the electromagnet controlling the up and down movement of the presser foot and the knee-controlled pull rod controlling the up and down movement of the presser foot are independent of each other, and at this time, the action force of the electromagnet directly acts on the lifting front lever through the electromagnet pushing the connecting plate, so the action force of the electromagnet is directly transmitted to the lifting front lever, and the force transmission path is short, which further improves the stability of the electromagnet push, and the push of the electromagnet directly connects the electromagnet pushing the connecting plate with the lifting front lever, so the installation difficulty required during the connection is low, making the installation more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the utility model after assembly.

[0021] Figure 2 It is one of the partial structural schematic diagrams of the utility model after assembly.

[0022] Figure 3 This is the second schematic diagram of the partial structure of the utility model after assembly.

[0023] In the figure, 1, casing; 2, clamping rod; 3, presser foot lifter; 4, lifting plate; 5, electromagnet; 51, electromagnet push connecting plate; 51a, avoidance part; 51b, waist-shaped hole; 52, output shaft; 53, fork-shaped crank; 54, rotating shaft; 55, electromagnet crank; 6, knee-controlled push rod; 61, lifting rear lever; 62, knee-controlled pull rod; 7, lifting front lever; 71, connecting pin; 8, pressure rod guide. DETAILED DESCRIPTION

[0024] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0025] like Figure 1 and Figure 2 As shown, the automatic presser foot lifting mechanism of the sewing machine comprises a casing 1, a clamping rod 2 and a presser foot lifting 3 arranged at the lower end of the clamping rod 2. The automatic presser foot lifting mechanism comprises a lifting plate 4, an electromagnet 5 fixed on the casing 1 and a swingable knee-controlled push rod 6. The lifting plate 4 is connected to the clamping rod 2 and can drive the presser foot lifting 3 to move up and down.

[0026] Specifically, Figure 1As shown, the upper end of the lifting plate 4 is connected with a lifting front lever 7, which is rotatably connected to the casing 1, and the electromagnet 5 is connected with an electromagnet pushing connecting plate 51 which is connected to the upper end of the lifting front lever 7 and can drive it to rotate, and the casing 1 is rotatably connected with a lifting rear lever 61, one end of the lifting rear lever 61 is connected to the upper end of the knee-controlled top rod 6, and the other end of the lifting rear lever 61 is connected to one end of the knee-controlled pull rod 62, and the other end of the knee-controlled pull rod 62 is connected to the upper end of the lifting front lever 7 and can drive it to rotate.

[0027] Working principle: when driving the presser foot lifter 3 to move up and down, the existing knee plate is used to push the knee-controlled push rod 6 laterally. When the knee-controlled push rod 6 drives the front lever 7 to swing by lifting the rear lever 61 and the knee-controlled pull rod 62, the front lever 7 is subjected to the force of the knee-controlled pull rod 62 and drives the presser foot lifter 3 to move up and down through the clamping rod 2. When used for a long time, the user will often control the presser foot lifter 3 through the knee. In order to save effort, the present application also provides the use of an electromagnet 5 to control the up and down movement of the presser foot lifter 3. It only needs to energize the electromagnet 5 connected to the casing 1. The electromagnet 5 is connected to an electromagnet pushing connecting plate 51. The electromagnet pushing connecting plate 51 drives the front lever 7 to swing. At this time, the upper end of the front lever 7 is subjected to the pulling force of the electromagnet pushing connecting plate 51, so that the lifting The front lever 7 is easier to swing. When the front lever 7 is lifted, it drives the presser foot 3 to move up and down through the clamping rod 2, thereby realizing the up and down movement of the presser foot 3. The present application is achieved by providing an electromagnet pushing connecting plate 51 and a knee-controlled pull rod 62. The electromagnet 5 controls the up and down movement of the presser foot 3 and the knee-controlled pull rod 62 controls the up and down movement of the presser foot 3 independently. At this time, the action force of the electromagnet 5 directly acts on the lifting front lever 7 through the electromagnet pushing connecting plate 51. Therefore, the action force of the electromagnet 5 is directly transmitted to the lifting front lever 7. The force transmission path is shorter, which further improves the stability of the push of the electromagnet 5. Moreover, the push of the electromagnet 5 directly connects the electromagnet pushing connecting plate 51 with the lifting front lever 7. Therefore, the installation difficulty required during connection is lower, making the installation more convenient.

[0028] like Figure 2 and Figure 3 As shown, the middle part of the electromagnet-pushed connecting plate 51 is bent toward the direction of the knee-controlled pull rod 62 to form an avoidance portion 51a, and the avoidance portion 51a is located on one side of the knee-controlled pull rod 62. The hinge between the electromagnet-pushed connecting plate 51 and the front lifting lever 7 is close to the hinge between the knee-controlled pull rod 62 and the front lifting lever 7. The upper end of the clamping rod 2 is fixedly locked with a pressure rod guide frame 8, and the lower end of the lifting plate 4 is slidingly connected to the lower end of the pressure rod guide frame 8. The hinge between the front lifting lever 7 and the casing 1 is lower than the hinge between the electromagnet-pushed connecting plate 51 and the front lifting lever 7 and the hinge between the knee-controlled pull rod 62 and the front lifting lever 7.

[0029] like Figure 2 and Figure 3As shown, a waist-shaped hole 51b is provided on the electromagnet-pushing connecting plate 51, and the waist-shaped hole 51b is arranged near the lifting front lever 7. The lifting front lever 7 has a connecting pin 71 which is penetrated in the waist-shaped hole 51b and can slide along the waist-shaped hole 51b. The electromagnet 5 has an output shaft 52, and a fork-shaped crank 53 which can swing under its drive is connected to the output shaft 52. A rotating shaft 54 ​​is rotatably connected to the casing 1, and one end of the rotating shaft 54 ​​is connected to the end of the fork-shaped crank 53, and the other end of the rotating shaft 54 ​​is connected to the electromagnet crank 55. The electromagnet-pushing connecting plate 51 is connected to the electromagnet crank 55.

[0030] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. An automatic presser foot lifting mechanism for a sewing machine, the sewing machine comprising a housing (1), a clamping rod (2) and a presser foot lifting mechanism (3) arranged at the lower end of the clamping rod (2), the automatic presser foot lifting mechanism comprising a lifting plate (4), an electromagnet (5) fixed on the housing (1) and a swingable knee-controlled push rod (6), the lifting plate (4) being connected to the clamping rod (2) and being able to drive the presser foot lifting mechanism (3) to move up and down, characterized in that: The upper end of the lifting plate (4) is connected to a front lifting lever (7), and the front lifting lever (7) is rotatably connected to the casing (1). The electromagnet (5) is connected to an electromagnet pushing connecting plate (51) which is connected to the upper end of the front lifting lever (7) and can drive it to rotate. The casing (1) is rotatably connected to a rear lifting lever (61), one end of the rear lifting lever (61) is connected to the upper end of the knee control top rod (6), the other end of the rear lifting lever (61) is connected to one end of a knee control pull rod (62), and the other end of the knee control pull rod (62) is connected to the upper end of the front lifting lever (7) and can drive it to rotate.

2. The automatic presser foot lifting mechanism of a sewing machine according to claim 1, characterized in that: The electromagnet push connecting plate (51) is provided with a waist-shaped hole (51b), the waist-shaped hole (51b) is arranged close to the lifting front lever (7), and the lifting front lever (7) has a connecting pin (71) which is penetrated in the waist-shaped hole (51b) and can slide along the waist-shaped hole (51b).

3. The automatic presser foot lifting mechanism of a sewing machine according to claim 1 or 2, characterized in that: The electromagnet (5) has an output shaft (52), and a fork-shaped crank (53) is connected to the output shaft (52) and can swing under the drive of the fork-shaped crank (53). The housing (1) is rotatably connected to a rotating shaft (54), one end of the rotating shaft (54) is connected to the end of the fork-shaped crank (53), and the other end of the rotating shaft (54) is connected to an electromagnet crank (55). The electromagnet pushes the connecting plate (51) to be connected to the electromagnet crank (55).

4. The automatic presser foot lifting mechanism of a sewing machine according to claim 1 or 2, characterized in that: The electromagnet pushes the middle portion of the connecting plate (51) to bend toward the direction of the knee control pull rod (62) to form an avoidance portion (51a), and the avoidance portion (51a) is located on one side of the knee control pull rod (62).

5. The automatic presser foot lifting mechanism of a sewing machine according to claim 1 or 2, characterized in that: The hinge point between the electromagnet-pushing connecting plate (51) and the lifting front lever (7) is close to the hinge point between the knee-control lever (62) and the lifting front lever (7), and the hinge point between the lifting front lever (7) and the casing (1) is lower than the hinge point between the electromagnet-pushing connecting plate (51) and the lifting front lever (7) and the hinge point between the knee-control lever (62) and the lifting front lever (7).

6. The automatic presser foot lifting mechanism of a sewing machine according to claim 1 or 2, characterized in that: The upper end of the pressing rod (2) is fixedly locked with a pressing rod guide frame (8), and the lower end of the lifting plate (4) is slidably connected to the lower end of the pressing rod guide frame (8).

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