TWI681091B - Sewing machine - Google Patents

Abstract

A sewing machine has at least one sewing foot for holding down material to be sewn during sewing. A pressure adjusting device is used to preset a holding-down pressure, which the sewing foot exerts on the material to be sewn when holding it down. A lifting device is used to lift the sewing foot. The sewing machine has a common drive (12) for the pressure adjusting device and for the lifting device. A cam disc (13), which cooperates with a cam lever (14), on the one hand, to lift the sewing foot and, on the other hand, to drive the pressure adjusting device, is non-rotatably arranged on a drive shaft of the common drive. The result is a sewing machine with reduced construction outlay for the pressure adjusting device and the lifting device.

Description

Sewing machine Field of invention

The invention relates to a sewing machine.

Background of the invention

A sewing machine of this type is known from EP 2 105 526 B1. CN 202 658 372 U discloses a sewing foot lifting device with a stepping motor which cooperates with other elements of the lifting device through a cam disc.

Summary of the invention

The object of the present invention is therefore to reduce the expenditure for constructing the pressure regulating device and the lifting device.

This object is achieved by the sewing machine according to the invention, the sewing machine comprising: at least one sewing foot for pressing down the material to be sewn during sewing; a pressure adjusting device for presetting the pressing pressure, the sewing foot is pressed down When sewing the material, the pressing force is applied to the material to be sewn; a lifting device for lifting the sewing foot; a common driving device for the pressure adjusting device and for the lifting device, wherein, The cam disc is non-rotatably arranged on the drive shaft of the common drive device, the The cam disc cooperates with the cam lever to raise the sewing foot and drive the pressure adjusting device.

According to the invention, it is used for pressure regulating devices and for lifting equipment The built-in common drive significantly simplifies the construction of the sewing machine. The drive device can be saved. It can also save related control components. The common drive can be configured so as not to cause damage to the substantially independent functions of "foot lift" and "pressure adjustment". By saving the drive, the construction becomes more economical and overall more compact.

The cam disc and the cam lever cooperate in such a way that One direction of rotation of the cam disc is to lift the sewing foot, and the other direction of rotation of the cam disc is to drive the pressure adjusting device. Such cooperation may result in a foot lift and a pressure adjustment. Advantageous decoupling of mechanical transmission elements.

The "minimum depression pressure" is preset by the cam recess of the cam disc Force" cam lever position, which allows a predetermined minimum depression pressure to be preset.

The lifting shaft is used to transfer the cut from the cam lever to the sewing foot Change the operating force, which allows the driving device to be placed away from the sewing foot.

The drive device is configured as a stepper motor, which in particular allows Set the pressure level. This can be used to adapt to the corresponding sewing environment. It is also advantageous to increase the fine level of height. When sewing thick materials, a high lifting height can be pre-adjusted. When sewing thin materials, a low lifting height can be pre-adjusted.

The drive shaft of the common drive is at Adjustment between the position of the "force" cam lever and the position of the "maximum depression pressure" cam lever The range of joints is greater than 180°, which allows fine presetting of the pressing pressure without requiring too high positioning accuracy or subdivision of the driving phase.

1‧‧‧Sewing machine

2‧‧‧Frame

3‧‧‧arm

4‧‧‧ head

5‧‧‧ substrate

6‧‧‧Needle bar

7‧‧‧Needle

8‧‧‧Support plate

9‧‧‧Sewing feet

10‧‧‧Presser foot lever

11‧‧‧ Components

12‧‧‧Stepper motor

13‧‧‧Cam disc

14‧‧‧Cam lever

15‧‧‧lift shaft

16‧‧‧Lifting rod

17‧‧‧Pressure foot driver

18‧‧‧Tie rod

19, 20‧‧‧ Bush

21‧‧‧Compression spring

22‧‧‧Cam latch

23‧‧‧Cam recess

24, 25‧‧‧Cam area

26‧‧‧Control device

III‧‧‧Observation direction

In the following, embodiments of the invention will be explained in more detail with the aid of the drawings, in which: FIG. 1 shows a front view of a sewing machine in perspective; FIG. 2 shows an element of the sewing machine in perspective according to FIG. A pressure adjusting device for a pressing force, a lifting device for lifting the sewing foot, and a common driving device for these devices are provided, and the pressing force is applied to the material to be sewn when the material to be sewn is pressed by the sewing foot; 3 shows a plan view of the element according to FIG. 2 in the position of “minimum depression pressure” as viewed from the viewing direction III; FIG. 4 shows the component in the position of “maximum foot lift” in a view similar to FIG. 3; and FIG. 5 shows the components in the "maximum depression pressure" position in a perspective similar to FIG.

Detailed description of the preferred embodiment

The sewing machine 1 has a frame 2, an arm 3 and a head 4, which together with the base plate 5 form the overall C-shaped structure of the sewing machine 1. The arm shaft is driven by a main driving device not shown in detail, and the arm shaft drives the needle bar 6 on which the organic needle 7 is fixed to move up and down. The needle 7 passes through a needle hole in the needle plate, which here forms part of a support plate 8 which is the upper side of the base plate 5 of the sewing machine 1.

The sewing machine 1 has a sewing foot 9 to press down to be sewn during sewing Material, the sewing foot is also called presser foot. The sewing foot 9 is mounted on the presser foot bar 10.

In FIG. 2, the element generally indicated by reference numeral 11 is used for presetting Pressing pressure and lifting the sewing foot, which is applied by the sewing foot 9 to the material to be sewn while pressing the material to be sewn.

The assembly 11 includes a pressure regulating device for presetting down pressure The lifting device for lifting the sewing foot and the common driving device for the two devices. The pressure adjusting device and the lifting device will be described in detail below. The common driving device is configured as a stepping motor 12.

The drive shaft of the stepping motor 12 is non-rotatably connected to the cam disc 13. The cam disc 13 cooperates with the cam lever 14 to lift the sewing foot 9 and drive the pressure adjusting device. The cam lever 14 is non-rotatably connected to a lifting shaft 15 that extends parallel to the arm shaft in the arm 3 of the sewing machine 1 and is rotatably mounted on the frame of the sewing machine 1. The lifting lever 16 is non-rotatably connected to the lifting shaft 15, and the lifting lever 16 cooperates with the presser foot driver 17, which is rigidly connected to the presser foot lever 10. The lift shaft 15 is used to transmit a switching operation force from the cam lever 14 to the sewing foot 9.

The lifting shaft 15 is connected to the tie rod 18 in an articulated manner, the tie rod 18 At an end opposite to the cam lever 14, which is eccentric with respect to the longitudinal axis of the lift shaft, the tie bar presses the presser foot lever 10 from above through the bush 19 to press the sewing foot 9 not shown in FIG. 2.

The compression spring 21 is arranged on another bush 20 and the presser foot driver Between 17, the bush 20 is fixed to the frame and the presser foot rod 10 passes through the bush 20, and the compression spring 21 spirally surrounds a part of the presser foot rod 10.

Figures 1 and 2 show the group of "minimum depression pressure" drive position Piece 11. The cam latch 22 of the cam lever 14 has moved into the cam recess 23 of the cam plate 13, which defines the “minimum depression pressure” cam lever position. In the relevant pivot position of the lifting shaft 15, the tie rod 18 exerts a minimum compressive force on the bush 19. The compression spring 21 is pre-stressed to the minimum. The force of this compression spring 21 is transmitted by the presser foot drive 17 to the presser foot lever 10, so that a corresponding minimum pressing force of the sewing foot 9 is generated during the operation of the sewing machine 1. In this “minimum depression pressure” driving position, the lift lever 16 is disengaged from the presser foot driver 17.

Figure 4 shows the "maximum foot lift" drive position. To reach this position from the "minimum depression pressure" position of FIG. 3, the stepper motor 12 is operated to rotate its drive shaft through about 300° in a counterclockwise direction, as shown in FIGS. 3 and 4. The cam latch 22 thus moves in a clockwise direction on the cam disk 13 to the cam region 24 where the cam disk 13 acts as a lever on the cam latch 22. In this position, the lift lever 16 presses the presser foot driver 17 upward against the compression force of the compression spring 21 in the direction of the bush 20 fixed to the frame, and causes the presser foot lever 10 to lift the sewing foot 9. At the same time, the lever 18 is in an inactive (inactive) position.

Figure 5 shows the "maximum depression pressure" drive position. Compared to FIG. 3, the stepper motor 12 is changed to its drive shaft so that the cam disk 13-compared to the position according to FIG. 3-pivots clockwise by approximately 210°. In this case, the cam latch 22 of the cam lever 14 travels in the counterclockwise direction on the cam disk 13 to the "maximum depression pressure" cam region 25. In this position, the pull rod 18 moves downward due to the eccentric connection to the lift rod 15 and accordingly exerts a pulling force on the bush 19 which is correspondingly pressed down by the pull rod 18 to the greatest extent. Thus, the compression spring 21 It is prestressed to the greatest extent. As a result, the presser foot bar 10 and the sewing foot 9 exert the maximum pressing force on the material to be sewn during the operation of the sewing machine 1. In the "maximum depression pressure" position, the lift lever 16 is disengaged from the presser foot driver 17.

The cam disc 13 and the cam lever 14 therefore cooperate in such a way that the sewing feet The lifting of 9 is carried out in one direction of rotation of the cam disc, and the driving of the pressure regulating device is carried out in the other direction of rotation.

At the "minimum depression pressure" cam lever position (Figure 3) and "maximum The adjustment range of the drive shaft of the stepping motor 12 between the "depression pressure" cam lever position (FIG. 5) is greater than 180°.

In the "maximum depression pressure" position, the cam area 25 also serves as a stop So as to be used for positioning of the stepping motor 12. To this end, the stepper motor 12 moves to the "maximum depression pressure" drive position until the cam latch 22 rests on the stop formed by the cam area 25. The cam area 25 configured with a stop does not require the use of other positioning sensors that may be formed by a light barrier or an induction switch.

The stepping motor 12 may be driven by an operator through the pedal of the sewing machine 1 for foot lifting, for example.

To preset the depression pressure, pre-adjustment can be performed by the control device 26 schematically shown in FIG. 1. The control device 26 is signal-connected to the stepper motor 12 in a manner not specifically shown.

10‧‧‧Presser foot lever

11‧‧‧ Components

12‧‧‧Stepper motor

13‧‧‧Cam disc

14‧‧‧Cam lever

15‧‧‧lift shaft

16‧‧‧Lifting rod

17‧‧‧Pressure foot driver

18‧‧‧Tie rod

19, 20‧‧‧ Bush

21‧‧‧Compression spring

III‧‧‧Observation direction

Claims (5)

A sewing machine comprising: at least one sewing foot for pressing down a material to be sewn during sewing, and a pressure adjusting device for presetting a pressing pressure, the sewing foot lowers the material when pressing the material to be sewn A pressing force is applied to the material to be sewn, a lifting device for lifting the sewing foot, a common driving device for the pressure adjusting device and the lifting device, wherein a cam disk is non-rotatably arranged on the On the drive shaft of the common drive device, the cam disk cooperates with the cam lever, on the one hand to lift the sewing foot, on the other hand to drive the pressure adjustment device, the cam disk has a cam recess for pre Set the position of the "minimum depression pressure" cam lever. The sewing machine according to claim 1, wherein the cam disc and the cam lever cooperate in such a manner that the sewing foot is lifted in one rotation direction of the cam disc and along the cam disc The other direction of rotation drives the pressure regulating device. The sewing machine according to claim 1, characterized in that it includes a lifting shaft for transmitting a switching operation force from the cam lever to the sewing foot. The sewing machine according to claim 1, wherein the driving device is configured as a stepping motor. The sewing machine according to claim 1, wherein the adjustment range of the drive shaft of the common drive device between the "minimum depression pressure" cam lever position and the "maximum depression pressure" cam lever position is greater than 180°.

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