JP2016022382A - sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce expense required for assembling a pressure adjustment device and a lifting device.SOLUTION: A sewing machine 1 has at least one sewing foot 9 for pressing a cloth during sewing. A pressure adjustment device is used for presetting a pressing pressure applied to a cloth to be sewn when the cloth is pressed by the sewing foot. A lifting device is used for lifting up the sewing foot 9. The sewing machine has a common drive unit 12 for the pressure adjustment device and the lifting device. A cam disc 13, which cooperates with a cam lever 14 while lifting up the sewing foot 9 on one hand and driving the pressure adjustment device on the other hand, is arranged so as not to rotate on a driving shaft of the common drive unit. As a result, a sewing machine capable of reducing expense required for assembling the pressure adjustment device and the lifting device can be provided.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sewing machine.

  This type of sewing machine is known from US Pat. U.S. Pat. No. 6,057,051 discloses a sewing foot lifting device having a stepping motor, which cooperates with another component of the lifting device by means of a cam disk.

EP2105526B1 CN202653722U

  The object of the present invention is to reduce the expense in assembling the pressure regulating device and the lifting device.

  This problem is solved according to the invention by a sewing machine having the features disclosed in claim 1.

  According to the invention, it has been found that a common drive for the pressure regulating device on the one hand and for the lifting device on the other hand leads to a significant simplification of the sewing machine structure. The drive can be saved. Related control components can also be saved. The common drive can be designed so that it does not cause deterioration of the essentially independent functions “foot lifting” and “pressure regulation”. By saving the drive, the structure is more economical and more compact overall.

  The cooperation of the cam disk and the cam lever according to claim 2 results in a favorable separation and decoupling of the mechanical transmission element on the one hand for raising the foot and on the other hand for adjusting the pressure.

  The presetting of the cam lever position “minimum pressing pressure” according to claim 3 enables a predetermined preset of the minimum pressing pressure.

  The lifting shaft according to claim 4 allows the drive device to be arranged away from the sewing foot.

  The stepping motor according to claim 5 makes it possible in particular to preset the level and scale of the pressing pressure. This can be used to suit the respective sewing environment. Fine staging of the rising height is also advantageous. When sewing thick fabrics, a high rise height is pre-adjusted. When sewing thin fabrics, a lower rise height is pre-adjusted.

  The adjustment range according to claim 6 allows fine presetting of the pressing pressure without the requirement of too high positioning accuracy or step subdivision for the drive device.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

It is a figure which shows the sewing machine seen from the front perspectively. A pressure adjusting device for presetting the pressing pressure exerted on the fabric to be sewn by the sewing foot, a lifting device for raising the sewing foot, and a common driving device for these devices FIG. 2 is a perspective view of an assembly part of the sewing machine according to FIG. 1. FIG. 3 is a plan view of the assembly according to FIG. 2, viewed from the observation direction III, at the position “minimum pressing pressure”. It is a figure which shows the assembly components in the position "maximum foot rise" in the same figure as FIG. It is a figure which shows the assembly components in the position "maximum pressing pressure" in the same figure as FIG.

  The sewing machine 1 has a frame 2, an arm 3, and a head 4, and thus the sewing machine 1 having a C-type structure as a whole is made together with the base plate 5. An arm shaft (not shown in more detail) driven by the main drive device drives the needle bar 6 together with the sewing needle 7 fastened thereto to move up and down. The sewing needle 7 passes through the needle hole of the needle plate that forms a part of the support plate 8 that is the upper side surface of the base plate 5 of the sewing machine 1.

  The sewing machine 1 has a sewing foot 9 for pressing down a fabric to be sewn during sewing. This sewing foot is also called a presser foot. The sewing foot 9 is installed on the presser bar 10.

  The assembly part shown as a whole by reference numeral 11 in FIG. 2 is used to preset the pressing pressure exerted on the fabric when the sewing foot 9 presses the fabric to be sewn and to raise the sewing foot. The

  The assembly part 11 has a pressure adjusting device for presetting the pressing pressure, a lifting device for raising the sewing foot, and a common driving device for these two devices. The pressure regulating device and the lifting device will be described in detail below. The common drive device is configured as a stepping motor 12.

  The drive shaft of the stepping motor 12 is connected to the cam disk 13 so as not to rotate (being non-rotatable). The cam disk 13 cooperates with the cam lever 14 to raise the sewing foot 9 on the one hand and to drive the pressure adjusting device on the other hand. Similarly, the cam lever 14 is connected to the ascending shaft 15 so as not to rotate. The ascending shaft extends parallel to the arm shaft in the arm 3 of the sewing machine 1 and is rotatably installed on the frame of the sewing machine 1. Connected to the ascending shaft 15 so as not to rotate is an ascending lever 16 that is firmly coupled to the retaining bar 10 and cooperates with the retaining drive unit 17. The ascending shaft 15 is used to transmit the switch operating force from the cam lever 14 to the sewing foot 9.

  The ascending shaft 15 is eccentric with respect to the longitudinal axis of the ascending shaft at the end opposite to the cam lever 14 and is connected to the tension bar 18 in an articulated and connected manner. The tension bar is pressed against the presser bar 10 from above via a sleeve 19 in order to press the sewing foot 9 (not shown in FIG. 2).

  A compression spring 21 that spirally surrounds a part of the presser bar 10 is arranged between another sleeve 20 fixed to the frame and through which the presser bar 10 passes, and the presser drive unit 17.

  1 and 2 show the assembly part 11 in the drive position “minimum pressing pressure”. The cam bolt 22 of the cam lever 14 has moved to the cam recess 23 of the cam disk 13. The cam recess defines the cam lever position “minimum pressing pressure”. The tension bar 18 applies a minimum compressive force to the sleeve 19 in the associated pivot position of the lift shaft 15. The compression spring 21 is prestressed to a minimum. The force of the compression spring 21 is transmitted to the presser bar 10 by the presser drive unit 17, so that the minimum pressing pressure of the sewing foot 9 is generated during the operation of the sewing machine 1. In this driving position “minimum pressing pressure”, the raising lever 16 is separated from the pressing drive unit 17.

  FIG. 4 shows the drive position “maximum foot rise”. In order to reach this position, starting from the position “minimum pressing pressure” according to FIG. 3, the stepping motor 12 is actuated, whereby its drive shaft rotates about 300 ° counterclockwise from the field of view of FIGS. To do. Eventually, the cam bolt 22 advances on the cam disk 13 clockwise to the cam area 24. In this cam region, the cam disk 13 acts as a lever for the cam bolt 22. In this position, the raising lever 16 pushes the holding drive unit 17 upward in the direction of the sleeve 20 fixed to the frame, and lifts the sewing foot 9 by pulling the holding bar 10. At the same time, the tension bar 18 is in the inactive position.

  FIG. 5 shows the drive position “maximum pressing pressure”. Compared to FIG. 3, the stepping motor 12 is switched here, and its drive shaft rotates the cam disk 13 by about 210 ° clockwise compared to the position according to FIG. 3. In this case, the cam bolt 22 of the cam lever 14 advances on the cam disk 13 counterclockwise to the cam area 25 “maximum pressing pressure”. In this position, the tension bar 18 moves downward for an eccentric connection to the raising shaft 15 and correspondingly applies a tensile force to the sleeve 19. This is correspondingly pushed down to the maximum by the tension bar 18. Eventually, the compression spring 21 is prestressed to the maximum. As a result, there is a maximum pressing pressure that the presser bar 10 and hence the sewing foot 9 applies to the fabric to be sewn during the operation of the sewing machine 1. At this position “maximum pressing pressure”, the raising lever 16 is separated from the pressing drive unit 17.

  The cam disk 13 and cam lever 14 thus cooperate such that the raising of the sewing foot 9 occurs in one direction of rotation of the cam disk and the drive of the pressure regulator occurs in the opposite direction of rotation.

  The adjustment range of the drive shaft of the stepping motor 12 between the cam lever position “minimum pressing pressure” (see FIG. 3) and the cam lever position “maximum pressing pressure” (see FIG. 5) is larger than 180 °.

  The cam region 25 at the position “maximum pressing pressure” is also used as a collation / reference stopper for the stepping motor 12. For this purpose, the stepping motor 12 moves to the drive position “maximum pressing pressure” until the cam bolt 22 contacts the stopper formed in the cam area 25. The cam area 25 configured as a stopper does not require the use of a separate reference sensor. Otherwise, these reference sensors may be formed by light barriers or inductive switches.

  The stepping motor 12 may be started by an operator, for example, by a pedal of the sewing machine 1 for raising the foot (holding foot).

  In order to preset the pressing pressure, a prejustment may be performed by the control device 26 shown schematically in FIG. The controller 26 is in signal connection with the stepping motor 12 in a manner not shown in more detail.

1 sewing machine 9 sewing foot 12 common drive device 13 cam disk 14 cam lever

Claims (6)

At least one sewing foot (9) for holding down the fabric to be sewn during sewing;
A pressure adjusting device for presetting the pressing pressure exerted on the fabric when the sewing foot (9) presses the fabric to be sewn;
A raising device for raising the sewing foot (9);
A sewing machine (1) having a common drive (12) for the pressure regulating device and the lifting device,
A cam disk cooperating with a cam lever (14), on the one hand raising the sewing foot (9) and on the other hand a cam disk (13) for driving the pressure adjusting device, the common drive device (12) The sewing machine is arranged so as not to rotate on the drive shaft.   In the cam disk (13) and the cam lever (14), the sewing foot (9) rises in one rotation direction of the rotation of the cam disk (13), and the drive of the pressure adjusting device is driven by the cam. 2. Sewing machine according to claim 1, characterized in that it cooperates to occur in the opposite direction of rotation of the rotation of the disk (13).   The sewing machine according to claim 1 or 2, characterized in that the cam disk (13) has a cam recess (23) for presetting a cam lever position "minimum pressing pressure".   The sewing machine according to any one of claims 1 to 3, further comprising a rising shaft (15) for transmitting a switch operating force from the cam lever (14) to the sewing foot (9).   The sewing machine according to claim 1, wherein the common drive device is configured as a stepping motor. The adjustment range of the drive shaft of the common drive device (12) between the cam lever position "minimum pressing pressure" and the cam lever position "maximum pressing pressure" is greater than 180 °. The sewing machine according to any one of 5.

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