CN108411504B

CN108411504B - Sewing machine

Info

Publication number: CN108411504B
Application number: CN201710073488.4A
Authority: CN
Inventors: 射越悠
Original assignee: Juki Corp
Current assignee: Juki Corp
Priority date: 2017-02-10
Filing date: 2017-02-10
Publication date: 2022-01-07
Anticipated expiration: 2037-02-10
Also published as: CN108411504A

Abstract

The cloth presser foot can be adjusted to any height. The disclosed device is provided with: a rotary peripheral cam (20); a driven body (31) that abuts the outer periphery of the outer peripheral cam; a transmission body (32) which rotates through the driven body and transmits the lifting motion to the cloth presser foot (11); a presser motor (14) for rotating the outer peripheral cam; and a control device (90) for controlling the presser foot motor and controlling the lifting action of the cloth presser foot. The height of the cloth presser foot (11) can be arbitrarily adjusted by arbitrarily adjusting the abutting position of the driven body with respect to the outer peripheral cam by the presser foot motor. In addition, because the cloth presser foot (11) is moved up and down by the presser foot motor without using a solenoid, noise, and loss and damage of components caused by collision can be reduced.

Description

Sewing machine

Technical Field

The present invention relates to a sewing machine having a presser foot lifting mechanism for lifting a cloth presser foot.

Background

The existing sewing machine is provided with a presser foot lifting mechanism, and the presser foot lifting mechanism comprises the following components: a presser bar for holding the cloth presser; a presser foot spring for applying a presser foot pressure downward to the cloth presser foot through the presser foot bar; a lever for applying a lifting motion to the presser bar against the presser spring; and a solenoid for applying a lifting motion to the rod via the plurality of link bodies.

When lowering the cloth presser, the movement of the cloth presser is performed by the spring pressure of the presser spring without driving the solenoid or with the thrust force minimized, and when raising the cloth presser, the solenoid is driven to perform the raising operation (for example, see patent document 1).

Patent document 1: japanese patent laid-open publication No. 2011-092523

However, in the conventional sewing machine, since the solenoid is used as a driving source for raising the cloth presser, it is difficult to arbitrarily control the height of the cloth presser. Further, the cloth presser foot lifting operation by the solenoid has a problem that collision between members is severe, noise is likely to be generated, and wear and damage of the members are likely to be generated.

Further, in the case where the solenoid is used as a driving source for the raising and lowering operation of the cloth presser foot, it is necessary to maintain the movement of the cloth presser foot by continuously supplying power during the raising of the cloth presser foot, and therefore there is a problem that the amount of power consumption becomes large.

Disclosure of Invention

The invention aims to provide a sewing machine capable of performing better lifting action of a cloth presser foot, which has the following characteristics (1) to (7).

(1)

A sewing machine is characterized by comprising:

a rotary peripheral cam;

a driven body abutting against an outer periphery of the outer peripheral cam;

a transmission body which rotates through the driven body and transmits the lifting action to the cloth presser foot;

a presser motor that rotates the outer peripheral cam; and

and a control device for controlling the presser foot motor and controlling the lifting action of the cloth presser foot.

(2)

The sewing machine according to the above (1),

an operation unit for indicating and inputting the height of the cloth presser foot through input operation,

the control device controls the presser foot motor so that the cloth presser foot is at a height corresponding to an input operation amount of the operation unit.

(3)

The sewing machine according to the above (1),

the outer peripheral cam has three neutral sections corresponding to the heights of the cloth presser foot in three steps of a pressing position, a neutral position, and a presser foot lifting position, and having constant outer diameters, and three changing sections provided between the three neutral sections, and the outer diameter of each of the changing sections is changed so as to gradually change from the outer diameter of one of the neutral sections to the outer diameter of the other of the neutral sections on both sides of the outer diameter.

(4)

The sewing machine according to the above (3),

the control device controls the presser foot motor so that the cloth presser foot is at any one of the pressing position, the intermediate position, and the presser foot lifting position in accordance with the input operation of the operation unit.

(5)

The sewing machine according to the above (3),

the control device performs linear control, that is, controls the presser foot motor so that the cloth presser foot has a height corresponding to an input operation amount of the operation unit.

(6)

The sewing machine according to the above (5),

the outer peripheral cam has:

a first neutral zone, a second neutral zone and a third neutral zone, which are the three neutral zones; and

a first variation interval, a second variation interval and a third variation interval of the three variation intervals,

the control device controls the presser foot motor so that any one of a first linear control in a range from the pressing position to the intermediate position and a second linear control in a range from the pressing position to the presser foot lifting position is selectively executed as the linear control, and,

using the first change section between the first neutral section of the outer peripheral cam corresponding to the pressed position and the second neutral section corresponding to the intermediate position in the first linear control,

in the second linear control, the third variation section between the first neutral section of the outer peripheral cam corresponding to the pressing position and the third neutral section corresponding to the presser foot raising position is used.

(7)

The sewing machine according to any one of the above (1) to (6),

the transmission body transmits the descending action to the cloth presser foot through the rotation towards the rotation center side of the peripheral cam,

the sewing machine is provided with an adjusting unit, and the adjusting unit determines the lower limit position of the cloth presser foot by adjusting the approaching limit position of the transmission body to the rotating center side of the peripheral cam.

ADVANTAGEOUS EFFECTS OF INVENTION

The invention provides a sewing machine, which is provided with an outer periphery cam and a presser foot motor, and is provided with a control device for controlling the lifting action of a cloth presser foot by rotating the outer periphery cam through the presser foot motor, therefore, the cloth presser foot can be easily adjusted to any height, and the height of the cloth presser foot can be adjusted according to various requirements related to sewing.

Further, since the vertical movement of the cloth presser is performed by the outer peripheral cam and the presser motor, it is possible to reduce the occurrence of wear and damage of the member while suppressing occurrence of collision and operation noise due to the movement of the member between the two positions as in the case of using the solenoid as a driving source, and thus to realize quietness.

Further, since the cloth presser foot is moved up and down by the outer peripheral cam, in the case where a section having a constant diameter from the rotation center is provided in a part of the cam shape of the outer peripheral cam, even if the power supply to the presser foot motor is reduced or stopped, the driven body can be held at a constant position, and therefore the cloth presser foot can be moved up and down, and the reduction of the power consumption as a problem can be achieved.

Drawings

Fig. 1 is a front view showing the arrangement of the whole structure of a presser foot lifting mechanism in a sewing machine frame.

Fig. 2 is an oblique view of the structure of the presser foot motor periphery.

Fig. 3 is a side view of the peripheral cam and surrounding structure.

Fig. 4 is a block diagram of a control system of the sewing machine.

Fig. 5 is an explanatory diagram showing a relationship between the amount of forward depression of the operating pedal, the amount of rearward depression, and the distribution of the input operation.

Fig. 6 is a flowchart showing operation control of the presser foot raising mechanism.

Fig. 7 is a structural view showing an adjusting unit in which a minute presser foot lift is added to the presser foot lift mechanism.

Description of the reference numerals

10 presser foot lifting mechanism

11 cloth presser foot

14-foot electric motor

15 support bracket

16 sewing machine motor

17 tangent line device

18 operating pedal

20 peripheral cam

21. 22, 23 neutral interval

24. 25, 26 change interval

30 transfer mechanism

31 roller (driven body)

32 initiative connecting rod (transmission body)

40 regulating unit

42 adjusting screw

90 control device

100 Sewing machine frame

Detailed Description

[ outline of embodiments of the invention ]

The following describes a sewing machine according to the present invention with reference to the drawings. Fig. 1 is a side view showing an arrangement of an overall structure of a sewing machine frame 100 provided in a sewing machine and a presser foot lifting mechanism 10 in the sewing machine frame 100.

The sewing machine of the present embodiment is a so-called lockstitch sewing machine, and the presser foot raising mechanism 10 of the sewing machine, which is a characteristic part of the present invention, is mainly described, and the vertical needle moving mechanism, the cloth feeding mechanism, the pot mechanism, the thread adjusting device, the balance mechanism, and the thread cutting device of the general lockstitch sewing machine have the same configurations as those of the known ones, and therefore, the description thereof is omitted.

In the following description, a direction along the longitudinal direction of the base portion 101 of the sewing machine frame 100 shown in fig. 1 in the horizontal direction is referred to as a Y-axis direction, a direction orthogonal to the Y-axis direction in the horizontal direction is referred to as an X-axis direction, and a vertical up-down direction is referred to as a Z-axis direction. As shown in fig. 1, one of the Y-axis directions is "front", the other is "rear", one of the X-axis directions (distal end side of the sheet of fig. 1) is "left", and the other (proximal end side of the sheet of fig. 1) is "right", as necessary.

The sewing machine frame 100 is constituted by: a sewing machine base 101 extending below the sewing machine; a longitudinal body 102 erected from a rear end of the sewing machine base 101; and a sewing machine arm 103 extending forward from an upper end of the vertical body 102.

The front end of the base 101 of the sewing machine is a needle-dropping position, and a needle plate 104 is provided on the upper surface thereof. The needle bar, not shown, is supported in a vertically movable state in the Z-axis direction at the left end of the sewing machine arm 103.

[ schematic Structure of presser foot raising mechanism ]

The presser foot lifting mechanism 10 includes: a cloth presser foot 11; a presser bar 12 for holding the cloth presser 11 at a lower end portion thereof; a rotary peripheral cam 20; a transmission mechanism 30 for transmitting the lifting action from the peripheral cam 20 to the cloth presser foot 11; and a presser motor 14 for rotating the outer peripheral cam 20, wherein the operation control of the presser motor 14 is performed by a control device 90 for controlling the entire structure of the sewing machine.

[ cloth presser foot and presser bar ]

The cloth presser 11 is a so-called boat-shaped presser having a smooth bottom surface and rising upward on the upstream side (front side) in the cloth feeding direction.

The presser bar 12 can be supported in the vicinity of the needle bar in a state of being movable up and down by the sewing machine arm 103 in the Z-axis direction.

A needle bar holding portion 13 is fixedly provided at the upper end of the presser bar 12. The upper end portion of the presser bar 12 is pressed downward by a presser spring, not shown, via the needle bar holding portion 13, thereby securing the presser pressure.

The needle bar holding portion 13 includes a protrusion 131 in the shape of a square column extending rightward, and the protrusion 131 is locked to a hook-shaped lifting plate 35 described later and is applied with an upward lifting force.

[ transfer mechanism ]

The transmission mechanism 30 includes: a roller 31 as a follower abutting on an outer periphery of the outer peripheral cam 20; a driving link 32 as a transmission body that supports the roller 31; a driven link 33 linked with the driving link 32; a connecting rod 34 for connecting the driving link 32 and the driven link 33; and a lifting plate 35 connected to the driven link 33 and lifting the presser bar 12 and the cloth presser 11 via the needle bar holding portion 13.

The roller 31 is supported by the drive link 32 so as to be rotatable about the X axis, and is disposed in contact with an upper portion of the outer periphery of the outer peripheral cam 20.

The drive link 32 is a so-called crank, and is supported in the sewing machine frame 100 so as to be rotatable about the X-axis about a stepped screw. The drive link 32 is provided with two arm portions in two directions, facing radially outward from the shoulder screw. One arm portion extends obliquely rearward and downward and supports the roller 31 at its front end portion, and the other arm portion extends obliquely forward and downward and has one end portion of the connecting rod 34 connected to the other arm portion so as to be rotatable about the X axis.

The driven link 33 is a so-called crank, and is supported by a support shaft, not shown, in the sewing machine frame 100 so as to be rotatable about the X axis. The driven link 33 includes two arms in two directions toward the outside in a radial direction around the support shaft. One arm portion extends forward, and a front end portion thereof is connected to an upper end portion of the lifting plate 35 so as to be rotatable about the X axis, and the other arm portion extends upward, and the other end portion of the connecting rod 34 is connected to the other arm portion so as to be rotatable about the X axis.

As described above, the cloth presser 11 and the presser bar 12 are pressed downward by the presser spring, and the driven link 33 receives a clockwise turning force in fig. 1 via the lifting plate 35. Then, the driving link 32 is given a counterclockwise rotational force via the connecting rod 34, and the roller 31 is pressed against the outer periphery of the outer peripheral cam 20.

[ Presser foot Motor ]

The presser motor 14 is supported in the vertical body portion 102 with its output shaft directed leftward in parallel with the X-axis direction, and a support bracket 15 that supports the outer peripheral cam 20 is assembled to the left side of the presser motor 14.

As shown in fig. 2, the support bracket 15 is configured by a pair of

bracket plates

151 and 152, the

bracket plates

151 and 152 being disposed on both left and right sides of the outer peripheral cam 20, and three support columns 153 connected to each other at intervals so as to insert the outer peripheral cam 20 between the

bracket plates

151 and 152. The right bracket plate 152 is fixed to the presser foot motor 14.

Further, the presser foot motor 14 is rotatably supported by both the

bracket plates

151 and 152, and the load of the motor bearing, not shown, can be reduced.

The presser motor 14, the outer peripheral cam 20, and the support bracket 15 are integrated and unitized with a circuit board, which is described later, on which a drive circuit 142 of the presser motor 14 is formed.

Therefore, the unit can be easily installed on the existing sewing machine without the presser foot motor 14 and the peripheral cam 20, and the sewing machine can be easily modified to control the height of the cloth presser foot 11 by the presser foot motor 14.

[ outer peripheral cam ]

As described above, since the roller 31 supported by the drive link 32 is pressed against the outer peripheral cam 20, the drive link 32 can be rotated by variation in the distance (hereinafter, referred to as displacement) from the rotation center of the outer peripheral cam 20 to the outer periphery. In the case of the structure of the transmission mechanism 30, if the displacement of the outer peripheral cam 20 is small, the cloth presser 11 is lowered, and if the displacement of the outer peripheral cam 20 is large, the cloth presser 11 is raised.

As shown in fig. 3, the outer peripheral cam 20 has a first neutral section 21, a second neutral section 22, a third neutral section 23, and a first change section 24, a second change section 25, and a third change section 26 in one cycle, the first neutral section 21, the second neutral section 22, and the third neutral section 23 are three neutral sections corresponding to the heights of the cloth presser foot 11 in the three stages of the "pressing position", "intermediate position", and "presser foot lifting position", respectively, and the first change section 24, the second change section 25, and the third change section 26 are three change sections provided between the first neutral section 21, the second neutral section 22, and the third neutral section 23.

The "pressing position" is a position where the cloth presser 11 reaches the needle plate 104 and can press the workpiece on the needle plate 104, and is lower than the "intermediate position" and the "presser foot raising position".

The "neutral position" is a height at which the cloth presser 11 is slightly separated upward from the needle plate 104, and is a height at which the presser pressure generated by the cloth presser 11 is released when, for example, a work such as changing the direction of a needle while the needle is inserted into a material to be sewn is performed. The "intermediate position" is a height between the "pressing position" and the "presser foot raising position".

The "presser foot lifting position" is a height at which the cloth presser foot 11 is sufficiently separated upward from the needle plate 104, and is a height at which the cloth presser foot 11 is retracted so as not to interfere with operations such as removal and replacement of a workpiece after completion of sewing. The "presser foot raised position" is a position higher than the "pressing position" and the "intermediate position".

The first neutral zone 21, the second neutral zone 22, and the third neutral zone 23 are formed so that the displacement of the outer periphery thereof is constant. The displacement of the first neutral zone 21 corresponding to the "pressing position" is the smallest, the displacement of the second neutral zone 22 corresponding to the "intermediate position" is the second smallest, and the displacement of the third neutral zone 23 corresponding to the "presser foot raising position" is the largest.

As shown in fig. 3, the second neutral section 22 is located in the counterclockwise direction with respect to the first neutral section 21, and the third neutral section 23 is located in the clockwise direction with respect to the first neutral section 21.

The angular widths of the three

neutral zones

21, 22, 23 are preferably narrower than the angular widths of the three

variation zones

24, 25, 26. However, it is preferable that the roller 31 is maintained in a state of abutting against the outer peripheries of the

neutral sections

21, 22, and 23 at least in a state where the driving of the presser foot motor 14 is stopped.

The three

variation sections

24, 25, 26 are provided between the three

neutral sections

21, 22, 23, respectively.

The outer diameter of the first variation section 24 gradually changes from the outer diameter of the first neutral section 21 to the outer diameter of the second neutral section 22.

The outer diameter of the second variation section 25 gradually changes from the outer diameter of the second neutral section 22 to the outer diameter of the third neutral section 23.

The outer diameter of the third variation section 26 gradually changes from the outer diameter of the third neutral section 23 to the outer diameter of the first neutral section 21.

As shown in fig. 3, the second variation interval 25 is located counterclockwise with respect to the first variation interval 24, and the third variation interval 26 is located clockwise with respect to the first variation interval 24.

[ control System of Sewing machine ]

Fig. 4 is a block diagram showing a control system of the sewing machine provided with the presser foot lifting mechanism 10.

The sewing machine is provided with a control device 90 for controlling the operation of the structure, and the control device 90 is connected with: a presser foot motor 14 serving as a driving source for the lifting operation of the cloth presser foot 11 and an encoder 141 for detecting the output shaft angle thereof; and a sewing machine motor 16 serving as a driving source for sewing operation and an encoder 161 for detecting an output shaft angle thereof.

Further, to the control device 90, there are connected: a thread cutting device 17 for cutting the upper thread and the lower thread when sewing is finished; and a pedal sensor 181 that detects an operation amount from the operation pedal 18, the operation pedal 18 serving as an operation means for an operator to input an operation to the sewing machine.

The control device 90 includes: a CPU 91 for controlling and calculating each part of the presser foot lifting mechanism 10 of the sewing machine; a RAM 92 which becomes a work area of the CPU 91; a ROM 93 that stores programs processed by the CPU 91; and an EEPROM 94 as a storage unit configured to store data used for arithmetic processing and to be capable of rewriting the data.

Fig. 5 is an explanatory diagram showing a relationship between the amount of forward depression of the operating pedal 18 (clockwise rotation angle in fig. 5), the amount of rearward depression (counterclockwise rotation angle in fig. 5), and the distribution of the input operation.

The operating pedal 18 is set to a neutral position as an inclination angle indicated by a solid line in fig. 5, and is returned to the neutral position by applying a spring pressure in a state where the operator is not operating the operating pedal.

The pedal sensor 181 outputs a signal with the neutral position set to 0, the maximum depression amount during forward depression set to Pf, and the maximum depression amount during rearward depression set to Pe. These maximum step amounts coincide with the physical step-in limit positions of the operating pedal 18. Further, in the forward stepping and the backward stepping, the polarities of the detection values output from the pedal sensor 181 are reversed from each other.

The control device 90 drives the sewing machine motor 16 to perform sewing in a range of forward stepping from the stepping amount 0 to Pf of the operating pedal 18. In the range of the stepping amount 0 to Pf, the speed of the sewing machine motor 16 is controlled according to the stepping amount.

Further, when the stepping amount 0 (neutral position) of the operating pedal 18 is detected during sewing, the control device 90 performs control to stop the sewing machine motor 16 at the needle bar lower position (in a state where the sewing needle penetrates the workpiece).

In a range where the pedal sensor 181 is at the neutral position and is depressed forward, the control device 90 controls the cloth presser 11 to be lowered to the pressing position.

On the other hand, the controller 90 performs different operations depending on whether or not the operation pedal 18 is depressed backward, as described later, "in the middle of sewing".

That is, in a state in which the sewing machine is in the middle of sewing, the control device 90 performs the height control of the cloth presser foot 11 corresponding to the stepping amount in a range in which the stepping amount of the back stepping of the operation pedal 18 exceeds 0 and is less than Pn, and performs the thread cutting by the thread cutting device 17 if the stepping amount is greater than or equal to Pn.

In addition, when the sewing machine is not in the middle of sewing, the control device 90 performs the height control of the cloth presser foot 11 corresponding to the stepping amount over the entire range from the stepping amount of the backward stepping of the operating pedal 18 to Pe exceeding 0.

The determination of whether the sewing machine is in the middle of sewing by the control device 90 is performed based on the drive history of the sewing machine motor 16 and the execution history of the thread cutting operation of the thread cutting device 17.

That is, after the main power supply of the sewing machine is turned on, it is determined that the sewing machine is in the "midway non-sewing state" until the sewing machine motor 16 is driven, and if the sewing machine motor 16 is driven and rotated only once, the sewing machine is in the midway sewing state. Then, if the thread cutting is performed, the "midway sewing state" is released to become the "non-midway sewing state", and if the sewing machine motor 16 is driven and rotated only once, the "midway sewing state" is obtained. Then, until the main power supply is turned off, the control device 90 makes the same determination.

[ control of operation of presser foot raising mechanism ]

The operation control of the sewing machine mainly including the presser foot lifting mechanism 10, which is realized by the CPU 91 of the control device 90, will be described in detail based on the flowchart of fig. 6.

First, if the main power source of the sewing machine is turned on, the CPU 91 of the control device 90 determines whether the sewing machine is in a midway sewing state (step S1). As described above, the CPU 91 makes a determination based on the drive history of the sewing machine motor 16 and the execution history of the thread cutting device 17.

Specifically, when the sewing machine motor 16 is not driven at all after the main power supply is turned on or after the thread cutting is performed, it is determined as the "non-sewing halfway state" (step S1: NO), and the CPU 91 allocates the entire range of the depression amount of the back stepping of the operation pedal 18 from 0 to Pe as the height control of the cloth presser foot 11. At this time, the "pressing position" is set at the stepping amount 0 and the "presser foot raising position" is set at the stepping amount Pe, and the positions are distributed so that the height of the cloth presser 11 is increased or decreased in proportion to the stepping amount.

Then, the CPU 91 obtains the height of the cloth presser foot 11 corresponding to the stepping amount Pb detected by the pedal sensor 181 based on the above distribution, and controls the rotation of the presser foot motor 14 so as to be the height (step S19).

Then, the process returns to step S1.

Further, the height adjustment control of the above-described step S19 corresponds to "second linear control". In the second linear control, the height of the cloth presser foot 11 is arbitrarily and linearly controlled in the range from the "pressing position" to the "presser foot lifting position" in accordance with the pedal operation, and therefore, the CPU 91 controls the presser foot motor 14 so that the roller 31 abuts against the third variation section 26 of the outer peripheral cam 20.

On the other hand, in the determination as to whether the sewing machine is in the middle of sewing, when the sewing machine motor 16 is driven after the main power supply is turned on or after the thread cutting is executed, and even if the sewing machine is rotated only once, the sewing machine is determined to be in the middle of sewing (step S1: YES), the CPU 91 allocates the range of the stepping amount 0 to Pn of the back stepping of the operation pedal 18 to the height control of the cloth presser foot 11, and allocates the range exceeding the stepping amount Pn to the execution instruction of the thread cutting by the thread cutting device 17.

Then, the CPU 91 determines whether or not the stepping amount Pb detected by the pedal sensor 181 is within the range of 0 < Pb ≦ Pn based on the above allocation (step S3).

When the stepping amount Pb is in the range of 0 < Pb & ltPn (YES in step S3), it is determined whether or not the current tip end of the sewing needle is at the position under the needle bar below the upper surface of the needle plate based on the detection signal of the encoder 161 of the sewing machine motor 16 (step S5).

In the above determination, when it is determined that the needle bar is at the lower position (YES in step S5), the CPU 91 assigns the "pressing position" at the step amount 0 and the "intermediate position" at the step amount Pn, and assigns the step amounts between these positions so as to increase or decrease the height of the cloth presser 11 in proportion to the step amounts. Then, based on the above distribution, the height of the cloth presser 11 corresponding to the stepping amount Pb detected by the pedal sensor 181 is obtained, and the rotation of the presser motor 14 is controlled so as to be the height (step S7).

Then, the process returns to step S1.

The height adjustment control of step S7 described above corresponds to "first linear control". In the first linear control, the height of the cloth presser 11 is arbitrarily and linearly controlled in the range from the "pressing position" to the "intermediate position" in accordance with the pedal operation, and therefore, the CPU 91 controls the presser motor 14 so that the roller 31 abuts on the first variation section 24 of the outer peripheral cam 20.

Supplementary explanation is given on the significance of the height control of the cloth presser 11 in the step S7.

Step S7 is based on the premise that the sewing machine is in the middle of sewing, the stepping amount Pb of the pedal is in the range of 0 & ltPb & lt & gtPn, and the needle bar is located at the lower position of the needle bar. The sewing machine is in the middle of sewing, which means that there is a sewed object on the needle plate and sewing is currently being performed.

The stepping amount Pb of the pedal backward stepping in the range of 0 < Pb < Pn means that the user of the sewing machine wants to adjust the height of the cloth presser foot 11.

The needle bar is located at the needle bar lower position, which means that the needle bar is stopped in a state where the needle penetrates the material to be sewn.

That is, when the process reaches step S7, the user of the sewing machine intends to stop the sewing in the middle of the sewing and to raise the cloth presser foot 11 upward from the pressing position in the state where the needle is inserted, and there is a high possibility that the user intends to perform an operation such as changing the direction of the object to be sewn.

Therefore, in the above-described case, the control device 90 controls the height adjustment range of the cloth presser 11 so that the linear control can be performed by the operation pedal 18 in the range from the "pressing position" to the "intermediate position", and the height adjustment of the cloth presser 11 can be arbitrarily performed in an appropriate range without excessively raising the cloth presser 11.

On the other hand, when it is determined in the determination of step S5 that the needle bar is not in the needle bar lower position (step S5: NO), the CPU 91 assigns the "pressing position" at the stepping amount 0 and the "presser foot raising position" at the stepping amount Pn, and assigns the stepping amounts between these positions so as to increase or decrease the height of the cloth presser 11 in proportion to the stepping amounts. Then, based on the above distribution, the height of the cloth presser 11 corresponding to the stepping amount Pb detected by the pedal sensor 181 is obtained, and the rotation of the presser motor 14 is controlled so as to be the stepping amount at the height (step S9).

Then, the process returns to step S1.

Further, the height adjustment control of the above-described step S9 corresponds to "second linear control". In the second linear control, the height of the cloth presser foot 11 is arbitrarily and linearly controlled in the range from the "pressing position" to the "presser foot lifting position" in accordance with the pedal operation, and therefore, the CPU 91 controls the presser foot motor 14 so that the roller 31 abuts against the third variation section 26 of the outer peripheral cam 20.

Supplementary explanation is given on the significance of the height control of the cloth presser 11 in the step S9.

Step S9 is based on the premise that the sewing machine is in the middle of sewing, the stepping amount Pb of the pedal is in the range of 0 & ltPb & lt & gtPn, and the needle bar is not located at the lower position of the needle bar.

That is, when the step S9 is reached, the user of the sewing machine wants to stop the sewing in the middle of the sewing and to raise the cloth presser foot 11 upward from the pressing position in a state where the needle is not inserted. In general, when the sewing is stopped in the middle of the sewing, the control device 90 controls the sewing machine motor 16 to stop so that the needle bar is located at the needle bar lower position, but not limited to this, a case where the needle bar is not located at the needle bar lower position means that there is a high possibility that the pulley is manually rotated to raise the needle bar. Various reasons for this are conceivable, but at least: the reason why the needle bar is raised upward from the needle bar lower position is that the needle bar (needle) is retracted due to the needle interfering with the operation.

Therefore, in the above-described case, the control device 90 controls the height adjustment range of the cloth presser 11 so that the linear control can be performed by the operating pedal 18 in the range from the "pressing position" to the "presser foot raising position" and the height adjustment can be arbitrarily performed in the range in which the cloth presser 11 is sufficiently retracted upward.

When it is determined in the determination of step S3 that the pedal depression amount Pb is not in the range of 0 < Pb ≦ Pn (step S3: NO), it is determined whether the pedal depression amount Pb is Pb > Pn (step S11).

When the amount Pb of the pedal is Pb & gt Pn (YES in step S11), it is determined that the instruction input for thread cutting is executed, the presser foot motor 14 is controlled so that the cloth presser foot 11 is lowered to the pressing position (step S13), and thread cutting operation is executed by the thread cutting device 17 (step S15).

Then, the process returns to step S1.

On the other hand, when it is determined in step S11 that the stepping amount Pb of the pedal is not Pb > Pn (step S11: NO), since it indicates that the operation pedal 18 is in the neutral position or in the forward stepping range (0 Pb ≦ Pf), the presser motor 14 is controlled so as to lower the cloth presser 11 to the pressing position (step S17), and the sewing machine motor 16 is stopped or driven at a speed corresponding to the stepping amount.

Then, the process returns to step S1.

[ technical effects of embodiments of the invention ]

The presser foot lifting mechanism 10 includes: the outer peripheral cam 20, the roller 31 as a driven body, the driving link 32 as a transmission body, the presser foot motor 14, and the sewing machine are provided with the control device 90, and the control device 90 controls the presser foot motor 14 to control the lifting operation of the cloth presser foot 11, so that the cloth presser foot 11 can be easily adjusted to an arbitrary height, and the height of the cloth presser foot 11 can be adjusted in accordance with various requirements relating to sewing.

Further, since the cloth presser 11 is moved up and down by the outer peripheral cam 20 and the presser motor 14, it is possible to reduce the occurrence of wear and damage of the member while suppressing occurrence of collision and operation noise due to movement of the member between two positions as in the case of using a solenoid as a driving source, and thus to realize noise reduction.

Further, the sewing machine includes a pedal as an operation means for inputting an instruction to input the height of the cloth presser foot 11 by an input operation, and the control device 90 controls the presser foot motor 14 so that the height of the cloth presser foot 11 corresponds to the input operation amount of the pedal, and therefore, the height of the cloth presser foot 11 can be easily adjusted even during sewing, for example.

Further, the outer peripheral cam 20 has three

neutral sections

21, 22, and 23 corresponding to the heights of the cloth presser 11 at the pressing position, the intermediate position, and the presser foot lifting position, respectively, in one circle, and therefore, even if the power supply to the presser motor 14 is reduced or stopped in the state where the rollers 31 are in contact with the respective

neutral sections

21, 22, and 23, the cloth presser 11 can be maintained at the height of the cloth presser 11 corresponding to each of the neutral sections, and the reduction in the power consumption can be achieved.

Further, since there are three changing

sections

24, 25, and 26, and the outer peripheries thereof gradually or gradually change between the three

neutral sections

21, 22, and 23, the height adjustment between the pressing position, the intermediate position, and the presser foot raising position can be performed smoothly.

Further, the control device 90 controls the presser foot motor 14 so that the cloth presser foot 11 becomes a height corresponding to the input operation amount of the operation pedal 18 by the rotation of the outer peripheral cam 20, and thus the cloth presser foot 11 can be easily adjusted to any height among the pressing position, the intermediate position, and the presser foot lifting position.

The control device 90 controls the presser motor 14 such that the first linear control in the range from the pressing position to the intermediate position and the second linear control in the range from the pressing position to the presser foot raising position are selectively executed in the above-described steps S7, S9, and S19, and that the first changing interval 24 between the first neutral interval 21 corresponding to the pressing position and the second neutral interval 22 corresponding to the intermediate position of the outer peripheral cam 20 is used in the first linear control, and the third changing interval 26 between the first neutral interval 21 corresponding to the pressing position and the third neutral interval 23 corresponding to the presser foot raising position of the outer peripheral cam 20 is used in the second linear control.

Therefore, when the height of the cloth presser 11 is changed gradually or gradually within the adjustment range of the first and second linear controls, it is possible to avoid a state in which any of the neutral sections abuts against the roller 31, and therefore, it is possible to smoothly raise and lower the cloth presser 11 without stopping in the middle.

[ other examples of operation control of the presser foot raising mechanism ]

In the operation control of the presser foot lifting mechanism 10 shown in fig. 6, the linear control is performed for the height of the cloth presser foot 11 in steps S7, S9, and S19, but these may be controlled so that the height is adjusted in stages to be any one of the pressing position, the intermediate position, and the presser foot lifting position.

For example, the presser motor 14 may be controlled so that the cloth presser 11 is at the intermediate position in step S7 of fig. 6, the presser motor 14 may be controlled so that the cloth presser 11 is at the presser foot raised position in step S9, and the presser motor 14 may be controlled so that the cloth presser 11 is at the presser foot raised position in step S19.

Accordingly, the roller 31 can be brought into contact with any one of the three

neutral zones

21, 22, and 23 of the outer peripheral cam 20, and the power supply to the presser foot motor 14 can be reduced or stopped during this period, and therefore, the power consumption of the sewing machine can be reduced.

[ adjusting unit for lifting micro presser foot ]

As shown in fig. 7, the presser foot lifting mechanism 10 may be provided with an adjusting unit 40 for lifting the minute presser foot.

The adjusting means 40 is for determining the lower limit position of the cloth presser foot 11 by adjusting the approach limit position of the driving link 32 as a transmission body toward the rotation center side of the outer peripheral cam 20, and is composed of, for example, a screw hole 41 provided in the sewing machine frame in the Z-axis direction and an adjusting screw 42 screwed into the screw hole 41.

The lower end of the adjustment screw 42 is a contact end that contacts the drive link 32, and the upper end is a head for performing a rotation operation. The head portion may be knurled for manual rotation, or may have a hexagonal outer periphery or a hexagonal hole in an upper end surface for rotation with a tool.

The lower end portion of the adjustment screw 42 abuts against the one arm portion of the drive link 32 that does not hold the roller 31 from above, and by rotating the adjustment screw 42, the drive link 32 is rotated clockwise, and the roller 31 can be moved in a direction away from the outer circumferential cam 20.

The adjusting means 40 can separate the position of the roller 31 closest to the rotation center side of the outer peripheral cam 20 from the rotation center, and can move and adjust the lower limit position of the cloth presser 11 (normally, the pressing position becomes the lower limit position) to be higher than the pressing position in accordance with the amount of separation movement.

For example, in the case of a thick material to be sewn, the lower limit position of the cloth presser foot 11 is slightly shifted upward from the pressing position, for example, to a degree that a slightly narrower gap is formed than the thickness of the cloth, whereby the thick material to be sewn can be favorably conveyed. So-called adjustment of the fine presser foot lift can be performed.

[ others ]

In the sewing machine described above, the operation control is performed such that the vertical movement of the cloth presser 11 is interlocked with the thread cutting device (steps S13 and S14 in fig. 6), but the vertical movement of the cloth presser 11 may be interlocked with other structures of the sewing machine.

For example, in a sewing machine including a thread holder device for holding a sewing start end portion of a top thread at the start of sewing on the lower side of a needle plate, when the above-described presser foot lifting mechanism 10 is provided, the cloth presser foot 11 may be temporarily moved upward at a timing when the thread holder device holds the sewing start end portion of the top thread so that the top thread is not pressed by the cloth presser foot 11, and the pulling operation of the top thread held by the thread holder device may be smoothly performed.

Further, the operation control of releasing the material to be sewn can be performed by moving the cloth presser foot 11 upward by a predetermined number of needles or a predetermined upper axis angle in accordance with the rotation speed or the upper axis angle of the sewing machine by interlocking the presser foot lifting mechanism 10.

Further, in the above-described sewing machine, the pair of

brackets

151 and 152 supported via the outer peripheral cam are provided, and the presser foot motor 14 is fixed by one bracket 152, but a structure may be adopted in which the support bracket plate 151 and the three support columns 153 are omitted by using a motor shaft and a motor bearing having sufficient rigidity, and cantilever support is realized only by the bracket 152.

Claims

1. A sewing machine is characterized by comprising:

a rotary peripheral cam;

a driven body abutting against an outer periphery of the outer peripheral cam;

a presser motor that rotates the outer peripheral cam; and

a control device for controlling the presser foot motor and controlling the lifting action of the cloth presser foot,

the outer peripheral cam has three neutral sections corresponding to the heights of the cloth presser foot in three steps of the pressing position, the middle position and the presser foot lifting position and having constant outer diameters and three variation sections arranged among the three neutral sections,

the outer diameter of each of the variable sections is changed such that the outer diameter of one of the neutral sections is gradually changed from the outer diameter of the other of the neutral sections on both sides of the variable section having different outer diameters.

2. The sewing machine of claim 1,

3. The sewing machine of claim 1,

4. The sewing machine of claim 3,

the outer peripheral cam has:

5. Sewing machine as in any of claims 1 to 4,