JP2000093677A - Sewing machine presser foot lifting device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prohibit activation of the sewing machine motor when the presser bar is raised by the knee operation lever while the sewing machine is stopped, and to drive the sewing machine motor when the knee operation lever is operated during sewing. Stopping, improving the operability of the knee operation lever, and improving the safety of the sewing machine operation. SOLUTION: In order to set a work cloth while the sewing machine is stopped, an operation is detected when a knee operation lever is operated by a knee to raise a work clamp 21 and when a knee operation lever is slightly operated from a non-operation position. The switch 66 switches to the ON state,
The sewing machine driving is inhibited based on the signal from the switch 66. Further, when the knee operating lever is erroneously operated during sewing and the work clamp 21 rises higher than the thickness of the work cloth, the sewing machine motor is controlled based on signals from the operation detecting switch 66 and the height detector 62. Driving is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for raising and lowering a presser foot of a sewing machine. It relates to a technology that moves up and down.

[0002]

2. Description of the Related Art Conventionally, in a household electronically controlled sewing machine, a needle bar having a sewing needle attached to a lower end thereof and a presser bar having a presser foot attached to a lower end thereof are provided at the head thereof. There is provided a cloth presser elevating device for moving the presser up and down. That is,
In this presser foot lifting device, a presser bar hanger is provided in the middle of the presser bar, and by manually operating a manual operation lever provided close to the presser bar, the presser bar lowers via the presser bar hanger. The presser foot is raised from the position and the work clamp is switched to the raised position and held. In this state, the work cloth to be sewn is set or the sewn work cloth is taken out.

When raising and lowering the work clamp with the manual operation lever, the manual operation lever is always operated by hand, and the operation of raising and lowering the work clamp is troublesome. A household sewing machine has been put to practical use in which a work clamp can be moved up and down via a knee operation lever operated by the knee. For example, as shown in FIG. 20, in addition to the manual operation lever 128, the knee operation lever 14
8, the presser foot lifting device 120 of the home sewing machine for raising and lowering the presser foot 121 will be described.

[0004] On the head 4 of the arm 3, a holding rod 122 is supported by the frame F so as to be vertically movable.
A holding bar holding member 126 is fixed in the middle of
Is elastically urged downward by the presser spring 123 and presses the work cloth through the cloth presser 121 attached to the lower end. A thread loosening operating member 132 is fixed to the presser bar hanger 126, and a thread loosening plate 100 for switching the thread tension mechanism 130 to a tension released state is connected to the thread loosening operating member 132. By manually turning the manual operation lever 128 rotatably provided on the frame F upward by hand,
Presser bar holding 126 by the cam portion of manual operation lever 128
At the same time, the presser bar 122 is raised to the raised position and locked, and at the same time, the thread tension mechanism 130 is switched to the tension released state by the thread release plate 100 via the thread release operating member 132.

On the other hand, on the bed 1 of the sewing machine, a rotating shaft 145 in the front-rear direction is rotatably supported by the frame.
When the two ends 101a and 101b of the connecting member 101 fixed to the rear end of the rotating shaft 145 abut on the frame F, the rotating range of the rotating shaft 145 is regulated. The arm 3 is provided with a swing lever 102, which is swingable by a pivot pin 103. The swing lever 102 is connected at its left end to a thread loosening operating member 132 and at its right end. It is connected to the upper end of the connecting rod 104.

Further, the lower end of the connecting rod 104
The rotating member 105 is connected to one end of the rotating member 105, and the other end of the rotating member 105 abuts on one end 101 b of the connecting member 101 from above.
06, it is urged counterclockwise in front view. A base end of a knee operation lever 148 is detachably attached to a front end of the rotation shaft 145. That is, in this state, the knee operating lever 148 is moved by the spring force of the pressing spring 123 and the tension coil spring 106 so that the connecting member 10
1 at the normal position L1 where the end 101b contacts the frame F.
Is held in.

[0007] By pushing the operating portion 148a of the knee operating lever 148 to the right with the knee, when the knee operating lever 148 rotates to the operating position L2, the pivot shaft 1 is turned.
45 rotates counterclockwise as viewed from the front, and at the same time as the left end of the swing lever 102 rises due to the downward movement of the connecting rod 104 via the connecting member 101 and the rotating member 105,
Since the thread release operating member 132 is raised, the presser bar 122 is raised via the presser bar hanger 126 as in the case of the manual operation lever 128, and the thread tensioner mechanism 130 is switched to the tension released state by the thread release plate 100. Can be

Here, when the knee operation lever 148 is rotated by the knee, the pressing spring 123 and the tension coil spring 1
Since the rotation is performed against the spring force of No. 06, the spring force increases as the amount of rotation operation increases, that is, as the presser bar 122 is raised higher, and the operability is poor.
Japanese Patent Publication No. 55-4434 discloses an electric presser lifting device that drives a presser rod upward by an electric actuator. Further, in Japanese Patent Publication No. 6-40917, in order to eliminate the drawback of the electric presser device, the spring force of a presser spring for urging the presser bar is reduced by an electric actuator, and the height of the presser bar is reduced. An electric presser lifting device in which the position can be arbitrarily changed is described.

[0009]

In the conventional presser lifting device 120 for a household sewing machine shown in FIG. 20, a start switch for driving a sewing machine motor, a reverse stitching switch and the like are provided in consideration of the operability of an operator. Easy to operate head 4
It is provided in. When the manual press lever 128 is operated and the cloth presser 121 is switched to the raised position and held, the height position of the presser bar 122 at this time is detected and the driving of the sewing machine motor is prohibited. When the sewing machine is stopped and the knee operating lever 148 is operated to raise the presser bar 122 and the work cloth is set below the work clamp 121, if the work of handling fine cloths is The presser foot 121 is not raised to the raised position. At this time, the hand may accidentally touch the start switch and the sewing machine motor may be driven, and an accident such as breakage of the sewing needle is likely to occur. There is.

When sewing a thick cloth having a thickness of several millimeters, the knee operating lever 148 is moved to the normal position L1 because the spring force of the pressing spring 123 does not reach the rotating shaft 145. Between the tension coil spring 1 and the operating position L2 corresponding to the presser foot position of the presser foot 121.
When the knee of the operator inadvertently presses the knee operation lever 148 during sewing, the work clamp 121 rises and does not press the work cloth. There is a problem that the eye tension becomes poor, and the yarn tension mechanism is switched to the tension released state by the yarn loosening plate 100, resulting in a poor yarn tension.

In order to keep the knee operating lever 148 at the normal position L1, a separate biasing spring for constantly biasing the rotating shaft 145 clockwise in front view is provided, or the spring force of the tension coil spring 106 is provided. When the force is increased, the spring force of the biasing spring acts on the operator's knee, so that an error such as inadvertently pressing the knee operation lever 148 is unlikely to occur. When the lever 148 is operated, the spring force of a separately provided urging spring acts simultaneously with the pressing spring 123 and the extension coil spring 106, and the knee operation lever 148 is operated.
There is a problem that the operability of the device is deteriorated.

An object of the present invention is to prohibit activation of the sewing machine motor when the presser bar is raised by the knee operating lever while the sewing machine is stopped, and to drive the sewing machine motor when the knee operating lever is operated during sewing. Stopping, improving the operability of the knee operating lever, improving the safety of the sewing machine operation, and the like.

[0013]

According to a first aspect of the present invention, there is provided a sewing machine presser foot lifting device for moving a sewing machine needle up and down by a sewing machine motor, a work presser attached to a lower end of a presser bar, and a work cloth. A cloth presser vertical movement mechanism that switches between a pressing position and a raised position, a thread tension mechanism that applies tension to the upper thread from the thread spool to the eye of the sewing needle, and a tension release mechanism that switches the thread tension mechanism to a tension released state. And a manual operation lever for operating the presser foot vertical movement mechanism by a manual operation, and a second operation member for operating the presser foot vertical movement mechanism by an operation other than the manual operation. A switch means for detecting that the operation member of No. 2 is being operated to the lifting side of the presser foot and outputting an operation detection signal; and a switch means for detecting the detection signal from the switch means when the sewing machine motor is stopped. It is obtained by a drive prohibition control means for prohibiting the movement.

By operating the second operating member to the lifting side of the presser foot, the presser foot is raised by the presser foot vertical movement mechanism. By the way, when the sewing machine motor is stopped, the second
When the operating member is operated upward on the presser foot, the switch means detects the operation of the second operating member and outputs an operation detection signal. As a result, the drive prohibition control means prohibits driving of the sewing machine motor as soon as the detection signal is received from the switch means. That is, when the second operating member is a knee operating lever and the knee operating lever is operated incorrectly with the knee, the operation detection signal output from the switch means surely prohibits the driving of the sewing machine motor.

According to a second aspect of the present invention, there is provided a cloth presser lifting device for a sewing machine, comprising: a height detector for detecting a height position of the presser bar in real time; a height detector and a switch during sewing; The drive of the sewing machine motor is performed on the condition that the switch means is outputting the operation detection signal and the height position of the presser bar is higher than the height at the start of the output of the operation detection signal. And a drive stop control means for stopping.

In this case, the height detecting means has an actuator such as a potentiometer capable of outputting an electric signal, and detects the height position of the presser bar in real time. The drive stop control means receives the detection signals from the height detection means and the switch means during sewing, the switch means is outputting an operation detection signal, and the height position of the presser bar is an output of the operation detection signal. On condition that the height is higher than the height at the start, that is, when the operation amount of the second operating member becomes large and the presser foot rises to a height equal to or higher than the cloth thickness of the work cloth being sewn, Stop driving the sewing machine motor. Other operations are the same as those of the first aspect.

According to a third aspect of the present invention, there is provided a cloth presser lifting and lowering device for a sewing machine, wherein the presser raising rotary member for raising the presser bar by operating the second operating member is provided. An operation control member for a thread loosening member that operates the tension release mechanism in conjunction with the rotation and an operation control member for the switch means are provided. The release mechanism is configured to operate.

In this case, when the second operating member is operated, the presser-lifting rotary member is rotated to raise the presser bar.
The thread release plate operates the tension release mechanism in conjunction with the presser-lifting rotating member at a later stage of the turning operation of the presser-lifting rotating member. Further, the switch means is operated at the initial stage of the rotation of the presser-lifting rotation member. That is, when the knee operation lever, which is the second operation member, is erroneously operated by the knee, the driving of the sewing machine is prohibited before the presser bar is raised, and the safety of the cloth operation is ensured. Since the second operation member is rarely erroneously operated to a large extent until the later stage of the turning operation of the, the application of tension to the upper thread by the thread tension mechanism can be secured, and the thread tension failure can be prevented. These three actions are concentrated on one presser-lifting rotation member, and are more reliably executed. Other effects are the same as those of the second aspect.

According to a fourth aspect of the present invention, there is provided a cloth presser lifting / lowering device for a sewing machine, wherein the presser bar is lifted when the presser-lifting rotary member is rotated from the center of rotation of the presser-lifting rotary member. The horizontal lever length up to the central operating portion is configured to decrease as the rotation angle increases. In this case, when the presser-lifting rotary member is rotated by operating the second operating member to raise the presser bar, the presser-lifting rotary member is rotated from the rotation center of the presser-lifting rotary member. At times, the horizontal lever length up to the central operating portion of the rotary roller for raising the presser bar decreases as the rotation angle increases, that is, as the presser bar is raised. That is, as the presser bar rises, the operating force of the second operating member can be further reduced. Other effects are the same as those of the third aspect.

According to a fifth aspect of the present invention, there is provided a sewing machine presser lifting / lowering device according to any one of the second to fourth aspects, wherein the drive inhibition control means is configured to detect the height detected by the height detection means when the sewing machine motor is stopped. The driving of the sewing machine motor is prohibited even when the position is equal to or more than a predetermined value corresponding to the vicinity of the uppermost position of the presser foot. In this case, when the work clamp is raised to a raised position near the uppermost position, for example, by operating a manual operation lever, the height detecting means determines that the height position detected at this time is equal to or greater than a predetermined value, and Inhibits motor drive. That is, when the presser foot is held at the raised position, both hands of the operator can be used, and even if the start switch is operated by mistake, the start of the sewing machine can be reliably prevented. In addition, the same operation as any one of the second to fourth aspects is achieved.

According to a sixth aspect of the present invention, in the sewing machine lifting and lowering device according to any one of the first to fifth aspects, the sewing machine presser is moved to its raised position via an engaging portion formed on the manual operation lever. It is configured to be locked so that the locked state at the raised position of the work clamp can be released by operating the second operation member. in this case,
When raising the work clamp by operating the manual operation lever,
Even when the presser foot is locked at the raised position via the engaging portion formed on the manual operation lever, the locked state of the manual operation lever at the raised position is reliably released by operating the second operating member largely. it can. In addition, the same operation as any one of the first to fifth aspects is achieved.

According to a seventh aspect of the present invention, there is provided a cloth presser lifting device for a sewing machine, the sewing needle being moved up and down by a sewing machine motor, a cloth presser attached to a lower end of a presser bar, and a pressing position and a raising position for pressing the work presser against a work cloth. A thread presser mechanism for applying tension to the upper thread from the thread spool to the eye of the sewing needle; a tension release mechanism for switching the thread tension mechanism to a tension released state; In a sewing machine presser foot lifting / lowering device including a manual operation lever for operating a presser foot vertical movement mechanism, and a second operation member for operating the presser foot vertical movement mechanism by operating a knee, a hand, or a foot, a second operation is performed. A presser-lifting rotating member whose center of rotation is the center of rotation of the manual operating lever that raises the presser bar by operating the member, and a tension release mechanism that operates in conjunction with the rotation of the presser-lifting rotating member And a thread loosening member The presser lifting rotary member is provided with a thread loosening operation control cam centering on the support shaft of the manual operation lever and a lift difference in the same direction from the rotation center, and the thread releasing member is a rotary operation of the presser lifting rotary member. In a later stage, the tension release mechanism is actuated to release a predetermined amount at the position where the presser foot is raised, and the release amount is maintained when the presser foot is further raised.

When the second operating member is operated, the presser lifting rotating member is rotated to raise the presser bar, and the work clamp is switched to the raised position via the presser vertical movement mechanism. In the later stage of the turning operation of the presser lifting turning member,
The tension release mechanism is operated in conjunction with the presser lifting rotating member. In addition, a predetermined amount is released at the presser foot lifting position by a cam shape by a lift difference in the same direction from the rotation center of the thread loosening operation control cam provided on the presser foot rotating member. Maintain quantity.

That is, when the second operating member, which is the second operating member, is erroneously operated by the knee or the like, the second operating member is operated until the latter half of the turning operation of the presser-lifting turning member. Since the tension is rarely applied to the upper thread by the thread tension mechanism, stitch failure can be prevented, and depending on the cam shape of the thread loosening operation control cam of the presser lifting rotary member,
It is possible to match the thread loosening timing by the second operating member with the thread loosening timing by the manual operation lever.

According to an eighth aspect of the present invention, in the sewing machine lifting device of the seventh aspect, the cloth presser is locked at the raised position via an engaging portion formed on the manual operation lever. The lock state at the raised position of the work clamp can be released by operating the second operation member. In this case, when raising the work clamp by operating the manual operation lever, even if the work clamp is locked at the raised position via the engaging portion formed on the manual operation lever, the second operating member is enlarged. By operating, the locked state of the manual operation lever at the raised position can be reliably released. Other effects are the same as those of the seventh aspect.

According to a ninth aspect of the present invention, in the sewing machine lifting and lowering device according to the seventh aspect of the present invention, the center of the rotary roller for raising the presser bar when the presser-lifting rotary member rotates from the rotation center of the presser-lifting rotary member. The horizontal lever length up to the operating portion is configured to decrease as the rotation angle increases.

When the presser-lifting rotary member is rotated by operating the second operating member to raise the presser bar, the presser-lifting rotary member is rotated from the rotation center of the presser-lifting rotary member. At times, the horizontal lever length up to the central operating portion of the rotary roller for raising the presser bar decreases as the rotation angle increases, that is, as the presser bar is raised. That is, the operating force of the second operating member can be further reduced as the presser bar rises and via the rotating roller.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. This embodiment is an example in which the present invention is applied to an electronically controlled sewing machine capable of sewing various patterns such as a practical pattern and a one-point mark. The electronically controlled sewing machine M is, as shown in FIG.
And a pillar 2 erected from the right end of the bed 1 and an arm 3 extending leftward from the upper end of the pillar 2 so as to face the bed 1. The bed portion 1 includes a feed dog vertical movement mechanism (not shown) for moving the feed dog up and down, a feed tooth back and forth movement mechanism (not shown) for moving the feed dog back and forth, and a thread wheel catcher which accommodates the lower thread bobbin and cooperates with the sewing needle 18. A vessel (for example, a horizontal shuttle) is provided.

A needle bar drive mechanism 10 for vertically moving a needle bar 15 having a sewing needle 18 attached to the lower end thereof, a needle bar 15
There is provided a needle bar swinging mechanism (not shown) for swinging the needle 13 in a direction perpendicular to the cloth feeding direction, a balance driving mechanism (not shown) for moving the balance 13 up and down in synchronization with the vertical movement of the needle bar 15, and the like. ing. The feed dog vertical movement mechanism, the needle bar drive mechanism, and the balance drive mechanism are driven by the sewing machine motor 16, the needle bar swing mechanism is driven by the needle bar swing motor 84, and the feed dog front-rear movement mechanism is It is driven by a drive motor 85 (see FIG. 17). A start / stop switch 7 for instructing start and stop of the sewing work, a reverse stitch switch 8
Are provided.

A large liquid crystal display 5 is provided on the front surface of the arm portion 3, and a transparent electrode is formed on the front surface of the display 5 so as to correspond to each of a plurality of display positions of function names indicating patterns and functions. Touch keys 6 are provided in a matrix. That is, selection of a desired pattern and instruction of a function can be realized by pressing the touch key 6 corresponding to the pattern or function name.

Here, the needle bar drive mechanism 10 will be described with reference to FIG.
In brief, based on the above, a crank member 12 is fixed to the left end of a main shaft 11 disposed on the arm 3, a balance 13 is provided on the crank member 12, and an upper end of a crank lever 14 is The lower end of the crank lever 14 is connected to the interruption portion of the needle bar 15 by pin connection. Thus, when the main shaft 11 is rotationally driven by the sewing machine motor 16 via the belt 17, the crank member 12 is rotated.
At the same time as the needle bar 15 is driven up and down via the crank lever 14, the balance 13 is also driven up and down, and the sewing needle 18 and the thread wheel catcher sew the work cloth pressed by the cloth presser 21 described later. Eyes are formed.

Next, the cloth for driving the cloth presser (presser foot) 21 removably attached to the lower end of the presser bar 22 by the manual operation lever 28 or the knee operation lever 48 (corresponding to the second operation member). The presser lifting device 20 will be described with reference to FIGS. The head 4 has a presser foot 2 at the lower end.
A presser bar 22 to which the control rod 1 is attached is disposed in a vertical direction, and is supported by the sewing machine frame F so as to be vertically movable. By fixing the upper end of the holding spring 23 made of a compression coil spring to the sewing machine frame F and fixing the lower end to the holding rod 22, the holding rod 22 is elastically urged downward.

Next, by operating the manual operation lever 28,
The presser foot vertical movement mechanism 25 that switches the presser foot 21 between the pressing position and the ascending position will be described. A presser bar holder 26 that is long in the left-right direction is fixed to the middle portion of the presser bar 22. On the other hand, at the lower right corner of the head 4, a manually operated lever 28 is pivotally supported by the sewing machine frame F by a pivot shaft 27 oriented in the front-rear direction, and as shown in FIG. The position 28 (L) and the substantially horizontal first operation position 28 (H)
And the second operation position 28 (T), which is higher than this, can be switched.

As shown in FIG. 6, the manual operation lever 28 has a lower inclined end surface 26 on the lower left end of the presser bar holder 26.
a (see FIGS. 7 and 9) and a first operating portion 28b that presses a thread loosening member 32 described below, and a first operating portion 28b that presses an operating plate 67 described later. The two operation parts 28c are formed. That is, as shown in FIG. 9, the manual operation lever 28 is moved to the non-operation position 28 (L).
In this case, the cloth presser 21 is at the pressing position on the upper surface of the needle plate 9, and the presser bar clamp 26 is at the height position 26 (L) indicated by the solid line.

When the manual operation lever 28 is switched to the first operation position 28 (H), the presser bar hanger 26 rises to the height position 26 (H) indicated by the chain line due to the cam shape of the engaging portion 28 a. Further, when the manual operation lever 28 is switched to the second operation position 28 (T), the presser bar hanger 26 further moves up to the height position 26 (T) indicated by the chain line. However, the manual operation lever 28 is switched to the second operation position 28 (T) in a case where a thick cloth is set below the cloth foot 21. Here, when the manual operation lever 28 is switched to the first operation position 28 (H), the engagement portion 28
a engages with the inclined end surface 26a of the presser bar holder 26, the manual operation lever 28 is moved to its first operation position 28 (H).
Locked to.

Next, a thread tension mechanism 3 for applying tension to the upper thread
The tension release mechanism 31 that switches 0 to the tension release state will be described. The thread tension mechanism 30 is a general one configured to apply tension to the upper thread by urging a pair of thread tension discs holding the upper thread with a spring force. As shown in FIGS. 8 and 13, just above the manual operation lever 28, a thread loosening member 32 is pivotally supported on the sewing machine frame F by a pivot pin 33. The lower end of the thread loosening lot 34 is connected to the right end of the thread loosening member 32. The upper end of the thread loosening lot 34 is connected to a movable tension plate (not shown) of the thread tension mechanism 30, as shown in FIG. The thread tension mechanism 30 is switched to the tension release state by being connected and moving the thread loosening lot 34 downward.

That is, the manual operation lever 28 is moved to the non-operation position 2
When the position is switched from 8 (L) to the first operation position 28 (H), as shown in FIG. 10, the thread release member 32 is rotated clockwise in the front view by the first operating portion 28 b of the manual operation lever 28. Therefore, the thread loosening lot 34 is moved downward, and the thread tension mechanism 30 is switched to the tension released state. Next, the presser foot vertical movement mechanism 40 that operates the knee operating lever 48 to switch the presser foot 21 between the pressing position and the ascending position will be described. As shown in FIGS.
8 is provided with a holding member 41 having a substantially U-shape in plan view.
Are pivotally supported by a pivot 27 of a manual operation lever 28.

As shown in FIG. 13, a roller 42 (corresponding to a rotating roller) is rotatably pivoted on a protrusion 41a on the front wall of the press-lifting rotary member 41, and the protrusion on the front wall. A lift cam (which corresponds to the operation control member of the thread loosening member in claim 3 and the thread loosening operation control cam in claim 7) 41d is formed at a stepped portion formed on the upper end surface returning from the 41a toward the center of rotation. ing. Further, as shown in FIG. 15, below the rear wall of the presser
Operation detection switch 6 for detecting operation of knee operation lever 48
An operation protrusion (which corresponds to an operation control member of the switch means) 41b for operating (ON state) the actuator 6 is formed, and a left end of a connection link 51 of a link mechanism 50 described later is formed on the upper protrusion 41c. Are connected.

Here, the lift cam 41d corresponds to a yarn loosening operation control cam based on a difference in lift in the same direction from the center of rotation. That is, when the knee operating lever 48 is operated, the presser lifting rotary member 41 rotates, and when the lift cam 41d engages with a thread loosening pin 35 described later,
When the thread is released above the first raised position, the release amount of the yarn loosening by the yarn loosening member 32 is maintained at the maximum value. On the other hand, as shown in FIGS. 3 and 11, a rotating shaft 45 in the front-rear direction is rotatably supported by the sewing machine frame F on the bed portion 1, and the front end of the rotating shaft 45 is Pair of slots 45a
Is formed in a cylindrical shape having

A base end of a connecting arm 47 urged clockwise in a front view by the spring force of a tension coil spring 46 is fixed to the rear end of the rotating shaft 45. here,
A bolt (not shown) is attached to the rotation shaft 45 to define a rotation range of a knee operation lever 48 described later. The knee operation lever 48 is formed by bending a metal rod, fixing the engagement pin 49 to the connecting portion 48a,
A wide operation section 48b operated by the operator's knee is provided. If necessary, the connecting pin 48a of the knee operating lever 48 is inserted into the front end of the rotating shaft 45 so that the engaging pin 49 is engaged with the slot 45a of the rotating shaft 45,
The knee operation lever 48 is connected to the rotation shaft 45.

Next, a link mechanism 50 for rotating the presser lifting rotary member 41 by operating the knee operating lever 48 to raise and lower the cloth presser 21 will be described with reference to FIGS. The right end of the connection link 51 is connected to an end of a first connection plate 53 rotatably supported by a pivot pin 52 fixed to the sewing machine frame F. On the other hand, the other end of the connecting arm 47 is provided with a link plate 5 bent into a predetermined shape.
4 are connected to each other, and the upper end of the link plate 54 is
Second connecting plate 5 pivotally supported by pivot pins 52
5 is connected to the end.

Here, the first and second connecting plates 53,
Briefly describing 55, the first connecting plate 53 can be finely adjusted with respect to the second connecting plate 55 about the pivot pin 52 as the center of rotation, and the press-up rotation with respect to the position of the knee operation lever 48. The rotation position of the member 41 can be finely adjusted. Here, in FIG. 3, when the knee operation lever 48 is not operated, it is in the non-operation position (P0),
The first operation position (P1) is a position corresponding to a play allowance generated by the link mechanism 50.

That is, in FIG. 3, when the knee operating lever 48 is operated in the counterclockwise direction from the non-operating position (P0), that is, in the upward direction of the presser foot, the connecting arm 47 and the link plate 54 are connected to the first and second connecting members. As shown in FIGS. 14 and 16, the presser-lifting rotating member 41 rotates clockwise as viewed from the front via the plates 53 and 55 and the connecting link 51, so that the roller 42 is rotated.
Lifts the presser bar holder 26 upward from below, and the presser bar 22 and the cloth presser 21 rise at the same time.

As shown in FIGS. 5 and 14, a thread loosening pin 35 which comes into contact with the front wall of the press-up rotating member 41 from above is fixed to the thread loosening member 32 rearward. When the presser-lifting rotating member 41 is rotated clockwise, the thread loosening member 32 is also rotated clockwise through the thread loosening pin 35, and the thread tension mechanism is moved through the thread loosening lot 34 as described above. 30 is switched to a tension release state. Here, as shown in FIG. 14, when the knee operating lever 48 is operated, the lift cam 41d on the front wall of the press-lifting rotary member 41 and the thread loosening at the turning position 41 (p1) of the press-lifting rotary member 41. Since a predetermined clearance dimension is provided between the thread release member 32 and the pin 35, switching to the tension release state by the thread release member 32 is performed by rotating the thread release member 32 When you run.

Next, a height detecting mechanism 60 for detecting the height position of the presser bar 22 will be described with reference to FIGS. 5, 7, 12, and 13.
It will be described based on. On the rear side of the presser bar hanger 26,
A holder plate 61 attached to a plate-shaped auxiliary frame SF fixed to the sewing machine case is provided, and a height detector 62 composed of a potentiometer is provided in front of the holder plate 61.
Is attached, and an operation pin 64 is fixed to a tip of an operation arm 63 fixed to a shaft 62a of the height detector 62,
The tip of the operating pin 64 is in contact with one end of the presser bar holder 26 from above (see FIG. 5). Here, a mounting plate 65 connected to the holder plate 61 so as to be adjustable in position.
In addition, an operation detection switch 66 (corresponding to a switch means) that is operated by the operation protrusion 41b of the presser-lifting rotation member 41.
Is installed.

That is, the shaft 62a rotates via the operating pin 64 and the operating arm 63 in accordance with the height position of the presser bar holder 26 (cloth presser 21). Based on the height detection signal, the height position of the work clamp 21 during sewing of the work clamp 21 can be detected.
On the other hand, as shown in FIGS. 7 and 5, a substantially horizontal and inverted J-shaped operation plate 67 is pivotally supported at one end by a pin 68 on the rear end surface of the presser bar holder 26. .

As a result, when the manual operation lever 28 is operated to switch to the first operation position 28 (H), FIG.
As shown in FIG. 10, the operation plate 67 is rotated clockwise by the second operation portion 28 c of the manual operation lever 28, so that the operation pin 64 is pressed by the operation portion 67 a at the distal end portion of the operation plate 67, , And the height detector 62 outputs a height detection signal of a predetermined value indicating that the work clamp 21 is at the ascending position.

A rearwardly facing engagement pin 69 is fixed to the operation plate 67, and the engagement pin 69 can be engaged with the thread loosening member 32 from the left side. That is, FIG.
As shown in the figure, the manual operation lever 28 is moved to the first operation position 28.
(H), as described above, the presser foot 2
1 is locked at the raised position. At this time, when the knee operating lever 48 is largely operated to the lifting side of the presser foot, when the thread lifting member 32 is rotated clockwise by the The pressing surface 32a of the loosening member 32 (FIG. 13)
Pressing the engagement pin 69 to the left by the
7 will further rotate clockwise.

As a result, the presser-lifting rotating member 41 rotates more, and the presser bar holder 26 is further raised by the roller 42, whereby the engaging portion 28a of the manual operation lever 28 and the presser bar holder 26 are inclined. The engagement with the end face 26a is released,
Further, a gap is generated between the first operating portion 28b of the manual operating lever 28 and the thread loosening member 32, and a gap is also generated between the second operating portion 28c and the operating plate 67. It is no longer supported at any point, falls to the non-operation position 28 (L) by its own weight, and its locked state is released.

Next, a control system of the electronically controlled sewing machine M will be described. As shown in FIG. 17, the control device 75 has an input interface 76, a computer including a CPU 77, a ROM 78 and a RAM 79, an output interface 80, and a bus 81 such as a data bus connecting these. The input interface 76 includes a start / stop switch 7, a touch key 6, an encoder sensor 82 for detecting a plurality of rotational phases of the main shaft of the sewing machine, an operation detection switch 66, and an A / D connected to the height detector 62.
A converter 83 and the like are connected.

The output interface 80 is connected to these motors 16, 84 to 85 and a display controller (LCDC) 86 for the liquid crystal display 5. The ROM 78 stores in advance various control programs related to sewing machine control, including a control program for drive inhibition control and drive stop control specific to the present invention, which will be described later.
The RAM 79 is provided with memories (memory such as flags, pointers, and counters, registers, buffers, and the like) necessary for the above-described various controls.

Next, a description will be given of a drive prohibition control routine executed by the control device C with reference to the flowchart of FIG. However, the reference symbol Si (i = 10, 11,
12) indicate the respective steps. Sewing machine M
After the power is turned on and the initialization process is executed, the drive prohibition control is executed every predetermined minute time while the sewing machine is stopped. That is, when this control is started, first, a height detection signal output from the height detector 62 is read (S1).
0), based on this height detection signal, the actual height position of the presser bar 22 is obtained in real time (S11).

Next, when the height of the presser bar 22 is not at the drive inhibition position corresponding to the raised position (S12: No), and when the operation detection signal from the operation detection switch 66 is OFF (S13). : No), sewing machine motor 16
, The sewing machine drive is permitted (S14),
After terminating this control, the process returns to the main routine. However, when the height of the presser bar 22 is at the drive inhibition position corresponding to the raised position (S12: Yes), or when the operation detection switch 66
(S)
13: Yes), a command is issued to inhibit the sewing machine drive (S
15) Return similarly.

On the other hand, during sewing, the drive stop control shown in FIG. 19 is executed at predetermined small time intervals. That is, when this control is started, the operation detection switch 66
When the operation detection signal in the FF state is received, that is, when the knee operation lever 48 is not operated with the knee (S20:
No), the height detection signal output from the height detector 62 is read (S21), and the actual height position H1 of the presser bar 22 is determined based on the height detection signal (S22). Then, the newly obtained height position H1 is updated as the threshold value J for stopping (S23), this control is ended, and the process returns to the main routine.

On the other hand, when the knee operation lever 48 is operated by the knee and an operation detection signal of the ON state is received from the operation detection switch 66 (S20: Yes), the height output from the height detector 62 is detected. The detection signal is read (S
24), the actual height position H1 of the presser bar 22 is obtained based on the height detection signal (S25). When the newly obtained height position H1 is equal to or less than the stop threshold value J, that is, the knee operation lever 48 is operated, but the height of the work clamp 21 during sewing becomes higher than the cloth thickness. When not,
Without stopping the driving of the sewing machine motor 16 (S2
6: No), and return similarly.

By the way, when the newly obtained height position H1 becomes larger than the stop threshold value J, that is, the knee operating lever 48 is operated during sewing, the height of the work clamp 21 during sewing is reduced. When it is higher than the cloth thickness (S26: Yes),
A command is issued to stop driving the sewing machine motor 16 (S
27), return similarly. Thus, the drive of the sewing machine is stopped when the work cloth is no longer pressed by the work clamp 21, so that occurrence of a stitch defect can be prevented beforehand.

Next, the operation and effect of the sewing machine M configured as described above will be described. First, when the sewing machine is stopped, the manual operation lever 28 is operated to release the non-operation position 28.
By switching from (L) to the horizontal first operation position 28 (H), the manual operation lever 28 is locked at the raised position, and the presser bar hanger 26 is moved to the second position by the cam shape of the engagement portion 28a.
It rises to the height position of 6 (H). At this time, the thread release member 32 is rotated clockwise by the first operating portion 28b of the manual operation lever 28, the thread release lot 34 moves downward, and the thread tension mechanism 30 is switched to the tension released state.

Further, the second operating portion 2 of the manual operation lever 28
At 8c, the operating plate 67 is rotated clockwise, the operating pin 64 is pushed up high by the operating portion 67a of the operating plate 67, and is output from the height detector 62, indicating that the work clamp 21 is at the raised position. The sewing machine drive is prohibited based on the height detection signal having the predetermined value. Then, in this state, the work cloth is set below the work clamp 21 and the manual operation lever 28 is switched to the non-operation position 28 (L). As a result, the work clamp 21 presses the work cloth at a sewing position higher than the needle plate 9 by the work cloth thickness, and the height detector 62 outputs a height position signal corresponding to the work thickness. Is done.

By the way, when the sewing machine is stopped, the knee operating lever 48 is operated to raise the work clamp 21 to set the work cloth, so that the knee operating lever 48 is not operated (P0).
The operation detection switch 66 switches to the ON state when the operation is performed from the first operation position (P1) to the first operation position (P1), and the sewing machine drive is similarly inhibited. Therefore, when the work cloth is set with both hands, the start switch 7 is incorrectly set. The sewing machine motor 16 does not start even if it is operated by the operator, so that safety can be improved.

When the knee operating lever 48 is rotated to the second operating position (P2), the connecting arm 47, the link plate 54, the first and second connecting plates 53 and 55, and the connecting link 51 The presser-lifting rotating member 41 rotates clockwise through the roller, and the roller 42 lifts the presser bar holder 26, so that the presser bar 22 moves the manual operation lever 28 to the first operation position 2.
8 (H), and when the knee operation lever 48 is further pivotally operated to the third operation position (P3), the manual operation lever 28 is moved to the second operation position. It is the same height position as when it was switched to 28 (T).
Here, in FIG. 10, FIG. 14, and FIG. 16, the operating pins 64 corresponding to the positions (P0) to (P3) of the knee operating lever 48 and the turning positions of the presser-lifting rotating member 41 are (p0) to (p0). p3).

By the way, during the sewing, the knee operation lever 48 is
When the erroneous operation to the operation position (P2) or (P3) is performed, the operation detection switch 66 switches to the ON state, and the actual height position H1 of the presser bar 22 becomes higher than the cloth thickness being sewn. In addition, since the driving of the sewing machine motor 16 is stopped, the safety can be improved, and the stitch defect can be reliably prevented. Further, when the holding member 41 is rotated from the center of rotation of the holding member 41,
Since the horizontal lever length up to the roller 42 that raises 2 is configured to decrease as the rotation angle increases, the knee lever 48 is operated to raise the presser bar 22 so that the knee The operation force of the operation lever 48 can be reduced, and the operability of the knee operation lever 48 can be improved.

When the lifting operation is performed by the knee operating lever 48, the thread releasing member 32 is configured to operate the tension release mechanism 31 at a later stage of the rotation operation of the lifting member 41. Until the later stage of the pivoting operation of the pivoting member 41, it is rare that the knee operation lever 48 is erroneously operated to a large extent. The tension application to the upper thread by the thread tension mechanism 30 can be ensured, and the thread tension failure is reduced. It can be reliably prevented. The lifting member 41 and the manual operation lever 28 are configured to be rotatable around the same pivot shaft 27, and the lift cam 41d of the lifting member 41 is
Accordingly, the tension release mechanism 31 is operated, so that the thread loosening member 32 can be used commonly for manual operation and knee operation, which is advantageous in cost.

Further, depending on the cam shape of the lift cam 41d, it is not necessary to adjust the thread loosening timing by the operation levers 28 and 48. Further, the presser-lifting rotating member 41 has a presser-lifting function of the cloth presser 21, a thread loosening function,
Since the operation projection 41b for operating the operation detection switch 66 is integrated, it is not necessary to adjust the timing of each operation, and the assembling work can be simplified. Here, the drive prohibition control means is constituted by the control program of the drive prohibition control and the control device 75, and the drive stop control means is constituted by the control program of the drive stop control and the control device 75.

When the drive of the sewing machine motor 16 is stopped by the drive stop control during sewing, the drive is stopped when the increasing rate of the height position signal output from the height detector 62 is larger than a predetermined value. Alternatively, the thickness of the cloth being sewn may be set, and the drive may be stopped when the height of the cloth presser 21 becomes larger than the cloth thickness during sewing. Further, when the presser bar 22 is raised by operating the knee operating lever 48, the feed dog may be lowered above the needle plate 9 by activating the drop feed mechanism provided in the bed 1. Good.

The present invention should not be construed as being limited to the above-described embodiment, and the configuration of each part of the above-described embodiment may be replaced by existing technology or a person skilled in the art without departing from the technical idea of the present invention. Various changes may be made based on obvious techniques. Further, it is needless to say that the present invention can be applied to a presser lifting device of various sewing machines such as an embroidery sewing machine and a lockstitch sewing machine.

[0066]

According to the first aspect of the present invention, a presser foot of a sewing machine provided with a sewing needle, a presser foot, a presser foot vertical movement mechanism, a thread tension mechanism, a tension release mechanism, a manual operation lever, and a second operating member. In the elevating device, since the switch means and the drive inhibition control means are provided, when the second operation member is erroneously operated with the knee or the foot while the sewing machine is stopped, the driving of the sewing machine motor is reliably inhibited, Since the sewing machine motor does not start even if the start switch is operated by mistake, safety can be improved.

According to the second aspect of the invention, the same effect as that of the first aspect is obtained. However, since the height detecting means and the drive stop control means are provided, the second operating member can be operated by the knee during sewing. If the operation is performed by mistake and the operation amount increases, and the work clamp rises to a height higher than the height corresponding to the thickness of the work cloth being sewn,
The sewing operation can be immediately stopped, and the defective seam can be reliably prevented.

According to the third aspect of the present invention, the same effect as that of the second aspect is obtained, except that a presser-lifting rotation member and an operation control member are provided, and the thread releasing member rotates the presser-lifting rotation member. Since the tension release mechanism is operated in the latter period, the operation control member of the switch means prohibits the sewing machine from being driven before the presser bar rises, thereby ensuring the safety of the cloth operation. Further, since the thread loosening by the operation control member of the thread loosening member is performed in a later stage of the turning operation of the presser-lifting rotating member, the second operation is performed until the latter stage of the turning operation of the presser-lifting rotating member. It is rare that the operating member is erroneously operated to a large extent. The tension application to the upper thread by the thread tension mechanism can be ensured, and the thread tension defect can be reliably prevented.

According to the fourth aspect of the present invention, the same effect as in the third aspect is obtained, but a rotating roller for raising the presser bar when the presser-lifting rotary member rotates from the center of rotation of the presser-lifting rotary member. Since the horizontal lever length up to the center operating portion is configured to decrease with an increase in the rotation angle, the second operation is performed according to the operation of the second operation member to raise the presser bar. The operation force of the member can be further reduced, and the operability of the second operation member can be improved.

According to the fifth aspect of the invention, the same effect as in any one of the second to fourth aspects is obtained, but the drive inhibition control means detects the height by the height detection means when the sewing machine motor is stopped. Even when the height position is equal to or greater than a predetermined value corresponding to the vicinity of the uppermost position of the presser foot, the driving of the sewing machine motor is prohibited.For example, when the manual presser lever is operated to hold the presser foot at the raised position, the operation is performed. Both hands of the user can be used, and even if the start switch is operated by mistake, the start of the sewing machine can be reliably prevented.

According to the sixth aspect of the present invention, the same effect as in any one of the first to fifth aspects is obtained, but the cloth presser is moved to its raised position via an engaging portion formed on the manual operation lever. The lock state at the raised position of the presser foot can be released by operating the second operation member, so that the locked state at the raised position of the manual operation lever is manually operated by the manual operation lever. Can be released by operating the second operating member greatly without releasing it.
Sewing workability can be improved.

According to the seventh aspect of the present invention, a presser foot lifting / lowering device for a sewing machine including a sewing needle, a presser foot, a presser foot vertical movement mechanism, a thread tension mechanism, a tension release mechanism, a manual operation lever, and a second operating member. , A press-lifting rotation member having a rotation center about the rotation center of the manual operation lever and a coaxial center, and a thread releasing member are provided, and the presser-lift rotation member has a support shaft of the manual operation lever as a rotation center. And a thread loosening operation control cam based on a difference in lift in the same direction from the center of rotation. Since it was configured to release and maintain that release amount when the presser foot rises further,
The same effect as the third aspect can be obtained. Further, the support shaft of the lifting member and the manual operation lever can be shared, and the control cams are collectively provided, so that adjustment of the operation timing is not required, and the mounting work can be simplified.

According to the eighth aspect of the present invention, the same effect as that of the seventh aspect is obtained, but the cloth presser is configured to be locked at the raised position via the engaging portion formed on the manual operation lever. Since the locked state at the raised position of the presser foot can be released by operating the second operation member, the same effect as that of claim 6 can be obtained.

According to the ninth aspect of the present invention, the same effect as in the seventh aspect is obtained, but a rotating roller for raising the presser bar when the presser-lifting rotary member rotates from the center of rotation of the presser-lifting rotary member. The length of the horizontal lever up to the center operating portion is reduced as the rotation angle increases.
The same effect as described above can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of an electronically controlled sewing machine according to an embodiment of the present invention.

FIG. 2 is a front view partially showing an internal mechanism related to needle bar driving of the electronically controlled sewing machine.

FIG. 3 is a view corresponding to FIG. 2 relating to a presser bar of the electronically controlled sewing machine.

FIG. 4 is a side view of the presser foot lifting device.

FIG. 5 is a plan view of the presser foot lifting device.

FIG. 6 is an enlarged front view of a manual operation lever.

FIG. 7 is a rear view of the presser bar holding the operation plate.

FIG. 8 is a partially enlarged front view of an arm portion of the electronically controlled sewing machine.

FIG. 9 is a partially enlarged front view of a head portion of the arm portion.

FIG. 10 is an enlarged front view of a main part including a presser bar and a presser bar hug.

FIG. 11 is an enlarged side view of a knee operation lever and a rotation shaft.

FIG. 12 is a partially enlarged rear view of a head of an arm.

FIG. 13 is an enlarged front view of a main part including a presser bar and a presser bar hug.

FIG. 14 is a diagram corresponding to FIG. 13 for explaining the lifting / lowering operation of the presser bar and the presser bar hug.

FIG. 15 is a vertical sectional front view taken along the line OO in FIG. 5;

FIG. 16 is a view corresponding to FIG. 15 for explaining the operation of the presser-lifting rotating member.

FIG. 17 is a block diagram of a control system of the electronically controlled sewing machine.

FIG. 18 is a flowchart of drive inhibition control.

FIG. 19 is a flowchart of drive stop control.

FIG. 20 is a schematic perspective view of a presser foot lifting mechanism according to the related art.

[Explanation of symbols]

 M Electronically controlled sewing machine 16 Sewing machine motor 18 Sewing needle 21 Fabric presser 25 Fabric presser vertical movement mechanism 28 Manual operation lever 28a Engaging unit 30 Thread tension mechanism 31 Tension release mechanism 32 Thread release member 40 Fabric presser vertical movement mechanism 41 Member 42 Roller 48 Knee operation lever 62 Height detector 66 Operation detection switch

Claims (9)

[Claims] 1. A sewing needle moved up and down by a sewing machine motor, a cloth presser attached to a lower end of a presser bar, a cloth presser vertical movement mechanism for switching the cloth presser between a pressing position for pressing a work cloth and an ascending position. A thread tension mechanism that applies tension to the upper thread from the thread spool to the eye of the sewing needle, a tension release mechanism that switches the thread tension mechanism to the tension released state, and a manual operation lever that operates the cloth presser vertical movement mechanism by manual operation And a second operating member for operating the presser foot vertical movement mechanism by an operation other than a manual operation, wherein the second operating member is operated to the presser foot lifting side. And a drive prohibition control unit that prohibits driving of the sewing machine motor when a detection signal is received from the switch unit in a stopped state of the sewing machine motor. A cloth presser lifting device for a sewing machine. 2. A height detecting means for detecting a height position of the presser bar in real time, a detection signal from the height detecting means and a switch means during sewing, and the switch means outputs an operation detection signal. Drive stop control means for stopping driving of the sewing machine motor on condition that the height position of the presser bar is higher than the height at the start of output of the operation detection signal. The sewing machine presser lifting device according to claim 1. 3. An operation of a press-up rotation member for raising the presser bar by operating the second operation member, and an operation of a thread releasing member for operating a tension release mechanism in conjunction with the rotation of the press-up rotation member. 3. The apparatus according to claim 2, further comprising a control member and an operation control member for a switch means, wherein the thread release member is configured to operate the tension release mechanism at a later stage of the rotation operation of the presser lifting rotation member. 3. The lifting device for the presser foot of the sewing machine according to 1. 4. The horizontal lever length from the center of rotation of the presser-lifting rotating member to the center operating portion of the rotating roller that raises the presser bar when the presser-lifting rotary member rotates, increases the rotation angle. 4. The apparatus for lifting and lowering a presser foot of a sewing machine according to claim 3, wherein the apparatus is configured to decrease the number of the pressers. 5. The sewing machine according to claim 1, wherein the drive prohibition control unit controls the sewing machine motor to stop when the height position detected by the height detection unit is equal to or greater than a predetermined value corresponding to the vicinity of the uppermost position of the work clamp. The sewing machine presser lifting device according to any one of claims 2 to 4, wherein driving is prohibited. 6. A cloth presser is locked at its raised position via an engagement portion formed on the manual operation lever, and the locked state of the cloth presser at the raised position is controlled by operation of a second operating member. The sewing machine presser lifting device according to any one of claims 1 to 5, wherein the lifting device is configured to be releasable. 7. A sewing needle moved up and down by a sewing machine motor, a cloth presser attached to a lower end of a presser bar, a cloth presser vertical movement mechanism for switching the cloth presser between a pressing position for pressing a work cloth and an ascending position. A thread tension mechanism that applies tension to the upper thread from the thread spool to the eye of the sewing needle, a tension release mechanism that switches the thread tension mechanism to the tension released state, and a manual operation lever that operates the cloth presser vertical movement mechanism by manual operation And a second operating member for operating the presser foot vertical movement mechanism by operating a knee, a hand, a foot, or the like, wherein the presser bar is raised by operating the second operating member. A presser-lifting rotating member having a center of rotation about the center of rotation of the manual operation lever and a coaxial center; and a thread-releasing member that operates a tension release mechanism in conjunction with the rotation of the presser-lifting rotating member. The lifting member is A thread loosening operation control cam having a pivot about the support shaft of the moving operation lever and a lift in the same direction from the center of rotation is provided, and the thread loosening member releases tension in a later stage of the rotating operation of the presser lifting rotating member. A presser foot lifting device for a sewing machine, wherein the mechanism is operated to release a predetermined amount at a presser foot raising position, and to maintain the release amount when the presser foot is raised further. 8. A structure in which the presser foot is locked at its raised position via an engagement portion formed on the manual operation lever, and the locked state of the presser foot at the raised position is operated by operating a second operating member. The sewing machine presser lifting device according to claim 7, wherein the lifting device is configured to be releasable. 9. The horizontal lever length from the rotation center of the presser-lifting rotating member to the center operating portion of the rotating roller that raises the presser bar when the presser-lifting rotating member rotates, increases the rotation angle. 8. The apparatus for lifting and lowering the presser foot of the sewing machine according to claim 7, wherein the apparatus is configured to decrease the number of the pressers.