JPH08252384A - Safety device for sewing machine - Google Patents

Abstract

PURPOSE: To prevent the damage of the electric circuit of a sewing machine motor by keeping the current feed to the motor in the stopped state when a presser bar guide bracket is situated in an engaging part by rotating a presser bar after raising it. CONSTITUTION: When a presser bar lifter lever 5 is rotated, the presser bar lifter surface 5 of the presser bar lifter lever 5 is engaged with the operating plate lower surface 6a of a presser bar lifter operating plate 6, the operating plate upper surface 6b of the presser bar lifter operating plate 6 slides the engaging part of a presser bar guide bracket 4 fixed to a presser bar 2 between locking parts arranged opposite to the locking parts 1a, 1a of a sewing machine frame 1C, and also rises against a compression spring 4 to raise the presser bar 2. Thus, the step screw 6c of the presser bar lifter operating plate 6 pushes the upper end of an elliptic hole 10b upward to raise an actuator operating plate 10. Since an actuator operating bar 10a is thus raised, the load added to the actuator 9a of a switch part 9 is eliminated, and the actuator 9a is laid in the released state, where the current feed to the motor is stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety device for a presser foot lifting mechanism of a sewing machine.

[0002]

2. Description of the Related Art A conventional safety device for a presser foot lifting mechanism of a sewing machine will be described with reference to FIG. 1A, 1B, 1C and 1D are sewing machine frames that are integral with each other, and the frame 1C includes a locking portion 1a and an engaging portion 1b. Reference numeral 2 denotes a presser bar, which has a presser foot (not shown) at its lower end and is vertically and rotatably inserted through the upper and lower parts of the sewing machine frames 1A and 1B, respectively.

Reference numeral 3 is a presser bar hanger, which has a base end fixed to the presser bar and has a step portion 3a and an engaging portion 3c at the other end. Here, the engaging portion 3c is provided so as to be vertically slidable on an engaging portion (not shown) having one side surface and the other side surface facing the engaging portion 1a. Further, the presser bar holder 3 has a stopper portion 3b which engages with a stopper portion of a needle bar (not shown) to prevent the needle bar from moving up and down.

Reference numeral 4 denotes a compression spring as a pressing means, which is provided around the presser bar 2 and holds the sewing machine frame 1A and the presser bar.
It is placed between 3 and pushes the presser bar hanger 3 downward.
Reference numeral 8 denotes a rotary arm that is a part of the lifting and lowering means for holding the holding bar, which has a long hole into which the holding bar 2 is loosely fitted and whose right end is rotatably supported by a shaft 7 fixed to the sewing machine frame 1D. .

Reference numeral 6 denotes a presser working plate which is a part of the lifting and lowering means for holding the presser bar, which is fixed to the rotating arm 8 and has the lower surface of the working plate at the left end.
6a and operating plate upper surface 6b are provided, and a step screw is provided
6c is provided. Reference numeral 5 denotes a presser foot lifting lever which is a part of the lifting and lowering means for holding the presser bar, which is rotatably mounted around a fixed shaft 5a and is a presser lowering surface 5b which is a cam surface having a different distance from the fixed shaft 5a. And a presser foot lifting surface 5c.

Reference numeral 9 denotes a switch section, which is a sewing machine frame 1A.
The actuator operation hole 9b is formed in a long hole on the side surface that is fixed to the
A microswitch 9c having a 9a above is provided. Explaining the operation of the switch section 9, the actuator 9a is always urged upward, and in the released state, it acts so as to stop the current to the main shaft power motor of the sewing machine (not shown). When it is pressed downward and becomes closed, it acts to supply current to the motor.

Reference numeral 10 denotes an actuator actuating plate, which has an actuator operating rod 10a which extends through the actuator operating hole 9b of the switch section 9 and extends above the actuator 9a, and which has a stepped screw 6c of the presser working plate 6 downward. It has an elongated hole 10b which is loosely fitted in. Actuator operating plate
The reference numeral 10 has a bent first arm portion 10e in the vicinity of the middle thereof and is constantly urged downward by a spring (not shown) provided in the first arm portion 10e.

With the above configuration, the operation is as follows. When the presser foot lowering surface 5b of the presser foot lifting lever 5 and the operating plate lower surface 6a of the presser foot lifting operating plate 6 are engaged with each other, the presser foot is in a lowered state. Here, when the presser foot lifting lever 5 is rotated, the presser foot lifting surface 5c of the presser foot lifting lever 5 comes into engagement with the operation plate lower surface 6a of the presser foot lifting operation plate 6. That is, the rotating arm 8
The presser foot actuating plate 6 fixed to the shaft 7 is rotated about the shaft 7 by the cam action by the difference between the distance between the lever shaft 5a and the presser foot lowering surface 5b and the distance between the lever shaft 5a and the presser foot lifting surface 5c. It will be.

For this reason, the operating plate upper surface 6b of the presser-lifting operating plate 6 has an engaging portion 3c of a presser bar holder 3 fixed to the presser bar 2.
Is slid between the locking portions 1a of the sewing machine frame 1C and a locking portion (not shown) arranged to face the sewing machine frame 1a, and is raised against the compression spring 4, so that the presser bar 2 is raised. Therefore, the stepping screw 6c of the work clamp lifting plate 6 is
Pushes the upper end of slot 10b upward,
To rise. As a result, the actuator operating rod 10a
Moves up in accordance with the actuator operation hole 9b, the load on the actuator 9a of the switch unit 9 is removed, the actuator 9a is released, and the current supply to the motor is stopped.

After that, when the presser bar 2 is rotated, the step surface 3a of the presser bar holder 3 fixedly attached to the presser bar 2 causes the presser bar lifting plate.
Go over 6 and move to the engaging portion 1b. Therefore, when the presser bar holder 3 is in the engaging portion 1b, the presser bar 2 does not descend even if the presser bar lifting lever 5 is rotated. Further, when the presser bar hanger 3 is in the engaging portion 1b, the presser bar hug 3
The stopper portion 3b engages with the stopper portion of the needle bar (not shown) to suppress the movement of the needle bar.

However, when the presser bar 2 is lifted and the presser bar holder 3 is moved to the engaging portion 1b, if the presser bar lifting lever 5 is rotated by an erroneous operation, the presser bar is fixed to the rotating arm 8. The lowering actuating plate 6 pivotally descends about the shaft 7, and the actuator actuating plate 10 descends in conjunction therewith, whereby the actuator operating rod 10a pushes the actuator 9a downward to close the sewing machine motor. Supply current to the. Even if the sewing machine is operated in this state, the needle bar stopper engages with the stopper 3b of the presser bar holder 3 to prevent the needle bar from moving, so it is safe, but it flows to the motor. The current may become overcurrent and damage the electric circuit of the motor.

[0012]

SUMMARY OF THE INVENTION According to the present invention, when the presser bar 2 is raised and then rotated, the current supply to the sewing machine motor is kept stopped when the presser bar holder 3 is in the engaging portion 1b. The purpose is to prevent damage to the electric circuit of the motor.

[0013]

A presser bar having a presser foot at its lower end, which is vertically movably and pivotally inserted into a sewing machine frame, pressing means for pressing the presser bar downward, and a presser foot fixed to the presser bar. A rod holding member, a locking portion which engages with the holding rod holding member and prevents rotation of the holding rod when the holding rod is in the lowered position, and a holding portion which engages with the holding rod holding member and is turned in the raised position. , An engaging portion for holding the presser bar in a raised state when in the ascending rotation position, a presser bar lifting / lowering means for lifting / lowering the presser bar hanger, and an actuator operation plate which moves up and down in conjunction with the presser bar hanger lifting / lowering means In a safety device of a sewing machine including a switch section having an actuator for switching between supplying and stopping a current to the sewing machine motor via the actuator operating plate, the safety device is arranged between the presser bar hanger and the actuator operating plate. Comprising an actuation plate falling prevention means for holding the actuator operation plate in the raised position in conjunction with be locked in ascending rotation position.

[0014]

Operation: The holding bar holding body which is fixed to the holding bar and is pressed downward by the pressing means is raised by operating the holding bar lifting / lowering means. When the actuator operating plate rises in conjunction with the rise of the presser bar holding lifting means, the actuator is switched and the current supply to the sewing machine motor is stopped. After that, when the presser bar hanger is rotated and moved to the engaging portion, the operating plate lowering prevention means maintains the state in which the current supply to the motor is stopped.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 and 2, the same reference numerals as those in FIG. 4 are the same as those in the conventional example, and therefore the description thereof will be omitted. Only the components added by the present invention will be described below. Reference numeral 11 denotes an actuating plate lowering preventing means, which is provided with a second arm 11a integrally formed in the middle of the actuator operating plate and a protrusion 11b below the tip of the second arm 11a.

The protrusion amount of the protrusion 11b will be described with reference to FIG. 3. The protrusion amount of the protrusion 11b is the amount of protrusion of the second arm 11a when the presser bar lifting lever 5 is rotated and the presser bar holder 3 is raised. And the height f of the second arm when the presser bar hanger 3 is rotated to the engaging part 1b and the protrusion 11b of the second arm 11a rides on the presser bar hanger 3 is Presser bar hug 3 to sewing machine frame 1C
It should be larger than the gap g up to the engaging portion 1b.

With the above construction, it operates as follows. Figure
In 1, the presser foot lowering surface 5b of the presser foot lifting lever 5 and the operating plate lower surface 6a of the presser foot lifting operating plate 6 are engaged with each other, and the presser foot is in a lowered state. Here, when the presser foot lifting lever 5 is rotated, the presser foot lifting surface 5c of the presser foot lifting lever 5 comes into engagement with the operation plate lower surface 6a of the presser foot lifting operation plate 6. In other words, the presser foot lifting plate 6 fixed to the rotating arm 8 is centered on the shaft 7 by the cam action by the difference between the distance between the lever shaft 5a and the presser foot lowering surface 5b and the distance between the lever shaft 5a and the presser foot lifting surface 5c. It will be rotated up.

For this purpose, the operating plate upper surface 6b of the presser foot operating plate 6 is engaged with the engaging portion 3c of the presser bar holder 3 fixed to the presser bar 2.
Is slid between the locking portions 1a of the sewing machine frame 1C and a locking portion (not shown) arranged to face the sewing machine frame 1a, and is raised against the compression spring 4, so that the presser bar 2 is raised. Therefore, the stepping screw 6c of the work clamp lifting plate 6 is
Pushes the upper end of slot 10b upward,
To rise. As a result, the actuator operating rod 10a
Moves up in accordance with the actuator operation hole 9b, the load on the actuator 9a of the switch unit 9 is removed, the actuator 9a is released, and the current supply to the motor is stopped.

Thereafter, as shown in FIG. 2, when the presser bar 2 is rotated, the step surface of the presser bar holder 3 fixed to the presser bar 2 is held.
3a moves over the presser foot lifting plate 6 and moves to the engaging part 1b, and at the same time, the upper surface of the presser bar hanger 3 has the protrusion 11b of the second arm 11a.
To hold the actuator operating plate 10 in a raised state. Therefore, when the presser bar hanger 3 is in the engaging portion 1b, the presser foot lifting lever 5 is rotated and the presser foot lowering operation plate 6 fixed to the rotating arm 8 is rotated and lowered about the shaft 7. Actuator 9a
Has the effect that it is held in the released state and no current flows through the sewing machine motor.

As another embodiment, instead of providing a protrusion on the second arm 11a of the actuator actuating plate 10, a protrusion protruding above the presser bar holder 3 is provided so that the presser bar holder is in the raised position. The second arm may be mounted on the upper surface of the protrusion by rotating the arm.

[0021]

The above-mentioned structure has the following effects. Even when the presser bar hanger raising / lowering means is operated by mistake in the state where the presser bar hanger is in the engaging portion, current is not supplied to the sewing machine motor, and the current supply stopped state can be maintained. Will not be damaged.

[Brief description of drawings]

FIG. 1 is a perspective view of a presser bar according to a first embodiment in a state in which the presser bar is lowered.

FIG. 2 is a perspective view when the presser bar of the first embodiment is lifted and the presser bar hanger is rotated to the engaging portion.

FIG. 3 is a front view of a presser bar hanger and a second arm part in a state where the presser bar hanger lifting means is raised, and a presser bar hanger and a second arm part when the presser bar is rotated.

FIG. 4 is a perspective view of a conventional example.

[Explanation of symbols]

 2 Presser bar 3 Presser bar hug 4 Compression spring 5 Presser lifter lever 9 Switch section 10 Actuator operating plate

Claims (1)

[Claims] 1. A presser bar having a presser foot at its lower end, which is vertically movably and pivotally inserted into a sewing machine frame, pressing means for pressing the presser bar downward, and a presser bar hanger fixed to the presser bar. An engaging portion that engages with the presser bar hanger and prevents rotation of the presser bar when the presser bar is in the lowered position; and a locking portion that engages the presser bar hanger and is rotated in the raised position. An engaging portion that holds the presser bar in a raised state when in the ascending rotation position, a presser bar holding lifting means that moves the presser bar holding up and down, and an actuator that moves up and down in conjunction with the presser bar holding lifting means. A safety device for a sewing machine, comprising: an operating plate; and a switch unit having an actuator for switching between supplying and stopping a current to a sewing machine motor via the actuator operating plate, wherein the presser bar hanger and the actuator operating plate are provided. It is disposed between,
A safety device for a sewing machine, comprising: a working plate lowering prevention means for holding the actuator operating plate in a raised position in association with the presser bar being locked in the raised rotation position.