JPH08112480A - Balancing mechanism of sewing machine - Google Patents

Abstract

PURPOSE: To provide the balance adjusting mechanism of a sewing machine which can remove surely inertial force to be generated at an upper spindle and prevent the generation of the vibration of the sewing machine. CONSTITUTION: An actuator 29 is fitted to one end portion of the upper spindle 1 of a sewing machine, and at the same time, at this actuator 29, a straight motion spindle which protrudes radially and at whose tip portion a weight 31 is fixed is provided so as to be able to advance and retreat by the action of the actuator 29, and a drive device 34 to output to the actuator 29 a drive signal for driving the actuator 29 according to the rotary angle of the upper spindle 1 is arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balance adjusting mechanism for a sewing machine, and more particularly to a balance adjusting mechanism for removing an inertial force generated by rotation of an upper shaft of a sewing machine.

[0002]

2. Description of the Related Art Generally, in a sewing machine, the rotational movement of the upper shaft of the sewing machine is transmitted to a needle bar mechanism through a balance mechanism to move the balance and the needle bar up and down during sewing. It is known that the vertical movement of the balance and the needle bar at this time causes vibration, wear of the sliding portions of the balance mechanism and the needle bar mechanism increases, and noise is generated. Therefore, a sewing machine has conventionally been provided with a balance adjusting mechanism for reducing the vibration.

FIG. 5 shows such a conventional general sewing machine. An upper shaft 1 having a long cylindrical shape has a cylindrical upper shaft front metal 2 and an upper shaft held by a sewing machine main body. A flywheel 5 is rotatably supported by a middle metal 3 and an upper shaft rear metal 4. At one end of the upper shaft 1, there is provided a flywheel 5 which is rotationally driven from a drive system (not shown) via a transmission means such as a V-belt. It is fixed by the flywheel screw 6. A counterweight 7 is attached to the other end of the upper shaft 1 with a set screw 8, and the counterweight 7 is attached to the upper shaft 1.
A through hole 9 is formed eccentrically with respect to. further,
A feed eccentric cam 10 is arranged between the upper middle metal 3 and the upper rear metal 4 of the upper shaft 1.

A balance 11 is provided near the counterweight 7.
The balance 11 includes a balance crank 13 having a tip end supported by a balance support shaft 12 held by a sewing machine main body, and a link protruding substantially in an L shape with respect to the balance crank 13. Each has a balance 14. A protective plate is provided in the through hole 9 of the counterweight 7, and the link balance 1
4, a needle bar crank 16 is inserted and fixed by a set screw 17 via a tip portion of No. 4 and a needle bearing 15, and the needle bar crank 16 is rotationally driven by the rotating operation of the counterweight 7, and the balance is also 11 is swingably driven up and down.

A needle bar crank rod 19 is attached to the eccentric tip of the needle bar crank 16 via a needle bearing 18 by a crank rod set screw 20, and the lower end of the needle bar crank rod 19 is attached. In addition, a shaft portion 22a protruding laterally of the needle bar holder 22 via a needle bar holder guide roller 21 guided in the vertical direction by a guide (not shown) is rotatable with respect to the lower end portion of the needle bar crank rod 19. Has been inserted into. Further, a needle bar 26 supported by a needle bar upper metal 24 and a needle bar lower metal 25 so as to be capable of reciprocating in the vertical direction is attached to the needle bar holder 22. The lower end portion of the needle bar 26 is attached to the needle bar 26. , The needle 27 is fixed.

In such a conventional sewing machine, the upper shaft 1 is supported by the upper shaft front metal 2, the upper shaft middle metal 3, and the upper shaft rear metal 4 by rotating the flywheel 5 by a drive system (not shown). While being driven, the counterweight 7 is driven to rotate. As a result, the needle bar crank 16 is eccentrically driven to rotate, and the balance 11 is driven to swing up and down.
The rotation of the needle bar crank rod 19 drives the needle bar 26 to reciprocate up and down through the needle bar holder 22.

And, in general, in the above-mentioned sewing machine,
By the rotation operation of the upper shaft 1, the needle bar 26 reciprocates in the vertical direction via the needle bar crank 16 which is eccentrically driven to rotate with respect to the upper shaft 1, and the balance 11 swings in the vertical direction. Since movement is performed, when the upper shaft 1 is rotated, an inertial force is generated on the upper shaft 1.

FIG. 6 shows a reaction force radially applied to the inside of the upper shaft front metal 2 by the inertial force of the upper shaft 1 generated with respect to the rotation angle of the upper shaft 1. While the shaft 1 rotates once, a reaction force of different magnitude is applied to the inside of the upper shaft front metal 2 due to the rotational position of the upper shaft 1, and different loads are applied to the upper shaft front metal 2 in the circumferential direction. I understand that.

The inertial force applied to the upper shaft 1 has a secondary component or more generated by the rotation of the needle bar crank 16 and the swing motion of the balance 11, in addition to the primary component generated by the rotational driving of the upper shaft 1. It is considered that the higher-order components are added to generate. In particular, when the upper shaft 1 is driven at high speed, the inertial force of the higher-order component is greatly affected by the swing of the balance 11.

In the conventional sewing machine, the inertial force generated on the upper shaft 1 is removed by the counterweight 7 attached to the upper shaft 1.
Can remove only the primary component of inertial force,
It has little effect on higher-order components of the second or higher order.

Therefore, conventionally, there is one shown in FIG. 7 as a means for removing such an inertial force. In this, a support shaft 28 is arranged at the end of the upper shaft 1 in parallel with the upper shaft 1, and the counterweight 7 having a substantially fan shape is attached to the support shaft 28.
It is designed so that it can be mounted swingably around.

[0012]

However, in the conventional balance adjusting mechanism, it is possible to reduce the vibration of the upper shaft 1 in the twisting direction, but it is caused by the swinging motion of the balance 11 or the like. Upper axis 1 based on second- and higher-order components
The inertial force of the sewing machine cannot be effectively removed, and the sewing machine itself has a problem of vibration.

The present invention has been made in view of these points, and it is possible to reliably remove the inertial force generated on the upper shaft and prevent the occurrence of vibration of the sewing machine. It is intended to provide.

[0014]

In order to achieve the above object, a balance adjusting mechanism for a sewing machine according to the present invention is a balance adjusting mechanism for a sewing machine for removing inertial force generated by rotation of an upper shaft of a sewing machine. An actuator is attached to one end of the upper shaft, and a linear drive shaft protruding in the radial direction and having a weight attached to the tip of the actuator is arranged so as to be movable back and forth by the operation of the actuator. A drive device for outputting a drive signal for driving the actuator to the actuator according to the above is provided.

Further, preferably, a relay device for relaying a drive signal from the drive device to the actuator is disposed in the middle of the upper shaft.

[0016]

According to the balance adjusting mechanism of the sewing machine according to the present invention,
The driving device outputs a drive signal to the actuator so as to generate an inertial force having an opposite reaction force to the inertial force originally generated on the upper shaft, depending on the rotation angle of the upper shaft, whereby the actuator is When driven, the linear motion shaft is moved back and forth, and the weight is moved in the radial direction. Thereby, the inertial force of the upper shaft can be changed according to the rotation angle of the upper shaft, and originally, the inertial force generated in the upper shaft and the inertial force in the opposite direction generated by the movement of the weight are generated. The resultant force acts on the upper shaft, and the inertial force generated on the upper shaft can be almost canceled.

[0017]

Embodiments of the present invention will be described below with reference to FIGS.

1 to 3 show an embodiment of a balance adjusting mechanism for a sewing machine according to the present invention, in which a cylindrical upper shaft front metal 2, upper shaft middle metal 3 and upper shaft rear of the sewing machine body are shown. At one end of the upper shaft 1 rotatably supported by the metal 4,
A flywheel 5 rotatably driven from a drive system (not shown) via a transmission means such as a V-belt is fixed by a flywheel screw 6. The other end of the upper shaft 1 is provided with the conventional one in the present embodiment. Actuator 2 instead of the counterweight
9 is attached. In addition, this actuator 29
A linear movement shaft 30 protruding in the radial direction is provided so as to be movable back and forth by the operation of the actuator 29, and a weight 31 is fixed to the tip of the linear movement shaft 30.
Further, the actuator 29 is provided with a through hole 32 which is eccentric with respect to the upper shaft 1, and a needle bar crank (not shown) is attached to the through hole 32.

A relay 33 for relaying a drive signal for driving the actuator 29 is disposed in the middle of the upper shaft 1, and the actuator 29 has a relay 33. A drive device 34 for outputting a drive signal for driving the relay device 33 to the repeater 33 is connected. Further, the drive device 34 is connected to a detector 35 that detects the rotational phase angle of the upper shaft 1 and outputs a detection signal to the drive device 34.

Next, the operation of this embodiment will be described.

In this embodiment, by rotating the flywheel 5 by a drive system (not shown), the upper shaft 1 is rotated while being supported by the upper front metal 2, the upper middle metal 3, and the upper rear metal 4. It is driven and the actuator 29 is also rotated together. As a result, the needle bar crank (not shown) is eccentrically driven to rotate, and the balance is driven to swing up and down, so that the needle bar reciprocates up and down by the rotation of the needle bar crank.

At this time, in the present embodiment, the rotation angle of the upper shaft 1 is constantly detected by the detector 35, and the detection signal of the detector 35 is output to the drive unit 34 to drive this drive. As shown in FIG. 4, the device 34 outputs a drive signal to the actuator 29 via the relay 33 so as to generate an inertial force having a reverse reaction force to the inertial force shown in FIG. 6 of the related art. . Then, by driving the actuator 29 based on this drive signal, the linear motion shaft 30 is moved forward and backward, and the weight 31 is moved in the radial direction. Thereby, the inertial force of the upper shaft 1
That the resultant force of the inertial force generated on the upper shaft 1 and the inertial force in the opposite direction generated by the movement of the weight 31 acts on the upper shaft 1. Therefore, the inertial force generated in the upper shaft 1 can be almost cancelled.

Therefore, in this embodiment, the actuator 29 moves the weight 31 in the radial direction via the linear motion shaft 30 so that the inertial force of the upper shaft 1 is changed in accordance with the rotation angle of the upper shaft 1. Since the inertial force generated in the upper shaft 1 can be almost canceled out by changing it, the inertial force of not only the primary component generated in the upper shaft 1 but also the higher-order component can be completely removed, and the vibration of the sewing machine can be prevented. It can be surely prevented.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified as necessary.

[0025]

As described above, in the balance adjusting mechanism for a sewing machine according to the present invention, the inertial force of the upper shaft is adjusted by moving the weight in the radial direction by the actuator via the linear shaft. Since the inertial force generated on the upper shaft can be almost canceled out by changing it according to the rotation angle, it is possible to completely remove not only the primary component generated on the upper shaft but also the higher-order component, and the vibration of the sewing machine. There is an effect such that the occurrence of can be reliably prevented.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a balance adjusting mechanism for a sewing machine according to the present invention.

FIG. 2 is a side view of the actuator portion of FIG.

3 is a front view of the actuator portion of FIG.

FIG. 4 is an explanatory view showing the bearing reaction force with respect to the rotation angle of the upper shaft according to the present invention.

FIG. 5 is an exploded perspective view showing a conventional general sewing machine.

FIG. 6 is an explanatory view showing a bearing reaction force with respect to a rotation angle of a conventional upper shaft.

FIG. 7 is a partial perspective view showing a conventional balance adjusting mechanism.

[Explanation of symbols]

 1 Upper shaft 5 Handwheel 29 Actuator 30 Direct-acting shaft 31 Weight 33 Repeater 34 Drive device 35 Detector

Claims (2)

[Claims] 1. A balance adjusting mechanism for a sewing machine for removing an inertial force generated by rotation of an upper shaft of a sewing machine, wherein an actuator is attached to one end of the upper shaft, and the actuator is provided with a tip protruding in a radial direction. A linear drive shaft to which a weight is fixed is arranged so that it can move back and forth by the operation of the actuator, and a drive device that outputs a drive signal for driving the actuator to the actuator according to the rotation angle of the upper shaft is arranged. A balance adjusting mechanism for the sewing machine characterized by being installed. 2. The balance adjusting mechanism for a sewing machine according to claim 1, wherein a relay device for relaying a drive signal from the drive device to the actuator is provided in a middle portion of the upper shaft.