JPS5930439B2 - Sewing machine pedal drive device - Google Patents

Description

[Detailed description of the invention] The present invention relates to a driving device for a sewing machine pedal.

Clutch motors have been widely used to drive sewing machines, particularly industrial sewing machines, and the operation of the clutch brake is normally controlled on and off by a mechanical lever.

In recent years, with the aim of reducing operating force, simplifying control, and improving accuracy, an electromagnetic clutch motor that can be electrically operated and controlled has been developed by replacing the conventional mechanical clutch brake with an electromagnetic clutch brake.

The construction of an industrial sewing machine equipped with such a motor is shown in FIG.

That is, a clutch motor 3 equipped with a controller 2 is fixed to a sewing machine table 1, and a lever 4 connected to a sewing machine pedal 5 via a connecting rod 6 is attached to a case of the controller 2.

In such a general industrial sewing machine, the operation of the sewing machine pedal 5 and the sewing machine sequence are set in a normal relationship.

That is, the sewing machine pedal 5 is located at the neutral position A, and by stepping down from A to B (forward), the sewing machine changes from low speed to high speed operation.

When the sewing machine pedal 5 is returned to position A, the sewing machine stops with the needle in the lower position (the needle is inserted into the cloth).

In this state, if you step in direction B again, you can continue high-speed sewing, but if you kick it back from position A to position C, the sewing machine needle will move to the upper position (the needle has come out of the fabric) and stop. .

Furthermore, some sewing machines have a sequence in which the thread cutting operation is completed after stopping at the upper position.

A pedal drive device for a sewing machine having such a sequence requires a lever mechanism suitable for the operation of the pedal 5, and a spring mechanism for returning the pedal 5 to the neutral position A via the lever.

FIG. 2 shows an example of a conventional device.

The lever 4 is rotatably mounted around a lever pin 7 mounted on the case 21 of the controller 2.
One end of a tension spring 8 is supported in the middle.

The other end of the tension spring 8 is locked to a pin 9 fixed to the case of the controller 2.

Further, a compression spring 10 is provided at the tip of the lever 4, and this compression spring 10 applies a clockwise rotational force to the lever 4.

As shown in FIG. 3, the compression spring 10 is a rod 1 that is vertically slidable inside a housing 14 having a U-shaped cross section.
1, a compression spring 12 press-fitted into the rod 11 and the housing 14, and a retaining ring 13 for locking the rod 11 to the housing 14.

Further, the tension spring 8 is used to apply a counterclockwise rotational force to the lever 4, and is designed to prevent the tension spring 8 from coming off the flexing pin 9 when the pedal 5 is kicked back as shown in FIG. It has a double structure to make it more durable.

That is, an outer spring 15 whose one end is locked to the lever 4
A hook 18 whose other end is fixed to a screw 17 having a hole 16 in the center, passes through the hole 16 in the outer spring 15, and whose one end is locked to the pin 9, and the tip of the hook. A compression spring 20 is provided between the nut 19 and the screw 17 to which the outer spring 15 is fixed.

In such a conventional device, the lever 4 matches the movement of the sewing machine pedal 5 well, but there are drawbacks such as the complicated structure of the tension spring 8 and the difficulty in adjusting the spring force of the compression spring 10. Therefore, there are drawbacks such as giving a sense of anxiety to the operator operating the sewing machine and damaging the needle due to operational errors.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pedal drive device in which the spring that applies a predetermined displacement force to the pedal is simple and the spring force can be adjusted.

The apparatus of the present invention will be explained below based on an embodiment shown in FIG.

Reference numeral 24 denotes a lever whose one end is rotatably supported via a lever pin 27, and the other end of the lever 24 is connected via a connecting rod 6 to a sewing machine pedal (not shown).

A compression spring 25 is attached to the tip of the lever 4 for applying clockwise rotational force.

As shown in FIG. 6, this compression spring 25 has a rod 30 slidably installed in a housing 29 having a U-shaped cross section, and is compressed between an adjustment nut 31 screwed to this rod 30 and the housing 29. A spring 32 is interposed.

On the other hand, 26 is a tension spring whose one end is locked to the lever 24 and the other end is fixed to the pin 28, and the tension spring 26 applies a counterclockwise rotational force to the lever 24. .

In the present invention configured as described above, the operator can tighten or loosen the adjustment nut 31 so that he or she can depress the pedal with the force that is most convenient for him or her, depending on his or her age, years of experience, etc. The neutral position of the sewing machine pedal and the forward or backward pedaling force can be freely adjusted, and the occurrence of malfunctions can be minimized or prevented.

Further, the tension spring 26 is a single coil spring, and when mounted, is installed in a relationship as shown in FIG. 7 so that it does not come off the pin 28 when the pedal 5 is kicked back.

That is, the spring 26 with its natural length is installed so that it has a length L' when the lever 24 is in the neutral position.

If it is set in this way with the pedal 5 extended by δ=L'-L, δ
If L' is determined so that .delta.1, the tension spring 26 will not come off from the pin 28 even when the pedal 5 is kicked back.

Furthermore, by making the spring force of the tension spring 26 smaller than the spring force of the compression spring 25, the compression spring will not be deflected when set in the neutral position.

As described above, according to the present invention, at least one of the spring mechanisms for returning the lever connected to the pedal to the neutral position is made adjustable, so that the spring force can be set arbitrarily depending on the pedal operator. Each spring mechanism can be greatly simplified compared to the previous model.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the mounting mechanism of a conventional sewing machine, Fig. 2 is a front view of the conventional pedal and drive mechanism, Fig. 3 is a sectional view of the compression spring, and Fig. 4 is the same. 5 is a front view of the device of the present invention, FIG. 6 is a sectional view of the compression spring, and FIG. 7 is an explanatory diagram of the state of the tension spring when mounted. Explanation of symbols, 1... Sewing machine table, 2...
...Controller, 3...Clutch motor, 4...
... Lever, 5 ... Sewing machine pedal.

Claims (1)

[Claims] 1. A clutch motor that drives the sewing machine, a lever pivotally supported on the clutch motor to operate the clutch motor, a connecting rod that is connected to the lever in a hanging manner, and a tiltable lever that is connected to the lower end of the connecting rod. A tension spring is interposed between the lever and the fixed pin to urge the lever to rotate beyond the neutral position from a predetermined direction, and in addition, a tension spring is provided between the lever and the fixed pin, and a compression spring is provided which applies a spring force on the lever in the opposite direction and greater than the spring force of the tension spring, such that both the tension spring and the compression spring hold the lever in a free neutral position; and A sewing machine pedal drive device characterized in that the spring force of a compression spring is configured to be adjustable.