JPS6112946Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an upper feed device of a sewing machine in which an upper feed dog performs four cloth feeding movements, and particularly relates to an improvement for smoothing the drive thereof.

Conventionally, this type of top feed swinging device has a top feed arm whose base end is rotatable around an axis that intersects with the cloth feed direction, and which swings along the cloth feed direction in conjunction with the main shaft of the sewing machine. The upper feed dog is fixed, and a roller that receives downward elastic force from a coiled spring is pressed against the upper surface of the intermediate portion, and the lower surface of the tip side of this roller is connected to a swing mechanism that moves up and down in conjunction with the main shaft of the sewing machine. This allows the upper feed arm to swing in the vertical direction. However, in such conventional devices, when the vertical swing mechanism is operated, the intermediate roller moves up and down while expanding and contracting the spring, so the force of the spring is always involved in the swing motion, causing the sewing machine to drive at high speed. The spring cannot follow the movement of the material, resulting in insufficient pressing force, and the upper feed dog does not feed enough fabric, resulting in unsightly seams and a significant deterioration in product quality.
When the upper feed dog is lifted by a thick part of the fabric such as a step, the upper feed arm is separated upward from the connecting part with the intermediate swing mechanism, and the swing is not transmitted to the upper feed dog, resulting in insufficient feed. Moreover, when the upper feed arm passes through the thick part of the fabric, the roller collides with the upper feed arm due to the elastic force of the spring, resulting in increased vibration and noise, resulting in defects that can lead to wear and breakage of parts.

This invention aims to eliminate the drawbacks of the above-mentioned conventional ones.

An embodiment of this invention will be explained with reference to the drawings. At the rear of the sewing machine, the middle part of a support shaft (not shown) having a horizontal axis perpendicular to the cloth feeding direction (Fig. ), and on one end of the support shaft, an acting body 1 having a pin 1a parallel to the axis A is fixed, and on the other end, a holding body 2 is fixed, and a pin 1 perpendicular to the upper end of the holding body 2 is fixed. The presser arm 3 is supported rotatably around an axis. At the tip of the presser arm 3, there is an upper feed dog 23, which will be described later.
A presser foot 4 having two rows of slots 4a into which tooth portions 23a of The presser foot 3 is movably supported and normally receives an elastic force that presses the presser foot 4 against a throat plate (not shown).

A working arm 5 and a connecting arm 6 are mounted on the bearing that supports the support shaft.
and rotatably supported.

The working arm 5 is formed with a long hole 8 in the shape of an arc centered on the axis A of the support shaft at the base end, and the pin 1a of the working body 1 is inserted into the working arm 5.
loosely fit into the long hole 8. The working arm 5 has a protrusion 9 protruding from the upper part of the proximal end facing above the connecting arm 6, and one side edge of the protrusion 9 is bent upward to form a screw hole 10a substantially along the cloth feeding direction. It is referred to as a connecting portion 10.

An operation lever 12 whose base end is fixed to a support shaft 11 rotatably supported on the machine frame along the cloth feeding direction has its tip connected to an operation body (not shown) such as a petal, and its intermediate portion connected via a connecting rod 13. The screw 14 is connected to the tip of the operating arm 5 and is screwed into the machine frame so that the tip of the screw 14 can be engaged with the upper edge of the operating lever so as to define the initial position of the operating lever 12. The operating lever 12 is rotated by the elastic force of the spring 15 so as to engage with the tip of the screw 14.

The connecting arm 6 projects upward and has a stepped screw 19 with a connecting portion 17 facing the connecting portion 10 of the working arm 5.
An operating portion 18 is provided, which is connected to the main body 1 and is bent in a substantially Z-shape and protrudes toward the front in the cloth feeding direction.

The upper feed arm 21 is a horizontal swing arm 2 that swings about an axis that intersects with the cloth feed direction in conjunction with the main shaft of the sewing machine.
2. The rear end in the cloth feeding direction is rotatably connected to the lower end, and the upper feed dog 23 is fixed to the tip.
a is placed so as to face the slot 4a of the presser foot 4. A guide cam 21a having a cam surface is formed on one side end surface of the intermediate portion of the upper feed arm 21 so as to be able to engage with the upper end of the operating portion 18 of the connecting arm 6. This guide cam 21a prevents the upper feed dog 23 from rising due to the rotation of the connecting arm 6, which will be described later, in all the swinging positions of the horizontal swinging arm 22, that is, in the entire horizontal movement range of the upper feed arm 21. The cam surface is formed so that it always has a constant amount with respect to the rotation angle of 6.

The swing link 24 has its base end connected to a knife drive shaft (not shown) that swings in conjunction with the main shaft of the sewing machine, and swings along the arrow direction A in FIG.

Reference numeral 33 denotes a sewing machine frame; 34, a stepped portion 34a that supports the machine frame 33 so as to be able to slide vertically but not rotate; a step portion 34a that bulges outward in the radial direction at the upper end; 35 is a shaft portion 35a that loosely fits into the upper end of the holder 34 at the lower end, an adjustment shaft having a threaded portion 35b at the upper end, and 36 is a base end fixed to the machine frame 33. 37 is a nut screwed onto the threaded portion 35b above the pedestal 36; 38 is the stepped portion 34a of the holder 34 and the machine frame 33;
This is a buffer placed between the two. 39 is a holding body 34
The support shaft 40 is fixed to the support plane 34b and has an axis that intersects with the cloth feeding direction substantially on the axis of the support shaft 3.
It is a rocking body whose upper end is rotatably supported around 9 and whose lower end is rotatably connected to a rocking link 24. 4
1 and 42 are disposed apart from each other in the cloth feeding direction around the axis of the support shaft 39, and are rotatably supported on the swinging body 40 around an axis parallel to the support shaft 39. The roller 43 that can be engaged with the end face is disposed vertically below the support shaft 39 between the rollers 41 and 42, and is a roller that can be engaged with the lower face of the upper feed arm 21 by sandwiching it between the rollers 41 and 42. The shaft 43a is rotatably supported relative to the eccentric shaft 43a, and the shaft 43a can be stopped from rotating relative to the machine frame. 44 is the holding body 3
4 is a coiled spring that is compressed and arranged between the lower end of the adjustment shaft 35 and the upper end of the rocking body 40 via the buffer body 45.

In such a configuration, the upper feed arm 21 is guided by the rollers 41, 42, and 43 and swings in the horizontal direction by the swinging of the swinging arm 22, and the swinging body 40 is supported by the swinging of the swinging link 24. The upper feed arm 21 swings about the shaft 39, and is pushed up by the rollers 41, 42, and 43 to cause vertical swinging, which causes the upper feed dog 2 at the tip of the upper feed arm 21 to
3 performs four forward motions. The thick part of the cloth is the upper feed dog 23
When the upper feed dog 23 is moved to the tooth portion 23a of the
1 and 42, the swinging body 40 pushes up the holding body 34 against the spring 44, allowing the upper feed arm 21 to rotate. When the upper feed arm 21 returns after the thick part of the fabric has passed, the space between the holder 34 and the machine frame 33 and the spring 44
The impact between the oscillator 40 and the oscillator 40 is buffered by the buffers 38 and 45, thereby preventing vibration and noise. Further, when lifting the presser foot, the upper feed arm 21 (upper feed dog 23) is raised by a certain amount in advance of the presser arm (presser foot 4) by the action portion 18 of the connecting arm 7 that engages with the guide cam 21a.

If play occurs due to dimensional errors between the rollers 41, 42 and 43 and the upper feed arm 24 sandwiched between them, the play can be prevented by adjusting and locking the rotation angle of the shaft 43a. Ru.

As described above, according to this invention, there is a holder 34 that is vertically movably supported with respect to the machine frame above the upper feed arm and always receives a downward elastic force, and a holder 34 that is arranged at the lower end of the holder at the intersection with the cloth feeding direction. A rocking body 40 supported so as to be rotatable around an axis, and a rocking body 40 which is supported in the cloth feeding direction by sandwiching the rotational axis of the rocking body so as to engage with the upper end surface of the upper feeding arm separately at the middle part of the upper feeding arm in the cloth feeding direction. A pair of rotating bodies 41 and 42 are arranged apart from each other and supported on a rocking body so as to be rotatable about an axis parallel to the rotational axis, and an upper feeding arm is sandwiched between the two rotating bodies. A rotary body 43 that can be engaged with the lower end surface and is supported on the rocking body so as to be rotatable about an axis parallel to the rotation axis of the rocking body, and a rotary body 43 that is movable in conjunction with the main shaft of the sewing machine to swing the rocking body. By providing the link 24 that is rotatably connected around an axis parallel to the rotation axis, the spring unlike the conventional one does not act on the vertical and horizontal rocking movements of the upper feed arm. Therefore, even when the sewing machine is operated at high speed, the upper feed dog can always move reliably, making it possible to accurately feed the fabric, clean the seams, and improve the quality of the product. Since the device is smoothly driven by the oscillating motion and the sliding motion of the upper feed arm relative to the holding means, effects such as preventing vibration and noise and extending the life of the device can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the upper feeding device of this embodiment;
The figure is a front explanatory view of the upper feed swing mechanism, and Figure 3 is the second
It is a perspective view of the main part of a figure.

Claims (1)

[Scope of claim for utility model registration] An upper feed dog that is close to the presser foot and faces the throat plate is fixed at the tip, and the base end is linked to the main shaft of the sewing machine and swings along the fabric feed direction, crossing the fabric feed direction. The upper feed arm 21 is rotatable around an axis, the holder 34 is supported vertically movably with respect to the machine frame above the upper feed arm and always receives a downward elastic force, and a cloth is attached to the lower end of the holder. A rocking body 40 is rotatably supported around an axis that intersects with the feeding direction; The upper feed arm is sandwiched between a pair of rotating bodies 41 and 42 which are sandwiched and spaced apart in the cloth feeding direction and supported by a rocking body so as to be rotatable about an axis parallel to the rotating axis, and the rotating bodies. A rotating body 43 that can be engaged with the lower end surface of the upper feed arm and is supported on the rocking body so as to be rotatable about an axis parallel to the rotation axis of the rocking body, and the rotating body 43 is linked to the sewing machine main shaft to swing the rocking body. An upper feed device for a sewing machine, comprising: a link 24 rotatably connected around an axis parallel to a rotation axis of a swinging body;