JPS6314780Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention relates to an improvement of the upper feed mechanism of a sewing machine, and in particular, it is designed to eliminate the influence on the trajectory of the upper feed dog when the thickness of the workpiece is extremely thin. This relates to the upper feed mechanism of a sewing machine.

Conventional techniques and problems In general, a lower feed dog consisting of a main feed dog and a sub-feed dog arranged side by side below the throat plate, a presser foot and a presser foot arranged above the throat plate opposite to the lower feed dog. Sewing machines equipped with an upper feed dog are known.

Conventionally, in this type of sewing machine, when the thickness of the material to be sewn, for example, cloth, changes, the upper feed dog moves up and down directly in conjunction with the up and down movement of the presser foot. That is, when the presser foot moves up and down, the presser arm supporting the presser foot moves up and down, and the movement of the presser arm is directly transmitted to the upper feed dog. However, in conventional sewing machines such as those mentioned above, when the thickness of the fabric is extremely thin, for example 1 mm or less, the lower feed dog protrudes slightly from the top surface of the throat plate (about 0.8 mm on average), which causes the presser foot to By raising the protrusion amount of the lower feed dog, the upper feed dog will rise, and the locus of this upper feed dog will change, causing a decrease in the feed force due to jumping of the upper feed dog, and the upper feed A disadvantage of this method is that the slight movement applied to the tooth drive parts causes wear and the like on the drive parts.

An object of the present invention is to provide a practically useful upper feed mechanism for a sewing machine that overcomes the drawbacks of the prior art as described above.

Means for Solving the Problems In order to solve the problems of the prior art as described above, the present invention provides a mechanism in which, when the lower feed dog protrudes from the upper surface of the throat plate, the movement of the presser foot based on this protrusion moves toward the upper feed dog. This prevents the transmission from occurring to prevent changes in the locus of the upper feed dog.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, an upper feed mechanism of a sewing machine according to the present invention is shown, and the upper feed mechanism is equipped with a presser foot arm 1. As shown in FIG. The other presser arm has a presser foot 3 at one end thereof. This presser foot functions to press a sewing object such as cloth (not shown) placed on the throat plate 30 against the throat plate. This needle plate is attached to the cloth base 40 of the sewing machine in a normal manner and has an opening (not shown) at a portion where the presser foot comes into contact. A lower feed dog 8 is provided below the throat plate. This lower feed dog is arranged opposite to the presser foot 3 and an upper feed dog 14 which will be described in detail later. This lower feed dog consists of, for example, a main feed dog and a sub feed dog.

The other end of the presser foot arm 1 is rotatably supported by the sewing machine main body 2 via a support (not shown) so that the presser foot 3 can come into contact with or move away from the throat plate.

This presser arm 1 is pressed against the presser foot 3 by the first pressing means.
is under elastic action so that it is always in contact with the throat plate 30. This presser means consists of a presser body 5 disposed so as to come into contact with the upper surface of the presser arm, an adjustment screw 4 attached to the sewing machine body 2, a lower end fixed to the upper surface of the presser body, and an upper end fitted into the center hole 4a of the adjustment screw. It consists of an inserted shaft portion 5a and a spring 6 stretched around the shaft portion between the lower end surface of the adjusting screw 4 and the upper end surface of the pressing body 5.

Reference numeral 7 denotes a horizontal oscillator serving as a horizontal motion element, the upper end of which is fixed to a horizontal shaft 9 which oscillates at a constant rate in conjunction with an element which imparts a horizontal component of motion to a known lower feed dog 8.

Reference numeral 10 denotes a vertically swinging body as a vertically moving element, and its base is fixed to a shaft 11 that is interlocked with the main shaft and swings a certain amount in synchronization with the horizontal swinging body 7. Reference numeral 12 denotes an upper feed swinging rod which is arranged parallel to the presser foot rod 1 and whose middle part is connected to the free end of the horizontal swinging body 7 by a shaft 13, which horizontally moves the left part (forward in the cloth feeding direction) in FIG. It is bent to form a support part 12a, and to the support part 12a, the rear part of an upper feed movement rod 15, to which the upper feed dog 14 facing the lower feed dog 8 is fixed, is rotatable about a vertical axis 16. The upper feed swing rod 12 and the upper feed movement rod 15 constitute an interlocking body Z. Note that this interlocking body is connected to the adjusting screw 1 in the same way as the first pressing means described above.
7. A second pressing means consisting of a pressing body 18 and a coil spring 19 constantly applies an elastic force in the clockwise direction in FIG. 1 about the shaft 13.

A movable body 20 is connected to the pressing body 5 of the first pressing means, and is movable up and down along a groove 22 formed in the machine frame 2. 23 has one end connected to the free end of the vertically swinging body 10 via a link 24 and a shaft 25,
It is an actuating body whose middle part is rotatably supported with respect to the movable body 20 by a shaft 26, and a pin 27 provided at the other end.
is arranged below the front of the upper feed swinging rod 12.

The mutual relationship among the horizontal oscillating body 7, the vertical oscillating body 10, and the lower feed dog 8 is approximately as follows.

That is, when the vertical swinging body 10 swings the most in the counterclockwise direction in FIG.
protrudes from the upper surface of the throat plate and is located in the middle of the movement stroke to the left (fabric feeding direction) in FIG. When the lower feed dog 8 moves farthest to the left and sinks from the upper surface of the throat plate, and the vertical oscillator 10 swings the most clockwise, the horizontal oscillator 7 The lower feed dog 8 is located in the middle of the counterclockwise swinging stroke.
sinks from the upper surface of the throat plate and is located in the middle of the movement stroke to the right, and when the horizontal oscillator 7 has swung the most in the counterclockwise direction, the vertical oscillator 10 is in the middle of the movement stroke in the counterclockwise direction. and the lower feed dog 8
has moved most to the right and is about to protrude from the upper surface of the throat plate.

What should be noted is that the presser arm 1 has a first connecting rod 5.
0 is connected, and the second connecting rod 51 is connected to the upper feed arm 15.
is connected. In the illustrated embodiment, the first connecting rod 50 is fixed to the side surface of the pressing body 5, for example by welding, and is therefore indirectly connected to the presser arm. Further, the second connecting rod 51 is indirectly connected to the upper feed arm 15 by being fixed to the movable body 20 by, for example, welding.
The first connecting rod 50 is arranged below the second connecting rod 51. Note that the first and second connecting rods may be fastened with screws or the like instead of welding.

The first connecting rod 50 has a first engagement surface 60;
The second connecting rod 51 has a second engagement surface 70 that is disposed opposite to the first engagement surface so as to be engageable with the first engagement surface. And this first engagement surface 60
A gap 80 is provided between the second engagement surface 70 and the second engagement surface 70 . This gap is set to be at least larger than the amount of protrusion of the lower feed dog from the upper surface of the throat plate 30.

In addition, in FIG. 2, the reference numeral 90 indicates a stopper. This stopper is attached to the sewing machine body 2 so that its position can be adjusted.

In the above mechanism, the lower feed dog 8 slightly protrudes from the upper surface of the throat plate 30 during the feed movement. With this protrusion, the presser foot 3 is pushed upward by the amount of this protrusion plus the fabric thickness. At this time, the upper feed dog 14 performs its own upward feed movement, but due to the gap 80, it does not rise at all despite the rise of the presser foot 3. Therefore, there is no influence on the locus of the upper feed dog.

Effects of the invention According to the invention, as mentioned above, it is possible to eliminate the influence on the trajectory of the upper feed dog that occurs especially when the fabric is extremely thin, and therefore the feed force of the upper feed dog that occurs with the conventional technology can be eliminated. There is a practical benefit in that it can prevent a decrease in the speed and wear of the drive parts of the feed dog.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing a part of the configuration of the upper feed mechanism of a sewing machine according to the present invention, and FIG. 2 is a front view of the main parts. 1... Presser foot arm, 3... Presser foot, 14... Upper feed dog, 15... Upper feed arm, 30... Throat plate, 50...
First connecting rod, 51...Second connecting rod, 60...
First engagement surface, 70...Second engagement surface, 80...
gap.

Claims (1)

[Scope of utility model registration request] A sewing machine having a presser foot, one end of which is rotatably attached to the sewing machine body, and a presser foot attached to the other end, and an upper feed arm, one end of which is rotatably attached to the sewing machine body, and the other end of which is provided with an upper feed dog. In the upper feeding mechanism, a first connecting rod is connected to the presser arm, a second connecting rod is connected to the upper feeding arm, and
The first connecting rod is disposed below the second connecting rod, the first connecting rod is provided with a first engagement surface, and the second connecting rod is provided with a first engagement surface. A second engagement surface that can engage with the engagement surface of the device is provided, and a gap is provided between the first engagement surface and the second engagement surface. Upper feed mechanism of sewing machine.