JPS605900Y2 - Sliding buttonhole foot on sewing machine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sliding buttonhole presser used for sewing buttonholes on a sewing machine, and is intended to allow buttonholes to be sewn accurately and beautifully.

Conventionally, when sewing buttonholes with a sewing machine, a sliding buttonhole presser as shown in FIG. A presser foot consisting of a slider 2 that is fitted onto the foot and is pressed against the cloth by the presser foot pressure applied to the presser foot bar and slides along with the cloth in the cloth feeding direction is often used. If this is done, a correct buttonhole stitch with parallel left and right stitches as shown in the second figure may result in a defective buttonhole stitch in which the left and right stitches intersect as shown in the third figure.

To explain this factor with reference to FIG. 4, 3 is the slider 2.
A feed dog 4, which clamps the cloth and imparts a cloth feeding motion to the cloth by cooperation with the feed dog 4, swings about a pivot point P on the feed table to which the feed dog is attached.

When the feed dog 3 moves up and down due to the rocking motion of the feed base 4, the feed dog 3 and the feed base 4 move as shown by the dotted line due to the presser pressure F of a known presser bar applied to the top surface of the feed dog 3. As a result, the top surface of the feed dog 3 protruding from the upper surface of the throat plate 6 sinks by an amount a.

Due to this deformation of a, the feed table 4 moves around the pivot point P, and the tooth tip of the feed dog 4 moves laterally by an amount b.

The magnitude of this lateral feed amount varies depending on a vector determined by the rigidity of the feed dog 3 and the feed base 4 and the relative position of the tooth tip of the feed dog 3 with respect to the pivot point P of the feed base 4.

This horizontal feed amount is the cloth feed movement of the feed dog 3 - the cloth is applied to each stitch of cloth due to the cloth feed movement of the feed dog 3, which is the horizontal component of the presser foot pressure FH
Then, as shown in the third diagram, the cloth is fed in an incorrect direction that is inclined with respect to the correct cloth feeding direction A-A.

In addition, in the case of buttonhole sewing, the stitches are made up of forward sewing on one side and backward sewing on the other side, and approximately the same cross-feeding force FH acts on the fabric during each sewing. As shown in Figure 3, the left and right stitches intersect, resulting in a defective buttonhole stitch.

This horizontal feeding phenomenon of the cloth is caused by the feed dog 3 and the feed base 4.
This can be solved by significantly increasing the rigidity of the mechanism, but in reality there is no room for reinforcement due to space constraints with other mechanisms and the cloth feeding movement of the feed dog 3 and the feed table 4 themselves.

In view of the above-mentioned circumstances, this invention has been developed to eliminate the shortcomings, and as a result, it has a simple structure that eliminates the phenomenon of cross-feeding of cloth, thereby achieving accurate and beautiful buttonhole stitches. A sliding buttonhole presser has been developed, and examples thereof will be described below with reference to the drawings.

Reference numeral 11 denotes a synthetic resin presser foot consisting of a flat plate portion 11a and two rising portions 11b, between which a connecting pin 12 lying horizontally is planted.
The presser foot is removably attached via a connecting pin 12 to a mounting body (none of which is shown) fixed to a known presser bar.

Reference numeral 13 indicates a notch for monitoring the buttonhole stitch formed at the center of the left end of the flat plate portion 11a of the presser foot 11; It is a narrow projecting piece formed to protrude from the end face to the vicinity of the right end face of the flat plate portion 11a, and its top face is set to be the same as or slightly lower than the bottom face of the height contact piece 22 of the slider 2, which will be described later.

Reference numeral 15 denotes an arrow-shaped position specifying portion marked on the upper surface of the flat plate portion 11a of the presser foot 11.

The slider that fits into this presser foot 11 and slides in the cloth feeding direction is exactly the same as the known slider 2 shown in FIG.
To explain the details, reference numeral 16 denotes a guide piece which is slightly folded upward and inward in the shape of a cross-sectional opening on both the front and rear end surfaces. The distance between the front and rear end surfaces of 11a is set to be equal to or slightly larger than 1.

Further, the width of the sliding groove 16a is set to be slightly larger than the thickness of the flat plate portion 11a of the presser foot 11.

17 is a longitudinal needle drop hole drilled in the middle of the slider 2 in order to sew buttonhole stitches in the longitudinal direction; 18;
19.20 is a left side wall bent upward at right angles to the left end surface of the slider 2, and 19.20 is a gripping piece and a tongue piece formed at the center of the left and right end faces of the slider 2; It is set so that the bent part of the core cord (not shown) is hooked, and the open part of the core cord is clamped by the clamping piece 19.

Reference numeral 21 denotes a scale section marked on the top surface of the guide piece 16 on the rear side of the slider 2. By aligning the position specifying section 15 of the presser foot 11 with an appropriate position on this scale section, the sewing start position for buttonhole sewing is determined. , which determines the size of the buttonhole stitch.

Reference numeral 22 denotes a high contact piece made of a material having a relatively large coefficient of friction, such as rubber or synthetic resin, which is attached to the bottom surface of the slider 2.

Therefore, in order to combine the presser foot 11 and the slider 2,
After fitting the flat plate portion 11a of the presser foot 11 into the sliding groove 16a of the guide piece 16 of the slider 2, the right end surface of the slider 2 is folded upward at a right angle, and the right side wall 23 and the presser foot 11 of the slider 2 are folded upward.
This is done by preventing it from falling off.

The present invention is constructed as described above, and when sewing buttonholes, the cloth held between the height contact piece 22 of the slider 2 and the feed dog 3 moves together with the slider 2 as the feed dog 3 moves to feed the cloth. Move in the cloth feeding direction.

As a first step, the seam C on the right side shown in the second figure is constructed by forward (and backward) cloth feeding, but at this time, as shown in the ninth figure, the cloth S is subjected to the cross-feeding force as described above. FH
However, the seam C that has already been sewn on the right side surface 14a of the protruding piece 14 comes into contact with the cloth S, and the movement of the cloth S in the cross-feeding direction is restricted.

Next, the front part tuck d of the second step is arranged, and the left side seam e of the third step is arranged by backward (or forward) cloth feeding. As with when the fabric S is set up, it tries to move to the left by the cross-feeding force FH, but the right side seam C that has already been sewn comes into contact with the right side surface 14a of the protruding piece 14, and the cloth S moves in the cross-feed direction. movement is restricted.

Finally, after the fourth step, the buttonhole stitch is completed by forming the part tuck f.

As described above, according to the present invention, when sewing buttonholes with a sliding buttonhole presser consisting of a presser foot and a slider, the protrusion provided on the bottom of the presser foot restricts the movement of the cloth in the cross-feeding direction. This invention is extremely useful in practice, as it allows accurate and beautiful buttonhole stitches, and has a simple structure.

[Brief explanation of the drawing]

Figure 1 is a slope view of a conventional sliding buttonhole presser, Figure 2 shows a good buttonhole seam, Figure 3 shows a bad buttonhole seam, and Figure 4 shows that the feed dog and feed base are attached to the presser foot. An explanatory diagram showing the state of deformation due to pressure, FIG. 5 is a slope view of the sliding buttonhole presser foot according to the present invention, FIG. 6 is a slope view of the presser foot according to the present invention, and FIG. 7 is the back side of FIG. 6. FIG. 8 is a longitudinal sectional view including the axis of the coupling pin in FIG. 5, and FIG. 9 is an explanatory view showing the action of the protruding piece of the presser foot. In the figure, 2 is a slider, 11 is a presser foot, 14 is a protruding piece, 16
2 is a guide piece, and 22 is a height contact piece.

Claims (1)

[Scope of utility model registration request] a presser foot 11 attached to a mounting body fixed to the presser bar;
A sliding button for a sewing machine comprising a guide piece 16 that is fitted in the presser foot so as to be visible and has a rectangular needle drop hole, and a slider 2 that has a height contact piece 22 on the bottom surface that comes into contact with the cloth. In the hole presser, the presser foot 11
The slider 2 extends in the longitudinal direction of the substantially central portion of the bottom surface of the slider 2.
A sliding buttonhole presser for a sewing machine, characterized in that a narrow protrusion 14 is provided that can protrude downward to approximately the same height as the height contact piece 22 through the needle drop hole.