JPS62607Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a known buttonhole sewing attachment that is attached to an ordinary straight stitch sewing machine to sew buttonholes.

In this type of attachment, a base frame of the attachment is attached instead of the presser foot of the sewing machine, and an actuating plate attached to this attachment is moved by a drive mechanism that is linked to the vertical movement of the needle bar of the sewing machine. This machine sews buttonholes using a sewing machine needle that moves the fabric held down by a frame together with an operating plate and creates stitches at fixed positions.

In this type of attachment, a circular cam is rotatably attached to a cam holder fixed to the actuating plate.
An oval endless cam groove is formed by any one of a plurality of U-shaped cam grooves of different lengths provided radially on this circular cam and one U-shaped cam groove fixed to the cam holder. A pinion gear provided on the base frame is meshed with an internal gear formed in the needle bar, and the pinion gear is rotated by a drive mechanism linked to the needle bar to move the actuating plate.

Therefore, when sewing a buttonhole, it is necessary to turn the circular cam to match the cam groove of the desired length with the cam groove of the cam holder, and then fix the circular cam to the cam holder. It is an object of the present invention to provide a circular cam fixing device that can extremely easily fix and release such a circular cam to a cam holder.

The details of this invention will be explained below based on the attached drawings.

In the figure, reference numeral 1 denotes a base frame, and the rear end thereof has a mounting portion 2 for attaching to a presser bar. Further, the entire lower part of the base frame 1 is covered with a cover 3 having a bottom, and the rear part is also covered with a cover 4.

Reference numeral 5 denotes an actuating plate attached to the base frame 1 so as to be able to move freely in the front-rear and left-right directions.The rear part of the actuating plate 5 is located at the bottom of the base frame 1, but the front part is bent upward and is attached to the base frame 1. The cam holder 6 comes out upward from the opening in the middle of the frame 1 and bends forward, and is placed on the base frame 1. A cam holder 6 is fixed here, and a disc-shaped cover part 7 is integrally formed in front and behind it. A circular cam 8 is rotatably attached to the lower part of the cover part 7 by a shaft 9.

As shown in FIG. 3, a plurality of U-shaped cam grooves 10 of different lengths are formed on the lower surface of the circular cam 8.
One U-shaped cam groove 11 is formed in the cam holder 6, and when the circular cam 8 is rotated and the desired cam groove 10 is aligned with the cam groove 11, an oval endless cam groove a of the desired length is formed. It is something that will be done. Further, internal gears are provided in each of the cam grooves 10 and 11 so that an endless internal gear b is formed along the endless cam groove a, and a pinion gear 12 is rotatably attached to the base frame 1. meshes with internal gear b, and gear 12
The upper center pin 12' is arranged to mesh with the cam groove a.

Reference numeral 13 denotes a cylindrical part formed integrally with a part of the cover part 7, on which the engaging pin 14 is attached so as to be rotatable and movable up and down, and a spring 15 pushing the pin 14 downward is attached.
Install. Also, there is a knob 16 at the upper end of the pin 14.
This knob 16 is cap-shaped and is placed over the outside of the cylindrical portion 13 so as to be rotatable and movable up and down.

A cam surface 17 is formed at the upper end of the cylindrical portion 13, as shown in FIGS. 5 and 6, and has a downward slope in a clockwise direction over a predetermined angle range (for example, about 100 degrees).
A cam contact portion 18 that contacts the cam surface 17 is provided near the outer periphery of the lower surface of the top of the knob 16.

On the circular cam 8, an engagement hole 19 is provided for each cam groove 10, into which the engagement pin 14 engages.

The cam holder 6 also has a window 20 for displaying the buttonhole dimensions on the circular cam 8 as shown in FIG. will be established.

Reference numeral 22 in Figures 1 and 2 is a drive lever that is swingably attached to the base frame 1, and its two-pronged portion at the tip engages with a sewing machine needle fixing screw attached to the needle bar of the sewing machine (not shown). The movement of the lever 22 is transmitted to the actuating plate 5 through an appropriate interlocking mechanism to make the actuating plate 5 swing from side to side, and the pinion gear 1
2 is intermittently rotated in a fixed direction.

A work presser frame 23 is attached to the lower rear end of the actuating plate 5, and a rubber plate 24 is attached to the lower surface of this frame. The lower surface of this rubber plate 24 is formed with unevenness to prevent slipping between the rubber plate and the cloth. Note that 25 in FIGS. 1 and 2 is an operating lever for manually feeding the pinion gear 12.

The operation of the buttonhole sewing attachment shown in the above embodiment will be explained below.

First, the attachment part 2 is fixed to the presser foot instead of the presser foot of the sewing machine, and the two prongs of the drive lever 22 are engaged with the sewing machine needle fixing screw of the needle bar, so that the cloth presser frame 23 is moved toward the front, that is, when sewing is started. turn towards the person.

Also, by turning the circular cam 8, the desired cam groove 10 is brought into the working position, that is, the cam groove 11 of the cam holder 6 is connected.
When the operating lever 25 is operated to rotate the pinion gear 12 and the operating plate 5 is moved together with the circular cam 8 to bring the operating plate 5 to the most advanced position, a part of the pinion gear 12 is moved out of the arcuate window 21. Since you can see it, stop operating the lever 25 at this position. As a result, the pinion gear 12 is rotated by the circular cam 8.
has separated from the cam groove 10.

Next, when the knob 16 is rotated to the left, the cam contact portion 18 of the knob 16 rises along the cam surface 17, and the engagement pin 14 integrated with the knob 16 is moved against the spring 15.
The circular cam 8 rises against the force and disengages from the engagement hole 19 of the circular cam 8.

In this state, turn the circular cam 8 by hand, stop it with the desired size displayed on the display window 20, and turn the knob 16 to the right, the cam contact portion 18 will descend along the cam surface 17 and engage. The dowel pin 14 engages with the engagement hole 19 of the circular cam 8 and locks the cam 8.

After setting the circular cam 8 as described above, placing a cloth under the presser foot frame 23 and lowering the feed dog to the non-operating position, when the sewing machine starts operating, the operating plate 5 swings from side to side. The cloth is moved left and right to perform zigzag stitching, and the pinion gear 12 rotates while meshing with the internal gear b of the endless cam groove a, moving the actuating plate 5 and sewing the desired buttonhole.

This invention is an attachment that performs the above-mentioned functions, and the circular cam 8 is fixed and released by rotating the knob 16 provided on the cover portion 7 of the cam holder 6, making it easy to operate. That is, the engagement pin 1 that engages with the engagement hole 19 of the circular cam 8
Since a downward force is applied to the engagement pin 14 by the spring 15, it is difficult to directly pull up the engagement pin 14 against the force of the spring 15, and it will return to its original position when you release your hand. However, in the case of this invention, the engagement pin 14 moves up and down just by rotating the knob 16.
In addition, a flat part 26 is provided at the upper end of the cam surface 17 so that the engagement pin 14 can be kept raised, and the circular cam 8 can be rotated by releasing the knob 16. This has the advantage that the ten selection operations can be performed extremely easily.

[Brief explanation of the drawing]

Fig. 1 is a side view of an attachment that implements this invention, Fig. 2 is a plan view, Fig. 3 is a bottom view taken along line A-A in Fig. 1, and Fig. 4 is a -B-- in Fig. 2. FIG. 5 is an enlarged sectional view taken along line B, FIG. 5 is an enlarged partially cutaway plan view of the knob portion, and FIG. 6 is an exploded perspective view of the knob portion. DESCRIPTION OF SYMBOLS 1... Base frame, 5... Operating plate, 6... Cam holder, 7... Cover part, 8... Circular cam, 10,1
1...Cam groove, 12...Pinion gear, 13...
Cylindrical portion, 14... Engagement pin, 15... Spring, 18
...Cam contact portion, 19...Engagement hole, a...Endless cam groove, b...Internal gear.

Claims (1)

[Scope of utility model registration request] The base frame attached to the presser foot of the sewing machine is equipped with an operating plate that moves back and forth and left and right while swinging left and right with the cloth in conjunction with the needle bar of the sewing machine, and a pinion gear that rotates in conjunction with the needle bar of the sewing machine. The operating plate is provided with a rotatable circular cam and a cam holder having a cover portion that overlaps the cam, and one of the plurality of cam grooves formed on the circular cam and one cam provided on the cam holder are provided on the operating plate. In a buttonhole sewing attachment in which the pinion gear is engaged with an internal gear of an endless cam groove formed by a groove, and the rotation of the pinion gear moves the actuating plate back and forth and left and right together with the cloth, the cover part provided on the cam holder. A cylindrical part is provided on the top, and a locking pin that engages with the engagement hole provided for each cam groove on the circular cam when descending is attached to this cylindrical part so as to be able to move up and down, and a spring that presses down this pin is attached to the cylindrical part. A cam surface is provided on the upper end of the cylindrical portion and on the opposite side of the knob fixed to the upper end of the pin, and a cam surface that raises the pin and disengages it from the engagement hole of the circular cam when the knob is rotated in a certain direction at a certain angle. Circular cam fixing device with cam contact area.