JPH0123434Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a buttonhole sewing device for a zigzag sewing machine.

``Prior Art'' Conventionally, in Japanese Patent Application Laid-Open No. 53-133148, there has been known a device for sewing buttonholes that includes hem sections on both the left and right sides and bar-tacking sections at both front and back ends. A large number of members are required inside the cam that generates the swinging motion of the needle at the bar-tacking portion of the sewing, and the accumulated dimensional errors of each member tend to directly affect the stitches. Furthermore, the buttonhole sewing device disclosed in Japanese Patent Application Laid-Open No. 57-64086 filed by the present applicant has a complicated structure of a lever assembly for controlling the swinging movement of the needle bar during buttonhole sewing. Therefore, the number of parts was even greater than that of the device of the above-mentioned publication.

"Problems to be solved by the invention" The present invention was created in view of the above problems, and it solves the three types of needle oscillation movements that are the biggest technical problem for buttonhole sewing devices. The purpose is to realize a mechanism with a minimum number of members.

``Means for Solving the Problems'' According to the present invention, the sewing needle rotates in conjunction with the main shaft of the sewing machine and generates a swinging motion of the sewing needle at each of the left and right hem stitching parts. A zigzag generating cam formed on one side of the zigzag generating cam with a pair of zigzag cam surfaces corresponding to the overlocking portion facing each other in the radial direction, and a pair of zigzag generating cams facing the one side of the zigzag generating cam and extending around the same axis as the axis of rotation thereof. an amplitude control cam which is rotatably arranged and has an uneven cam surface formed on its outer periphery in order to generate rocking motion of the sewing needle at the bar-tacking portions at both front and rear ends; and the amplitude control cam is synchronized with the zigzag generating cam. A clutch means is provided between the main shaft and the amplitude control cam to rotate or stop the amplitude control cam independently, and is operated as buttonhole sewing is performed, and a clutch means that slides across the rotation axis of the amplitude control cam. a sliding body that is movably attached to a side surface of the amplitude control cam opposite to one side surface of the zigzag generating cam, and is formed such that both ends thereof can protrude outward from the uneven cam surface of the amplitude control cam; , protruding between the pair of zigzag cam surfaces so as to be able to selectively engage with the pair of zigzag cam surfaces of the zigzag generating cam;
The engaging protrusion fixed to the sliding body has an amplitude so that it can engage with each end of the sliding body to which a protruding motion is applied by each of the pair of zigzag cam surfaces or with the uneven cam surface of the amplitude control cam. A buttonhole sewing device for a zigzag sewing machine is provided, comprising a contactor which is constantly biased toward a control cam by an elastic force and is operatively connected to a sewing needle.

"Operation" According to the above configuration, the swinging movement of the sewing needle in the left and right hemlocking parts and the bar-tacking parts at both ends is generated by the zigzag generating cam, the sliding body, and the amplitude control cam, respectively. Only two cam members are required, and the structure of the amplitude control cam or the contact that is always urged toward the sliding body is simplified, so the mechanism for generating three types of sewing needle oscillation movements can be reduced to a minimum number of members. It can be realized with.

``Example'' An example of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view showing the structure of the buttonhole sewing device of this embodiment, and FIG. 2 is a sectional view taken along the line -- in FIG. 1 to explain its operation.

As shown in FIGS. 1 and 2, the hem stitching width operating plate 10, which constitutes a sliding body, is slidable in a groove 12 formed on the side surface of the buttonhole width cam 11. . The actuating plate 12 is provided with pins 13 and 15 forming engagement protrusions,
A pin 13 fixed perpendicularly to one side of the actuating plate 10 is engaged with a groove cam portion 1 formed on one side of the amplitude cam 14. A pin 15 fixed perpendicularly to the other side of the actuating plate 10 is fitted into a long hole 16 of the buttonhole swing width cam 11.

Further, a buttonhole swing width cam 11 is screwed and fixed to a shaft 18 extending through a central elongated hole 17 of the operating plate 10.

Both ends 10A and 10B of the actuating plate 10 have a small amount △ shown in FIG. It is configured so that it can protrude outward by T1 and △T2, respectively.

A drive gear 3 fixed to a main shaft of a sewing machine (not shown) is meshed orthogonally with a swing width and feed cam gear 4. The swing width and feed cam gear 4 is rotatably fitted to a shaft 18, and the swing width cam 14 is fixedly installed at one end of the cam gear 4, and a buttonhole is formed on the outer periphery of the swing width cam 14. A swing width cam portion 5 for patterns other than sewing is formed. Further, the other end of the cam gear is integrally formed with a small diameter portion having a large number of grooves 6 on the outer periphery and a feeding cam portion 7 for patterns in which feeding movements other than buttonhole stitching are controlled.

The shaft 18 has large diameter, medium diameter, and small diameter cam surfaces 19A, 1 on the outer periphery at the near end in FIG.
A feed cam 19 on which 9B and 19C are formed is fixed with screws. A clutch pawl 20 is rotatably mounted on the side surface of the feed cam 19 by means of a caulking pin 21. The tip 2 of the clutch pawl 20
0A has a width that allows it to be engaged with and detached from the groove portion 6,
The rear end 20B of the clutch pawl 20 is adapted to selectively abut control surfaces 22A, 22B formed on a forked pawl control plate 22. The swing width and feed cam gear 4, the clutch pawl 20, the pawl control plate 22, etc. constitute a clutch means.

The grooved cam portion 1 forming the zigzag generating cam has a pair of zigzag cam surfaces 1A, 1 as shown in FIG.
B are radially opposed to each other.

The stitch width contactor 8 is connected to the needle bar via a well-known needle bar swinging mechanism, and is connected to each end 10A, 10B of the hem stitch amplitude operating plate 10 or the buttonhole amplitude cam 11. The buttonhole swing width cam 11 is configured so as to be able to engage with the uneven cam surface 2.
It is constantly urged toward by elastic force. On the outer periphery of the feed cam 19, a feed contact (not shown) operatively connected to a feed adjuster is provided on the outer periphery of the feed cam 19.
9 is disposed so as to selectively abut on cam surfaces 19A, 19B, and 19C on the outer periphery.

"Operation" Next, the operation of the buttonhole sewing device configured as described above will be explained.

The swing width contact 8 is the buttonhole swing width cam 11
When buttonhole stitching is selected by the feed contact facing the feed cam 19, the pawl control plate 22 is operated in conjunction with a well-known presser foot device.
The clutch pawl 20 is operated by one control surface 22B, and the tip 20A of the pawl 20 touches the feed cam portion 7.
It fits into the groove 6 of. As a result, the feed cam 19 rotating together with the pawl 20 is driven by the drive gear 3 rotated by the main shaft of the sewing machine via the cam gear 4, the feed cam portion 7, the groove portion 6, and the pawl 20, and starts rotating. At this time, the feed contact is connected to its feed cam 1.
Since it is in contact with the medium-diameter cam surface 19B of 9, the cloth feed of the sewing machine is in a state of zero.

As the feed cam 19 rotates, the shaft 1
8 starts rotating in conjunction with the main shaft of the sewing machine, and the buttonhole width cam 11 is rotated by the shaft 18. When buttonhole sewing is started, the stitch width contactor 8 is in contact with the buttonhole stitch width cam 11 in the state shown in FIG. 2a. In other words,
The contact 8 is located at the end 1 of the hem stitch width operating plate 10 which is slightly higher than the concave portion of the buttonhole width cam 11.
0A, and the sewing needle of the sewing machine is at the position indicated by the symbol G in FIG. 2a. When the buttonhole width cam 11 rotates counterclockwise as shown by the arrow L, the width contactor 8 contacts the convex portion and the concave portion of the width cam 11 alternately, as shown in FIG. 2d. The needle of the sewing machine is swung to its maximum bartack width in range AB, and the lower bartacked area is formed on the workpiece cloth at feed O and maximum amplitude.

When the buttonhole width cam 11 rotates approximately 180 degrees to the position shown in FIG. The pin 13 moves in the groove 12 of the swing width cam 11 to the right in FIG.
come into contact with. Meanwhile, by that time, the feed cam 19 has also rotated approximately 180 degrees, the well-known feed contactor is in contact with the large diameter cam surface 19A of the feed cam 19, and the workpiece cloth feed teeth perform a reverse feed operation.

The tip 20 of the claw 20 is controlled by the action of the claw control plate 22.
Since A comes out of the groove 6 of the feed cam portion 7, the feed cam 19 stops, and the feed cam 19 and shaft 18
The buttonhole swing width cam 11, which is interlocked via the buttonhole swing width cam 11, also stops. Only the amplitude cam 14 rotates as the cam gear 4 rotates, and the groove cam portion 1 on the side surface of the amplitude cam 14 rotates.

Then, the zigzag cam surface 1A of the grooved cam portion 1
As the pin 13 rotates, the pin 13 is driven along the unevenness of the zigzag cam surface 1A, and the amplitude contactor 8
is shown in FIG. 2 e,
It is swung left and right by the pin 13 as shown in f. Since the swinging movement of the swing width contactor 8 is transmitted to the sewing needle via a well-known needle bar swinging mechanism, a stitched area on the left side of the buttonhole is formed in the workpiece cloth with a width range CD. Note that the seam at the C portion is provided by the uneven cam surface 2.

When the formation of the overlocking part of the required length that matches the size of the button is completed, the clutch pawl 20 is rotated by actuating the pawl control plate 22 by a member that comes into contact with a well-known buttonhole presser foot. Then, the tip 20A of the clutch pawl 20 engages with the groove 6 of the feed cam portion 7, so the feed cam 19 starts rotating again, and the buttonhole swing, which is interlocked with the feed cam 19 via the shaft 18, starts rotating. The width cam 11 also starts rotating. As the feed cam 19 rotates, the feed contact comes into contact with the medium-diameter cam surface 19B of the feed cam 19, so that the feed of the feed dog becomes zero. Further, by the rotation of the buttonhole width cam 11, as shown in FIG. 2c, the width contactor 8
, comes into contact with the uneven cam surface 2 on the outer periphery of the buttonhole amplitude cam 11, so the sewing needle of the sewing machine is swung at an amplitude within the range EF corresponding to the convex and concave portions of the uneven cam surface 2, and the sewing machine is machined. The bar tacking part above the buttonhole is sewn on the cloth with a large amplitude and a feed amount of 0.

When the buttonhole swing width cam 11 is rotated 180 degrees counterclockwise from the state shown in FIG.
As shown in FIG. 2, the stitch width contactor 8 contacts the end portion 10A of the hem stitch stitch width operating plate 10, and the pin 13 contacts the inner zigzag cam surface 1B. Since the feed contact comes into contact with the small-diameter cam surface 19C of the feed cam 19 in FIG. 1, the feed teeth perform a normal feed motion and the work cloth is fed normally. Further, the rear end 20B of the clutch pawl 20 and the pawl control plate 22
Due to the contact with the control surface 22A of the clutch pawl 20, the tip 20A of the clutch pawl 20 comes out of the groove 6 of the feed cam portion 7, so that the rotation of the feed cam 19 is stopped, and as a result, the rotation of the buttonhole width cam 11 is also stopped. Ru. Since the swing width cam 14 alone is rotated by the drive gear 3 via the cam gear 4,
The grooved cam portion 1 on the side surface of the amplitude cam 14 is rotated.

Therefore, as the hem stitching amplitude actuating plate 10 is pressed to the right in FIG. By being reciprocated left and right by the unevenness of the inner zigzag cam surface 1B,
The buttonhole width cam 11 is slid from side to side within the groove 12 as shown in FIGS. 2a and 2b. Then, the amplitude contactor 8 that has come into contact with the end portion 10A of the actuating plate 10 is swung as the actuating plate 10 slides left and right, and by oscillating the sewing needle of the sewing machine, the stitching width contactor 8 is attached to the work cloth. An overedge area is formed on the right side of the hole. In other words, when the end portion 10A of the actuating plate 10 retreats to the right as shown in FIG. When the end portion 10A of the actuating plate 10 moves forward to the left as shown in , a seam is formed at the right end of the right side edge portion as shown by symbol H.

"Other Embodiments" In a sewing machine that sews a pattern with a large number of stitches, the stitch width and the reduction ratio between the feed cam gear 4 and the drive gear 3 may be increased to about double.
In such a case, the main shaft of the sewing machine will be rotated twice as much to sew the buttonhole, so the uneven cam surface 2 formed on the circumference of the buttonhole swing width cam 11 will be rotated for 18 stitches, for example. It is also possible to increase the number of stitches to a certain degree, and use the 12 stitches of the uneven cam surface 2 to form the upper and lower bar-tacking parts, and use the remaining 6 stitches to form part of the buttonhole edge part. Further, in this case, it is possible to implement the device favorably by forming the actuating plate forming the sliding body into a curved shape.

``Effects'' As described above, the buttonhole sewing device of the present invention has a sliding body attached to the side surface of the amplitude control cam, so that the buttonhole sewing device can be constructed thinly, and the contactor structure Because it is easy to do this, it is possible to realize three types of sewing needle oscillating motion generating mechanisms for the left and right edge hem portions and bar tacking portions using a minimum number of materials, increasing the accuracy of the seam formation position. Furthermore, there are many excellent effects such as improved operational reliability and durability of the buttonhole sewing device, and reduced manufacturing costs.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing the construction of a buttonhole sewing device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line -- in FIG. 1 to explain its operation. 1... Grooved cam portion, 1A, 1B... Zigzag cam surface, 2... Uneven cam surface, 3... Drive gear, 4...
Stitch width and feed cam gear, 6...Groove portion, 8...Stitch width contactor, 10...Edge sewing swing width operating plate, 11
...Buttonhole width cam, 13...Pin, 1
8...shaft, 19... feed cam, 20... clutch pawl, 22... pawl control plate.

Claims (1)

[Scope of Claim for Utility Model Registration] A zigzag sewing machine that can automatically sew buttonholes including overlocking parts on both the left and right sides and bar tacking parts on both front and back ends, which rotates in conjunction with the main shaft of the sewing machine, A zigzag generating cam in which a pair of zigzag cam surfaces corresponding to each hemlocking part are formed on one side facing each other in the radial direction in order to generate a swinging motion of a sewing needle in each of the hemlocking parts; and the zigzag generating cam. is arranged to be rotatable around the same axis as the axis of rotation of the sewing machine, and has an uneven cam surface formed on the outer periphery to generate a rocking movement of the sewing needle at both bar tacking parts. a control cam, and a control cam provided between the main shaft and the amplitude control cam in order to rotate the amplitude control cam in synchronization with the zigzag generation cam or to stop it independently, and is activated when buttonhole sewing is performed. a clutch means mounted on a side surface of the amplitude control cam opposite to one side surface of the zigzag generating cam so as to be able to slide across the rotational axis of the amplitude control cam, and having both ends thereof a sliding body formed to be able to protrude outward from the uneven cam surface, and a sliding body that protrudes between the zigzag cam surfaces so as to be able to selectively engage with the pair of zigzag cam surfaces of the zigzag generating cam, and a sliding body that is formed to protrude outward from the uneven cam surface; The fixed engaging protrusion is oriented toward the amplitude control cam so as to be able to engage with each end of the sliding body to which a protruding motion is applied by each of the pair of zigzag cam surfaces or with the uneven cam surface of the amplitude control cam. What is claimed is: 1. A buttonhole sewing device for a zigzag sewing machine, characterized in that the buttonhole sewing device is provided with a contactor which is constantly biased by an elastic force and is operatively connected to a sewing needle.