JPH0424046A - Sewing machine for button in single thread chain stitch manner - Google Patents

Abstract

PURPOSE:To enable surely sewing buttons by causing a final sewing needle to enter a position slightly longitudinally deviated from that of the previously entering needle in a cam groove of a longitudinal feed cam for finely adjusting the longitudinal feed amount. CONSTITUTION:Since a cam groove 20a of a longitudinal feed cam 20 constituting a longitudinal feed mechanism 9 is shaped such that the final sewing needle enters a position slightly longitudinally deviated from that of the previously entering needle, a needle pricking phenomenon in the final needle can be restrained. On the other hand, to form a knot by the final needle in a single loop sewing machine, the needle needs to be dropped on the same position as the previously sewn thread or extremely close thereto. Since a longitudinal feed adjusting mechanism 27 for finely adjusting the longitudinal feed amount of the longitudinal feed mechanism 9 is provided, the final needle dropping position can be adjusted to a position capable of forming the knot while restraining the needle pricking phenomenon. Thus, while the needle pricking phenomenon by the final buttoning needle is prevented, a button can be surely sewn.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention (Industrial Application Field) The present invention relates to a single chainstitch button sewing machine with an improved button holder feeding mechanism for supporting buttons.

(Prior Art) This type of sewing machine is equipped with a sewing needle that performs sewing operations by moving up and down in conjunction with the main shaft of the sewing machine.
The head section is provided with a button holder for holding buttons and a looper for catching needle thread and creating stitches. In a single chainstitch sewing machine, the sewing needle moves up and down so that it repeatedly lands in the same position, so in order to attach a button, the button holder is swung horizontally in synchronization with the main shaft of the sewing machine by a horizontal feed mechanism. This causes the sewing needles to enter adjacent buttons/holes alternately. Therefore, for example, if you finish sewing a button with a total of 8 stitches, the 1st, 3rd...7th odd numbered needles and the 8th needle (last needle) will be in the same position in one buttonhole. and the second buttonhole in the other buttonhole.
The fourth and sixth even-numbered hands will enter the same position.

On the other hand, in order to sew four-hole buttons, this type of sewing machine is also equipped with a vertical feed mechanism that moves the button holder and, in turn, the buttons in the front and back direction. , the sewing needle is automatically moved to the pair of holes in the second row. This vertical feed mechanism is equipped with a vertical feed cam that decelerates and transmits the rotation of the main shaft of the sewing machine, and the cam fits into the cam groove of the vertical feed cam when a predetermined number of stitches have been sewn for the first row of holes. The follower moves, thereby causing the button holder to move the second row of holes on the button to a position corresponding to the sewing needle.

(Problem to be solved by the invention) However, in the conventional single chain stitch button sewing machine described above, the position where the sewing needle drops for each hole is always the same, so the sewing needle pierces the previously sewn needle thread. Needle stick phenomenon is likely to occur. For this reason, when sewing buttons using particularly thick sewing thread or thread with a weak twist, the sewing needle must descend and pierce the previously sewn needle thread again before it pierces the fabric, and then If the louver catches the needle thread, the needle thread will become wrapped around the louver. Then, when the thread trimming knife built in under the throat plate is activated to cut the needle thread after the last needle has finished sewing, the thread trimming knife cannot accurately catch the needle thread, and the thread trimmer cannot cut the needle thread. A problem arises in which a mistake is made and button sewing fails. Also, if the needle thread gets wrapped around the louver like this, you will be forced to open the bed to remove the wrapped thread, or you will have to do the troublesome work of threading the thread through the needle hole again. The productivity of the attachment work will be significantly reduced.

The present invention has been made in view of the above circumstances.

Therefore, it is an object of the present invention to provide a single chain stitch button sewing machine that can prevent the needle stick phenomenon with the final stitch of button sewing and can reliably sew buttons.

[Configuration of the Invention (Means for Solving the Problems) The sewing machine of the present invention includes a sewing needle that performs sewing operations by moving up and down in conjunction with the main shaft of the sewing machine, and a button that is provided below the sewing needle and supports a button. The holder, a horizontal feed mechanism that swings the button holder horizontally in synchronization with the main shaft of the sewing machine so that the sewing needle enters each button hole of the button alternately, and a horizontal feed mechanism that moves the button holder vertically in conjunction with the main shaft of the sewing machine. A sewing machine equipped with a vertical feed mechanism that moves the cam groove of the vertical feed cam constituting the vertical feed mechanism so that the final needle of the sewing operation is placed at a position slightly vertically shifted from the entry position of the previous sewing needle. It is characterized in that it is set in a shape that allows it to enter the vertical direction, and is also provided with a vertical feed amount adjustment mechanism that finely adjusts the vertical feed amount of the vertical feed mechanism.

(Function) The cam groove of the vertical feed cam that constitutes the vertical feed mechanism is shaped so that the last needle of the sewing operation or the previous sewing needle enters the sewing machine at a position that is slightly shifted in the vertical direction. It is possible to suppress the needle stick phenomenon. On the other hand, in the case of a single chainstitch sewing machine, in order to form a knot with the last needle, it is necessary for the needle to fall at the same level or very close to the previously sewn needle thread, but with the above method, the vertical feed mechanism is Since the vertical feed adjustment mechanism is provided to finely adjust the vertical feed amount, the needle drop position of the final needle can be adjusted to a position where a knot can be formed while suppressing the needle stick phenomenon.

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

The overall configuration is as shown in FIG. 5. A sewing machine main shaft driven by a sewing machine motor (not shown) is provided inside the sewing machine main body 1, a bed portion 2 extends long in a cylindrical shape, and an arm portion 3 is connected to the bed. It extends along the upper part of part 2.

A sewing needle 4 that moves up and down in conjunction with the main shaft of the sewing machine is provided at the tip of the arm portion 3, and a well-known louver and thread trimmer (not shown) that move in synchronization with the main shaft of the sewing machine are provided within the bed portion 2. A well-known single chain stitch sewing operation is performed by the cooperation of the sewing needle 4 and the louver, and when the sewing operation for a predetermined number of stitches is completed, the needle thread is cut by the thread trimming knife.

Now, a feed bar 5 is extended from the base of the arm part 3 along the upper surface of the bed part 2, and this is made swingable with respect to the bed part 2 about an adjustment fulcrum 6 and movable in the longitudinal direction. There is. A feed plate 7 is screwed to the distal end of the feed table 5, and a horizontal feed mechanism 8 and a vertical feed mechanism 9 are connected to the base end of the feed table 5 within the sewing machine main body 1, as will be described later. In addition, a holder attachment arm 10 is attached to the feed base 5.
is attached to be rotatable in the vertical direction about a shaft 11, and a button holder 12 is screwed to the tip of this holder attachment arm 10 via a support 11. The button holder 12 is positioned below the sewing needle 4 to support a button (not shown), and has a support groove 12a for inserting and holding the button from the distal end side of the bed portion 2.

The transverse feed mechanism 8 has a detailed structure as shown in FIGS. 6 and 7. Here, the rotation of the camshaft 13 is transmitted from the main shaft of the sewing machine at a reduced speed, and the transverse feed cam 1 provided on the camshaft 13 is
4 rotates in synchronization with the movement of the main shaft of the sewing machine and thus the sewing needle 4. A cross-feed lever 15 is pivotally supported above the cross-feed cam 14 so that its rear end can rotate.
A cam follower 17 that fits into the cam groove 14a of the lateral feed cam 14 is protrudingly provided near the other end of the cam 5. and,
The distal end of the transverse feed lever 15 and the base end of the feed table 5 are connected by a link 18, so that the swinging motion of the transverse feed lever 15 is transmitted to the feed table 5. As a result, when the cross-feed cam 16 rotates, the cross-feed lever 15 swings as shown by arrow A in FIG. 7, and accordingly, the feed table 5 swings as shown by arrow B in the same figure. Such a horizontal feed operation is synchronized with the movement of the main shaft of the sewing machine and thus the sewing needle 4, and one cross feed operation is performed each time the sewing needle 4 drops once, thereby removing the button held in the button holder 12. The sewing needles 4 will alternately enter the two buttonholes forming a pair. In the case of this embodiment, one button attachment is completed by sewing a total of eight stitches.

On the other hand, the vertical feed mechanism 9 has a detailed structure as shown in FIGS. 1 and 2. Here, too, the rotation of the camshaft 19 is transmitted from the main shaft of the sewing machine at a reduced speed, and the vertical feed cam 20 constituting the vertical feed mechanism 9 rotates in synchronization with the movement of the main shaft of the sewing machine and thus the sewing needle 4. Above this vertical feeding cam 20, a vertical feeding arm 21 is rotatably supported around a pivot shaft 21a protruding approximately in the middle thereof.
A cam follower 22 that fits into the cam groove 20a of 0 is provided protrudingly, and an arcuate guide groove 23 is provided on the other end side. A vertical feed adjustment piece 24 is movably housed in the guide groove 23, and a feed rod 25 is connected to the vertical feed adjustment piece 24. The tip end of the feed rod 25 is rotatably connected to a feed link 26 attached to the feed stand 5 about a rotation shaft 25a, and the rear end projects toward the rear of the arm 3 of the sewing machine. Rotation shaft 25 of the above-mentioned feed rod 25
g is provided at a position corresponding to the arcuate center of the guide groove 23 of the vertical feed arm 21, so the rotation operation can be performed by grasping the operation lever part 25b that is integrally extended to the rear end of the feed rod 25. By doing so, the position of the vertical feed adjustment piece 24 within the guide groove 23 can be adjusted. The vertical feed arm 2 unit, the feed rod 25, and the vertical feed adjustment piece 24 described above constitute a vertical feed amount adjustment mechanism 27 for finely adjusting the vertical feed amount in the vertical feed mechanism 9, and the operation lever part 25b If you operate the axis 2 of the vertical feed adjustment piece 24 in the guide groove 23
], since the distances from a will be different, even if the vertical feed arm 21 swings within the same angular range, the vertical feed amount of the feed rod 25 and eventually the feed base 5 will change according to the above distance. Become.

Further, a vertical feed scale 28 as shown in FIG. 4 is provided on the portion of the arm portion 3 from which the operating lever part 25b protrudes, so that the amount of operation of the operating lever 25b can be known. Move the operating lever 25b to the vertical feed scale 28.
If the scale is set to 0, the vertical feed amount becomes 0, and if the scale value is set to a large value, the vertical feed amount increases accordingly.

Further, the vertical feed cam 20 is for sewing a two-hole button, and when the sewing needle 4 sews, for example, 8 stitches,
It is set to rotate so that two buttons can be attached during one rotation. The cam groove 20a of the vertical feed cam 20 is set in the shape shown in FIG. 3 in order to sew a two-hole button. That is, within the angular region XI of half the circumference, the first needle
A long straight portion A1 is formed in the area corresponding to the needle,
Between the 7th needle and the 8th needle (last needle), a diagonal section B1 that is slightly shifted laterally is formed, which is connected to a short straight section A2, and then just before entering the next half-circle angular region X2. A return oblique portion B2 returning to the original straight portion A1 is formed. Note that the angular region X2 for the next half-circle has exactly the same shape as the angular region X1.

Next, the operation when attaching buttons using the sewing machine having the above configuration will be described. First, the operation lever part 25b of the vertical feed total adjustment mechanism 27 is pinched to adjust it to the minute value on the vertical feed scale 28 (for example, 4th N: see the dotted chain line). Then, attach the button to be sewn to the support groove 12a of the button holder 12.
The button holder 12 is then lowered after the cloth is placed on the feed table 5. Next, when the sewing machine motor is started, the sewing machine main shaft rotates and the sewing needle 4 starts to move up and down. At the same time, the cross feed cam 14 rotates in synchronization with the rotation of the main shaft of the sewing machine, and the cam follower 17 fitted into the cam groove 16a reciprocates in the direction of arrow A in FIG. 6 as the center as shown by arrow B in the figure. As a result, the sewing needle 4 alternately enters the pair of buttonholes to perform a sewing operation. As mentioned above, this sewing operation involves a total of 8 stitches, and from the 1st stitch to the 7th stitch, 4 sewing needles are attached to adjacent buttonholes.
The sewing needles 4 enter the buttonhole alternately, and the final eighth needle enters the same buttonhole as the seventh needle.

On the other hand, while such sewing operation is being performed, the vertical feed cam 20 of the vertical feed mechanism 9 also rotates in synchronization with the main shaft of the sewing machine. However, from the beginning of sewing to the seventh needle, the cam follower 22 of the vertical feed mechanism 9 is connected to the cam groove 2 of the vertical feed cam 20.
0a, the cam follower 22 does not move from the beginning of sewing to the seventh stitch, and therefore the feed base 5 does not move in the vertical direction (longitudinal direction). but,
When the 7th stitch is finished and the time comes for the 8th stitch to start sewing, the cam follower 22 begins to move in the diagonal section B1, and when the 8th needle starts sewing, the cam follower 22 moves in the straight section. A2 has been reached, and the feed table 5 has been slightly moved in the direction of arrow C in FIG. Therefore, although the sewing needle 4 of the eighth needle enters the same buttonhole as the seventh needle, its needle drop position is slightly shifted from the seventh needle in the vertical direction.

The needle drop positions from the first needle to the eighth needle are shown in FIG. 8 in order. Here, the first needle, the third needle,
The odd-numbered needle drops of the 5th and 7th needles are in the same position in one buttonhole, and the even-numbered needle drops of the 2nd, 4th, and 6th needles are in the same position in the other buttonhole. Is there?
The positions of the first to seventh needles are shifted in the vertical direction for clarity of the drawing. By letting the 8th needle drop in a slightly different position from the 7th needle in this way,
The sewing needle 4 of the eighth needle does not pierce the needle thread sewn by the seventh needle, and the needle thread is prevented from becoming entangled with the louver below the throat plate. When the sewing operation of the eighth needle is completed, the sewing needle 4 rises to the needle-up position and the thread trimming knife operates to cut the needle thread, or in this case, the thread trimming knife accurately captures the needle thread. Can perform reliable thread cutting.

In addition, in single chain stitch, the last needle (8th stitch) is the needle immediately before it (8th stitch).
If the knot falls too far away from the 7th needle), the knot will not be formed properly.In view of this, in this embodiment, the vertical feed total adjustment is performed to finely adjust the vertical feed amount in the vertical feed mechanism 9. Since the mechanism 27 is provided, by adjusting the mechanism 27, it is possible to obtain the amount of sagging in the vertical direction that can appropriately form a knot while preventing the needle stick phenomenon caused by the eighth needle. Incidentally, the appropriate vertical shift amount is
In the case of this example, it was 0.3 mm.

[Effects of the Invention] As described above, according to the present invention, it is possible to drop the final needle in a sewing operation to a position slightly shifted in the vertical direction from the entry position of the previous sewing needle, and moreover, the amount of shift can be reduced. Can be adjusted to an appropriate value. This provides an excellent effect in that the button can be sewn reliably while preventing the needle stick phenomenon with the final stitch of button sewing.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which Fig. 1 is a perspective view of the main parts, Fig. 2 is a plan view of the same, Fig. 3 is a plan view showing the cam groove of the vertical feed cam developed, and Fig. 4. is a plan view of the vertical feed scale, 5th
The figure is a perspective view of the whole, Figure 6 is a perspective view of the lateral feed mechanism, and Figure 7 is a perspective view of the lateral feed mechanism.
The figure is a plan view of the same, and FIG. 8 is a diagram showing the needle drop positions in order. In the drawings, 4 is a sewing needle, 9 is a vertical feed mechanism, 12 is a button holder, 13 is a horizontal feed mechanism, 20 is a vertical feed cam, 20a is a cam groove, and 27 is a vertical feed amount adjustment mechanism. Applicant: Brother Industries, Ltd.

Claims (1)

[Claims] 1. A sewing needle that performs sewing operations by moving up and down in conjunction with the main shaft of the sewing machine, a button holder provided below the sewing needle to support a button, and a button holder that allows the sewing needle to alternately enter each buttonhole of the button. The button holder is provided with a horizontal feeding mechanism that swings the button holder in the horizontal direction in synchronization with the sewing machine main shaft, and a vertical feeding mechanism that moves the button holder in the vertical direction in conjunction with the sewing machine main shaft, and the vertical feeding mechanism is provided. The cam groove of the vertical feed cam constituting the mechanism is set to a shape that allows the final needle of the sewing operation to enter a position slightly vertically shifted from the previous sewing needle entry position, and the vertical feed of the vertical feed mechanism is A single chainstitch button sewing machine characterized by having a vertical feed amount adjustment mechanism for finely adjusting the amount.