JPS61100291A - Yarn holder in cycle sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a thread holding mechanism in a cycle sewing machine (lockstitch button sewing machine, bar tacking sewing machine).

(Prior Art) Conventionally, various sewing machines have been proposed for this type of cycle sewing machine, including lockstitch and single chain stitch button attachment, but in particular, lockstitch button attachment has been proposed for sewing machines that use the thread of the needle thread at the beginning of sewing. The ends remain on the top surface of the button, significantly reducing the quality and commercial value of the sewn product, and it is also necessary to cut and remove the remaining threads as post-processing.

Previously, in Japanese Utility Model Application Publication No. 57-166879, a device was proposed to prevent upper thread from being pulled out in a button sewing machine. When the needle drops, the thread presser moves with the movement of the needle plate and releases the thread presser, so the thread presser is not completely pressed.

(Problems to be Solved by the Invention) The present invention solves the conventional problems such as thread remaining on the upper surface of the button and incomplete thread pressing, and makes sure that the end of the thread at the beginning of sewing is attached to the fabric. It is an object of the present invention to provide a thread holding mechanism for a cycle sewing machine that is capable of keeping the thread on the back side and ensuring a necessary thread length.

[Structure of the invention]

(Means for Solving the Problems) Therefore, the present invention provides a feed cam shaft that rotates once per cycle of a cycle sewing machine, a thread holding cam fixed to the cam shaft and having a protrusion on the outer peripheral surface, and a thread holding cam that is fixed to the cam shaft and has a protrusion on its outer peripheral surface. A thread holding cam lever that has a pin at one end that is always pressed against the outer peripheral surface of the cam and is rotatable around a fulcrum, a movable thread holding plate that is provided on the needle plate so that its tip is located at the needle drop point, and a link mechanism disposed between the movable yarn holding plate and the yarn holding cam lever, which reciprocates the movable yarn holding plate by the rotational movement of the cam lever; and a link mechanism disposed opposite to the tip of the movable yarn holding plate to hold the yarn. a fixed thread holding plate overlapping the upper surface of the movable thread holding plate, and while the pin of the thread holding cam lever is positioned on the protrusion of the thread holding cam, both the threads are Hold the thread at the tip of the holding plate, and adjust the circumference of the protrusion so that the pin of the thread holding cam lever rests on the protrusion of the thread holding cam from the beginning of the second stitch to the end of the fourth stitch. It has a configuration in which the surface length is set, and this is used as a means to solve the problem.

(Function) Now, the thread holding cam is rotating, and at the beginning of the second stitch after the sewing machine performs the start operation, that is, when the thread length of the needle thread is shortened, the protrusion of the thread holding cam The pin of the thread holding cam lever is mounted and the cam lever is rotated counterclockwise. Due to this rotation, the movable thread holding plate moves via the link mechanism to hold the thread with the fixed thread holding plate, and this thread holding is continued until the end of the fourth stitch, and then released.

(Example) An example of the present invention will be described below with reference to the drawings. Figs. 1 and 2 are a plan view and a side view of a thread holding mechanism showing an example of the present invention, and 35 is a one cycle of a cycle sewing machine. A thread holding cam 4 is attached to the end of the feed cam shaft using a set screw 2 through a washer 3, and the cam 4 is provided with a protrusion 4a on its outer periphery.

Reference numeral 6 denotes a thread holding cam lever, which has an inverted T-shape, the lower center part of which is pivoted to a single cam lever 8 by means of a thread holding cam lever set screw 5, and a cam lever at one end that is always in contact with the outer periphery of the thread holding cam 4. A pin screw 12 is attached using a locking nut 13. A cam lever stopper 10 attached to one cam lever 8 with a set screw 9 is in contact with the upper surface of the other end to hold the thread holding cam lever 6 in the position shown in FIG.

7 is a regular screw for fixing one cam lever 8.

Further, a thread holding link 14 is connected to the thread holding cam lever 6 by a cam lever pin screw 11, and a hook-shaped corner of the thread holding link 14 is connected to a set screw 5a to connect the thread holding link 14 to the thread holding cam lever 6.
The thread holding intermediate lenony 48 is supported at the other end of the link 14 by a set screw 5b. The thread holding intermediate lever 18 is pivotally supported on the frame 39 by a set screw 17, and is pulled by a return screw 34 to urge the thread holding link 14 in the direction opposite to the arrow in FIG. The other end of the return spring 34 is connected to a spring hook 15, and the spring hook is attached to the frame by a locking bolt 13a. Further, 16 is a pin for a spring hook, and 1 is a forward link set screw.

When the sewing machine performs the start operation, the thread holding cam 4 begins to rotate in the direction of the arrow in FIG. When the portion 4a lifts the pin screw 12 of the thread holding cam lever 6, the cam lever 6 rotates counterclockwise about the set screw 5.

Therefore, attach 7 ljs to the thread holding cam lever 6 with the pin screw 11.
The thread retaining link 14, which is in the 8th position, moves in the direction of the arrow in FIG. 1 against the return spring 34. That is, the rotational movement of the thread holding cam lever 6 is converted into linear movement by the thread holding link, and the intermediate lever 18 rotates clockwise around the set screw 17 and is pivotally connected to the other end of the intermediate lever 18. Move the yarn holding intermediate link 19 in the direction of the arrow.

The functions of these levers 6.18 and links 14 serve to expand the amount of linear movement to the amount of movement necessary for thread retention, and the return spring 34 moves the pin screw 12 around the outer periphery of the thread holding cam 4. It acts as a constant force.

A thread holding adjustment link 21 is coupled to the other end of the thread holding intermediate link 19 by a set screw 20, and a thread holding lever 22 is pivotally attached to the other end of the link 21 by a set screw 36. The thread holding lever 22 is attached to the feeder collecting plate 3 by a set screw 40.
3, and a movable yarn holding plate 28 is pivotally attached to the other end. Reference numeral 29 denotes a fixed yarn holding plate that is provided overlappingly on the upper surface of the movable yarn holding plate 28, and the tips 28a and 29a of both
are set up opposite each other. Further, the fixed thread holding plate 29 is held on the feeder collecting plate 33 by a thread holding plate support 30. Further, 31 is a feed plate, 32 is a screw on the feed collection plate, 23 is a set screw for the throat plate 27, 24 is a feed plate washer, 25 is a screw on the feed plate,
26 is a feed plate.

Now, the thread holding intermediate link 19 and the thread holding adjustment link 21 connected to the thread holding intermediate lever 18 are connected to the movable thread holding plate 2.
The attachment of 8 adjusts the position and transmits movement to the thread holding lever 22. The thread holding lever 22 reverses the linear motion, and a groove 41 is formed on the back surface of the feed plate 26 so that the hook portion of the tip 28a of the movable thread holding plate 28 is attached to the needle drop portion.
is provided, and this portion serves as a guide for the movable yarn holding plate 28.

Here, even if the feed plate 26 moves left and right and back and forth during one cycle, the movable thread holding plate 28 moves in the direction of the dotted line arrow in FIG. The thread is held by the tip 29a of the fixed thread holding plate 29 for a predetermined period of time so that it does not come off.

When the sewing machine starts and reaches the end of the fourth stitch, the projection 4a of the thread holding cam 4 has passed through the pin screw 12 of the thread holding cam lever 6, and the tension of the return spring 34 causes the thread holding link 14 to move between the Via lever 18 11
1, and the movable yarn holding plate 28 moves in the opposite direction to the dotted arrow via the intermediate link 19, adjustment link 21, and yarn holding lever 22, and its tip 28a and The thread held between the fixed thread holding plate 29 and the tip 29a is released.

〔Effect of the invention〕

Conventionally, the end of the thread at the beginning of sewing must be held with a presser foot, etc. until the first stitch is formed, and if there is no presser foot, etc. that has this function, the thread of the thread forming the stitch will be If tension was not applied to the ends and the threads were not tightened, the threads would become dango-shaped and the seams could not be normally obtained.

The present invention is constructed as described above and has the function of a presser foot, so that the thread does not become lumpy and can be sewn without a presser foot. In addition, conventionally, when installing these mechanisms, it was normal to install them on the bottom surface of the throat plate and near the hook, but since the present invention can be installed on the top surface of the throat plate, it is not necessary to remove them from the needle hole on the top surface of the throat plate. In order to catch the thread that comes out and hold it until the specified time while maintaining a constant gap between the thread and the back of the sewing material,
Is the length of the thread that appears on the back of the fabric as short as possible (can be set).

In addition, if the thread end remains on the top surface of the button at the beginning of sewing as in the conventional sewing machine, it is necessary to cut and remove the remaining thread in post-processing or shorten the thread length of the needle thread at the beginning of sewing. If the thread length of the needle thread is shortened (then there will be insufficient supply of thread to the hook part necessary for stitch formation, making sewing impossible.

In the present invention, the first stitch is not configured, and the short thread end catches and holds the thread in the second stitch where it passes from the hook to the upper surface of the throat plate. Therefore, the thread end of one stitch S is always You can make it come to the wrong side of the fabric.

[Brief explanation of drawings]

FIG. 1 is a plan view of a thread holding mechanism showing an embodiment of the present invention, and FIG. 2 is a side view of the same. Explanation of main parts of the figure 4...Thread holding cam 4a...Protrusion 6...Thread holding cam lever 12...Pin 14.19.21...
・Link 18.22...Reno Jin (link mechanism)
27... Throat plate 28... Movable thread holding plate 29...
Fixed thread holding plate 34...-Return knob 35...Feed cam shaft

Claims (1)

[Claims] A feed cam shaft that rotates once per cycle of a cycle sewing machine, a thread holding cam fixed to the cam shaft and having a protrusion on its outer circumferential surface, and a pin at one end that is constantly pressed against the outer circumferential surface of the thread holding cam. , a thread holding cam lever rotatable about a fulcrum, a movable thread holding plate provided on the needle plate so that its tip is located at the needle drop point, and a thread holding cam lever disposed between the movable thread holding plate and the thread holding cam lever. , a link mechanism that reciprocates the movable yarn holding plate by the rotational movement of the cam lever, a tip portion that is opposite to the tip of the movable yarn holding plate and can hold the yarn, and a link mechanism that is stacked on the upper surface of the movable yarn holding plate. and a fixed thread holding plate provided with a fixed thread holding plate, and while the pin of the thread holding cam lever is positioned on the protrusion of the thread holding cam, the thread is held at the tip of the both thread holding plates, and the pin of the thread holding cam lever is Thread holding in a cycle sewing machine, characterized in that the length of the circumferential surface of the protrusion is set so that the length of time that the cam rests on the protrusion of the thread holding cam is from the beginning of the second stitch to the end of the fourth stitch. mechanism.