JP2904539B2 - Sewing machine balance mechanism - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a balance mechanism of a sewing machine, and more particularly to a sewing machine having a balance mechanism capable of easily threading.

(Problems to be Solved by the Prior Art and the Invention) The upper thread path from the thread top, which is the upper thread supply source of the conventional lockstitch sewing machine, to the needle hole of the sewing machine needle is disposed above the sewing machine frame. A thread guide, a thread tensioner including a thread tensioner and a thread take-up spring disposed below the thread tensioner, and a known balance that moves up and down above the thread tension are arranged.

The balance rises to lift and absorb the upper thread released by the needle thread catching means when the needle is raised, and the thread hook between the balance and the thread tensioner is absorbed by the elevation of the balance. It is arranged below the balance and the thread tensioner for effective operation.

Therefore, when a new thread is threaded on the upper thread path, the upper thread pulled out from the thread spool and passing through the thread guide and thread tensioner above the sewing machine frame is temporarily threaded on the lower thread thread, Next, the thread is threaded into the thread hole of the lower needle after the thread is threaded through the thread hole of the upper balance by operating again upward, and especially for a beginner, the operation is complicated and it is difficult to thread accurately. there were.

For this reason, the operation may be performed without performing the threading operation on the lower side or the threading operation on the upper balance, and a phenomenon that the seam may not be formed correctly may occur.

As an apparatus for facilitating thread hooking, the present applicant has previously disclosed in Japanese Patent Application Laid-Open No. 63-229090 an automatic thread hooking apparatus in which thread hooking is performed by a balance operated by starting a sewing machine. In order to achieve automatic threading, a balance drive mechanism different from the conventional one is required, and since the operating direction of the balance is different from the rising direction of the needle, as a result, the thread supply amount on the balance is completely different from the conventional one. They are not the same.

Therefore, it is necessary to adjust the sewing differently from the conventional one.Furthermore, the bent thread path caused by the difference between the pull-up direction at the time of pulling the upper thread and the absorbing operation direction of the balance causes an increase in the thread resistance at the time of absorbing the upper thread. On the other hand, the finished state of the yarn path had to be kept better than before.

SUMMARY OF THE INVENTION It is an object of the present invention to solve these problems and to provide a sewing machine provided with a balance mechanism which can obtain a thread supply amount on a balance which is almost the same as that of the related art and has a small thread resistance and easy threading.

(Means for Solving the Problems) For this reason, in the present invention, a balance crank 7 that rotates together with the drive shaft 2 and a position on the balance crank that is rotatable to a predetermined amount of eccentric position from the rotation axis. And a balance main body movable between a bottom dead center position, which is a maximum yarn relaxation position, and a top dead center position, which is a maximum yarn take-up position, and yarn supply before and after the maximum yarn relaxation position of the balance main body. A thread holding portion provided on the balance body so as to intersect with the thread supply path from the source to the needle 17 and having a thread introduction opening opened outward for introducing a sewing thread, parallel to the rotation axis of the balance crank 7; A balance support rotatably supported around a fixed axis on the sewing machine frame 1 and a free end rotatably connected to an intermediate portion of the balance main body. Below the drive shaft 2 The direction from the point where the thread holding portion is located at the top dead center position to the point where the thread holding portion is located at the bottom dead center position, and the rotation axis of the balance crank 7 at the top dead center position and the fixed axis. The fixed axis is arranged so that the direction extending in the same direction is substantially the same.

Thereby, the thread guide disposed above the sewing machine frame between the upper thread supply source and the needle, and the thread path disposed above the sewing machine frame between the thread guide and the needle, are provided. The balance arranged between the yarn path and the yarn guide moves up and down in synchronization with the up and down movement of the needle, and the tip is different from the conventional one and moves in the opposite direction to the worker when descending from above. When the robot reaches the lower position, it moves toward the operator when ascending from below, and forms a motion trajectory reaching the upper position.

Therefore, the upper thread pulled out from the upper thread supply source is hooked on the thread guide and the thread path arranged at the upper part of the sewing machine frame, and is threaded through the thread hole of the needle. Sometimes the sewing machine motor is started by the start signal of the start / stop means, which is above the yarn guide and the yarn path, and the opening at the tip of the sewing machine rises above the bottom dead center between the yarn guide and the yarn path. The thread is automatically caught and performs the same balance function as before.

Further, for the insufficient upper thread of the first stitch before the opening catches the upper thread, the upper thread detecting means detects the tension state of the upper thread between the thread guide and the needle and detects the amount of the insufficient thread. Is supplied by a needle thread supply device.

(Example) Next, an example of the present invention will be described in detail with reference to the drawings.

FIG. 2 is an explanatory view of the mechanism of the sewing machine according to the present invention. Reference numeral 4 denotes a pattern selection means for selecting a desired pattern by operating a pattern selection key 5 provided with a pattern display.

 The selected pattern is displayed on the pattern display means 6.

A drive shaft 2 connected to a drive source (not shown) and transmitting rotation is supported on the sewing machine frame 1 so as to be rotatable in the direction of arrow A, and a needle bar 3 connected to the drive shaft is connected to the sewing machine. It is supported on the machine frame 1 so as to be able to move up and down.

 A needle 17 is fixed to the tip of the needle bar 3.

A needle bar crank 8 is fixed to one end of a balance crank 7 provided at the shaft end of the drive shaft 2, and one end of a crank rod 9 is rotatably fitted to a shaft portion of the needle bar crank.

The other end of the crank rod is a needle bar holder through which the needle bar 3 is inserted.
It is rotatably fitted to the shaft of 10 and the needle bar 3 holds the needle bar
The needle bar support 11 is vertically movably inserted above and below the needle bar support 11.

The needle bar support is fitted on a shaft 12 fixed to the machine frame 1,
The vertical movement is restricted, and it is supported so that it can move only in the rotation direction.

One end of a connecting rod 13 is connected to a side of the needle bar support 11 opposite to the needle bar 3, and the other end of the connecting rod is connected to an output shaft of a needle bar amplitude stepping motor 14 fixed to the sewing machine frame 1. It is connected to the fixed arm via a link.

A needle plate 18 having a needle hole through which a fixed needle 17 is inserted is fixed to the end of the needle bar 3 on the sewing machine frame 1 below the needle bar 3.

Reference numeral 19 denotes a feed dog, which moves in and out of a feed dog groove provided in the needle plate 18 and cooperates with the cloth presser 20 to move the cloth held therebetween in synchronization with the vertical movement of the needle 17.

Reference numeral 21 denotes a shuttle which serves as a needle thread supplementary means. The shuttle is rotatably supported by the sewing machine frame 1 below the needle plate 18, and is connected to the drive shaft 2 and rotates in synchronization with the vertical movement of the needle 17. 22 fixed gear
Rotation is transmitted by meshing a gear 23 of the hook integrally fixed to the lower part of the hook 21 and the hook 21.

A balance 15 moves up and down in synchronization with the up and down movement of the needle.
The drive mechanism of the balance will be described with reference to FIG.

A balance support 16 has one end rotatably fitted on a balance support shaft 25 fixed to the sewing machine frame 1.

Reference numeral 26 denotes a balance crank pin, which is fixed to the balance crank 7 at a predetermined distance l from the axis of the drive shaft 2 in the radial direction, and one end of the balance 15 is rotatably fitted to the balance crank pin. I am wearing it.

A pin 30 is fixed to an intermediate portion of the balance, and the other end of the balance support 16 is rotatably fitted to the pin.

The tip of the balance 15 is as shown in FIGS. 1 and 3, and has an opening 15a having an upper opening capable of catching the upper thread 31 when ascending from below, and a guide section for guiding the thread to the opening. 15b
And a thread hole 15c for holding the captured upper thread following the opening.

In the configuration of the above-described balance driving mechanism, the arrangement position of the balance support shaft 25 parallel to the drive shaft 2 is different from the conventional one, and is disposed below the drive shaft 2 by a predetermined distance. The configuration of each part is the same as the conventional one.

FIG. 4 shows the movement trajectory of the thread hole 15c at the tip of the balance 15 having this configuration.

The figure is viewed from the direction of arrow D in FIG. 1, moves in the direction of arrow B in FIG. 4, and is almost at point a at the needle bar top dead center, which is the uppermost position of the needle 17, and is further driven. Balance with rotating shaft
The point b at which the fifteen thread holes 15c have moved to the uppermost position is the top dead center of the balance, and the lowest point c is the bottom dead center of the balance.

The drive shaft rotation angle at which the top dead center of the balance and the top dead center of the needle bar at the bottom dead center of the balance are 0 degrees is the same as before, but the operating range of the balance is lower than that of the prior art (FIG. 5). different. That is,
In a movement trajectory in which the balance main body 15 moves between its top dead center and bottom dead center in conjunction with the rotation of the sewing machine drive shaft 2, the thread holding portion 15c moves from the top dead center to the bottom dead center. In the trajectory to move to, from the vicinity of approximately the middle of the trajectory, to the maximum distance in the direction progressively away from the user in the front direction, then move toward the user as approaching the bottom dead center, from the bottom dead center In the movement trajectory in the direction of the top dead center, the robot gradually moves toward the user from the bottom dead center to the substantially middle portion, and then gradually moves toward the top dead center in the direction away from the user.

Next, the thread guide and thread path of the upper thread will be described with reference to FIGS. 6 and 7. FIG.

32 is a known thread tensioner which also serves as a thread guide,
The upper thread from the thread top 33 on which the 31 is wound is applied to the upper thread sandwiched between the pair of thread tension discs 34 and 35 so as to apply a thread tension to the upper thread.
It is arranged on the upper part of the sewing machine frame 1.

Reference numeral 36 denotes a thread guide cover, which is disposed between the thread tensioner 32 and the balance 15 and is fixed to the sewing machine frame 1 to form an open portion 36a for guiding the upper thread downward. .

A guide wall 1a for threading the upper thread from the thread tensioner 32 is formed at a position facing the open portion 36a of the sewing machine frame 1, and a lower end of the guide wall is provided at the lower end as shown in FIG. A guide portion 1b for guiding the thread hook is formed.

Reference numeral 37 denotes a thread hook pin, which is mounted at a position facing the open portion 36a below the thread guide cover 36.

The upper thread guide position connecting the thread hook pin and the guide portion 1b is located at the opening 15a at the tip of the dead center position c at the bottom in FIG.
The opening 15a is set to a position that is higher than the upper position and can be captured by the opening 15a when the balance is raised, for example, FIG. 4P.

A space 1d for the balance 15 to move up and down is formed between the rear wall 1c of the sewing machine frame 1 and the guide portion 1b between the thread hook pin 37 and the guide wall 1a.

Next, the threading action of the sewing machine of the present invention and the operation of the balance will be described.

When the sewing machine stops, the needle bar is stopped at the needle bar top dead center position, and the balance is at the upper position a as shown in FIG.

When the presser lifter (not shown) is operated at the time of thread hooking, the clamping pressure between the pair of thread tension plates 34 and 35 of the thread tensioner 32 is released, and the upper thread 31 pulled out from the thread top 33 becomes a pair. Is threaded on the thread tension plate.

Next, the guide is guided between the guide wall 1a of the sewing machine frame 1 and the thread guide cover 36, guided to the guide section 1b, and the release section 36 of the thread guide cover 36 is provided.
The thread is threaded on the threading pin 37 from underneath a and threaded through the threaded hole of the needle 17.

Next, following the lifting operation, the drive shaft 2 is rotated by the operation of the sewing machine starting means (not shown).
The thread holding portion (the thread hole 15c) at the end of the line (a) is a trail behind the top dead center as shown by the arrow in the figure, and descends to the bottom dead center position c.

Next, it rises as a trajectory on the near side. At this time, the upper thread 31 hooked by the thread is guided by the guide portion 15b at the tip of the balance 15, enters the thread hole 15c through the opening 15a, is guided and held, and the balance 15 captures the upper thread.

It should be noted that the thread holding portion (the thread hole 15c) and the opening 15a of the balance 15 are formed as shown in FIG.
It may be.

In order to guide the upper thread 31 into the space 1d of the sewing machine frame 1, the outer shape of the guide portion 101b following the guide wall 101a is changed from the guide wall 101a toward the thread hook pin 137 as shown in FIG. The guide outer shape 101e having the inclined surface may be formed to facilitate the threading of the upper thread 31 on the open portion 36a below the thread guide cover 36.

(Effects of the Invention) As described above, according to the present invention, a thread guide disposed above a sewing machine frame between a needle thread supply source and a needle, and a sewing machine frame formed between the thread guide and the needle. And a yarn path arranged between the yarn path and the yarn guide to form an opening below, and move to the operator side to reach the upper position at least when ascending from below. A balance for forming a trajectory, wherein when the balance is raised, the upper thread is absorbed by moving upward toward the yarn guide and the yarn path, and the upper thread is supplied by moving downward. By having been configured to have a mechanism, the upper thread thread hook for sewing preparation work is
If the upper thread pulled out from the upper thread supply source is threaded through the needle after threading on the thread guide and the threading pin mounted on the sewing machine frame, by starting the sewing machine, the above-described operation is automatically performed when the balance is lifted. Since the upper thread between the thread guide and the thread catching pin can be captured and the balance action can be performed, it is possible to simplify and facilitate the thread catching work for the thread catches that are arranged in a complicated vertical position as in the past. I can do it.

The balance of this device is different from the conventional one only in the front and rear positions and the height position when the balance is operated, and the upper and lower phases and the supply amount of the thread on the balance are almost the same as the conventional one. Adjustment is possible, and it is possible to replace the conventional balance for execution. Also, the operator can thread the upper balance by the same method as in the related art.

Further, the movement position of the balance can be made extremely lower than before, and the upper position of the sewing machine frame can be lowered to make the sewing machine compact.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a drive mechanism of a balance of the present invention, FIG. 2 is an explanatory view of a mechanism of a sewing machine, FIG. 3 is an explanatory view of a tip shape of the balance,
FIG. 4 is an explanatory view of the movement locus of the balance of the present invention, FIG. 5 is an explanatory view of the movement locus of the conventional balance of the sewing machine, FIG. 6 is an explanatory view of each part of the threading mechanism, and FIG. Explanatory drawing of part, eighth
FIG. 9 is an explanatory view of another embodiment of the opening portion of the balance tip, FIG. 9 is an explanatory view of another embodiment of the upper thread guide section, 2 is a drive shaft,
7 is a balance crank, 15 is a balance main body, 17 is a needle, 15c is a thread hole as a thread holding part, 16 is a balance support, and 25 is a balance support shaft having a fixed axis.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-215495 (JP, A) JP-B-28-4287 (JP, B1) Jiko-49-20753 (JP, Y1) (58) Field (Int.Cl. ⁶ , DB name) D05B 49/00-49/06

Claims (1)

(57) [Claims] 1. A balance crank (7) mounted on a sewing machine drive shaft (2) and rotating together with the sewing machine drive shaft, and one end rotatable at a predetermined radial distance from the rotation center of the balance crank. The balance support (1
A balance main body (15) rotatably connected to one end of 6) and having a thread holding portion (15c) open to information for introducing a sewing thread at a free end thereof; A balance support shaft (25) whose other end is parallel to the sewing machine drive shaft (2)
And a thread tensioner disposed on one side of the balance main body (15) and between the upper thread supply source and the balance main body (15). (32), an upper thread path including a thread tension member (37) disposed between the thread tensioner and the balance body (15), and the balance body (15).
On the other side of the needle (1) attached to the lower end of the needle bar (3)
7), the balance support shaft (2
5) is located at a predetermined distance below the position of the sewing machine drive shaft (2), and the free end of the balance main body (15) is dead dead in conjunction with the rotation of the sewing machine drive shaft (2). In the movement trajectory moving between the point and the bottom dead center, in the trajectory in which the thread holding portion (15c) moves from the top dead center to the bottom dead center, At the maximum distance in the direction of gradually moving away from the user, and then moves in the direction of the user as approaching the bottom dead center, in the movement trajectory from the bottom dead center to the top dead center,
From the bottom dead center to the substantially middle part, it gradually moves in the direction of the user, and then gradually moves to the top dead center in the direction away from the user. A balance mechanism located above a position of a bottom dead center of a free end of the sewing machine.