JP2568039Y2 - Thread trimming control device for cycle sewing machine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread trimming control device for a cycle sewing machine which repeats a predetermined sewing operation every cycle.

[0002]

2. Description of the Related Art In general, a cycle sewing machine for performing sewing such as bar tacking is known. In this cycle sewing machine, after one cycle of sewing operation is completed, a thread trimming operation is performed at a timing corresponding to the last needle. The thread trimming mechanism that performs thread trimming cuts the upper and lower threads connected to the needle and the shuttle from the workpiece by reciprocating the movable blade.
For example, in the thread trimming control device described in Japanese Patent Publication No. 62-622, the thread trimming timing is determined by the interlocking of the cut-off frame, and the thread trimming cam arm is pressed against the cam surface of the thread trimming cam fixed to the main shaft. By swinging, a predetermined operation is transmitted to the thread cutting mechanism, and a thread loosening operation and a thread cutting operation are performed.

In such a conventional cycle sewing machine, a general-purpose motor is usually employed as a drive source of a main shaft, and accordingly, a device for increasing / decreasing a sewing speed and a clutch for transmitting or interrupting a driving force are used. A mechanism and the above-mentioned shutoff frame are provided. As described above, the thread cutting device is configured to interlock with the blocking frame.

[0004]

However, in such a conventional cycle sewing machine provided with a thread trimming device linked to a cut-off frame, the structure is complicated, the number of parts is increased, and a large force is applied to the cam of the cut-off frame. It is loaded and has a problem in durability.

In order to solve this problem, it has been considered that a servomotor or an electric motor whose rotation state is electrically controlled is used to omit the accelerating / decelerating device and the cutoff frame. The problem is how to control the above-described thread cutting.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thread trimming control device for a cycle sewing machine which is capable of performing good thread trimming control over a long period of time with a simple configuration.

[0007]

In order to achieve the above object, the present invention drives a main shaft to rotate by using a drive motor whose rotation state is electrically controlled, and performs a predetermined sewing operation every cycle. In a thread trimming control device of a cycle sewing machine having a thread trimming mechanism for performing a thread trimming operation of a sewing thread by reciprocating a movable blade, a reciprocating operation is performed on a cam surface of a thread trimming cam fixed to the main shaft. A thread trimming cam arm which is oscillated by pressing and transmits a predetermined thread trimming operation to the thread trimming mechanism; a thread trimming control cam which rotates one time during one cycle of sewing operation in conjunction with the main shaft; A thread trimming control lever which is pressed against the cam surface of the thread trimming control cam and swings; A thread trimming control arm for contacting and separating The it has.

[0008]

In the apparatus having the above-mentioned structure, the thread trimming control lever is pressed against the cam non-formed surface of the thread trimming control cam during the one-cycle sewing operation. The thread trimming control arm is maintained at a position where the thread trimming cam arm is separated from the cam surface of the cam. Then, at the timing corresponding to the last stitch of the sewing operation of one cycle, the thread trimming control lever moves onto the cam forming surface of the thread trimming control cam, thereby causing the thread trimming cam arm to move onto the cam surface of the thread trimming cam. The thread trimming control arm is moved to a position where the thread trimming contact is made, and the thread trimming operation is performed by performing a predetermined swing operation of the thread trimming cam arm based on the thread trimming cam.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. In the thread cutting control device of the cycle sewing machine in the embodiment shown in FIGS. 1 and 2, the main shaft 2 is arranged so as to extend substantially horizontally above the sewing machine. A drive pulley 1 is screwed and fixed to an end of the main shaft 2 so as to rotate integrally therewith, and a drive motor 4 is disposed directly below the drive pulley 1. The drive motor 4 includes a servomotor or an electromotor whose rotation state is electrically controlled, and the like.
Stop control is performed by a fixed number of stitches or a detection signal from a sensor. A transmission belt 5 such as a V-belt is stretched between the output shaft of the drive motor 4 and the drive pulley 1.

A thread cutting cam 6 formed in a predetermined outer peripheral shape is fixedly screwed to the main shaft 2, and a thread cutting cam arm 8 is provided near the thread cutting cam 6 with the main shaft 2. It is provided so as to be swingable about a substantially parallel axis.
Rollers 10, 12 are rotatably mounted on both ends of the thread cutting cam arm 8.
Are disposed on the cam surface of the thread cutting cam 6 at positions where they can be pressed against the cam surface. On an outer peripheral surface of the thread cutting cam 6, a cam surface for giving a predetermined thread cutting operation to the thread cutting cam arm 8 is formed. The roller 12 on the other side of the thread trimming cam arm 8 comes into contact with and separates from a limiting plate 32 that is linked to a push-up mechanism described later. This will be described later.

An upper end of a thread cutting connecting rod 11 is rotatably connected to an end of the thread cutting cam arm 8 on a side where the roller 12 is provided. The thread cutting connection rod 11 extends downward and has a lower end rotatably connected to a substantially L-shaped thread cutting link 13. The thread cutting link 13 is fixed to an intermediate portion of a shaft 17 rotatably supported by the arm machine frame so as to extend in a direction orthogonal to the main shaft 2. A tension spring 25 for applying a biasing force in a direction to push the thread cutting connection rod 11 upward is connected to the other end, and a thread cutting mechanism extending toward a thread cutting mechanism (not shown) is provided at the other end. The connecting rod 16 is rotatably connected. Therefore, the thread trimming cam 6 and the thread trimming cam arm 8 described above are provided.
The thread cutting operation transmitted through the thread cutting connection rod 11 and the thread cutting link 13 are transmitted to the thread cutting mechanism.

A thread trimming control arm 18 is screwed and fixed to a portion of the shaft 17 in the axial direction so as to extend downward in the figure, and swings integrally with the rotation of the shaft 17. It is supposed to be. The swinging end portion of the thread trimming control arm 18 at the lower end in the figure is configured to engage / separate with the swinging end of a thread trimming control lever 20 pivotally supported in a horizontal direction.

One end of the thread trimming control lever 20 which is formed in a substantially L-shape in plan view engages with and separates from the thread trimming control arm 20 as described above.
Rollers 22 are provided on the multi-end side of the zero. A tension spring 2 is provided at the end of the thread trimming control arm 20 on the roller 22 side.
The roller 22 is pressed against the outer peripheral surface of the thread trimming control cam 23 by the urging force of the tension spring 26.

The thread trimming control cam 23 is supported substantially horizontally, and its rotary shaft 24 extends upward toward the main shaft 2 side. The main shaft is connected via a worm gear or the like (not shown). 2 are connected. Then, one rotation is performed during one cycle of the sewing operation in conjunction with the main shaft 2. On a part of the outer peripheral surface of the thread cutting control cam 23, a cam forming surface 23b is formed so as to form a concave groove. As described below,
When the roller 22 of the thread cutting control lever 20 is dropped into the cam forming surface 23b, the roller 10 of the thread cutting cam arm 8 is pressed against the outer peripheral surface of the thread cutting cam 6 and the thread cutting is performed. When the roller 22 of the control lever 20 is maintained on the cam non-forming surface 23a of the thread cutting control cam 23, the roller 10 of the thread cutting cam arm 8 is separated from the thread cutting cam 6 side.

One end of a push-up connecting rod 31 extending from a push-up mechanism (not shown) is connected to one end of a push-up link 33 which is pivotally supported. The push-up link 33 is formed in an L-shape, and the lower end of the upper and lower rod 34 is connected to the other end. The upper and lower rods 34 extend upward in a twisted manner, and the upper ends thereof are pressed against one side of the above-described limiting plate 32. The limiting plate 32 is formed of a substantially fan-shaped cam, and is rotatably supported on an axis substantially parallel to the main shaft 2. A step is formed on a cam surface provided on an outer peripheral portion of the limiting plate 32, and the step is configured to be engaged with the roller 12 of the thread cutting cam arm 8.

When the cloth presser is held up by the lifting mechanism, the upper and lower rods 34 are lowered by the lowering of the lifting link 33 to push the limiting plate 32 downward, and the step portion of the limiting plate 32 is Roller 12 provided on cutting cam arm 8
Engaging upward, the roller 10 of the thread trimming cam arm 8 separates from the thread trimming cam 6. Therefore, thread trimming does not operate.
On the other hand, when the presser foot lowers the work clamp, the upper and lower rods 34 move up. As a result, the restricting plate 32 tries to rotate clockwise by the tension spring 35, but the roller 12 is engaged with the outer peripheral cam portion of the restricting plate 32 by the urging force of the tension spring 25. Therefore, the restricting plate 32 does not rotate and maintains the state. Thereafter, when sewing is started, the thread trimming control cam 23 rotates, and the roller 22 of the control lever 20 rides on the cam 23a of the thread trimming control cam 23. Then lever 2
1 pushes the arm 18 to rotate the shaft 17, rotates the link 13 downward through the spring 25, and pushes down the rod 11. As a result, the engagement between the limiting plate 32 and the roller 12 is released, and the limiting plate 32 rotates upward by the urging force of the tension spring 35. When the restriction plate 32 and the roller 12 are separated from each other, the rod 11 can be raised, and the shaft 17 rotates to try to operate the thread cutting mechanism. However, as described above, while the roller 22 of the thread trimming control lever 20 is on the cam 23a of the thread trimming control cam 23, that is, during sewing, the lever 20 pushes the arm 18 to rotate the shaft 17, and the spring 2
The link 11 is rotated via 5 to push down the rod 11. Thus, the lever 20 acts on the thread cutting arm 8 so that the roller 10 thereof is separated from the thread cutting cam 6. Therefore, the thread cutting mechanism does not operate until the roller 22 enters the cam forming surface 23b of the cam 23. For this reason, malfunction of the thread trimming mechanism during sewing can be prevented.

In this embodiment, the roller 22 of the thread trimming control lever 20 comes into pressure contact with the cam non-forming surface 23a of the thread trimming control cam 23 while the sewing operation of one cycle is being performed. I have. As a result, the other end of the thread trimming control lever 20 is maintained at a position where the thread trimming control lever 20 is advanced forward as shown in FIG. The swing of the turning control arm 18 is locked. As a result, the roller 1 of the thread trimming cam arm 8
0 is held at a position slightly away from the cam surface of the thread cutting cam 6, and the thread cutting operation is not performed.

Next, when the timing corresponding to the last needle of one cycle of sewing operation comes, the thread trimming control lever 20 is turned on.
The roller 22 falls into the cam forming surface 23b of the thread trimming control cam 23 as shown in FIG. As a result, the other end of the thread trimming control lever 20 is moved to a position retracted rearward in the drawing, and the thread trimming control arm 18 locked to the other end of the thread trimming control lever 20 swings rearward. Be moved.
As a result, the roller 10 of the thread cutting cam arm 8 is pressed against the cam surface of the thread cutting cam 6, and the thread cutting cam arm 8 performs a predetermined swing operation based on the thread cutting cam 6. This swinging operation is transmitted to the thread cutting mechanism as a thread cutting operation by the thread cutting connecting rod 11 and the thread cutting link 13, and a predetermined thread cutting operation is performed by the thread cutting mechanism.

[0019]

As described above, the thread trimming control device of the cycle sewing machine according to the present invention presses the thread trimming control lever on the cam non-forming surface of the thread trimming control cam during the sewing operation of one cycle. The thread trimming cam arm is moved away from the cam surface of the thread trimming cam, and the thread trimming control lever is moved to the cam forming surface of the thread trimming control cam at the timing corresponding to the last stitch of the sewing operation in one cycle. Then, the thread trimming cam arm is brought into contact with the cam surface of the thread trimming cam so that a predetermined thread trimming operation is performed. With the configuration, thread trimming control can be performed well for a long time,
The reliability of the cycle sewing machine can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a main part of an internal structure of a cycle sewing machine according to an embodiment of the present invention.

FIG. 2 is an explanatory side view of the structure shown in FIG. 1;

FIG. 3 is a partially enlarged perspective explanatory view showing a cam operation of the structure shown in FIG. 1;

[Explanation of symbols]

 2 Main shaft 4 Drive motor 6 Thread trimming cam 13 Thread trimming link 18 Thread trimming control arm 20 Thread trimming control lever 23 Thread trimming control cam

Claims (1)

(57) [Scope of request for utility model registration] 1. A main shaft is rotationally driven by using a drive motor whose rotation state is electrically controlled, and a predetermined sewing operation is repeated every cycle. The movable blade is reciprocated. In a thread trimming control device of a cycle sewing machine having a thread trimming mechanism for performing a thread trimming operation, a thread trimming cam fixed to the main shaft is swung by being pressed against a cam surface of the thread trimming cam, A thread trimming cam arm that transmits a predetermined thread trimming operation to a mechanism; a thread trimming control cam that rotates in conjunction with the main shaft; a thread trimming that is swung by being pressed against a cam surface of the thread trimming control cam. A control lever, and a thread trimming control arm that engages with and separates from the swing side of the thread trimming control lever and causes the thread trimming cam arm to contact and separate from the cam surface of the thread trimming cam. Characteristic thread trimming control device for cycle sewing machines.