JP3824923B2 - 2-needle sewing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thread trimmer for a two-needle sewing machine.
[0002]
[Prior art]
As a conventional example of a thread cutting device for a sewing machine, what is disclosed in Japanese Patent Publication No. 1-53078 will be described with reference to FIGS. A hook shaft base 8 to which a hook and a thread trimming device (not shown) are attached is fixed to a sewing machine bed (not shown) of the sewing machine. The operating body 19 transmits the displacement of the thread trimming cam 20 fixed to the lower shaft 32 to a moving knife (not shown) for cutting the upper and lower threads via the swing arm 18 to cut the upper and lower threads. A support 21 fixed to the sewing machine bed supports the guide shaft 22. A cam follower arm 23 is inserted into the guide shaft 22 so as to be slidable on the guide. The cam follower arm 23 has a roller 24 formed so as to be detachable from the thread trimming cam 20. The spring 25 is for separating the roller 24 from the thread trimming cam groove 26 after the thread trimming is completed.
[0003]
The rotary solenoid 27 attached to the support 21 rotates in response to the thread trimming signal and transmits the rotation to a swing lever 28 fixed to the shaft of the rotary solenoid 27. At the tip of the swing lever 28, there is a roller 30 that is slidably engaged with the concave groove 29 of the cam follower arm 23. Further, the thread trimming cam 20 has a thread trimming cam groove 26 for reciprocating the moving knife on the outer periphery, and always rotates during the sewing machine operation. The cam follower arm 23 and the operating body 19 are connected by a universal joint 33 using two spherical bearings.
[0004]
The operation of this conventional example will be explained. When a pedal provided at the lower portion of the table (not shown) is operated to stop the operation of the sewing machine, a signal is transmitted to the control circuit of the needle fixed position stop motor, and the needle bar The sewing machine stops operating when is near the lowest point.
[0005]
Next, when the pedal is operated to perform automatic thread trimming, the sewing machine that has received the thread trimming signal starts rotating at a low speed. At the same time, the rotary solenoid 27 receiving the thread trimming signal rotates and pushes down the cam follower arm 23 via the swing lever 28 and the roller 30. The roller 24 supported by the cam follower arm 23 engages with the thread trimming cam groove 26, moves along the cam phase, swings the cam follower arm 23, and interlocks the operating body 19 via the universal joint 33. To do. The swing arm 18 fixed to the operating body 19 swings, and the moving knife moves further through the swing arm 18 to cut the upper and lower threads.
[0006]
8 and 9 show a conventional thread trimming device for a sewing machine.
The thread trimming device has substantially the same structure as that shown in FIGS. 6 and 7, but a thread loosening cam 31 is fixed to the lower shaft 32 in addition to the thread trimming cam 20. The thread loosening cam 31 is formed with a convex cam body 31a. Further, one end of the thread loosening lever 34 is rotatably attached by a step screw 34a. The thread releasing lever 34 is provided with a roller 35 that engages with the convex cam body 31a of the thread releasing cam 31 at the center thereof, and one end of a wire 36 is fixed to the tip thereof. The other end of the wire 36 is connected to a pair of tension plates (not shown) that sandwich the upper thread.
[0007]
When the pedal is operated to perform automatic thread trimming, the rotary solenoid 27 that has received the thread trimming signal rotates to cut the upper and lower threads as described above. In this conventional example, before the upper and lower threads are cut. Further, the roller 35 of the thread releasing lever 34 is engaged with the convex cam body 31 a of the thread releasing cam 31. Then, the thread loosening lever 34 rotates in the clockwise direction in FIG. 8 along the shape of the convex cam body 31 a, so that the wire 36 fixed to the tip of the thread loosening lever 34 follows the rotation of the lower shaft 32. The pair of tension plates pulled in the direction of arrow C and connected to the wire 36 loosen the tension of the upper thread that has been clamped.
[0008]
[Problems to be solved by the invention]
In the above two conventional techniques, the cam follower arm 23 is moved up and down by the rotary solenoid 27. Thus, two spherical bearings are used to absorb this vertical motion, but this spherical bearing is expensive.
[0009]
8 and 9, when the thread trimming cam 20 and the thread loosening cam 31 are fixed to the lower shaft 32, the thread trimming mechanism including the cam follower arm 23, the universal joint 33, etc. In terms of its function, the thread loosening mechanism extending from the thread trimming cam 20 in the direction of the hook shaft base 8 and comprising the thread loosening lever 34, the wire 36, etc. It extends across the opposite direction. However, in the conventional example, the thread loosening cam 31 is arranged in the direction of the shuttle shaft base 8 rather than the thread trimming cam 20. For this reason, the thread trimming mechanism and the thread loosening mechanism are arranged so as to intersect with each other, and it is necessary to avoid the interference of the movable parts, and the structure becomes complicated and difficult to assemble.
[0010]
Accordingly, an object of the present invention is to provide a thread trimming device for a two-needle sewing machine that can absorb the vertical movement of a cam follower arm without using an expensive spherical bearing.
[0011]
Another object of the present invention is to provide a thread trimming device for a two-needle sewing machine that can be easily assembled by arranging the thread trimming mechanism and the thread loosening mechanism so as not to intersect.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention,
Two needles that reciprocate in conjunction with the spindle,
Two hooks that cooperate with this needle to form a seam;
Two moving knives provided in the vicinity of each hook to cut the upper and lower threads by movement;
A thread trimming cam fixed to the lower shaft;
A first connecting member having one end side connected to the moving knife through a link mechanism and having an engagement hole;
A second end that is supported by the one end side so as to be vertically movable and rotatable, and the other end side projection is engageable with the thread trimming cam via the engagement hole of the first connecting member. A connecting member;
A driving device that moves the second connecting member up and down to engage and disengage the thread trimming cam and the first connecting member ;
The link mechanism is
A first link consisting of two plate-like links that drive the moving knife of the first hook and adjust its connecting length;
A second link consisting of two plate-like links that drive the moving knife of the second hook and adjust the connecting length;
At least one of the plate links of the first link and the second link has the same length.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a thread cutting device for a two-needle sewing machine according to the present invention will be described with reference to FIGS. The two-needle sewing machine in which this thread trimming device is incorporated is composed of two left and right needles that reciprocate in conjunction with the main shaft, two left and right shuttles that cooperate with the needles to form a seam, and a pair of thread tension plates. A thread loosening mechanism that relaxes the tension of the thread held between the two.
[0017]
Each hook is attached to two hook shafts 8A and 8B. Two swing shafts 101A and 101B are rotatably attached to the shuttle shaft bases 8A and 8B, respectively, and a moving knife for cutting the upper and lower threads is attached to the swing shafts 101A and 101B. The lower shaft 32 is fixed with a thread trimming cam 102 for moving the moving knife and performing thread trimming, and a thread loosening cam 103 for operating the thread loosening mechanism in conjunction with the thread trimming operation. The thread loosening cam 103 is disposed on the side opposite the hook relative to the thread trimming cam 102.
[0018]
A solenoid mounting plate 104 is fixed to the sewing machine frame 1, and a solenoid 105 and a support shaft 106 are fixed to the solenoid mounting plate 104, respectively. The solenoid 105 has its output shaft 105A disposed along the vertical direction. A fulcrum shaft 107 is attached to the solenoid mounting plate 104, and one end of the drive arm 108 is rotatably supported by the fulcrum shaft 107.
[0019]
The other end of the drive arm 108 is engaged in a recess provided at one end of a roller pushing arm (second connecting member) 110 attached to the support shaft 106 so as to be movable up and down. A rectangular guide portion 110A and a cylindrical roller 110B are provided on the other end side of the roller pushing arm 110. The output shaft 105A of the solenoid 105 is located between both ends (substantially in the middle) of the drive arm 108, and the output shaft 105A and the drive arm 108 are rotatably connected via a pin 109.
[0020]
Further, a transmission arm (first connecting member) 111 is disposed on the support shaft 106 below the roller pushing arm 110, and one end thereof is rotatably supported. The transmission arm 111 has an engagement hole 111A at a position corresponding to the guide portion 110A of the roller pushing arm 110 and is connected to the plate-like link 112 at the other end. The engaging hole 111A has a long hole shape, and its width W1 is slightly larger than the width W2 of the guide portion 110A of the roller pushing arm 110.
[0021]
The thread trimming cam 102 is disposed below the roller 110B of the roller pushing arm 110 so that the roller 110B and the cam groove 102A can be engaged with each other. In a normal state, the roller 110B is detached from the cam groove 102A, but engages at the time of thread trimming.
[0022]
The other end of the plate-like link 112 is connected to a plate-like link 113 having an elongated hole 113A, and this plate-like link 113 is connected to one swinging shaft 101A. These plate-like links 112 and 113 constitute a first link and drive a moving knife of one hook, and the connection length thereof can be adjusted by a long hole 113A and a set screw 113B.
[0023]
One swinging shaft 101A is further connected to a plate-like link 114, and this plate-like link is connected to a plate-like link 115 having an elongated hole 115A. This plate-like link 115 is connected to the other swing shaft 101B. These plate-like links 114 and 115 constitute the second link and drive the moving knife of the other hook, and the connecting length thereof can be adjusted by the elongated hole 115A and the set screw 115B.
[0024]
When changing the width of the two needles, the width of the hook shafts 8A and 8B will be changed in the same way, so it is necessary to adjust the length between the centers of the first link and the second link. At this time, the connection length is adjusted by the long holes 113A and 115A and the set screws 113B and 115B.
[0025]
In the present embodiment, among the plate links 112 to 115 of the first link and the second link, the plate links 113 and 115 having the long holes 113A and 115A have the same length. Therefore, it is possible to reduce the cost due to the common use of parts.
[0026]
A thread release arm 121 is rotatably attached to a thread release support shaft 120 fixed to the solenoid mounting plate 104. This thread loosening arm 121 is configured to move up and down as the drive arm 108 moves up and down. A roller 121A that can be engaged with the thread releasing cam 103 is attached to one end side of the thread releasing arm 121, and a wire 122 is fixed to the other end side. Normally, the roller 121A is detached from the thread loosening cam 103. However, when the solenoid 105 is operated and the tip of the driving arm 108 is lowered at the time of thread trimming, the roller 121A is lowered to engage with the thread loosening cam 103. .
[0027]
Next, the operation of the embodiment having the above configuration will be described. When the pedal provided at the bottom of the table (not shown) is operated to stop the sewing machine operation, a signal is transmitted to the control circuit of the needle position stop motor, and the needle bar is in the state near the lowest point. Operation stops.
[0028]
Next, when the pedal is operated to perform the thread trimming, the sewing machine that receives the thread trimming signal starts rotating at a low speed. At the same time, the output shaft 105A of the solenoid 105 that has received the thread trimming signal descends and pushes down the front end side of the drive arm 108. As a result, the roller 121 </ b> A descends and engages with the thread loosening cam 103 as described above. Then, the thread releasing arm 121 rotates counterclockwise in FIGS. 1 and 2 along the shape of the thread releasing cam 103, so that the wire 122 fixed to the other end of the thread releasing arm 121 rotates the lower shaft 32. Accordingly, the pair of tension plates connected to the wire 122 are pulled in the direction of the arrow C, and the tension of the upper thread that has been clamped is released.
[0029]
Simultaneously with the engagement of the roller 121A and the thread loosening cam 103, the roller pushing arm 110 descends along the support shaft 106, and the roller 110B engages with the cam groove 102A of the thread trimming cam 102, so that the cam phase is reached. Accordingly, the roller pushing arm 110 swings around the support shaft 106. At this time, since the guide portion 110A is engaged with the engagement hole 111A, the transmission arm 111 also swings around the support shaft 106 and interlocks the plate-like link 112. Then, the moving knife in the vicinity of one hook moves via the plate-like link 113 and one swinging shaft 101A, and the upper and lower threads are cut. At the same time, the moving knife in the vicinity of the other hook moves through the plate-like links 114 and 115 and the other swinging shaft 101B to cut the upper and lower threads. In the present embodiment, the link for driving the moving knife of the left and right hooks can be formed in a plate shape in this way, so that the cost can be reduced.
[0030]
In this embodiment, the roller 110B is engaged with the thread trimming cam 102 by using the roller pushing arm 110 that is separate from the transmission arm 111, so that the transmission arm 111 is moved up and down to swing the transmission arm 111. There is no need to move it. For this reason, it is not necessary to use an expensive spherical bearing for the connection between the transmission arm 111 and the plate-like link 112.
[0031]
Further, since the fulcrum shaft 107 of the driving arm 108 is provided on the opposite side of the roller pressing arm 110 with respect to the solenoid 105, the stroke of the solenoid 105 can be amplified. That is, if the total length of the drive arm 108 is L1, and the distance between the fulcrum shaft 107 and the output shaft 105A is L2, the drive arm that engages with a recess at one end of the roller push arm 110 with respect to the vertical movement stroke of the output shaft 105A. The vertical movement stroke at the tip of 108 is amplified to L1 / L2. For this reason, the solenoid 105 can be reduced in size. Further, since the solenoid 105 is arranged with its output shaft 105A along the vertical direction, the space can be saved. In particular, in the case of a two-needle sewing machine, space saving is a great effect because of the provision of the two shuttle shaft bases 8A and 8B.
[0032]
Further, the thread loosening cam 103 is arranged in a direction opposite to the shuttle shaft base 8 relative to the thread trimming cam 102. For this reason, since the arrangement of the thread trimming mechanism and the thread loosening mechanism does not intersect, the structure becomes simple and the assembly is facilitated.
[0033]
As mentioned above, although this invention was demonstrated based on embodiment shown in drawing, it is not limited to embodiment of this invention box, A various deformation | transformation is possible. For example, an example in which the direct acting solenoid 105 is used as a driving device for moving the roller pushing arm 110 up and down to engage and disengage the thread trimming cam 102 and the transmission arm 111 has been shown. Also good.
[0034]
【The invention's effect】
According to the present invention, one end side is connected to the moving knife through the link mechanism and has an engagement hole, and the one end side is supported so as to be movable up and down and pivotable about the one end side. The end protrusion is provided with a second connecting member that can be engaged with the thread trimming cam through the engaging hole of the first connecting member, and the driving device moves the second connecting member up and down, Since the thread trimming cam and the first connecting member are engaged and disengaged, there is no need to move the first connecting member up and down. Therefore, since it is not necessary to use an expensive spherical bearing for connecting the first connecting member and the link mechanism, the cost can be reduced.
[0038]
The link mechanism drives a moving knife of a first hook and drives a first link formed of two plate-like links whose connecting lengths can be adjusted, and a moving knife of a second hook, and connects them. A second link comprising two plate-like links whose lengths can be adjusted, and at least one of the first links and each plate-like link of the second link has the same length. In this case, it is possible to obtain an effect of cost reduction due to the fact that the link for driving the two moving knives can be formed into a plate shape and cost reduction due to common use of parts.
[Brief description of the drawings]
FIG. 1 is a perspective view of an embodiment of a thread trimming device for a two-needle sewing machine according to the present invention.
FIG. 2 is a perspective view of a main part of the present embodiment.
FIG. 3 is a plan view of a thread trimming cam and a thread loosening cam according to the present embodiment.
4 is a cross-sectional view taken along line XX in FIG.
FIG. 5 is a perspective view of essential parts of a roller pressing arm and a transmission arm of the present embodiment.
FIG. 6 is a configuration diagram of a conventional thread trimming device for a sewing machine.
FIG. 7 is a cross-sectional view of a conventional thread cutting device for a sewing machine.
FIG. 8 is a configuration diagram of a thread cutting device for a sewing machine according to another conventional example.
FIG. 9 is a plan view of a thread trimming cam and a thread loosening cam of a thread trimming device according to another conventional example.
[Explanation of symbols]
32 Lower shaft 102 Thread trimming cam 103 Thread loosening cam 105 Solenoid 105A Output shaft 106 Support shaft 107 Support shaft 108 Drive arm 110 Roller pushing arm (second connecting member)
110B Roller (protrusion)
111 Transmission arm (first connecting member)
111A engagement hole 112-115 plate-like link (link mechanism)
112, 113 First link 114, 115 Second link

Claims (1)

Two needles that reciprocate in conjunction with the spindle,
Two hooks that cooperate with this needle to form a seam;
Two moving knives provided in the vicinity of each hook to cut the upper and lower threads by movement;
A thread trimming cam fixed to the lower shaft;
A first connecting member having one end side connected to the moving knife through a link mechanism and having an engagement hole;
A second end that is supported by the one end side so as to be vertically movable and rotatable, and the other end side projection is engageable with the thread trimming cam via the engagement hole of the first connecting member. A connecting member;
A driving device that moves the second connecting member up and down to engage and disengage the thread trimming cam and the first connecting member ;
The link mechanism is
A first link consisting of two plate-like links that drive the moving knife of the first hook and adjust its connecting length;
A second link consisting of two plate-like links that drive the moving knife of the second hook and adjust the connecting length;
A thread trimming device for a two-needle sewing machine, wherein at least one of the first link and each plate-like link of the second link has the same length.

Images