JPH036290Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is installed in a so-called pattern stitch sewing machine that holds a workpiece between clamps in which a guide groove is formed and sews the workpiece along the guide groove. This invention relates to a workpiece feeding direction changing device.

[Prior Art] In general, a pattern sewing machine that performs pattern stitching by sandwiching a workpiece using a clamp consisting of two plates with guide grooves formed therein has a mechanism for feeding the workpiece together with the clamp at a bend in the sewing pattern. A work feed direction changing device for changing the direction is provided, and one such as shown in FIG. 2, for example, is currently known.

That is, the sewing machine table T is provided with an arc-shaped guide rail R centered on the falling position of the needle N, a slider a movable along the guide rail R is provided, and the slider a is further connected to the wire W. The wire W is moved by a motor M, and during sewing, the clamp C is moved against the sewing needle N of the sewing machine M in its guide groove g.
When the machine reaches the bend _g1 , the sewing machine M automatically stops, and the motor m moves the slider a to rotate the clamp C so that its guide groove g coincides with the hand movement direction. As a result, a bent-shaped sewing pattern can also be automatically executed.

[Problems to be solved by the invention] However, normally, various mechanisms and devices for operating the sewing machine M are installed on the underside of the sewing machine table T, especially in the vicinity where the sewing machine M is installed. are arranged in a complicated manner, and in order to avoid interference with these, the diameter of the guide rail R had to be made considerably large.

For this reason, the sewing machine table T had to be made larger than necessary, and the processing required to provide the rails R was also extensive and expensive. In addition, as the sewing machine table T becomes larger, it becomes difficult to work, leading to a decrease in productivity, and the diameter of the rail R becomes larger. There was also the inconvenience that it did not get caught in the clamp C, making it impossible to perform a direction change operation.

Others connect one end of the cylinder to the upper surface of the sewing machine table and attempt to rotate the clamp by moving the cylinder rod linearly.

In this case, by changing the direction of the cylinder, it can be applied to clamps of various sizes, but since the cylinder rod pushes out the clamp in a straight line, unreasonable force is applied to the sewing needle. There were problems such as needle breakage and difficulty in changing direction smoothly. This idea was created by focusing on the above-mentioned problems, and it can be easily installed without making any changes to a normal sewing machine, and it does not force the sewing needle to attach, regardless of the size of the clamp. To provide a sewing machine feed direction changing device capable of smoothly changing the feed direction without applying force.

[Means for solving the problem] The sewing machine feed direction changing device according to this invention has the following features:
The first adjacent one of the four connecting shafts of the four-bar link mechanism
and a second connecting shaft is rotatably attached to a predetermined support, an arm is fixed to a third connecting shaft adjacent to the second connecting shaft, and the third connecting shaft is connected from the end of the arm. The distance from the needle drop position to the end of the arm body is set to be the same as the distance between the second connecting shaft and the third connecting shaft, and the distance from the needle drop position to the end of the arm body is set to be the same as the distance between the third connecting shaft and the second connecting shaft. The distance between the axes is set to be the same as that of the four-bar link mechanism, and by moving the four-bar link mechanism, the end of the arm body is brought into contact with the clamp.

[Operation] In this device having the above configuration, the arm body fixed to the third connecting shaft moves the sewing needle along the same arcuate trajectory as the third connecting shaft around the second connecting shaft. Since the sewing needle is drawn at the center, the clamp that comes into contact with this arm rotates smoothly without applying excessive force to the sewing needle.

[Embodiment of the invention] An embodiment of the invention will be described below based on FIG. 1. In the drawings, parts that are the same as or equivalent to those of the above-mentioned conventional example are designated by the same reference numerals.

In the figure, reference numeral 1 denotes a first link member, one end of which is connected to the lower surface of a sewing machine table T serving as a support by a first connecting shaft _S1 . 2 is the second
One end of the link member is rotatably connected to the lower surface of the sewing machine table T by a second connecting shaft _S2 . 3 has a third connecting shaft _S3 and a fourth connecting shaft at both ends.
This is the third link member formed by fixing the connecting shaft _S4 . The other end of the second link member 2 is rotatably inserted into the third connecting shaft _S3 , and the other end of the second link member ₂ is rotatably inserted through the fourth connecting shaft S2. Further, the upper end of the third connecting shaft _S3 projects upward from the hole Ta formed in the table T.

The above link members 1, 2, 3 and the connecting shaft S ₁ ,
S ₂ , S ₃ , and S ₄ constitute a four-bar link mechanism A.

Further, 4 is a rod-shaped arm fixed to the upper end of the third connecting shaft _S3 , and a rotor 4a is attached to the lower surface of the tip.
is provided in a protruding manner, and has the following dimensional and positional relationship with respect to the third link member 3 and the sewing needle N. That is, the distance from the tip of the arm 4 to the third connecting shaft _S3 is set to be the same as the distance from the needle drop position P to the connecting shaft S2, and the distance from the needle drop position P to the _third connecting shaft S3 is set to be the same as the distance from the needle drop position P to the third connecting shaft S3. The distance to the tip is the third connecting shaft S ₃
and the second connecting shaft _S2 .

Reference numeral 5 denotes a cylinder as a moving means operated by a drive device (not shown), the rear end of which is rotatably connected to the lower surface of the sewing machine table T, and the tip of the cylinder rod 5a connected to the third connection. shaft
It is rotatably connected to _S3 . In addition, in the figure,
Cg is a circular clamp guide formed around the needle hole Na of the throat plate, and is designed to be inserted into the guide groove g of the clamp C without any gap.

Based on the above configuration, the operation will be explained next.

When the clamp guide Cg is inserted into the end of the guide groove g and the sewing start switch is operated, the clamp is linearly fed by the operation of the feed dog and sewing is performed. When the clamp C reaches the bent portion _g1 of the guide groove g, the sewing machine M automatically stops with the sewing needle N passing through the workpiece W. Thereafter, the cylinder 5 is driven by a drive means not shown.
is activated, the cylinder rod 5a protrudes, and the four-bar connection mechanism A is moved. At this time, the third connecting shaft S ₃
Since the arm body 4 rotates while drawing an arcuate trajectory around the second connection axis S ₂ , the arm body 4 also rotates while drawing an arc of the same diameter. As a result, the slider 4a pushes the side surface of the clamp C, rotates the clamp C around the sewing needle N, and stops the operation when the direction of needle movement and the direction of formation of the guide groove g match, and then,
Start sewing operation again.

By the way, the arm body 4 is rotatably connected to the second link, and a third connecting shaft fixed to the arm body 4
Since S ₃ is fixed to the third link 3 which moves in parallel by the first link, the rotor 4a of the arm body 4
, the clamp C is pushed out while drawing an arcuate locus approximately centered on the needle N, and the direction can be changed smoothly without any excessive force being applied to the sewing needle.

Note that the radius of rotation of the arc drawn by the slider 4a is determined by the distance between the second connecting shaft _S2 and the first connecting shaft _S1 , so when using a small clamp, this A link member with a narrow distance between axes may be used. Therefore, if the distance between the axes can be changed by, for example, providing a long hole in the first link member 1, it is possible to easily accommodate clamps having various sizes. In addition, in the above embodiment, the connecting shafts S ₁ and S ₂ of the four-bar link L are installed on the bottom surface of the cylinder, but they can also be installed at other locations as appropriate depending on the configuration and shape of the sewing machine. Can be changed.

[Effects of the invention] As explained above, according to this invention, it can be easily installed without making any changes to a normal sewing machine, and it can also be applied to clamps of various sizes. This has the advantage of being able to smoothly change the feeding direction without applying excessive force to the sewing needle when moving the clamp.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of this invention;
FIG. 2 is a perspective view showing a conventional sewing machine feed direction changing device. {1...First link member, 2...Second link member, 3...Third link member, 5...Cylinder, _S1 ...First connection shaft, _S2 ...Second link member connection shaft,
S ₃ ...Third connection shaft, S ₄ ...Fourth connection shaft}L:
Four-bar link mechanism, 4...arm body, C...clamp,
g... Guide groove, g ₁ ... Bent part of the guide groove.

Claims (1)

[Scope of Claim for Utility Model Registration] A clamp guide formed around a needle hole provided in the throat plate of a sewing machine, a clamp for holding a cloth in which a guide groove having a bent shape that plays with the clamp guide is formed, and a sewing machine table. a first link and a second link that are rotatably supported at one end of each and separated from each other; and a third link that is rotatably supported at the other end of the second link.
a connecting shaft, an arm body having one end fixed to the third connecting shaft and having a rotor at its tip that contacts the peripheral edge of the clamp; one end rotatably supported by the first link, the other It consists of a third link whose end is fixed to a third connecting shaft, and a moving means for rotating the second link,
A work feed direction changing device for a sewing machine, characterized in that a rotor of an arm body draws a trajectory centered on a needle hole by the operation of a moving means, and a clamp is rotated centering on the needle hole.