JPH0337959B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fabric shift prevention device for preventing fabric from shifting during sewing with a sewing machine.

[Conventional technology]

Generally, a sewing machine is provided with a presser foot that presses the vicinity of the needle drop point of the fabric to be sewn.

However, when a stepped portion is formed in the fabric, such as when sewing the hem of pants, the stepped portion W ₁ of the fabric W as shown in FIGS. 3a and 3b.
When the presser foot P approaches the presser foot P, the pressure force applied to the fabric by the presser foot P becomes biased, causing the fabric W to shift in the direction perpendicular to the raphe line l (in the direction of the arrow a), resulting in the problem that proper sewing cannot be performed. occured.

Therefore, conventionally, the driving speed of the sewing machine is lowered before the presser foot P reaches the step W ₁ of the fabric W, and using a perforator, scissors, etc. nearby, the sewing machine is used to cut the step W ₁ of the fabric W from the side of the presser foot P. Sewing was carried out while pressing against the fabric to prevent it from slipping.

[Problem that the invention seeks to solve]

For this reason, extreme caution is required in the work, and the sewing machine must be driven at a low speed when sewing the stepped portion _W1 , resulting in a decrease in productivity.

Furthermore, in the case of a so-called automatic machine that automatically performs sewing at a predetermined speed, it is impossible for the operator to make any changes to _the sewing machine. Quality was severely compromised.

This invention was made by focusing on the above-mentioned problems, and provides a sewing machine that can easily prevent the fabric from shifting due to the pressing force of the presser foot and can form a good seam when sewing stepped sections of fabric. The purpose is to provide a fabric shift prevention device.

[Means for Solving the Problems] This invention raises and lowers together with the lifting member held in the sewing machine main body, and when lowered, presses the sides of the fabric pressing area by the presser foot, and can move horizontally along the fabric feeding direction. It is equipped with a pressing locking member.

[Effect]

In this invention, when sewing the stepped portion of the fabric to be sewn, the sides of the presser foot are locked by the pressure locking members, so the fabric does not shift to the sides, and moreover, it is difficult to feed the fabric. Since the pressing locking member also moves horizontally, the feeding of the fabric is not hindered.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.
This will be explained based on the diagram.

In the figure, 1 is a sewing machine main body, 2 is a presser bar provided on the sewing machine main body 1, and a well-known presser foot 3 is fixed to the lower end of the bar, which can be raised and lowered by vertical operation of an operating lever (not shown). It's summery. Reference numeral 4 denotes a mounting plate fixed to the presser foot 3, and a cam portion 4a having a bent shape is bent at the side end thereof. 5 and 6 are links each having one end rotatably connected to the mounting plate 4; 7 is the link 5;
The lifting member is rotatably connected to the other end of 6, and the mounting plate 4 and the links 5 and 6 form a four-bar link mechanism. It is now movable. Reference numeral 8 denotes a lifting spring installed between the upper end 4b of the mounting plate 4 and the upper side 7a of the lifting member 7, and these 5, 6, 7, and 8 constitute the lifting member. Reference numeral 9 denotes a presser arm that supports the roller 10 at its upper end and rotatably supports the presser teeth 11 at its lower end. A long hole 9a is formed in the middle of the presser arm. A locking pin 4c protruding from the mounting plate 7 is inserted into the locking pin 4c. Further, the lower surface of the presser teeth 11 has a sawtooth shape extending along a direction parallel to the conveying direction A of the cloth and providing resistance so as to prevent the cloth from moving in the direction of arrow a (FIG. 3). A groove 11a is formed. These 4 and 9 constitute a holding member. Reference numeral 12 denotes a presser spring installed between the support shaft 10a of the roller 10 and the lower end 4d of the lifting member 7, which presses the presser arm 9 downward against the lifting member 7. Reference numeral 13 denotes an elevating lever protruding from the side surface of the elevating member 7, and the operator holds this lever 13 to move the elevating member 7 up and down.

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

When the elevator lever 13 is pushed upward in the state shown in FIG. 1, the elevator member 7 is moved upward in parallel by the links 5 and 6 while tracing an arcuate trajectory.

During this time, the lifting spring 8
It acts to push down the elevating member 7 to the point where it is extended to the maximum, and after that point
(Hereinafter, the above point will be referred to as a biasing direction switching point.) Due to the biasing force of the lifting spring 8, the lifting member 7 moves the links 5 and 6.
is held at the top dead center of rotation. As a result, the presser arm 9 is also held upward by the locking pin 4c of the elevating member 7.

Normally, when sewing a flat part of the fabric W, the press locking member 9 is raised as described above, and the presser foot 3 is
Sew while pressing the fabric W with a chisel.

When the stepped portion _W1 of the fabric W has advanced to the front of the presser foot 3, the elevator lever 13 is pushed down. At this time, the elevating member 7 first moves downward against the urging force of the elevating spring 8, and after passing the aforementioned urging direction switching point, it is urged by the elevating spring 8 and moves downward. . At the same time, the presser arm 9 also lowers the elevating member 7, and the presser teeth 11 provided at the tip descend to the front side of the presser foot 3.
Press the stepped portion _W1 of the dough W. Since a groove 11a is formed on the lower surface of the presser tooth 11 along the cloth feeding direction A, the cloth _W1 pressed by this groove is completely moved in the direction of the arrow a (crossing the cloth feeding direction A). movement in the direction) is prevented. Therefore, even if the presser foot 3 rides on the stepped portion _W1 of the fabric W and pushes the fabric W to the side due to the deviation of its pressing force, the fabric W will not shift and the sewing will proceed as planned. You can get the line.

Further, the presser arm 9 is pressed against the stepped portion by a pressing spring 12.
Since it moves horizontally with the fabric W while holding down _W1 , the conveyance of the fabric W is not hindered. In addition, at this time, the press locking member 9 moves using the locking pin 4c fitted into the elongated hole 9a as a fulcrum,
The roller 10 provided at the upper end abuts the lower part of the cam portion 4a of the mounting plate 4.

Then, when the stepped portion W ₁ passes the presser foot 3, the operator pushes the lifting lever 13 upward again, raises the presser arm 9 together with the lifting member 7, and holds it at the top dead center. At this time, the presser arm 9 rotates around the locking pin 4c and returns to its initial position because the roller 10 provided at its upper end moves while being restricted by the inner surface of the cam 4a.

In addition, in the above embodiment, the elevating lever 13
Although we have described the case where the lifting lever 13 is manually operated using a predetermined actuator, it is possible to operate the lift lever 13 using a predetermined actuator, and furthermore, the operation of the actuator can be controlled using a predetermined step detection sensor to completely It is possible to automate.

In addition, in a normal sewing machine, the feed dog is located below the presser foot 3, but the width of the feed dog is
If the length is extended below 1, it is possible to more reliably prevent the fabric from shifting.

〔Effect of the invention〕

As explained above, according to the present invention, when a thick portion of the cloth such as a stepped portion of the cloth moves to a seam portion, the presser member is lowered to a lower position and engaged with the stepped portion. Since the sewing machine moves in the cloth feeding direction along with the cloth while holding down the cloth, it is possible to finish the seam neatly while preventing the fabric from rubbing on the tiered part of the cloth without having to manipulate the cloth by hand, improving work efficiency and sewing. The effect of improving the quality of products can be obtained.

[Brief explanation of the drawing]

Figure 1 is a side view showing an embodiment of the invention, Figure 2 is a side view showing an embodiment of the invention.
The figure is a front view of the thing shown in Figure 1, Figure 3a is a front view showing the state in which the step part is pressed by the presser foot, and Figure 3b
is a side view of FIG. 3a;

Claims (1)

[Scope of Claims] 1. In a sewing machine having a presser foot that is movable up and down and always presses the cloth, presser members 9 and 11 are movable along the cloth feeding direction on the sides of the presser foot, and the presser foot is connected to the throat plate. Lifting means 5, 6, 7, and 8 are movable up and down and can be locked in an upper position where they are held apart from each other and a lower position where they can be pressed against the cloth on the throat plate;
A fabric shift prevention device for a sewing machine, wherein the presser member presses the fabric while moving forward in the fabric feeding direction following the fabric in the lower position. 2. The fabric slippage prevention device for a sewing machine according to claim 1, wherein the lower surface of the presser member is shaped to provide frictional resistance to the fabric in a direction intersecting the fabric feeding direction.