JP5969202B2 - Sewing machine cloth cutting equipment - Google Patents

Description

  The present invention relates to a cloth cutting device for a sewing machine.

Conventionally, as a cloth cutting device of this type of sewing machine, there is known a cloth cutting device in which a cloth guide portion is provided on a presser foot of a sewing machine and a cloth fed into the cloth guide portion is cut by a fixed knife and a movable knife. (For example, refer to Patent Document 1).
As shown in FIG. 4, the conventional cloth cutting device is provided with a presser shaft 5 (presser bar) that protrudes downward from the head 3 of the sewing machine so as to be movable up and down. 6 is attached. The presser foot 6 is provided with a cloth guide portion 8 (fabric guide passage) between the presser feet 6a and 6b branched to the left and right, a fixed knife 7 is fixed to the presser foot 6a, and a movable knife 15 is mounted on the presser foot 6b. It is arranged to be movable.

  A cylindrical base end portion of a movable knife driving arm (not shown) is fitted on the outer periphery of the presser shaft 5 so as to be rotatable around the presser shaft 5. The movable knife drive arm is connected to a drive transmission mechanism (not shown), and rotates and swings around the presser shaft 5 in conjunction with the drive of the sewing machine. A connecting member 10 is fixed to the movable knife driving arm, and a movable knife support shaft 13 (operating rod) is pivotally supported on the coupling member 10 so as to be movable up and down. 14 is attached. The base end of the movable knife 15 is attached to the lower end of the movable knife support shaft 13, and the movable knife 15 is urged downward by a knife pressure adjusting spring 28 (coil spring). The fixed knife 7 is arranged below the movable knife 15 so that a part thereof overlaps the movable knife 15. The movable knife 15 applies a pressing force by the elasticity of the knife pressure adjusting spring 28 to the fixed knife 7. Hereinafter, the force with which the movable knife 15 presses the fixed knife 7 is referred to as knife pressure. With the above configuration, the movable knife 15 moves to the left and right while sliding on the upper surface of the fixed knife 7 in conjunction with the driving of the sewing machine, and the upper end of the cloth C sent to the cloth guide portion 8 is moved by the fixed knife 7 and the movable knife 15. It is trimmed.

Japanese Patent Laid-Open No. 2001-137581

  Due to the structure of the cloth cutting device, both the scalpels are in sliding contact with the scalpel pressure, so that the scalpel is worn. The cloth cutting device is likely to cause wear of the knife as compared with a known overlock sewing machine that does not generate knife pressure. The higher the knife pressure, the more the knife wear is promoted.

  In the cloth cutting device, the fixed knife fixed to the presser moves up and down together with the presser by the feed dog protruding and protruding from the upper surface of the needle plate when the sewing machine is driven. Since the movable knife as well as the fixed knife moves up and down against the elasticity of the knife pressure adjusting spring, the knife pressure increases when both the knife rises. In other words, due to the structure of the cloth feeding device, the presser foot moves up and down due to the feed dog protruding and retracting from the upper surface of the needle plate when the sewing machine is driven, so that the knife pressure is periodically increased and the wear of the knife is promoted. It was.

  Furthermore, in the cloth feeding device, when the cloth is fed into the cloth guide portion of the presser foot, the presser foot and the fixing knife rise by the thickness of the cloth. Since the movable knife as well as the fixed knife rises against the elasticity of the knife pressure adjusting spring, the knife pressure increases. The greater the thickness of the cloth fed into the presser foot cloth guide, the higher the knife pressure. Therefore, in the conventional cloth cutting device, in order to suppress wear of the knife, the attachment position of the locking piece to the movable knife support shaft is changed according to the thickness of the cloth fed to the cloth guide portion of the presser foot, It was necessary to adjust the pressure.

  Therefore, an object of the present invention is to prevent the wear of the knife from being promoted by the vertical movement of the presser foot when the sewing machine is driven, and to reduce the wear of the knife to reduce the wear of the presser foot. An object of the present invention is to provide a cloth cutting device for a sewing machine that does not require the knife pressure to be adjusted according to the thickness.

The cloth cutting device for a sewing machine according to claim 1,
A presser shaft provided on the head of the sewing machine so as to be movable in the vertical direction;
A presser foot that is provided at the lower end of the presser shaft and forms a presser foot that branches to the left and right;
A fixed knife fixed to one of the presser feet and moving up and down with the presser foot;
A movable knife driving arm fitted on the presser shaft;
A connecting member attached to the lower end of the movable knife driving arm;
A movable knife support shaft that is supported by the connecting member so as to be vertically slidable and has a fixed piece at the lower end ;
The fixed knife is attached to the fixed piece , and is arranged to overlap the other of the presser foot and a fixed knife, and the movable knife driving arm rotates and swings around the presser shaft in conjunction with the driving of the sewing machine. A movable knife that moves left and right while sliding on the fixed knife while pressing
In the cloth cutting device of the sewing machine that cuts the cloth fed into the cloth guide provided between the presser feet by the fixed knife and the movable knife,
A pressing plate fixed to the upper surface of the fixing piece;
A force adjusting device that can arbitrarily set a force for pressing the movable knife against the fixed knife and can be held constant ;
The knife pressure adjusting device is
An air cylinder coupled to the movable knife driving arm;
A regulator connected to the air cylinder and supplying air with a constant pressure controlled to the air cylinder;
The tip of the telescopic rod that protrudes downward from the air cylinder is disposed so as to contact the upper surface of the pressing plate, and the pressing plate is pushed down by the air cylinder by the air pressure to fix the movable knife. It is comprised so that it may press on a knife .

The cloth cutting device for a sewing machine according to claim 2,
The knife pressure adjusting device is
An air cylinder that presses the movable knife against the stationary knife by means of a telescopic rod;
And a regulator connected to the air cylinder and supplying air with a constant pressure controlled to the air cylinder.

  According to the present invention, since the knife pressure can be kept constant even if the presser foot is moved up and down during driving of the sewing machine or the cloth is fed into the cloth guide portion of the presser foot, the fixed knife and the movable knife are worn. Is reduced and the durability of the knife is improved.

1 is an external perspective view showing a delivery arm type sewing machine according to an embodiment of the present invention. It is a disassembled perspective view which shows a movable knife mechanism. It is the schematic which shows a knife pressure adjusting device. It is a perspective view which shows the cloth cutting device of the delivery arm type sewing machine of a prior art example.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. FIG. 1 is an external perspective view showing a delivery arm type sewing machine according to an embodiment of the present invention. FIG. 2 is an exploded perspective view showing the movable knife mechanism A. FIG. FIG. 3 is a schematic view showing the knife pressure adjusting device B.

  As shown in FIG. 1, the cylinder 1 is formed so as to extend along the cloth feeding direction X, and a base end of a bed 2 is erected on the base end side of the cylinder 1. It is comprised so that it may extend horizontally in the direction which cross | intersects the extension direction. A head 3 is connected to the tip of the bed 2 so as to extend upward on the tip side of the cylinder 1. A presser shaft 5 is arranged on the head 3 so as to be movable in the vertical direction. The lower end portion of the presser shaft 5 protrudes downward from the lower wall of the head 3, and a presser foot 6 is attached to the protruding lower end portion. With respect to the presser foot 6 in the embodiment of the present invention, portions common to the prior art shown in FIG. 4 will be described below using the same reference numerals as in FIG. The presser foot 6 is provided with a cloth guide portion 8 between presser feet 6a and 6b branched to the left and right, and a fixing knife 7 is fixed to one presser foot 6a. The presser foot 6 can be separated upward from the cylinder 1 in conjunction with the operation of a presser lever (not shown).

  Next, the movable knife mechanism A will be described. A movable knife driving arm 9 as shown in FIG. 2 is externally fitted to the presser shaft 5, and the movable knife driving arm 9 is connected to a drive transmission mechanism (not shown) in the head 3. The movable knife driving arm 9 has an arm portion 9a at the lower end, and the connecting member 10 is attached to the arm portion 9a. A movable knife support shaft 13 is slidably supported on the connecting member 10 through a pair of support holes 12, 12 formed vertically, and a locking piece 14 is provided in the middle of the movable knife support shaft 13. It is attached.

  A fixed piece 13a is formed at the lower end of the movable knife support shaft 13, and a proximal end of the movable knife 15 is attached to the fixed piece 13a. The fixed piece 13a and the movable knife 15 are fitted into a knife holder 16, and the knife holder 16 is fixed to the fixed piece 13a with screws 11, 11. The distal end side of the movable knife 15 is disposed on the presser foot 6b, and the horizontal movement of the movable knife 15 is performed near the presser foot 6 when the sewing machine is driven. As described above, due to the configuration of the movable knife mechanism A, the movable knife driving arm 9 rotates and swings around the presser shaft 5 via the drive transmission mechanism in conjunction with the drive of the sewing machine, and the movable knife 15 is fixed to the fixed knife 7 of the presser foot 6. It moves forward and backward while sliding on the fixed knife 7 while pressing.

  As shown in FIG. 2, a bracket 17 is fixed to the arm portion 9 a of the movable knife driving arm 9 with screws 18, 18. An air cylinder 19 is attached to the bracket 17 in the vicinity of the arm portion 9 a and above the movable knife 15. It is fixed with screws 20, 20 so as to be arranged in The bracket 17 is provided with two screw holes for the screws 18 and 18 on the left and right sides, and the screw holes for the screws 20 and 20 are provided with long and long long holes. It can be adjusted left and right. A pressing plate 25 is disposed below the air cylinder 19, and the pressing plate 25 is fixed to the upper surface of the fixed piece 13 a of the movable knife support shaft 13 with a screw 26. The distal end portion of the telescopic rod 19 a that protrudes downward from the air cylinder 19 is disposed so as to contact the upper surface of the pressing plate 25. The pressing plate 25 is configured to be pressed down by the air pressure of the air cylinder 19 via the telescopic rod 19 a and press the movable knife 15 against the fixed knife 7.

  Next, the knife pressure adjusting device B will be described. The knife pressure adjusting device B includes an air cylinder 19, a regulator 22, a compressor 24, an air tube 21 and an air tube 23. The air cylinder 19 and the regulator 22 are the air tube 21, and the regulator 22 and the compressor 24 are the air tube 23, respectively. It is connected. The compressor 24 is provided as a supply source of air necessary for driving the air cylinder 19. The pressure of the air supplied to the air cylinder 19 is kept constant at an arbitrary value by the regulator 22. Then, the telescopic rod 19 a pushes down the pressing plate 25 by the air supplied to the air cylinder 19, and the movable knife 15 presses the fixed knife 7. That is, the knife pressure at which the movable knife 15 presses the fixed knife 7 is adjusted by the set value of the regulator 22.

  With the above-described configuration of the knife pressure adjusting device B, the knife pressure is kept constant even when the presser foot 6 and the fixed knife 7 are moved up and down due to the feed dog (not shown) protruding from the upper surface of the needle plate (not shown) when the sewing machine is driven. Can be held in. Further, according to the knife pressure adjusting device B, the knife pressure can be kept constant regardless of the thickness of the cloth fed into the cloth guide portion 8. Therefore, the cloth cutting device provided with the knife pressure adjusting device B can reduce the wear of the fixed knife 7 and the movable knife 15 and improve the durability of both the knife compared with the conventional cloth cutting device. As the regulator, it is desirable to use a precision regulator that is highly responsive to pressure fluctuations.

1 cylinder 2 bed 3 head 6 presser foot 7 fixed knife 9 movable knife drive arm 15 movable knife 17 bracket 19 air cylinder 22 regulator 25 pressing plate A movable knife mechanism B knife pressure adjusting device

Claims (1)

A presser shaft provided on the head of the sewing machine so as to be movable in the vertical direction;
A presser foot that is provided at the lower end of the presser shaft and forms a presser foot that branches to the left and right;
A fixed knife fixed to one of the presser feet and moving up and down with the presser foot;
A movable knife driving arm fitted on the presser shaft;
A connecting member attached to the lower end of the movable knife driving arm;
A movable knife support shaft that is supported by the connecting member so as to be vertically slidable and has a fixed piece at the lower end ;
The fixed knife is attached to the fixed piece , and is arranged to overlap the other of the presser foot and a fixed knife, and the movable knife driving arm rotates and swings around the presser shaft in conjunction with the driving of the sewing machine. A movable knife that moves left and right while sliding on the fixed knife while pressing
In the cloth cutting device of the sewing machine that cuts the cloth fed into the cloth guide provided between the presser feet by the fixed knife and the movable knife,
A pressing plate fixed to the upper surface of the fixing piece;
A force adjusting device that can arbitrarily set a force for pressing the movable knife against the fixed knife and can be held constant ;
The knife pressure adjusting device is
An air cylinder coupled to the movable knife driving arm;
A regulator connected to the air cylinder and supplying air with a constant pressure controlled to the air cylinder;
The tip of the telescopic rod that protrudes downward from the air cylinder is disposed so as to contact the upper surface of the pressing plate, and the pressing plate is pushed down via the telescopic rod by the air pressure of the air cylinder to fix the movable knife. A sewing machine cloth cutting device characterized by being configured to press against a knife .

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