JP2005270654A - Buttonhole sewing machine equipped with buttonhole cutting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a buttonhole sewing machine equipped with a buttonhole cutting device. <P>SOLUTION: The buttonhole sewing machine is equipped with a buttonhole cutting device which has a lower cutting tool and an upper cutting tool (24), the upper cutting tool (24) is firmly applied to a cutting tool supporting body (26) with a clamp of a clamping device (48) which can be released so that it can be replaced. The cutting tool supporting body (26) is a holding device (72) which is preferably a permanent magnet (72), the cutting tool (24) is fixed to the cutting tool supporting body (26) at least temporarily, and the clamping device (48) is provided with a holding device (72). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a buttonhole sewing machine with a buttonhole cutting device, the buttonhole cutting device comprising a lower cutting tool and an upper cutting tool, the upper cutting tool being securely and replaceable by a releasable clamping device The cutting tool support is engaged with the lower cutting tool and is movable downward with respect to the lower cutting tool. One cutting tool is a knife, and the other cutting tool is a button hole sewing machine that is a cutting block.

  Patent Document 1 (corresponding to US Pat. No. 6,684,798, Japanese Patent Application Laid-Open No. 2004-8804, Chinese Patent Application Publication No. 1468998, IN277 / KOL / 03), the upper cutting tool changes the cutting force It teaches a general type of buttonhole sewing machine that can be moved by an adjustable drive.

  In practice, button holes of different lengths and / or shapes are required. Button holes of different lengths can be formed by knives of different lengths and cutting blocks of different lengths. If more readily available, the upper cutting tool can be routinely replaced to change the buttonhole length or shape. However, since the sewing machine has very limited space available, in most cases it is necessary to remove the workpiece clamp components on both sides of the cutting tool, which is sufficient to manually replace the upper cutting tool. There is no space. To remove the workpiece clamp component, it is necessary to open the base plate at the top and remove the drive element cover inside the sewing machine. Next, when exchanging the cutting tool, the clamping tool that allows the cutting tool to be clamped with one hand and the tool to be tightened with the other hand is released. This is complicated and time consuming. There is also a risk that the cutting tool will fall into the open base plate, which may occur when a cutting tool that is no longer needed is removed and another cutting tool is inserted.

European Patent Application No. 1371770A

  The object of the present invention is to improve a general type of cutting device so that the upper cutting tool can be replaced with one hand and the risk of the cutting tool falling during replacement is largely eliminated.

  According to the invention, this object is achieved by a cutting tool support comprising a holding device for at least temporarily fixing the cutting tool to the cutting tool support when releasing the clamping device. The inserted cutting tool is securely clamped on the cutting tool support. This is because when the buttonhole is cut or drilled in a clogged or durable, perhaps multi-layered workpiece, considerable distortion is applied to the cutting tool support. When the cutting tool is replaced, the stitcher releases the clamp device with one hand using a screwdriver or a hex key. According to the invention, the cutting tool is held on the cutting tool support even after the clamping device is released. When the cutting tool is temporarily secured to the cutting tool support, the stitcher releases the clamping device with one hand, then removes the cutting tool with the same hand and uses the same hand on one side to create different button holes. Can be exchanged with another cutting tool for use, and there is no need to remove the opposing workpiece clamp parts from the machine.

  According to an advantageous embodiment, the holding system comprises a magnet, preferably a permanent magnet, incorporated in the cutting tool support.

  Advantageously, the temporary fixing of the cutting tool with respect to the cutting tool support can be performed by a holding device comprising a resilient holding mechanism. In this case, the clamping device advantageously comprises a clamping pawl, which can be clamped firmly against the cutting tool by means of a screw, and a compression spring can be arranged between the clamping pawl and the screw.

  Alternatively, the spring can be secured to the cutting tool support, the shape of the spring being adapted to the contour of the cutting tool and pressing the cutting tool in a flexible manner against the cutting tool support.

  Details of the invention will become apparent from the following description of preferred embodiments taken in conjunction with the drawings.

  1 and 2 show a bottom base plate 10 in the form of a casing, a standard 12 projecting upward from one end of the base plate 10, and a horizontal starting from the upper end of the standard 12 and extending parallel to the base plate 10. A basic structure of a buttonhole sewing machine including an arm 14 is shown. The base plate 10, the upright standard 12, and the horizontal arm 14 constitute a customary C-shaped profile in a sewing machine. The working position of the stitcher is located on the left side of FIG. This is the operating side 15.

  Deployment levers 16 that are movable in directions of each other and away from each other protrude from the base plate 10 under the arm 14. The lever 16 serves to actuate two workpiece clamps 18, which can also be deployed when the buttonhole seam 17 is sewn and cut, causing the workpiece 19 to stretch. Further, FIG. 1 shows a needle 20 that sews a buttonhole seam 17 before and after incising a cutout 21 of a buttonhole of a workpiece 19 at a sewing position 23.

  Next, this sewing machine cutting apparatus will be described. The buttonhole cutting portion 21 is created by using a lower cutting tool 22 that is firmly fixed in the base plate 10 and an upper cutting tool 24 that can be lowered on the lower cutting tool 22. In the embodiment shown in FIG. 1, the lower cutting tool 22 is a knife, and the upper cutting tool 24 is a cutting block that constitutes a kind of anvil that cooperates with the knife. The length of the cut portion 21 of the button hole is determined by the length of the knife and the length of the cutting block. If the cutting block is shorter than the knife, there will be no back pressure along part of the knife length and no cut will be made.

  The upper cutting tool 24 is held by a cutting tool support 26, and the cutting tool support 26 is fixed to the lower end of a bar 28 that is guided vertically in a sliding bearing 29.

  The upper end of the bar 28 is connected to a lever 32 via a bracket 30, and the lever 32 is accommodated in the upper arm 14 of the sewing machine and rotates around the shaft 33. The bracket 30 makes it possible to convert the pivoting movement of the lever 32 into the pure vertical movement required for the displacement of the bar 28.

  The pneumatically operated piston cylinder unit 34 operates at the right end of the lever 32, the casing 35 of the unit 34 remains in the base plate 10, and the lower end of the casing 35 pivots around the shaft 35a. The lever 32 can be pivoted by the unit 34. When the piston rod 36 of the unit 34 extends from the housing 35, the lever 32 pivots counterclockwise and the bar 28 moves down with the cutting tool 24.

  As shown in FIG. 2, the workpiece clamp 18 is disposed on both sides of the sewing position 23. Each workpiece clamp 18 has a clamp leg 37 located at the lower end of an individual pivot lever 38 which is also mounted on the lever 16. The two clamp legs 37 are arranged on the workpiece 19 on both sides of the sewing position and then separated by the pivot lever 38, ie left and right in FIG. 2, so that the workpiece 19 extends. .

  In the above range, sewing machines are known. For other details, refer to the above-mentioned Patent Document 1.

  As shown in FIGS. 3 and 4, the cutting tool support 26 includes a guide 39 for accommodating the upper cutting tool 24 that adapts to the cross-sectional shape of the upper head part 40 of the cutting tool 24. Therefore, in FIG. 3, the cutting tool 24 is pushed into the guide 39 from the left side, which is the operation side 15 of the stitcher, and hits the stopper 42 that defines the rightward displacement. As can be seen in FIGS. 5 and 6, the guide 39 of the upper cutting tool 24 includes an upper wall portion 44 and a left wall portion 46 that forms a right angle. The head component 40 can be pushed into this angle using a clamp pawl 48 (FIGS. 4 and 6) which will be described in detail below. The guide 39 and the two walls 44 and 46 are shown below in FIG. 5 (arrow V in FIG. 4). The cutting tool 24 is omitted in the depiction of FIG.

  The essence of the clamping of the cutting tool 24 can be seen especially by looking at FIGS. 4 and 6 in combination.

  Eventually, the cutting tool support 26 protrudes laterally with the guide 39 and the central part 50 including the walls 44, 46 located thereon, and the base plate at the lower end of the bar 28 (FIG. 7) using screws 56. It consists of two connection mechanisms 52, 54 with perforations that allow mounting on 58.

  The stop 42 is part of an angled sheet metal part with a strip 60 provided with an oval hole. The screw 62 is driven from the outside through the elliptical hole of the strip 60 into the side wall 46.

  4 and 6, the clamping claw 48 serving to clamp the cutting tool 24 within the cutting tool support 26 is provided with a protruding cam 64, which is the central part of the cutting tool support 26. 50 recesses 66 enter. Thus, the clamp pawl 48 is roughly arranged. The cutting tool support 26 can be clamped against the cutting tool 24 by means of screws 68 that enter into the central part 50 of the cutting tool support 26, and the cutting tool support 26 comprises two walls 44, 46. It is pressed into the guide 39.

  In one embodiment described in connection with the drawing, if the buttonhole needs to be adjusted again to a longer or shorter length, the cutting block, in this case the upper cutting tool 24, is replaced. Therefore, in this case, it is necessary to fix the tool 70, which is a hex key, and in some cases, a screw driver, to the screw 68. For this work, the sewing element requires the right hand, and at the same time, after releasing the clamp pawl 48, Hold the cutting tool with your left hand and remove it. Although the stitcher requires both hands, there is a risk that the cutting tool will fall into the base plate 10 in the form of a casing that is open when the cutting tool is replaced, even though it is working with both hands. In particular, if the cutting tool is changed frequently, a significant delay can occur.

  According to the present invention, the permanent magnet 72 is incorporated into the upper wall 44 of the guide 39 in the first embodiment. When the cutting tool 24 is assembled, the cutting tool 24 can be pushed into the guide 39 formed by the walls 44 and 46. Next, the ferromagnetic cutting tool 24 is held in the guide 39 by the permanent magnet 72 even if the clamp pawl 48 is not yet fixed. The permanent magnet 72 constitutes a fixing device that temporarily fixes the cutting tool 24 to the cutting tool support 26. This securing device must be designed to hold the dead load of the cutting tool 24 plus a constant increase in safety. Since the cutting tool 24 is subjected to a considerably high load when the sewing machine is operated, the clamping by the clamping claw 48 is indispensable.

  Therefore, the permanent magnet 72 constitutes a holding device that temporarily holds the cutting tool 24 when the cutting tool 24 is replaced.

  Another example of a holding device will become clear from FIGS. In FIG. 6, the screw 68 is slightly loosened, but remains screwed into the corresponding thread in the central part 50. Within the recess 76, the compression spring 74 strikes the outside of the clamp pawl 48 and supports the head 69 of the screw 68 or the washer 78 under the head 69. Thus, the clamp pawl 48 is pushed into the clamp position by an elastic and elastic operation. After the screw 68 is loosened, the cutting tool 24 is still held in place by the spring load by the clamp pawl 48. However, as can be seen in FIG. 6, the cutting tool 24 may be gripped by the deflection of the clamp pawl 48 and the deformation of the spring 74 and removed from the guide 39.

  Other embodiments of a holding device for temporarily holding the cutting tool are conceivable. A resilient holding clamp is envisaged, which applies a spring-loaded pressure on the cutting tool 24 in the angular direction formed by the walls 44, 46 of the guide 39. In some cases, a vacuum mechanism is possible, and the cutting tool 24 is sucked into the guide 39.

  FIG. 7 shows an alternative to FIG. The leaf spring 80 is formed according to FIG. 7 and is angled to match the shape and contour of the head part 40 of the upper cutting tool 24. By means of screws 82, the leaf spring 80 is mounted on the central part 50 of the cutting tool support 26. The leaf spring 80 supports the head part 40 of the upper cutting tool 24 and pushes the head part 40 into an angle formed by the upper wall part 44 and the side wall part 46 so as to flexibly there. Hold. This effect is similar to the effect of the clamp pawl 48 shown in FIG. 6 preloaded in a flexible state.

  The leaf spring 80 must be placed in an area that the clamp pawl 48 does not require. For example, in the side view of FIG. 3, the leaf spring is displaced to the right with respect to the clamp pawl 48, and in the elevation view of FIG.

It is a side view of the buttonhole sewing machine provided with the buttonhole cutting device. It is the elevation which looked at the detail of the buttonhole sewing machine in the direction of arrow II of FIG. FIG. 2 is a view of an upper cutting tool support including an upper cutting tool enlarged compared to FIG. 1. It is the figure which looked at the cutting tool support body containing a cutting tool in the arrow IV direction of FIG. It is the bottom view which looked at the cutting tool support body which does not have a cutting tool in the arrow V direction of FIG. FIG. 5 is a view of a cutting tool support comprising the cutting tool according to FIG. 4 with the clamping device partially released. FIG. 7 is a view corresponding to FIGS. 4 and 6 of a modified embodiment of the cutting tool support. FIG. 6 is a view of a workpiece having buttonhole seams and cut buttonholes.

Explanation of symbols

10 Base plate 12 Standard 14 Upper arm and horizontal arm 15 Sides requiring attention 16 Deployment lever 17 Seam 18 Workpiece clamp 19 Workpiece 20 Needle 21 Button hole cutting part 22 Lower cutting tool 23 Sewing position 24 Upper cutting tool 26 Cutting tool support Body 28 Bar 29 Slide bearing 30 Bracket 32 Lever 33 Shaft 34 Pneumatically operated piston cylinder unit 35 Housing 35a Shaft 36 Piston rod 37 Clamp leg 38 Lever 39 Guide 40 Head part 42 Stopping portion 44 Upper wall portion 46 Side wall Part, left side wall part 48 Clamp claw 50 Central part 52 Connection mechanism 54 Connection mechanism 58 Base plate 60 Strip 62 Strip 64 Projection cam 66 Recess 68 Screw 69 Head 70 Tool 72 Permanent magnet 74 Holding device, compression spring 76 Recess 8 washer

Claims (6)

A buttonhole sewing machine,
A buttonhole cutting device comprising:
-Lower cutting tool (22),
A top cutting tool (24), the top cutting tool (24)
--- applied firmly and interchangeably to the cutting tool support (26) by clamping with a releasable clamping device (48), and
--- movable downward relative to the lower cutting tool (22),
-In a buttonhole sewing machine where one cutting tool (22) is a knife and the other cutting tool (24) is a cutting block,
A holding device (72, 74,) that at least temporarily fixes the cutting tool (24) to the cutting tool support (26) while the cutting tool support (26) releases the clamping device (48). 80) A buttonhole sewing machine comprising:   The buttonhole sewing machine according to claim 1, characterized in that the holding device comprises a magnet (72) incorporated in the cutting tool support (26).   3. A buttonhole sewing machine according to claim 2, characterized in that the magnet is a permanent magnet (72).   The buttonhole sewing machine according to claim 1, characterized in that the holding device (74, 80) comprises a resilient holding mechanism.   The clamping device comprises a clamping pawl (48) applied to the cutting tool (24) by clamping with a screw (68), and a compression spring (74) is formed between the clamping pawl (48) and the screw (68). The buttonhole sewing machine according to claim 4, wherein the buttonhole sewing machine is disposed between the buttons.   A spring (80) is fixed to the cutting tool support (26), the shape of the cutting tool support (26) matches the contour of the cutting tool (24), and the cutting tool (24) is cut into the cutting tool (24). 5. A buttonhole sewing machine according to claim 4, characterized in that it presses against the tool support (26) in a flexible state.

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