JP3950758B2 - Sewing machine with upper thread clamp and cutter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sewing machine, and more particularly to a buttonhole sewing machine having an upper thread clamp cutter.
[0002]
[Prior art]
German patent specification 197 22 504 (corresponding to US Pat. No. 5,931,106) teaches a universal sewing machine, in particular a buttonhole sewing machine, with the following components: That is,
-A needle that can be driven to reciprocate up and down along the path of travel;
-With hooks;
-A workpiece holding plate for holding and guiding the workpiece under the needle during the sewing operation;
-The workpiece holding plate has a recess through which the needle passes during seam production;
-Also, a drive mechanism for the workpiece holding plate;
-With an upper thread clamp and cutter,
-The upper thread clamp / cutter has an upper thread clamp, and the upper thread clamp
--- a lower half with a cutting blade in the tip,
--- an upper half that is pivoted about the pivot hinge relative to the lower half and has a cutting blade in the tip portion; and
--- With a clamp jaw that can be elastically pressed against the tip of the upper half to hold and hold the tail piece of the upper thread,
--- The upper thread clamp / cutter is adapted to take a working position where the cutting blade is located at least substantially above the recess of the work piece holding plate,
-Also, the upper half is
-The needle travel path is a first open position extending through an upper thread receiving opening formed between the cutting blades; and
-From the first open position where the tip of the upper half is released from the clamping jaws,
-A second closed position where the tip portions overlap at least partially,
-A drive mechanism for rotating to the second closed position where the tip of the upper half is in thread-engaging engagement with the clamp jaw;
-A mechanism for rotating the upper thread clamp from the working position of the cutting blade to the side position above the recess.
[0003]
In the known sewing machine, the movement for operating the upper thread clamping rod is obtained from the control cam and the hook thread cutter. This means that there is a dependency state with respect to the control technique. Therefore, if an exercise pattern is executed on condition that the process is optimized, a problem arises in the upper thread pinching heel. The production, assembly and adjustment of factory equipment should be taken into account. Since the configuration is complicated, the upper thread pinching rod is extremely susceptible to wear. This also affects the reliability of the operation, since a large number of parts are required to implement the working device. In addition, mechanical components require maintenance and lubrication.
[0004]
[Problems to be solved by the invention]
The object of the present invention is to further develop a general-purpose sewing machine so as to obtain a simplification with reduced costs and improved operational reliability.
[0005]
[Means for Solving the Problems]
According to the invention, this object is achieved by the features of the characterizing portion of claim 1. The gist of the present invention is that only two positions of the upper thread clamp must be triggered, which can be implemented by a very simple two-position drive that is triggered independently. This facilitates a reduction in the number of components required and consequently a reduction in wear and costs, thereby increasing operational reliability. Advantageous embodiments will become apparent from the dependent claims.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
As seen in FIG. 1, a stitch group sewing machine in the form of a double thread lock stitch machine, ie a buttonhole sewing machine particularly suitable for linen buttonholes, conventionally has an arm 1 and a substrate in the form of a housing. . An arm shaft 4 that is driven to rotate by a motor 3 is supported on the arm 1 by bearings 5 and 6, and a vertically displaceable needle bar 8 having a needle 9 is applied via a crank driving unit 7. 9 moves up and down in the z direction along a straight movement path. Conventional needle jogging drives (not shown) that generate needle jogging motion are available, thereby creating, for example, zigzag stitches for buttonhole seams.
[0007]
A hook 10 having a yarn supply unit (not shown) is attached to the substrate 2 so as to be rotatable about an axis 11. The action of the hook 10 is conventionally obtained from the arm shaft 4 in synchronism with the movement of the needle bar 8. The configuration of the hook 10 and the hook thread cutter can be shown and specified, for example, in German patent specification 197 22 504 (corresponding to US Pat. No. 5,931,106).
[0008]
A support 12 is formed on the upper side of the substrate 2 under the needle bar 8, and the workpiece 13 is guided and moved by the pressing plate 14 on the support. In order to displace the pressing plate 14 in the x direction, a pressing plate driving mechanism 15 is provided. The presser plate drive mechanism 15 includes a carriage 16 that is disposed on the arm 1 and that can be displaced in the x direction on the guide 17. The carriage 16 is connected to the pressing plate 14 by a continuous bar 18. The operation of the carriage 16 is performed by a stepping motor 19 via a synchronous belt drive unit 20.
[0009]
In the y direction, the upper thread clamp / cutter 21 is located on the needle bar 8 side. This will be described in detail below. The upper thread clamp / cutter 21 has two piston / cylinder drives 22, 23 which are actuated by air pressure, which are actuated by solenoid valves 25, 26 assigned to the central control unit 24. The compressed air is supplied from the compressed air source to the solenoid valves 25 and 26 via the compressed air supply path 27. The driving units 22 and 23 are connected to valves 25 and 26 by flexible compressed air supply conduits 28 and 29.
[0010]
When the solenoid valves 25 and 26 are triggered, the operation is performed via the corresponding electric control lines 31 and 32 by the microprocessor control unit 30 belonging to the control unit 24. In a similar manner, the motor 3 and the stepping motor 19 are triggered by the control unit 30 via the corresponding control lines 33, 34.
[0011]
As can be seen in FIG. 2, the sewing machine has a fabric pressing bar 35 attached to the arm 1, and this pressing bar 35 can be displaced vertically in the z direction, the action of which is in a conventional manner not shown. Done. The fabric pressing bar 35 and the needle bar 8 are parallel to each other.
[0012]
A bearing box 36 is fixed to the lower end of the fabric pressing bar 35 by a set screw 37. On the bearing box 36, a pressure roller 38 is held by a bolt 39 so as to be freely rotatable. When the fabric presser bar 35 is lowered in the direction of the substrate, the pressure roller 38 presses the presser plate holder 40. It is joined to the plate 14. When the fabric pressing bar 35 is lowered as described above, the pressing plate 14 with the workpiece 13 underneath is pressed and held on the support 12 of the substrate 2. A concave portion 42 that travels in the x direction is provided in the pressing plate 14 so that the needle can pass therethrough.
[0013]
Furthermore, a buttonhole cutter can be provided on the arm 1, as is known, for example, from the above-mentioned German patent specification 197 22 504 (US Pat. No. 5,931,106). Next, referring to FIG. 2, the upper thread clamp / cutter 21 has an upper thread clamping bar 43, and the upper thread clamping bar 43 is inserted into the bearing box 36 by the insertion of the rotation lever 44, with a shaft 45 extending in the x direction as the center. It is pivotally attached. The eaves 43 can be moved in the y direction from the operating position (FIGS. 2, 3 and 5) to the side position (FIG. 4) and rotated by the lever 44 in the opposite direction. For this purpose, the lever 44 is pivoted by a lever 46 which is attached to the shaft 45 and is actuated by one of the drive parts 22, 23, ie the pivot drive part 22. The rotation drive unit 22 is a unidirectionally acting piston / cylinder drive device having a piston 47, which serves as a cylinder of the drive unit 22 and opens toward the lever 46. 36 blind holes 48 are formed. An associated flexible compressed air supply conduit 28 opens into this blind hole 48. The piston 47 presses the lever 46 directly. A preloaded reconditioning spring 49 in the form of a helical compression spring is attached on the one hand to the bearing housing 36 and on the other hand to the collar 43, which returns the pivot lever 44 and thus the collar 43 to the working position. To help.
[0014]
The rod 43 has a lower half body 50 pivotally attached to the lower end of the rotating lever 44 on the opposite side of the shaft 45 by the fork-shaped support arm 51 and the support shaft 52. At this time, the shaft 45 and the support shaft 52 are As seen in FIG. 2, one is arranged in the z direction on the other. The lower half 50 has an additional arm 53 on which a readjustment spring 49 is hung.
[0015]
The upper half 54 of the heel is pivotally attached to the lower half 50 by the heel hinge 55. Near their tips, the halves 50, 54 have cutting blades 56, 57 that are incorporated to perform cutting operations during the cutting operation. Near these cutting blades 56, 57, the saddle halves 50, 54 have thin tip portions 58, 59. A clamp spring 60 in the form of a leaf spring is arranged on the upper half 54. The clamp spring is joined to the halves 50 and 54 by a hook hinge 55. The clamp spring is not attached to the lower half 50 so as to be rotatable about the flange hinge 55. For this purpose, the clamp spring is held by a fixing pin 61 attached to the lower half 50, at which time the fixing pin passes through a well-sized hole 62 in the upper half 54 and passes through a rectangular spring clamp 60. Reach hole 63. The hole 62 in the upper half 54 is sufficiently dimensioned so that the upper half 54 can rotate to the required degree relative to the lower half 50 that is non-rotatably mounted. On its end opposite to the fixing pin 61 and directed towards the tip portions 58, 59, the clamp spring 60 has a clamp jaw 64.
[0016]
As seen in FIGS. 4, 9, 10 on the one hand and in FIG. 5 on the other hand, the upper half 54 is in two positions relative to the lower half 50: a closed position (FIG. 5) and an open position (FIG. 4, 9, 10). Closing the rod 43, i.e. rotating the upper half 54 to the closed position seen in Fig. 5, is a unidirectionally actuated piston / cylinder drive which serves as the closure drive 23. 23. The piston 65 can be displaced in the x direction in the blind hole 66 constituting the cylinder in the bearing housing 36. A flexible compressed air supply conduit 29 also opens in the blind hole 66. The piston 65 has a guide section 67 that projects beyond a blind hole 66, which is formed in the bearing housing 36 near its end that is directed away from the blind hole 66. The inside of the support 68 is guided so as to be displaceable. A stopper 69 is attached to the guide section 67 in the immediate vicinity of the blind hole 66 by a set screw 70. The stopper 69 is displaceable in the x direction, and serves to close the collar 43 by rotating the upper half 54 when the closing drive unit 23 is operated by compressed air. A preloaded compression spring is mounted in the guide section 67 between the bearing 68 and the stopper 69 and serves as a readjustment spring 71 for the piston 65 having a displaceable stopper 69. A fixed stopper 72 is screwed onto the bearing housing 36 in the y direction downstream of the displaceable stopper 69.
[0017]
The upper half 54 has an elbow arm 73 with a pin 74, and when the closing drive 23 is actuated accordingly, a stopper 69 engages with this pin 74, and the upper half 54 is shown in FIG. The heel 43 is closed by pivoting from the open position seen in FIG. 5 to the closed position seen in FIG. When the rod 43 is swung from the operating position shown in FIG. 5 to the lateral position in FIG. 4, the pin 74 comes into contact with the fixed stopper 72 , and as a result, the upper half 54 is rotated again to its open position. The
[0018]
The method of operation is as follows.
The workpiece 13 is placed on the support 12, the pressing plate 14 is lowered onto the workpiece 13 by the pressing bar 35, and then the workpiece 13 is sandwiched between the pressing plate 14 and the support 12. In this case, the needle 9 is above the holding plate 14. The thread 75 through which the needle 9 has been guided extends in the direction toward the tip portions 58 and 59 of the collar 43 which is closed and in the working position as seen in FIG. Further, as can be seen in FIG. 5, the ridge 43 is located upstream of the needle 9 (roughly outlined) (as viewed in the workpiece transport direction, which is the x direction). Therefore, the collar 43 cannot collide with the needle 9.
[0019]
When the sewing machine is started, that is, at the beginning of the overlocking operation, the first zigzag stitch 76 is made roughly outlined in FIG. As a result of the pressing plate 14 moving forward in the x direction, the workpiece 13 is also moved in the x direction. When the first zigzag stitch 76 is made, the tail piece 78 of the upper thread 75 reaching from the eye 77 of the needle 9 to the tip portions 58 and 59 of the collar 43 is sewn by the zigzag stitch 76. Since the workpiece 13 moving in the x direction also pulls the tail piece 78 in the x direction, the workpiece is surely sewn by the zigzag sewing 76. Before the tail piece 78 is completely sewn by the zigzag stitch 76, the control unit 30 triggers the pivoting drive unit 22, so that the piston 47 is pushed out of the blind hole 48, so that the collar 43 is seen in FIG. It is turned to the side position. During this rotation, the pin 74 of the upper half 54 abuts against the fixed stopper 72, and thereby the upper half 54 is simultaneously rotated to the open position in FIG. This opening action is possible because the displaceable stopper 69 is in the retracted position of FIG. FIG. 9 also shows a tail piece 78 fully sewn in between by a zigzag stitch 76. The buttonhole seam 79 is completed by making two further blocks, zigzag stitching 76 and stay stitching 80, 81, as seen in FIG. Shortly before the seam is completed, the rotation drive unit 22 is released from the pressure via the control unit 30, so that the open rod 43 is swung from the side position to the operation position by the biased readjustment spring 49. (This is shown in FIG. 10). Overlocking work can be completed during this operation. This is because the needle 9 can pass through the opening 56 a between the cutting blades 56, 57 spaced from the lower half 50 and the upper half 54. As viewed in the x direction, the cutting blade 57 is located on one side of the needle 9 and the cutting blade 56 is located on the other side of the needle 9.
[0020]
After the end of the over-stitching operation, that is, once the sewing machine is stopped, the upper thread 75 is cut by pressurization of the closing drive unit 23, whereby the upper half 54 can be seen in FIG. Move to closed position. Since the collar 43 is placed on the very thin holding plate 14 near the recess 42, the upper thread 75 is cut at a small interval of about 0.5 mm from the workpiece 13. The process of the cutting operation and the clamping operation will become clear from FIGS. FIG. 11 shows the start of the closing operation immediately after the upper thread 75 is cut, and FIG. 12 shows the closed collar 43 in which the tail piece 78 of the upper thread 75 is sandwiched between the collars.
[0021]
If another buttonhole seam 79 must be made, the tail piece 78 of the upper thread 75 is moved away from the work piece 13 by moving the work piece 13 in the x direction with respect to the needle 9. And as a result, the workpiece can be properly stitched by the first zigzag stitch 76 as described above. As a result, the tail piece is oriented in the x direction, that is, the tail piece is not displaced at all when the collar 43 is pivoted from the operating position to the side position, and the opening operation of the collar 43 is then rotated backward. Start only after the movement has started.
[Brief description of the drawings]
FIG. 1 is a rear view of a buttonhole sewing machine for overlocking a linen buttonhole.
FIG. 2 is an enlarged view of a part of the sewing machine according to an arrow II in FIG.
3 is a side view of the region seen in FIG. 2 according to arrow III in FIG.
4 is a plan view of the region seen in FIG. 3 according to arrow IV in FIG. 3, with the upper thread clamp in the first open position shown in the lateral position.
FIG. 5 is a view corresponding to FIG. 4, in which the upper thread clamping rod is in the second closed position shown in the operating position.
6 is a cross-sectional view of the region seen in FIG. 5 taken along line VI-VI of FIG. 5, rotated clockwise by 90 ° compared to FIG.
7 is a partially broken view corresponding to the arrow VII in FIG. 3; FIG.
FIG. 8 is a view partially corresponding to FIG. 7 and having a corrected position of the upper thread clamping rod.
FIG. 9 is a detail of FIG. 5 shown on an enlarged scale, with the tail piece of the upper thread sewn by the initial zigzag stitching.
FIG. 10 is a view corresponding to FIG. 9 showing the completed button hole, in which the upper thread clamping rod in the second closed position is in its operating position before the cutting operation performed by the upper thread clamping rod.
11 is a view of the upper thread clamping rod as viewed from the direction of arrow XI in FIG. 5 at the beginning of the upper thread cutting operation.
12 is a view corresponding to FIG. 11, showing a state in which the upper thread is cut and the tail piece is clamped. FIG.
[Explanation of symbols]
9 Needle 10 Hook 13 Workpiece 14 Workpiece pressure plate 15 Drive mechanism 21 for workpiece pressure plate Upper thread clamp / cutter 22 Rotation drive unit 23 Closure drive unit 33 Upper thread clamping rod 36 Bearing box 42 Recess 43 Upper thread clamping rod 49 Re-adjustment spring 50 Lower half body 54 Upper half body 55 Pivot hinge 56 Cutting blade 56a Upper thread receiving opening 57 Cutting blade 58 Tip portion 59 Tip portion 64 Clamp jaw 69 Stopper 72 Fixed stopper 75 Upper thread 78 Tail One piece 79 seam

Claims (4)

-A needle (9) that can be driven to reciprocate up and down along the travel path;
-Hook (10),
-A workpiece holding plate (14) for holding and guiding the workpiece (13) under the needle (9) during the sewing operation;
-A drive mechanism (15) for the workpiece pressing plate (14);
-Consists of an upper thread clamp and cutter (21),
The workpiece retainer plate (14) has a recess (42) through which the needle (9) passes during the production of the seam (79);
-The upper thread clamp cutter (21) has an upper thread clamp (43), and the upper thread clamp (43)
--- a lower half (50) having a cutting blade (56) in the tip portion (58);
--- an upper half (54) that pivots about the pivot hinge (55) relative to the lower half (50) and has a cutting edge (57) in the tip portion (59);
--- In order to clamp and hold the tail piece (78) of the upper thread (75), a clamp jaw (64) that can be elastically pressed to the tip part (59) of the upper half (54) is provided,
--- The upper thread clamp / cutter has an action position in which the cutting blades (56, 57) are located above the recess (42) of the workpiece pressing plate (14),
-A drive mechanism for rotating the upper half (54) relative to the lower half (50) from the first open position to the second closed position;
-A mechanism for rotating the upper thread clamping rod (43) from the operating position of the cutting blades (56, 57) to the side position beyond the recess (42),
-In the first open position, the movement path of the needle (9) extends through the upper thread (75) receiving opening (56a) formed between the cutting blades (56, 57),
-The tip (59) of the upper half (54) is also released from the clamping jaw (64) in the first open position,
-The tip portion (58, 59) at least partially overlaps in the second closed position;
-Also in the second closed position such that the tip (59) of the upper half (54) is in thread-engagement engagement with the clamping jaw (64),
In the sewing machine
The drive mechanism for rotating the upper half (54) is a closed drive (23) only for rotating the upper half (54) from the opened first position to the closed second position. Is configured as a piston / cylinder drive that acts pneumatically and acts in one direction, and engages with the upper half (54) to close the rod (43) by means of a displaceable stopper (69) A readjustment spring (71) is provided that pushes back the displaceable stopper (69) .
The drive mechanism for rotating the upper thread clamping rod is a rotation drive unit (22) only for rotating the rod (43) from the operation position to the side position, and is operated by air pressure. A fixed stopper (72) is provided, which is configured as a piston / cylinder driving device that acts in the direction, and abuts the upper half (54) when rotated from the working position to the side position, and the fixed stopper (72) Is arranged so that the upper half (54) remains in the fixed stopper when the tip (59) of the upper half (54) is released from the needle (9), and the ridge (43) A readjustment spring (49) is provided for pivoting from the lateral position to the operating position ;
A sewing machine characterized by The upper half (54) is provided with a pin (74) which abuts on the one hand on a displaceable stopper (69) and on the other hand on a fixed stopper (72). The described sewing machine. The sewing machine according to claim 1, wherein the upper thread clamping rod (33) is attached to the bearing housing (36), and the drive portions (22, 23) are formed in the bearing housing (36). 4. The sewing machine according to claim 1, wherein the piston / cylinder driving device is formed in a bearing box.

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