JPS6311192A - Cloth presser of sewing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Purpose of the Invention (Industrial Field of Application) This invention provides a method for processing cloth with a work cloth held in a work cloth holder.
In a sewing machine that performs sewing while relatively moving the needle across an R descent path, a presser foot is raised and lowered in synchronization with the raising and lowering of the needle to prevent work cloth from rising on a work cloth holder. This invention relates to a presser foot device.

(Prior art) As a conventional device of this kind, for example,
A configuration as shown in Japanese Patent No. 386 is known. In this device, a swinging cam is supported on the sewing machine arm so as to be able to swing around a fixed axis, and when the swinging cam swings as the needle moves up and down, the cam action causes the driven pin on the presser bar to move. The presser foot is raised and lowered through the presser foot.

(Problem to be Solved by the Invention) However, in this conventional cloth presser, when the thickness of the work cloth changes during sewing, for example when the thickness increases, the swing stroke of the swing cam is not constant. Despite this, the working position of the presser foot is restricted to a high position due to contact with the work cloth, so the driven pin on the presser foot lifts up from the cam part of the swing cam, causing the presser foot to move against the presser foot. The spring pressure of the spring circulates through the work cloth, and the work cloth is compressed more strongly than before as the thickness of the work cloth increases, and the thread passing through the work cloth increases and thread tightness worsens. There was a problem.

Structure of the Invention (Means for Solving the Problems) The present invention has been made by paying attention to the above-mentioned problems. a needle bar, a work cloth holder that holds the work cloth on a work cloth support surface and moves the work cloth relative to the needle across the lifting path thereof, and prevents the work cloth from rising on the work cloth holder. A presser foot is used to process the workpiece cloth while the needle is penetrating the workpiece cloth in synchronization with the raising and lowering of the needle, and the presser foot is raised during other times. an actuating means for operating the presser foot with a constant operating stroke so as to cause the presser foot to move, a switching means for acting on the operating means and displacing the operating stroke area of the presser foot; control means for controlling the operation of the switching means based on information regarding the thickness of the switching means.

(Function) Therefore, in the presser foot device of the sewing machine of the present invention, when the thickness of the fabric to be processed changes, the switching means is operated according to the thickness, and the operating stroke area of the presser foot by the actuating means changes. A constant spring pressure is always applied to the fabric to be processed regardless of changes in the fabric, making it possible to form stitches with good thread tightness.

(Embodiment) Hereinafter, a first embodiment of a presser foot device for a sewing machine embodying the present invention will be described with reference to FIGS. 1 to 3.

As shown in FIG. 1, a sewing machine frame 1 includes a sewing machine bed 2 and a sewing machine arm 3. A needle plate 4 having a needle hole 4a is mounted on the sewing machine bed 2, and a work cloth support surface 5 is formed on the upper surface of the needle plate 4 and the sewing machine bed 2. A work cloth holder 6 for holding the work cloth W is disposed on the work cloth support surface 5, and a feed plate 7 in the shape of a rectangular frame is disposed on the work cloth support surface 5.
and a presser plate 8. Then, the work cloth holder 6 is driven by the X-direction and Y-direction movement motors 9 and 10 shown in FIG. 3 based on predetermined sewing data.
A feed motion in the lateral direction is applied to the work cloth W through the work cloth W.

On the other hand, a needle bar 11 is supported on the sewing machine arm 3 so as to be movable up and down, and a needle 12 is attached to the lower end of the needle bar 11. A needle bar holder 13 and an operating arm 14 are fixed to the needle bar 11.
A bottle 14a is protruded from the front of the operating arm 14. As the sewing machine main shaft rotates based on the drive of the sewing machine motor 15 shown in FIG. The work cloth W on the work cloth holder 6 (
,: A seam is formed.

A presser foot 16 is movably supported on the sewing machine arm 3 so as to extend parallel to and at a predetermined distance from the needle bar 11, and a presser foot 1 has a needle insertion hole 17a at its lower end.
7 is installed. There is a presser spring 18 on the presser bar 16.
is provided to press and urge the presser foot 17 downward. When the presser foot 16 is processed, the presser foot 17 is placed on the workpiece cloth W, and the needle 12 is placed on the workpiece cloth W.
It is designed to prevent the work cloth W from lifting up when it is drawn upward from the top.

A support rod 19 is movably supported on the sewing machine arm 3 so as to be movable up and down so as to be located on the opposite side of the needle bar 11 with the presser bar 16 interposed therebetween, and a support member 2° is attached to the lower end of the support rod 19. A sliding cam 21 constituting an operating means is swingably supported at the base end of the support member 20 by a stepped screw 22, and a two-pronged portion 21a that engages with the pin 14a of the operating arm 14 is provided at its free end. is formed. A substantially arc-shaped cam portion 21b is formed in the center of the swing cam 21, and the radius from the swing center of the swing cam 21 gradually decreases from one end to the other end.

A presser bar holder 23 is fixed on the presser bar 11, and a projecting piece 23a is protruded from the negative side of the presser bar holder 23 for slidingly contacting the regulating portion 24 of the sewing machine arm 3 and regulating the rotation of the presser bar 11. At the same time, a cam follower 25 that engages with the cam portion 21b of the swing cam 21 is rotatably supported at the front portion. When the swing cam 21 swings via the bin 14a and the forked part 21a as the needle bar 11 moves up and down, the presser bar 16 moves up and down with the cam follower 25 in between by the cam action of the cam part 21b. The presser foot 17 at the lower end is operated with a constant operating stroke, and while the needle 12 is penetrating the workpiece cloth W, the presser foot 17 is lowered onto the workpiece cloth W, and at other times. During this period, the presser foot 17 is raised.

A bracket 26 is attached to the upper part of one side of the sewing machine arm 3, and a cylinder 27 constituting a switching means is attached to the side of the bracket 26.
is supported. On the bracket 26 is a rotating lever 2.
8 is rotatably supported at the center, and the piston rod 27a of the cylinder 27 and the support rod 1 are attached to both ends of the cylinder 27.
9 are connected to each other. A pair of stopper screws 29 and 30 are disposed on the bracket 26 so as to be vertically adjustable through the mounting plate 31, and are selectively engaged with both ends of the rotary lever 28 to prevent the piston rod 27a from falling. The hegemony is regulated to a certain extent. When the piston rod 27a of the cylinder 27 is retracted, the rotating lever 28
The support rod 19 is lifted up via the chain line in FIG. It has become.

Next, the control circuit of the sewing machine configured as described above is connected to the third
To explain according to the diagram, the central processing unit (CPU) 41 constituting the control means has a read-only memory (ROM).
42 and random access memory (RAM) 43 are connected. The ROM 42 stores programs for controlling the overall operation of the sewing machine, and the RAM 43 stores sewing data including count data, feed amount data, and weight change data of the work cloth W.

An operation panel 44 having various switches etc. is connected to the CPU 41 via an input interface 45,
Various signals from the operation panel 44 are input to the CPU 41. The CPU 41 also has the sewing machine motor 15,
, the Y-direction movement motor 9.10 and the presser foot displacement cylinder 27 are connected to the output interface 46 and the drive circuit 47.
50, and drive and stop signals are output from the CPU 41 to them.

Next, the operation of the sewing machine configured as described above will be explained.

Now, in this sewing machine, when the workpiece cloth W is attached to the workpiece cloth holder 6 and the sewing machine starts operating based on predetermined sewing data stored in the RAM 43, the rotation of the sewing machine main shaft due to the drive of the sewing machine motor 15 starts. The accompanying needle bar 11 is located above and below as shown in Fig. 2! Ill be raised and lowered in range R, and bin 14
The swing cam 21 swings through the forked portion 21a and the forked portion 21a,
Due to the cam action of the cam portion 21b, the cam follower 25 is moved up and down with the operating stroke S1 in the figure, and the presser foot 16 is raised and lowered. Therefore, as the needle bar 11 moves up and down, the needle 12
The workpiece cloth W on the workpiece cloth holder 6 is
A seam is formed on the workpiece cloth W, and as the presser foot 16 descends, the presser foot 17 is placed on the workpiece cloth W to prevent the workpiece cloth from lifting up.

Based on the sewing data, the workpiece cloth W on the workpiece cloth holder 6 is driven by the motors 9 and 10 for moving in the X and Y directions.
A lateral feed motion is applied to the cylinder 27 to form a stitch with a predetermined number of stitches, and when the pressure change (increase) data in the N''JJ monitor is input to the CPU 41, a drive signal is output from the CPU 41 to the cylinder 27. 2, the piston rod 27a is retracted, and the pivoting center of the pivoting cam 21 is raised by a predetermined 1L as shown in FIG.
will be increased by the amount. As a result, as the needle bar 11 moves up and down, the swing cam 21 swings at a higher position than in the above case, and the cam follower 25 moves upwardly from the operating stroke S1 in the region where the operating stroke S2 It moves up and down.

Therefore, the presser foot 17 is raised and lowered at a position raised by the increase in the right bank of the workpiece cloth W.
The thickened portion is strongly compressed by the pressing force of the presser foot 17 based on the pressing spring 18, and a seam with good thread tightness can be formed without increasing the resistance to the Japanese line passing through the work cloth W.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5.

Now, in this second embodiment, as shown in FIG. 4, a pulse motor 36 is provided on the bracket 26 as a switching means in place of the cylinder 27 of the first embodiment, and the rotation of this motor is controlled by the pinion 37. This is transmitted to the rotating lever 28 via the rack gap 38, so that the height position of the center of swing of the swing cam 21 is changed in 11,000 or more steps. Further, as shown in FIG. 5, a heavy thickness detector 51 made of photoelectric blocking or the like is connected to the input interface 45 of the CPU 41, and the right bank of the work cloth W is detected by this heavy thickness detector 51 during the sewing operation. The detection signal is c'p U 4
i is input. Furthermore, the pulse motor 36 is connected to the output interface 46 of the CPU 41 via a drive circuit 52.
A drive signal corresponding to the heavy weight detection data from the heavy weight detector 51 is outputted to the heavy weight detector 51 .

Therefore, in this second embodiment, during sewing operation of the sewing machine, the right bank of the workpiece cloth W is detected by the weight detector 51,
The pulse motor 36 is rotationally driven based on the detected data, and the swing center of the swing cam 21 is moved. For this purpose, the operating stroke area of the presser foot 17 is displaced to any height position according to changes in the thickness of the workpiece cloth W, and a constant presser pressure is always applied regardless of changes in the thickness of the work cloth W, thereby preventing thread tightening. Can form good seams.

Next, a modification of the second embodiment will be explained based on FIG. 6. In this modification, the presser foot 17 is lowered onto the workpiece cloth to create presser foot position data for the workpiece cloth W, and the presser foot lowering position of the presser foot 17 is set based on the data. That is, the flowchart shown in FIG.
It is stored in the OM 42 and the operation panel 44
When the upper setting key (not shown) is turned on, the CPU
41 determines it in step S1, and in step S
2, set the data creation mode. Next CPU4
The pulse motor 36 is driven in the direction of lowering the inner flap 7, and the presser foot 17 is lowered. When the presser foot 17 presses the work cloth W on the work cloth support surface 5 and the pulse motor 36 is out of step, the CPU 41 starts counting by a timer in the CPU 41 in step S4 and step $5. If this step-out state continues for a predetermined period of time, the CP
U41 stops the driving of the pulse motor 36 in step S7 via step S6, and also stops the driving of the pulse motor 36 in step S7.
At step 8, the data on the adjustment position of the pulse motor 36 is stored in a predetermined area of the RAM 43 as the presser foot position for the workpiece cloth W, and the pulse motor 36 is reversed to return the presser foot 13 upward.

Next, in steps S9 and S10 in the CPU 41, the program waits for the end key (not shown) in the operation panel 44 or the setting key to be turned on, and if the end key is turned on, this program ends. Also, when the setting key is turned on, the program returns to step S1.
Proceed to 1. The program after step S11 is a program for creating presser foot lowering position data corresponding to another work cloth W when another work cloth W is laminated on the work cloth W.

That is, the CPU 41 first determines in step 811 that the work cloth holder 6 has been fed so that the stacked work cloths W and the presser foot 17 face each other. Thereafter, the operator operates a manual key (not shown) on the operation panel 44 to manually rotate the pulse motor 36 and lower the presser foot 17. After the presser foot 17 reaches the position where it presses the work cloth W, if the operator turns on the end key, the CPU 41 goes through step 313 and step S14, and in step 815 sets the second presser foot based on the tax adjustment point. The foot lowering position data is stored in the RAM 42, and the pulse motor 36 is rotated in the opposite direction to raise the presser foot 17, and the program ends. Further, if the setting key is turned on instead of the end key, the CPLJ 41 stores the descending position data in step 816 in the same manner as above, and
The presser foot 17 is raised and returned to its original position, and then the process returns to step 811, where it is possible to create lowering position data for yet another workpiece cloth.

Therefore, during normal sewing, an appropriate presser foot pressure can be obtained based on the lowering position data of the presser foot 17 stored in the RAM 43, and the heavy weight detector 51 becomes unnecessary.

It should be noted that the present invention is not limited to the configuration of the above-mentioned embodiment, but can be modified and embodied as follows.

(1) In the first embodiment shown in FIGS. 1 to 3, a heavy thickness detector is provided, and the presser foot displacement cylinder 27 is configured to operate based on the detection data of the heavy thickness detector.

(2) In the second embodiment shown in FIGS. 4 and 5, the top dead center of the presser foot is set as the origin, the presser foot machining amount data from the origin is set in accordance with Ichihara, and based on the To shift the vertical position of the presser foot 17.

Effects of the Invention As detailed above, in the present invention, when the thickness of the workpiece cloth changes, the switching means is operated according to the layer of the cloth, and the range of the operating stroke of the presser foot by the actuating means is changed. This provides an excellent effect in that a constant spring thickness is always applied to the work cloth regardless of changes in the fabric layers, and seams with good thread tightness can be formed.

[Brief explanation of the drawing]

FIG. 1 is a partial front sectional view showing a first embodiment of a sewing machine embodying the present invention, FIG. 2 is a partially enlarged front view for explaining its operation, and FIG. 3 is a block diagram of a control circuit. FIG. 4 is a partial front view showing a second embodiment of the invention, FIG. 5 is a block diagram of its control circuit, and FIG. 6 is a flowchart showing a modification of the second embodiment. 2... Sewing machine bed, 3... Sewing machine arm, 5...
- Work cloth support surface, 6... Work cloth holder, 11... Needle bar, 12... Needle, 17... Presser foot, 19... Support rod, 21... Operating means Swinging cam, 27.
. . . A cylinder that constitutes a switching means, 36 . . . a pulse motor that constitutes a switching means, 41 . . . a CPU that constitutes a control means.

Claims (1)

[Claims] 1. A needle bar (11) which is supported in a vertically movable manner on a sewing machine arm (3) and has a needle (12) attached to its lower end; W) is held;
a work cloth holder (6) that moves relative to the needle (12) across its lifting path; and the work cloth holder (6).
A presser foot (17) is used to prevent the upper work cloth (W) from lifting up, and the needle (12) is moved in synchronization with the lifting and lowering of the needle (12).
) is penetrating the work cloth (W), the presser foot (1
7) on the work cloth (W), and for other times, operating means for operating the presser foot (17) with a constant operating stroke so as to raise the presser foot (17). (21), switching means (27) and (36) for acting on the operating means (21) and displacing the operating stroke area of the presser foot (17), and the thickness of the work cloth (W). control means (41) for controlling the operation of the switching means (27) and (36) based on information about the switching means (27) and (36);
) and a sewing machine presser foot device.