JPS6340555B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a cloth feed direction reversing device for a sewing machine, and more particularly to a power cloth feed direction reversing device for a sewing machine that can reverse the cloth feed direction by operating an electromagnetic solenoid for reversing the cloth feed direction. It is something.

[Conventional technology]

FIG. 7 is a partial schematic view of a power cloth feed direction reversing device of a conventional sewing machine, in which a U-shaped forked arm 2 is rotatably mounted on pivot shafts 1a and 1b on the lower surface of a bed (not shown). will be established. The bases of a pair of links 4a, 4b that support the swinging fulcrum shaft 3 are attached to the inside of the tip of the forked arm 2.
(not shown), and the swing fulcrum shaft 3 inside the pair of links 4a, 4b has a rod whose upper end is loosely fitted into the eccentric cam 7 of the upper shaft 6 which rotates in the direction of arrow B. An arm 10a is fixed to one side of a horizontal feed shaft 9 whose lower end and the other end are loosely fitted to the bottom surface of the bed.
The other end of the horizontal feed shaft 9 is provided with a feed tooth 12, and the other end supports one end of a feed bar 13 which is given vertical movement. The arm 10b is fixed. Here, the respective center distances between the rotational fulcrum shaft 1a and the movable fulcrum shaft 5a, the rotational fulcrum shaft 1b and the movable fulcrum shaft 5b of the forked arm 2, and the movable fulcrum shafts 5a, 5b of the pair of links 4a, 4b and the rocking The center distances of the fulcrum shafts 3 are the same. A lower end of a link 18 rotatably supported by a shaft 14 in an arm body (not shown) and rotatably connected to an arm 16a of a feed adjustment cam 15 having a butterfly-shaped cam 17 formed on one side is a moving fulcrum. It is rotatably connected to the shaft 5a. A threaded rod 20 equipped with a feed dial 19 is screwed onto the arm body of the feed adjustment cam 15 facing the butterfly-shaped cam 17, and its tip contacts the butterfly-shaped cam 17 to constantly urge the link 18 upward. do. in this case,
The counterclockwise rotation of the feed adjustment cam 15 about the shaft 14 by the spring 21 is restricted. A link 22 has one end rotatably connected to the feed adjustment cam 15, and the other end rotatably connected to the plunger 24 of a reversing electromagnetic solenoid 23 attached to the back of the arm body.

Reference numeral 25 denotes a manual pressing operation body whose base end is rotatably supported by the arm body from a shaft 26, and has a pressing portion 25a formed at a suitable location on the front surface of the arm.
When is pressed, normally open reverse switch 2
7 is closed, thereby energizing the reversing electromagnetic solenoid 23, electromagnetically attracting the plunger 24, and rotating the feed adjustment cam 15 clockwise about the shaft 14.

A conventional power cloth feed direction reversing device for a sewing machine is constructed as described above, and its operation will be described below. The upper part of the butterfly-shaped cam 17 of the feed adjustment cam 15, which rotates counterclockwise around the shaft 14 due to the upward pulling action of the link 18 by the spring 21, contacts the threaded rod 20, and moves via the arm 16a and the link 18 to the moving fulcrum shaft 5a. , and move the moving fulcrum shafts 5a and 5b to the link 1 as shown in the diagram of horizontal cloth feeding in Fig. 8.
1 and the connection point between arm 10a and rotation fulcrum shafts 1a and 1b
Neutral straight line A connecting the centers of each (indicated by a dashed line)
The rod 8 is locked above the extension line of the link 11 and the arm 10a by vertical movement of the swinging fulcrum shaft 3 by the eccentric cam 7 from the top dead center indicated by the two-dot chain line to the bottom dead center indicated by the solid line. , feed dog 1 via horizontal feed shaft 9
Approximately parallelogram forward and backward cloth feeding motions are applied to 2. Figure 14 is a motion diagram.The horizontal axis of the figure is a scale indicating the rotation angle of the upper shaft 6, with the highest point of the needle that reciprocates up and down in conjunction with the upper shaft 6 as 0°, and the upper vertical axis is the scale. is a graph in which a needle bar vertical curve and a feed vertical curve are drawn with the vertical movement of the needle and the feed dog 12 as a scale based on the upper surface of the throat plate. moreover,
On the lower vertical axis of FIG. 14, the amount of movement of the feed dog 12 in the forward and backward direction of cloth feeding is scaled, and a forward and backward curve for forward feed and a forward and backward curve for reverse feed are drawn. That is, the top dead center indicated by the two-dot chain line in Fig. 8 (approximately the upper axis rotation angle in Fig. 14)
300°), the feed dog 12 protrudes from the upper surface of the throat plate,
When the rod 8 is lowered by the eccentric cam 7, it pushes the swinging fulcrum shaft 3 downward, and the links 4a and 4b rotate counterclockwise around the movable fulcrum shafts 5a and 5b, as shown by the solid line. 11 and arm 1
0a, the horizontal feed shaft 9 is rotated clockwise, and the cloth is sent to the right in FIG. 7 by the feed dog 12 in FIG. The rod 8 reaches the bottom dead center (upper shaft rotation angle approximately 120° in Figure 14) by the eccentric cam 7, the feed dog 12 sinks to the lower surface of the throat plate, and the upper shaft 6 further rotates. Then, when the rod 8 is raised by the eccentric cam 7, the swing fulcrum shaft 3 is pulled upward, and the links 4a and 4b rotate clockwise about the movable fulcrum shafts 5a and 5b, via the link 11 and the arm 10a. The horizontal feed shaft 9 is rotated counterclockwise, and the feed dog 12 is moved to the left while being sunk to the lower surface of the throat plate, and the upper shaft rotation angle is approximately 120° to approximately 300° as shown in Fig. 14. The curve and rod 8 are at the top dead center due to the eccentric cam 7. Thereafter, due to the rotation of the upper shaft 6, the feed dog 12 continuously feeds the cloth in the above-mentioned direction by the combined motion of the normal feed back and forth curve and the feed up and down curve in FIG. 14.

Also, to convert the cloth feed mentioned above to the backward direction,
When the manual push operation body 25 shown in FIG. 7 is pressed, the reverse rotation switch 27 is closed, thereby energizing the reverse rotation electromagnetic solenoid 23. As a result, the shaft 1 is moved through the link 22 by the suction of the plunger 24.
4 until the lower part of the butterfly-shaped cam 17 of the feed adjustment cam 15 contacts the threaded rod 20, this rotational movement is transmitted to the moving fulcrum shaft 5a via the link 18, as shown in FIG. As shown in the diagram of horizontal cloth feeding, the movement fulcrum shafts 5a, 5b move clockwise around the rotation fulcrum shafts 1a, 1b of the forked arm 2 in a neutral straight line A.
It is locked downward beyond . The swinging fulcrum shaft 3, which is the connection point between the links 4a and 4b shown by the two-dot chain line in FIG. Shows the state at an angle of approximately 300°. In this state, as described above, the feed dog 12 shown in FIG. 7 has begun to protrude above the throat plate. From this state, the upper shaft 6 rotates and the feed dog 12 protrudes above the throat plate surface, and when the rod 8 is lowered by the eccentric cam 7, the link 11 and the arm 1
0a to rotate the horizontal feed shaft 9 counterclockwise to feed the cloth to the left (upper shaft rotation angle of approximately 300° in Fig. 14 →
When the rod 8 reaches the bottom dead center (the rotation angle of the upper shaft is approximately 120 degrees in FIG. 14), the state shown by the solid line is shown and the feed dog 12 sinks to the lower surface of the throat plate. When the upper shaft 6 further rotates and the rod 8 rises from the bottom dead center to the top dead center, the feed dog 12 moves to the upper right in FIG. The cloth is continuously fed in the backward direction by repeating the composite movement of the shaft rotation angle of about 120° → about 300° (reverse feed back and forth curve), and the reverse feed back and forth curve and the feed up and down curve in FIG. 14.

In such a conventional power cloth feeding direction reversing device, the timing at which the electromagnetic solenoid 23 is energized by the pressing operation of the manual pressing operation body 25 is arbitrary. Therefore, for example, the forward cloth feeding state shown in FIG. When the reverse rotation is performed near the top dead center of the rod 8 as shown in , and the reverse conversion is performed to the reverse state shown by the two-dot chain line, the horizontal feed shaft 9 changes from the state shown by the solid line to the reverse state shown by the solid line.
It rotates to the state shown by the dotted chain line. That is, by closing the reverse switch 27, the electromagnetic solenoid 23 is energized, and the plunger 24, link 22, and feed adjustment cam 1 are energized.
5. When the movable fulcrums 5a and 5b are rotated clockwise around the rotational fulcrum shafts 1a and 1b beyond the neutral straight line A via the links 18, the swinging fulcrum shafts which are the connecting points of the rods 8 and the links 11 3 moves to the right as shown in Fig. 10, and as a result, the horizontal feed shaft rotates clockwise to the extent of the normal cloth feed stroke (at the upper shaft rotation angle of about 300° in Fig. 14, it moves from the normal feed back and forth curve). (Move to reverse forward/backward curve). For example, when the solid line in the forward cloth feeding state in the diagram shown in FIG. rotates from the state shown by the solid line to the state shown by the two-dot chain line, and it is clear that the horizontal feed shaft 9 rotates to the extent of the normal cloth feed stroke (the upper shaft rotation angle is approximately 120° in Fig. 14). to move from the forward and backward forward feed curve to the reverse forward and backward curve.

On the other hand, if the reverse rotation is performed in the forward cloth feeding state shown by the solid line in the horizontal cloth feeding diagrams of FIGS. 12 and 13, and in a state where the swing fulcrum shaft 3 is on the neutral straight line A. (Approx.
25 degrees and an upper shaft rotation angle of about 205 degrees), as described above, the distance between the centers of the rotation fulcrum shafts 1a, 1b of the forked arm 2 and the centers of the movable fulcrum shafts 5a, 5b, and the pair of links 4a, Since the distance between the centers of the movable fulcrum shafts 5a, 5b of 4b and the center of the swing fulcrum shaft 3 is the same, the movable fulcrum shafts 5a, 5b change from the forward state shown by the solid line to the reversed state shown by the chain line, and the bifurcated arm 2, the horizontal feed shaft 9 does not swing, and the horizontal feed shaft 9, the arms 10a, 10b, the link 11, and the feed Platform 13
Since the inertia of the reversing electromagnetic solenoid 2 does not work,
The load acting on 3 is also lighter and faster.

In FIGS. 12 and 13, the center of the swing fulcrum shaft 3 and the center of the rotation fulcrum shafts 1a and 1b overlap, but are shifted in the drawings.

[Problem that the invention seeks to solve]

In the conventional power cloth feeding direction reversing device of a sewing machine as described above, reverse rotation and return to normal rotation from reverse rotation are performed at arbitrary times. There is a problem that the seam quality deteriorates, and the above-mentioned feed dog 12
If the feed dog 12 is reversed or returned to normal rotation near the top dead center or bottom dead center of the rod 8, when the rod 8 begins to protrude from the top of the throat plate or begins to sink from the top of the throat plate, the feed dog 12 will be placed above the throat plate When moving a certain piece of fabric, there are problems such as the needle breaking when it starts penetrating the fabric or coming out of the fabric.Furthermore, in needle-feed sewing machines that have an upper fabric feed device connected to the horizontal feed axis, it is difficult to move the horizontal feed axis. The inertial force of the transmission mechanism increases, which aggravates the above-mentioned problems, and many other problems arise.

This invention was made to solve this problem, and even when operated during reverse cloth feed conversion and normal cloth feed return, beautiful seams can be maintained without causing problems such as needle breakage, etc. The purpose of the present invention is to obtain a power cloth feed direction reversing device for a sewing machine that can be operated in the following manner.

[Means for solving problems]

In the power cloth feed direction reversing device for a sewing machine according to the present invention, the movable fulcrum shafts 5a and 5b are connected to the rotation fulcrum shaft 1.
a and 1b are used as fulcrums for rotational locking, and the swinging fulcrum shaft 3
swings around the movable fulcrum shafts 5a and 5b as fulcrums,
The connection point between the link 11 and the arm 10a that transmits this swinging motion to the cloth feeding motion, and the pivot shafts 1a, 1b.
It is equipped with a signal detection device 29 that generates a detection signal 29s that detects when the swing fulcrum shaft 3 passes on a neutral straight line connecting the center of The electromagnetic solenoid 23 for
a and 5b are rotationally locked in the reverse feeding direction, and then are rotationally locked in the forward feeding direction from the reverse feeding direction.

[Effect]

In this invention, the swing fulcrum shaft 3 passes on the neutral straight line in response to the reverse rotation command signal 27s by a desired operation, and the detection signal 29s generated at the time of this passage energizes the reverse electromagnetic solenoid 23 in the cloth feeding direction. Since the cloth is reversed and then deenergized to return the cloth feed direction to the normal feed direction, problems such as needle breakage and uneven stitching are eliminated.

〔Example〕

FIG. 1 is a schematic diagram of essential parts showing one embodiment of the present invention, and in the figure, numerals 7, 8, 22 to 24 are completely the same as those of the conventional device. In the figure, a detection plate 28 having a notch 28a is fixed to the rear end of the upper shaft 6, and a light emitting element 29 is mounted in the radial direction of the notch 28a and opposite to the radial position of the notch 28a.
a signal detection device 29 consisting of a light receiving element 29b;
When the light receiving element 29b is exposed to the light emitted from the light emitting element 29a, a count signal (detection signal) 29s to be input to the microcomputer 30 shown in the connection diagram of FIG. 2 is generated. Further, this signal is detected when the feed dog 12 shown in FIG. 7 is sunk below the throat plate and the swing fulcrum shaft 3 shown in FIG. 13 is located near the neutral straight line A. In addition, the microcomputer 30 shown in FIG.
(hereinafter referred to as MCU) is provided with a reverse rotation switch 27 for inputting a reverse rotation command signal 27s. The other mechanical configurations are the same as those of the conventional example, so their explanation will be omitted.In FIG. 2, 23 is the reversing electromagnetic solenoid shown in FIG. 1, and 27s is the manual push operation body 2 shown in FIG.
5 is operated and input into the MCU 30, 31, 32, 33 are low resistors, 34 is a transistor, 35 is a diode, and 36 is a varistor. The time constants of the resistor 3 and the diode 35 are determined according to the mechanical characteristics of the reversing electromagnetic solenoid 23. Reference numeral 37 denotes a reverse stitch number setting device for presetting the number of stitches in which the cloth feeding direction is reversed to a required value (N).

FIG. 3 shows a flowchart of a program stored in a storage device (not shown) within the MCU 25. Next, the contents of each step in FIG. 3 will be explained. In the figure, TBF at step 40
(Touch Back Flag MCU calculation start flag) is a flag for storing the input of the reverse rotation command signal 27 in the MCU 30. Reverse command signal 27
If no input is made, that is, at step 41n in step 41, the MCU 30 moves to other processing 51 without processing the reversing electromagnetic solenoid 23, as shown in FIG. Now, reverse command signal 27
When s is input, TBF is set to 1 [step 42] and the set count number (N) is set.
Counting RAM area in MCU30 (not shown)
Store it in M [step 43]. Next, it is determined whether M=0 (step 44). M≠0
In the case of 44N, the transistor 34 is turned on using the rise of the count signal 29s [step 45].
and subtract 1 from M with [step 47],
The result is stored again (step 46). After that, when the process moves to another process 51 and returns to the process shown in FIG. 3, since TBF=1 (40Y), it is immediately determined whether M=0
4]. If M≠0, repeat the same operation as above, and if M=0, 44Y will turn off the transistor 34 in synchronization with the count signal 29s, so M=0 until the count signal 29s turns on.
Even so, the reversing electromagnetic solenoid is turned on. In this state, the count signal 29s is ON
Then, the transistor 34 is turned off [step 49 and TBF is set to 0 [step 50]]
to return to the initial state. FIG. 4 shows a timing chart when N=3 is set.

The mechanical operation will be explained with respect to the operation according to the flow shown in FIG. 3 described above. When the reversal command signal 27s due to the pressing operation of the manual pressing operation body 2 is input to the MCU 30, a signal indicating that the swing fulcrum shaft 3 is attached to the upper shaft near the neutral straight line A as shown in FIGS. The MCU 30 is activated by the signal from the detection device 29.
is output to make the transistor 34 conductive, thereby energizing the reversing electromagnetic solenoid 23 and reversing the cloth feeding direction. After the preset number N of reverse stitches is counted by the signal detection device 29, a signal from the signal detection device 29 attached to the upper shaft is detected when the swing fulcrum shaft 3 shown in FIG. MCU by count signal 29s
30 outputs an output to shut off the transistor 34, thereby deenergizing the reverse electromagnetic solenoid 23 and returning the cloth feeding direction to the normal feeding direction.

In addition, in the above embodiments, all of the feeding mechanisms are shown as having link configurations with rotating pairs, but the fifth embodiment
As shown in FIG. 6, the rod 8 is loosely fitted into the eccentric cam 7 in a forked shape, and the forked arm 2 and the feed adjustment cam 15 are connected to each other.
It is clear that a configuration in which the is a single component is also acceptable. FIG. 5 is a diagram showing the forward cloth feeding state, and FIG. 6 is a diagram showing the backward cloth feeding state in FIG.

〔Effect of the invention〕

As explained above, in this invention, the reverse rotation direction change and forward rotation return conversion of the feed dog 12 are performed when the swing fulcrum shaft 3 is near the neutral line A and the feed dog 12 is submerged from the throat plate surface. I did it like this,
Problems such as needle breakage and uneven seams due to the inertia of the cloth to be sewn are eliminated, and it is also possible to feed the cloth in cooperation with the feed dog 12 by connecting it to a sewing machine that feeds a large amount of cloth or a horizontal feed shaft. This has the advantage that it can be applied to sewing machines that have an upward cloth feeding device that performs this process and have large inertia of the feed dog and horizontal feed shaft, such as needle feed sewing machines.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing essential parts of a mechanism according to an embodiment of the present invention, and FIG. 2 is a connection diagram showing an example of an electric circuit that drives the electromagnetic solenoid for reversing shown in FIG. 1.
Figure 3 is a flowchart showing the flow of the MPU in Figure 2, Figure 4 is a timing chart showing the timing of signals handled by the electric circuit in Figure 2,
5 and 6 are diagrams showing horizontal cloth feeding in another embodiment of the present invention, FIG. 7 is a schematic diagram showing the main parts of a power cloth feeding direction reversing device of a conventional sewing machine, and FIG. 8 is a line diagram showing the forward state in horizontal cloth feeding in Fig. 7, Fig. 9 is a line diagram showing the backward state in horizontal fabric feeding in Fig. 7, and Fig. 10 is a diagram showing the top dead center in horizontal fabric feeding in Fig. 7. 11 is a line diagram showing a state in which the cloth feeding direction is reversed at the bottom dead center in the horizontal cloth feeding shown in FIG. 7, and FIGS. FIG. 7 is a diagram showing a state where the cloth feeding direction is reversed at the neutral point in horizontal cloth feeding, and FIG. 14 is a motion diagram of FIG. 7. In the figure, 1a and 1b are rotary fulcrum shafts, 3 is a swing fulcrum shaft, 5a and 5b are movable fulcrum shafts, 7 is an eccentric cam, 8 is a rod, 9 is a horizontal feed shaft, 10a is an arm,
11 is a link, 23 is a reversing electromagnetic solenoid, 2
7s is a reverse command signal, 29 is a signal detection device, 29
s is a count signal (detection signal). Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A movable fulcrum shaft that is rotatably locked in the forward feed direction or reverse feed direction using the rotating fulcrum shaft as a fulcrum, and a swing fulcrum shaft that swings up and down using an eccentric cam and rod using the movable fulcrum shaft as a fulcrum. Then, the swing fulcrum shaft runs on a neutral straight line connecting the center of the swing fulcrum shaft and the connection point between the arm and the link that transmits the vertical swing motion of the swing fulcrum shaft to the cloth feeding movement of the horizontal feed shaft. a signal detection device that generates a detection signal when the object passes, a reverse rotation command signal that is operated when desired, and a detection signal generated from the signal detection device to rotationally lock the moving fulcrum shaft in the reverse feed direction. A power fabric feed direction reversing device for a sewing machine, comprising a reversing electromagnetic solenoid that later locks the reverse rotation from the reverse feed direction to the forward feed direction in response to the detection signal.