JPS6111634B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an overlock sewing machine with a loop-cutting device, in which the leading edge of the fabric at the start of sewing slopes upward to the left. Automatically temporarily stagnates a portion of the fabric so as not to cause damage to the fabric, and after completing the ring cutting operation, releases the stagnation of the fabric,
This invention relates to a device that allows sewing to be performed without any trouble.

Conventionally, when starting sewing during the sewing process using an overlock sewing machine equipped with a ring cutting device, if the front edge of the fabric slopes upward to the left in the direction of travel, the slope is The upper scalpel descended and came into contact with the front edge slope part a of the cloth to cut the ring from the cloth, and there was a risk of damaging the front edge slope part a.

Incidentally, Japanese Patent Application Laid-Open No. 56-85388 also discloses the invention, but the invention is based on the following: ``At the start of sewing, the end thread of the needle thread is cut on the fabric surface under the presser foot so as not to produce residual thread. It does not have the function and effect of ``preventing the fabric from coming into contact with the scalpel and causing damage when cutting the kara ring.'' Furthermore, Japanese Patent Application Laid-Open No. 56-28791 discloses a method in which ``fabric feed thread trimming is performed by electronic means'' and ``to prevent damage to the fabric due to contact of the ring-cutting scalpel with the fabric.'' It does not have the effect of "preventing".

However, in the present invention, a predetermined period of time during which the front edge inclined part a of the fabric at the beginning of sewing approaches the ring cutting knife is detected, and the blocking member is actuated in response to a command from the detection part, so that the inclined front edge part The progress of the dough is partially blocked using a dough advance prevention member, and the inclined front edge a of the dough is prevented from coming into contact with the upper knife even when the upper knife is lowered. It is highly effective because it does not cause damage to the inclined front edge a of the fabric.

Reference will now be made in detail to the accompanying drawings, which illustrate one example of carrying out the invention. Reference numeral 1 denotes a knife for cutting rings, and as is well known, a shaft rod 3 is fixed to the base end of the upper knife 1 so as to engage and rotate with the lower knife 2. As shown in FIG. Pivot support, upper knife stand 4 and shaft 3
An upper knife pushing spring 6 is interposed between the upper knife 1 and the collar 5 fixed to the collar 5, and the upper knife 1 is pressed against the protrusion 7 of the lower knife 2. A device (not shown) that rotates and swings the shaft 3 to lower the tip of the upper knife 1 and raise the tip of the upper knife 1 by the elasticity of a return spring (not shown) installed in the device. It is. Reference numeral 9 denotes a light-receiving element made of a phototransistor that is installed through the cloth sliding plate 11 on the side of the needle drop 10 at a position slightly in front of the ring-cutting knives 1 and 2, and is attached to the light-receiving element mounting plate 12 on the bottom surface of the cloth sliding plate 11. It is something to do. Reference numeral 13 denotes a light-emitting element consisting of an infrared LED installed directly above the light-receiving element 9, which is attached to a light-emitting element mounting plate 15 fixed to the head 14 of the sewing machine body, and together with the light-receiving element 9 constitutes a fabric detector 16. It is something to do. Reference numeral 17 denotes a fabric advance prevention member installed at a slight interval in front of the light receiving element 9 on the side of the needle droplet 10, as shown in FIG.
Upper and lower bearings 1 fixed respectively to the sewing machine body on the lower side
Fabric edge stop rod 20 slidably supported on 8 and 19
It is raised and lowered through the through hole 21 of the cloth sliding plate 11, and temporarily prevents the left upward slope a of the front edge of the cloth from proceeding from there to the ring cutting knives 1 and 2. 22 is a sewing machine receiving plate 2 on which the sewing machine is installed.
3 is a rotary solenoid for raising and lowering the dough stop rod 20 attached to the lower surface with a mounting base 24 fixed thereto; 25 is a solenoid arm whose base end is fixed to the rotating shaft 26 of the rotary solenoid 22; Reference numeral 27 denotes an elongated hole bored at the tip of the solenoid arm 25. A pin 28 provided at the tip of the fabric edge stop rod 20 is inserted into the elongated hole 27. Rotary solenoid 2 is activated by the transmitted signal.
The rotation shaft 26 of No. 2 is rotated by the stop rod 2.
This is converted into a linear motion of zero, and the fabric stopping rod 20 is moved up and down through the through hole 21 of the fabric sliding plate 11 as shown in FIG. Reference numerals 29 and 30 indicate stop bar restriction collars fixed to the fabric end stop bars 20 at the upper and lower portions of the lower bearing 19, which allow the stop bars 20 to protrude appropriately onto the upper surface of the cloth sliding plate 11 and sufficiently extend to the lower surface of the cloth sliding plate 11. This is to adjust the burial. 31 is a fabric stopping rod 20 between the upper bearing 18 and the upper restriction collar 29;
A stop bar return spring interposed in the stop bar 20
When the lifting solenoid 22 turns OFF,
The stop bar 20 is buried in the lower surface of the cloth sliding plate 11. 32 is a pulse generator that generates one pulse for each rotation of the sewing machine (that is, for each stitch); a magnet 35 is embedded in the side periphery of a disc 34 fixed to the main shaft 33, and a magnet 35 is placed opposite the disc 34; The device comprises a magnetically sensitive element 38 attached to a sewing machine body receiving shelf 36 via an element mounting base 37. Next, the control circuit will be explained in detail. 3
9 is a comparator, which compares the voltage of a volume 40 for comparison level adjustment connected in series with the light receiving element 9 between the power supply Vcc and ground with a preset voltage, and the output of the comparator 39 is used for fabric detection. The device 16 detects the fabric (the fabric covers the light receiving element 9 and blocks the light from the light emitting element 13)
The volume 40 is adjusted so that it becomes 0 when the fabric is detected, and becomes 1 when the fabric is not detected (light from the light emitting element 13 reaches the light receiving element 9). 4
2, 43, 44, and 45 are branch lines from which the output of the comparator 39 is branched via an inverter 41. 46 is a 3-input NAND gate 47 and 2 inputs
A flip-flop is constructed by combining NAND gates 48 as shown in FIG. A two-input NAND gate 51 which is connected to the branch line 42 and whose other input pins are connected to the branch line 43 via the CR integration circuit 50.
A falling one-pulse circuit 55 consisting of the following is connected. 52 is a flip-flop similar to the above, the input J pin is connected to the branch line 44, the input K pin is connected to the branch line 45, and the other input pins are sequentially connected to the inverter 53 and the same integration circuit 50 as above. 2 inputs connected to branch line 45 via
It is connected to the output of the same one-pulse circuit 55' made up of the NAND gate 54. 56 is a front counter consisting of a presettable counter, with the clear pin CLR set to 0 and the load pin
A two-input NAND in which LOAD is connected to the output pin of the flip-flop 52, the clock up pin CK/UP is set to 1, and the output pin of the flip-flop 52 and the output terminal of the pulse generator 16 are connected to the clock down pin CK/DW. The output of the gate 57 is connected via an inverter 58. The A, B, C, and D pins of the front counter 56 are data input pins, and the stitch number determination switch 59
In advance, set the load pin LOAD to 0 to calculate the number of stitches from when the leading edge of the fabric begins to pass through the fabric detector 16 until it reaches just before the upper and lower knives 1 and 2 (from the loop thread cutting position).
It is preset as follows. 60 connects the output pin of flip-flop 52 and the base;
This is a transistor in which the rotary solenoid 22 is connected to the collector and the emitter is grounded. 61 is a rear counter consisting of a presettable counter similar to the above, and the load pin LOAD is connected to the output pin of the flip-flop 46;
The output of a two-input NAND gate 62, in which the output pin of the flip-flop 46 and the output terminal of the pulse generator 16 are connected to the clock down pin CK/DW, is connected via an inverter 63, and the data input pins A, B, The number of stitches from C and D is set by the load pin from the moment when the trailing edge of the fabric passes the fabric detector 16 until it slightly passes the upper and lower knives 1 and 2 (from the loop thread cutting position).
This is to preset LOAD to 0. 6
5 is a 2-input OR gate (2-input
NAND gate). 66 is a monostable multivibrator, and its output operation input pin B
The output pins of the two negative input OR gates 65 are connected to each other. 67 is a transistor whose base is connected to the output Q pin of the monostable multivibrator 66, whose collector is connected to the thread trimming solenoid 8, and whose emitter is grounded. The output pins of the multivibrator 66 are connected to the C _p input pins of the flip-flops 46 and 52, respectively.

In the present invention, with the above-described configuration, when the pedal is pressed and the overlock sewing machine rotates, the fabric advances, and at the same time, a ring is generated at the leading edge of the fabric. When the leading edge covers the light-receiving element 9 of the fabric detector 16, light is received. The light from the light emitting element 13 does not reach the element 9, the output of the comparator 39 becomes 0, the output of the inverter 41 becomes 1, the output of the inverter 49 becomes 0, and the input J pin of the flip-flop 46 becomes 0 and the input K 2 pin inputs
It becomes 1 through the NAND gate 51, the output pin of the flip-flop 46 becomes 0, and the rear counter 61 does not perform a counting operation (BO=1), and the pulse from the pulse generator 32 is not input to the rear counter 61. At the same time, the input J pin of flip-flop 52 is 1, and the input K pin is connected to inverter 41.
At the same time as becomes 1, a pulse with an output of 0 is input from the one-pulse circuit 55', and the flip-flop 52
The output pin becomes 1, and the fabric progress prevention member 17
Dough stopping rod 20 Lifting rotary solenoid 2
2 is turned ON, the dough stop rod 20 projects to the upper surface of the cloth sliding plate 11 against the elasticity of the stop rod return spring 31, and prevents the advance of the left-upward inclined portion a of the front edge of the dough. At the same time, the load pin LOAD of the front counter 56 becomes 1, and the pulse from the pulse generator 32 is sent to the CK/DW pin of the 2-input NAND gate 5.
7. Enter the number of stitches input via the inverter 58 and preset by the stitch number determination switch 59 (i.e., the number of stitches from when the leading edge of the fabric begins to pass the fabric detector 16 until it reaches the loop thread cutting position). It's something to count. During the count, the fabric stopping rod 20 continues to block the progress of the inclined portion a, and when the counter 56 counts up, the front edge of the fabric comes to the empty ring yarn cutting position, and the borrow pin BO of the counter 56 reaches 0. Therefore, the output of the 2-input OR gate 65 becomes 1, and when this output changes from 0 to 1, the monostable multivibrator 66 turns ON, and its output Q is determined by the volume 68 and the capacitor 69. A pulse with a pulse width of
After the upper and lower knives 1 and 2 are engaged, the ring thread is cut. During the count, the fabric stopping rod 20 continues to block the progress of the inclined part a, so that the upper knife 1 does not come into contact with the inclined part a when cutting the loop yarn, as in the conventional case. There is no risk of cutting into the sloped portion a and ruining the product. At this time, when the pulse generated from the output pin is input to the input C _p pin of the flip-flop 52, the output pin of the flip-flop 52 is inverted to 0, the load pin LOAD of the front counter 56 becomes 0, and the pulse from the pulse generator 32 is inverted to 0. The count is stopped because it is not input to the clock down pin CK/DW, and the borrow output pin BO becomes 1 again.
At the same time, rotary solenoid 22 is turned off.
The fabric stopping rod 20 then descends to the lower surface of the fabric sliding plate 11 due to the elasticity of the return spring 31 and is buried therein. As a result, the fabric at the inclined portion a whose progress was blocked by the fabric stopping rod 20 returns to its normal state, and overlock sewing continues. Next, as the sewing approaches the end, the trailing edge of the fabric passes through the fabric detector 16 and the light from the light emitting element 13 reaches the light receiving element 9.
The output of the comparator 39 becomes 1, and contrary to the above, the output of the flip-flop 46 becomes 1, the output of the flip-flop 52 becomes 0, the front counter 56 does not operate (BO=1), and the load pin of the rear counter 61 becomes 0.
LOAD becomes 1, and the pulse from the pulse generator 32 is input to the NAND gate 62 and the inverter 63.
The number of stitches (the number of stitches from the moment the trailing edge of the fabric passes the fabric detector 16 until it slightly passes the loop thread cutting position) is input to the clock-down input pin CK/DW via the ) is counted. The counter 6
When 1 counts up, the trailing edge of the fabric comes to the ring thread cutting position from behind, and the borrow pin BO of the counter 61 becomes 0, so 2 negative input OR gate 65
The output changes from 0 to 1, the same pulse as above is generated from the monostable multivibrator 66 at this up edge, the thread trimming solenoid 8 connected to the output Q pin turns on, and the upper knife 1 engages with the lower knife 2. Then, the loop yarn is cut neatly just before the trailing edge of the fabric. At this time, the monostable multivibrator 6 is connected to the _Cp input pin of the flip-flop 46.
A pulse is input from the output pin of the flip-flop 61, and the output pin of the flip-flop 46 is inverted to 0 at the top edge of the pulse, and the counting operation of the rear counter 61 is stopped (BO=1), and the time chart of the operation is as follows. As shown in Figure 6. Note that 70 is a tip opening of a thread waste suction pipe 71 provided immediately after the upper and lower knives 1 and 2, which sucks and discards the cut thread.

[Brief explanation of the drawing]

The attached drawings show an example of carrying out the present invention, and FIG. 1 is a perspective view of the main part of an overlock sewing machine equipped with the device of the present invention, and FIG. 2 is a partial cross-sectional view of the main part of a material advance prevention member. A side view, FIG. 3 is a plan view of the main part showing the point at which the leading edge of the fabric is blocked by the fabric advance prevention member and the ring yarn is cut, FIG. 4 is a perspective view of the main part of the pulse generator, and FIG. 5 Figure 6 is a block wiring diagram of the control circuit for the operation of the solenoid for thread trimming and for raising and lowering the fabric stop bar, Figure 6 is a time chart showing the operation sequence of each part in Figure 5, and Figure 7 is a diagram of fabric in a conventional overlock sewing machine. FIG. 7 is a plan view of a main part showing a state in which the leading edge inclined portion is damaged by the upper knife. 1...Upper knife, 2...Lower knife, 3...Shaft rod, 4
...Upper knife stand, 5...Collar, 6...Upper knife push spring, 7...Protrusion, 8...Thread trimming solenoid, 9...Light receiving element, 10...Needle drop, 11...
Cloth sliding plate, 12... Light receiving element mounting plate, 13... Light emitting element, 14... Head, 15... Light emitting element mounting plate, 16... Fabric detector, 17... Fabric blocking member, 18, 19... ...Bearing, 20...Dough stopping rod,
21...Through hole, 22...Rotary solenoid, 23...Sewing machine receiving plate, 24...Mounting stand, 25
... Solenoid arm, 26 ... Rotating shaft, 27 ... Long hole, 28 ... Pin, 29, 30 ... Stop bar restriction collar, 31 ... Stop bar return spring, 32 ... Pulse generator, 33 ... Main shaft, 34... Disc, 35... Magnet, 36... Sewing machine body receiving shelf, 37... Element mounting base, 38... Magnetic sensing element, 39... Comparator, 40... Volume, 41... Inverter, 42, 43, 44,
45...Branch line, 46...Flip-flop, 4
7...3 input NAND gate, 48...2 input
NAND gate, 49...inverter, 50...
Integration circuit, 51... 2-input NAND gate, 52...
...Flip-flop, 53...Inverter, 5
4... 2-input NAND gate, 55, 55'... One pulse circuit, 56... Front counter, 57...
2-input NAND gate, 58...Inverter, 5
9...Stitch number determination switch, 60...Transistor, 61...Rear counter, 62...2 inputs
NAND gate, 63... Inverter, 64...
Stitch number determination switch, 65...2 negative input OR gate, 66...Monostable multivibrator, 67
...Transistor, 68...Volume, 69
... Condenser, 70 ... Opening, 71 ... Lint suction pipe, a ... Fabric leading edge slope, b ... Damage.

Claims (1)

[Claims] 1. A known detection device for detecting the arrival of fabric is installed at a position slightly in front of the ring cutting knife, and a fabric edge stop is slidably supported on bearings fixed to the sewing machine body below the fabric sliding plate. A fabric damage prevention device, characterized in that a fabric advancement preventing member is provided with a rod that passes through a through hole in a fabric sliding plate so that it can be moved up and down, and the fabric advancement blocking member is moved up and down in response to a command from the detection device. .