JPH0729978Y2 - Automatic thread cutting device for sewing machines with cloth conveying device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an automatic thread trimming technology for an empty ring formed by sewing, and is an automatic sewing machine with a cloth conveying device that automatically feeds cloth after sewing is completed. The present invention relates to a thread cutting device.

[Conventional technology]

2. Description of the Related Art Conventionally, as an automatic thread trimming device for a sewing machine with a cloth conveying device that automatically feeds cloth after the end of sewing, those having a structure as shown in FIGS. 8 and 9 have been used. That is, the construction is such that the cloth detection sensor 5 is provided on the cloth insertion side (front) of the sewing machine head 3 provided with the presser foot 4 located above the table 2, and the thread arranged below the table 2 is provided behind the presser foot 4. The suction port 6 of the cutting device 1 is opened, and the empty ring b following the end of the sewn portion of the cloth a is sucked into the suction port 6 for cutting. The thread cutting device 1 includes an intake pipe 7 near the suction port 6.
The cutter 8 provided on the inner surface of the upper wall is sliding like a scissors.
The sewn cloth a is placed behind the suction port 6 in the stack portion 10
A cloth feeding cylinder 12 is installed as a cloth conveying device 11 for feeding the cloth to the. Then, the cloth feed cylinder 12 is configured such that the slow feed solenoid valve 13a and the fast feed solenoid valve 13b are connected to the shortening side port, and the return solenoid valve 13c is connected to the extending side port,
Further, a cloth pressing cylinder 15 is fixed to the end of the rod 14 of the cloth feeding cylinder 12. The presser foot cylinder 15 is the table 2
A presser foot 17 is fixed to the end of a rod 16 that vertically moves toward and away from the rod, and a presser foot solenoid valve 18 is connected to the air supply port. A stack portion 10 composed of a bar stacker 19 for stacking the fed cloths a and a stacking base 20 is provided at the end of the table 2 in the shortening operation direction of the cloth feeding cylinder 12.

The presser foot 17 of the conventional cloth conveying device 11 having such a structure
As shown in FIG. 8, the step of moving the cloth feed cylinder 12 to the cloth feed position accompanying the extension drive, the step of pressing the sent cloth a by the extension drive of the cloth pressing cylinder 15, and the pressing of the cloth a is a slow cloth feed process in which the cloth feed cylinder 12 is driven at a low speed to drive the cloth a halfway, a fast cloth feed process is performed in which the cloth feed cylinder 12 is driven at a fast speed to drive the cloth, and a cloth presser cylinder 17 is pressed. The cloth a, which has been sewn under the sewing machine head 3, is transferred to the stack section 10 by taking the orbit of the five steps of raising and releasing the cloth a.

The thread cutting device 1 cuts the continuous empty ring b from the sewn end of the cloth a during the conveyance of the cloth a by the cloth conveying device 11, and therefore the moving speed in the slow cloth feeding step ( As shown in FIG. 9, the arrow V1) is adjusted so as to be slower than the speed at which the empty ring b is formed and extends under the sewing machine head 3 (arrow V2), and the slack portion of the empty ring caused by this speed difference. b'is sucked from the suction port 6 toward the air supply pipe 7, and the slack part b'of the hollow ring is cut by a cutter 8 provided in the vicinity of the suction port 6.

[Problems to be solved by the device]

However, in the above-described conventional cloth conveying device 11, in the cloth feeding process, the feeding speed V1 of the cloth feeding cylinder 12 is made very slow with respect to the sewing speed V2 by the sewing machine head 2 so that the thread trimming device 1 has an empty ring b and a slack portion b. 9'is sucked, but as shown in FIG. 9, the slack part b'of the empty ring sucked from the suction port 6 to the air supply pipe 7 wraps around the back side of the swing blade of the cutter 8 to lower the pipe wall. Since it is in a state of slowly extending along the arrow (arrow A), the fixed blade and the swing blade may not be cut, which causes a problem of uncertain thread cutting work.

In order to solve such a drawback, conventionally, a method of cutting an empty ring b continuous with the cloth a from above with a knife has been proposed, but this method causes another problem such as cutting the cloth a. It was.

The present invention has been made in view of the above problems, and an object thereof is to stably and reliably cut an empty ring sucked from a suction port of a thread cutting device. An object of the present invention is to provide an automatic thread cutting device for a sewing machine with a cloth transporting device that controls and drives the feeding of cloth so that the empty ring sucked from the suction port is stably and surely cut.

[Means to be solved by the invention]

That is, the automatic thread cutting device of the sewing machine with the cloth conveying device of the present invention is
The cloth feed cylinder and the cloth presser cylinder provided at the rod end of the cloth feed cylinder feed the sewn cloth with a movement locus on the suction port of the thread trimming device opened on the table, In the sewing machine with the cloth conveying device, the empty ring formed at the end of the cloth is sucked from the suction port in the direction of the cutter of the thread cutting device and cut, and then the cloth is transferred to the next step by the cloth feeding cylinder. A feed solenoid valve and a return solenoid valve are respectively provided between the air supply port and the air supply source that have different drive directions of the cloth feed cylinder, and both the solenoid valves are configured to be driven and controlled by a central control device. When the cloth is transferred, after the rear end of the cloth exceeds the suction port, the cloth is moved back by a predetermined stroke toward the suction port, a slack portion is formed in the empty ring, and the slack portion is automatically transferred to the suction port of the thread cutting device. It is an Abstract that sheet.

[Action]

According to the above configuration, the cloth sewn by the cloth conveying device is transferred to the next step so that the empty ring passes over the suction port of the thread cutting device,
After the rear end of the cloth moves past the suction port during the transfer, the cloth is moved back toward the suction port with a predetermined stroke (return feed operation), and this is combined with the growth of the empty ring formed under the sewing machine head. A large number of empty rings continuous to the end of the cloth are fed to the suction port of the thread cutting device at a time. Therefore, the yarn of the empty ring can be reliably cut by the cutter.

〔Example〕

An embodiment of an automatic thread cutting device for a sewing machine with a cloth conveying device according to the present invention will be described below with reference to FIGS. 1 to 7.

Referring to the schematic view of FIG. 1, the automatic thread trimming device for a sewing machine with a cloth transporting device according to the present invention detects a cloth on the cloth insertion side (front) of a sewing machine head 3 provided with a presser foot 4 located above a table 2. A sensor 5 is provided, and a suction port 6 of a thread cutting device 1 installed below the table 2 is opened behind the presser foot 4, and an empty ring b continuing to the end of the sewn portion of the cloth a is provided at the suction port 6. It inhales and cuts. As shown in FIGS. 3 and 4, the thread cutting device 1 has a cutter 8 formed on the inner surface of the upper wall of the intake pipe 7 adjacent to the suction port 6, and is a fixed blade fixed to the upper wall. The rocking blade 8b is slid like a scissor with the shaft 9 as a rocking shaft with respect to 8a, and at the same time, an intake device (not shown) such as a blower connected to the rear end of the intake pipe 7 sucks air at an appropriate speed (arrow B). )is doing. In addition, a sewn cloth a is provided behind the suction port 6.
As the cloth conveying device 11 for feeding the sheet to the stacking section 10, the cloth feeding cylinder 12 for controlling the drive of the present invention is installed. The cloth feed cylinder 12 has a feed solenoid valve 13A connected to the shortening side port 12a and a return solenoid valve 13B connected to the extension side port 12b. The presser cylinder 15 is fixed. The cloth presser cylinder 15 has a cloth presser 17 fixed to the end of a rod 16 that vertically extends and retracts toward the table 2, and also has an air supply port 15
A cloth presser solenoid valve 18 is connected to a, and the cloth a is clamped or released between the table 2 surface. Then, at the end of the table 2 in the shortening direction of the cloth feed cylinder 12,
A bar stacker 19 and a stacker 20 for stacking the sent cloth a
It has a structure in which a stack portion 10 consisting of (the next step) is provided.

And these configurations are the cloth feed cylinder 12 and both ports.
The structure is almost the same as the conventional structure described above except the feed solenoid valve 13A and the return solenoid valve 13B connected to 12a, 12b.

FIG. 2 shows a control device having the structure shown in FIG. 1, which controls and drives the cloth feed cylinder 12 and the cloth presser cylinder 15 via the feed solenoid valve 13A, the return solenoid valve 13B and the cloth presser solenoid valve 18. The central control unit (CPU) 21 is connected to the ROM 22 and the RAM 23, and the CPU 21 is connected to the cloth detection sensor 5 and the drive circuit 25 via the input / output port 24. The drive circuit 25 is connected to the feed solenoid valve 13A, the return solenoid valve 13B, and the presser foot presser foot solenoid valve 18.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. 6 with reference to the explanatory diagram of the drive locus of the cloth conveying device 11 and the cloth presser 17 shown in FIG.

(1) First, when the apparatus is started, a cloth detection sensor 5 provided in the vicinity of the sewing machine head 3 determines whether or not the cloth a has been fed. When the cloth a is fed, the sewing machine motor of the sewing machine head 3 ( (Not shown) operates to drive sewing. Here, the feed electromagnetic 13A communicating with the cloth feed cylinder 12
Is turned on, the cloth feed cylinder 12 is operated, and the rod 14 is driven to extend to a predetermined position (step of moving to the cloth feed position).

(2) Next, it is determined whether or not the cloth a has passed through the cloth detection sensor 4. Time from when cloth a passed through here
When T1 is measured, it is judged whether or not the set timer time has elapsed, and if so, the work clamp of the work clamp cylinder 15 is turned on and the work clamp solenoid valve 18 is turned on to the extension side (normal) and the work clamp is pressed. 17 is lowered to hold the cloth a. (Step of pressing the sent cloth a) (3) Next, when the return solenoid valve 13B is turned on, the cloth feed cylinder 12 is driven to shorten and the cloth presser 17 presses the cloth a with the upper surface of the table 2. Feeding movement in a state of being held (passing feeding process on the suction port 6 before cutting the empty ring b: see FIG. 7 (a))
To do. Then, the time from when the cloth feed cylinder 12 starts to shorten is measured, and it is determined whether or not the set timer time T2 has elapsed. If the time has passed, the cloth feed cylinder 15
Turn off the feed solenoid valve 13A and turn the return solenoid valve 13b
Set to N.

(4) As a result, the cloth feed cylinder 12 expands at a speed such that the empty ring b connected to the cloth a is drawn into the suction port 6 in the expanded state, and performs the "returning feed operation". In conjunction with the supply of the empty ring b, as shown in FIG. 7 (b), a slack a'of the empty ring is generated behind the cloth a and the slack b'is generated by the suction B of the thread cutting device 1. It is drawn in through the suction port 6. The slack b ′ of the hollow ring dramatically increases the probability of entering between the fixed blade 8a and the swinging blade 8b of the cutter 8 which is being driven by scissors, and ensures cutting by both blades. By measuring the time from the start of the expansion of the feed cylinder 12, it is determined whether or not the set timer time T3 has elapsed, and if so, the return solenoid valve 13B of the cloth feed cylinder 15 is turned off. At the same time, the feed solenoid valve 13A is turned on. (Returning feed step of forming slack b'on the empty ring b) (5) When the feed solenoid valve 13A is turned ON, the cloth feed cylinder 12 is shortened again to feed the cloth a to the stack portion 10 position (next Sending process to move to the process). At the same time, it is judged whether or not the time of the thread trimming timer has elapsed, and
When T4 has passed, the sewing machine motor is turned off. Next, it is judged whether or not the cloth feed cylinder 12 has been shortened, and the return solenoid valve 13B is turned off.

(6) And the work clamp of the work clamp cylinder 15 The work clamp solenoid valve 18
Turns ON to the suction side (negative), and the presser foot 17 rises to release the cloth a (the step of releasing the sent cloth a). At that time,
Part of the sent cloth a hangs from the table 2, so
The bar stacker 19 rotates, the cloth a is stacked on the stacking base 20, and a series of operations is completed.

However, when the next cloth a is fed, the cloth detection sensor 5 operates and the above steps are repeated again.

In the above-described embodiment, the one in which the "return feeding operation" is performed at the time of the feeding operation of the cloth feeding cylinder 12 has been described, but it goes without saying that the returning feeding operation can be repeated twice or more.

[Effect of device]

As described above, the automatic thread cutting device of the sewing machine with the cloth conveying device according to the present invention is driven by the cloth conveying device for transferring and discharging the sewn cloth so that the empty ring passes over the suction port of the thread cutting device. In order to increase the probability that the empty ring formed at the end of the cloth will be sent to the suction port of the thread cutting device and the empty ring will interfere with the cutter, due to the configuration in which the "return feeding operation" is performed during the transfer, It has a feature that the thread of the empty ring following the cloth can be surely cut, and the practical effect after the present invention is implemented is extremely large.

[Brief description of drawings]

1 is a schematic configuration diagram showing an embodiment of an automatic thread cutting device for a sewing machine with a cloth conveying device according to the present invention, FIG. 2 is a block diagram of a control device for controlling each part of the device of FIG. 1, and FIG. FIG. 4 is a plan view of a main part of the thread cutting device, FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3, FIG. 5 is an operation explanatory view of the device of FIG. 7A and 7B are explanatory views showing a thread cutting operation, FIG. 8 is a schematic configuration diagram of a conventional thread cutting sewing machine with a cloth conveying device, and FIG. FIG. 9 is an explanatory view of the operation of the thread cutting device according to FIG. 8. 1 ... Thread trimming device, 2 ... Table 3 ... Sewing machine head, 5 ... Cloth detection sensor 6 ... Suction port, 8 ... Cutter 8a ... Fixed blade, 8b ... Oscillating blade 10 ... Stack part, 11 ... Cloth transport device 12 ... Cloth Feed cylinder, 13A ... Feed solenoid valve 13B ... Return solenoid valve, 15 ... Work clamp cylinder 18 ... Solenoid valve, 19 ... Bar stacker 20 ... Stack, 21 ... Central control unit

Claims (1)

[Scope of utility model registration request] 1. A locus of movement of a sewn cloth on a suction port of a thread cutting device which opens a sewn cloth on a table by a cloth pressing and cloth feeding action of a cloth feeding cylinder and a cloth pressing cylinder provided at a rod end of the cloth feeding cylinder. And a cloth conveying device for sucking the empty ring formed at the end of the cloth from the suction port in the direction of the cutter of the thread cutting device to cut the cloth, and then transferring the cloth to the next step by the cloth feeding cylinder. In a sewing machine with a structure, a feed solenoid valve and a return solenoid valve are respectively provided between an air supply port and an air supply source having different driving directions of the cloth feed cylinder, and the both solenoid valves are drive-controlled by a central controller, When the cloth feeding cylinder is transferred, the cloth rear end moves past the suction port and then returns to the suction port by a predetermined stroke to form a slack portion in the empty ring, and the slack portion is sucked by the thread cutting device. Automatically automatic thread switching device of the fabric conveying device with a sewing machine, characterized in that the supply to the.