JPS5913237B2 - Sewing machine thread trimming control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thread trimming control circuit for reliably performing the thread trimming operation of an industrial high speed sewing machine having, for example, a fixed position stop device.

Conventionally, the thread trimming control circuit in this type of sewing machine is driven by multiple relays, but normally there is a delay in the operation of the relays due to their function, so reliable and quick operation cannot be achieved. Not only is this relay installed in a sewing machine that generates a lot of vibration, it is prone to malfunction, and the contacts also wear out quickly, resulting in a shortened life span and reliability.

- This invention has been made with attention to this point, and it is an object of the present invention to provide a thread trimming control circuit that can quickly and reliably perform thread cutting operations without using relays.

That is, FIG. 1 shows one embodiment of this invention.
1 is, for example, a drive shaft of a sewing machine equipped with a fixed position stop device;
'For example, a first switch device that is turned ON during operation of the upper shaft (not shown); 2 is a memory circuit that stores the operation of the first switch device 1; 3 is this memory circuit 2;
A first semiconductor switching element, such as a transistor, operated by the output of 4, a second switching device 5 which is turned ON in the needle lowering position of the sewing machine;
The collector output of the first semiconductor switching element 3 is at a high potential, and the second switching device 4 is "ON".
a second semiconductor switching element that becomes conductive when 6
7 is the third switch device that is operated 1ONJ during the thread cutting operation of the sewing machine, and 7 is rOFF of this third switch device 6.
A fourth manual switch device that prohibits the thread cutting operation of the sewing machine during the J operation; 8 is both the above-mentioned switch devices; 6 and 7 are both r
ON J - a third semiconductor switching element which is in operation and becomes non-conductive when the output of the second semiconductor switching element 5 is at a low potential; 9 is a thread trimming solenoid of the sewing machine; 10 is the third semiconductor switching element; a fourth semiconductor switching element operated by the semiconductor switching element 8 to drive the thread cutting solenoid 9; 11 is a DC power supply;
1-R14 is a fixed resistor.

Since the thread trimming control circuit of the present invention is configured as described above, when the sewing machine starts operating, the first switching device 1 is turned "ON" and the output of the memory circuit 2 is at a low potential. ing.

Therefore, the base 2 of the first semiconductor switching element 3
Since no current is supplied to it, it is in a non-conducting state.

Next, when the second switching device 4 is turned ON in the needle lowered position, the resistor R4J is connected to the DC power supply 11.
A current is supplied to the base of the second semiconductor switching element 5 through R, and the second semiconductor switching element 5 becomes conductive, so that the collector of the second semiconductor switching element 5 has a low potential.

On the other hand, as a thread trimming signal, the third switch device 6
When the third semiconductor switching element 8 is operated, the base of the third semiconductor switching element 8 becomes completely low potential, and as a result, the third semiconductor switching element 8 becomes non-conductive, and as a result, the base of the fourth semiconductor switching element 10 DC power supply 1
Since current is supplied from R1 through resistor R13, it becomes conductive and the thread trimming solenoid 9 is driven.

That is, the circuit including the fourth semiconductor switching element 10 constitutes a thread cutting solenoid drive circuit, and the circuit including the third semiconductor switching element 8 controls the operation of the fourth semiconductor switching element 10 by its output. This constitutes a thread trimming solenoid drive control circuit.

To simplify the operation described above, when the second, third and fourth switch devices 4, 6.7 are all "ON", the thread trimming solenoid 9 is driven, and the third
When the switch device 6 is turned off, the thread cutting operation is completed.

Next, when the sewing machine reaches the needle up position, the memory in the memory circuit 2 is canceled and its output is reversed from low potential to high potential. Therefore, after the sewing machine stops at the needle up position, the second and third switch devices 4 and 6 are configured such that the thread trimming solenoid 9 is not driven even if the ONJ operation is performed.

On the other hand, if the second switch device 4 is turned on while the fourth manual switch device 7 is initially rOFFJ, the collector of the second semiconductor switching element 5 becomes low potential; The base of the third semiconductor switching element 8 is always supplied with current from the DC power supply 11 via the resistors R0 and R11 without being affected by the operation of the third switching device 6. The switching element 8 is always in a conductive state, that is, when the fourth manual switch device 7 is operated "0FFJ,"
The output of the thread trimming solenoid drive control circuit is disabled, and the thread trimming solenoid 9 is not driven.

However, when the sewing machine reaches the needle-up position, the memory in the memory circuit 2 is canceled and the sewing machine stops at the needle-up position, as described above.

That is, when the fourth manual switch device 7 is set to rOFFJ, the thread trimming solenoid 9 is not driven, but the sewing machine stops at the needle up position, and the switch device 1 of the cylinder 1 is turned off again.
Needless to say, no operation is performed unless the switch is turned "ON".

It is assumed that a reed switch, a microswitch, a relay, or the like is used as each of the above-mentioned switch devices 1, 4, 6.7.

As described above, according to the present invention, the thread trimming solenoid is driven by a semiconductor switching element such as a transistor, without using a relay that has a delay in its operation and is likely to malfunction due to vibration. Because of this, the thread cutting operation can be performed quickly and reliably, resulting in an excellent effect.

Further, according to the present invention, since a semiconductor switching element such as a transistor is used to control the thread trimming solenoid 9, there is no wear of contacts unlike a relay, and an inexpensive and highly reliable control circuit is provided. It also has the effect of being able to

Furthermore, since a manual switch device is provided that disables the output of the thread trimming solenoid drive control circuit and prohibits thread trimming, when this manual switch device is operated, the output of the thread trimming solenoid control circuit is disabled. The sewing machine can be stopped at the needle up position without the thread trimming solenoid being driven.

[Brief explanation of drawings]

The figure is a thread trimming control circuit diagram of a sewing machine showing an embodiment of the present invention. In the drawings, 1 is a first switching device, 2 is a storage circuit,
3 is a first semiconductor switching device, 4 is a second switch device, 5 is a second semiconductor switching device, and 6 is a third semiconductor switching device.
, 7 is a fourth manual switch device, 8 is a third semiconductor switching element, 9 is a thread trimming solenoid, 10 is a fourth semiconductor switching element, 11 is a DC power supply, and R1 to R14 are fixed resistors. It is.

Claims (1)

[Scope of Claims] 1. A detector that detects the needle position of the sewing machine and outputs a needle up position signal and a needle down position signal, and a detector that stores the operation of a switch device operated during operation of the sewing machine, and a memory circuit whose memory is canceled by the needle lowering position signal, and a semiconductor switching element which responds to the output of this memory circuit and the needle lowering position signal and generates an output when the thread trimming switch device is operated. and a thread trimming solenoid drive surface comprising a semiconductor switching element that drives the solenoid under the control of the output of the thread trimming solenoid drive control circuit. A system cutting control circuit for a sewing machine characterized by: 2. A thread cutting control circuit for a sewing machine according to claim 1, characterized in that the semiconductor switching element is a transistor. 3. A thread cutting control circuit for a sewing machine according to claim 1, characterized in that the semiconductor switching element is a transistor. A detector that outputs a raised position signal and a needle lowered position signal, a memory circuit that stores the operation of a switch device operated during operation of the sewing machine, and whose memory is canceled by the needle raised position signal, and this memory circuit. a thread trimming solenoid drive control circuit consisting of a semiconductor switching element that responds to the output of the above and the needle lowering position signal and generates an output when the thread trimming switch device is operated; A thread trimming solenoid drive circuit comprising a semiconductor switching element that is controlled by the output of the circuit to drive the solenoid, and a thread trimming operation prohibition switch device that is manually operated to disable the output of the thread trimming solenoid drive control circuit. 4. A thread trimming control circuit for a sewing machine, characterized in that the semiconductor switching element is a transistor.