JP2938664B2 - Loom brake circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention
The present invention relates to a loom brake circuit that can stop a loom quickly and reliably.

[0002]

2. Description of the Related Art When stopping a loom, it is necessary to strictly control the stop position and perform so-called fixed position stop. If the stop position of the loom is not constant, not only is the lapping operation at the time of restarting troublesome, but also, particularly in the case of a dobby-equipped machine, there is a possibility that a fatal fabric defect such as a shift in the weaving pattern may occur. Because there is. In addition, it is preferable that such a fixed position stop function is maintained even when the power of the loom is lost due to a power failure.

Therefore, there is known a technique for using a storage element such as a capacitor to effectively operate a loom brake even in the event of a power failure and to reliably stop the loom at a fixed position (Japanese Utility Model Publication No. 61-13572). Gazette). This one is
When the power supply is normal, the power storage element is charged, and when a power failure occurs, the discharge current from the power storage element is supplied to the brake coil to activate the excitation type brake.

[0004]

According to the prior art, when a capacitor is used as a storage element, a circuit system including the capacitor and the brake coil is often a vibration system as a whole. There is a problem that the stationary position cannot be stopped due to a shortage of the power supply time for the motor, and as a result, a shortage of the braking force. That is, if the circuit system is an oscillating system, the energizing current to the brake coil becomes an attenuating oscillating current, and when the first half cycle is energized, it disappears as it is and the pole of the energy charged in the capacitor. This is because only a small portion can be effectively used, and the energization time itself becomes extremely short. The reason why the energizing current is generated only in the first half cycle is that the surge absorbing element or the like connected to the brake coil absorbs the remaining energy in the subsequent half cycle. It is thought that it is.

Accordingly, an object of the present invention is to provide a loom capable of ensuring a quick stop even in the event of a power failure by using an auxiliary element for making the circuit system non-vibrating in view of the problems of the prior art. To provide a brake circuit.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a circuit system comprising a capacitor which is charged when the power supply is normal and an excitation type brake coil which is excited by the capacitor during a power failure. The gist of the invention is to provide an auxiliary element for making the circuit system non-vibrating and a connecting means for inserting the auxiliary element into the circuit system at the time of power failure.

The auxiliary element can be a resistor inserted in series with the brake coil, or a diode inserted in parallel with the brake coil.

Further, the connection means may be operated only when a power failure occurs during operation of the loom.

[0009]

According to the structure of the present invention, the capacitor is charged when the power supply is normal and the brake coil is excited at the time of power failure. At this time, the auxiliary element inserted into the circuit system changes the circuit type to a non-vibration system. Therefore, the current supplied to the brake coil can be a non-oscillating damping current, and therefore, the entire amount of energy charged in the capacitor can be used effectively.

When a resistor is used as an auxiliary element, the condition for making the circuit system non-vibrating is that (R + r) ² ≒ R
^{Since 2} ≧ 4 L / C, the circuit system can be easily made a non-vibrating system by selecting an appropriate resistor R that satisfies this condition. Here, R is a resistance as an auxiliary element, r is a resistance of a brake coil, and L is
The inductance of the brake coil, C, is the capacitance of the capacitor.

When a diode is used as an auxiliary element, the diode functions as a flywheel diode and does not limit the current flowing through the brake coil, so that the total energy charged in the capacitor can be more effectively used. it can.

If the connecting means is activated only when a power failure occurs during the operation of the loom, if the operating state of the loom disappears due to the occurrence of the power failure, even if the power supply is restored, the connection means will not operate. Does not automatically return, so that the connecting means does not needlessly open and close a large current flowing through the brake coil even in the event of an instantaneous power failure or the like.

[0013]

Embodiments will be described below with reference to the drawings.

The brake circuit of the loom comprises a capacitor C,
A relay X and a resistor R are added to a circuit system including the excitation operation type brake coil MB (FIG. 1).

The power supply AC is connected to the input side of the rectifier circuit RF1 via the transformer T1 and also to the input side of the rectifier circuit RF2. Also, the relay X
, And can detect a power failure of the power supply AC.

On the output side of the rectifier circuit RF1, a brake coil MB is connected via a relay contact RNb and a diode D1.
, And a surge absorbing element ZD such as a varistor is connected in parallel to the brake coil MB. The relay contact RNb is a normally closed contact of a relay RN (not shown) indicating that the loom is in operation, and is open when the loom is operating and closed when the loom is stopped.

A capacitor C is connected to an output side of the rectifier circuit RF2. The positive electrode on the output side of the rectifier circuit RF2 is connected to a connection point between the diode D1 and the brake coil MB via a transistor TR, a diode D2, and a parallel circuit of a resistor R and a normally open contact Xa of a relay X. I have. Incidentally, the negative electrodes of the rectifier circuits RF1 and RF2 are commonly connected.

A gate signal Sg from a gate circuit 11 is input to the base of the transistor TR. The gate circuit 11 has a normally closed contact Xb of a relay X and a loom stop signal Ss from a loom control circuit (not shown). Is entered.

When the power supply AC is normal and the loom is in operation, the relay contact RNb is open and the relay X is operating. Further, the transistor TR is cut off. Therefore, in this state, the current i flowing through the brake coil MB is i = 0, and the brake is not operating at all. The capacitor C is charged by the output of the rectifier circuit RF2.

When the loom is stopped automatically or manually, the relay contact RNb is closed and a loom stop signal Ss is generated in the loom control circuit. Therefore, if the gate circuit 11 generates the gate signal Sg having the pulse width T in response to the loom stop signal Ss (FIG. 2), the loom stop signal Ss is generated for the brake coil MB. Immediately after this, the energizing current i = i2 can be applied, and after the lapse of time T, the energizing current i = i1 can be applied. Here, the current i1 is equal to the relay contact RN
b, a current supplied from the rectifier circuit RF1 via the diode D1, and a current i2 is a current supplied from the rectifier circuit RF2 via the transistor TR, the diode D2, and the relay contact Xa. The current i1 is substantially equal to or slightly smaller than the rated current of the brake coil MB. The voltage of the power supply AC and the winding ratio of the transformer T1 are:
Assuming that i22i1 is established, the brake coil MB is so-called over-excited with respect to the brake by applying a current i = i2 which is larger than the rated current over time T at the beginning of its operation. Large braking force can be generated.

Next, consider a case where a power failure occurs during operation of the loom and the power supply AC is lost.

At this time, since the relay X first returns, the gate circuit 11 can send the gate signal Sg to the transistor TR in correspondence with the normally closed contact Xb of the relay X. The resistor R is a normally open contact Xa of the relay X.
Is opened, and is inserted in series with the brake coil MB. The current i1 from the rectifier circuit RF1 is equal to the power supply A
Due to the loss of C, i1 = 0. That is,
The circuit system at this time is equivalent to a series resonance circuit in which a capacitor C excites a brake coil MB including a resistor r and an inductance L via a transistor TR and a resistor R (FIG. 3). Therefore, (R + r) ² ≒ R ² ≧ 4L
If the resistor R is selected so that / C is established, this circuit system becomes a non-vibrating system, and the current i = i2 supplied to the brake coil MB becomes a simple non-vibrating damping current, and charges the capacitor C. It is possible to effectively use all the energy that has been used.

[0023]

Other Embodiments The capacitor C can be charged with a high voltage by using a transformer T2 and a rectifier circuit RF3 (FIG. 4).

Here, a smoothing capacitor C1 is connected to the output side of the rectifier circuit RF2, and a brake coil MB is connected via a transistor TR and a diode D2.
Is connected. Further, the resistor R is connected to the brake coil MB via a normally closed contact Xb of the relay X. Note that only the loom stop signal Ss is input to the gate circuit 11, and the transformer T1 and the rectifier circuit RF shown in FIG.
The diode D1 for supplying the current i1 from
It is connected to the brake coil MB.

When the loom is stopped when the power supply AC is normal, the transistor TR is turned on for a predetermined time by the loom stop signal Ss, so that a current i = i2 can be supplied to the brake coil MB. At this time, since the normally closed contact Xb of the relay X is open, the rectifier circuit RF2,
The current i3 from the capacitor C is i3 = 0.

If the power supply AC is lost during operation of the loom, the relay X returns and the normally closed contact Xb closes. Therefore,
The energizing current i to the brake coil MB is i = i3, and the energizing current i at this time is non-oscillating damping because the resistor R is inserted in series and the circuit system is non-oscillating. It is a current. Since the capacitor C can be charged to a sufficiently high voltage by the transformer T2, the resistance R
Are inserted in series, the current i = i3 can be sufficiently increased. The transformer T2 and the rectifier circuit RF3
May be replaced with an n-fold voltage rectifier circuit. Where n is
It is an arbitrary integer of 2 or more.

With respect to the capacitor C, the transistors TR,
The brake coil MB may be connected via the diode D2 (FIG. 5), and a series circuit of the normally closed contact Xb of the relay X and the diode FD may be connected in parallel to the brake coil MB. It is assumed that the normally closed contact Xb of the relay X and the loom stop signal Ss are input to the gate circuit 11 at this time, as in FIG.

At the time of the power failure of the power supply AC, the relay X returns, so that the diode FD is inserted in parallel with the brake coil MB, and the diode FD at this time acts as a flywheel diode. That is, even if the circuit system including the capacitor C and the brake coil MB is an oscillating system, the diode FD is connected to the brake coil M
The energizing current i of B can be a non-oscillating damping current. It should be noted that the diode FD may be a series circuit of an appropriate low-current limiting resistor and a diode instead of a single diode.

The relay X can be connected to a power source AC via a relay contact RNa that is closed during operation of the loom, and can be self-held (FIG. 6). Even if an instantaneous power failure occurs in the power supply AC, the relay contacts RN
Since a is opened and the relay X is restored, even if the power supply AC is restored within a very short time thereafter, the relay X is not turned on again. Therefore, the normally closed contact Xb of the relay X does not interrupt the large energizing current i flowing through the brake coil MB, and the relay X only needs to have an extremely small contact capacity.

In the above description, when the circuit system including the capacitor C and the brake coil MB is a vibration system, the resistor R and the diode FD are auxiliary elements for making the circuit system a non-vibration system. The normally open contact Xa and normally closed contact Xb of the relay X connect the resistor R in series with the brake coil MB or insert the diode FD in parallel with the brake coil MB when a power failure occurs in the power supply AC. Connection means for connection. It should be noted that the relay X can be replaced with any other power failure detecting means, and the normally open contact Xa and normally closed contact Xb can be replaced with any other switching element. . Further, the transistor TR in each of the above embodiments can be replaced with another arbitrary switching element.

In each of the above embodiments, the gate circuit 11 also inputs a fixed position signal indicating that the rotation angle of the main shaft of the loom is at a fixed position, and outputs the fixed position signal, the loom stop signal Ss, and the relay. The gate signal Sg may be output after an AND condition with one or both of the normally closed contacts Xb of X is taken. A so-called fixed-position stop function can be realized when one or both of the loom stop signal Ss and the power failure occur.

[0032]

As described above, according to the present invention, with respect to a circuit system including a capacitor and a brake coil, an auxiliary element which makes this circuit system a non-vibration system and an auxiliary element are inserted into the circuit system. By providing connection means,
Since the auxiliary element can make the energizing current of the brake coil a non-oscillating damping current, the brake coil can effectively use the entire energy charged in the capacitor, and therefore, even during a power failure, There is an excellent effect that the loom can be stopped quickly without fail.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the overall configuration.

FIG. 2 is an operation explanatory diagram.

FIG. 3 is an equivalent circuit diagram

FIG. 4 is a view (1) corresponding to FIG. 1 showing another embodiment.

FIG. 5 is a diagram (2) corresponding to FIG. 1 showing another embodiment.

FIG. 6 is a main part circuit diagram showing another embodiment.

[Explanation of symbols]

 AC: Power supply MB: Brake coil C: Capacitor R: Resistance FD: Diode

Claims (4)

(57) [Claims] A capacitor that is charged when the power supply is normal;
For a circuit system consisting of an excitation operation type brake coil that is excited by the capacitor at the time of a power failure, an auxiliary element that makes the circuit system a non-vibration system, and a connection unit that inserts the auxiliary element into the circuit system at the time of a power failure. The loom brake circuit provided. 2. The brake circuit according to claim 1, wherein the auxiliary element is a resistor inserted in series with the brake coil. 3. The loom brake circuit according to claim 1, wherein the auxiliary element is a diode inserted in parallel with the brake coil. 4. The connection means according to claim 1, wherein the connection means operates only when a power failure occurs during operation of the loom.
4. A brake circuit for a loom according to claim 3.