JPH02160952A - Reeling sensor for stationary drum weft measuring and storing apparatus - Google Patents

Abstract

PURPOSE:To attain sufficiently high S/N ratio even in the case of a colored yarn by supplying electric power to a light-projection element in a stationary drum using an excitation coil and an induction coil placed opposite to each other interposing a gap therebetween and forming a transmission-type photo- sensor. CONSTITUTION:A transmission-type photo-sensor for a reeled yarn W is formed of a light-projection element 11a and a light-receiving element 11b separately placed at the inside and outside of a stationary drum D. Electric power is supplied to the light-projection element 11a, etc., by an induction coil 12b placed at the side of the stationary drum and an excitation coil 12a placed outside of the stationary drum.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention is used in a loom to detect the amount of yarn that is wound or stored on a fixed drum, or to unwind the yarn for weft insertion. The present invention relates to an unwinding sensor for a fixed drum type weft length measurement and storage device for accurately counting the number of unwound turns when unwinding.

There are two types of drum-type weft length measurement and storage devices for conventional looms: a fixed drum type and a rotating drum type. It depends on whether the yarn guide rotates.

The former is because a locking member for locking and unwinding the wound yarn can be disposed outside the drum.
Its entire structure is in a cylinder, and it is widely used for boat fishing.

The latter has a rotating drum that slows down the unwinding speed of the yarn, which makes it possible to make the balloon smaller and reduce the unwinding resistance.In addition, there are fewer bending points in the yarn travel path, allowing the yarn to be fed easily. Therefore, it is suitable for heavy thick yarns and special yarns with poor flexibility.

In a fixed drum type weft length measuring device, for each pick,
In order to accurately unwind a predetermined length of yarn from a fixed drum, the locking member, which is driven to the unwinding position at a predetermined time and starts unwinding the yarn, must be moved at the point when a predetermined number of turns of yarn have been unwound. , just return it to its locked position.

For example, if n turns of yarn are to be unwound for each pick, the locking member should be returned immediately after (n-1) turns of yarn are unwound, and the number of unwound turns can be detected. An unwinding sensor is used.

Conventional unwinding sensors are usually so-called reflective optical sensors installed outside of a fixed drum. The thread moving in the axial direction on the circumference of the drum and being unwound from the tip of the drum is detected by a separately provided light receiving element.

In addition, while the loom is in operation, the rotation amount of the motor for winding is controlled so that the amount of yarn stored on the fixed drum is always constant. A reflective optical sensor based on the same principle is also used as a sensor.

The problem to be solved by the invention is that, depending on the type of yarn, it may be difficult to stably count the number of unwound turns or accurately detect the amount of yarn stored, depending on the type of yarn. The problem was that there were quite a few. That is, in the unwinding sensor as described above, the reflected light signal obtained from the light receiving element includes a large bias component due to the reflected light from the circumferential surface of the drum in addition to the signal component due to the reflected light from the yarn. Moreover, since this bias component fluctuates irregularly due to vibrations of the drum, etc., it is difficult to distinguish it from the signal component. In addition, in the case of colored threads other than white threads, the level of reflected light from the thread is small, and therefore the signal component is also small, making it extremely difficult to secure a predetermined signal-to-noise ratio. It is.

On the other hand, if either the light emitting element or the light receiving element is arranged on the fixed drum side to form a transmission type optical sensor, a significant improvement in the signal-to-noise ratio can be expected. Because the drum is completely surrounded at its rear and front by the rotating yarn guide and the unwinding yarn,
There was a problem in that it was difficult to supply power to the light projecting elements and the like on the fixed drum side.

Therefore, in view of the actual state of the prior art, it is an object of the present invention to supply power to a light projecting element etc. disposed within a fixed drum by using an excitation coil and an induction coil that face each other with an air gap between them. By forming a transmission type optical sensor,
It is an object of the present invention to provide an unwinding sensor for a fixed drum type weft length measuring and storage device that can ensure a sufficiently large signal-to-noise ratio even in the case of colored yarns, etc., and can always operate stably.

Means for Solving the Problems The structure of the present invention for achieving the object includes a light emitting element, a light receiving element, an induction coil, and an excitation coil, and the light emitting element is disposed inside a fixed drum. The light receiving element is arranged outside the fixed drum to receive the optical axis from the light emitting element, and the induction coil is arranged so that the thread unwound from the fixed drum crosses the optical axis. The excitation coil is mounted on the circumferential surface of the fixed drum, and the excitation coil is placed outside the fixed drum and faces the induction coil through a gap that serves as a thread passage, and the light emitting element is powered by the output of the induction coil. The gist is what we have done.

Note that a stabilizing circuit may be interposed between the induction coil and the light projecting element.

In addition, the light emitting element and the light receiving element are arranged on the outside and inside of the fixed drum, respectively, and the thread signal from the light receiving element is transmitted to a signal processing circuit powered by the output of the induction coil, and a non-contact signal transmission. It may be pulled out to the outside of the fixed drum via means.

Furthermore, a light projecting element disposed on the fixed drum side or
A light-transmitting member that is wiped away by a thread can be attached to the front surface of the light-receiving element.

Accordingly, with this configuration, if the excitation coil is excited with alternating current, a voltage can be generated in the induction coil by electromagnetic induction, so that the light projecting element can be operated by this voltage. The yarn unwound from the fixed drum is
Since the light-emitting element crosses the optical axis of the light-emitting element and the light-receiving element receives this optical axis, the light-emitting element and the light-receiving element form a transmission type optical sensor, and regardless of the type of thread, the necessary and sufficient signal-to-noise is achieved. You can get the ratio. Further, since there is a gap between the excitation coil and the induction coil, which serves as a thread passage, there is no problem in the length measurement and storage operation of the thread.

When a stabilizing circuit is interposed between the induction coil and the light emitting element, even if there is a fluctuation in the output voltage of the induction coil due to vibration of the fixed drum, this can be stabilized.
The amount of light from the light projecting element can be made constant, and stable operation can be realized.

Similarly, when the light emitting element is placed outside the fixed drum and the light receiving element is placed inside, a transmission type optical sensor can be formed, and the thread signal at this time is the output of the induction coil. It can be taken out to the outside of the fixed drum via a signal processing circuit powered by and a contactless signal transmission means.

If a translucent member is attached to the front surface of the light emitting element or light receiving element disposed on the fixed drum side, this translucent member can be constantly wiped away by the thread released from the fixed drum. There is no risk of a decrease in the amount of light due to the accumulation of fluff on the element.

It works as described above.

Example Examples will be described below with reference to the drawings.

The unwinding sensor of the fixed drum type weft length measuring and storage device (hereinafter simply referred to as the storage device) includes a light emitting element 11a, a light receiving element 11b, an excitation coil 12a, and an induction coil 12b as main components (the Figure 1).

The storage device includes a hollow yarn guide YG protruding from a rotary shaft SH, and a fixed drum D attached to the tip of the rotary shaft SH.

It is assumed that the rotating shaft SH is rotationally driven by a drive source (not shown), and yarn W from a yarn supplying body (not shown) is supplied through a hole SHI formed along the axis thereof. The yarn guide YG communicates with the hole SHI and is connected to the rotation axis S.
It is a pipe-shaped member that projects obliquely toward the tip of the H.

Fixed drum D is mounted with bearing BGSBG..., bracket BK, and flanges FR and PR.

The fixing pin FRI is attached to the tip of the rotating shaft SH via the fixing pin FRI so as to be rotatable relative to the rotating shaft SH. Further, the bracket BK faces the fixed frame F through a gap G that serves as a passage when the yarn guide YG rotates, and its rotation is restrained by the attractive force of the permanent magnets MG, MG, etc. There is.

The fixed drum D has a rear oblique part DI and a front parallel part D2.
It has a circumferential surface D3 that is smoothly continuous and is formed into a cap shape as a whole. Further, the tip of the yarn guide YG extends to the outer periphery of the rear end of the fixed drum D. A locking pin K is disposed near the front end of the fixed drum D, facing a recessed hole D4 formed on the circumferential surface D3.

However, the locking pin has a locking position in which it is driven by a control device (not shown) and its tip enters the recessed hole D4;
It is assumed that it can take an unraveling position in which it completely exits from the recessed hole D4.

The light projecting element 11a is disposed inside the fixed drum t-, D, and is connected to the fixed drum D through a small hole D5 bored in the peripheral surface D3.
It faces the light receiving element 11b arranged outside. However, in order to count the number of released turns of the thread W released from the fixed drum D, the arrangement positions of the light emitting element], ], a and the light receiving element 11b are fixed compared to those on the locking pin. It is assumed that the front side of the drum D is selected as p. Light projecting element 11a
is, for example, a low power consumption light emitting diode or the like, and the optical axis from the light projecting element 11a reaches the light receiving element 11b through the small hole D5, and the light receiving element 11b receives this light. As the light receiving element 11b, a light emitting element]-
A phototransistor or the like that has sufficient sensitivity to the wavelength of light emitted from 1a and has a sufficiently fast response speed can be used.

The induction coil 12b is mounted on the circumferential surface D8 of the fixed drum D so as not to protrude from the circumferential surface D3. Further, the excitation coil 12a is disposed outside the fixed drum D and faces the induction coil 12b. A gap g exists between the excitation coil 12a and the induction coil 12b, and this gap g forms a yarn path for the yarn W that is wound on the stationary drum D and is unwound. It shall be set to the minimum dimension.

The excitation coil 12a is AC excited by an oscillator 13 (FIGS. 1 and 2), and a stabilizing circuit 14 built into the fixed drum D is provided between the induction coil 12b and the light projecting element 11a. It has been intervened. The output of the light receiving element 11b is outputted to the outside via an amplifier 15 as an unwinding signal S.

Even if the rotating shaft SH is rotated now, the fixed drum D remains stationary because its rotation is restrained by the permanent magnets MG, MG, . . . . Therefore, the yarn guide YG rotating together with the rotating shaft SH can wind and store the yarn W on the peripheral surface D3 of the fixed drum D. Moreover, the thread W wound on the fixed drum D in this way slides down from the oblique part DI to the parallel part D2,
Its unwinding is prevented by the locking pin K in the locking position.

If the locking pin K is driven to the unwinding position in this state, the yarn W is removed from the fixed drum D by a weft insertion member (not shown).
Each roll is unwound and can be used for weft insertion.

On the other hand, since the excitation coil 12a is AC excited by the oscillator 1-3, a voltage is generated in the induction coil 12b by electromagnetic induction. That is, it is assumed that the excitation coil 12a and the induction coil 12b form a transformer having a gap g.

The voltage generated in the induction coil 12b is stabilized by the stabilizing circuit 14 and supplied to the light projecting element 11a.
The light projecting element 11a projects an optical axis toward the light receiving element 11b. At this time, since the arrangement position of the light emitting element 11a and the light receiving element 11b is on the front side of the fixed drum D than the arrangement position of the locking pin, the thread W unwound by the locking pin K is crosses the optical axis for each turn, and therefore, the light projecting element 11a and the light receiving element 11b can form a transmissive optical sensor for the thread W. The amplifier 15 is
Since the unwinding signal S is generated by amplifying the yarn signal S1 from the light receiving element 11b, the locking pin All you have to do is return K to the locking position.

The oscillator 13 is connected to an excitation coil 12 that faces each other through a gap g.
In order to realize good power transfer between the induction coil 12b and the induction coil 12b, it is generally preferable to use a high frequency oscillator of several tens of kHz or more. Moreover, although the excitation coil 12a and the induction coil 12b are preferably coils with an iron core, one or both of them may be air-core coils.

The stabilizing circuit 14 is for stabilizing the output voltage of the induction coil 12b and making the amount of light emitted from the light projecting element 11a constant. Therefore, when lighting the light projecting element 11a with direct current, a suitable rectifier circuit and a direct current stabilizing circuit can be used in combination. Furthermore, when lighting the light emitting element 11a at a high frequency, if its operating frequency does not match the oscillation frequency of the oscillator 13, a combination of a frequency conversion circuit such as a transistor inverter and an AC stabilizing circuit may be used. If the operating frequency and the oscillation frequency match, a simple AC stabilizing circuit such as a level clipper can be used, for example.

Other Examples The light-receiving element 1], b may have a light-receiving surface 11b1 that is long in the circumferential direction of the fixed drone D (FIG. 3). Even if the fixed drum D may generate vibrations in the circumferential direction during its operation, the optical axis from the light projecting element 11a will be
It does not deviate from the light receiving surface 11b1 of the light receiving element 11b.

One of the excitation coil 12a and the induction coil 12b can be formed longer than the other in the circumferential direction of the fixed drum D (FIG. 4). Even if the fixed drum D vibrates in the circumferential direction, it is possible to minimize the change in the effective cross-sectional area of the exciting coil 12a and the induction coil 12b when they face each other, and to reduce the fluctuation in the output voltage of the induction coil 12b. Therefore, the internal configuration of the stabilizing circuit 14 can be significantly simplified or omitted.

The light projecting element 11a and the light receiving element 11b may be arranged on the front end surface of the fixed drum D (FIG. 5). The yarn W unwound from the fixed drum D is exposed to the light emitting element 1 for each turn.
Since the optical axis from 1a can be crossed, the operation can be performed in the same manner as in the previous embodiment.Moreover, since the thread W does not pass through the position of the small hole D5, the peripheral edge of the small hole D5 There is no risk of inadvertently damaging the surface.

Note that the fixed drum D may be a so-called split drum in which the circumferential surface D3 is formed by a plurality of rod-shaped members Da % Da . . . arranged in the generatrix direction (FIG. 6).

At this time, the small hole D5 through which the optical axis from the light projecting element 11a passes.
can utilize the gap Dg between the members Da, and the induction coil 12b can also be disposed within the gap Dg.

Furthermore, in a type in which the rod-shaped members Da, Da... are moved in the radial direction and the diameter of the effective winding of the fixed drum D is changed, the induction coil 12b is replaced by the excitation coil 1.2.
The surface facing a may be fixed to the side end surface of the rod-shaped member Da without protruding from the peripheral surface D3. Even if the effective winding of the fixed drum D is changed in diameter, the relative positional relationship between the circumferential surface D3 and the induction coil 12b can be kept constant. Easy to set up.

The light projecting element 11a1 and the light receiving element 11b can be arranged outside and inside the fixed drum D, respectively (FIG. 7). That is, the light projecting element 11a is driven by an appropriate drive circuit 19.
On the other hand, the thread signal S1 from the light receiving element 1b is transmitted to the induction coil 1 via the stabilized power supply circuit 16.
2b, and a suitable non-contact signal transmission means 18,
The signal is pulled out to the outside and input to the amplifier 1-5. However, here, the signal transmission means 18 is illustrated as being of a transformer type consisting of a secondary coil 18a and a secondary coil 18b facing the secondary coil 18a. The signal transmission means 18 is preferably a magnetic sensor type that is not affected by the thread W on the fixed drum D, and in addition to a transformer type, a Hall element or a magnetoresistive element may be used instead of the secondary coil 18b. may also be used.

In each of the above embodiments, the small hole D5 of the fixed drum D is
For example, it can be closed with a translucent member 21 such as a lens (see the same figure). A translucent member 2 that is constantly wiped by the thread W on the fixed drum D is placed on the front surface of the light emitting element 11a or the light receiving element 11b disposed inside the fixed drum D.
1 is arranged, the light emitting element 11a1 and the light receiving element 11b
There is no possibility that fluff or the like will be deposited thereon, and there is no possibility that the amount of light received by the light receiving element 11b will be unduly reduced.

In addition, in this invention, if the arrangement position of the light emitting element 11a1 and the light receiving element 11b is selected at a predetermined position on the rear side of the fixed drum D with respect to the locking pin K, the windings are stored on the fixed drum D. It can be used as is as a release sensor for detecting the amount of stored yarn W.

As described in detail, according to the present invention, light is stored in the fixed drum or released from the fixed drum by the light emitting element and the light receiving element which are arranged separately inside and outside the fixed drum. A transmission type optical sensor is formed for the yarn being sown, and an induction coil placed on the fixed drum side and an excitation coil placed outside the fixed drum are used to detect the light emitting element etc. placed inside the fixed drum. By supplying power, the unwinding signal obtained can easily ensure a necessary and sufficient signal-to-noise ratio, so even when using colored yarn, etc., stable operation can be maintained at all times. There are excellent effects that can be achieved.

[Brief explanation of the drawing]

Figures 1 and 2 show examples, Figure 1 is an overall configuration diagram,
Figure 2 is an electrical system diagram. FIG. 3 is an enlarged sectional view of main parts showing another embodiment. FIGS. 4 to 6 each show a third embodiment showing another embodiment.
FIG. 2 is an enlarged sectional view of a main part corresponding to the figure. FIG. 7 is an electrical system diagram showing still another embodiment. W... Thread Sl... Thread signal D... Fixed drum D3... Circumferential surface g... Gap 11a... Light emitting element 11b... Light receiving element 12
a... Excitation coil 12b... Induction coil 14.
... Stabilization circuit 17 ... Signal processing circuit 18 ... Signal transmission means 2
1... Translucent member

Claims (1)

[Scope of Claims] 1) A light emitting element disposed inside the fixed drum so that the thread unwound from the fixed drum crosses the optical axis; A light-receiving element that receives light from the optical axis, an induction coil mounted on the circumferential surface of a fixed drum, and an excitation coil disposed outside the fixed drum and facing the induction coil through a gap serving as a yarn passage, The unwinding sensor for a fixed drum type weft length measuring and storage device, wherein the light projecting element is powered by the output of the induction coil. 2) The unwinding sensor for a fixed drum type weft length measuring and storage device according to claim 1, characterized in that a stabilizing circuit is interposed between the induction coil and the light projecting element. 3) The fixed drum type weft length measuring and storage device according to claim 1 or 2, wherein a translucent member that is wiped away by a thread is attached to the front surface of the light projecting element. unwinding sensor. 4) A light emitting element disposed outside the fixed drum so that the thread released from the fixed drum crosses the optical axis; and a light receiving element disposed inside the fixed drum and receiving light from the optical axis from the light emitting element. and an induction coil mounted on the circumferential surface of a fixed drum, and an excitation coil disposed outside the fixed drum and facing the induction coil through a gap serving as a thread passage, and receiving a thread signal from the light receiving element. via a signal processing circuit powered by the output of the induction coil and a contactless signal transmission means,
An unwinding sensor for a fixed drum type weft length measuring and storage device, which is drawn out to the outside of the fixed drum. 5) The unwinding sensor for a fixed drum type weft length measuring and storage device according to claim 4, characterized in that a translucent member that is wiped away by the thread is attached to the front surface of the light receiving element.