EP0837829A2

EP0837829A2 - Optoelectronic sensor and weft yarn measurement and feeding equipment

Info

Publication number: EP0837829A2
Application number: EP96923976A
Authority: EP
Inventors: Henrik Lilja
Original assignee: Picanol NV; Iro AB
Current assignee: Picanol NV; Iro AB
Priority date: 1995-07-11
Filing date: 1996-07-05
Publication date: 1998-04-29
Anticipated expiration: 2016-07-05
Also published as: KR19990028680A; JPH10511069A; US5966211A; CN1084285C; KR100293027B1; JP2915147B2; CN1190379A; DE59603233D1; WO1997003012A1; EP0837829B1; DE19525260A1

Abstract

An optoelectronic sensor (S) for detecting a weft yarn passing through a scanning zone (3) has at least one light source (L, L'), at least one photoelectric receiver (R1, R2) that is sensitive to variations in light intensity and is connected to an evaluation circuit (C), and a slitted diaphragm (A1, A2) arranged between the yarn and the receiver. In a weft yarn measurement and feeding equipment (F), the sensor (S) detects overend unwinding of the thread from the feeding body (B). At least two receivers (R1, R2) arranged next to each other are oriented towards the scanning zone and their receiving surfaces (4, 5) are covered by a slitted diaphragm (A1, A2), with the exception of a limited area. The slitted diaphragms (A1, A2) are arranged at an acute angle of maximum 90° in relation to each other.

Description

Optoelectronic sensor device and weft measuring storage device

The invention relates to an optoelectronic sensor device according to the preamble of patent claim 1 and to a weft thread measurement storage device according to the preamble of patent claim 4.

In the case of an optoelectronic sensor device known from GB-C-1 283 528, the transverse passage of a spun thread is detected in a ring spinning machine, the running thread rotating in an opening. The opening is penetrated by a light beam which a light source arranged in an opening wall throws diametrically through the opening onto an opposite receiver. An aperture slit is provided in front of the receiver. The receiver responds to light variations or the shadow of the thread passing through the aperture slit. Interferences such as vibrations, extraneous light and the like can cause the receiver to emit an error signal, even though the thread has not properly passed the aperture slot in the scanning zone.

In weft measuring storage devices, as have typically been used for a long time on jet looms to provide the weft, exact information is required to control and monitor the insertion process of each weft when and that the weft passes a scanning zone when it is drawn off. For this purpose, at least one trigger sensor is provided, which is equipped with a receiver which is aligned with the illuminated scanning zone and responds to light variations. Since, in practice, operational vibrations, the influence of ambient light and other disturbances cause the receiver to respond, the meaningfulness of the signals obtained from the passages of the weft thread is unreliable. In practice, therefore, one has gone over to aligning two receivers arranged closely behind one another in the axial direction of the storage body on the same scanning zone. and from the response of the two receivers in a differential circuit to derive a meaningful signal for the thread passage, which can therefore be distinguished from signals caused by interference, because an interference effect on both receivers acts simultaneously and in the same way, while the thread of the both recipients with a time delay is registered. Nevertheless, this known scanning sensor does not work reliably with the two receivers for several reasons. The receiver surface of each receiver is usually approximately circular. The thread moving relative to the receiver surface is only gradually reproduced with its reflection light or shadow due to the circular shape of the receiver surface. In addition, the response sensitivity of the receiver is weaker in the edge areas of the receiver surface than near the center. The signal evaluated in the differential circuit is therefore weak because of the gradual increase in signal and the gradual decrease in signal and requires considerable amplification, which is also effective in the event of interference. Furthermore, in such measuring storage devices a clearly aixal back and forth movement of the withdrawal-side limit of the thread supply present on the storage body is indispensable, especially when working with thread separation and / or a lively pattern is being woven. This results in a thread take-off geometry in which the longitudinal direction of the thread in the thread drawn off from the last turn of the thread supply in the scanning zone varies between an approximately axial position and an approximately circumferential position, in each case based on the axis of the storage body. In the case of an approximately axial position of the longitudinal direction of the thread in the scanning zone, the thread is perceived by both receivers at the same time and in the same way, which complicates or precludes discrimination against disturbing influences which are likewise perceived simultaneously and equally at both receivers. The invention has for its object to provide a simple opto-electronic sensor device of the type mentioned and a weft thread measuring storage device, in which a strong and meaningful and easily discriminatable against signals from interference can be generated from the thread passage useful signal. In the case of the measuring memory device, the pull-off sensor is intended to provide exact information, when and that the thread is passing through the scanning zone, in spite of varying thread pull-off speed, different thread qualities and changing position of the thread longitudinal direction in the scanning zone.

The term thread generally refers to thread-like substrates such as yarns, threads, threads, spun threads, wires, tapes, film strips and the like.

However, complex optoelectronic sensor devices whose receivers work with imaging or sharp imaging of the object to be scanned and which require position-sensitive detectors, imaging optics and high-quality circuits are expressly excluded. Such sensor devices are too complex and expensive for the scanning of a thread passage by themselves or in a measuring memory device and are also ruled out of use for other reasons (e.g. WO 89/00215, EP-A-1 052 9281).

The object is achieved in an optoelectronic sensor device with the features of claim 1 and in a weft thread measuring device with the features of claim 4.

In the optoelectronic sensor device and in the weft thread measurement storage device, a particular advantage in the scanning of each thread passage is an exact, meaningful, powerful and easily usable signal that can be discriminated against by signals due to interference, namely with structurally and in terms of circuit technology low and inexpensive. The position of the longitudinal direction of the thread in the scanning zone no longer plays a role, since the thread passes the two diaphragm slots at different times or in different geometries, so that the differential evaluation of the response of both receivers always leads to a clear signal, which is based on a signal of a disturbing influence clearly distinguishes, because the disturbing influence is recorded in the same time and geometrically at both receivers. Furthermore, a strong modulation of the signal is achieved from the thread passage in the scanning zone because, on the one hand, the less sensitive edge areas of the receiver surfaces are covered and do not come into effect, and on the other hand, the thread in each aperture slot (with its reflection light or its shadow) is extremely fast with it full size becomes visible. Since the time that elapses before the thread is fully imaged on the area of the receiver area narrowed by the aperture slit is extremely short, as is the time until the complete image completely disappears, the signal generated by a differential evaluation contains a strong and low amplification effort Frequency components which can be tapped off and which are not present in the case of a signal resulting from an interference. In summary, the use of two receivers, two diaphragm slots and the geometrical arrangement of the diaphragm slots, regardless of the position of the longitudinal direction of the thread in the scanning zone, the strength and frequency of interferences, and also largely independent of contamination, result in a strong and meaningful statement Signal from a thread passage, which can be further processed with little circuitry. Simple and inexpensive receivers are used which respond to light variations. The gentle response behavior of these receivers is unexpectedly exacerbated by the aperture slit when the thread passes properly. The receivers can be placed close to one another. This beneficial result is achieved to the highest in guarantees modern thread processing systems usual thread speeds. More than two receivers, each with one aperture slit, are also conceivable.

In the embodiment according to claim 2, the critical edge regions of the receiver surface, which are sensitive to the response behavior to light variations, are covered. However, it is also conceivable to design the aperture slit as long as or even longer than the diameter of the receiver surface.

In the embodiment according to claim 3, the useful signal is generated from the addressing of the two receivers in the evaluation circuit designed as a differential circuit.

In the embodiment according to claim 5, a compact design of the draw-off sensor can be achieved, the draw-off sensor being practically independent of the speed variations of the thread moving through the scanning zone and, above all, independent of the respective position of the thread longitudinal direction in the Scan zone is.

The embodiment according to claim 6 is particularly expedient. It is ensured here that the thread from both receivers only in areas and areas of the receiver areas limited by the diaphragm slots and regardless of the position of the longitudinal direction of the thread in the scanning zone in terms of time and / or geometry is perceived differently.

A particularly expedient embodiment is evident from claim 7. It is expedient if the crossbar T maintains a small distance from the thigh, so that there is an asymmetry in the scanning of the thread via the geometric configuration of the diaphragm slots, which is important for distinguishing between useful and interference signals and for a strong useful signal . With the forms of the diaphragm slots specified in claim 8, it is ensured that the full exposure to light or shading of the areas of the receiver surface occurs very quickly or stops quickly in order to achieve the greatest possible frequency component for the useful signal.

Diaphragm slots of the same size are advantageous.

The embodiment according to claim 10 is particularly important. With this coordination of the positions of the diaphragm slots to the possible positions of the longitudinal direction of the thread in the scanning zone, it is excluded that the thread is perceived geometrically or temporally in the same way by both receivers.

In the embodiment according to claim 11, a compact, functionally reliable and reliable design of the trigger sensor is possible. The holder with its channels, the receivers, the light source and the aperture slots is a simple and inexpensive component that can be prefabricated with high precision, which can be accommodated cheaply and easily exchanged even in confined spaces.

In the embodiment according to claim 12, the components are combined in the smallest of spaces.

In the embodiment according to claim 13, the cover disk prevents contamination or dusting of the components arranged in the holder.

The distance dimensioning according to claim 14 has proven to be advantageous. Finally, in the embodiment according to claim 15, the respective position of the or the relative position between the diaphragm slots is adjustable or adjustable.

Embodiments of the subject matter of the invention are explained with the aid of the drawing. Show it:

1 is a schematic plan view of a sensor device,

2A, B side views, partly in section, of the sensor device of Fig. 1,

3 shows a schematic representation of a sensor device designed as a take-off sensor of a thread delivery device,

4 shows a selection of possible shapes for the diaphragm slots which can be used in FIGS. 1, 3 and 7,

5A is a side view of a weft thread measuring device,

5B is a front view belonging to FIG. 5A,

Fig. 6 is a longitudinal section of a detail of Fig. 5A, and

7 is a bottom view of FIG. 6.

1 schematically illustrates the structure of an optoelectronic sensor device S for determining the passage of a thread Y which also moves transversely to its longitudinal direction D (for example in the direction of the arrow 1) through a scanning zone 3. In addition to the movement in the direction of the Arrow 1 can the thread Y can also be moved in the direction of arrow 2, ie in its longitudinal direction D. The scanning zone S is a spatial area which is illuminated by at least one light source L and on which two receivers R1, R2 with their receiver surfaces 4 and 5 are aligned in the embodiment shown. Instead of the light source L offset in the direction of the receivers R1, R2, a central light source L 'could be provided either on the side of the receivers or on the side opposite the receivers. An aperture slit AI or A2 is provided in front of the receiver surface 4 or 5 of each receiver R1, R2, specifically in the beam path between the thread Y or the scanning zone 3 and each receiver surface 4 or 5. The two aperture slits AI and A2 are, for example, of the same size, have the same geometric configuration and each have a cross-sectional main axis 6 and a secondary axis 7 perpendicular thereto. The diaphragm slots AI, A2 are approximately 1, for example, with a length of approximately 4 mm mm wide. 1, the diaphragm slot A2 is aligned with its main axis 6 to the main direction defined by the two receivers R1, R2, while the diaphragm slot AI runs perpendicular thereto, with an extension of the diaphragm slot A2 cutting the diaphragm slot AI approximately in the middle ¬ det. Both diaphragm slots AI, A2 could also be twisted relative to each other, but it is important that they form an acute angle with one another up to a maximum of 90 °.

2A and 2B illustrate the side views of two embodiment variants of the sensor device according to FIG. 1. In FIG. 2A, the light source L and the two receivers R1, R2 are located on the same side of the scanning zone 3, below which an element 8 is located, which is designed either as a reflector or as a light absorber. A passage gap for the thread Y is defined between the element 8 and an at least partially transparent cover 10. The light source L and the two receivers R1, R2 are mutually taking into account certain light reflection angles aligned. Both receivers R1, R2 are aligned with the scanning zone 3 illuminated by the light source L and are acted upon by the reflection light. Each receiver R1, R2 is preceded by an aperture slot AI, A2, for example in an aperture element 9.

If the sensor device S operates according to FIG. 2A according to the reflection principle, then when the thread Y passes through, the light reflected by the element 8 is shaded in accordance with the outline of the thread Y. Each receiver R1, R2 responds to the light variation. Both receivers R1, R2 are connected to an evaluation circuit C (FIG. 2B), which operates according to the differential principle and generates a useful signal from the difference in the photoelectric response signals of the receivers R1, R2.

On the other hand, if the element 8 absorbs the light from the light source L, then the receivers R1, R2 respond to the light reflected by the thread Y.

The sensor device S according to FIG. 2B works according to the light barrier principle, ie the light from the light source L 'passes through the scanning zone 3 and strikes the receivers R1, R2 which, when the thread Y passes through, shadows according to the outline of the thread Y. become.

Assuming that the receivers R1, R2 of FIG. 2A or FIG. 2B are matched to the light coming from the light source L, in the absence of the thread Y, the area of the receiver surfaces 4, delimited by the aperture slots AI, A2, 5 fully loaded with light. In the evaluation circuit C, the difference between the response signals of the two receivers R1, R2 gives the value zero or a constant signal value (for example a voltage value). If the thread Y passes the scanning zone 3 in the direction of the arrow 1, then the area delimited by the aperture slit AI is first on the receiver surface. Before 4 of the receiver R1 is at least partially shaded, and later the area delimited by the aperture slot A2 on the receiver surface of the second receiver R2. When the thread Y moves in the direction of arrow 1, the thread Y has already left the aperture slot AI while it is still moving through the aperture slot A2. The period of time, starting with the intersection of the outline of the thread Y with the aperture slit AI or A2, up to the point in time at which the outline of the thread Y is greatest for the aperture slit AI or A2 is extremely short, which has the advantage of a strong frequency component of the response signal and thus a strong modulation. This also applies to the movement of the contour of the thread Y out of the area of the aperture slit AI or A2, so that a strong frequency component for an effective modulation then also arises. Since the thread Y for the two receivers R1, R2 or their restricted areas on the receiver surfaces 4, 5 moves differently in terms of time and geometry, a difference is determined in the evaluation circuit C during the thread passage, from which a powerful useful signal is obtained can be derived. Thanks to the strong frequency components and good modulation, the useful signal is meaningful and can be used for further processing with little amplification. Due to the arrangement of the diaphragm slots AI, A2, the sensor device S is insensitive to changes in the position of the longitudinal thread direction D in the scanning zone 3 and relative to the direction in which the receivers R1, R2 lie next to one another.

If, due to a disturbing influence (vibrations, extraneous light and the like), the two receivers R1, R2 are acted upon, response signals can likewise result. However, since this loading takes place in the same time and geometrically, it is possible at any time to distinguish between real and incorrect useful signals and to only derive and process the real useful signals from the thread passages. 3, the sensor device S is a take-off sensor of a thread delivery device, which carries a thread supply 13 of several, preferably axially spaced, thread turns on a storage surface B, from which the thread Y passes over a take-off edge 12 in the direction of an arrow 2 is withdrawn, whereby the thread Y rotates in the direction of arrow 1 and passes through the receivers R1, R2 with their front diaphragm slots AI, A2. The limit of the thread supply 13 lying at the front in the draw-off direction is indicated by 14. In the operation of such a delivery device, the axial position of the limit 14 varies considerably (double arrow 15). The result of this is that when the thread is drawn off, the longitudinal direction D of the thread in the region of the receivers R1, R2 can also vary between an almost axial position and an almost circumferentially oriented position. This is indicated by the arrows D. Despite this variation in the position of the longitudinal direction D of the thread in the scanning zone of the sensor device, a meaningful useful signal is obtained as a display from a thread passage, mainly because of the arrangement of the two diaphragm slots AI, A2 which are oriented at an acute angle to one another. that a thread turn has been withdrawn and when it was withdrawn.

3, the diaphragm slots AI, A2 are arranged in the shape of a T, the crossbar of the T being adjacent to the trigger edge 12 and being aligned in the circumferential direction.

Dotted lines also indicate that an opposite arrangement of the aperture slots AI, A2 is also possible, or even (indicated on the left and dashed lines) that the two aperture slots AI, A2 are inclined with respect to the trigger edge 12 running in the circumferential direction.

In all embodiments, the aperture slits AI are shorter than the diameter of the circular receiver surface. of the receiver Rl, R2. However, it is also conceivable to design the diaphragm slots to be of the same length or even longer than the diameter of the receiver surfaces.

Fig. 4 illustrates schematically a selection of possible shapes for the aperture slots AI, A2. A rectangular shape with the cross-sectional and main axis 6 and the cross-sectional and main axis 7, which is perpendicular to the cross-sectional main axis 6, is conceivable. It is also possible to shape the aperture slits AI, A2 oval, double concave or double convex, in each case with a view to ensuring that the outline of the thread to be detected is as quickly as possible in its full size above the aperture slit or the aperture slit leaves again as quickly as possible in order to effect a strong frequency component or a strong modulation for a strong useful signal.

5A, 5B show a specific embodiment of a weft thread measuring storage device F. These devices have been known for a long time and are used, for example, for delivering a weft thread to a jet loom, the measuring storage device F, in addition to the task of having a thread supply of sufficient size for the respective pattern available for drawing off, with the drawing tension being as constant as possible, also fulfilling the task limit the peelable weft length to an adjustable value. A drive shaft 16 is rotatably mounted in a housing 17, on which a storage body B, for example a rod drum or a rod cage 20 made of a plurality of axially extending rods 21 which are spaced apart in the circumferential direction, is in turn rotatably mounted. The storage body B is held stationary in that permanent magnets 25 arranged in the housing and in the storage body prevent the relative rotational movement of the storage body B relative to the housing 17. A winding arm 16a is attached to the drive shaft 16 and feeds it from the left side in FIG. 5 to the drive shaft 16, which is hollow Thread leads outwards to the storage area of the storage body B, where it is deposited in a rotation of the drive shaft 16 in successive turns in the supply 13 shown in FIG. 3. The free end of the thread runs over the draw-off edge 12 and is drawn off approximately coaxially to the drive shaft 16 by the textile machine or jet loom, not shown. A housing 23 is fastened to a housing bracket 18, below which a control device 19 is provided for driving the storage device F, in which, in addition to a stop device with a stop element 24, the optoelectronic sensor device S serving as a trigger sensor is accommodated. The thread is pulled under the housing 23. The stop element 24 is extended through a gap formed between the housing 23 and the adjacent rod 21 as soon as no thread may be drawn off. If, on the other hand, thread is required, the stop element 24 is withdrawn and the thread is pulled off. The sensor device S registers each drawn turn and transmits a useful signal representing the point in time and the occurrence of a passage to the control device 19, which engages the stop element 24 again before the thread length to be removed is reached. With an adjusting device V, the distance of the rods 21 from the axis of the device can be adjusted, and thus the length of each thread turn.

6 and 7, components of the sensor device S from FIG. 5 are indicated. A block-shaped holder 26, for example a molded plastic part, has a lower surface 27 facing the storage body B. Three channels 28, 29 and 30 open into the surface 27. The light source L is arranged in the channel 30. The receivers R1, R2 are provided in the channels 28 and 29. The diaphragm slots AI, A2 are formed in the mouths of the channels 28, 29 in the surface 27. Furthermore, a translucent cover plate 31 can be arranged on the surface 27. In the embodiment shown, all three channels 30, 28, 29 are arranged in the same axial plane 17 'of the storage body B. The channel 30 is positioned with respect to a radial plane on the drive shaft 16 with an angle α3 of approximately -27 °, while the channel 28 with an angle α2 of approximately + 22 ° and the channel 29 with an angle αl of approximately + 32 ° is inclined. The axes of all three channels aim in the scanning zone 3. The take-off sensor S is expediently arranged in the direction of rotation of the thread when the take-off is immediately adjacent to the stop element 24.

The aperture slots AI, A2 could be formed in aperture plates (indicated in FIG. 3), which can be adjusted in their rotational positions, e.g. in order, depending on the direction of rotation of the drive shaft or taking into account the respective thread geometry when pulling off, to be able to optimally coordinate the relative positions of the diaphragm slots AI, A2 relative to one another and with respect to the axis of the storage body. The two diaphragm slots AI, A2 could also be provided together in a diaphragm plate that can be rotated for tuning and has a fixed mutual assignment.

Claims

claims

1. Optoelectronic sensor device (S) for determining the passage of a thread (Y) moving transversely to its longitudinal direction (D) through a scanning zone (3), with a light source (L, L ') illuminating the scanning zone and at least one Receiver (Rl, R2) which responds to light variations and which is aligned with the scanning zone and which is connected to an electrical evaluation circuit (C) and with one between the thread (Y) and the receiver surface (4, 5) of the receiver arranged aperture slot (AI, A2), characterized ge indicates that at least two closely adjacent receivers (R1, R2) are aligned with the scanning zone (3), the receiver surfaces (4, 5) of which each have an aperture slot (AI, A2) that each aperture slot (AI, A2) has a geometric configuration with a long cross-sectional main axis (6) and a short cross-sectional secondary axis (7) perpendicular thereto, and that the aperture slots (AI, A2) with the Qu Section main axis (6) of one diaphragm slot (AI) are arranged at an acute angle of at most 90 ° transversely to the cross-sectional main axis of the adjacent diaphragm slot (A2).

2. Sensor device according to claim 1, characterized in that each receiver surface (4, 5) is approximately circular in the direction of light incidence, and that the length of the cross-sectional main axis of the front aperture slit (AI, A2) is shorter than the diameter of the receiver surface.

3. Sensor device according to claims 1 and 2, characterized ge indicates that both receivers (R1, R2) are connected together to the evaluation circuit (C) designed as a differential circuit.

4. weft measuring memory device (F) with an optoelectronic sensor device (S) as a withdrawal sensor of a rotating and weft thread (Y) removable from a storage body (B) overhead, the sensor device comprising at least two optoelectronic receivers (R1, R2) arranged one behind the other in the axial direction of the storage body (B), at least one light source (L) for illuminating a scanning zone (3) on the memory body, and has an electronic evaluation circuit (C) with which a useful signal can be generated each time the weft thread (Y) passes through the scanning zone (3) from light variations occurring at the receivers, characterized in that between an aperture slit (AI, A2) is provided in the scanning zone (3) and each receiver (R1, R2), and that one aperture slit (AI) is at an acute angle of up to maximum relative to the other aperture slit (A2) 90 ° is arranged.

5. Measuring memory device according to claim 4, characterized in that the one aperture slit (AI) extends in the circumferential direction and the other aperture slit (A2) in the axial direction of the storage body (B).

6. Measurement memory device according to claim 4, characterized in that an imaginary extension of an aperture slit

(A2) cuts the other aperture slot (AI).

7. Measuring memory device according to claim 5, characterized in that the two diaphragm slots (AI, A2) are arranged in the shape of a T.

8. Measurement storage device according to at least one of claims 4 to

7, characterized in that both aperture slots (AI, A2) have a rectangular, double concave or double convex shape.

9. Measurement memory device according to at least one of claims 4 to

8, characterized in that both aperture slots (AI, A2) are the same size.

10 measuring memory device according to at least one of claims 4 to 9, characterized in that the diaphragm slots (AI, A2) are arranged relative to all possible positions of the thread in the longitudinal direction (D) in the scanning zone (3) in such a way that a geometric or the same time movement of the thread (Y) through both aperture slots (AI, A2) is excluded.

11. Measuring memory device according to claim 4, characterized in that on the memory body (B) below the scanning zone (3) a reflector (8) is provided that in a housing (23) arranged in a stationary manner outside the memory body (B) has a block-shaped holder ( 26), which has a surface (27) facing the scanning zone (3), into which channels (28, 29, 30) aimed at the scanning zone (3) from at least one light source (L) arranged in the holder and from two receivers (R1, R2), preferably photodiodes, arranged in the holder, and that the mouths of the channels (28, 29) from the receivers (R1, R2) as aperture slots (AI, A2) with an approximately rectangular configuration are trained.

12. Measuring memory device according to claim 11, characterized gekennzeich¬ net that the channels (28, 29, 30) lie in a common Axiale¬ plane (16 ') of the memory body (B) that the channel (30) from the light source (L ) is inclined with respect to a radial plane (X) of the storage body (B) by approximately -27 °, and that one channel (28) from one receiver (R2) is below approximately + 22 ° and the other channel (29) from the other Receiver (Rl) are inclined at approx. + 32 ° to the radial plane.

13. Measuring memory device according to claims 11 and 12, characterized in that a translucent cover plate (31) is arranged on the surface (27) of the holder (26).

14. Measuring memory device according to claim 11, characterized in that the distance between the diaphragm slots (AI, A2) seen in the axial direction of the memory body (B) corresponds approximately to the width of each diaphragm slot (AI, A2).

15. Measuring memory device according to at least one of claims 4 to 14, characterized in that each aperture slit (AI, A2) or both aperture slits (AI, A2) is or are cut out in an aperture plate, with a selectable, preferably adjustable, rotational position in a socket, preferably in the surface (27) of the holder (26) or in the mouth of one of the channels (28, 29).