US3631901A

US3631901A - Photoelectric weft-bobbin feeler for looms for monitoring the yarn stock on weft bobbins

Info

Publication number: US3631901A
Application number: US33114*A
Authority: US
Inventors: Erwin Langenbach; Jurgen Erdmann
Original assignee: Erwin Sick GmbH Optik Elektronik
Current assignee: Erwin Sick GmbH Optik Elektronik
Priority date: 1969-03-14
Filing date: 1970-03-12
Publication date: 1972-01-04
Anticipated expiration: 1989-01-04
Also published as: FR2042727A5; BE747090A; GB1305424A; DE1912913A1; CH509443A

Abstract

The bobbin and/or shuttle are provided with light-responsive conditions such that two types of reflective light responses are created by a single-incident light beam. The two responses are received by two separate light detectors and a correctional signal is produced only if the two detectors simultaneously produce output signals.

Description

United States Patent [51] im. Cl

[72] Inventors Erwin Llnlenboch; 003d 45/12 Jul-gen Erdmann, both 01 Waldklrcla 1m [50] Field of Search 139/273 R, Brellpu, Germany 273 A, 370; 250/219 R, 219 DF, 219 S [21] Appl. No. 33,114 [22] Filed Mar. 12, 1970 References Cited [45] Patented Jan. 4, 1972 FOREIGN PATENTS Asslsnee 2 3am my 420,000 3/1967 Switzerland 139/273 A 9 [32] Pri ri y M". 1969 1,292,613 3/1962 France 139/273 A [33 1 Primary Examinerl-1enry S. Jaudon [31] P 19 12 9135 Attorney-Darbo, Robertson & Vandenburgh 54] PHOTOELECTRIC WEFFBOBBIN FEELER you #1 ACT: The bobbin and/or shuttle are provided with LOOMS FDR MONITQRING THE YARN g'g'acg light-responsive conditions such that two types of reflective 0N WE" ROBBINS light responses are created by a single-incident light beam. 11 Claims, 3 Drawing Figs. The two responses are received by two separate light detectors and a correctional signal is produced only if the two detectors n 3 f simultaneously produce output signals.

PATENTEU JAN 4 B72 3.631.901 SHEET 1 BF 2 ERWW LANG'ENBAC JZ/RGEN ERDMANN IN V EN TOR5 SHEET 2 [IF 2 Fig. 3

R1 LANGENBACH I JUAGEN ERDMA NN v INVENTORS 5% &

PHOTOELECTRIC WEI'T-BOBBIN FEELER FOR LOOMS FOR MONITORING THE YARN STOCK ON WEFT ROBBINS BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to improvements in a photoelectric weft bobbin feeler for looms for monitoring the yarn stock on weft bobbins comprising: first means for scanning the surface of the weft bobbin by the use of a scanning light beam, second means for affecting said scanning light beam mounted on said surface, said second means becoming exposed to reflections from said light beam when said yarn stock is drawn near the end, and third means for producing a first signal indicative of the approximately empty" state of the bobbin responsive to said first afi'ecting means being exposed.

In looms or automatic looms, it is necessary to monitor the yarn stock on the weft bobbin continuously during the weaving process. As soon as the yarn stock on a weft bobbin approaches the end, a corrective signal is produced which either initiates the automatic change of the bobbin or stops the loom. Photoelectric weft-bobbin feelers have been provided to fulfill these requirements. There are substantially two types of such photoelectric weft-bobbin feelers:

In one type of photoelectric weft-bobbin feeler, light-modulating devices are affixed to the surface of the weft bobbin. These devices become exposed as the yarn stock approaches the end. A light beam directed to the surface of the weft bobbin impinges upon the light-modulating device. The reflected modulated light beam falls on a photoelectric detector and initiates appropriate operations such as the change of bobbins or stopping of the loom. The light-modulating device can, for example, be a pattern of alternating colored rings comprising contrasting colors, one ring absorbing light and the next one reflecting it. Since the light is modulated, it will. produce an altemating-current-type electrical signal upon being received by the photoelectric detector, which signal is used for the control of further operations (see German Pat. No. 850,730).

A second type of photoelectric weft-bobbin feeler comprises a ring of reflex-reflecting substance or layer on the surface of the weft bobbin. Again a light beam is directed to the weft bobbin. When the weft bobbin is approximately empty, nearly all of the incident light beam is reflected back into the direction of incidence or into a small scattering angle thereabout. This reflected beam falls on a photoelectric detector and initiates appropriate operations (see German specifications 1,056,856 and 1,162,297 and US. Pat. No. 3,053,137).

The prior art photoelectric weft bobbin feelers mentioned above suffer from certain disadvantages.

When the shuttle with the weft bobbin is moved past the scanning light beam, a spurious light modulation can be effected by some other sequence of light and dark spots, such as the light surface of the weft bobbin and dark yarn. In this case, the first-mentioned type of weft-bobbin feeler will produce a false signal.

Furthermore, accidental reflexes can occur with the second-mentioned type of wefi bobbin feelers such as reflexes from glossy spots of the loom or the shuttle or from the yarn material itself (for example in the weaving of brilliant silk), and these reflexes will cause false signals.

Therefore, it is an object of the invention to provide an improved photoelectric weft-bobbin feeler. Another object of the invention is to provide a photoelectric weft-bobbin feeler which will not produce false signals due to causes other than the yarn on the bobbin being drawn near the end. A more specific object of the invention is to provide a photoelectric, weft-bobbin feeler, in which neither unwanted light-beam modulation not due to modulating means on the bobbin nor spurious reflexes will cause a corrective signal for initiating a change of bobbin, stop of the loom or the like.

in accordance with the invention this is achieved by second means for affecting a scanning light beam, mounted on the said second affecting means being also scanned by a scanning light beam at the same time as the said first affecting means, second signal-producing means for producing a second signal indicative of the moment or period of time in which the bobbin is to be scanned and means for initiating control operations responsive to said first and second signals from said first and second signal-producing means. To put it another way: a light beam is directed toward the bobbin which beam is divided into two components. One component is coded to indicate whether or not the bobbin is approximately empty. The second component is coded in a different manner to signify the proper time for reading the first component. The coding can be by pulsing the beam or by the position of the component when reflected.

The particular advantages achieved'by the invention are that accidental reflexes similar to those occurring during the scanning of the empty bobbin surface cannot cause false correction signals, as reflex signals become effective only in conjunction with a signal indicating that the bobbin surface is being scanned.

In one embodiment of the invention, said scanning means are adapted to produce one single light beam for scanning both said light-affecting means, and said affecting means are adapted to afl'ect said light beam in different ways so as to produce two signals discernible from each other.

Thus, the required optical apparatus is not much more than in the prior art devices, i.e., only one scanning light beam is required. This single light beam can, for example, be modulated in difi'erent ways by the two afi'ecting means. The modulated output signals from a single photoelectric detector, on which the modulated scanning light beam falls, can be separated by appropriate electronic circuits.

Also, the signals can be separated optically. This is done in an embodiment of the invention, wherein said single scanning light beam is directed to said two afi'ecting means at an acute angle, the first affecting means being adapted to regularly reflect said light beam to a first photoelectric detector, the second affecting means being adapted to reflect said light beam back into its direction of incidence to a second photoelectric detector. The output signals of said first and second detectors are then applied to an AN D-gate to produce a correction signal when they coincide. This embodiment of the invention offers the particular advantage that the separation of the two signals is effected in simple manner by making use of optical laws; the additional apparatus, as compared to the prior art, being little more than one additional photoelectric detector.

A specific embodiment of the invention is a photoelectric weft-bobbin feeler, wherein the surface of the bobbin (mounted in the shuttle) is scanned by the incident light beam through an elongated aperture in the shuttle, wherein below said aperture specularly reflecting and light-absorbing rings are provided on the surface of the bobbin and alternating in fore-and-aft direction thereof, and wherein a reflex-reflector is attached to the shuttle adjacent and along said aperture, the scanning light beam having elongated cross section to scan over the rings and the reflex-reflector at the same time. Thereby a simple arrangement is obtained which can be used easily in conventional looms. Further advantages are achieved, by using alternating reflecting and light-absorbing rings. Thereby the scanning light beam is modulated and the photoelectric detector produces an altemating-current (AC)- type signal. This signal is fed to a dynamic AC amplifier, whereby all false actuations resulting from yarn reflexes will be eliminated.

An AC signal that can be evaluated reliably will be produced even by one reflecting and one adjacent light-absorbing ring. In this case, the AC signal" occurring during the scanning will be a step signal caused by the line of contrast between the rings.

When reflecting yarn is being processed on a loom, the contrast step can be obtained by making the bobbin surface dark,

weft bobbin or on elements (shuttle) receiving said bobbin, i.e., light-absorbing. When a portion of the last layer of yarn has been drawn from the bobbin, the contrast step occurs when the beam scans from the bobbin surface to the remaining yarn. The same situation will occur if dark yarn is to be processed and the bobbin surface has been made reflecting.

DESCRIPTION OF DRAWINGS FIG. 1 schematically illustrates a portion of a shuttle, the weft bobbin and the photoelectric feeler at the moment of the scanning of the bobbin and shuttle;

FIG. 2 shows a portion of the shuttle and the aperture through which the bobbin is viewed; and

FIG. 3 is a block diagram of the electronic evaluation circuit.

DESCRIPTION OF SPECIFIC EMBODIMENTS The following disclosure is ofl'ered for public dissemination in return for the grant of a patent. Although it is detailed to ensure adequacy and aid understanding, this is not intended to prejudice that purpose of a patent which is to cover each new inventive concept therein no matter how others may later disguise it by variations in form or additions or further improvements. The claims at the end hereof are intended as the chief aid toward this purpose, as it is these that meet the requirements of pointing out the parts, improvements, or combinations in which the inventive concepts are found.

Referring to FIG. 1, reference numeral 1 designates the photoelectronic feeler device. A light beam, emitted from light source 2, .is collimated by a lens 3. It then is directed through partially transparent (beam-splitting) mirror 4 to the weft bobbin 9 and a reflex-reflector 13. The light beam reflected by the reflex-reflector 13 back along its path of incidence is deflected by the partially transparent mirror 4. The deflected portion reaches photoelectric detector 6 through lens 5. Another portion of the light beam passes through aperture 12 (at one side of the reflex-reflector 13). This portion strikes the weft bobbin 9. This portion of the light beam is specularly reflected from the surface of the weft bobbin (when there is no more yarn on the bobbin) and reaches photoelectric detector 8 through a lens 7.

Reference numeral 11 designates the wall of the shuttle in which the weft bobbin 9 is mounted. It has the aperture 12 through which a portion of the light beam gets to the weft bobbin 9. Reference numeral designates a thread wound on the weft bobbin. When the yarn stock on the bobbin 9 approaches the end, black and white varnished rings 14 and 15, respectively, become visible to the incident beam. By the sequence of a light-absorbing and specularly reflecting ring, the scanning light beam will detect the contrast step (when the yarn stock on the bobbin is at or approaching the end). The portion of the beam reflected to detector 8 will be pulsed to pulse the electrical output of the detector.

FIG. 2 illustrates, how the reflex-reflector 13 is positioned on the shuttle wall adjacent the aperture 12. The weft bobbin would be behind this aperture 12. The light beam 16 has an elongated cross section, as shown in dotted lines. This elongation is transverse to the direction of movement of the shuttle so that the reflex-reflector I3 and the surface of the weft bobbin are scanned simultaneously.

FIG. 3 illustrates, in principle, how the output signals from the two

detectors

6 and 8 are evaluated. The output signals are applied to an AND-gate 19 through two amplifiers l7 and 18. The output signal of the AND-gate is a correction signal to control (in a well-known manner not shown) further operations. For example, this correction signal initiates the automatic change of the bobbin. The correction signal from the AND-gate is produced only from

detectors

6 and 8 if both signals are present. The amplifier 18 produces an output signal to the AND-gate only if the input signal from the photoelectric detector 8 is of the alternating current type, i.e., it amplifies only AC signals or step signals.

The reflex-reflector 13 shown in FIG. 2 may be a layershaped, reflex-reflecting substance or a strip on which a plurality of small triple reflectors are arranged closely side-byside.

We claim:

I. In the process of detecting and actuating a corrective signal in response to an approximately empty situation of a bobbin member carried by a shuttle member of a loom wherein said situation is detected by a given condition of said bobbin member being present, the improvement comprising the steps of:

checking to determine if a particular condition of one of said members is present;

at the same time making said check for said given condition;

and

initiating said corrective signal only when said conditions exist simultaneously.

2. In the process of claim I, wherein a light beam is directed towards said bobbin member;

said light beam is divided into two components;

one of said components being coded in a predetermined fashion if said situation is present; and

said other component being coded in another fashion in response to said particular condition being present.

3. In an apparatus for detecting and initiating a corrective signal in response to an approximately empty situation of a bobbin member carried by a shuttle member of a loom wherein a first means senses a given condition of said bobbin member as indicative of said situation to produce a first output signal, the improvement comprising:

second means for checking one of said members for the existence of a particular condition at each instant and for producing a second output signal when said particular condition exists on the one member; and

third means connected to the first two means to initiate said corrective signals upon the simultaneous occurrence of the first and second output signals.

4. In an apparatus as set forth in claim 3, wherein said first and second means include a common device for producing a single light beam directed at said members and separate respective light detectors, said conditions affecting said light beam in different ways to produce two separate reflective light responses, said detectors being positioned to receive said light responses respectively.

5. In an apparatus as set forth in claim 4, wherein said conditions are a single identical condition which simultaneously produces said two separate reflective light responses.

6. In an apparatus as set forth in claim 4, wherein said single light beam is directed at said conditions at an acute angle, said given condition reflecting said light beam to the detector of the first means, said second means including a partially reflective mirror in the path of the single light beam, said particular condiu'on including reflective means for reflecting some light from said single beam back into its direction of incidence to said mirror and the detector of the second means, said third means including an AND-gate.

7. In an apparatus as set forth in claim 6, wherein said shuttle member has an elongated aperture through which the bobbin member is viewed by said single light beam and a reflex reflector at one side of said aperture, and the portion of said bobbin member so viewed by said light beam has light-reflecting and light-absorbing rings alternating in the fore-and-aft direction thereof.

8. In an apparatus as set forth in claim 7, wherein the detector of the first means produces an alternating-current-type electric signal, and said first means includes an amplifier which will amplify only altemating-current-type signals.

9. In an apparatus as set forth in claim 7, wherein said rings are white and black varnished rings.

I0. In an apparatus as set forth in claim 3 for use with a light-reflective yarn, wherein the bobbin member has a lightabsorbing surface.

11. In an apparatus as set forth in claim 3 for use with a light-absorbing yarn, wherein the bobbin member has a lightreflective surface.

Claims

1. In the process of detecting and actuating a corrective signal in response to an approximately empty situation of a bobbin member carried by a shuttle member of a loom wherein said situation is detected by a given condition of said bobbin member being present, the improvement comprising the steps of: checking to determine if a particular condition of one of said members is present; at the same time making said check for said given condition; and initiating said corrective signal only when said conditions exist simultaneously.

2. In the process of claim 1, wherein a light beam is directed towards said bobbin member; said light beam is divided into two components; one of said components being coded in a predetermined fashion if said situation is present; and said other component being coded in another fashion in response to said particular condition being present.

3. In an apparatus for detecting and initiating a corrective signal in response to an approximately empty situation of a bobbin member carried by a shuttle member of a loom wherein a first means senses a given condition of said bobbin member as indicative of said situation to produce a first output signal, the improvement comprising: second means for checking one of said members for the existence of a particular condition at each instant and for producing a second output signal when said particular condition exists on the one member; and third means connected to the first two means to initiate said corrective signals upon the simultaneous occurrence of the first and second output signals.

6. In an apparatus as set forth in claim 4, wherein said single light beam is directed at said conditions at an acute angle, said given condition reflecting said light beam to the detector of the first means, said second means including a partially reflective mirror in the path of the single light beam, said particular condition including reflective means for reflecting some light from said single beam back into its direction of incidence to said mirror and the detector of the second means, said third means including an AND-gate.

8. In an apparatus as set forth in claim 7, wherein the detector of the first means produces an alternating-current-type electric signal, and said first means includes an amplifier which will amplify only alternating-current-type signals.

10. In an apparatus as set forth in claim 3 for use with a light-reflective yarn, wherein the bobbin member has a light-absorbing surface.

11. In an apparatus as set forth in claim 3 for use with a light-absorbing yarn, wherein the bobbin member has a light-reflective surface.