FR2588960A1 - TEXTILE MONITORING APPARATUS FOR RECORDING DEFECTS - Google Patents

Abstract

THE TEXTILE MONITORING DEVICE INTENDED TO RECORD FAULTS INCLUDES A SIGNAL ANALYSIS CIRCUIT WHICH IS CONNECTED TO AN OPTOELECTRIC CONTROL HEAD AND WHICH CONTAINS A MICROPROCESSOR31 WHICH DRIVES A TRIGGER 34 SIGNAL AMPLIFIER35 AND A TRIGGER 34 SIGNAL AMPLIFIER. SCANNING. THE INVENTION ALSO RELATES TO A PROCESS FOR AUTOMATICALLY CALIBRATING THE SIGNAL AMPLIFIER34 AND THE TRIGGER STAGE35 AS A FUNCTION OF THE LOWEST DEGREE OF REFLECTION OF THE FAULT-FREE TEXTILE.

Description

_ _ 2588960

  The present invention relates to a textile inspection device for recording defects, comprising at least one optoelectric control head, which operates on the principle of light reflection and which serves signal transmitter, and an electrical signal analysis circuit which includes a microprocessor and which provides output signals for controlling the

minus a switching device.

  Textile control devices with spray heads

  optoelectric controls are already known and have for example been de-

  written in patent DE-A-14 35 180. There is also known an apparatus for controlling textile fabrics with optoelectric control head, the signal analysis circuit of which includes a microcomputer (DE-A-31 33 428) . Known textile testing devices have

  a disadvantage, namely that it is necessary to adapt their sensi-

  bility in the fabric to be checked, which requires manual adjustment as-

  treignant, and / or they involve planning a complex arrangement

  of circuits to avoid coupling errors.

  The object of the present invention is to provide an apparatus for controlling textile fabrics of the type indicated above, which makes it possible to

  automatically adjust the sensitivity according to the degree of reflection

  xion of the textile yarn to be checked and of certain parameters of the textile yarn

  , and which therefore guarantees reliable reporting of faults.

  This object is achieved by means of a device for checking textile fabrics of the type indicated above, characterized in that the control head comprises at least one light source, which delivers

  known manner of light pulses at a predetermined rate-

  mined, and at least one corresponding optoelectric light receiver

  which detects the reflected light pulses delivered from

  in a clocked manner, and in that the signal analysis circuit

  linked to at least one light receiver comprises a signal amplifier

  which is controlled by the microprocessor and which has several

- 2 - -2588960

  amplification gain ranges, a trigger stage, which is

  controlled by the microprocessor and which has a trigger level

  ment adjustable as a function of the amplification gain of the signal amplifier, a fault signaling stage and at least one fault signaling analysis stage, these various elements being

  mounted one behind the other.

  The textile inspection apparatus in accordance with the invention

  tion can be calibrated automatically before the start of an operation

  control of faults. This calibration method according to the invention is characterized in that the signal amplifier is first adjusted, by the microprocessor, on the amplification range

  necessary to detect the weakest reflection signal

  falling during a predetermined calibration time or a predetermined relative movement path of the control head on a portion of the textile fabric free of defects, and in that the trigger level of the trigger stage is then shifted, via the microprocessor, by a preselected deviation below the sensitivity level of the signal amplifier, before the microprocessor returns to the fault signaling stage

operational.

  In the case of the textile checking device

  form of the invention and its operating process controlled by microprocessor, the necessary adjustment of the sensitivity of the control device is therefore carried out entirely automatically due to the difference in the degree of reflection of the textile webs to be checked, and a trigger level for sending a fault signal is adjusted automatically, so that signal variations,

  which necessarily appear when scanning a textile fabric

  designed with zones whose degrees of reflection are different

  annuities, do not trigger a fault signal, but only a signal

  fault is only triggered by holes and clears

  either from a defective mesh formation or an equivalent defect

slow.

  In addition, the reliability of the tex-

  tiles is improved by the special design of the cone head

- 3 - 2588960

  optoelectric gauge which can advantageously include several infrared light-emitting diodes arranged in a row and acting as

  light sources, to which one or more phosphors are assigned

  toreceptors respectively connected to a preamplifier. In this case

  rence, the infrared light clocked from the light diodes as well as the light reflected by the controlled object can be directed through at least one optical lens which is moved on the surface

of the controlled object.

  Suitably, a filtering stage may precede the signal amplifier of the signal analysis circuit and, as the fault signaling stage of the signal analysis circuit, it

  can advantageously be provided a monostable rocker which is curm-

  triggered by the pulse output signal from the trip stage

  and which delivers a fault pulse signal in the absence

  an output pulse from the trigger stage.

  Advantageously, the stage or stages of analysis of signaling

  The reading of faults in the textile checking device can be a machine cut-off system and / or a marking device connected to the checking head. The latter makes it possible to mark the defects noted. Advantageously, the signal analysis circuit, which includes, in a suitable and known manner, a fault counter, at least one optical signaling system and a keyboard for entering values and / or for actuating the microprocessor, can

  also be provided with a delay stage which can be triggered

  ché by the output signal of the fault signaling stage output to temporarily interrupt the operation of this

  latest. When checking knitted casings leaving circulating looms

  the latter, it is advantageous to prevent a

  fault already noted is not recorded again by the head

  trôle during subsequent rotations of the trade. In the case of the me-

  circular knitting thirds, on which generally appears, in the knitted hose, a defective longitudinal strip which is

  caused by switching operations in the control of the

  machine ganes and which should not be registered by the device

  control circuit, this or another interrupt circuit may,

-4 - 2588960

  appropriately, be triggered by a signal transmitter, by

  example by an inductive sensor, which scans the area of the long strip

gitudinal.

  The textile inspection apparatus in accordance with the invention

  tion can be realized in the form of a compact device whose

  control head can be easily adapted to specific uses

  specific, this control device being appropriately mounted

  required, on machines intended for manufacturing textile fabrics

  trôl and allowing to suppress any additional manual checking which, until now, usually had to be done on the finished textile yarn. The control device is easy to use because, thanks to the automatic sensitivity adjustment of the device, the adjustment operations are limited to key actuations the number of which can be determined in advance, which require no

  professional skills and which are for example intended for pre-employment

  ter a theoretical number of faults until the machine may not

  be stopped, or to preassign the number of degrees of deviation that the ni-

  trigger calf must adopt relative to the level of amplification-

  tion set, to consider as defects, for example, only

  the holes having a determined dimension.

  Other characteristics and advantages of an embodiment

  tion of a textile inspection device in accordance with the invention

  tion, intended to be used on a circular knitting machine, se-

  will now be detailed in the description which follows, made to

  by way of nonlimiting example, with reference to the appended drawings which represent: - FIG. 1, a schematic overview of a circular knitting machine equipped with the control device;

  - Fig. 2, a sectional view of a first embodiment

  tion of the optoelectric control head of the control apparatus, connected to a marking device; - Fig. 3, a front view of the control head according to the

arrow III of FIG. 2; -

  - Fig. 4, a schematic sectional view, corresponding to FIG. 2, of a second embodiment of the control head; - 5 -

  - Fig. 5, a block diagram of the electrical circuit of ana-

  lysis of signals from the recording equipment; - Fig. 6, a block diagram of the signal amplifier and of the triggering stage of the signal analysis circuit of the recording equipment; - Figs. 7 and 8, two signal diagrams illustrating the operating mode of the signal amplifier and of the trigger stage of the signal analysis circuit;

  - Fig. 9, a signal diagram illustrating the signaling

  tion of faults; and - Fig. 10, a schematic view of the signaling side and

  control of the housing of the recording equipment, which contains the circuit

cooked signal analysis.

  Fig. 1 shows the frame 10 of a circular knitting loom

  cular, comprising a drive block 11 located in the lateral position

  rale and intended for a needle cylinder not shown which rotates inside a turret 12, if necessary with a ribbed disc

  provided with needles, and which forms a knitted hose 13 in a known manner.

  From the moment he leaves the training area. stitches and the

  moment it reaches a rotating output and winding device

  Lement 14 of the circular knitting loom, the knitted hose 13 is

  controlled by a textile checking device used to detect

  ter knitting defects. The recording equipment is equipped with a

  optoelectric control head 15 which is applied against the exterior

  laugh of the knitted hose 13 and in front of which the knitted hose scrolls

  in rotation 13. The control head 15 is connected to an analysis circuit.

  signal lysis which, here, is incorporated into the meter's drive unit

  circular knitting tier, of which only the signaling and

command 16 is visible in FIG. 1.

  Figs. 2 and 3 show a first embodiment of the optoelectric control head 15. Its oblong housing 17, which

  is positioned in the longitudinal direction of the knitted hose 13, is re-

  linked to the frame 10 of the circular knitting loom by means of

  arms 18 and 19 and its feeler side is kept applied against the bo-

  knitted yau 13 by means of a tension spring 20. On the pal side

- 6b - 2588960

  fear, the shoemaker 17 is closed by a tip 21 into which is inserted

  There is a lens 22. Inside the housing 17 of the control head 15, a row of infrared light-emitting diodes 23, which are mounted at regular intervals in the longitudinal direction of the housing 17 and of the knitted hose 13, is arranged on one side of a partition wall 24 extending from the lens 22. On the other side of the partition wall 24 is a corresponding row of photodiodes 25 which pick up the quantity, reflected by the hose

  knitted 13 in lens 22, infrared light emitted in a manner

  re clocked by each of the corresponding light-emitting diodes 23 and directed through the lens 22 onto the surface of the knitted hose 13, and which transform it in known manner into an electrical signal which is transmitted to the analysis circuit of the control apparatus. Fig.

  3, which represents the feeler side of the control head, shows how

  the light diodes 23 and the corresponding photodiodes 25 are arranged in the form of a row and at regular intervals,

  behind the nozzle 21 provided with the lens 22.

  On the case 17 of the control head 15 is fixed a device

  positive marking 26 which, on its front face directed towards the hose

  knitted 13, has one or more marking points 27 which can

  wind be brought electromagnetically against the knitted hose 13 to identify a defect in the knitted hose recorded by the signal analysis circuit. The corresponding circuit elements of the

  control head, for example preamplifiers connected to photo-

  diodes, cadence generators and power supplies, are

  mounted on a printed board 29 located in the case 17.

  Fig. 4 shows a variant of an op-

  toelectric 15 in which, behind a transparent front plate

  annuity 21a of the shoemaker 17a, which is kept applied against the knitted hose 13, glass light guides 28 are arranged in front of the row of infrared light diodes 23a. Photodiodes 25a are located next to the front end of these glass light guides 28. All these components are mounted directly on the card

printed 29a.

  Fig. 5 represents a block diagram of the analysis circuit

- 7- 2588960

  of signals from the recording equipment. In the circuit, the routes of

  signal transmission are represented by single dashes

  chés or by double lines with triangular arrows. The figure re-

  has a power supply 30, which is connected to a battery (not shown) to protect the memory in the event of a breakdown, a microprocessor

  sor 31 associated with corresponding control circuits, and a

  control head port 32 which is connected to a series connection

  placed with a filtering stage 33, with a signal amplifier 34,

  a trip stage 35 and a trip signaling stage

  faults 36. Among several possible stages of signaling analysis

  faults, a machine cut-out stage 37 is shown

  you. The signal lines shown are a line 38 leading from the control head connection 81e 32 to the filtering stage 3, a line

  leading from another control head 39 connection to the microprocessor

  arrester 31, a line 42 leading from a sensor connection 41 (for example, an inductive sensor) to the microprocessor, a line 43 leading from the fault signaling stage 36 to a control circuit and

  signaling of microprocessor 31, a line 44 leading from a circuit

  microprocessor control circuit 31 at the shutdown stage

  machine 37, a line 45 leading from a micro-

  processor 31 to the marking device 26 shown in FIG. 2, and

  a line 47 leading from a key switch 46 to the microprocessor 31.

  Microprocessor control buses 48 and 49 connect the microprocessor

  stopper 31 to signal amplifier 34 and to trigger stage

  35. In addition, microprocessor control buses are shown.

  stopper 50 and 51 which are connected to a keyboard 52 and to a block of si-

optical generalization 53.

  In known manner, the signal analysis circuit comprises a fault counter not shown in detail, which is triggered by the output signals from the fault signaling stage 36, and whose counting position is displayed at the level of the block of

  optical signaling using a display device 58 shown

  felt in FIG. 1. The fault counter can be designed under the

  form of a comparison stage which is connected to a value indicator

  their setpoint in which a determined minimum number of faults,

- 8 - 2588960

  viewed on the display device 58, is entered from the keyboard 52, in the case where the machine must only be switched off when a determined minimum number of faults is reached. The figure also does not show a timing stage which is integrated into the microprocessor 3 control circuit! and which temporarily deactivates the fault signaling stage 36 when a fault signal appears on the latter,

  to prevent the same fault from being recorded twice.

  The off-state can, for example, be indicated by the flashing

  green light, while a light

  red lights indicate that the machine is switched off.

  Fig. 6 schematically shows the arrangement of the signal amplifier 34 and the trigger stage 35 of the signal analysis circuit. The signal amplifier 34 has a switching stage 54 which is controlled by the microprocessor and

  which allows you to vary the amplification gain of the am-

  actual planning 55 according to, for example, sixteen levels of am-

  total planning. Similarly, the trigger stage 35 is provided with a switching stage 56 which is controlled by the microprocessor

  and which adjusts the trigger level of the fault circuit

  actual triggering 57 according to, for example, sixteen different values

  férentes. Fig. 10 represents the signaling and control side 16

  of the shoemaker containing the signal analysis circuit provided with the elements

  circuit elements illustrated in Fig. 5. It features the device

  display 58, the keypad 52, the keyhole

  key switch 46, two indicator lights 59 and 60, an on-off switch 61, a mains connection cable 62 and three

  flange sockets 63, 64 and 65 intended to connect the control head

  the, the sensor (for example, the inductive sensor) and the

machine shutdown.

  The operating mode of the textile checking device is as follows: The checking head 15 applied against the textile strip to be checked, in this case against the knitted hose 13, delivers via

_- * 3 2588960

  of its photodiodes 25 signals corresponding to infrared light

  red reflexed and clocked received by the photodiodes. After having

  been preamplified and grouped in the control head 15, the

  signals of the different photodiodes 25 are transmitted, via

  diary of the connection 32, to the signal analysis circuit and, from there, to the filtering stage 33 via the signal line 38. Via the connection 39 and the signal line , the microprocessor 31 can know if a control head is connected. The spurious signals and the noise signals are filtered in the filtering stage 33. In the signal amplifier 34 provided

  downstream, an amplification is carried out according to an amplification gain

  one previously defined during a calibration procedure, which will be described later, and the signal thus amplified is

  transmitted to trigger stage 35, the trigger level of which

  This was also previously defined during the assessment procedure.

  lonnage described below. The diagram in FIG. 9 represents the ni-

  trigger calf 66 set at the time of calibration, as well as the signal curve 67 produced by the peaks of the different timing signals amplified in the signal amplifier 34. When

  the knit is free from defects, all timing signals am-

  are higher than the trigger level 66. If the knitted hose has holes, the amount of reflected light is very little or zero, so that the signal that appears at the

  fault and which is amplified uniformly in the si amplifier

  gnaux 34 is so weak that it is lower than the trigger level 66. FIG. 9 shows the shape of the signal curve on a first

  fault 68 caused by a small hole and on a second fault 69 pro-

  voided by a larger hole. Only a timing signal exceeding trigger level 66 generates an output signal at

the trigger stage 35.

  The fault signaling stage 36 is a so-called monostable flip-flop, the time constant of which is slightly greater than the synchronization interval existing between the signals supplied

  by the control head 15. The monostable rocker of the stage of si-

  generalization of faults 36 is therefore maintained at signal level 70, 10o-2588960

  shown in Fig. 9, as long as there are output signals

  appear, at the scanning rate, at the exit of the

  latch 35 located upstream. However, if an output signal from the trigger stage 35 is missing, which is the case with faults 68 and 69, the signal level 70 is interrupted for

  a short time 71 or for a longer time 72.

  These interruptions bring the fault signaling stage 36 to

  produce output signals which are transmitted through the line

  general 43 to microprocessor control circuits 31 to be

analyzes.

  As part of a calibration procedure prior to the

  error detection, the amplification gain of the signal amplifier

  gnaux 34 and the trigger level 66 of the succeeding trigger stage are adjusted according to the nature of the knitted hose 13 to be checked. To this end, the scanning signals supplied by the

  control head 15 during at least one complete rotation of the mete

  circular knitting tier from a faultless knitting area

  are first analyzed by the microprocessor 31 and the amplification gain

  cation of signal amplifier 34 is suitable for the weakest signal, i.e. the signal provided by the point of the free knit

  fault with the smallest degree of reflection. The gain in

  signal amplifier is set to one of

  its sixteen levels, so as to also obtain a good amplifi-

  cation of the weakest scanning signal. In the case of textiles

  signal levels can differ dramatically

  bearing. On the other hand, there are practically no differences

  In the case of plain textiles with a simple structure. In this case

  microprocessor 31 also ensures that the level of am-

  planning respects a sufficient deviation from power

  upper limit of the signal amplifier 34.

  The diagrams in Figs. 7 and 8 illustrate, in the part

  left, the processes that take place in the si- amplifier

  34 during the calibration procedure. In the embodiment

  tion according to FIG. 7, the amplification gain is increased in stages according to the amplitude of the clocked scanning signals - il 2588960

  received, which gives the staircase curve 73. In this case, if this-

  the staircase curve exceeds the maximum level 66max, indicated on the diagram, of the triggering stage 35 provided downstream, as is the case in the portion of curve 73a-, the microprocessor 31 reduces the amplification gain to an amplification level whose amplitude is less than the maximum level 66max of the triggering stage, so that the curve 73 adopts the shape of the portion 73b of FIG. 7. The regular shape of the curve in portion 73b indicates

  that the controlled knitted hose is united.

  In the embodiment of FIG. 8, the amplification gain

  cation of the signal amplifier 34 passes, at first,

  an amplification range 73a, which is greater than the level of de-

  maximum triggering 66max, at an amplification range therein

  lower and which corresponds to the portion of curve 73b.

  At the end of this adjustment of the amplification gain of the amplifier

* signal processor 34, microprocessor 31 lowers the level of -

  trigger 66 of trigger stage 35 in steps, compared to

  port at maximum level, as indicated on the right side of the

  grams of Figs. 7 and 8. The trigger level 66 is lowered at least to the bearing 66a which is shown in Figs. 7 and 8 and which is clearly below the portion of curve 73b of the signal amplifier 34. If it is desired that only the grossest faults are signaled, the trigger level 66 is further lowered until bearing 66b or 66c, this adjustment can be carried out by the operator from the keyboard 52 of the front plate

16 of the signal analysis circuit.

  It is only at the end of the described calibration procedure that the fault signaling stage 36 is operational and that the actual fault control operation begins, the

  result has been described with reference to the diagram in FIG. 9.

- 12 - 2588960

Claims (10)

  1. Textile control device for recording   trer faults, including at least an optoelectronic control head   stick, which works on the principle of light reflection and   which serves as a signal transmitter, and an electrical circuit   signal lysis which includes a microprocessor and which provides   output signals for controlling at least one communication device   mutation, characterized in that the control head (15) comprises at least one light source (23, 23a), which delivers in known manner   light pulses at a predetermined rate, and a re-   corresponding optoelectric light sensor (25, 25a), which detects the reflected light signals delivered in a timed manner, and in this   that the signal analysis circuit connected to at least one receiver lu-   miner (25, 25a) comprises a signal amplifier (34), which is controlled by the microprocessor (31) and which has several ranges of gain of amplification, a stage of release (35), which is controlled by the microprocessor ( 31) and which has a trigger level (66) adjustable as a function of the amplification gain of the signal amplifier (34), a fault signaling stage (36) and at   at least one fault signaling analysis stage (37), these differences   rents elements being mounted one behind the other.   2. Apparatus for checking textile fabrics according to the resale   dication 1, characterized in that the optoelectric control head   (15) comprises several infrared light-emitting diodes (23, 23a) available   placed in a row and acting as light sources, to which   several photoreceptors (25, 25a) are assigned respectively linked to a preamplifier.   3. Apparatus for checking textile fabrics in accordance with the resale   dications 1 and 2, characterized in that the infrared light caden-   The light diodes (23, 23a) as well as the light reflected by the controlled object (knitted hose 13) are directed through at least one lens (22) or an optical guide (28) which is moved by   relation to the surface of the object checked. - 13 -   4. Apparatus for controlling textile fabrics in accordance with one   any one of claims I to 3, characterized in that a stage of   filtering (33) precedes the signal amplifier (34) of the a- circuit signal analysis.   5. Apparatus for controlling textile fabrics in accordance with one   any one of claims I to 4, characterized in that the stage of   fault signaling (36) of the signal analysis circuit is a   monostable rocker which is controlled by the pulse output signal   the trigger stage (35) and which delivers an   fault pulse in the absence of a stage output pulse trigger.   6. Apparatus for controlling textile fabrics in accordance with one   any one of claims 1 to 5, characterized in that the stage   of fault signaling analysis is constituted by a machine cut-off system (37) and by a marking device   (26) which is connected to the control head (15).   7. Apparatus for controlling textile fabrics in accordance with one   any one of claims I to 6, characterized in that the circuit   signal analysis comprises, in known manner, a failure counter   faults, at least one optical signaling system (58) and one   use (52) to save values and / or to activate the micro- processor (31).   8. Apparatus for controlling textile fabrics in accordance with one   any one of claims 1 to 7, characterized in that the circuit   signal analysis includes a delay stage which can be   triggered by the signal signal from the signal stage output   fault (36) to temporarily interrupt operation   ment of said fault signaling stage (36).   9. Apparatus for controlling textile fabrics in accordance with one   any of claims 1 to 8, characterized in that the comp-   fault analyzer of the signal analysis circuit is designed under the   form of a comparison stage which is connected to a value indicator their set point.   10. Method for automatically calibrating a device   Textile control board in accordance with any of the - 14 - 2588960   Vendications 1 to 9, characterized in that the signal amplifier (34) is first adjusted, by the microprocessor (31), to the amplification range necessary to detect the reflection signal the   weaker occurring during a predetermined calibration time   born or from a predetermined relative movement path of the control head (15) on a portion of the textile fabric free from defects, and in that the trigger level (66) of the trigger stage (35) is then shifted, via the microprocessor (31), according to a preselected deviation (66a, 66b, 66c) below the level of   adjusted sensitivity (curve portion 73b) of the signal amplifier   signals (34), before the microprocessor (31) returns the stage of si-   generalization of operational faults (36).