US3530690A - Yarn inspection apparatus - Google Patents

Yarn inspection apparatus Download PDF

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Publication number
US3530690A
US3530690A US717076A US3530690DA US3530690A US 3530690 A US3530690 A US 3530690A US 717076 A US717076 A US 717076A US 3530690D A US3530690D A US 3530690DA US 3530690 A US3530690 A US 3530690A
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Prior art keywords
yarn
detector
light
broken
sheet
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US717076A
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Lawrence Creigh Nickell
Raymond Baines Fertig
Henry T Sessions
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Appalachian Electronic Instruments Inc
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Appalachian Electronic Instruments Inc
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    • D—TEXTILES; PAPER
    • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
    • D04B—KNITTING
    • D04B35/00—Details of, or auxiliary devices incorporated in, knitting machines, not otherwise provided for
    • D04B35/10—Indicating, warning, or safety devices, e.g. stop motions
    • D04B35/14—Indicating, warning, or safety devices, e.g. stop motions responsive to thread breakage
    • D—TEXTILES; PAPER
    • D03—WEAVING
    • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
    • D03D51/00—Driving, starting, or stopping arrangements; Automatic stop motions
    • D03D51/18—Automatic stop motions
    • D03D51/20—Warp stop motions
    • D03D51/28—Warp stop motions electrical

Definitions

  • the present invention relates to yarn inspection apparatus for continuously monitoring a large group of yarns arranged to move substantially in unison in side-by-side relation in the form of a warp or warps in one or more feed planes, the groups of yarns in each plane being hereinafter referred to as a yarn sheet, and detecting occurrence of any broken yarn ends in the yarn sheet for producing a defect signal.
  • Feeding of yarns in large groups as yarn sheets occurs in many different types of yarn handling apparatus, such as knitting machines, particularly of the tricot or warp knitting machine type, in weaving machines, in feeding of yarns from a warping machine to the beam or beams of knitting machines, and similar yarn making and textile manufacturing installations.
  • knitting machines particularly of the tricot or warp knitting machine type
  • weaving machines in feeding of yarns from a warping machine to the beam or beams of knitting machines, and similar yarn making and textile manufacturing installations.
  • An object of the present invention is the provision of novel yarn inspection apparatus for monitoring yarn sheets by providing a light beam spanning the width of the yarn sheet immediately adjacent but spaced out of the plane thereof and producing a defect signal upon passage of a broken yarn and through the light beam, which achieves reliable monitoring of fine yarn in yarn sheets of large width, which minimizes vibration and alignment problems, and which is more readily adaptable to be fitted into the limited spaces available in yarn handling machines.
  • Another object of the present invention is the provision of a novel broken yarn detection apparatus for moni toring yarn sheets of large width, wherein a monitoring light beam spans the width of the yarn sheet and is spaced slightly out of the plane thereof, and wherein the light for said light beam is projected from a detector head adjacent one edge of the yarn sheet and is returned to the detector head by a retro-reflective target located adjacent the other edge of the yarn sheet, or at a selected intermediate point between the edges thereof, to reduce alignment and vibration problems, increase sensitivity of the system, and facilitate detection of very fine yarns.
  • Another object of the present invention is the provision of novel detector head structure for a broken end detector as described in the immediately preceding paragraph.
  • Another object of the present invention is the provision of novel broken yarn end detector apparatus for monitoring a yarn sheet, wherein a light beam spans the width of the yarn sheet at a location spaced slightly out of the plane thereof adjacent one side of the yarn sheet, and pressurized air tube means span the width of the yarn sheet adjacent the opposite side thereof for blowing broken yarn ends into or through the light beam, wherein reduced power is required for a motorized blower supplying air to the tube to achieve effective air distribu tion in useful directions therefrom.
  • FIG. 1 is a fragmentary, somewhat diagrammatic perspective view, illustrating a typical installation of a broken yarn detecting apparatus of the present invention in conjunction with a two-bar, double width tricot knitting machine;
  • FIG. 2 is a somewhat diagrammatic, fragmentary, vertical section view illustrating a typical installation of the broken yarn detecting apparatus of the present invention incorporated in a three-bar tricot knitting machine;
  • FIG. 3 is a fragmentary perspective view illustrating a typical installation of the broken yarn detecting apparatus of the present invention, associated with a yarn sheet in the feed path between a creel of a warper and a beam and extending in a generally horizontal plane;
  • FIG. 4 is a rear elevation view of the detector hea employed in the broken yarn detecting apparatus of the present invention.
  • FIG'. 5 is a vertical longitudinal section view through the detector head, taken along the line 55 of FIG. 4;
  • FIG. 6 is an elevation view of the light mask associated with the lens barrel mount of the detector head, as viewed along the line 6-6 of FIG. 5;
  • FIG. 7 is a diagrammatic view of a typical air supply system for supplying pressurized air from a blower to the air discharge tubes of the broken yarn detector apparatus for a double width tricot knitting machine installation;
  • FIG. 8 is an exploded perspective view of the target structure employed with the broken yarn detector apparatus
  • FIG. 9 is a schematic diagram of the preamplifier employed in the detector head.
  • FIG. 10 is a schematic diagram of a relay driver amplifier circuit which may be used with the broken yarn detector apparatus of the present invention.
  • FIG. 11 is a schematic diagram illustrating additional circuitry which may be associated with the relay driver amplifier circuit portions of FIG. 10, having plural input channels respectively associated with different yarn sheets in a tricot knitting machine installation to facilitate identification of the yarn sheet in which a broken end occurs;
  • FIG. 12 is a schematic diagram of a reset timing circuit usable with the broken yarn detecting apparatus of the present invention when the same is associated with a knitting machine to permit the operator to control the detecting apparatus automatically from the controls on the knitting machine, and
  • FIG. 13 is a schematic diagram of a regulated power supply which may be used with the present invention.
  • FIG. 1 diagrammatically illustrating the broken yarn detecting apparatus of the present invention in a double-width tricot knitting machine installation, there is shown the usual top warp beam 16 and bottom warp beam 17 of a conventional tricot knitting machine from which the yarns are fed under tension in yarn sheets 18 and 19 through the conventional reeds, indicated schematically at 20a and 20b, and tension bars 21a and 21b, to the needle position 22, where the yarns are knitted to form the knitted cloth product 23.
  • a double width machine providing a yarn sheet of approximately 168 inches or more width, although it will be appreciated that the installation will be similar for single width knitting machines having the usual yarn sheet width of about 84 inches.
  • a pair of air discharge tubes 24, 24a Disposed in the zone between the tension bars 21:: and 21b and the needle zone 22, and to the rear of the rearmost yarn sheet 19 fed from the lower beam 17, as viewed in FIG. 1, are a pair of air discharge tubes 24, 24a disposed in axial alignment so as to substantially span the width of the yarn sheets, each of the air tubes having an elongated air discharge slit 25, 25a extending substantially the length thereof and facing generally toward the yarn sheets.
  • the two air discharge tubes 24, 24a are supplied with pressurized air through suitable tubing, generally indicated at 26, from a conventional motor driven blower 27. If only a single width knitting machine is to be monitored, only a single air discharge tube 24 need be provided.
  • one or more detector beam assemblies are arranged to detect any broken yarn ends propelled from the planes of the yarn sheets 18, 19 in the direction of the detector beam assemblies by the air discharged from the tube or tubes 24, 24a. While certain installations need only one of such detector beam assemblies, as will be described later, three of such assemblies are illustrated in FIG. 1, designated respectively 28a, 28b and 28c. Each of the assemblies 28a, 28b and 280 are identical in construction and detailed description of one will suffice for each.
  • the assembly 28a comprises a detector head 29 shock mounted outwardly of one edge, the proximal edge as viewed in FIG.
  • a high intensity light beam 30 of narrow cross section along a rectilinear axis so as to span the width of the yarn sheet 18 and be spaced slightly from the plane of the yarn sheet 18 to the side thereof opposite the side on which the tubes 24, 24a are located.
  • a rigidly mounted target assembly 31 Adjacent, and spaced slightly outwardly from, the opposite edge of the yarn sheet 18 is a rigidly mounted target assembly 31, formed of retro-reflective material, such for example as retrorefiective tape manufactured under the trade name, Scotchlite, by Minnesota Mining and Manufacturing Company, having the property of returning light along the same path as the incident light rays, regardless of the angle of incidence.
  • the retroreflective target assembly 31 returns the light rays projected thereto from the detector head 29 back along the same light beam axis to the detector head 29, where the returning light rays are directed to a phototransistor, as hereinafter described, which responds to the intensity of light returned thereto.
  • the components of the second and third detector beam assemblies 28b and 280 are identical to those of the assembly 28a and the components thereof are therefore indicated by the same reference characters used for the components of the assembly 28a.
  • Signals derived from the phototransistors of the detector heads 29 are preamplified in the detector heads, and coupled to a relay driver amplifier unit 32 to activate the relay of a relay unit 33, and visual and/or audible alarms, if desired, to signal detection of a broken yarn end upon passage of a broken yarn end through either of the beams 30 and variation of the phototransistor current in response thereto.
  • FIG. 2 illustrating a three-bar tricot knitting machine, which correspond to components of FIG. 1, are indicated by like reference characters, and a third or intermediate warp beam 17 is also illustrated, from which the yarns forming the middle yarn sheet 19 are drawn through a reed 20c and over a tension bar 21c and fed to the needle zone 22.
  • FIG. 2 It will be apparent from an inspection of FIG. 2 that, since the yarn sheets, whether there be two or three yarn sheets, are in almost vertical planes near the needles 22 and the air discharge tube 24 and detector beam 30 are adjacent the yarn sheets in this region, it is much easier to blow out a broken end from the plane of the yarn sheet through the detector beam 30.
  • the broken end will swing out with very little air blowing on it, and in fact, since it is usually tilted downwardly and rearwardly from the tension bar 21a, the broken end from the front yarn sheet 18 will usually fall out without air.
  • a blower of quite low horsepower is adequate to insure blowing of broken ends into the light beam.
  • FIGS. 1 While detector beam assemblies for each of the front yarn sheet and rear yarn sheet are illustrated in FIGS. 1
  • FIG. 3 An alternative installation for applications such as monitoring the yarn sheet being transported from a warping machine to the beam of a knitting machine is illustrated in FIG. 3, wherein the yarn sheet is indicated by the reference character 18.
  • the detector beam assembly 28a like that of the FIG. 1 and FIG. 2 installations, comprises a like detector head 29 directing a monitoring light beam 30 to the retro-reflective target 31 for return along the incident ray path to the detector head 29.
  • the monitoring light beam 30 in this installation is spaced slightly above the plane of the yarn sheet 18' and an air discharge tube 24 similar to the correspondingly numbered air discharge tube of the FIG. 1 embodiment is spaced slightly below the yarn sheet plane and is supplied with pressurized air through tubing 26 from motorized blower 27.
  • the detector head 29 of the preferred embodiment herein illustrated comprises an outer casing 35 of generally box shape configuration having an apertured front end wall 35 which is provided with an opening 35a forming an optical aperture.
  • a mounting block 36 is disposed within the casing and carried by the front end wall 35', to rigidly support in proper alignment the lamp 37, phototransistor 38, semi-transparent mirror 39 and a plano-concave lens 40.
  • the lamp 37 for example, may be a General Electric Type 1876 having a short, fine filament and rather high light output, which draws about two amperes at 2.5 volts DC.
  • This lamp is supported in appropriate bore in a portion of the mounting block 36, being retained therein, for example, by the set screw 36', to dispose the filament in alignment with a small aperture 41 at the rearmost end of the internal bore 41 in which the semi-transparent mirror 39 is mounted and with which the phototransistor 38 communicates through the bore extension 41a.
  • the preamplifier circuit 42 mounted within the casing 35 is the preamplifier circuit 42 provided on a suitable printed circuit board or the like and fixed to the mounting block 36.
  • a lens tube mounting block 43 Projecting externally from the front end wall 35 in concentric relation with the projected axis of the opening 35a is a lens tube mounting block 43 having an internally threaded aperture therein and a lens tube 44 having a constricted external threaded portion threaded into the bore of the mounting block 43 and carrying a plano convex lens 45 adjacent the outer end thereof.
  • the planoconcave lens 40 has a 2-inch focal length and the planoconvex lens 45 has a 4-inch focal length.
  • the purpose of the small hole 41 in the mounting block 36 is to prevent light leakage caused by spurious reflections from reaching the phototransistor 38.
  • This hole 41 and the filament of the lamp 37 are slightly displaced downwardly from the center axis of the two lenses 40, 45 to correct for the refraction occurring in the semi-transparent mirror 39.
  • the light from the filament of the lamp 37 which passes through the small hole 41 is transmitted through the semi-transparent mirror 39 and is caused to diverge by the plano-concave lens 40.
  • the virtual image of the filament produced by this lens 40 is about half the size of the filament, making it possible to project a narrow light beam over long distances.
  • the divergent light from the plano-concave lens 40 then passes through the planoconvex lens 45, which is adjusted to a position to substantially collimate the light or produce a sharply focused image of the filament on the target 31.
  • the reflected light from the target 31 travels back through the two lenses 45, 40 to the semi-transparent mirror 39, where it is reflected through a substantially angle into the bore extension 41a to the photo sensitive surface of the phototransistor 38.
  • the above arrangement provides a monitoring light beam of very narrow cross section appropriate for detection of opaque objects having an area equal to as little as about one percent of the light beam, so as to span a yarn sheet width of at least about 180 inches and permit detection of small yarns, for example, about 15 denier yarn, which has a diameter of about .003 inch.
  • a three inch focal length plano-convex lens 45 may be used and adjusted for a slightly out-of-focus image, in the direction of collimation, on the target 31, having about the same area as the face of the plano-convex lens 45, which in practice may be about one inch in diameter.
  • This focusing method produces a light beam which is more uniformly sensitive than would result from sharpl focusing the image of the filament on the target 31, as a sharply focused image of the filament would make the light beam more sensitive away from the detector head, due to the smaller cross sectional area of the beam.
  • a rectangular mask can be placed between the lens tube mounting block 43 and the exterior face of the front end wall 35, with its center in registry with the center axis of the opening 35a, to cause a light beam of rectangular cross section to be projected.
  • This provides a larger signal than a circular cross section light beam in certain cases and is especially helpful where there is only a limited movement of the piece of broken yarn which may not drop through the light beam, but only becomes slack and barely enters the light beam.
  • the four inch focal length piano-convex lens 45 is used, and is adjusted to produce a light pattern at the target 31 having an area of about the same size as the face of the lens 45, which is about one inch in diameter, with the image of the filament sharply focused and slightly larger in area than the face of the lens 45.
  • this beam, producing the sharply focused image is not absolutely uniformly sensitive along its length, satisfactory results are obtainable.
  • plano-convex lens 45 may be changed to a five inch focal length lens, which requires a larger detector head, or the four inch focal length lens 45 can be retained and the lano-concave lens 40 changed to a one inch focal length lens. Either of these alternative solutions, however, result in slightly less light being projected, with decreases in the sensitivity of the system.
  • the mask 46 does not move as it would if it were attached to the outer portion of the lens tube 44 in the vicinity of the lens 45, and thus the lens tube 44 can be freely adjusted through any small angle desired to achieve proper focusing or defocusing of the image. If the mask 46 were carried on the lens tube 44, the lens tube would have to be turned in 180 increments in order to maintain the mask properly positioned in relation to the projected image of the lamp filament, and such increments would not always produce optimum focusing conditions.
  • plano-concave lens 40 2-inch focal length is mounted so that the fiat surface faces the semi-transparent mirror 39 and lamp 37.
  • the lens 40 By arranging the lens 40 in this manner, light reflections from the curved surface of the lens are decreased. If the 2-inch focal length plano-concave lens 40 were arranged with the concave surface facing the semi-transparent mirror 39, it was found that this curved surface was apparently acting as a concave mirror to some extent, causing substantial light reflections to be returned to the phototransistor 38, causing a higher background current.
  • the lens 40 By reversing the arrangement of the lens 40, the normally occurring reflections from the lamp to the phototransistor were greatly reduced so that practically all of the phototransistor current is a result of the light reflected back from the target 31, permitting a higher value of load resistor to be used before saturation occurs and increasing the sensitivity of the detector head. If the focal length of the lens 40 differs substantially from the light path distance between lens 40 and the phototransistor 38, it is sometimes advantageous to reverse the disposition of lens 40, disposing its flat surface towards the mirror 39.
  • the detector head casing 35 has a pair of axially aligned trunnions 47 projecting from the opposite sides thereof and received in apertures of corresponding cross section in a pair of upwardly projecting arms 48a of a mounting yoke 48.
  • Set screws 48a are provided in the yoke arms to lock the trunnions 47 against rotation about the axes of the trunnions.
  • the base 48b of the yoke 48 is centrally apertured to receive a cylindrical post 4911 rising from a rubber shock mount assembly 49.
  • the shock mount assembly 49 comprises a rigid top plate 49b and a rigid bottom plate 490, assembled together in spaced relation by bolts 49d at the four corners thereof extending through four, corner located, rubber shock mounts 49d.
  • Set screws 48b in the yoke base 48b are provided to lock the yoke against rotation about the post 49a.
  • the shock mounts are provided to protect the filament of the lamp 37 from excessive vibration. While vibration is not nearly as critical in this apparatus as it would be with a photoelectric system having separate transmitters and receivers, because the light beam can move around to some degree on the retro-reflective target 31 Without serious effect, the provision of the shock mounts reduces movement of the lamp and thus movement of the light beam on the lens system to minimize noise problems which might otherwise Occur from such vibrations.
  • the target assembly 31 is of simple construction and comprises a rigid, substantially rectangular backing plate 51 having a rectangular sheet of retro-reflective tape or similar retro-reflective material 52 on the face thereof.
  • the retro-reflective tape 52 is covered with a thin glass plate 53, sealed with a gasket 54 and assembled to the backing plate 51 with a frame 55, to prevent dirt, lint, grease and other foreign matter from collecting on the retro-reflective tape 52. All of such contaminants cut down on the intensity of the light reflected back from the target and thus decrease the sensitivity of the system. Grease is particularly detrimental and hard to remove from the exposed surface of retro-reflective tape.
  • the target assembly 31 is fixed at a small angle a few degrees in either the vertical or horizontal plane to the axis of the detector head lenses 45, 40, so that these reflections from the glass plate which would otherwise occur are not directed back to the detector head.
  • the detector head can be simply aligned, by loosening the set screws 4812' on the bottom swivel joint defined by the post 490, after which the detector head is turned until the light beam strikes the approximate center of the target 31 in a horizontal plane, and the bottom set screws 48b are tightened.
  • the set screws 48a for the side swivel joint defined by the trunnions 47 are then loosened and the detector head turned about the axis of these trunnions until the light beam strikes the approximate center of the target in the vertical plane, after which the set screws 4841 are tightened.
  • pressurized air from the blower 27 is preferably delivered to the air discharge tube 24, and the air discharge tube 24a, if a double width machine installation is involved, by feeding the pressurized air to a pair of spaced locations substantially half way between the longitudinal centerof each tube and the end thereof.
  • This is accomplished by means of the hose sections 56a, 56b and 560, preferably formed of threeinch diameter hose, and a pair of two-inch hose sections 57a, 57b, leading from the three-inch hose sections to air inlets 57a, 57b at the tube 24, and like inlets at the tube 24a, if present, spaced for example 42 inches apart and located 21 inches from the adjacent end of a tube which is 84 inches long.
  • the air discharge tube 24 in this example has a diameter of about one and one-half inches.
  • blower 27 can be located to one side of the machine and supply air to one end of the manifold hose section 56b, 560, if it is more convenient to do so.
  • FIG. 9 shows the schematic circuit for the preamplifier 42 enclosed in the detector head 29.
  • the preamplifier includes an emitter follower stage, a Zener diode regulator and several filter circuits.
  • a regulated voltage of 28 V. DC. is used to supply power to the preamplifier 42.
  • Capacitor 42C2 is a tantalum unit which is used to bypass any noise signals, especially high frequency transients, coming in on the 28 V. DC. supply.
  • Resistor 42-R1 sets the current for the zener diode 42-CR1 to the correct value.
  • Zener diode 42CR1 sets the voltage for the phototransistors 42-Q1 and its load resistor 42-R2.
  • Capacitor 42-C1 limits the high frequency response of the phototransistor 42-Q1 to further suppress transients.
  • Resistor 42-R2 is the load resistor for the phototransistors 42- Q1. When light strikes the phototransistor 42-Q1, a certain amount of current flows through 42-Q1 and the load resistor 42-R2, depending on the light level. If the light level decreases due to an obstruction entering the light path, less current flows through 42-Q1 and 42-R2. This produces a negative pulse across 42R2. This pulse is applied to the base of transistor 42Q2, an emitter follower stage having a high input impedance. This causes less current to flow through 42Q2 and produces a negative pulse across resistor 42-R3 in the emitter of 42Q2.
  • This pulse will be slightly less in amplitude than the pulse applied to the base of 42-Q2 due to the emitter follower connection of 42-Q2.
  • Resistor 42-R4 and capacitor 42-C3 form a filter network to further attenuate any high frequency transients. Since the output impedance in 42-Q2 is very low, the output impedance of the preamplifier is on the order of 1000 ohms, due to 42R4 for signal frequencies, which is satisfactory for this application.
  • Resistor 42-R2 is also the calibrating resistor for the detector head. The 10K value shown is only a typical value. Its actual value depends on the light level and the gain of the phototransistor.
  • the relay driver amplifier 32 which responds to the signal output from the preamplifier 42 of the detector head, is a high gain, narrow bandwidth amplifier having an extended low frequency response and limited high frequency response. It consists of an integrated circuit operational amplifier directly coupled to a differential amplifier, followed by a silicon controlled switch which in turn operates the control relay of relay unit 33, and is schematically illustrated in FIG. 10.
  • the signal a negative pulse from the detector head, is connected to potentiometer 32-R1, the sensitivity control, by means of a shielded cable.
  • the negative pulse appearing on the slider of 32-R1 is coupled to the negative input of an 809CE operational amplifier 32-A by capacitor 32-C1 and resistor 32-R2.
  • the feedback resistor 32-R5 from the output to the input of the amplifier 32-A.
  • the feedback network consisting of 32-R5 and 32-R2, determines the voltage gain of the amplifier, in this case about 75.
  • a small capacitor 32C3 is connected across 32-R5 and serves to limit the high frequency response of the amplifier.
  • a voltage divider consisting of resistor 32-R3 and 32-R4 is connected across the 28 V. DC power supply. The junction of 32R3 and 32-R4 is connected to plus input of the amplifier 32-A and sets the DC. input and output levels of the amplifier.
  • the output signal of the amplifier 32-A a positive pulse, is direct coupled to the base of transistor 32Q1, which in turn appears across the emitter resistor 32R6.
  • the positive pulse across 32-R6 is coupled to the emitter of transistor 32-Q2 by resistor 32R7.
  • a positive pulse at the emitter of 32-Q2 causes a positive pulse to appear across resistor 32-R8 in the collector of 32-Q2.
  • Capacitor 32-C5 across 32-R8 serves to limit the high frequency response of this stage.
  • Resistors 32R9 and 32-R10 across the 28 V. DC. supply provide proper bias for the base of 32Q2.
  • the positive pulse appearing on the collector of 32-Q2 is coupled by capacitor 32-C6 to resistor 32-R11 and by resistor 32-R12 to the gate of the silicon controlled switch 32-Q3.
  • Resistor 32R12 and capacitor 32-C8 form a filter to eliminate high frequency noise signals from 32Q3.
  • Diode 32CR1 protects 32-Q3 from high negative pulses.
  • Resistor 32-R13 and 32-R14 across the 28 V. DC. supply comprise a voltage divider for supplying fixed bias to 32-Q3 which lessens temperature effects of 32Q3.
  • Relay REL which may be incorporated in relay unit .33, resistor 32-R15 and manual reset switch 32-SW1 are in the anode circuit of 32-Q3.
  • One set of contacts on REl is used to operate an indicator lamp 32-11, while the other set of contacts is available for external control or alarm purposes.
  • the diode 32-CR2 is used to suppress the inductive voltage pulse which ap- 1 1 pears across relay RE1 when 32SW1 opens.
  • Capacitor 32-C7 is a transient filter for 32Q3, while 32-C2 is a transient filter for the 28 v. D.C. supply.
  • 32-C2 is a tantalum unit which is superior for high frequency use.
  • the low frequency response of this amplifier is quite low and is determined by capacitor 32C1 and 32-C6.
  • the high frequency response is determined by capacitor 32-C3, 32-C5 and 32-C8 and is usually adequate. If faster response is needed for a particular application, it is only necessary to make these capacitors smaller.
  • This relay driver amplifier circuit is adequate for single yarn sheet applications, such as the type illustrated in FIG. 3, or one wherein the single monitoring beam is disposed slghtly below the plane along which the warped threads are fed.
  • a slightly modified relay driver amplifier circuit is desired wherein three separate amplifier channels lead from the three respective detector heads 29 and an indicator lamp is associated with each channel for respectively indicating the beam which detected a broken yarn end.
  • FIG. 11 Such a modification of the relay driver amplifier circuitry is illustrated in FIG. 11, with that portion to the left of the broken line 10', 10', corresponding to the schematic circuit illustrated to the left of the similarly numbered broken line in FIG. 10.
  • normally closed relay contacts 3E, SD of relay RES to be later described, and resistors 32-R16 and 32-R15 are connected between the manual reset switch SW1 and the silicon controlled switch 32-Q3.
  • resistors 32-R16 and 32-R15 are connected between the manual reset switch SW1 and the silicon controlled switch 32-Q3.
  • Across 32-I1 is a resistor 32-R15' which parallels the lamp and allows the rest of the circuitry to work even if the lamp burns out.
  • Each of the other two channels is identical to channel 1 and connects to the circuit of FIG. 11, as indicated.
  • Connected to the cathode of 32-Q3 in channel 1 and also in channels 2 and 3 are diodes 32CR2, 32-CR3 and 32- CR4 for isolating the three amplifiers from each other.
  • the current flowing through resistor 32-R13 causes the voltage on the anode of diode 32-CR2 to be sufiicient to pass additional current through resistor 32-R26 and the base of transistor 32-Q4 which causes it to conduct.
  • Resistors 32-R26 and 32-R27 form a voltage divider to prevent 32Q4 from conducting because of the fixed bias, about 1 volt, on the cathode of 32Q3 before it fires.
  • relay RE2 When 32-Q4 conducts, relay RE2 is energized through current limiting resistor 32-R17.
  • One set of contacts on 32-RE2 turns on indicator lamp 32-I2 and the other set applies 28 v. D.C. to the RC timing network composed of 32-C9 and 32-R19. This produces a positive pulse across resistor 32-R19 which is applied to the gate of field elfect transistor 32-Q5, a very high input impedance device. This causes it to conduct.
  • resistor 32-R21 Initially, it was cut off by the voltage divider composed of resistors 32-R23 and 32-R22 from the 28 v. D.C. supply to ground, applying fixed bias to the source of 32-Q5.
  • resistor 32-R21 When current flows through resistor 32-R21, a negative voltage is applied to the base of PNP transistor 32-Q6, which causes it to conduct and energize relay REl through current limiting resistor 32-R24.
  • One set of contacts on REl turns on indicator lamp 32-I3, while the other set energizes the stop relay RE7, the contacts of which are in the control circuit of the knitting machine and cause it to stop when the contacts open.
  • Resistor 32R19 and diode 32-CR6 are used to discharge 32-C9 through resistor 32-R18.
  • Resistor 32-R20 is current limiting resistor for 32-Q5.
  • the diode 32-CR7 across relay RE1 is used to suppress the inductive voltage from REI when 32-Q6 cuts off.
  • the R-C network of 32-R25 and 32-C10 across relay RE7 is another inductor spike suppressor.
  • the relay contacts RE3D and RESE in the anode circuit of 32-Q3 are automatic reset contacts for 32-Q3 which in turn resets relay RE2.
  • FIG. 12 shows a stop and reset timing circuit 60 to permit the operator to control the broken yarn detector automatically from the conventional controls on the knitting machine.
  • the holding coil on the machine automatically resets the detector system.
  • the reset timing circuit works as follows: When the operator closes the start switch on the knitting machine, relay RE6 is energized from the holding coil in the control circuit of the machine. This causes contact RE-6B and RE6C to close, charging 60C1 through 60-R3 from the 28 v. D.C. power supply. 60-R1, 60R2 and 60-CR1 form the discharge path for 60C1.
  • the positive voltage pulse formed across 60R3 is applied to the gate of '60-Q1 by current limiting resistor 60R4.
  • FIG. 13 shows a power supply circuit 61 which may be used with the three detector beam installation, whereby two highly regulated feedback type power supplies provide 28 v. D.C. for the relay driver amplifier 32 and preamplifier 42 and 2.5 v. D.C. for the detector head lamp 37.
  • the 2.5 v. D.C. regulator the 7.5 v. A.C. winding of power transformer 61-T1 is rectified by bridge rectifier 61-CR1 and filtered by capacitor 61-C1. This voltage is applied to the collectors of transistors 61-Q4, 61-Q5, 61-Q11, 61-Q12, 61-Q13 and 61-Q14.
  • 61-Q5, 61-Q12 and 61Q14 which are driven by the three driver transistors 61Q4, 61-Q11, 61-Q13, to provide an appropriate 2.5 v. D.C. supply to the three detector heads.
  • the voltage at the junction of emitter resistors 61-R25, 61-R27 and 61-R29 is applied to the base of transistor 61-Q3, which is one-half of a differential amplifier, through resistor 61-R10.
  • Across zener diode 61CR3 is a voltage divider composed of resistors 61R4, 61-R5 and 61-R6.
  • 61-R5 is the voltage adjust potentiometer.
  • the voltage on the slider of this potentiometer is the reference voltage. Any difference between the reference voltage and the output voltage is amplified by the differential amplifier composed of 61-Q2 and 61- Q3, which are matched transistors for low drift with temperature.
  • the output of 61-Q2 is connected to the base of transistor 61-Q1.
  • the collector of -61-Q1 is connected to the base of 61-Q4, 61Q11 and 61-Q13, which in turn drive the base of their companion power transistors. This completes the feedback loop, and because of the high loop gain used, insures good regulation.
  • the collector of 61-Q1 is connected to the base of 61- Q4, 61-Q11 and 61-Q13, which causes them to draw less current. Since the emitter current of the driver transistors is the base current of the power transistors, this causes the latter to pass less current and bring the output voltage of the regulator back to 2.5 V. DC.
  • Capacitor 61-C2 is a small capacitor used to prevent high frequency oscillation of the regulator. Capacitor 61-C3 is used to further filter the output of the regulator. Resistor 61-R10 is used to cause the base of 61-Q3 to see about the same source resistance as 61-Q2 for balanced circuit operation. Diode 61CR2 is used to bias the emitter of 61-Q1. Resistor 61-R3 is the current setting resistor for zener reference diode 61CR3. It receives its voltage from the 28 V. DC. regulator.
  • the operation of the 28 V. DC. regulator is very similar to the operation of the 2.5 V. DC. regulator and thus need not be explained.
  • the DC. stability of both regulators is excellent because of high quality reference type zener diodes and balanced differential amplifiers being used. This is important, because any change in the output of these regulators, especially the 2.5 V. DC. lam regulator, will change the sensitivity of the system due to a change in the light level. Changes in the output of either regulator will also cause noise problems, especially low frequency changes, because of the extended low frequency response of the relay driver amplifier.
  • transistors 61-Q11 to 61-Q14 and their interconnecting circuits can be eliminated, leaving only the driver transistor 61-Q4 and the power transistor 61Q5 connected to the circuits of transistors 61-Q1, 61- Q2 and 61-Q3 and to the bridge rectifier 61-CR1 in the manner indicated.
  • Yarn inspection apparatus for detecting broken yarns in a yarn sheet of plural substantially parallel yarns moving in a selected direction and lying in a feed plane, comprising a detector head located outwardly adjacent one edge of the yarn sheet having a light source and photodetector means therein and lens means for projecting light from said source in a narrow cross section monitor beam transversely spanning the yarn sheet and spaced in a direction perpendicular to said feed plane to one side thereof, retro-reflective target means located outwardly adjacent the opposite edgeof the yarn sheet having a sub stantially flat surface for retro-reflecting incident rays of said beam back along their incident ray paths to said detector head, semi-transparent mirror means for directing retro-reflected light entering said detector head onto said photodetector means, rectilinear elongated air discharge tube means supplied with pressurized air and having air discharge slot means facing said yarn sheet, said air discharge tube means paralleling said beam in substantially coextensive longitudinal relation thereto and being spaced from the opposite side of said
  • said knitting machine includes a plurality of yarn sheets extending downwardly along converging planes from said reed station to said needle station, said air discharge tube means and monitor beam having a pair of said yarn sheets disposed therebetween whereby the air discharged from said tube means blows any broken yarns from the yarn sheet nearest said tube means through the other yarn sheet of said pair and into said monitor beam.
  • said retro-reflective target means comprises a thin, substantially planiform target member including a sheet of retro-reflective material facing said detector head.
  • said target means includes a transparent glass plate covering the surface of said retro-reflective material facing said detector head, said glass plate being located in a plane inclined at a slight angle away from prependicular relation to incident light rays from said detector head to minimize reflection of such rays from surfaces of said glass plate to the lens of said detector head.
  • said target means comprises a thin, substantially planiform target member including a sheet of retro-reflective material facing said detector head and a transparent glass plate covering the surface of said retro-reflective material facing said detector head, said glass plate being located in a plane inclined at a slight angle away from perpendicular relation to incident light rays from said detector head to minimize reflection of such rays from surfaces of said glass plate to the lens of said detector head.
  • said target means comprises a thin, substantially planiform target member including a sheet of retrorefiective material facing said detector head and a transparent glass plate covering the surface of said retroreflective material facing said detector head, said glass plate being located in a plane inclined at a slight angle away from perpendicular relation to incident light rays from said detector head to minimize reflection of such rays from surfaces of said glass plate to the lens of said detector head.
  • said air discharge tube means include a motorized air blower having a pressurized air discharge, an elongated air discharge tube having said slot means extending substantially uninterruptedly along the length thereof, said tube spanning a selected portion of the yarn sheet adjacent the latter to propel air toward the yarns, and conduit means communicating said air discharge of the blower with plural locations along the length of said tube substantially symmetrically spaced relative to its longitudinal center and disposed substantially midway between the latter and the respective ends of said tube.
  • said air discharge tube means include a motorized air blower having a pressurized air discharge, an elongated air discharge tube having said slot means extending substantially uninterruptedly along the length thereof, said tube spanning a selected portion of the yarn sheet adjacent the latter to propel air toward the yarns, and conduit means communicating said air discharge of the blower with plural locations along the length of said tube substantially symmetrically spaced relative to its longitudinal center and disposed substantially midway between the latter and the respective ends of said tube.
  • said air discharge tube means include a motorized air blower having a pressurized air discharge, an elongated air discharge tube having said slot means extending substantially uninterruptedly along the length thereof, said tube spanning a selected portion of the yarn sheet adjacent the latter to propel air toward the yarns, and conduit means communicating said air discharge of the blower with plural locations along the length of said tube substantially symmetrically spaced relative to its longitudinal center and disposed substantially midway between the latter and the respective ends of said tube.
  • Yarn inspection apparatus as defined in claim 1, including mounting means for said detector head comprising a yoke having upwardly extending arms and a lower cross member, said detector head including a casing having trunnion members projecting oppositely therefrom along an axis lying transversely of the axis of said monitor beam, said yoke arms having means for journaling said trunnions for angular adjustment about their axis and means for locking the same at angular positions to which they are adjusted, a shock mount for said yoke having a cylindrical post rising therefrom, and said cross member having means journaling the same on said post for angular adjustment of said yoke about an axis perpendicular to the trunnion axis and means for locking said yoke at positions to which it is adjusted.
  • said lens means comprises a plane-concave lens disposed along a selected axis in alignment with said mirror and light source with its planar surface facing said mirror and light source, and a plane-convex lens spaced along said selected axis on the concave surface side of said piano-concave lens.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Treatment Of Fiber Materials (AREA)
  • Knitting Machines (AREA)
  • Looms (AREA)
US717076A 1968-03-29 1968-03-29 Yarn inspection apparatus Expired - Lifetime US3530690A (en)

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BE (1) BE730703A (de)
CH (1) CH478050A (de)
DE (1) DE1760853A1 (de)
FR (1) FR1598254A (de)
GB (1) GB1184168A (de)
NL (1) NL153615B (de)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3625243A (en) * 1970-02-13 1971-12-07 Singer Co Time cycle warp-stop motion control for weaving looms
US3628030A (en) * 1970-10-15 1971-12-14 Appalachian Electronics Instr Broken end detection system for warpers utilizing novel optical system
US3677307A (en) * 1969-06-27 1972-07-18 Georges P Fiorucci Arrangement provided with a photo-cell and controlling the detecting means and the stop motion in a loom upon breaking of a thread in the warping, weaving and knitting systems
US3687095A (en) * 1970-07-01 1972-08-29 Wilbur Jackson Tufting machine stop motion embodying light beam and sensor with triggering circuit responding to yarn breaks
US3731069A (en) * 1970-08-29 1973-05-01 Asahi Chemical Ind Apparatus for detecting yarn quality information
US3738124A (en) * 1971-04-08 1973-06-12 Deering Milliken Res Corp Knitting machine stop motion
US3740562A (en) * 1972-02-17 1973-06-19 Appalachian Electronic Instr Retro-reflective type detector head with fail-safe feature
US3842258A (en) * 1973-06-25 1974-10-15 Mekontrol Inc Photo relay comprising light-transmitting plate also used as a circuit board
US4300599A (en) * 1980-01-04 1981-11-17 Leesona Corporation Warp detection system
US4522139A (en) * 1983-07-25 1985-06-11 Spencer Wright Industries, Inc. Tufting machine broken yarn detector
US4538536A (en) * 1983-05-11 1985-09-03 Erwin Sick Gmbh Optik-Elektronik Optical apparatus for monitoring for thread breakage
US4549413A (en) * 1983-09-30 1985-10-29 Protechna Herbst Gmbh & Co. Kg Device for the photoelectric supervision of a warp loom
US4727732A (en) * 1986-02-13 1988-03-01 Campin Pierre G Device for detecting the presence of an individual yarn in a lap of parallel yarns
US5160850A (en) * 1991-01-14 1992-11-03 Walter J. Spirig Light beam interrupt detection apparatus for use in a vibrating environment
CN114232165A (zh) * 2021-12-16 2022-03-25 诸暨市嘉绍纺织有限公司 一种整经机及其控制方法

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DE4122305B4 (de) * 1991-07-05 2006-01-12 Sipra Patententwicklungs- Und Beteiligungsgesellschaft Mbh Vorrichtung zur optoelektronischen Abtastung eines Fadens
CN104957904B (zh) * 2015-06-29 2017-11-14 重庆欧荣莱汽车配件有限公司 一种提花沙发面料的加工设备
DE102015110519B3 (de) * 2015-06-30 2016-06-16 Protechna Herbst Gmbh & Co. Kg Überwachungseinrichtung zum Überwachen einer Fadenschar an einer Textilmaschine

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US2346240A (en) * 1943-03-23 1944-04-11 Celanese Corp Stop motion for knitting machines and the like
US2438365A (en) * 1944-11-17 1948-03-23 Alfred Hofmann & Company Stop means for textile apparatus and the like
US2464468A (en) * 1947-12-24 1949-03-15 Robbins Cloth Mills Inc Electric stop motion for textile machines
US2563906A (en) * 1948-01-08 1951-08-14 Celanese Corp Stop motion
US2570381A (en) * 1947-12-13 1951-10-09 Celanese Corp Stop motion for textile machines
US2711093A (en) * 1949-06-25 1955-06-21 Celanese Corp Stop motion
US3041461A (en) * 1958-05-27 1962-06-26 Lindly & Company Inc Photo electric inspecting apparatus
US3174046A (en) * 1961-09-05 1965-03-16 Lindly & Company Inc Photodynamic monitor for inspecting spun yarns
US3379225A (en) * 1965-05-31 1968-04-23 Toyo Boseki Loom stopping apparatus
US3401267A (en) * 1964-06-26 1968-09-10 Milton A. Engle Yarn breakage detector

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US2346240A (en) * 1943-03-23 1944-04-11 Celanese Corp Stop motion for knitting machines and the like
US2438365A (en) * 1944-11-17 1948-03-23 Alfred Hofmann & Company Stop means for textile apparatus and the like
US2570381A (en) * 1947-12-13 1951-10-09 Celanese Corp Stop motion for textile machines
US2464468A (en) * 1947-12-24 1949-03-15 Robbins Cloth Mills Inc Electric stop motion for textile machines
US2563906A (en) * 1948-01-08 1951-08-14 Celanese Corp Stop motion
US2711093A (en) * 1949-06-25 1955-06-21 Celanese Corp Stop motion
US3041461A (en) * 1958-05-27 1962-06-26 Lindly & Company Inc Photo electric inspecting apparatus
US3174046A (en) * 1961-09-05 1965-03-16 Lindly & Company Inc Photodynamic monitor for inspecting spun yarns
US3401267A (en) * 1964-06-26 1968-09-10 Milton A. Engle Yarn breakage detector
US3379225A (en) * 1965-05-31 1968-04-23 Toyo Boseki Loom stopping apparatus

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3677307A (en) * 1969-06-27 1972-07-18 Georges P Fiorucci Arrangement provided with a photo-cell and controlling the detecting means and the stop motion in a loom upon breaking of a thread in the warping, weaving and knitting systems
US3625243A (en) * 1970-02-13 1971-12-07 Singer Co Time cycle warp-stop motion control for weaving looms
US3687095A (en) * 1970-07-01 1972-08-29 Wilbur Jackson Tufting machine stop motion embodying light beam and sensor with triggering circuit responding to yarn breaks
US3731069A (en) * 1970-08-29 1973-05-01 Asahi Chemical Ind Apparatus for detecting yarn quality information
US3628030A (en) * 1970-10-15 1971-12-14 Appalachian Electronics Instr Broken end detection system for warpers utilizing novel optical system
US3738124A (en) * 1971-04-08 1973-06-12 Deering Milliken Res Corp Knitting machine stop motion
US3740562A (en) * 1972-02-17 1973-06-19 Appalachian Electronic Instr Retro-reflective type detector head with fail-safe feature
US3842258A (en) * 1973-06-25 1974-10-15 Mekontrol Inc Photo relay comprising light-transmitting plate also used as a circuit board
US4300599A (en) * 1980-01-04 1981-11-17 Leesona Corporation Warp detection system
US4538536A (en) * 1983-05-11 1985-09-03 Erwin Sick Gmbh Optik-Elektronik Optical apparatus for monitoring for thread breakage
US4522139A (en) * 1983-07-25 1985-06-11 Spencer Wright Industries, Inc. Tufting machine broken yarn detector
US4549413A (en) * 1983-09-30 1985-10-29 Protechna Herbst Gmbh & Co. Kg Device for the photoelectric supervision of a warp loom
US4727732A (en) * 1986-02-13 1988-03-01 Campin Pierre G Device for detecting the presence of an individual yarn in a lap of parallel yarns
US5160850A (en) * 1991-01-14 1992-11-03 Walter J. Spirig Light beam interrupt detection apparatus for use in a vibrating environment
CN114232165A (zh) * 2021-12-16 2022-03-25 诸暨市嘉绍纺织有限公司 一种整经机及其控制方法
CN114232165B (zh) * 2021-12-16 2022-08-12 诸暨市嘉绍纺织有限公司 一种整经机及其控制方法

Also Published As

Publication number Publication date
GB1184168A (en) 1970-03-11
BE730703A (de) 1969-09-01
DE1760853A1 (de) 1972-05-18
FR1598254A (de) 1970-07-06
NL6904693A (de) 1969-10-01
CH478050A (de) 1969-09-15
NL153615B (nl) 1977-06-15

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