DEVICE FOR OPTICAL YARN MEASUREMENT

Abstract: The invention relates to a device for contactless measurement of a linear textile formation such as yarn, thread, textile fibre, sliver, etc. containing a radiation source (6) and a radiation sensor (reader) (7) consisting of a system of radiation sensitive elements (700). The radiation sensor (7) consists of a CMOS optical sensor (70).

Description: DEVICE FOR OPTICAL YARN MEASUREMENT Technical field The invention relates to a device for contactless measurement of a linear textile formation such as yarn, thread, textile fibre, sliver, etc. containing a radiation source and a radiation sensor consisting of a system of radiation-sensitive elements. Background of the invention There are known devices for contactless measurement of a linear textile formation such as yarn, thread, textile fibre, sliver, etc. containing a light radiation source and a light radiation sensor made as a CCD sensor comprising a plurality of radiation-sensitive elements situated either next to each other or in matrix configuration. In spite of the advantages reached by the application of the CCD sensors in such devices, their drawbacks consist in the still relatively high costs of the CCD sensors and in their limited sensing velocity due to the principle of their function based on the accumulation and transmission of the electric charge. The aim of the invention consists in reducing the costs of the device for contactless measurement of a linear textile formation such as yarn, thread, textile fibre, sliver, etc. and in permitting to improve the parameters of the contactless measurement of a linear textile formation such as yarn, thread, textile fibre, sliver, etc. Principle of the invention The aim of the invention has been reached by a device for contactless measurement of a linear textile formation such as yarn, thread, textile fibre, sliver, etc., whose principle consists in that the radiation sensor consists of a CMOS optical sensor. The advantage of this device consists in lower costs of the CMOS optical sensors as compared with the CCD sensors. Another advantage of the device consists in the sensing velocity of the CMOS optical sensor, superior to that of the CCD sensor, and in the fact that the output signal can be processed better and simpler than the output signal of the CCD sensor. Like the device using the CCD radiation sensors, the device according to the invention can be used for determining both the thickness of a moving linear textile formation by evaluating the irradiation state of the elements of the CMOS optical sensor and for determining the homogeneity of a moving linear textile formation by evaluating the irradiation state of the elements of the CMOS optical sensor. These two variants can be combined at will for obtaining more exact results of the monitoring of the thickness and/or of homogeneity of a moving linear textile formation, and their use depends especially on the type and the properties of the monitored linear textile formation and on the technological needs and possibilities of the device used for the monitoring. The device is intended for mass application in textile machines, in particular in spinning and winding machines. Another advantage of CMOS optical sensors over CCD sensors working on the principle of the electric charge coupling consists in the substantially higher resistance of the CMOS optical sensors, as compared with the CCD sensors, to the mutual influence exerted by the neighbouring radiation-sensitive elements. This is due to the fact that in the CCD sensors the electric charge passes to an extent between the neighbouring radiation-sensitive elements and thus impairs the measurement precision. If, for instance, one of the two neighbouring radiation- sensitive elements is irradiated fully whereas the other only a little or not at all, a part of the electric charge can pass from the fully irradiated (illuminated) radiation- sensitive element into the neighbouring poorly irradiated (illuminated) element so that the apparent irradiation of the poorly irradiated (illuminated) element disclosed on the measuring device is superior to its actual irradiation. For the evaluation of the parameters of the linear textile formation at favourable costs and sufficient measurement precision, the CMOS optical sensor preferably contains at least one row of radiation-sensitive elements situated next to each other. For easier processing of the output signal of the CMOS optical sensor and for virtual measurement of a larger section of the measured linear textile formation the CMOS optical sensor preferably contains at least one row of radiation-sensitive elements whose dimension in the direction of the length of the row of radiation- sensitive elements is inferior to their dimension in the direction perpendicular to the length of the row of radiation-sensitive elements. Description of the drawing Examples of embodiment of the device according to the invention are schematically shown in the accompanying drawing in which Fig. 1 is an axonometric view of the device with a CMOS optical sensor of radiation, Fig. 2 is a section of the device of Fig. 1 in the sensing plane, Fig. 3 is a section of a device comprising a point source of radiation in the sensing plane, and Fig. 4 is a section in the sensing plane of an embodiment in which the plane passing through the axis of the linear textile formation and through the radiation source forms an acute angle with the representation plane. Specific description The device for contactless measurement of a linear textile formation such as yarn, thread, textile fibre, sliver, etc. will be described in more detail on examples of embodiment for determining the thickness and/or homogeneity of yarn. In the whole text of this specification, homogeneity is intended to mean mass uniformity. Since the core of yarn 1. is opaque, the yarn homogeneity is monitored in the circumferential part of the yarn 1. In the whole text of this specification, thickness is intended to mean diameter uniformity. In the shown example of embodiment, the moving linear textile formation consists of the yarn 1 which is in a well-known manner delivered from a well-known spinning device 2. The yarn 1 is delivered by a well-known delivery device which in the shown embodiment functions also as a first stabilization means 3 of the path of the yarn 1 consisting in the shown example of embodiment of guiding rollers. Inserted into the path of the yarn ± is in the shown embodiment a second stabilization means 4 consisting in the shown example of embodiment also of guiding rollers out of which the yam 1 is led in the direction of the arrow 0 to well-known not represented means for winding the yarn 1 on a bobbin. The stabilization means can consist also of other suitable yarn guiding means, or the stabilization means can be dispensed with altogether. Between the two stabilization means 3, 4, the yarn 1 passes through a radiation flux 5 emitted by a radiation source 6 made in the embodiment shown in Fig. 1 as a point radiation source 60. Situated opposite the radiation source 6 is a radiation sensor 7 consisting of a CMOS optical sensor 70 fitted with a plurality of radiation-sensitive elements 700 arranged next to each other substantially normal (perpendicular) to the direction of the motion of the measured linear textile formation. Each of the plurality of the radiation-sensitive elements of the CMOS optical sensor 70 is coupled with an evaluation device 8 of the state and/or degree of its irradiation. The evaluation device 8 can be made as an integral part of the CMOS optical sensor 70. The evaluation device 8 is able to evaluate the function of the CMOS optical sensor 70 and is fitted with an output 80 of information on the monitored parameters of the yarn 1 measured by the CMOS optical sensor 70, in particular on the thickness, hairiness, etc., of the yarn Λ . Depending on the specific needs of the case, the output 80 of the evaluation device 8 can be connected with means for further processing the data determined by the CMOS optical sensor 70, for instance with the control system of the machine or of the operating unit and/or with a displaying device and/or with a recording device and/or with regulation means of the operating unit of a machine and/or with control means of the operating unit intended to interrupt the motion of the yarn and/or to stop at least some of the functional components of the operating unit of the machine, etc. In a not shown example of embodiment, the device for the contactless measurement of a linear textile formation can be fitted with a suitable control device and/or with a feedback control system for controlling the intensity of the radiation emitted by the radiation source 6. The point source 60 of radiation emits radiation and generates a radiation flux 5 falling on the radiation-sensitive elements 700 of the CMOS optical sensor 70. The path of the yarn Λ intersects the radiation flux 5. A sensing plane 50 passes through the point source 60 of radiation and through all radiation-sensitive elements 700 of the CMOS optical sensor 70. The yarn lying in the radiation flux 5 and moving in the direction of its longitudinal axis overshadows some of the elements 700 of the CMOS optical sensor 70 that receives the radiation, and the state of irradiation of each of the radiation- sensitive elements 700 and/or the degree of their irradiation is suitably used for calculating and/or evaluating the monitored parameters of the yarn 1. such as its thickness and/or hairiness, homogeneity of the sliver, dimension of the core of moving core thread, etc. The device for contactless measurement of a linear textile formation such as yarn, thread, textile fibre, sliver, etc. shown in the drawing can be further modified so as to meet the specific needs of some technological processes while maintaining the positioning of the elements 700 in a straight line lying in the sensing plane 50, not parallel with and having no common point with the path of the moving yarn as it is in the section of the sensing plane 50 with the point source 60 of radiation according to Fig. 1 shown in Fig. 2. The point source 60 of radiation is situated in a plane passing through the longitudinal axis of the yarn and normal (perpendicular) to the straight line in which the elements 700 of the CMOS optical sensor 70 are located. The radiation emitted by the the point source 60 of radiation falls on the CMOS optical sensor 70 in rays 600 diverging from the point source 60 of radiation. Fig. 3 shows another modification of the device according to Fig. 1 in the section of the sensing plane 50. In this modification, the point source 60 of radiation is replaced by a straight line source source 6_1 of radiation. The radiation flux 5 consists of parallel rays so that this embodiment is suitable in particular for considerably thick yarns 1 or other linear textile formations because the picture of the yarn \ appearing on the radiation sensor 7 consisting of a plurality of radiation-sensitive elements 700 is equal to the thickness of the linear formation lying in the radiation flux 5. For technological reasons, it is sometimes suitable to locate the point source 60 of radiation outside the plane normal to the radiation sensor 7 and passing through the longitudinal axis of the linear textile formation, as is shown in Fig. 4. Since the velocity of the motion of the yam Λ or of another linear textile formation is in most cases known and the evaluation process of the state and/or degree of irradiation of the radiation-sensitive elements 700 takes a time interval, the monitoring of the thickness and/or homogeneity of the yarn 1 by this method is discontinuous even if it permits a higher sampling speed of the linear textile formation in question. In spite of this, it provides exact information on the real thickness and/or homogeneity of the yarn or of another linear textile formation in the sensing planes following each other. The distance between the sensing planes 50 is in stabilized state as a rule constant but it can vary, for instance it can decrease in response to the detection of a sudden change in the thickness and/or homogeneity of the yam Λ . To simplify the signal processing in measuring the parameters of the linear textile formation and for virtual measurement of a larger section out of the total length of the measured linear textile formation, the CMOS optical sensor can be made of rectangular-shaped radiation-sensitive elements 700 so arranged that their smaller dimension is perpendicular to the direction of motion of the measured linear textile formation, i.e., in the direction of the length of the row of the radiation-sensitive elements 700, and that their greater dimension is situated in the direction of motion of the measured linear textile formation, i.e., in the direction normal to the length of the row of the radiation-sensitive elements 700. Due to this, the radiation-sensitive elements 700 are during the measurement of the linear textile formation situated with their smaller dimension in the direction of the thickness of the measured linear textile formation, and with their greater dimension in the direction of the length of the measured linear textile formation. The device for contactless measurement of a linear textile formation such as yarn, thread, textile fibre, sliver, etc., can be on each operating unit of a textile machine controlled by a control unit of the operating unit which can also evaluate and process the measured values of the parameters of the linear textile formation. Analogically, on each operating unit of a textile machine, the evaluation device 8 of the device for contactless measurement of a linear textile formation can in addition to its own function consisting in the measurement of a linear textile formation ensure also the activities of the control unit of the operating unit of a textile machine.

Claims: PATENT CLAIMS 1. A device for contactless measurement of a linear textile formation such as yarn, thread, textile fibre, sliver, etc. containing a radiation source and a radiation sensor (reader) consisting of a system of radiation-sensitive elements characterized by that the radiation sensor (7) consists of a CMOS optical sensor (70). 2. A device as claimed in Claim 1, characterized by that the CMOS optical sensor (70) contains at least one row of radiation-sensitive elements (700) situated next to each other. 3. A device as claimed in any of Claims 1 and 2, characterized by that the CMOS optical sensor (70) contains at least one row of radiation-sensitive elements (700) situated next to each other whose dimension in the direction of the row of the radiation-sensitive elements (700) is smaller than their dimension in the direction normal to the direction of the row of the radiation-sensitive elements (700)

Inventors: HAJEK LADISLAV, KOUSALIK PAVEL, STUSAK MIROSLAV, HAJEK, LADISLAV, KOUSALIK, PAVEL, STUSAK, MIROSLAV
Applicants: HAJEK LADISLAV, KOUSALIK PAVEL, RIETER CZ AS, STUSAK MIROSLAV, HAJEK, LADISLAV, KOUSALIK, PAVEL, RIETER CZ A.S., STUSAK, MIROSLAV
Application year: 2001
Main classification: G01B11
IPC codes: G01B11