Optics: measuring and testing – Inspection of flaws or impurities – Textile inspection
Patent
1996-09-16
1998-06-16
Font, Frank G.
Optics: measuring and testing
Inspection of flaws or impurities
Textile inspection
356430, 2505594, 242 36, 226 10, 226 45, G01N 2100, G01N 2184, B65H 6300, B23Q 1500
Patent
active
057679630
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a method of detecting a yarn wind (or lap) on a rotating roll, as well as to a device for carrying out this method.
It is known to determine the diameter of a package, in particular a package of a synthetic yarn, by means of a pivotally arranged sensor roll. To this end, the sensor roll rests against the package being wound and rotates along with same. Should an interference with the yarn occur in the region of the sensor roll, the yarn may be wound on the sensor roll. Such an unwanted yarn wind leads to a breakdown of the operation. The breakdown may also lead to a malfunction of a yarn traversing mechanism upstream of the winding head or takeup unit, and cause, within a short period of time, considerable damage to the yarn takeup unit as a result of a rapidly increasing volume of the yarn winds on the sensor roll.
To minimize the extent of the breakdown in the operation and damage, it has been proposed already to provide a sensor plate tangential to the sensor roll. Since the sensor roll vibrates, it is necessary to provide an air gap between the sensor roll and the sensor plate. To make sure that the sensor plate does not trigger false alarms under all operating conditions, the air gap must be made accordingly large. This leads to the disadvantage that a noticeable amount of yarn winds must have formed on the sensor roll, so that the sensor plate releases an alarm signal.
With respect thereto, it has already been proposed to provide a light barrier, which is arranged parallel to the sensor roll of the takeup unit. Should now a yarn wind about the sensor roll, the amount of light received is changed by the lap. Should this amount fall below a predetermined value (photocurrent), an alarm signal will be released.
However, this solution fails to take into account that the sensor roll vibrates. The vibrations of the sensor roll develop as a result of radial oscillations, which result from inaccuracies of roundness, as well as from bendings or from pressure on the yarn packages. Likewise, such vibrations may result from a play in the bearing, transfer of imbalance and vibration by yarn packages resting thereagainst.
As a result, even this solution fails to provide a satisfactory monitoring of the sensor roll or contact roll.
Finally, for purposes of monitoring selected axial portions of a rotating contact roll or sensor roll with respect to yarn winds, it is known from U.S. Pat. No. 4,188,545 to direct from a source of light arranged at a radial distance above the roll, a light beam to a monitoring range of the roll at an angle from 0.degree. to 90.degree. , to capture the reflected light by a light-sensitive sensor, and to convert same into an electric signal. Changes in the intensity of the reflected light or the stray light caused by an undesired wind are measured, evaluated, and used for actuating a yarn cutting device.
Disadvantageous in the known method, which forms the basis of the invention, is that the monitoring range is substantially punctiform, and that the entire length of the roll of the takeup unit can be monitored only with a large amount of technical resources. However, this is necessary, should an undesired yarn wind or lap form, for example, in the instance of a shut down traversing mechanism, on a section of the shaft that is not monitored. It is possible, though, to even detect such undesired yarn winds with the use of a plurality of light sources and detector arrangements, which extend along the roll, or, in the alternative, by reciprocating the light source and the light-sensitive sensor arrangement. However, this causes the time of response of the system to become extremely long, and makes the monitoring method unsuitable for high winding speeds. In addition, along with a contamination of the roll surface, the reflection properties deteriorate, and a stable adjustment of the operating point is made difficult, thereby limiting considerably the operational reliability of the known device.
It is therefore the object of the present inve
REFERENCES:
patent: 3712743 (1973-01-01), Harris et al.
patent: 4108708 (1978-08-01), Gregory et al.
patent: 4188545 (1980-02-01), McClean et al.
patent: 4866289 (1989-09-01), Kawamura et al.
patent: 5029762 (1991-07-01), Behrens et al.
patent: 5420439 (1995-05-01), Landwehrkamp et al.
patent: 5590547 (1997-01-01), Couzelmann
Barmag AG
Eisenberg Jason Vierra
Font Frank G.
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