Optics: measuring and testing – By polarized light examination – With light attenuation
Reexamination Certificate
1999-12-15
2001-09-18
Font, Frank G. (Department: 2877)
Optics: measuring and testing
By polarized light examination
With light attenuation
C072S021100, C072S011600, C073S037000
Reexamination Certificate
active
06292262
ABSTRACT:
FIELD OF THE INVENTION
This invention concerns a method and the relative device to measure the gap between two or more substantially static elements whose reciprocal position may be variable with respect to a pre-defined reference value, as set forth in the relative main claims.
The invention allows to measure, via optical means, the transit gap defined between two or more elements, in order to provide the worker with the instructions necessary to regulate, in an extremely rapid and precise manner, the position of the elements so as to predispose them for subsequent use.
The invention also allows to control the congruity of the profile of the actual gap with respect to a pre-set reference model.
The invention is suitable to be used in particular, though not exclusively, in the metallurgical field in order to regulate, according to a pre-defined setting mask, the gap between two rollers of a guide box for rolled stock, or the gap between the rolls of a rolling stand, or to verify the alignment between two or more boxes, between the box and the relative stand or between two or more stands. In the following description, for the sake of simplicity, we shall refer to this particular application, but this shall not be restrictive for the invention.
BACKGROUND OF THE INVENTION
In many different fields, the state of the art includes the need to position two or more elements in a reciprocal, pre-set position defining a transit gap, with an extremely high level of precision.
In the metallurgical field, for example, the state of the art covers the need to regulate the position of the shaped rollers of the boxes which guide the rolled stock in order to adapt the gap which they define to the section of rolled stock which has to be guided, or to regulate the position of the shaped working rolls in rolling stands in order to gauge the gap which they define so as to produce rolled stock of the pre-set section, with extremely limited margins of tolerance.
At present, these regulations are done manually by the workers using specific equipment and conventional measuring methods, which are not very precise or reliable.
Measurements made with traditional methods, moreover, must be repeated by the worker several times during the regulation of the rollers or rolls, until the pre-set parameters are achieved.
It is a well-known practice to make the measurements by means of a viewer, which uses an opalized screen and a system of optical amplification to monitor the profile and the dimension of the transit gap defined between two rollers or rolls. However, this system is also manual and does not ensure a reliable result.
At the present time, then, it is extremely complicated to measure and regulate the gap and the alignment between two variable-position elements, in this case rolls and rollers, and it requires a lot of time and specialised staff.
The speed of performance and the results obtained, moreover, are closely connected to the worker, his experience and the technique he uses. FR-A-2.641.373 discloses a distance measuring device to measure the deformations of an object which is rotating at high speed in a vacuum container due to the centrifugal forces acting thereon.
The device comprises a light-emitting element consisting of a stroboscope, whose emission frequency is synchronized to the speed of rotation of the object, a first lens on which the real image of the object obtained with every emission of a stroboscopic impulse is reproduced, a graduated grid on which the real image is superimposed, and a second lens, with an enlarging function, arranged on the other side of the grid with respect to the first lens.
The solution proposed by FR '373 is complex because it requires two distinct lenses, one to represent the rotating object on a scale of 1:1 and one to enlarge the image, and a grid located between the two lenses to visually quantify the deformation of the object.
Moreover, this solution entails an intrinsic difficulty of synchronizing the stroboscopic light and the speed of rotation of the object.
Furthermore, the deformation has to be visually quantified and interpreted on the grid, and is therefore subjective, not very precise, and not very reliable.
This solution therefore does not overcome the problems of the state of the art as explained above.
The present Applicant has designed and embodied this invention to overcome this shortcoming which many people complain of in the state of the art, and particularly in the metallurgical field, and also to obtain further advantages as will be shown hereafter.
SUMMARY OF THE INVENTION
The invention is set forth and characterised in the respective main claims, while the dependent claims describe other characteristics of the invention.
The main purpose of the invention is to provide a method and the relative device to measure and regulate the transit gap defined between variable-position elements so as to simplify, accelerate and standardise the operations to set and predispose these elements according to the value required by the working specifications.
Another purpose of the invention is to carry out extremely precise measuring operations which will be immediately available to the workers in numeric form, and therefore entirely without possible errors of interpretation and evaluation by the workers, so as to guide them progressively in the setting and pre-arranging operations.
A further purpose of the invention is to render the measurements independent of the worker and therefore to allow even non-specialised or inexperienced workers to position and regulate the aforesaid elements.
Another purpose is to provide equipment of a size which can be transported and easily installed in any working environment whatsoever, simple to prepare and to work since it does not need any complicated procedures of synchronization or fine-tuning.
The device according to the invention comprises, in its essential parts, visual recording means consisting of at least a TV camera connected to a processor suitable to receive and process the images filmed by the TV camera.
In one embodiment of the invention, the TV camera cooperates with a light source suitable to increase the definition of the images filmed.
According to a preferential embodimient, the light source is aligned with the TV camera and is located on the opposite side of the TV camera, with respect to the elements to be filmed.
The method according to the invention provides to align the TV camera with the transit gap defined between the elements to be regulated, and to compare the images filmed by the TV camera with a defined sample mask, or setting mask.
The sample mask can be selected by the worker from among those contained in an archive in the processor, or can be acquired by the processor by means of a previous gauging procedure.
In one embodiment of the invention, the sample mask consists of a digital image. According to a variant, the sample mask consists of a drawing made with a CAD program.
The invention allows to provide automatically to the operator, in real time and continuously, all the information, or data, concerning the differences found by the processor between the image filmed by the TV camera and the sample mask.
To be more exact, the data is expressed and displayed as numerical values relating to the discrepancies on every dimension, such as for example height, width, interaxis, etc., between the image filmed by the TV camera and the sample mask used as setting, preparation and comparison datum.
According to a variant, the processor also provides information on the congruity of the profile of a part or all of the image filmed with respect to the profile of the sample mask, in the event that the transit gap subjected to gauging defines a particular geometric profile, as happens for example with the rolls of rolling stands.
According to one characteristic of the invention, this information is immediately and continuously made available to the worker by means of interface means, such as for example a monitor.
With the method according to the invention, therefore, it is possible to guide t
Ciani Lorenzo
Della Vedova Ferruccio
Centro Automation SpA
Font Frank G.
Nguyen Sang Hoang
Stevens Davis Miller & Mosher L.L.P.
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