Patent Publication Number: US-7909676-B2

Title: Independent measuring apparatus for grinding machines

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
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     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
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     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISK 
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     REFERENCE TO A MICROFICHE APPENDIX 
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     The present invention relates to an independent measuring apparatus for grinding machines. 
     BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     In particular, the invention relates to a measuring apparatus for cylinders, rolls and similar elements to be measured during the grinding operation, equipped with detection systems of the geometrical and dimensional characteristics (for example roundness, shape, diameter, etc.) and/or structural characteristics (for example, the presence of cracks and work hardening, measurement of the hardness, etc.) and/or surface characteristics (for example roughness, states of surface tension, etc.). 
     II. Description of Related Art 
     Grinders of cylinders coming from rolling mills, for the production of strips of metallic material, are large dimensional machines which must guarantee high performances in terms of repeatability and accuracy of the measurements effected in addition to precision in revealing the geometrical shapes obtained. 
     These characteristics relating to precision, surface quality and repeatability to be guaranteed on a wide range of dimensions (in diameter—up to and over 2 m—and in length—up to and over 10 m), are required in a whole range of sectors in addition to the rolling of flat metallic and non-metallic products, such as the paper and printed paper industry, the constructions of engines and large dimensional hydraulic systems, for example pistons, transmission shafts and elbow shafts for marine engines. 
     The use of these machines is generally indispensable whenever the large dimensions of elements are associated with sophisticated and restrictive geometrical and surface characteristics as well as structural integrity. 
     In the iron and steel industry, for example, it is common practice for the reconditioning operations of cylinders from rolling mills to be effected in areas adjacent to the rolling mill itself called “cylinder shapers” or in workshops dedicated to the service of various rolling mills. In these spaces, worn and/or damaged cylinders converge to be subjected to a grinding phase suitable for restoring the ideal conditions necessary for the rolling process. 
     Even tiny variations in the theoretical profile and roundness of the rolling cylinders cause undulations in the strips, surface marks and traces which reduce the commercial value of tons of steel, with obvious damage to the plant which produces and commercializes them. Furthermore, deviations in the roughness requested cause problems in the subsequent surface protection phases of the strip. Finally, small surface defects (such as, for example cracks, work hardening etc.) jeopardize the structural integrity of the cylinder increasing the risk of accidents (for example catastrophic breakages) causing production blockages and enormous repair expenses, naturally also in addition to the most important aspect linked to the safety of the operators. 
     In order to optimize the reconditioning procedure of the cylinder, it is necessary to measure and subsequently correct its geometry during the grinding process. At the same time, it is necessary to identify the entity and position of defects in order to effect suitable grinding actions for eliminating them. 
     The present state of the art defines two alternative solutions for measuring these cylinders:
         in the paper industry systems have been developed based on 4 points capable of giving an excellent qualitative response with respect to the determination of the roundness characteristics of the cylinder. This solution, however, has the limitation of being assembled on the wheel-holder trolley and consequently operating in synchronization therewith. This implies that, with respect to the quality of the detection, the geometrical measurements and dimensions are satisfactory but cannot be effected during the grinding cycle whereas the structure and surface faults are subject to sampling. The various dimensions of the grinding wheel and sensors envisage that the measurement coil be of a lesser width than that generated by the grinding wheel, making it impossible for the sensor to cover the whole area to be analyzed. As this is consequently a non-exhaustive measurement, an identification of all the faults is not guaranteed;   in the iron and steel industry, on the contrary, alongside the synchronous “traditional” measurement methods (gauge assembled on board the wheel-holder trolley) but with a geometrical and dimensional analysis effected with two sensors which have the same limitations described above, solutions have been developed based on asynchronous detection methods (independent gauge) which operate on two points to effect geometrical and dimensional measurements (shape, profile, diameter, etc.).       

     Regulations (for example ISO 4292) establish that a complete and exhaustive measuring of the roundness must be carried out with two measurements on three points and one on two points and that these determinations must be effected independently of each other. It is therefore evident that the procedure and equipment currently on the market are not capable of providing exhaustive measurements. These apparatuses, on the other hand, are perfectly adequate for determining the structural and surface characteristics, as an asynchronous system adapts the pitch of the coil with the dimension of the sensors. 
     In the “traditional” cycle (synchronous), three phases are necessary for obtaining an exhaustive analysis of the whole processing area:
         passage of the grinding wheel,   geometrical and dimensional and, optionally, structural control,   definition of the new processing parameters.       

     These operations must be carried out sequentially increasing the cycle time required. 
     Furthermore, the fact of operating in different times, induces possible errors due to variations in the configuration of the system as a result of accidental events between the two passages. 
     BRIEF SUMMARY OF THE INVENTION 
     A general objective of the present invention is therefore to provide a measurement apparatus for grinding machines suitable for overcoming the above drawbacks of the known art described above by introducing the measurement of the geometrical characteristics with 4 detection points which, among other things, responds to the requisites defined in the ISO regulations and operating, together with “structural” and/or “surface” sensors, on an asynchronous movement system. 
     This system is therefore also capable of operating contemporaneously with the grinding of the cylinder. 
     In view of the above objectives, according to the present invention, an independent measuring apparatus has been conceived for grinding machines, in particular a measuring apparatus for cylinders, rolls and the like, to be subjected to grinding, equipped with geometrical and/or dimensional and/or structural and/or surface control organs having the characteristics specified in the following claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The drawing shows a diagram of a grinding machine for cylinders, rolls and similar elements. 
       The morphological and functional characteristics of the present invention as also its advantages with respect to the known art will appear more evident from the following description, referring to the enclosed FIGURE which offers a non-limiting example of the invention and which schematically illustrates an independent measuring apparatus for grinding machines produced according to the innovative principles of the invention itself. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With reference to the FIGURE, a grinding machine  10  for cylinders  11 , rolls and similar elements comprises at least one base  12  along which a grinding trolley  20 , carrying the grinding unit  21  equipped with a grinding wheel  22 , and a supporting trolley  40  of the independent gauge carrying a measuring apparatus  50 , are moveably supported. 
     The measuring and detection apparatus  50  of the geometry of the cylinder  11  is used not only for cylinders coming from the rolling mill, to obtain strips made of metallic material, but also in other sectors comprising grinding processing of cylinders, rolls and other similar elements for the paper industry and, more generally, of flat non-ferrous rolled sections and/or fields such as the construction of marine engines and/or large dimensional hydraulic systems. 
     The measuring and detection apparatus  50  is therefore assembled on an independent system, the measuring trolley  40 , and, as a first specific characteristic, is produced with a structure  51  similar to tongs, equipped with at least one upper arm  52  carrying upper sensors  54  and a lower arm  53 , carrying at least one lower sensor  55 . 
     The measuring apparatus comprises at least four sensors and two arms. 
     This tong-like structure is designed to be opened/closed, by the translation and/or rotation of at least one of the arms  52 ,  53 , in the direction indicated with the arrow F, so as to come into contact with the cylinder  11  during the measuring phase, at the same time, allowing it to be loaded and unloaded at the end of the processing. 
     The measuring apparatus  50  also has sensors  54 ,  55  positioned so as to effect a simultaneous measuring in at least four points, without any interference on the part of the grinding unit. 
     In particular, the upper sensors  54  are arranged along a suitable support  56  and are radially positioned on a perpendicular plane with respect to the axis of the cylinder  11  being processed. 
     One of the remaining sensors or lower detection points  55 , also radial, can be situated in a diametrally opposite position to one of the positions of the upper sensors  54  of the support  56  and consequently also on a perpendicular plane with respect to the axis of the cylinder being processed in order to guarantee a direct reading of the diameter of the cylinder  11 . 
     In other words, the measuring system according to the invention operating on a machine for the grinding of said cylinders with an autonomous movement, i.e. with a movement independent of the translation movement of the grinding wheel or other parts, comprises at least four sensors ( 54 ,  55 ), situated on a plane orthogonal to the cylinder ( 11 ) or roll and two of said sensors can be situated in positions diametrally opposite to each other. 
     The sensors are therefore positioned on at least two arms  52 ,  53  equipped with automatic movement means which allow the sensors  54 ,  55  to approach and be roughly positioned on the surface of the cylinder  11 . 
     The fine regulation is then managed by directly using the signals coming from the sensors. 
     In addition to the sensors  54 ,  55  cited above, it is also possible to add detection systems of structural faults, such as parasite, currents and/or ultrasounds and/or durometers, and/or rugosimeters and similar systems for determining the surface characteristics. 
     This structural and/or surface analysis system is envisaged as being installed on the structure of the independent gauge  51  or on another dedicated structure, again situated on board the independent gauge. 
     Suitable rest supporting structures  60  carrying skids  61  are also envisaged on the base  12  to support the cylinder being processed. 
     The system obviously functions even if the cylinder is supported between the grinding points (centres), without any help of rests. 
     The presence of the sensors  54 ,  55  advantageously enables, if assisted by a specific algorithm implemented in the automatic management system of the grinding machine  10  and a suitable measurement strategy, the complete characterization of the roundness. 
     This allows a complete geometrical plotting of the cylinder  11 , producing a base on which the subsequent grinding operations can be optimized by means of a suitable information processing and feedback system on the processing parameters of the grinding wheel adjusting the roundness, profile, diameter and conicity of the ground cylinders.