Title of Invention

AN IMPROVED SYSTEM FOR FLATTENING OF COLD ROLLED STRIPS.

Abstract

AN IMPROVED SYSTEM FOR FLATTENING OF COLD ROLLED STRIPS WITHOUT USE OF MOTOR AND MULTI OUTPUT GEARBOX AS THAT REQUIRED IN KNOWN CONVENTIONAL LEVELLER COMPRISING THRUST BEARING ARRANGEMENT ASSEMBLED WITH RESPECT TO THE WORKING ROLLS OF SAID LEVELLER FOR PREVENTING SIDE THRUST. THE SYSTEM OF THE INVENTION FURTHER AVOIDS THE REAUIREMENT OF MOUNTING ON LINE OR OFF-LINE OF THE LEVELLER AND INSTEAD PROVIDES FOR IMPROVED CHASSIS FOR SUPPORTING THE DIFFERENT COMPONENTS WITH SAID LEVELLER ADAPTED TO BE FIXED TO THE GROUND THROUGH SAID CHASSIS. THE IMPROVED SYSTEM THUS PROVIDES FOR A FIRM FOUNDATION AND RIGIDITY AND FACILITATE THE IMPROVED FALTTENING OF STRIPS. THE SYSTEM IS SIMPLE TO OBTAIN AND USE AND IS ALSO AT THE SAME TIME COST EFFECTIVE.

Full Text

The present invention relates to a system for improving the flatness of cold rolled strips and a process for manufacture of levelled strips using the system of the invention. For improvement in flatness of steel it is necessary to stretch the material beyond its yield point. When strip is bent around a roll, compressive-stresses are established in layers of the strips surface adjacent to the roll and the tensile stress on the opposite side. So long as the roll diameter to strip thickness (D/t) ratio is sufficiently large, these stresses produce only elastic strains which disappear when the bent portion of the strip is moved past the roll. However, as the roll diameter to strip thickness ratio is decreased, a point is reached vvhere the stresses are such that plastic deformation occurs and a coil shape is given to the strip. For achieving the same strip is passed through a set of rolls and the strip is imparted a requisite tension. It is conventionally known to use leveller equipment for improving flatness of coid rolled strips. The invention is described hereunder in relation to the accompanying figures wherein Figs. 1, 2, 3, 4, 5 illustrate in detail the thrust bearings provided in the improved system for the upper an8 lower rollers. Fig. 2 illustrates the modification in the non-drive side of the upper rollers in the system of the invention. Fig. 3 illustrates the modifications in the drive side for the upper rolls in the system of the invention. Fig. 4 illustrates in greater detail the modifications at the non-drive end of the upper rolls in the system of the invention. Fig. 5 illustrates the modifications in the drive side end of the tower rolls in the system of the invention. Fig. 6 shows conventional leveller equipment. Fig. 7 is a schematic illustration of the improved system for levelling and cold rolled strips in accordance with the present invention. Fig. 8 illustrates the modified chassis used in the system of the invention. Fig. 9 illustrates the modification in the leveller roll end of the system of the invention. Figure 10 illustrated the position of the levellers on/off line depending upon the end use requirement. The known leveller equipment presently in use as illustrated in accompanying Fig. 10 is usually mounted online or offline as and when required. Usually two varieties of such equipments are in use one is for thin gauge (0.3-0.8mm) and the other is for a thick gauge (0.8-2.5 mm). Depending upon the size of the strip the equipments are usually selected. As would be evident from the Fig. 6, such conventional leveller equipments comprise fixing brackets (1) for fixing with the foundation, chassis (2) to support different components, pinch rolls (3) in pinch roll housing (4), screw down motors (5) are provided to drive the screw down mechanism which in turn exerts vertical force to the strips through rolls (6). Working rolls (6) strengthen and flatten the strip. The front guard (7) is provided to prevent the shifting of the assembly. The known leveller usually consist of 17 number of rolls or 21 number of rolls and are driven by the motor (10) operatively connected to gear box (9) and multi shaft coupling for driving of the rolls. It is the basic object of the present invention to provide for an improved system for use in flattening cold rolled strips without requirement of motor and multi output gearbox as that conventionally use in known levellers. Another object of the present invention is to provide for a system which could have desired number of working rollers for strengthen and flattening of the strips depending upon the strip characteristics. Yet further object of the present invention is to provide for a system for flattening of cold roll strips which would be simple to obtain, use and at the same time would be cost effective. Yet further object of the present invention is to provide for an improved system for flattening of cold rolled strips which would have a firm foundation and rigidity and facilitate improved flattening of strips. Yet another object of the present invention is to provide an improved system wherein the drive is removed as the strip is continuous and tension provided by the coiler and uncoiler. Yet another object of the present invention is to provide for a process for flattening of cold rolled strips utilising the system of the invention. Thus according to one aspect of the present invention there is provided an improved system for flattening of cold rolled strips comprising : working rolls comprising upper and lower working rolls adapted to allow passage of the strip to be flattened therebetween ; screw down motors operatively connected to screw down mechanism adapted to exert vertical force to the strip through said working rolls ; means for guiding of the strip through therebetween said upper and lower working rolls ; thrust bearing arrangement assembled with respect to said working rolls for preventing side thrust. In accordance with the above improved system for flattening of cold rolled strips in accordance with the present invention the same achieves the following distinguishing features in relation to the conventional levellers. a) The drive system of the conventional levellers have been removed and thrust bearing have been provided. b) Wheels have been removed from the leveller equipment and the provision of fixing of the system to the ground through chassis provide for better stability and rigidity to the system. c) Thrust bearings have been provided to prevent side thrust. d) Modifications in the roll end portions have been effected to facilitate fixing to the thrust bearings. The details of the invention its objects and advantages are explained hereunder in greater detail in relation to non-limiting exemplary embodiment of the system. Reference is first invited in figure 7 which illustrates improved system for flattening of cold rolled strips in accordance with the present invention. As illustrated in said figure such a system basically comprise of chassis (2) for supporting the various components having at its lower end the fixing brackets for rigidly supporting the chassis. The system include the pinch roll (3) housed within the pinched roll housing (4), screw down motors (5), working rolls (6). The front guard (7) is provided to avoid shifting of the system during use. Importantly, the system of the invention avoids the use of drive system comprising the usual motor gearbox and coupling means and instead provides thrust bearing arrangement for absorbing the thrust on the rollers. As clearly illustrated in figure 1, the thrust bearing arrangement is provided both for the upper rolls as well as for the lower rolls. As shown in figure 4 the modification at the non-drive end of the upper rolls comprise provision of the upper bearing block (15) in which the roll neck is assembled. Upper bush holder (16) holds the hard teflon bush (12) and stainless steel washer (13) are provided to assemble the roll neck with respect to said bearing block by means of a screw (6) and clamping bolt (14). Importantly, the contact pressure of the roll end at the hard teflon bush is controlled through the said adjusting screw (6) and a lock nut (5). Reference is now invited to fig. 5 which illustrate the modification for preventing axial shift of the rolls at drive side upper bearing block (8). The roll neck is adapted to pass through such upper bearing block as also shown in said figure. Similar to that described in relation to figure (4), the upper bush holder (9) holds the hard teflon bush (3) and hard stainless steel washer (4). Clamping bolt (7) is provided to hold the assembly to the main equipment. Adjusting screw (6) and lock (5) are provided to adjust the pressure over the roll face. All the features provided for the side of the assembly are same/similar to that of features used for the modification at the non-drive sides as discussed hereinbefore. Reference is now invited to figure 9 which illustrate the modification carried out for lower rolls at the non-drive side i.e. operator side and at the drive side i.e. non-operator side respectively. As shown in figure 6 in such modification the lower bearing block (10) constitute the part of the original equipment to which lower bush holder (11), teflon bush stainless steel washer are mounted. Adjusting screw and lock nuts (6 and 5) are provided to impart requisite pressure to the rolls. Substantially similar to that of the arrangement discussed above in relation to figure 6 the arrangement thrust bearing for the lower rolls at the drive side or the non-operator side is further represented in figure 7. Reference is invited to fig. 8 which illustrates the modified chassis used in the system of the invention. As shown in said figure the chassis is basically comprises of a supporting frame structure similar to that of the existing chassis having a top platform (TP) and downwardly extending leg portion (LP). In order to impart additional stability and rigidity to the chassis the same is provided with a base plate (BP) and stiffner means. Such stiffner means comprises bracket like members (ST) which are secured to said the leg portion through vertical plates (VP). Reference is finally invited in figure 9, which shows the modification in the leveller roll end adapted to accommodate the thrust bearing arrangement in the system of the invention As illustrated in said figure the leveller roll end is provided with a modified machined shape and configuration for fixing to the thrust bearing. . , It is thus possible by way of the present invention to provide for an improved equipment for handling strips in tension for flattening of cold rolled strip. It is possible by way of the system of the invention to avoid the use of motor and multi output gear box in driving the motor as used in conventional leveller thereby providing for a much simpler and cost effective equipment. The provision of side thrust bearing arrangement is directed to provide smooth and convenient use of the system in the flattening of cold rolled strips. The modification in the chassis which provides for its fixing to the ground is directed to import stability and rigidity to the system. In particular, by provision of the fixing of the equipment on firm foundation more rigidity is provided to the equipment to achieve better levelling. In the improved system the removal of the drive is achieved as because the strip is continuous and tension provided by the coiler and uncoiler. The system effectively takes care of side thrust exerted on the bush bearings by way of antifriction thrust bearing disclosed herein. It is thus possible by way of the improved system of the present invention to achieve a more convenient and effective flattening of cold rolled strips. WE CLAIM : An improved system for flattening of cold rolled strips comprising : working rolls comprising upper and lower working rolls (6) adapted to allow passage of the strip to be flattened therebetween ; screw down motors (5) operatively connected to screw down mechanism adapted to exert vertical force to the strip through said working rolls ; for guiding of the strip through there between said upper and lower working rolls(6); thrust bearing arrangement assembled with respect to said working rolls for preventing side thrust. An improved system for flattening of cold rolled strips as claimed in claim 1 wherein said for guiding the strips through said upper and lower working rolls comprise pinch roll (3) housed within a pinch roll housing(4). An improved system for flattening of cold rolled strips as claimed in anyone of claims 1 or 2 wherein said thrust bearing comprise mounting of said upper and lower rolls in respective thrust bearing arrangement. An improved system as claimed in claim 3 wherein said thrust bearing arrangement at the upper roll comprise modifications at the non-drive end and the drive end of the upper roll. An improved system as claimed in claim 4 wherein the modification at the non-drive end of the upper roll comprise the roll neck assembled in an upper bearing block(15); said roll neck assembled with respect to said upper bearing block by of adjustable screw and bolt including a bush holder(16) and a bush ; the contact between said roll and said bush adapted to be adjusted by the said screw and nut. An improved system as claimed in claim 5 wherein said bush holder holds (16) a hard teflon bush (12) a stainless steel washer(13). An improved system as claimed in anyone of claims 1 to 6 wherein said modification at the drive end of the upper rolls comprise a drive side upper bearing block adapted to allow passage of roll neck therethrough ; adjustable screw and bolt mechanism to hold said neck with respect to said bearing block including bush holder holding a bush and washer; said screw and bolt adapted to adjust the pressure over the roll face. An improved system as claimed in claim 7 wherein said holder holds a hard teflon bush and stainless steel washer. An improved system as claimed in anyone of claims 1 to 8 wherein said thrust bearing at the lower rolls comprise modifications at the non-drive side and also modifications at the drive side of said lower rolls. . A system as claimed in claim 9 wherein the modification at the non-drive side and the drive side end of the lower rolls comprise ; a bearing block adapted to assembly the neck portion of the lower roll; screw and bolt adapted to assemble said neck portion of the roll with respect to said bearing block including a bush holder accommodating a bush and washer the thrust there between said end face of the neck of said roll with respect to said bush adapted to be adjusted by of said screw and bolt. . An improved system as claimed in claim 10 wherein said bush holder hold a hard teflon bush and stainless steel washer. An improved system as claimed in anyone of claims 1 to 11 comprising a chassis(12) from supporting the different components. An improved system as claimed in anyone of claims 1 to 13 comprising front guard (13) to prevent shifting of assembly. An improved system as claimed in anyone of claims 1 to 13 adapted for fixing to the ground through said chassis. An improved system as claimed in anyone of claims 1 to 14 wherein said chassis comprises : a support comprise a top platform and plurality of vertically downwardly extending legs thereof; a base plate supporting said legs and from stiffening the leg support for said top platform. An improved system as claimed in claim 15 wherein said for stiffening comprising bracket (1) operatively connected to said base plate and said leg portions. An improved system as claimed in anyone of claims 1 to 16 wherein said roll end portions are adapted to be assembled with respect to said thrust bearing arrangements. An improved process for flattening of cold rolled strips using the system as claimed in anyone of claims 1 to 17. An improved system and method of flattening of cold rolled strips substantially as hereindescribed and illustrated with reference to the accompanying figures. An improved system for flattening of cold rolled strips without use of motor and multi output gearbox as that required in known conventional leveller comprising thrust bearing arrangement assembled with respect to the working rolls of said leveller for preventing side thrust. The system of the invention further avoids the requirement of mounting on-line or off-line of the leveller and instead provides for improved chassis for supporting the different components with said leveller adapted to be fixed to the ground through said chassis. The improved system thus provides for a firm foundation and rigidity and facilitate the improved flattening of strips. The system is simple to obtain and use and is also at the same time cost effective.

Documents:

00173-cal-2000-abstract.pdf

00173-cal-2000-claims.pdf

00173-cal-2000-correspondence.pdf

00173-cal-2000-description (complete).pdf

00173-cal-2000-drawings.pdf

00173-cal-2000-form 1.pdf

00173-cal-2000-form 18.pdf

00173-cal-2000-form 2.pdf

00173-cal-2000-form 3.pdf

00173-cal-2000-letter patent.pdf

00173-cal-2000-pa.pdf