Patent Description:
Levelers, such as hot levelers, are commonly used in metal sheet and plate mills, namely hot rolling mills for producing metal sheets or plates. <FIG> illustrates a typical leveler <NUM> from the operator side. As shown in <FIG>, the leveler usually includes moveable upper work rolls <NUM> and stationary lower work rolls <NUM>. The metal sheet or plate enters the leveler from entry side <NUM> of the leveler, passes between the upper and lower working rolls, and then leaves the leveler through exit side <NUM>. The rolling and cooling processes of the leveler reduce remaining flatness errors and residual stresses of the metal sheets or plates passing therethrough. However, as a result of passing metal sheets or plates through the rollers, under substantial compressive forces on the metal sheets or plates, particles tend to collect on the work rolls working the metal sheets or plates, which could cause gouges, pits, and scratches of the sheet and degradation in the quality of subsequently leveled plates. Thus, the polishing and cleaning of the work rolls is crucial for the effectiveness and quality of the metal sheets or plates passing through the levelers.

Conventionally, a leveler is polished by bracing the leveler in an open position, in which top portion <NUM> of the leveler is raised (e.g., with a roll nest support car). An operator would physically crawl into the open leveler and use a hand grinder power tool to grind-polish the work rolls. This process is potentially dangerous and inefficient, as operators could possibly be injured while polishing the work rolls. Likewise, the extent to which the work rolls are consistently and qualitatively cleaned varies from operator to operator, or upon the mechanical condition of the grinding equipment, as well as whether or not a region on the work rolls is completely accessible to the operator attempting to polish the work rolls. Uniformity in the polishing operation can vary not only relative to the accessibility of the work roll region, it can vary as a function of the amount of time and pressure invested by the operator. The lack of uniformity can affect the resulting condition of the work rolls, and, in turn, the quality of the leveled metal sheet or plate. More automated approaches have been utilized. One such technique, disclosed in Chinese Pat. No. <CIT> calls for the use of a concave-shaped steel -bristle brush for cleaning a work roll. Alternatively, Japanese Pat. No. <CIT> discloses the use of a cleaning member that includes an inflatable air bladder that reciprocates along the length of a work roll, while the work rolls are rotated, to clean them. <CIT> discloses a metal leveller with roll grinding components to allow grinding of the rolls during use. <CIT> discloses an apparatus for polishing support rollers in a metal leveller after working rolls are removed. <CIT> discloses an apparatus for polishing rollers with interchangeable polishing material. <CIT> discloses a scraper device for continuously cleaning work rolls of a metal leveller. <CIT> discloses an apparatus for grinding leveler rolls which is adapted to be installed from the housing on the operation side only when required and removed from the housing upon the termination of grinding. The present invention has as its objectives, the goal of efficiently, effectively and safely cleaning the work rolls to ensure the quality of the metal sheets or plates being processed by the leveler itself. These and other objectives and advantages will become apparent in view of the following disclosure, including the drawings and claims.

A selection of optional features is set out in the dependent claims.

The following drawings illustrate by way of example and not limitation. For the sake of brevity and clarity, every feature of a given structure is not always labeled in every figure in which that structure appears. Identical reference numbers do not necessarily indicate an identical structure. Rather, the same reference number may be used to indicate a similar feature or a feature with similar functionality, as may non-identical reference numbers.

Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to these embodiments.

Generally speaking, various embodiments of the present invention provide for apparatuses and methods for safely and efficiently polishing the work rolls of a metal sheet or plate leveler for example, hot leveler <NUM> as shown in <FIG>. The metal may be any metal, including but not limited to steel, aluminum or bronze. Leveler <NUM> is made up of top portion <NUM>, which can be raised and lowered, and bottom portion <NUM>, which is typically stationary.

Apparatus <NUM>, as shown in <FIG>, may include polishing unit <NUM> and stationary table support <NUM>. Table support <NUM> may be positioned in front of leveler <NUM>,) where polishing unit <NUM> may be moved and inserted (and/or removed) from a position between the opposing series of work rolls <NUM>, <NUM> (e.g., upper work rolls <NUM> and lower work rolls <NUM>) of leveler <NUM>, from the operator side (non-driven side) of the leveler. Polishing unit <NUM> may include multiple polishers <NUM> on its top and bottom surfaces, and thus is capable of polishing a plurality of work rolls <NUM> of leveler <NUM> during the rotation of work rolls <NUM>, while each of polishers <NUM> engages and polishes at least the majority of the operable length of a corresponding work roll of the leveler. Further, the polishing unit may include one or more internal expandable elements, such as air bags <NUM>, between upper and lower platforms <NUM>, <NUM> of polishing unit <NUM> (as shown in <FIG>), to allow polishing unit <NUM> to be expanded within leveler <NUM>, thereby causing polishers <NUM> (e.g., the abrasive material within the pans) to contact and polish the rotating work rolls <NUM>, <NUM>. In some embodiments, the polishing unit simultaneously contacts and polishes, or just polishes, all of the upper and/or lower work rolls during the polishing process, as shown in <FIG>. After the polishing process, the expandable element may be retracted, to reorient platform <NUM> proximate to platform <NUM>, to enable polishing unit <NUM> and, if desired, apparatus <NUM> in its entirety, to be removed from proximity with the leveler.

<FIG> illustrates polishing apparatus <NUM> in accordance with various other embodiments of the present invention. Apparatus <NUM> includes apparatus table <NUM> with support leg <NUM>. Stationary apparatus table <NUM> balances and supports polishing unit <NUM> movably positioned thereon, to enable polishing unit <NUM> to reciprocate into and out of leveler <NUM> while leveler <NUM> is in its open position. A user may operate and control the movement of polishing unit <NUM> relative to table <NUM>, optionally by motor <NUM> (such as an air motor), with its controls and valves <NUM>(a) thereby moving polishing unit <NUM> into and out of a leveler <NUM>. Further, polishing unit <NUM> may include one or more polishers <NUM>, on each of its top and bottom platforms <NUM>, <NUM>. Each polisher <NUM> is shaped and sized to align with, engage and receive corresponding work roll <NUM>, <NUM> of leveler <NUM>. As shown in <FIG>, polishers <NUM> comprise substantially rigid concave pans <NUM>(a), each supporting an abrasive surface or abrasive lining <NUM>(b), or a combination of a firm rubber backing <NUM>(b) and an abrasive paper <NUM>(c), as shown in <FIG>. As such, during the polishing process, multiple work rolls of the leveler may simultaneously be polished by abrasive surfaces.

<FIG> shows a side view of polishing unit <NUM>, to illustrate the structures and components of this embodiment in more detail. Specifically, platforms <NUM> and <NUM> are shown in their retracted orientation position in <FIG>. In this embodiment, upper polishers <NUM> on platform <NUM> are configured to be extended away from the lower polishers <NUM> on lower platform <NUM>. The juxtapositioning of the two platforms making up polishing unit <NUM> enables polishing unit <NUM> to be inserted between the upper and lower work rolls within leveler <NUM>; once the series of upper work rolls <NUM> in movable leveler top portion <NUM> have been retracted away from the stationary series of leveler lower work rolls <NUM> in stationary leveler bottom <NUM>, as the leveler assumes its open position shown in <FIG>.

Also shown in <FIG> are air bags <NUM> for extending platform <NUM> away from platform <NUM>, upon activation of the air bags, such as also by air motor <NUM> and air motor control <NUM>(a), shown in <FIG>, or by a separate air motor. The shape of the concave pans making up polishers <NUM> is shown in <FIG>, together with the abrasive linings <NUM>(a) in each such pan. A close-up of the polisher structure is shown in <FIG>. As shown in phantom in <FIG>, as an alternative to air motor <NUM>, an electric motor <NUM>, together with motor control <NUM>(a), can be utilized to extend upper platform <NUM> apart from lower platform <NUM> to engage work rolls <NUM>, <NUM> with respective polishers, when the work rolls are in their open position, through electric motor <NUM> and the rotation of motor gearing <NUM>, also shown in phantom. Platform lock lever <NUM> is also shown in <FIG>, together with polishing unit <NUM> locating lock pins <NUM> - which enable the alignment of the polishers <NUM> with respective ones of work rolls <NUM>, <NUM>, through cooperation of pins <NUM> with apertures in top portion <NUM> of leveler <NUM>. As shown in <FIG> and <FIG>, locating lock pins <NUM> specifically cooperate with aligned apertures in leveler top <NUM> to maintain the polishers in alignment with their respective work rolls, both immediately prior to and during the polishing operation.

As shown in <FIG>, polishing unit <NUM> includes upper platform <NUM> and lower platform <NUM>, where polishers <NUM> are positioned on the top surface of upper platform <NUM> and on the bottom surface of lower platform <NUM>. In the illustrated embodiment, upper platform <NUM> includes five concave polishers, and lower platform <NUM> includes six concave polishers, such that each polisher <NUM> corresponds to one of the eleven work rolls <NUM>, <NUM> of leveler <NUM> from <FIG>. Polishing unit <NUM> may also include one or more expandable elements <NUM> positioned between upper portion <NUM> and lower portion <NUM>. Expansion and retraction may be orchestrated by expandable air bag <NUM>, by hydraulic or pneumatic pistons, or by electric motor <NUM>, or the like. When apparatus <NUM> is in use, expandable element <NUM> causes polishers <NUM> to contact and polish rotating work rolls <NUM>, <NUM>. When apparatus <NUM> is not in use, it is desirable to retract expandable element <NUM>, so as to bring upper platform <NUM> and lower platform <NUM> closer together. Polishing unit <NUM> may include rollers and levers <NUM> to hold the upper and lower portions together when apparatus <NUM> is not in use.

<FIG> illustrate polishing unit <NUM> inserted in leveler <NUM>. Polishing unit <NUM> is inserted from the operator side of leveler <NUM> (e.g., towards the longitudinal direction of the work rolls). To ensure that polishing unit <NUM> is securely positioned within leveler <NUM>, especially during the polishing process, locating and locking pins <NUM> are utilized to locate and lock polishing unit <NUM> into level top <NUM> of frame <NUM> of the leveler, with the respective polishers <NUM> and work rolls <NUM>, <NUM> aligned for engagement and polishing. Entry and exit aprons <NUM> are placed on the entry and exit sides of leveler <NUM>, to allow for even elevation for insertion of polishing unit <NUM>. As shown in <FIG>, before the polishing process, expandable elements <NUM> are in their contracted state (e.g., not inflated), and upper platform <NUM> and lower platform <NUM> are locked together. In the illustrated embodiment, eleven polishers <NUM> are positioned proximate to each of the respective eleven work rolls <NUM>, <NUM> in leveler <NUM>. As shown in <FIG>, during the polishing process, expandable elements <NUM> may be extended (e.g., inflated) and adjusted. As such, the polishers in polishing unit <NUM> are extended to engage and contact the upper and/or lower work rolls of leveler <NUM>, and thus polishers <NUM> can polish the work rolls when the work rolls commence rotation. After the polishing process, expandable elements <NUM> may be retracted and polishing unit <NUM> may then be removed from the leveler by itself, or as part of the removal of overall apparatus <NUM>.

<FIG> displays the three primary layers of an embodiment of the present polishers, such as polishers <NUM>, namely concave pan <NUM>(a), resilient liner backing <NUM>(b), and abrasive material layer <NUM>(c).

In an alternative embodiment of the invention, as shown in <FIG>, platforms <NUM> and <NUM> are integrated into one unitary platform <NUM>, in which the upper and lower polishers <NUM> do not extend and retract from one another. In this embodiment, platform <NUM> is spring loaded relative to polishing unit <NUM> at spring coils <NUM>. Engagement of polishers <NUM> with work rolls <NUM>, <NUM> is accommodated by lowering leveler top <NUM> after the polisher unit has been inserted into the open leveler. In this embodiment, upper work rolls <NUM> in leveler top <NUM> engage and press upper polishers <NUM> on the top of platform <NUM>, and, in turn, lower polishers <NUM> on the bottom of platform <NUM> into aligned engaged contact with lower work rolls <NUM> in leveler bottom <NUM>. In this embodiment, the abrasive material <NUM>(c), or resilient backing <NUM> (b) within the substantially rigid tray <NUM>(a) of polisher <NUM> are thicker or otherwise more resilient, to accommodate the force which leveler top translates downwardly, to provide a tolerable range of polisher-on-work-roll pressures.

Claim 1:
An apparatus (<NUM>) for polishing the work rolls (<NUM>, <NUM>) of a metal leveler, (<NUM>) each said work roll (<NUM>, <NUM>) having a work roll circumference and a work roll length, the leveler (<NUM>) having a frame (<NUM>), a series of upper work rolls (<NUM>) and a series of lower work rolls (<NUM>), said apparatus (<NUM>) comprising:
- one or more polishing units (<NUM>) sized, shaped and configured to be removably inserted between the series of upper work rolls (<NUM>) and the series of lower work rolls (<NUM>) of the leveler (<NUM>) at a location between the series of upper work rolls (<NUM>) and the series of lower work rolls (<NUM>), said polishing unit (<NUM>) comprising at least one polisher (<NUM>) configured for engaging and polishing at least one of said series of upper and lower work rolls (<NUM>, <NUM>) of the leveler (<NUM>) during the rotation of said work roll,
- said at least one polisher (<NUM>) including a substantially rigid concave pan (<NUM>(a)) having an abrasive material (<NUM>(c)) positioned therewithin for exposure of said abrasive material (<NUM>(c)) to said respective work roll upon engagement of said polisher (<NUM>) with said respective work roll and upon rotation of said work roll by said leveler within said substantially rigid concave pan (<NUM>(a));
the apparatus (<NUM>) being characterized in that said at least one polisher (<NUM>) is configured to engage and polish at least the substantial length of a corresponding one of said work rolls (<NUM>, <NUM>) of the leveler (<NUM>) as said work roll is rotated, without repositioning said polisher (<NUM>) along the longitudinal axis of said work roll.