Patent Publication Number: US-6209378-B1

Title: Adjustable monitoring guide

Description:
RELATED APPLICATIONS 
     This application claims priority from Provisional Patent Application Ser. No. 60/132,242 filed May 3, 1999. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     This invention relates to roller guides of the type employed in rolling mills to guide rod and bar products into roll passes. 
     2. Description of the Prior Art 
     In the rolling of steel rods and bars, significant operational benefits can be realized by employing so-called “reducing-sizing mills” (“RSM”) of the type disclosed in U.S. Pat. No. 5,325,697 issued Jul. 5, 1994 to Shore et al., the description of which is herein incorporated by reference in its entirety. Advantages of rolling with such mills include improved dimensional control of the finished product, higher mill utilization and increased free sizing capability. 
     FIG. 1 illustrates a typical pass progression of the reducing-sizing process, which begins with a leading oval  10  followed by three round passes,  12 ,  14  and  16 . Relatively small changes in the finished round bar or rod can be made by changing the roll partings on the last three round passes. Alternatively, the feed section, which is typically round, can be changed slightly, but this entails adjusting upstream mill equipment, resulting in a non round feed section, which can impose other process limitations. 
     There has been a reluctance on the part of those skilled in the art to undertake any parting changes to the oval pass  10 , owing to problems associated with adjusting downstream roller entry guides to exactly match the resulting modified oval. Previous technology roller guides do not have the capability to be precisely adjusted whilst located on the mill and an offline alignment station is usually used for this, which obviously requires removal of the guide from the mill and therefore a mill stoppage. 
     Feeding an oversized section through a roller entry guide is not desirable since this drastically reduces the life of the bearings within the guide rollers and can lead to some further processing problems. If the oval section is adjusted to be smaller than the guide setting, a severe oscillation of the rolled product manifests within the guide, causing severe processing problems and poor quality finished product. 
     An objective of the present invention is to provide a roller guide assembly which can be precisely adjusted on line to accommodate different sized process sections, thus making it possible for example to change the parting of the oval pass  10 , which in turn beneficially increases the free sizing capability of the mill. 
     Additional objectives and advantages will become evident as the description proceeds with reference to the accompanying drawings, wherein: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagrammatic illustration of a typical pass progression in a reducing-sizing process; 
     FIG. 2 is a partially sectioned top plan view of a roller guide assembly in accordance with the present invention; 
     FIG. 3 is a partially sectioned side view of the roller guide assembly; 
     FIG. 4 is a partially sectioned end view of the roller guide assembly as viewed from right to left in FIG. 3; 
     FIG. 5 a  diagrammatically illustrates the forces acting on one of the guide arms; and 
     FIG. 5 b  is a graph depicting the relationship between the measured force acting on each roller holder and its deflection from an initial reference setting. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring initially to FIGS. 2-4, a roller guide assembly in accordance with the present invention is generally indicated at  18 . The guide assembly includes a rigid housing structure commonly referred to as a “guide box” having a base  20 , with integral laterally spaced side members  22 , and a nose piece  24 . A pair of roller holders  26  extends lengthwise of the housing structure on opposite sides of the intended direction of travel “T” of the workpiece, in this case an oval process section received from the oval pass  10  for delivery into the next successive round pass  12 . 
     Guide rollers  28  are rotatably carried at the forward ends of the roller holders  26 . The guide rollers define a gap therebetween, and are configured to engage and guide the oval process section so that it is correctly presented to the round pass, with the elongate axis “A” of the oval (shown in FIG. 1) normal to the axes of the rolls of the round pass  12 . 
     The housing structure further includes vertical pivots  30  on which the roller holders  26  are mounted for movement about axes extending generally parallel to the rotational axes of the guide rollers  28 . 
     Compression springs  32  are located in bores in the roller holders  26 . The springs abut the side members  22  of the housing structure and are captured in their respective bores by cover plates  34  secured to the roller holders. The springs  32  are loaded in compression and as such, exert yieldable forces “F” (see Figure Sa) on the roller holders urging the roller holders to rotate in opposite directions about the pivots  30 , as depicted diagrammatically by the arrows in FIG.  2 . 
     The spring-induced rotation of the roller holders is resisted by stops comprising adjusting screws  36  positioned to be contacted by load sensitive sensors  38  carried on rearward extensions of the roller holders. 
     As can be seen in FIG. 4, the adjusting screws  36  are threaded into right and left hand threaded sections of the side members  22  of the housing structure. The square ends  42  of the adjusting screws slide axially within the square bore  40  of a gear  44  meshing with a gear  46  on a drive shaft  48  having two drive points  48   a ,  48   b . The drive point  48   a  is for manual adjustment, generally used for off-line setting of the guide. The other point  48   b  mates with the output shaft  50  of a 90° gear box  52  powered either manually, or by a motor (not shown) which may be controlled remotely. 
     As shown in FIG. 5 a , the force F exerted by the spring  32  is opposed by force “L”, with the sensors  38  serving to measure the magnitude of the force F. 
     Various modes of operation are possible after initial set-up. 
     1. Position Control Mode 
     FIG. 5 b  shows that when the guide is adjusted to its desired setting “G 1 ”, the output of each sensor is recorded as “F 1 ”. The guide is then deflected to a different known setting “G 2 ” by means of gauge bar or other means of controlled deflection (not shown), and the new sensor output “F 2 ” recorded. This can be repeated for several other setting if desired for improved accuracy. However, two points are usually sufficient to describe the relationship between guide setting and sensor output which is generally linear. 
     Knowing the relationship between guide setting and sensor output enables the guide to be adjusted to a pre-determined sensor setting “F x ” which corresponds to the desired parting between the guide roller “G x ”. Hence the guide can be accurately positioned without being removed from the mill. 
     When changes are required to the process oval, the guide can be remotely adjusted in order to re-position the guide rollers to the desired oval height, leading to an increase in the free sizing range capability of the reducing and sizing operation. 
     2. Sensor Output Control Mode 
     For this mode it is assumed that the spring element used within the guide has negligible variation when the guide parting is adjusted by small amounts. 
     The guide is set as detailed above and once the rollers are at the correct setting for the section being rolled, the output of the sensor (or sensors) is recorded. 
     The guide is then installed on the mill and when the stock enters the guide, the sensor output is again monitored and recorded. If the mill is set correctly, the sensor output during rolling should be very close to that of the initial setup. If not, then the mill roll gap can be adjusted to change the height of the leading oval until this condition is met. 
     When adjustments are required to the oval pass, the guide can be adjusted using the remotely operable adjustment apparatus as detailed above, such that the parting between the guide rollers is approximately the magnitude required by the new set up. When the first bar of the new size enters the guide, the sensor output is monitored and compared with the initial setup value. If necessary the guide can be adjusted accordingly until the correct output is achieved. Ideally this is undertaken in automatic closed loop control, but may also be controlled manually. 
     This mode of operation ensures that the guides are always set to match the dimensions of the process oval. When the process oval is changed, the guide can be made to adapt accordingly, therefore leading to an increase in the free sizing range capability of the reducing and sizing operation. 
     This mode also enable the guide to be set to eliminate over-loading or oscillating stock as well as enabling the guide to be remotely adjusted in accordance with temperature and yield strength changes associated with different grade products. 
     All of the above concepts can be applied to the rolling of shapes and flat product as well as rounds. 
     In light of the foregoing, it will now be appreciated by those skilled in the art that various changes and modifications may be made to the embodiment herein chosen for purposes of disclosure without departing from the spirit and scope of the invention as defined by the appended claims. For example, although compression springs  32  have been disclosed, other force exerting components could be substituted, including disc springs, fluid actuated devices, elastomers, etc. The sensors may be other than load sensitive, including for example those sensitive to strain, pressure deflection, etc. Also, although two sensors are shown, one for each roller holder, an acceptable alternative would be to employ only one sensor on one of the roller holders.