Abstract:
A modular rolling mill includes a plurality of rolling units arranged along a mill pass line, each rolling unit being independently driven by a dedicated motor and drive train; and clutches for selectively coupling and de-coupling the drive trains of successive pairs of rolling units.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit, under 35 U.S.C. §119(e), of U.S. Provisional Application Ser. No. 61/705,233 filed on 25 Sep. 2012, the contents and substance of which are herein incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    Embodiments of the present invention relate generally to rolling mills, and are concerned in particular with the provision of an improved modular rolling mill for finish rolling long products such as round rods and bars as well as shaped products. 
         [0004]    2. Description of Related Art 
         [0005]    As disclosed, for example, in U.S. Pat. Nos. 4,537,055 (Woodrow et al.) and 5,152,165 (Shore et al.), known block type finishing mills typically comprise multiple mechanically coupled roll stands driven by a common motor. 
         [0006]    It is also known, as disclosed for example in U.S. Pat. Nos. 5,595,083 (Shore) and 7,191,629 (Shore et al.), to subdivide the finishing mill into multiple mechanically coupled rolling units, each of which includes two pairs of work rolls. 
         [0007]    In these finishing mills, because the roll stands or rolling units are permanently coupled mechanically, the inertia of the entire mill serves to dampen impact speed drops caused by the entry of a product front end into the successive roll passes. On the negative side, however, is the relatively high cost of such finishing mills, due in large part to the complex and costly gear trains required to achieve mechanical coupling of the roll stands or rolling units, and the large and costly motors employed to drive the mills. 
       SUMMARY 
       [0008]    Broadly stated, embodiments of the present invention are directed to the provision of a modular finishing mill comprising a plurality of rolling units arranged along a mill pass line, with each rolling unit being independently driven by a dedicated motor and drive train, and with clutches for selectively and temporarily coupling and de-coupling the drive trains of successive pairs of the rolling units. 
         [0009]    In exemplary embodiments, the rolling units include pairs of work rolls carried on roll shafts, with the drive trains comprising gear sets mechanically coupling the roll shafts to drive shafts powered by the motors. 
         [0010]    The drive shafts may all be driven at substantially the same speed, with the gear sets being configured and arranged to effect stepped increases in the speed of the roll shafts of successive roll pairs. 
         [0011]    The clutches may be interposed between the drive shafts of successive rolling units, and may comprise electro magnetic or ferro fluid clutches. 
         [0012]    In an exemplary method of rolling a product of finite length with a modular finishing mill in accordance with the present invention, successive pairs of the rolling units are coupled together prior to the arrival of a product front end at the first rolling unit. The coupling of the rolling units is maintained until the product front end has cleared the last rolling unit, at which time the rolling units are de-coupled and maintained in a de-coupled state while rolling the remaining product length. 
         [0013]    These and other features and advantages of the present invention will become more apparent upon reading the following detailed description in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a plan view of a modular finishing mill in accordance with an exemplary embodiment of the present invention; 
           [0015]      FIG. 2  is a sectional view taken along line  2 - 2  of  FIG. 1 ; and 
           [0016]      FIG. 3  is an enlarged plan view of a portion of the modular finishing mill shown in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    The components described herein as making up the various embodiments are intended to be illustrative and not restrictive. Many suitable components that would perform the same or a similar function as well as the materials described herein are intended to be embraced within the scope of embodiments of the present invention. 
         [0018]    Referring now to the figures, wherein like reference numerals represent like parts throughout the views, an illustrative embodiment of a modular finishing mill in accordance with the present invention is generally depicted at  10 . The mill comprises a plurality of rolling units  12  arranged in succession along a mill pass line. Each rolling unit  12  is independently driven by a dedicated motor  14  and drive train  16 . Each rolling unit  12  may employ two pairs of work rolls indicated typically at  18 . As can be best seen in  FIG. 2 , the work rolls are carried on roll shafts  20  mechanically coupled by gear sets  22 ,  24  to a drive shaft  26  comprising part of the drive train  16 . The drive shafts of adjacent rolling units are parallel. 
         [0019]    As depicted in  FIG. 3 , axially aligned first and second stub shafts  28 ,  30  are provided between adjacent drive shafts  16 . Each of the stub shafts  28 ,  30  carries a gear  32  in meshed relationship with a gear  34  on a respective one of the adjacent drive shafts  16 . The stub shafts  28 ,  30  are interconnected by clutches  36 , which may comprise electro magnetic or ferro fluid clutches. 
         [0020]    When the clutches  36  are disengaged, the stub shafts  28 ,  30  are disconnected and free to rotate independently of each other, resulting in a de-coupling of the adjacent rolling units  12 . Engagement of the clutches  36  may provide up to  100 % lock up of the stub shafts  28 ,  30 , with the engaged gear sets  32 ,  34  serving to mechanically couple the adjacent rolling units  12 . 
         [0021]    When rolling a product of finite length with the above described illustrative embodiment of a finishing mill in accordance with the present invention, prior to the arrival of a product front end at the first rolling unit  12 , the clutches  36  may be engaged to achieve a coupling of successive rolling units. Coupling may be maintained while the product front end negotiates each of the roll passes defined by the successive pairs of work rolls  18 . After the product front end has cleared the roll pass of the last rolling unit, the clutches  36  may be disengaged, allowing the rolling units  12  to operate independently while rolling the remaining length of the product. 
         [0022]    When the successive rolling units  12  are coupled together, the inertia of the entire mill is available to dampen any impact speed drop caused by the entry of a product front end into the roll passes of a successive roll pairs. 
         [0023]    While exemplary embodiments of the present invention have been disclosed, modifications, additions and deletions can be made without departing from the spirit and scope of the invention and its equivalents, as set forth in the following claims.