Modular finishing mill

1. A modular rolling mill, comprising:

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, wherein when the clutches disengage, the rolling units are allowed to operate independently while rolling a remaining length of a product through the mill pass line.

2. The modular rolling mill of claim 1 wherein said rolling units employ pairs of work rolls carried on roll shafts, and wherein said drive trains comprise gear sets mechanically coupling said rolls shafts to drive shafts powered by said motors.

3. The modular rolling mill of claim 2 wherein said drive shafts are driven at substantially the same speed, and wherein said gear sets are configured and arranged to effect stepped increases in the speed of the roll shafts of successive rolling units.

4. The modular rolling mill of claim 3 wherein said clutches are interposed between the drive shafts of successive rolling units.

5. The modular rolling mill of claim 4 wherein said clutches comprise either electromagnetic clutches or ferro fluid clutches.

6. The modular rolling mill of claim 1 wherein said drive trains include drive shafts, with the drive shafts of adjacent rolling units being parallel.

7. The modular rolling mill of claim 6 further comprising axially aligned and independently rotatable first and second stub shafts arranged between and parallel to the drive shafts of adjacent rolling units, said first stub shaft being mechanically coupled to the drive shaft of one of said adjacent rolling units, and said second drive shaft being mechanically coupled to the drive shaft of the other of said adjacent rolling units, with said clutches being arranged to couple and de-couple said stub shafts.

8. A method of rolling a product of finite length through a modular rolling mill comprising a plurality of separately driven rolling units arranged in succession along a mill pass line, said method comprising:

temporarily coupling successive pairs of said rolling units prior to the arrival of a front end of said product at the first of said rolling units;

maintaining the coupling of said rolling units until the product front end has cleared the last of said rolling units; and then

de-coupling said rolling units for continued operation in a de-coupled state while rolling a remaining length of said product.

9. The method of claim 8 wherein said rolling units employ pairs of work rolls carried on roll shafts, wherein gear sets mechanically couple the roll shafts to drive shafts powered by motors, and wherein the successive pairs of rolling units are coupled and de-coupled by clutches interposed between said drive shafts.

10. A method of rolling a product of finite length through a modular rolling mill comprising a succession of separately driven rolling units, wherein a speed drop is occasioned by the arrival of a front end of the product at each rolling unit, said method comprising:

temporarily maintaining successive pairs of said rolling units in a coupled state while front end of said product passes through said rolling mill; and

after the front end of said product has cleared the last rolling unit, de-coupling and maintaining said rolling units in a de-coupled state during the rolling of remainder of said product length through said rolling mill.