Combined drive for a four-or-six-high rolling stand and an operating method for the same
A roll stand has upper and lower rotatable working rolls defining a nip that pinches a workpiece strip and upper and lower vertically spaced rotatable backing rolls vertically flanking and engaging the working rolls. A drive includes a motor, upper and lower backing-roll outputs drivable by the motor, and upper and lower working-roll outputs also drivable by the motor. Respective upper and lower backing-roll and working-roll releasable connections are provided between the outputs and the respective rolls. When the working rolls are of large diameter, the backing-roll connections are released to disconnect the backing rolls from the drive and the working-roll connections are engaged to connect the working rolls to the drive and, when the working rolls are of small diameter, the working-roll connections are released to disconnect the working rolls from the drive and the backing-roll connections are engaged to connect the backing rolls to the drive.
1. A method of operating a roll stand comprising:
upper and lower vertically spaced rotatable outer backing rolls;
a pair of small-diameter working rolls;
a pair of large-diameter working rolls, each working-roll pair being fittable between the backing rolls;
a drive including
a motor,
upper and lower backing-roll outputs drivable by the motor, and
upper and lower working-roll outputs also drivable by the motor;
respective upper and lower backing-roll releasable connections between the upper and lower backing rolls and the upper and lower backing-roll outputs; and
upper and lower working-roll releasable connections connected to the upper and lower working roll outputs and connectable only to the large-diameter working rolls,
the method comprising the steps of alternatively:
fitting only the large-diameter working rolls between the backing rolls, disconnecting the backing rolls from the drive, and connecting the large-diameter working rolls via the respective connections to the drive; and
fitting the small-diameter working rolls between the backing rolls, disconnecting the small-diameter working rolls from the drive, and connecting only the backing rolls via the respective connections to the drive.
2. The roll-stand operating method defined in claim 1 wherein the stand further comprises:
inner backing rolls between the outer backing rolls and the respective working rolls, the drive having upper and lower inner backing-roll outputs drivable by the motor; and
respective upper and lower inner backing-roll releasable connections between the upper and lower inner backing-roll outputs and the upper and lower inner backing rolls,
the method further comprising the step of
only connecting the inner backing rolls via the respective releasable connections to the drive when the working rolls are disconnected from the drive.