The present invention relates to the manufacture of seamless pipe. More particularly this invention concerns a roll stand having tapered rolls for making such pipe.
A rolling stand or apparatus for making seamless pipe typically has a massive stationary frame on which are mounted two driven tapered rolls with frustoconical outer surfaces and two Diescher disks. The rolls flank a normally vertical travel plane that bisects the horizontally moving workpiece, and the Diescher disks are above—and below the workpiece. The tapered rolls are rotatable about respective axes that form opposite but complementary small acute angles with the workpiece, and the Diescher disks rotate about axes perpendicular to the travel plane. The raw tubular workpiece is pressed against a piercing rod or mandrel by the four rotating tools to longitudinally stretch and radially compress it into an exactly dimensioned seamless pipe.
As described in U.S. Pat. No. 6,546,772, the roll stand is formed two portal frames lying spaced apart in the workpiece-travel direction and connected to each other by a lower traverse and an upper traverse. The upper transverse is slidable in guides between the portal frames to facilitate insertion and removal of the rolls.
Changing the rolls in the known double tapered-roll apparatus with an upper and a lower frustoconical roll is a time-consuming and difficult operation. First, the upper traverse must be moved horizontally to the side in order then to be able to lift the frustoconical rolls one after the other out of the roll stand with a crane. The surrounding equipment does not permit a movement of both stand sides or portal frames, so that simultaneous replacement of both rolls is not possible. Instead, this always takes place consecutively, never at the same time.
It is therefore an object of the present invention to provide an improved tapered-roll stand for making seamless pipe.
Another object is the provision of such an improved tapered-roll stand for making seamless pipe that overcomes the above-given disadvantages, in particular that has a simplified design making a quick procedure for removing worn tapered rolls and replacing them with fresh rolls.
A tapered roll stand for making seamless pipe has according to the invention a stationary frame formed relative to a workpiece-travel direction with a pair of laterally and horizontally oppositely open windows. Respective cover doors carried on the frame are vertically shiftable between respective closed positions covering the respective windows and open positions offset therefrom and exposing the respective windows. A pair of tapered rolls are each shiftable horizontally through a respective one of the windows into a use position inside the frame, lying to a respective horizontal side of the direction, and rotatable about a respective axis forming an acute angle with the direction. A pair of Diescher disks are vertically engageable with a workpiece extending in the direction between the tapered rolls, and respective roll-positioning actuators carried on the doors are couplable with the tapered rolls in the use position for setting positions of the tapered rolls.
Thus according to the invention the tapered rolls lie next to one another horizontally in the roll stand, and are shiftable on a respective side of the roll stand through a mounting window. Roll adjusters or actuators are carried roll stand side cover doors that can be raised and lowered. To replace the rolls it is no longer necessary to release and displace an upper traverse, instead both tapered rolls can be replaced at the same time, namely drawn out of their respective windows orthogonally to the roll axis. After the opening of the roll stand sides by shifting the doors in opposite vertical directions, i.e. raising the one and lowering the other roll stand side closing cover by a hydraulic or pneumatic cylinders can be used, the unhindered insertion or removal of the tapered rolls is an easy job. The replacement of rolls thus no longer requires a very time-consuming displacement or lifting or pivoting the upper stand half, so that due to the much shorter roll replacement times achieved according to the invention the service time of the roll stand is also improved.
The rolls oriented horizontally next to one another according to the invention further renders possible large roll spreading angles, in turn is advantageous in terms of forming because it makes larger outside tube diameters possible. With the known roll arrangement one above the other, large spread angles (>20°) cannot be realized due to the increased installation height of the roll stand drive unavoidably associated therewith.
According to an advantageous embodiment of the invention, linear guides carrying moveable tapered roll replacement units, for example, replacement carts or moveable slides, extend horizontally orthogonally to the rolling axis or workpiece travel direction. They are each aligned with a respective one of the mounting windows of the tapered roll mounts. The automated simultaneous replacement of the two tapered rolls is further promoted in this way.
Another advantageous embodiment of the invention provides Diescher disk units arranged vertically in the roll stand, one above and one below. This also contributes to there being sufficient space for the simultaneous roll change in the region of the mill floor on the right and on the left of the workpiece travel direction or next to the roll stand.
The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:
As seen in
Upper and lower assemblies 14a and 14b carry respective Diescher disks 15a and 15b (see
Number | Date | Country | Kind |
---|---|---|---|
10 2011 120 783 | Dec 2011 | DE | national |
Number | Name | Date | Kind |
---|---|---|---|
3566653 | Unrath | Mar 1971 | A |
4052876 | Rotter | Oct 1977 | A |
4976127 | Rohde et al. | Dec 1990 | A |
5590557 | Keller et al. | Jan 1997 | A |
5875671 | Hauck | Mar 1999 | A |
6266987 | Goto et al. | Jul 2001 | B1 |
6546772 | Hoffgen et al. | Apr 2003 | B2 |
20120279270 | Yabuta et al. | Nov 2012 | A1 |
Number | Date | Country |
---|---|---|
201841156 | May 2011 | CN |
201978942 | Sep 2011 | CN |
202045129 | Nov 2011 | CN |
Number | Date | Country | |
---|---|---|---|
20130145808 A1 | Jun 2013 | US |