Metal deforming – By use of roller or roller-like tool-element – Included in roller-cluster
Reexamination Certificate
2000-06-27
2001-08-21
Tolan, Ed (Department: 3725)
Metal deforming
By use of roller or roller-like tool-element
Included in roller-cluster
C072S235000, C072S237000
Reexamination Certificate
active
06276181
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a reducing mill disposed at the rear of a plant for manufacture of electro-resistance-welded steel tubes wherein a narrow and long successive steel plate (a strip) is gradually formed into a cylindrical shape, seam-welded, and then, reduced with its diameter by the reducing mill.
2. Related Art
A previous reducing mill having three rolls (three-roll-type reducing mill) comprised a stand supporting three rolls exclusive to each product size. If the rolls have worn away, the stand supporting the rolls is replaced with another stand supporting new three rolls. The worn rolls are ground and the stand having the rolls is used for diametrically larger products.
Later, the three-roll-type reducing mill has been improved so that its stand is provided with mechanisms for adjusting the position of the roll to mill a formed electro-resistance-welded tube into various sizes, as disclosed in an earlier application (Japanese Patent Application Laid-Open No. 9-262620) filed by the present applicant.
For the purpose of prevention of an irregularity or a flaw on an outer surface of a finished tube caused by positional difference between adjacent rolls in a radial direction of the tube, it is important for adjustment of a caliber formed by the three forming rolls of the three-roll-type reducing mill corresponding to a reduced diameter of a steel tube that each of two positionally-adjustable forming rolls is moved along a tangent to a curve of a positionally-fixed forming roll adjacent thereto for abutting against an objective tube at each of opposite ends of the positionally-fixed forming roll, in other words, along a direction at a 30° angle from a radial line of the positionally-fixed forming roll across the center of the objective tube.
This reducing mill comprises three rotary shafts; one is a drive shaft for one positionally-fixed main forming roll, and the other two are follower shafts for respective positionally-adjustable follower forming rolls which are driven by the drive shaft through respective bevel gears. Each rotary shaft is disposed in parallel to a shaft serving as an axis of a roll (a roll-axis shaft) on which each roll is fixed and drivingly connected with the roll-axis shaft through gears, so that the roll-axis shaft can be axially moved within the backlash between the gears. Also, the roll-axis shaft can be moved in perpendicular to its axis (radially) by sliding means. A movement of each of the follower forming rolls along a tangent to the curve of the main forming roll for abutting against an objective tube at each of the opposite ends of the main forming roll results from the two axial and radial movements of the roll-axis shaft.
However, since the axial movement of the roll-axis shaft and the radial movement thereof are independent of each other, each of the follower forming rolls, actually, cannot move straightly along the above-mentioned tangent. It is difficult to adjust the position of each of the follower forming rolls along the tangent exactly and for a short time by two operations for different movements of the roll-axis shaft of the follower forming roll. Furthermore, a proper positional adjustment of the follower forming rolls for the moment cannot be made during the processing of the reducing mill under inspection of finished products, even if any problem is found on the product finished by the reducing mill. It is only possible that a stand structure supporting the three forming rolls is adjusted with its two follower forming rolls in their positions before its incorporation into the plant for manufacture of electro-resistance-welded steel tubes or while the reducing mill or the entire plant is shut down in power for required adjustment thereof.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a three-roll-type reducing mill including three forming rolls disposed at regular intervals so as to arrange their axes in an equilateral triangle shape and brought into contact with an outer periphery of an electro-resistance-welded steel tube so as to mill the tube into round while reducing the diameter thereof, wherein one of the three forming rolls is a main forming roll fixed in position, the other two forming rolls are follower forming rolls drivingly following the main forming roll, and both of the follower forming rolls can be moved simultaneously with each other and symmetrically with respect to a center of the main forming roll along respective tangents to a curve of the main forming roll for abutting against the electro-resistance-welded steel tube at two opposite ends of the main forming roll. Thus, positions of the follower forming rolls can be changed while transmitting rotation driving force from the main forming roll to the follower forming rolls and the diametrical reduction of the steel tube can be adjusted without generating an irregularity or a flaw in an outside shape of the milled steel tube.
Furthermore, according to the invention, the pair of left and right follower forming rolls are respectively supported by sliding brackets, both the sliding brackets are respectively, in slidable contact with a pair of left and right tapered blocks screwed onto an adjusting screw shaft, and the tapered blocks are simultaneously moved oppositely to each other along said adjusting screw shaft whether toward each other or away from each other by rotation of the adjusting screw shaft. Thus, it is possible to slide the sliding brackets symmetrically concerning a center of the main forming roll and in the same movements by only rotating the single adjusting screw shaft, so that a fine adjustment of the diameter of the finished product can be made swiftly while inspecting the diameter during the process by the reducing mill.
Additionally, according to the present invention, each of the sliding brackets is formed with a sliding face in parallel to each of the tangents, and a stand structure supporting the three forming rolls is formed with a pair of left and right sloped faces in parallel to the respective tangents, so that the sloped faces are brought into slidable contact with the sliding faces of the respective sliding brackets. Therefore, the sliding brackets are moved along the respective tangents while their sliding faces slide on the respective sloped faces during the movement of the tapered blocks by rotational operation of the adjusting screw shaft.
In addition to the above adjustment on basis of the inspection of the diameter on-line, the adjustment of roll positions can be also made corresponding to a difference of a springback caused by variation of the steel in material, thereby maintaining an extremely satisfactory accuracy of the finished diameter of the product.
Other objects, features and advantages of the present invention will become clear from the following description by reference to the accompanying drawings.
REFERENCES:
patent: 3584490 (1971-06-01), Bindernagel
patent: 3987657 (1976-10-01), Properzi
patent: 4313325 (1982-02-01), Staat et al.
patent: 4569217 (1986-02-01), Properzi
patent: 6116071 (2000-09-01), Cernuschi et al.
patent: 3143244 A1 (1983-05-01), None
patent: 9-262620 (1997-07-01), None
Kusakabe Electric & Machinery Co. Ltd.
Sterne Kessler Goldstein & Fox P.L.L.C.
Tolan Ed
LandOfFree
Three-roll-type reducing mill for electro-resistance-welded... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Three-roll-type reducing mill for electro-resistance-welded..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Three-roll-type reducing mill for electro-resistance-welded... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2551613