CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Provisional Patent Application Ser. No. 60/564,067 filed on Apr. 21, 2004.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to rolling mills producing hot rolled long products, e.g., bars, rods and the like, and is concerned in particular with the provision of an improved system for subdividing such products, with acceptable customer lengths being delivered to a cooling bed, and with unacceptable front and tail ends being diverted to a chopping shear.

2. Description of the Prior Art

Conventional systems of the above-mentioned type typically involve laterally diverting the hot rolled product from one path to another, usually by switches acting in concert with flying shears and the like. However, for certain products, particularly those with increased stiffness, other than minor lateral diversions of the unacceptable front and tail ends can prove to be problematical, resulting in a cobble and an interruption of the rolling process.

The principal objective of the present invention is to minimize the extent to which unacceptable front and tail ends are diverted on their way to the chopping shear, thus avoiding or at least significantly reducing the risk of cobbling.

SUMMARY OF THE INVENTION

In accordance with the present invention, hot rolled product lengths exiting from a rolling mill along a first path are directed to a first switch which acts in concert with a first shear to subdivide each product length into successive segments including a front end segment, a plurality of intermediate segments, and a tail end segment. The successive segments are alternately delivered from the first shear to one or the other of two adjacent downstream second paths. Second switches on the second paths are selectively adjustable between first positions allowing the intermediate segments to continue along the second paths to a downstream cooling bed, and second positions diverting the front or tail end segments from the second paths to third paths. A second shear operates to chop the front and tail end segments traveling along the third paths into scrap lengths that are delivered to scrap receptacles.

The second paths are arranged between the third paths to thereby minimize the deflection of the front and tail ends by the second switches.

These and other features and advantages of the present invention will now be described in greater detail with reference to the accompanying drawings; wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view of a system in accordance with the present invention;

FIG. 2 is an enlarged front view of the second shear;

FIG. 3 is a diagrammatic representation of the successive segments produced by the first shear;

FIG. 4 is a more detailed plan view of the arrangement of switches and shears shown in FIG. 1;

FIG. 5 is an end view of the second shear; and

FIG. 6 is a sectional view taken along line 6-6 of FIG. 5.

DETAILED DESCRIPTION

With reference initially to the schematic illustrations of FIGS. 1 and 2, a system in accordance with the present invention is shown at 10 at a location along the mill pass line â€œXâ€ between the last roll stand RS of the mill and a cooling bed CB.

A first switch SW₁operates in concert with a first shear SH₁to subdivide the product lengths into successive segments, including front end segments, intermediate segments, and tail end segments. The intermediate segments comprise metallurgically acceptable customer lengths destined for delivery to the cooling bed. Depending on the type of product being produced, the front end segments may be metallurgically unacceptable due to inadequate upstream cooling. The tail end segments are often shorter than the desired customer length. The successive segments exiting from shear SH₁are alternately received on adjacent downstream second paths A,B.

The subdivided segments moving along path A are directed to a second switch SW₂which is adjustable to either allow the acceptable intermediate segments to continue along path A or to deflect front and tail end segments to a different path C₁. The subdivided segments traveling along path B are similarly directed to a third switch SW₃which also is adjustable either to allow the acceptable intermediate segments to continue along path B or to deflect front and tail end segments to a different path C₂.

A chopping shear SH₂is located downstream from the switches SW₂,SW₃. As can best be seen in FIG. 2, the shear SH₂has two sets of coacting shear blades B₁,B₁and B₂,B₂aligned respectively on paths C₁, C₂. The paths A, B pass freely between the laterally spaced blade sets of the chopping shear. On the downstream side of shear SH₂, the paths C₁, C₂lead to crop receptacles CR, and the paths A, B continue to the cooling bed CB.

With reference to FIG. 3, in an exemplary sequence, the shears SH₁would operate to subdivide billet lengths of product delivered from the last roll stand RS into a short front end segment L₁of metallurgically unacceptable product, intermediate segments typically comprising acceptable customer lengths L₂-L₅, and as is more often than not, an unacceptably short tail end segment L₆.

The switches SW₂,SW₃would then process these segments as shown below in Table A.

TABLE AProductPATHSCooling BedCrop ReceptacleLengthsABC₁C₂Shear SH₂CBCRL₁xxxxL₂xxL₃xxL₄xxL₅xxL₆xxxx

The foregoing sequence is merely illustrative and will vary depending on the type of product being handled, the customer lengths into which it is to be subdivided, etc.

A more detailed illustration of the switches and shears of the present invention can be seen by reference to FIGS. 4-6. From FIG. 4, it will be seen that the switch SW, comprises a guide pipe 12 mounted for movement about a pivot 14, and pivotally adjustable to deliver products through shear SH₁to paths A,B by a piston-cylinder unit 16. The shear SH₁may be of conventional design well known to those skilled in the art.

An entry guide 18 directs segments passing along paths A,B to respective switches SW₂,SW₃, each being mounted for movement about a pivot 20. Switch SW₂is adjustable by a piston-cylinder unit 22 to allow acceptable intermediate segments to continue along path A to the cooling bed, or to divert unacceptable front and tail end segments to path C₁. Switch SW₃is similarly adjustable by a piston-cylinder unit 24 to allow acceptable intermediate segments to continue along path B, or alternatively, to divert unacceptable front and tail end segments to path C₂.

As can be seen from FIGS. 5 and 6, the chopping shear SH₂has parallel shafts 26 carrying intermeshed gears 28. The lower shaft 26 is driven by a motor 30 (shown in FIG. 1). The externally projecting ends of the shafts carry the laterally spaced pairs of coacting shear blades B₁,B₁and B₂,B₂aligned respectively on the paths C₁,C₂. Guides 32 direct product segments along paths A,B between the chopping shear blades.

With the above described arrangement, the switches SW₂,SW₃need only pivot through small angles in order to deflect product end segments from the paths A,B to their respective diversion paths C₁,C₂. In this manner, the front and tail end segments of relatively stiff products, e.g., those with larger diameters and/or lower temperatures, can be processed without the risk of cobbling.