Side Looper

Abstract

A side looper comprises an entry guide for directing a longitudinally moving long product into an arcuate path, an exit guide for receiving the product exiting from the arcuate path, and inner and outer guide walls arranged between the entry and exit guides. The guide walls are adjustable between mutually spaced closed positions fixing the curvature of the arcuate path, and open positions allowing the curvature of the arcuate path to either increase or decrease.

Description

BACKGROUND DISCUSSION

1. Field of the Invention

This invention relates generally to continuous hot rolling mills having two or more strands producing bars, rods and the like, and is concerned in particular with the provision of an improved side looper of the type employed at selected locations along the rolling lines of such mills.

2. Description of the Prior Art

As herein employed, the term “long products” is intended to encompass round bars, rods and the like, as opposed to strips and other like flat products. Also, as herein employed, the term “loop” is intended to define an arcuate deflection of the product.

During a rolling operation in a continuous hot rolling mill producing long products, it is not uncommon for the delivery speed of the product exiting from an upstream roll stand to vary from the take in speed of the next subsequent downstream roll stand. In order to deal with such speed variations, repeaters are sometimes employed between the successive roll stands. Repeaters operate to change the direction of the product by introducing a loop in the product of approximately 180°. A drawback with this arrangement, however, is that relatively large areas of the mill floor must be dedicated to accommodating the repeater loops.

Side loopers are also employed to introduce loops between the successive roll stands. Side loopers typically produce smaller loops of less than about 120°, and as such are more compact and require less mill floor space as compared to repeaters. In a side loopers, the loop is initially formed by guiding the product around a fixed arcuate guide wall, and then allowing the curvature of the loop to increase if the delivery speed of the product exiting from the upstream stand exceeds the take in speed of the downstream stand. However, should a speed imbalance result from the downstream stand's take in speed exceeding the upstream stand's delivery speed, a compensating decrease in the loop curvature is impeded by the looper's fixed guide wall, resulting in the development of unwanted tension in the product.

The present invention addresses this problem by providing a side looper designed to accommodate both increases and decreases in the curvature of the loop.

SUMMARY OF THE INVENTION

A side looper in accordance with the present invention is designed to form a loop in a longitudinally moving long product by directing the product along an arcuate path. The side looper includes an entry guide for feeding the product into the arcuate path and an exit guide for receiving the product exiting from the arcuate path. Inner and outer guide walls are arranged between the entry and exit guides. The guide walls are adjustable between mutually spaced closed positions fixing the curvature of the arcuate path, and open positions allowing the curvature of the path to either increase or decrease.

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 diagrammatic illustration of a portion of a continuous hot rolling mill employing loopers in accordance with the present invention;

FIG. 2 is an enlarged view of one of the loopers shown in FIG. 1, with the guide walls in their closed positions; and

FIG. 3 is a view similar to FIG. 2 showing the guide walls in their open position.

DETAILED DESCRIPTION

With reference initially to FIG. 1, the last strand of a two strand hot rolling mill is depicted at 10. The two product strands 12, typically round bar sections having diameters of at least 30 mm, exit roll stand 10 and are guided through side loopers 14 in accordance with the present invention before entering the roll stands 16 of two single strand continuations of the rolling mill.

With reference additionally to FIGS. 2 and 3, it will be seen that each looper 14 serves to direct the longitudinally moving long product 12 along an arcuate path P. An entry guide 18 directs the product into the path P, and an exit guide 20 receives the product exiting from the path. Inner and outer guide walls 22, 24 are arranged between the entry and exit guides. The inner wall 22 is subdivided into entry and exit sections 22a, 22b pivotally mounted as at 26 to a base structure 28, and connected as at 30 to a piston-cylinder type linear actuator 32. The outer guide wall 24 is similarly subdivided into entry and exit sections 24a, 24b pivotally mounted to the base structure as at 34, and connected as at 38 to separate linear actuators 35.

The linear actuators 32, 38 serve as operating means for adjusting the guide walls 22, 24 between mutually spaced closed positions fixing the curvature of path P, as shown in FIG. 2, and open positions as shown in FIG. 3. When the guide walls are adjusted to their open positions, the product is free to follow arcuate paths of increasing curvature, as indicated by the broken lines P_a-c, or to follow an arcuate path with a decreasing curvature, as indicated at P_d.

In operation, before a product enters the looper, the guide walls 22, 24 are adjusted to their closed positions to fix the curvature of the path P. The product is then directed via the entry guide 18 into and along the path and out through the exit guide 20. Following emergence of the product from the exit guide, the guide walls 22, 24 are adjusted to their open positions to allow the curvature of the guide path to either increase or decrease as described above, while the product continues to travel along the path and through the looper.

As soon as the product exits from the entry guide 18 and while the product is still traveling between the entry guide and the exit guide 20, the guide walls 22,24 may be adjusted to their closed positions, thus urging the tail end back to the initial confined arcuate path P. The side looper is thus quickly readied to accept the front end of the next oncoming product, which minimizes the required gap between billets being processed by the mill.

In light of the above, it will now be appreciated by those skilled in the art that the looper of the present invention is capable of not only accommodating interstand speed imbalances where the delivery speed of the upstream stand 10 exceeds the take in speed of a downstream stand 16 (guide path curvature increases as depicted at P_a-c, in FIG. 3), but also speed imbalances created by the take in speed of the downstream stand 16 exceeding the delivery speed of the upstream stand 10 (guide path curvature decreases as depicted at P_d in FIG. 3). Thus, in the latter case, the development of unwanted tension in the product is avoided.

The foregoing description has been set forth to illustrate the invention and is not intended to be limiting. Further modifications of the described embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art. For example, one such modification might comprise the translational rather than pivotal adjustment of the guide walls 22, 24 between their open and closed positions. Thus, the scope of invention should be limited solely with reference to the appended claims and equivalents thereof.

Claims

1. A side looper for directing a longitudinally moving long product along an arcuate path, said side looper comprising: an entry guide for directing the product into said arcuate path;an exit guide for receiving the product exiting from said path;inner and outer guide walls arranged between said entry and exit guides; andoperating means for adjusting said guide walls between mutually spaced closed positions fixing the curvature of said path, and open positions allowing the curvature of said path to either increase or decrease.

2. The side looper of claim 1 wherein said inner and outer guide walls are subdivided into entry and exit sections adjustable between said closed and open positions.

3. The side looper of claim 2 wherein said entry and exit sections are pivotally adjustable between said closed and open positions.

4. The side looper of claim 2 wherein the entry and exit sections of said inner guide wall are connected to and pivotally adjustable by a single linear actuator.

5. A method of directing a longitudinally moving long product along an arcuate path extending between an entry guide and an exit guide, said method comprising: fixing the curvature of said path between inner and outer guide walls adjusted to closed positions;directing the product via said entry guide into and along said path and out through said exit guide; andfollowing emergence of said product from said exit guide, adjusting said inner and outer guide walls to open positions allowing the curvature of said path to either increase or decrease while the product continues to travel along said path.

6. The method of claim 5 wherein following exit of said product from said entry guide, and while said product is traveling between said entry and exit guides, adjusting said inner and outer guide walls to said closed positions.