Rod Entry Guide

Abstract

Mechanism consisting of a large driven pulley and a plurality of small rollers aligned along about 90.degree. of the periphery of the driven pulley for changing the direction of rolled rod coming from a rod mill from horizontal to vertical for delivery to a laying reel or other rod collecting mechanism. The small rollers in one form are carried by pivoted arms mounted on a support and are individually spring-pressed toward the driven pulley permitting acceptance therebetween of the oncoming rod and the application of correct pressure against the rod as it changes direction from horizontal to vertical. In another form, the small rollers are carried by the links of a chain extending along the driven pulley perimeter. The chain is spring-loaded to permit entry of the rod and between the pulley and rollers.

Description

BACKGROUND OF THE INVENTION

This invention relates to an apparatus for a rod mill that will accommodate itself to any rod delivery speed and act to change the direction of travel, in particular from horizontal to vertical, of hot metal rods. The mechanism comprises a rotating pulley and cooperating rotatable members, preferably in the form of small rollers, which together with intermediate fixed guide members set at an angle to correspond to the angle of deflection of said pulley's periphery, form the track along which the metal rod is guided. Such apparatus is typically installed at the dis-charge end of a horizontally arranged water-quenching pipe. acts to change the direction of rod travel from horizontal to vertical and directs the rod through a vertical guide into a coiling reel. An early form of mechanism using small outer rollers in in combination with a fixed inner track is shown in the German Utility Model Application No. 1,776,823 of 1958.

Another known apparatus of this type is the so-called chain guide, one form of which is shown in U.S. Pat. No. 3,100,070. This features a large driven pulley ranging from 32 inches to 40 inches in diameter, provided with a groove about its periphery. Thereabove, in a pivoted arm, is a spring-loaded yoke, in which two smaller pulleys are mounted. A flexible toothed chain is passed around these pulleys. When the pivoted arm is swung downward, the links in the lower strand of the chain make contact with the working face of the large driven pulley over an angle of approximately 90.degree.. In some prior art means, the back of the chain faces the rod and in others the teeth are directed toward the rod. By adjusting a spring, the pressure applied by the chain to the driven pulley can be varied. The front end of the approaching rod drives between the periphery of the pulley and chain. The frictional forces between the pulley, wire rod and chain enable the requisite forces to be generated for applying tension to the rod and changing the direction of rod travel.

Such prior art chain guides have proved to be thoroughly satisfactory for handling rod from rolling mills operated at fairly slow speeds. But with increasing rates of rod travel, the strain on the chains is disproportionately increased. From practical experience gained with rod mills all over the world, the maximum rate of rod travel that permits economic use of chain guides is approximately 7860 feet per minute. If the rod emerges from the finishing stand at a higher speed, the service life of the chains is substantially curtailed; frequently, chains fracture after only a few working hours. The chains are fairly costly as they are manufactured from high-grade special steel and are produced by only a few specialist firms. Additional costs are entailed in that each time a chain breaks, the billet in process is scrapped and operation of the mill has to be stopped pending the fitting of a replacement chain and the removal of the scrap material.

By virtue of the aforedescribed shortcomings, those skilled in the art sought an alternative solution to said chain guides. An apparatus was developed that incorporated two rotating pulleys. One of these pulleys was provided with a groove about its periphery. The other slightly larger pulley was provided with a flange-like ring on one side. The larger pulley is positioned alongside and at a slight angle to said smaller pulley, so that the inner face of said flange-like ring of the larger pulley overlaps the peripheral face of said smaller pulley over a distance corresponding to an angle of deflection of approximately 90.degree.. A gap of approximately 0.02 inch is left between the peripheral face of said smaller pulley and the inner face of the ring of said larger pulley. With this type of construction, guidance of the rod is effected by the groove in said smaller pulley and the tensioning function is performed by said larger pulley, whereby the centrifugal forces generated by the changing direction of the rod effect internal contact between said rod and the inner face of said ring, the rod being entrained by friction. Broadly speaking, the smaller pulley of this apparatus corresponds to the driven pulley of the chain guide and the ring on the larger pulley takes the place of the chain.

Tests proved that this so-called centrifugal force or pulley guide was functionally adequate. It permitted the handling of rod emerging from the rolling mill at speeds up to and in excess of 9,840 feet per minute, and no major difficulties were encountered in normal rolling conditions. However, it was soon discovered that a substantial drawback of this apparatus derived from the relative movements in the axial direction of the pulleys, causing trouble at the entry and exit bell mouths. The working face on the inside of the ring was subject to excessive wear. Also, the shape of the groove in the smaller pulley could not be maintained. As soon as the wear exceeded a certain amount, both pulleys had to be replaced. It was found that, as a result of the highly critical characteristics of the design, worn pulleys could not be repaired and thus had to be scrapped. This is not economically feasible. Morever, tests carried out with various materials showed that service life could not be appreciably increased to reduce to an acceptable degree the loss of production through down-times.

The object of the present invention is to provide an apparatus for handling hot metal rods of the type initially described to avoid the drawbacks of prior art devices obtaining at rod speeds in excess of 7,860 feet per minute and especially in excess of 9,840 feet per minute and affording long service life.

The invention achieves this object through the provision of a plurality of rollers which cooperate with the driven pulley. The number of said rollers should be as large as possible to minimize the intervals between the points at which the rollers are in contact with the driven pulley so as to obviate deflection of the rod especially when threading up. On the other hand, there must not be too many rollers as for geometrical reasons the diameter of the rollers would be too small resulting in rotational speeds not technically practical. It has been proved that satisfactory results are obtained with from six to ten rollers disposed over an angle of deflection of approximately 90.degree.. The diameter of the rollers should not exceed about one-fifth the diameter of the large driven pulley. A further feature of the invention is that the rollers are spring-loaded to press them against the periphery of the driven pulley. The spring pressure should be adjustable and be of sufficient magnitude to ensure that during idle running the rollers are in positive contact with and caused to rotate by the driven pulley, thus dispensing with the need to furnish the rollers with individual driving means. On the other hand, excessive spring pressure must not be exerted as this would result in deformation of the hot metal rod which usually has a temperature of 1,300.degree. to 1,650.degree. F as it passes between the driven pulley and the small rollers.

In a preferred embodiment of the invention, each of the rollers is mounted on a pivoted arm whose pivotal point, viewed in the direction of rod travel, is in front of or at the back of the roller's axis of rotation. This arrangement enables the roller to move outwardly under spring pressure when contacted by the leading end of the oncoming rod without deforming said rod. The rollers preferably are mounted on a pivoted unitary support permitting them to be moved as a group away from the driven pulley for replacement or repair.

In another embodiment of the invention, the rollers are mounted between interconnected side bars which form in effect, a chain. This roller assembly has a fixed-point mounting on the delivery side and on the entry side is kept under spring tension. This arrangement also ensures that the leading end of the rod will not be deformed as it enters the guide and that the distance and pressure between the rollers and driven pulley may be varied to suit the working conditions.

In spite of the fact that the intervals between the points at which the relatively large number of rollers are in contact with the driven pulley are fairly small, it has proved advisable to install further guide members in the intermediate spaces.

Rollers provided with a shell of cemented carbide material or manufactured of cemented carbide throughout have an exceptionally long service life.

Pressure exerted on the rod can be automatically adjusted to suit the rate of rod travel by another feature of the invention whereby pivoted guide members of offset arrangement are disposed about the periphery of the driven pulley. These members, which swing outwardly under centrifugal force, form a guideway for the rod and their outward movement is limited by a ring associated with the driven pulley.

To achieve optimum uniformity of frictional contact, irrespective of the size of rod handled, it is advisable to furnish the driven pulley with a plurality of pass sizes. By having the pulley shiftable in an axial direction, the appropriate pass may be brought into alignment with the delivered rod without the need for a switch. In such case, the small wheels which do not change position have only a single groove. Alternatively, when the driven pulley is not axially shiftable, a switch on the entry side may be used to direct the rod to the correct pass. In this latter case, the small wheels would have a plurality of passes aligned with the driven pulley passes.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention will now be explained with the aid of drawings showing schematic views, whereby

FIG. 1 is a vertical section through the apparatus at right angles to the axis of the driven pulley.

FIG. 2 is a section taken along the line 2--2 of FIG. 1.

FIG. 3 is a plan view of a switch.

FIG. 4 is a section through a roller of the type shown in FIG. 1.

FIG. 5 is a side elevation similar to FIG. 1 of another embodiment of the invention.

FIG. 6 is a section taken on the line 6--6 of FIG. 5.

FIG. 7 is a fragmentary side elevation in much larger scale of another embodiment of the invention.

FIG. 8 is a section taken on the line 8--8 of FIG. 7.

FIG. 9 shows an embodiment to larger scale of the invention generally as shown in FIG. 1, but with a driven pulley of different arrangement.

FIG. 10 is a section taken on the line 10--10 of FIG. 9.

DESCRIPTION OF A PREFERRED EMBODIMENT

Pulley 1 is driven by an electric motor, not illustrated, and is mounted in a base member, also not illustrated, anchored to the foundation. The driven pulley is preferably from 32 inches to 36 inches in diameter. A three-sided roller box, or housing 2, pivoted on pivot 3 is also mounted on the base member. The roller box which acts as a support for small rollers 7 can be raised from its working position, for servicing and maintenance purposes, for example, by means of a hydraulic piston and cylinder assembly 4, pivotally attached at 5 to the box 2.

Rollers 7 mounted on pivots extending between the ears of inverted U-shaped members 6 are contained in the roller box 2. Members 6 are pivoted on link pins 8 extending across box 2. The pins are located ahead of the axes 20 of the rollers 7 viewed in the direction of rod travel. The rollers 7 are preferably individually spring-loaded with the aid of adjustable springs 9 positioned above the axes of the rollers. Between the individual rollers 7 are spacers 10 preferably attached to the housing 2 which can be adjusted in the radial and circumferential directions with the aid of mechanical means not illustrated. The side of each spacer 10 facing the driven pulley 1 has a curve corresponding to the radius as from the center of the driven pulley 1. On the entry side, the roller box 2 carries an entry bell mouth 11 through which the rod 12 is guided in the direction indicated by the arrow 13. An exit bell mouth 11a is provided on the delivery side.

As is best illustrated in FIGS. 2 and 3, the driven pulley 1 has two passes 14 and 15, of different sizes. If desired, said pulley can be furnished with more passes. But is has been proved in practice that there is no need for a separate pass for each size of rod rolled. Two sizes of passes are adequate to accommodate most sizes of rod. The rollers 7 are also provided with two passes 16 and 17 which, in the embodiment illustrated in FIG. 4, are of the same size. The rollers 7 have a cemented carbide shell 18 (see FIG. 4) to reduce wear. They are mounted in ball bearings 19 and in view of the high rotational speeds of the rollers 7, up to approximately 8,500 rpm, are preferably furnished with mist lubrication and air cooling means (not shown) through spindle 20.

In the embodiments shown in FIGS. 5 and 6, the individual rollers 7 are mounted between side plates 30 and 31, the spindles of the individual rollers simultaneously serving as link pins for side plates 30 and 31. This roller assembly is pivotally attached at the delivery side to a side plate 34 by means of a link pin 33 and, with a bolt 35 passing through a slot in side plate 34, is fixed to the underside of the roller box 2. Side plate 34 can be displaced in the horizontal direction with the aid of adjusting nuts 36 and 37 assembled on a threaded pin 38 welded to side plate 34, and engaging on both sides a tongue 39 welded to the roller box. On the entry side, the roller assembly is attached to an angle lever 40 which is rotatable on a pivot 41. Tensional force is applied to the roller assembly through spring 42 acting on angle lever 40. The spring 42 is adjustable by means of nut 43 located on the turnbuckle 44.

In this embodiment, the rollers 7 also have a cemented carbide shell. As distinct from the embodiment first described, the rollers 7 and the driven pulley 1 have only one pass.

In the embodiment illustrated in FIGS. 7 and 8, the rollers 7 are mounted in a manner similar to that depicted in FIGS. 1 and 2. But the difference in this case is that guide members 46 are fixed to the spaced ears of members 6 by bolts 47 and are therefore able to move outwards with roller 7 as the leading end of the rod enters the pass. Impact upon the static guide members 46 is thereby obviated. The guide members 46 are also provided with a corresponding pass 48 and are preferably manufactured from cemented carbide steel. As will be seen in FIG. 8, the driven pulley 1 comprises a circular disc to which is welded a cylindrical tire.

In the embodiments shown in FIGS. 9 and 10, the rollers 7 are mounted in a manner similar to that depicted in FIGS. 1 and 2. The driven pulley 1' is, however, of different fabrication. As depicted in FIG. 9, it incorporates a ring disc 49, L-shaped in cross-section, to which a ring 50 is fixed with screws 51. As a result, an annular groove is produced. Slide members 53 are pivotally mounted off-center in said annular groove by bolts 52. The slide members 53 are preferably of cemented carbide material and furnished with a pass 54. When the driven pulley 1' rotates the slide members 53 swing outwards under the influence of centrifugal force. They are limited in movement in the radial direction by a collar 55 incorporated in the annular groove. The distance between the individual slide members 53 must be kept as small as possible.

In the course of trials, it was established that the apparatus disclosed by the invention is able to handle rod with utmost dependability at substantially higher rates of travel than was possible with prior art means and is practically immune to troubles. As the rollers 7 have an outer shell of cemented carbide they have an exceptionally long service life. One of the major advantages of the invention is that most wear parts can be wholly or partly of cemented carbide. In prior art devices for handling hot metal rods, the components that are subject to severe abrasive wear are either of a shape or size that prevent the use of cemented carbides.

Modifications and further applications of the invention will now be apparent to those skilled in the art without department from the spirit of the invention.

Claims

We claim:

1. Means in a rod mill for changing the direction of travel of a rapidly moving bendable rod, said means comprising a main driven grooved pulley about which said rod passes, a plurality of rotatable small grooved rollers mounted adjacent said main pulley for engaging and holding said rod against said main pulley as the direction of the moving rod changes, said small rollers being closely adjacent each other and aligned with said main pulley and extending along the periphery of said main pulley for an angular distance substantially equal to the desired angular change in direction of said rod, and guide members spaced radially from the periphery of said main pulley and positioned between said small rollers.

2. The means set forth in claim 1, said small rollers being movable toward and away from said driven pulley and resilient means for continuously urging said small rollers toward said main pulley to hold said rod therebetween and in the absence of rod to hold said small rollers against said driven pulley to cause them to rotate.

3. The means set forth in claim 1, the diameter of said small rollers being not more than one-fifth the diameter of said main pulley.

4. Means as set forth in claim 1, the mounting for said rollers comprising a curved support, each small roller being mounted for rotation on an arm which is pivoted to said support, the pivot of each said arm being angularly displaced with respect to said main pulley from the axis of its said roller.

5. Means as set forth in claim 4, and spring means acting against each said arm to urge said small rollers toward said main pulley.

6. Means as set forth in claim 4, the pivot of each said arm being at a greater distance from the axis of said main pulley than the axis of its said roller.

7. Means as set forth in claim 1, said small rollers being mounted between interconnected pairs of side plates forming a chain-like assembly.

8. Means as set forth in claim 7, the said chain-like assembly formed by the said pairs of side plates having a fixed point of connection on the delivery side of said pulley and having a spring on the entry side of said pulley urging said small rollers toward said pulley.

9. Means as set forth in claim 1, said small rollers comprised of cemented carbide.

10. Means as set forth in claim 1, the rod engaging periphery of said driven pulley comprised of a plurality of successive guide members pivoted to said pulley which members may swing outwardly under centrifugal force as said pulley rotates and means on said pulley for limiting the outward movement of said guide members.

11. Means as set forth in claim 1, said driven pulley and said rollers having a plurality of passes and a switch on the entry side of said driven pulley for directing the leading end of an oncoming rod to a selected pass.

12. Means as set forth in claim 1, said driven pulley having a plurality of passes and means whereby said oncoming rod can be directed into a selected driven pulley pass.

13. Means in a rolling mill for changing the direction of travel of a rapidly moving bendable product, said means comprising: a main driven grooved pulley about which the product passes; a plurality of rotatable small grooved rollers mounted adjacent to said main pulley for engaging and holding the product against said main pulley as the direction of the moving product changes, said rollers being closely adjacent each other and aligned with said main pulley and extending along the periphery of said main pulley for an angular distance substantially equal to the desired angular change in direction of the product, the mounting for said rollers including a curved support, each of said rollers being rotatably carried on an arm which is pivoted to said support, the pivot of each said arm being angularly displaced with respect to said main pulley from the axis of its said roller, and guide members secured to said support between said rollers, said guide members being spaced radially from the periphery of said main pulley.

14. The means as claimed in claim 13 wherein said curved support is mounted for pivotal movement relative to said main pulley between a closed operative position at which said rollers are in contact with said main pulley in the absence of product therebetween, and an open inoperative position at which said rollers are remote from the main pulley and accessable for inspection and replacement.