US3268181A - Coil expander - Google Patents

Description

I Aug. 23, 1966 R. RAHN 3,268,181

COIL E XXXXX ER Original Filed June 28, 1962 United States Patent 3,268,181 COIL EXPANDER Richard Rahn, Dusseldorf, Germany, assignor to Schloemann Aktiengesellschaft, Dusseldorf, Germany, a company of Germany Original application June 28, 1962, Ser. No. 205,975, now Patent No. 3,216,671, dated Nov. 9, 1965. Divided and this application May 18, 1965, Ser. No. 456,777 Claims priority, application Germany, July 25, 1961, Sch 30,037 Claims. (Cl. 24278.1)

This application is a division of my application Ser. No. 205,975, filed June 28, 1962, now Patent No. 3,216,- 671, which issued November 9, 1965.

The products coming from a cold-rolling mill are as a rule annealed, after the cold-rolling, in an atmosphere of protective gas. Sheet-iron strips, which require to be maintained at the annealing temperature for rather a long time, are usually annealed in a coiled condition, that is to say, as a complete bunch or coil. Now it is known that during annealing in an atmosphere of protective gas, as loose a Stratification as possible of the material to be annealed leads to a better scavenging of the stack of material that is being annealed with the protective gas, and therefore to a better removal of impurities, a quicker heating up, and a more uniform texture-formation. Now since a bunch of strip coming from the cold-rolling mill is usually very stiff and tightly coiled, one is nowadays frequently constrained, for the purpose of obtaining a loose layering, to open out the tightly coiled bunch of strip by re-winding it, that is, by re-shaping it in such a way as to provide, between the individual turns, spaces through which the protective gas can be passed during the annealing process.

A re-winding appliance is known which serves to convert strip-iron rings of a given diameter to a larger diameter. With this appliance the strip ring to be converted is placed with one of its end faces upon a stationary table, the outer end of the strip being secured to the inner peripheral surface of a clamping ring embracing the ring of strip, and the clamping ring being set in rotation in a direction opposite to the winding direction of the strip ring, whereby the individual turns of the strip ring, advancing in an inward direction, travel outwards, and bear on the rotating clamping ring.

In another appliance on the same principle, for the better centering of the strip ring, a mandrel penetrating cen trally through the bearing surface is provided, or else a row of concentrically arranged rods are secured upon the bearing surface, and it is the mandrel, with the ring of strip mounted thereon, that is set in rotation, instead of the outer casing. Here the bearing surface is divided into an inner disc and an outer ring, and the inner disc revolves along with the mandrel. It Would of course also be possible to let the mandrel, with the tightly coiled bunch mounted thereon, turn in the opposite direction simultaneously with the outer clamping ring.

When re-winding with such an appliance, the tensile stress usually prevailing in a tightly coiled bunch of strip can be considerably reduced, that is to say, quite loose and soft bunches can be produced. Now it has been found that in the re-coiling, particularly of thin-strips, the speed of re-winding has a great influence upon the strength of the newly formed coil, in such a way that at a high rewinding speed (a great speed of revolution of the mandrel or of the outer casing, or of both), looser coils are obtained than with a lower speed of re-winding. By tests and measurements it has been ascertained that this is effected by damming or impounding air, which, with increasing speed of winding, acts in the form of compressive and suction forces upon the turn that happens to be travelling outwards.

ice

The invention on which the problem is based, of producing opened coils with the spaces between the turns as uniform and regular as possible, harks back to the last appliances described, since these are of very simple construction, are economical in the use of space, and operate very reliably, particularly as regards injuries to the surface of the strip, the unwinding and re-winding of the strip that is otherwise usual in the production of an opened coil being obviated. Now in order to obtain the desired spacing between the individual turns, means are to be provided by which the action of the impounding of air, yielded when re-winding at a high winding speed, is reinforced in such a way that in the formation of the coil of larger diameter, the turns are prevented from coming into contact with one another.

According to the invention this object is achieved by providing in these known appliances, a cover plate covering the upper end of the coil in an airtight manner. By this means the air that is displaced from the turn that is travelling outwards cannot escape outwards, but bears like a cushion or pad between the preceding turn that is already formed and the fresh turn now being formed. At the same time, however, no air from outside can enter the interior of the coil, whereby the suction arising behind the travelling turn is reinforced. Adequate driving power must of course be provided for a sufliciently high re-winding speed.

According to a further feature of the invention, a drive maintaining a constant speed of revolution of the mandrel and/or the outer casing will be provided, so as to keep the distances between the turns uniform.

One embodiment of apparatus according to the invention is diagrammatically illustrated by way of example in the accompanying drawings, in which:

FIGURE 1 shows in section a side view of the apparatus; and

FIGURE 2 shows a plan view in section on the line IIII in FIGURE 1.

Upon a circular base-plate 1 are arranged a rather large table-ring 2, and a smaller ring 3. The table-ring 2 is rotatably supported, but the inner ring 3 is stationary, being secured non-rotatably upon the base-plate 1. The table-ring 2 is stepped up towards the periphery, comprising a raised step 2a all round, and a collar 2b projecting above the step 2a. The table-ring 2 carries a number of individual rings 4, 5, 6 and 7 of different sizes, which are arranged one in another like hearth-rings, and which are free to rotate slidingly upon the table-ring 2 independently of one another. The upper surfaces of the rings 3, 4, 5, 6 and 7 are flush with one another, so as to form a plane bearing surface for the accommodation of the bunch or coil of strip 8. In the centre of the apparatus a vertical core or mandrel 9 is provided, which serves as a pivot, and which is equipped with a clamping device 10 for the inner end of the coiled strip. If desired, the mandrel 9 may be journaled in a bearing bush 19, and driven by a motor 20. The table-ring 2 is provided with external teeth, which mesh with a toothed pinion 11, driven by a motor 18. The table-ring also carries a cylindrical outer casing 12, which is held by the collar 2b, and is provided with a number of slits 13 distributed around the periphery, in which a cover plate 14, covering the whole of the upper end of the coiled bunch 8, 8a, can be secured at an adjustable height. Means for holding fast the cover plate 14 on the mandrel 9 may of course alternatively be provided.

The apparatus according to the invention operates in the following manner: After the bunch of strip 8 to be opened has been placed upon the apparatus, and the inner end of the strip has been clamped by means of the clamping device 10, the cylindrical outer casing 12 is put on and the outer end of the strip is so far loosened that it describes a large enough circle, and can be secured to the inner wall surface of the outer casing 12 by means of a clamping device not shown. The cover plate 14 is then put on, and upon this cover plate a ring 16 is laid. Clamping screws 17, slidable in vertical guiding slots 13 in the outer casing 12, engage in the ring 16, and enable this ring and the cover plate to be secured in such a way that the cover plate just touches the upper edge of the bunch 8. The rotational drive 11 is now switched on, this being so arranged that the table ring 2, and with it the outer casing 12 also, revolve at a high speed in the direction of the arrow 15. The leading end of the strip, secured to the outer casing 12, is carried round with the casing, with the result that the strip section, extending in a spiral path of large pitch towards the stationary bunch, is moved outwards in an unwinding direction, towards the outer end of the strip, or, in other words, towards the outer casing 12, a corresponding fresh section of a turn being from time to time lifted off the tightly Wound bunch. On the basis of the high speed of revolution, the outwardly travelling turns move very quickly, so that the air impelled by the turn that is running oif forms a sort of thrust wave, whilst'at the same time, behind this turn, there is suction. Now since, owing to the covering of the upper end of the coil, air cannot escape outwards, nor can atmospheric air enter the winding space, and the equalization of air in the Winding space is itself subject to a certain time lag, the pressure and suction forces occurring are strong enough to preclude the outwardly moving turn section from contact with the turn previously formed. When once a turn section has come to a standstill, it does not undergo any further displacement.

It is in order as far as possible to obviate, in the winding operation, any grinding of the lower edge of the strip upon the bearing surface, that the bearing surface is divided into a number of individual rings 4, 5, 6 and 7. Those individual rings that are loaded by the stationary bunch 8, for instance the rings 6 and 7, are here held fast by the weight loading them, so that as the table-ring 2 is driven the latter turns beneath the rings 6 and 7. In

the course of the winding operation, turn after turn is re-.

leased from the stationary coiled bunch and moved radially outwards, so that one ring after another is relieved of load. The unloaded rings 4, 5 and 6 are then from time to time carried round by the revolving table-ring. The turns 8a, that are already released, rotating along with the outer casing 12, thus receive a bearing surface turning with them, and therefore relatively stationary.

Now in order to obtain, in the coiling operation, as high a speed of re-coiling as possible, it is of course quite possible not only to have the outer casing 12 revolving but to have the mandrel 9, with the tight coil of strip 8, also revolving, but in the opposite direction. With such an arrangement, however, care must be taken that the positively driven members, the outer casing 12 and the mandrel 9, turn at as constant a speed as possible, in order that in the opened bunch, uniform and satisfactory spaces should be formed between the turns. By changing the coiling speed, the spacing between the turns can be slightly altered.

This apparatus, which is also suitable for re-winding non-metallic strips, can however only be employed for thin Y and quite flexible strips, up to a maximum thickness of half a millimetre. An expedient for also enabling coils of thicker strip material to be opened, or for obtaining wider spacing between the individual turns, consists in filling the apparatus with a fluid heavier than air. The outwardly travelling turns will hereby be opposed by a greater weight. Such a heavier medium might for instance be carbon dioxide; and by appropriate additions of other gases a cleaning of the strip from residues of fat or oil can at the same time be effected. The apparatus must of course then be made gastight, to comply with protective regulations.

I claim:

1. Apparatus for re-shaping a tightly coiled bunch of strip material into an opened bunch with spaced turns, comprising: a base-plate, a plane bearing surface for the endwise mounting of the tightly coiled bunch of strip, the bearing surface cosnisting of a number of concentric rings resting on the base-plate and slidingly rotatable independently of the base-plate and independently of one another, a central mandrel extending upwards through the said bearing surfam, a cylindrical outer casing surrounding the bearing surface, a clamping device for securing the outer end of the strip to the outer casing, and a cover plate adapted to rest in a substantially airtight manner on the top end of a coil of strip located within the cylindrical outer casing, so that by rotating the outer casing relatively to the mandrel, turn after turn of the strip is lifted away from the tightly coiled bunch and moved outwards towards the outer casing.

2. Apparatus for re-shaping a tightly coiled bunch of strip material into an opened bunch with spaced turns as claimed in claim 1, further comprising means for fixing the cover plate at an adjustable height.

3. Apparatus for re-shaping a tightly coiled bunch of strip material into an opened bunch with spaced turns as claimed in claim 1, further comprising a drive adapted to keep the re-winding speed constant.

4. Apparatus for re-shaping a tightly coiledbunch of strip material into an opened bunch with spaced turns as claimed in claim 1, the winding space enclosed in a gastight manner by the bearing surface, the cylindrical outer casing and the cover plate being filled with a medium that is heavier than air.

5. Apparatus for re-shaping a tightly coiled bunch of strip material into an opened bunch with spaced turns as claimed in claim 4, the said medium also including gases capable of removing contaminations such as grease from the strip.

References Cited by the Examiner UNITED STATES PATENTS 2,366,352 1/1945 Paxson 242--78.1 3,008,663 11/1961 Blackman et al. 24278.l X 3,064,918 11/1962 Keen et al. 24278.1

MERVIN STEIN, Primary Examiner.

STANLEY N. GILREATH, Examiner.

N, L. MINTZ, Assistant Examiner.

Claims (1)

1. APPARATUS FOR RE-SHAPING A TIGHTLY COILED BUNCH OF STRIP MATERIAL INTO AN OPENED BUNCH WITH SPACED TURNS, COMPRISING: A BASE-PLATE, A PLANE BEARING SURFACE FOR THE ENDWISE MOUNTING OF THE TIGHTLY COILED BUNCH OF STRIP, THE BEARING SURFACE CONSISTING OF A NUMBER OF CONCENTRIC RINGS RESTING ON THE BASE-PLATE AND SLIDINGLY ROTATABLE INDEPENDENTLY OF THE BASE-PLATE AND INDEPENDENTLY OF ONE ANOTHER, A CENTRAL MANDREL EXTENDING UPWARDS THROUGH THE SAID BEARING SURFACE, A CYLINDRICAL OUTER CASING SURROUNDING THE BEARING SURFACE, A CLAMPING DEVICE FOR SECURING THE OUTER END OF THE STRIP TO THE OUTER CASING, AND A COVER PLATE ADAPTED TO REST IN A SUBSTANTIALLY AIRTIGHT MANNER ON THE TOP END OF A COIL OF STRIP LOCATED WITHIN THE CYLINDRICAL OUTER CASING, SO THAT BY ROTATING THE OUTER CASING RELATIVELY TO THE MANDREL, TURN AFTER TURN OF THE STRIP IS LIFTED AWAY FROM THE TIGHTLY COILED BUNCH AND MOVED OUTWARDS TOWARDS THE OUTER CASING.

Images