EP0088347B1 - Apparatus for keeping the tension of metal strips at a constant level - Google Patents

Abstract

Strip processing lines require tension or back tension to be applied to the strip, as the case may be. These requirements are best met by the proposed chain bridle. The recoiling of adjacent slit strips on a tension reel will result in varying rewinding speeds and tensions due to the different thickness of the individual strands. Thick strands will be rewound too tight and thin strip too loose. Therefore, the chain bridle is installed before the tension reel to keep the tension of the various strands or a wide strip at a constant value. The strip (1) is clamped between two circulating chain systems (4a,4b), one arranged below and the other above the strip passline. One chain system (4b) is fixed, the other one (4a) is adjustable. The chain segments (4) of the chain systems (4a,4b) are provided with a covering and are moved parallel to the strip (1) through support rolls (5) and guide gibs (6a) with entry and exit guide curves (6) with the latter ensuring an adequate clamping pressure of the relevant opposite chain segments (4). The segment covering (7) may consist of an elastic coating (11) provided with additional shapes or profiled surfaces (12).

Description

The invention relates to a device for pulling or braking metal strips, in particular narrow strips to be wound together, with strip-wise separate braking action, preferably in strip lines between two oppositely arranged, endlessly rotating and mutually compressible clamping elements.

Metal strip is preferably moved in strip treatment plants with drivers or pull and brake roller systems. The necessary belt tension is generated in such a system in addition to drivers and reels, especially with tension and brake roller systems. The rollers are driven and more or less wrapped around the belt. The strip hoists can only be set up or taken down from roll to roll within very specific limits. The belt deflections require additional drive power and are undesirable for metallurgical and technological reasons. In practice, for reasons of cost, the roll diameters are chosen so that parts of the strip are plastically deformed even with small strip thicknesses. These disadvantages are of particular importance for thicker strips, for stainless steel strips, for special qualities such as silicon strip and surface-sensitive strips.

From GB-A 2 072152 a device is known in which a metal band is clamped between two driven, endlessly rotating friction systems. For this purpose, two belts arranged opposite one another in a machine frame and deflected by guide and drive rollers are provided, which hold the metal strip between them. Tensioning occurs when one belt is turned against the other belt by means of a hydraulic cylinder.

The disadvantages listed here are eliminated by the chain pulling machine described below. Further advantages of this device are that the propulsion is gentle on the surface, since no relative movements take place and the specific load can be kept very low, the space requirement is particularly low when there is a large train difference and with larger strip thicknesses, and the cost calculations are also considerably cheaper.

The chain pulling and braking device can be used in particular as a brake scaffold in splitting systems.

When winding narrow-band slit strips on a reel, different winding diameters and thus different winding speeds and tensions arise due to thickness deviations, which are due to the geometry of a rolled broad band, of the strip strips wound next to one another on the reel. The thick strips of tape are therefore too tight and the thin strips are wound too loosely.

In order to achieve uniform narrow bundles, restraint or braking devices are therefore already known, which compensate for different strip tension when winding narrow strips even without direct action on the surfaces of the split strips by means of band brakes. A known retaining device (DE-PS 1 804178) consists of several rings which are rotatably arranged under friction on a shaft upstream of the reel. The braking torque can be adjusted to a maximum belt tension by means of an axially supplied pressure medium, the braking torque being transmitted to the flanks of the ring hubs by means of friction disks which are inserted between the rings. If higher stresses occur, the corresponding rings perform compensating rotary movements relative to the shaft and to the other rings. The design of these restraint devices with a large number of brake disks to be machined precisely and braking surfaces provided on the ring hubs is very complex. In addition, it is disadvantageous that a device is required which has to apply the preference in order to subsequently be able to reinforce the train.

The invention has for its object to avoid the aforementioned disadvantages and to provide a simple and reliable device for keeping the tension constant for split strips and unsplit strips, without the need for an additional preferred device. When pulling out wide strip material from a tension-free strip slack, the strip tending to run sideways, the complex control driver can be omitted, since the right-angled entry of the strip is achieved by the twisting movement of the chain pulling and braking device.

According to the invention, the object is achieved in that the metal strip is clamped in parallel between two circulating chain systems and each chain system circulating by means of chains and sprockets has a plurality of chain segments placed one behind the other and arranged opposite one another in pairs above and below the metal strip and which can be pressed against the metal strip. Has friction elements. According to further refinements of the invention, it is provided that the support segments are guided coaxially to the belt, lie opposite one another in pairs, the contact surfaces with the metal belt receive a high coefficient of friction and with the support surface a low coefficient of friction or rolling support, and due to the profile and the degree of hardness Coating and its thickness, the elasticity can be metered.

This makes it possible to hold back the tape without relative movement between the tape and the contact surface of the covering and to keep the surface free of all changes in the case of sensitive tapes. The support rollers are fed to the support area via a run-up curve, so that the respective chain segment is smoothly taken over.

The chain brake device is in Spaltanla gene preferably adjusted according to the lowest strip speed. The strip strips with the faster strip speeds have an advance in the contact area of the chain brake device. The associated different lengths of the slit band are compensated for by the elasticity of the covering, which is initially compressed and allows resilience in the area of the respective advance. The specific tension in the strip strip cross section changes only insignificantly, since the pressure forces can be distributed over a relatively large area. These relationships are shown schematically in FIGS. 5-5b, the strip speed = peripheral speed according to FIG. 5; according to FIG. 5a the strip speed is> peripheral speed and according to FIG. 5b the strip speed is »peripheral speed. It is also an important effect that the design of the start-up curves enables a prestress to be applied to the covering, which is expediently designed as a stud.

With the pulling and retention device created in this way, the narrow-band slit strips can be wound up with uniform tension regardless of thickness differences. The pulling or braking forces can be regulated continuously over a wide range using the contact pressure of the chain systems. The transferable forces can be significantly increased by using additional chain wheels or support structures within the chain systems.

The chain pulling and braking device can still be used wherever the so-called S-roller units are used in belt treatment lines. A particular advantage is that the required belt tension can be brought up to the maximum belt tension required in practice, even with preference = 0.

Stretch-bending straightening units are provided with up to 5 S-rolls in front of and behind the bending stand so that the necessary strip tension can be applied. It is advisable to equip each individual S-roll with a separate GS drive or, in the case of mechanical coupling, with a GS compensating drive. This is necessary because, due to the manufacturing tolerances and the uneven wear of the S-roll coatings, relative speeds have to be avoided. This leads to a considerable expenditure of mechanical and electrical equipment as well as a large space requirement. When using the chain pulling and braking device proposed by me, only one scaffold in front of and behind the stretch-bending straightening unit is necessary. Only two GS drives are required.

In modern strip treatment plants, it is expedient to arrange a strip center control unit in front of each S-roll unit so that the strip is fed to the S-roll unit in the center of the system. A special embodiment of the chain pulling and braking device provides that the rectangular entry of the band into the device is achieved by means of a pivoting movement in the band pass plane. This process can be automated.

If the chain pulling and braking device is arranged in front of the take-up reel, it is a special embodiment that the device is adjusted according to the continuously changing entry angle of the incoming strip. This arrangement has the advantage that the tape retraction is applied immediately before the take-up reel.

• Fig. 1 die schematische Darstellung der Seitenansicht und eines Schnittes entlang der Linie 111-111 der Fig. 2 einer Kettenzieh- und Bremsvorrichtung mit den erfindungsgemässen Kettensystemen,
• Fig. 2 einen Schnitt entlang der Linie I-I der Fig.1,
• Fig. 3 einen Schnitt entlang der Linie II-II der Fig.1,
• Fig. 4 einen Teilabschnitt der Ketten mit Beschichtung
• Fig. 4a einen Schnitt entlang der Linie IV-IV der Fig. 4 und
• Fig. 5, 5a, 5b eine schematische Darstellung der Fasern in der Beschichtung an verschiedenen Positionen.

In the drawings, an embodiment of a tensioning device according to the invention is shown and show

• 1 is a schematic representation of the side view and a section along the line 111-111 of FIG. 2 of a chain pulling and braking device with the chain systems according to the invention,
• 2 shows a section along the line II of FIG. 1,
• 3 shows a section along the line II-II of FIG. 1,
• Fig. 4 shows a portion of the chains with coating
• Fig. 4a is a section along the line IV-IV of Fig. 4 and
• 5, 5a, 5b show a schematic representation of the fibers in the coating at different positions.

If the chain pulling and braking device is used in a gap line as a brake stand, the narrow belts would be fed from a splitting shear, not shown, via a loop storage device with a deflection roller and then through the chain brake device via a further deflection roller to the take-up reel. The actual chain brake device remains unchanged in all gap programs.

The chain system is preferably operated by a direct current motor with a comb gear connected downstream. The braking torques are passed on via the shaft 2 to the chain wheels 3 and to the chain segments. The support rollers 5 transmit the torques once and support the segments 4 in the driving area via guide strips 6a with support curves 6 in the inlet and outlet and brace the belt 1 by chain segments 4 lying opposite each other over the segment coating 7, which as an elastic covering 11 with a profile 12 can be executed.

The lower chain system 4b is fixed, while the upper chain system 4a is adjustable. The contact forces are adjustable. The chains are pretensioned by means of cylinder 8, which displaces a guided bearing housing 9. The oscillating rotating brush 10 removes all possible contamination and buildup on the contact surfaces.

A special application form provides that the fixed chain system is designed as a swing arm construction 13. This ensures that the chain pulling and braking device can be inclined to a certain angle in accordance with the incoming belt.

The control frame 14 has the task, if the tape does not run at 90 ° on the segments 4, to rotate the entire chain pulling and braking device in the tape plane until the right-angled tape inlet is restored. Automatic control is state of the art.

Claims (10)

1. Apparatus for pulling or braking metal strips (1), especially narrow strips to be reeled up jointly with braking action separate for each strip, preferably in strip lines, between two opposedly situated, endlessly circulating clamping elements which can be pressed against one another, characterized in that the metal strip (1) is clamped parallel between two chain systems (4a, 4b), and each chain system (4a, 4b), circulating by means of chains and chain wheels, comprises a plurality of chain segments or friction elements (4), placed one behind another, disposed in pairs above and below the metal strip (1) opposite to one another, and able to be pressed onto the metal band.

2. Apparatus according to Claim 1, characterized in that the chain segments (4) of the chain systems (4a, 4b) possess segment coatings (7).

3. Apparatus according to Claim 2, characterized in that an unchanged position of the mutually facing segment coatings (7) is achieved by a form-fitting drive connection through rollers (5) and guide bars (6a).

4. Apparatus according to Claims 1 to 3, characterized in that the chain segments (4) are provided with an elastic facing (11).

5. Apparatus according to Claim 4, characterized in that the elastic facing (11) is equipped with a profiling.

6. Apparatus according to Claims 1 to 5, characterized in that the chain segments (4) are supported by means of rollers (5).

7. Apparatus according to Claims 1 to 5, characterized in that the chain segments (4) are selectively supported by means of sliding surfaces.

8. Apparatus according to Claim 3, characterized in that the guide bar (6a) is provided with inlet and outlet curves or inclines (6).

9. Apparatus according to Claims 1 to 8, characterized in that the chain pulling and braking apparatus rests on an adjusting frame.

10. Apparatus according to Claims 1 to 9, characterized in that the chain pulling and braking apparatus rests on a pivotally mounted structure.

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