Abstract:
For a directly driven coiler for winding rolled strip into coils, a piston/cylinder unit is proposed which can be supplied with pressure medium through rotary feeds arranged on a shaft extension or on a coiler shaft.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a directly driven coiler for winding rolled strip into coils in accordance with the preamble of claim  1 . 
     2. Description of the Related Art 
     Such directly driven coilers have become known, for example, through DE-PS 17 52 185 or DE-OS 39 39 119. In these coilers, the relative axial displacement between the coiler shaft and the plunger connected to the segments is effected through mechanical adjustment drives. These adjustment drives are bent lever drives or spring assemblies and spacer elements which can only be actuated when the coiler stands still. Any retightening during the coiling process is not possible in these adjustment drives. 
     Piston-cylinder units have become known through DE-OS 35 02 452 by means of which it is possible to tighten and release the spring assemblies which serve as adjustment drives and have the above-described disadvantages. 
     EP-PS 0 004 854 also discloses a piston-cylinder unit which serves directly as an adjustment drive for spreading and despreading the coiler. However, these two coilers provided with piston/cylinder units are not directly driven coilers of the generic type mentioned above, but indirectly driven coilers in which the drive motor is arranged next to the coiler shaft. 
     The coiler according to EP-OS 0 004 854 does have central rotary feeds, so that, for example, retightening during the coiling procedure is possible, however, if the drive motor for the coiler were to be flanged directly to the coiler shaft, this would result in difficulties in connection with the pressure medium supply because, as a rule, only solid motor shafts are being used, so that the pressure medium could not be conducted to the piston/cylinder unit from the end of the shaft where the pressure medium is fed in. However, if the pressure medium supply is to be placed through the motor shaft, the magnetic effect in the motor could magnetize metal particles in the pressure medium and could possibly lead to clogging of the supply lines. In addition, complicated flexible pressure medium connections would have to be provided in order to bridge any lateral offsets or axial displacements between the drive unit and the coiler shaft. 
     Rotary feeds have become known through DE-PS 38 06 931 through which the pressure medium can be conveyed radially into a shaft; these rotary feeds have very narrow manufacturing tolerances for an optimum operation, wherein these very narrow manufacturing tolerances exclude a use in difficult conditions as they prevail in rolling mills. In addition, these rotary feeds can only be used up to structural sizes with a maximum 18 mm diameter at the annular gap. Also for this reason, a use in rolling mill plants, for example, rolling mill coilers, where significantly greater diameters are used, could not take place. 
     SUMMARY OF THE INVENTION 
     Therefore, the invention is based on the object of further developing a directly driven coiler of the generic type in such a way that it can be moved for spreading and despreading even during the coiling operation. 
     In accordance with the invention, the direct-drive coiler for winding and/or unwinding rolled strip includes a drum composed of several segments which can be moved so as to be spread and which rest with conically-shaped sliding surfaces against a coiling shaft mounted rotatably cantilevered in a coiler housing, and a plunger guided in the coiler shaft. The plunger is connected through a connecting flange to the drum segments. An axially extending cylinder is mounted in the coiler shaft. The cylinder has a piston which is connected to the plunger and which can effect a relative axial displacement between the coiler shaft and the plunger connected to the segments for producing a spreading movement of the segments. The coiler shaft extends beyond the cylinder with a flanged-on shaft extension which closes the cylinder in the direction toward the axially arranged, directly driving motor. A rotary feed is provided through which pressure medium can be supplied to the piston/cylinder unit provided in the coiler shaft. The rotary feed includes a housing surrounding the coiler shaft and/or the shaft extension, wherein at least one connection each is provided in the housing as a supply line and a discharge line and a bushing is mounted in the housing for each supply line and discharge line. The inner and outer walls of each bushing are equipped with annular ducts which are connected to each other through at least one essentially radially directed bore. The outer annular ducts extend under the supply and discharge connections of the housing and discharge provided for the coiler shaft and/or the haft extension extend under the annular ducts. The rotary feed provides a connection between the piston/cylinder unit and a pressure medium force through which the piston/cylinder unit can be supplied continuously with pressure medium even when the coiler is driven so as to rotate for the purposes of winding or unwinding strip. 
     The rotary feed is to be arranged in such a way that none of the pressure medium lines extends through the shaft of the motor flanged to the coiler shaft or the shaft extension. Accordingly, it is provided to arrange the rotary feed on the shaft extension. However, it is also possible to provide the rotary feed on the coiler shaft itself. By using a double-acting step piston, the necessary spreading and despreading forces can be predetermined in accordance with the corresponding pressure of the pressure medium. 
     Since the rotary feed includes a stationary housing, the external connections to the rotary feed can be arranged so as to be stationary. Flexible hoses which are complicated and susceptible to trouble are not necessary for these connections. The bushings arranged within the housing can be manufactured significantly more easily than if the housing would have the corresponding bushing shape. In addition, by separately providing a housing, the bushings and the sleeve can be realized with different material pairings which ensure that the wear is as little as possible and that they are adapted to each other with respect to their thermal expansion in such a way that the gaps between the bushings and the sleeves have optimum dimensions even in the difficult conditions of rolling mills. 
     The sleeve equipped with the supply ducts can be very easily manufactured. The use of this sleeve makes possible the use of solid shaft extensions which do not have bores, so that a high stability of the shaft extensions is ensured. 
     The pressure medium emerging between the sleeve and the bushings, through which the bushing rests on an oil film on the sleeve, is discharged through leakage oil lines to a tank. The piston/cylinder unit is also provided with leakage oil lines which end in the oil tank. The leakage oil lines of the piston/cylinder unit only conducts oil if seals of the piston/cylinder unit are detected. In that case, leakage oil indicators can be provided which indicate the defect of the seals. 
     In order to ensure that the oil between the sleeve and the bushings is not interrupted during the coiling operation, a predetermined oil pressure level must always be maintained on the pressure medium lines. The pressure medium line “spreading” is then under sufficient pressure, so that a stable oil film is ensured. The pressure medium line “despreading” could theoretically be without pressure during the coiling operation, which, however, would lead to damage of the rotary feed if the oil pressure level were not also maintained on the pressure medium line “despreading”. 
     However, it is also possible to provide additional annular ducts and radial bores in the bushings in order to maintain through the ducts and bores statically an oil film between the sleeve and the corresponding bushing. In that case, the pressure medium lines “despreading” could also remain without pressure during the operation. The oil film has the purpose of absorbing the great weight of the bushings and any acceleration forces which occur at the rolling mill coilers as a consequence of vibrations. A significant advantage of the static oil film results from the elastic expansion of the sealing gap. As a result, defects with respect to shape, for example, deviations from the circular shape, which could occur as a result of the mechanical processing and a change of the natural stress condition under pressure and temperature, are compensated. 
     The outer surface of the sleeve and/or the inner surface of the bushings have ceramic coatings to ensure a longer service life of the sleeve and of the bushings. The resilient support of the bushings in the housing, for example, through O-rings, is advantageous for compensating for symmetric deviations which may occur when manufacturing the individual structural components. The bushings are centered through the oil film on the sleeve and are provided by the O-rings with the possibility of adjusting themselves to the position of the sleeves. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The invention will be explained in more detail with the aid of a drawing. In the drawing: 
     FIG. 1 shows a coiler according to the invention; 
     FIG. 2 is a partial sectional view corresponding to FIG. 1; 
     FIG. 3 shows a piston/cylinder unit according to the invention; 
     FIG. 4 shows a rotary feed according to the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a coiler  1  composed of a drum  2  onto which is wound a coil  3 , a coiler shaft  4 , a shaft extension  5 , a shaft coupling  6  and a motor  7 . A rotary feed  8  is arranged on the shaft extension  5 . The coiler  1  is provided with a push member  10  arranged on a guide  9 ; the push member  10  has the purpose of pushing the coils  3  from the drum  2 . 
     FIG. 2 shows the drum  2  in a partially spread and partially despread position. The drum segments  11  are displaceable on the coiler shaft  4  through a plunger  12  and a connecting flange  13 . The plunger  12  can be driven by a piston/cylinder unit  14  which is connected through pressure medium lines  15 ,  15 ′ to the rotary feed  8 . 
     FIG. 3 shows the piston  16  and the cylinder  17  of the piston/cylinder unit  14  integrated in the coiler shaft  4 . The cylinder  17  is held axially by the shaft extension  5 . The piston  16  is connected through screws  18  to the plunger  12 . The pressure medium lines  15 ,  15 ′, shown arranged one behind the other in FIG. 3, end in the cylinder spaces  19 ,  20 . The piston  16  is sealed in the cylinder  17  through sealing rings  21 . Leakage oil lines  22  have the purpose of collecting any emerging leakage oil quantities and to discharge them to an oil tank, not shown. If oil is conducted in the leakage oil lines  22 , this is a sign that the sealing rings  21  are damaged. 
     FIG. 4 shows the shaft extension  5  on which the rotary feed  8  is arranged. The rotary feed  8  is composed of a housing  23  in which bushings  24 ,  25  are mounted. The bushings  24 ,  25  are mounted on a sleeve  26  which surrounds the shaft extension  5 . 
     Provided on the housing  23  is a connection  27  for the pressure medium for the spreading procedure of the drum  2  as well as a connection  28  for the pressure medium for despreading the drum  2 . In the area in which the connections  27 ,  28  overlap the bushings  24 ,  25 , the bushings  24 ,  25  have annular ducts  29  which are connected to annular ducts  31  through the discharge bores  30 . The annular ducts  31  are located opposite discharge bores  32  in the sleeves  36 . The discharge bores  32  end in the pressure medium lines  15 ,  15 ′. 
     The bushings  24  and  25  are mounted in the housing  23  through O-rings  33 . During operation, an oil film on which the bushing  24  floats is formed between the bushings  24  and sleeve  26 . The oil emerging between the bushing  24  and the sleeve  26  is collected by a leakage oil line and is supplied to the oil tank, not shown. 
     The annular duct  31  of the bushing  25 , which is located opposite the connection  28  for despreading, may be without pressure during the normal coiling operation. If a bushing corresponding to the bushing  24  were to be used for the bushing  25 , a certain pressure would have to prevail during the coiling operation also in the despreading line, so that the lubrication between the bushing and the sleeve  26  is ensured. 
     However, the bushing  25  shown in FIG. 4 has additional annular ducts  34 ,  35 ;  34 ′,  35 ′ and radial bores  36 ;  36 ′ through which a pressure medium for maintaining the sliding film is conducted continuously into the gap between the bushing  25  and the sleeve  26 . The connection  37  has the purpose of conducting the lubricant to the bushing  25  in order to ensure in this manner the hydrostatic support of the bushing  25  on the sleeve  26  without the requirement that pressurized medium must be present at the connection  28 . Of course, a corresponding hydrostatic configuration could also be provided for the bushing  24  or any additional bushings which are not shown. 
     List of Reference Numerals 
       1  Coiler 
       2  Drum 
       3  Coil 
       4  Coiler Shaft 
       5  Shaft Extension 
       6  Shaft Coupling 
       7  Motor 
       8  Rotary Feed 
       9  Guide 
       10  Push Member 
       11  Drum Segments 
       12  Plunger 
       13  Connecting Flange 
       14  Piston/Cylinder Unit 
       15  Pressure Medium Line 
       16  Piston 
       17  Cylinder 
       18  Screw 
       19  Cylinder Space 
       20  Cylinder Space 
       21  Sealing Ring 
       22  Leakage Coil Line 
       23  Housing 
       24  Bushing 
       25  Bushing 
       26  Sleeve 
       27  Connection 
       28  Connection 
       29  Annular Duct 
       30  Radial Bore 
       31  Annular Duct 
       32  Discharge Bore 
       33  O-Ring 
       34  Annular Duct 
       35  Annular Duct 
       36  Radial Bore 
       37  Connection