Apparatus for the continuous winding of a web of sheet-like material, in particular a paper web
BACKGROUND OF THE INVENTION 
     The invention relates to an apparatus for the continuous winding of a web of sheet-like material, in particular a paper web onto a roll core, comprising a carrying drum guiding the web, a transfer device for transferring the empty roll core out of a holding position into an operative position, a drive for the roll core, a support and transport device operative during the winding operation for moving the roll core to discharge the fully wound roll core, and a device for transferring the conveyed web from the fully wound roll core onto an empty roll core. 
     In connection with such an apparatus, a so-called poperoller is known. The continuous winding of a paper web is possible with such a poperoller. In this case, the paper web is guided around a carrying drum and then wound onto a roll core, a so-called tambour. The winding drive is carried out such that the previously mentioned roll core is driven and lies at the outer periphery of the ensuing winding. A swivel arm is arranged approximately concentrically to the carrying drum, by means of which swivel arm an empty roll core can be brought into the winding position when the previous roll core has been fully wound with the paper web. The transfer of the fully wound paper web onto the empty roll core ensues automatically without having to completely interrupt the operation as a whole. The accomplishing of the winding drive via the carrying drum at the periphery of the ensuing winding is associated with certain disadvantages regarding the winding quality. 
     The U.S. Pat. No. 4,744,526 describes a winding apparatus which is also able to work continuously during roll changes, the winding apparatus comprising a carrying drum. 
     A winding apparatus for winding pressure-sensitive paper is known from DE-A-29 35 743 or EP-A-26 335. This winding apparatus makes use of a first pressing roll which is held at a distance from the winding. In the direction of feed of the paper web, a second pressing roll having a soft pressure applying surface is provided behind this first pressing roll. On account of the distance between the first pressing roll and the winding, air is drawn into the winding, particularly at high machine speeds. The drawing-in of this air is prevented by the second pressing roll. Thus, the second pressing roll having a soft surface lies against the surface of the winding under slight pressure. When the winding increases, the position of the second pressing roll is shifted and a switch is actuated which serves to move forward the roll core on which the web is being wound. Thus, a gentle, soft winding without the inclusion of air results. This means that although a good winding quality is provided, the possibility of continuing to wind during roll changes is not provided. For example, no carrying drum is included which is important for the continuous operation for roll changes. 
     Should the continuously operating roller according to U.S. Pat. No. 4,744,526 be combined with the teaching of the application referred to above, a very complicated apparatus would result. 
     In DE-A 1 560 039, a different solution for achieving a uniformly applied pressure is suggested by means of the application of a withdrawal roll and a pressure roll. However, a continued winding during the roll change is also not possible in this case. 
     It is an object of the invention to achieve a soft winding process in connection with the poperoller-system initially mentioned in order to realize a homogenous and gentle winding process across the entire width of the winding. 
     This object is solved in accordance with the present invention in that the carrying drum is arranged as a guiding drum in such a manner that it is always located at a distance from the winding, that a pressing roll is provided behind the guiding drum in the running direction of the web and is arranged in such a manner that it always lies against the winding during operation, that the pressing roll is connected with a sensor for determining the increase in the winding, that the support and transport device for the roll core is connected with a drive controlled by the sensor, and that a separate winding drive is provided for rotating the roll core. 
     SUMMARY OF THE INVENTION 
     The invention consists in that the carrying drum actually used for driving the winding and the carrying axis has been changed in function into a guiding drum in order to feed the paper web guided in the gap between the pressure roll and the winding without air being enclosed in the winding. Thus, the poperoller-system known in itself must only be altered in such a way that a separate winding drive is provided for the roll core and a separate sensor-controlled pressing roll is added which lies gently against the winding, prevents the inclusion of air and enables a gentle winding in connection with the advantageous poperoller system by means of the sensor control and the corresponding transport of the roll core with the winding. 
     According to a preferred embodiment, the surface of the guiding drum has been roughened so that a particularly good guiding action of the carrying drum, changed in function into a guiding drum, is ensured, in fact together with the prevention of axial displacements of the web to be wound. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described in more detail by means of a purely schematic embodiment shown in the drawing. 
     The only FIGURE shows a schematic side view of an apparatus for the continuous, soft winding of a paper web onto a roll core. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A paper web P is fed from the left in the drawing and runs over a guiding drum 12 after first being deflected about a roll 10 and then passes over the winding 14 already recognizable in the drawing. 
     The guiding drum 12 rotates about an axis 16. A swivel arm 20 having a holding fork 22 is pivotably arranged about an axis 18 slightly displaced with respect to the axis 16, as is indicated by the dash-dot circular curve 24. An empty roll core 26 is placed in the fork 22 in order to pivot this out of the position shown in the drawing into an operating position, as explained further below. 
     On the swivel arm 20, a cylinder 28 is arranged with which a supporting arm 30 can be activated in order to hold the roll core 26 in the fork 22 when the swivel arm 20 is pivoted in the manner previously described. 
     Beneath the guiding drum 12, a pressing roll 32 is located which is mounted to a swivel lever 36 by means of an auxiliary lever 34, the swivel lever 36 being pivotable to and fro by means of a cylinder 38. The auxiliary lever 34 is connected to the swivel lever 36 via a swivel axis 40 and has the pressing roll 32 arranged at its one end and acts with its other end together with an inductive transmitter (sensor) 42. The pressing roll 32 is spring-mounted to the auxiliary lever such that the pressure applied onto the winding can be adjusted. 
     Additionally, a horizontally displaceable guiding carriage 44 is provided on the roll core side facing the guiding drum 12, the carriage being driven parallel to both sides via a worm drive 46 and an associated motor 48. A transport lever 52 driven by a cylinder 50 is positioned adjacent to and in cooperation with the carriage. The guiding carriage 44 causes the forward movement of the roll core and the transport lever 52 effects the discharge of the fully wound roll core from the position D into the position E. 
     The transport lever is provided with holding rolls 54 arranged on opposite sides. The carriage 44 has a transport roll 56 lying on the left hand side of the carrying axis as seen in the drawing. The transport lever 52 is pivotable about a swivel axis 58. In other words, the carriage 44 moves horizontally along the worm drive 46 while the associated transport lever 52 and holding rolls 54 pivot on swivel axis 58 to follow the horizontally moving carriage 44, with the holding rolls 54 serving to maintain the roll core 26 upon the carriage 44. 
     The swivel arm 20 is provided with a toothed segment 60 at the lower part thereof, which segment is connected to a pinion drive 62. The roll core lying in the operative position can be rotationally coupled to a separate drive in such a manner that the drive does not ensue at the periphery of the winding. The separate drive in this embodiment comprises a drive member 45 (shown schematically) positioned proximate the guiding carriage 44 in engagement with a side of the roll core 26. It should be understood that any appropriate roll drive known to one skilled in the art can be utilized according to this invention. Finally, a diaphram cylinder 64 is arranged on the swivel lever 36 at the height of the pressure roller 32, the cylinder 64 serving to apply a sensitive, pneumatic pressure against the pressing roll. The surface of the guiding drum 12 is preferably roughened and thus prevents an axial displacement of the web, as the guiding roll 12 serves to exactly feed the web P between the pressure roll 32 and the winding 14. 
     The operating sequence of the depicted apparatus is described briefly as follows. 
     In the started position, the fully wound roll core guided between the guiding carriage 44 and the transport lever 52 lies in the position D. The roll core is still coupled to the winding drive and the pressing roll 32 lies against the winding. The inductive transmitter 42 regulates the actuator 48. The greater the deviation from the desired position, the larger the number of revolutions of the actuator. An empty roll core 26 already lies in the fork 22 of the swivel arm 20 and is ready for a transfer step. 
     When the roll core in the position D is fully wound, the pivoting of the swivel arm 20 is carried out. On account of the slightly eccentric arrangement of the axes 16 and 18, the peripheral surface of the empty roll core ends up on the periphery of the guiding drum 12 and is driven by this. The drive of the wound roll core in the position D is then suppressed such that a loop is blown between the guiding drum 12 and the finished winding 14 and the paper web is separated from one another in this region with the result that the leading end of the paper web P is laid about the empty roll core 26 and wound. The pressing roll 32 is then located in the condition in which it is pivoted away, as depected by dash-dot lines in the FIGURE. The roll core with the winding 14 is decelerated in the position D and the drive is disengaged. The guiding carriage 44 and the winding drive are then moved together from the position D to B and the finished winding is pushed out from D to E by means of the transport lever 52. The transport lever 52 is then pivoted in an empty condition back from E to B. The new roll core pivots to B, driven by means of the contact with the guiding drum. The guiding carriage 44 contacts the roll core 26 together with the winding drive in the position B, the transport lever 52 pressing the roll core against the guiding carriage 44. The winding drive then accelerates to the synchronous number of revolutions and is coupled. Finally, the pressing roll 32 contacts the winding and pivots into the operative position while the roll core is simultaneously transported together with the winding drive by means of the actuator into the position C, which is the initial operative position. 
     If the winding 14 increases with respect to its diameter in the ensuing winding step, then the pressure on the pressing roll increases, resulting in a pivoting of the auxiliary lever 34 and a reaction at the inductive transmitter. In dependence on the actuation of the inductive transmitter, a synchronous drive of the guiding carriage 44 and thus a synchronous, further transport of the winding 14 with the associated roll core 26 results.