Roll Winding Machine

Abstract

An apparatus for winding paper or the like onto two shafts driven by a rotating cylinder which they contact at diametrically opposite locations. The shafts are urged at their ends toward and into contact with the cylinder. Intermediate the ends of each shaft, a pair of rollers rotatably mounted on a frame articulated to a pivot arm urge said shaft toward the cylinder to make certain of uniform contact along the length of the shaft so as to prevent bowing and wrinkling. The pivotal mounting of the arm permits displacement as the package builds up. After the package is large enough so that the paper reinforces the shaft and itself ensures uniform contact without bowing, the pivot arm is moved to inoperative position where the rollers no longer act on the shaft.

Description

The invention relates to a method and apparatus for winding material in web form, such as paper or the like, by means of two winding shafts located on diametrically opposite sides of a supporting cylinder.

For technically satisfactory further processing of a web of material following slitting of a wide roll into narrower rolls and winding of the individual narrower rolls, it is necessary that all of the rolls wound in a winding procedure have a uniform firmness over their entire working width so as to prevent wrinkling, tearing and other such damage to the web of material which would result from differences in roll hardness or firmness when they are cut to width.

Processes of this kind have become known in which the danger exists that the wound rolls are more or less collapsed and deformed depending on the diameter and on the width of the rolls. This deviation from the desired cylindrical shape of the wound roll is produced as follows: on the one hand a contact pressure acts in the plane determined by the supporting cylinder axis and the wound roll axis and develops at the line of contact between the two rotating bodies. On the other hand, the weight of the wound roll itself produces a sag in it which, combined with the deformation due to the contact pressure, forms an angle, which results in a change in the shape of the wound roll, the new shape being composed of two planes. The undesirable bending or sagging is caused by the fact that the wound roll is supported at the ends of its shaft i.e., there are no intermediate supporting means and thus the roll is wound substantially without any support from below. In order to exert an influence on the firmness of the roll, a force acting in the direction of the supporting cylinder is applied to the end supports of the roll being wound, thereby urging the roll against this cylinder, and in this manner it is supposed to be subjected to a uniform linear pressure. Since the roll being wound is still very flexible in its initial stages, however, the axial pressure cannot be distributed uniformly over the entire width of the roll being wound, so that the terminal portions of the roll are subjected to greater pressure than its central portion. This results in a deformation or bowing of the roll under the contact pressure corresponding to the line of curvature of a cylinder being stressed at each end with a point load.

The consequence of this is that the terminal portions or ends are wound substantially more firmly than the rest of the roll, resulting in the formation of wrinkles and creases, and also in an undesirable difference in the final diameter along the width of the roll.

The invention is addressed to the problem of winding rolls having a uniform tightness all along their width.

This problem is solved by the invention in that the roll being wound is provided in its initial stage with such inherent stability that the winding process can thereafter be completed without auxiliary supporting means while achieving a uniform tightness. The winding process, which is started under simultaneous, radially directed pressure at the ends of the winding shaft as well as intermediate the ends, is completed under complete freedom of pressure intermediate the shaft ends after a certain roll diameter has been reached, and the remaining axial pressure on the ends of the shaft of the roll being wound is varied in accordance with its diameter. To this end, a pair of pressure rollers which supply the intermediate radial pressure on the circumference of the roll being wound are disposed on the free end of a lever which is itself mounted so as to be displaceable to inoperative position where it does not affect the movement of the roll. The pivot point of the lever is located in such a manner that the force vectors of the individual pressure rollers intersect one another throughout the winding process in a plane determined by the supporting cylinder axis and the axis of the roll being wound.

Thus, only during the initial stage of winding onto the inherently flexible core is an additional temporary pressure applied, using a pair of pressure rollers, until the unit of core plus material wound thereon reaches a predetermined diameter at which the unit has achieved sufficient inherent rigidity so that winding can continue even without the additional pressure from the roller pair and nonetheless the material will continue to be wound with uniform tightness across the width of the roll. The contact pressure delivered through the points at which the roll being wound is supported, in the direction of the supporting cylinder, can then be uniformly distributed by the roll itself and can be effective without the use of additional means. Even the sagging caused by the weight of the roll being wound can then be kept within limits by the tightly wound roll core even though no supporting means is provided to compensate for this weight.

Another advantage of the tighter core winding becomes apparent when the rolls are transported and when they are further processed in the various machines that follow. This is because the cores preserve their shape, inasmuch as they cannot be collapsed so easily by shock stresses, and because the braking torque that is to be applied to the roll as it is unwound is more reliably transmitted to the point where the material leaves the roll.

The invention will be further described with reference to the accompanying drawings wherein:

FIG. 1 is a side elevational view of a roll cutting and winding machine as the winding cycle begins;

FIG. 2 is the same view of the machine after the wound packages have reached a predetermined size and the pivot arms have swung away;

FIG. 3 shows the pair of pressure rollers on a larger scale; and

FIG. 4 shows the manner of operation of the pair of pressure rollers.

Referring now more particularly to the drawings, in FIG. 1 a web of material 1 is drawn from a supply roll 2 and fed over guide rolls 3, 4 and 5 through a longitudinal slitting means consisting of bottom knife 6 and top knife 7, to a driving support cylinder 8 from which one of the longitudinal divisions of the web is delivered to winding station 9 and the other is delivered to winding station 10. Winding cores 11 and 12, each of which respectively receives the strips 1' and 1" of the slit web 1'", are received in carriages 13 and 14, respectively, and urged against the supporting cylinder 8 by a conventional lever system (not shown). Pairs of pressure rollers 19--19 and 20--20 mounted respectively at points 15 and 16 on pivot arms or levers 17 and 18 ride on the circumference of the wound packages 21 and 22 that are being formed, thus preventing any possible deflection of the packages 21 and 22 that might be caused by the axial pressure transmitted by the carriages 13 and 14 on the ends of the shafts or cores.

To prevent geometrical misalignment, and hence any misalignment of forces at the cores 21 and 22, such as might arise out of the cooperation of the straight guiding means 29 and 30 with the pivoting movement of the arms 17 and 18, the pairs of pressure rollers 19--19 and 20--20 on the arms 17 and 18 must be articulately mounted. However, their freedom of movement is limited by pin 33 (FIG. 3) affixed to each of the levers 17 and 18, which extends into a slot 34 of pressure roller mounting plate 35. The reason for this limitation is that, in the event of an undesirable deflection of the core 21 or 22 in an indeterminate direction, the pair of pressure rollers 19--19 or 20--20 would follow the deflection if the range of movement of the mounting plate 35 were too great, and thus they would not provide the kind of support they were intended to provide.

To enable the pairs of pressure rollers 19--19 and 20--20 always to bear against the winding core at their most effective point, i.e., toward the axes of the winding cores 11 and 12, the corresponding pivot arms 17 and 18 are suspended in a pivotally displaceable manner about round guiding means 23 and 24.

The arrangement of the pivot arms or levers 17 and 18 is such that the pairs of pressure rollers 19--19 and 20--20 are able to follow the constantly growing diameter of the wound packages 25-26 within their range of action, with both pressure rollers bearing constantly against the circumference of the packages being wound. After the package being wound has achieved a sufficiently great stiffness of its own, the arms 17 and 18 with pressure roller pairs 19--19 and 20--20 are swung up out of range about the round guiding means 23 and 24 which serve as their pivot point or fulcrum (by means of the phantom structure in FIGS. 1 and 2). Rolls 25 and 26 then continue to be wound and are urged against the supporting cylinder 8 with an axial pressure that is constantly diminished by means of levers (not shown) as their diameter increases, until the final diameters 27 and 28 are achieved and the carriages 13 and 14 are in their outermost position on the guiding means 29 and 30. After the removal of the finished rolls 31 and 32 (shown in phantom in FIG. 2) and the installation of fresh winding cores 11 and 12, the next winding cycle can be performed in the same manner.

It will be appreciated that the instant specification and examples are set forth by way of illustration and not limitation, and that various modifications and changes may be made without departing from the spirit and scope of the present invention.

Claims

What is claimed is:

1. In an apparatus for winding of material in web form including a pair of winding shafts for receiving respective material to be wound thereon, a supporting cylinder contacting and driving said shafts, said shafts being diametrically opposite one another about said cylinder, and means urging the axes of said shafts adjacent their ends radially toward said cylinder, the improvement which comprises a pair of spaced pressure rollers urging each of said shafts intermediate its ends radially toward said cylinder, a pivot arm for each of said intermediate urging means, means coupling said intermediate urging means to said pivot arm, whereby as said material is wound upon each shaft and the diameter of said shaft and material thereon increases said intermediate urging means and pivot arm are pivotally displaced while still urging said shaft intermediate its ends, and means for displacing each of said pivot arms with its associated intermediate urging means to inoperative position wherein said intermediate urging no longer operates upon said shaft while material continues to be wound on said shaft, whereby the intermediate urging means may be rendered inoperative after said shaft has become stabilized due to receipt thereon of a predetermined amount of material.

2. An apparatus according to claim 1, wherein said means coupling the pair of pressure rollers constituting said intermediate urging means to said pivot arm comprises an articulated linkage.

3. An apparatus according to claim 2, wherein the pivot point of said articulated linkage is so located that when each pivot arm is in operative position the radial force vectors of said two pressure rollers on said shaft always intersect one another throughout winding in the plane defined by the axis of said cylinder and of said shaft.

4. In the winding of material in web form onto two shafts driven by a common supporting cylinder wherein the ends of each shafts are urged radially toward said cylinder to force said shaft against said cylinder, the improvement which comprises displaceably urging each shaft against said cylinder at a location intermediate the shaft ends, whereby said intermediate urging can be maintained as the material is wound onto the shaft, discontinuing said intermediate urging after a sufficient amount of material has been wound onto the shaft so that it will uniformly contact said cylinder even without said intermediate urging, and thereafter continuing winding under the influence of said urging of the ends of said shaft to complete winding of the material.

5. Process according to claim 4, wherein said intermediate urging is effected along a pair of parallel lines spaced from one another about the circumference of said shaft, the force vectors along the two lines always intersecting one another in the plane defined by the axis of said cylinder and said shaft.