Abstract:
Apparatus for winding a web section without using a core, the web section including a plurality of transversely extending perforation lines and wherein a torn web section is removed from a continuously supplied web. The apparatus includes two winding stations that are diametrically opposed on opposite sides of rotatable, circular carrying discs. Each of the winding stations includes a pair of opposed winding heads, and the winding heads each includes a pair of winding pins that extend in the direction of the winding aixs. The pins are rotatably mounted for rotation as a pair about the winding axis and are connected to a rotary drive. The winding pins are also extendable to a winding position and are retractable to a non-winding position. When in the winding position the pins extend outwardly from the winding head and are spaced from each other a distance sufficient to receive a web therebetween, and upon rotation of the winding heads the web is wound into a roll without the need for a core.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to apparatus for winding up a web section without using a core, and in which the web section has been torn along a transverse perforation line from a web which is continuously supplied and provided with spaced transverse perforation lines. 
     2. Description of the Prior Art 
     In winding apparatus of the type disclosed in West German Patent Publication No. 21 27 128, winding pins, which in the winding position protrude freely over the width of the web, are secured to the free ends of levers, which are pivoted in a winding head and are held, e.g., by springs, in their inner, retracted position. The winding pins can be pivotally moved to their spread position by an axially displaceable mandrel, which has a conical end portion that engages corresponding cam faces of the level. That apparatus has a relatively expensive structure because the protruding winding pins must be extended and retracted substantially throughout the width of the web which is to be wound up, and as they are extended the pins must be be spread relative to each other to such an extent that the web can move freely between the winding pins to the other winding station. 
     West German Utility Model Specification No. 77 12 942 discloses winding heads which are provided with winding pins, which in their non-spread position are sufficiently spaced apart to permit the web to move between the winding pins. but the winding pins must protrude freely over a large length beyond the web to be wound so that they can be bent outwardly to their spread position by a spreading cone. 
     Swiss Patent Specification 487,791 discloses a winding apparatus having a winding station which is fixed to the frame and includes two mutually opposite pairs of winding pins, which are connected to rotary drive means and are adapted to be advanced toward a web that is to be divided into sections that are to be wound up without using a core. The two winding pins hold the web therebetween and are retractable from the side edges of the web when a roll is to be released. That apparatus serves for intermittent winding of web sections which have been severed from a continuous web. The winding pins are displaceable in a common plane toward and away from each other, and as they are advanced they move like tongs to grip the web. As they are retracted they perform a corresponding closing movement to reduce the frictional coupling between the winding pins and the roll, which can then easily be stripped from the winding pins. The roll, which is still connected to the web, then falls into a receiving tub. The means for severing the web from the roll includes pairs of gripping jaws disposed on opposite sides of the winding station, and a cutting knife is disposed between the pairs of jaws. Before the web which is gripped by the jaws is severed, the web is tensioned by a tensioning device so that the properly aligned and spread winding pins can be advanced toward each other in order to engage the web. That winding apparatus does not permit a winding up and severing of a continuously supplied web. The web must be stopped for the severing of each roll consisting of a web section having a predetermined length, and it must be gripped by separate gripping means on both sides of the winding station and must be severed by a separate cutting device. As a result, the winding rate is restricted and the structural expenditure is increased. 
     It is an object of the present invention to provide web winding apparatus and in which the winding of the web sections to form supply rolls requires smaller axial displacements and smaller radial spreading movements of the winding pins. 
     SUMMARY OF THE INVENTION 
     Briefly stated, in accordance with one aspect of the present invention, apparatus is provided for winding up without using a core a web section that has been torn along a transverse perforation line from a web that is continuously supplied and provided with longitudinally spaced transversely extending perforation lines. The apparatus includes a frame, and a pair of winding stations each including a pair of aligned and opposed winding heads defining a winding axis and spaced transversely from each other relative to the web movement direction. The winding heads each carry a pair of rotatably mounted winding pins that are movable within an associated winding head along the winding axis from an extended position to a retracted position relative the winding head. Rotary drive means are provided for rotating pairs of the winding heads and the winding pins about the winding axis. The winding pins protrude freely from the winding heads when they are in the extended position and are spread outwardly relative to each other, and are retractable to a non-spread position wherein the web extends between the winding pins of one winding station when the web is wound up on the other winding station, and wherein when the web is to be taken over by the other winding station, the winding pins of that other winding station are extended from their retracted position to their extended position in which they hold the web therebetween. The winding pins are spaced from each other on opposite sides of the winding axis at a distance sufficient to permit the web to move freely between the winding pins, and the pins are movable relative to each other in spaced parallel planes from a spread position to a non-spread position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevation showing winding apparatus in accordance with the present invention and including two winding stations. 
     FIG. 2 is a front elevational view showing the winding apparatus of FIG. 1. 
     FIG. 3 is an enlarged, fragmentary cross-sectional view showing a winding head of one winding station. 
     FIG. 4 is a fragmentary cross-sectional view taken on line IV--IV in FIG. 3 and showing the piston rod and the holder associated with one winding head. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, and particularly to FIGS. 1 and 2 thereof, there is shown a machine frame 1a that includes a pair of parallel, spaced side walls 1, 2, that are interconnected by a pair of parallel guide bars 3. A pair of sleeves 4a, 5a are slidably carried on the guide bars, which define a pair of tracks between side walls 1 and 2, and sleeves 4a, 5a, support annular carrying rings 4, 5, respectively, for movement along the guide bars and between the side walls of the frame. Rings 4 and 5 each define circular openings, the purposes of which will hereinafter be described in greater detail. Also carried by sleeves 4a and 5a are nuts 6 and 7, respectively, that have internal threads that are engageable with the external threads of a screw 8 that extends between side walls 1 and 2 in a direction parallel to the axis of guide bar 3. The external threads on screw 8 are of opposite hand on respective halves of the screws, so that upon rotation of screw 8 each of nuts 6 and 7, and also sleeves 4a and 5a, can be moved toward and away from each other in the directions indicated in FIG. 2 by the double headed arrows about screw 8. A handwheel 9 is provided on one end of screw 8, and the screw is rotatably carried and is axially fixed in the side walls 1 and 2. 
     Carrying rings 4 and 5 are of similar construction, and the ensuing description will be based upon carrying ring 5 and its associated structural components, and it is to be understood that the description applies with equal effect to carrying ring 4 and its associated structural components. Carrying ring 5 includes an inner circular rim portion 10 that engages with peripheral grooves of a plurality of rollers 12, four of which are shown in phantom in FIG. 1, for circular movement around the axis of rim portion 11. A circular disc 13 is provided adjacent to carrying ring 5 and includes external teeth 15 that are engageable with an output pinion 81 of a motor 80, rotation of which serves to rotate disc 13. Rollers 12 are each rotatably carried by circular disc 13 and serve to support disc 13 for circular movement about the central axis of rim portion 11. Spaced opposite from and facing circular disc 13 is a second circular disc 14 that is parallel to disc 13 and also carries a plurality of rollers 12, which engage with inner rim portion 10 of carrying ring 4, in the same manner as in the corresponding structure hereinabove described in connection with circular disc 13. 
     Each of discs 13 and 14 carries a winding head 16, 17, which because they are identical except for their orientation relative to each other, will be described in terms of the structure of winding head 16, and it will be understood that winding head 17, as well as winding heads 18 and 19 that are spaced diagonally opposite from winding heads 16 and 17 on discs 13 and 14. have the same structure and functions as winding head 16. winding heads 16 and 17 lie on one winding axis and winding heads 18 and 19 lie on a second winding axis. 
     Referring now to FIG. 3, which shows a fragmentary portion of circular disc 13, a bore 13a in disc 13 carries a bearing ring 20 that includes an outwardly extending flange 20a that engages one face of circular disc 13. A pair of rolling element bearings 21a, 21b, are carried within bearing ring 20 in axially spaced relationship. The outer races of the bearings engage with and rotate with bearing ring 20, and the inner races engage with and rotate with a bushing 21 that includes an outwardly extending annular flange 21c that faces circular disc 14. Bushing 21 carries a pulley 22 that is keyed thereto in order to rotate therewith, and a toothed belt 22a passes around pulley 22 to rotatably drive bushing 21 about a winding axis that passes through the center of bushing 21. 
     Positioned within bushing 21 is a pair of winding pins 23, 24, which are substantially flat, elongated strips of metal that are disposed in scissor-like relationship. Each of winding pins 23, 24, is the longer arm of one of a pair of bell-crank levers that include shorter arms 28 and 27, respectively. The bell-crank levers are pivotable about a common pivot 25 which extends transversely of the winding axis and is carried by a holder 26. The outer ends of shorter arms 28 and 27 carry rollers 29 and 30, respectively, which bear against the outer end face 31 of pulley 22 and move in a radial direction relative to the winding axis. 
     Winding pins 23 and 24 each have ends that extend outwardly beyond flange 21c of bushing 21, and are held in position relative to each other by means of a plate 45 that includes a pair of spaced, parallel slots to receive respective winding pins 23 and 24. The slots have a length greater than the width of the winding pins to permit the pins to move in scissor-like relationship, while they are spaced a predetermined distance from each other and move in parallel planes from an extended position wherein the winding pins are in an opened position relative to each other and extend outwardly beyond plate 45, to a retracted position wherein they are in a closed scissor position and in substantially opposed relationship and are partially retracted into bushing 21. Plate 45 is held in position by a plurality of bolts 42a, 43a which are received in threaded holes in flange 21c. A pair of abutments 42, 43, are also held in position by bolts 42a and 43a, respectively, and are on diametrically opposite sides of the winding axis. Each of abutments 42 and 43 receives one end of a compression spring 41, 40, respectively, the innermost ends of which springs bear against pressure applying members 38, 39, respectively, that, in turn, engage the outermost edges of winding pins 23 and 24, respectively. The springs urge the pressure applying members against the winding pins to move them to the clsoed, overlapped position. 
     Holder 26 is rotatably carried in an axial bore 34 of a piston rod 35 by means of a rolling element bearing 33. As best seen in FIG. 2, piston rod 35 extends from a pneumatic cylinder 36. Cylinder 36 is secured to circular disc 13 by means of a flange plate 36a that is connected to disc 13 by means of a plurality of studs (not shown) that have axes that are parallel to the axis of cylinder 36 and piston rod 35. Thus the axial extension and retraction of piston rod 35 causes corresponding axial movement along the winding axis of holder 26, and also of winding pins 23 and 24. Further, because of the rotatable mounting between holder 26 and piston rod 35, holder 26 rotates together with bushing 21 about the winding axis. 
     As best seen in FIG. 3, holder 26 includes a forked end portion 26a between which the winding pins 23 and 24 are carried in pivotable relationship about pivot 25, and also includes radially extending arms 50 and 51, which are offset 180° from each other about the axis of rotation of holder 26. As shown in FIGS. 3 and 4, positioned about piston rod 35, and in concentric relationship therewith, is a sleeve 54 that includes a pair of cam tracks 52, 53, formed by two substantially elliptically curved surfaces that each extend symmetrically from a top apex 55 in a direction away from disc 13. When one of radial arms 50 or 51 contacts one of cam tracks 52 or 53, as piston rod 35 is retracted into cylinder 36 and away from winding head 16, the end of the radial arm will slide along the cam track portion, and will thereby rotate holder 26 about the winding axis until the opposite arm has engaged the opposite portion of the cam track. In that position, continued retracting movement is prevented, and winding pins 23 and 24 and then so aligned relative to the direction of movement of the web to permit the web to pass between the winding pins, which are spaced from each other, so that the web is passed between the opposed faces of the winding pins as they are advanced once again by piston rod 35 of pneumatic cylinder 36 to an extended position relative to plate 45. The relative orientation of piston rod 35, sleeve 54, cam track 53, apex 55, and radially extending arms 50 and 51 is shown in perspective in FIG. 4 of the drawings. 
     Referring once again to FIGS. 1 and 2, each of discs 13 and 14 carries two pairs of opposed winding heads 16, 17, and 18, 19. The winding heads are driven by a motor 60, that is supported on the inner surface of side wall 2 and from which a disc pulley 60a extends. A cogged drive belt 61 extends around pulley 60a and also around a driven pulley 62a that is secured to a central splined shaft 62 that is rotatably carried in side walls 1 and 2 and is substantially centrally positioned relative to the rim portion 11 of annular ring 5. A hub 63 is carried on splined shaft 62 and, in turn, carries a clutch-brake combination 65 that includes a pulley 67. A drive belt 67a passes around pulley 67 and also around pulley 72a that is carried by hub 72, which, in turn, is slidably carried on intermediate splined shaft 70 for rotation therewith. Shaft 70 is spaced from and parallel to central splined shaft 62. Hub 72 is carried in circular disc 13 and also rotatably carries pulley 72b, which rotates with pulley 72a and about which belt 22 passes to interconnect pulley 72b with pulley 22 of winding head 16. 
     Clutch-brake combination 65 is of known construction familiar to those skilled in the art, and can be operated electrically, such as by slip rings 77. The purpose of clutch-brake combination 65 is to selectively transmit driving torque to the winding head and to restrain the winding head from rotation relative to disc 13. 
     Pneumatic cylinders 36 are operated from a source of compressed air (not shown) that can be supplied through lines that extend from cylinder 36 to central splined shaft 62 by means of a rotary connection, similar to a slip ring, or the like. 
     In operation, web 46, shown in FIG. 1, passes around a guide roll 85 to a winding station defined by winding heads 16 and 17, which are positioned as shown in FIG. 2. The web also extends between the spaced winding pins of winding heads 18 and 19. 
     The web passes about an element 86 located between winding stations. When a sufficiently long web section having a predetermined length and including a predetermined number of articles, such as, for example, garbage bags, which are separated by transversely extending perforation lines, has been wound up on winding heads 16 and 17, the clutch-brake combinations 65 and 66 are actuated so that the winding heads 16 and 17 are stopped and the winding heads 18 and 19 are started. As the latter are started, the web is torn along a transverse perforation line which is disposed between the two winding stations. As a result, the winding pins in the completed roll of articles can be retracted so that the roll can be removed and the next following roll can be wound in the other winding station. 
     As a roll is being wound, the circular discs 13 and 14 are rotated together to change the locations of the respective winding stations so that winding heads 16 and 17 can be moved to the lower position shown in FIGS. 1 and 2. Those winding pins that have been retracted during the shifting of the winding stations are subsequently re-extended to be disposed on opposite sides of the web 46, and are then ready to start the next succeeding winding cycle. 
     Although particular embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit of the present invention. It is therefore intended to encompass in the appended claims all such changes and modifications that fall within the scope of the present invention.