Abstract:
At the end of a paper processing machine, a layer stack formed there is gripped by a gripper (16) and is delivered through a shorter linear movement either to a first transverse conveyor (24), or through a longer linear movement to a subsequent second transverse conveyor (25). Thus, during discharge with the particular transverse conveyor (24, 25), the other transverse conveyor (25, 24) can be loaded with a single or several sheet stacks. for overtravelling the first transverse conveyor (24) with a sheet stack, a moving bridge (20) is provided having bridge parts (44, 45), which project toward each other and are movable, and whereof one bridge part (45) simultaneously forms a support arm (64) for supporting the layer unit prior to deposition on the second transverse conveyor (25). This construction permits a very high discharge capacity and simultaneously varyingly high stacks can be collected and conveyed away.

Description:
This is a continuation of application Ser. No. 07/729,043, filed Jul. 12, 1991, now abandoned. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to a conveyor means for layer units, particularly flat sheet layers, which singly or multiply rest flush on one another and which are conveyed, brought together or supplied to further treatment processes in the form of layer stacks. 
     BACKGROUND OF THE INVENTION 
     During paper processing, a plurality of superimposed paper webs can be initially subdivided with longitudinal cutters into several size-maintaining useful widths and can then be subdivided by means of a cross cutter into individual, juxtaposed sheet layers, and optionally, can be supplied to further operating stations and finally stacked in juxtaposed manner to form layer stacks, which normally have roughly 500 individual layers and which are referred to as reams. These juxtaposed layer stacks, over the width of the paper webs, are then transferred by a delivery means to the transfer station of a transverse conveyor and discharged to a packing machine or the like. 
     In the case of DE-OS 32 20 095, the layer stacks are gripped by a gripper conveyor at the front end in the delivery direction, are drawn on to a lowerable lifting table, optionally stacked to form larger overall stacks, and are then conveyed away, which permits faster working. However, it has been found that the working speed of the supplying paper processing machine can be further increased, so that there is a need for a corresponding capacity rise of the associated conveyor means. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a conveyor means of the aforementioned type, which avoids the disadvantages of known constructions and which in particular permits a further increase of the working speed and different further treatments to the transferred layer stack in simple manner. 
     According to the invention, this object is achieved in that means are provided for conveying at least one layer unit from optionally juxtaposed, incoming layer units to at least one associated transfer station and over and beyond the same, independently of whether the transfer station is or is not already occupied by one or more layer stacks. This transfer station to be bypassed is usually that which is first reached by the layer stack in the delivery direction. Therefore, the particular layer stack can be either deposited by means of the delivery means in the transfer station or can be conveyed beyond the same for a different use, e.g., into a further transfer station where deposition takes place. Thus, it has been found that the working cycle time of a discharging means, particularly for layer stacks, cannot be increased in the same way as the cycle time for the supplying process machine and the delivery means because excessively high discharging speeds create a tendency for the upper individual layers to be raised by the airflow or the like or for layer stacks to become askew due to excessive accelerations. This disadvantage also occurs if two transverse conveyors lead away from one longitudinal conveyor in such a way that the second transfer station in the longitudinal conveyor direction can only be occupied with a layer stack if the first transfer station is free. In this case, successive layer stacks in the longitudinal conveying direction are successively pairwise brought into the vicinity of the transverse conveyors and then transversely conveyed away. 
     According to the invention, only the furthest forward or the juxtaposed furthest forward individual stacks are taken over by the delivery means and conveyed towards the transfer station. In order to be able to obviate complicated construction of the conveyor means, the delivery means does not drive the layer stack in the same way as a belt conveyor or the like through a movable running path. Instead, the drive is formed by conveying means separate from the optionally stationary running path, which acts on the layer unit substantially over the height thereof and preferably is at least partly located above the running path. 
     So as to ensure that, when bypassing the transfer station with the layer unit, at the most insignificantly increased bypassing distances have to be covered, the layer stack is appropriately moved beyond or through the particular transfer station. Thus, the delivery means can perform an optionally reversing linear movement, which is preferably linear in one or both opposite directions, which permits a very simple construction. For this purpose, two or more transfer stations are arranged successively in substantially aligned manner in the delivery means direction, so that the supplied layer unit can be deposited in each random transfer station. For bypassing purposes, the layer unit does not have to be guided on a bypassing arc either in the height direction, or in the lateral direction. Bypassing is particularly simple if, in the direction of the discharging means, successive transfer stations are interconnected by means of substantially linear, planar or horizontal running paths for the layer units. Bypassing is also simple if the support for the transfer station is raisable or lowerable during the operation by means of a control mechanism by an amount which is at least as large than the height of the particular layer unit. Thus, the transfer station can form a height-adjustable depositing shaft with a fixed top, over which it is easy to travel. 
     According to a particularly advantageous further development, a moving bridge is movable on or over the top of the transfer station or the layer unit located therein, and the layer unit can run on it to pass over said transfer station. The moving bridge can cover the transfer station in the overtravel position either completely or only partly, in grating or grid-like manner, and the bridge appropriately is continuously connected to at least one of the boundaries of the transfer station at right angles to the delivery means direction. The moving bridge keeps the support below it or the layer unit above it separated from the overtravelling layer unit. 
     For the movement of at least one part of the moving bridge between its overtravelling position and a normal position that frees the transfer station, it is necessary to provide a movement direction approximately parallel to a movement direction at right angle to the delivery means direction. If the bridge part extends from the transfer station side first reached by the layer unit in the delivery means direction, it can be moved by corresponding control means roughly synchronously with the layer unit located thereon in the direction of the delivery means, so as to-ensure a very carefully handling of the layer unit. 
     Simultaneously, prior to being reached by the overtravelling layer unit, a bridge part can also be extended from the opposite side. The moving bridge, or at least part thereof, consequently does not have to be moved over the entire associated extension of the transfer station, and instead, this need only take place over a portion thereof. 
     Particularly if successive, adjacent transfer stations have a relatively small distance from one another, and this distance is e.g. only roughly the same as the associated extension of a transfer station or smaller, the moving bridge or a part thereof can be slid over each of these two adjacent transfer stations. 
     If at least one or all the transfer stations of a delivery line are constructed as collecting stations for the superimposed stacking of successively delivered layer units, whereof at least one has a support, which is raisable and lowerable independently of at least one further transfer station, then numerous different operations are possible and e.g. successive transfer stations can be alternately supplied with layer units. 
     In addition, in a transfer station closer to the start of the delivery means and/or a following station can be used for the formation of individual layers to give higher overall stacks with e.g. 2500 sheets or more. However, it is also possible to deposit in a transfer station a single layer unit, which is then conveyed away, while in a further and in particular a following transfer station layer units are stacked and which are then conveyed away. 
     An alternating, differently high loading of successive transfer stations is also possible. Despite the further working of the delivery means, in each case, the time available for discharging from a transfer station is that which is required for the loading of a further transfer station with at least one layer unit. It has been found that in this way the output of the processing machine, which every six seconds provides a row of juxtaposed layer units at right angles to the delivery direction and which must be taken over at the start of the delivery means, can be handled without intermediate storage means, because the conveyor with the alternately inoperative and conveying transfer stations forms such a storage means. If the intermediate storage means was only formed by two raisable and lowerable, superimposed supports in the vicinity of said transfer station, during the discharge of the lower stack, at least one further layer unit could be placed above this lower stack, but then the upper support would have to be drawn out again substantially over the entire length of the layer unit secured by grippers, which can lead to displacements between the individual layers during stacking. In addition, such a construction would usually be relatively complicated and in connection with the supporting of large widths would lead to problems. The described alternating operation would only be possible with difficulty and a greater overall height would result. 
     Instead of, or in addition to, the described construction, the set object can also be achieved in that means are provided with which the supplied layer unit can be supported on the underside up to the precise alignment with respect to the transfer station or a layer unit already located therein. These means are appropriately constructed in such a way that, following the delivery of each individual layer unit, they are immediately retracted and several layer units are not superimposed stacked thereon. They are substantially synchronously controlled with the cycle of the delivery means when the latter is depositing in the associated transfer station. 
     Instead of constructing the support means in such a way that it supports the layer unit to be taken over on its entire underside, there is preferably an arrangement in which the layer unit, at least towards the end of the alignment with respect to the transfer station, is only supported on two facing marginal areas and is not supported between them. A marginal area gripped in pulling manner by a clamp can be narrower than the facing marginal region only supported on the underside and whose width is only half the associated longitudinal extension or smaller. The superimposed individual layers of the layer unit are consequently securely held in their flush position, being moved in contact-free manner over the support of the transfer station and then, after retracting the support that only acts on the underside of the layer unit, firstly said associated marginal area is deposited on the support. Only then is the gripper or clamp opened and retracted in the opposite direction, so that also this marginal area is deposited. 
     If the support acting on the stack underside is substantially in one piece in thin plate-like manner and free from belts, rollers, etc. over its thickness, then it can have a thickness of only a few millimeters. In addition, in the support position, it can be supported in freely projecting manner on the top of the support or the top layer unit, without having to be supported in its lateral area up to its front end with respect to the frame. It can also be kept substantially contact free with respect to the support or the top of the already transferred layer unit by a gap. 
     The means for the sliding overtravelling of a transfer station can form the means for the sliding support of a following transfer station and consequently alternately act with one end as a moving bridge and with the other end as a support bridge or an upper shield for the deposited layer units. 
     In accordance with the inventive method, layer units are successively delivered to separate transfer stations or separately conveyed away by the latter. These working sequences can be so interlinked that alternately one transfer station is loaded and the other unloaded. The delivery takes place in a conveying plane, which is defined by the underside of the layer unit during delivery. The transfer takes place in a bearing plane, which is defined by the underside of the layer unit after transfer and is formed by the bearing plane of the transfer station or the top of a layer unit already located on the bearing plane. When the transfer station is not occupied, during the overtravelling with a layer unit, its bearing plane can be roughly located in the conveying plane. However, if said bearing plane is formed by the conveyor belt of a transverse conveyor, it is appropriately slightly lowered, so that it will not or will only slightly be in contact with the overtravelling layer unit. This also applies in the case that an already transfer red layer unit is overtravelled. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features can be gathered from the claims, description and drawings. Embodiments of the invention are described hereinafter relative to the drawings, wherein show: 
     FIG. 1 An inventive conveyor means on a processing machine. 
     FIG. 2 The conveyor means in longitudinal section. 
     FIG. 3 Part of the conveyor means in cross-section. 
     FIGS. 4 to 6 Further embodiments of the conveyor means in plan view. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The conveyor means 1 is positioned at the end of a paper processing machine 2, which is supplied from paper rolls of a web supply means 3 with successive paper webs. A longitudinal cutter 4 of the processing machine 2 cuts the paper webs in waste-free manner into size-maintaining longitudinal strips, which are then subdivided by a cross cutter 5 into juxtaposed partial stacks. Further stations 6, which are used e.g. for discharging faulty layers, the overlapping of successive layers and the stacking of partial layers to form layer units are successively traversed by the layers. At the end of these stations, in each case, a row of juxtaposed layer units reaches the discharge station of the processing machine, where they are taken over by the conveyor means 1. 
     Referring to FIG. 2, the takeover takes place by a delivery means 8, which appropriately transfers all the juxtaposed layer units simultaneously and synchronously continuing the movement direction of the processing, machine 2 to the transfer stations 9, 10, which are positioned successively in this direction and in each case have a plurality of juxtaposed transfer points corresponding to the number of juxtaposed layer units. From the transfer stations 9, 10, the layer units are conveyed independently of one another via discharging means 11, 12, e.g. to separate packing means. The juxtaposed layer units simultaneously located in the particular transfer station 9 or 10 can be conveyed away together or individually or in groups in the same or opposite directions. 
     For the taking over of the furthest forward layer unit from the discharge station 7 a conveyor 13 is provided, which simultaneously engages all the juxtaposed layer units of a cross cut row then conveys them towards the first transfer station 9 and does not take over the layer units individually or in groups with independently movable individual conveyors. The conveyor 13 has a guide located above the transfer stations 9, 10 as well as a drive 15, which e.g. by means of a toothed belt drive moves juxtaposed grippers for the layer units in reciprocating linear manner along the guide 14. All the pneumatically operated grippers 16 can be located on a common base or pedestal 17, which is pivotably mounted with respect to a travelling carriage mounted on the guide 14 and about a shaft roughly parallel to the conveying plane and roughly at right angles to the conveying direction above the grippers 16. On moving in the conveying direction and if the gripper 16 encounters an excessive resistance, the base 17 is freed counter to the force or tension of a locking overload protection and is released in upwardly pivoting manner about the pivot shaft 18 counter to the conveying direction and a contact, operated as a result of this, stops the conveyor means. The drive 15 is provided with a torque-dependently operating overload protection, which disengages if, on moving counter to the conveying direction, the grippers 16 encounter an excessive resistance. The base 17 hung on the pivot shaft 18 can be supported with an underlying rotor 19 formed by a roll or the like on a guide rail from which the rotor 19 lifts the base 17 pivots out. 
     At least in the vicinity of each transfer station 9, 10, which is followed by another transfer station in the delivery direction, a moving bridge 20 or 21 can be moved and by means of which the conveyor 13 can convey away the gripped layer units so that either the associated transfer station 9 is overtravelled and the layer units are aligned with the associated transfer station 10. 
     The conveyor means 1 has a frame 22 with two lateral side plates 23 on whose facing insides are guided the running carriage of the conveyor 13 and the rotor 19, together with the moving bridges 20, 21. Each transfer station 9 or 10 has associated with it at least one transverse conveyor 24 or 25, which traverses one or both side plates 23 and is substantially located below the common, roughly horizontal running plane of the moving bridges 20, 21. The transverse conveyors 24, 25 are mounted with separate lifting devices 26, 27 independently of one another and in raisable and lowerable manner on lifting guides 28, 29, which are laterally located on remote sides of the transverse conveyors 24, 25. With each lifting device 26, 27 is associated a separately controllable lifting drive 30 or 31, which can be formed by a mechanical or pressure-operated drive and appropriately is provided not between the facing sides of the lifting devices, but instead below the same and/or on their remote sides. 
     Each transfer station 9, 10 or their transverse conveyors 24, 25 forms a support 32, 33 for the layer units to be transferred. Each support is formed by the upper side of a separate conveyor belt 34, 35 (See FIG. 3), which runs over a belt guide 36 or 37, which is raisable and lowerable with the associated lifting device 26 or 27. With each conveyor belt is associated a separate belt drive 38 or 39, which appropriately drives from the side remote from the adjacent belt guide 36, 37 and is located on said side. Thus, the two belt guides 36, 37 can project freely at right angles to the associated conveying direction from the guide and drive side, so that the conveyor belts 34, 35 can be easily drawn off and replaced from the area between the transverse conveyors 24, 25. 
     The delivery means 8 defines a conveying direction 40 and the discharging means 11, 12 formed by the transverse conveyors 24, 25 defines a discharge direction at right angles thereto and which is also roughly horizontal. Both the transverse conveyors 24, 25 can convey roughly parallel to one another, but optionally, in different planes. The conveying away takes place from the transfer stations through window-like passages 42, 43 in the side plates 23, which can be provided in one or both plates. Each transfer station 9, 10 can consequently convey away in at least two directions. 
     The moving bridge 20 of the transfer station 9 closer to the discharge station 7 is formed by two facing bridge parts 44, 45, which can be so moved against one another in an overtravelling position indicated in dot--dash line in FIG. 2, that they either mesh together or strike against one another, or are located projecting freely by roughly the same amount at a relatively small distance from one another. Each transfer station 9 or 10 is bounded by roughly vertical boundaries 46, 47 or 48, 49 in shaftlike manner at its sides transverse to the direction 40 and the internal spacing corresponds to the size of the layer units. At least one, and in particular, the second boundary 47 or 49 in the direction 40 is adjustable with a setting device 50 or 51 to different sizes roughly in the direction 40 and both boundaries 47, 49 can be separately adjustable by means of a common control drive. The transverse conveyors, boundaries and/or moving bridges can also be provided on a carrier, which is adjustable roughly in direction 40 with respect to the frame 22 or the passages 42, 43, as well as the conveyor 13. 
     By means of a separate setting device 52, 53, each bridge part 44, 45 can be adjusted and fixed by means of a control mechanism reciprocating roughly in direction 40. The bridge part 44 has a fixed part extending roughly to the output or discharge station 7 and a part adjustable with the setting device 52, which in the starting position terminates roughly flush with the boundary 46 and is located immediately on the top thereof. From said starting position, this portion of the bridge part 44 can be slid in direction 40 in contact-free manner over part of the width of the support 32. For this purpose, the displaceable portion is located on an underlying carriage 54 formed by a cross-beam on the outside of boundary 46 and which is guided in guides 55 on the insides of the cross plates 23 and is displaceably controlled by drives 56, e.g. working cylinders located in the vicinity thereof. A corresponding carriage 57 or cross-beam located below the integrally displaceable bridge part 45 is displaceably mounted in guides 58 located roughly at the same height and with drives 59 independently of the bridge part 45 in and counter to the direction 49, while also being fixed to the associated bridge part 45. This carriage 57 is located in the gap between the boundaries 47, 48 and on the underside of the bridge part 45. The guide for the setting device 50 can be located immediately below it. 
     Each bridge part 44 or 45, which simultaneously forms a running path between the discharge station 7 and the transfer station 9 or between the two successive transfer stations 9, 10 aligned in direction 40, has slot-like running gaps 63, 64, extending in the direction of arrow 40, for the lower gripping arms of the grippers 16. The conveyor 13 has a number of grippers 16 at least corresponding to the number of juxtaposed layer units and can be simultaneously controlled by means of a common drive. The gripping surface of each lower gripping arm is roughly located in the conveying plane defined by the top of the running paths, so that the gripping arm at least partly engages in the associated running gap 63 or 64. For this purpose, the bridge part 44, 45 is formed by plate-like guide fingers 60, 61 juxtaposed with the gap spacing and which are transversely adjustable and fixable with respect to the associated carriages 54, 57 for spacing adjustment purposes. In the case of the bridge part 44, in each case, one guide finger 60 is telescopically displaceably mounted in the underside of a fixed cover plate 62, which is in turn supported in transversely adjustable and fixable manner on a cross-brace adjacent to the boundary 46 and linking the side plates 23. The guide fingers 60, which are narrower than the cover plate 62, can be widened towards their free ends. For each transfer point of each transfer station a separate bridge part or guide finger and/or separate cover plate is consequently provided. 
     For each transfer station 9, 10 and in particular the last transfer station 10, in direction 40 is provided at least one plate-like support arm 65, which can be so moved in direction 40 over the associated support 33, that is spacedly engages over the same at least over part of its width. The end of the layer unit facing the gripper 16 can be supported on the support arm 65 until it is aligned by the conveyor 13 relative to the support 33. After this, the support arm 65 is again retracted over the boundary 48, so that the layer unit can drop down to the support 33 or on to a layer unit already positioned thereon. The support arm 65 is formed by the end of the bridge part 45 remote from the transfer station 9 or is rigidly connected thereto in operation, so that, like the guide finger 61, it is formed by support fingers between which are located running gaps 64. Thus, in one displacement position, the bridge part 45 is in the vicinity of the transfer station 9 for forming the moving bridge 20, while in the other position, it is in the vicinity of the transfer station 10 for forming the support arm 65. The guide finger 60 can form the corresponding support arm in the vicinity of the transfer station 9. 
     Using the conveyor means, working appropriately takes place according to the following method. The layer units, which can optionally be collected from smaller layers at the discharge station 7 are spaced in a transverse row and are simultaneously engaged by the conveyor 13 at their front transverse edges and are linearly drawn in direction 40, while the moving bridge 20 is located in the closed position indicated in dot-dash like manner in FIG. 2. Thus, the layer units can be moved as one through the delivery region of the transfer station 9 without delay or stopping. In order that the rear marginal region of the drawn layer unit slides adequately over the gap between the bridge parts 44, 45, the top of the bridge part 45 drops away in ramp-like manner at the associated end. 
     As soon as the rear transverse edge of the layer units has reached a distance from the free end of the support arm 65 which roughly corresponds to its displacement distance to the support position, the bridge part 45 is also moved in the direction 40 via the setting device 53. Consequently there is no further relative movement between the layer units and the support arm 65 until the layer units are located in oriented and completely contact-free manner over the support 33 raised to directly below the support arm 65. The latter is then retracted in opposition to direction 40 until flush with the boundary 48, so that the associated trailing marginal area of the layer unit drops down on to the support 33, while the leading marginal area is kept slightly higher by the fixed gripper 16. Immediately thereafter, the gripper 16 opens, moves in direction 40 roughly by the length of its gripping arms and consequently also frees the leading marginal area of the layer units to permit sinking onto the support 33. The support 33 is lowered until the top of the deposited layer unit is lower than the lowest running plane of the conveyor 13, so that the latter runs back over the layer unit counter to direction 40 and in the described manner can collect a further transverse row of layer units at the discharge station 7. Due to the withdrawal movement of the support arm 65, the bridge part 45 has been moved back into its bridge position. 
     It is assumed that at each transfer point of the transfer station 10 several, e.g. five, layer units have been stacked on one another and are to be conveyed away as a large stack. In the described manner, four further delivery cycles are performed, and now, on each occasion, the support arm 65 overtravels the top, already deposited partial layer. As a result of the withdrawal movement of the support arm 65, on each occasion, the bridge part 45 is brought back into it overtravel position for the transfer station 9. If now the relatively high large stack of superimposed layer stacks of a transverse row are to be conveyed away after or simultaneously with the lowering for the return of the conveyor 13, by starting up the belt drive 39 in one of the two directions 41, they are conveyed transversely out of the frame 22 and through the associated passage 43. During the time necessary for this conveying away and up to the emptying of the transfer station 10, the conveyor 13 can in the described manner collect at least one further transverse row of layer units and deposit same in the transfer station 9. 
     The bridge parts 44, 45 are retracted until roughly flush with the boundaries 46, 47 and the support 32 is moved directly below the running plane or underside of the bridge part 44 or the guide finger 60. During the transfer, the latter can function as a support finger in roughly the same way as described relative to the support arm 65 and the working of the gripper 16 can also take place correspondingly. 
     Following the corresponding lowering of the support 32, the gripper 16, whose base 17 or carriage does not have to perform any vertical movements, returns to the discharge station 7 and collects the next, furthest forward transverse row of layer units. In the meantime, the moving bridge 20 is closed and in the transfer station 10, a large stack can be formed in the described manner, while now the conveying away from the transfer station 9 takes place in one of the directions 41, so that the latter is again free when a transfer cycle for the transfer station 10 is ended. 
     According to FIG. 3, each discharge means 11 or 12 is moved out from both sides of the frame 22 and can be driven in both opposite directions 41. Thus, each discharge means 11 or 12 can convey on two separate, further processing machines or the like, e.g. packing means, which can be located on both sides of the frame 22 or the T-like conveying conveyor means 1. Also in the case of a conveyor means with only a single transfer station, it can be appropriate to divide at least one transverse conveyor 24 or 25 between two adjacent transfer points, e.g. roughly in the center of the length of a row of layer units, so that then one partial conveyor discharges in one direction and other in the opposite direction 41, and for the same conveying speed, a correspondingly shorter time is required until the transfer station is completely emptied. The layer units of the particular transverse row need not in the case of the inventive construction be drawn apart to a reciprocal spacing for conveying away purposes and instead can remain directly engaged from the discharge station 7 to the conveying away means. After or during conveying away, they can be kept spaced, e.g. by corresponding acceleration. 
     Whereas in the embodiment according to FIG. 3, each transverse conveyor 24, 25 allows conveying away to both sides, the conveyor means 1a according to FIG. 4 has all conveying away in one direction, so that the transverse conveyors 24a, 25a need only be led out to one side. Closely juxtaposed, successive transverse conveyors can be led out in spaced manner outside the conveyor means 1a and for this purpose e.g. one transverse conveyor 25a is connected to a running arc 66 for the layer units. 
     The conveyor means 1b according to FIG. 5 has a transverse conveyor 24b only led out in one direction and a transverse conveyor 25b led out in the opposite direction. In the conveyor means 1c according to FIG. 6 the transverse conveyor 24c is only led out to one side and the transverse conveyor 25c to both sides. Conversely the transverse conveyor 24c could be led out to both sides and the transverse conveyor 25c to only one side. It is also possible to randomly combine the embodiments according to FIGS. 3 to 6, optionally in the case of more than two successive transfer stations.