The invention relates to a device for conveying and depositing sheets on at least one stack, with a device for moving the conveyor roller laterally in the conveying direction of the sheets and equipment for the transfer of rotation to the conveyor roller, in particular for operating within a depositing device of a machine for processing sheets, in particular a digital multicolor printing press.
In paper processing machines, in particular in multicolored printing presses, subassemblies are used at the end of the paper path as an extension arm that controls the depositing paper sheets on an already existing stack or which can build a new stack. To this end, there are systems, for example, that work with negative pressure and overpressure, or which operate, in a purely mechanical way, e.g., by tappets and holding down systems with rollers located above. Such mechanical systems, as describe in the publication of disclosure of patent DE 199 57 574 A1, make it possible to deposit sheets with a very high degree of precision. Fewer material-intensive members are used than with customary extension arms, whereby sufficient space is available in the area around the stack to remove the stack, to inspect it or to further process the sheets.
In the extension arm described in the patent DE 199 57 574 A1, a last pair of rollers in the paper path in particular is used as a conveyor roller pair, which is attached above a pair of tappets and a hold down device. The function of this conveyor roller pair is used in conjunction with the pair of tappets and the holding down device to deposit sheets conveyed in the area of the extension arm that fit perfectly on a paper stack or to build a new stack.
The transport roller pair can be moved by rotation and can be laterally moved in the conveying direction of the sheet. The surface of the conveyor roller has a very high friction value, while the tappets located directly below the conveyor rollers on their side facing the rollers have a very low friction value. The lateral mobility of the conveyor rollers makes it possible to correct any misalignment of a sheet, at least in its position transverse to the conveying direction. Furthermore, the lateral position of sheets on a stack can be controlled, so that, for example, offsets for differentiating between the various printing jobs within the stack can be produced.
The sheets are quickly conveyed to the stack by rotating rollers. The transfer of the rotation to the conveying rollers takes place by a drive shaft. The rollers are attached to an aluminum pipe that is connected to the drive shaft. The drive shaft can then be driven by a toothed belt.
For the lateral movement of the conveyor roller in DE 199 57 574 A1, an actuator is provided above the conveyor rollers, which drives a spindle. In order to prevent twisting, a swivel head is fastened to a spindle, which drives a rod. The rod is screwed into a non-rotating adjusting ring on the aluminum pipe of the conveyor rollers. The adjusting ring is transversely coupled to the conveyor rollers, which makes it possible to move the conveyor rollers laterally.
The rod drives the swivel head on the spindle by an opening. When a new piece of paper is to be deposited on the stack, it is necessary that the conveyor rollers be removed from the surface of the stack, for which lever arms are provided on the drive shaft.
The speed with which the conveyor rollers can be laterally moved is limited here. It can be increased, for example, via a spindle that has a larger spindle stroke. However, such an extension of the system would entail substantial cost increases.
The spindle, which effects the lateral movement of the conveyor rollers, is shown here open and unprotected. As a result, it is easily soiled, and it is also susceptible to mechanical effects. Consequently, it may be damaged or at least its function may be impaired.
The drive shaft for transferring the rotation to the conveyor rollers may be driven by means of a toothed belt. Since there may be a difference in height between the sides of the sheet stack, a tilt of the drive shaft may also be required via the conveyor rollers. This tilt may amount to 4°. Since the wheels of the tooth belt are rigidly connected with the drive shaft, this tilt is also transmitted to the flanged rim pulleys of the toothed belt wheels. As a result, the toothed belts are pushed to the edge of the flanged rim pulleys and are constantly rubbed by the tilting position. Due to the wear and tear of the toothed belt, they have to be changed often.
The basic task of the invention is to cost effectively raise the speed with which the conveyor rollers are laterally moved in the conveying direction of the sheets. In addition, a protection of the spindle against soiling and external, undesired mechanical effects and/or damages is also achieved. Furthermore, the intervals in which the toothed belt wheels have to be changed due to wear and tear is extended.
The task is solved according to the invention, whereby members of the device for the lateral movement of the conveyor rollers and members of the device for the transfer of rotation are located in a pipe to which the conveyor rollers are attached.
The conveyor rollers are securely attached to a rod, according to the invention. This rod is connected with two lever arms in such a way that the rod can rotate freely and can be moved laterally. The rod with the conveyor rollers can be vertically lifted by the lever arms, which is necessary when adding new sheets to the stack. The advantage of this arrangement is that the rod within the holder can rotate, since the latter is not hindered by the lever arms. As a result, lateral movements of the rod and thus of the conveyor rollers are possible that are not impaired by the holder. Since the conveyor rollers in this embodiment of the invention are directly connected with the rod, they can also be lifted vertically, without another member having to be connected between them.
According to the invention, the device is such that members for the transfer of the rotation to the conveyor rollers are located within the rod. They contain a drive shaft, which is arranged on the side of the rod and which is form-fitted with the rod. The drive shaft can be driven with the coupled rod and it can be moved rotationally, so that, in addition, a torque can be transmitted to the conveyor rollers. In this manner, the driving mechanism of the conveyor rollers is located compactly within the rod. In addition, it is not necessary for the drive shaft to have the entire width of the extension arm. The production of the extension arm thus requires less material. Furthermore, the other end of the rod remains free, so that members for other devices can be fitted here. It is also possible that each conveyor roller be individually driven by separate drive shafts. As a result, it can be guaranteed that the conveyor rollers can rotate at different speeds. Different rotational speeds of the rollers can be used advantageously to correct the position of the sheets. If the drive shaft does not pass through between the two conveyor rollers, the rotating axes of the rollers can also adopt different angles to each other, but they must not run parallel to each other. Other correcting possibilities for the sheet position are thus provided. The sheets can also be accessed more easily from the top, since a limiting member is omitted. Furthermore, sources of error are omitted, since fewer wear and tear parts are involved in the transmission of rotation. Since the drive shaft now lies completely within the rod, it is no longer exposed to soiling and potential sources of malfunction.
Advantageously, it is further provided according to the invention, that the drive shaft not be directly connected with the rod. A carrier is provided for this purpose, whose connection is perfectly fitted with the drive shaft and the rod. The carrier can be freely moved on the drive shaft and/or the inside of the rod. For this purpose, both the drive shaft as well as the inside of the rod have a suitably adjusted shape.
The carrier can be adjusted or press-fitted into the rod or into the drive in such a way that, with regard to an interconnecting point between the drive shaft and rod, it can no longer be moved horizontally; as a result, friction points can advantageously be avoided and the stability of the system consisting of a drive shaft, carrier and rod, increases. First, the horizontally freedom of movement of the carrier on at least one of the surfaces, inside the rod or the top surface of the drive shaft, is guaranteed, so that the rod can be laterally moved. Only in this fashion can the rollers also be laterally adjusted for positioning of the sheets. The drive shaft transmits the rotation to the conveyor rollers via the carrier; the most favorable condition for this is when one side of the carrier is anchored. According to the invention, it is thus envisaged to anchor the carrier to the inside of the rod. The carrier is connected with the drive shaft for rotation and disconnected for later movements.
In accordance with the device, the task of the invention is further solved in such a way that the members of the device for lateral movement of the conveyor rollers are located inside the rod. It is thus provided that in the other end of the rod opposite the device for the transmission of rotation, there is a spindle with a ball screw nut attached to it. The ball screw nut is connected with the rod in such a way that it is completely disconnected for rotation. To this end, in accordance with the device, a connection between the ball screw nut and rod in the form of bearings is provided. Furthermore, the ball screw nut is coupled to the rod for lateral movements. According to the invention, these couplings can take place via the bearings, which provide a rotational disconnection of the ball screw nut from the rod. It is provided that the ball screw nut can be connected perfectly form-fitted with the bearings, so that lateral movements of the ball screw nut can be directly transmitted to the bearings and thus to the rod as well. In this manner, a considerably precise control of the conveyor rollers can thus take place, since with the perfectly fitted attachment of the ball screw nut provided here, it can thus be attached between two bearings, so that practically no more play exists. In this embodiment of the invention, the spindle lies inside the rod and it is thus protected from soiling and mechanical loads. As a result, fewer damages and malfunctions of the spindle occur. Since the spindle here effects the lateral movement of the rod, a higher speed of the lateral movement can easily be reached via an increased r.p.m. Here, no additional members are involved in the transmission of movement, which would malfunction under an increased speed, and even the drive itself is not a limiting member here.
Advantageously, it is provided in the invention that the lever arms are connected with the rod via swivel heads. Preferably, the swivel heads should be located in the area around the end of the rod. In this way, it is possible to disconnect the lever arms by tipping the rod. Tipping thus always occurs when the stack has a difference in height between various points of its surface. The conveyor rollers lie temporarily on the stack during the sheet depositing process. In this way, its tilting is directly transmitted to the rod. Since the lever arms are disconnected via the swivel heads from the rod during the tilting, favorably fewer shear forces are exerted on the lever arms.
According to the invention, it is provided that both the drive shaft, as well as the spindle, is connected with drive members via cardan (universal) joints. These cardan joints should advantageously be concentric to the swivel heads on the axis of the rod. In this way, it is ensured that the tilting of the conveyor rollers is not transmitted to the lever arms or to the drive members, the drive shaft and the spindle. The driver members should be connected with the lever arms via bearings; there should be no direct connection with the rod. The drive members should be either rotational via the drive shafts and bearings, or disconnected from the rod for lateral movements. According to the invention, toothed belts can be provided, which transmit the force to the drive members in the form of toothed belt wheels. The tooth belt wheels are provided with flanged rim pulleys, which the toothed belts surround laterally. By tipping the toothed belt wheels relative to the toothed belts, the toothed belts run down the flanged rim pulleys and are thus worn out.
This tipping can thus be avoided by the cardan joints and, as a result, the service life of the toothed belts can be extended. The same also applies for other driving systems, such as geared wheels.
In a further expansion of the invented device, at least one position-locating unit, to identify the position of the rod, in particular the position of the conveyor rollers, at least one side of the rod is provided. It can be provided in the area surrounding a swivel head, preferably on a lever arm. The position-locating unit can preferably include a fork light barrier on the lever arm and a disk, which is located on the rod. This position-locating unit can fulfill two functions. It can prevent the rod from being moved so far that a swivel head, a drive member or other members of the device within the toothed belt wheel are damaged or destroyed. The disk is anchored in a fixed position on the rod. This position is chosen so that the disk then immediately releases the fork light barrier if the lateral movement of the rod exceeds a maximum. In accordance with the device, two position-locating units are provided at each end of the rod.
In a second embodiment, the position-locating unit can be used to calibrate the position of the conveyor rollers. In this case, only a position-locating unit is required. Since the distance of the disk to the rod of the conveyor rollers is constant and known, by detecting the position of the disk, the position of the conveyor rollers can be directly concluded. This is advantageous in order to ensure the highest depositing of the sheets on the stack.
Embodiments, which are able to provide further characteristics of the invention, but to which the invention is not limited in scope, are illustrated in the drawings in which:
With the configuration, as shown in
In order to ensure an exact lateral movement of a sheet and to pile up a stack in a desired position perpendicular to the sheet conveying device, the absolute position of conveyor rollers 1 must be determined. To this end, a position-locating unit, consisting of a fork light barrier 19 and a disk 20, which is anchored to rod 2, is located at the end of rod 2. Before the sheet can be conveyed, the absolute position of the conveyor rollers is determined via this position-locating unit and device 27 for lateral movements of the conveyor rollers 1 is calibrated with this unit. For this purpose, rod 2 is laterally moved so far, that the outer rim of disk 20 is driven through the fork light barrier 19. As a result, a signal is given, so that the position of disk 20 is now known. Since the distance between conveyor rollers 1 and disk 20 cannot be changed, the result is that now the position of conveyor rollers 1 can be precisely determined. This knowledge can be used by control electronics, which is not shown here, to deposit the sheet as targeted and precisely lateral to its conveying direction.
A second position-locating unit, consisting of a fork light barrier 19 and a disk 2, is also located on rod 2. This unit, in cooperation with the first position-locating unit, is used to prevent rod 2 from being moved too far, which would lead to a destruction of members within a toothed belt wheel 6 or 7 or which would lead to the lateral movement of conveyor rollers 1 or to the transmission of rotation to the conveyor rollers 1 by members of one of the devices 27 or 28. Since rod 2 is inserted up to the toothed belt wheels 6 and 7, a lateral movement of rod 2 beyond a maximum must be avoided. Disks 20 are thus located in positions in rod 2 that are measured in such a way that the respective outer rims of the disks release the fork light barrier 19, if the lateral movement of rod 2 just reaches this maximum.
The lateral movement and the transmission of rotation can be ensured with the members of the device shown in
The members of the device 27 for lateral movement of the conveyor rollers 1 shown in
The lateral movement of ball screw nut 14 takes place herein via spindle 13. Spindle 13 is rotated via cardan joint 12 and drive shaft 11. The transmission of the rotation takes place externally by the toothed belt wheel 6, which is driven by a toothed belt (not shown in greater detail), which should lie between the flanged rim pulleys. In this manner, a lateral movement of rod 2 can be achieved by an external actuation via a toothed belt.
For further anchoring of ball screw nut 14 and sleeve 16, a clamping block 18 is attached to the end of sleeve 16. This clamping block 18 has a wrench opening across flats, as illustrated in FIG. 4. It is more precisely configured as a dihedron. This clamping block 18 is fitted into sleeve 10, so that no lateral movement of sleeve 16 is possible. Sleeve 10 is used herein to connect the toothed belt wheel 6 to lever arm 4 via a ball bearing 9. In order that rod 2 can be moved laterally at least up to a maximum, an empty space 29 inside the toothed belt wheel 6 is provided. In order that rod 2 can also be vertically tipped, without this tipping being transmitted to the toothed belt wheel 6, rod 2 is connected with lever arm 4 with a swivel head 3. There is no direct connection between clamping block 18 and the toothed belt wheel 6. In order to prevent movements between clamping block 18 and sleeve 10, when rod 2 is vertically tipped, a space 30 is envisaged above sleeve 16 and clamping block 18. This makes it possible for rod 2 to be tipped up to a maximum angle provided by an empty space 30, without clamping block 18 or sleeve 16 inside sleeve 11) being aware of it.
It can be seen that the functionality of device 28 for the transmission of rotation to conveyor rollers 1 in
Drive shaft 25 has a wrench opening across flats, which is synchronized on a carrier 26. This carrier 26 thus can not be twisted with regard to drive shaft 25, but it can be freely moved laterally on drive shaft 25. On the other hand, the carrier 26 is also connected with rod 2, which has a corresponding fit, in such a way that it cannot be twisted. The carrier 26 cannot be freely moved with regard to rod 2, and thus transfers a rotating movement of drive shaft 25 directly to rod 2. On the other hand rod 2 can also be moved freely laterally, without this movement being transferred to drive shaft 25, since carrier 26 can slide freely in this direction on drive shaft 25. Also, in order to prevent the lateral movement of rod 2 from damaging any members inside the toothed belt wheel 7, an empty space 31 in the longitudinal direction within sleeve 22 is provided. Another empty space 32 is located above rod 2 within toothed belt wheel 7 between rod 2 and sleeve 22, so that rod 2 can also tip without doing any damage. In this way, conveyor rollers 1 can be laterally moved and adjusted to the difference in height of the stack, without damaging toothed belt wheel 7 and without heavy wear and tear on the toothed belt.
Another protection from the lateral movement of rod 2 and for calibration of the lateral movement of conveyor rollers 1 is provided by the position-locating unit, including fork light barrier 19 and disk 20. The exact functionality has already been explained with regard to FIG. 1.
It can be seen more precisely in
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
Number | Date | Country | Kind |
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101 60 382 | Dec 2001 | DE | national |
Number | Name | Date | Kind |
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4884909 | Watanabe et al. | Dec 1989 | A |
Number | Date | Country |
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199 57 574 | Sep 2000 | DE |
Number | Date | Country | |
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20030178766 A1 | Sep 2003 | US |