Patent Publication Number: US-2007095874-A1

Title: Apparatus and method for the transport of web-like material

Description:
This application claims the priority of German Patent Document No. 10 2005 042 439.2, filed Sep. 7, 2005, the disclosure of which is expressly incorporated by reference herein.  
     BACKGROUND AND SUMMARY OF THE INVENTION  
      The invention relates to an apparatus and method for the transport of web-like material, in particular printed webs or packets of printed webs fed from a fold former positioned downstream of a printing machine with a roll that can be driven and against which pressure-application rolls can be adjustably pressed.  
      The pressure-application rolls together with the driven draw-rolls, form an in-draw gap. It is necessary, therefore, to take measures to effectively prevent the risk of fingers being crushed. In the known arrangements a protective hood is provided for the pressure application rollers. This certainly offers adequate protection against the risk of fingers being crushed. It is a disadvantage, however, that the protective hood prevents a clear view being obtained of the in-draw gap and of the transported web material. A quite special disadvantage is that the space between a protective hood and a pressure-application roll can become smaller which leads to the pressure-application roller being blocked. Experience has shown that when webs of paper are being processed so-called spaghetti-formation often develops as a consequence of the faulty adjustment of slitting knives, etc., in that the spaghetti collects between one or more protective hoods and the associated pressure-application rolls and block them after a period of time. This results in the affected pressure-application rolls grinding on the driven draw-rolls which leads to the flattening and, consequently, to the destruction of the pressure-application rolls.  
      Taking this as a starting point, it is therefore the object of the present invention to improve an arrangement of the type described above with simple and economic means such that the use of a protective hood can be dispensed with while nevertheless providing adequate protection against the risk of fingers being crushed.  
      This objective is achieved according to the invention in that the pressure-application rolls are carried by a relevant assigned position-setting assembly which exhibits at least one actuating element capable of receiving an impulse from a pressure-applying agent, where the impulse from the pressure-applying agent can be controlled according to a pre-settable timing sequence by a control device.  
      These measures offer the possibility in an advantageous manner that the position-setting procedure does not have to operate suddenly as before but rather that it can proceed comparatively slowly and/or in several stages. This ensures that that an operator, who when adjusting the setting of the pressure-application rolls—an activity which in many cases requires direct vision of the relevant pressure-application roll—must insert his/her fingers into the danger area to detect the adjustment movement of the pressure-application roll, has sufficient time to withdraw his/her fingers before the position-setting procedure is completed or the full application of pressure takes effect. It is possible, therefore, advantageously to dispense with all other protective measures. Also advantageously, there is consequently no longer any danger that a pressure-application roll can be blocked in the event of spaghetti build-up and destroyed as a result. In addition to providing a high level of working safety, the measures according to the invention accordingly guarantee a high level of process security and freedom from the risk of breakdown which has a beneficial effect upon the overall economic situation.  
      Thus, the control device can expediently exhibit a control valve which is designed as a proportioning valve and arranged in a supply line which provides a pressure-applying agent and is assigned to the position-setting assembly. With the assistance of a proportioning valve it is possible to achieve in an advantageous manner not only any desired timing sequence but also any desired final level of applied pressure—and to do so in a simple way.  
      A further extension of the present invention is that the control valve can be controlled by a memory-endowed computer in which the desired timing sequence together with, preferably the desired level of applied pressure is stored. This ensures an automatic implementation of the position-setting procedure. A further advantage is that in the event of a change in the desired timing sequence, etc., only the relevant software needs to be amended. It is therefore possible to adapt to the circumstances of the individual situation in a simple manner.  
      In a further extension of the present invention, the position-setting assembly can exhibit a housing block with two projectable pistons where each one seals off a working space which can receive an impulse from a pressure-applying agent and where the ends protruding out of the housing block are connected by a yoke upon which is securely mounted at least one appropriate axle carrying at least one pressure-application roll. The twin pistons provided here with the yoke carrying the axle provide a high degree of stability and consequently very smooth running of the pressure-application roller. In addition, the integration of the cylinder-piston frame in a housing block results in a very compact arrangement.  
      A further expedient advantage can be that at least one return positioning spring in the housing block is assigned to the yoke. Consequently, the piston can be designed as simple operating pistons which permits a simple form of construction.  
      Further advantageous developments and expedient extensions of the overriding measures of the present invention are provided in greater detail in the example description below and by reference to the drawings.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      In the accompanying drawings:  
       FIG. 1  shows a partial view of the upper part of a folding section with a fold former and an associated in-draw arrangement;  
       FIG. 2  shows a pressure-application roll with an associated position-setting assembly in the fully engaged position;  
       FIG. 3  shows the arrangement according to  FIG. 2  in the disengaged position;  
       FIG. 4  shows an applied pressure/time diagram; and  
       FIG. 5  shows a view of a pressure-application roller arranged so as to be laterally displaceable. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
       FIG. 1  illustrates a fold former  2  arranged in the upper part  1  of a folding section to which a web packet consisting of several webs imposed upon one another is directed and which come from an upstream printing machines not shown in any greater detail here. For this purpose, the individual webs leaving the printing machine run over a so-called harp consisting of several in-feed rolls  3 , the deflection rolls  4  and the in-draw devices  5  arranged successively. Each of the in-draw devices  5  consists of a draw-roll  7  extending the full width of the machine and powered by an assigned drive motor  6  where adjustable pressure-application rolls (trolleys)  8  can be pushed against the draw-roll. The pressure-application rolls  8  are mounted on freely rotating bearings and rotate solely under the influence of friction.  
      The pressure-application rolls  8  can be positioned against or away from the relevant assigned draw-roll  7 . All the pressure-application rolls  8  or selected pressure-application rolls may be involved. To serve this purpose, the pressure-application rolls  8  are mounted in a position-setting assembly  9  which permits the pressure-application roll  8  to move at right angles to its axis. As can be seen from  FIGS. 2 and 3  each position-setting assembly  9  contains a housing block  10  with an integrated cylinder-piston arrangement to effect the desired adjustment of the assigned pressure-application roll  8 . To that end, the housing block  10  is provided with two bored holes which run in the engaged and disengaged position-setting direction. These holes are closed at the rear by a fitting  11  and each of them is penetrated internally by a length of shaft functioning as a piston  12  which together with the fitting  11  demarcates a working space  14  which can be dynamically filled through a supply line  13  by a pressure medium, preferably compressed air. The ends of the pistons  12  remote from the working space  14  protrude out of the housing block  10  and they are connected to one another by a yoke  15  forming a portal-like configuration which guarantees high stability. A protruding axle  16  is secured to the yoke  15  on which the relevant assigned pressure-application roll  8  is mounted in a manner permitting free rotation. The axle  16  is flatted where it sits on the yoke  15  to provide plane contact surfaces.  
      The pistons  12  are designed as simple working pistons which when pressure is applied to the relevant assigned working space  14  are pushed away from the basic driven-in position illustrated in  FIG. 3  to the basic driven-out position illustrated in  FIG. 2 . The reverse motion is effected by a return positioning spring  17 . To facilitate this the housing block  10  is provided with a central bored hole  18  into which a pin  19  attached to the yoke  15  penetrates. The yoke side of the bored hole  18  is closed by a fitting  20  which is pierced by the pin  19 . The side of the pin  19  that is remote from the yoke is provided with a spring plate  21 . The return spring  17  is supported on one side by the fitting  20  and on the other side by the spring plate  21 . In the course of the position-setting procedure, i.e., when driving out the pistons  12 , the return positioning spring  17  is compressed. As soon as the pressure in the working spaces  14  drops, the return positioning spring  17  pushes back the yoke  15  and the pressure-application roll  8  carried upon it from the basic engaged position shown in  FIG. 2  to the basic disengaged position shown in  FIG. 3  in which the pistons  12  are driven up to the stop on the rear-mounted fittings  11  in the housing block  10 .  
      In order to prevent any risk of fingers being crushed, the position-setting movement of the pressure-application rolls  8  does not take place suddenly, but rather, slowly and or in several stages with increasing speed. To that end, as depicted in  FIG. 2 , a control valve  22  is arranged in the common supply line  13  from a source of pressure which is not illustrated in any more detail to the two working spaces  14  in the housing block  10 . Expediently, this valve is designed as a proportioning valve and by its use the generation of pressure in the working spaces  14  can be controlled such that a desired timing sequence is obtained for the generation of pressure in the working spaces and, consequently, of the setting and application of pressure upon the pressure-application rolls  8 . A control device  23  is provided to activate the control valve  22 , which control device expediently contains a computer into the memory of which the desired timing sequence can be stored.  
      As mentioned above, the generation of pressure in the working spaces  14  and, correspondingly, the execution of the position-setting procedure can proceed slowly or in several stages. A multistage position-setting and pressure-application procedure is illustrated in  FIG. 4 . The function  24  depicted schematically in  FIG. 4  schematically shows the course of the level of applied pressure with time.  
      In a first stage here, the pressure-application roll  8  is placed against the assigned draw-roll  7  with no or negligible force. In a second stage there is a progressive increase in the level of applied pressure up to a desired norm value which develops in a linear or slow manner. It is expedient if in the first stage the level of applied pressure is only slightly higher than the return force exerted by the return positioning spring  17 . The selected norm value for the second stage, i.e., the final application pressure, can also be stored in the memory of the computer. In the case of different product situations, e.g., wide format or tabloid format, different norm values can be stored so that the norm value can also vary.  
      The first stage can be started by a switching procedure where the pressure rises comparatively quickly to the abovementioned strength of the return positioning spring  17 , which is indicated by the stage “s”. Continued switching from the first to the second stage can result from a time-function element in the control device  23  which is initiated at the beginning of the first stage and continues the switching procedure at the end of the second stage. It is also conceivable to arrange for the further switching procedure from the first to the second stage to be dependent upon the operating circumstances of the printing machine, for example, the instant of the first instruction to run, i.e., the commencement of printing. To achieve this, the control device  23  can be connected to the control system of the printing machine as is indicated by an input  25 . To facilitate a manual start the control device is provided with an input  27  connected to a switch  26 . The first stage can also be started by this means. It is also conceivable to start the first stage automatically in dependence upon the operating circumstances of the printing machine, for example at the completion of the feed-through operation.  
      Once the second stage has commenced, the pressure rises comparatively slowly along the ramp “r” to the abovementioned norm value. In the illustrated example the ramp r is linear. A non-linear or stepped rise is, however, also conceivable.  
      The pressure-application rolls  8  are positioned only in the pressure-free areas of the relevant web in motion. Correspondingly, the pressure-application rolls  8  can be arranged to be adjustable over the width of the machine. To that end and as can be seen from  FIGS. 1 and 5 , each position-setting assembly  9  which carries a pressure-application roll  8  is provided with a carriage  28  which accepts the appropriate housing block  10  and which is displaceably mounted on a traverse  29  extending across the width of the machine. The position of the carriages  28  can be changed either manually or by powered means, for example by a motor-driven threaded shaft, and then locked in the desired position. This is effected by a clamping device which is shown in  FIG. 5  only by its activation lever  30 .  
      In the illustrated example the clamping device for locking the relevant assigned carriage  28  is operated manually by the activation lever  30 . In the case of motorized adjustment of the position of the carriage  28  it is also possible to provide mechanically operated locking by, for example, an electromagnetic device.  
     LIST OF REFERENCE SYMBOLS  
     
         
         
           
              1 Upper part of a folding section  
              2 Fold former  
              3 In-feed rolls  
              4 Deflection rolls  
              5 In-draw devices  
              6 Drive motor  
              7 Draw-roll  
              8 Pressure-application rolls  
              9 Position-setting assembly  
              10 Housing block  
              11 Fitting  
              12 Piston  
              13 Supply line  
              14 Working space  
              15 Yoke  
              16 Axle  
              17 Return positioning spring  
              18 Bored hole  
              19 Pin  
              20 Fitting  
              21 Spring plate  
              22 Control value  
              23 Control device  
              24 Ramp function  
              25 Input  
              26 Switch  
              27 Input  
              28 Carriage  
              29 Traverse  
              30 Activation lever  
           
         
       
    
      The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.