Method of setting the folding-nip width of a plurality of pairs of folding rollers, and folding machine in which the method can be implemented

Information

  • Patent Grant
  • 6743161
  • Patent Number
    6,743,161
  • Date Filed
    Tuesday, December 10, 2002
    21 years ago
  • Date Issued
    Tuesday, June 1, 2004
    20 years ago
Abstract
In the case of the method of setting the folding-nip width of a plurality of pairs of folding rollers which are provided on a folding machine, the two folding rollers (12 to 22) of the pairs of folding rollers are brought into contact with one another. A sheet is then guided through between the two folding rollers (12 to 22) of the pairs of folding rollers, as a result of which at least one of the two folding rollers (12 to 22) moves in relation to the other, with a folding nip being formed in the process, it being the case that, for each pair of folding rollers, a measured value corresponding to the folding-nip width is detected as the sheet is guided through. Finally, the folding-nip widths of the individual pairs of folding rollers are set by adjustment of the at least one moveable folding roller (14 to 22) by means of a drive (42), which is connected kinematically thereto, based on the corresponding measured values which have been detected.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The invention relates to a method of setting the folding-nip width of a plurality of pairs of folding rollers which are provided on a folding machine.




2. Description of the Related Art




DE 298 20 796 U1 discloses a folding machine which has a plurality of pairs of folding rollers which are arranged one behind the other in the sheet-passage direction and between which one sheet is guided through in each case. One folding roller of the first pair of folding rollers is arranged in a stationary manner, while the other folding roller is arranged in an adjustable manner in order to form a folding nip with the other folding roller of the corresponding pair of folding rollers. The adjustable folding rollers are prestressed in the direction of the stationary roller in each case by a prestressing device. Arranged on the feed table of the known folding machine is a thickness-measuring device, which measures the thickness of a first passing sheet which is fed to the first pair of folding rollers. The measured value determined is passed on to a process computer. There, with a respective folding layout being taken into account, the necessary folding-nip widths are calculated. Thereafter, the actuating drives are actuated, in order to adjust the adjustable folding rollers, until actual values of position indicators correspond to the desired values which have been calculated. Corrections may be carried out both via a keyboard and via manual spindle drives, which act in parallel with the motor drives and also act on the position indicators.




Determining the necessary folding-nip width by computer is problematic because, in addition to the sheet thickness and the tolerances thereof, the setting values also have to take account of air inclusions, the sheet compression, the roller wear and the roller contamination (applications of ink and powder).




In the case of a further apparatus, which is known from U.S. Pat. No. 4,125,254, first of all all the folding-nip widths are set to zero. Then, a sample sheet is guided through the folder, as a result of which the adjustable folding rollers are deflected and arrested in this deflected position. Corrections to the folding-nip width, however, are not possible in the case of this folding machine, with the result that the operation of setting the folding-roller nip is not practicable.




SUMMARY OF THE INVENTION




The object of the invention is to provide a method of setting the folding-nip width of a plurality of pairs of folding rollers by means of which the folding-nip width can be automatically set, and corrected, in a straightforward and precise manner.




This object is achieved according to the invention by a method of setting a folding-nip width of a plurality of pairs of folding rollers which are provided on a folding machine, each pair of folding rollers including at least one adjustable folding roller, comprising the following steps:




the two folding rollers of said pairs of folding rollers are brought into contact with one another,




a sheet is passed between said two folding rollers of said pairs of folding rollers, whereby said at least one adjustable folding roller moves in relation to the other, so that a folding nip is formed, a value corresponding to said folding-nip width being detected for each pair of folding rollers as said sheet is passed therebetween, and




said folding-nip widths of said pairs of folding rollers are set by adjustment of said at least one adjustable folding roller by means of a drive, which is connected kinematically thereto, based on the corresponding detected values which have been detected.




Since, in the case of the method according to the invention, the folding-nip width is measured on all the pairs of folding rollers as a sheet passes, and the folding-roller nip is then set by the associated drive at each pair of folding rollers in accordance with the measured values which have been detected, there is no need for any complicated calculation of the folding-nip widths in dependence on a thickness measurement, as is the case with the prior art known from DE-298 20 296. The method according to the invention operates without measuring the thickness of individual sheets and defective nip-width calculation. Moreover, it is possible to take account of air inclusions, the sheet compression, the roller wear and the roller contamination. Correction of the folding-nip widths is possible by the drives being activated correspondingly by a process control means, it being possible for the correction values to be entered from an operating terminal, e.g. a keyboard.




In the case of the method according to the invention, it is preferably possible for properties of a selected folding layout to be taken into account during the setting operation. Such folding layouts may be constituted, for example, by a zigzag fold or a parallel fold.




Furthermore, the measured values which have been detected may be compared with previously determined or measured reference values in order to determine roller wear or roller contamination.




The folding rollers are preferably brought into contact with one another by means of the drive, which is connected kinematically to an adjustable folding roller.




The method according to the invention can be used in a folding machine having




a plurality of pairs of folding rollers which are arranged one behind the other in a sheet-passage direction and comprise an adjustable folding roller and a stationary folding roller or two adjustable folding rollers,




each adjustable folding roller being associated a measuring device, which, as a sheet passes, detects a value corresponding to the width of the folding nip between said two folding rollers of a pair of folding rollers, and passes this value on to a process computer, and




connected kinematically to each adjustable folding roller is a drive which is controlled by said process computer on the basis of said values, detected during sheet passage, on the corresponding pair of folding rollers in order to set an optimum width of said folding nip.











BRIEF DESCRIPTION OF THE DRAWING




An exemplary embodiment of the folding machine according to the invention will be explained in more detail with reference to the attached drawing, which shows, schematically, a buckle folder of a folding machine according to the invention.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS




The buckle folder


10


has six folding rollers


12


to


22


which are arranged in parallel with one another and are arranged one after the other in the sheet-passage direction B. The folding rollers


12


to


22


form 5 pairs of folding rollers, the first pair of folding rollers being formed by a folding roller


12


, which is mounted in a stationary position such that it can rotate, and the adjustable folding roller


14


, the second pair of folding rollers being formed by the folding roller


14


and the adjustable folding roller


16


, the third pair of folding rollers being formed by the folding roller


16


and the adjustable folding roller


18


, the fourth pair of folding rollers being formed by the folding roller


18


and the adjustable folding roller


20


, and the last pair of folding rollers being formed by the folding roller


20


and the adjustable folding roller


22


.




In each case one buckle plate


24


to


30


is arranged downstream of the first to fourth pair of folding rollers.




The adjustability of the folding rollers


14


to


22


is explained in more detail hereinbelow with reference to the second folding roller


14


. The folding roller


14


is mounted such that it can rotate at the free end of one arm


34


of a two-armed link


33


, it being possible for the latter to be pivoted about a machine-mounted spindle


36


. Acting on the second arm


35


of the link


33


is a compression spring


38


, by means of which the folding roller


14


is prestressed in the direction of the folding roller


12


. The second arm


35


of the link


33


, furthermore, is connected kinematically to an actuating element


42


for the purpose of adjusting the folding-nip width between the folding rollers


12


,


14


. Moreover, the link


33


is assigned a displacement-measuring system


40


, which measures the deflection ΔS of the link


33


.




The actuating elements


42


and the displacement-measuring systems


40


are connected to a process computer


44


, which controls the actuating elements


42


based on the measured values which have been detected by the displacement-measuring systems


40


. Connected to the process computer


44


, furthermore, is an operating panel


46


by means of which folding parameters and correction values can be entered into the process computer


44


, which takes account of the same upon actuation of the actuating elements


42


. Examples of controllable actuating elements


42


which can be used are electric spindle drives, linear motors, voice coil drives, hydraulic cylinders or pneumatic cylinders. The buckle plates


24


to


30


are provided, in a known manner, with actuating drives


48


, by means of which the buckle plates can be set in accordance with the desired folding layout.




For the automatic setting of the folding-nip width, first of all the actuating drives


48


of all the buckle plates


24


to


30


are activated by the process computer


44


, in dependence on the desired folding layout, and the buckle plates


24


to


30


are set. At the same time, all the actuating elements


42


acting on the links


33


are activated by the process computer


44


such that the folding rollers


12


to


22


of the individual pairs of folding rollers come into contact with one another, with the result that the width of the folding-roller nip is “0”. In this case, the links


33


are prestressed by the compression springs


38


in the direction of the other folding roller of the pair of folding rollers.




If new folding rollers


12


to


22


are used, the displacement-measuring systems


40


may be adjusted or preset such that the displacement measured for the deflection of the link


33


is “0”. The value “0” is used as reference value. If, during a subsequent automatic setting of the folding-roller nip, the deflection measured is greater than or less than 0 when the folding rollers are brought into contact, it can be established, as a result, that the folding rollers are either worn or contaminated.




For automatic setting of the folding-nip width, a sheet is introduced between the first pair of folding rollers


12


,


14


and passes through the buckle folder


10


in accordance with the desired folding layout. In this case, the individual adjustable folding rollers


14


to


22


are deflected in accordance with the sheet thickness. This deflection corresponds to the width of the folding-roller nip which is optimal for processing following sheets. The deflection is measured in each case by the displacement-measuring system


40


and a corresponding measured value is passed on to the process computer. Thereupon, the process computer


44


controls the actuating elements


42


such that the deflection measured by the displacement-measuring system beforehand during first sheet passage is set. If appropriate, it is possible to enter correction values via the keyboard


46


. This optimizes all the folding-roller nips for the passage of further sheets through the buckle folder


10


.




A set value which has been determined by a sample sheet (1st sheet) forms a desired value for the roller-nip setting. This desired value may be compared continuously, in the production process, with the current actual value, as a result of which it is possible for changes in the folding-roller nip (e.g. by roller contamination, roller wear, change in paper thickness) to be established, and indicated, immediately in the production process.



Claims
  • 1. Method of setting a folding-nip width of a plurality of pairs of folding rollers which are provided on a folding machine, each pair of folding rollers including at least one adjustable folding roller, comprising the following steps:the two folding rollers of said plurality of pairs of folding rollers are brought into contact with one another, a sheet is passed between said two folding rollers of said plurality of pairs of folding rollers, whereby said at least one adjustable folding roller moves in relation to the other, so that a folding nip is formed, a value corresponding to said folding-nip width being detected for each of said plurality of pairs of folding rollers as said sheet is passed therebetween, and said folding-nip widths of said each pair of said plurality of pairs of folding rollers is set by adjustment of said at least one adjustable folding roller by means of a drive, which is connected kinematically thereto, based on the corresponding detected value which has been detected for the corresponding pair of folding rollers.
  • 2. Method according to claim 1, wherein properties of a selected folding layout are taken into account during said setting.
  • 3. Method according to claim 1, wherein said values which have been detected are compared with previously determined reference values in order to determine roller wear or roller contamination.
  • 4. Method according to claim 1, wherein said folding rollers are brought into contact with one another by means of said drive, which is connected kinematically to at least one folding roller.
Priority Claims (1)
Number Date Country Kind
01129502 Dec 2001 EP
US Referenced Citations (7)
Number Name Date Kind
4099710 Boyer et al. Jul 1978 A
4125254 Boyer Nov 1978 A
5242364 Lehmann Sep 1993 A
5683338 Krasuski et al. Nov 1997 A
5980439 Johnson et al. Nov 1999 A
6024682 Mandel et al. Feb 2000 A
6206816 Cook et al. Mar 2001 B1
Foreign Referenced Citations (2)
Number Date Country
298 20 796 Feb 1999 DE
0 511 488 Nov 1992 EP