Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
  • B26D—CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING
  • B26D7/00—Details of apparatus for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting
  • B26D7/01—Means for holding or positioning work
  • B26D7/015—Means for holding or positioning work for sheet material or piles of sheets

Definitions

• the invention relates to method and apparatus for punching register holes in sheet material, this term as used herein relating not only to paper sheets but also to plastics sheets, photographic plates, metal sheets, film and the like used in the graphic industry. Henceforth reference will be made to sheet when sheet material of said kinds is referred to.
• the register holes are used for exact positioning of sheets in a predetermined position when sheets are handled for treatment or use thereof in different ways in lithographic processes. For example, positioning of photographic plates, masks and films in making printing plates for offset printing may be concerned. It is a necessary pre-requisit in order to obtain finally a satisfactory result, for example good register of the colours of a product of multi-colour printing, that the punched register holes are located in an exact predetermined position on the sheet.
• the object of the invention is to replace the manual operation by an automatic operation which with an accuracy unsurpassed so far provides positioning of the sheet in the intended position before punching.
• a method for punching register holes in sheet material wherein the sheet material is positioned on a punching table in relation to fixedly located punches by guidance of adjustment marks on the sheet material, said method having obtained the characterizing features according to claim 1.
• FIG. 1 is plan view of an apparatus according to the invention
• FIG. 2 is a side view of the apparatus in FIG. 1
• FIG. 3 is a perspective view of a punching table with punches and sensors
• FIG. 4 is a diagrammatic plan view of an adjustable section placed on the punching table
• FIG. 5 is a plan view of a sheet with adjustment marks.
• the apparatus shown in FIGS. 1 and 2 comprises a frame 10 having three separate sections, viz. a picking magazine 11, a punching table 12, and a finished product magazine 13.
• the picking magazine 11 has guides 14 which may be adjustable for adjustment to different sheet sizes, and in FIG. 1 there is indicated by dot-and-dash lines 15 a sheet pile in this magazine.
• the finished product magazine 13 has in a corresponding way guides 16, and the sheet pile in this magazine is indicated by dot- and-dash lines 17.
• Two guides 21 are supported by means of flanges 18, 19 and 20 projecting from the frame 10, said guides extending along the frame over the punching table 12 and the finished magazine 13 and over the portion of the picking magazine 11, which is next to the punching table 12.
• Two suction ramps 22 and 23 are displaceably guided on the guides 21 and are connected to linear drive means 24, e.g. a double acting pneumatic ram, to be driven by said means along the guides, fixedly spaced from each other.
• the suction ramps can be displaced by the drive means 24 from the left end position shown in FIGS.
• suction ramp 22 is located over the sheet pile 15 at the right end thereof and the suction ramp 23 is located over a vacuum table 25 at the same level as the puching table 12, at the right end thereof, to a left end position wherein the suction ramp 22 has been dis ⁇ placed to the position where the suction ramp 23 is located in FIG. 1, and the suction ramp 23 has been dis ⁇ placed to the finished product magazine 13 where it is located over the pile 17 at the right end thereof the suction ramp being indicated by dot-and-dash lines 23' in said position.
• the suction ramps can be displaced between these end positions in order that the suction ramp 22 will grip the uppermost sheet of the pile 15 and will pull said sheet onto the punching table 12 and will posi ⁇ tion the sheet over the vacuum table 25 as indicated by dot-and-dash lines 15' .
• the sheet indi- cated on the punching table 12 will be gripped by the suction ramp 23 and will be pulled into the finished pro ⁇ duct magazine 13 to be deposited therein to form together with other sheets transferred to the finished product magazine the pile 17 which thus will comprise punched sheets.
• pressure rollers 26 are mounted in a conventional way in this magazine.
• the vacuum table 25 can be of a conventional con- struction and is constructed to attach a sheet against the plane surface thereof when the vacuum table is put under vacuum, i.e. activated.
• the vacuum table is made adjustable in the punching table 12 so as to be displaced in the direc- tions X and Y indicated by double arrows in FIG. 4, and to be rotated in the direction Z indicated by a double arrow. Said adjustment of the vacuum table can be effected by electric step motors which provide the greatest accuracy in the positioning of the vacuum table.
• On the punching table 12 there is provided adjacent the vacuum table at the longitudinal edges thereof four punch assemblies 27 of conventional type.
• the punching table there are also provided two cameras with the objectives thereof directed downwards towards the punching table, and these cameras form sensors for sensing the position of the sheet located on the punching table 15' by guidance of adjustment marks 29 (FIG. 5), which are found on each sheet in the picking magazine.
• the adjustment marks can be of different types. The marks are shown here as crosses but they can comprise also dots, circles, squares or the like, or combinations thereof.
• the cameras 28 should be connected to a micro ⁇ processor to forward to the microprocessor input signals by guidance of the adjustment marks 29, said input signals indicating the position of the sheet 15 laying on the punching table 12.
• the microprocessor will control the drive means 24 and the step motors connected to the vacuum table 25.
• the programming and construction of microprocessors for the performance of such control can be effected on the basis of common knowledge of the skilled man on the present state of the computer art and accordingly will not be described in more detail here.
• the vacuum ramp 22 has positioned the sheet 15' on the punching table 12 and has returned to the left position shown in FIGS. 1 and 2.
• the positioning of the sheet 15' is controlled from the microprocessor which stops the movement of the sheet onto the punching table 12 when the cameras 28 sense the adjustment marks 29. Then, the sheet 15' can be positioned on the punching table 12 with an accuracy of »1.0 mm, but this accuracy is not satisfactory for punching the sheet and thus a fine adjustment has to take place.
• This fine adjustment of the position of the sheet 15' is obtained by means of the vacuum table 25 which will be activated as soon as the sheet 15' has been positioned on the punching table 12.
• adjustment of the vacuum table 25 and thus of the sheet 15' attached to the vacuum table will be effected via the micro ⁇ processor as required in the directions X, Y and Z in order that the two adjustment marks 29 will be centered below the cameras or in relation to zero marks provided on the positioning table, the positions of the adjustment marks being sensed continuously by the cameras during the positioning by means of the step motors in the directions X, Y and Z.
• This positioning can be performed at an accuracy of »0.01 mm, and when the positioning has been closed the punch assemblies 27 will be activated in dependence of a signal from the micro processor for punching of the sheet.
• the acti ⁇ vation of the vacuum table 25 will be ceased and the drive means 24 will displace the suction ramps 22 and 23 to the right end position for deposition of the punched sheet 15' in the finished product magazine 13 and with ⁇ drawal of a new sheet from the picking magazine 11 for punching on the punching table 12.
• the sensors for sensing the adjustment marks on the sheets can comprise for example inductive, mechanical or other known types of sensors instead of cameras as shown herein.
• the adjustment means for the vacuum table can of course comprise other means then electric step motors, e.g. hydraulic or mechanical adjustment means.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Forests & Forestry (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Perforating, Stamping-Out Or Severing By Means Other Than Cutting (AREA)
• Details Of Cutting Devices (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20383671

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (1)

Citations (6)

• 1991
  • 1991-09-10 SE SE9102602A patent/SE9102602D0/xx unknown
• 1992
  • 1992-09-08 EP EP92925489A patent/EP0603343B1/de not_active Expired - Lifetime
  • 1992-09-08 DE DE0603343T patent/DE603343T1/de active Pending
  • 1992-09-08 DE DE69218443T patent/DE69218443T2/de not_active Expired - Fee Related
  • 1992-09-08 AT AT92925489T patent/ATE150352T1/de not_active IP Right Cessation
  • 1992-09-08 WO PCT/SE1992/000632 patent/WO1993004825A1/en active IP Right Grant
  • 1992-09-08 AU AU25792/92A patent/AU2579292A/en not_active Abandoned

Patent Citations (6)

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