EP0057078A2 - Vorrichtung zum Befestigen einer Druckplatte auf einem Druckzylinder - Google Patents

Vorrichtung zum Befestigen einer Druckplatte auf einem Druckzylinder Download PDF

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Publication number
EP0057078A2
EP0057078A2 EP82300253A EP82300253A EP0057078A2 EP 0057078 A2 EP0057078 A2 EP 0057078A2 EP 82300253 A EP82300253 A EP 82300253A EP 82300253 A EP82300253 A EP 82300253A EP 0057078 A2 EP0057078 A2 EP 0057078A2
Authority
EP
European Patent Office
Prior art keywords
locking
cylinder
printing plate
printing
plate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP82300253A
Other languages
English (en)
French (fr)
Other versions
EP0057078A3 (de
Inventor
Kevin Graham Davies
John Richard Marsh
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Auto Masters Ltd
Original Assignee
Auto Masters Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Auto Masters Ltd filed Critical Auto Masters Ltd
Publication of EP0057078A2 publication Critical patent/EP0057078A2/de
Publication of EP0057078A3 publication Critical patent/EP0057078A3/de
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41L—APPARATUS OR DEVICES FOR MANIFOLDING, DUPLICATING OR PRINTING FOR OFFICE OR OTHER COMMERCIAL PURPOSES; ADDRESSING MACHINES OR LIKE SERIES-PRINTING MACHINES
    • B41L29/00—Devices for attaching printing elements or formes to supports
    • B41L29/12—Devices for attaching printing elements or formes to supports for attaching flexible printing formes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F27/00—Devices for attaching printing elements or formes to supports
    • B41F27/12—Devices for attaching printing elements or formes to supports for attaching flexible printing formes
    • B41F27/1218—Devices for attaching printing elements or formes to supports for attaching flexible printing formes comprising printing plate tensioning devices
    • B41F27/125—Devices for attaching printing elements or formes to supports for attaching flexible printing formes comprising printing plate tensioning devices moving in the printing plate end on a curvilinear path, e.g. by winding on a roll

Definitions

  • the present invention relates to a mechanism for securing a flexible printing plate to a printing cylinder.
  • such printing plates are made of thin aluminium or mild steel sheets and attached either directly to a shim of a printing cylinder or to a saddle which is itself attached to the cylinder.
  • the securement mechanism therefor comprises a simple retaining means at the leading edge of the plate, as considered in the direction of rotation of the cylinder, and a tensioning means at the trailing edge of the plate.
  • the tensioning means used in the past have made use of a rotary locking bar having a plurality of projections therealong which engage in holes made in the plate. Rotation of the bar by a tool after-engage- ment with the plate tensions the plate pulling it tight against the surface of the shim or the saddle of the printing cylindar.
  • the printing plate tensioning assembly may be detachably attached directly to the outer cylindrical surface of the printing cylinder between facing edge portions of the shims, as described in U.K. Patent 1 575 016 by K + F Manufacturing Co. Inc.
  • the tensioning means of the securement mechanism is mounted on the trailing edge of the saddle.
  • An object of the present invention is to provide an improved mechanism for securing a printing plate to a printing cylinder, which mechanism is suitable for use both with paper and plastics plates, and with metallic sheet plates.
  • apparatus for securing a flexible printing plate to a printing cylinder comprising holding means for holding one edge of the plate on. the cylinder, locking means including a pivotally mounted body adapted.to engage the opposite edge of the printing plate and pivotal in use between a locking position in which the printing plate is locked under tension on the cylinder and a release position in which the printing plate can bo fitted or removed, and biasinc means having over-centre action spring means which to the locking side of an intermediate position of the body urge the body into the locking position and to the release side of said intermediate position urge the body into tha release position.
  • apparatus for occuring a flexible printing plate to a printing cylinder comprising holding means for holding one edge of the plate on the cylinder, locking means including a body pivotally mounted for selective pivotal movement from a central release position to a locking position at either side of the release position depending upon the direction of rotation of the printing cylinder, the body being adapted to engage the opposite edge of the printing plate so as to lock the printing plate under tension on the cylinder in the selected locking position and permit fitting or removal of the plate in the release position, and biasing means with over-centre action spring means having a stable intermediate or neutral position at the central release position Whereby deflection to either side of the intermediate position causes the spring means to urge the body into the corresponding locking position.
  • the body includes a spindle with exposed journal sectibns engaged by complementary bearing formations of the mounting means for the body.
  • the spring means may comprise respective springs acting on the spindle from opposite sides thereof so as to define said stable intermediate or neutral position when the springs act to neutralise each'other and to exert a turning force on the spindle on deflection out of said neutral position theroby urging the body into the corresponding locking position.
  • the drawings show a printing cylinder 1, which is rotatable, in use, in the diroction shown by arrow 2 and which is provided uith a pair of saddles 3 to each of Which a printing plate 4 can be attached by a locking mechanism according to the present invention.
  • the locking mechanism comprises holding means 5 which is located along the leading edge 6 of the saddle 3 with respect to the direction of rotation of the cylinder 1.
  • the holding means 5 comprises a simple clamp arrangement in which the edge 6 of the saddle 3 is undercut to provide an acute angle 7.
  • Attached to the saddle 3 along the edge 6 is a metal or plastics strip 8 which is formed so as to define a clip with the edge G. In this way, one edge 9 of the printing plate 4 can be retained by being pushed firmly between the strip 8 and the edge 6 so that the strip 8 clamps the plate 4 to the edge 6 and the plate 4 folds over the angle 7 against the surface 10 of the saddle 3.
  • the locking mechanism comprises a locking arrangement 12 to hold and tension the trailing edge 13 of the printing plate 4 opposing the leading edge 9 thereof against the surface 10 of the saddle.
  • the arrangement 12 comprises a locking member 14 with a body having a heel 15 of part-circular profile.
  • the trailing edge 11 of the saddle 3 is also formed with a part-circular profile, into which the heel 15 of the member 14 fits so that the locking member 14 has a degree of rotary motion with respect to the saddle 3 and thereby the cylinder 1.
  • the locking member 14 is-retained in position with respect to the saddle 3 by two hinges at opposite sides of the saddle only one of Which is shown in Fig. 1.
  • the locking member body is made of sheet metal strip bent into shape with a spindle 16 inserted and secured- thereto by suitable means (not shown).
  • the curved heel 15 passes into side walls 17, 18 which defines therebetween a retaining groove 19 for the trailing edge 13 of the printing plate 4.
  • the retaining groove 19 has a parallel-sided section 20 leading into a flared mouth 21 facilitating entry of the printing plate edge. That side wall 18 which is nearer to the associated holding means 5 is shorter than the other side wall 17 for the same reason.
  • the body of the locking member ha3 cut-outs 22, 23 exposing reduced diameter sections 24, 25 of the spindle 16 Which provide journals for hooked ends 26, 27 of a hinge element 28.
  • a generally circular split spring 29 is retained by the hinge element 28 and abuts With its one end against a lip 30 of the hinge element 28.
  • the opposite end of the spring 29 has a U-shaped projection 31 of which the cross-piece 31a seats in a groove 32 in the body.
  • the groove 32 has circumferential extensions 32a, b at each end for receiving the side pieces 31b, c of the spring projection 31 when necessary.
  • the hinge element 28 is secured in a recess 33 at the trailing edge of the saddle 3 by means of screws 34, 35 extending through apertures 36, 37 in the hinge elenent 28 into engagement with tapped holes 38, 39 in the saddle 3.
  • the recess 33 is U-shaped leaving an island of material 40 at the edge of the saddle 3 which is thus weakened little-if at all by the two recesses in its trailing edge.
  • the hinge element 28 has a cut-out 41 which fits over the island 40. It will be appreciated that the hinge at the opposide side of the saddle is constructed in the same way.
  • the construction of the hinges is such that the springs 29 have an over-centre action with respect to an unstable intermediate or neutral position which occurs when the line of action of each spring 29 is in line with the slot 32 and the axis of rotation of the body.
  • the springs act to urge the body in the same direction i.e. towards the locking or release position.
  • the spindle 16 has a flat surface 42 along one side thereof so as to provide an extension of the groove 19 (Figs. 3 to 5).
  • the reduced diameter sections 24, 25 of the spindle 16 lie radially within the flat surface 42 so as to permit engagement by the hooked ends 26, 27 without obstructing the groove 19.
  • Fig. 3 shows the locking member 14 in the release psition ready for receiving the trailing edge 13 of a printing plate 4.
  • the holding means 5 is about to receive the leading edge 9 of what may be assumed for the purposes of illustration to be the same printing plate 4. It will be seen that the locking member 14 projects generally radially with respect to the cylinder 1 and well above the surface 10 of the saddle 3 thus permitting a relatively deep retaining groove 19 which is increased in depth by the flat surface 42 on the spindle 16. Because of the depth of the groove 19 the trailing edge 13 is retained therein without any nipping or clamping action by the walls 17, 18 but merely by friction with the sides of the groove as the locking member 14 is turned into the fully locked position shoun
  • the printing plate 4 is fitted to the saddle 3 by inserting the leading edge 9 in the direction of the arrow in Fig. 3 into the nip defined by the edge 6 of the saddle 3 and the clamping strip 8.
  • the trailing cdge 13 of the plate 4 is then inserted into the retaining groove 19 of the locking member 14 which is held in the release position by spring pressure urging the locking member 14 into abutment with the edge of the saddle. The operator can thus use both hands to fit the trailing edge 13 into the retaining groove 19.
  • Fig. 4 shows both leading and trailing edges 9, 13 of the printing plate 4 fully inserted and finger pressure being used to push the locking member 14 towards the locking position.
  • the neutral or intermediate position of the over-centre springs is closely adjacent to the release position of the locking member 14 so that only a small rotational movement is required to push the locking member past the neutral position, i.e. over-centre, whereupon the springs snap the locking member 14 into the locking position (Fig. 5).
  • the angular movement of the locking member 14 between the release and locking positions is approximately 90° and in the locking position the locking member 14 is more or less tangential to the printing cylinder 1.
  • the exact amount of movement will depend upon the length of the printing plate 4 and slight variations in this dimension will produce corresponding changes in the angular orientation of the locking member 14 inthe locking position. It is important that the printing plate 4 should aluays hold the locking member 14 out of direct contact with the printing cylinder 1 in the locking position for otheruise insufficient tension is exerted on the plate.
  • the locking member 14 When it is desired to remove the printing plate 4 from the cylinder 1, the locking member 14 is then rotated from the locking position (Fig. 5) back to the release position (Fig. 3) and the trailing edge 13 of the plate 4 removed from the mouth 21. The leading edge 9 of the plate 4 can then be removed by pulling from the holding means 5. It is possible to rotate the locking member 14 back into the release position by hand. However, as in practice it is aukuard to grasp the locking member 14 with fingers often owing to the proximity of the leading edge of the adjacent saddle 3, a tool (not shoun) may be used. Such a tool conveniently comprises an angled strip, the turned over angle portion of uhich can be engaged in the mouth 21 and the tool pulled to raise the member 14 back into the release position.
  • the advantage of having a locking member 14 which is movable at least from the first position into the second position by hand is twofold. Firstly, it permits the person fitting the plate 4 on the cylinder 1 to use both hands in the location of the trailing edge 13 of the plate 4 in the mouth 21 as the edge 13 can be held in the mouth 21 whilst pushing the member 14 over into the second position. This is in contrast to prior art arrangements uherein a tool is required to rotate the equivalent lorking bar and only one hand can be used to hald the plate in the appropriate position with respect to the locking bar.
  • the comparative ease with which the locking member 14 rotates and the proximity of the centre position of the biasing springs to the release position prevent damage if the locking member 14 is accidentally left in the release position when the cylinder 1 is used. If this happens, the locking member 14 is automatically rotated into the locking position by contact with a cooperating press roller or cylinder.
  • the accidental use of a cylinder having an incorrectly positioned locking bar results in damage to the paper as the locking bar remains in the wrong position during printing.
  • the embodiment of locking mechanism described above is saddle-mounted and cannot be used without reversing saddles when the direction of rotation of the printing cylinder 1 is reversed.
  • the embodiment of Figs. 6 and 7 is cylinder-mounted and can be used without modification independently, of the-direction of rotation of the cylinder.
  • parts which correspond to those of the first embodiment are designated by the same reference numeral increased by 100.
  • the cylinder 101 is fitted with shims 103 which contrast with the saddles 3 by being attached directly to the cylinder and having no mechanisms attached to their leading and trailing edges.
  • the facing edges 106 of the shims 103 are undercut and define therebetween a recess 150 which receives a locking member 114 pivotally mounted on a base 151 which is detachably attached directly to the cylinder 101 by means of screws 152 locating in slots 153 permitting some lengthwise adjustment of the locking member 114 prior to final tightening.
  • the base 151 has upturned side edges 154 and 155 and centrally arranged, spaced bearing portions 156 alternating with cut-outs 157.
  • the locking member 114 has corresponding body sections 158 and cut-away portions 159 which interengage With the bearing portions 156 and cut-outs 157 of the base 151 as shown in Fig. 6.
  • the locking member 114 and the base 151 are interconnected by the spindle 116 which is then fixed to the body of the locking member 114.
  • the spindle 116 provides journals for the bearing portions 156 of the base 153.
  • the retaining groove 119 of the locking member 114 is defined by the body side walls 117, 118 which in this case are of equal length.
  • the mouth 121 is flared as previously but the spindle 116 is not provided with a flat surface serving to increase the depth of the groove 119.
  • the over-centre spring means for the second embodiment is illustrated in Fig. 7.
  • Each spring 129 has a straight section 150 which locates in the respective sido edge 154, 1 55 of the base 151.
  • Converging legs 161, 1 62 extend from the straight section 160 to hooked ends 163, 164 which engage in respective grooves in the spindlo 116 through openings 165, 166 in the body.
  • Each spring 129 has an exactly similar spring 129 arranged opposite it at the other side of the locking member 114 as shown in dotted line in Fig. 7. In Figs.
  • the locking member is shown in the upright or relase position ready for receiving the trailing edge of a printing plate 4 supported on the shim 103 to the right or left of the recess 150 depending upon the direction of rotation of the printing cylinder 101.
  • This position is a stable neutral or intermediate position in which-the turning force exerted by e pair of springs 129 at one side of the locking member 114 is balanced by the turning force exerted by the pair of springs at the opposite side of the locking member 114. If the locking member 114 is now deflected in either direction out of this central position the springs 129 at both sides act to urge the locking member 114 in that direction into a locking position in which the locking member 114 is approximately tangential to the cylinder 101.
  • the hooked ends 163, 164 of one spring 129 will act in one direction above the axis of rotation of the body and the hooked ends 163, 164 of the opposing spring 129 will act in the opposite direction below the axis of rotation of the body.
  • the level of action of the springs is reversed. It will be appreciated that for any particular direction of rotation of the printing cylinder 1, only the release position and the locking position to one side of the locking member 114 will be used. For example, in Fig. 6, if the cylinder is rotated clockwise the locking position to the left-hand side of the release position will be used. If the direction of rotation of the cylinder is then reversed the locking position at the opposite side is used.
  • the manner of retention of the trailing edge of the printing plate in the retaining groove 119 is the seme as in the first embodiment.
  • the locking member 114 as seen in the release position again projects well above the outer surface of the shims 103 in order to permit relatively great depth of the retaining groove 119.
  • the leading edge of the printing plate may be engaged by the undercut edge 106 of the shim 103 cooperating with a spring member, e.g. as in Figs. 4 and 5, or possibly without the use of a special clamping member as shown.
  • the locking member 14 is used to replace the locking bar arrangements of existing printing cylinders end the holding means 5 can be included in a screu- on strip which can be added to the saddle or shim of the existing machine.
  • the construction of the helding means may be different and instead or a clip arrangement or an undercut edge may comprise a slotted mouth cut into the leading edge of the saddle or shin at an acute angle to the surface.
  • the locking mechanism when the locking mechanism is cylinder-mounted as shown in Figs. 6 and 7 it is possible to provide for only one locking position at the trailing side of the release position of the locking member.
  • the biasing springs will act in the same uay as in the first ambodimen with the unstable neutral position adjacent the upright release position.
  • two such locking members may be provided in each recess 150 to permit rotation of the printing cylinder in opposite directions, ane of the locking members being used when the cylinder is rotated in one direction and the other locking member being used when the cylinder is rotated in the opposite direction.
  • the locking member instead of being mounted on a saddle or directly on the cylinder it is possible for the locking member to be mounted in the recess between two shims on a support uhich is detachably mounted on the confronting edges of the shims.
  • the locking member may have means for locating the trailing edge of the printing plate other up than a retaining groove.
  • a locking bar may bo provided with an undercut trailing edge over which the edge of the printing plate fits, possibly with pins of the locking bar engaging perforations in the plate. See, for example, Figs. 3 and 17 of U.K. Patent 1 575 016 referred to above.

Landscapes

  • Supply, Installation And Extraction Of Printed Sheets Or Plates (AREA)
  • Printing Plates And Materials Therefor (AREA)
EP82300253A 1981-01-23 1982-01-19 Vorrichtung zum Befestigen einer Druckplatte auf einem Druckzylinder Withdrawn EP0057078A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8102041 1981-01-23
GB8102041 1981-01-23

Publications (2)

Publication Number Publication Date
EP0057078A2 true EP0057078A2 (de) 1982-08-04
EP0057078A3 EP0057078A3 (de) 1982-08-18

Family

ID=10519157

Family Applications (2)

Application Number Title Priority Date Filing Date
EP82300254A Expired EP0057530B1 (de) 1981-01-23 1982-01-19 Vorrichtung zum Befestigen einer flexiblen Druckplatte auf einem Druckzylinder
EP82300253A Withdrawn EP0057078A3 (de) 1981-01-23 1982-01-19 Vorrichtung zum Befestigen einer Druckplatte auf einem Druckzylinder

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP82300254A Expired EP0057530B1 (de) 1981-01-23 1982-01-19 Vorrichtung zum Befestigen einer flexiblen Druckplatte auf einem Druckzylinder

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EP (2) EP0057530B1 (de)
AT (1) ATE21652T1 (de)
DE (1) DE3272789D1 (de)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3727551A (en) * 1971-07-22 1973-04-17 North American Rockwell Reversible lockup for flexible printing plate
US3757690A (en) * 1971-08-11 1973-09-11 Polygraph Leipzig Printing plate clamping device
DE2637661A1 (de) * 1975-10-03 1977-04-14 Wifag Maschf Vorrichtung zum aufspannen von biegsamen druckplatten auf eine sattelplatte
GB1575017A (en) * 1975-12-01 1980-09-17 K & F Manufacturing Co Printing plate clamping apparatus

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1178442B (de) * 1960-03-07 1964-09-24 Miehle Goss Dexter Inc Vorrichtung zum Aufspannen von biegsamen Druckplatten auf Formzylinder von Druck-maschinen
AU446576B2 (en) * 1969-07-09 1974-03-08 Baker Perkins Ltd Improved printing plate locking device
US3757691A (en) * 1972-06-12 1973-09-11 North American Rockwell Printing cylinder
GB1403053A (en) * 1972-11-10 1975-08-13 Timsons Ltd Plate mounting means for printing cylinders
DE2759434C3 (de) * 1977-10-01 1981-07-30 Albert-Frankenthal Ag, 6710 Frankenthal Vorrichtung zum Spannen von biegsamen Druckplatten am Formzylinder von Rotationsdruckmaschinen
DE2744371C3 (de) * 1977-10-01 1980-04-10 Albert-Frankenthal Ag, 6710 Frankenthal Vorrichtung zum Befestigen und Spannen von biegsamen Druckplatten

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3727551A (en) * 1971-07-22 1973-04-17 North American Rockwell Reversible lockup for flexible printing plate
US3757690A (en) * 1971-08-11 1973-09-11 Polygraph Leipzig Printing plate clamping device
DE2637661A1 (de) * 1975-10-03 1977-04-14 Wifag Maschf Vorrichtung zum aufspannen von biegsamen druckplatten auf eine sattelplatte
GB1575017A (en) * 1975-12-01 1980-09-17 K & F Manufacturing Co Printing plate clamping apparatus

Also Published As

Publication number Publication date
ATE21652T1 (de) 1986-09-15
EP0057078A3 (de) 1982-08-18
DE3272789D1 (en) 1986-10-02
EP0057530A1 (de) 1982-08-11
EP0057530B1 (de) 1986-08-27

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Inventor name: DAVIES, KEVIN GRAHAM