US3623721A - Means for overcoming fan-out in lithographic press - Google Patents

Means for overcoming fan-out in lithographic press Download PDF

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Publication number
US3623721A
US3623721A US869565A US3623721DA US3623721A US 3623721 A US3623721 A US 3623721A US 869565 A US869565 A US 869565A US 3623721D A US3623721D A US 3623721DA US 3623721 A US3623721 A US 3623721A
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United States
Prior art keywords
sheet
stops
pads
transfer assembly
leading edge
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Expired - Lifetime
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US869565A
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English (en)
Inventor
Walter S Smith
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Boeing North American Inc
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North American Rockwell Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F21/00—Devices for conveying sheets through printing apparatus or machines
    • B41F21/04—Grippers
    • B41F21/05—In-feed grippers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H9/00—Registering, e.g. orientating, articles; Devices therefor
    • B65H9/06—Movable stops or gauges, e.g. rising and falling front stops

Definitions

  • the pad mounting means is in the form of a pad bar to which all of the pads are secured and which is deformed into bowed shape upon obstruction by the fixed stops.
  • each of the fixed stops is in the form of a lever having a stop surface adjusted by a manually rotated positioning screw and with an overpowered spring effectively in series to protect against damage or breakage in the event a foreign object is interposed.
  • Fan-out is the change in' the lateral dimension of the sheet as it passes through the press, believed to be caused by the absorption of moisture from the dampening units combined with the ironing effect of the cylinders causing the sheet to expand laterally, particularly at the trailing portion. This condition can be largely overcome by imparting an artificial curvature, or bow, to the leading edge of the sheet.
  • One common expedient for bowing the leading edge is to arrange the front register guides in a bowed configuration and to force the sheet into conformation with the guides.
  • an object of the present invention to provide an infeed mechanism for a sheet-fed press in which the degree of bowing is achieved with precision and consistency without risk of marking or other damage to the sheet and which permits the degree of bowing to be varied to achieve exact register with the press in operation.
  • FIG. 1 is a view in elevation of a transfer assembly constructed in accordance with the invention, in section for the purpose of foreshortening;
  • FIG. 2 is a fragmentary section taken along the line 2-2 in FIG. 1;
  • FIG. 3 is a vertical section taken along the line 3-3 in FIG.
  • FIG. 4 is a fragmentary section based upon FIG. 3 but showing transfer of the sheet to the impression cylinder;
  • FIG. 5 is a section taken along the line 5-5 in FIG. 1;
  • FIG. 6 is a fragmentary section looking along the line 6-6 in FIG. 5;
  • FIG. 7 is a fragmentary section showing a gripper pad and cooperating gripper finger
  • FIG. 8 is a fragmentary section looking along the line 8-8 in FIG. 1;
  • FIG. 9 is a fragmentary section looking along the line 9-9 in FIG. 8;
  • FIG. 10 is a fragmentary section taken along the line 10-10 in FIG. 1;
  • FIG. 11 is a fragmentary section looking along the line 11- II in FIG. 10;
  • FIG. 12 is a fragmentary top view looking along the line 12-12 and showing the cluster of adjusting knobs.
  • FIG. 13 is a fragment showing a pillow on the pad bar as it is swung downwardly from minimum to maximum radius condition incident to obstruction with a stop;
  • FIG. 14 is a diagram of a sheet in contact with the front register guides
  • FIG. 14a is a diagram showing the bowing of the pad bar on striking of the fixed stops.
  • FIG. 14b is a diagram similar to FIG. 14a but showing restoration of the pad bar to straight reference condition to impart reverse bowing to the leading edge of the sheet.
  • FIGS. 1-5 there is disclosed a portion of a sheet-fed lithograph press having a frame [0 and a feed table 11 onto which sheets are fed, one by one, from left to right as viewed in the drawings, against front register stops 13.
  • the latter are mounted upon a shaft 14.
  • a typical sheet, indicated at 15, has a leading edge 16, lateral edges l7, l8, and a trailing edge 19.
  • the front register stops 13 are provided for the purpose of accurately defining the position of the leading edge of the sheet in readiness for transfer in proper phase relation to grippers on a constantly rotating impression cylinder.
  • the front register stops are physically separate from the table'll, and it will be understood that they may be separately adjusted forwardly or backwardly, with respect to the length dimension of the sheet, or skewed slightly as desired.
  • an oscillating transfer assembly 30 For the purpose of picking up a stationary sheet at the leading edge and for accelerating it to press speed, an oscillating transfer assembly 30 is provided including a transversely extending supporting shaft 31 which is mounted for oscillating movement, imparted by arms 32, in frame plates 33 only one of which is shown (FIG. 3) and which in turn are supported upon pedestal structure 34.
  • a stop 35 limits the movement of the transfer assembly and defines its position at the time of pickup.
  • the transfer assembly 30 swings from the position shown in FIG. 3, where the stationary sheet is gripped, to the position shown in FIG. 4, where the sheet has accelerated to press" speed and at which point transfer takes place to a set of grippers 41 mounted upon a constantly rotating impression cylinder 40, following which the transfer assembly decelerates and reverses its movement to return to the pickup position shown in FIG. 3.
  • the means for oscillating the shaft 31 are not included within the scope of the present invention and reference may be made to the prior art for typical oscillating drives such, for example, as that shown in prior U.S. Pat. No. 1,764,104.
  • a plurality of gripper pads are provided on the transfer assembly, each of the gripper pads having gripper pad mounting means biased against reference stops on the transfer assembly so as to normally occupy an aligned reference position but having provision for a small amount of retreating movement.
  • Mounted on the frame in the path of movement of the gripper pad mounting means are a series of fixed but differentially adjustable stops so arranged that when the stops are encountered the gripper pads are moved out of aligned position to an arcuate or bowed locus for gripping the leading edge of the sheet, thereby imparting a bow of opposite curvature to the leading edge of the sheet when the transfer assembly swings away from the fixed stops and as the gripper pad mounting means resumes a condition of alignment determined by the reference stops.
  • a plurality of gripper pads are provided mounted along a gripper pad bar which is normally straight, biased to a reference position, but which is mounted for localized retreating movement with respect to the transfer assembly so that, upon engaging the adjusted configuration of fixed stops, the gripper pad bar is bowed to hold the gripper pad in correspondingly bowed configuration during the time of gripping.
  • the bar resumes its straight, reference position so as to deform the leading edge of the sheet into a slight bow for the purpose of overcoming fan-out at the trailing edge of the sheet.
  • a gripper pad bar 50 is provided having bolted, or otherwise secured along its length, gripper pads indicated at 5 155 (see FIGS. I to 3).
  • a gripper pad 51 by way of example (FIG. 7) it has an anchoring portion 56, a sheet engaging pad surface 57 and an angled entry leg 58 for guiding the leading edge 16 of the sheet into position for gripping.
  • a set of gripper fingers 61-65 which are mounted upon a shaft 60.
  • Means, not shown but well understood by those skilled in the art, are provided for imparting rocking movement to the gripper finger shaft 60 for gripping the sheet when the transfer assembly is in the position of pickup shown in FIG.
  • brackets For the purpose of supporting shaft 60, as well as the pad bar 50, for bodily oscillation by shaft 31, a bracket is provided at each end of the shaft. Such brackets, bifurcated at the lower end, are indicated at 71, 72 in FIGS. 1 and 2. Mounted between the bifurcations at the left-hand end is a supporting lever 73 (see also FIG. having a central opening for admitting the shaft 60 and having a forwardly projecting arm 74 which mounts the bar 50 as well as a rearwardly projecting arm 75. Similarly, at the opposite end of the shaft 60, is a mounting lever 76 mounted between the bifurcations of bracket 72 and having a forwardly projecting arm 77 and a rearwardly projecting am 78.
  • rollers 79 which are engaged by suitable cams so that after the sheet has been deposited in the grippers on the impression cylinder, the pad bar 50 and its associated pads and gripper fingers may be swung inwardly toward the axis of the shaft 31 in an upwardly tucked position so as to avoid interference with elements on the impression cylinder or interference with the trailing portion of the sheet during the return movement of the transfer assembly.
  • the specific cam surfaces for acting upon the rollers 79 are outside of the scope of the present invention and, except as will be discussed in connection with FIG. 13, the position of the pad bar 50, with respect to the oscillating support shaft 31, may be assumed to be defined by a set of limit stops indicated at 80 in FIG. 5.
  • a bracket 91 is mounted upon the shaft 31 in supporting engagement with shaft 60. Straddling the lower end of bracket 91 is a forwardly extending arm 92 of clevis shape having a transverse opening for receiving the shaft 60.
  • a second bracket 93 (FIG. 2) secured to the shaft 31 provides support for shaft 60 and has an arm 94 of clevis shape similar to arm 92.
  • the bar 50 is supported at its ends upon arms 74, 77 and is supported centrally upon evenly spaced arms 92, 94.
  • a square spacer 104 Surrounding the shank of the bolt 101 is a square spacer 104 having a length L which is somewhat greater than the thickness W of the bar 50, thereby to define a clearance space 105 behind the bar. It might be mentioned, also that the square spacer 104, instead of directly engaging the surfaces in the bar, engages a square opening cut into an annular insert 106 which is provided for antiwear purposes. For urging the engaged end of the bar 50 into a normal seated position against the reference stop surface 103, on the backside of the washer, a pair of springs 107, 108 are provided.
  • springs are conveniently recessed into the arm 74 and, while appearing of relatively light construction, are nevertheless sufficiently strong to keep the bar seated on the reference surface until intentional unseating by the adjacent striking of a fixed stop.
  • a pin 109 is provided which is force fitted into the arm 74 and which has a flat formed on its upper side as a bearing surface.
  • FIG. 10 which shows the structure along the section line 10-l0
  • FIG. 11 which is based thereon, corresponding parts are indicated by corresponding reference numerals with the addition of subscript a.
  • a spacer 104a surrounding a bolt 1010 provides clearance a, with the bar being pressed against the reference surface 103a, on the backside of the washer, by biasing springs 107a, 108a.
  • the pad bar is supported by a bolt 101C and the construction is a substantial duplicate of that previously described in connection with FIGS. 5 and 6.
  • the inserts 106 are machined out to provide lateral clearance as indicated at 110 in FIG. 6 and as indicated at 110a in FIG. 1 1.
  • No side clearance is however provided for spacer 104b in FIGS. 8 and 9.
  • lateral clearance is provided adjacent the spacer but on the right-hand instead of the left-hand side.
  • fixed stops are provided adjacent the respective ends of the pad bar 50 for the purpose of engaging the pad bar and to deform the locus of the pads into arcuate or bowed shape as described.
  • a typical one of the fixed, but adjustable stop structures is shown in FIG. 3, as viewed along section line 3-3 in FIG. 1.
  • the stop is in the form of the stop lever having a lower or stop arm 121 and an upper or positionable arm 122, the lever, overall, being of dogleg shape and centrally pivoted at a horizontal pin 123.
  • the ends of the pin 123 are mounted in a vertical bracket 124 having spaced walls secured to a transversely extending bridging member 125 of fairly massive hollow construction.
  • the bridging member 125 is rigidly mounted on brackets 126 at the respective ends thereof, the brackets being secured to side plates 33 mounted on pedestals 34 previously referred to.
  • a manually operated positioning screw 130 is provided which is threaded as indicated at 131 and which has an adjusting knob 132 which in turned backwardly or forwardly to position the tip 133 which engages the backside of the portion 122 of the stop member.
  • a strong spring 135 is interposed between the lower end of the stop member and the frame 124 in which it is mounted. The spring is effectively preloaded so that it is strong enough not to yield in the face of normally developed impact pressure but yieldable in the event that a foreign object should for some reason become interposed between the stop and the bar.
  • the bar has secured thereto a pillow block 136 of progressive thickness to achieve final consuming action.
  • the bar 50 in addition to its oscillatory swinging movement is rocked upwardly about the center of the shaft 60 (see FIG. 5) in timed relation to the bodily movement to provide clearance.
  • the bar is tucked upwardly.
  • the final movement of the pad bar is movement radially downward from the shaft 31 as the fixed stop 120 is engaged and just prior to gripping the leading edge of the sheet. During such downward movement, the stop 120 is engaged first at a radius r1.
  • Corresponding stop structure is provided at two other stop positions, one at the center and the other at the opposite end of the pad bar.
  • a stop lever 120a is used having an upper portion 122a, and pivoted about a horizontal pin 123a mounted in a vertical frame 1240, which is secured to the bridging member 125.
  • an adjusting screw 130a is provided having a thread 131a and a tip 133a.
  • an auxiliary shaft 136 is provided in a more accessible location (see FIG. 12), the two shafts being coupled together by a sprocket chain 137 trained about sprockets 138, I39.
  • a similar fixed stop assembly is provided with corresponding reference numerals for identification with the addition of subscript b.
  • a stop 120b is used having an upper portion l22b and mounted in a frame or bracket 12 3b for engagement by an adjusting screw 13% having a thread 1311b and a knob l32b.
  • the knob is mounted on a shaft 13612 (FIG. 12) which is coupled to the shaft 13% by a sprocket chain 1137b trained around sprockets 138b, I39b.
  • the threads 13!, 131a, and 13112 are preferably left-hand threads for psychological purposes, so that right-hand rotation of the knob is effective to advance the stops incrementally into obstructing position.
  • the adjusting knobs are not only grouped for easy access, but they may be provided with calibrated scales for directly indicating the position of the stops which they are associated. Because of the relatively massive nature of the fixed stop mechanisms, the stops and their associated linkages may be expected to retain calibration with a high order of accuracy over a long press lift.
  • a sheet 15 is fed onto the feed table 11 into contact with front register guides 13. It will be assumed that the sheet, being subject to fan-out, has a fan-out dimension, corresponding to the distance between the side edges 17, 18. It will be assumed further that the desired width of the sheet, for accurate register, corresponds to that between the dot-dash outline 17a, 18a.
  • the pad bar When the transfer assembly is bodily swung to its pick-up position, defined by stop 35, and illustrated in FIG. 3 and FIG. 14a, the pad bar is engaged by the fixed tops 120, 12012 in the two end positions, causing the pad bar to bent away from the reference surfaces into arcuate or bowed shape against the restoring force of the bar and the associated biasing springs.
  • the central stop 120a may be completely backed off. With the pads formed into a bowed locus, the sheet is clamped from the underside against the roughened pad surfaces 57 by fingers 61.
  • the front register guides swing downwardly to clear of the edge of the sheet.
  • the pad bar 50 leaves the fixed stops pennitting the bar to return to its straight reference position illustrated in FIG. 14b.
  • the pads being roughened, carry with them the leading edge portion of the sheet during the restoring movement, imparting a bow of opposite curvature to the leading edge 16 of the sheet and with relative slippage taking place at the smooth-surfaced gripper fingers.
  • the width dimensions between 17, 18 and 17a, 18a now correspond, as shown in 14b, to compensate for, and overcome, the tendency toward fan-out.
  • the bowed shape of the leading edge is retained by the grippers in the impression cylinders following the transfer.
  • stops 120, 120a and 120k are shown as levers of the first class it will be apparent to one skilled in the art that, with slight modification of the structure, levers of the second or third class could be used as well.
  • each pad has a roughened surface and each cooperating gripper finger has a smooth surface to permit relative movement between the sheet and the gripper incident to restorative movement of the pad mounting means to reference position as bowing is imparting to the leading edge of the sheet.
  • An infeed mechanism for a rotary sheet-fed printing press for feeding sheets to grippers on a constantly rotating cylinder comprising, in combination, a frame including a feed table for receiving sheets fed bone by one, set of front register guides for engaging and positioning the leading edge of the advancing sheet, a transfer assembly having means for oscillating the same for picking up the leading edge of the sheet at the register guides and for accelerating the sheet to press speed for transfer to the grippers on the rotating cylinder, said transfer assembly including an axially extending pad bar having a plurality of gripper pads mounted thereon, the pads having respective coacting gripper fingers, means including reference stops on the transfer assembly for establishing a reference position for the bar with respect to the assembly while permitting localized retreating movement away from reference position, means for biasing the pad bar against the reference stops, means for defining the limit of movement of the transfer assembly, a pair of fixed but adjustable stops on the frame in the path of movement of the respective ends of the pad bar, the pad bar being of relatively thin construction so that upon the ends thereof encountering the fixed stops the
  • An infeed gripper mechanism for a rotary sheet-fed printing press for feeding sheets to grippers on a constantly rotating cylinder comprising, in combination, a frame including a feed table for receiving sheets fed one by one, a set of front register guides for engaging and positioning the leading edge of the advancing sheet, a transfer assembly having means for oscillating the same for picking up the leading edge of the sheet at the register guides and for accelerating the sheet to press speed of transfer to the grippers on the rotating cylinder, said transfer assembly including a plurality of gripper pads having mounting means supported on the assembly, the gripper pads having respective coacting gripper fingers, means including reference stops on the transfer assembly for establishing an aligned reference position for the pads while permitting a small amount of localized retreating movement away from the reference position, biasing springs on the transfer assembly for biasing the pad mounting means against the reference stops, means for defining the limit of movement of the transfer assembly, and a series of fixed but adjustable stops on the frame in the path of movement of the pad mounting means, each of said fixed but adjustable stops having a
  • each of the fixed stops has a preloaded spring effectively connected in series for maintaining the stop in its manually adjusted position but capable of yielding in the event a foreign object becomes interposed between the fixed stop and the pad mounting means.
  • each of the fixed stops is in the form of a lever having a stop surface at one end and a threaded manually operated positioning screw at the other end and including a strong spring for maintaining the lever seated with respect to the screw during normal operation of the stop but which is capable of yielding upon interposition of a foreign object at the stop surface.
  • An infeed mechanism for transferring sheets from a position of rest on a support to grippers ona constantly rotating cylinder comprising an oscillatable transfer assembly having a series of gripper fingers and coacting pads for gripping a sheet on said support, accelerating the sheet to cylinder speed and transferring the sheet to the cylinder grippers, mounting means for said pads including an axially extending resilient member for normally maintaining the pads in a reference plane extending transverse to the path of the sheets, means for oscillating the transfer assembly between a sheet engaging position with respect to said support and a transfer point with respect to the cylinder, adjustable stop means located in the path of said resilient member adjacent said support, said stop means being adjustable to intercept and variably displace local portions of the resilient member from the reference plane while the transfer assembly is in the sheet engaging position to thereby temporarily displace the pads into the locus of a bow, and means for actuating the gripper fingers to grip a sheet while the pads are so displaced so that a predetermined bow is imparted to the leading edge of the sheet as the pads return to said
  • An infeed mechanism for a rotary, sheet-fed printing press comprising in combination, an oscillatable transfer assembly having a series of gripper pads and coacting gripper fingers for gripping the leading edge of a sheet at rest on a feed table and accelerating said sheet to press speed for transfer to grippers on a constantly rotating cylinder, means for oscillating the transfer assembly between a sheet gripping position adjacent the feed table and a sheet transfer position adjacent the cylinder, means mounting said gripper pads on the transfer assembly including an axially disposed flexible bar for normally maintaining the pads in a predetermined reference plane extending transverse to the path of the sheets, at least one fixed but adjustable stop located in the path of said bar adjacent the feed table, said stop being adjustable to intercept and variably displace a local portion of said bar from the said reference plane as the transfer assembly moves to the sheet gripping position to thereby temporarily place the gripper pads thereon in the locus of a bow, and means for actuating the gripper fingers to grip the leading edge of a sheet while the gripper pads are so displaced so that

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  • Feeding Of Articles By Means Other Than Belts Or Rollers (AREA)
  • Supply, Installation And Extraction Of Printed Sheets Or Plates (AREA)
US869565A 1969-10-27 1969-10-27 Means for overcoming fan-out in lithographic press Expired - Lifetime US3623721A (en)

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US86956569A 1969-10-27 1969-10-27

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US3623721A true US3623721A (en) 1971-11-30

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US (1) US3623721A (enrdf_load_stackoverflow)
JP (1) JPS495925B1 (enrdf_load_stackoverflow)
CH (1) CH530867A (enrdf_load_stackoverflow)
FR (1) FR2066812A5 (enrdf_load_stackoverflow)
GB (1) GB1257447A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3833213A (en) * 1972-04-17 1974-09-03 Rockwell International Corp Means for overcoming fan-out in lithograph press
US5176079A (en) * 1988-12-03 1993-01-05 Heidelberger Druckmaschinen Ag Device for correcting the register of sheet overprints in a sheet-fed rotary printing machine
US5651544A (en) * 1995-02-04 1997-07-29 Heidelberger Druckmaschinen Ag Device for avoiding registration errors in a sheet-processing machine

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2503631A1 (fr) * 1981-04-10 1982-10-15 Billot Lucien Dispositif de rectification frontale pour machine d'impression offset
DE9409890U1 (de) * 1994-06-18 1994-08-04 Heidelberger Druckmaschinen Ag, 69115 Heidelberg Vorrichtung zur Passerkorrektur an Bogenrotationsdruckmaschinen

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2577099A (en) * 1946-06-14 1951-12-04 Hoe & Co R Method of and means for registering impressions in multiunit sheet printing machines
US2642283A (en) * 1949-07-01 1953-06-16 Hoe & Co R Sheet registering mechanism

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2577099A (en) * 1946-06-14 1951-12-04 Hoe & Co R Method of and means for registering impressions in multiunit sheet printing machines
US2642283A (en) * 1949-07-01 1953-06-16 Hoe & Co R Sheet registering mechanism

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3833213A (en) * 1972-04-17 1974-09-03 Rockwell International Corp Means for overcoming fan-out in lithograph press
US5176079A (en) * 1988-12-03 1993-01-05 Heidelberger Druckmaschinen Ag Device for correcting the register of sheet overprints in a sheet-fed rotary printing machine
US5651544A (en) * 1995-02-04 1997-07-29 Heidelberger Druckmaschinen Ag Device for avoiding registration errors in a sheet-processing machine

Also Published As

Publication number Publication date
JPS495925B1 (enrdf_load_stackoverflow) 1974-02-09
FR2066812A5 (enrdf_load_stackoverflow) 1971-08-06
GB1257447A (enrdf_load_stackoverflow) 1971-12-15
CH530867A (de) 1972-11-30

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