US3537391A - Sheet handling apparatus and method for multicolor perfector press - Google Patents

Description

United States Patent [72] Inventors Harry E. Mowry;

Guy F. Werner, Pittsburgh, Pennsylvania [211 App]. No. 676,188 [22] Filed Oct. 18, 1967 [45] Patented Nov. 3, 1970 [73] Assignee Miller Printing Machinery Co.

Pittsburgh, Pennsylvania a corporation of Pennsylvania [54] SHEET HANDLING APPARATUS AND METHOD FOR MULTI-COLOR PERFECTOR PRESS 12 Claims, 10 Drawing Figs.

Primary Examiner-Robert E. Pulfrey Assistant Examiner.l. Reed Fisher Attorney-Stanley .l. Price,.lr.

ABSTRACT: A sheet fed offset printing press having a perfecting cylinder with suction means disposed longitudinally along the periphery of the cylinder and pairs of tumbler grippers positioned adjacent to the suction means. The suction means is arranged to engage the trailing edge of a sheet on an adjacent impression cylinder and transfer the trailing edge of the sheet to the adjacent pairs of tumbler grippers. The trailing edge of the sheet .is reversed by the tumbler grippers and becomes the leading edge of the sheet. The sheet with the former trailing edge as the leading edge is then transferred to an adjacent impression cylinder. The suction means is mounted for limited rotation along the periphery of the perfecting cylinder to tension the sheet on the adjacent impression cylinder before the sheet is released from the impression cylinder to remove wrinkles present in the sheet. The suction means may also be arranged for limited sliding movement relative to the sheet so that all of the sheets are engaged by the suction means at the same location adjacent the trailing edge of the sheet. The trailing edge of the sheet is engaged by the suction means when the suction means is tangent to the adjacent impression cylinder and transfers the sheet to the first pair of grippers at a location where the tumbler grippers are beyond the tangent point with the first impression cylinder.

With this arrangement, the pair of tumbler grippers can extend beyond the periphery of the perfecting cylinder during transfer of the sheet thereto from the suction means.

Patented Nov. 3, 1970 3,53 7,391

Sheet 1 of 2 mum r095 HARRY 7 MOWR) y our F WERNER ATTORNEYS Patented Nov. 3, 1970 3,537,391

Sheet 2 of 2 l/VVE/VTOAS HARRY .E. MOW/W Z6 cur F? WERNER BK ATTORNEYS SHEET HANDLING APIARATUS AND METHOD FOR MULTI-COLOR PERFECTOR PRESS BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates generally to sheet fed offset printing presses having a perfecting cylinder. More particularly the invention relates to a sheet fed offset printing press wherein the perfecting cylinder has suction means to engage the trailing edge of the sheet and tumbler grippers for engaging the trailing edge of the sheet from the suction means and changing the trailing edge to the leading edge ofthe sheet.

2. Description ofthe Prior Art A sheet fcd rotary printing press adapted to be employed either as a multicolor press or as a perfecting press is known. A comprehensive disclosure ofthis press is found in U.S. Pat. No. 2,757,(il(l granted to Gegcnheimer et al. In this patent a third transfer cylinder or perfecting cylinder receives the sheet from a second impression cylinder after the first printing operation. The third transfer cylinder is designed to receive and transfer the sheet in such a fashion that the second printing will be applied either to the same side of the sheet as the first printing, [.e. multicolor printing or alternatively to reverse the sheet so that the opposite side is presented to the second printing unit, i.e. perfecting printing.

The third transfer cylinder or perfecting cylinder is provided with a series of two-color grippers and a closely adjacent series of perfecting grippers. In the normal direction of rotation of the cylinder, the two-color grippers are disposed behind the perfecting grippers. When the cylinder is employed in two-color printing, the two-color grippers grasp the leading edge of the sheet from the second transfer cylinder. The third transfer cylinder then, through the twocolor grippers, transfers the leading edge of the sheet to the second impression cylinder without reversal.

When the third transfer cylinder is arranged to operate as a perfecting cylinder, the perfecting grippers, while abutting an outer stop member, engage the trailing edge of the sheet on the second transfer cylinder. The perfecting grippers rotate or tumble inwardly about their own axes into abutting relation with an inner stop member and the two-color grippers also tumble inwardly about their own axes into abutting relation with a similar inner stop member. The trailing edge of the sheet is transferred from the inwardly tumbled perfecting grippers to the mating two-color grippers to thus invert the sheet with the trailing edge from the second transfer cylinder becoming the leading edge. The original trailing edge is thus transferred from the two-color grippers to the second impression cylinder as the leading edge of the sheet so that the sheet is printed on the opposite side. With the mechanical gripper devices of the Gegenheimer patent abutting fixed mechanical stops in both the inner and outer position, the pickup, transfer and delivery of each sheet is exactly the same and desired registry is maintained.

The Gegenheimer et al. patent also discloses the use of suction devices on the periphery of the second transfer cylinder. The suction devices are peripherally spaced from the grippers on the transfer cylinder approximately the length of the sheet being handled. The suction devices are disposed behind the grippers with respect to the direction of rotation of the second transfer cylinder so that the trailing edge of the sheet is in overlying relation with the suction devices on the second transfer cylinder. After the grippers on the second transfer cylinder secure the leading edge of the sheet, the suction devices are actuated to cause the suction heads to engage the trailing edge of the sheet and thereby secure it to the cylinder periphery. When the second transfer cylinder has rotated to the point where the trailing edge of the sheet is on a line intersecting the centers of the second transfer cylinder and the third transfer cylinder, the suction is released and air is blown outwardly through the suction devices to facilitate separation of the sheet from the second transfer cylinder, and engagement by the perfecting grippers on the third transfer cylinder.

i The suction devices may be adjusted peripherally on the second transfer cylinder by moving them angularly about the central longitudinal axis of the second transfer cylinder. The adjustment of the suction device establishes a peripheral spacing with respect to the grippers on the second transfer cylinder that corresponds to the length ofthe sheet to be handled.

With the pairs of tumbling grippers such as those disclosed in Gegenheimer et al. US. Pat. No. 2,757,610, the grippers extend beyond the periphery of the cylinder on which they are mounted when the perfecting grippers engage the trailing edge of the sheet. The sheet handling mechanism disclosed in the (legenlteimer ct al. patent includes a second transfer cylinder with peripheral recessed portions. The extending grippers on the perfecting cylinder fit into these recessed portions to en gage the trailing edge ofthe sheet as above discussed.

To provide a perfecting typc press with impression cylinders on opposite sides of a single transfer cylinder that may also serve as a perfecting cylinder, it has been suggested that the perfecting cylinder include suction devices mounted on the periphery of the perfecting cylinder that tumble inwardly relative to the periphery of the perfecting cylinder. The rotatably mounted suction devices serve in effect, as perfecting grippers. The perfecting cylinder also includes rotatable grippers mounted behind (with respect to the direction of rotation of the cylinder) the suction devices. With this arrangement. it has been suggested in perfecting that the suction devices en gage the trailing edge of the sheet on an adjacent cylinder. The suction devices then tumble inwardly and transfer the trailing edge of the sheet to the inwardly tumbled grippers. The grippers, which are similar to the two-color grippers in Gegenheimer et al., then rotate outwardly to transform the trailing edge of the sheet into the leading edge of the sheet and transfer the sheet in its reversed position to an adjacent impression cylinder.

One ofthe major weaknesses with the above suggested solution is registry of the sheet for subsequent printing. The transfer of the edges of the sheet during perfecting requires great precision which is not possible with the above discussed rotatable suction devices on the perfecting cylinder. It has been found that the trailing edge of the sheet must be gripped firmly by the perfecting grippers during transfer to the twocolor grippers in order to maintain registry. There are substantial limitations in the use of suction devices for transferring sheets from one cylinder to another. These limitations are magnified when the suction devices are rotated or tumbled inwardly about their own axes before the sheet is transferred to the grippers.

The suction devices, for example, engage the trailing edge of the sheet while the leading edge of the sheet is engaged by grippers on the adjacent cylinder and tensions the sheet by tumbling inwardly before the leading edge of the sheet is released by the grippers on the adjacent cylinder. The suction devices continue to tumble inwardly to the inner position where the suction devices transfer the sheet to the gripper mechanisms. The movement of the suction devices is thus continuous from the time they engage the sheet until the time they are in position to transfer the sheet to the gripper devices. During this time interval, registry depends solely on the suction devices. Any flutter, vibration or motion of the sheet during this time interval will affect register.

Another major problem with the above suggested perfecting arrangement is the wrinkling of the sheet while on the first impression cylinder. In the suggested press, the sheet is engaged only by its leading edge on the impression cylinder and the trailing edge of the sheet is not positively engaged to the first impression cylinder. It is well known that the sheet tends to adhere to the blanket cylinder because ofthe adhesive properties of the ink. This factor alone would cause the trailing edge of the sheet to pull away from the first impression cylinder and cause the sheet to wrinkle. Another factor, Le. the centrifugal force of the rapidly rotating impression cylinder, would cause the trailing edge of the sheet to become disengaged so that wrinkling of the sheet would occur. The herein described invention eliminates the above discussed problems and now provides a perfecting press arrangement wherein the sheet is transferred directly from an impression cylinder to the perfecting cylinder, the edges reversed and then transferred directly to a second impression cylinder while registry is maintained and the sheet remains free of wrinkles.

SUMMARY OF THE INVENTION The hereinafter described invention includes a perfecting cylinder that has suction devices adapted to engage the trailing edge of the sheet at the tangent point with the adjacent first impression cylinder. The suction devices on the perfecting cylinder engage the trailing edge of the sheet while the leading edge of the sheet remains engaged by the grippers on the first impression cylinder. The suction devices then move along the periphery of the perfecting cylinder into abutting relation with a mechanical stopmember and tension the sheet to remove any wrinkles present in the sheet. The suction devices secure the trailing edge of the sheet to the perfecting cylinder and permit the perfecting cylinder to rotate to a position where the perfecting grippers are free to tumble outwardly beyond the periphery of the perfecting cylinder to a predetermined position controlled by a stop member and engage the trailing edge of the sheet. After the trailing edge of the sheet is engaged by the perfecting grippers, the suction devices release the trailing edge of the sheet. The perfecting cylinder continues to rotate and the perfecting grippers and two-color grippers tumble inwardly toward each other to a preselected position controlled by stop members while the trailing edge of the sheet is securely engaged by the perfecting grippers. The trailing edge of the sheet is then transferred to the two-color grippers and the grippers tumble outwardly to a preselected position where the trailing edge of the sheet, now the leading edge of the sheet is transferred to the grippers on the second impression cylinder. With this arrangement, a tension is first exerted on the sheet by the suction means to remove wrinkles therefrom and the suction means moves to a preselected position on the cylinder and abuts a mechanical stop means. In this position, the perfecting grippers abutting an outer stop member engage the sheet edge portion for transfer to the two-color grippers. The perfecting grippers firmly hold the sheet while the trailing edge of the sheet is transferred from one set of grippers to others. Because of the arrangement of the stop members for the suction means and the gripper devices, sheet flutter, vibration and the like does not result in loss of registry as would occur in the absence of positive stop members for the suction means and the grippers.

Accordingly, it is an object of this invention to provide a sheet fed perfecting press with a pair of impression cylinders adjacent to a perfecting cylinder and where a sheet is maintained in registry when it is transferred from the first impression cylinder to the second impression cylinder by the perfecting cylinder.

Another object of this invention is to provide a perfecting cylinder for use with adjacent impression cylinders that includes a means to remove wrinkles from the sheet on the first impression cylinder while registry is maintained.

It is a further object of this invention to provide a perfecting cylinder arranged to receive a sheet from an adjacent impression cylinder, reverse the edges of the sheet by suction devices and pairs of tumbler grippers and transfer the sheet in reversed position to a second impression cylinder while maintaining accurate registry during the transfer and sheet reversal.

It is an additional object of this invention to provide a sheet fed perfecting press with impression cylinders adjacent to the perfecting cylinder that is adapted to effectively handle sheets of various sizes.

These and other objects and advantages of this invention will be more completely disclosed and described in the following specification, the accompanying drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. I is a schematic representation of the perfecting cylinder with the suction devices, perfecting grippers and twocolor grippers. The drive means for the cylinder and the actuating means for the suction devices and grippers are illustrated diagrammatically.

FIG. 2 is a schematic illustration of a perfecting press with the perfecting cylinder positioned between the pair of impression cylinders. In FIG. 2, the suction device on the perfecting cylinder is illustrated at the tangent point between the first impression cylinder and the perfecting cylinder. The suction device in FIG. 2 has engaged the trailing edge ofa sheet.

FIG. 3 is a schematic illustration similar to FIG. 2 illustrating the perfecting cylinder rotated through approximately with the trailing edge of the sheet being transferred from the perfecting grippers to the two-color grippers.

FIG. 4 is a schematic illustration similar to FIGS. 2 and 3 illustrating the trailing edge of one sheet being transferred from the two-color grippers to the grippers on the second impression cylinder as the leading edge of the sheet and the trailing edge of another sheet engaged by the perfecting grippers as the perfecting grippers and two-color grippers tumble inwardly to each other for subsequent transfer of the trailing edge of the sheet from the perfecting gripper to the two-color grippers.

FIG. 5 is a fragmentary schematic view of a portion of the perfecting cylinder and first impression cylinder illustrating the perfecting grippers and the two-color grippers tumbled inwardly below the periphery of the perfecting cylinder and the suction device located on the periphery of the perfecting cylinder engaged to the trailing edge of the sheet on the impression cylinder.

FIG. 6 is a view similar to FIG. 5 illustrating the perfecting cylinder rotated to an extent where the perfecting grippers are free to tumble outwardly beyond the periphery of the perfecting cylinder and engage the trailing edge of the sheet secured by the suction devices.

FIG. 7 is a view similar to FIGS. 5 and 6 illustrating the trailing edge of the sheet engaged by the perfecting grippers.

FIGS. 8, 9 and I0 are similar to FIGS. 2, 3 and 4 and illustrate the perfecting cylinder transferring sheets that are less than full size.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings and particularly to FIGS. 2, 3 and 4, the perfecting press includes a perfecting cylinder generally designated by the numeral I0 with a first impression cylinder 12 positioned adjacent thereto and a second impression cylinder 14 positioned on the opposite side of the perfecting cylinder 10. A feed board 16 is positioned adjacent to a pick up cylinder I0 that feeds the sheets to the first impression cylinder 12. A conventional printing couple consisting of a plate cylinder and a blanket cylinder with suitable inkers and dampening units are associated with the first impression cylinder 12 and have been omitted from the drawings to more clearly illustrate the invention. A similar printing couple is associated with the second impression cylinder I4 and has not been shown for the same reason. It should be understood, however, that any conventional well known printing couple such as that illustrated in FIGS. I and 2 of Gegenheimer et al. could be used with the illustrated impression cylinders 12 and 14.

The impression cylinder 12 has a cylindrical surface 20 with a first longitudinal opening 22 and a diametrically opposed second longitudinal opening 24. The impression cylinder I2 may be of conventional well known construction and is suitably supported for rotation on shaft 26. A first set of grippers 27, only one of which is illustrated in FIGS. 2-10, is secured to a shaft within the cylinder 12 and have gripper fingers 28 arranged to engage the leading edge of the sheet and maintain the leading edge of the sheet in registry on the impression cylinder 12 while the upper surface of the sheet is printed. The first impression cylinder 12 has a second set of grippers 30 mounted on a shaft in recessed portion 24 with gripper fingers 32 arranged to engage the front edge of a second sheet and maintain the front edge of the sheet in registry while the sheet is being printed. The grippers 27 and 30 are of conventional construction and suitable sets of grippers and actuating means therefor are illustrated in the Gegenheimer et al. U.S. Pat. No. 2,757,610, FIGS. 8 and 9.

The second impression cylinder 14 is similar to the first impression cylinder 12 and includes a cylindrical surface with a.

first recessed portion or opening 36 and a diametrically opposed other recessed opening 38. Grippers 40 and 42 are rotatably secured within the impression cylinder 14 and have gripper fingers 44 and 46 that abut the peripheral surface of the cylinder 14 and are operable to engage the leading edge of a sheet to the periphery of the second impression cylinder 14. The second impression cylinder 14 is suitably mounted on a shaft 48 for rotation in timed relation with both the first impression cylinder l2'and the perfecting cylinder 10.

In FIGS. 2-4 and 8-l0, only one set of diametrically opposed grippers are illustrated on each impression cylinder. It should be understood, however, that a plurality of grippers extend longitudinally along the periphery of the cylinder surfaces 20 and 24 and the respective grippers on each cylinder are arranged to simultaneously engage the leading edge of the sheet and firmly secure the leading edge of the sheet to the surface of the impression cylinder while the sheet is being printed and either transferred to the perfecting cylinder or transferred to a suitable sheet delivery mechanism.

The perfecting cylinder is suitably mounted on a shaft 50 for timed rotation with the impression cylinders 12 and 14. The perfecting cylinder 10 is illustrated as having a cylindrical surface 52 with a first recessed portion 54 and a diametrically opposed recessed portion 56. It should be understood, however, that the perfecting cylinder 10 could be fabricated from a plurality of disclike members as is disclosed in Gegenheimer et al. U.S. Pat. No. 2,757,610. Positioned within the recess 54 are a plurality of suction devices 58 spaced longitudinally along the cylinder periphery 52. In FIG. 1, the suction devices 58 extend into slots 60 that extend radially from the recessed portion 54. It should be noted, however, that the slots 60 provide for movement of the suction devices along the periphery 52 of perfecting cylinder 10. Similar suction devices 62 extend outwardly from the cylinder 10 and terminate along the peripheral surface 52. The suction devices 58 and 62 are similar in construction and only the suction devices 58 will be described in detail since the suction devices 62 operate in substantially the same manner. The suction devices 58 have an arm portion 64 nonrotatably secured'to a shaft 66 extending longitudinally within the perfecting cylinder 10. The arm portions 64 terminate in a head portion 68 that has a foraminous or perforated outer end portion that terminates at the periphery of the perfecting cylinder cylindrical surface 52. The suction devices are arranged to move along the periphery of the perfecting cylinder 10 to a limited extend by rotation of shaft 66. The arm portion 64 of suction devices 58 are arranged upon rotation of shaft 66 in a counterclockwise direction, as illustrated in FIGS. 5-7 to abut a stop member 67 to thereby limit the rotational movement and position the sheet edge portion for engagement'by the'perfecting gripper assembly as later described.

An arrangement whereby the suction heads are permitted to move along the periphery of the suction heads and the manner for controlling the movement of the suction heads is illustrated and described in copending application Ser. No. 602,857 entitled Sheet Tensioning and Transfer Mechanism For Presses". The arrangement disclosed in the above application could, with equal facility, by used on perfecting cylinder 10 to move the suction devices 58 and 62'for the purpose later described.

The tumbler gripper assemblies are generally designated by the numeral 70 in FIG. 1 and include a perfecting gripper assembly generally designated by the numeral 72 and a two,-

color gripper assembly generally designated by the numeral 74. The perfecting gripper assembly 72 and two-color gripper assembly 74 are arranged to tumble inwardly toward each other and abut stop members 73 and 77 and in this position remain within the periphery of the perfecting cylinder 10. The

perfecting gripper assembly 72 and two-color gripper assembly 74 are also arranged to tumble outwardly away from each other and beyond the periphery of the perfecting cylinder 10 and abut stop members 75 and 79 so that the perfecting grippers can engage the trailing edge of the sheet secured by the suction devices 58 on the perfecting cylinder 10 and the two-color grippers can transfer the sheet to the second impression cylinder. The perfecting gripper assembly 72 and two-color assembly 74 may be similar in construction to the perfecting gripper assembly and two-color gripper assembly illustrated in Gegenheimer et al. U.S. Pat. No. 2,757,610. Also, similar apparatus to that illustrated in the Gegenheimer et al. patent for tumbling the gripper assemblies inwardly toward each other and outwardly away from each othermay be employed to tumble the perfecting gripper assembly 72 and two-color gripper assembly 74 in the perfecting cylinder disclosed in the instant application. Other suitable means to tumble or rotate the perfecting gripper assembly 72 and two-color gripper assembly 74 may also be used as long as the grippers perform the purposes hereinafter discussed.

The perfecting cylinder 10 has a second pair of tumbler gripper assemblies generally designated by the numeral 76 within the recess 56 and diametrically opposed to the tumbler gripper assemblies 70. The tumbler gripper assemblies 76 include a perfecting gripper assembly generally designated 78 and two-color gripper assembly 80. The perfecting gripper as-- sembly 78 and two-color gripper assembly 80 are similar to the perfecting gripper assembly 72 and two-color gripper assembly 74 and will not be described in detail. The same type of mechanism as is illustrated in Gegenheimer et al. may be used to tumble the respective perfecting and two- color gripper assemblies 78 and 80 in a manner similar to the perfecting and two- color gripper assemblies 72 and 74 as hereinafter described.

The tumbler gripper assemblies 70 and 76 are diagrammatically illustrated in the drawings. FIGS. 5, 6 and 7 illustrate the essential elements of the tumbler gripper assembly 70. A perfecting gripper tumbler shaft 82 extends longitudinally within the perfecting cylinder 10 and is journaled for rotation therein. Nonrotatably connected to shaft 82 is an arm 84 that rotatably supports a gripper finger shaft 86. The shaft 82 has a hub portion nonrotatably secured thereto with radially extending flange portions 81 and 83. The flange portion 81 (FIG. 5) is operable to abut stop member 73 and limit inward movement of the gripper assembly 72. Similarly, the flange portion 83 (FIGS. 6 and 7)-is operable to abut stop member 75 and limit outward movement of the gripper assembly 72. Thus, rotation of shaft 82 in a clockwise direction, as viewed in FIGS. 5, 6 and 7, causes the arm 84 to rotate therewith and move the gripper finger shaft toward the perfecting cylinder periphery to a predetermined location controlled by flange 83. Similarly, rotation of shaft 8 2 in a counterclockwise direction causes the arm 84 to rotate therewith and move the gripper finger shaft inwardly away from the cylinder periphery to a predetermined location controlled by flange 81. Extending radially from the arm 84 is a gripper pad bracket 88 that has a gripper surface 90 thereon.

Secured to the shaft 86 and rotatable therewith are gripper fingers 92 with a toe portion 94 that is arranged upon clockwise rotation of shaft 82 to engage the gripper pad. surface 90 and secure a sheet therebetween. Suitable actuating I means are provided to rotate shaft 82 to tumble both the gripper pad bracket 88 and gripper fingers 92 inwardly toward the center of the perfecting cylinder 10 so that stop member 73 is in abutting relation with flange 81 or outwardly toward the periphery of the perfecting cylinder 10 so that stop member 75 is in abutting relation with flange 83. Other actuating means are provided to rotate the gripper finger shaft 86 and move the gripper finger toe portion 94 into or out of engagement with the gripper surface 90.

The two-color gripper assembly 74 is similar in construction and has a two-color tumbler shaft 96 extending longitudinally therethrough in space relation to the perfecting gripper tum bler shaft 82. Nonrotatably secured to shaft 96 is an arm member 98 that extends radially therefrom. The shaft 96 has a hub portion nonrotatably secured thereto with radially extending flange portions 95 and 97 (FIGS. 6 and 7). The flange portion 95 is operable to abut stop member 77 and limit inward movement of the gripper assembly 74. Flange portion 97 is operable to abut stop member 79 and limit outward movement of the gripper assembly 74.

A gripper finger shaft 100 is rotatably secured within the arm member 98 and has gripper fingers 102 nonrotatably secured theretov A gripper pad bracket 104 extends radially from the arm 98 and has a gripper surface 106 thereon and the gripper finger 102 has a toe portion 108 that is arranged to abut surface 106 and engage the edge of a paper sheet therebetween. Thus, by rotation of tumbler shaft 96 the twocolor gripper assembly 74 is moved inwardly toward the center of the perfecting cylinder to a location where flange 95 abuts stop member 77. Suitable separate means may be provided to rotate two-color tumbler shaft 96 to move the gripper assembly. The gripper finger shaft 102 is rotatable relative to the two-color tumbler shaft 96 to move the gripper finger toe portion 108 into and out of engagement with the gripper surface 106. Again, suitable means are provided to separately rotate gripper finger shaft 100 to perform the functions hereinafter described.

In FIG. 1, the perfecting cylinder 10 has indicated diagrammatically and connected thereto by dotted lines, suitable means to rotate the perfecting cylinder 10, to actuate the suction devices 58, to actuate the suction device shaft, to actuate the perfecting gripper tumbler shaft. to actuate the two-color tumbler shaft, to actuate the perfecting gripper finger shaft and to actuate the two-color gripper finger shaft. It should be understood, the various actuators may be cam means or the like wherein the relative position of the shafts within the perfecting cylinder is determined by the relative position of the perfecting cylinder to the adjacent impression cylinder.

OPERATION Referring firstto FIGS. 2, 3 and 4 there is illustrated a first sheet 51 that has its leading edge engaged by the grippers 32 on the impression cylinder 12. The sheet S1 has passed through the printing couple and has been printed on its outer surface. Note in FIG. 2 where the sheet S1 has a wrinkle W1 .formed therein. In FIG. 2, the trailing edge of the sheet is being engaged by the suction device 58 at the tangent point between the first impression cylinder 12 and the perfecting cylinder 10. The manner in which the wrinkle W1 is removed from sheet 51 is illustrated in FIG. 5. The suction head 68 is normally in the position shown in dotted lines in FIG. 5. As the trailing edge of the sheet S1 is engaged by the suction device 58, the suction device shaft 66 rotates in a counterclockwise direction to exert a tension on the sheet 81 on the impression cylinder periphery 20. The front edge of sheet S1 is engaged by the grippers 32 and the movement of suction device 58, as illustrated in FIG. 5, exerts a tension on the sheet 81 sufficient to remove the wrinkle W1 and the suction device 58 moves against the stop 67 (FIG. 5) where the sheet edge portion remains in fixed position on the perfecting cylinder 10. After the wrinkle W1 is removed, the gripper device 32 on impression cylinder 12 releases the leading edge of the sheet S1 and the sheet is engaged by the suction device 58 to transfer the sheet by the trailing edge from the impression cylinder 12 to the perfecting cylinder 10. It should be noted that the suction head 68 is coextensive with the periphery of the perfecting cylinder so that there is no interference between the impression cylinder 12 and perfecting cylinder 10 as the suction device 58 rotates past the tangent point between the cylinders l2 and 10 and when the suction device 58 rotates to a predetermined position on the perfecting cylinder 10 controlled by the stop member 67. The suction device 58 remains fixed and a tension is exerted on the sheet before it is transferred from the impression cylinder 12 to the perfecting cylinder 10.

As is illustrated in FIG. 5, when the suction device 58 is at the tangent point between cylinders 12 and 10, the perfecting gripper assembly 72 and two-color gripper assembly 74 are tumbled inwardly toward each other and against the respective stops 73 and 77 so that they are within the periphery of the perfecting cylinder 10. The perfecting gripper assembly 72 and two-color gripper assembly 74 remain within the periphery of perfecting cylinder 10 as they pass the tangent point between the impression cylinder 12 and the perfecting cylinder 10. The trailing edge of the sheet, however, has been engaged by the suction device 58, tensioned and transferred from the impression cylinder 12 to the perfecting cylinder 10 by the suction device 58.

After the perfecting cylinder 10 has rotated to an extent that the perfecting cylinder gripper assembly 72 and two-color gripper assembly 74 are beyond the tangent point between impression cylinder 12 and perfecting cylinder 10, the perfecting gripper tumbler shaft 82 is rotated in a clockwise direction as illustrated in FIG. 6 to tumble the perfecting gripper assembly 72 outwardly against the stop 75 so that the trailing edge of the sheet S1 is in overlying relation with the gripper pad while the sheet is still engaged by the suction device 58.

After the perfecting cylinder rotates further, the gripper finger shaft 86 rotates to engage the sheet edge portion between the gripper pad surface 90 and the gripper finger toe portion 94, FIG. 7. After the trailing edge of the sheet 51 is engaged by the perfecting gripper assembly 72, the suction device 58 is deenergized to release the sheet and the trailing edge of the sheet is engaged to the perfecting cylinder 10 by the perfecting grippers 72. Upon further rotation of the perfecting cylinder 10, the perfecting gripper assembly 72 engaging the trailing edge of the sheet S1 is tumbled inwardly by the counterclockwise rotation of perfecting gripper tumbler shaft 82 against the stop 73 as is illustrated in FIG. 3. The two-color gripper pad 106 is in overlying relation with the perfecting gripper pad 90 and the two-color gripper fingers 102 are moved into overlying relation with the gripper pad 106 and engage the trailing edge of the sheet. The perfecting gripper fingers 92 move away from the gripper pads 90 to release the trailing edge of the sheet. The trailing edge of the sheet S1 now engaged by the two-color gripper assembly 74 becomes the leading edge of the sheet.

The two-color gripper tumbler shaft 96 rotates in a counterclockwise direction to move the leading edge of the sheet (previously the trailing edge of the sheet) to the periphery of the perfecting cylinder 10. At the tangent point between the second impression cylinder 14 and the perfecting cylinder 10, the reversed sheet is engaged by the grippers 46 on the second impression cylinder 14 and transferred thereto from the perfecting cylinder 10.

Thus, with the suction devices, the tumbler grippers on the perfecting cylinder 10 and the associated stop members, it is now possible to engage the trailing edge of the sheet from an adjacent impression cylinder by suction devices and to reverse the sheet while transferring it to a second adjacent impression cylinder and maintain accurate registry. The versatility of the above previously described apparatus is illustrated in FIGS. 8, 9 and 10 where the sheets of less than full size are handled by the perfecting cylinder with the same accuracy as a full sized sheet. With sheets of less than full size, the problem of interference between the first impression cylinder and adjacent perfecting cylinder 10 is exemplified. It is essential because the impression cylinder has a continuous cylindrical surface beneath the trailing edge of the sheet that the transfer means, [.e. the suction devices and the tumbler gripper assemblies, not extend beyond the periphery'of the perfecting cylinder at the tangent point with the first impression cylinder.

FIGS. 8-10 illustrate a sheet S2 of about one half the length of the sheet S1 illustrated in FIGS. 24 inclusive. A wrinkle W2 is also illustrated in sheet S2. The trailing edge of the sheet S2 is engaged by the suction device 58 and while the leading edge of sheet S2 is engaged by gripper 32 on impression cylinder 12, the suction device 58 moves in a counterclockwise direction as illustrated in FlGS. 8-10 to exert a tension on sheet S2 and remove the wrinkle W2. After the perfecting grippers 72 and two-color grippers 74 havepassed beyond the tangent point between perfecting cylinder and impression cylinder 12, the perfecting grippers 72 rotate outwardly to position the perfecting gripper pad 90-beneath the trailing edge of the sheet S2. The sheet is then engaged by the gripper fingers 92 of perfecting gripper assembly 72 and the perfecting gripper assembly. 72 is tumbled inwardly as illustrated in H0. 9 where the trailing edge of the sheet is transferred from the perfecting gripper assembly 72 to the twocolor gripper assembly 74 and is thereafter transferred from the perfecting cylinder 10 to the second impression cylinder 14 in the same manner as previously described.

Although dependent rotation of the perfecting gripper assembly 72 and two-color gripper assembly 74 is illustrated and described, it should be understood that the inward and outward tumbling of the perfecting and two- color gripper assemblies 72 and 74 may be practiced as is illustrated and described in the Gegcnheimer et'al. patent. With the latter arrangement. however, it is essential that both the perfecting gripper assembly 72 and the two-color gripper assembly 74 pass beyond the tangent point-of the adjacent cylinders 10 and 12 before the gripper assemblies 72 and 74 begin'to tumble outwardly so that there will'be no interference between the two-color gripper assembly 74 and the surface of the first impression cylinder 12.

The suction exerted by the suction head 68 on the sheet should be sufficient to engage the sheet and hold the sheet as it is transferred to the perfecting gripper assembly 72. Where, however, the sheet is not wrinkled as hasbeen illustrated and described, provisions are made to permit relative sliding movement between the sheet trailing edge and the suction head. A stop member 67 associated with the suction device 58 so that the trailing edge of the sheet is always in proper registry. The suction device 58 may be of conventional construction having a foraminous type suction head that engages the sheet when the vacuum has a suction head that exerted thereon. The arm 64 is adapted for limitedrotational movement about the axis of shaft 66 to move the suction head along the periphery of perfecting cylinder 10. The extent of rotation of the suction device is relatively small to exert the desired tension on the sheet before transfer to the perfecting cylinder for proper registry.

It will be appreciated that while for purposes of illustration, specific gripper assemblies have been shown, other suitable gripper assemblies will be apparent to those skilled in the art. The gripper assemblies must be adapted to be retracted within the periphery of the perfecting cylinder when. passing the tangent point between the perfecting cylinder and the first impression cylinder.

According to the provision of the patent statutes, we have explained the principle, preferred construction and mode of operation of our invention and have illustrated and described what we now consider to represent its best embodiments. However, we desire to have it understood that, within thescope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

1. A method of printing comprising:

printing upon a surface of a sheet on a first impression cylinder; I

engaging the trailing edge of said sheet while on said first impression cylinder by a suction means on an adjacent transfer cylinder with the printed surface of said sheet facing outwardly on said adjacent transfer cylinder;

engaging the trailing edge of said sheet by first gripper means on said transfer cylinder while said sheet trailing edge is engaged by said suction means on said transfer cylinder;

transferring the trailing edgeof said sheet from said first gripper means to second gripper means on said transfer cylinder; and thereafter transferring the trailing edge of said sheet as the leading edge of said sheet to an adjacent second impression cylinder from said second gripper means and printing upon the opposite surface of said sheet on said second impression cylinder. I

2. A method of printing as set forth in claim 1 which includes, moving said suction means in a direction opposite to the direction of rotation of said transfer cylinder to thereby exert a tension on said sheet by said suction means while said sheet is on said first impression cylinder,

3. A method of printing as set forth in claim 1 which includes, engaging the trailing edge of said sheet by said suction means at a location adjacent the point of tangency between said adjacent first impression cylinder and said transfer cylinder and moving said suction means in a direction opposite to the direction of rotation of said transfer cylinder into abutting relation with a stop means.

4. A method of printing as set forth in claim 3 which includes, engaging the trailing edge of said sheet by said first gripper means at a location other than the point of tangency between said adjacent first impression cylinder and said transfer cylinder.

5. A method of printing as setforth in claim 1 which includes:

engaging the leading edge of said sheet by third gripper means on said first impression cylinder;

engaging said sheet trailing edge by said suction means on said adjacent transfer cylinder while said sheet leading edge is engaged by said third gripper means on said first impression cylinder; and

moving said suction means along the periphery of said transfer cylinder in a direction opposite the direction of rotation of said transfer cylinder after said sheet trailing edge is engaged by said suction means and said sheet leading edge is engaged by said third gripper means on said first impression cylinder to thereby exert a tension on said sheet while on said first impression cylinder.

6. A sheet fed offset printing press assembly comprising:

a perfecting cylinder positioned between a first and second impression cylinder to sequentially receive and transfer the trailing edge of a sheet from said first impression cylinder as the leading edge of said sheet to said second impression cylinder, said perfecting cylinder having a saction device along the periphery thereof;

actuator means to actuate said suction device so that the sheet is engaged by said suction device while the sheet is secured on said first adjacent impression cylinder andthe sheet is engaged by said suction device after release thereof by said adjacent impression cylinder, said actuator means arranged to actuate said suction device and engage the sheet at a location adjacent the trailing edge of the sheet;

said perfecting cylinder having first gripper means pivotally mounted within said perfecting cylinder and disposed closely adjacent to said suctionmeans, said first gripper means positioned to receive and engage the trailing edge of the sheet prior to release of the sheet by said suction device on said perfecting cylinder and to secure the sheet to said perfecting cylinder after release of the sheet by said suction device;

said perfecting cylinder having second gripper means pivotally mounted within said perfecting cylinderand disposed closely adjacent to said first gripper means, said second gripper means positioned to receive the trailing edge of the sheet from the first gripper means and engage the trailing edge of the sheet prior to release of said trailing edge of said sheet by said first gripper means and to secure said sheet to said perfecting cylinder after release of the sheet by said first gripper means; and

said second gripper means arranged to transfer the sheet to a second adjacent impression cylinder as the leading edge of the sheet so that the trailing edge of the sheet is transformed into the leading edge of the sheet on the second impression cylinder.

7. A sheet fed offset printing press assembly as set forth in claim 6 which includes propelling means to move said suction means along the periphery of said perfecting cylinder and exert a tension on the sheet while the sheet is engaged on the first impression cylinder.

8. A sheet fed offset printing press'assembly as set forth in claim 7 in which said propelling means is timed to move said suction means along the periphery of said perfecting cylinder when said suction means is at a location adjacent the point of tangency between said first impression cylinder and said perfecting cylinder.

9. A sheet fed offset printing press assembly as set forth in claim 6 which includes means to pivot said first and second gripper means in timed relation to each other and tumble said first and second gripper means inwardly toward each other within the periphery of the perfecting cylinder when said first and second gripper means pass through the point of tangency between said first impression cylinder and said perfecting cylinder.

10. A sheet fed offset printing press assembly as set forth in claim 6 in which said means to pivot said first gripper means is arranged to tumble said first gripper means outwardly beyond the periphery of said perfecting cylinder when said first gripper means is at a location other than the point of tangency between the perfecting cylinder and first impression cylinder to engage and transfer the trailing edge of the sheet from the suction means.

i 11. A sheet fed offset printing press assembly as set forth in claim 10 in which said means to pivot said first gripper means is arranged to tumble said first gripper means inwardly and transfer the trailing edge of the sheet from said first gripper means to said second gripper means.

12. A sheet fed offset printing press assembly as set forth in claim 11 in which said means to pivot said second gripper means is arranged to tumble said second gripper means outwardly beyond the periphery of the perfecting cylinder to transfer the trailing edge of the sheet as the leading edge of the sheet to the second impression cylinder.

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