US3389657A - Apparatus for transferring sheets in register within a printing press - Google Patents

Description

' June 25,1968 T. SCHWABACH 3,389,657

APPARATUS FOR TRANSFERRING SHEETS REGISTER WITHIN A PRINTING PRES Filed June 2, 1966 2 Sheets-Sheet 1 June 25, 1968 'r SCHWABACH 3,389,657

APPARATUS FOR TRANSFERRING SHEETS IN REGISTER WITHIN A PRINTING PRESS Filed June 2, 1966 2 Sheets-Sheet 2 United States Patent 3,389,657 APPARATUS FOR TRANSFERRING SHEETS IN REGISTER WITHIN A PRINTING PRESS Teo Schwabach, Wurzburg, Germany, assignor to Schnellpressenfabrik Koenig & Bauer Aktiengesellschaft, Wurzburg, Germany Filed June 2, 1966, Ser. No. 554,738 6 Claims. (Cl. 101-232) ABSTRACT OF THE DISCLOSURE The invention consists of a gripper unit for sheets mounted on a link chain conveyor, which unit can be rigidly latched to the chain sprocket drive shaft during sheet transfer. This is done by holding a roller attached to the gripper unit in a three point contact by V-shaped supports attached to arms mounted on the drive shaft and by a moveable hook. The gripper unit also has set screws on either side of the roller to engage the arms and prevent rocking.

The present invention relates to an apparatus for transferring sheets in exact register from one printing cylinder of a printing press to another by means of a gripper chain so that especially for the purpose of multi-color printing the same points on each sheet will be located precisely in the same positions on the different printing cylinders.

It is the principal object of the invention to provide a gripper chain comprising a pair of parallel endless link chains and gripper elements thereon, and associated apparatus which cooperate with the gripper elements of this chain for insuring that the sheet transfer from one printing cylinder to the gripper chain and from the latter to another printing cylinder will always occur in a register as precise as it has previously not been possible to attain by similar apparatus which were developed prior to this invention.

For attaining this object, the invention provides that the sheet transfer occurs entirely independently of the inaccuracies of the construction and movement of the two link chains and that for this purpose during the time of each sheet transfer from the printing cylinder to the gripper chain the supporting means of the gripper elements which are mounted on the chains are positively locked by suitable means in the most suitable position to the solid drive shafts of the sprocket wheels for the chains so that the particular position of the gripper elements depends during this time upon the accurate rotation of these shafts and is not affected by the inaccurate movements of the chains. Consequently, the accurate position of the gripper elements at the time of each sheet transfer will also not be affected by the centrifugal forces which act upon the chains and the gripper systems thereon especially when these chains are driven at a very high speed. Since the supporting means of the gripper elements are securely locked in a fixed position to the shafts of the sprocket chains at the moment of each sheet transfer, there is also no longer any need to make these supporting means of an extremely solid and heavy construction as it was necessary in previous apparatus of this type in order to prevent these supporting means from being bent or displaced in the operation of the printing press.

According to the invention, the gripper elements comprise several parallel rows or systems of tonglike grippers each of which consists of an arm which is pivotable relative to a fixed abutment. The gripper arms of each system are secured to a common shaft which is cam-controlled so as to be rotated back and forth to pivot all of the gripper arms in unison relative to their opposite abutment and to grip the end of a sheet on a printing cylinder substantially at the same time when this end is released from the printing cylinder by similar grippers or other suitable means. The opposite ends of this gripper shaft are rotatably mounted in bearing means which according to the invention are preferably of a resilient construction .and secured to one side of each of the two chains. These bearing means for each gripper system may consist, for example, of a pair of parallel bearing plates in which the opposite ends of the mentioned gripper shaft are rotatably mounted and which are rigidly connected to each other at least by a bar or rod on which the gripper abutments are mounted. These bearing plates may either consist of a resilient material or, more preferably, each of them may be provided with a pair of bushings of soft rubber or similar material into which the extended ends of two of the link pins of one of the link chains are inserted.

The above-mentioned locking means for locking each gripper system during the short period of the sheet transfer to the drive shaft of the two chains essentially consist according to the invention of at least one crossbar which rigidly connects the bearing plates to each other and carries the gripper abutments, of several supporting elements which are mounted on this crossbar at suitable distances from each other and also serves as additional intermediate bearing means for the gripper shaft, of a supporting and locking roller which is rotatably mounted on each of the supporting elements, of a plurality of prismatic bearings which are adapted to receive the locking rollers when the gripper system is located in its sheet transfer position and are rigidly secured to the drive shaft by being mounted on arms which are secured to and project laterally from the drive shaft, of a pair of setscrews which are adjustably mounted on each supporting element at both sides of the locking roller and engage upon the end surface of the associated arm on the drive shaft and maintain the supporting element and the gripper system in the proper angular position in the peripheral direction of the drive shaft, and of a cam-controlled locking member which is adapted to lock the supporting element and the gripper system thereon in a fixed position to the prismatic bearing and thereby to the drive shaft during the period of the sheet transfer. This locking member may, for example be hook-shaped and pivotable about an axis which in the sheet transfer position intersects a plane which extends through the axes of the sprocket-wheel drive shaft and the locking roller and also substantially through the axis of the printing cylinder. In order to exert the necessary pressure upon the locking roller so as to press the same firmly upon the prismatic bearing and thus to attain a secure three-point support for the locking roller, this locking member may either possess a small amount of resilience or exert a slight wedging action upon the locking roller. The mentioned setscrews generally need to be adjusted only once during the normal life of the chains and the entire gripper systems, and they insure that these systems will remain in their proper adjustment during this entire length of time. Thus, when it becomes necessary to readjust the length and tension of the chains, there will be no need also to readjust the gripper systems in order to insure that the sheet will be transferred in exact register from one printing cylinder to another.

The locking mechanism as previously described therefore maintains the gripper system at every sheet transfer in an absolutely fixed position without play in any direction and it insures an exact register even for the most difficult forms, fine screens and multicolor prints. The gripper systems which are carried by the two chains and may be of any desired number may be very accurately adjusted at the place of manufacture of the printing press and they do not need to be again adjusted during the life time of the chains since any changes in length of the chains or any wear upon the individual elements of the gripper systems will not affect the proper adjustment and positioning of these systems during the sheet transfer. The gripper systems will even be in exact regis tcr if the rotation of the printing press is reversed. The present invention is primarily concerned with attaining an exact registry in the sheet transfer in the direction of travel of the chains and sheets since it does not involve any particular difficulties to adjust the gripper systems also in lateral directions shortly before they are locked in the manner as described.

The features and advantages of the present invention will become further apparent from the following detailed description of one preferred embodiment thereof which is to be read with reference to the accompanying, partly diagrammatic drawings, in which FIGURE 1 shows, partly in section, a side view of one of the gripper systems in the sheet transfer position, while FIGURE 2 shows, partly in section and partly broken away, a top view of the gripper system according to FEGURE 1.

In these drawings, FIGURE 1 shows one of the gripper systems according to the invention in the sheet transfer position adjacent to the printing cylinder 1 of a printing press which is merely indicated by an arcuate line. A pair of sprocket wheels 2, as indicated in FIGURE 1 by a dot-and-dash line, are rigidly secured to a drive shaft 4 and carry a pair of endless link chains 3. Both of these chains 3 carry on their inner sides facing each other a series of bearing plates in corresponding positions. They are spaced from each other at a distance equal to the circumference of the printing cylinder. These bearing plates 9 are resiliently mounted on the two chains 3 and are for this purpose provided with bores in which bushings 21 of soft rubber or a similar material are secured which are mounted on extensions it) of some of the link pins of each chain 3. Bearing plates 9 are provided with bores or bearings for rotatably mounting the outer ends of a shaft 5, and they are rigidly secured to each other by a rod 6 and preferably in addition by an angle iron 27. As illustrated in FIGURE 2, shafts 5 and rod 6 carry at their center and at equal distances from their ends three supporting plates 12, each of which is provided with a bore in which the shaft 14 of a ground locking roller 15 is mounted which is freely rotatable as long as it is not in its locked position, as subsequently described. Shaft 5 carries a row of grippers '1" and is adapted to be rotated back and forth by being provided with an arm, not shown, which is acted upon by a cam plate, likewise not shown, so as to pivot these grippers back and forth relative to fixed abutments 8 on rod 6. Between the circular ends of the printing cylinder, as indicated by the arcuate line 1 in FEGURE 1, this cylinder is provided with a longitudinal recess, not shown, into which the row of grippers 7 engages when during the continuous movements of the printing cylinder and the chains 3 the opened grippers approach the sheet transfer position, as shown in F1 URE 1, in which the end of the sheet is released from the printing cylinder by similar grippers or other suitable holding rneans and is gripped substantially at the same time between the ends of the grippers 7 and the abutments 8.

When the row of grippers 7 arrives in the sheet transfer position, the axes of drive shaft 4, shafts 14 of rollers 15, and rod 6 which carries the abutments t are located substantially within the same plane which then also substantially intersects the axis of the printing cylinder 1. Drive shaft 4 also also rigidly secured thereto three supporting arms 17 in alignment with the three supporting plates 12 (and therefore not visible in the top view according to FIGURE 2). Each of these arms l7 carries rigidly on one side thereof a prismatic bearing 16 which. is located Within the plane of travel of the associated locking roller 15. When the gripper system approaches the sheet transfer position, as shown in FIGURE 1, the three locking rollers 15 slide from above like ground teeth into the prismatic bearings 16 and rest on the opposite surfaces thereof which thereby support the entire gripper system. When the locking rollers 15 are in this position, their ends laterally project beyond the prismatic bearings 16 and will then be immediately pressed into locking engagement with the bearing surfaces by hooks 18 which are secured to a. shaft 19 which is rotatably mounted in the supporting arms 17 and the axis of which is likewise disposed within the common plane within which the axes of shafts 4 and 14 and of rod 6 are located when the gripper system is in its sheet transfer position. Shaft 19 is provided with a laterally projecting arm, not shown, which is acted upon by a cam plate, likewise not shown, so as to pivot the hooks 18 from their open position as shown in FIGURE 1 in dotand-dash lines to their locking or sheet-transfer position as shown in dotted lines. in order to exert the necessary locking pressure upon the rollers 15, hooks 13 may be either slightly resilient or they may exert a slight wedging action upon the rollers 15 when they are pivoted to their locking position. During the sheet transfer, not only the two outer locking rollers 15 are thus rigidly clamped to the drive shaft 4, but also the central locking roller 15 so that there is no danger that the gripper system might be affected by the centrifugal forces acting thereon and that due to these forces the sheets might not be transferred in exact register from one printing cylinder to the other. Since the entire gripper system is thus securely locked to the solid drive shaft 4 on which the sprocket wheels for driving the chains 3 are mounted, this entire system including the gripper shaft 5 and the supporting rod 6 may be made of a very light construction.

In order to adjust and maintain the bearing plates 9 and thus the entire gripper system also in the proper fixed position in the peripheral direction of the drive shaft 4 and the sprocket wheels 2 thereon so that the grippers 7 and their associated abutments 8 will always be in the proper gripping position at the moment of the sheet transfer, the bottom side of each supporting plate 12 is provided at the opposite sides of the locking roller 15 with a pair of setscrews 23 and 24 which during the period of the sheet transfer solidly en age upon the end surfaces of a pair of projections 25 and 26 on one of the supporting arms 17 which are secured to the drive shaft 4.

The purpose of mounting the bearing plates 9 on the links pins 10 of the chains 3 by means of the rubber bushings 21 is primarily to compensate for the changes in the angular position of these links pins relative to each other and to the bearing plates, if they consist of a rigid material, and further to compensate for unavoidable play due to inaccuracies of manufacture of the gripper system and to reduce the noise of operation of the gripper system.

The necessary cam plates for controlling the movements of the gripper shaft 5 and the hooks 18, as well as the arms on shafts 5 and 19 which are acted upon by these cam plates so as to pivot these shafts about their axes are not illustrated in the drawings since they would render these drawings too complex and also since they are obvious to any person who is skilled in the art .of the transmission of movements.

Although my invention has been illustrated and described with reference to the preferred embodiment thereof, I wish to have it understood that it is in no way limited to the details of such embodiment but is capable of numerous modifications within the scope of the appended claims. Having thus fully disclosed my invention, what I claim is:

1. In combination with a printing press having a plurality of printing cylinders, an apparatus for transferring sheets in exact register from one of said cylinders to another comprising a plurality of drive shafts, a pair of sprocket wheels secured to each drive shaft, a pair of endless link chains .on said sprocket wheels, a plurality of bearing elements forming pairs mounted in corresponding positions on said chains at the sides thereof facing each other, at least one crossbar rigidly connecting each pair of bearing elements to each other, a gripper shaft rotatably mounted at its opposite ends on said pair of bearing elements, a plurality of grippers secured to said gripper shaft, fixed abutments mounted on said crossbar and associated with said grippers for receiving and gripping the end of a sheet coming from an adjacent printing cylinder during the rotation thereof, means for turning said gripper shaft back and forth for pivoting said grippers relative to said abutments, a plurality of supporting elements secured to said crossbar and laterally spaced from each other between said bearing elements, said gripper shaft extending through and being rotatably mounted by said supporting elements, a roller rotatably mounted on each of said supporting elements and centrally on one side thereof opposite to the side on which said abutments are located and extending parallel to said supporting bar and to said gripper shaft, a plurality of supporting arms equal to the number of said supporting elements rigidly secured to said drive shaft, a prismatic bearing secured to each of said supporting arms and having two bearing surfaces disposed at an angle to each other and adapted to receive said roller mounted on the associated supporting element when said grippers on said supporting elements are substantially in their sheet transfer position, bracing means on each of said supporting elements at both sides of said roller adapted in said sheet transfer position to engage upon the end of said supporting arm when said roller engages with and rests at two sides upon said bearing surfaces of said prismatic bearing, a locking element adapted to be moved into engagement with a third side of said roller and to press said roller in said sheet transfer position upon said two bearing surfaces of said prismatic bearing, and means for moving said locking element into and out of engagement with said roller.

2. An apparatus as defined in claim 1, in which each of said locking elements consists of a hook-shaped members, said means for moving said locking element comprising a locking shaft rotatably mounted in all of said supporting arms, said hook-shaped members being secured to said locking shaft, said locking shaft having an axis disposed substantially within a common plane extending through the axes of said drive shaft, said rollers, and said printing cylinder, and through the center of said abutment when said grippers are substantially in their sheet transfer position, and means for rotating said locking shaft back and forth for pivoting said hook-shaped members into and out of engagement with said rollers.

3. An apparatus as defined in claim 1, in which said bracing means comprise a pair of setscrews for adjusting the angular position of each of said supporting elements relative to said drive shaft in the peripheral direction thereof.

4. An apparatus as defined in claim 1, in which each of said bearing elements which is connected to one of said chains is at least partly resilient so as to adapt itself to the angular displacements of the links of said chain relative to each other.

5. An apparatus as defined in claim 1, in which each of said chains comprises link pins projecting from one side of said chain, each of said bearing elements comprising a plate containing soft-rubber sockets mounted on at least two of said link pins.

6. An apparatus as defined in claim 1, in which said supporting elements on said crossbar, the associated supporting arms on said drive shaft and said prismatic bearings thereon, and the associated locking elements are mounted at substantially equal distances from each other along the length of said shafts so as to support and lock said gripper shaft at a plurality of points along its length on said drive shaft.

References Cited UNITED STATES PATENTS 1,093,152 4/1914 Smith et a1. 198-180 X 2,815,208 12/1957 Wood 271- 2,821,390 1/1958 Norton 27145 3,167,006 1/1965 Peyrebrune 101-183 ROBERT E. PULFREY, Primary Examiner.

E. H. EICKHOLT, Assistant Examiner.

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