GB2053158A - An adjusting device for sheet-fed rotary presses - Google Patents

Abstract

In a sheet-fed rotary printing press, adjusting gears 10, 11 of sheet trailing end grippers 12, 13 on a double sized drum cylinder T2, and the main driveshaft 1 of the cylinder T2 are connected to the main drive shaft 23 of a sheet reversing cylinder T3 via an adjustment flange 26 in order to facilitate the change-over from simplex to duplex printing and adjustment for various sheet formats. The flange 26 is secured to an end of the reversing cylinder main shaft 23. A principal adjusting gear 28 is positioned by a positioning pin 31 and disposed rotatably in the flange 26. A driving gear 32 meshed with a gear 30 on the impression cylinder of another printing unit is secured to the flange 26. A driving gear 22 is positioned by a positioning pin 37, disposed rotatably in the flange 26 and meshed with the driving gear on the main shaft 1. An idler gear 40 is meshed with the driving gear 22. A shaft 44 has secured to its end an intermediate adjusting gear 41 meshed with the idler gear 40, the shaft 44 being rotatably supported in the frames 4, 5. Gears 45, 46 are secured to the shaft 44 and meshed with the adjusting gears 10, 11. <IMAGE>

Description

SPECIFICATION An adjusting device for sheet reversing in a sheetfed rotary press This invention relates to an adjusting device for making proper adjustment corresponding to switching of the dual mechanism for one-side multi-colour printing and both-side printing and/or change in size of the printing sheet in a sheet-fed rotary press.

In the case of one-side multi-colour printing in a sheet-fed rotary press, it is possible to adjust the timing of printing of each printing unit by properly setting the printing starting points of the respective printing units in conformity to the leading end of the sheet being printed as the leading end of the sheet is held by the grippers of each sheet feeding cylinder for feeding of the sheet from the first to second printing unit, from the second to third printing unit and from the third to fourth printing unit. Also, there is required no specific adjusting means for change of size of the sheet being printed because the leading end of the sheet is always positioned forwardly in the direction of movement of the printing sheet.

However, in the case of both-side printing in the conventional sheet-fed rotary press, when the sheet P being printed is transferred from the double-sized drum cylinder T2 to the next reversing cylinderT3 (see Figures 1 and 2 of the accompanying drawings), not the leading end of the sheet P but the trailing end thereof is gripped, so that the grippers 8 holding the leading end of the sheet P on the double-sized drum cylinder T2 will not transfer the sheet at the sheet transfer point B to the reversing cylinderT3 but keep holding the sheet.The grippers 51 of the reversing cylinder T3 catch the trailing end of the printing sheet P held by the trailing end grippers 12, 13 of the double-sized drum cylinder T2 at the sheet transfer point B, while the grippers 8 holding the leading end of the sheet P on the cylinderT2, release it allowing the sheet to be moved backwards by the reversing cylinderT3 and be passed to the impression cylinder of the next printing unit II. In this case, therefore, there is required adjustment in accordance with the size of the sheet P. In other words, it is required to shift the relative phase of the first and second printing units I and II correspondingly to the size of the sheet being printed. One of the conventional adjusting methods in case of switching from oneside printing to both-side printing, or vice versa, is as follows.When the grippers 51 of the reversing cylinderT3 are moved around through an angle of about 180", since they do not meet the trailing end grippers 12, 13 ofthe double-sized drum cylinderT2 (a difference in the angle of H, in Figure 3 is produced), the grippers 12, 13 of the double-sized drum cylinder T2 are separated by loosening the fastening bolts which secure the grippers 12, 13 to the drive gear assembly, and then the reversing cylinderT3 is turned and set to the predetermined position and again bolted to the position. For this purpose, arrangement is made such that the drive gear assembly of the trailing end grippers 12, 13 can be adjusted by means of elongated slots.Thereafter, in order to adjust to the size of the sheet P, the drive gear assembly of the reversing cylinder T3 is turned so that the cylinder T3 and the trailing end grippers 12, 13 of the double-sized drum cylinderT2 will be allowed to move synchronously with each other.

Thus, this system has an advantage that synchronization between the reversing cylinderT3 and the trailing end grippers 12, 13 of the double-sized drum cylinderT2 is maintained, but because of one-side driving of the linking mechanism, irregularity tends to occur in the arrangements, and also it is required to provide stopper means on the trailing end gripper side for positioning the trailing end grippers 12, 13 at a location where they cause no impropriety to the maximal sheet size in the case of one-side printing. If the stopper means should contact with the main shaft or the leading end gripper (8) side, driving force will be transmitted to the trailing end grippers 12, 13 from both drive shaft of the double-sized cylinderT2 and driving gear thereof, so that it is instructed to provide a slight space for the stopper means.Thus, because the location for making adjustment relating to reversing of the grippers 51 of the reversing cylinderT3 and the location for adjustment conforming to size change of the sheet Pare fairly distant from each other, the operator is obliged to perform inconsistent operations. Adjustment also needs to be made of stopper spacing at the central part of the double-sized drum cylinder T2 in its axial direction.

In another sheet-fed rotary press, adjustment corresponding to reversing of the grippers 51 of the reversing cylinder T3 in association with the trailing end grippers 12, 13 of the double-sized drum cylinder T2 tends to be attended by an error from registering of the markings provided on the driving gear assembly of the reversing cylinder T3. Also, adjustment conforming to size change of the sheet P must be made by first clamping the trailing end grippers 12, 13 of the double-sized drum cylinderT2 from the machine side wall by another locking means after loosening the driving gear assembly of the reversing cylinderT3 and then adjusting the phase of the first printing unit I side to the predetermined sheet size.

Therefore, in this case, too, the adjusting locations are distant from each other and hence the working efficiency is poor. Also, if locking of the double-sized drum cylinderT2 is insufficient, the gripping tolerance of the sheet P received by the grippers 51 of the reversing cylinder T3 may be varied.

The object of this invention is to provide a sheet reversion adjusting device for a sheet-fed rotary press according to which the relative positions of the respective leading and trailing end grippers of the double-sized drum cylinder at the time of switching of the reversing grippers of the reversing cylinder from one-side printing to both-side printing, or vice versa, as well as the predetermined positions of the trailing end grippers of said cylinder at the time of one-side printing can be surely and correctly set.

As used hereinafter, the term "drive gear" is intended to include not only a gear meshingly engaged or engageable with another gear for transmitting drive thereto, but also a sprocket wheel engaged or engageable with another sprocket wheel via a chain for transmitting the drive thereto.

According to the invention there is provided an adjusting device for sheeting reversing in a sheet-fed rotary press having a double-sized drum cylinder equipped with sheet leading end grippers and sheet trailing end grippers angularly adjustable in the drum cylinder and a reversing cylinder angularly adjustable with respect to the drum cylinder and equipped with sheet grippers, the device comprising a flange drivingly engaged with a main shaft of the reversing cylinder, a first drive gear fixedly attached to the flange and drivingly engaged with a succeeding printing unit, a second drive gear adjustably attached to the flange and drivingly engaged with the trailing end grippers, a third drive gear adjustably attached to the flange and drivingly engaged with a main shaft of drum cylinder, and means for rotating the flange for adjusting the angular position of attachment of the second and third drive gears to the flange.

In a preferred embodiment the relative positions of the leading and trailing end grippers and the predetermined position of the trailing end grippers for one-side printing can be set by means of positioning pins. The reversing grippers and trailig end grippers of the double-sized drum cylinder are linked to each other through a series of gears and adjusting gear assembly. There takes place no deviation from the relative positions of both said grippers even in the event of a misoperation during adjustment in correspondence to size change of the printing sheet. Further, since the operating means for switching from one-side printing to both-side printing, or vice versa, are concentrated on the driving gears and flange thereof, the operator can make proper adjustment at one position with no need of repeatig standing and sitting for the machine operation.

To help understanding ofthe invention a specific embodiment thereof will now be described by way of example with reference to the accompanying drawings in which: Figure I is a schematic drawing of a two-color one-side/both-side printing press; Figures2 and 3 are enlarged sectional side views of a part of the double-sized drum cylinder; Figure 4 is an enlarged longitudinal sectional side view ofthe double-sized drum cylinder and reversing cylinder; and Figure 5 is an enlarged side view of the flange portion of the reversing cylinder.

Referring first to Figures 3,4 and 5, numeral 1 indicates the main shaft of the double-sized drum cylinder T2, the main shaft 1 being rotatablysupported by the bearings 2,3 in the frames 4, 5 on both sides. Also secured to the main shaft 1 are segment arms 6, 7 through which is rotatably supported a shaft 9 on which a plurality of grippers 8 adapted to hold the leading end of the sheet P being printed are mounted. Numerals 10 and 11 referto adjusting gears having rotatably supported therewith shafts 14, 15 on which a plurality of sheet pressing rolls 12 and sheet pulling rolls 13 constituting the grippers adapted to hold the trailing end of the sheet P are mounted.Secured to the adjusting gears 10, 11 by screws 18, 19 are segment arms 16, 17to which the trailing end grippers 12,13 are connected, these gears being also connected to the main shaft 1 so as to be rotatable relative thereto. 20 is a driving gear meshed with a series of driving gears 21,22, and secured to the main shaft 1.

Numeral 23 indicates the main shaft of the reversing cylinder T3, the shaft 23 being rotatably supported by the bearings 24, 25 in the frames 4, 5 at both ends. Secured to the main shaft 23 by a key 27 is a flange 26 to which a main adjusting gear 28 is secured by a positioning pin 31 and a screw 30 through a ring 29. Also secured to the flange 26 by a screw 33 is another driving gear 32 which is meshed with a gear 34 on the impression drum of the second printing unit II (see Figure 1). Further, the driving gear 22 is secured to the flange 26 by a positioning pin 37 and a screw 36 and through a washer 35.

There is also provided an adjusting shaft 39 rotatably supported by the frame 4 at one end and by an auxiliary bearing 38 at the other end, the adjusting shaft 39 having rotatably mounted thereon an idler gear 40 which is meshed with the main adjusting gear 28 and an intermediate adjusting gear 41 secured to a shaft 44 supported by the bearings 42,43 in the frames 4,5 at both ends. Mounted on the intermediate adjusting gear shaft 44 are the gears 45, 46 having the same number of teeth as the intermediate adjusting gear 41 and meshed with the adjusting gears 10, 11 respectively, of the doublesized drum cylinderT2. Secured to the adjusting shaft 39 is a pinion 47 meshed with the driving gear 32.48 and 49 denote sheet guides for the doublesized drum cylinderT2 and reversing cylinderT3, respectively.

Now, the operation of the device will be described.

Regarding first the positional relation of the grippers of the respective cylinders in the case of ordinary one-side multi-colour printing, the sheet trailing end gripper units 12, 13 of the double-sized drum cylinderT2 are positioned spaced apart from each other by a distance slightly greater than the maximal sheet size (see X in Figure 3). Such positioning can be effected by connecting the driving gear 22 and flange 26 by the positioning pin 37. Each reversing gripper assembly 51 of the reversing cylinderT3 has its shaft 50 biased to the rotating direction ofthe cylinderT3 as shown in Figure 3, and the leading end of the sheet P being printed is caught by operation of a separate cam control mechanism at the sheet transfer point B between the double-sized drum cylinder T2 and reversing cylinderT3. Positioning of each reversing gripper assembly 51 of the reversing cylinderT3 is effected by inserting the positioning pin 31 secured to the flange 26 into a socket 28a (see Figure 5) for one-side printing in the principal adjusting gear 28. Each of the sheet leading end grippers 8 of the double-sized drum cylinderT2 is arranged such that it is opened by a separate cam control mechanism 52,53 at the sheet transfer point B.

For switching this pattern of printing operation into both-side printing, first the reversing grippers 51 of the reversing cylinderT3 are turned around through an angle of about 180 by a separate cam control mechanism, then the screws 36,30 of the driving gear 22 and principal adjusting gear 23 are loosened and the positioning pins 37,31 are drawn out. Then a manual handle is secured to the adjusting shaft 39 and turned until the positioning pin 31 fits into another socket 28b for both-side printing.Thus, when the reversing gripper assembly 51 of the reversing cylinderT3 is turned around, there is produced an angular shift of H, between the reversing gripper assembly 51 and the correspond ingtrailing end gripper assembly 12,13 ofthe double-sized drum cylinderT2 as shown in Figure 3, so in order to correct such angular shift 01, the reversing gripper assembly 51, that is, the reversing cylinder T3 alone is shifted by an angle of 261. For this purpose, there are provided two sockets, one 28a for one-side printing and the other 28b for both-side printing, in the adjusting gear 28.By this operation, the driving gear 32 and hence the flange 26 are turned independently with the reversing gripper assembly 51 as the driving force is transmitted from the pinion 47 (the adjusting gear 28 will not turn as it stays loose), and when the positioning pin 31 similarly secured to the flange 26 fits into the socket 28b for both-side printing, the positions of the fore end of the reversing gripper assembly 51 and thesheettrailing end gripper assembly 12,13 ofthe double-sized drum cylinder T2 are automatically decided.

Then the manual handle is turned again to make adjustment to the length of the sheet P being printed, that is, a scale provided on the driving gear 22 and a reference point on the flange 26 are adjusted to the predetermined length of the sheet, whereby the sheet P held by the trailing end gripper assembly 12,13 of the double-sized drum cylinderT2 can be passed to the reversing gripper assembly 51 with a predetermined tolerance of holding via a separate cam control mechanism.By this operation, the sheet leading end grippers 8 of the cylinderT2 are opened by the cam control mechanism 52, 53. As the pinion 47 is turned by the manual handle, the adjusting gears 10, 11 and hence the sheet trailing end grippers 12, 13 of the double-sized drum cylinder T2 are changed in phase through the driving gear 32, flange 26, adjusting gear 28, idler gear 40, intermediate adjusting gear 41 and gears 45,46 while maintaining the same amount of movement as the reversing grippers 51 of the reversing cylinder T3. (The driving gear 22 will not turn as it stays loose during this operation). Also, during this operation, the second printing unit II connected to the reversing cylinderT3 is maintained in its correct positional relation by means of a series of driving gears 34 meshed with the driving gear 32.Therefore, in the case of both-side printing, the relative phases of the first and second printing units I and II are shifted according to the size of the sheet being printed.

Finally, the driving gear 22 and adjusting gear 28 are fastened by the respective fastening screws 36 and 30 through washer 35 to complete the operation of switching to both-side printing.

In case of effecting switching from both-side printing to one-side printing, first the fastening screws 36, 30 are loosened and the positioning pin 31 is pulled out. Then the pinion 47 is fitted and turned by the manual handle until the positioning pins 31 and 37 fit into the corresponding sockets 28a and 37a for one-side printing. When the positioning pins 31,37 are duly placed in the respective sockets, the fastening screws 30, 36 are fastened to complete the operation. Only one socket 37a (for one-side printing) is provided for the positioning pin 37.

Having the above-said structural arrangements, this embodiment according to the invention can produce the following effects.

(1) The regulated positions of the reversing grippers 51 of the reversing cylinder Ts relative to the sheet leading and trailing end grippers 8, 12 of the double-sized drum cylinder in case of switching from one-side to both-side printing, or vice versa, as well as the predetermined positions of the trailing end grippers 12, 13 of the double-sized drum cylinderT2 at the time of one-side printing can be surely and correctly set by the positioning pins 31, 37 Also, inadvertent failure to fasten the fastening screw 30 does not lead to any serious trouble. Thus, the operational safety of the device is secured.

(2) Since the reversing grippers 51 and the sheet trailing end grippers 12, 13 of the double-sized drum cylinder T2 are connected through a series of gears 28,40,41,45,46 and adjusting gears 10, 11, there takes place no derangement in the relative positions of both these grippers even if a misoperation is committed at the time of adjustment corresponding to a change in the sheet size. In other words, since the gear ratio of the principal adjusting gear 28 and the adjusting gears 10, 11 is set at 1:2 which is the same as the gear ratio of the driving gears 32, 20, the sheet trailing end grippers 12, 13 of the double-sized drum cylinder T2 turn at the same speed as the sheet leading end grippers 8 and hence no divergence is caused in the movements of these grippers. Also, because of driving on both sides, there takes place no derangement and smooth rotation is ensured.

(3) Since the operations for switching from oneside printing to both-side printing, or vice versa, are concentrated to the driving gear 22 and its flange 26, the operator can perform his work at one position with no need of repeating standing and sitting for making the operational adjustment. Also, only two types of tools (fastening wrench and manual handle) are required for the operation and all the operations involved are consistent.

Attention is drawn to co-pending application No.

8014395 which describes in more detail and claims the trailing end grippers.

Claims (8)

1. An adjusting device for sheeting reversing in a sheet-fed rotary press having a double-sized drum cylinder equipped with sheet leading end grippers and sheet trailing end grippers angularly adjustable in the drum cylinder and a reversing cylinder angularly adjustable with respect to the drum cylinder and equipped with sheet grippers, the device comprising a flange drivingly engaged with a main shaft of the reversing cylinder, a first drive gear fixedly attached to the flange and drivingly engaged with a succeeding printing unit, a second drive gear adjustably attached to the flange and drivingly engaged with the trailing end grippers, a third drive gear adjustably attached to the flange and drivingly engaged with a main shaft of drum cylinder, and means for rotating the flange for adjusting the angular position of attachment of the second and third drive gears to the flange.

2. An adjusting device as claimed in claim 1 wherein the flange is fixedly attached to the main shaft of the reversing cylinder.

3. An adjusting device as claimed in claim 1 or claim 2 wherein the second drive gear is rotationally adjustable with respect to the flange from one position for one side printing to another position for double-side printing, two sockets being provided in the second drive gear for engagement bya pin engageable in the flange, one socket locating the one position and the other socket locating the other position and locking means being provided for locking the second drive gear in either position.

4. An adjusting gear as claimed in claim 1, claim 2 or claim 3 wherein the third drive gear is rotationally adjustable with respect to the flange from a position for maximum sheet length and one side printing to a variable position for varying sheet length and double-side printing, one socket - locating the maximum sheet length position - being provided in the third drive gear for engagement by a pin engageable in the flange, a scale being provided for locating the variable position and locking means being provided for locking the third drive gear in position.

5. An adjusting gear as claimed in any preceding claim wherein the trailing end grippers are supported at both sides of the drum cylinder and drive gear means drivingly connected to the second drive gear is provided for both driving the trailing end grippers at both sides of the drum cylinder.

6. An adjusting device for sheet reversing in a sheet-fed rotary press comprising a main shaft of a double-sized drum cylinder, adjusting gears disposed on either side of the drum cylinder and mounted rotatably on the main shaft, sheet trailing end grippers mounted on shafts passed rotatably through the adjusting gears, a main shaft of a reversing cylinder, a flange secured to an end of the reversing cylinder main shaft, a principal adjusting gear positioned by a positioning pin and disposed rotatably in the flange, a driving gear meshed with a gear on the impression cylinder of another printing unit secured to the flange, a driving gear positioned by a positioning pin and disposed rotatably in the flange and meshed with the driving gear on the main shaft, an idler gear meshed with the driving gear, a shaft having secured to its end an intermediate adjusting gear meshed with the idler gear, the shaft being rotatably supported in the frames, gears secured to the shaft 44 and meshed with the adjusting gears, and a pinion secured to an adjusting shaft engaged with the driving gear.

7. An adjusting device as claimed in claim 6 including segment arms provided rotatably on the main shaft and spaced apart from each other inside the adjusting gears, and sheet leading end grippers mounted on a shaft passed rotatably through the segment arms.

8. An adjusting device for sheet reversing in a sheet-fed rotary press substantially as hereinbefore described with reference to the accompanying drawings.