US3455547A

US3455547A - Drive mechanism for sheet turning device in multicolor printing machines

Info

Publication number: US3455547A
Application number: US652753A
Authority: US
Inventors: Otfried Rudolph; Gunter Lucius
Original assignee: Planeta Druckmaschinenwerk AG
Current assignee: Planeta Druckmaschinenwerk AG
Priority date: 1967-07-12
Filing date: 1967-07-12
Publication date: 1969-07-15
Anticipated expiration: 1986-07-15

Description

July 15, 1969 o. RUDOLPH ETAL 3,455,547

DRIVE MECHAN FOR SHEET TURNING DEVICE IN MULTI OR PRINTING MACHINES Filed July 12, 1967 3 Sheets-Sheet 1 INVENTORS OTFR RU DOL PH GUNT LU CIUS July 15, 1969 o. RUDOLPH ETAL 3,455,547

DRIVE MECHANISM FOR SHEET TURNING DEVICE IN MULTIGOLOR PRINTING MACHINES Filed July 12, 1967 3 Sheets-Sheet 2 N INVENTORS 5 OIFRIED RUDOLPH GUNTER LUCIUS 3,455,547 T '1 R ING DEVICE IN NG HINES July 15, 1969 o. RUDOLPH ETAL DRIVE MECHAN F HEE MULTI O NTI Filed July 12. 1967 3 Sheets-Sheet 5' FIG.

INVENTORS OIFRIED RUDOLPH GUNTER LUCIUS 3,455,547 DRIVE MECHANISM FOR SHEET TURNING DE- VICE IN MULTICOLOR PRINTING MACHINES Otfried Rudolph, Dresden, and Giinter Lucius, Boxdorf, Germany, assignors to VEB Druckmaschlnenwerk Planeta, Radebeul, Germany Filed July 12, 1967, Ser. No. 652,753

Int. Cl. B65h 29/06 US. Cl. 27182 6 Claims ABSTRACT OF THE DISCLOSURE Disclosed is a drive mechanism for a pair of sheet turning grippers operatively arranged on a sheet transfer cylinder. The grippers are coupled one to another by two gear segments. A profiled cam is fixedly disposed close to the surface area of the side wall of the transfer cylinder. A cam follower rocker is urged by first spring means to follow the circumference of the cam and linked by an intermediate coupling arm to one of the grippers to force the coupled grippers into a swing-in position when the cam follower rocker travels on the lower .profile of the cam. A second spring means urges the coupled grippers into a swing-out position when the cam follower travels on the elevated profile of the cam and relieves the tenslon in the coupling arm. Locking means are provided at one of the gear segments to optionally lock the grippers in their swing-out .position.

The present invention relates to a drive mechanism for a sheet turning device in multicolor rotary printing machines with successive printing units having a sheet transport cylinder therebetween, and being in a cooperative relationship one to another.

It is known how to turn a sheet between two successive printing units in a rotary multicolor printing machine for the purpose of printing the reverse side of the sheet.

There are known embodiments wherein two gripper sets which are eccentrically arranged on the sheet transport cylinder are swung toward the center of the transfer cylinder and toward each other at the point of sheet transfer in order that the sheet delivery from the first set of grippers to the second set might be accomplished. After the sheet has been delivered, both gripper sets are swung to their original position again and the turned sheet is delivered to the following cylinder. Each of these grippers, is fixedly mounted on a swing shaft which is pivotably Supported on the transfer cylinder and mounted eccentrically and parallel to the axis of the latter. A swing drive which is correlated to each set of grippers comprises: A hub pinion gear fixed to the end of each swing shaft, respectively, the gear teeth of which are engaged with a gear segment. The gear segment is supported on a pivot which is mounted on the side disc of the transfer cylinder. The latter pivot supports also a cam follower rocker having a rotary roll follower at its end. This roll follower is, during the rotation of the sheet transfer cylinder, in a slidable contact with a stationary cam disposed for cooperation with a roll follower. The gear segment is counterclockwise urged by means of spiral springs which are mounted on the side disc of the transfer cylinder. An ad justable limit stop is seated on the gear segment to limit the counterclockwise pivoting of the cam follower rocker, the pivotal motion of which results due to the action of a pressure spring disposed between the gear segment and the cam follower rocker. A limit stop for the hub pinion gear seating on the side disc of the transfer cylinder, limits pivoting of the swing shaft in the clockwise direction. Another adjustable limit stop limits the pivoting of the swing shaft in the counterclockwise direction.

nited States Patent Patented July 15, 1969 Therefore, during the motion of the cam follower rocker in the clockwise direction, the springs move the gear segment in the clockwise direction against the pressure of the spiral springs and, simultaneously, the gear segment is pivoted in the clockwise direction so that the hub pinion gear pivots counterclockwise the swing shaft ab out its axis.

If the sets of grippers should not swing during the rotation of the sheet transfer cylinder, which requirement may be, for example, in the case of printing on the obverse side of the sheet, then as a consequence of the cinematic structure of the swing drive, it is necessary to remove the cam disposed within the orbit of the roll follower in order that during the rotation of the transfer cylinder the roll follower might circulate without obstacles on a circular path.

The shortcoming of the aforementioned swing drive is that each of the both sets of grippers is driven by a sep arate swing drive.

A separate drive for each of the gripper sets represents, however, an expensive technical design and installation, requiring a considerable amount of material.

Especially in case of large sheet transfer cylinders upon which two sheet turning systems and consequently four sets of grippers are arranged, the installation of separate swing drives for the four respective sets of grippers is, owing to the insufficient room on the side disc surface and in axial direction thereof particularly disadvantageous.

It has been tried to adjust by means of fixed and adjustable limit stops the exact position of the gripper sets during seizing of the sheet, during transferring the sheet from the first gripper set to the second gripper set, and during transferring of the sheet to the grippers of the gripping system on the following cylinder. Due to the effect of the limit stops and the effect of the pressure springs, a backlash of the gear teeth flanks occurs in the hub pinion gears and consequently a smooth operation of the machine, particularly at increased speeed, cannot be guaranteed, so that the capacity of the printing machine is limited for lower speeds only. If the sets of grippers should not swing during multicolor first form printing, then the cam, lying inside the circular path of the follower, has to be removed. Due to the unfavorable room conditions, the demounting of the cam is very difficult and time-consuming; when adjusting the cam one has to take care to place the cam exactly to its original position.

The object of this invention is to reduce the technical and operational disadvantages for the prior art swing drive of the sheet turning systems, so that particularly the material consumption and cost of production are reduced.

A further object of this invention is to improve the technical and operational design of the drive mechanism for sheet turning devices and to increase the efiiciency of the printing machine, in spite of reduction of the installation expenses.

Still a further object of this invention is to shorten the time needed for the cam re-adjustment and to simplify the change-over from the obverse side printing adjustment to the adjustment for the printing on the reverse side of the sheet so that an increase of the productivity of the printing machine can be attained.

The purpose of the present invention is to carry out the motional processes of the sheet turning device by means of a single swing drive only which drive is particularly applicable for a transfer cylinder with a twofold increased diameter. Another purpose of this invention is to carry out a swing drive having a simple cinematic structure.

In accordance with the present invention, the above objects are attained so that the known sheet turning systems are linked one to another by means of gear seg- 3 ments or by a couple for a guided motion, biased by means of springs, and driven by means of a four-bar linkage, preferably in the form of a double rocker.

The roll follower is so adjusted that the sheet turning systems are swung out when the roll follower is on the respective highest point of the curved circumference of the cam. The roll follower is urged against the curved cam circumference by a torsion-bar spring.

In order that the present invention may be readily carried into effect, it will now be descibed with reference to the accompanying drawings, wherein:

FIG. 1 shows a schematic view of the swing drives according to the present invention, applied for two sheet turning devices of a sheet transfer cylinder between two printing units, whereby the sheet turning grippers are coupled one to another and positively actuated by means of gear segments;

FIG. 2 shows schematically a sectional view, taken along line AA of FIG. 1, of a swing drive and of suction grippers;

FIG. 3 shows schematically a sectional view, taken along line BB of FIG. 1, of a swing drive and of mechanical grippers.

FIG. 4 shows a schematic side view of a swing drive for a sheet turning device whereby the sheet turning grippers are linked together for positive motion by means of a coupling arm; and

FIG. 5 shows schematically the adjustment of the sheet turning device in a locked swungout position.

As shown in FIG. 1, two sheet turning devices are arranged on a sheet transfer cylinder 1 having a twofold diameter with respect to cooperating press cylinders (not shown) whereby the first sheet turning device is in a swung-in position, and the second sheet turning device is in a swung-out position. Each two

sheet turning grippers

2, 3 and 4, 5 respectively, represent a sheet turning device. In this embodiment of the invention, the sheet turning grippers 2 and 4, are carried out as suction grippers and, on the other hand, the sheet turning grippers 3 and 5 have the form of mechanical grippers.

The sheet turning

grippers

2, 3 and 4t, 5 respectively, are fixedly arranged on

pivots

6, 7, 8 and 9, which are suitably journaled in the side wall or disc of the sheet transfer cylinder 1. On each end of the

pivots

6, 7, 8 and 9 respectively,

gear segments

10, 11, 12 and 13 are afiixed in such a manner that the gear segments pertaining to separate

sheet turning devices

2, 3 and 4, 5 are engaged one to another for a positively actuated motion. The device mechanism for swinging out and in the two pairs of grippers in a predetermined time relationship is in accordance with the present invention carried out as follows:

Cam follower rockers

14 and 15 are pivotably supported on

pivots

16 and 17, respectively. The cam follower rockers 14 (and 15) and the gear segments 10 (and 12) are pivotably linked, according to one feature of the present invention, by means of

jointed coupling arms

18 and 19, respectively. The

jointed coupling arms

18 and 19 are connected by

pin joints

20 and 21 to the

cam follower rockers

14 and 15 and by means of

pin joints

22 and 23 to the

gear segments

10 and 12, respectively.

The respective

cam follower rockers

14 and 15,

coupling arms

18 and 19, and

gear segments

10 and 12 owing to the engagement of their teeth, constitute for each gripper in one sheet turning device a four-joint linkage which thus represents a synchronized double rocker member.

The coupling between the swinging

cam follower rockers

14 and 15, and the sheet turning grippers 2 and 4 is in this manner produced by means of simply shaped

coupling arms

18 and 19 only. Furthermore, since both

sheet turning grippers

2, 3 and 4, 5 are engaged together by

gear segments

10, 11, and 12, 13, so for driving of a. sheet turning device only one four-joint linkage, working as a double rocker, is necesary.

A drive for a sheet turning device can be also carried out, for example, as a four-joint linkage having the form of a crank-guide.

It is also possible to connect positively the

sheet turning grippers

2, 3 and 4, 5 one to another by means of a coupling rod 43 (FIG. 4). For this purpose, the coupling rod 43 links, for example, the swing lever 44 which is rigidly mounted on a pivot 6, and swing lever 45 rigidly connected to the pivot 7.

To force the geared grippers in one sheet turning device into a swing-out position, pushing

springs

32 and 33 bias each pair of grippers into the radial direction. The

springs

32 and 33 are disposed on supporting

rods

26 and 27 which at one end are hinged to respective levers 24 and 25 aflixed on pivots 7 and 9. The opposite end portions of

rods

26 and 27 are slidably guided in guide members 30 and 31 rigidly connected to the side wall of the transfer cylinder 1:

Springs

32, 33 span the entire drive in any position of the sheet turning devices 2, 3 and 3, 4 so that the backlash of the entire swing drive, caused by the production inaccuracy, is neutralized by means of forces which act always in the same direction. The teeth backlash canot consequently occur. If the pivots 7,9 are produced, for example, as hollow shafts, then the

springs

32, 33 can be substituted by torsion bar springs disposed within the corresponding hollow shaft.

Roll

followers

34, 35 are pivotably supported in the

cam follower rockers

14, 15, respectively (FIGS. 1 and 2). The

roll followers

34, 35 travel during the rotation of the sheet transfer cylinder 1, on the curved circumference 36 of cam 38 fixedly mounted to the frame wall 37 of the printing machine, so that the swinging movement

cam follower rockers

14, 15 and consequently, the positions of the

sheet turning devices

2, 3 and 4, 5 are controlled in dependence on the shape of the cam circumference 36. The jointed

coupling arms

18 and 19 are mounted on the

cam follower rockers

14, 15 in such a manner that the

sheet turning devices

2, 3 and 4, 5 are, due to the action of

springs

32 and 33, in a swung-out position when the

roll followers

34, 35 are travelling over the elevated area of the curved circumference 36. In case of printing, on the obverse side of the sheets, the sheet turning grippers 3, 5 are arrested in the swung-out position by means of screw 39 (FIG. 5). The screw 39 firmly connects the sheet turning devices 3 and 5 with a rail 40 which is fixedly mounted in the sheet transfer cylinder 1. In such a simple manner, only by fixing a locking member into a positively coupled swing drive, the swing motion of the

sheet turning systems

2, 3 and 4, 5 is made inoperative. For this reason, it is not necessary to demount the cam or other drive members for blocking the swing motion of the

sheet turning devices

2, 3 and 4, 5. The slidable contact of the roll follower 34 with the cam circumference 36 is safeguarded by means of a torsion-bar spring 41. The torsion-bar spring 41 is at one end fixed to the cam follower rocker 14 and at the other end to a spring collet 42. The effects of the torsion-bar spring 41 and of the spring 33 are supplementary one to another. The roll follower 35 is forced against the cam circumference 36 in the same manner as the roll follower 34.

The turning of sheets is carried out in conventional manner at the points of contact between the cylinders of cooperating printing units (not shown) and the transfer cylinder 1. The trailing edge of the sheet to be turned over is grasped at a contact point by means of suction gripper 2, for example, which in FIG. 1 is shown in a swing-out position, i.e., in alignment with the radius of the side wall of the transfer cylinder 1.

At the moment when the suction gripper 2 has grasped thetrailing edge of the sheet, the leading edge of the latter is released from grippers on the impression cylinder and the sheet is carried in counterclockwise direction by the transfer cylinder 1. As soon as the cam follower rocker 14 enters the lowered section on the cam circumference, the geared grippers 2 and 3 are forced, due to the action of the spring 41 and of the jointed coupling arm 18, into the swing-in position. In the latter position the sheet is released from the suction gripper 2 and grasped by the mechanical gripper 3. Subsequently, the rocker 14 enters the elevated section of the cam circumference, the grippers swing open and the turning of the sheet is accomplished. During the further rotation of the transfer cylinder, the reversed sheet is delivered in a known manner to the adjacent cylinder of the following printing unit.

What is claimed is:

1. In a multicolor rotary printing machine having successive printing units with a sheet transfer cylinder therebetween, at least a sheet turning device operatively disposed on the transfer cylinder and having a first and second gripper means supported on pivots respectively journalled in the side wall of said transfer cylinder, a drive mechanism for said sheet turning device, comprising: gripper coupling means for positively imparting the motion of said first gripper to said second gripper, profiled cam means fixedly disposed close to central area of said side wall, cam follower rocker means journalled at one end to said side wall, first spring means for urging said cam follower rocker means against the profiled circumference of said cam means, the opposite end of said cam follower rocker being coupled to the first one of said grippers by means of a jointed coupling arm for forcing said grippers into a swing-in position when said cam follower rocker travels in the lowered profile section of said cam means, and second spring means coupled to the second one of said grippers to force said grippers into a swingout position during the travel of the cam follower rocker in the elevated section of said cam means.

2. In the printing machine according to claim 1 wherein said gripper coupling means comprises two gear segments respectively fixed to said pivots and being in engagement one to another for a positively actuated motion.

3. In the printing machine according to claim 1 wherein said coupling means comprise a first lever affixed to the pivot of said first gripper, a second lever affixed to the pivot of said second gripper, and a coupling rod hinged between said first lever and said second lever to provide a double rocker four-joint linkage.

4. In the printing machine according to claim 1 wherein said second spring means comprise a torsion bar spring arranged coaxially within the hollow pivot of said second gripper. Y

5. In the printing machine according to claim 1 wherein said cam follower rocker is urged against said cam circumference by means of a tension bar spring mounted parallel to the axis of said transfer cylinder.

6. In the printing machine according to claim 1, lock means comprising a rail fixedly mounted to the sheet transfer cylinder for arresting the sheet turning device in the swing-out position by means of a screw.

References Cited UNITED STATES PATENTS 2,757,610 8/1956 Gegenheimer 101-183 EDWARD A. SROKA, Primary Examiner