US3366048A

US3366048A - Cylinder interrupter for a rotary offset printing and duplicating machine

Info

Publication number: US3366048A
Application number: US451772A
Authority: US
Inventors: Erich Gericke
Original assignee: Rotaprint GmbH
Current assignee: Rotaprint GmbH
Priority date: 1964-05-08
Filing date: 1965-04-29
Publication date: 1968-01-30
Anticipated expiration: 1985-01-30
Also published as: GB1075888A; DE1253726B; CH428782A; AT267554B; NL6505784A

Description

Jam. 30, 1968 E. GERICKE 3,365,043

' CYLINDER INTERRUPTER FOR A ROTARY OFFSET PRINTING AND DUPLICATING MACHINE Filed April 29, 1965 2 Sheets-Sheet 1 Jan. 30, 19 68 EGERlCKE 3,366,048 CYLINDER INTERRUPTER FOR A ROTARY OFFSET PRINTING AND DUPLICATING MACHINE Filed April 29, 1965 2 Sheets-Sheet 2 inventor:

United States Patent Office 3,366,048 Patented Jan. 30, 1968 r 3,366,048 CYLINDER INTERRUPTER FOR A ROTARY OFF- SET PRINTING AND DUPLICATING MACHINE Erich Gericke, Berlin-Steglitz, Germany, assignor to.

Rotaprint Gesellschaft mit beschrankter Haftung, Berlin, Germany Filed Apr. 29, 1965, Ser. No. 451,772 Claims priority, application Germany, May 8, 1964, R 37,853 3 Claims. (Cl. 101-218) ABSTRACT OF THE DISCLOSURE In an offset printing and duplicating machine the plate cylinder is mounted on an eccentric shaft. Control means are associated with the eccentric shaft so that by a deflection thereof the eccentric shaft is rotated so that the plate cylinder is first brought into contact with the inking roller and then with the offset cylinder. The plate cylinder is moved in reverse sequence when the elements are moved to the inoperative position.

This invention relates to an offset printing and duplicating machine comprising an inking system and a plate cylinder rotatably mounted on an eccentric shaft.

Offset printing machines known to the art are so constructed that all the cylinders are separated from one another and that the plate cylinder is separated from the inking system when the machine is not in operation. When the machine is started up and the rollers of the inking system have picked up ink, the inking roller of the inking system is first moved into contact with the printing plate on the printing'cylinder until the plate has been evenly inked. The plate cylinder and the offset cylinder are then moved into contact for transferring the inked printing image to the rubber blanket of the offset cylinder. As soon as the rubber blanket has accepted enough ink and the sheet upon which the impression is to be made has been fed into the gap between the offset cylinder and the impression cylinder the two latter cylinders are likewise moved into contact to transfer the image from the rubber blanket to the paper upon which the image is to be printed.

This form of construction has the drawback that separate control means are needed for moving the inking rollers and the plate cylinder in the manner required and that two separate control means must therefore also be operated. Particularly in the case of machines which are required to print short and very short runs comprising as few as copies, these operations must be performed whenever the machine is started and stopped at intervals of a few minutes. This obviously taxes the attention of the operator controlling the printing machine and faulty manipulations are therefore likely to occur.

The object contemplated by the invention is therefore the provision of a form of construction in which these operations are considerably simplified and faulty manipulation is less likely to occur.

According to the invention it is therefore proposed to utilise the manner in which the plate cylinder is mounted on an eccentric shaft, which as such is conventional, by providing the eccentric shaft with control means adapted by its deflection to rotate the eccentric shaft in such a Way that the printing plate of the plate cylinder is first brought into contact with the inking roller and then with the offset cylinder, the plate cylinder moving in the converse sequence when the cylinders and the inking system are moved apart.

An embodiment of the invention will be described by reference to the accompanying drawings in which:

FIG. 1 is a side elevation of the machine in the position in which the control lever is in the off position;

FIG. 2 is a view of the eccentric shaft and of the control mechanism mounted thereon (view A);

. FIG. 3 is a view from above showing the mobility of the arresting notches (view B), and

FIG. 4 is a front view illustrating the deflection of the arresting notches by the withdrawal of the impression cylinder (view C).

FIGURE 1 illustrates the shift mechanism in the off position, that is to say the eccentric shaft 1 is held by control lever 2 in a position in which the plate cylinder 3 mounted on the eccentric shaft does not make contact either with the

inking rollers

4 and 5 or with the offset cylinder 6.

In this position the rubber blanket 7 of the offset cylinder 6 can be washed, and the inking system containing the

inking rollers

4 and 5 cleaned and re-inked. When the rubber blanket is clean and the inking rollers have been re-inked, plate cylinder 3, offset cylinder 6 and impression cylinder 8 can be started. By now moving control lever 2 into the position ink, as shown in FIG- URE 3, the lever 2 can be made to snap into the arresting notch marked ink in virtue of its inherent elasticity and it will be retained in this notch ink by the pull of spring 9 which normally urges the shift mechanism to the off position. Plate 10 of the plate cylinder 3 is thereby moved into contact with inking roller 4 and the plate 10 is inked without as yet having made contact with the rubber blanket 7 of the offset cylinder 6. This position of the plate cylinder 3 is marked in dot-dash lines in FIGURE 1.

When the plate 10 has been sufficiently inked, lever 2 is transferred into position print and as described with reference to position ink the lever will now engage the notch marked print. In this operating position which is indicated in dotted lines in FIGURES 1 and 3, plate 10 makes contact both with the inking roller 5 and with the rubber cloth 7 of the offset cylinder 6. Consequently ink is transferred to the rubber blanket 7. When the leading edge of the paper sheet 11 that is to be printed upon has been presented to the gap between offset cylinder 6 and the impression cylinder 8 in a manner that is well understood and therefore requires no special description the impression cylinder 8 is tilted by its eccentric shaft 12 into contact with the offset cylinder 6, likewise in conventional manner either by hand or mechanically, so that the printing of the sheet feeding between the two cylinders can proceed.

When at the end of the printing operation the impression cylinder 8 is manually or mechanically withdrawn, a projection 15 which is provided on the eccentric shaft 12 of the impression cylinder 8, and which engages a recess 13 in draw bar 14, retracts the latter in the downward direction against the resistance of a spring 16 until the projection 15 rides out of recess 13, releasing the drawbar 14 for return by spring 16 into contact with an intercepting pin 17. The downward motion of the draw bar causes a wedge-shaped cam 18 at the upper end of draw bar 14 to deflect a co-operating cam 20 on notched bar 19 against the resistance of a spring 21 in such manner that the notched bar 19 is pivotably deflected about its pivot 22, thereby withdrawing the notch marked print or the notches marked print and ink from control lever 2 which is therefore released and restored by spring 9 to the off position. Consequently the plate cylinder 3 is lifted off the offset cylinder 6 and with drawn from the

inking rollers

4 and 5. All the printing cylinders and the inking rollers are therefore out of mutual contact. In other words, the machine is in inoperative position.

If the machine is to restart printing, control lever 2 must be operated as above described.

Those skilled in the art will appreciate that various modifications to the embodiment described are possible and that the invention may be otherwise embodied without departure from the spirit and scope of the invention.

1 claim:

1. An offset printing and duplicating machine comprising an inking system having at least one inking roller, an eccentric shaft, spring means normally biassing said eccentric shaft into an initial position, a plate cylinder rotatably mounted on said eccentric shaft, an offset cylinder, a control lever defiectable about the axis of said eccentric shaft having an inherent springiness in the direction normal to its direction of deflection, said inking roll and offset cylinder being spaced slightly from and extending parallel to said plate cylinder in inoperative position, said eccentric shaft when rotated bringing said plate cylinder successively into contact with said inking roll and said offset cylinder, said control lever being carried by said eccentric shaft and adapted upon deflection to rotate said shaft to displace said shaft and said plate cylinder from said initial position against the restoring force of said biassing spring means, and a pivotally mounted bar having a plurality of retaining notches into which said inherently springy control lever is adapted to latch to retain said control lever in at least a first deflected position in which said plate cylinder is positioned 4, in contact with said inking roller and at least a second deflected position in which said plate cylinder is positioned in contact also with said offset cylinder.

2. An ofiset printing and duplicating machine as set forth in claim 1 comprising a paper feed means, and lever transmission means adapted to respond to discontinuance of operation of said paper feed means to with draw at least said retaining notch associated with said second deflected position of said control lever to release said control lever whereby said biassing spring means restores said plate cylinder to its said initial position.

3. The offset printing and duplicating machine according to claim 2 wherein said lever transmission means is adapted to withdraw all said retaining notches.

References Cited UNITED STATES PATENTS 2,026,434 12/1935 Quick et al. 101247 2,261,913 11/1941 Davidson et al. l01-2l8 2,839,992 6/1958 Morse l012l8 2,860,577 11/1958 Fowlie 10l-218 3,046,881 7/1962 Jurny 1012l8 3,203,346 8/1965 Norton et al. 1012l7 ROBERT E. PULFREY, Primary Examiner.

J. R. FISHER, Assistant Examiner.