Printing – Flexible-sheet-securing devices
Reexamination Certificate
1999-09-14
2001-06-05
Asher, Kimberly (Department: 2854)
Printing
Flexible-sheet-securing devices
C101S378000
Reexamination Certificate
active
06240845
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to rotary printing machines, and more particularly to a device for fastening flexible printing plates within rotary printing machines.
2. Description of the Related Art
DD 261 765 A1 describes a device for fastening flexible printing plates to a plate cylinder or rotary printing machines. A channel in the plate cylinder accommodates the bent ends of the printing plate. A bore in the channel, which is axially parallel to the plate cylinder, has two segmented shafts arranged pivotably therein. Leaf springs which are each fastened to the segmented shafts can be brought into contact with the ends inserted into the channel. The segmented shafts are mounted in the bore in the channel via a hollow shaft which is cut out for the leaf springs. The leading end of the ends which are bent at different acute angles depending on the direction of rotation of the plate cylinder is clamped directly by the leaf springs against an oblique channel side wall, and the trailing end is clamped between the leaf springs and a clamping bar fastened to the hollow shaft. This device depends on the direction of rotation, has a relatively wide channel opening on the periphery of the plate cylinder due to the double mounting of the segment shafts in the bore, requires a correspondingly high outlay, and is not suitable for the use of a device for automated printing-plate changing.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a device for fastening flexible printing plates to a plate cylinder which secures the ends of the printing plate in the channel, even at a high speed of revolution of the plate cylinder, and ensures a printing-plate change which looks after the printing plate in the sense of its recyclability. It is another object to provide a device for fastening flexible printing plates to a plate cylinder that is simply constructed, is not susceptible to faults, can be used irrespective of the direction of rotation of the plate cylinder and is suitable for automatic printing-plate change.
This and other objects of the invention achieved by securing the bent ends of the printing plate against slipping out of the channel by means of a positive and frictional connection produced by the interaction of the shaped elements, recesses and the leaf springs, even at a high circumferential speed of the plate cylinder. Because of its radially symmetrical construction, the device according to the invention can be used irrespective of the direction rotation with respect to the plate cylinder, and in conjunction with the rectangularly bent ends of the printing plate. Since the insertion and withdrawal of both ends always takes place at the same angle, namely at right angles to the plate cylinder, and does not require any change in the direction of rotation of the latter the device of the present invention is suitable for automatic printing-plate changing. In addition, the printing plate is not damaged during the changing operation, ensuring its multiple use.
The interaction during a printing-plate change of shaped elements having a relatively low height, together with the recesses in the channel, makes possible a narrow channel gap on the periphery of the plate cylinder which benefits the printing process by minimizing channel impacts. Finally, the direct arrangement of the segmented shafts in the bore of the channel ensures a simple construction of the device, and the indirect support of the segmented shafts via supporting elements in conjunction with the large clearance between the segmented shafts and the bore, ensures low susceptibility to faults with regard to the mobility of the mechanisms as a result of contamination getting into the channel.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.
REFERENCES:
patent: 3408933 (1968-11-01), Hermach et al.
patent: 5423258 (1995-06-01), Weber
patent: 2 711 095 (1994-10-01), None
patent: 1 274 180 (1972-05-01), None
patent: 2 010 182 (1979-06-01), None
Asher Kimberly
Cohen & Pontani, Lieberman & Pavane
MAN Roland Druckmaschinen AG
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