US2261305A - Means for attaching printing plates to plate cylinders of printing presses - Google Patents

Description

Nov. 4, 1941. A. w. STEPHENSON 2,261,305

\ MEANS FOR ATTACHING PRINTING- PLATES TO PLATE CYLINDERS OF PRINTING PRESSES Filed Sept. 5, 1959 IN VE 1V T 01? AEL/NGTON W J 7' E PHENSON I A TTORNE Y Patented Nov. 4, 1941 MEANS FOR ATTACHING PRINTING PLATES TO PLATE CYLINDERS PRESSES F PRINTING Arlington W. Stephenson, Arcadia, Calif., as-

signor to Lenzart, Inc., San Francisco, Calif., a corporation of California Application September 5, 1939, Serial No. 293,312

2 Claims.

This invention relates in general to printing plates and more particularly to means for securing printing plates of sheet metal form to the plate cylinders of a printing'press.

Although there is considerable advantage in using printing plates of sheet metal form, much difiiculty has been experienced in properly securing plates of this character to a plate cylinder or to an intermediate dummy or mounting cylinder.

In general, the object of this invention is the provision of means for securing or attaching a sheet metal printing plate to a dummy cylinder or other base member so that there is absolute surface contact between these two members and so that there will be no creepage of the printing plate on the base member as a result of the printing operation.

More specifically, the object of this invention is the provision of means whereby a sheet metal printing plate may be held under tension in surface contact with a dummy cylinder or other base member.

The invention possesses other advantageous features, some of which with the foregoing will be set forth at length in the following description where that form of the invention which has been selected for illustration in the drawing accompanying and forming a part of the present specification is outlined in full. In said drawing, one form of the invention is shown, but it is to be understood that it is not limited to such form, since the invention as set forth in the claims may be embodied in a plurality of forms.

Referring to the drawing:

Figure l is a transverse section taken through a dummy cylinder to which a sheet metal printing plate has been attached in accordance with my invention.

Figure 2 is an elevation with parts broken away of a plate cylinder carrying a pair of dummy cylinders to which a sheet metal printing plate has been attached in accordance with the objects of my invention as more clearly shown in Figures 1 and 3.

Figure 3 is a section taken on the line 33 of Figure 2.

Figure 4 is a partial end elevation taken on the line 44 of Figure 2.

As shown in these figures, the objects of my invention are embodied in a semicylindrical dummy or mounting plate I preferably made of steel and having considerable resiliency or elasticity so that when its ends are outwardly sprung as shown in Figure 1, and then released, they will immediately return to their normal position. Milled on the inner surface of the dummy l are a plurality of circumferentially space longitudinally extending grooves 2 which due to the fact that the gauge of the metal has been decreased at these points, make it easier to spring the ends of the dummy. The depth of successive grooves should increase from the center of the dummy to its ends.

Formed on each end of the dummy is a longitudinally extending beveled tongue 3 provided along its inner surface with a shoulder 4 and along its outer beveled face with teeth or serrations 5. Secured over the tongue 3 by screws 6 is a lock strip 1 formed with a longitudinally extending groove 8 conforming to thecontour of the tongue and provided with a shoulder 9 opposed to the shoulder 4 of the tongue. Clamped between the lock strip 1 and the serrated surface of the tongue 3 is the end of a sheet metal printing plate H which for example may be in the form of a relief, intaglio, or planographic plate. The dimensions of the tongue 3 and groove 8 are such that when the printing plate is secured between the tongue and lock strip, the outer exposed surface of the lock strip 1 forms a continuation of the cylindrical surface of the printing plate surrounding the dummy I,

In utilizing this device to secure a sheet metal printing plate in absolute contact with the dummy, one end of the printing plate is attached to one end of the dummy in the manner above described and then while the ends of the dummy are outwardly sprung as shown in Figure 1, the opposite ends of the plate and dummy are secured in the same manner. When the dummy ends are allowed to return to their'normal position, the printing plate will be held under tension in strict surface contact with the dummy.

In Figure 2, four dummy plates each carrying a printing plate as above described, are shown mounted on a plate cylinder I5. These dummies are locked in place by a central undercut ring l6 and clamps Il associated with the ends of the cylinder, all as well known to the industry.

I claim:

1. The method of mounting a sheet metal printing plate to a convex resilient dummy plate, comprising: outwardly flexing the ends of said dummy plate; overlaying the printing plate on the outer surface of the dummy plate; securing the ends of the printing plate to said dummy plate; and then permitting said dummy plate to spring back to its normal position,

2. A device of the character described, comprising: a resilient, arcuate mounting plate or dummy formed with a beveled tongue on at least one of its longitudinal edges and with a plurality of circumferentially spaced, longitudinally extending grooves on its inner surface; a lock strip formed with a longitudinal groove substantially conforming to the contour of said beveled tongue; and means for securing said strip over said tongue.

ARLINGTON W. STEPHENSON.

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