US2948327A - Apparatus for formation of composite printing plates - Google Patents

Description

E. J. HORNER Aug. 9, 1960 APPARATUS FOR FORMATION OF COMPOSITE PRINTING PLATES Filed June 20, 1957 H. a a 2 u m H Q .i \\\\N\\\ NE 2 I G &.

V 2,948,3i7 APPARATUS FOR FORMATION of coMroSrrE PRINTING PLATES Ellwood J. Horner, Armonk, N.Y., assignor to R. Hoe & Co., Inc., New York, N.Y., a corporation of New York Filed June 20, 1957, Ser. No. 666,886

3 Claims. (Cl. 154-- 1) This invention relates to the formation of printing plates, and more particularly to the bending of flat plates to produce curved printing plates therefrom, and to the formation of composite plates of this type.

The general purpose of the invention is to provide an improved plate bending and bonding mechanism for forming a composite plate in which the back may be of flexible metal having high tensile strength, such, for example, as stainless steel or aluminum alloy, and a printing surface of magnesium, zinc or other suitable metal having desirable properties from the etching and printing standpoints.

A plate forming mechanism embodying the invention in a preferred form will now be described with reference to the accompanying drawing and the features forming the invention will then be pointed out in the appended claims.

In the drawing:

Fig. 1 is an elevation view of the plate bending mechanism, with parts broken away;

Fig. 2 is a section on the line 22 of Fig. 1;

Fig. 3 is an enlarged section on the line 33 of Fig. 2;

Fig. 4 is an enlarged section view of parts shown in Fig. 2; and

Fig. 5 is an enlarged view of a portion of Fig. 1.

The machine utilizes a hydraulic cylinder, 10, containing a ram or piston 11, which supports a semi-cylindrical saddle 12 around which the plate is bent. A pump 13 and reservoir 14 serve, through appropriate piping 15,

to supply hydraulic fluid to the cylinder for accomplishing the cycle of operations as described below. The saddle 12 is maintained in alignment by means of guide rods 16 attached to the saddle and passing through bores in bracket element 17 affixed to the cylinder 10.

Side frames 20 serve to support the machine elements in operating position with reference to the saddle 12, in the following manner. Each frame 20 has guide ways 21 and 22 which receive rollers 23 carried on shafts 24 at the hands of rods 25, between which a draw sheet 26, typically of stainless steel, is secured by clamping screws 25' as shown in Fig. 3.

The inner wall of the guide ways 21, 22 is slotted as indicated at 27 in Fig. 5 to form slide ways 18 between which blocks 19 are fitted to slide, and stops 19' are provided to limit the outward motion of the blocks. These blocks have slots 27 (Figs. 4 and 5), in which the ends of the shafts 24 rest. Each slot extends from the center to the outer edge of the block and permits removal of the shaft 24 carrying the draw sheet 26. A boss 29 is formed on each of these blocks 19 to receive a loop formed on one end of a guide cable 30, that is secured thereto by .a screw 28. The guide cables 30, of which there are two at each side of the machine, pass around guide pulleys 31 within the frames 20 and are maintainedunder tension by springs 32. Cables 30 thus tend to hold rods 25 in the position of Fig. 1, stretching the draw sheet 26 flat across and directly above the saddle 12.

nited States Patent 6 In operation, the shaft 24 which is carriedin guide ways 21 is slipped out of the blocks 19 (the other shaft 24 moving along its guide ways 22 to permit this) and the shaft 24 having rollers in guide ways 21 is slipped out of the slots 27 in the blocks 19, .disconnectmg it from the cable 30 (which is fairly slack in this position) so that the draw sheet 26 may be thrown back '(to the left in Fig. 1), providing access to the saddle 12 for placing the plate components thereon. A precurved backing plate 40, is first placed in position, and the printing surface plate component 41 is then placed over it, as indicated in Fig. 1, and they are registered thereon with respect to each other in any convenient way, as by means of pins 42. A bonding layer 43 (Fig. 3) may be interposed between the plate components 40 and 41. The saddle 12 is provided with electric heating elements 45, for the purpose of facilitating the bending of the plate components, and also for applying heat as required in the bonding operation.

With the plate components in the position of Fig. l, the draw sheet 26 is drawn over them and its shaft 24 is slipped into the slots 27 in blocks 19. The hydraulic ram 11 is then actuated to raise the saddle 12 to the broken line position of Fig. 1.

The ends of draw sheet 26 are constrained by rollers 23 in the grooves 21 and 22 which slant upwardly and toward each other, as indicated, thus bending and tensioning the draw sheet 26 and also bending the printing plate component 41 into conformity with the backing plate 40, as indicated in Fig. 3. Sufiicient heat is supplied by the heating elements 45 to render the printing plate component bendable and also to soften or melt a bonding layer 43, if a thermoplastic layer is used, or to set this layer if a thermosetting bonding layer is used.

The invention is not restricted to particular metals or bonding materials, or to the precise order of operations involved in the preparation of the printing surface. For example, the printing surface layer 41 may be any of a variety of metals, such as magnesium, zinc, copper, etc., or of rubber, nylon or other plastics, and the printing surface may be prepared either before or after bending,

as by acid etching, engraving by electronic means, or various other types of formation; for relief, planographic or intaglio printing surfaces. The backing layer 40 may similarly be of any suitable metal or plastic, and typically may be of stainless steel or any of a variety of aluminum alloys. The bonding layer 43- may be applied as a sheet or film as shown, or it may be applied as a coating to either element, and may take any suitable form.

After the plate is formed and sufficient time has been allowed for any thermosetting action, the hydraulic ram and saddle are dropped back to the position of Fig. 1, the draw sheet 26 is thrown back from the plate and the formed plate is removed, restoring the parts to condition for another operating cycle.

What is claimed is:

1. Plate bending mechanism comprising, in combination, a saddle having control means for holding a flat plate while leaving the plate edges free to bend around the saddle, hydraulic mechanism supporting the saddle and moving it vertically, a draw sheet for wrapping the plate on the saddle to bend the same, and means holding and guiding the edges of the draw sheet, whereby the draw sheet is substantially flat and horizontal when the saddle is in a lower position and is wrapped around conforming to the saddle when the saddle is in an upper position, in which the means holding and guiding the edges of the draw sheet comprises bars along the edges of the sheet, rollers carried at the ends of the bars, and guide tracks receiving the rollers extending diagonally upward and inwardly toward each other, whereby as the central part of the draw sheet is moved upwardly, the

References Cited in the file of this patent UNITED STATES PATENTS Brautigarn July 5, Salzmann June 17, Oettinger Aug. 8, Faeber et a1 Aug. 17, Faeber et a1. Aug. 31, Green Oct. 26,

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