US1773768A - Printing plate - Google Patents

Description

Aug. 26, 1930. H. A. w. WOOD PRINTING PLATE Filed Nov. 4. 1926 Patented u 26,1930

HENRY Al WISE woon, or new Yonx, v. Y., lissronon "r woon NEwsPArEnMA- vCI-IINERY CORPORATION, ornnwxonm n; 31., A COEPOBATIONOF VIRGINIA I lnrirrrivernnrn Original application filed June Serial 721,272.. Divided and this application "med November This application assessor my application, Serial No. 7 21,27 2, filed June 20, 1924 on a method of casting printing plates without a riser.

The principal objects of the present invention are to provide an improved printing plate having a length less than the length of the matrix from which it is castwith a surface along the edge through which the metal is cast in producing the plate which does not need any finishing after it is cast.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings in which f r Fig. l is an end view of a printing plate constructed in accordance with this invention; and V Fig. 2 is a sectional view of a part of the mold in which the plate can be cast showing the edge of the plate as produced therein.

This plate is shown in the drawings as a curved semicylindical plate for use on rotary printing presses, although the invention can be'used for plates for other other shapes. a

The conventional method of casting plates for rotary printing presses is to pour molten metal into a mold, in which a matrix has been placed. This mold is generally closed on all 7 sides and edges exceptsthe edge through which the metal is poured. On this edge a riser is formed, whichserves the purpose of a feeder, from "which the shrinkage within the plate during the cooling processis supplied. This riser is generally so proportioned that itremains'in a molten state while the plate is solidifying, so that a reservoir of molten metal is being maintained during that process. 7 a

From'this it will be seen that it eventually becomes necessary to rid the cast plate of this riser, so that the plate may be produced with a straight finished edge instead of the irregularly shaped mass,'formed thereon by the 4, 1326. serial" n6. 146,274.

purposes and of riser?" This makes .it necessary tof'provide a device for severing the riser from the plate proper, usually in the shape of acutting mechanism of; one formor another, accord ing to the idea of :the designer and the-demands of the machine. The process 'of'cutfting'oif the riser after it has solidified pro- 'cluces a quantity of chips orjsawdust which are apt to clog theworkingparts'ofthemachineandin'terfe're with its op ration, It also serves to slowdown the production of plates, since a certain number ofse condsfis required for theact of cutting ofithe' riser. 1 It has been suggested that the riser while it still is in the molten state, can be cutoif'loy means of a' rotatingvalve or the like. r This method-"has proved defective,' however,"be-

cause among other objections, no way has been found of cutting off the molten riser of a printing plate close enough to the edgeof the isype" matter to avoid reducing the number of i This has been because the valve device's proposed have never been able to sever the molten riser at a point nearer to the type than, 1 the edge of the matrix clip, which is usedto' secure thematrixvin the mold. Thus, a'b'lank space has had to beileft on the plate edgeequa-l in'widthto the clamping edge or thematrix by as'many lines of t'y'peiat least'as the clamp ing edge of the matrixis wide. :EAsithe fshortening' of the" printing'surface of a newspaper plate, inthe direction-of its curvature,.reduces the numberof type lines the page may carry, andas'advertis'ing is sold by the line, it has been necessary -tobring the-type area of; a; page to the uttermost edge of the printing plate. It "is this limitation that has largely made impracticable the otherwise desirable method of cutting ofi the riser whilein its molten state. 7 r Theprinting plate P in its-completed state is producedina mold and cast in the method setforthin the above identified application without any subsequent finishing. That-is,

this' surface 10 is merged into aisl an tinglsurion which shortens the type surface of theplate 59 face 11 which extends to the rear concave surface 12 of the plate. The usual ribs 39 are shown and a projection 43 is produced due to a recess in the surface of the cylindrical core on which the plate is cast. This projection and'reeess are used as a means of holding the plate positively in one position on the core as the latter rotates to the point atwhili the plate is taken off. The opposite edge 14 of the pl ate'lias a flat edge cast in theusual way. l N

This plate is cast in a mold such as shown and describedin my above mentioned application which involves a casting box 22, core 25, matrix bars 23 and clips 24. These clips hold thematrix just beyond ,tlie bolster B.

Themetalis-introduced through a spout 19 from the melting pot 6' and flows against the core 25;When the mold is fully closed as shown inFig. 2 a shutter or valve 29 is forced in circumferentially up to the position in the mold cavity shown in Fig. 2. While the metal is in a plasticsta te, this forms the edge e f-the plate as shown in-Fig.'2, with the help of the "matrix clips. This forms a surface finishedin the act of casting atthat point so that the plate is ready to go on the press as it I an inwardly slanting surface extending to the concave surface of the plate.

"Intesti n'ony whereof I have'hereunto affixed my signature.

- Y HENRY A. WISE WOOD.

comesefrom the, mold without finishing at this point.

Of course the printing plate P is provided on; its innerconcave face with finishing ribs p which are cast in suitable grooves39 in the core for that purpose; On account of the proximity of the adjacent group of grooves 39 around the cylinder, I find it advisable to provide a lip 40 at the lower end of the shutter 29. This projects downwardly to, preventt the metal from running upwardly to the upperhalf of thecore when theshutter i 29 is partially retracted It will be seen that the riser edge of the plate is cast against thesurf'ace of thegparts Mand 29. These parts are finished to the proper shape to form the desired configura- 5 jtion' of this edge of the plate in the casting p operation: Thus the plate can be" clamped properly on the cylinder of the press by the J;

usualqclam'ps without any finishingof this edge after it leaves the mold. The ribs p may or may not be shaved along their concave surfaces; beforebeing clamped to the cylinder. Althoughthereis no riser the advan tages o-fthe riser are not lost because the metal isforcedintd the mold solidly as it is cast.

' Fiirthermore,-notwithstanding that the metal supply is separated from the caster plate while the metal isrin a fluid condition the plate is'ofnogre'ater length than: a similar plate from which the riser has been sawed after loooling, Neitheni-s any blank space necessary the plate conforming to the Widthjof the clamping edge *of the matrix. Thus/the type surfaceof the plate does not have to be shortened. N

. w =Al-thoughiL-halve illustrated and described IUD

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