US991747A - Engraving or preparation of steel dies or rollers. - Google Patents

Description

J. T. RAWSTHORNE. ENGRAVING 0R PREPARATION 0 STEEL DIES 0R ROLLERS. APPLIOATIOK FILED OUT. 7, 1907.

991,747, Patented May 9, 1911.

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J'GSEPH TWEEDALE RAWSTHORNE, OF DINTING, ENGLAND.

ENGRAVING OR PREPARATION OF STEEL DIES 0R ROLLERS.

To all whom it may concern.-

Be it known that I, JOSEPH TWEEDALE RAwsTHoRNE, British subject, and resident of Dinting, county of Derby, England, have invented certain new and useful Improvements in the Engraving or Preparation of Steel Dies or Rollers, of which the following 15 a specification.

The invention relates to the engraving or preparation of the steel dies employed in the engraving of copper printing rollers such as used for calico printing or other metal cylinders or rollers in which the gradations of shade in the pattern are obtained from dots indentations or depressions in the surface of the roller.

Hitherto for the production of such style of shading the dies have chiefly been prepared by hand work and where pentagraph machines have been employed for the purpose the pattern has been prepared on a plate by punching thereon by hand the indented dots comprising the pattern.

The invention will be fully described by reference to the accompanying drawings.

Figure l. is a side elevation of die with a number of indents over its surface. Fig. 2.. is a section of same. Fig. 3 is an em bossed roller or mill A with points or pins projecting from its surface. Fig. 4C. is a sect-ion of same. Fig. 5. is an embossed pattern plate P.

In carrying out the invention I prepare a plate P which I term an embossed pattern plate over the entire surface of which are indented anumber of fine dots, indentations depressions or recesses 2. This plate is preferably zinc though it may be made of other metal or material capable of receiving and retaining such impressions. The indentations or depressions 39 upon the surface of the embossed pattern plate P are arranged geometrically to correspond with the indentations or depressions required to be produced upon the surface of the steel die but are arranged to a considerably greater scale, that is to say, that while the indentations on the plate may be as fine and small as possible their distance apart is say 2% to 10 times greater than those required on the steel die. Upon the embossed pattern plate after the indentations are made the outline p of the pattern is traced.

Indented pattern plates have been produced in several ways :-(a.) By setting out the position of each indentation geometri- Specification of Letters Patent.

Application filed October 7, 1907.

Patented May 9, 1911.

Serial No. 396,343.

'cally or otherwise and punching by hand.

(b.) By transferring from a paper or other pattern and then punching by hand. By photographing from a screen or pattern on to the plate and then etching the indentations thereon.

The method I at presentprefer to adopt after experimenting with all of the above methods is to prepare a steel mill or roller A having embossed over the surface a number of points or pins a corresponding to the indentations or depressions 77 required upon the embossed pattern plate P and then indenting the plate P over its whole surface by passing it between this embossed mill and another roller using suflicient pressure to emboss the pattern plate with the indentations. The embossed steel mill is prepared from a die B Fig. 1 with indentations Z) punched therein by hand. The mill A can be employed again and again to prepare any desired number of embossed pattern plates. The pattern plate so prepared with the indentations over its whole surface has then an outline of the pattern 39 traced over the indentations p. In use it is placed upon the table of a pentagraph engraving machine and the indentations thereon are reproduced in a proportionately reduced scale upon a steel die or metal cylinder by means of a punch such as described in the specification of Barrs Patent No. 824088 of 1906. The die or metal cylinder is mounted upon a carriage at the back of the machine under the punch.

The operator moves the pointer of the machine over the embossed pattern plate inserting it in each indentation or depression thereon within the traced pattern and then treadles or releases the punch which falls upon the die or cylinder making an indent therein. The punch is provided with an adjustable weight and it may be operated a second time. The die or cylinder is preferably punched first and the outline of the pattern engraved upon it afterward though the outline may be first engraved and the punching then be done. The steel die is employed in the ordinary way to form a mill from which the copper printing roller is embossed or engraved.

\Vhat I claim as my invention and desire to protect by Letters Patent is The process of preparing or producing an embossed pat-tern plate for use in a pentagraph machine for engraving steel dies employed in the preparation of copper printmy name in the presence of two subscribing ing rollers, consistmg 111 nnpresslng 1ne Witnesses. chanlcally over its entire surface a plurality of geometrically arranged dots and subse- JOSEPH TWEEDALE RAWSTHORNE' quently engraving the outlines of any pat- Witnesses: tern over and among such dots. J. OWDEN OBRIEN,

In wltness whereoi, I have hereunto slgned B. TATHAM \VOODHEAD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G.

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