Technikatörténeti szemle 7. (1973-74)

TANULMÁNYOK - Opitz László: Jedlik Ányos automatagépe

SUMMARY AUTOMATIC Dl WIDING MACHINE BY ÁNYOS JEDLIK The first physicist to design an optical grating capable to resolve a complex raz to its colors was Fraunhofer in Germany, who published his spectrum analysis observations in 1814 — 1815. Stimulated by his results, a number of research workers started to deal with this topic simultaneously. Norbert, another German physicist, produced highly appreciated gratings with his indexing machine druing the years after 1820. These machines, however, as well as (hose designed by other comtemporary experimenters could not maintain an e qual distance between the grate lines, nor the required extremely high precision of line number per mm because of their manual adjustment, in spite of the increased attention and patience exerted. A milestone in the development history of the, design of gratings was represented by the automatic indexing machine constructed by Anyos Jedlik Hungarian physicist in 1853, and made adaptable for electromotor drive two years later. This ingenious solution of continouos operation has made Jedlik's machine (Figures 1 and 2) outstanding among the contemporary constructions, inculding the earlier types as well. Operation control was made by a square iron frame of adjustable oscillation, attached to the rotating arm of the driving wharf (Fig. 3), by means of the pivot connected bars actuated under the table. The top pushbar of the frame reciprocated the iron prism holding the work; the second one lifted and lowered the diamond holder by means of an eccenter, while the third one ensured uniform line distribution and the proper feed of the scratcher diamond holder (Figures 4 — 6). The screw spindle moved the spiral casing of the needle holder (Fig. 7) according to its pitch and angular displacement. Minor seizures due to thread irregularities were compensated for by the Cardano suspension of the casing (Fig. 8). In the differential screw version, the difference between the two-way movements of a higher and a lower pitch screw, respectively, not too difficult to manufacture even at that time, moved the diamond holder, just like a small-pitch screw spindle which, however, was much more difficult to produce (Fig. 9). In the spiral grating version the glass to be lined (Fig. 10) was located on the circular work table instead of the reciprocating iron prism. The color effect of the gratings produced by the Jedlik machine was superior to that of any previous apparatus and was, therefore, sought for even abroad. The indexing machine designed by the American physicist Rowland in 1882 transferred indexing to a large radius concave reflecting surface and, thus, proved to be much better for spectrum photography than any of the former solutions. In 1948 Sir Thomas Merton transferred the fine pitch spiral line into a cylinder. His special process eliminated any eventual error, and the impression thus obtained has made the grating suitable for reproduction.