US1607822A

US1607822A - Method of producing luminous dials for clocks and watches

Info

Publication number: US1607822A
Application number: US101656A
Authority: US
Inventors: Charles H Granger
Original assignee: WATERBURY CLOCK CO
Current assignee: WATERBURY CLOCK CO
Priority date: 1926-04-13
Filing date: 1926-04-13
Publication date: 1926-11-23
Anticipated expiration: 1943-11-23

Description

Nov. 23 1926. 1,607,822

' c. H. GRANGER METHOD OF PRODUCING LUMINOUS DIALS FOR'CLOCKS AND WATCHES Filed'April 13, 1926 Patented Nov. 23, 1926.

'U'Nl'T E STAT ES JATENT arr-cs.

CHAR-LES H. GRANGER, OF WATERBUB' Y, CGNNECTIGUT, ASSIGNOR T0 \VATER-BURY CLOCK 00., OF WATER-BURY, CONNECTICUT, A CORPORATION.

METHOD OF PRODUCING LTJMINOUS DIALEi FOR CLOCKS AND WATCHES.

Application filed April 13, 1926. Serial No. 101,856.

This invention relates to improvement in method of producing luminous dials for clocks and watches. Heretofore, luminous dials, so-called, for clocks and watches have generally been laboriously produced by the manual application with a fine brush of a paint containing a modicum of radioactive material to dial-numerals previously printed upon the dials in the usual manner with ink or some substitute therefor. his method of applying a modicum of radioactive material to dial-numerals is excessively delicate and laborious, and such is the apprehension regarding the character of the material in its effect upon the health of the workers that great difficulty has been found in securing girls, by whom such work is done, to carry it on. The method above described is also objectionable on account of the expense, the impossibility of securing a film of uniform thickness upon the numerals, as well as producing numerals of sharp definition or clear-cut edges. The object of my invention is to not only overcome the objections above recited, but also to produce luminous clock and watch dials of superior appearance and effectiveness, due to the application of the material in relief with uniformity of thickness and sharpness of outline.

With these ends in view, my invention consists in a method of producing luminous dials for clocks and watches consisting in cutting dial-numerals in intaglio in a suitable die, then filling the intaglio numerals so out with a composition radioactive luminous material combined with an adhesive carrierand then transferring the said material under pressure to the flat surface of a clock or watch dial.

In the accompanying drawings:

Fig. 1 is a view in elevation of a watchdial produced by following my improved method;

Fig. 2 is an enlarged broken sectional view thereof on the line 2-2 of Fig. 1;

Fig. 3 is a plan view of the die employed and V 1 Fig. 4 is an enlarged broken view thereof on the line 4-4 of Fig. 3.

In carrying out my invention, a metal die 5 of suitable size is carefully engraved in intaglio with dial-numerals 6 of suitable design and size for the particular character of clock or watch dial to be produced. The intaglio dial-numerals of such a diev are then filled with what, for want of a better word, I may calla luminous ink, composed of radioactive material in the form of fine crystals, such material being combined with an adhesive carrier, which may be similar to printers ink base. The die is now wiped as in printing, and the remaining luminous ink in the dial-numerals transferred, under pressure, in a suitable printing press, to the flat face of the clock or watch dial 7 to be produced, which, consequently, has imposed upon it, in clear-cut relief, corresponding to the depth of the intaglio dialnumerals cut in the die, a series of sharplydefined luminous dial-numerals 8 of uniform thickness, and much sharper in outline than any dial-numerals painted by hand with a brush can be. Moreover, the luminous material when applied in this manner in clearcut relief, is more condensed and effective than when manually applied by means of a delicate brush, for the reason that whereas the material, when applied with a brush, presents only a flat surface for supplying illumination, its edges being negligible, imposed numerals applied under my improved method present bold edges as well top surfaces for supplying illumination.

By this method, the objection raised by the girls, who heretofore have done such work, to the supposed danger to health from handling radioactive material, to which considerable' avoided.

I am aware that it has been proposed to print clock-dials by the so-called offset process of printing, which consists in first printing upon an intermediate sheet of flexible material and then transferring the ink applied thereto to the ultimate surface to be printed. However, the so-called offset process of printing is not available for the imposition upon a dial of luminous dial-numerals in marked relief with clearly defined. edges, such as it is the object of my invention to produce.

I claim:

A method of producing luminous dials mystery attaches, is entirely ,for clocks and watches consisting in cutting dial-numerals in intaglio in a suitable die, then filling the intaglio numerals so cut with a composition of radioactive luminous I material combined with an adhesive carrier,

and then transferring the said material under pressure dlrectly to the flat surface of a CHARLES H. GRANGER.