US3164953A

US3164953A - Clock

Info

Publication number: US3164953A
Application number: US281693A
Authority: US
Inventors: Theodore A Granroth
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 1963-05-20
Filing date: 1963-05-20
Publication date: 1965-01-12
Anticipated expiration: 1982-01-12

Description

Jan. 12, 1965 T. A. GRANROTH 3,164,953

cLocx Filed May 20, 1965 INVENTOR United States Patent O assignor to Ill., a corporation This invention relates to clocks, and more particularly to an improved clock having provision for illumination of the face thereof. Y

It becomes desirable in certain types ot clocks, such as are used in sleeping rooms (eg. alarm clocks and clock radios), to provide some means for rendering the clock suliiciently visible in a darkened environment to enable an observer to tell the correct time.. One method of doing this is to coat the hands and the numbers of the clock with phosphorescent chemicals. rthis is unsatisfactory in certain respects because, during along period of darkness, such chemicals may lose much of their stored energy, decreasing the brightness of the hands and numbers. Another approach to the problem is to coat the hands and numbers with radioactive material. Because of the radiation associated with such chemicals, however, the general public is often hesitant to purchase such a device. Another possibility is to light the clock face itself by means of an electric light. In general, however, such lights utilize too much power to be operated continuously, especially when the whole face is to be lighted. Consequently, an on-olt switch must be provided with the attendant inconvenience and increased cost to the consumer.

Accordingly, it is an object of this invention to provide improved, non-chemical lighting for the face of a clock.

Another object of the invention is to provide a clock having an evenly lighted face visible in a darkened environment and apparently unlighted when viewed in a lighted environment.

Still another object of the invention is to provide a clock having a continuously electric lighted face and utilizing a minimum amount of current.

A feature of the invention is theprovision, in a clock, of a translucent face and a disk shaped light conductor having a frosted surface and being mounted behind the face with a neon bulb mounted on the edge of the light conductor and lighting ythe light conductor to silhouette the hands of the clock.

Another feature of the invention is the provision of a light conductor constructed of frosted Plexiglas, and the further provision of an unfrosted portion on the light conductor near the light source for even distribution of light. The available light can be increased by utilizing a reflector behind :the light conductor, which reflector has a non-rellecting portion behind the unfrosted portion of the light conductor for even disrtibution ot light.

Still another feature of the invention is the provision of a translucent clock face with a reversed second face printed on the back side of the clock face and having opaque figures. A light conductor is provided behind the secondface and silhouettes the hands and the figures of the second face at night.

In the drawings:

FIG. 1 is a perspective view of a clock radio incorporating the invention;

FIG. 2 is a view of :the appearance of the clock shown in FlG. 1 when viewed in a darkened environment;

FIG. 3 is an exploded view of the clock shown in FIG. 1;

FIG. 4 is a perspective view of a clock radio incorporating a second embodiment of the invention; and

Patented Jan. 12, 1`95 FIG. 5 is an exploded View of the clock shown in FIG. 4.

In accordance with the invention, a clock is provided with a translucent face disposed behind the indicator hands thereof. A substantially disk shaped frosted Plexiglas light conductor is mounted behind the translucent portion of the clock face. This light conductor has a portion extending from the periphery thereof which portion has a mounting recess in which is disposed a neon bulb. The neon bulb may be connected across the line and in series with a resistor to draw a very small amount of current. When the bulb lights, the light conductor transmits light over the rear of the clock face silhouetting the hands of the clock.

One embodiment of the invention utilizes a second clock face painted on the rear side of `the translucent clock face, which second clocl: face is silhouetted by the light conductor. Another embodiment of the invention utilizes an opaque ring containing transparent figures which are lighted by the light conductor. Both embodiments of Ithe invention utilize a light conductor of frosted Plexiglas and having an unfrosted section adjacent the neon bulb to permit an even distribution of light across the clock face. When the clock face is viewed in a lighted environment, the light produced by the neon bulb is insuicient to oil-set the effect of the rellected environmental light from the translucent clock face. Accordingly, the silhouetting elect does not take place until the environment becomes darkened suiciently for silhouetting to occur.

Referring now to FIG. l, there is shown a clock radio 11 having a control panel 13 with appropriate controls thereon and further having a clock mounted therein. The clock includes a second hand 15, a minute hand 17, an hour hand 19 and an alarm setting indicator 21. The clock also includes appropriate iigures 23 imprinted about the face 25 in the usual manner.

Face 25 contains a translucent portion 27, which may be translucent vinyl, or vacuum metalized butyrate. Metalizied butyrate presents a metallic appearance when viewed in a lighted environment but is translucent and will transmit light which will be visible to an observer when reflected light becomes low enough.

Referring now to FlGS. 2 and 3, a frosted Plexiglas light conductor is mounted behind face 25. Conductor 29 has a pair of openings 3l formed therein to permit passage of the alarm and clock setting controls therethrough. In addition, a central opening 33 is provided for the drive` post of the hands. Light conductor 29 is substantially disk shaped and has an extension 35 at the periphery thereof. Extension 35 includes a recess 37 in which a neon bulb 39 is mounted. Bulb 39 may be lighted by connection in series with a resistor across the line source. The area 41 adjacent extension 35 is unfrosted to permit a more even diffusion of the light throughout conductor 29, and avoid a concentration of light adjacent light bulb 39. A shield 43 of opaque material such as aluminum foil surrounds extension 37 to permit lighting only through light conductor 29.

Y With the components in place and when viewed in a darkened environment, light conductor 29 will cause translucent section 27 to glow with a soft light, silhouetting the hands l5, 17, l and 2l. In addition a series ot` opaque figures 45 are disposed on the reverse side ot translucent section 27. Figures 45 comprise a smaller second clock face which is silhouetted when the glow from light conductor 2'9 is visible through translucent portion Z7. When viewed from a lightened environment, only the larger exterior clock face will be visible. FlG. 2 shows the appearance oi ythe second cloclr face and the silhouetted hands as viewed from a darkened environment.

Vface to silhouette said Conductor 29 permits the use of neon bulb 3i? which may be a very low light source. Nevertheless, the efficient dissemination of light behind the clock face 25 permits bulb 39 to provide a soft glow over the entire face when viewed rom a darkened environment. In addition, because a small neon bulb 39 may be used, low current drain takes place. This permits the bulb to be kept on at all times, `eliminating the need for a switch. Relpacement will seldom, if even-be needed because such neon bulbs are of very long lite. Clock hands l', i7, l1) and 21 may of course, be driven by a motor assembly 47. A glass cover-fl@ protects the clock face and hands.

Referring now to FlG-S. 4 and 5, a Vsecond embodiment of the invention is shown. in the clock radio Sti, of FlGS. 4 and 5, the clock. face is comprised of a translucent section 5l and a ring S3 of opaque vinyl containhands l5, i7, ligand 2l will be silhouetted gainst trans? lucent portion Sl, and numbersl 55 will pass light reflected Yfrom reiiector S7 so that the numbers are visible in the dark. Here again, when tl e environmental light is suiiicientlyfstrong, the ellect of neon bulb 39 will be unnoticeable. K i i It may therefore be seen that the invention provides a cloclt wherein improved non-chemical lighting is provided. The-face ot the clocl': is evenly lighted in a darliened environment and apparently unlighted in a lighted environmenhwhereas in reality continuous lighting exists with minimum current drain,

l claim:

1. A clockrliaving provision for illumination of the face thereof, Vincluding in combination, a plurality of opaque indicator hands, a clock face disposed behind said indicator hands-and including a translucent portion adapted to silhouette said hands when lighted, a substantially disk shaped light conductor having a frosted surface and being mounted behind saidtranslucent portion ot said clock face, a bulb retaining extension on the periphery of said light conductor, a neon bulb secured in said bulb retaining extension and supplyingrlight to said iight con-V ductor'ior lighting said translucent portion of said clock handasaid frosted surface of said light conductor having an unfrosted portion adjacent said bulb to even the intensity otvtiiellivht over tbe entire light conductor, Vwhereby the position of said hands is observable from a darkened environment. A

- 2. A clock having provision for illumination of the face thereof, including in combination, apluralityV of opaque `indicator hands, a clock face disposed behind'V said indicator hands and having a first set of clock figures f thereon visible in a lighted environment, saidclock face further having a translucent Vpoi on inwardly Vof said first et of clock igure's adapted to s houette said hands when lighted, said translucent portion including an opanueV second set of clockV ligures on the reverse side thereoiC to Vbe silhouetted when said translucent portion is lighted, a

substantially shaped light conductor having a frosted said bulb retaining extension and supplying light to said light conductor for lighting said translucentrpoi'tion of said clock face to silhouette said hands and said second l set of figures, said frosted surface of said light conductor havinfy an unfrosted portion adjacent said bulb to permit even distribution of light throughout said livhtconductor, whereby' the position of said hands and said second set or" clocl; figures is ob ervable from a darkened environment, said neon bulb being of a value to render said translucent portion substantially opaque in a lighted environment. i

3. `l'n a radio receiver, a clock having provision for illumination of the face thereof including in combination, a plurality or" opaque indicator hands, a clock face disposed beliind said indicator hands, said clock face having a vacuum metalized translucent portion in the center thereof adapted to silhouette said hands when lighted, said translucent portion including opaque clock gures painted on the reverse side thereof to be silhouetted when said translucent portion is lighted, a'substantially disk shaped light conductor having a frosted Vsuriace and being mounted behind said translucent portion of said clock face, a bulb retaining extension on the periphery of said light conductor and integral therewith, a neon bulb secured in said bulb retaining extension and supplying light to said light conductorfor lighting said translucent portion of said clock tace to silhouette said hands and said ligures, light shield means surrounding said extension and permitting emission of light only through said light conductor, said frosted surtace ot said light conductor having an unfrosted portion adjacent said bulb to perinitireven distribution of light throughout said light conductor, whereby the position of said hands and said cloclc figures is observable from a darkened environment, said neon bulb being of a value to render said translucent portion substantially opaque in a lighted environment.

4. A clock havingrprovision for illumination of the face thereof, including in combination, a plurality of opaque indicator hands, a clocii face disposed behind said indicatorhands, said cloclt face having a substantially circular translucent portion in they center thereof adapted to silhouette said hands when lighted, and further having an opaque annular band surrounding said translucent portion and havingtransparent' clock ligures thereon, a substantially disl; shaped light conductor having a frosted surface and ybeing mounted behind said clock face, a bulb retaining extension on the periphery of said light conductor, a neon bulb secured in said bulb retaining exterision and supplying light to said light conductor for lighting said translucent portion of the said cloclr face to silhouette said hands and illuminate said figures, said frosted surface of said light conductor having an unfrosted portionV adjacent said bulb to perrnit even distribution of light throughout said light conductor, light shield means surrounding said extension and permitting emission of light portion substantially opaque in a lighted environment.

References Cited by the Examiner v UNiTEl) STATES lATENTS ,680,813

l LEYANDV-M. MARTIN, Primary Examiner.

i. P. srizait, Examiner.

d neon kbulb beinU of a value to render said translucentv

Claims

1. A CLOCK HAVING PROVISION FOR ILLUMINATION OF THE FACE THEREOF, INCLUDING IN COMBINATION, A PLURALITY OF OPAQUE INDICATOR HANDS, A CLOCK FACE DISPOSED BEHIND SAID INDICATOR HANDS AND INCLUDING A TRANSLUCENT PORTION ADAPTED TO SILHOUETTE SAID HAND WHEN LIGHTED, A SUBSTANTIALLY DISK SHAPED LIGHT CONDUCTOR HAVING A FROSTED SURFACE AND BEING MOUNTED BEHIND SAID TRANSLUCENT PORTION OF SAID CLOCK FACE, A BULB RETAINING EXTENSION ON THE PERIPHERY OF SAID LIGHT CONDUCTOR, A NEON BULB SECURED IN SAID BULB RETAINING EXTENSION AND SUPPLYING LIGHT TO SAID LIGHT CONDUCTOR FOR LIGHTING SAID TRANSLUCENT PORTION OF SAID CLOCK FACE FOR LIGHTING SAID TRANSLUCENT PORTION OF SAID CLOCK LIGHT CONDUCTOR HAVING AN UNFROSTED PORTION ADJACENT SAID BULB TO EVEN THE INTENSITY OF THE LIGHT OVER THE ENTIRE LIGHT CONDUCTOR, WHEREBY THE POSITION OF SAID HANDS IS OBSERVABLE FROM A DARKENED ENVIRONMENT.