BACKGROUND OF INVENTION
The invention described herein relates to improvements to quartz analogue wristwatches that use disc hands and an illuminated dial for reading time in the dark. An electroluminescent sheet placed over the movement at the bottom of the discs serves as a backlight at the push of a button. This improvement over the previous inventions helps in reading time distinctly with the help of an electroluminescent sheet along with openings in the discs. Further, a greater visual impact is also created due to the rotating discs printed with different patterns / characters.
PRIOR ART
At present electroluminescent devices have been used in wristwatches as a lamp that serves as a backlight. This device does not by itself help in any way in keeping time.
The present method of time display in wristwatches used the electroluminescent sheets with traditional hand or pointers for display of time in the dark (US4775964 & US5764599).
The light given out by the electroluminescent sheet produces only a silhouette of the hands when seen in the dark.
Designs using circular discs in place of conventional hands to show time have been proposed earlier.
The US patent No 3934405 describes a mechanism where a rotating disc made from colorless plastic material with a reference mark is used in place of a normal second hand and with conventional type of hour and minute hands.
The US patent No 3803831 also describes a rotary indicator apparatus with graduated discs for effecting a unique visual effect.
The US patent no 4737941 describes an analogue type wristwatch with rotating circular films made of a plastic material and with an electrostatic shielding device.
The above three inventions under US patent No 3934405. 3803831 & 4737941 do not have any arrangement for backlight or illumination to read time in the dark.
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OBJECTIVES OF INVENTION
The main object of the invention is to provide an improved time display using discs instead of conventional hands or pointers coupled with the use of an electroluminescent sheet that serves as a source of illumination to read time in the dark. Another object of this invention is to provide a rugged mounting assembly for the discs by providing a sandwich type of mounting which allows for better control on the perpendicularity of the discs with respect to the fitting hole.
Another object of this invention relates to a quartz analogue watch with a display by means of thin circular discs. The hour disc is sandwiched between a lower bush and a washer. The lower bush has a hole that fits snugly on the hour wheel pipe, which rotates about an axis at one rotation every twelve hours. Similarly, the minute disc, sandwiched between a lower bush and washer, is fitted on the cannon pinion, which rotates about its axis at the rate of 1 rotation every one hour.
STATEMENT OF THE INVENTION
According to this invention, the hour and minute discs are provided with openings in them. Profiled openings in hour and minute discs allow light from the electroluminescent sheet placed at the bottom of the discs to pass through them creating an illuminated area. In the dark, these two patches of light act as the hour and minute references and helps in the reading of time.
BRIEF DESCRIPTION OF THE DRAWING
4.1) FIG. 1 shows cross-section showing position of EL sheet and disc hands in the final assembly of watch.
4.2) FIG. 2 shows Hour disc blank assembly of disc with bush.
4.3) FIG. 3 shows Minute disc blank assembly of disc with bush
4.4) FIG. 4 shows Hour disc blank
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4.5) FIG. 5 shows Minute disc blank
4.6) FIG. 6 shows hour bush
4.7) FIG. 7 shows minute bush
4.8) FIG. 8 shows different hour blank profile used.
4.9) FIG. 9 shows different minute blank profile used
4.10) FIG. 10 shows the method of illumination with EL dial glowing and Disc hands with EL.
DETAILED DESCRIPTION OF THE DRAWING
FIG.l shows cross section of a complete watch. An EL (electroluminescent) sheet (I) is fitted on the top surface of the movement (2) and is electrically connected through a PCB to a battery power source and a switch in the form of a push button (3) attached on the outer case. The EL sheet (1) is connected in such a manner that when the push button (3) is activated, it lights up thus creating an illuminated background. The hour disc (4) slides onto the hour bush (5) over which a washer (6) is placed. The open end of the bush over the washer (6) is then flared open with a tool so that the disc is secure between the hour bush (5) and the washer (6). The hour disc (4) fitted on the hour bush (5) is then fitted on the hour wheel pipe (7) through a frictional engagement such that when the hour wheel pipe (7) rotates, the hour bush (5) fitted with the Hour disc (4) also rotates.
Similarly, the minute disc (8) slides on the minute bush (9) over which a washer (10) is placed. The open end of the minute bush (9) over the washer (10) is then flared open with a tool so that the minute disc (8) is secure between the minute bush (9) and the washer (10). The minute disc (8) fitted on the minute bush (9) is then fitted on the cannon pinion (11) through a frictional engagement such that when the cannon pinion (11) rotates, the minute bush (9) fitted with the minute disc (8) also rotates.
The hour disc (4) fitted over the hour wheel pipe (7) and the minute disc (8) fitted over the cannon pinion (11) rotate independent of each other.
Markings in the form of hands are printed over the hour (4) and minute discs (8) which show time during the day. In the dark, when the push button (4) is activated, the EL sheet (1) glows and forms an illuminated background. Since the hour (4) and minute discs (8) carry openings in them, the light from the EL sheet (1) passes through them and shows illuminated profiles of the hour (4) and minute hands (5) thus allowing the wearer to read time in the dark.
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It is evident from the description of the mechanism above that the unique method of mounting the discs and the interplay of the patterns / profiles on minute (8) and hour discs (4) provides an enhanced visual effect.
The transparent dial (12) placed just above the EL sheet (1) allows the light to pass through. Back cover (13) is fit to the rear side of the case (15) and the mineral glass is fit to the top or front side of the case (18). The back cover gasket (14) and mineral glass gasket (16) ensures water resistance. The minute ring (17) placed above the transparent dial (12) enhances the aesthetics.
FIG. 2 shows hour disc blank assembly where the hour disc (1) slides onto the hour bush (3) over which a washer (2) is placed.
FIG. 3 shows the minute disc blank assembly where the minute disc (1) slides on the minute bush (3) over which a washer (4) is placed.
FIG. 4 shows hour disc blank where the hour disc (1) with the opening (3) is fitted with hour disc bush (2)
FIG. 5 shows minute disc blank where the minute disc (1) with the openings (3) is fitted with minute disc bush (2)
WE CLAIM
01) In a quartz analogue wristwatch having rotating discs with printed patterns /
profile openings cut out on them for hour and minute hands allow reading of time
during the day.
2) The quartz analog wristwatch as claimed in claim 1 allows reading of time in the dark on the push of a button activating an EL sheet thus creating illuminated light patches in the form of hour and minute hands.
3) The quartz analog wristwatch as claimed in claim 1 to 2 is provided with hour and minute discs sandwiched between a bush and washer thus providing a secure method of fitting the disc on the hour wheel pipe and cannon pinion.
4) The quartz analog wristwatch as claimed in claim 1 to 3 used aluminium material of horological grade allowing patterns to be printed on them and driven by a normal step motor used in a quartz watch.
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