Indicia display unit

Abstract

An indicia display unit comprises an inner wheel bearing a number of indicia, the number being represented by an integer X, and an outer wheel bearing a number of indicia equal to nX where n is an integer. The outer wheel is also formed with a display window. The inner wheel is nestingly fitted within the outer wheel, and its indicia position is aligned with an indicia position on the outer wheel. The inner wheel is adapted to be driven for one cycle which includes (n + 1) revolutions. During the initial n revolutions of the inner wheel, the outer wheel is concurrently driven for rotation therewith to present successive indicias thereon for display. On the (n + 1)-th revolution of the inner wheel, the window in the outer wheel is interrupted to permit the display of successive indicia on the inner wheel by allowing the rotation of the latter alone.

Description

BACKGROUND OF THE INVENTION

The invention relates to an indicia display unit for displaying numerals and/or characters such as are used to represent the time of day or a day of the week in a digital clock or similar alphanumerical representations in an instrument or meter, and more particularly to such unit employing wheels.

A combination of an inner and na outer wheel interfitting with each other and each bearing indicia thereon permits an increased number of indicia to be displayed or an increased size of each individual indicia to be chosen for ease of viewing while maintaining the same space requirement, as compared with the use of a single indicia-bearing wheel. However, a conventional display unit of the kind described tends to be unreliable in operation because of complicated control means required to control the rotation of the wheels as a result of alternately operating them. In addition, such a conventional unit used inner and outer wheels of nearly the same diameters, which resulted in difficulties of the drive and also failed to provide more than twice the number of indicia on a single wheel.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an indicia display unit capable of providing a display of indicia on both the inner and outer wheels in a smooth manner for all the increased number of indicia by simplifying the control of rotation of the outer wheel through the provision of a display window in the outer wheel to permit a display of indicia on the inner wheel therethrough and through operatively connecting the outer wheel with the normally rotating inner wheel to allow a display of indicia on the outer wheel which corresponds in number to an integral multiple of the number of indicia on the inner wheel.

According to the invention, the inner wheel is maintained normally rotating, which facilitates the synchronization of the outer wheel therewith to initiate the engagement or disengagement therebetween. This also allows the number of indicia located on the inner and outer wheels, respectively, to be increased. Throughout the description, the term "indicia" is intended to include a numeral, a letter, a character or any other symbol.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of an embodiment of the indicia display unit according to the invention;

FIG. 2 is a perspective view of the unit shown in FIG. 1;

FIG. 3 is an exploded perspective view of the inner and outer wheels and their associated elements used in the indicia display unit of the invention;

FIGS. 4 and 5 are schematic views illustrating the arrangement according to the invention;

FIG. 6 is a developed view of a transparent sheet bearing indicias;

FIG. 7 is an elevational view of the outer wheel; and

FIG. 8 is a perspective view of part of the inner wheel.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Referring to the drawings, and specifically FIGS. 1 and 2, there is shown a clock 1 with a digital display incorporating the invention, the display being adapted to indicate from 0 to 24 hours. The clock 1 includes, in a juxtaposed and aligned array fromm the right to the left as viewed in these Figures, a unit's digit minute display wheel 2, a ten's digit minute display wheel 3, and a 24 hour display wheel 6 which comprises an inner wheel 4 housed within an outer wheel 5. A housing, not shown, is provided with a window 7 on its front side through which the time of day such as 12 hours 00 minutes may be displayed as shown.

Each of the wheels 2, 3, 4 and 5 is rotatably mounted on a shaft 12 which is mounted on and extends between a pair of side plates 10 and 11, the latter being connected together by stays 8 and 9. The unit's digit minute wheel 2 carries numeral representations from 0 to 9 along its peripheral surface, and has a gear 13 secured to one of its end faces. A motor 14 is mounted on the outer side of the side plate 10, and has an output shaft 15 on which is fixedly mounted a "second" feed wheel 16 having a pawl 16a, which intermittently engages and drives the gear 13 for rotation. The wheel 16 completes one revolution per minute, and each time the gear 13 is driven by the wheel 16, the wheel 2 is rotated through an angle which corresponds to the length of its periphery occupied by one numeral thereon.

A carry transmission 2a is interposed between the unit's digit and ten's digit minute wheels 2 and 3 to cause a rotation of the wheel 3 by an amount to displace one numeral position thereon each time the wheel 2 completes one revolution, or every 10 minutes. The wheel 3 carries two sets of numeral representations 0 to 5, arranged in tandem. For each one-half revolution of the wheel 3, or every 1 hour, the 24 hour display wheel 6 is rotated to displace one numeral position thereon through another carry transmission 17 to be described later.

The clock 1 includes an outer frame 18, on the inner wall of which is mounted a timer display wheel 19a, and a disc 19b is located opposite thereto for the operation of the timer. The timer includes a knob 20 for setting the display wheel 19a to a desired position, and another knob 21 coaxial with the knob 20 and provided for the purpose of time adjustment.

Referring to FIG. 3, the inner wheel 4 is shown carrying numeral representations of 1 to 12 at regular intervals on its periphery, and is integrally formed with a plurality of teeth 22 having a short height and a pair of teeth 23a, 23b (see FIGS. 4 and 8) having a greater height at its righthand end, as viewed in FIG. 4. A recess 4a is formed between the teeth 23a and 23b.

The outer wheel 5 carries numeral representations of 13 to 23 and 0 on its periphery and is also formed with a window 5a which serves for displaying the indicia on the inner wheel therethrough. The numeral representations on the outer wheel 3 and the window 5a are spaced apart at regular intervals. On the left-hand end face of the outer wheel 5, as viewed in FIG. 3, a gear 25 having a plurality of teeth 24 and a hiatus 25a is concentrically mounted with the outer wheel.

A toothed wheel 26 constituting the carry transmission 17 meshes with the teeth 22 on the inner wheel 4 and acts to rotate the latter through an angle corresponding to one numeral position thereon as the ten's digit minute wheel 3 completes one-half revolution. The toothed wheel 26 is fixedly mounted on a suitably journaled shaft 27 on which is also fixedly mounted another gear 28 which in turn meshes with the teeth 24 on the outer wheel 5. Further referring to FIG. 3, a toothed wheel 29 is located adjacent and opposite to the periphery of the inner wheel 4 and is adapted to be engaged by the pair of teeth 23a and 23b thereof having a greater height so as to experience one-fourth revolution during each complete rovolution of the inner wheel 4. The toothed wheel 29 is fixedly mounted on a suitably journaled shaft 30 on which is also fixedly mounted a toothed wheel 31, and the arrangement is such that the toothed wheel 31 alternately locks or frees the teeth 24 of the gear 25 on successive one-fourth revolutions of the toothed wheel 29.

As mentioned previously, the toothed wheel 26 meshes with the teeth 22 on the inner wheel 4, and comprises teeth 26a adapted to be driven by tall teeth 3a (see FIG. 2) integrally formed on one end face of the ten's digit minute wheel 3, and teeth 26b which normally abut against a locking disc 3b disposed on the shoulder of the ten's digit minute wheel 3 to be locked thereby, but which are adapted to enter a recess 3c in the locking disc 3b to permit a rotation of the toothed wheel 26 as the teeth 26a are driven by the tall teeth on the ten's digit minute wheel 3.

Similarly, the toothed wheel 29 comprises teeth 29a adapted to be driven by tall teeth 23a, 23b on the inner wheel 4 just in the same manner as the teeth 26a on the toothed wheel 26 are driven, and teeth 29b which normally abut against a locking disc 4b disposed on the shoulder of the inner wheel 4 to be locked thereby, but which are adapted to enter the recess 4a (see FIG. 8) in the locking disc 4b to permit a rotation of the toothed wheel 29 as the latter is driven by tall teeth 23a, 23b on the inner wheel 4.

The numeral representations on the respective display wheel 2 to 5 may be provided in known manners as by painting or rotary press, for example, but a transparent sheet S as shown in FIG. 6 may be used for the outer wheel 5. The sheet S may be painted dark for a background except for a portion of polyester film or the like and is formed to define the display window 5a, with the indicia imprinted on the dark background, the sheet being applied around the wheel of a transparent material.

The unit described above operates as follows:

It is initially assumed that the teeth on the gear 28 are located in the hiatus or toothless gap 25a of the gear 25 and that the teeth on the toothed wheel 31 engage the teeth 24 of the gear 25 and the toothed wheel 29 is locked by the locking disc 4b to prevent the rotation of the outer wheel 5. Under this condition, the outer wheel 5 is adapted to be positioned with its display window 5a aligned with the window 7. As the toothed wheel 26 is incrementally driven for rotation by means of the ten's digit minute wheel 3, such rotation is transmitted to the inner wheel 4. However, since the gear 28 is aligned with the hiatus 25a in the gear 25, the rotation of the gear 28 is not transmitted to the outer wheel 5. Thus only the inner wheel 4 continues to be driven for rotation during this phase, causing the numeral representations of 1 to 12 provided thereon to be displayed in the display windows 5a and 7 successively.

Toward the end of the initial one complete revolution of the inner wheel 4, the teeth 23a, 23b on the inner wheel 4 cause the toothed wheel 29 to rotate for one-fourth revolution, whereby the toothed wheel 31 is also rotated one-fourth revolution to be moved out of engagement with the gear 25 to unlock it while rotating the latter through an angle corresponding to one numeral position thereon. As the gear 25 is unlocked from the toothed wheel 31 and rotates through such angle, it is free to rotate in engagement with the gear 28 as is the outer wheel 5. Since the toothed wheel 26 remains in meshing engagement with the teeth 22 on the inner wheel 4, the latter continues to rotate. Thus the inner and outer wheels 4 and 5 rotate together, with the window 5a overlapping the numeral representation of 1, thereby allowing the numeral representations of 13 to 23 and 0 on the outer wheel 5 to be successively displayed through the window 7.

When both inner and outer wheels 4 and 5 complete one revolution, the toothed wheel 29 is again driven by the inner wheel 24 to rotate one-fourth revolution, whereby the toothed wheel 31 is moved into locking engagement with the gear 25 on the outer wheel 5 and the hiatus 25a in the gear 25 moves into alignment with the gear 28, thus completing one cycle of the operation of the unit. In this manner, numeral representations of 0 to 23 on the inner and outer wheels are successively displayed.

It will be appreciated that the means for driving the inner and outer wheels, which in the embodiment are shown to comprise the toothed wheels 26 and 22 and the gears 28 and 25, may be replaced by any other conventional means. Also the means for engaging and disengaging the outer wheel, which in the embodiment is shown as comprising the toothed wheels 29 and 31, may be replaced by other means, for example, by a locking lever which is operated in synchronism with the rotation of the inner wheel. The drive release means which release the gear 25 from the meshing engagement with the gear 28 when the gear 25 is locked may comprise, for example, a solenoid operated clutch which is operated in operative relationship with the rotation of the inner wheel.

In a specific example, when the inner wheel has the indicia 1 through 12 arranged thereon at equi-angular intervals, the outer wheel has arranged thereon a number of indicia equal to the number of indicia on the inner wheel, plus also the transparent window 5a. For example, the outer wheel 5 has arranged thereon the indicia 13 through 23 plus the indicia 0 immediately following the indicia 23. In this case, the display window 5a is arranged between the two lowest indicia 0 and 13.

At the start of a cycle, the indicia 13 is aligned with the display window 7, shown in FIG. 1, and the indicia 12, on inner wheel 4, is aligned with window 5a which is now spaced from display window 7 by one step or one angular interval. Under these conditions, gear 28 meshes with gear 25 and locking gear 31 is rotated 90.degree. from the position shown in FIG. 3, whereby gears 17 and 28 rotate gears 22 and 25 in synchronism with each other. As a result, the indicia 13 through 0 are displayed successively through the display window 7 of FIG. 1. Toward the end of this first revolution, gear 29 is rotated through 90.degree. to re-engage gear 31 with gear 25 to lock gear 25 in the position shown in FIG. 3 wherein gear 28 is out of mesh with gear 25. At this time, window 5a is aligned with the display window 7 of FIG. 1, and gear 17 continues to rotate gear 22 and inner wheel 4 so that the indicia 1 through 12 are successively displayed through windows 5a and 7 during the second complete revolution of inner wheel 4.

While a specific embodiment of the invention has been shown and described in detail, to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

Claims

What is claimed is:

1. An indicia display unit comprising, in combination, an inner wheel bearing a series of indicia on its peripheral surface; an outer wheel telescoped coaxially over said inner wheel and bearing a series of indicia thereon equal to the number of indicia on said inner wheel and carrying a display window interposed between the two terminal indicia of its series; a common shaft rotatably mounting said inner and outer wheels; respective external gear means on said inner and outer wheels and fixed to rotate therewith; drive means operable to step the gear means of said inner and outer wheels through regular angular intervals, each corresponding to one indicia position of the respective wheel, at regular time intervals; said drive means stepping the gear means of said inner wheel through two revolutions per cycle; and locking and release means operable cyclically by said inner wheel to lock the gear means of said outer wheel against rotation by said drive means, and to uncouple said outer wheel gear means therefrom, at the beginning of the first revolution of said inner wheel, and to release the gear means of said outer wheel, and to couple said outer wheel gear means to said drive means, for rotation by said drive means, at the beginning of the succeeding revolution of said inner wheel; said locking and release means being operated by said inner wheel gear means to lock the gear means of said outer wheel against rotation simultaneously with movement of said display window into a display position with one terminal indicia of the series on said inner wheel aligned with said display window; said inner wheel gear means operating said locking and release means to release the gear means of said outer wheel and to rotate said outer wheel gear means into driving connection with said drive means for rotation by said drive means, in synchronism with rotation of said inner wheel gear means, as the other terminal indicia of the series on said inner wheel is moved past said display window at the end of the first revolution, of each cycle, of said inner wheel; said gear means of said outer wheel having a hiatus which, in the locking position of said locking and release means, interrupts driving connection of said drive means to the gear means of said outer wheel.

2. An indicia display unit, according to claim 1 wherein said inner wheel bears numerical representations of 1 to 12 and said outer wheel bears numerical representations of 13 to 23 and 0, said display window being interposed between the representation of 13 and the representation of 0.

3. An indicia display unit according to claim 1, including at least one further wheel bearing indicia of a lower significant order; said drive means comprising carrying transmitting toothed wheel means driven by a carry from said further wheel and the respective gear means on said inner and outer wheels meshing with said toothed wheel means.

4. An indicia display unit, according to claim 3, in which said locking and release means comprises a first toothed wheel meshing with the gear means on said outer wheel when said display window has been stepped into the display position to lock said outer wheel against rotation; and a second toothed wheel cyclically operable by the gear means on said inner wheel at the end of each second revolution of each cycle of said inner wheel to rotate said first-toothed wheel to rotate said outer wheel to effect interengagement of the gear means on said outer wheel with said toothed wheel means.

5. An indicia display unit according to claim 4, in which said first toothed wheel intermittently meshing with the gear means on said outer wheel is a double sector gear with the two sectors diametrically opposite each other; said second toothed wheel, meshing with the gear means on said inner wheel, rotating said double sector gear through 90.degree. to alternately engage and disengage the gear means on said outer wheel.