Alarm Signaling Time Detecting Device for Digital Clock

This invention relates to an alarm signaling time detecting for a digital clock.

In the conventional drum type or leaf type digital clock, it is usual to set a desired alarm signaling time by setting a corresponding graduation on a drum, which has such graduations and digital figures for respective hours, relative to a fixed index.

In such a case, it is very difficult to accurately visually determine on the minute scale the alarm signaling time to which the clock is to be set.

An object of the invention is to overcome the above drawback and permit accurate digital display of the alarm signaling time on the minute scale for facilitating the setting of the alarm signaling time.

According to the invention the above object is achieved by providing first and second detection members for detecting the alarm signaling time in correspondence to hour and minute hand wheels, respectively, and also providing an hour indication drum for displaying the hour unit of the alarm signaling time and a minute indication drum for displaying the minute unit of the alarm signaling time. The indication drums are geared to the respective detection members to allow the positions of the detection members to set continuously by setting the indication drums.

FIG. 1 is a sectional view showing the main construction of a first embodiment,

FIGS. 2a and 2b show guide sections of the minute detection drum and minute detection member in detail;

FIGS. 3 and 4 show some portions in the construction of FIG. 1;

FIG. 5 is a sectional view showing the main construction of a second embodiment, and

FIGS. 6a, 6b, 6c and 6d show switch plates comprising a portion of the construction of FIG. 5.

Now, the preferred embodiments illustrated in the drawings will be described in detail. First, the construction of a first embodiment shown in FIGS. 1 to 4 will be described.

An alarm signaling time indication mechanism will first be described. Designated at 1 is a driving motor, which is meshed with a minute hand wheel 2 for driving the same at a speed of one rotation per 60 minutes. The minute hand wheel 2 is coupled through a well-known ratchet mechanism to a minute leaf drum 3 for rotating the drum only in one direction. The minute leaf drum 3 is secured to a shaft 7. Its right hand end is journalled in a case 5, and it has 60 minute leaves.

As shown in FIG. 3, these minute leaves include first minute leaves 6a having no projection, second minute leaves 6b each provided on the left hand edge with a projection (not shown), third minute leaves 6c each provided at the right hand edge with a projection (not shown) and fourth minute leaves 6d each provided at both the left and right hand edges with respective projections 60 and 61 (not shown). Of these minute leaves, first minute leaves 6a are used when indicating "00" and "01" minutes past a given hour, third minute leaves 6c are used when indicating "02", "03" and "04" minutes past a given hour, first minute leaves 6a are again used when indicating "05" and "06" minutes past a given hour, and so on; two first minute leaves 6a and three third minute leaves 6c are combined and arranged as leaves for indicating up to "44" minutes past a given hour.

Second minute leaves 6d are used when indicating "45" and "46" minutes past a given hour, fourth minute leaves 6d are used when indicating "47," "48" and "49" minutes past a given hour, and so on; two second minute leaves 6d and three fourth minute leaves 6d are combined and arranged for indicating up to "59" minutes past a given hour.

Designated at 8 is an hour leaf drum rotatably supported by the shaft 7, and it has 48 hour leaves 9. A second minute hand wheel 10 is secured to an intermediate portion of the shaft 7, and its boss 10a is rotatably supported by a minute indication drum 20. It has cam holes 10b and a pinion 10c. The pinion 10c is geared through an intermediate hour wheel 11 to an hour hand wheel 8a provided on the hour leaf drum 8.

The hour hand wheel 8a is formed on the left side of the hour leaf drums 8, with cam holes 8b formed in the face of the hour hand wheel 8a.

Designated at 13 is an hour leaf holding spring. When an hour leaf 9 is raised in an interlocked relation to the left hand projections 60 of the second and fourth minute leaves, the hour leaf 9 is held by the spring 13 so that it will be inverted even if it is detached from a second pawl 14b of a feed spring 14, and it is inverted simultaneously with the detachment of the fourth minute leaf 6d indicating "59" minutes past a given hour from a first pawl 14a of the feed spring, at which time "00" minute past the next hour is indicated and also the hour leaf 9 is released from the spring 13 .

Now, an alarm signaling mechanism will be described. Designated at 15 is an alarm signaling time setting knob, which is coupled to a minute indication drum 20 having a 60-minute scale of time graduations 20e provided at five minute intervals for indicating alarm time. The minute indication drum 20 is rotatably supported on one side by an intermediate member 19 secured by screws 24 to the case 5 and on the other side by a side member 18 secured to the intermediate member 19. An hour indication drum 21, which is advanced by one pitch with one rotation of the minute indication drum 20 through a carry gear 17, is rotatably supported on a central boss of the minute indication drum 20. The hour indication drum 20 has alarm time graduations and figures 21e inscribed on its surface. The alarm time figures 20e and 21e provided on the drums can be seen through an alarm signaling time display window 50a on the front plate 50 of the clock. The minute indication drum 20 is provided in its intermediate portion with a click gear 20a, which engages with a click spring 19a projecting from the intermediate member 19 and provides a click stop action at an interval of, for example, five minutes when the knob 15 is rotated. The minute indication drum 20 is also provided adjacent to its right hand end with grooves 20c and ribs 20d between these grooves, as shown in FIGS. 2a and 2b, and a minute detection member 25 is coupled to the minute indication drum 20 such that it is not rotatable but movable in the axial direction with respect to the minute indication drum.

The minute indication member 25 has cams 25a, which can be received in the afore-mentioned cam holes 10a in the second minute hand wheel. The minute indication drum 20 is further provided adjacent to its right hand end with a pinion 20b which is meshed with an intermediate wheel 22, which is in turn guided for rotation by a boss 19c projecting from the intermediate member 19. The intermediate wheel 22 has a pinion 22a which is rotatable with the shaft 7 and meshed with the gear of an hour detection member 26, which is movable relative to the shaft 7. The hour detection member 26 has cams 26a, which can be received in the afore-mentioned cam holes 8b in the hour drum.

Now, an alarm signaling time detecting mechanism shown in FIG. 3 will be described. Designated at 27 is a pair of detecting arms 27a and 27b respectively adapted to cooperate with the afore-mentioned minute and hour detection members 25 and 26, and a pin 27c about which the pair of detecting arms pivot for operating a first switch SW.sub.1.

A second switch SW.sub.2 is adapted to cooperate with the right hand projections of the third and fourth minute leaves 6c and 6d.

A third switch SW.sub.3 is a so-called alarm stopping switch, and it is closed when the user wants to use a buzzer B. The switches SW.sub.1 to SW.sub.3 and buzzer B are connected in series across a power supply E.

An additional description of the detecting mechanism will now be made. Although the alarm signaling time is digitally indicated, since the minute and hour detection members 25 and 26 are coupled through gears to the pinion 20a of the minute indication drum, the phase of the hour detection member 26 changes continuously so that the hour detection member phase is an analog parameter. Thus, even if the minute detection member 25 is designed such that it is received in the second minute hand wheel 10 for a constant period of time (for instance, 5 minutes or 10 minutes), so long as the period during which the hour detection member 26 is received in the holes 8b of the hour drum is set to be within one hour (for instance 30 minutes), even with the setting of the alarm signaling time to an instant near the instant of switching of alarm signaling times, for instance 55 minutes past a given hour, the hour detection member 26 is displaced continuously by an angle corresponding to the afore-mentioned 55 minutes past a given hour, so that there is no possibility of erroneously signaling the alarm.

The operation of the above-described structure will now be described. When it is desired to use the alarm signaling device, the third switch SW.sub.1 is first closed, and then the desired time is set by turning the knob 15 while watching the figures inscribed in the minute and hour indication drums 20 and 21. With the setting of the alarm signaling time the phases of the cams 25a and 26a of the minute and hour indication members 25 and 26 are determined. When the clock is left in this state, the motor 1 rotates the minute hand wheel 2, minute drum 3 and second hand wheel 10 and also rotates the hour drum 8 through the intermediate hour wheel 11. In this state, the cam hole 8b of the hour drum 8 and the cams 26a of the hour detection member 26 first come to coincidence with one another, so that the hour detection member 26 is now capable of being moved in the rightward direction by the force of the first switch SW.sub.1 through the first detecting lever 27. At this time, however, the cams 25a of the minute direction member and cam holes 10b of the second minute hand wheel are not yet brought into coincidence with one another, and thus the rotation of the first detecting lever 27 is not caused. Thus, the first switch SW.sub.1 is not closed.

With further rotation of the hour hand wheel 8a the cams 25a of the minute detection member 25 eventually come to coincidence with the cam holes 10b of the second minute hand wheel 10. At this time, the minute detection member 25 is capable of being moved rightwards. Thus, the detecting lever 27 is rotated counterclockwise by the force of the first switch SW.sub.1 to close the first switch SW.sub.1. At this time, the tip of the second switch SW.sub.2 is co-operating with the right hand projection 61 of the third or fourth leaf 6c or 6d as shown in FIG. 3, so that the second switch SW.sub.2 remains "off," and the buzzer B is not operated yet. When the leaf indicating the "59" minutes past a given hour, as shown in FIG. 3, is inverted to "00," there is no longer any projection restricting the second detecting lever. As a result, the second switch SW.sub.2 is closed by its own spring force, whereby the buzzer B is operated.

At this time, the operation of the buzzer B can be stopped by opening the third switch SW.sub.3. If the buzzer is left sounding without taking the measure of stopping it, after a lapse of a couple of minutes from the triggering of the buzzer B the second switch SW.sub.2 is again operated by the right hand projection of 61 of the third minute leaf 6c and is thus closed, thus stopping the buzzer B once. When the time is further elapsed until "05" minutes past the given hour is indicated, the projection again disappears, so that the second switch SW.sub.2 is closed again to operate the buzzer B. In this way, if the measure of stopping the buzzer sound is not taken, the buzzer B is repeatedly caused to sound for every five minutes until the cams 25a of the minute detection member escapes from the cam holes 10b of the second minute hand wheel.

A second embodiment shown in FIGS. 5, 6a, 6b, 6c and 6d will now be described.

This embodiment is different from the first embodiment in the hour leaf drum advance mechanism and alarm signaling time detection mechanism, and these different portions will be described.

In the alarm signaling time indicating mechanism, a minute leaf drum 103 having minute leaves 106a to 106d similar to those in the first embodiment is provided at the left hand end with an integral pinion 103a which meshes with an intermediate hour wheel 111. An hour leaf drum 108 is also provided at its right hand end with an hour hand wheel 108a meshing with a pinion 111a provided on the intermediate hour wheel 111.

Now, the alarm signaling time indicating mechanism will be described. Designated at 125 is a minute detection member which is integral with a minute indication drum 120 like the first embodiment. It has a first switch member 130 as shown in FIG. 6a, which is secured to the surface of the minute detection member 125. The first switch 130 has a disc portion 103a which is always in contact with a slide contact piece 135 of a first switch SW.sub.1 and a contact arm 130b extending rightwards through a hole formed in the minute direction member 125.

Designated at 110 is a second minute hand wheel secured to a shaft 107, and it has a second wheel member 131 as shown in FIG. 6b, secured to its surface. The second switch member 131 has a disc portion 131a and a sector-shaped switch section 131b penetrating and extending parallel to the left hand side of the second minute hand wheel 110. The sector-shaped switch section 131b is capable of being brought into contact with the contact arm 131b of the first switch member.

Designated at 126 is an hour detection member which is coupled through a second intermediate hour wheel (not shown) to a pinion 120b of the minute indication drum like the first embodiment, and it has a third switch member 132 as shown FIG. 6c, secured to its surface. The third switch member 132 has a first contact arm 132a extending leftwards and always in contact with the disc portion of the first switch member and a second contact arm 132b penetrating and rightwardly extending through a hole in the hour detection member 126. The hour leaf drum 108 has a fourth switch member 133 as shown in FIG. 6d, secured to the left side of the drum. The fourth switch member 133 has a disc portion 133a which is always in contact with a contact piece 134 of the first switch SW.sub.1 and a sector-shaped section 133b capable of being brought into contact with the second contact arm 132b of the third switch member. The first switch SW.sub.1 is connected in series with a second switch SW.sub.2, a manually operable third switch and a buzzer B across a power supply E as in the first embodiment.

In operation, when an alarm signaling time which has been previously set is approached as the clock is being driven, the sector-shaped switch section 113b of the fourth switch member 133 is first brought into contact with the second contact arm 132b of the third switch member. At this time, the second switch member 131 and first switch member 130 are not yet in contact with each other, so that the buzzer B is not operated yet. When the preset alarm signaling time is further approached, the sector-shaped switch section 131b of the second switch member is at this time brought into contact with the contact arm 130b of the first switch member, whereby the two slide contact pieces 135 and 134 are electrically connected to each other. As a result, the first switch SW.sub.1 is closed. However, the second switch SW.sub.2 is raised at this time by the right hand projection 161 of the corresponding minute leaf and is not closed, so that the buzzer B is not operated yet.

When the alarm signaling time is reached, causing the inversion of the fourth minute leaf 106d, the second switch SW.sub.2 is no longer restricted by any projection so that it closes itself by its own force. With the closure of the second switch SW.sub.2 the whole circuit loop is closed, whereby the buzzer B is operated. The subsequent operation is the same as in the case of the first embodiment, so that it is not described here.

As has been shown, according to the invention the alarm signaling time is indicated in minutes by digital figures, so that the user can accurately set the desired time. In addition, as has been shown in the second embodiment, the alarm signaling device can be accurately started at the desired time by using the minute leaves for the final detection of the preset alarm signaling time.