Alarm Signaling Time Indicating Mechanism for an Alarm Clock

The present invention relates to improvements in an alarm signaling time indicating mechanism capable of digital indication of an alarm signaling time for an alarm clock capable of analog time indication.

Generally, in an analog alarm clock which indicates time with indication hands, it has been usual to indicate an alarm signaling time by an analog indication. Since such a conventional analog alarm clock has a single alarm signaling time indicating hand, it has been difficult to set an alarm signaling time correctly to the minute scale.

To overcome such a disadvantage of a conventional analog alarm clock, analog alarm clocks capable of displaying an alarm signaling time by digital indication have been proposed. An alarm clock of the present invention capable of displaying an alarm signaling time by an digital indication and having features as mentioned earlier consists of two elements, namely, a clock movement comprising a motor, an hour detection wheel and a minute detection wheel which are associated respectively with an hour time wheel and a minute time wheel which are driven by the motor and other necessary components, and a block comprising a minute indication drum and an hour indication drum which are provided to display an alarm signaling time by a digital indication and transmission wheels interlocking the minute indication drum and both of the detection wheels, and featured by disposing the block beside the clock movement and attaching the same to the clock movement. According to the present invention, the clock movement and the block are capable of being assembled individually and interconnected thereafter. Thus the clock assembling operations are facilitated and an alarm signaling time can be displayed with large characters as the alarm signaling time is indicated on the drums.

Furthermore, according to the present invention, the center shaft of the transmission wheel included in the block and the center shaft of the second transmission wheel included in the clock movement are interconnected by splines, the spline joint is axially movable toward the block, and a guide means capable of varying the block attaching position is formed in the attaching part of the block, which enables the appropriate adjustment of the interval between the block and the center of the time indication hands according to the size of the frame of the alarm clock by appropriately and selectively deciding the block attaching position, and thereby the freedom of the design of the alarm clock is enhanced. Still further, according to the present invention, supporting the means for supporting alarm signaling time indicating wheels are formed in addition to the block attaching part in the case of the clock movement, and hence an alarm signaling time indicating unit can optionally and selectively be disposed in the exterior or in the interior of the clock movement.

FIG. 1 is a sectional view showing parts of an embodiment of the present invention;

FIG. 2 is a sectional view showing other parts of the embodiment of FIG. 1;

FIG. 3 is a sectional view taken along line I--I of FIG. 1;

FIG. 4 is a plan view of part of the embodiment of FIG. 1;

FIG. 5 is an external view of the embodiment of FIG. 1;

FIG. 6 is a back view of a clock movement;

FIG. 7 is a sectional view showing parts of another embodiment of the present invention, in which an alarm signaling time indicating unit is disposed inside a clock movement; and

FIG. 8 is an external view of the alarm clock of FIG. 7.

Preferred embodiments of the present invention will be described hereinafter in connection with the accompanying drawings.

A case 1 is formed of a plastic and is provided, in the left end thereof as viewed in FIG. 1, with internally threaded bosses 1a for fixing a middle plate 2, which will be described later, and a cover 3 to the case 1, on the right end thereof, with internally threaded openings or bosses 1b for fixing a first block side plate 20 to the case 1 and, in the bottom wall thereof, with a hole 1c for rotatably supporting an hour time wheel 11, a hole 1d for rotatably supporting a minute alarm signaling time indicating wheel 34 (see FIG. 7), a shaft 1e for rotatably supporting an hour alarm signaling time indicating wheel 35, a shaft 1f for rotatably supporting an intermediate hour wheel 10, a shaft 1g for rotatably supporting a third transmission wheel 16, two supporting parts 1h each having a U-shaped groove for rotatably supporting a second transmission wheel 17 and two supporting parts 1i each having a U-shaped groove for rotatably supporting a detection lever 18. The middle plate 2 also is formed of a plastic and has a hole for rotatably supporting an intermediate wheel 6, a shaft 2a for rotatably supporting the intermediate hour wheel 10, a shaft 2b for rotatably supporting the minute alarm signaling time indicating wheel 34, a boss 2c for rotatably supporting a minute time wheel 8 having a central hole for receiving the shaft 5 of a second time wheel therethrough, a boss 2d for rotatably supporting the detection lever 18 in cooperation with the supporting parts 1i and a hole receiving the shaft of the third transmission wheel 16 therethrough. The cover 3 also is formed of a plastic and has holes for rotatably supporting the intermediate shaft 6, the shaft 5 of the second time wheel and the shaft of the third transmission wheel 16, and a side wall 3a for rotatably supporting the second transmission wheel 17 in cooperation with the supporting parts 1h of the case. The middle plate 2 and the cover 3 are placed on the bosses 1a of the case 1 and are fixed to the case by screws 19.

The case 1, the middle plate 2, the cover 3 and gear trains formed in the case constitute an analog clock movement, and the case 1 and cover 3 comprise a casing for the analog clock movement.

The constitution of a block or unit for displaying an alarm signaling time by digital indication, comprises an hour indication drum 22, a minute indication drum 21, which will be described later, and other peripheral parts will be described hereinafter.

The digital time display unit or block comprises a casing having a first block side plate 20 formed of a plastic. One of the walls of the first block side plate 20, namely, a T-shaped wall, has a hole 20a for rotatably supporting the shaft of a first transmission wheel 24, a boss 20b for rotatably supporting the minute indication drum 21, a shaft 20c for rotatably supporting a carrying wheel 25, and internally threaded bosses 20d for fixing a second block side plate 23 to the first block side plate 20. The other side wall of the first block side plate 20 has a guide surface 20e for guiding the wall when attaching the block to the clock movement, and two slots 20f formed in the guide surface for receiving therethrough screws for fixedly connecting the block to the clock movement. The second block side plate 23 also is formed of a plastic and has a hole 23a for rotatably supporting the shaft of the first transmission wheel 24, a hole 23b for rotatably supporting the minute indication drum 21, and a click stop spring part 23c for click-stoppping the minute indication drum 21. The second block side plate 23 is fixed to the bosses 20d of the first block side plate 20 by means of screws 26.

The constitution of a gear train for time indication will be described hereinafter. The second time wheel 4 is provided integrally with a pinion 4a and is fixed to a shaft 5. The shaft 5 is supported rotatably at one end thereof on the cover 3. The other end of the shaft 5 penetrates through and is supported rotatably by the pipe 8a of the minute time wheel 8. A second indication hand 13 is attached to the free end of the shaft 5. The second time wheel 4 is driven by a motor, not shown. The intermediate shaft 6 is provided integrally with a pinion 6a which engages the minute time wheel 8, a groove 6b for rotatably supporting the intermediate wheel 7 engaging the pinion 4a of the second time wheel 4, and a knob 6c for carry out a time correcting operation from outside the cover 3. The intermediate shaft 6 is supported rotatably on the middle plate 2 and the cover 3. The intermediate wheel 7 is connected to the intermediate shaft 6 for slipping rotation by means of a known method so that the intermediate wheel 7 will be caused to slip relatively to the intermediate shaft 6 when a predetermined torque is applied to the intermediate wheel 7. The minute time wheel 8 engaging the pinion 6a of the intermediate shaft is provided integrally with a pinion 8a, a pipe 8b and a cam groove 8c which will be described later. The pipe 8b is supported rotatably on the boss 2c of the middle plate 2 at the upper end thereof. The other end of the pipe 8b penetrates through and is supported rotatably in the pipe 11a of the hour time wheel 11. A minute hand 9 is fixed to the free end of the pipe 8b. The intermediate hours wheel 10 engaging the pinion 8a is provided integrally with a pinion 10a and is supported rotatably on the shaft 1f of the case and the shaft 2a of the middle plate. The hour time wheel 11 engaging the pinion 10a is provided integrally with a pipe 11a and a cam groove 11b which will be described later. The pipe 11a is supported rotatably in the hole of the case 1 and receives the pipe 8b of the minute time wheel 8 rotatably therethrough. An hour hand 12 is fixed to the free end of the pipe 11a.

The gear train of the alarm signaling time detecting mechanism will be described hereinafter. A minute detection wheel 14 and a protrusion 14a are formed integrally and are located between the minute time wheel 8 and the hour time wheel 11. An hour detection wheel 15 and a protrusion 15a are formed integrally. The hour detection wheel 15 is disposed under the hour time wheel 11 and is supported rotatably on the pipe 11a of the hour time wheel penetrating through the central part of the hour detection wheel 15. A third transmission wheel 16, a gear 16a engaging the minute detection wheel 14, a pinion 16b engaging the hour detection wheel 15 and a crown gear 16c engaging a second transmission wheel 17 which will be described later are formed integrally. The third transmission wheel 16 is supproted rotatably on the shaft 1g of the case and in the hole of the cover. The second transmission wheel 17 engaging the crown gear 16c of the third transmission wheel is supported rotatably on the two supporting parts 1h each having a U-shaped groove of the case and on the side wall 3a of the cover. One end of the center shaft of the second transmission wheel 17 projects outside from the case 1. A center hole 17a having two grooves 17b as illustrated in FIG. 3 for receiving the splined shaft of the first transmission wheel 24 is formed in the right end of the center shaft of the second transmission wheel 17 outside the case 1 to connect the first transmission wheel 24 to the second transmission wheel 17 nonrotatively and axially movably with respect to the second transmission wheel 17.

The gear train of the alarm signaling time detecting mechanism formed in the clock movement is constituted as described hereinbefore. The gear train of the indication mechanism to indicate an alarm signaling time formed in the block will be described hereinafter. A knob 27 is connected to the minute indication drum 21 having minute-scale alarm signaling time graduations 21a marked up to 60 minutes at intervals of 5 minutes. The minute indication drum 21 is supported rotatably on the boss 20b of the first block side plate at one end thereof and in a hole 23b formed in the second block side plate at the other end thereof. The hour indication drum 22 adapted to be carried once every full rotation of the minute indication drum 21 through a carrying wheel 25 is supported rotatably on the central boss of the minute indication drum 21. Hour-scale alarm signaling time graduations 22a are marked on the hour indication drum 22. Both the alarm signaling time graduations 21a and 22a marked on both the minute and the hour indication drums are visible through an alarm signaling time indicating window 29 formed beside the dial 28 of the clock as shown in FIG. 5. The minute indication drum 21 is provided internally with teeth 21b which engage a click stop spring 23c projecting from the second block side plate 23 to click-stop the minute indication drum 21 at every graduation corresponding, for example, to an interval of five minutes when the knob 27 is turned. An indication drum gear 21c is formed integrally with the minute indication drum 21 at the right end of the minute indication drum 21. The first transmission wheel 24 engaging the indication drum gear 21c is supported rotatably in the hole 20a of the first block side plate at one end thereof and in the hole 23a of the second block side plate at the other end thereof. The center shaft of the first transmission wheel 24 extends in parallel to the common center axis of the minute indication drum and the hour indication drum. The left end 24a of the center shaft of the first transmission wheel projects outside from the first block side plate 20. Two external splines 24b as shown in FIG. 3 are formed on the left end 24a of the center shaft of the first transmission wheel so that the first transmission wheel 24 is connected to the second transmission wheel 17 nonrotatively and axially movably with respect to the second transmission wheel 17. Indicated at 30 is a retainer fitted in a groove 24c formed in the middle portion of the center shaft of the first transmission wheel to restrict the rightward movement of the first transmission wheel.

The structure of the attaching part of the block for attaching the block to the clock movement will be described hereinafter. First the center shaft of the first transmission wheel 24 is placed in alignment with the second transmission wheel 17, and then the left end 24a of the first transmission wheel is inserted into the center hole 17a of the second transmission wheel 17. Then, the guide surface 20e of the first block side plate 20 is placed on the upper surface of the cover 3 and screws 31 are screwed through the two slots 20f formed in the first block side plate into the bosses 1b of the case 1 to fix the block to the case. Thus the center shafts of the first transmission wheel or member 24 and the second transmission wheel or member 17 are interconnected through the engagement of the internal and the external splines, and thereby the first and the second transmission wheels are able to rotate as a unit. The length of the spline joint formed by the center hole 17a of the second transmission wheel and the left end 24a of the first transmission wheel is designed so that the spline joint will remain effective as far as the block is screwed to the clock movement at a position within the longitudinal range of the slot 20f. Accordingly, the block can be fixed to the clock movement after selectively and appropriately deciding the interval between the block and the clock movement.

The structure of a detection switch for detecting an alarm signaling time will be described hereinafter. A cam groove 8c is formed in the minute time wheel 8, while a protrusion 14a is formed in the minute detection wheel 14 so as to correspond to the cam groove 8c. The phases of the cam groove 8c and the protrusion 14a coincide for a predetermined period of time once in an hour to enable the axial shift of the minute detection wheel 14. Similarly, a cam groove 11b is formed in the hour time wheel 11, while a protrusion 15a is formed in the hour detection wheel 15 so as to correspond to the cam groove 11b. The phases of the cam groove 11b and the protrusion 15a coincide for a predetermined period of time once every twelve hours to enable the axial shift of the hour detection wheel 15. These two sets of cam grooves and protrusions constitute a well known alarm signaling time detecting mechanism. A detection lever 18 for detecting the axial shift of the minute detection wheel 14 is interposed between the minute detection wheel 14 and the hour time wheel 11, the detection lever 18 being supported rotatably by the supporting parts 1i of the case and the boss 2d of the middle plate and provided with a pressing part 18a located in contact with a movable contact piece 32. The movable contact piece 32 is formed of an elastic conductive material, disposed between the hour detection wheel 15 and the case 1, strained resiliently so as to shift the minute detection wheel 14 upward through the hour detection wheel 15 and the detection lever 18 and provided with a contact 32a constituting in combination with a fixed contact piece 33 formed of a conductive material a switch which is closed when the minute and the hour detection wheels 14 and 15 shift upward. A series connection of the detection switch consisting of the movable contact piece 32 and the fixed contact piece 33, a power source E and a buzzer B constitutes an alarm signal circuit which actuates an electrical alarm signaling unit.

The action of the alarm clock thus constituted will be explained hereinafter. When the alarm signaling time setting knob 27 is turned, the minute indication drum 21 connected to the alarm signaling time setting knob 27 makes click-stop stepping rotation and the minute-scale alarm signaling time graduations 21a changes sequentially according to the click-stop stepping rotation of the minute indication drum 21. The minute indication drum 21 turns the hour indication drum 22 through the lost-tooth carrying wheel 25 and a well known intermittent feed mechanism by one-twelfth of a full rotation every one full rotation thereof so that the hour-scale alarm signaling time graduation 22a is changed by a graduation corresponding to one hour. Thus the minute-scale and the hour-scale alarm signaling time graduations are changed to set a desired alarm signaling time. The indication drum gear 21c of the minute indication drum 21 engages the first transmission wheel 24, the first transmission wheel 24 is connected at the left end 24a of its shaft to the second transmission wheel 17 by means of the spline joint and the second transmission wheel 17 engages the crown gear 16c of the third transmission wheel 16. The gear 16a of the third transmission wheel 16 engages the minute detection wheel 14 and the pinion 16b of the third transmission wheel 16 engages the hour detection wheel 15. Accordingly, the minute detection wheel 14 and the hour detection wheel 15 also rotate as the knob 27 is turned. Thus the respective phases of the protrusion 14a of the minute detection wheel and the protrusion 15a of the hour detection wheel are decided as an alarm signaling time is decided.

The time indication gear train of the clock movement is driven by the motor, not shown, with a desired alarm signaling time thus set. Then, the minute time wheel 8 is rotated at a rate of one full rotation every one hour and the hour time wheel 11 is rotated at a rate of one full rotation every twelve hours and the cam groove 8c of the minute time wheel and the cam groove 11c of the hour time wheel are rotated accordingly. As time passes, the phases of the cam groove 8c of the minute time wheel and the protrusion 14a of the minute detection wheel and the pahses of the cam groove 11b of the hour time wheel and the protrusion 15a of the hour detection wheel coincide simultaneously. Then, the hour detection wheel 15 is shifted upward by the resilient force of the movable contact piece 32, the minute detection wheel 14 is shifted upward by the detection lever 18 as the detection lever 18 is pushed at the pressing part 18a by the movable contact piece 32 to be turned in a clockwise direction as viewed in FIG. 2 and the movable contact piece 32 comes into contact with the fixed contact piece 33, so that the alarm signal circuit is closed and the buzzer B generates an alarm signal sound. The buzzer keeps sounding while the phases of the cam groove 8c of the minute time wheel and the protrusion 14a of the minute detection wheel remain coincided with each other.

The description of the present invention has been made hereinbefore with reference to an alarm signaling time indicating mechanism, wherein the block for the digital indication of an alarm signaling time is disposed outside the clock movement. Further description of the present invention will be made with reference to an alarm signaling time indicating mechanism having an alarm signaling time indicating unit disposed inside the clock movement, in connection with FIGS. 7 and 8. This alarm signaling time indicating mechanism is not provided neither with block nor with the second transmission wheel 17. Alternatively, a minute alarm signaling time indicating wheel 34 marked with minute-scale alarm signaling time graduations 34a, for example, 00, 05, . . . , 55, and integrally having a tooth 34b which engages the teeth of an hour alarm signaling time indicating wheel 35 to drive intermittently and a click-stop gear 34c is supported rotatably in the hole of the case 1 and a shaft 2b formed in the middle plate 2. The hour alarm signaling time indicating wheel 35 marked with hour-scale alarm signaling time graduations 35a, for example, 1, 2, . . . , 12, and adapted to be driven intermittently by the tooth 34 b of the minute alarm signaling time indicating wheel is supported rotatably on a shaft 1e formed in the case 1. The minute-scale and the hour-scale alarm signaling time graduations 34a and 35a are displayed within the dial as illustrated in FIG. 8. An alarm signaling time setting knob 36 is attached by a press-fit to the upper end 16d of the third transmission wheel 16.

The action of the alarm signaling time indicating mechanism thus constructed will be described hereinafter. As the third transmission wheel 16 connected to the knob 36 is rotated by turning the knob, the gear 16a of the third transmission wheel 16 drives the minute alarm signaling time indicating wheel 34 to change the minute-scale alarm signaling time graduations according to the click-stop stepping rotation of the minute alarm signaling time indicating wheel 34. The hour alarm signaling time indicating wheel 35 is turned by one-twelfth of a full rotation every full rotation of the minute alarm signaling time indicating wheel 34 by the tooth 34b of the minute alarm signaling time indicating wheel, so that the hour-scale alarm signaling time graduation is changed by a graduation corresponding to one hour. Thus the minute-scale and the hour-scale alarm signaling time graduations are changed to set a desired alarm signaling time. As mentioned earlier, the gear 16a of the third transmission wheel 16 engages the minute detection wheel 14 and the pinion 16b of the third transmission wheel engages the hour detection wheel 15, hence the minute and the hour detection wheels 14 and 15 also are turned as the knob 36 is turned and the respective phases of the protrusion 14a of the minute detection wheel and the protrusion 15a of the hour detection wheel are decided accordingly. The other actions of this alarm signaling time indicating mechanism are the same as those of the alarm signaling time indicating mechanism having the block for indicating an alarm signaling time disposed outside the clock movement.

As described hereinbefore, according to the present invention, the alarm signaling time indicating unit including alarm signaling time indication drums for indicating an alarm signaling time and other associated parts can be assembled in a block separately from the clock movement, and hence the clock assembling steps are facilitated. Furthermore, since the position of the block of the alarm signaling time indicating unit relative to the clock movement is variable, the interval between the center of the indication hands of the clock movement and the alarm signaling time indicating unit can optionally be decided, which enhances the freedom of the design of the frame of the alarm clock. Still further, the supports for supporting the alarm signaling time indicating wheels are formed in the case of the clock movement and in the necessary parts, and thereby an alarm signaling time indicating unit can be disposed inside the clock movement instead of the separate block simply by supporting the alarm signaling time indicating wheels by the supports, which diversifies the variety of the products.