GB2337833A - An alarm clock - Google Patents

Abstract

There is disclosed a clock 10 including a twenty-four-hour-hand 22, an hour-hand 18 and a minute-hand 20 for displaying the current time in a twenty-four-hour format, which clock 10 further include buttons 28, 30, 32, 33 for setting a twenty-four-hour alarm time. The clock 10 includes an integrated circuit 82 which allows the clock 10 to be in one of four states. In the first operable state, the current time is displayed by the clock 10. In the second operable state, the pre-set alarm time is displayable. In the third operable state, the current time as displayed by the clock 10 is adjustable. In the fourth operable state, the alarm time is adjustable. The clock 10 is allowed to be in only one of these four states at one time. The hands are movable by means of rapid pulsing of motors.

Description

1 A Clock 2337833 This invention relates to a clock and in particular, an

alarm clock incorporating an integrated circuit or a micro-processing unit.

A vast majority of analogue alarm clocks adopt the conventional 12-hour dial face. Human effort is thus required to enable the alarni, e.g. in the evening, to ensure that the alarm will sound off in the morning. In addition, in conventional alarm clocks, the comparison between the preset alarm time and the current time is made mechanically, thus giving rise to a margin of error of roughly 10 minutes.

It is thus an object of the present invention to provide an improved clock in which the aforesaid shortcoming are mitigated, or at least to provide a useful alternative to the public.

According to the present invention, there is 'provided a clock including current time displaying means for displaying the current time in a twentyfour-hour format characterized in that said clock further includes alarm setting means for setting an alarm time distinct within a twenty-fourhour period at which alarm time an alarm signal is given by said clock- An embodiment of the present invention will now be described with reference to the accompany drawings, in which:- Fig. 1 shows a front view of a clock in accordance with the present invention; Fig. 2 shows the arrangement of the gears used in the clock shown in Fig. 1; Fig. 3 Is a block diagram of an integrated circuit used in the clock shown in Fig.

1; Fig. 4 is a state diagram of the integrated circuit shown in Fig. 3; Fig. 5A shows a waveform diagram for the motor drivers A/B used in the clock shown in Fig. 1.) Fig. 5B shows a waveform diagram for the motor drivers C/D used in the clock shown in Fig. 1; and Fi& 6 shows schematically the arrangement of the motor drivers and the respective motors used in the clock shown in Fig. 1.

Referring first to Fig. 1, such shows a front view of a clock according to the present invention as generally designated as 10. The clock 10 is operated by electricity, e.g. batteries. It can be seen that the clock 10 includes a total of three dial faces 12, 14 and 16. The dial face 12 is a conventional twelve-hour dial face, about which an hour-hand 18 and a minute-hand 20 revolve. As in conventional clocks, the hour-hand 18 revolves around the twelve-hour dial face 12 once every twelve hours, and the minute-hand 20 revolves around the twelve-hour dial face 12 once every hour.

The dial face 14 is a twenty-four-hour dial face, and is divided into twentyfour equal parts, each signifying one hour. A twenty-four-hour hand 22 revolves around the twenty- four-hour dial face 14 once every twentyfour hours. As to the dial face 16, such is a sixty-second dial face, and is divided into sixty equal parts. A secondhand 24 revolves around the sixty-second dial face 16 once every minute.

On a ftont panel 26 of the clock 10 are provided a number of slidebuttons 28, 30 -3 and 32. The slide-button 28 is slidably movable between a "Current Time" position in which the clock 10 is in a state in which the current time is displayed, and an "Alarm Tinie" position in which the clock 10 is in a state in which the pre-set alarm time is displayed by the clock 10. The slide-button 30 is slidably movable between a "Resetting Enabled" position in which the clock 10 is in a state in which either the current time or the pre-set alarm time can be reset, and a "Resetting Disabled" position in which the clock 10 is in a state in which such cannot be reset. The slidebutton 32 is slidably movable between an "Alarm On" position in which the alarm is enabled, and an "Alarm Off' position in which the alarm is disabled. A press button 3 3 is also provided on the front panel 26 of the clock 10 for setting the current time or the alarm time.

As shown in Fig. 2, the clock 10 includes a first stepping motor 34 and a second stepping motor 36 for driving the various hands 18, 20, 22, 24. An output gear 38 of the first stepping motor 34 meshes with a first gear 40. A second gear 41, which is integral and moves synchronously with the first gear 40, meshes with a third gear 42 to which a second-shaft 44 is fixedly attached. The second-hand 24 is affixed to a shoulder part 46 of the second-shaft 44. With appropriate arrangement of the gearing ratios among the output gear 38 of the first stepping motor 34, the first gear 40, the second gear 41 and the third gear 42, the second-hand 24 is set to rotate at an average angular speed of 6' per second, i.e. around the sixty-second dial face 16 once every minute.

An output shaft 48 of the second stepping motor 36 meshes with a fourth gear 50. A fifth gear 52, which is integral and moves synchronously with the fourth gear 50, meshes with a sixth gear 54. Fixedly attached to the sixth gear 54 is a minuteshaft 56 and a seventh gear 58. The minute-hand 20 is affixed to a shoulder part 60 of the minute-shaft 56. The seventh gear meshes 58 with an eighth gear 62, which is integral and moves synchronously with a ninth gear 64. The ninth gear 64 meshes with a tenth gear 66 which is integral and moves synchronously with an hour-shaft 68. The hour-hand 18 is affixed. to a shoulder part 70 of the hour-shaft 68. The tenth gear 66 meshes with an eleventh gear 72 (as indicated by the arrow in Fig. 2), which is integral with and moves synchronously with a twelfth gear 74. The twelfth gear 74 meshes with a thirteenth gear 76, which is integral with a twenty-four-shaft 78. The twenty-four-hour-hand 22 is affixed to a shoulder part 80 of the twenty-four-hourshaft 78.

With appropriate arrangement of the gearing ratios among the output gear 48 of the stepping motor 36 and the fourth gear 50 to the thirteenth gear 76:- (a) the minute-hand 20 is set to rotate at an average angular speed of 1/10' per second, i.e. around the twelve-hour dial face 12 once every hour., (b) the hour-hand 18 is set to rotate at an average angular speed of 1/120' per second, i.e. around the twelve-hour dial face 12 once every twelve hours; (c) the twenty-four-hour-hand 22 is set to rotate at an average angular speed of 1/240' per second, i.e. around the twenty-four-hour dial face 14 once every twenty-four hours.

An integrated circuit may be used in the clock 10 for controlling the motors 34, 36 (which drive the two gear trains) via two sets of magnetic stators (to be discussed below). An application specific integrated circuit (ASIC) or a programmed microprocessing unit (NTU) is required to fulfil the function of firing electrical pulses into coils which magnetize the stators (again, to be discussed below). In addition, this ASIC/NPU fulfils the flinction of generating the alarm signal at the pre-set alarm time.

A block diagram of an integrated circuit (IC) 82 which may be used in the clock 10 is shown in Fig. 3. In this block diagram, solidline arrows denote the general direction of flow of signals, dotted-line arrows denote the reading of memory contents from counters and flags (i.e. Time Difference Counter, Current Time Counter, Alarm Time Counter, and Current/Alarm Display Flag) by the Control Unit (all to be discussed below), and broad arrows denote the connection of the relevant units to external devices. In this IC 82, the external devices are the First Stepping Motor 34, the Second Stepping Motor 36, and an External Buzzer or Speaker 84.

The IC 82 includes an Oscillator Unit 86, which generates a reference oscillating signal. For timepieces, such as in the present invention, its frequency is usually 32,768Hz. The signal is obtained by connecting a quartz crystal to specified pads of the IC 82 which connect to the internal oscillating circuit. The signal generated by the Oscillator Unit 86 is transmitted to a Frequency Divider 88. For ASIC implementation, the Frequency Divider 88 is usually composed of a series of flipflops, at one end of which is normally another reference signal of 1Hz. For this application, the Frequency Divider 88 outputs (a) 1H2 1/60Hz and a high ftequency -6signal to a Control Unit 90; and (b) one high (e.g. 2048Hz) and one low (e.g. 2Hz) signal to an Alarm Generation Unit 92 for the composition of an audible modulated alarm pattern signal. The signals and their frequencies used in the composition of the alarm pattern depend on the implementation and alarm pattern intended.

The Control Unit 90 accepts input ftom the defined input switches (S1, S2, S3 and ALI) and determines the behaviour of the IC 82 according to the State Diagram in Fig. 4 (to be discussed below). The Control Unit 90 constantly performs the following functions:(a) updates and reads from a Current Time Counter 94-, (b) updates and reads from an Alarm Time Counter 96.. (c) updates the display by the second-hand 24 by directing Motor Drivers C/D 98 to output a 1Hz signal; (d) determines the number of pulses to be outputted by Motor Drivers A/B 100 to display either the Current Time or the pre-set Alarm Time; calculates the time difference between the Current time and the Alarm time and stores it in a Time Difference Counter 102, which has a resolution down to one minute, and calculates the time difference according to the following formula:- Time Difference = ((Current Time - Alarm Time) mod 2460) minutes The amount of resources needed for this Time Difference Counter is therefore at least 11 bits. The calculation is performed by an Arithmetic Logic Unit (ALU) of the Control Unit 90. If the result of the Time Difference is zero (in binary -7form), it signifies the event of the triggering of the alarm signal; (f) keeps track of whether the Alarm time or the Current time is displayed according to the input on S1 and updates a Current/Alarm Time Display Flag 104 accordingly. The flag is noted by the Control Unit 90 to calculate the number of pulses to be outputted by the Motor Drivers A/B 100; (g) if the contents of the Current Time Counter 94 equal that of the Alarm Time Counter 96, the Control Unit 90 will signal the Alarm Generating Unit 92 to trigger the alarm sequence. In the current implementation, the alarm will then sound for two minutes before it stops.

The Current Time Counter 94 stores the Current Time in an incremental fashion.

As mentioned above, the resolution is down to one minute out of 1,440 (24x60) minutes. The amount of resources needed is thus 11 bits. The Alarm Time Counter 96 stores the pre-set Alarm Time via updates from the Control Unit 90. The Time Difference Counter 102 stores the difference between the Current Time and the Alarm Time.

One pulse per two seconds (i.e. at a frequency of 0.5Hz) is outputted from each of the two pads connected to the Motor Drivers C/D 98 to achieve a 111z stepping pattern via the physical connection of the coil-stator set (as shown in Fig. 6). For this operation, the pulse width (1p,,) is 7. 8125msec, and the pulse-to-pulse width (tpp) is 1 second (see Fig. SB).

Similar to the Motor Drivers C/D 98, two pads are also connected to the Motor Drivers A/B 100 for physical connection to another coil-stator set. The number of pulses outputted at each pad is determined by the Control Unit 90, described as follows:- (a) when the Current Time is displayed, one pulse every two minutes (I/120Hz) is outputted at each of the two pads to achieve a 1160 Hz stepping pattern via the physical connection of the coil-stator set., when the displayed time transits from the Current Time to the Alarm Time or from the Alarm Time to the Current Time, the number of pulses outputted is determined by the time difference between Current and Alarm Time and the Current/Alarm Time Display Flag 104. The pulses are modulated by a high ftequency signal to achieve a rapid transition (e.g. the high frequency signal may be at 50Hz with a 79% duty ratio); during adjustment of the Current Time or the Alarm Time, the number of pulses outputted by the Motor Drivers A/B is determined by the Control Unit 90 in the following manner:- (1) one pulse is to be fired alternately at the Motor Drivers A/B pads for every pressing of S3 for fine adjustment of the displayed time; and (2) a rapid train of pulses is to be fired alternately at the Motor Drivers A/B pads for a continuous pressing of S3 for the purpose of rapidly adjusting the displayed time.

For this application, and as shown in Fig. 5A, the pulse width (tp,') is 15.6125msec, and the pulse-to-pulse width (Ipp) is 1 minute when the Current Time is displayed. Whereas during rapid adjustment of either the Current Time or the Alarm Time and during short transits, the pulse-topulse width (Ipp) should preferably be small (i.e. in the order of a few milliseconds).

The slide button 28 is associated with S1 in Fig. 3, the slide button 30 is associated with S2 in Fig. 3, the slide button 32 is associated with ALI in Fig. 3, and the press button 33 is associated with S3 in Fig. 3.

For adjusting the Current Time, the slide button 28 must be in the Current Time position and the slide button 30 must be in the "Resetting Enabled" position. The user then presses the press button 33, which activates S3, to trigger a train of rapid pulses at the Motor Drivers A/B 100. The user then releases the press button 33 before the desired 24- hourbased Current Time is reached and then fine-tunes this Current Time by hitting the press button 33 once at a time to advance the minute-hand 20 at oneminute intervals, until the desired time is reached. For adjusting the pre-set Alarm Time, the slide button 28 must be in the Alarm Time position. The rest of the procedure is similar to setting the Current Time. In transiting from Current Time to Alarm Time, the minute- hand 20 will move automatically due to the firing of a series of pulses at the Motor Drivers A/B 100 until the pre-set 24-hour-based Alarm Time is reached, and the same situation will occur when transiting from Alarm Time to Current Time.

Fig. 4 shows a four-state State Diagram of the IC 82 used in the clock 10. it should be noted as a preliminary point that "ALF', which is associated with the slide button 32, has no bearing on the state in which the IC 82 is in. This is explicitly si if igni ied by "ALI=Y' in the diagram. This means that whether the alarm is enabled or disabled has no bearing on the state in which the IC 82 is in. While Active Low Logic is used here, depending on the actual implementation, Active High Logic may be used instead. For the reason of simplicity of presentation, the effect of action on S3 is omitted in this diagram. This input is only effective in States C and D. The State Diagram shows the behaviour of the IC 82 in response to different combinations of inputs from the user in an abstract manner. Depending on the method of implementation (i.e. ASIC or a masked MCU), the State Diagram may help formulate an FSM (Finite-State Machine) or Interrupt Service Routines for the Control Unit 90. In other words, the IC 82 is permitted to be in only one of the four States at any given time.

State A is the initial state, in which the clock 10 is in standby mode with the Current Time displayed. In this State, the slide button 28 is in the "Current TimC position, and the slide button 30 is in the "Resetting Disabled" position, and both SI and S2 are in "IUGIT' state. The Motor Drivers A/B 100 emits only a steady pulse of frequency of 1/6011z (i.e. one pulse every sixty seconds). Input on S3 (i.e. from the press button 33) has no bearing on the operation of the clock in this state.

When the slide button 28 is moved to the "Alarm Time" position, S 1 changes to the "LOW' state, and the IC 82 changes fiom State A to State B. In this state, the pre-set Alarm Time is displayed. The Motor Drivers A/B 100 emits a pulse train if the Current Time as shown in State A is different from the pre-set Alarm Time, but regardless of any input on S3. For example, if the Current Time as shown when the IC was in State A is 01:00 and the pre-set Alarm Time is 13.00, then the pulse train emitted to the Motor Drivers A/B 100 consists of 720 (12x60) pulses (i.e. 360 pulses - 11 from each driver). However, if the Current Time as shown in State A is the same as the pre-set Alarm Time, then there will be no pulse train fired into the Motor Drivers A/B 100. Again, input on S3 has no bearing as S3 is only effective in States C and D.

If the slide button 30 is moved to the "Resetting Enabled" position, S2 changes to the "LOW' state, and the IC 82 changes from State B to State D. In this state, the pre-set Alarm Time is adjustable. The Motor Drivers A/B 100 will not emit any pulse train by reason of the change of states from State B to State D, as the pre-set Alarm Time is already shown in State B. The Motor Drivers A/B 100 will only emit a pulse train if S3 is in "Active Low" state. The user presses the press button 33, which holds S3 onto GND and thus causes S3 to change to the "LOW' state, to trigger a train of rapid pulses at the Motor Drivers A/B 100. The user then releases the press button 3 3 before the desired 24-hour-based Alarm Time is reached and then fine-tunes this Alarm Time by hitting the press button 33 once at a time to advance the minute-hand 20 at one-minute intervals, until the desired Alarm Time is reached.

if the slide button 28 is moved to the "Current Time" position, S 1 changes to the 'TUGIT' state, and the IC 82 changes from State D to State C. In this state, the Current Time is adjustable. If the Alarm Time shown in State D is different from the Current Time, the Motor Drivers A/B 100 emits a pulse train until the Current Time is shown. Whilst in State C, the Motor Drivers A/B 100 emits a pulse train only if S3 is in "Active Low" state. The press button 33 may thus be operated to adjust the Alarm Time, in the manner discussed above. It should also be noted that, in this State, the Motor Drivers C/D 98 (which drives the second-hand 24) stops.

If the slide button 30 is moved to the "Setting Disabled" position, S2 changes to the "11IGIT' state, and the IC 82 changes from State C to State A. The Motor Drivers A/B 100 emits no pulse train as the Current Time is already "on display" after any possible adjustment whilst in State C.

The States of the IC 82 may also change in the opposite direction. Starting again from the initial State A, in which the slide button 28 is in the "Current Time" position, and the slide button 3 0 is in the "Resetting Disabled" position, and both S 1 and S2 are in "IUGIT' state. When the slide button 30 is moved to the "Resetting Enabled" position, S2 changes to "LOW' state, and the IC 82 changes to State C. No pulse train will be emitted as the Current Time is already "on display". The user may then adjust the Current Time in the manner discussed above.

The slide button 28 may be moved to the "Alarm Time" position in order to set S I to "LOW' state, and thus changes the IC 82 from State C to State D. The Motor Drivers A/B 100 will then emit a pulse train if the Current Time as shown in State C is different from the pre-set Alarm Time until the pre-set Alarm Time is displayed.

The slide button 30 may be moved to the "Resetting Disabled" position, whereby S2 is changed to "HIGIT' state, and the IC 82 is changed from State D to State B. The Motor Drivers A/B will not emit any pulse train, as the pre-set Alarm Time is already "on display" after any possible adjustment on the Alarm Time performed whilst in State D.

The IC 82 may be returned to State A by moving the slide button 28 to the "Current Time" position, thus bringing S 1 to "IUGIT' state. The Motor Drivers A/B 100 will emit a pulse train if the Current Time is different from the pre-set Alarm Time, until the Current Time is displayed.

As shown in Fig. 6, two pairs of motor drivers A/B and C/D send electrical signals into their respective coils, which in turn generate magnetic fields in their respective stators 106 to drive the stepping motors 34, 36. Opposing magnetic fields are generated across the air gap in the stator 106 which contain the dual-pole magnetic rotor 108. Thus the rotor 108 will rotate at the instant when a pulse is fired into the stator 106.

it can be seen that the above discloses a clock which is easy to operate. In addition, since the comparison of the Current Time and the Alarm Time is made via electronic circuitry, there will not be the wide margin of error noted above.

It should be noted that the word "Time" as used here refers to a 24-hourbased time, i.e. Time as told and displayed by the hour-hand 18, the minute-hand 20, and the twenty- four-hour hand 22.

It should be understood that the above only describes an embodiment whereby the present invention may be carried out, and that various modifications and alterations may be made thereto without departing from the spirit of the present invention.

Claims (1)

1. CLAIMS:-

   1 A clock including current time displaying means for displaying the current time in a twenty-four-hour format characterized in that said clock includes alarm settina means for setting an alarm time distinct within a twenty-four-hour period at which alarm time an alarm signal is given by said clock.

   A clock according to Claim 1 further characterized in that said current time displaying means includes a twenty-four-hour-hand which revolves around a first dial face of said clock.

   A clock accordin. to Claim 2 further characterized in that said current time displaying means includes an hour-hand and a minute-hand.

   A clock according to Claim 3 further characterized in that said secondhand revolves around a second dial face of said clock.

   A clock according to Claim 3 or 4 further characterized in that said minute-hand and said hour-hand revolve around a third dial face of said clock.

   A clock according to any one of Claims to 5 further characterized in that said twenty-four-hour hand, said hour-hand and said minute-hand are driven by a first motor member.

   7. A clock according to any one of Claims 3 to 6 further characterized in that said second-hand is driven by a second motor member.

   8. A clock accordine to Claim 6 or 7 further characterized in that said first motor member and said second motor member are driven by motor driving means.

   9. A clock accordim, to Claim 8 further characterized 'In that said motor driving means is controlled by a microprocessor 10. A clock according to Claim 1 further characterized in that said clock is 5.

   1.

   - 16actuatable to be in one of a plurality of operable states.

   A clock according to Claim 10 further characterized in that said clock is actuatable to be in only one of said plurality of operable states at one time.

   12. A clock according to Claim 10 or 11 further characterized in that said clock is actuatable to be in one of four operable states.

   A clock according to any one of Claims 10 to 12 further characterized in that said clock is actuatable to be in a first operable state in which the current time is displayed by said current time displaying means.

   14, A clock according to any one of Claims 10 to 13 further characterized in that said clock is actuatable to be in a second operable state in which said alarm time set by said alarm setting means is displayable.

   15. A clock according to Claim 14 further characterized in that said alarm time set by said alarm setting means is displayable by said twentyfour-hour-hand, said minute-hand, and said hour-hand.

   16. A clock according to any one of Claims 11 to 15 further characterized in that said clock is actuatable to be in a third operable state in which the current time as displayed by said current time displaying means is adjustable.

   17. A clock according to any one of Claims 11 to 16 further characterized in that said clock is actuatable to be in a fourth operable state in which said alarm time is adjustable.

   18. A clock substantially as herein described and with reference to the accompanying drawings.

   1: 1 : X. 1 c 11 Amendments to the claims have been filed as follows CLAIMS.- 1 A timepiece including current time displaying means for displaying the current time in a twenty-four-hour format, alarm setting means for setting an alarm time distinct within a twenty-four hour period at which alarm time an alarm signal is given by said timepiece, a twenty-four-hour- hand, an hour-hand and a minutehand, wherein said alarm time set by said alarm setting means is displayable by said twenty-four-hour-hand, said minute-hand and said hour-hand.

   2. A timepiece according to Claim 1 wherein said current time displaying means includes said twenty-four-hour-hand which revolves around a first dial face of said timepiece.

   3. A timepiece according to Claim 2 wherein said current time displaying means includes said hour-hand and said minute-hand.

   4. A timepiece according to Claim 3 further including a second-hand which revolves around a second dial face of said timepiece.

   5. A timepiece according to Claim 3 or 4 wherein said minute-hand and said hourhand revolve around a third dial face of said timepiece.

   6. A timepiece according to any one of Claims 3 to 5 wherein said twentyfour-hour hand, said hour-hand and said minute-hand are driven by a first motor member.

   A timepiece according to any one of Claims 3 to 6 wherein said secondhand is driven by a second motor member.

   8. A timepiece according to Claim 6 or 7 wherein said first motor member and said second motor member are driven by motor driving means.

   9. A timepiece according to Claim 8 wherein said motor driving means is controlled by a microprocessor.

   10.

   A timepiece according to Claim 1 wherein said timepiece is actuatable to be in one of a plurality of operable states.

   11. A timepiece according to Claim 10 wherein said timepiece is actuatable to be in only one of said plurality of operable states at one time.

   12. A timepiece according to Claim 10 or 11 wherein said timepiece is actuatable to 13.

   14.

   be in one of four operable states.

   A timepiece according to any one of Claims 10 to 12 wherein said timepiece Is actuatable to be in a first operable state in which the current time is displayed by said current time displaying means.

   A timepiece according to any one of Claims 10 to 13 wherein said timepiece is actuatable to be in a second operable state in which said alarm time set by said alarm setting means is displayable.

   15. A timepiece according to any one of Claims 11 to 14 wherein said timepiece is actuatable to be in a third operable state in which the current time as displayed by said current time displaying means is adjustable.

   16. A timepiece according to any one of Claims 11 to 15 wherein said timepiece is actuatable to be in a fourth operable state in which said alarm time is adjustable.

   17. A timepiece substantially as herein described and with reference to the accompanying drawings.