US3808791A - Electric clock - Google Patents

Electric clock Download PDF

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Publication number
US3808791A
US3808791A US00333875A US33387573A US3808791A US 3808791 A US3808791 A US 3808791A US 00333875 A US00333875 A US 00333875A US 33387573 A US33387573 A US 33387573A US 3808791 A US3808791 A US 3808791A
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United States
Prior art keywords
motor
time display
rotation
electric clock
recited
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Expired - Lifetime
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US00333875A
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English (en)
Inventor
H Hara
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Sony Corp
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Sony Corp
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Publication date
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    • G—PHYSICS
    • G04—HOROLOGY
    • G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C3/00—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means
    • G04C3/14—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means incorporating a stepping motor
    • G—PHYSICS
    • G04—HOROLOGY
    • G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C17/00—Indicating the time optically by electric means
    • G04C17/0075—Indicating the time optically by electric means by drums or drum-like devices

Definitions

  • the present invention relates generally to an electric clock, and more particularly to a battery operated electric clock.
  • an electric motor In some battery operated electric clocks, an electric motor is driven by the electric power from a battery such as a dry cell and the rotation of the motor is used to drive the hand of the electric clock through a gear device. In some other types of electric clocks, an electric motor is energized intermittently and at the time when the motor is energized a spring is wound up to drive the hand of the electric clock.
  • an electric clock which comprises a self-contained power source, a semiconductor switching element, an electric motor whch is connected with the power source through the semiconductor switching element and is drivingly controlled by the semiconductor switching element, a magnet moved by the motor, and an on/off switch for controlling the semiconductor switching element' and which is responsive to the position of the magnet, whereby the motor is energized during one cycle of movement of the magnet.
  • FIG. 1 is a plan view illustrating one embodiment of an electric clock according to the invention
  • FIG. 2 is a cross-sectional view taken generally along the line IIII in FIG. 1;
  • FIG. 3 is an enlarged front view of the reed switch used in the electric clock shown in FIGS. 1 and 2, which is used for explaining the operation of the reed switch;
  • FIG. 4 is a schematic diagram showing a circuit for driving the electric motor used in the electric clock of the invention.
  • FIG. 5 is a block diagram showing an example of the electric clock circuit used in the present invention including a motor and time display means.
  • reference numeral '10 designates a generally U-shaped frame which supports a fixed shaft 11.
  • a time display device or time display means designated generally by reference numeral 12, is rotatably supported by the fixed shaft 11.
  • the time display means 12 includes a first drum 13 for displaying the figure of hours, a second drum 14 for displaying the figure of 10 minute order and a third drum 15 for displaying the figure of minute order.
  • the drums 13 to 15 are inscribed thereon with numerals of 0 to 12, 0 to 5 and 0 to 9, respectively.
  • the frame 10 further supports a second fixed shaft 16 on which first and second drive gears 17 and 18 are rotatablysupported.
  • the first drive gear 17 has first pegs 17a, which engage with pegs 13a provided on the first drum 13 on one of its side surfaces, and second pegs 17b, which engage with pegs 14b provided on the second drum 14 on its side surface which opposes the one surface of the first drum 13.
  • the second drive gear 18 also has first pegs 18a, which engage with pegs 14a provided on the second drum 14 on its other side surface, and second pegs 18b, which engage with pegs 15b provided on the third drum 15 on its side surface which opposes that of the second drum 14 as shown in FIG. 1.
  • drum 14a, 18a, 18b and 15b in reverse order of driving engagement from left to right as viewed in FIG. 1 is such that for each complete revolution of drum l5 drum 14 is advanced one-sixth of a revolution. For each' complete revolution of drum l4, drum 13 is advanced onetwelfth of a revolution.
  • the third drum 15 is further provided with a ratchet wheel 19 on itsright side surface in FIG. 1, which ratchet wheel 19 engages with a drum drive mechanism generally designated as 20 in FIG. 1 which will now be described in detail.
  • the drum drive mechanism 20 includes a DC motor 21 which is rotated one revolution per minute by a motor control circuit to be described in detail hereinafter, a magnet sensitive switch 22 such, for. example, as a reed switch, and a cam 23.
  • the DC motor 21 is mounted on a sub-frame 26 which is attached to the U- shaped frame 10 by means of rods 24 and 25.
  • the motor 21 has a worm gear 27 on its rotary shaft.
  • a first rotatable shaft 30 is rotatably supported between the frame 10 and the subframe 26.
  • the shaft 30 has mounted thereon a first gear wheel 28 engaged with the worm gear 27 and a second gear wheel 29.
  • a second rotatable shaft 32 which has mounted thereon a third gear wheel 31 engaged with the second gear wheel 29,
  • the cam 23 is attached to the second rotatable shaft 32 at its projecting end and has a curved cam surface with a peak 23a on one end, as shown in FIGS. 1 and 2.
  • a swing lever 35 is rotatably supported on the second fixed shaft 16 and is biased to rotate in the counterclockwise direction as viewed in FIG. 2 by means of a coil spring which is not shown.
  • the swing lever 35 has a pin 36 which contacts with the curved cam surface of the cam 23 and a pawl 37 which is pivotably mounted on the lever 35 and which engages with the ratchet wheel 19.
  • the pawl 37 is biased to the clockwise direction by means of a coil spring (though not shown) in FIG. 2, while the ratchet wheel 19 is prevented from reverse rotation by a leaf spring (not shown).
  • a fixed shaft 40 supported by the frames 10 and 26, has a lever 39 pivoted thereto at one of its ends.
  • the lever 39 has a magnet 38 attached at its other end which may oppose the reed switch 22.
  • the lever 39 is biased to the counterclockwise direction by a coil spring 41 wound on the shaft 40 (refer to FIGS. 1 and 2) and has mounted thereon an extension plate 43 which may engage with a cam plate 42 fixed on the second rotatable shaft 32 as shown in FIG. 3.
  • the DC motor 21 is connected in'series with a semiconductor switching element 50 (which is a transistor in the illustrated embodiment) and a battery 51.
  • the switch 22 is connected between the battery 51 and a base electrode b of the transistor 50.
  • An emitter electrode e of the transistor 50 is connected in series through the battery 51 and the DC motor 21 to its collector electrode 0.
  • the switch 22 is kept in its OFF-state.
  • the switch 22 is closed in its ON- state and the switching element 50 is biased into its conductive state. Power from the battery 51 is then supplied to rotate the motor 21. In the normal state, the magnet 38 is apart from the switch 22 and the DC motor 21 stops its rotation.
  • the base electrode b of the transistor 50 is supplied with a pulse at a predetermined time, for example once a minute, from a clock circuit which includes a quartz oscillator55 for generating a signal with a frequency, for example, of 32,768 KI-Iz and first and second frequency dividers 56 and 57.
  • the divider 56 converts the signal with frequency of 32.768 KI-iz into a signal with a frequency of 1 Hz
  • the divider 57 is a counter with a scale of 60 and a reset terminal 57a. Accordingly, from the divider 57 there is derived one pulse per 1 minute or 60 seconds.
  • the reset terminal 57a of the divider 57 is supplied with a pulse from an external source not shown)in association with a zero reset pin (not shown) of the third drum to clear the contents of the counter 57 to be zero. This operation will be described latter on.
  • the transistor 50 In operation, when one pulse is applied to the base electrode b of the transistor 50 from the divider 57 in the clock circuit, the transistor 50 is made ON to energize the DC motor 21.
  • the rotation of the DC motor 21 is transmitted to the second rotatable shaft 32 through the worm gear 27, the gear 28, the shaft 30, and the gears 29 and 31, with the result that the cam 23 and the cam plate 42 fixed to the second rotatable shaft 32 are rotated.
  • the peak portion 42a of the cam plate 42 disengages from the extension plate 43 of the lever 39, thereby allowing the magnet 38 to approach the reed switch 22 with the result that the reed switch 22 is turned ON to hold the transistor in its ON-state even if no pulse is applied to its base electrode b from the divider 57.
  • the DC motor 21 is thereby continuously rotated until the peak portion 23a of the cam 23 engages the pin 36 to swing.
  • the lever 35 in the clockwise direction as viewed in FIG. 2.
  • the movement of the lever 35 and the pawl 37 against the ratchet wheel 19 causes the third drum 15 to be rotated to the clockwise direction as viewed in FIG. 2 by one tooth of the ratchet wheel 19 to display that the time has been changed.
  • the lever 39 rotates to the clockwise direction as viewed in FIG. 3 against the spring force of the spring 41.
  • the magnet 38 is again spaced apart from the reed switch 22 to put the latter in its OFF-state.
  • the transistor 50 is turned OFF to stop the rotation of the motor 21.
  • the third drum 1-5 for displaying the figure of minutes is intermittently driven by 1/10 rotation per one minute by the operation of the pawl 37 with the ratchet wheel 19.
  • the pulse width of the pulse applied to the transistor 50 may be a time period within which the reed switch 22 is made ON, for example, abour I second.
  • the transistor 50 is kept in its ON-state by the switch 22 after it is turned ON by the pulse and the DC motor 21 is kept rotating during the time period within which the magnet 38 approaches the switch 22.
  • the DC motor 21 is required to be rotated during this time period so as to advance the time display byone minute, it is enough that the motor 21 is rotated for only a short time period, for example, about 3 to 6 seconds every 1 minute. Accordingly, it will be easily understood that the electric clock of the present inventio'nconsumes a very small amount of electric power.
  • the means for making the third drum 15 to be 0" consists of a cam provided on one side of the ratchet wheel 19 and a pin 62 supported in the frame 10.
  • the pin 62 is biased away from the cam 60 by a coil spring 63, but when the pin 62 is manually pushed against the coil spring 63, the tip end of the pin 62 contacts the cam 60 at a straight portion of its side surface to forcibly reset the third drum 15 to be 0.
  • Such reset means are well known in the art and another type of such means could be employed without derogating from the invention.
  • the reset signal is applied to the reset terminal 57a of the divider or counter 57 to reset the contents thereof.
  • the time display is reset and at the same time the counter 57 is also reset to carry out the time display correction with a time period on the order of a second. It is assumed that when the counter 57 counts, for example, 35, the drum is reset to be 0. If no provision were made for simultaneously resetting the counter 57 at the same time, then since the counter 57 may start to count the pulses from the divider 57 from35, the motor 21 might be driven when the counter 57 counts 60" to display 1 on the drum 15. In other words, this would result in the error of 25 seconds in the time display. In the invention, however, since the counter 57 is reset at the same time as the drum 15 is reset to 0, such an error mentioned just above is avoided.
  • the third drum 15 is only reset, but in the other embodiments the first and second drums l3 and 14 are reset at the same time to be 0, respectively. In such embodiments, the first divider 56 may be reset simultaneously.
  • time dis-. play may include lesser or greater divisions of time such as days and months, by way of example only.
  • An improved electric clock of the type having a motor with a drive shaft, a self-contained electric power source and time display means, wherein the improvement comprises:
  • a. semiconductor switching means connected to the power source and the motor for intermittently energizing the motor at periodic intervals of time, the semiconductor switching means having a control electrode supplied with pulses,
  • a circuit including at least an on/off reed switch connected to said control electrode for controlling the semiconductor switching means
  • d. means for driving the time display means so as to advance the time display means by one unit of time in response to the rotation of the motor drive shaft.
  • an electric clock as recited in claim 1 wherein the means for driving the time display means include reduction gear means and a cam which is rotated with the rotation of the motor drive shaft through the reduction gear means and a lever engaged with the cam and having a pawl, a ratchet wheel mounted on the time display means and rotated with the rotation of the cam through the pawl of the lever.
  • time display means include a plurality of drums arranged in a predetermined sequence, each drum having numerals for time display, and gear means, each provided between adjacent ones of the drums for intermittently transmitting the rotation from one drum to the next adjacent drum, in sequence, the ratchet wheel being provided on one of the end drums.
  • the on/off switch is magnetically sensitive
  • the means for opening and closing the on/off switch includes a magnet and means for supporting the magnet for movement toward and away from the on/off switch to open and close it in response to rotation of the motor drive shaft, means for maintaining the magnet near the on/off switch for continuously closing the same during the rotation of the motor drive shaft, and wherein the means for driving the time display means are mechanically connected to the means for maintaining the magnet near the on/off switch.
  • the semiconductor switching means include a transistor, and the on/off reed switch and the power source being connected in series between the base-emitter electrodes of the transistor, and the power source and the motor being connected in series between the emittercollector electrodes of the transistor.
  • An electric clock as recited in claim 1. further comprising a stabilized oscillator and frequency dividing means for dividing the frequency of a signal generated by the oscillator, the output from the frequency dividing means being applied to the semiconductor switching means so that the time display means are driven by the motor which is intermittently energized.
  • time display means include a moving body which has thereon the numerals of 0" to 9" for displaying at least the figure of minutes, the moving body having zero reset means.
  • the frequency dividing means include a divider for frequency-converting the signal from the oscillator to that with the frequency of 1 Hz and a counter of scale of 60 for counting the signal of 1 Hz to 60 and then producing one pulse which is fed to the control electrode of the semiconductor switching means, the counter of scale of 60 having a terminal which is ganged with the zero reset means of the time display means to zeroreset the counter contents to be zero.
  • switching means for intermittently supplying power to said motor from said electric power source
  • c. means for maintaining the actuation of said switching means for a predetermined duration of rotation 12.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electromechanical Clocks (AREA)
  • Stopping Of Electric Motors (AREA)
  • Permanent Magnet Type Synchronous Machine (AREA)
US00333875A 1972-02-26 1973-02-20 Electric clock Expired - Lifetime US3808791A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1972023729U JPS48100170U (enrdf_load_stackoverflow) 1972-02-26 1972-02-26

Publications (1)

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US3808791A true US3808791A (en) 1974-05-07

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US00333875A Expired - Lifetime US3808791A (en) 1972-02-26 1973-02-20 Electric clock

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US (1) US3808791A (enrdf_load_stackoverflow)
JP (1) JPS48100170U (enrdf_load_stackoverflow)
CA (1) CA968167A (enrdf_load_stackoverflow)
GB (1) GB1397667A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3971204A (en) * 1974-01-17 1976-07-27 Norio Kawaguchi Circuit for driving a DC motor for a clock
EP0985986A1 (en) * 1998-08-07 2000-03-15 Richard Wang World clock with synchronous display

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3134220A (en) * 1961-05-16 1964-05-26 Dichl Electric clock
US3451210A (en) * 1966-07-01 1969-06-24 Benrus Corp System for maintaining oscillations in an electric timing mechanism having an oscillatory element
US3568430A (en) * 1968-07-11 1971-03-09 Hamilton Watch Co Resistance bridge controlled timekeeping device
US3601975A (en) * 1969-04-23 1971-08-31 Timex Corp Horological movement utilizing a radioactivity detector and source
US3643419A (en) * 1969-07-14 1972-02-22 California Inst Of Techn Apparatus for fine adjustment of signal frequency

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3134220A (en) * 1961-05-16 1964-05-26 Dichl Electric clock
US3451210A (en) * 1966-07-01 1969-06-24 Benrus Corp System for maintaining oscillations in an electric timing mechanism having an oscillatory element
US3568430A (en) * 1968-07-11 1971-03-09 Hamilton Watch Co Resistance bridge controlled timekeeping device
US3601975A (en) * 1969-04-23 1971-08-31 Timex Corp Horological movement utilizing a radioactivity detector and source
US3643419A (en) * 1969-07-14 1972-02-22 California Inst Of Techn Apparatus for fine adjustment of signal frequency

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3971204A (en) * 1974-01-17 1976-07-27 Norio Kawaguchi Circuit for driving a DC motor for a clock
EP0985986A1 (en) * 1998-08-07 2000-03-15 Richard Wang World clock with synchronous display

Also Published As

Publication number Publication date
JPS48100170U (enrdf_load_stackoverflow) 1973-11-26
GB1397667A (en) 1975-06-18
CA968167A (en) 1975-05-27

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