US3577725A - Sound generator for alarm clocks - Google Patents

Sound generator for alarm clocks Download PDF

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Publication number
US3577725A
US3577725A US840238A US3577725DA US3577725A US 3577725 A US3577725 A US 3577725A US 840238 A US840238 A US 840238A US 3577725D A US3577725D A US 3577725DA US 3577725 A US3577725 A US 3577725A
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Prior art keywords
circuit
sound generator
oscillator
recited
mechanical oscillator
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Expired - Lifetime
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US840238A
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English (en)
Inventor
Wolfgang Ganter
Georg Kunz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gebrueder Junghans GmbH
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Gebrueder Junghans GmbH
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Publication date
Application filed by Gebrueder Junghans GmbH filed Critical Gebrueder Junghans GmbH
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    • G—PHYSICS
    • G04—HOROLOGY
    • G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C21/00—Producing acoustic time signals by electrical means
    • G04C21/02—Constructional details
    • G—PHYSICS
    • G04—HOROLOGY
    • G04C—ELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C21/00—Producing acoustic time signals by electrical means
    • G04C21/16—Producing acoustic time signals by electrical means producing the signals at adjustable fixed times
    • G04C21/20—Producing acoustic time signals by electrical means producing the signals at adjustable fixed times by closing a contact to ring an electromechanical alarm
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K9/00—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers
    • G10K9/12—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated
    • G10K9/13—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated using electromagnetic driving means

Definitions

  • a sound generator for an alarm clock including a mechanical oscillator driven by a transistor circuit.
  • the transistor circuit includes a drive coil on the output and a control coil on the input.
  • the drive coil excites a mechanical oscillator which in turn varies the reluctance of the control coil.
  • the drive and control coils are magnetically coupled together so that the circuit operates initially as a conventional blocking oscillator whose frequency depends upon the values of the circuit elements. Once the mechanical oscillator begins to move, however, the control coil reluctance is affected so as to convert the operation of the circuit into an amplifying cirfrequency.
  • the invention relates to a sound generator for alarm clocks. comprising a mechanical oscillator and a transistor circuit which produces drive pulses for the oscillator and is capable of operating as a blocking oscillator circuit.
  • the input section of the transistor circuit is provided with a control coil series-connected to a capacitor whereas the output section is provided with a drive coil.
  • the circuit is furthermore provided with a resistor which connects a battery terminal to the control electrode; the coils being acted upon by a premagnetized magnetic circuit, the reluctance of which is affected by the movement of the mechanical oscillator.
  • a bell which is operated without contact, by electromagnetic means, and the hammer of which is actuated by a coil provided in the output section of a transistor.
  • a control coil magnetically coupled with the coil that actuates the hammer is provided in the input section of the transistor.
  • the transistor circuit acts as feedback circuit, so that in the output section drive pulses occur, the frequency of which is affected by the of ferromagnetic material which moves within the coils, so that the hammer oscillates at its natural frequency.
  • the employment of such a circuit however involves the risk that the feedback oscillations start only slowly or not at all, for instance if the voltage of the battery has dropped.
  • power consumption is relatively high since the frequency of the feedback oscillator is not necessarily the same as the natural oscillation frequency of the hammer.
  • a sound generator of the initially mentioned kind with a blocking oscillator transistor circuit wherein the circuit elements on which the pulse train frequency of the blocking oscillator depends are of such value that the pulse train frequency of the blocking oscillator device equals approximately the natural frequency of the diaphragm.
  • the invention aims at the construction of a sound generator of the initially mentioned kink which is of simple structure, responds quickly and operates efficiently. According to the invention this is accomplished by giving the elements of the transistor circuit and the magnetic circuit such values that the transistor circuit operates, when the oscillator is at rest, as a blocking oscillator circuit. When the mechanical oscillator oscillates at normal amplitude the transistor circuit operates as an amplifier circuit controlled by the oscillator.
  • the magnetic circuit may consist of two parallel cores of ferromagnetic material unilaterally connected to each other by a yoke, in which structure a leaf spring with a magnetic armature is arranged in front of the free ends of the cores to act as the mechanical oscillator.
  • a permanent-magnet strip magnetized in the direction of the core axis may be mounted onto the front surface of the core which supports the control coil.
  • the cores that support the coils may be connected to a plate of insulating material on which the electric circuit elements are mounted.
  • the insulating material is preferably provided with a printed circuit.
  • the ends of the cores, connected to each other by a yoke, may be provided with fastening bolts projecting through the yoke.
  • Contact springs are suitably provided in the clock case so as to supply current and to rest with their free ends upon conductive areas of the printed circuit.
  • one line for feeding current to the sound generator passes via the drive circuit for the movement-regulating oscillator.
  • the contact. actuated by the clockwork. for releasing the sound generator is arranged on a plate on which the clockwork driving circuit is mounted.
  • the plate that supports the clockwork-driving circuit may be connected via a cable provided with a plug to a circuit-feeding contact spring for the sound generator.
  • FIG. 1 a side view of the sound generator of the invention, partly in Cross section;
  • FIG. 2 a circuit diagram of the drive circuit for the sound generator
  • FIG. 3 a rear view of an alarm clock with the sound generator of the invention
  • FIG. 4 an illustration of the electric drive circuit for the movement-regulating oscillator of the alarm clock
  • FIG. 5 a section along line V-V in FIG. 3;
  • FIG. 6 a view of the sound generator according to FIG. 1, from the bottom.
  • the sound generator contains two cores l0 and 11 of ferromagnetic material unilaterally connected to each other by a yoke 12 which likewise consists of ferromagnetic material. Cores 10 and 11 are provided with projections 10a and 11a by means of which they are riveted to yoke 12. Cores 10 and 11 support a plate 19 of insulating material provided with a printed circuit (cf. FIG. 6) which in turn supports the elements of the drive circuit of the sound generator.
  • Coils 17 and 18, of which coil 17 is arranged in the input section and coil 18 in the output section of transistor 20, are mounted on cores 10 and 11 (FIG. 2).
  • a permanent-magnet strip 16 is mounted on the free end surface of core 10, which strip is magnetized in the direction of the longitudinal axis of core 10.
  • Yoke 12 is provided with a bent arm 12a to which a leaf spring 13 is fastened.
  • This leaf spring 13 is bent off at a right angle and supports an armature 14 which is located in front of the free ends of cores 10 and Il.
  • Armature 14 consists likewise of ferromagnetic material.
  • armature I4 is provided with a rivet of nonmagnetic material which prevents the armature from adhering to core 11.
  • Ends 10b and 11b of cores 10 and 11 are provided with a threading. They serve for fastening the sound generator in the clock case 30 (FIG. 5).
  • a capacitor 21 is seriesconnected to coil 17, and the base electrode of transistor 20 is connected via a resistor 22 to the positive terminal of a DC voltage source 23.
  • Numeral 24 (FIG. 2) indicates the contact actuated by the clockwork.
  • the circuit operates as follows:
  • Capacitor 2 1 is charged by these pulses so that, when a specified oscillation amplitude is reached by the mechanical oscillator, transistor 20 is given a bias voltage, whereby its point of operation is shifted and the circuit operates no longer as blocking oscillator.
  • transistor operates then solely as an amplifier, controlled by pulses induced in coil 17 and furnishing at the output side correspondingly amplified pulses.
  • the frequency of the pulses passing through drive coil 18 correspond exactly to the natural frequency of the mechanical oscillator.
  • FIG. 3 shows the arrangement of the sound generator within an alarm clock case 30.
  • Numeral 23 indicates a feeding battery which is lodged in a chamber separated by an intermediate wall a.
  • An aperture 30b for battery 23 is provided at the bottom of clock case 30. This aperture 30b can be shut by a contact plate 32 which is in friction contact with a stationary slide plate 34.
  • Numeral 33 indicates a rivet that holds contact plate 32 in place and serves also as handle for shifting contact plate 32.
  • Contact plate 34 is provided with two bent-off resilient strips 34a and 34b.
  • Contact spring 34a rests against a contact element 38a of the drive circuit for the movement-regulating oscillator of the alarm clock mechanism (FIG. 4).
  • the circuit is supported by a plate 38 of insulating material, fastened to clockwork 36.
  • the clockwork is connected via a screw 37 to a conductive section 38b of the drive circuit.
  • an electrically conductive plate provided with an arm 35b is inserted in clock case 30.
  • the arm 35b is conductively connected to clockwork 36.
  • Plate 35 contains also a resilient arm 35a which in turn is connected to battery 23.
  • a spring 24 is mounted on plate 35, which spring is movable by means of a cam 31 actuated by the clockwork.
  • a countercontact 25 connected to a conductive section 380 of the printed circuit (FIG. 4) is coordinated with spring 24.
  • a cable 26, provided on its free end with a terminal plug 27, is connected to conductive element 38c. This terminal plug 27 can be connected to a conductive spring arm 28, the bent-off end 28a of which rests against a conductive section 1% (FIG. 6) of the printed circuit of the sound generator.
  • the second current supply to the sound generator takes place via a contact spring 34b which abuts against a conductive element 19a of the printed circuit of the sound generator,
  • An arm 40a of a switch-off key 40 is provided in the area of arm 28a.
  • the said arm 40a lifts, in one terminal position of key 40, arm 28a from the conductive area 19b of the printed circuit, so that the current supply remains interrupted, independently of contact 24, 25 which is actuated by the clockwork.
  • the structure of the sound generator and its arrangement within the clockwork are simple.
  • the current supply is also assured at lowest expenditure.
  • a sound generator for alarm clocks comprising: a mechanical oscillator and a transistor circuit which produces drive pulses for the oscillator and is capable of operating as blocking oscillator circuit, said transistor circuit being provided in the input section with a control coil series-connected to a capacitor.
  • said magnetic circuit comprises two parallel cores of ferromagnetic material unilaterally connected to each other by a yoke and said mechanical oscillator comprises a leaf spring with a magnetic armature arranged in front of the free ends of said cores.
  • the sound generator recited in claim 2 further comprising a permanent-magnet strip magnetized in the direction of the core axis and mounted on the front surface of the core which supports said control coil 4.
  • the sound generator recited in claim 2 wherein said cores which support said coils are connected to an insulating plate on which the electric circuit elements are mounted.
  • the sound generator recited in claim 8 further comprising a switch-off key having an arm which, in one terminal position of the key, lifts one of said contact springs from the printed circuit.
  • the sound generator recited in claim 2 further comprising a current supply line passing to the sound generator via the drive circuit for the movement-regulating oscillator and a contact actuated by the clockwork for the release of the sound generator, said contact being mounted on a plate on which the clockwork drive circuit is mounted.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Electromechanical Clocks (AREA)
  • Apparatuses For Generation Of Mechanical Vibrations (AREA)
US840238A 1968-07-10 1969-07-09 Sound generator for alarm clocks Expired - Lifetime US3577725A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE1773812 1968-07-10

Publications (1)

Publication Number Publication Date
US3577725A true US3577725A (en) 1971-05-04

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ID=5701876

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US840238A Expired - Lifetime US3577725A (en) 1968-07-10 1969-07-09 Sound generator for alarm clocks

Country Status (3)

Country Link
US (1) US3577725A (enrdf_load_stackoverflow)
CH (2) CH948269A4 (enrdf_load_stackoverflow)
FR (1) FR2012660A1 (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3824789A (en) * 1972-02-18 1974-07-23 Muller Schlenker Battery-operated miniature alarm clock
US3950744A (en) * 1974-06-14 1976-04-13 Projects Unlimited, Inc. Modular buzzer with diaphragm molded into housing
JPS5167761U (enrdf_load_stackoverflow) * 1974-11-25 1976-05-28
US4004408A (en) * 1973-04-03 1977-01-25 Kienzle Uhrenfabriken Gmbh Mechanical improvement on an electric alarm clock
US4276625A (en) * 1978-04-22 1981-06-30 Kundo - Kieninger + Obergfell Bell-striking clock

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE26817E (en) * 1967-12-06 1970-03-10 Patrick transistor alarm clock

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE26817E (en) * 1967-12-06 1970-03-10 Patrick transistor alarm clock

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3824789A (en) * 1972-02-18 1974-07-23 Muller Schlenker Battery-operated miniature alarm clock
US4004408A (en) * 1973-04-03 1977-01-25 Kienzle Uhrenfabriken Gmbh Mechanical improvement on an electric alarm clock
US3950744A (en) * 1974-06-14 1976-04-13 Projects Unlimited, Inc. Modular buzzer with diaphragm molded into housing
JPS5167761U (enrdf_load_stackoverflow) * 1974-11-25 1976-05-28
US4276625A (en) * 1978-04-22 1981-06-30 Kundo - Kieninger + Obergfell Bell-striking clock

Also Published As

Publication number Publication date
CH948269A4 (enrdf_load_stackoverflow) 1971-07-30
CH516839A (de) 1971-07-30
FR2012660A1 (enrdf_load_stackoverflow) 1970-03-20

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