US4257036A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tone generator
Assignee: Lectron Products Inc
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Filing: 1979-11-27
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Granted: 1981-03-17
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Expires: 1999-11-27
Abstract
Abstract A tone generator for producing an audible sound for a predetermined time period in response to the occurrence of one or more predetermined conditions. The tone generator comprises a diaphragm mounted within a resonant sound cavity that is activated by an electromagnetic assembly which is in turn driven by the output signal from an oscillator circuit. The control logic and timing circuit for the tone generator includes a unique PTC subassembly that provides a timed logic signal for controlling the activations of the diaphragm, as well as an independently generated signal for contemporaneously activating a lamp which provides a visual indication of the detected predetermined condition. The control logic and timing circuit is adapted to produce the proper timed logic signal despite the absence of a lamp in the circuit or a lamp failure.
Inventors
- 👤 Michael Slavin
- 👤 Juhan Telmet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:42
CPC Classifications
G; G08; G08B; G08B3/00; G08B3/10; G10; G10K; G10K9/00; G10K9/12; G10K9/13; H; H04; H04R; H04R13/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
245 words
A tone generator adapted for use with an automotive vehicle or the like and to generate a timed audible signal in conjunction with a visual signal by a lamp on the vehicle, said tone generator comprising a diaphragm; an electromagnetic coil for causing said diaphragm to vibrate by means of cyclic energization of said coil; an oscillator for cyclically energizing said electromagnetic coil; and a control circuit including timing means for controlling the enabling of said oscillator and the energization of said lamp; said timing means including a positive temperature coefficient resistance element comprising a body of PTC material having an anomaly temperature, said body having electrically conductive contact surface layers on first and second discrete surfaces thereof, said first conductive surface layer defining first, second and third discrete contact areas, said contact areas being electrically isolated from each other and forming a plurality of PTC resistor means with respect to said second conductive surface layer, said contact areas being apportioned and disposed so that said first and second contact areas are larger than said third contact area and said second contact area is disposed between said first and third contact areas, said first contact area being connected across an electrical source, said second contact area adapted to be connected between said electrical source and said lamp for controlling the energization of said lamp, and said third contact area being connected between said electrical source and said oscillator for controlling the enabling of said oscillator.
Claim 2
Dependent Claim
245 words
A tone generator adapted for use with an automotive vehicle or the like and to generate a timed audible signal in conjunction with a visual signal by a lamp on the vehicle, said tone generator comprising a diaphragm; an electromagnetic coil for causing said diaphragm to vibrate by means of cyclic energization of said coil; an oscillator for cyclically energizing said electromagnetic coil; and a control circuit including timing means for controlling the enabling of said oscillator and the energization of said lamp; said timing means including a positive temperature coefficient resistance element comprising a body of PTC material having an anomaly temperature, said body having electrically conductive contact surface layers on first and second discrete surfaces thereof, said first conductive surface layer defining first, second and third discrete contact areas, said contact areas being electrically isolated from each other and forming a plurality of PTC resistor means with respect to said second conductive surface layer, said contact areas being apportioned and disposed so that said first and second contact areas are larger than said third contact area and said second contact area is disposed between said first and third contact areas, said first contact area being connected across an electrical source, said second contact area adapted to be connected between said electrical source and said lamp for controlling the energization of said lamp, and said third contact area being connected between said electrical source and said oscillator for controlling the enabling of said oscillator.
Claim 3
Dependent Claim
38 words
The tone generator of claim 1 wherein said PTC resistor means are operative in use to heat said PTC element above its anomaly temperature within a predetermined time interval after application of electrical power to said PTC element.
Claim 4
Dependent Claim
14 words
The tone generator of claim 2 wherein said predetermined time interval is 4-8 seconds.
Claim 5
Dependent Claim
52 words
The tone generator of claim 1 further including a resistor connected between said third PTC contact area and ground so that said third PTC contact area comprises the top half of a voltage divider and said oscillator is enabled in accordance with the signal produced at the midpoint of said voltage divider.
Claim 6
Dependent Claim
28 words
The tone generator of claim 1 wherein said first, second and third contact areas of said PTC element are defined by voids in said first conductive surface layer.
Claim 7
Dependent Claim
19 words
The tone generator of claim 5 wherein said first contact area comprises substantially half of said first surface layer.
Claim 8
Dependent Claim
27 words
The tone generator of claim 6 including leads electrically connected to each of said first, second and third contact areas and to said second conductive surface layer.
Claim 9
Dependent Claim
102 words
The tone generator of claim 1 further including retainer means for securing said diaphragm in position; said retainer means including a gasket member disposed on the peripheral marginal portion of said diaphragm and comprised of a flexible and resilient material that permits relatively slow air leaks to and from said closed sound cavity past the periphery of said diaphragm to allow the steady-state pressure differential across said diaphragm to equalize and that provides an effective seal at the periphery of said diaphragm with respect to rapid air movements created within said closed sound cavity due to vibration of said diaphragm in use.
Claim 10
Dependent Claim
31 words
The tone generator of claim 8 further including a casing fastened to said cover and forming a secondary sound cavity at the side of said diaphragm opposite said closed sound cavity.
Claim 11
Dependent Claim
38 words
The tone generator of claim 9 wherein said casing is ported so as to make said secondary sound cavity an open sound cavity, the effective ported area being determined in accordance with the primary frequency of said oscillator.
References Cited (Backward Citations)
US3944970A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-16 | 1984-09-15 | 1985-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-16 | 1988-09-15 | 1989-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-16 | 1992-09-15 | 1993-03-17 | $7700.00 | Window Closed / Lapsed |