US3844646A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Projection apparatus
Assignee: Individual
•
Filing: 1973-06-26
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Granted: 1974-10-29
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Expires: 1993-06-26
Abstract
Abstract A device for projecting diapositives or transparent slides in cross fade. The device is associated with two projectors each comprising a projection lamp, a magazine containing diapositives, and mechanism for automatically advancing the magazine and the diapositives. Provision is made for separate or simultaneous control of the illumination of the lamps and of the respective advancing mechanisms. The device includes a generator of first and second command signals having first and second variable frequencies in distinct first and second ranges. The device also includes a decoding unit having an input connected to the output of the generator and which provides command signals for controlling respectively the illumination of the lamps and the advancement of the magazines. The decoding unit comprises two channels each associated with a projector, each channel comprising successively a selective amplifier, a converter of the voltage-frequency type and a power stage. The output of the power stage is connected to one of the lamps. The decoding unit also comprises two relays for detecting interruption of the command signals from the selective amplifiers and correlatively controlling the advancing mechanisms.
Inventors
- 👤 C Oury
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:25
CPC Classifications
G; G03; G03B; G03B23/00; G03B23/18
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
202 words
A device for projecting diapositives in cross fade, in combination with two projectors each comprising a projection lamp, a diapositives magazine, and automatic means for advancing the magazine and the diapositives, said device comprising a generator of first and second signals having first and second variable frequencies in distinct first and second ranges, and a decoding unit having an input connected to the output of the generator of said first and second signals and which provides further signals for controlling respectively the luminous intensity of the projector lamps and the advancement of the magazines of these projectors, said decoding unit comprising first and second parallel channels associated respectively with the first and second projectors and each comprising successively a selective amplifier, a converter of the frequency-voltage type, and a power stage, the power stage having an input to which there is applied the output voltage from said converter and an output connected to the associated projector lamp, said decoding unit also comprising means for interrupting the output from each of the selective amplifiers and means for detecting the interruption of each of the outputs from the selective amplifiers and for correlatively controlling the advancement means for the magazines of the two projectors.
Claim 2
Independent Claim
202 words
A device for projecting diapositives in cross fade, in combination with two projectors each comprising a projection lamp, a diapositives magazine, and automatic means for advancing the magazine and the diapositives, said device comprising a generator of first and second signals having first and second variable frequencies in distinct first and second ranges, and a decoding unit having an input connected to the output of the generator of said first and second signals and which provides further signals for controlling respectively the luminous intensity of the projector lamps and the advancement of the magazines of these projectors, said decoding unit comprising first and second parallel channels associated respectively with the first and second projectors and each comprising successively a selective amplifier, a converter of the frequency-voltage type, and a power stage, the power stage having an input to which there is applied the output voltage from said converter and an output connected to the associated projector lamp, said decoding unit also comprising means for interrupting the output from each of the selective amplifiers and means for detecting the interruption of each of the outputs from the selective amplifiers and for correlatively controlling the advancement means for the magazines of the two projectors.
Claim 3
Dependent Claim
75 words
The combination claimed in claim 1, in which said generator comprises first and second variable frequency oscillators having outputs respectively supplying said first and second signals, first and second manually-operated adjusting means to cause selective variations in the frequencies of said first and second oscillators, and a mixer comprising first and second inputs connected respectively to the outputs of the first and second oscillators, and an output connected to the input of the decoding unit.
Claim 4
Dependent Claim
30 words
The combination claimed in claim 2, in which said adjusting means for adjusting the oscillators comprise first and second levers and potentiometers, cursors of said potentiometers coupled to said levers.
Claim 5
Dependent Claim
67 words
The combination claimed in claim 2, comprising first and second manually-operated push-buttons, and first and second break contacts actuated respectively by the first and second push-buttons and connected respectively in series between the output from the first oscillator and the first input to the mixer on the one hand, and the output from the second oscillator and the second input to the mixer on the other hand.
Claim 6
Dependent Claim
56 words
The combination claimed in claim 4, comprising a third constant-frequency oscillator having an output supplying a control signal, a third input to the mixer, and first and second make contacts actuated respectively by the first and second push-buttons and connected in series between the output from the third oscillator and the third input to the mixer.
Claim 7
Dependent Claim
105 words
The combination claimed in claim 5, in which said decoding unit comprises a third control amplifier having an input connected to the output of the mixer, and in which said means detecting the interruption of the outputs from the selective amplifiers comprise first and second relays, each of said first and second relays having a first input connected to one output of the associated control amplifier and a second input connected to the output of the associated selective amplifier, whereby to switch over when a signal from first or second variable frequency oscillators is interrupted in the presence of a signal from the control amplifier.
Claim 8
Dependent Claim
22 words
The combination claimed in claim 1, in which said generator of first and second variable frequency signals is a magnetic tape recorder.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-28 | 1978-04-29 | 1978-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-28 | 1982-04-29 | 1982-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-28 | 1986-04-29 | 1986-10-29 | $7700.00 | Window Closed / Lapsed |