US3920906A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wired broadcasting systems
Assignee: Communications Patents Ltd
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Filing: 1974-07-02
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Granted: 1975-11-18
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Expires: 1994-07-02
Abstract
Abstract In a wired broadcasting system the switching means for selecting one of a plurality of program sources is a set of electromagnetic relay switches each having two operating coils connected into different switching circuits. Switching is accomplished from a train of pulses actuating thyrister circuits to operate selected sets of coils. In one embodiment three wires provide selection signals to three different relays having a common second winding circuit and energization of two coils on each relay is necessary to operate a selection switch set. By choice of sets of pulses by a dialing mechanism to energize two circuits having the different wiring patterns through the coils one of nine relays may be operated for a selection. The dial pulsing mechanism is operated twice to select one program defining one set of three relays and one of those three respectively.
Inventors
- 👤 Eric John Gargini
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:09
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/173; H04N7/17345; H04N7/17354; H04N2007/1739
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
204 words
A wired broadcasting system comprising a plurality of programme signal sources, switch means for connecting a subscriber to a desired one of said programme signal sources and a signal cable extending between said switch means and said subscriber, said switch means comprising a plurality of electromagnetically operable contacts, the electro-magnets comprising a plurality of coils, means for connecting said coils in groups such that each of the plurality of coils of an electro-magnet is connected in a separate group and means for controlling the flow of electric current through selected groups of coils thereby to actuate that contact associated with that electro-magnet the coils of which are included in the selected groups wherein the means for controlling the flow of electric current comprises thyristor semi-conductor devices arranged to control passage of current by application thereto by a train of pulses, wherein the thyristors associated with one group of coils are arranged to operate in sequence in response to pulses applied to them over one control line in the subscriber''s signal cable and the thyristors associated with the other group of coils are arranged to operate in sequence in response to pulses applied to them over a further control line in a subscriber''s signal cable.
Claim 2
Dependent Claim
204 words
A wired broadcasting system comprising a plurality of programme signal sources, switch means for connecting a subscriber to a desired one of said programme signal sources and a signal cable extending between said switch means and said subscriber, said switch means comprising a plurality of electromagnetically operable contacts, the electro-magnets comprising a plurality of coils, means for connecting said coils in groups such that each of the plurality of coils of an electro-magnet is connected in a separate group and means for controlling the flow of electric current through selected groups of coils thereby to actuate that contact associated with that electro-magnet the coils of which are included in the selected groups wherein the means for controlling the flow of electric current comprises thyristor semi-conductor devices arranged to control passage of current by application thereto by a train of pulses, wherein the thyristors associated with one group of coils are arranged to operate in sequence in response to pulses applied to them over one control line in the subscriber''s signal cable and the thyristors associated with the other group of coils are arranged to operate in sequence in response to pulses applied to them over a further control line in a subscriber''s signal cable.
Claim 3
Dependent Claim
24 words
A system as claimed in claim 1, wherein the pulses are applied between said one or said further control line and a return conductor.
Claim 4
Dependent Claim
28 words
A system as claimed in claim 2, wherein the return conductor is formed by a phantom connection on a pair of signal conductors in the subscriber''s signal cable.
Claim 5
Dependent Claim
37 words
A system as claimed in claim 3, wherein at the subscriber''s terminal equipment means are provided for disconnecting the return conductor thereby to interrupt any current flow through the thyristors and thus de-energise all electro-magnets associated therewith.
Claim 6
Dependent Claim
34 words
A system as claimed in claim 4, wherein means are provided whereby upon connection of the return conductor to the subscriber''s terminal equipment operating potential is arranged to be applied slowly to the thyristors.
Claim 7
Dependent Claim
23 words
A system as claimed in claim 5, wherein thE operating potential is arranged to be applied to the thyristors through a resistor/capacitor network.
Claim 8
Dependent Claim
51 words
A system as claimed in claim 1, wherein each thyristor has a capacitor associated with the gate electrode thereof and the control pulses applied over the control lines cause a charge to be transferred successively from one capacitor to the next in oreder to control the current flow through said thyristors.
Claim 9
Dependent Claim
20 words
A system as claimed in claim 1, wherein the pulses are arranged to be generated by a telephone dial mechanism.
Claim 10
Dependent Claim
52 words
A system as claimed in claim 8, wherein said telephone dial mechanism is connected to one control line and wherein upon completion of an initial dialling operation the off-normal contacts of the telephone dial are arranged to cause connection of the other control line to said dial during a subsequent dialling operation.
Claim 11
Dependent Claim
38 words
A system as claimed in claim 9, wherein the connection to said one or other control line to the telephone dial is controlled by a slugged change-over relay the energisation of which is controlled by the off-normal contacts.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-11-17 | 1979-05-19 | 1979-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-17 | 1983-05-19 | 1983-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-17 | 1987-05-19 | 1987-11-18 | $7700.00 | Window Closed / Lapsed |