Patent US4577221A successfully refreshed from Google Patents.
US4577221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power safety device for CATV tap-off unit
Assignee: Time Warner Cable Enterprises LLC
•
Filing: 1984-11-29
•
Granted: 1986-03-18
•
Expires: 2004-11-29
Abstract
Abstract In a cable television system in which one or more tap-off devices deliver television signals to an associated subscriber via drop cables connecting the tap-off devices at the subscribers' premises, and in which the tap-off devices receive electrical power from the subscribers via the drop cables, a power safety apparatus and method interrupts the application of power to the drop cable when the drop cable becomes cut, broken or disconnected to prevent individuals from receiving hazardous electrical shocks.
Inventors
- 👤 Russell A. Skinner, Sr.
- 👤 Walter S. Ciciora
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:40
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/10
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
177 words
In a cable television system having a tap-off device external to a subscriber premises, the tap-off device connected to the subscriber premises via a drop cable for delivering television signals to the subscriber premises, and the tap-off device including electronic circuitry powered at least in part by a source of subscriber-supplied electrical power which is applied to the drop cable and delivered via the drop cable to the tap-off device, a power safety device comprising: first means associated with the tap-off device and connected to the drop cable for transmitting a signal to the subscriber premises via the drop cable; second means associated with the subscriber premises for interrupting the application of power to the drop cable; and sensing means associated with the subscriber premises for sensing the transmitted signal on the drop cable, said sensing means being connected to said second means and responsive to sensing the absence of the transmitted signal for enabling said second means to interrupt the application of power to the drop cable to protect individuals from receiving a hazardous electrical shock.
Claim 2
Dependent Claim
177 words
In a cable television system having a tap-off device external to a subscriber premises, the tap-off device connected to the subscriber premises via a drop cable for delivering television signals to the subscriber premises, and the tap-off device including electronic circuitry powered at least in part by a source of subscriber-supplied electrical power which is applied to the drop cable and delivered via the drop cable to the tap-off device, a power safety device comprising: first means associated with the tap-off device and connected to the drop cable for transmitting a signal to the subscriber premises via the drop cable; second means associated with the subscriber premises for interrupting the application of power to the drop cable; and sensing means associated with the subscriber premises for sensing the transmitted signal on the drop cable, said sensing means being connected to said second means and responsive to sensing the absence of the transmitted signal for enabling said second means to interrupt the application of power to the drop cable to protect individuals from receiving a hazardous electrical shock.
Claim 3
Dependent Claim
18 words
The power safety device of claim 1, wherein the signal transmitted by said first means is substantially continuous.
Claim 4
Dependent Claim
19 words
The power safety device of claim 2, wherein the signal transmitted by said first means is a data signal.
Claim 5
Dependent Claim
72 words
The power safety device of claim 1 or claim 2 or claim 3, wherein said sensing means includes a timing means for causing said sensing means to enable said second means only if the transmitted signal is absent for a predetermined period of time, the predetermined period of time being sufficiently short such that the amount of energy applied to the drop cable during the predetermined period of time is not hazardous.
Claim 6
Dependent Claim
14 words
The power safety device of claim 1, wherein the second means includes a relay.
Claim 7
Dependent Claim
24 words
The power safety device of claim 5, wherein said relay is connected in series between the drop cable and the source of electrical power.
Claim 8
Dependent Claim
94 words
The power safety device of claim 1, further comprising: reset means associated with the subscriber premises for causing power to be applied to the drop cable to enable said first means to commence transmitting the signal; and timing means associated with said reset means for enabling said reset means to cause power to be applied to the drop cable only for a predetermined period of time, the predetermined period of time being sufficiently short such that the amount of energy applied to the drop cable during the predetermined period of time is not hazardous.
Claim 9
Dependent Claim
69 words
The power safety device of claim 1, further comprising: reset means associated with the subscriber premises for causing electrical power to be applied to the drop cable to enable said first means to commence transmitting the signal; and third means associated with said reset means for limiting the electrical power caused to be applied to the drop cable by said reset means to an amount which is not hazardous.
Claim 10
Dependent Claim
26 words
The power safety device of claim 8, wherein said third means includes means for limiting the voltage of the electrical power applied to the drop cable.
Claim 11
Dependent Claim
15 words
The power safety device of claim 7, wherein said reset means includes a switch means.
Claim 12
Dependent Claim
157 words
In a cable television system having a tap-off device external to a subscriber premises, the tap-off device connected to the subscriber premises via a drop cable for delivering television signals to the subscriber premises, and the tap-off device including electronic circuitry powered at least in part by a source of subscriber-supplied electrical power which is applied to the drop cable and delivered via the drop cable to the tap-off device, a method for protecting individuals from electrical shock in the event the drop cable is cut, broken or disconnected, comprising the steps of: transmitting a signal from the tap-off device to the subscriber premises via the drop cable; sensing the absence of the transmitted signal on the drop cable at the subscriber premises; and interrupting the application of electrical power to the drop cable at the subscriber premises in response to sensing the absence of the transmitted signal to prevent individuals from receiving a hazardous electrical shock.
Claim 13
Dependent Claim
157 words
In a cable television system having a tap-off device external to a subscriber premises, the tap-off device connected to the subscriber premises via a drop cable for delivering television signals to the subscriber premises, and the tap-off device including electronic circuitry powered at least in part by a source of subscriber-supplied electrical power which is applied to the drop cable and delivered via the drop cable to the tap-off device, a method for protecting individuals from electrical shock in the event the drop cable is cut, broken or disconnected, comprising the steps of: transmitting a signal from the tap-off device to the subscriber premises via the drop cable; sensing the absence of the transmitted signal on the drop cable at the subscriber premises; and interrupting the application of electrical power to the drop cable at the subscriber premises in response to sensing the absence of the transmitted signal to prevent individuals from receiving a hazardous electrical shock.
Claim 14
Dependent Claim
12 words
The method of claim 11, wherein the transmitted signal is substantially continous.
Claim 15
Dependent Claim
13 words
The method of claim 12, wherein the transmitted signal is a data signal.
Claim 16
Dependent Claim
74 words
The method of claim 11 or claim 12 or claim 13, further comprising: timing the absence of the transmitted signal; and enabling said interrupting step to interrupt the application of power to the drop cable only if the transmitted signal is absent for a predetermined period of time, the predetermined time being sufficiently short such that the amount of energy applied to the drop cable during the predetermined period of time is not hazardous.
Claim 17
Dependent Claim
66 words
The method of claim 11, further comprising: applying reset power to the drop cable to enable said transmitting step to commence; and terminating the appication of reset power to the drop cable after a predetermined period of time, the predetermined period of time being sufficiently short such that the amount of energy applied to the drop cable during the predetermined period of time is not hazardous.
Claim 18
Dependent Claim
38 words
The method of claim 11, further comprising: applying reset power to the drop cable to enable said transmitting step to commence; and limiting the reset power applied to the drop cable to an amount which is not hazardous.
Claim 19
Dependent Claim
25 words
The method of claim 16, wherein said limiting step includes the step of limiting the voltage of the reset power applied to the drop cable.
References Cited (Backward Citations)
US3909560A
Cited
US4135157A
Cited
US4161751A
Cited
US4205269A
Cited
JPS56152339A
Cited
US4475123A
Cited
JPS5838088A
Cited
JPS59149748A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-17 | 1989-09-16 | 1990-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-17 | 1993-09-16 | 1994-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-17 | 1997-09-16 | 1998-03-18 | $7700.00 | Window Closed / Lapsed |