Patent US3932718A successfully refreshed from Google Patents.
US3932718A
Expired / Lapsed
US
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Intrusion detector
Assignee: Individual
•
Filing: 1974-07-01
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Granted: 1976-01-13
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Expires: 1994-07-01
Abstract
Abstract An intrusion detector comprises a housing attachable to a fixed support, an electrical switch fixed within the housing and having a switch actuator movable within a longitudinal bore in the housing to actuate the switch. The actuator is attachable to a wire tensioned between it and another fixed support so as to actuate the switch upon stretching or cutting the wire, a spring being disposed within the housing bore and having one end engaging the movable actuator to bias it in the direction opposite to the tensioned wire. A closure member closes one end of the bore and engages the opposite end of the spring and is adjustable to preset the initial non-actuating position of the actuator with respect to the switch.
Inventors
- 👤 Chaim Porat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 11:47
CPC Classifications
G; G08; G08B; G08B13/00; G08B13/02; G08B13/12; G08B13/126; G08B13/122; H; H01; H01H; H01H36/00; H01H36/0006; H01H36/0046
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
133 words
An intrusion detector comprising a housing attachable to a fixed support; an electrical switch fixed within the housing; said housing being formed with a longitudinal bore extending at least partly therethrough; a switch actuator movable within the longitudinal bore to actuate the switch; said actuator being attachable to a wire tensioned between the movable actuator and another fixed support so as to actuate the switch upon stretching or cutting the wire; a spring disposed within the bore in the housing, one end of the spring engageing said movable actuator to bias same in the direction opposite to said tensioned wire; and an adjustable closure member closing one end of said bore and engaging the opposite end of the spring to preset the initial non-actuating position of the actuator with respect to said switch.
Claim 2
Dependent Claim
133 words
An intrusion detector comprising a housing attachable to a fixed support; an electrical switch fixed within the housing; said housing being formed with a longitudinal bore extending at least partly therethrough; a switch actuator movable within the longitudinal bore to actuate the switch; said actuator being attachable to a wire tensioned between the movable actuator and another fixed support so as to actuate the switch upon stretching or cutting the wire; a spring disposed within the bore in the housing, one end of the spring engageing said movable actuator to bias same in the direction opposite to said tensioned wire; and an adjustable closure member closing one end of said bore and engaging the opposite end of the spring to preset the initial non-actuating position of the actuator with respect to said switch.
Claim 3
Dependent Claim
122 words
An intrusion detector according to claim 1, wherein the switch actuator is attachable to a stretched wire exposed to temperature and wind conditions and is tensioned between two fixed supports, the stretchability of the two spans of wire between said two fixed supports and the actuator being substantially equal to each other so that the switch is actuated only upon the differential tensioning of the two wire spans such as caused by pulling or cutting the wire and is not actuated upon the equal and opposite tensioning of the two wire spans such as caused by temperature changes or the wind, and wherein said housing includes a pair of said springs serving as balancing springs one on each side of the actuator.
Claim 4
Dependent Claim
92 words
An intrusion detector according to claim 2, wherein said switch actuator includes an arm extending through a slot in the housing and carries a wire clamp for clamping to the tensioned wire, both ends of said bore being closed by closure members, each of said balanced springs being interposed between one closure member and the respective end of the movable switch actuator, at least one of said closure members being adjustable for presetting the initial, non-actuating position of the actuator with respect to the switch, and the force required to actuate same.
Claim 5
Dependent Claim
25 words
An intrusion detector according to claim 2, wherein said two spans of tensioned wire include two balanced springs, each connected in one of said spans.
Claim 6
Dependent Claim
38 words
An intrusion detector according to claim 2, wherein said electrical switch is a reed switch, the switch actuator including a permanent magnet for actuating the switch when moved a predetermined distance by the differential tensioning of the wire.
Claim 7
Dependent Claim
36 words
An intrusion detector according to claim 5, wherein said reed switch is normally closed and is opened when the actuator is moved a predetermined distance from its initial position by the differential tensioning of the wire.
Claim 8
Dependent Claim
31 words
An intrusion detector according to claim 1, wherein said switch is a reed switch and said switch actuator includes a permanent magnet movable within the housing for actuating the reed switch.
Claim 9
Dependent Claim
128 words
An intrusion detector according to claim 7, wherein the tensioned wire is a stretchable wire exposed to temperature and wind conditions and tensioned between two fixed supports, said movable switch actuator being attached to the tensioned wire at an intermediate point thereof such that the stretchability of the span of wire between one of the wire supports and the movable switch actuator is substantially equal to that of the span of wire between the other wire support and the movable actuator, whereby the reed switch is actuated only upon the differential tensioning of the two wire spans such as caused by pulling or cutting the wire, and not upon the equal and opposite tensioning of the two wire spans such as caused by temperature changes or the wind.
Claim 10
Dependent Claim
41 words
An intrusion detector according to claim 7, wherein said tensioned wire includes only one span, one end of the wire being connected to the fixed wire support and the opposite end of the wire being connected to the movable switch actuator.
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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) | 1979-01-12 | 1979-07-14 | 1980-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-12 | 1983-07-14 | 1984-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-12 | 1987-07-14 | 1988-01-13 | $7700.00 | Window Closed / Lapsed |