Plunger-operated alarm switch assembly
First Claim
1. A tamper-resistant alarm lock switch assembly to prevent movement of a movable barrier, comprising:
- a plunger housing supporting a movable elongate plunger having a longitudinal axis and a permanent magnet having an axis that substantially coincides with the longitudinal axis of the plunger and that produces a magnetic field, the plunger being movable relative to the plunger housing along a guide path; and
a switch plate supporting a magnetically actuatable reed switch having a longitudinal axis and matable to the plunger housing to form a unitary article, the reed switch being secured to the switch plate in a predetermined relative alignment to the guide path of the plunger so that the longitudinal axis of the reed switch is substantially parallel to the longitudinal axis of the plunger, the plunger being movable between a first position in which the magnetic field and the reed switch interact to cause the reed switch to assume a first switching condition and a second position in which the magnetic field and the reed switch interact to cause the reed switch to assume a second switching condition;
the plunger and reed switch being constructed and arranged so that the reed switch assumes the first switching condition when the longitudinal axis of the plunger is transversely aligned to the longitudinal axis of the reed switch.
5 Assignments
0 Petitions
Accused Products
Abstract
A plunger-operated alarm switch assembly (10) provides without visual inspection thereof an indication of whether a barrier (14) is in a secure position or whether the alarm switch assembly has been tampered with. A preferred embodiment includes a plunger housing (18) that is matable to a switch plate (20). The plunger housing supports a movable plunger (22) having a permanent magnet (24) that produces a magnetic field (26). The switch plate supports a magnetically actuatable reed switch (28) positioned in a predetermined relative alignment to a guide path (32) of the plunger when the plunger housing and the switch plate are matably fitted together. The plunger is movable relative to the plunger housing between alarm and secure positions so that whenever the plunger is in the alarm position, the reed switch provides an alarm switching condition; whenever the plunger is in the secure position, the reed switch provides a secure switching position; and whenever the predetermined relative alignment of the reed switch and the guide path of the plunger changes, the reed switch provides the alarm switching condition.
27 Citations
18 Claims
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1. A tamper-resistant alarm lock switch assembly to prevent movement of a movable barrier, comprising:
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a plunger housing supporting a movable elongate plunger having a longitudinal axis and a permanent magnet having an axis that substantially coincides with the longitudinal axis of the plunger and that produces a magnetic field, the plunger being movable relative to the plunger housing along a guide path; and a switch plate supporting a magnetically actuatable reed switch having a longitudinal axis and matable to the plunger housing to form a unitary article, the reed switch being secured to the switch plate in a predetermined relative alignment to the guide path of the plunger so that the longitudinal axis of the reed switch is substantially parallel to the longitudinal axis of the plunger, the plunger being movable between a first position in which the magnetic field and the reed switch interact to cause the reed switch to assume a first switching condition and a second position in which the magnetic field and the reed switch interact to cause the reed switch to assume a second switching condition; the plunger and reed switch being constructed and arranged so that the reed switch assumes the first switching condition when the longitudinal axis of the plunger is transversely aligned to the longitudinal axis of the reed switch. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In a tamper-resistant alarm lock switch assembly to that prevents movement of a movable barrier, the switch assembly including a plunger housing supporting a movable elongate plunger that has a longitudinal axis and that moves relative to the plunger housing along a guide path between first and second positions, a method of actuating a reed switch having a longitudinal axis in response to movement of the plunger or tampering with the alarm lock switch assembly, comprising:
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providing within the plunger a permanent magnet having an axis that substantially coincides with the longitudinal axis of the plunger and that produces a magnetic field; and assembling a switch plate supporting a magnetically actuatable reed switch and the plunger housing to form a unitary article, the reed switch being secured to the switch plate in a predetermined relative alignment to the guide path of the plunger so that the longitudinal axis of the reed switch is substantially parallel to the longitudinal axis of the plunger, the magnetic field of the permanent magnet actuates the reed switch into a first switching condition when the plunger is either in the first position or when the longitudinal axis of the reed switch is transversely aligned to the longitudinal axis of the plunger, and actuates the reed switch into a second switching condition when the plunger is in the second position. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A tamper-resistant alarm lock switch to prevent movement of a movable barrier comprising:
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an alarm lock switch housing including a reed switch cavity and a plunger having a longitudinal axis and movable along a guide path the plunger supported by the alarm lock switch housing to be moved along the guide path between a secure position and an alarm position, the plunger including a permanent magnet having an axis that substantially coincides with the longitudinal axis of the plunger and that produces a magnetic field; and a magnetically actuatable reed having a longitudinal axis switch positioned in the reed switch cavity of the alarm lock switch housing and in a predetermined relative alignment to the guide path so that the longitudinal axis of the reed switch is substantially parallel to the longitudinal axis of the plunger, the reed switch actuated into a secure switching condition by the magnetic field of the permanent magnet when the plunger is in the secure position and actuated into an alarm switching condition by the magnetic field of the permanent magnet either when the plunger is in the alarm position or when the longitudinal axis of the reed switch is transversely aligned to the longitudinal axis of the plunger. - View Dependent Claims (15, 16, 17, 18)
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Specification