Tamper detection mechanism
First Claim
1. A system for detecting unauthorized movement of a communications/meter device, the system comprising:
- at least one device attachment mechanism, having a selected attachment direction, that attaches a communications/meter device to a selected attachment site;
a magnetic field source, associated with the attachment mechanism, that provides a first magnetic field with a first field direction and a second magnetic field with a second field direction when the attachment mechanism is in a first selected position and in a second selected position, respectively;
a field-activated magnetic switch, positioned adjacent to the attachment mechanism and arranged so that, when the first magnetic field is applied to the switch, the switch is in a first switch state, and when the second magnetic field is applied to the switch, the switch is in a second switch state, distinct from the first switch state; and
an electrical current source, connected to said field-activated magnetic switch at a first selected location, that provides a current through said switch;
an electrical current sensor, connected to the field-activated magnetic switch at a second selected location, that senses a first level of current through the switch; and
an alarm, coupled to the current sensor, that generates a selected alarm signal when the switch is not in the first switch state, upon the sensed level of current in the current sensor.
1 Assignment
0 Petitions
Accused Products
Abstract
System and method for detecting an unauthorized movement of a communications or meter device, such as a meter that monitors and communicates a measure of use of energy or some other metered quantity (electrical, gas, water, etc.), to prevent meter tampering or removal. A bolt, screw, nail or other attachment mechanism, used to attach the device to a selected stationary or movable object, is provided with a permanent magnet having a selected magnetic field direction that can be transverse to, a selected attachment mechanism direction (e.g., transverse to a bolt shaft direction). A field-activated magnetic switch, such as a reed switch or a Hall effect switch, having a selected switch direction is located near the permanent magnet. If a user attempts to remove, or tamper with the position of, the communications device, by rotating or translating the attachment mechanism, the direction and/or magnitude of the magnetic field changes sufficiently to switch the switch from a first state (normal) to a second state (alarm), and an alarm signal is generated. In a second embodiment, a plunger connected to a micro switch is moved by a contact portion of an attachment mechanism as the attachment mechanism rotates or translates. In a third embodiment, the attachment mechanism is provided with an electrically conducting part and a non-conducting part, and a current-sensing or voltage-sensing circuit is movably connected to the mechanism at two spaced apart locations.
-
Citations
21 Claims
-
1. A system for detecting unauthorized movement of a communications/meter device, the system comprising:
-
at least one device attachment mechanism, having a selected attachment direction, that attaches a communications/meter device to a selected attachment site;
a magnetic field source, associated with the attachment mechanism, that provides a first magnetic field with a first field direction and a second magnetic field with a second field direction when the attachment mechanism is in a first selected position and in a second selected position, respectively;
a field-activated magnetic switch, positioned adjacent to the attachment mechanism and arranged so that, when the first magnetic field is applied to the switch, the switch is in a first switch state, and when the second magnetic field is applied to the switch, the switch is in a second switch state, distinct from the first switch state; and
an electrical current source, connected to said field-activated magnetic switch at a first selected location, that provides a current through said switch;
an electrical current sensor, connected to the field-activated magnetic switch at a second selected location, that senses a first level of current through the switch; and
an alarm, coupled to the current sensor, that generates a selected alarm signal when the switch is not in the first switch state, upon the sensed level of current in the current sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 20)
-
-
12. A method for detecting unauthorized movement of a communications/meter device, the method comprising the steps of:
-
providing at least one device attachment mechanism, having a selected attachment direction, that attaches a communications/meter device to a selected attachment site;
providing a magnetic field source, associated with the attachment mechanism, that provides a first magnetic field with a first field direction and a second magnetic field with a second magnetic field direction when the attachment mechanism is in a first selected position and in a second selected position, respectively;
positioning a field-activated magnetic switch, positioned adjacent to the attachment mechanism and arranged so that, when the first magnetic field is applied to the switch, the switch is in a first switch state, and when the second magnetic field is applied to the switch, the switch is in a second switch state, distinct from the first switch state; and
providing an electrical current source connected to the field-activated magnetic switch at a first selected location that provides a current through the switch;
providing an electrical current sensor, connected to the field-activated magnetic switch at a second selected location, that senses a level of current through the switch;
coupling an alarm to the electrical current sensor; and
generating a selected alarm signal by the alarm when the switch is not in the first switch state, upon the sensed level of current in the current sensor. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 21)
-
Specification