Tamper-resistant magnetic security system
First Claim
1. A security system for use in a physical security monitoring environment, said system comprisinga sensor unit having a common conductor, an alarm conductor, and a guard conductor and at least three switches, each of said switches having a deactivated condition and an activated condition and being adapted to be placed in its activated condition in response to a magnetic field of predetermined magnetic flux density;
- said sensor unit having a logic circuit electrically interconnecting said switches and said common conductor, said alarm conductor and said guard conductor, said logic circuit completing a series circuit between said common conductor and said guard conductor whenever a predetermined one of said switches is in a deactivated condition and the remaining switches are in an activated condition, and completing a circuit between said common conductor and said alarm conductor when either all of said switches are in an activated condition or one of said remaining switches is in a deactivated condition; and
an actuator unit with at least two permanent magnets, the number of said permanent magnets being one less than the number of said switches and each said permanent magnet providing a discrete magnetic field of predetermined flux density sufficient to activate a corresponding one of said switches when said actuator unit is located in a predetermined juxtaposition with respect to said sensor unit.
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Accused Products
Abstract
A security system for use in a physical security monitoring environment includes a switch unit having a common conductor, a guard conductor and at least three switches. Each of the switches has a deactivated condition and an activated condition and each is adapted to be placed in its activated condition in response to a magnetic field of predetermined magnetic flux. The switch unit also includes a logic circuit electrically interconnecting the switches and the common and guard conductors, the logic circuit completing a series circuit between the common conductor and the guard conductor whenever at least two predetermined but not all switches are in magnetically actuated condition. An associated actuator unit includes at least two permanent magnets and provides discrete magnetic fields of predetermined flux density and position sufficient to activate the two or more predetermined switches individually to complete the series circuit between the common conductor and the guard conductor when the actuator unit is located in predetermined juxtaposition with respect to the sensor unit.
36 Citations
17 Claims
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1. A security system for use in a physical security monitoring environment, said system comprising
a sensor unit having a common conductor, an alarm conductor, and a guard conductor and at least three switches, each of said switches having a deactivated condition and an activated condition and being adapted to be placed in its activated condition in response to a magnetic field of predetermined magnetic flux density; -
said sensor unit having a logic circuit electrically interconnecting said switches and said common conductor, said alarm conductor and said guard conductor, said logic circuit completing a series circuit between said common conductor and said guard conductor whenever a predetermined one of said switches is in a deactivated condition and the remaining switches are in an activated condition, and completing a circuit between said common conductor and said alarm conductor when either all of said switches are in an activated condition or one of said remaining switches is in a deactivated condition; and an actuator unit with at least two permanent magnets, the number of said permanent magnets being one less than the number of said switches and each said permanent magnet providing a discrete magnetic field of predetermined flux density sufficient to activate a corresponding one of said switches when said actuator unit is located in a predetermined juxtaposition with respect to said sensor unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A security system for use in a physical security monitoring environment, said system comprising
a sensor unit having a common conductor, an alarm conductor, and a guard conductor and three switches, each of said switches having a deactivated condition and an activated condition and being adapted to be placed in its activated condition in response to a magnetic field of predetermined magnetic flux density; -
said sensor unit having a logic circuit electrically interconnecting said switches and said common conductor, said alarm conductor and said guard conductor, said logic circuit completing a series circuit between said common conductor and said guard conductor whenever a predetermined one of said switches is in a deactivated condition and the other two switches are in an activated condition, and completing a circuit between said common conductor and said alarm conductor when either all of said switches are in an activated condition or one of said other two switches is in a deactivated condition; and an actuator unit including two permanent magnets, each said permanent magnet being positioned to activate a corresponding switch such that only two of said three switches are activated to complete said series circuit between said common conductor and said guard conductor when said actuator unit is located in a predetermined juxtaposition with respect to said sensor unit. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification