# US 5,353,015 A · Tamper detector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,353,015 A - Document ID: US5353015A - Status: Granted - Kind: A - Application number: 07/877,954 - Filed: 1992-04-23 - Granted: 1994-10-04 - Earliest claimed: 1992-04-23 - Assignees: The United States of America as represented by the Secretary of the Air Force - Inventors: Wesley A. Robinson - Web page: https://patentgrep.com/patent/US5353015A ## CPC - G08B 13/1409: {for removal detection of electrical appliances by detecting their physical disconnection from an electrical system, e.g. using a switch incorporated in the plug connector} - G08B: SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS ## Abstract The unauthorized separation of a second member such as a door with respect to a first member affixed to a computer frame and the subsequent replacement of the initial position of the door creates a change of state of a square loop magnetic member integral with the computer frame. This change of state can be monitored from time to time to indicate an unauthorized opening of the door. ## Claims ### Claim 1 A tamper indicator for indicating to monitoring personnel that separation of a first member and a second member which is in contact with said first member upon inspection thereof by said monitoring personnel has occurred prior to said inspection, wherein said first member comprises: (a) a permanent magnet having a first pole and a second pole of a polarity opposite said first pole; (b) a first elongated soft magnetic flux conductor magnetically coupled to the first pole of said permanent magnet and having a first terminal portion and a second terminal portion; (c) a second elongated soft magnetic flux conductor magnetically coupled to the second pole of said permanent magnet and having a first terminal portion and a second terminal portion; and (d) a square loop magnetic member magnetically coupled between the first terminal portion of said first elongated soft magnetic flux conductor and the first terminal portion of said second elongated soft magnetic flux conductor; and wherein said second member is made of a soft magnetic material for conducting flux between the second terminal portions of said first and second elongated soft magnetic flux conductors; and said tamper indicator further including detector means coupled to said square loop magnetic member for detecting the state of magnetization thereof. ### Claim 2 (depends on 1) The tamper indicator of claim 1 further including reset means for reversing the state of magnetization of said square loop magnetic member. ### Claim 3 (depends on 2) The tamper indicator of claim 2 wherein said second member is coupled to a door. ### Claim 4 (depends on 1) The tamper indicator of claim 1 wherein said second member is coupled to a door. ### Claim 5 A tamper indicator for indicating to monitoring personnel that separation of a first member and a second member which is in contact with said first member upon inspection thereof by said monitoring personnel has occurred prior to said inspection, wherein said first member comprises: (a) a permanent magnet having a first pole and a second pole of a polarity opposite said first pole; (b) a first soft magnetic flux conductor magnetically coupled to the first pole of said permanent magnet and having a first portion and a second portion; (c) a second soft magnetic flux conductor magnetically coupled to the second pole of said permanent magnet and having a first portion and a second portion; and (d) a square loop magnetic member magnetically coupled between the first portion of said first soft magnetic flux conductor and the first portion of said second magnetic flux conductor; and wherein said second member is made of a soft magnetic material for conducting flux between the second portions of said first and second soft magnetic flux conductors; and said tamper indicator further including detector means coupled to said square loop magnetic member for detecting the state of magnetization thereof. ### Claim 6 (depends on 5) The tamper indicator of claim 5 further including reset means for reversing the state of magnetization of said square loop magnetic member. ### Claim 7 (depends on 6) The tamper indicator of claim 6 wherein said second member is coupled to a door. ### Claim 8 (depends on 5) The tamper indicator of claim 5 wherein said second member is coupled to a door. ### Claim 9 A tamper indicator for indicating to monitoring personnel that separation of a first member and a second member which is in contact with said first member upon inspection thereof by said monitoring personnel has occurred prior to said inspection, wherein said first member comprises: (a) a permanent magnet having a first pole and a second pole of a polarity opposite said first pole; (b) a first elongated soft magnetic flux conductor magnetically coupled to the first pole of said permanent magnet and having a first terminal portion and a second terminal portion; (c) a second elongated soft magnetic flux conductor magnetically coupled to the second pole of said permanent magnet and having a first terminal portion and a second terminal portion; and (d) a square loop magnetic member magnetically coupled between the first terminal portion of said first elongated soft magnetic flux conductor and the first terminal portion of said second elongated soft magnetic flux conductor; and wherein said second member is made of a soft magnetic material for conducting flux between the second terminal portions of said first and second elongated soft magnetic flux conductors; and wherein said second member is coupled to a door. ### Claim 10 A tamper indicator for indicating to monitoring personnel that separation of a first member and a second member which is in contact with said first member upon inspection thereof by said monitoring personnel has occurred prior to said inspection, wherein said first member comprises: (a) a permanent magnet having a first pole and a second pole of a polarity opposite said first pole; (b) a first soft magnetic flux conductor magnetically coupled to the first pole of said permanent magnet and having a first portion and a second portion; (c) a second soft magnetic flux conductor magnetically coupled to the second pole of said permanent magnet and having a first portion and a second portion; and (d) a square loop magnetic member magnetically coupled between the first portion of said first soft magnetic flux conductor and the first portion of said second magnetic flux conductor; and wherein said second member is made of a soft magnetic material for conducting flux between the second portions of said first and second soft magnetic flux conductors; and wherein said second member is coupled to a door.