Abstract: An anti-tamper assembly (40, 40a) is provided in order to sense the attempted removal of a body attached to a surface (17) by a fastener (36, 36a). The assembly (40, 40a) includes an anti-tamper access-blocking element (42, 42a) positioned in an anti-tamper position proximal to the fastener (36, 36a), along with an anti-tamper switch (44, 102) operably coupled with the element (42, 42a) in order to bias the switch (44, 102) to one switch condition. In the event that the element (42, 42a) is moved from its anti-tamper position, the switch (44, 102) moves to another switch condition, which generates an alarm signal. The assembly (40, 40a) may be used to protect an alarm section (16, 16a) forming a part of an alarm assembly (10, 10a). The section (16, 16a) includes a sensor or switch (64) operable to detect relative movement between first and second members such as a door (12) and doorframe (14).

Abstract: Tamper-resistant alarm switch assemblies (22, 100, 124, 148) are provided which include a first movement-sensing switch (24) and a second tamper-sensing switch assembly (25) including a switchable component (26) and an actuating component (74, 136, 166), mounted on a member (30) and each being switchable between respective first and second movement-sensing and tamper-sensing switch states in response to relative movement between first and second members (30, 32), and relative shifting between the switch (26) and actuating component (74, 136, 166).

Abstract: An anti-tamper assembly (40, 40a) is provided in order to sense the attempted removal of a body attached to a surface (17) by a fastener (36, 36a). The assembly (40, 40a) includes an anti-tamper access-blocking element (42, 42a) positioned in an anti-tamper position proximal to the fastener (36, 36a), along with an anti-tamper switch (44, 102) operably coupled with the element (42, 42a) in order to bias the switch (44, 102) to one switch condition. In the event that the element (42, 42a) is moved from its anti-tamper position, the switch (44, 102) moves to another switch condition, which generates an alarm signal. The assembly (40, 40a) may be used to protect an alarm section (16, 16a) forming a part of an alarm assembly (10, 10a). The section (16, 16a) includes a sensor or switch (64) operable to detect relative movement between first and second members such as a door (12) and doorframe (14).

Abstract: An improved magnetic switch (10) is provided which is designed for use in an alarm circuit (52) in order to detect relative movement between first and second members such as a door (14) and frame (12), so as to signal unauthorized opening of the door (14). The switch (10) includes a switch assembly (20) for mounting in frame (12) and having first and second switch elements (40, 42), an electrically conductive shiftable body (44) adjacent the elements (40, 42), and a first attractive component (45). Additionally, the switch (10) has a second attractive component (22) for mounting to the door (14). In use when door (14) is closed and circuit (52) is armed, the magnetic attraction between body (44) and component (22) shifts the body (44) to a switch position where the body (44) is out of simultaneous contact with the switch elements (40, 42).