Abstract: An electromagnetic door lock system, allowing emergency exiting of a building, including an armature mount allowing considerable outward movement of the door with respect to the door frame on which the electromagnet is mounted, whereby outward movement of the door initiates a time delay door release, and gives an increased reassurance that the door will open in an emergency, and allows for improved tamper resistance and reduced false alarms, as the distance the door opens out of the door frame in response to actuation of a panic bar from within is greater than that of conventional systems. A tamper resistant door position sensor includes redundant magnetic reed switches for sensing the position of the door and can include an additional reed switch for detecting when an external magnet is placed near the sensor in an attempt to tamper with the system.

Abstract: An electromagnetic lock and status detection system and method therefor includes an armature, an electromagnet, and a status detection unit. The electromagnet is magnetically attracted to the armature into a mating relationship. A relatively high inductance is established in the electromagnet when the electromagnet is properly mated with the armature, and a relatively low inductance is established in the electromagnet when the electromagnet is not properly mated with armature. The status detection unit is coupled to the electromagnet to monitor the locking strength between the electromagnet and the armature. The unit monitors the locking strength by altering voltage level provided to the electromagnet and measuring the counter EMF induced in the electromagnet.

Abstract: A shear-type electromagnetic lock is disclosed whose armature can approach the electromagnet from any transverse direction, which can be mounted in any orientation with respect to gravity, and which does not require any door position sensing means. The armature includes a pair of standoffs in the form of conically projecting buttons affixed thereto, the buttons projecting from the plane of contact between the armature and the electromagnet. The buttons have a base angle of 60-80 degrees adjacent the armature, and an angle of 45 degrees distal from the armature, and terminate in a smoothly rounded point. The armature is mounted to a sub-plate via counteracting springs such that the armature "floats" on the sub-plate, with the distance between the armature and the sub-plate being adjustable via adjusting screws.

Abstract: A shear-type electromagnetic lock is disclosed whose armature can approach the electromagnet from any transverse direction, which can be mounted in any orientation with respect to gravity, and which does not require any door position sensing means. The armature includes a pair of standoffs in the form of conically projecting buttons affixed thereto, the buttons projecting from the plane of contact between the armature and the electromagnet. The buttons have a base angle of 60-80 degrees adjacent the armature, and an angle of 45 degrees distal from the armature, and terminate in a smoothly rounded point. The armature is mounted to a sub-plate via counteracting springs such that the armature "floats" on the sub-plate, with the distance between the armature and the sub-plate being adjustable via adjusting screws.

Abstract: A monitoring device for narrow stile, metal frame doors having a mounting plate securable to the door jamb adjacent the strike slot. A switch is mounted on a bracket extending from the face plate and the switch is connectable to an existing alarm system. A trigger normally engages the switch actuator pin. When the closure or door is closed and the dead bolt engaged in the strike slot, the trigger will disengage the pin allowing the alarm system to be armed.

Abstract: A high security deadbolt assembly for a door which bolt has a housing extending from the edge of the door inwardly of the transverse bore between the door surface. A deadbolt is reciprocable in the housing and has a recess at its inner end. A cylindrical drive member is rotatively supported in the housing and is located with or is aligned with the deadbolt recess. The drive member carries a stop and is connected to the bolt by a linkage. When locked, a substantial portion of the length of the bolt remains engaged in the bolt housing and door so that attempts at forcing the bolt to the unlocked position are resisted by the stop which stop engages an internal surface of the bolt recess. The components are made from high strength materials and the deadbolt assembly may be retrofit to existing lock cylinders with a minimum of installation modifications.

Abstract: An impact resistant electromagnetic lock includes an electromagnet mounted on a door frame, a ferromagnetic strike plate, and an impact-absorbing assembly for mounting the strike plate to the door. The impact-absorbing assembly fits largely within the door, and includes both a plunger coupled to the strike plate and a spring. When an inertial force directed to forcing the door open such as a kick is directed against the door, the plunger compresses the spring. The resilience provided by the spring allows the door a limited amount of inertia-absorbing linear movement, thus greatly decreasing the maximum force experienced by the door and correspondingly increasing the ability of the door to withstand the inertial attack.

Abstract: A closure latch or bolt monitoring device having a housing mountable in a closure frame which housing receives a latch or bolt. A pivotal rocker plate is normally biased to a rest position in which a flange portion of the rocker engages a switch connectable to an alarm system. When a latch or bolt is extended into the housing, the rocker plate is pivoted causing it to disengage from the switch providing an indication to the alarm system that the bolt or latch is properly engaged in the closure. An alternate embodiment allows separate monitoring of two lock components such as a separate bolt and latch.

Abstract: An electromagnetic lock for doors includes a large electromagnet mounted on the door frame, and a strike plate or armature secured to the door. A double-throw, double-pole type of relay or other switching circuit serves to selectively connect the electromagnet to receive rectified current when it is energized, and to receive a reverse pulse from a large capacitor when the door circuitry is de-energized. The large capacitor is charged to the same voltage as the electromagnet to insure full reversal of the magnetic domains to prevent residual magnetism. The double-throw, double-pole switch may be actuated by a high speed relay to insure timely switching of the contacts to apply reverse current from the capacitor to the electromagnet. The relay coil may be a latching relay which is selectively actuated in one direction while the circuit is energized, and is reversed as the electromagnet is discharged, so that it draws no current except when it is being switched on.

Abstract: Magnetic door locks characteristically include a high strength electromagnet and a mating plate made of magnetically permeable material, or door strike, mounted on the door frame and the door, respectively. In addition, in order to determine whether the door strike is in engagement with the electromagnet, detection arrangements are provided; and in the present case, simplified detection arrangements are provided by separate portions of the electromagnetic core separated by non-conducting shims or the like, and the closing of a detection circuit extending between the two portions of the electromagnetic core by the magnetic and electrically conducting door strike bridging between the two sections of the core. In addition, the detection circuit may be electrically connected in parallel with electromagnet energization circuit, to positively indicate both that the electromagnet is energized and that the door is closed.