Abstract: A door mounted in a door frame is held closed by an electromagnet mounted on the door frame which magnet attracts an armature mounted on the door. A switch is mounted adjacent to the electromagnet and is operated by a switch operator mounted on the door. The switch provides a signal indicating that an attempt is being made to open the door, which signal may be used to sound an alarm or start a time delay release. A pair of contacts are also mounted adjacent to the electromagnet and are bridged by the armature to indicate when the armature is properly held by the electromagnet.

Abstract: A magnetic door lock with a time delay option includes an electromagnet mounted on a door frame and an armature mounted on a door. The electromagnet has a pair of laterally spaced slots therein which each have a reed switch therein for monitoring magnetic flux in the electromagnet. When the armature is engaged with the electromagnet, the magnetic flux is at a selected level sufficient to close the reed switches. If, due to tampering or some other reason, the magnetic flux drop does not reach the selected level, at least one of the reed switches will remain open indicating that the armature is not securely engaged with the electromagnet. The door lock also includes separate mounting plates for mounting the electromagnet and armature so that the electromagnet and armature will be properly aligned when mounted. A plunger is provided adjacent the electromagnet for engagement by a block adjacent the armature. When an attempt is made to open the door, the plunger moves thereby sensing the attempt.

Abstract: A door mounted in a door frame is held closed by an electromagnet mounted on the door frame which magnet attracts an armature mounted on the door. A switch is mounted adjacent to the electromagnet and is operated by a switch operator mounted on the door. The switch provides a signal indicating that an attempt is being made to open the door, which signal may be used to sound an alarm or start a time delay release. A pair of contacts are also mounted adjacent to the electromagnet and are bridged by the armature to indicate when the armature is properly held by the electromagnet.

Abstract: A door latch mechanism has a pivoted latch disposed between a retaining solenoid and a four-bar toggle linkage. The toggle linkage connects the operating stem of the solenoid to the latch, has an under-the-center arrangement in a direction away from the solenoid in the latched position of the mechanism, and provides a substantial mechanical advantage to amplify the holding force of the solenoid. When the solenoid is de-energized and pressure is applied to open the door, the latch pivots and the toggle linkage collapses to release the keeper bar. The keeper bar is trapped but has a limited movement in both horizontal and vertical directions in a plane substantially parallel to the pivot axis of the latch. The overall arrangement is relatively simple, compact, inexpensive, easy to install, and reliable in its operation.

Abstract: Apparatus for securing an emergency exit door includes a bolt for engaging a keeper, a dogging mechanism for dogging the bolt and a fluid throttling device disposed between the bolt and dogging mechanism. An electrical timer is connected to the dogging mechanism by a solenoid and starts to count upon an attempt to open the door. After a predetermined time interval has run, the electrical timer releases the dogging mechanism and allows the door to open. If the electrical timer fails to release the dogging mechanism, the door will still open if pushed due to operation of the fluid throttling device, which slowly shortens under pressure, allowing the bolt to clear the keeper.In order to readily align the keeper with the bolt, the keeper is loosely mounted and guided into alignment with the bolt by a bevelled guide. Upon being latched by the bolt, the keeper is held rigidly between the guide and the bolt.

Abstract: In order to secure an emergency exit door against unauthorized opening from the inside, a retrofit delay mechanism is attached to the door frame. The delay mechanism includes a retractable bolt which projects behind a strike mounted on the door. A piston is attached to the bolt and a hydraulic circuit is connected to the piston. The hydraulic circuit includes a throttle and a normally open valve. The normally open valve is held closed by a solenoid. Upon attempting to open the door, fluid in the hydraulic circuit is throttled slowing down retraction of the bolt and delaying opening of the door. The solenoid which releases the normally open valve is connected to a timing circuit which de-energizes the solenoid after a predetermined time interval thus providing a redundant delay arrangement. Smoke detectors, fire pull-boxes and a remote reset switch are also connected to the solenoid via a dropout relay.

Abstract: Emergency exit door latching and locking apparatus includes a closure operated latch bolt which is mounted in a U-shaped pivoted carrier link by a pair of links for projection from the carrier link to latch the door. The carrier link is connected to a toggle linkage which in a first position dogs the carrier link and bolt projected and when urged over-center allows the carrier link to pivot so as to carry the bolt to a retracted position while the bolt is still projected from the carrier link. A panic push bar is used to move the toggle over-center and to thereafter engage a projection on the door so as to urge the bolt to the retracted position due to pressure applied on the door. A detent is disposed to move between the bolt and pivot for the carrier link so as to keep the bolt projected when the detent engages a strike on the door jamb. When the door is moved from the open position to the closed position, the detent is disengaged from the pivot and the bolt retracts into the carrier link.

Abstract: An emergency exit door lock equipped with a delay is provided with exterior unlatching and unlocking arrangements which permit a door normally locked with respect to the outside to have a bolt which is undogged and retracted from the outside. Upon undogging the bolt from the outside, the delay is deactivated by de-energizing a solenoid which controls application of the delay.

Abstract: Opening of a door, such as an emergency exit door, is delayed by encumbering a security device, such as for example a latch bolt, with the task of throttling a hydraulic fluid through a circuit, which circuit includes a normally open valve held closed by a solenoid. When the solenoid is de-energized, the circuit is opened allowing the security device to move so that the door can be opened. The solenoid is controlled by an electrical timing circuit which delays de-energization of the solenoid. The timing circuit is started by a switch mounted to be operated by movement of the latch bolt. Preferably in a situation where there are a plurality of doors, doors proximate to one another are delayed by the same electronic timing circuit. In a preferred embodiment, the electronic timing circuit is set to de-energize the solenoid at a time subsequent to the delay resulting from throttling the fluid.

Abstract: Opening of a door, such as an emergency exit door, is delayed by a door check, the operation of which has been reversed to delay opening of the door instead of delaying closing of the door. The delay is accomplished by a circuit which includes a normally open valve held closed by a solenoid. When the solenoid is de-energized, the circuit is opened allowing the reversed door check to operate so that the door can be opened. The solenoid is controlled by an electrical timing circuit which is started by a switch connected to a door operator such as a push bar.

Abstract: An emergency release for key operated deadlocks includes a ram rod for forcing a deadbolt out of a keeper so as to allow a deadlocked door to open under emergency conditions. The release further includes a yieldable element disposed between the key operator for the deadbolt, which yieldable element deforms as the deadbolt is forced back by the ram. An alarm is activated upon operation of the emergency release to discourage intruders from trying to open the door with the emergency release. Preferably, the rod is advanced by a rack-and-pinion arrangement which is operated by a wire coiled around a spool.

Abstract: A magnetic emergency exit door locking system includes a magnetic lock with an armature securred to an emergency exit door and a coil to the lintel of the door. The coil is connected to a power supply and keeps the door locked as long as the power supply applies current thereto. A drop-out relay is disposed in the line between the power supply and coil to interrupt current to the coil when operated. The drop-out relay is operated by a switch which is tripped upon pushing the push-bar on the door. In order to prevent immediate opening of the door upon pressing the push-bar, a timer is disposed between the switch and the drop-out relay to delay unlocking of the door for a selected interval having a duration of, perhaps, fifteen (15) to forty (40) seconds. An alarm sounds during this interval to give notice that someone is trying to open the door.