Emergency exit door latch with hydraulic and electronic delay

An emergency exit door securing system wherein the system is used to secure a door member with respect to a door frame member, the system comprising:

• a keeper mounted on one of the members;
• a latching mechanism mounted on the other member, the latching mechanism including:
• base means for mounting various components of the latching mechanism;
• bolt means for latchably engaging the keeper and means for movably mounting the bolt means on the base member;
• bolt dogging means mounted for movement on said base member between a dogging mode and undogging mode, the bolt dogging means including:
• a toggle linkage which is held in a jambed position when the bolt is dogged and is allowed to collapse when the bolt is undogged;
• means for gradually displacing a fluid, said fluid displacing means being connected between the bolt means and bolt dogging means to allow the bolt means to release the keeper after sufficient fluid has been displaced, and
• means for selectively retaining the bolt-dogging means in either the dogged mode or the undogged mode;
• means for releasing the retaining means;
• means for operating the release means, said operating means including a timer and means for sensing when an attempt is made to open the door, said sensing means being connected to the timer for starting the timer to count a time interval upon an attempt to open the door and to thereafter allow the release means to undog the bolt means, whereby opening of the door is delayed after an attempt to open the door occurs, and
• means for indicating that an attempt is being made to open the door.

A system for securing at least one emergency exit door of an enclosure while providing for emergency opening of the emergency exit door to provide egress from the enclosure, the system comprising:

• securing means for preventing the door from opening when a securing means is in a first mode;
• and for allowing the door to open when the securing means is in the second mode;
• the securing means including a bolt and a keeper, which bolt is in a latched position with respect to the keeper when the securing means is in the first mode and in an unlatched position with respect to the keeper when the securing means is in the second mode;
• means for mounting the bolt for movement between the first and second positions;
• retaining means included with the securing means for retaining the securing means in the first mode;
• releasing means connected to the retaining means and operating the retaining means for allowing the securing means to shift to the second mode;
• electrical switch means for providing a signal indicating that an attempt to open the door is occurring;
• electrical timing means connected to the electrical switch means and started by the signal from the electrical switch means to generate a release signal after a predetermined time interval, the electrical timing means being connected to the releasing means to thereby allow the securing means to shift from the first mode to the second mode;
• means for throttling a fluid, the fluid throttling means being connected to the bolt for delaying movement of the bolt from the first position to the second position when a force is applied to the bolt by the keeper tending to move the bolt from the first to the second position;
• the fluid throttling means being independent of the retaining means, electrical timing means, releasing means and electrical switch means for providing a redundant delay which can still release the bolt if the retaining means, the electrical timing means, the releasing means or the electrical switch means fail to release the bolt;
• means for indicating that an attempt has been made to open the door.