herein the phrase u201c within u201d the door will be understood to mean u201c at least partially within u201d the door plunger 46 is free to move a distance of about one inch 2 54 cm if maximum possible travel distance is desired armature mounting bolt head 44 could be formed such that plunger 46 extends into head 44 when the system is in its unforced state in theory this would allow plunger 46 to move a distance as much as or even more than the width of door 10 by allowing the plunger to move within the distance defined by the door thickness the present invention achieves a much greater movement distance than could be achieved with prior art systems these prior art systems provided only limited movement of the door since slack was provided only within the armature plate since typical armature plates are on the order of one half inch 1 27 cm the total allowed lineal movement was small in contrast a typical security door is on the order of 1 u00be inch 3 4 cm thick the present system therefore allows travel distances of at least about one inch 2 54 cm there are several advantages to this greater travel distance the first is that the activation distance 50 u2032 can be set far enough such that clearances within the space of the usual slack in the latch will not cause a false initiation of the system a second advantage is that it provides greater tactile and visual feedback to the person attempting to make an emergency exit this provides greater assurance to a possibly panic stricken individual that the door is functioning properly and.