Automatic hold-open release

Claim 1

AN AUTOMATICALLY RELEASABLE DOOR HOLD-OPEN MECHANISM COMPRISING, A SLIDE ELEMENT ADAPTED FOR RECIPROCABLE MOVEMENT RELATIVE TO A DOOR AND ALONG A PREDETERMINED PATH, A LINK ARM PIVOTED AT ONE END TO THE SLIDE ELEMENT AND HAVING ITS OTHER END ADAPTED FOR PIVOTAL CONNECTION AT A FIXED LOCATION FOR EFFECTING THE RECIPROCATION OF THE SLIDE ELEMENT ALONG SAID PATH INTO AND OUT OF A RETRACTED DOOR HOLD-OPEN POSITION BY MOVEMENT OF THE DOOR, LATCH MEANS SHIFTABLE INTO AND OUT OF THE PATH OF THE SLIDE ELEMENT FOR NORMALLY RETAINING THE SLIDE ELEMENT IN ITS RETRACTED POSITION, ELECTRIC MOTOR MEANS FOR NORMALLY HOLDING THE LATCH MEANS IN THE PATH OF THE SLIDE ELEMENT SO LONG AS THE MOTOR MEANS IS ENERGIZED, SAID MOTOR MEANS BEING ADAPTED TO RELEASE SAID LATCH MEANS UPON BEING DEENERGIZED, AND RESILIENTLY YIELDABLE MEANS NORMALLY COACTING WITH SAID MOTOR MEANS TO SUPPORT SAID LATCH MEANS IN THE PATH OF SAID SLIDE ELEMENT AND ADAPTED TO YIELD FOR RETRACTION OF SAID LATCH MEANS UPON THE APPLICATION OF A PREDETERMINED FORCE AGAINST THE LATCH MEANS BY SAID SLIDE ELEMENT BEING URGED ALONG SAID PATH BY SAID LINK ARM.