| 摘要 |
<p>1510724 Releasable door hold-open mechanisms; stays RIXSON-FIREMARK INC 22 May 1975 [1 Aug 1974] 22317/75 Headings E2F and E2M A door hold-open mechanism comprises a stay arm 7 pivoted to the door and slidable within a channel in a door frame mounted housing 5, a bar 10 supported within the housing along which a slider 21 (attached to the end of arm 7) can move, and means to cause engagement between slider 21 and arm 10 in a plurality of positions to hold the door open. The arm 10 is attached to pivoted linkages 12, 13 and is provided with a friction strip 23; a toothed cam 20 is pivoted to the slider and is biassed by 25 to the position shown in Fig. 8. Opening movement of the door causes slider 21 to move along slot 22 and the cam 20 to rotate so as to oppose closing movement as shown in Fig. 9. The linkages 12, 13 allow the bar 10 to move away from the cam 20 but a spring 15 maintains the bar against the cam unless sufficient manual closing force is exerted on the door to move the bar back against its spring. The spring 15 is secured to a pivoted linkage 14 which carries an armature 17 engaged against an energized solenoid 18. If the current to the solenoid is cut off, either manually or by a fire and smoke detection system, then armature 17 is released and linkage 14 pivots back to release spring 15- Fig. 13. The bar 10 no longer acts against the cam 20 and the door is free to close-by its own weight, or by means of a closer mechanism 9. An ionization detector can be employed as a smoke detector (Fig. 16 not shown).</p> |
