| 摘要 |
1283518 Releasable fastenings; door operation mechanism WILLIAM NEWMAN & SONS Ltd 19 April 1971 [15 July 1970] 34268/70 Headings E2A and E2M A door is held in an open position by means of an electromagnet and is moved to a closed position by means of a door-closer device when the current supply to the electromagnet is interrupted by fire detection or alarm means, for example. In an embodiment an electromagnet 3 Fig. 1, is housed in a casing 1, the latter also containing a slide 2 therein. The slide 2 comprises a body 4 of synthetic plastics material, for example, having a magnetic member 5 held thereto by means of a screw 6, and a pivot 11, Fig. 2, which is connected to an arm 12 of a spring door-closure device S, Fig. 6. A layer 7, Fig. 1, of foam rubber is positioned between the body 4 and the magnetic member 5 and a foam rubber liner 8 is provided in a screw-hole 9 of the magnetic member 5. The pivot 11, Fig. 2, extends through a slot 10 formed in the casing 1 and has a nylon bush 13 mounted thereon. In use, when the door is closed as shown in Fig. 1 the slide 2 is remote from the electromagnet 3. When the door is being opened, the arm 12 moves angularly and causes the slide 2 to move towards the electromagnet 3. At the fully-opened position of the door the magnetic member 5 engages the electromagnet 3. |
